Science.gov

Sample records for ac pv modules

  1. AC photovoltaic module magnetic fields

    SciTech Connect

    Jennings, C.; Chang, G.J.; Reyes, A.B.; Whitaker, C.M.

    1997-12-31

    Implementation of alternating current (AC) photovoltaic (PV) modules, particularly for distributed applications such as PV rooftops and facades, may be slowed by public concern about electric and magnetic fields (EMF). This paper documents magnetic field measurements on an AC PV module, complementing EMF research on direct-current PV modules conducted by PG and E in 1993. Although not comprehensive, the PV EMF data indicate that 60 Hz magnetic fields (the EMF type of greatest public concern) from PV modules are comparable to, or significantly less than, those from household appliances. Given the present EMF research knowledge, AC PV module EMF may not merit considerable concern.

  2. Supported PV module assembly

    DOEpatents

    Mascolo, Gianluigi; Taggart, David F.; Botkin, Jonathan D.; Edgett, Christopher S.

    2013-10-15

    A supported PV assembly may include a PV module comprising a PV panel and PV module supports including module supports having a support surface supporting the module, a module registration member engaging the PV module to properly position the PV module on the module support, and a mounting element. In some embodiments the PV module registration members engage only the external surfaces of the PV modules at the corners. In some embodiments the assembly includes a wind deflector with ballast secured to a least one of the PV module supports and the wind deflector. An array of the assemblies can be secured to one another at their corners to prevent horizontal separation of the adjacent corners while permitting the PV modules to flex relative to one another so to permit the array of PV modules to follow a contour of the support surface.

  3. PV module mounting method and mounting assembly

    DOEpatents

    Lenox, Carl J.S.; Johnson, Kurt M.

    2013-04-23

    A method for mounting PV modules to a deck includes selecting PV module layout pattern so that adjacent PV module edges are spaced apart. PV mounting and support assemblies are secured to the deck according to the layout pattern using fasteners extending into the deck. The PV modules are placed on the PV mounting and support assemblies. Retaining elements are located over and secured against the upper peripheral edge surfaces of the PV modules so to secure them to the deck with the peripheral edges of the PV modules spaced apart from the deck. In some examples a PV module mounting assembly, for use on a shingled deck, comprises flashing, a base mountable on the flashing, a deck-penetrating fastener engageable with the base and securable to the deck so to secure the flashing and the base to the shingled deck, and PV module mounting hardware securable to the base.

  4. PSCAD Modules Representing PV Generator

    SciTech Connect

    Muljadi, E.; Singh, M.; Gevorgian, V.

    2013-08-01

    Photovoltaic power plants (PVPs) have been growing in size, and the installation time is very short. With the cost of photovoltaic (PV) panels dropping in recent years, it can be predicted that in the next 10 years the contribution of PVPs to the total number of renewable energy power plants will grow significantly. In this project, the National Renewable Energy Laboratory (NREL) developed a dynamic modeling of the modules to be used as building blocks to develop simulation models of single PV arrays, expanded to include Maximum Power Point Tracker (MPPT), expanded to include PV inverter, or expanded to cover an entire PVP. The focus of the investigation and complexity of the simulation determines the components that must be included in the simulation. The development of the PV inverter was covered in detail, including the control diagrams. Both the current-regulated voltage source inverter and the current-regulated current source inverter were developed in PSCAD. Various operations of the PV inverters were simulated under normal and abnormal conditions. Symmetrical and unsymmetrical faults were simulated, presented, and discussed. Both the three-phase analysis and the symmetrical component analysis were included to clarify the understanding of unsymmetrical faults. The dynamic model validation was based on the testing data provided by SCE. Testing was conducted at SCE with the focus on the grid interface behavior of the PV inverter under different faults and disturbances. The dynamic model validation covers both the symmetrical and unsymmetrical faults.

  5. Flexible packaging for PV modules

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.

    2008-08-01

    Economic, flexible packages that provide needed level of protection to organic and some other PV cells over >25-years have not yet been developed. However, flexible packaging is essential in niche large-scale applications. Typical configuration used in flexible photovoltaic (PV) module packaging is transparent frontsheet/encapsulant/PV cells/flexible substrate. Besides flexibility of various components, the solder bonds should also be flexible and resistant to fatigue due to cyclic loading. Flexible front sheets should provide optical transparency, mechanical protection, scratch resistance, dielectric isolation, water resistance, UV stability and adhesion to encapsulant. Examples are Tefzel, Tedlar and Silicone. Dirt can get embedded in soft layers such as silicone and obscure light. Water vapor transmittance rate (WVTR) of polymer films used in the food packaging industry as moisture barriers are ~0.05 g/(m2.day) under ambient conditions. In comparison, light emitting diodes employ packaging components that have WVTR of ~10-6 g/(m2.day). WVTR of polymer sheets can be improved by coating them with dense inorganic/organic multilayers. Ethylene vinyl acetate, an amorphous copolymer used predominantly by the PV industry has very high O2 and H2O diffusivity. Quaternary carbon chains (such as acetate) in a polymer lead to cleavage and loss of adhesional strength at relatively low exposures. Reactivity of PV module components increases in presence of O2 and H2O. Adhesional strength degrades due to the breakdown of structure of polymer by reactive, free radicals formed by high-energy radiation. Free radical formation in polymers is reduced when the aromatic rings are attached at regular intervals. This paper will review flexible packaging for PV modules.

  6. Ensuring Quality of PV Modules: Preprint

    SciTech Connect

    Kurtz, S.; Wohlgemuth, J.; Hacke, P.; Kempe, M.; Sample, T.; Yamamichi, M.; Kondo, M.; Doi, T.; Otani, K.; Amano, J.

    2011-07-01

    Photovoltaic (PV) customers need to have confidence in the PV modules they purchase. Currently, no test can quantify a module's lifetime with confidence, but stress tests are routinely used to differentiate PV product designs. We suggest that the industry would be strengthened by using the wisdom of the community to develop a single set of tests that will help customers quantify confidence in PV products. This paper evaluates the need for quality assurance (QA) standards and suggests a path for creating these. Two types of standards are needed: 1) QA of the module design and 2) QA of the manufacturing process.

  7. PV Module Reliability Research (Fact Sheet)

    SciTech Connect

    Not Available

    2013-06-01

    This National Center for Photovoltaics sheet describes the capabilities of its PV module reliability research. The scope and core competencies and capabilities are discussed and recent publications are listed.

  8. Lightweight PV Inverters: Dual Bi-Directional IGBTs Modules Enables Breakthrough PV Inverter Using Current Modulation Topology

    SciTech Connect

    2012-01-30

    Solar ADEPT Project: PV inverters convert DC power generated by modules into usable AC power. IPC’s initial 30kW 94lb. PV inverter reduces the weight of comparable 30kW PV inverters by 90%—reducing the cost of materials, manufacturing, shipping, and installation. With ARPA-E support, new bi-directional silicon power switches will be developed, commercialized, and utilized in IPC’s next-generation PV inverter. With these components, IPC will produce 100kW inverters that weight less than 100lb., reducing the weight of conventional 3,000lb. 100kW inverters by more than 95%. The new power switches will cut IPC’s $/W manufacturing cost in half, as well as further reduce indirect shipping and installation costs.

  9. Development of standardized, low-cost AC PV systems. Phase I annual report, 7 September 1995--7 November 1996

    SciTech Connect

    Strong, S.J.; Wohlgemuth, J.H.; Kaelin, M.

    1997-06-01

    The objectives of this two-year program are to improve the reliability and safety and reduce the cost of installed grid-connected PV systems by creating standardized, pre-engineered components and an enhanced, low-cost, 250-Watt micro inverter. These advances will be combined with the new, large area Solarex MSX-240 PV module resulting in standard, modular AC PV {open_quotes}building blocks{close_quotes} used to create utility-interactive PV systems as small as one module to many thousands of modules to suit virtually any application. AC PV building blocks will be developed to meet the requirements of the U.S., Japanese and European markets.

  10. PV modules with optimized energy balance

    NASA Astrophysics Data System (ADS)

    Weixlberger, Johann; Bruckner, Richard

    2011-09-01

    The overall energy balance of a solar PV-module across its life time needs a consideration incl. its energy consumption during manufacturing process versus its energy harvesting capabilities during life time. A glass-glass-module based on thin tempered glass on front and backside can dramatically influence this overall balance, since more than 50 % of encapsulation materials manufacturing energy can be saved, followed by a an further impact on frameless mounting of light-weighted modules, reducing mounting costs and enabling simpler BIPV.

  11. PV modules for ground testing

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The main objective was to design and build a minimum of three photovoltaic test panels for plasma interaction experiments. These experiments are intended to provide data on the interactions between high-voltage solar arrays and the space plasma environment. Data gathered will significantly contribute to the development of design criteria for the space station solar arrays. Electrical isolation between the solar cell strings and the module mounting plate is required for high-voltage bias.

  12. A new flexible a-Si PV module and its application to rooftop PV systems

    SciTech Connect

    Ichikawa, Yukimi; Ihara, Takuro; Hama, Toshio

    1994-12-31

    A novel photovoltaic (PV) module for roof top systems, solar roofing, was proposed. Solar roofing is a flexible amorphous silicon (a-Si) PV sheet having the function of roofing. Tempered glass is used as roof covering material. Technical items for roof top systems using solar roofing were discussed. Preliminary studies on module component materials showed feasibility of solar roofing. The authors designed a construction technology for tempered glass covered roofs. Effects of shadows on PV module upon its performance were also analyzed.

  13. Development of an AC Module System: Final Technical Report

    SciTech Connect

    Suparna Kadam; Miles Russell

    2012-06-15

    The GreenRay Inc. program focused on simplifying solar electricity and making it affordable and accessible to the mainstream population. This was accomplished by integrating a solar module, micro-inverter, mounting and monitoring into a reliable, 'plug and play' AC system for residential rooftops, offering the following advantages: (1) Reduced Cost: Reduction in installation labor with fewer components, faster mounting, faster wiring. (2) Maximized Energy Production: Each AC Module operates at its maximum, reducing overall losses from shading, mismatch, or module downtime. (3) Increased Safety. Electrical and fire safety experts agree that AC Modules have significant benefits, with no energized wiring or live connections during installation, maintenance or emergency conditions. (4) Simplified PV for a Broader Group of Installers. Dramatic simplification of design and installation of a solar power system, enabling faster and more efficient delivery of the product into the market through well-established, mainstream channels. This makes solar more accessible to the public. (5) Broadened the Rooftop Market: AC Modules enable solar for many homes that have shading, split roofs, or obstructions. In addition, due to the smaller building block size of 200W vs. 1000W, homeowners with budget limitations can start small and add to their systems over time. Through this DOE program GreenRay developed the all-in-one AC Module system with an integrated PV Module and microinverter, custom residential mounting and performance monitoring. Development efforts took the product from its initial concept, through prototypes, to a commercial product sold and deployed in the residential market. This pilot deployment has demonstrated the technical effectiveness of the AC Module system in meeting the needs and solving the problems of the residential market. While more expensive than the traditional central inverter systems at the pilot scale, the economics of AC Modules become more and more

  14. On the spectral response of PV modules

    NASA Astrophysics Data System (ADS)

    Ye, J. Y.; Guo, S.; Walsh, T. M.; Hishikawa, Y.; Stangl, R. A.

    2014-09-01

    The spectral response of silicon wafer based and thin-film photovoltaic (PV) modules is studied using simulation and experimental methods. Circuit simulations show that the module spectral response (SR) depends on (1) the SR of the cells, (2) the shunt resistance Rshunt of the cells, and (3) the bypass diodes of the module. For realistic Rshunt values, the module SR is significantly higher than the minimal SR of the individual cells (which would be the module SR in the case of infinite Rshunt). Round-robin tests using different experimental methods (partial illumination and full-area illumination) to determine the SR of a wafer-based module and a thin-film silicon module were conducted. Both SR methods are found to agree reasonably well. However, circuit simulations indicate that if only one cell, or a few cells, within the module have significantly different characteristics but not known, the results may differ considerably. The partial illumination method can access the SR of the individual cells within a module, but it possibly requires a long measurement time in order to measure the SR and Rshunt of each cell for confirming the SR of the whole module. In contrast, full-area illumination methods measure the module SR directly, but they cannot access the cell SRs if problematic cells exist. An uncertainty analysis of the full-area illumination method is conducted, which reveals that—if the calibrated reference cell is chosen properly—the calibration uncertainty of the reference cell itself is the main source of uncertainty.

  15. Evaluation of PV Module Field Performance

    SciTech Connect

    Wohlgemuth, John; Silverman, Timothy; Miller, David C.; McNutt, Peter; Kempe, Michael; Deceglie, Michael

    2015-06-14

    This paper describes an effort to inspect and evaluate PV modules in order to determine what failure or degradation modes are occurring in field installations. This paper will report on the results of six site visits, including the Sacramento Municipal Utility District (SMUD) Hedge Array, Tucson Electric Power (TEP) Springerville, Central Florida Utility, Florida Solar Energy Center (FSEC), the TEP Solar Test Yard, and University of Toledo installations. The effort here makes use of a recently developed field inspection data collection protocol, and the results were input into a corresponding database. The results of this work have also been used to develop a draft of the IEC standard for climate and application specific accelerated stress testing beyond module qualification. TEP Solar Test Yard, and University of Toledo installations. The effort here makes use of a recently developed field inspection data collection protocol, and the results were input into a corresponding database. The results of this work have also been used to develop a draft of the IEC standard for climate and application specific accelerated stress testing beyond module qualification. TEP Solar Test Yard, and University of Toledo installations. The effort here makes use of a recently developed field inspection data collection protocol, and the results were input into a corresponding database. The results of this work have also been used to develop a draft of the IEC standard for climate and application specific accelerated stress testing beyond module qualification.

  16. International PV QA Task Force's Proposed Comparative Rating System for PV Modules: Preprint

    SciTech Connect

    Wohlgemuth, J.; Kurtz, S.

    2014-10-01

    The International PV Quality Assurance Task Force is developing a rating system that provides comparative information about the relative durability of PV modules. Development of accelerated stress tests that can provide such comparative information is seen as a major step toward being able to predict PV module service life. This paper will provide details of the ongoing effort to determine the format of such an overall module rating system. The latest proposal is based on using three distinct climate zones as defined in IEC 60721-2-1 for two different mounting systems. Specific stresses beyond those used in the qualification tests are being developed for each of the selected climate zones.

  17. Role of Polycrystalline Thin-Film PV Technologies in Competitive PV Module Markets: Preprint

    SciTech Connect

    von Roedern, B.; Ullal, H. S.

    2008-05-01

    This paper discusses the developments in thin-film PV technologies and provides an outlook on future commercial module efficiencies achievable based on today's knowledge about champion cell performance.

  18. Applications of ``PV Optics`` for solar cell and module design

    SciTech Connect

    Sopori, B.L.; Madjdpour, J.; Chen, W.

    1998-09-01

    This paper describes some applications of a new optics software package, PV Optics, developed for the optical design of solar cells and modules. PV Optics is suitable for the analysis and design of both thick and thin solar cells. It also includes a feature for calculation of metallic losses related to contacts and back reflectors.

  19. How Can We Make PV Modules Safer?: Preprint

    SciTech Connect

    Wohlgemuth, J. H.; Kurtz, S. R.

    2012-06-01

    Safety is a prime concern for the photovoltaics (PV) industry. As a technology deployed on residential and commercial buildings, it is critical that PV not cause damage to the buildings nor harm the occupants. Many of the PV systems on buildings are of sufficiently high voltage (300 to 600 Volts dc) that they may present potential hazards. These PV systems must be safe in terms of mechanical damage (nothing falls on someone), shock hazard (no risk of electrical shock when touching an exposed circuit element), and fire (the modules neither cause nor promote a fire). The present safety standards (IEC 61730 and UL 1703) do a good job of providing for design rules and test requirements for mechanical, shock, and spread of flame dangers. However, neither standard addresses the issue of electrical arcing within a module that can cause a fire. To make PV modules, they must be designed, built, and installed with an emphasis on minimizing the potential for open circuits and ground faults. This paper provides recommendations on redundant connection designs, robust mounting methods, and changes to the safety standards to yield safer PV modules.

  20. The reliability of bypass diodes in PV modules

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.; Shiradkar, Narendra; Schneller, Eric; Gade, Vivek

    2013-09-01

    The operating conditions of bypass diodes in PV modules deployed in the field are considerably harsher than the conditions at which the diode manufacturers test the diodes. This has a potential to significantly reduce the operating life of bypass diodes and has raised concerns about the safety and reliability of PV modules as a whole. The study of modes and mechanisms of the failures encountered in bypass diodes used in PV modules can provide important information which would be useful to predict the module lifetime. This paper presents the review of the failure modes and mechanisms observed in bypass diodes and current work related to reliability testing of bypass diodes. The International PV Module Quality Assurance Task Force has recommended following four potential areas of research to understand the reliability issues of bypass diodes: Electrostatic Discharge, reverse bias thermal runaway testing, forward bias overheating and transition testing of forward bias to reverse bias. As a joint collaborative effort between Florida Solar Energy Center and Solar and Environmental Test Laboratory at Jabil Inc., laboratory testing of bypass diodes on the guidelines provided by the International PV Module Quality Assurance Task Force has been initiated. Preliminary results from this work are presented in this paper.

  1. Outdoor PV Module Degradation of Current-Voltage Parameters: Preprint

    SciTech Connect

    Smith, R. M.; Jordan, D. C.; Kurtz, S. R.

    2012-04-01

    Photovoltaic (PV) module degradation rate analysis quantifies the loss of PV power output over time and is useful for estimating the impact of degradation on the cost of energy. An understanding of the degradation of all current-voltage (I-V) parameters helps to determine the cause of the degradation and also gives useful information for the design of the system. This study reports on data collected from 12 distinct mono- and poly-crystalline modules deployed at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. Most modules investigated showed < 0.5%/year decrease in maximum power due to short-circuit current decline.

  2. Opportunities and Challenges for Power Electronics in PV Modules (Presentation)

    SciTech Connect

    Kurtz, S.; Deline, C.; Wohlgemuth, J.; Marion, B.; Granata, J.

    2011-02-01

    The presentation describes the value of adding DC converters and other power electronics to modules to improve their output even when shading or bad cells would otherwise decrease the module output. The presentation was part of a workshop sponsored by ARPA-E exploring the opportunities for power electronics to support PV applications.

  3. Baseline testing procedures for PV modules beyond the qualification testing

    NASA Astrophysics Data System (ADS)

    Schneller, Eric; Shiradkar, Narendra S.; Dhere, Neelkanth G.

    2013-09-01

    The qualification tests described in IEC 61215 for the c-Si PV modules are essentially pass/fail tests that assist in avoiding infant mortality. This paper reports on the baseline test procedure carried out on PV modules at Florida Solar Energy Center that go beyond the pass/fail criteria of the qualification tests and obtain information about the degradation modes and mechanisms. The importance and limitations of the various characterization techniques are described. Electroluminescence imaging has been used to detect and categorize the faults at the cell level. Indoor infrared imaging has been used to study the quality of electrical interconnects in the module. The infrared imaging carried out on the modules while they are undergoing outdoor exposure has provided information about the presence and distribution of hot spots in these modules. Conventionally, the insulation resistance tester has been used mostly for the dry and wet leakage test. In this study, the importance of the polarization index test and voltage excursion test are described. The use of these tests is essential to provide insight into the modes and mechanisms of degradation, during reliability and durability studies of PV modules. A predictive model for the service life of a PV module may be developed through the results obtained from these characterization techniques in conjunction with long-term exposure and accelerated lifetime tests.

  4. PV industry growth and module reliability in Thailand

    NASA Astrophysics Data System (ADS)

    Chenvidhya, Dhirayut; Seapan, Manit; Sangpongsanont, Yaowanee; Chenvidhya, Tanokkorn; Limsakul, Chamnan; Songprakorp, Roongrojana

    2015-09-01

    The PV applications in Thailand are now installed more than 1.2 GWp cumulatively. It is due to the National Renewable Energy Program and its targets. In the latest Alternative Energy Development Plan (AEDP), the PV electricity production target has increased from 2 GWp to 3 GWp. With this rapid growth, customers and manufacturers seek for module standard testing. So far over one thousands of PV modules per annum have been tested since 2012. The normal tests include type approval test according to TIS standard, acceptance test and testing for local standard development. For type test, the most module failure was found during damp heat test. For annual evaluation test, the power degradation and delamination of power was found between 0 to 6 percent from its nameplate after deployment of 0 to 5 years in the field. For thin-film module, the degradation and delamination was found in range of 0 to 13 percent (about 5 percent on average) from its nameplate for the modules in operation with less than 5 years. However, for the PV modules at the reference site on campus operated for 12 years, the power degradation was ranging from 10 to 15 percent. Therefore, a long term performance assessment needs to be considered to ensure the system reliability.

  5. Review of Artificial Abrasion Test Methods for PV Module Technology

    SciTech Connect

    Miller, David C.; Muller, Matt T.; Simpson, Lin J.

    2016-08-01

    This review is intended to identify the method or methods--and the basic details of those methods--that might be used to develop an artificial abrasion test. Methods used in the PV literature were compared with their closest implementation in existing standards. Also, meetings of the International PV Quality Assurance Task Force Task Group 12-3 (TG12-3, which is concerned with coated glass) were used to identify established test methods. Feedback from the group, which included many of the authors from the PV literature, included insights not explored within the literature itself. The combined experience and examples from the literature are intended to provide an assessment of the present industry practices and an informed path forward. Recommendations toward artificial abrasion test methods are then identified based on the experiences in the literature and feedback from the PV community. The review here is strictly focused on abrasion. Assessment methods, including optical performance (e.g., transmittance or reflectance), surface energy, and verification of chemical composition were not examined. Methods of artificially soiling PV modules or other specimens were not examined. The weathering of artificial or naturally soiled specimens (which may ultimately include combined temperature and humidity, thermal cycling and ultraviolet light) were also not examined. A sense of the purpose or application of an abrasion test method within the PV industry should, however, be evident from the literature.

  6. PV Cell and Module Calibrations at NREL

    SciTech Connect

    Emery, Keith

    2012-10-22

    NREL has equipment to measure any conceivable cell or module technology. The lack of standards for low concentration modules complicates matters. Spectrally adjustable simulators are critical for more than three junctions. NREL's 10-channel fiber optic simulator has shown that the light can be set for each junction within 1% of what it would be under the reference spectrum for up to a five-junction cell. Uncertainty in module simulators dominated by spatial nonuniformity for calibration labs. Manufacturers can mitigate this error by using matched reference modules instead of cells.

  7. Assessing the Causes of Encapsulant Delamination in PV Modules

    SciTech Connect

    Wohlgemuth, John H.; Hacke, Peter; Bosco, Nick; Miller, David C.; Kempe, Michael D.; Kurtz, Sarah R.

    2016-11-21

    Delamination of the encapsulant is one of the most prevalent PV module field failures. This paper will present examples of various types of delaminations that have been observed in the field. It will then discuss the development of accelerated stress tests designed to duplicate those field failures and thus provide tools for avoiding them in the future.

  8. Climatically Diverse Data Set for Flat-Plate PV Module Model Validations (Presentation)

    SciTech Connect

    Marion, B.

    2013-05-01

    Photovoltaic (PV) module I-V curves were measured at Florida, Colorado, and Oregon locations to provide data for the validation and development of models used for predicting the performance of PV modules.

  9. Methods for high-voltage bias testing of PV modules in hot and humid climate

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.; Pethe, Shirish A.; Kaul, Ashwani

    2011-09-01

    The accelerated tests currently carried out on PV modules reduce the infant mortality as well as improve the production techniques during the manufacture of PV modules. However, the accelerated tests do not completely duplicate the real world operating conditions of PV modules. Hence it is essential to deploy PV modules in the field for extended periods in order to estimate the degradation, if any, as well as to elucidate the degradation mechanisms. Moreover, PV modules should be tested by specially designed tests in harsh climates. At Florida Solar Energy Center (FSEC) high-voltage bias testing of PV modules was carried out in hot and humid climate with the individual modules biased at +/- 600 V. It was observed that the leakage currents flowing from the PV circuit to the ground is directly proportional to the bias voltage. PV systems with maximum voltage of 1000 V are installed in Europe and elsewhere which means higher leakage currents will be produced in the PV modules. Based on this fact and the earlier observations, high voltage bias testing of c-Si PV modules specially designed for high voltage operation was carried out in hot and humid climate with the individual modules biased at +/-1500 V at FSEC and higher. This paper provides results of high voltage bias testing of PV modules. The results indicate that the test can be considered as reliable metric in determination of the long term performance of PV modules.

  10. Planar holographic spectrum-splitting PV module design

    NASA Astrophysics Data System (ADS)

    Gordon, Michael; Zhang, Deming; Vorndran, Shelby; Russo, Juan M.; Luscombe, Christine K.; Shaheen, Sean E.; Kostuk, Raymond K.

    2012-10-01

    A design is presented for a planar spectrum-splitting photovoltaic (PV) module using Holographic Optical Elements (HOEs). A repeating array of HOEs diffracts portions of the solar spectrum onto different PV materials arranged in alternating strips. Several combinations of candidate PV materials are explored, and theoretical power conversion efficiency is quantified and compared for each case. The holograms are recorded in dichromated gelatin (DCG) film, an inexpensive material which is easily encapsulated directly into the panel. If desired, the holograms can focus the light to achieve concentration. The side-by-side split spectrum layout has advantages compared to a stacked tandem cell approach: since the cells are electrically isolated, current matching constraints are eliminated. Combinations of dissimilar types of cells are also possible: including crystalline, thin film, and organic PV cells. Configurations which yield significant efficiency gain using relatively inexpensive PV materials are of particular interest. A method used to optimize HOE design to work with a different candidate cells and different package aspect ratios is developed and presented. (Aspect ratio is width of the cell strips vs. the thickness of the panel) The relationship between aspect ratio and HOE performance properties is demonstrated. These properties include diffraction efficiency, spectral selectivity, tracking alignment sensitivity, and uniformity of cell illumination.

  11. All-AC, building integrated PV system for mass deployment of residential PV systems

    SciTech Connect

    Cammack, Kevin; Augenbraun, Joe; Sun, Dan

    2011-05-17

    Project Objective: Solar Red is developing novel PV installation methods and system designs that lower costs dramatically and allow seamless integration into the structure of any sloped roof using existing construction tools and processes. The overall objective of this project is to address the greatest barriers to massive adoption of residential and small commercial rooftop solar – scalability of installation and total cost of ownership - by moving Solar Red’s snap-in/snap-out PV installation method from the pre-prototype design phase to the development and construction of a deployed prototype system. Financial Summary: Funded through ARRA, DOE and Match Funding Original Project Budget: $229,310 o DOE/ARRA Funding: $150,000 o Match Funding: $79,310 Actual Cost: $216,598 o DOE/ARRA Funding: $150,000 o Match Funding: $120,087 Project Summary: Develop snap-in/snap-out mounting system for low-cost, thin-film solar panels – Lower installation cost – Lower sales costs – Lower training/expertise barriers

  12. Final PV module degradation-analysis report

    SciTech Connect

    Themelis, M P

    1982-06-01

    Visual and electrical degradation analyses were performed on 47 modules from: the Natural Bridges National Monument (NBNM) in Utah; Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts; and the University of Nebraska at Mead, Nebraska. Such problems as discoloration, cracking, scratches, and electrical degradation were detected. (LEW)

  13. Analysis of Irradiance Models for Bifacial PV Modules

    SciTech Connect

    Hansen, Clifford W.; Stein, Joshua S.; Deline, Chris; MacAlpine, Sara; Marion, Bill; Asgharzadeh, Amir; Toor, Fatima

    2016-11-21

    We describe and compare two methods for modeling irradiance on the back surface of rack-mounted bifacial PV modules: view factor models and ray-tracing simulations. For each method we formulate one or more models and compare each model with irradiance measurements and short circuit current for a bifacial module mounted a fixed tilt rack with three other similarly sized modules. Our analysis illustrates the computational requirements of the different methods and provides insight into their practical applications. We find a level of consistency among the models which indicates that consistent models may be obtained by parameter calibrations.

  14. The reliability and stability of multijunction amorphous silicon PV modules

    SciTech Connect

    Carlson, D.E.

    1995-11-01

    Solarex is developing a manufacturing process for the commercial production of 8 ft{sup 2} multijunction amorphous silicon (a-Si) PV modules starting in 1996. The device structure used in these multijunction modules is: glass/textured tin oxide/p-i-n/p-i-n/ZnO/Al/EVA/Tedlar where the back junction of the tandem structure contains an amorphous silicon germanium alloy. As an interim step, 4 ft{sup 2} multijunction modules have been fabricated in a pilot production mode over the last several months. The distribution of initial conversion efficiencies for an engineering run of 67 modules (4 ft{sup 2}) is shown. Measurements recently performed at NREL indicate that the actual efficiencies are about 5% higher than those shown, and thus exhibit an average initial conversion efficiency of about 9.5%. The data indicates that the process is relatively robust since there were no modules with initial efficiencies less than 7.5%.

  15. Detecting loss mechanisms of c-Si PV modules in-situ I-V measurement

    NASA Astrophysics Data System (ADS)

    Guo, Siyu; Schneller, Eric; Walters, Joe; Davis, Kristopher O.; Schoenfeld, Winston V.

    2016-09-01

    PV module reliability is alsways an important issue for PV industry. In an outdoor PV system, PV modules suffer from degradation due to different factors. It is then very important to determine the loss mechanisms of a PV module and making improvement based on this. It is found in this work that due to mismatch effect, using fitting method to extract I-V characteristics might not be well applied on a PV module, especially when it has non-uniform degradation problem. This work proposes a method to accurately quantify the power loss of PV modules due to different degradation mechanisms, including series resistance (Rs) loss, non-uniform shunting loss and number of shunted cells, uniform shunting loss, uniform current loss, non-uniform current (mismatch) loss, recombination current (J01 and J02) losses of a PV module. All required input information are the measured current-voltage (I-V) curves and short circuit current- open circuit voltage (Isc-Voc) of PV module initial state and final state. The method is first applied to a simulated PV module with various degradation problems. Power loss due to each loss mechanism for the simulated PV module is then extracted using the proposed method and a pie chart can be generated. Comparing with the actual power loss on each loss mechanism, the method proposed in this work is proved to be very accurate. The method is then further applied to a degradated PV module istalled in an outdoor PV system. The power loss on series resistance, shunting and current mismatch are effectively identified and the number of shunted cells is accurately calculated. In the real application, this method can be used in both indoor and outdoor characterization, which can be very beneficial for PV degradation analysis of PV modules and systems.

  16. A modeling framework for potential induced degradation in PV modules

    NASA Astrophysics Data System (ADS)

    Bermel, Peter; Asadpour, Reza; Zhou, Chao; Alam, Muhammad A.

    2015-09-01

    Major sources of performance degradation and failure in glass-encapsulated PV modules include moisture-induced gridline corrosion, potential-induced degradation (PID) of the cell, and stress-induced busbar delamination. Recent studies have shown that PV modules operating in damp heat at -600 V are vulnerable to large amounts of degradation, potentially up to 90% of the original power output within 200 hours. To improve module reliability and restore power production in the presence of PID and other failure mechanisms, a fundamental rethinking of accelerated testing is needed. This in turn will require an improved understanding of technology choices made early in development that impact failures later. In this work, we present an integrated approach of modeling, characterization, and validation to address these problems. A hierarchical modeling framework will allows us to clarify the mechanisms of corrosion, PID, and delamination. We will employ a physics-based compact model of the cell, topology of the electrode interconnection, geometry of the packaging stack, and environmental operating conditions to predict the current, voltage, temperature, and stress distributions in PV modules correlated with the acceleration of specific degradation modes. A self-consistent solution will capture the essential complexity of the technology-specific acceleration of PID and other degradation mechanisms as a function of illumination, ambient temperature, and relative humidity. Initial results from our model include specific lifetime predictions suitable for direct comparison with indoor and outdoor experiments, which are qualitatively validated by prior work. This approach could play a significant role in developing novel accelerated lifetime tests.

  17. Approaches to improving energy yield from PV modules

    NASA Astrophysics Data System (ADS)

    Jaus, Joachim; Duell, Matthias; Eckert, Johannes; Adurodija, Frederick O.; Li, Biao; Mickiewicz, Rafal A.; Doble, Dan M.

    2010-08-01

    PV modules were fabricated that incorporated various methods to increase the amount of light which is ultimately transmitted to the solar cell in order to improve energy yield. The techniques employed included diffuse scattering and reflection to minimize shading losses, as well as using structured glass to increase the probability of incident light capture. In the first technology, a laser is used to create a scattering pattern on the front-side glass of the module. This pattern directed light away from the bus bars and grid fingers, resulting in an increase in short circuit current (ISC) of up to 3.3%. In the second technology, the bus wires were coated with a diffuse reflective coating. A part of the incident sunlight is reflected from this coating at such angles that internal reflection at the front surface of the front-side glass occurs. The light is reflected back to the active area of the solar cell and contributes to the generated photocurrent resulting in an average increase of 0.9% in ISC. Finally, four different types of commercially available structured glass were investigated: grooves, pyramids, inverted pyramids, and a very lightly textured glass with only 5% increased surface area. Results showed an increase in ISC of up to 3.2% for pyramid structures using normally incident light, with the effect increasing at higher angles of incidence. The results demonstrated the possibility of improving PV module energy yield by taking advantage of basic optical principles and straightforward processing methods.

  18. New Barrier Coating Materials for PV Module Backsheets: Preprint

    SciTech Connect

    Barber, G. D.; Jorgensen, G. J.; Terwilliger, K.; Glick, S. H.; Pern, J.; McMahon, T. J.

    2002-05-01

    This conference paper describes the high moisture barrier high resistivity coatings on polyethylene terepthalate (PET) have been fabricated and characterized for use in PV module back sheet applications. These thin film barriers exhibit water vapor transmission rates (WVTR) as low as 0.1 g/m2-day at 37.8 C and have shown excellent adhesion (> 10 N/mm) to both ethylene vinyl acetate (EVA) and PET even after filtered xenon arc lamp UV exposure. The WVTR and adhesion values for this construction are compared to and shown to be superior to candidate polymeric backsheet materials.

  19. Rating PV Power and Energy: Cell, Module, and System Measurements

    SciTech Connect

    Emery, Keith

    2016-06-02

    A summary of key points related to research-level measurements of current vs. voltage measurement theory including basic PV operation, equivalent circuit, and concept of spectral error; PV power performance including PV irradiance sensors, simulators and commercial and generic I-V systems; PV measurement artifacts, intercomparisons, and alternative rating methods.

  20. Transparent building-integrated PV modules. Phase 1: Comprehensive report

    SciTech Connect

    1998-09-28

    This Comprehensive Report encompasses the activities that have been undertaken by Kiss + Cathcart, Architects, in conjunction with Energy Photovoltaics, Incorporated (EPV), to develop a flexible patterning system for thin-film photovoltaic (PV) modules for building applications. There are two basic methods for increasing transparency/light transmission by means of patterning the PV film: widening existing scribe lines, or scribing a second series of lines perpendicular to the first. These methods can yield essentially any degree of light transmission, but both result in visible patterns of light and dark on the panel surface. A third proposed method is to burn a grid of dots through the films, independent of the normal cell scribing. This method has the potential to produce a light-transmitting panel with no visible pattern. Ornamental patterns at larger scales can be created using combinations of these techniques. Kiss + Cathcart, Architects, in conjunction with EPV are currently developing a complementary process for the large-scale lamination of thin-film PVs, which enables building integrated (BIPV) modules to be produced in sizes up to 48 in. x 96 in. Flexible laser patterning will be used for three main purposes, all intended to broaden the appeal of the product to the building sector: To create semitransparent thin-film modules for skylights, and in some applications, for vision glazing.; to create patterns for ornamental effects. This application is similar to fritted glass, which is used for shading, visual screening, graphics, and other purposes; and to allow BIPV modules to be fabricated in various sizes and shapes with maximum control over electrical characteristics.

  1. NREL PV Module Reliability and Performance R&D Status and Accomplishments

    SciTech Connect

    Osterwald, C. R.

    2005-01-01

    This paper presents a brief overview of the status and accomplishments during Fiscal Year (FY)2004 of the Photovoltaic (PV) Module Reliability and Performance R&D Subtask, which is part of the PV Module Reliability R&D Project (a joint NREL-Sandia project).

  2. Packaging Materials and Design for Improved PV Module Reliability

    SciTech Connect

    Jorgensen, G.; Terwilliger, K.; Kempe, M.; Pern, J.; Glick, S.; del Cueto, J.; Kennedy, C.; McMahon, T.

    2005-01-01

    A number of candidate alternative encapsulant and soft backsheet materials have been evaluated in terms of their suitability for photovoltaic (PV) module packaging applications. Relevant properties, including peel strength as a function of damp heat exposure and permeability, have been measured. Based on these tests, promising new encapsulants with adhesion-promoting primers have been identified that result in improved properties. Test results for backsheets provided by industry and prepared at the National Renewable Energy Laboratory (NREL) have suggested strategies to achieve significantly improved products. The ability of glass/glass and glass/breathable backsheet constructions laminated with various encapsulant and/or edge seal materials to protect thin-film aluminum coatings deposited onto glass substrates was assessed. Glass/glass laminate constructions can trap harmful compounds that catalyze moisture-driven corrosion of the aluminum. Constructions with breathable backsheets allow higher rates of moisture ingress, but also allow egress of deleterious substances that can result in decreased corrosion.

  3. A hybrid life-cycle inventory for multi-crystalline silicon PV module manufacturing in China

    NASA Astrophysics Data System (ADS)

    Yao, Yuan; Chang, Yuan; Masanet, Eric

    2014-11-01

    China is the world’s largest manufacturer of multi-crystalline silicon photovoltaic (mc-Si PV) modules, which is a key enabling technology in the global transition to renewable electric power systems. This study presents a hybrid life-cycle inventory (LCI) of Chinese mc-Si PV modules, which fills a critical knowledge gap on the environmental implications of mc-Si PV module manufacturing in China. The hybrid LCI approach combines process-based LCI data for module and poly-silicon manufacturing plants with a 2007 China IO-LCI model for production of raw material and fuel inputs to estimate ‘cradle to gate’ primary energy use, water consumption, and major air pollutant emissions (carbon dioxide, methane, sulfur dioxide, nitrous oxide, and nitrogen oxides). Results suggest that mc-Si PV modules from China may come with higher environmental burdens that one might estimate if one were using LCI results for mc-Si PV modules manufactured elsewhere. These higher burdens can be reasonably explained by the efficiency differences in China’s poly-silicon manufacturing processes, the country’s dependence on highly polluting coal-fired electricity, and the expanded system boundaries associated with the hybrid LCI modeling framework. The results should be useful for establishing more conservative ranges on the potential ‘cradle to gate’ impacts of mc-Si PV module manufacturing for more robust LCAs of PV deployment scenarios.

  4. User's Manual for Data for Validating Models for PV Module Performance

    SciTech Connect

    Marion, W.; Anderberg, A.; Deline, C.; Glick, S.; Muller, M.; Perrin, G.; Rodriguez, J.; Rummel, S.; Terwilliger, K.; Silverman, T. J.

    2014-04-01

    This user's manual describes performance data measured for flat-plate photovoltaic (PV) modules installed in Cocoa, Florida, Eugene, Oregon, and Golden, Colorado. The data include PV module current-voltage curves and associated meteorological data for approximately one-year periods. These publicly available data are intended to facilitate the validation of existing models for predicting the performance of PV modules, and for the development of new and improved models. For comparing different modeling approaches, using these public data will provide transparency and more meaningful comparisons of the relative benefits.

  5. Passive thermal regulation of flat PV modules by coupling the mechanisms of evaporative and fin cooling

    NASA Astrophysics Data System (ADS)

    Chandrasekar, M.; Senthilkumar, T.

    2016-07-01

    A passive thermal regulation technique with fins in conjunction with cotton wicks is developed in the present work for controlling the temperature of PV module during its operation. Experiments were conducted with the developed technique in the location of Tiruchirappalli (78.6°E and 10.8°N), Tamil Nadu, India with flat 25 Wp PV module and its viability was confirmed. The PV module temperature got reduced by 12 % while the electrical yield is increased by 14 % with the help of the developed cooling system. Basic energy balance equation applicable for PV module was used to evaluate the module temperatures and a fair agreement was obtained between the theoretical and experimental values for the cases of with cooling and without cooling.

  6. Technology and Climate Trends in PV Module Degradation: Preprint

    SciTech Connect

    Jordan, D. C.; Wohlgemuth, J. H.; Kurtz, S. R.

    2012-10-01

    To sustain the commercial success of photovoltaic (PV) technology it is vital to know how power output decreases with time. Unfortunately, it can take years to accurately measure the long-term degradation of new products, but past experience on older products can provide a basis for prediction of degradation rates of new products. An extensive search resulted in more than 2000 reported degradation rates with more than 1100 reported rates that include some or all IV parameters. In this paper we discuss how the details of the degradation data give clues about the degradation mechanisms and how they depend on technology and climate zones as well as how they affect current and voltage differently. The largest contributor to maximum power decline for crystalline Si technologies is short circuit current (or maximum current) degradation and to a lesser degree loss in fill factor. Thin-film technologies are characterized by a much higher contribution from fill factor particularly for humid climates. Crystalline Si technologies in hot & humid climates also display a higher probability to show a mixture of losses (not just short circuit current losses) compared to other climates. The distribution for the module I-V parameters (electrical mismatch) was found to change with field exposure. The distributions not only widened but also developed a tail at the lower end, skewing the distribution.

  7. Technology and Climate Trends in PV Module Degradation (Presentation)

    SciTech Connect

    Jordan, D.; Wohlgemuth, J.; Kurtz, S.

    2012-10-01

    To sustain the commercial success of photovoltaic (PV) technology it is vital to know how power output decreases with time. Unfortunately, it can take years to accurately measure the long-term degradation of new products, but past experience on older products can provide a basis for prediction of degradation rates of new products. An extensive search resulted in more than 2000 reported degradation rates with more than 1100 reported rates that include some or all IV parameters. In this presentation we discuss how the details of the degradation data give clues about the degradation mechanisms and how they depend on technology and climate zones as well as how they affect current and voltage differently. The largest contributor to maximum power decline for crystalline Si technologies is short circuit current (or maximum current) degradation and to a lesser degree loss in fill factor. Thin-film technologies are characterized by a much higher contribution from fill factor particularly for humid climates. Crystalline Si technologies in hot & humid climates also display a higher probability to show a mixture of losses (not just short circuit current losses) compared to other climates. The distribution for the module I-V parameters (electrical mismatch) was found to change with field exposure. The distributions not only widened but also developed a tail at the lower end, skewing the distribution.

  8. Introduction of Break-Out Session at the International PV Module Quality Assurance Forum (Presentation)

    SciTech Connect

    Kurtz, S.; Wohlgemuth, J.; Yamamichi, M.; Sample, T.

    2011-07-01

    This presentation outlines review requirements for quality assurance (QA) rating systems, logical design of QA systems, and specific tasks for break-out session 1 of the 2011 International PV Module Quality Assurance Forum.

  9. Analysis of Photovoltaic (PV) Module during Partial Shading based on Simplified Two-Diode Model

    NASA Astrophysics Data System (ADS)

    Chitti Babu, B.; Gurjar, Suresh; Meher, Ashish

    2015-02-01

    Generally, the characteristics of photovoltaic (PV) array are largely affected by solar temperature, solar irradiance, shading patterns, array configuration and location of shading modules. Partial shading is due to moving clouds and shadows of nearby obstacles and can cause a significant degradation in the output of PV system. Hence, the characteristics of PV array get more multifaceted with multiple peaks. The ultimate aim of the paper is to analyze the performance of PV module during such adverse condition based on simplified two-diode model. To reduce the computational time, the simplified two-diode model has a photocurrent source in parallel with two ideal diodes. Only four parameters are required to be calculated from datasheet in order to simulate the model. Moreover, the performance of PV array is evaluated at different shaded patterns and it is found that the model has less computational time and gives accurate results.

  10. SMART empirical approaches for predicting field performance of PV modules from results of reliability tests

    NASA Astrophysics Data System (ADS)

    Hardikar, Kedar Y.; Liu, Bill J. J.; Bheemreddy, Venkata

    2016-09-01

    Gaining an understanding of degradation mechanisms and their characterization are critical in developing relevant accelerated tests to ensure PV module performance warranty over a typical lifetime of 25 years. As newer technologies are adapted for PV, including new PV cell technologies, new packaging materials, and newer product designs, the availability of field data over extended periods of time for product performance assessment cannot be expected within the typical timeframe for business decisions. In this work, to enable product design decisions and product performance assessment for PV modules utilizing newer technologies, Simulation and Mechanism based Accelerated Reliability Testing (SMART) methodology and empirical approaches to predict field performance from accelerated test results are presented. The method is demonstrated for field life assessment of flexible PV modules based on degradation mechanisms observed in two accelerated tests, namely, Damp Heat and Thermal Cycling. The method is based on design of accelerated testing scheme with the intent to develop relevant acceleration factor models. The acceleration factor model is validated by extensive reliability testing under different conditions going beyond the established certification standards. Once the acceleration factor model is validated for the test matrix a modeling scheme is developed to predict field performance from results of accelerated testing for particular failure modes of interest. Further refinement of the model can continue as more field data becomes available. While the demonstration of the method in this work is for thin film flexible PV modules, the framework and methodology can be adapted to other PV products.

  11. Development of a Visual Inspection Data Collection Tool for Evaluation of Fielded PV Module Condition

    SciTech Connect

    Packard, C. E.; Wohlgemuth, J. H.; Kurtz, S. R.

    2012-08-01

    A visual inspection data collection tool for the evaluation of fielded photovoltaic (PV) modules has been developed to facilitate describing the condition of PV modules with regard to field performance. The proposed data collection tool consists of 14 sections, each documenting the appearance or properties of a part of the module. This report instructs on how to use the collection tool and defines each attribute to ensure reliable and valid data collection. This tool has been evaluated through the inspection of over 60 PV modules produced by more than 20 manufacturers and fielded at two different sites for varying periods of time. Aggregated data from such a single data collection tool has the potential to enable longitudinal studies of module condition over time, technology evolution, and field location for the enhancement of module reliability models.

  12. Standards for PV Modules and Components -- Recent Developments and Challenges: Preprint

    SciTech Connect

    Wohlgemuth, J. H.

    2012-10-01

    International standards play an important role in the Photovoltaic industry. Since PV is such a global industry it is critical that PV products be measured and qualified the same way everywhere in the world. IEC TC82 has developed and published a number of module and component measurement and qualification standards. These are continually being updated to take advantage of new techniques and equipment as well as better understanding of test requirements. Standards presently being updated include the third edition of IEC 61215, Crystalline Silicon Qualification and the second edition of IEC 61730, PV Module Safety Requirements. New standards under development include qualification of junction boxes, connectors, PV cables, and module integrated electronics as well as for testing the packaging used during transport of modules. After many years of effort, a draft standard on Module Energy Rating should be circulated for review soon. New activities have been undertaken to develop standards for the materials within a module and to develop tests that evaluate modules for wear-out in the field (International PV Module QA Task Force). This paper will discuss these efforts and indicate how the audience can participate in development of international standards.

  13. Spectrum sensitivity, energy yield, and revenue prediction of PV and CPV modules

    SciTech Connect

    Kinsey, Geoffrey S.

    2015-09-28

    Impact on module performance of spectral irradiance variation has been determined for III-V multijunctions compared against the four most common flat-plate module types (cadmium telluride, multicrystalline silicon, copper indium gallium selenide, and monocrystalline silicon. Hour-by-hour representative spectra were generated using atmospheric variables for Albuquerque, New Mexico, USA. Convolution with published values for external quantum efficiency gave the predicted current output. When combined with specifications of commercial PV modules, energy yield and revenue were predicted. This approach provides a means for optimizing PV module design based on various site-specific temporal variables.

  14. The vital role of manufacturing quality in the reliability of PV modules

    NASA Astrophysics Data System (ADS)

    Rusch, Peter

    2014-10-01

    The influence of manufacturing quality on the reliability of PV modules coming out of today's factories has been, and is still, under estimated among investors and buyers. The main reason is perception. Contrary to popular belief, PV modules are not a commodity. Module quality does differ among module brands. Certification alone does not guarantee the quality or reliability of a module. Cost reductions in manufacturing have unequivocally affected module quality. And the use of new, cheaper materials has had a measureable impact on module reliability. The need for meaningful manufacturing quality standards has been understood by the leading technical institutions and important industry players. The fact that most leading PV panel manufacturers have been certified according to ISO 9001 has led to some level of improvement and higher effectiveness. The new ISO 9001 PV QMS standards will be a major step in providing a tool to assess PV manufacturers' quality management systems. The current lack of sufficient standards has still got a negative influence on the quality of modules being installed today. Today every manufacturer builds their modules in their own way with little standardization or adherence to quality processes and methods, which are commonplace in other manufacturing industries. Although photovoltaic technology is to a great extent mature, the way modules are being produced has changed significantly over the past few years and it continues to change at a rapid pace. Investors, financiers and lenders stand the most to gain from PV systems over the long-term, but also the most to lose. Investors, developers, EPC, O&M and solar asset management companies must all manage manufacturing quality more proactively or they will face unexpected risks and failures down the road. Manufacturing quality deserves more transparency and attention, as it is a major driver of module performance and reliability. This paper will explain the benefits of good manufacturing

  15. Detection and characterisation of delamination in PV modules by active infrared thermography

    NASA Astrophysics Data System (ADS)

    Sinha, A.; Sastry, O. S.; Gupta, R.

    2016-01-01

    The paper presents a fast and efficient method for the detection and characterisation of delamination in photovoltaic (PV) modules by using active infrared thermography approach. A discrete part of PV module was irradiated by step heating and its thermal image sequence was used to detect and analyse delamination. Different types of heating source for thermal excitation for this application have been studied. An electro-thermal model was developed to simulate the active thermography approach for the characterisation of delamination in PV module by equivalent resistance-capacitance (RC) network using a circuit simulator. This simulation approach was used to estimate the extent of delamination in the module and to determine the optimum parameters for the characterisation of delamination. Different applications based on front and backsides of heating the module were also proposed in this paper. The proposed method has the potential to be employed for the quality check of PV modules during inline production as well as for the predictive maintenance of outdoor PV plants.

  16. Performances and failure of field-aged PV modules operating in Saharan region of Algeria

    NASA Astrophysics Data System (ADS)

    Sadok, M.; Benyoucef, B.; Othmani, M.; Mehdaoui, A.

    2016-07-01

    This article deals with behaviour of PV modules, of different technologies and manufacturers, exposed for long periods in Saharan region of Algeria. These modules are exposed in Adrar in the south-western part of Algeria. The study uses experimental I-V curves of PV modules for determining their performances. The datasheet information of modules will be useful in determination of degradation rates of the modules. Three types of modules have been tested: Photowatt (PWX 500), UDTS-50 and Isofoton (I-75 and I-100 serials). Results showed that Isofoton I-100 modules present the highest degradation rate while the lowest degradation rate was reached with I-75 serial. However, these rates tallies with other studies. The visual inspection of the modules has revealed various kinds of failures and defects responsible of performances drop (EVA browning, delamination, burn marks,…).

  17. High Performance Packaging Solutions for Low Cost, Reliable PV Modules: Final Subcontract Report, 26 May 2005 - 30 November 2008

    SciTech Connect

    Keotla, B. M.; Marinik, B. J.

    2009-06-01

    During this research effort, Dow Corning Corporation has addressed the PV manufacturing goals of: (i) improving PV manufacturing processes and equipment; (ii) accelerating manufacturing cost reductions of PV modules; (iii) increasing commercial product performance and reliability; and (iv) scaling up U.S. manufacturing capacity.

  18. PV_LIB Toolbox v. 1.3

    SciTech Connect

    2015-12-09

    PV_LIB comprises a library of Matlab? code for modeling photovoltaic (PV) systems. Included are functions to compute solar position and to estimate irradiance in the PV system’s plane of array, cell temperature, PV module electrical output, and conversion from DC to AC power. Also included are functions that aid in determining parameters for module performance models from module characterization testing. PV_LIB is open source code primarily intended for research and academic purposes. All algorithms are documented in openly available literature with the appropriate references included in comments within the code.

  19. Development of flame retardant PV module encapsulants: Volume 1. Final report

    SciTech Connect

    Galica, J.P.

    1998-06-01

    This Phase 1 final report covers the work performed by Springborn Testing and Research, Inc., for the period October 1, 1997 to June 30, 1998 under the Department of Energy Cooperative Agreement Number DE-FC36-97GO10255, entitled Development of Flame Retardant PV Module Encapsulants. While use of roof-mounted arrays has always been an attractive means of deploying PV, only within recent years have such building integrated concepts (BIPV) found renewed interest among module makers and end-users. Prior to building integrated and rooftop applications, flammability requirements for modules have not been a great industry concern. However, with growing interest in BIPV and the requirement for building code requirements for commercial and industrial structures, flammability issues have become a barrier to entry for many module constructions into this potentially huge domestic market for PV. The overall goal of the 3 phase PV BONUS two project is to develop and commercialize a line of fire retardant encapsulation materials to serve the emerging building integrated and building mounted PV market. The objectives of the Phase 1 effort are limited to concept development and business planning activities.

  20. Bottom-Up Cost Analysis of a High Concentration PV Module

    SciTech Connect

    Horowitz, Kelsey A. W.; Woodhouse, Michael; Lee, Hohyun; Smestad, Greg P.

    2016-03-31

    We present a bottom-up model of III-V multi-junction cells, as well as a high concentration PV (HCPV) module. We calculate $0.59/W(DC) manufacturing costs for our model HCPV module design with today's capabilities, and find that reducing cell costs and increasing module efficiency offer the most promising paths for future cost reductions. Cell costs could be significantly reduced via substrate reuse and improved manufacturing yields.

  1. Launch packaging options for the PV power module cargo element. [for space station power supplies

    NASA Technical Reports Server (NTRS)

    Hoberecht, Mark A.; Vogt, Scott T.

    1989-01-01

    NASA recently embarked on the Space Station Freedom program, which will utilize the Shuttle Orbiter for transportation to orbit. Each flight is unique in terms of the hardware that is manifested and the method by which it is integrated to form viable cargo elements. Various constraints determine the packaging options for the three PV power module combined assemblies. Several packaging options for the PV power module cargo element are presented. These options are discussed in terms of their impact on the overall flight hardware manifest as determined by the various constraints.

  2. Specific energy yield comparison between crystalline silicon and amorphous silicon based PV modules

    NASA Astrophysics Data System (ADS)

    Ferenczi, Toby; Stern, Omar; Hartung, Marianne; Mueggenburg, Eike; Lynass, Mark; Bernal, Eva; Mayer, Oliver; Zettl, Marcus

    2009-08-01

    As emerging thin-film PV technologies continue to penetrate the market and the number of utility scale installations substantially increase, detailed understanding of the performance of the various PV technologies becomes more important. An accurate database for each technology is essential for precise project planning, energy yield prediction and project financing. However recent publications showed that it is very difficult to get accurate and reliable performance data of theses technologies. This paper evaluates previously reported claims the amorphous silicon based PV modules have a higher annual energy yield compared to crystalline silicon modules relative to their rated performance. In order to acquire a detailed understanding of this effect, outdoor module tests were performed at GE Global Research Center in Munich. In this study we examine closely two of the five reported factors that contribute to enhanced energy yield of amorphous silicon modules. We find evidence to support each of these factors and evaluate their relative significance. We discuss aspects for improvement in how PV modules are sold and identify areas for further study further study.

  3. A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions.

    PubMed

    Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C

    2015-07-29

    This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper.

  4. A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions

    PubMed Central

    Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C.

    2015-01-01

    This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper. PMID:26230694

  5. Present and Future Silver Cost Component in Crystalline Silicon PV Module Manufacturing

    SciTech Connect

    Redlinger, Michael; Eggert, Roderick G.; Woodhouse, Michael

    2016-03-01

    The purpose of this paper is to determine how increased c-Si PV module production might affect future silver demand and prices, as well as the impacts on total c-Si module manufacturing costs. To evaluate how PV's changing demand for silver might affect future silver prices, and the impact in terms of manufacturing costs, some scenarios of silver's contribution to c-Si PV cell manufacturing costs are compiled on the basis of projected changes in demand and price as a result of changes in material intensity. The analysis indicates that an expansion of c-Si production from 55GW/year to 250GW/year results in a 0.05-0.7 cent/W increase in manufacturing costs because of higher silver prices.

  6. Modeling Current Transfer from PV Modules Based on Meteorological Data

    SciTech Connect

    Hacke, Peter; Smith, Ryan; Kurtz, Sarah; Jordan, Dirk; Wohlgemuth, John

    2016-11-21

    Current transferred from the active cell circuit to ground in modules undergoing potential-induced degradation (PID) stress is analyzed with respect to meteorological data. Duration and coulombs transferred as a function of whether the module is wet (from dew or rain) or the extent of uncondensed surface humidity are quantified based on meteorological indicators. With this, functions predicting the mode and rate of coulomb transfer are developed for use in estimating the relative PID stress associated with temperature, moisture, and system voltage in any climate. Current transfer in a framed crystalline silicon module is relatively high when there is no condensed water on the module, whereas current transfer in a thin-film module held by edge clips is not, and displays a greater fraction of coulombs transferred when wet compared to the framed module in the natural environment.

  7. Hot spot susceptibility and testing of PV modules

    NASA Astrophysics Data System (ADS)

    Molenbroek, E.; Waddington, D. W.; Emery, K. A.

    To probe the sensitivity for localized heating of commercial amorphous silicon and crystalline modules, several intrusive and nonintrusive experiments were performed. In the intrusive experiments, each cell in several commercial amorphous silicon modules was evaluated separately and in groups for localized heating effects. Damage in amorphous silicon modules occurred under reverse-bias conditions in the dark above a 5-20 mA/sq cm cell current density at the interconnection between cells. Shading can cause a larger temperature rise than current mismatch. For the monolithic amorphous silicon modules investigated, the current mismatch between each cell was substantial, but the temperature rise was negligible because of the rather low shunt resistance.

  8. A versatile PV module simulation model based on PSI/e

    SciTech Connect

    Lawrance, W.B.; Wichert, B. )

    1994-02-01

    A novel approach to the simulation of PV modules is described. The method uses the software package PSI/e developed by the Delft University of Technology. Using PSI/e, the array equations are solved for a variety of operating conditions. The results are verified by comparison with measured data and the manufacturers figures for a BP164 solar panel.

  9. Use of Pyranometers to Estimate PV Module Degradation Rates in the Field

    SciTech Connect

    Vignola, Frank; Peterson, Josh; Kessler, Rich; Mavromatakis, Fotis; Dooraghi, Mike; Sengupta, Manajit

    2016-11-21

    Methodology is described that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is discussed. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.

  10. Use of Pyranometers to Estimate PV Module Degradation Rates in the Field: Preprint

    SciTech Connect

    Vignola, Frank; Peterson, Josh; Kessler, Rich; Mavromatakis, Fotis; Dooraghi, Mike; Sengupta, Manajit

    2016-08-01

    This paper describes a methodology that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is illustrated. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.

  11. Use of Pyranometers to Estimate PV Module Degradation Rates in the Field

    SciTech Connect

    Vignola, Frank; Peterson, Josh; Kessler, Rich; Mavromatakis, Fotis; Dooraghi, Mike; Sengupta, Manajit

    2016-06-05

    This poster provides an overview of a methodology that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is illustrated. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.

  12. Understanding the Temperature and Humidity Environment Inside a PV Module (Presentation)

    SciTech Connect

    Kempe, M.

    2013-06-01

    This presentation addresses moisture-driven degradation processes in PV modules and the conditions to use for accelerated stress testing. Here we show that by choosing humidity conditions that more closely match the use environment, one can minimize the uncertainty associated with moisture induced degradation modes.

  13. Evaluation of modern IGBT-modules for hard-switched AC/DC/AC converters

    SciTech Connect

    Blaabjerg, F.; Pedersen, J.K.; Jaeger, U.

    1995-12-31

    The development of IGBT devices is still producing faster devices with lower losses. The applications become more advanced like a complete hard-switched AC/DC/AC converter with almost clean input current and regenerating capabilities. This paper will first focus on a detailed characterization and comparison of eight different IGBT-modules representing state-of-the-art for both PT and NPT technologies. The voltage level of the devices is 1,200V and 1,600V/1,700V. The characterization is done on an advanced measurement system which is briefly described. The characterization is based on static and dynamic tests for both IGBT and the diodes in the IGBT-modules at a junction temperature at 125 C. The comparison is first done directly based on conduction losses and switching losses, and later the measurements are used in a loss model for a complete AC/DC/AC converter application. In the AC/DC/AC converter the power losses are modelled, and different operating conditions are compared like different voltage levels in the DC-link. It is concluded dependent on operation conditions different devices will be preferable, but the high voltage devices have the highest losses even at a high operating voltage.

  14. When PV modules are becoming real building elements: White solar module, a revolution for BIPV (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Perret-Aebi, Laure-Emmanuelle; Escarré, Jordi; Li, Heng-Yu; Sansonnens, Laurent; Galliano, Federico; Cattaneo, Gianluca; Heinstein, Patrick; Nicolay, Sylvain; Bailat, Julien; Eberhard, Sébastien; Ballif, Christophe

    2015-09-01

    The use of photovoltaic (PV) is not anymore an option but a real need in the construction of nearly zero energy buildings. To date, the lack of PV products specifically designed for building integration, considering aesthetics and architectural aspects, is one important limiting factor allowing a massive deployment of PV in the built environment. Architects are continuously asking for new solutions to customize the colour of PV elements to better integrate them into the building skin. Among these colours, white is especially attractive as it is widely used in architecture for its elegance, versatility and fresh look. Until now, white solar modules were not considered to be an option and even never been though to be a technological possibility. Nonetheless, CSEM recently developed a new technology to make white solar modules a reality. Furthermore, the new Swiss company called Solaxess is now working on the industrialisation of this very innovative technology and the first products are expecting to be on the market at the end of 2015. The technology is based on the combination of two different elements: a solar cell able to convert solar infrared light into electricity and a selective filter which reflects and diffuse the whole visible spectrum. Any PV technology based on crystalline silicon can be used as they have a good response in the infrared. Approximately 55% of the current generated under standard test conditions comes from the infrared leading to conversion efficiencies above 11%. We will demonstrate, that thanks to this very innovative technology PV modules can become attractive and real active building elements and therefore meets the requirements of any future energy management through advanced building skins.

  15. Real-Time and Accelerated Solar Weathering of Commercial PV Modules: Preprint

    SciTech Connect

    Osterwald, C. R.; Pruett, J.; Myers, D. R.; Rummel, S.; Anderberg, A.; Ottoson, L.; Basso, T.

    2001-10-01

    Presented at the 2001 NCPV Program Review Meeting: We report the observed degradation in 6 different types of PV modules as a function of total UV exposure and give a number of recommendations for future weathering tests. Since 1997, using existing ASTM standards for weathering of materials, we have been conducting a solar weathering program on a group of six different types of photovoltaic (PV) modules. The methods used include real-time outdoor, accelerated outdoor, and accelerated indoor weathering. We have employed the technique specified in these standards that quantifies exposure totals by the time integral of the ultraviolet (UV) irradiance. In this paper, we report the observed degradation in the test modules as a function of total UV exposure, and give a number of recommendations for future weathering tests that resulted from our first attempt at a formal test program.

  16. On the relationship factor between the PV module temperature and the solar radiation on it for various BIPV configurations

    NASA Astrophysics Data System (ADS)

    Kaplanis, S.; Kaplani, E.

    2014-10-01

    Temperatures of c-Si, pc-Si and a-Si PV modules making part of a roof in a building or hanging outside windows with various inclinations were measured with respect to the Intensity of the solar radiation on them under various environmental conditions. A relationship coefficient f was provided whose values are compared to those from a PV array operating in a free standing mode on a terrace. A theoretical model to predict f was elaborated. According to the analysis, the coefficient f takes higher values for PV modules embedded on a roof compared to the free standing PV array. The wind effect is much stronger for the free standing PV than for any BIPV configuration, either the PV is part of the roof, or placed upon the roof, or is placed outside a window like a shadow hanger. The f coefficient depends on various parameters such as angle of inclination, wind speed and direction, as well as solar radiation. For very low wind speeds the effect of the angle of inclination, β, of the PV module with respect to the horizontal on PV temperature is clear. As the wind speed increases, the heat transfer from the PV module shifts from natural flow to forced flow and this effect vanishes. The coefficient f values range from almost 0.01 m2°C/W for free standing PV arrays at strong wind speeds, vW>7m/s, up to around 0.05 m2°C/W for the case of flexible PV modules which make part of the roof in a BIPV system.

  17. On the relationship factor between the PV module temperature and the solar radiation on it for various BIPV configurations

    SciTech Connect

    Kaplanis, S. Kaplani, E.

    2014-10-06

    Temperatures of c-Si, pc-Si and a-Si PV modules making part of a roof in a building or hanging outside windows with various inclinations were measured with respect to the Intensity of the solar radiation on them under various environmental conditions. A relationship coefficient f was provided whose values are compared to those from a PV array operating in a free standing mode on a terrace. A theoretical model to predict f was elaborated. According to the analysis, the coefficient f takes higher values for PV modules embedded on a roof compared to the free standing PV array. The wind effect is much stronger for the free standing PV than for any BIPV configuration, either the PV is part of the roof, or placed upon the roof, or is placed outside a window like a shadow hanger. The f coefficient depends on various parameters such as angle of inclination, wind speed and direction, as well as solar radiation. For very low wind speeds the effect of the angle of inclination, β, of the PV module with respect to the horizontal on PV temperature is clear. As the wind speed increases, the heat transfer from the PV module shifts from natural flow to forced flow and this effect vanishes. The coefficient f values range from almost 0.01 m{sup 2°}C/W for free standing PV arrays at strong wind speeds, v{sub W}>7m/s, up to around 0.05 m{sup 2°}C/W for the case of flexible PV modules which make part of the roof in a BIPV system.

  18. Proposed acceptance, qualification, and characterization tests for thin-film PV modules

    NASA Technical Reports Server (NTRS)

    Waddington, D.; Mrig, L.; Deblasio, R.; Ross, R.

    1988-01-01

    Details of a proposed test program for PV thin-film modules which the Department of Energy has directed the Solar Energy Research Institute (SERI) to prepare are presented. Results of one of the characterization tests that SERI has performed are also presented. The objective is to establish a common approach to testing modules that will be acceptable to both users and manufacturers. The tests include acceptance, qualification, and characterization tests. Acceptance tests verify that randomly selected modules have similar characteristics. Qualification tests are based on accelerated test methods designed to simulate adverse conditions. Characterization tests provide data on performance in a predefined environment.

  19. System and Battery Charge Control for PV-Powered AC Lighting Systems

    SciTech Connect

    Kern, G.

    1999-04-01

    This report reviews a number of issues specific to stand-alone AC lighting systems. A review of AC lighting technology is presented, which discusses the advantages and disadvantages of various lamps. The best lamps for small lighting systems are compact fluorescent. The best lamps for intermediate-size systems are high- or low-pressure sodium. Specifications for battery charging and load control are provided with the goal of achieving lamp lifetimes on the order of 16,000 to 24,000 hours and battery lifetimes of 4 to 5 years. A rough estimate of the potential domestic and global markets for stand-alone AC lighting systems is presented. DC current injection tests were performed on high-pressure sodium lamps and the test results are presented. Finally, a prototype system was designed and a prototype system controller (with battery charger and DC/AC inverter) was developed and built.

  20. Bottom-Up Cost Analysis of a High Concentration PV Module; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Horowitz, K.; Woodhouse, M.; Lee, H.; Smestad, G.

    2015-04-13

    We present a bottom-up model of III-V multi-junction cells, as well as a high concentration PV (HCPV) module. We calculate $0.65/Wp(DC) manufacturing costs for our model HCPV module design with today’s capabilities, and find that reducing cell costs and increasing module efficiency offer the promising pathways for future cost reductions. Cell costs could be significantly reduced via an increase in manufacturing scale, substrate reuse, and improved manufacturing yields. We also identify several other significant drivers of HCPV module costs, including the Fresnel lens primary optic, module housing, thermal management, and the receiver board. These costs could potentially be lowered by employing innovative module designs.

  1. Reference module selection criteria for accurate testing of photovoltaic (PV) panels

    SciTech Connect

    Roy, J.N.; Gariki, Govardhan Rao; Nagalakhsmi, V.

    2010-01-15

    It is shown that for accurate testing of PV panels the correct selection of reference modules is important. A detailed description of the test methodology is given. Three different types of reference modules, having different I{sub SC} (short circuit current) and power (in Wp) have been used for this study. These reference modules have been calibrated from NREL. It has been found that for accurate testing, both I{sub SC} and power of the reference module must be either similar or exceed to that of modules under test. In case corresponding values of the test modules are less than a particular limit, the measurements may not be accurate. The experimental results obtained have been modeled by using simple equivalent circuit model and associated I-V equations. (author)

  2. SunSine300 AC module. Annual report, July 25, 1995--December 31, 1996

    SciTech Connect

    Russell, M.C.; Handleman, C.K.P.

    1997-08-01

    Under Photovoltaic Manufacturing Technology (PVMaT) 4A1, Ascension Technology (AT) is developing the SunSine300 AC PV module. AT`s goals in this project are to meet Underwriters Laboratory (UL) 1741 requirements, obtain Federal Communications Commission (FCC) Class B verification, complete the AC module system design and development, advance the inverter design, design for manufacture, design for reliability, design for serviceability, and demonstrate commercialization through production and sale of about 100 units. To meet these goals, AT corrected a number of deficiencies identified by UL`s preliminary investigation before proceeding to the full UL investigation; a SunSine300 prototype was tested and found to comply with FCC Class B requirements; AT designed a complete line of balance-of-systems hardware for the SunSine 300; AT`s design and performance advancements include accomplishing a total harmonic distortion drop from 5% to 2%, devising a method to eliminate false detection of zero crossings that could damage the inverter, improving the anti-islanding with the addition of AT`s proprietary ZEBRA technique, and redesigning the enclosure for thermal performance, manufacturability, and UL and FCC approval; performing extensive testing in Phase 2 to discover failure modes and susceptibility to aging; and designing the SunSine300 to be easily and safely serviced. 3 figs., 3 tabs.

  3. Challenge to Move from 'One Size Fits All' to PV Modules the Customer Needs: Preprint

    SciTech Connect

    Kurtz, S.; Wohlgemuth, J.; Hacke, P.; Bosco, N.; Kempe, M.; Smith, R.; Packard, C. E.

    2011-09-01

    Historically, PV companies requested a single qualification test for a single product. As the market has grown, there have been increasing opportunities for companies to differentiate their products while still maintaining high manufacturing volumes of each product. At the same time, as PV is deployed in an increasingly broad range of conditions, modules need to be able to withstand a wide range of stresses. In some cases, targeting a specific deployment condition may allow reduction of product cost. Realizing this opportunity will require the ability to confidently predict long-term performance based on accelerated tests and known weather conditions. By working together, the community can most quickly develop tests that identify which products perform well under which conditions. This paper discusses some of the challenges of predicting long-term PV performance, including the wide range of stresses that may be encountered, the variability of the stresses from moment to moment, the complexity of some degradation mechanisms, and the dependence of accelerated testing on module geometry. The paper also describes two international projects that deal with location-specific durability evaluation and long-term module performance.

  4. UV-accelerated test based on analysis of field-exposed PV modules

    NASA Astrophysics Data System (ADS)

    Shioda, T.

    2011-09-01

    We proposed an UV accelerated test condition for an EVA encapsulant, based on analysis of long term field exposed PV modules. We found that strong UV irradiation into EVA encapsulant test sample led to the fast decomposition of UV absorber formulated in EVA encapsulant, which has never seen in the field exposed PV modules. Thus, the integrating UV intensity of 60 W/m2 and black panel temperature of 110°C using a xenon weather-o-meter were suitable as an UV accelerated test condition. With this proposed test condition, which shows that 1 week exposure by xenon light corresponds to 1 year field exposure, we can predict discoloration rate of EVA encapsulant. In addition, we evaluated change in peel strength to glass for Mitsui's and the other commercially available EVA encapsulants during UV accelerated test with the proposed condition. There was no large change in peel strength for our EVA encapsulant during the UV accelerated test. On the other hand, we observed that the competitor's EVA encapsulant showed the large decrease of peel strength to glass at early stage, even no change in yellowness index (YI). This result indicates not only YI change but also peel strength change should be evaluated for design of reliable PV module and encapsulant.

  5. Degradation evaluation of PV modules operating under Northern Saharan environment in Algeria

    NASA Astrophysics Data System (ADS)

    Charrouf, Omar; Betka, Achour; hadef, Hefaidh; Djebabra, Mebarek; Tiar, Mourad

    2017-02-01

    The degradation of Monocrystalline-silicone solar PV modules in Biskra, semi-arid climate, at the north of the Algerian Sahara was studied. As first inspection in this region, the electrical parameters of two PV modules A and B fielded during two different periods, ten and five years respectively, are measured under real climatic conditions and their I-V characteristics were fitted. The standardized I-V characteristics was performed using translation method and compared to their initial I-V characteristics at standard test conditions(STC) given by the manufacturer. The main important parameters of the studied PV modules: short-circuit current Ish, open circuit voltage Voc and maximum power Pmax are evaluated and then compared to the STC parameters to estimate their degradation and degradation rates according to their exposure duration. Moreover, other possible defects are explored by visual inspection method. The results show degradation rates of maximum power nearing 1.7 %/year and 3.6%/year for the ten and five operating years.

  6. A more elemental examination of factors governing PV module environmental stability

    SciTech Connect

    Jester, T.L.; Aldrich, D.; Hummel, J.; Wieting, R.D.; Galica, J.P.; Thoma, L.

    1994-12-31

    To date, photovoltaic module reliability studies have primarily focused on retention of initial power when exposed to various environmental stresses. While power of a PV module is one reliability measure, the fundamental parameters affecting photovoltaic module stability are typically not measured for baseline analysis. This study examines these questions in context of fundamental parameters, in an attempt to gain insight at a more elemental level than possible using power measurements. One of the fundamental parameters in PV module reliability is the adhesion of the encapsulant EVA to various module surfaces. The analysis of surface adhesion, both in its initial state, and as it changes with various exposures is studied here, primarily focusing on adhesion of EVA to glass, cell surfaces and the interconnect ribbon. Of particular interest is the affect of manufacturing processes and surface cleanliness on this bond strength. Measurements of EVA adhesion and how it is affected by surface contamination due to residual solder flux have also been specifically quantified. The summary analysis looked at EVA bonds as a function of environmental exposures. The results of this analysis shows that initial strength of EVA bonds are quite high, these are diminished by both surface contamination effects and environmental exposures. The ultimate bond strength and the ratio to the initial value are variable dependent upon the exposure.

  7. Results of I-V Curves and Visual Inspection of PV Modules Deployed at TEP Solar Test Yard (Poster)

    SciTech Connect

    McNutt, P.; Wohlgemuth, J.; Miller, D.; Stoltenberg, B.

    2014-02-01

    The purpose of the PV Service Life Prediction project is to examine and report on how solar modules are holding up after being in the field for 5 or more years. This poster presents the common problems crystalline-silicon and thin-film modules exhibit, including details of modules from three manufactures that were tested January 13-16, 2014.

  8. Effect of shading on the switching of bypass diodes in PV modules

    NASA Astrophysics Data System (ADS)

    Shiradkar, Narendra; Schneller, Eric; Dhere, Neelkanth; Gade, Vivek

    2014-10-01

    Bypass diodes are installed in Photovoltaic (PV) modules in order to prevent the application of high reverse voltage across the shaded cells in the event of partial shading of the module. Crystalline silicon (c-Si) modules have one bypass diode per 18-20 cells while thin film modules have at most one bypass diode per module. Ideally, bypass diodes are expected to turn on as soon as a current mismatch is detected between various strings of cells inside the module, which typically occurs in the event of partial shading. However, limited information is available on the actual switching characteristics of bypass diodes in field. In this paper, effect of incremental shading of various cells on the flasher I-V curve of a commercial 60-cell c-Si module was studied. Cell combinations in various strings were shaded with operational bypass diodes in the module and effect on module performance parameters such as Voc, Isc, Pmax and Fill Factor was discussed. Consequently one bypass diode in the module was short circuited and open circuited respectively and again the effect of shading on the I-V curve was investigated. Techniques for identifying short circuited and open circuited bypass diodes from I-V curve are presented.

  9. Energy performance of semi-transparent PV modules for applications in buildings

    NASA Astrophysics Data System (ADS)

    Fung, Yu Yan

    Owing to the increasing awareness on energy conservation and environmental protection, building-integrated photovoltaic (BIPV) has been developed rapidly in the past decade. A number of research studies have been conducted on the energy performance of BIPV systems. However, most of the previous studies focused on the systems that incorporated with opaque type PV modules, little attention has been devoted to semi-transparent type PV modules, which have been commonly integrated in modern architectures. This thesis aims at evaluating the energy performance of the semi-transparent BIPV modules, including heat gains to the indoor environment, power generation from the PV modules and daylight utilization. Solar radiation intensity on PV module's surfaces is an essential parameter for assessing energy performance of the PV modules. Different slope solar radiation models are analyzed and compared. The model that best suits Hong Kong situations is selected for the further development of the energy performance of the BIPV modules. The optimum orientation and tilted angle are determined in the analysis. In addition to the solar radiation models, a detailed investigation on the heat gain through the semi-transparent BIPV modules is carried out in this study. A one-dimensional transient heat transfer model, the SPVHG model, for evaluating the thermal performance of the semi-transparent BIPV modules is developed. The SPVHG model considers in detail the energy that is transmitted, absorbed and reflected in each element of the BIPV modules such as solar cells and glass layers. A computer program of the model is written accordingly. By applying the SPVHG model, the heat gain through the semi-transparent BIPV module of any thickness can be determined for any solar irradiance level. The annual performance can also be assessed by inputting annual weather data to the model. In order to verify the SPVHG model, laboratory tests have been carried out on semi-transparent BIPV modules. A

  10. Nonlinear phenomenon in monocrystalline silicon based PV module for low power system: Lead acid battery for low energy storage

    NASA Astrophysics Data System (ADS)

    El Amrani, A.; El Amraoui, M.; El Abbassi, A.; Messaoudi, C.

    2014-11-01

    In the present work, we report the indoor photo-electrical measurements of monocrystalline silicon based photovoltaic (PV) module associated with 4 Ah lead acid battery as a storage unit for low power PV system applications. Concerning the PV module, our measurements show, at low illumination regime, that the short circuit current ISC increases linearly with the illumination power levels. Moreover, for high illumination levels, the mechanism of bimolecular recombination and space charge limitation may be intensified and hence the short current of the PV module ISCMod depends sublinearly on the incident optical power; the behavior is nonlinear. For the open circuit voltage of the PV module VOCMod measurements, a linear variation of the VOCMod versus the short circuit current in semi-logarithmic scale has been noticed. The diode ideality factor n and diode saturation current Is have been investigated; the values of n and Is are approximately of 1.3 and 10-9 A, respectively. In addition, we have shown, for different discharging-charging currents rates (i.e. 0.35 A, 0.2 A and 0.04 A), that the battery voltage decreases with discharging time as well as discharging battery capacity, and on the other hand it increases with the charging time and will rise up until it maximized value. The initial result shows the possibility to use such lead acid battery for low power PV system, which is generally designed for the motorcycle battery.

  11. The Influence of PV Module Materials and Design on Solder Joint Thermal Fatigue Durability

    SciTech Connect

    Bosco, Nick; Silverman, Timothy J.; Kurtz, Sarah

    2016-11-01

    Finite element model (FEM) simulations have been performed to elucidate the effect of flat plate photovoltaic (PV) module materials and design on PbSn eutectic solder joint thermal fatigue durability. The statistical method of Latin Hypercube sampling was employed to investigate the sensitivity of simulated damage to each input variable. Variables of laminate material properties and their thicknesses were investigated. Using analysis of variance, we determined that the rate of solder fatigue was most sensitive to solder layer thickness, with copper ribbon and silicon thickness being the next two most sensitive variables. By simulating both accelerated thermal cycles (ATCs) and PV cell temperature histories through two characteristic days of service, we determined that the acceleration factor between the ATC and outdoor service was independent of the variables sampled in this study. This result implies that an ATC test will represent a similar time of outdoor exposure for a wide range of module designs. This is an encouraging result for the standard ATC that must be universally applied across all modules.

  12. Impact of heavy soiling on the power output of PV modules

    NASA Astrophysics Data System (ADS)

    Schill, Christian; Brachmann, Stefan; Heck, Markus; Weiss, Karl-Anders; Koehl, Michael

    2011-09-01

    Fraunhofer ISE is running a PV-module outdoor testing set-up on the Gran Canaria island, one of the Canary Island located west of Morroco in the Atlantic Ocean. The performance of the modules is assessed by IV-curve monitoring every 10 minutes. The electronic set-up of the monitoring system - consisting of individual electronic loads for each module which go into an MPP-tracking mode between the IV-measurements - will be described in detail. Soiling of the exposed modules happened because of building constructions nearby. We decided not to clean the modules, but the radiation sensors and recorded the decrease of the power output and the efficiency over time. The efficiency dropped to 20 % within 5 months before a heavy rain and subsequently the service personnel on site cleaned the modules. A smaller rain-fall in between washed the dust partly away and accumulated it at the lower part of the module, what could be concluded from the shape of the IV-curves, which were similar to partial shading by hot-spot-tests and by partial snow cover.

  13. System Voltage Potential-Induced Degradation Mechanisms in PV Modules and Methods for Test: Preprint

    SciTech Connect

    Hacke, P.; Terwilliger, K.; Smith, R.; Glick, S.; Pankow, J.; Kempe, M.; Kurtz, S.; Bennett, I.; Kloos, M.

    2011-07-01

    Over the past decade, degradation and power loss have been observed in PV modules resulting from the stress exerted by system voltage bias. This is due in part to qualification tests and standards that do not adequately evaluate for the durability of modules to the long-term effects of high voltage bias experienced in fielded arrays. High voltage can lead to module degradation by multiple mechanisms. The extent of the voltage bias degradation is linked to the leakage current or coulombs passed from the silicon active layer through the encapsulant and glass to the grounded module frame, which can be experimentally determined; however, competing processes make the effect non-linear and history-dependent. Appropriate testing methods and stress levels are described that demonstrate module durability to system voltage potential-induced degradation (PID) mechanisms. This information, along with outdoor testing that is in progress, is used to estimate the acceleration factors needed to evaluate the durability of modules to system voltage stress. Na-rich precipitates are observed on the cell surface after stressing the module to induce PID in damp heat with negative bias applied to the active layer.

  14. System Voltage Potential-Induced Degradation Mechanisms in PV Modules and Methods for Test

    SciTech Connect

    Hacke, P.; Terwilliger, K.; Smith, R.; Glick, S.; Pankow, J.; Kempe, M.; Kurtz, S.; Bennett, I.; Kloos, M.

    2011-01-01

    Over the past decade, degradation and power loss have been observed in PV modules resulting from the stress exerted by system voltage bias. This is due in part to qualification tests and standards that do not adequately evaluate for the durability of modules to the long-term effects of high voltage bias experienced in fielded arrays. High voltage can lead to module degradation by multiple mechanisms. The extent of the voltage bias degradation is linked to the leakage current or culombs passed from the silicon active layer through the encapsulant and glass to the grounded module frame, which can be experimentally determined; however, competing processes make the effect non-linear and history-dependent. Appropriate testing methods and stress levels are described that demonstrate module durability to system voltage potential-induced degradation (PID) mechanisms. This information, along with outdoor testing that is in progress, is used to estimate the acceleration factors needed to evaluate the durability of modules to system voltage stress. Na-rich precipitates are observed on the cell surface after stressing the module to induce PID in damp heat with negative bias applied to the active layer.

  15. Influence of volcanic tephra on photovoltaic (PV)-modules: An experimental study with application to the 2010 Eyjafjallajokull eruption, Iceland

    NASA Astrophysics Data System (ADS)

    Zorn, Edgar; Walter, Thomas R.

    2016-04-01

    Large volcanic eruptions may lead to significant tephra dispersion, crossing borders and affecting distant and industrial societies in various ways. While the effects of volcanic ash clouds on the aviation industry have been recognized, damaging effects on the photovoltaic energy sector are poorly investigated. Here we describe the influence of volcanic tephra deposition on photovoltaic (PV) modules that we experimentally analyzed and evaluated. A systematic set of experiments was conducted under controlled conditions using an artificial light source and measuring the electrical power generated from the PV-modules with the aim to determine the dependency of the amount of tephra covering a module and its subsequent loss in power production (measured in voltage and current) as well as the influence of the tephra grain size. We find that a mass of fine tephra has a stronger influence on the PV-modules power generation than the same mass of coarser particles. An application to the fine-grained 2010 Eyjafjallajökull eruption in Iceland and the resulting ash-cloud reveals that the power produced by PV-modules in continental Europe might have been affected significantly. Deposits were thick enough to cause complete failures of PV-modules up to a distance of about 300 km downwind. Although this distance is largely over the ocean in this particular case, our results imply that similar and larger eruptions of other volcanoes elsewhere might harm commercial or private energy production at distances of hundreds to thousands of kilometers from the volcano. Given that volcanic eruptions are frequent and the fact that the PV-industry is growing rapidly, negative impacts are expected in the future, requiring close tephra dispersion monitoring and PV-maintenance strategies.

  16. Transcription Factors PvERF15 and PvMTF-1 Form a Cadmium Stress Transcriptional Pathway1[OPEN

    PubMed Central

    Lin, Tingting; Yang, Wanning; Lu, Wen; Wang, Ying

    2017-01-01

    In plants, cadmium (Cd)-responsive transcription factors are key downstream effectors of Cd stress transcriptional pathways, which are capable of converging Cd stress signals through triggering the expression of Cd detoxification genes. However, the upstream transcriptional regulatory pathways that modulate their responses to Cd are less clear. Previously, we identified the bean (Phaseolus vulgaris) METAL RESPONSE ELEMENT-BINDING TRANSCRIPTION FACTOR1 (PvMTF-1) that responds to Cd and confers Cd tolerance in planta. Here, we demonstrate an upstream transcriptional regulation of the PvMTF-1 response to Cd. Using a yeast one-hybrid system, we cloned the bean ETHYLENE RESPONSE FACTOR15 (PvERF15) that binds to the PvMTF-1 promoter. PvERF15 was strongly induced by Cd stress, and its overexpression resulted in the up-regulation of PvMTF-1. DNA-protein interaction assays further revealed that PvERF15 binds directly to a 19-bp AC-rich element in the PvMTF-1 promoter. The AC-rich element serves as a positive element bound by PvERF15 to activate gene expression. More importantly, knockdown of PvERF15 by RNA interference resulted in reduced Cd-induced expression of PvMTF-1. PvERF15 seems to be involved in Cd tolerance, since knockdown of PvERF15 by RNA interference in bean leaf discs decreased Cd tolerance in a transient assay. Since PvERF15 is a component of the Cd stress transcriptional pathway in beans and PvMTF-1 is one of its downstream targets, our findings provide a PvERF15/PvMTF-1 transcriptional pathway and thereby contribute to the understanding of Cd stress transcriptional regulatory pathways in plants. PMID:28073984

  17. Performance Stabilization of CdTe PV Modules using Bias and Light

    SciTech Connect

    Silverman, T. J.; Deceglie, M. G.; Marion, B.; Kurtz, S. R.

    2014-07-01

    Reversible performance changes due to light exposure frustrate repeatable performance measurements on CdTe PV modules. It is common to use extended light-exposure to ensure that measurements are representative of outdoor performance. We quantify the extent to which such a light-exposed state depends on module temperature and consider bias in the dark to aid in stabilization. We evaluate the use of dark forward bias to bring about a performance state equivalent to that obtained with light exposure, and to maintain a light-exposed state prior to STC performance measurement. Our results indicate that the most promising method for measuring a light-exposed state is to use light exposure at controlled temperature followed by prompt STC measurement with a repeatable time interval between exposure and the STC measurement.

  18. Final Technical Report - Recovery Act: Organic Coatings as Encapsulants for Low Cost, High Performance PV Modules

    SciTech Connect

    Stuart Hellring; Jiping Shao; James Poole

    2011-12-05

    The objective of this project was to evaluate the feasibility of utilizing PPG's commercial organic coatings systems as efficient, modernized encapsulants for low cost, high performance, thin film photovoltaic modules. Our hypothesis was that the combination of an anticorrosive coating with a more traditional barrier topcoat would mitigate many electrochemical processes that are now responsible for the significant portion of photovoltaic (PV) failures, thereby nullifying the extremely high moisture barrier requirements of currently used encapsulation technology. Nine commercially available metal primer coatings and six commercially available top coatings were selected for screening. Twenty-one different primer/top coat combinations were evaluated. The primer coatings were shown to be the major contributor to corrosion inhibition, adhesion, and barrier properties. Two primer coatings and one top coating were downselected for testing on specially-fabricated test modules. The coated test modules passed initial current leakage and insulation testing. Damp Heat testing of control modules showed visible corrosion to the bus bar metal, whereas the coated modules showed none. One of the primer/top coat combinations retained solar power performance after Damp Heat testing despite showing some delamination at the EVA/solar cell interface. Thermal Cycling and Humidity Freeze testing resulted in only one test module retaining its power performance. Failure modes depended on the particular primer/top coating combination used. Overall, this study demonstrated that a relatively thin primer/top coating has the potential to replace the potting film and backsheet in crystalline silicon-based photovoltaic modules. Positive signals were received from commercially available coatings developed for applications having performance requirements different from those required for photovoltaic modules. It is likely that future work to redesign and customize these coatings would result in a

  19. Silicon PV module customization using laser technology for new BIPV applications

    NASA Astrophysics Data System (ADS)

    García-Ballesteros, Juan José; Lauzurica, Sara; Morales, Miguel; del Caño, Teodosio; Valencia, Daniel; Casado, Leonardo; Balenzategui, José Lorenzo; Molpeceres, Carlos

    2014-10-01

    It is well known that lasers have helped to increase efficiency and to reduce production costs in the photovoltaic (PV) sector in the last two decades, appearing in most cases as the ideal tool to solve some of the critical bottlenecks of production both in thin film (TF) and crystalline silicon (c-Si) technologies. The accumulated experience in these fields has brought as a consequence the possibility of using laser technology to produce new Building Integrated Photovoltaics (BIPV) products with a high degree of customization. However, to produce efficiently these personalized products it is necessary the development of optimized laser processes able to transform standard products in customized items oriented to the BIPV market. In particular, the production of semitransparencies and/or freeform geometries in TF a-Si modules and standard c-Si modules is an application of great interest in this market. In this work we present results of customization of both TF a-Si modules and standard monocrystalline (m-Si) and policrystalline silicon (pc-Si) modules using laser ablation and laser cutting processes. A discussion about the laser processes parameterization to guarantee the functionality of the device is included. Finally some examples of final devices are presented with a full discussion of the process approach used in their fabrication.

  20. In-situ comparison of thermal measurement technologies for interpretation of PV module temperature de-rating effects

    NASA Astrophysics Data System (ADS)

    Elwood, Teri; Bennett, Whit; Lai, Teh; Simmons-Potter, Kelly

    2016-09-01

    It is well known that the efficiency of a photovoltaic (PV) module is strongly impacted by its temperature such that higher temperatures lead to lower energy conversion efficiencies. An accurate measurement of the temperature de-rating effect, therefore, is vital to the correct interpretation of PV module performance under varied environmental conditions. The current work investigates and compares methods for performing measurements of module temperature both in the lab and in field-test environments. A comparison of several temperature measurement devices was made in order to establish the ideal sensor configuration for quantifying module operating temperature. Sensors were also placed in various locations along a string of up to eight photovoltaic modules to examine the variance in operating temperature with position in the string and within a larger array of strings.

  1. Development of New Low-Cost, High-Performance, PV Module Encapsulant/Packaging Materials: Final Technical Progress Report, 22 October 2002 - 15 November 2007

    SciTech Connect

    Tucker, R.

    2008-04-01

    Report on objectives to work with U.S.-based PV module manufacturers (c-Si, a-Si, CIS, other thin films) to develop/qualify new low-cost, high-performance PV module encapsulant/packaging materials, and processes using the packaging materials.

  2. Development and application of a UV light source for PV-module testing

    NASA Astrophysics Data System (ADS)

    Koehl, Michael; Philipp, Daniel; Lenck, Norbert; Zundel, Matthias

    2009-08-01

    Photovoltaic (PV)-modules are exposed to solar irradiation, which includes Ultra-violet (UV) light. UV light is wellknown as degradation factor for polymeric materials, as used for encapsulation of PV-cells. Therefore they are protected by UV-filtering glass or UV protecting additives. The UV-stability is only tested on a very low level (total UV energy of 15kWh/m2) according to the actual type approval standards (IEC 61215, IEC61646, e.g.). An undefined acceleration is provided by the testing temperature of 60°C. The real UV-dose can reach more than 120 kWh/m2 per year, however. The module-temperature during high UV-irradiation ranges between 40°C and 60°C, usually. The main reason for the inadequate test conditions is the lack of well-defined and inexpensive UV-light sources and therefore small test capacities. We developed an UV-radiation unit based on fluorescence tubes, which have the advantage of low visible and NIR irradiation avoiding overheating of the samples. The spectral irradiation is solar-like in the short-wavelength UV and lower in the long-wavelength UV, with a limited number of disturbing emission-lines. The design of the unit has been optimized for high UV-intensities up to 5X and usage on both sides. Our prototype has an area of 1.7m * 3m, which yields an usable testing area of 6m *1.7m. The unit is designed for usage in humid ambient in a temperature range up to 90°C for the future development of combined damp-heat and UV tests, in order to get the tests closer to reality.

  3. Identification of PV solar cells and modules parameters using the genetic algorithms: Application to maximum power extraction

    SciTech Connect

    Zagrouba, M.; Sellami, A.; Bouaicha, M.; Ksouri, M.

    2010-05-15

    In this paper, we propose to perform a numerical technique based on genetic algorithms (GAs) to identify the electrical parameters (I{sub s}, I{sub ph}, R{sub s}, R{sub sh}, and n) of photovoltaic (PV) solar cells and modules. These parameters were used to determine the corresponding maximum power point (MPP) from the illuminated current-voltage (I-V) characteristic. The one diode type approach is used to model the AM1.5 I-V characteristic of the solar cell. To extract electrical parameters, the approach is formulated as a non convex optimization problem. The GAs approach was used as a numerical technique in order to overcome problems involved in the local minima in the case of non convex optimization criteria. Compared to other methods, we find that the GAs is a very efficient technique to estimate the electrical parameters of PV solar cells and modules. Indeed, the race of the algorithm stopped after five generations in the case of PV solar cells and seven generations in the case of PV modules. The identified parameters are then used to extract the maximum power working points for both cell and module. (author)

  4. Nonlinear modal interaction in HVDC/AC power systems with dc power modulation

    SciTech Connect

    Ni, Y.X.; Vittal, V.; Kliemann, W.; Fouad, A.A.

    1996-11-01

    In this paper investigation of nonlinear modal interaction using the normal form of vector fields technique is extended to HVDC/AC power systems with dc power modulation. The ac-dc interface equations are solved to form a state space model with second order approximation. Using the normal form technique, the system`s nonlinear dynamic characteristics are obtained. The proposed approach is applied to a 4-generator HVDC/AC test power system, and compare with the time domain solution.

  5. RNA-seq Analysis Reveals That an ECF σ Factor, AcsS, Regulates Achromobactin Biosynthesis in Pseudomonas syringae pv. syringae B728a

    PubMed Central

    Greenwald, Jessica W.; Greenwald, Charles J.; Philmus, Benjamin J.; Begley, Tadhg P.; Gross, Dennis C.

    2012-01-01

    Iron is an essential micronutrient for Pseudomonas syringae pv. syringae strain B728a and many other microorganisms; therefore, B728a has evolved methods of iron acquirement including the use of iron-chelating siderophores. In this study an extracytoplasmic function (ECF) sigma factor, AcsS, encoded within the achromobactin gene cluster is shown to be a major regulator of genes involved in the biosynthesis and secretion of this siderophore. However, production of achromobactin was not completely abrogated in the deletion mutant, implying that other regulators may be involved such as PvdS, the sigma factor that regulates pyoverdine biosynthesis. RNA-seq analysis identified 287 genes that are differentially expressed between the AcsS deletion mutant and the wild type strain. These genes are involved in iron response, secretion, extracellular polysaccharide production, and cell motility. Thus, the transcriptome analysis supports a role for AcsS in the regulation of achromobactin production and the potential activity of both AcsS and achromobactin in the plant-associated lifestyle of strain B728a. PMID:22529937

  6. Storage Free Smart Energy Management for Frequency Control in a Diesel-PV-Fuel Cell-Based Hybrid AC Microgrid.

    PubMed

    Sekhar, P C; Mishra, S

    2016-08-01

    This paper proposes a novel, smart energy management scheme for a microgrid, consisting of a diesel generator and power electronic converter interfaced renewable energy-based generators, such as photovoltaic (PV) and fuel cell, for frequency regulation without any storage. In the proposed strategy, output of the PV is controlled in coordination with other generators using neurofuzzy controller, either only for transient frequency regulation or for both transient and steady-state frequency regulation, depending on the load demand, thereby eliminating the huge storage requirements. The option of demand response control is also explored along with the generation control. For accurate and quick tracking of maximum power point and its associated reserve power from the PV generator, this paper also proposes a novel adaptive-predictor-corrector-based tracking mechanism.

  7. Development of a low-cost integrated 20-kW ac solar tracking sub- array for grid-connected PV power system applications. Phase 1, Annual technical report, 11 July 1995--31 July 1996

    SciTech Connect

    Stern, M.; West, R.; Fourer, G.; Whalen, W.; Van Loo, M.; Duran, G.

    1997-06-01

    The overall goal of this effort is to reduce the installed cost of utility scale grid connected photovoltaic power systems. The focus of the effort is on ``BOS`` (Balance-Of-System) component manufacturing technology, which essentially involves all PV power system engineering, manufacturing, assembly and construction tasks from the receipt of a PV module to the deliver of grid connected electricity.

  8. Activities of the task group 8 on thin film PV module reliability (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.

    2016-09-01

    Photovoltaic (PV) modules and systems are being used increasingly to provide renewable energy to schools, residences, small businesses and utilities. At this time, the home owners and small businesses have considerable difficulty in detecting module and/or system degradation and especially enforcing warranty. It needs to be noted that IEC 61215-1 (test req.), -2 (test proc.) and -1-1 (c-Si) are forecasted to be circulated end of Feb 2016 and only editorial changes would be possible. 61215 series does include thin film technologies and would be replacing 61646. Moreover, IEC 61215-1, section 7.2 power output and electric circuitry does contain significant changes to acceptance criteria regarding rated label values, particularly rated power. Even though it is believed that consensus could be achieved within IEC TC82 WG2, some of the smaller players that do not participate actively in IEC TC82 - may not be surprised and must be informed. The other tech specific parts 61215-1-2 (CdTe), -1-3 (a-Si, µc-Si) and -1-4 (CIS, CIGS) are out for comments. The IEC closing date was January 29, 2016. The additions alternative damp heat (DH) test proposed Solar Frontier is being reviewed. In the past, only 600 V systems were permitted in the grid-connected residential and commercial systems in the US. The US commercial systems can now use higher voltage (1,000-1500V) in order to reduce BOS component costs. It is believed that there would not be any problems. The Task Group 8 is collecting data on higher voltage systems.

  9. The Class II Trehalose 6-phosphate Synthase Gene PvTPS9 Modulates Trehalose Metabolism in Phaseolus vulgaris Nodules

    PubMed Central

    Barraza, Aarón; Contreras-Cubas, Cecilia; Estrada-Navarrete, Georgina; Reyes, José L.; Juárez-Verdayes, Marco A.; Avonce, Nelson; Quinto, Carmen; Díaz-Camino, Claudia; Sanchez, Federico

    2016-01-01

    Legumes form symbioses with rhizobia, producing nitrogen-fixing nodules on the roots of the plant host. The network of plant signaling pathways affecting carbon metabolism may determine the final number of nodules. The trehalose biosynthetic pathway regulates carbon metabolism and plays a fundamental role in plant growth and development, as well as in plant-microbe interactions. The expression of genes for trehalose synthesis during nodule development suggests that this metabolite may play a role in legume-rhizobia symbiosis. In this work, PvTPS9, which encodes a Class II trehalose-6-phosphate synthase (TPS) of common bean (Phaseolus vulgaris), was silenced by RNA interference in transgenic nodules. The silencing of PvTPS9 in root nodules resulted in a reduction of 85% (± 1%) of its transcript, which correlated with a 30% decrease in trehalose contents of transgenic nodules and in untransformed leaves. Composite transgenic plants with PvTPS9 silenced in the roots showed no changes in nodule number and nitrogen fixation, but a severe reduction in plant biomass and altered transcript profiles of all Class II TPS genes. Our data suggest that PvTPS9 plays a key role in modulating trehalose metabolism in the symbiotic nodule and, therefore, in the whole plant. PMID:27847509

  10. The Class II Trehalose 6-phosphate Synthase Gene PvTPS9 Modulates Trehalose Metabolism in Phaseolus vulgaris Nodules.

    PubMed

    Barraza, Aarón; Contreras-Cubas, Cecilia; Estrada-Navarrete, Georgina; Reyes, José L; Juárez-Verdayes, Marco A; Avonce, Nelson; Quinto, Carmen; Díaz-Camino, Claudia; Sanchez, Federico

    2016-01-01

    Legumes form symbioses with rhizobia, producing nitrogen-fixing nodules on the roots of the plant host. The network of plant signaling pathways affecting carbon metabolism may determine the final number of nodules. The trehalose biosynthetic pathway regulates carbon metabolism and plays a fundamental role in plant growth and development, as well as in plant-microbe interactions. The expression of genes for trehalose synthesis during nodule development suggests that this metabolite may play a role in legume-rhizobia symbiosis. In this work, PvTPS9, which encodes a Class II trehalose-6-phosphate synthase (TPS) of common bean (Phaseolus vulgaris), was silenced by RNA interference in transgenic nodules. The silencing of PvTPS9 in root nodules resulted in a reduction of 85% (± 1%) of its transcript, which correlated with a 30% decrease in trehalose contents of transgenic nodules and in untransformed leaves. Composite transgenic plants with PvTPS9 silenced in the roots showed no changes in nodule number and nitrogen fixation, but a severe reduction in plant biomass and altered transcript profiles of all Class II TPS genes. Our data suggest that PvTPS9 plays a key role in modulating trehalose metabolism in the symbiotic nodule and, therefore, in the whole plant.

  11. Space Station Photovoltaic power modules

    NASA Technical Reports Server (NTRS)

    Tatro, Charles A.

    1988-01-01

    Silicon cell Photovoltaic (PV) power modules are key components of the Space Station Electrical Power System (EPS) scheduled to begin deployment in 1994. Four PV power modules, providing 75 KWe of user ac power, form the cornerstone of the EPS; which is comprised of Photovoltaic (PV) power modules, Solar Dynamic (SD) power modules, and the Power Management and Distribution (PMAD) system. The PV modules are located on rotating outboard sections of the Space Station (SS) structure and each module incorporates its own nickel-hydrogen energy storage batteries, its own thermal control system, and some autonomous control features. The PV modules are a cost-effective and technologically mature approach for providing reliable SS electrical power and are a solid base for EPS growth, which is expected to reach 300 KWe by the end of the Space Station's 30-year design lifetime.

  12. Plasmalemmal vesicle associated protein (PV1) modulates SV40 virus infectivity in CV-1 cells.

    PubMed

    Tse, Dan; Armstrong, David A; Oppenheim, Ariella; Kuksin, Dmitry; Norkin, Leonard; Stan, Radu V

    2011-08-26

    Plasmalemmal vesicle associated protein (Plvap/PV1) is a structural protein required for the formation of the stomatal diaphragms of caveolae. Caveolae are plasma membrane invaginations that were implicated in SV40 virus entry in primate cells. Here we show that de novo Plvap/PV1 expression in CV-1 green monkey epithelial cells significantly reduces the ability of SV40 virus to establish productive infection, when cells are incubated with low concentrations of the virus. However, in presence of high viral titers PV1 has no effect on SV40 virus infectivity. Mechanistically, PV1 expression does not reduce the cell surface expression of known SV40 receptors such as GM1 ganglioside and MHC class I proteins. Furthermore, PV1 does not reduce the binding of virus-like particles made by SV40 VP1 protein to the CV-1 cell surface and does not impact their internalization when cells are incubated with either high or low VLP concentrations. These results suggest that PV1 protein is able to block SV40 infectivity at low but not at high viral concentration either by interfering with the infective internalization pathway at the cell surface or at a post internalization step.

  13. Plasmalemmal vesicle associated protein (PV1) modulates SV40 virus infectivity in CV-1 cells

    PubMed Central

    Tse, Dan; Armstrong, David A.; Oppenheim, Ariella; Kuksin, Dimitry; Norkin, Leonard; Stan, Radu V.

    2011-01-01

    Plasmalemmal vesicle associated protein (Plvap/PV1) is a structural protein required for the formation of the stomatal diaphragms of caveolae. Caveolae are plasma membrane invaginations that were implicated in SV40 virus entry in primate cells. Here we show that de novo Plvap/PV1 expression in CV-1 green monkey epithelial cells significantly reduces the ability of SV40 virus to establish productive infection, when cells are incubated with low concentrations of the virus. However, in presence of high viral titers PV1 has no effect on SV40 virus infectivity. Mechanistically, PV1 expression does not reduce the cell surface expression of known SV40 receptors such as GM1 ganglioside and MHC class I proteins. Furthermore, PV1 does not reduce the binding of virus-like particles made by SV40 VP1 protein to the CV-1 cell surface and does not impact their internalization when cells are incubated with either high or low VLP concentrations. These results suggest that PV1 protein is able to block SV40 infectivity at low but not at high viral concentration either by interfering with the infective internalization pathway at the cell surface or at a post internalization step. PMID:21827737

  14. Module Twelve: Series AC Resistive-Reactive Circuits; Basic Electricity and Electronics Individualized Learning System.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    The module covers series circuits which contain both resistive and reactive components and methods of solving these circuits for current, voltage, impedance, and phase angle. The module is divided into six lessons: voltage and impedance in AC (alternating current) series circuits, vector computations, rectangular and polar notation, variational…

  15. Creating dynamic equivalent PV circuit models with impedance spectroscopy for arc-fault modeling.

    SciTech Connect

    Johnson, Jay Dean; Kuszmaul, Scott S.; Strauch, Jason E.; Schoenwald, David Alan

    2011-06-01

    Article 690.11 in the 2011 National Electrical Code{reg_sign} (NEC{reg_sign}) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc fault protection device. Currently there is little experimental or empirical research into the behavior of the arcing frequencies through PV components despite the potential for modules and other PV components to filter or attenuate arcing signatures that could render the arc detector ineffective. To model AC arcing signal propagation along PV strings, the well-studied DC diode models were found to inadequately capture the behavior of high frequency arcing signals. Instead dynamic equivalent circuit models of PV modules were required to describe the impedance for alternating currents in modules. The nonlinearities present in PV cells resulting from irradiance, temperature, frequency, and bias voltage variations make modeling these systems challenging. Linearized dynamic equivalent circuits were created for multiple PV module manufacturers and module technologies. The equivalent resistances and capacitances for the modules were determined using impedance spectroscopy with no bias voltage and no irradiance. The equivalent circuit model was employed to evaluate modules having irradiance conditions that could not be measured directly with the instrumentation. Although there was a wide range of circuit component values, the complex impedance model does not predict filtering of arc fault frequencies in PV strings for any irradiance level. Experimental results with no irradiance agree with the model and show nearly no attenuation for 1 Hz to 100 kHz input frequencies.

  16. IR-images of PV-modules with potential induced degradation (PID) correlated to monitored string power output

    NASA Astrophysics Data System (ADS)

    Buerhop, Claudia; Pickel, Tobias; Blumberg, Tiberius; Adams, Jens; Wrana, Simon; Dalsass, Manuel; Zetzmann, Cornelia; Camus, Christian; Hauch, Jens; Brabec, Christoph J.

    2016-09-01

    Many PV-plants suffer from potential induced degradation (PID) which causes severe power reduction of installed PVmodules. Fast and reliable methods to detect PID and evaluate the impact on the module performance are gaining importance. Drone-assisted IR-inspection is a suitable method. PID affected modules are detected by their characteristic IR-fingerprint, modules with differing number of slightly heated cells occur more frequently at the negative string end. These modules show a degraded IV-curve, lowered Voc and Isc, and electroluminescence (EL)-images with suspicious, dark cells. Also, the measured string power is reduced. For a first quantitative data evaluation the suspicious cell are counted in the IR-images and correlated with the module power. A linear decrease of the module power with increasing number of suspicious cells results. A correlation function for estimating the module power was deduced, which has a mean deviation of less than 7%. This correlation function allows an acceptable approximation of the string power.

  17. Testing and Analysis for Lifetime Prediction of Crystalline Silicon PV Modules Undergoing Degradation by System Voltage Stress: Preprint

    SciTech Connect

    Hacke, P.; Smith, R.; Terwiliger, K.; Glick, S.; Jordan, D.; Johnston, S.; Kempe, M.; Kurtz, S.

    2012-07-01

    Acceleration factors are calculated for crystalline silicon PV modules under system voltage stress by comparing the module power during degradation outdoors to that in accelerated testing at three temperatures and 85% relative humidity. A lognormal analysis is applied to the accelerated lifetime test data considering failure at 80% of the initial module power. Activation energy of 0.73 eV for the rate of failure is determined, and the probability of module failure at an arbitrary temperature is predicted. To obtain statistical data for multiple modules over the course of degradation in-situ of the test chamber, dark I-V measurements are obtained and transformed using superposition, which is found well suited for rapid and quantitative evaluation of potential-induced degradation. It is determined that shunt resistance measurements alone do not represent the extent of power degradation. This is explained with a two-diode model analysis that shows an increasing second diode recombination current and ideality factor as the degradation in module power progresses. Failure modes of the modules stressed outdoors are examined and compared to those stressed in accelerated tests.

  18. Beam Diagnostics Based on AC Modulation of System Parameters

    SciTech Connect

    Michael Tiefenback

    2004-11-10

    To improve the performance of operating accelerators, quantities such as lattice functions, beam transfer functions, betatron frequencies, etc, can be measured turn by turn with beam position monitors or from difference measurements using step changes in system parameters. Spectral measurements in closed orbit machines provide accurate values for some properties. But for open-ended systems and some measurements in closed-orbit machines, periodic modulation can be very useful for obtaining information about the beam line. Using examples from existing machines, we compare and contrast beam based modulation techniques and step function or passive measurements. For example, large amplitude dipole modulation in rings can be used in dedicated exploration of nonlinear optical properties without beam degradation, even allowing for tune spread effects. Low-level modulation can provide real-time system monitoring with no adverse effect on beam users. Examples considered include fully resonant dipole modulation in storage rings such as RHIC (hadrons) and PEP-II (electrons), and the continuous low-level modulation used in the CEBAF recirculating electron linac for real-time feedback to improve availability.

  19. Technical Study Addresses a Key Challenge to Harmonizing U.S. and International PV Module Standards (Fact Sheet)

    SciTech Connect

    Not Available

    2012-07-01

    NREL builds community and industry support by addressing concerns voiced by key standards organizations. Photovoltaic (PV) manufacturers in the United States test the safety of their products using standards developed through consensus processes. Because U.S. PV module safety standards are not aligned with international standards, manufacturers must test their modules twice - and sometimes maintain separate product lines. By meeting with standards organizations such as the Solar ABCs and Underwriters Laboratories (UL), National Renewable Energy Laboratory (NREL) leaders have worked to identify different stakeholders priorities and concerns. UL, specifically, has expressed concern that the international standards do not address all possible risks. For example, new encapsulant materials could soften at high temperatures and frameless modules could slide apart, exposing live electrical parts or allowing glass to fall on a person below. The deformation of a solid material under the influence of mechanical stresses is known as 'creep.' Current module qualification tests are limited to 85 C, whereas modules can, for short times, reach 105 C outdoors. In response to UL's concern, NREL designed and executed an experiment to compare on-sun and accelerated rates of creep for modules fabricated with various encapsulants, including some that have low melting points. Objectives were to (1) evaluate the potential for creep in outdoor exposure, (2) provide guidance on the risks and design needs with thermoplastic materials, and (3) provide a basis for modifying standards to account for materials with potential to creep. The study tested experimental materials with eight representative encapsulants in both outdoor and indoor (chamber) exposure. The study found that modules with materials that were expected to creep did so in the indoor exposure, but not in most outdoor environments and mounting configurations. The results provide a basis for defining an accelerated test needed to

  20. Quantify Degradation Rates and Mechanisms of PV Modules and Systems Installed in Florida Through Comprehensive Experimental and Theoretical Analysis (Poster)

    SciTech Connect

    Sorloaica-Hickman, N.; Davis, K.; Kurtz, S.; Jordan, D.

    2011-02-01

    The economic viability of photovoltaic (PV) technologies is inextricably tied to both the electrical performance and degradation rate of the PV systems, which are the generators of electrical power in PV systems. Over the past 15 years, performance data have been collected on numerous PV systems installed throughout the state of Florida and will be presented.

  1. Framework for a Comparative Accelerated Testing Standard for PV Modules: Preprint

    SciTech Connect

    Kurtz, S.; Wohlgemuth, J.; Yamamichi, M.; Sample, T.; Miller, D.; Meakin, D.; Monokroussos, C.; TamizhMani, M.; Kempe, M.; Jordan, D.; Bosco, N.; Hacke, P.; Bermudez, V.; Kondo, M.

    2013-08-01

    As the photovoltaic industry has grown, the interest in comparative accelerated testing has also grown. Private test labs offer testing services that apply greater stress than the standard qualification tests as tools for differentiating products and for gaining increased confidence in long-term PV investments. While the value of a single international standard for comparative accelerated testing is widely acknowledged, the development of a consensus is difficult. This paper strives to identify a technical basis for a comparative standard.

  2. TRNSYS HYBRID wind diesel PV simulator

    SciTech Connect

    Quinlan, P.J.A.; Mitchell, J.W.; Klein, S.A.; Beckman, W.A.; Blair, N.J.

    1996-12-31

    The Solar Energy Laboratory (SEL) has developed a wind diesel PV hybrid systems simulator, UW-HYBRID 1.0, an application of the TRNSYS 14.2 time-series simulation environment. An AC/DC bus links up to five diesels and wind turbine models, along with PV modules, a battery bank, and an AC/DC converter. Multiple units can be selected. PV system simulations include solar angle and peak power tracking options. Weather data are Typical Meteorological Year data, parametrically generated synthesized data, or external data files. PV performance simulations rely on long-standing SEL-developed algorithms. Loads data are read as scalable time series. Diesel simulations include estimated fuel-use and waste heat output, and are dispatched using a least-cost of fuel strategy. Wind system simulations include varying air density, wind shear and wake effects. Time step duration is user-selectable. UW-HYBRID 1.0 runs in Windows{reg_sign}, with TRNSED providing a customizable user interface. 12 refs., 6 figs.

  3. Enhancing the spin transfer torque in magnetic tunnel junctions by ac modulation

    NASA Astrophysics Data System (ADS)

    Chen, Xiaobin; Zhou, Chenyi; Zhang, Zhaohui; Chen, Jingzhe; Zheng, Xiaohong; Zhang, Lei; Hu, Can-Ming; Guo, Hong

    2017-03-01

    The phenomenon of spin transfer torque (STT) has attracted a great deal of interest due to its promising prospects in practical spintronic devices. In this paper, we report a theoretical investigation of STT in a noncollinear magnetic tunnel junction under ac modulation based on the nonequilibrium Green's-function formalism, and we derive a closed formulation for predicting the time-averaged STT. Using this formulation, the ac STT of a carbon-nanotube-based magnetic tunnel junction is analyzed. Under ac modulation, the low-bias linear (quadratic) dependence of the in-plane (out-of-plane) torque on bias still holds, and the sinθ dependence on the noncollinear angle is maintained. By photon-assisted tunneling, the bias-induced components of the in-plane and out-of-plane torques can be enhanced significantly, about 12 and 75 times, respectively. Our analysis reveals the condition for achieving optimized STT enhancement and suggests that ac modulation is a very effective way for electrical manipulation of STT.

  4. High-resolution ac-pulse modulated electrohydrodynamic jet printing on highly insulating substrates

    NASA Astrophysics Data System (ADS)

    Wei, Chuang; Qin, Hantang; Ramírez-Iglesias, Nakaira A.; Chiu, Chia-Pin; Lee, Yuan-shin; Dong, Jingyan

    2014-04-01

    This paper presents a new high-resolution ac-pulse modulated electrohydrodynamic (EHD)-jet printing technology on highly insulating substrates for drop-on-demand fabrication of electrical features and interconnects using silver nanoink. In traditional EHD-jet printing, the remained charge of the printed droplets changes the electrostatic field distribution and interrupts the follow-on printing behavior, especially for highly insulating substrates which have slow charge decay rates. The residue charge makes the control of EHD-jet printing very challenging for high-resolution continuous features. In this paper, by using modulated ac-pulsed voltage, the EHD-jet printing process switches the charge polarity of the consequent droplets to neutralize the charge on the substrate. The effect of the residue charge is minimized, which enables high-resolution printing of continuous patterns. Moreover, by modulating the pulse frequency, voltage, and duration, the EHD-jet printing behavior can be controlled with respect to printing speed/frequency and droplet size. Printing frequency is directly controlled by the pulse frequency, and the droplet dimension is controlled by the voltage and the duration of the pulse. We demonstrated that ac-pulse modulated EHD-jet printing can overcome the long-predicated charge accumulation problem on highly insulating substrates, and potentially be applied to many flexible electronics applications.

  5. SENP1-modulated sumoylation regulates retinoblastoma protein (RB) and Lamin A/C interaction and stabilization.

    PubMed

    Sharma, P; Kuehn, M R

    2016-12-15

    The retinoblastoma tumor suppressor protein (RB) plays a critical role in cell proliferation and differentiation and its inactivation is a frequent underlying factor in tumorigenesis. While the regulation of RB function by phosphorylation is well studied, proteasome-mediated RB protein degradation is emerging as an important regulatory mechanism. Although our understanding of RB turnover is currently limited, there is evidence that the nuclear lamina filament protein Lamin A/C protects RB from proteasomal degradation. Here we show that SUMO1 conjugation of RB and Lamin A/C is modulated by the SUMO protease SENP1 and that sumoylation of both proteins is required for their interaction. Importantly, this SUMO1-dependent complex protects both RB and Lamin A/C from proteasomal turnover.

  6. Preliminary Investigations on the Effect of Humidity on the Reception of Visible Solar Radiation and the Effect of Humidity and Wind Speed on PV Module Output

    NASA Astrophysics Data System (ADS)

    Zainuddin, Hedzlin; Shaari, Sulaiman; Omar, Ahmad Maliki; Zain, Zainazlan Md.; Soumin, Jonson; Surat, Zainizam

    2010-07-01

    In order to improve the accuracy of methods currently used for characterizing the performance of photovoltaic (PV) arrays in their actual use environment, it is of importance to investigate the effect of ambient variables on the PV module output. Malaysia is a hot and humid country with relative humidity (RH) of 100% during rainfall and wind speed of greater than 4.0 ms-1 occurred about 8.4% in five years time. Therefore, the objective of this paper is to do a preliminary investigation on the effects of RH on the reception of solar radiation and the effect of humidity and wind speed on the PV module output. Outdoor field testing was conducted at Photovoltaic Monitoring Centre (PVMC), Universiti Teknologi MARA, of a BPSX-30U polycrystalline under variation of RH and wind speed separately. From the field testing, it was found that humidity reduced the amount of visible solar radiation reception, while humidity and wind speed both acts as cooling agents that increase the output of a PV module by reducing the module temperature.

  7. Pressure-equalizing PV assembly and method

    DOEpatents

    Dinwoodie, Thomas L.

    2004-10-26

    Each PV assembly of an array of PV assemblies comprises a base, a PV module and a support assembly securing the PV module to a position overlying the upper surface of the base. Vents are formed through the base. A pressure equalization path extends from the outer surface of the PV module, past the PV module, to and through at least one of the vents, and to the lower surface of the base to help reduce wind uplift forces on the PV assembly. The PV assemblies may be interengaged, such as by interengaging the bases of adjacent PV assemblies. The base may include a main portion and a cover and the bases of adjacent PV assemblies may be interengaged by securing the covers of adjacent bases together.

  8. Measurement system for determination of current-voltage characteristics of PV modules

    NASA Astrophysics Data System (ADS)

    Idzkowski, Adam; Walendziuk, Wojciech; Borawski, Mateusz; Sawicki, Aleksander

    2015-09-01

    The realization of a laboratory stand for testing photovoltaic panels is presented here. The project of the laboratory stand was designed in SolidWorks software. The aim of the project was to control the electrical parameters of a PV panel. For this purpose a meter that measures electrical parameters i.e. voltage, current and power, was realized. The meter was created with the use of LabJack DAQ device and LabVIEW software. The presented results of measurements were obtained in different conditions (variable distance from the source of light, variable tilt angle of the panel). Current voltage characteristics of photovoltaic panel were created and all parameters could be detected in different conditions. The standard uncertainties of sample voltage, current, power measurements were calculated. The paper also gives basic information about power characteristics and efficiency of a solar cell.

  9. Temperature-Dependent Light-Stabilized States in Thin-Film PV Modules: Preprint

    SciTech Connect

    Deceglie, Michael G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-09-17

    Thin-film photovoltaic modules are known to exhibit light-induced transient behavior which interferes with accurate and repeatable measurements of power. Typically power measurements are made after a light exposure in order to target a 'light state' of the module that is representative of outdoor performance. Here we show that the concept of a unique light state is poorly defined for both CIGS and CdTe modules. Instead we find that their metastable state after a light exposure can depend on the temperature of the module during the exposure. We observe changes in power as large as 5.8% for a 20 degrees C difference in light exposure temperature. These results lead us to conclude that for applications in which reproducibility and repeatability are critical, module temperature should be tightly controlled during light exposure.

  10. Temperature-Dependent Light-Stabilized States in Thin-Film PV Modules

    SciTech Connect

    Deceglie, Michael G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-06-14

    Thin-film photovoltaic modules are known to exhibit light-induced transient behavior which interferes with accurate and repeatable measurements of power. Typically power measurements are made after a light exposure in order to target a 'light state' of the module that is representative of outdoor performance. Here we show that the concept of a unique light state is poorly defined for both CIGS and CdTe modules. Instead we find that their metastable state after a light exposure can depend on the temperature of the module during the exposure. We observe changes in power as large as 5.8% for a 20 degrees C difference in light exposure temperature. These results lead us to conclude that for applications in which reproducibility and repeatability are critical, module temperature should be tightly controlled during light exposure.

  11. Effects of PV Module Soiling on Glass Surface Resistance and Potential-Induced Degradation

    SciTech Connect

    Hacke, Peter; Button, Patrick; Hendrickson, Alex; Spataru, Sergiu; Glick, Stephen

    2015-06-14

    The goals of the project were: Determine applicability of transmission line method (TLM) to evaluate sheet resistance of soils on module glass;
    Evaluate various soils on glass for changes in surface resistance and their ability to promote potential-induced degradation with humidity (PID);
    Evaluate PID characteristics, rate, and leakage current increases on full-size mc-Si modules associated with a conductive soil on the surface.

  12. Considerations for a Standardized Test for Potential-Induced Degradation of Crystalline Silicon PV Modules (Presentation)

    SciTech Connect

    Hacke, P.

    2012-03-01

    Over the past decade, there have been observations of module degradation and power loss because of the stress that system voltage bias exerts. This results in part from qualification tests and standards note adequately evaluating for the durability of modules to the long-term effects of high voltage bias that they experience in fielded arrays. This talk deals with factors for consideration, progress, and information still needed for a standardized test for degradation due to system voltage stress.

  13. Resistance Inducers Modulate Pseudomonas syringae pv. Tomato Strain DC3000 Response in Tomato Plants

    PubMed Central

    Scalschi, Loredana; Camañes, Gemma; Llorens, Eugenio; Fernández-Crespo, Emma; López, María M.; García-Agustín, Pilar; Vicedo, Begonya

    2014-01-01

    The efficacy of hexanoic acid (Hx) as an inducer of resistance in tomato plants against Pseudomonas syringae pv. tomato DC3000 was previously demonstrated, and the plant response was characterized. Because little is known about the reaction of the pathogen to this effect, the goal of the present work was to determine whether the changes in the plant defence system affect the pathogen behaviour. This work provides the first demonstration of the response of the pathogen to the changes observed in plants after Hx application in terms of not only the population size but also the transcriptional levels of genes involved in quorum sensing establishment and pathogenesis. Therefore, it is possible that Hx treatment attenuates the virulence and survival of bacteria by preventing or diminishing the appearance of symptoms and controlling the growth of the bacteria in the mesophyll. It is interesting to note that the gene transcriptional changes in the bacteria from the treated plants occur at the same time as the changes in the plants. Hx is able to alter bacteria pathogenesis and survival only when it is applied as a resistance inducer because the changes that it promotes in plants affect the bacteria. PMID:25244125

  14. Application of the NREL Test-to-Failure Protocol for PV Modules

    SciTech Connect

    Hacke, P.; Osterwald, C.; Trudell, D.; Terwilliger, K.; Bosco, N.; Oelak, E.; Kurtz, S.

    2011-02-01

    Initial results of application of the NREL Test-to-Failure Protocol are presented and discussed. Six commercially available multicrystalline Si-cell flat-plate modules were subjected to the protocol with controls. The samples were divided among three test sequences, (1) 1000 hours of 85C/85% relative humidity with positive or negative 600 V bias to the active layers with respect to the grounded frame, (2) -40/85C thermal cycling with electrical load at the rated module power, and (3) an alternating sequence between tests (1) and (2). Application of the protocol manifested in the acceleration of degradation mechanisms seen in the field including backsheet delamination, corrosion, bubble formation within the laminate, discoloration of the antireflective coating, and localized heating with degradation of the backsheet as a result of moisture ingress, corrosion, and concentrated current flow. Significant differences in performance after one round of the protocol are seen in damp heat depending on the polarity of the bias applied to the active layer (the short-circuited power leads of the module). The protocol is found to successfully accelerate module degradation mechanisms that have been observed in the field and will help to differentiate the performance and reliability of various module technologies.

  15. Modeling Photovoltaic Module-Level Power Electronics in the System Advisor Model; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    2015-07-01

    Module-level power electronics, such as DC power optimizers, microinverters, and those found in AC modules, are increasing in popularity in smaller-scale photovoltaic (PV) systems as their prices continue to decline. Therefore, it is important to provide PV modelers with guidelines about how to model these distributed power electronics appropriately in PV modeling software. This paper extends the work completed at NREL that provided recommendations to model the performance of distributed power electronics in NREL’s popular PVWatts calculator [1], to provide similar guidelines for modeling these technologies in NREL's more complex System Advisor Model (SAM). Module-level power electronics - such as DC power optimizers, microinverters, and those found in AC modules-- are increasing in popularity in smaller-scale photovoltaic (PV) systems as their prices continue to decline. Therefore, it is important to provide PV modelers with guidelines about how to model these distributed power electronics appropriately in PV modeling software.

  16. Effects of PV Module Soiling on Glass Surface Resistance and Potential-Induced Degradation: Preprint

    SciTech Connect

    Hacke, Peter; Burton, Patrick; Hendrickson, Alex; Spartaru, Sergiu; Glick, Stephen; Terwilliger, Kent

    2015-12-03

    The sheet resistance of three soil types (Arizona road dust, soot, and sea salt) on glass were measured by the transmission line method as a function of relative humidity (RH) between 39% and 95% at 60 degrees C. Sea salt yielded a 3.5 order of magnitude decrease in resistance on the glass surface when the RH was increased over this RH range. Arizona road dust showed reduced sheet resistance at lower RH, but with less humidity sensitivity over the range tested. The soot sample did not show significant resistivity change compared to the unsoiled control. Photovoltaic modules with sea salt on their faces were step-stressed between 25% and 95% RH at 60 degrees C applying -1000 V bias to the active cell circuit. Leakage current from the cell circuit to ground ranged between two and ten times higher than that of the unsoiled controls. Degradation rate of modules with salt on the surface increased with increasing RH and time.

  17. Application of CIS of high-efficiency PV module fabrication. Annual technical progress report, April 1, 1996--March 31, 1997

    SciTech Connect

    Basol, B.; Kapur, V.; Leidholm, C.

    1997-08-01

    This is the Phase II Annual Technical Report of the subcontract titled {open_quotes}Application of CIS to High Efficiency PV Module fabrication.{close_quotes} The general objectives of the program are the development of a novel, non-vacuum process for CIS film deposition, optimization of the various layers forming the CIS device structure, and fabrication of high efficiency submodules. The specific goals of the project are the development of 13% efficient small area cells and 10% efficient submodules using a novel, low-cost CIS deposition approach. During this research period, the authors concentrated their efforts on three different areas of research. Within the National CIS Partnership Program, they participated in the {open_quotes}substrate/Mo interactions{close_quotes} working group and investigated issues such as Na diffusion from the soda-lime glass substrate into the Mo layers and CIS films. It was determined that the Na content within the Mo layers was not a strong function of the nature of the Mo film. However, diffusion through the Mo layers was found to be a function of the Mo film characteristics as well as a very strong function of the CIS growth process. Na was found to be on the grain boundaries in Mo and CIS layers.

  18. Module Safety Issues (Presentation)

    SciTech Connect

    Wohlgemuth, J.

    2012-02-01

    Description of how to make PV modules so that they are less likely to turn into safety hazards. Making modules inherently safer with minimum additional cost is the preferred approach for PV. Safety starts with module design to ensure redundancy within the electrical circuitry to minimize open circuits and proper mounting instructions to prevent installation related ground faults. Module manufacturers must control the raw materials and processes to ensure that that every module is built like those qualified through the safety tests. This is the reason behind the QA task force effort to develop a 'Guideline for PV Module Manufacturing QA'. Periodic accelerated stress testing of production products is critical to validate the safety of the product. Combining safer PV modules with better systems designs is the ultimate goal. This should be especially true for PV arrays on buildings. Use of lower voltage dc circuits - AC modules, DC-DC converters. Use of arc detectors and interrupters to detect arcs and open the circuits to extinguish the arcs.

  19. Application of CIS to high-efficiency PV module fabrication. Phase 3 final technical report

    SciTech Connect

    Basol, B M; Kapur, V K; Leidholm, C R; Halani, A; Roe, R; Norsworthy, G

    1998-08-01

    During this research period, researchers at International Solar Electric Technology (ISET) concentrated their efforts on three different areas of research. Within the National CIS R and D Team, ISET participated in the substrate/Mo interactions working group and investigated issues such as Na diffusion from the soda-lime glass substrate into the Mo layers and CIS films. Researchers determined that the Na content within the Mo layers was not a strong function of the nature of the Mo film. However, they found that diffusion through the Mo layers was a function of the Mo film characteristics as well as a very strong function of the CIS growth process itself. Researchers showed conclusively that the Na resided on the grain boundaries of CIS layers. Another team activity involved evaluation of CdS-free CIS solar cells. ZnO/CIS junctions prepared by the two-stage process showed light-soaking effects. Cells left under illumination improved in efficiency and were similar to the CdS/CIS junctions. After storage in the dark, however, efficiency deteriorated greatly for the ZnO/CIS device, most of the decline coming from the open-circuit voltage values. Much of the effort during this period was spent on developing a low-cost, non-vacuum CIS deposition technique. The method developed involves particulate deposition and formation of precursor layers followed by the conversion of these layers into CIS. Test modules of 40--60 cm{sup 2} were adapted to understand the issues involved in this novel technology. At the present time, the submodule efficiencies are 6--7%. Single-cell efficiencies are in the 10--13% range.

  20. Method and apparatus for pulse width modulation control of an AC induction motor

    NASA Technical Reports Server (NTRS)

    Geppert, Steven (Inventor); Slicker, James M. (Inventor)

    1984-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

  1. Method and apparatus for pulse width modulation control of an AC induction motor

    DOEpatents

    Geppert, Steven; Slicker, James M.

    1984-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

  2. Investigation of bias radiation effect on PV cell measurement

    NASA Astrophysics Data System (ADS)

    Huang, Xuebo; Quan, Chenggen; Chan, Joanne; Ng, Patrick

    2013-06-01

    Photovoltaic (PV) cells are photo-electrical devices that convert light energy directly into electricity through the photovoltaic effect. PV cell assemblies are used to make solar modules employed in a variety of ways ranging from space applications to domestic energy consumption. Characterisation and performance testing of PV cells are critical to the development of PV technologies and growth of the solar industry. As new solar products are being developed, its energy conversion efficiency and other critical parameters must be accurately measured and tested against globally recognised metrological standards. The differential spectral responsivity (DSR) measurement is one of the primary methods for calibrating reference PV cells. This is done by calculating its spectral responsivities through measuring the AC short-circuit current produced by a PV cell under a modulated monochromatic radiation and different levels of steady-state broadband bias light radiation. It is observed that different types of bias light source will produce different signal-to-noise levels and significantly influence measurement accuracy. This paper aims to investigate the noise sources caused by different types of bias light sources (e.g. xenon arc and tungsten-halogen lamps) and the relevant measurement uncertainties so as to propose a guideline for selection of bias light source which can improve the signal-to-noise level and measurement uncertainty. The DSRs of the PV cells are measured using a commercial DSR measurement system under different levels of bias radiation from 0 to 1 kWm-2. The data analysis and uncertainty evaluation are presented in this paper using experimental data and mathematical tools.

  3. Research Leading to High Throughput Manufacturing of Thin-Film CdTe PV Modules: Annual Subcontract Report, September 2004--September 2005

    SciTech Connect

    Powell, R. C.

    2006-04-01

    Specific overall objectives of this subcontract are improvement in baseline field performance of manufactured CdTe PV modules while reducing environmental, health and safety risk in the manufacturing environment. Project objectives focus on four broad categories: (1) development of advanced front-contact window layers, (2) improved semiconductor film deposition, (3) development of improved accelerated life test procedures that indicate baseline field performance, and (4) reduction of cadmium-related environmental, health and safety risks. First Solar has significantly increased manufacturing capacity from less than 2 MW/yr to more than 20 MW/yr, while increasing the average module total-area power conversion efficiency from 7% to >9%. First Solar currently manufactures and sells 50-65-W thin-film CdTe PV modules at a rate of about 1.9 MW/month. Sales backlog (booked sales less current inventory divided by production rate) is more than a year. First Solar is currently building new facilities and installing additional equipment to increase production capacity by 50 MW/yr; the additional capacity is expected to come on line in the third quarter of 2006.

  4. Study of 1 MW PV array at the Kennedy Space Center

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.; Schneller, Eric; Martin, Wayne R.; Dhere, Ramesh G.

    2016-09-01

    FP and L has deployed a 1 MW c-Si in a fenced compound at the Kennedy Space Center. Two 500 kW inverters located in an elevated and air-conditioned enclosure convert direct current (DC) to alternating current (AC). The generated power, DC and AC voltages and currents are measured and recorded. Charts of variation of PV parameters are generated for analyses. The generated power is also tabulated and reported on periodic basis. Infrared and visual images of the array, sections of the array, and of individual modules from the front and back are recorded periodically. Any interruption of power generation are recorded. The dust and corrosion on screws and frame were observed in a few modules. The temperature of active area of module is higher than that of metallic support and frame probably because of conduction of the heat by the heavy metallic structure. The 1-MW PV array is operating normally without signs of excessive degradation except for collection of dust towards the bottom of a few modules. Since these modules were not washed periodically and any cleaning was by rain. Thus the collection of dust towards the bottom of modules can be understood and does not pose a serious problem. Corrosion on screws and frame were observed in a few modules. This study if continued over a long time, will serve to follow the behavior of this reasonable size PV Plant.

  5. A LOV protein modulates the physiological attributes of Xanthomonas axonopodis pv. citri relevant for host plant colonization.

    PubMed

    Kraiselburd, Ivana; Alet, Analía I; Tondo, María Laura; Petrocelli, Silvana; Daurelio, Lucas D; Monzón, Jesica; Ruiz, Oscar A; Losi, Aba; Orellano, Elena G

    2012-01-01

    Recent studies have demonstrated that an appropriate light environment is required for the establishment of efficient vegetal resistance responses in several plant-pathogen interactions. The photoreceptors implicated in such responses are mainly those belonging to the phytochrome family. Data obtained from bacterial genome sequences revealed the presence of photosensory proteins of the BLUF (Blue Light sensing Using FAD), LOV (Light, Oxygen, Voltage) and phytochrome families with no known functions. Xanthomonas axonopodis pv. citri is a Gram-negative bacterium responsible for citrus canker. The in silico analysis of the X. axonopodis pv. citri genome sequence revealed the presence of a gene encoding a putative LOV photoreceptor, in addition to two genes encoding BLUF proteins. This suggests that blue light sensing could play a role in X. axonopodis pv. citri physiology. We obtained the recombinant Xac-LOV protein by expression in Escherichia coli and performed a spectroscopic analysis of the purified protein, which demonstrated that it has a canonical LOV photochemistry. We also constructed a mutant strain of X. axonopodis pv. citri lacking the LOV protein and found that the loss of this protein altered bacterial motility, exopolysaccharide production and biofilm formation. Moreover, we observed that the adhesion of the mutant strain to abiotic and biotic surfaces was significantly diminished compared to the wild-type. Finally, inoculation of orange (Citrus sinensis) leaves with the mutant strain of X. axonopodis pv. citri resulted in marked differences in the development of symptoms in plant tissues relative to the wild-type, suggesting a role for the Xac-LOV protein in the pathogenic process. Altogether, these results suggest the novel involvement of a photosensory system in the regulation of physiological attributes of a phytopathogenic bacterium. A functional blue light receptor in Xanthomonas spp. has been described for the first time, showing an important

  6. Failure and Degradation Modes of PV modules in a Hot Dry Climate: Results after 4 and 12 years of field exposure

    NASA Astrophysics Data System (ADS)

    Mallineni, Jaya krishna

    This study evaluates two photovoltaic (PV) power plants based on electrical performance measurements, diode checks, visual inspections and infrared scanning. The purpose of this study is to measure degradation rates of performance parameters (Pmax, Isc, Voc, Vmax, Imax and FF) and to identify the failure modes in a "hot-dry desert" climatic condition along with quantitative determination of safety failure rates and reliability failure rates. The data obtained from this study can be used by module manufacturers in determining the warranty limits of their modules and also by banks, investors, project developers and users in determining appropriate financing or decommissioning models. In addition, the data obtained in this study will be helpful in selecting appropriate accelerated stress tests which would replicate the field failures for the new modules and would predict the lifetime for new PV modules. The study was conducted at two, single axis tracking monocrystalline silicon (c-Si) power plants, Site 3 and Site 4c of Salt River Project (SRP). The Site 3 power plant is located in Glendale, Arizona and the Site 4c power plant is located in Mesa, Arizona both considered a "hot-dry" field condition. The Site 3 power plant has 2,352 modules (named as Model-G) which was rated at 250 kW DC output. The mean and median degradation of these 12 years old modules are 0.95%/year and 0.96%/year, respectively. The major cause of degradation found in Site 3 is due to high series resistance (potentially due to solder-bond thermo-mechanical fatigue) and the failure mode is ribbon-ribbon solder bond failure/breakage. The Site 4c power plant has 1,280 modules (named as Model-H) which provide 243 kW DC output. The mean and median degradation of these 4 years old modules are 0.96%/year and 1%/year, respectively. At Site 4c, practically, none of the module failures are observed. The average soiling loss is 6.9% in Site 3 and 5.5% in Site 4c. The difference in soiling level is attributed

  7. Electron mobility characterization in OLEDs from ac small signal optical modulation

    NASA Astrophysics Data System (ADS)

    Mu, Haichuan; Reddy, Indrani; Hunt, John; Severs, Phillip; Patil, Shirish

    2010-05-01

    This paper investigates the field dependence of electron mobility in tris(8-hydroxyquinolinato)aluminium (Alq3) and bathocuproine (BCP) through ac small signal optical modulation on green light (ITO/PEDOT/NPD/Alq3/Ba/Ag) and blue light (ITO/PEDOT/NPD/BCP/Alq3/Ba/Ag) OLED. The electroluminescence (EL) transient time delay for the blue light OLED is much longer than for the green one. The electron mobility in BCP was extracted based on a Poole-Frenkel-like equation and EL transient time delay measurement, which is in the range (7-9) × 10-8 cm2 V-1 s-1 at an external electric field of 1530-1830 (V cm-1)1/2, comparable to the results from other published reports (Muckl et al 2000 Synth. Met. 111-112 91; Barth et al 2001 J. Appl. Phys. 89 3711; Nakamura H et al 1996 Int. Symp. on Inorganic and Organic Electroluminescence ed R H Mauch and H-E Gumlich (Berlin: Wissenschaft und Technik) p 95; Xie et al 2002 Appl. Phys. Lett. 80 1477). The difference in EL transient time delay and electron mobility for green and blue light OLEDs was demonstrated by the results of direct modulation. The electron transit time shows similar field dependence in both Alq3 layers in green and blue OLEDs. Unlike Alq3, the field dependence of electron mobility in BCP did not fit the conventional organic semiconductor characteristics μ∞exp(βE1/2), and the excitons formation at the NPD/BCP interface for the blue OLEDs was demonstrated through the EL spectrum.

  8. Outdoor PV Degradation Comparison

    SciTech Connect

    Jordan, D. C.; Smith, R. M.; Osterwald, C. R.; Gelak, E.; Kurtz, S. R.

    2011-02-01

    As photovoltaic (PV) penetration of the power grid increases, it becomes vital to know how decreased power output; may affect cost over time. In order to predict power delivery, the decline or degradation rates must be determined; accurately. At the Performance and Energy Rating Testbed (PERT) at the Outdoor Test Facility (OTF) at the; National Renewable Energy Laboratory (NREL) more than 40 modules from more than 10 different manufacturers; were compared for their long-term outdoor stability. Because it can accommodate a large variety of modules in a; limited footprint the PERT system is ideally suited to compare modules side-by-side under the same conditions.

  9. High Step-Up DC—DC Converter for AC Photovoltaic Module with MPPT Control

    NASA Astrophysics Data System (ADS)

    Sundar, Govindasamy; Karthick, Narashiman; Rama Reddy, Sasi

    2014-08-01

    This paper presents the high gain step-up BOOST converter which is essential to step up the low output voltage from PV panel to the high voltage according to the requirement of the application. In this paper a high gain BOOST converter with coupled inductor technique is proposed with the MPPT control. Without extreme duty ratios and the numerous turns-ratios of a coupled inductor this converter achieves a high step-up voltage-conversion ratio and the leakage energy of the coupled inductor is efficiently recycled to the load. MPPT control used to extract the maximum power from PV panel by controlling the Duty ratio of the converter. The PV panel, BOOST converter and the MPPT are modeled using Sim Power System blocks in MATLAB/SIMULINK environment. The prototype model of the proposed converter has been implemented with the maximum measured efficiency is up to 95.4% and full-load efficiency is 93.1%.

  10. Photovoltaic power modules for NASA's manned Space Station

    NASA Technical Reports Server (NTRS)

    Tatro, C. A.

    1988-01-01

    The capability and the safety of manned spacecraft are largely dependent upon reliable electric power systems. Two similar space power systems able to survive the low earth orbit environment, are being considered for NASA's Manned Space Station (SS), scheduled to begin operation in the mid 1990's. The Space Station Electric Power System (EPS) is composed of Photovoltaic (PV) Power Modules, Solar Dynamic (SD) Power Modules, and the Power Management and Distribution (PMAD) System. One EPS configuration will deliver 37.5 kW of PV based, utility grade, ac power to SS users. A second 75 kWe PV based EPS option is also being considered for SS deployment. The two EPS options utilize common modules and differ only in the total number of PV Power Modules used. Each PV Power Module supplies 18.75 kWe of ac power and incorporates its own energy storage and thermal control. The general requirements and the current preliminary design configuration of the Space Station PV Power Modules are examined.

  11. Photovoltaic power modules for NASA's manned space station

    NASA Technical Reports Server (NTRS)

    Tatro, Charles A.

    1987-01-01

    The capability and the safety of manned spacecraft are largely dependent upon reliable electric power systems. Two similar space power systems able to survive the low Earth orbit environment, are being considered for NASA's Manned Space Station (SS), scheduled to begin operation in the mid 1990's. The Space Station Electric Power System (EPS) is composed of Photovoltaic (PV) Power Modules, Solar Dynamic (SD) Power Modules, and the Power Management and Distribution (PMAD) System. One EPS configuration will deliver 37.5 kW of PV based, utility grade, ac power to SS users. A second 75 kWe PV based EPS option is also being considered for SS deployment. The two EPS options utilize common modules and differ only in the total number of PV Power Modules used. Each PV Power Module supplies 18.75 kWe of ac power and incorporates its own energy storage and thermal control. The general requirements and the current preliminary design configuration of the Space Station PV Power Modules are examined.

  12. Photovoltaic (PV) Power Systems for Enhancing Energy Security

    DTIC Science & Technology

    2012-05-24

    Energy and Environment Technology Transition – Supporting DoD Readiness, Sustainability, and the Warfighter Photovoltaic (PV) Power Systems for...to 00-00-2012 4. TITLE AND SUBTITLE Photovoltaic (PV) Power Systems for Enhancing Energy Security 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...use of 235W solar panels Note [2] System AC Rating based upon typical .77 conversion factor from DC power to AC power ConsiderationNo. PV LAYOUT OPTION

  13. An AC modulated near infrared gain calibration system for a "Violin-Mode" transimpedance amplifier, intended for advanced LIGO suspensions.

    PubMed

    Lockerbie, N A; Tokmakov, K V

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which a 40 kg test-mass/mirror is suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation, and a "tall-thin" rectangular silicon photodiode detector, which together were to bracket the fibre under test. The photodiode was positioned so as to be sensitive (primarily) to transverse "Violin-Mode" vibrations of such a fibre, via the oscillatory movement of the shadow cast by the fibre, as this moved across the face of the detector. In this prototype shadow sensing system the photodiode was interfaced to a purpose-built transimpedance amplifier, this having both AC and DC outputs. A quasi-static calibration was made of the sensor's DC responsivity, i.e., incremental rate of change of output voltage versus fibre position, by slowly scanning a fused-silica fibre sample transversely through the illuminating beam. The work reported here concerns the determination of the sensor's more important AC (Violin-Mode) responsivity. Recognition of the correspondence between direct AC modulation of the source, and actual Violin-Mode signals, and of the transformative role of the AC/DC gain ratio for the amplifier, at any modulation frequency, f, resulted in the construction of the AC/DC calibration source described here. A method for determining in practice the transimpedance AC/DC gain ratio of the photodiode and amplifier, using this source, is illustrated by a specific numerical example, and the gain ratio for the prototype sensing system is reported over the frequency range 1 Hz-300 kHz. In fact, a maximum DC responsivity of 1.26 kV.m(-1) was measured using the prototype photodiode sensor and amplifier discussed here. Therefore, the measured AC/DC transimpedance gain

  14. An AC modulated near infrared gain calibration system for a "Violin-Mode" transimpedance amplifier, intended for advanced LIGO suspensions

    NASA Astrophysics Data System (ADS)

    Lockerbie, N. A.; Tokmakov, K. V.

    2016-07-01

    The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which a 40 kg test-mass/mirror is suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) radiation, and a "tall-thin" rectangular silicon photodiode detector, which together were to bracket the fibre under test. The photodiode was positioned so as to be sensitive (primarily) to transverse "Violin-Mode" vibrations of such a fibre, via the oscillatory movement of the shadow cast by the fibre, as this moved across the face of the detector. In this prototype shadow sensing system the photodiode was interfaced to a purpose-built transimpedance amplifier, this having both AC and DC outputs. A quasi-static calibration was made of the sensor's DC responsivity, i.e., incremental rate of change of output voltage versus fibre position, by slowly scanning a fused-silica fibre sample transversely through the illuminating beam. The work reported here concerns the determination of the sensor's more important AC (Violin-Mode) responsivity. Recognition of the correspondence between direct AC modulation of the source, and actual Violin-Mode signals, and of the transformative role of the AC/DC gain ratio for the amplifier, at any modulation frequency, f, resulted in the construction of the AC/DC calibration source described here. A method for determining in practice the transimpedance AC/DC gain ratio of the photodiode and amplifier, using this source, is illustrated by a specific numerical example, and the gain ratio for the prototype sensing system is reported over the frequency range 1 Hz-300 kHz. In fact, a maximum DC responsivity of 1.26 kV.m-1 was measured using the prototype photodiode sensor and amplifier discussed here. Therefore, the measured AC/DC transimpedance gain ratio

  15. Electric Double Layer Capacitor (EDLC) based Mismatching Losses Reduction under Fast-Shaded Conditions of PV Modules

    NASA Astrophysics Data System (ADS)

    Syafaruddin; Tanaka, Yasuyuki; Karatepe, Engin; Hiyama, Takashi

    Fast-moving irradiance condition is one of problems that need to be solved in the non-stationary conventional maximum power point (MPP) trackers of PV system. Under sudden irradiance changes, the output power is changed drastically that leads to the shifting in MPP voltage. Conventional MPP algorithms may start continuously to search for finding the optimum point. However, suddenly another shadow can occur prior to complete removing of previous shadow. Continuing the tracking process under this condition will cause to lose energy. This paper presents the electric double layer capacitor (EDLC) as the power compensation method for improving the maximum power transfer of PV system under short-term period of shading. Several scenarios are tested in this work by measurement the percentage of power compensation, for instance the effect of capacitor size to the period of shading, the effects of shading period to the level shading intensity and cell temperature. This paper is directly purposed to reduce the power losses for moving objects powered by solar energy, such as solar car and solar boat systems.

  16. Ballasted photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Danning, Matt [Oakland, CA

    2011-11-29

    A photovoltaic (PV) module assembly including a PV module and a ballast tray. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes an arm. The ballast tray is adapted for containing ballast and is removably associated with the PV module in a ballasting state where the tray is vertically under the PV laminate and vertically over the arm to impede overt displacement of the PV module. The PV module assembly can be installed to a flat commercial rooftop, with the PV module and the ballast tray both resting upon the rooftop. In some embodiments, the ballasting state includes corresponding surfaces of the arm and the tray being spaced from one another under normal (low or no wind) conditions, such that the frame is not continuously subjected to a weight of the tray.

  17. Progress & Frontiers in PV Performance

    SciTech Connect

    Deline, Chris; DiOrio, Nick; Jordan, Dirk; Toor, Fatima

    2016-09-12

    PowerPoint slides for a presentation given at Solar Power International 2016. Presentation includes System Advisor Model (SAM) introduction and battery modeling, bifacial PV modules and modeling, shade modeling and module level power electronics (MLPE), degradation rates, and PVWatts updates and validation.

  18. System and method for design and optimization of grid connected photovoltaic power plant with multiple photovoltaic module technologies

    DOEpatents

    Thomas, Bex George; Elasser, Ahmed; Bollapragada, Srinivas; Galbraith, Anthony William; Agamy, Mohammed; Garifullin, Maxim Valeryevich

    2016-03-29

    A system and method of using one or more DC-DC/DC-AC converters and/or alternative devices allows strings of multiple module technologies to coexist within the same PV power plant. A computing (optimization) framework estimates the percentage allocation of PV power plant capacity to selected PV module technologies. The framework and its supporting components considers irradiation, temperature, spectral profiles, cost and other practical constraints to achieve the lowest levelized cost of electricity, maximum output and minimum system cost. The system and method can function using any device enabling distributed maximum power point tracking at the module, string or combiner level.

  19. Terrestrial Concentrator PV Modules Based on GaInP/GaAs/Ge TJ Cells and Minilens Panels

    SciTech Connect

    Rumyantsev, V. D.; Sadchikov, N. A.; Chalov, A. E.; Ionova, E. A.; Friedman, D. J.; Glenn, G.

    2006-01-01

    This paper is a description of research activity in the field of cost-effective modules realizing the concept of very high solar concentration with small-aperture area Fresnel lenses and multijunction III-V cells. Structural simplicity and 'all-glass' design are the guiding principles of the corresponding development. The advanced concentrator modules are made with silicone Fresnel lens panels (from 8 up to 144 lenses, each lens is 4 times 4 cm{sup 2} in aperture area) with composite structure. GaInP/GaAs/Ge triple-junction cells with average efficiencies of 31.1 and 34.7% at 1000 suns were used for the modules. Conversion efficiency as high as 26.3% has been measured indoors in a test module using a newly developed large-area solar simulator.

  20. Application of CIS to high-efficiency PV module fabrication. Annual technical progress report, April 1, 1995--March 31, 1996

    SciTech Connect

    Basol, B.; Kapur, V.; Leidholm, C.; Halani, A.

    1996-06-01

    The authors investigated the interactions between the soda-lime glass substrate, the Mo contract film and the CIS absorber layer. Excessive Na diffusion through the Mo layer was found to be the reason for excessive interaction between the substrate and the CIS layers obtained by the H{sub 2}Se selenization technique. This chemical interaction influenced the stoichiometric uniformity of the absorbers. Addition of Ga into the CIS layers by the two-stage selenization technique yielded graded absorber structures with higher Ga content near the Mo/absorber interface. Gallium was later diffused through the absorber film by a high-temperature annealing step, and large bandgap alloys were obtained. Solar cells with active-area efficiencies of close to 12% were fabricated on these CIGS layers. Sulfur addition experiments were also carried out during this period. By controlling the Se and S availability to the precursors during the reaction step of the process, various S profiles were obtained in high-bandgap absorber layers. The highest-efficiency cell made on S-containing absorbers was about 10% efficient. A low-cost, non-vacuum technique was successfully developed for CIS film growth. Layers prepared using this novel approach were used for solar-cell and submodule fabrication. Solar cells with active-area efficiencies around 13% were demonstrated; submodules with efficiencies above 8% were also fabricated. These results represent the best PV devices ever produced on CIS layers obtained by a non-vacuum technique.

  1. A control strategy for PV stand-alone applications

    NASA Astrophysics Data System (ADS)

    Slouma, S.; Baccar, H.

    2015-04-01

    This paper proposes a stand-alone photovoltaic (PV) system study in domestic applications. Because of the decrease in power of photovoltaic module as a consequence of changes in solar radiation and temperature which affect the photovoltaic module performance, the design and control of DC-DC buck converter was proposed for providing power to the load from a photovoltaic source.In fact, the control of this converter is carried out with integrated MPPT (Maximum Power Point Tracking) algorithm which ensures a maximum energy generated by the PV arrays. Moreover, the output stage is composed by a battery energy storage system, dc-ac inverter, LCL filter which enables higher efficiency, low distortion ac waveforms and low leakage currents. The control strategy adopted is cascade control composed by two regulation loops.Simulations performed with PSIM software were able to validate the control system.The realization and testing of the photovoltaic system were achieved in the Photovoltaic laboratory of the Centre for Research and Energy Technologies at the Technopark Borj Cedria. Experimental results verify the effeciency of the proposed system.

  2. Review of Photovoltaic Energy Production Using Thin Film Modules

    NASA Astrophysics Data System (ADS)

    Gessert, Timothy

    2011-04-01

    It is now widely accepted that thin-film photovoltaic (PV) devices will be important contributors of new US electricity generation. The annual production of PV devices needed to meet conservative U.S. Department of Energy goals for 2050 represents ˜100 square miles of active module area (20 GW), or ˜200 times the total area of photovoltaic modules installed in the US by 2004. However, if the rate of growth observed in PV module production for the past eight years continues, 100 square miles of annual US PV production could be achieved as early as 2018. Further, the amount PV installed by 2036 could generate the entire 2004 US Total Energy Consumption (˜100 Quadrillion BTU's, i.e., the combined energy consumed in the US from petroleum, coal, natural gas, nuclear, and all renewable sources). Regardless of what assumptions are made, PV represents a significant future market for related materials and technologies. This talk will discuss thin-film PV devices within the context of the major PV technologies in production today, and indicate areas where improved material and device understanding would be beneficial. This work was performed with the support of US Department of Energy Contract No. DE-AC36-08-GO28308. This abstract is subject to government rights.

  3. Improved methods for the measurement and modeling of PV module and system performance for all operating conditions

    SciTech Connect

    King, D.L.

    1995-11-01

    The objective of this work was to develop improved performance model for modules and systems for for all operating conditions for use in module specifications, system and BOS component design, and system rating or monitoring. The approach taken was to identify and quantify the influence of dominant factors of solar irradiance, cell temperature, angle-of-incidence; and solar spectrum; use outdoor test procedures to separate the effects of electrical, thermal, and optical performance; use fundamental cell characteristics to improve analysis; and combine factors in simple model using the common variables.

  4. Charge transport and ac response under light illumination in gate-modulated DNA molecular junctions.

    PubMed

    Zhang, Yan; Zhu, Wen-Huan; Ding, Guo-Hui; Dong, Bing; Wang, Xue-Feng

    2015-05-22

    Using a two-strand tight-binding model and within nonequilibrium Green's function approach, we study charge transport through DNA sequences (GC)NGC and (GC)1(TA)NTA (GC)3 sandwiched between two Pt electrodes. We show that at low temperature DNA sequence (GC)NGC exhibits coherent charge carrier transport at very small bias, since the highest occupied molecular orbital in the GC base pair can be aligned with the Fermi energy of the metallic electrodes by a gate voltage. A weak distance dependent conductance is found in DNA sequence (GC)1(TA)NTA (GC)3 with large NTA. Different from the mechanism of thermally induced hopping of charges proposed by the previous experiments, we find that this phenomenon is dominated by quantum tunnelling through discrete quantum well states in the TA base pairs. In addition, ac response of this DNA junction under light illumination is also investigated. The suppression of ac conductances of the left and right lead of DNA sequences at some particular frequencies is attributed to the excitation of electrons in the DNA to the lead Fermi surface by ac potential, or the excitation of electrons in deep DNA energy levels to partially occupied energy levels in the transport window. Therefore, measuring ac response of DNA junctions can reveal a wealth of information about the intrinsic dynamics of DNA molecules.

  5. Quantitatively probing the magnetic behavior of individual nanoparticles by an AC field-modulated magnetic force microscopy.

    PubMed

    Li, Xiang; Lu, Wei; Song, Yiming; Wang, Yuxin; Chen, Aiying; Yan, Biao; Yoshimura, Satoru; Saito, Hitoshi

    2016-03-02

    Despite decades of advances in magnetic imaging, obtaining direct, quantitative information with nanometer scale spatial resolution remains an outstanding challenge. Current approaches, for example, Hall micromagnetometer and nitrogen-vacancy magnetometer, are limited by highly complex experimental apparatus and a dedicated sample preparation process. Here we present a new AC field-modulated magnetic force microscopy (MFM) and report the local and quantitative measurements of the magnetic information of individual magnetic nanoparticles (MNPs), which is one of the most iconic objects of nanomagnetism. This technique provides simultaneously a direct visualization of the magnetization process of the individual MNPs, with spatial resolution and magnetic sensitivity of about 4.8 nm and 1.85 × 10(-20) A m(2), respectively, enabling us to separately estimate the distributions of the dipolar fields and the local switching fields of individual MNPs. Moreover, we demonstrate that quantitative magnetization moment of individual MNPs can be routinely obtained using MFM signals. Therefore, it underscores the power of the AC field-modulated MFM for biological and biomedical applications of MNPs and opens up the possibility for directly and quantitatively probing the weak magnetic stray fields from nanoscale magnetic systems with superior spatial resolution.

  6. Quantitatively probing the magnetic behavior of individual nanoparticles by an AC field-modulated magnetic force microscopy

    PubMed Central

    Li, Xiang; Lu, Wei; Song, Yiming; Wang, Yuxin; Chen, Aiying; Yan, Biao; Yoshimura, Satoru; Saito, Hitoshi

    2016-01-01

    Despite decades of advances in magnetic imaging, obtaining direct, quantitative information with nanometer scale spatial resolution remains an outstanding challenge. Current approaches, for example, Hall micromagnetometer and nitrogen-vacancy magnetometer, are limited by highly complex experimental apparatus and a dedicated sample preparation process. Here we present a new AC field-modulated magnetic force microscopy (MFM) and report the local and quantitative measurements of the magnetic information of individual magnetic nanoparticles (MNPs), which is one of the most iconic objects of nanomagnetism. This technique provides simultaneously a direct visualization of the magnetization process of the individual MNPs, with spatial resolution and magnetic sensitivity of about 4.8 nm and 1.85 × 10−20 A m2, respectively, enabling us to separately estimate the distributions of the dipolar fields and the local switching fields of individual MNPs. Moreover, we demonstrate that quantitative magnetization moment of individual MNPs can be routinely obtained using MFM signals. Therefore, it underscores the power of the AC field-modulated MFM for biological and biomedical applications of MNPs and opens up the possibility for directly and quantitatively probing the weak magnetic stray fields from nanoscale magnetic systems with superior spatial resolution. PMID:26932357

  7. Quantitatively probing the magnetic behavior of individual nanoparticles by an AC field-modulated magnetic force microscopy

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Lu, Wei; Song, Yiming; Wang, Yuxin; Chen, Aiying; Yan, Biao; Yoshimura, Satoru; Saito, Hitoshi

    2016-03-01

    Despite decades of advances in magnetic imaging, obtaining direct, quantitative information with nanometer scale spatial resolution remains an outstanding challenge. Current approaches, for example, Hall micromagnetometer and nitrogen-vacancy magnetometer, are limited by highly complex experimental apparatus and a dedicated sample preparation process. Here we present a new AC field-modulated magnetic force microscopy (MFM) and report the local and quantitative measurements of the magnetic information of individual magnetic nanoparticles (MNPs), which is one of the most iconic objects of nanomagnetism. This technique provides simultaneously a direct visualization of the magnetization process of the individual MNPs, with spatial resolution and magnetic sensitivity of about 4.8 nm and 1.85 × 10‑20 A m2, respectively, enabling us to separately estimate the distributions of the dipolar fields and the local switching fields of individual MNPs. Moreover, we demonstrate that quantitative magnetization moment of individual MNPs can be routinely obtained using MFM signals. Therefore, it underscores the power of the AC field-modulated MFM for biological and biomedical applications of MNPs and opens up the possibility for directly and quantitatively probing the weak magnetic stray fields from nanoscale magnetic systems with superior spatial resolution.

  8. XopN-T3SS effector of Xanthomonas axonopodis pv. punicae localizes to the plasma membrane and modulates ROS accumulation events during blight pathogenesis in pomegranate.

    PubMed

    Kumar, Rishikesh; Soni, Madhvi; Mondal, Kalyan K

    2016-12-01

    Bacterial blight caused by Xanthomonas axonopodis pv. punicae (Xap) is a major disease of pomegranate. Xap secretes effector proteins via type III secretion system (T3SS) to suppress pathogen-associated molecular pattern (PAMP)-triggered plant immunity (PTI). Previously we reported that XopN, a conserved effector of Xap, modulate in planta bacterial growth, and blight disease. In continuation to that here we report the deletion of XopN from Xap caused higher accumulation of reactive oxygen species (ROS) including H2O2 and O2(-). We quantitatively assessed the higher accumulation of H2O2 in pomegranate leaves infiltrated with Xap ΔxopN compared to Xap wild-type. We analysed that 1.5 to 3.3 fold increase in transcript expression of ROS and flg22-inducible genes, namely FRK1, GST1, WRKY29, PR1, PR2 and PR5 in Arabidopsis when challenged with Xap ΔxopN; contrary, the up-regulation of all the genes were compromised when challenged with either Xap wild-type or Xap ΔxopN+xopN. Further, we demonstrated the plasma-membrane based localization of XopN protein both in its natural and experimental hosts. All together, the present study suggested that XopN-T3SS effector of Xap gets localized in the plasma membrane and suppresses ROS-mediated early defense responses during blight pathogenesis in pomegranate.

  9. Module Thirteen: Series AC RLC Circuits and Resonance; Basic Electricity and Electronics Individualized Learning System.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    In this module the student will combine RL (resistive-inductance) and RC (resistive-capacitive) circuits and learn some of the phenomena which result. The module is divided into four lessons: solving RLC (resistive-inductance-capacitive) circuits, resonant frequency in series circuits, conditions of series resonance, and experiments with series…

  10. Module Fourteen: Parallel AC Resistive-Reactive Circuits; Basic Electricity and Electronics Individualized Learning System.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    In this module the student will learn about parallel RL (resistive-inductance), RC (resistive-capacitive), and RCL (resistive-capacitive-inductance) circuits and the conditions that exist at resonance. The module is divided into six lessons: solving for quantities in RL parallel circuits; variational analysis of RL parallel circuits; parallel RC…

  11. Determination of Parameters of PV Concentrating System With Heliostat

    NASA Astrophysics Data System (ADS)

    Vardanyan, R.; Norsoyan, A.; Dallakyan, V.

    2010-10-01

    The structure of PV concentrating system with heliostat is analyzed. The mathematical model of system consisting of PV concentrating module and heliostat is developed. With the use of developed mathematical model the optimal parameters of the system are determined. The results of this work can be used during the design of PV concentrating systems with heliostats.

  12. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    SciTech Connect

    Choi, Woo-Young; Lai, Jih-Sheng

    2010-04-15

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC-DC converter and a single-phase full-bridge DC-AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC-DC converter. The proposed step-up DC-DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC-DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC-DC converter and the DC-AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current. (author)

  13. Arabidopsis AtERF014 acts as a dual regulator that differentially modulates immunity against Pseudomonas syringae pv. tomato and Botrytis cinerea

    PubMed Central

    Zhang, Huijuan; Hong, Yongbo; Huang, Lei; Li, Dayong; Song, Fengming

    2016-01-01

    ERF transcription factors play critical roles in plant immune responses. Here, we report the function of AtERF014, a nucleus-localized transcriptional activator, in Arabidopsis immunity. Expression of AtERF014 was induced by Pseudomonas syringae pv. tomato (Pst) and Botrytis cinerea (Bc). AtERF014-overexpressing (OE) plants displayed increased Pst resistance but decreased Bc resistance, whereas AtERF014-RNAi plants exhibited decreased Pst resistance but increased Bc resistance. After Pst infection, expression of salicylic acid (SA)-responsive genes AtPR1 and AtPR5 in AtERF014-OE plants and of a jasmonic acid/ethylene-responsive gene AtPDF1.2 in AtERF014-RNAi plants was intensified but expression of AtPDF1.2 in AtERF014-OE plants and of AtPR1 and AtPR5 in AtERF014-RNAi plants was weakened. After Bc infection, expression of AtPR1 and AtPR5 in AtERF014-OE plants was attenuated but expression of AtPR1, AtPR5 and AtPDF1.2 in AtERF014-RNAi plants was strengthened. Pathogen- and flg22-induced ROS burst, expression of PTI genes and SA-induced defense were partially suppressed in AtERF014-RNAi plants, whereas pathogen-induced ROS and flg22-induced immune response were strengthened in AtER014-OE plants. Altered expression of AtERR014 affected expression of pectin biosynthetic genes and pectin content in AtERF014-RNAi plants was decreased. These data demonstrate that AtERF014 acts as a dual regulator that differentially modulates immunity against Pst and Bc in Arabidopsis. PMID:27445230

  14. Arabidopsis AtERF014 acts as a dual regulator that differentially modulates immunity against Pseudomonas syringae pv. tomato and Botrytis cinerea.

    PubMed

    Zhang, Huijuan; Hong, Yongbo; Huang, Lei; Li, Dayong; Song, Fengming

    2016-07-22

    ERF transcription factors play critical roles in plant immune responses. Here, we report the function of AtERF014, a nucleus-localized transcriptional activator, in Arabidopsis immunity. Expression of AtERF014 was induced by Pseudomonas syringae pv. tomato (Pst) and Botrytis cinerea (Bc). AtERF014-overexpressing (OE) plants displayed increased Pst resistance but decreased Bc resistance, whereas AtERF014-RNAi plants exhibited decreased Pst resistance but increased Bc resistance. After Pst infection, expression of salicylic acid (SA)-responsive genes AtPR1 and AtPR5 in AtERF014-OE plants and of a jasmonic acid/ethylene-responsive gene AtPDF1.2 in AtERF014-RNAi plants was intensified but expression of AtPDF1.2 in AtERF014-OE plants and of AtPR1 and AtPR5 in AtERF014-RNAi plants was weakened. After Bc infection, expression of AtPR1 and AtPR5 in AtERF014-OE plants was attenuated but expression of AtPR1, AtPR5 and AtPDF1.2 in AtERF014-RNAi plants was strengthened. Pathogen- and flg22-induced ROS burst, expression of PTI genes and SA-induced defense were partially suppressed in AtERF014-RNAi plants, whereas pathogen-induced ROS and flg22-induced immune response were strengthened in AtER014-OE plants. Altered expression of AtERR014 affected expression of pectin biosynthetic genes and pectin content in AtERF014-RNAi plants was decreased. These data demonstrate that AtERF014 acts as a dual regulator that differentially modulates immunity against Pst and Bc in Arabidopsis.

  15. PV Derived Data for Predicting Performance; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Marion, Bill

    2015-09-14

    A method is described for providing solar irradiance data for modeling PV performance by using measured PV performance data and back-solving for the unknown direct normal irradiance (DNI) and diffuse horizontal irradiance (DHI), which can then be used to model the performance of PV systems of any size, PV array tilt, or PV array azimuth orientation. Ideally situated for using the performance data from PV modules with micro-inverters, the PV module operating current is used to determine the global tilted irradiance (GTI), and a separation model is then used to determine the DNI and DHI from the GTI.

  16. Effect of wind speed on performance of a solar-pv array

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thousands of solar photovoltaic (PV) arrays have been installed over the past few years, but the effect of wind speed on the predicted performance of PV arrays is not usually considered by installers. An increase in wind speed will cool the PV array, and the electrical power of the PV modules will ...

  17. Cholesterol modulates interaction between an amphipathic class A peptide, Ac-18A-NH2, and phosphatidylcholine bilayers.

    PubMed

    Egashira, Masashi; Gorbenko, Galyna; Tanaka, Masafumi; Saito, Hiroyuki; Molotkovsky, Julian; Nakano, Minoru; Handa, Tetsurou

    2002-03-26

    Cholesterol (Chol) in phosphatidylcholine large unilamellar vesicles (PC LUV) modulated interaction of the bilayers with a class A amphipathic peptide, Ac-18A-NH2: Chol increased the peptide binding capacity and reduced the affinity together with the peptide-induced leakage of calcein from LUV. Similar effects of Chol have been observed on the interaction of LUV with apoA-I [Saito, H., Miyako, Y., Handa, T., and Miyajima, K. (1997) J. Lipid Res. 38, 287-294]. Circular dichroism (CD) spectra of the peptide indicated a similar helical structure formation in LUV with and without Chol. The fluorescence spectral shift, quantum yield, anisotropy, and acrylamide-quenching of the peptide Trp indicated that in PC:Chol (3:2) LUV, Ac-18A-NH2 was located in a more polar membrane environment with increased motional freedom and greater accessibility to the aqueous medium. Fluorescence energy transfer from the Trp indole ring to acceptors situated at different depths in the bilayers revealed that the amphipathic peptide penetrated the hydrophobic interior of PC bilayers, while the peptide was located at the polar zwitterionic surface in PC:Chol LUV. The inclusion of Chol causes the headgroup separation of PC at the surface of LUV and increases the binding maximum of the wedge-shaped amphipathic peptide without disrupting the membrane structure. In addition, the rigidifying effect of Chol on PC acyl chains prevents the penetration of the peptide into the bilayer interior. These findings imply that Chol in membranes affects the binding and motional freedom of exchangeable plasma apolipoproteins containing class A amphipathic sequences, e.g., apoA-I and apoCs.

  18. Space Station Freedom photovoltaic power module design status

    NASA Technical Reports Server (NTRS)

    Jimenez, Amador P.; Hoberecht, Mark A.

    1989-01-01

    Electric power generation for Space Station Freedom will be provided by four photovoltaic (PV) power modules using silicon solar cells during Phase 1 operation. Each PV power module requires two solar arrays with 32,800 solar cells generating 18.75 kW of dc power for a total of 75 kW. A portion of this power will be stored in nickel-hydrogen batteries for use during eclipse, and the balance will be processed and converted to 20 kHz ac power for distribution to end users through the power management and distribution system. The design incorporates an optimized thermal control system, pointing and tracking provision with the application of gimbals, and the use of orbital replacement units (ORU's) to achieve modularization. Design status of the PV power module, as derived from major trade studies, is discussed at hardware levels ranging from component to system. Details of the design are presented where appropriate.

  19. Space Station Freedom photovoltaic power module design status

    NASA Technical Reports Server (NTRS)

    Jimenez, Amador P.; Hoberecht, Mark A.

    1989-01-01

    Electric power generation for the Space Station Freedom will be provided by four photovoltaic (PV) power modules using silicon solar cells during phase I operation. Each PV power module requires two solar arrays with 32,800 solar cells generating 18.75 kW of dc power for a total of 75 kW. A portion of this power will be stored in nickel-hydrogen batteries for use during eclipse, and the balance will be processed and converted to 20 kHz ac power for distribution to end users through the power management and distribution system. The design incorporates an optimized thermal control system, pointing and tracking provision with the application of gimbals, and the use of orbital replacement units to achieve modularization. The design status of the PV power module, as derived from major trade studies, is discussed at hardware levels ranging from component to system. Details of the design are presented where appropriate.

  20. Energy 101: Solar PV

    ScienceCinema

    None

    2016-07-12

    Solar photovoltaic (PV) systems can generate clean, cost-effective power anywhere the sun shines. This video shows how a PV panel converts the energy of the sun into renewable electricity to power homes and businesses.

  1. Energy 101: Solar PV

    SciTech Connect

    2011-01-01

    Solar photovoltaic (PV) systems can generate clean, cost-effective power anywhere the sun shines. This video shows how a PV panel converts the energy of the sun into renewable electricity to power homes and businesses.

  2. Technology support for high-throughput processing of thin-film CdTe PV modules: Annual technical report, Phase 1, 1 April 1998--31 March 1999

    SciTech Connect

    Rose, D.H.; Powell, R.C.; Grecu, D.; Jayamaha, U.; Hanak, J.J.; Bohland, J.; Smigielski, K.; Dorer, G.L.

    1999-10-25

    This report describes work performed by First Solar, L.L.C., during Phase 1 of this 3-year subcontract. The research effort of this subcontract is divided into four areas: (1) process and equipment development, (2) efficiency improvement, (3) characterization and analysis, and (4) environmental, health, and safety. As part of the process development effort, the output of the pilot-production facility was increased. More than 6,200 8-ft{sup 2} CdS/CdTe plates were produced during Phase 1--more than double the total number produced prior to Phase 1. This increase in pilot-production rate was accomplished without a loss in the PV conversion efficiency: the average total-area AM1.5 efficiency of sub-modules produced during the reporting period was 6.4%. Several measurement techniques, such as large-area measurement of CdS thickness, were developed to aid process improvement, and the vapor-transport deposition method was refined. CdTe thickness uniformity and reproducibility were improved. From a population of more than 1,100 plates, the mean standard deviation within a plate was 7.3% and the standard deviation of individual-plate averages was 6.8%. As part of the efficiency-improvement task, research was done on devices with thin-CdS and buffer layers. A cell with 13.9% efficiency was produced on a high-quality substrate, and higher than 12% efficiency was achieved with a cell with no CdS layer. A number of experiments were performed as part of the characterization and analysis task. The temperature dependence of CdTe modules was investigated; the power output was found to be relatively insensitive (<5%) to temperature in the 25 to 50 C range. As part of the characterization and analysis task, considerable effort was also given to reliability verification and improvement. The most carefully monitored array, located at the NREL, was found to have unchanged power output within the margin of error of measurement (5%) after 5 years in the field. The first round of National

  3. Photoconductivity in AC-driven modulated two-dimensional electron gas in a perpendicular magnetic field.

    PubMed

    Torres, Manuel; Kunold, Alejandro

    2006-04-26

    In this work we study the microwave photoconductivity of a two-dimensional electron system (2DES) in the presence of a magnetic field and a two-dimensional modulation (2D). The model includes the microwave and Landau contributions in a non-perturbative exact way; the periodic potential is treated perturbatively. The Landau-Floquet states provide a convenient base with respect to which the lattice potential becomes time dependent, inducing transitions between the Landau-Floquet levels. Based on this formalism, we provide a Kubo-like formula that takes into account the oscillatory Floquet structure of the problem. The total longitudinal conductivity and resistivity exhibit strong oscillations, determined by ϵ = ω/ω(c), with ω the radiation frequency and ω(c) the cyclotron frequency. The oscillations follow a pattern with minima centred at [Formula: see text], and maxima centred at [Formula: see text], where j = 1,2,3..., δ∼1/5 is a constant shift and l is the dominant multipole contribution. Negative resistance states (NRSs) develop as the electron mobility and the intensity of the microwave power are increased. These NRSs appear in a narrow window region of values of the lattice parameter (a), around a∼l(B), where l(B) is the magnetic length. It is proposed that these phenomena may be observed in artificially fabricated arrays of periodic scatterers at the interface of ultraclean GaAs /Al(x)Ga(1-x)As heterostructures.

  4. Commercialization of PV-powered pumping systems for use in utility PV service programs. Final report

    SciTech Connect

    1997-03-01

    The project described in this report was a commercialization effort focused on cost-effective remote water pumping systems for use in utility-based photovoltaic (PV) service programs. The project combined a commercialization strategy tailored specifically for electric utilities with the development of a PV-powered pumping system that operates conventional ac pumps rather than relying on the more expensive and less reliable PV pumps on the market. By combining these two attributes, a project goal was established of creating sustained utility purchases of 250 PV-powered water pumping systems per year. The results of each of these tasks are presented in two parts contained in this Final Summary Report. The first part summarizes the results of the Photovoltaic Services Network (PSN) as a new business venture, while the second part summarizes the results of the Golden Photon system installations. Specifically, results and photographs from each of the system installations are presented in this latter part.

  5. Fire resistant PV shingle assembly

    SciTech Connect

    Lenox, Carl J.

    2012-10-02

    A fire resistant PV shingle assembly includes a PV assembly, including PV body, a fire shield and a connection member connecting the fire shield below the PV body, and a support and inter-engagement assembly. The support and inter-engagement assembly is mounted to the PV assembly and comprises a vertical support element, supporting the PV assembly above a support surface, an upper interlock element, positioned towards the upper PV edge, and a lower interlock element, positioned towards the lower PV edge. The upper interlock element of one PV shingle assembly is inter-engageable with the lower interlock element of an adjacent PV shingle assembly. In some embodiments the PV shingle assembly may comprise a ventilation path below the PV body. The PV body may be slidably mounted to the connection member to facilitate removal of the PV body.

  6. Development of a fully-integrated PV system for residential applications: Phase I annual technical report: February 27, 1998 -- August 31, 1999

    SciTech Connect

    West, R.; Mackamul, K.; Duran, G.

    2000-03-06

    This report describes Utility Power Group's (UPG's) technical progress for Phase 1 of a two-phase effort to focus on the design, assembly, and testing of a fully-integrated residential PV power system, including storage. In the PV Array Task, UPG significantly improved the conventional means and methods required to structurally interface PV modules to the roofs of single-family residential houses and to electrically interconnect these PV modules to a power conversion unit. UPG focused on the design and test of a PV array based on the highly efficient use of materials and labor. Design criteria included cost, structural integrity, electrical safety, reliability, conformance with applicable standards and building and seismic codes, and adaptability to a wide range of roof materials for both existing and retrofit roof applications. In the Power Unit Task, UPG designed and tested a high-efficiency, low-cost, high-reliability prototype power conversion unit that included all materials, components, equipment, and software required to perform all DC-AC/AC-DC power collection, conversion, and control functions between the output of the PV array and the interconnection to the electrical grid service of single-family residences. In the Energy Storage Unit Task, UPG designed and tested a low-cost, modular, self-contained, low-maintenance, all-weather, battery-based Energy Storage Unit designed to interface with the Power Unit to provide back-up electricity to supply critical household loads in the event of utility-grid failure. The Energy Storage Unit includes batteries and all structural, mechanical, and electrical equipment required to provide a source of stored DC energy for input of the Power Unit. UPG designed the storage unit as a ''plug and play'' option, where multiple units can be easily paralleled for additional energy storage capacity.

  7. Trajectory-Oriented and Fault-Tolerant-Based Intelligent Process Control for Flexible CIGS PV Module Manufacturing; Final Technical Report, 13 May 2002--30 May 2005

    SciTech Connect

    Simpson, L.; Britt, J.; Birkmire, R.; Vincent, T.

    2005-10-01

    ITN Energy Systems, Inc., and Global Solar Energy, Inc., assisted by NREL's PV Manufacturing R&D program, have continued to advance CIGS production technology by developing trajectory-oriented predictive/control models, fault-tolerance control, control platform development, in-situ sensors, and process improvements. Modeling activities included developing physics-based and empirical models for CIGS and sputter-deposition processing, implementing model-based control, and applying predictive models to the construction of new evaporation sources and for control. Model-based control is enabled by implementing reduced or empirical models into a control platform. Reliability improvement activities include implementing preventive maintenance schedules; detecting failed sensors/equipment and reconfiguring to tinue processing; and systematic development of fault prevention and reconfiguration strategies for the full range of CIGS PV production deposition processes. In-situ sensor development activities have resulted in improved control and indicated the potential for enhanced process status monitoring and control of the deposition processes. Substantial process improvements have been made, including significant improvement in CIGS uniformity, thickness control, efficiency, yield, and throughput. In large measure, these gains have been driven by process optimization, which in turn have been enabled by control and reliability improvements due to this PV Manufacturing R&D program.

  8. Fire hazard and other safety concerns of PV systems

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.

    2011-09-01

    Photovoltaic modules are usually considered safe and reliable. But in case of grid-connected PV systems that are becoming very popular, the issue of fire safety of PV modules is becoming increasingly important due to the employed high voltages of 600 V to 1000 V. The two main factors i.e. open circuiting of the bypass diode and ground fault that are responsible for the fire in the PV systems have been discussed in detail along with numerous real life examples. Recommendations are provided for preventing the fire hazards such as having at least class C fire rated PV modules, proper bypass and blocking diodes and interestingly, having an ungrounded PV system.

  9. PV_LIB Toolbox

    SciTech Connect

    2012-09-11

    While an organized source of reference information on PV performance modeling is certainly valuable, there is nothing to match the availability of actual examples of modeling algorithms being used in practice. To meet this need, Sandia has developed a PV performance modeling toolbox (PV_LIB) for Matlab. It contains a set of well-documented, open source functions and example scripts showing the functions being used in practical examples. This toolbox is meant to help make the multi-step process of modeling a PV system more transparent and provide the means for model users to validate and understand the models they use and or develop. It is fully integrated into Matlab’s help and documentation utilities. The PV_LIB Toolbox provides more than 30 functions that are sorted into four categories

  10. PV performance modeling workshop summary report.

    SciTech Connect

    Stein, Joshua S.; Tasca, Coryne Adelle; Cameron, Christopher P.

    2011-05-01

    During the development of a solar photovoltaic (PV) energy project, predicting expected energy production from a system is a key part of understanding system value. System energy production is a function of the system design and location, the mounting configuration, the power conversion system, and the module technology, as well as the solar resource. Even if all other variables are held constant, annual energy yield (kWh/kWp) will vary among module technologies because of differences in response to low-light levels and temperature. A number of PV system performance models have been developed and are in use, but little has been published on validation of these models or the accuracy and uncertainty of their output. With support from the U.S. Department of Energy's Solar Energy Technologies Program, Sandia National Laboratories organized a PV Performance Modeling Workshop in Albuquerque, New Mexico, September 22-23, 2010. The workshop was intended to address the current state of PV system models, develop a path forward for establishing best practices on PV system performance modeling, and set the stage for standardization of testing and validation procedures for models and input parameters. This report summarizes discussions and presentations from the workshop, as well as examines opportunities for collaborative efforts to develop objective comparisons between models and across sites and applications.

  11. Technology support for initiation of high-throughput processing of thin-film CdTe PV modules. Phase 3 final technical report, 14 March 1997--1 April 1998

    SciTech Connect

    Powell, R.C.; Dorer, G.L.; Jayamaha, U.; Hanak, J.J.

    1998-09-01

    Thin-film PV devices based on cadmium telluride have been identified as one of the candidates for high-performance, low-cost source of renewable electrical energy. Roadblocks to their becoming a part of the booming PV market growth have been a low rate of production and high manufacturing cost caused by several rate-limiting process steps. Solar Cells Inc. has focused on the development of manufacturing processes that will lead to high volume and low-cost manufacturing of solar cells and on increasing the performance of the present product. The process research in Phase 3 was concentrated on further refinement of a newly developed vapor transport deposition (VTD) process and its implementation into the manufacturing line. This development included subsystems for glass substrate transport, continuous feed of source materials, generation of source vapors, and uniform deposition of the semiconductor layers. As a result of this R and D effort, the VTD process has now achieved a status in which linear coating speeds in excess of 8 ft/min have been achieved for the semiconductor, equal to about two modules per minute, or 144 kW per 24 hour day. The process has been implemented in a production line, which is capable of round-the-clock continuous production of coated substrates 120 cm x 60 cm in size at a rate of 1 module every four minutes, equal to 18 kW/day. Currently the system cycle time is limited by the rate of glass introduction into the system and glass heating, but not by the rate of the semiconductor deposition. A new SCI record efficiency of 14.1% has been achieved for the cells.

  12. Plug and Play Components for Building Integrated PV Systems, Phase II Final Report, 20 February 2003 - 31 May 2007

    SciTech Connect

    Rowell, D.

    2008-04-01

    Progress by Schott Solar, Inc. under NREL's PV Manufacturing R&D Project. Details progress on meter-interconnect device; free-standing mounting system; dark I-V curves to unearth problems with PV module strings; new 34-V version of ASE-300 PV module; and updated source-circuit protectors.

  13. Dynamic Model Validation of PV Inverters Under Short-Circuit Conditions: Preprint

    SciTech Connect

    Muljadi, E.; Singh, M.; Bravo, R.; Gevorgian, V.

    2013-03-01

    Photovoltaic (PV) modules have dramatically decreased in price in the past few years, spurring the expansion of photovoltaic deployment. Residential and commercial rooftop installations are connected to the distribution network; large-scale installation PV power plants (PVPs) have benefited from tax incentives and the low cost of PV modules. As the level penetration of PV generation increases, the impact on power system reliability will also be greater. Utility power system planners must consider the role of PV generation in power systems more realistically by representing PV generation in dynamic stability analyses. Dynamic models of PV inverters have been developed in the positive sequence representation. NREL has developed a PV inverter dynamic model in PSCAD/EMTDC. This paper validates the dynamic model with an actual hardware bench test conducted by Southern California Edison's Distributed Energy Resources laboratory. All the fault combinations -- symmetrical and unsymmetrical -- were performed in the laboratory. We compare the simulation results with the bench test results.

  14. GridPV Toolbox

    SciTech Connect

    Broderick, Robert; Quiroz, Jimmy; Grijalva, Santiago; Reno, Matthew; Coogan, Kyle

    2014-07-15

    Matlab Toolbox for simulating the impact of solar energy on the distribution grid. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving GridPV Toolbox information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions.

  15. Differential modulation of plant immune responses by diverse members of the Pseudomonas savastanoi pv. savastanoi HopAF type III effector family.

    PubMed

    Castañeda-Ojeda, M Pilar; López-Solanilla, Emilia; Ramos, Cayo

    2016-04-26

    The Pseudomonas savastanoi pv. savastanoi NCPPB 3335 type III secretion system (T3SS) effector repertoire includes 33 candidates, seven of which translocate into host cells and interfere with plant defences. The present study was performed to investigate the co-existence of both plasmid- and chromosomal-encoded members of the HopAF effector family, HopAF1-1 and HopAF1-2, respectively, in the genome of NCPPB 3335. Here, we show that the HopAF1 paralogues are widely distributed in the Pseudomonas syringae complex, where HopAF1-1 is most similar to the homologues encoded by other P. syringae pathovars infecting woody hosts that belong to phylogroups 1 and 3. We show that the expression of both HopAF1-1 and HopAF-2 is transcriptionally dependent on HrpL and demonstrate their delivery into Nicotiana tabacum leaves. Although the heterologous delivery of either HopAF1-1 or HopAF1-2 significantly suppressed the production of defence-associated reactive oxygen species levels, only HopAF1-2 reduced the levels of callose deposition. Moreover, the expression of HopAF1-2 by functionally effectorless P. syringae pv. tomato DC3000D28E completely inhibited the hypersensitive response in tobacco and significantly increased the competitiveness of the strain in Nicotiana benthamiana. Despite their functional differences, subcellular localization studies reveal that green fluorescent protein (GFP) fusions to either HopAF1-1 or HopAF1-2 are targeted to the plasma membrane when they are expressed in plant cells, a process that is completely dependent on the integrity of their N-myristoylation motif. Our results further support the notion that highly similar T3SS effectors might differentially interact with diverse plant targets, even when they co-localize in the same cell compartment.

  16. ACS: ALMA Common Software

    NASA Astrophysics Data System (ADS)

    Chiozzi, Gianluca; Šekoranja, Matej

    2013-02-01

    ALMA Common Software (ACS) provides a software infrastructure common to all ALMA partners and consists of a documented collection of common patterns and components which implement those patterns. The heart of ACS is based on a distributed Component-Container model, with ACS Components implemented as CORBA objects in any of the supported programming languages. ACS provides common CORBA-based services such as logging, error and alarm management, configuration database and lifecycle management. Although designed for ALMA, ACS can and is being used in other control systems and distributed software projects, since it implements proven design patterns using state of the art, reliable technology. It also allows, through the use of well-known standard constructs and components, that other team members whom are not authors of ACS easily understand the architecture of software modules, making maintenance affordable even on a very large project.

  17. Statistical overview of findings by IR-inspections of PV-plants

    NASA Astrophysics Data System (ADS)

    Buerhop, Claudia; Pickel, Tobias; Scheuerpflug, Hans; Camus, Christian; Hauch, Jens; Brabec, Christoph J.

    2016-09-01

    First statistical evaluation of IR-inspections of PV-plants reveals that 86% of the installed PV-plants show IR-abnormalities. More than 120 PV-plants with more than 160,000 PV-modules were inspected and evaluated statistically. Main IR-abnormalities or failures in modules and string installations are analyzed, respectively. The average failure rate for PV-modules is about 8% and for module strings approximately 4%. The differentiation between the installation locations reveals that small residential installation show relatively more defective modules than large field installations. - Therefore, IR-imaging is a valuable method to give fast and reliable information about the actual quality and failure rate in inspected PV-installations.

  18. Grid integrated distributed PV (GridPV).

    SciTech Connect

    Reno, Matthew J.; Coogan, Kyle

    2013-08-01

    This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions. Each function in the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.

  19. Evaluation of Encapsulant Materials for PV Applications

    SciTech Connect

    Kempe, M.

    2010-01-01

    Encapsulant materials used in PV modules serve multiple purposes. They physically hold components in place, provide electrical insulation, optically couple superstrate materials (e.g., glass) to PV cells, protect components from mechanical stress by mechanically de-coupling components via strain relief, and protect materials from corrosion. To do this, encapsulants must adhere well to all surfaces, remain compliant, and transmit light after exposure to temperature, humidity, and UV radiation histories. Encapsulant materials by themselves do not completely prevent water vapour ingress [1-3], but if they are well adhered, they will prevent the accumulation of liquid water providing protection against corrosion as well as electrical shock. Here, a brief review of some of the polymeric materials under consideration for PV applications is provided, with an explanation of some of their advantages and disadvantages.

  20. Bracket for photovoltaic modules

    SciTech Connect

    Ciasulli, John; Jones, Jason

    2014-06-24

    Brackets for photovoltaic ("PV") modules are described. In one embodiment, a saddle bracket has a mounting surface to support one or more PV modules over a tube, a gusset coupled to the mounting surface, and a mounting feature coupled to the gusset to couple to the tube. The gusset can have a first leg and a second leg extending at an angle relative to the mounting surface. Saddle brackets can be coupled to a torque tube at predetermined locations. PV modules can be coupled to the saddle brackets. The mounting feature can be coupled to the first gusset and configured to stand the one or more PV modules off the tube.

  1. PV system field experience and reliability

    NASA Astrophysics Data System (ADS)

    Durand, Steven; Rosenthal, Andrew; Thomas, Mike

    1997-02-01

    Hybrid power systems consisting of battery inverters coupled with diesel, propane, or gasoline engine-driven electrical generators, and photovoltaic arrays are being used in many remote locations. The potential cost advantages of hybrid systems over simple engine-driven generator systems are causing hybrid systems to be considered for numerous applications including single-family residential, communications, and village power. This paper discusses the various design constraints of such systems and presents one technique for reducing hybrid system losses. The Southwest Technology Development Institute under contract to the National Renewable Energy Laboratory and Sandia National Laboratories has been installing data acquisition systems (DAS) on a number of small and large hybrid PV systems. These systems range from small residential systems (1 kW PV - 7 kW generator), to medium sized systems (10 kW PV - 20 kW generator), to larger systems (100 kW PV - 200 kW generator). Even larger systems are being installed with hundreds of kilowatts of PV modules, multiple wind machines, and larger diesel generators.

  2. Photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Lenox, Carl J. S. [Oakland, CA; Culligan, Matthew [Berkeley, CA; Danning, Matt [Oakland, CA

    2012-07-17

    A photovoltaic (PV) module including a PV device and a frame. The PV device has a PV laminate defining a perimeter and a major plane. The frame is assembled to and encases the laminate perimeter, and includes leading, trailing, and side frame members, and an arm that forms a support face opposite the laminate. The support face is adapted for placement against a horizontal installation surface, to support and orient the laminate in a non-parallel or tilted arrangement. Upon final assembly, the laminate and the frame combine to define a unitary structure. The frame can orient the laminate at an angle in the range of 3.degree.-7.degree. from horizontal, and can be entirely formed of a polymeric material. Optionally, the arm incorporates integral feature(s) that facilitate interconnection with corresponding features of a second, identically formed PV module.

  3. Photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Lenox, Carl J. S.; Culligan, Matthew; Danning, Matt

    2013-08-27

    A photovoltaic (PV) module including a PV device and a frame, The PV device has a PV laminate defining a perimeter and a major plane. The frame is assembled to and encases the laminate perimeter, and includes leading, trailing, and side frame members, and an arm that forms a support face opposite the laminate. The support face is adapted for placement against a horizontal installation surface, to support and orient the laminate in a non-parallel or tilted arrangement. Upon final assembly, the laminate and the frame combine to define a unitary structure. The frame can orient the laminate at an angle in the range of 3.degree.-7.degree. from horizontal, and can be entirely formed of a polymeric material. Optionally, the arm incorporates integral feature(s) that facilitate interconnection with corresponding features of a second, identically formed PV module.

  4. Open PV Project: Unlocking PV Installation Data (Brochure)

    SciTech Connect

    Not Available

    2012-04-01

    This brochure summarizes the Open PV Project, a collaborative effort of government, industry, and the public to compile a comprehensive database of PV installations in the United States. The brochure outlines the purpose and history of the project as well as the main capabilities and benefits of the online Open PV tool. The brochure also introduces how features of the tool are used, and it describes the sources and characteristics of Open PV's data and data collection processes.

  5. Photovoltaic Module Reliability Workshop 2013: February 26-27, 2013

    SciTech Connect

    Kurtz, S.

    2013-10-01

    NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

  6. Photovoltaic Module Reliability Workshop 2012: February 28 - March 1, 2012

    SciTech Connect

    Kurtz, S.

    2013-11-01

    NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

  7. Photovoltaic Module Reliability Workshop 2014: February 25-26, 2014

    SciTech Connect

    Kurtz, S.

    2014-02-01

    NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

  8. Photovoltaic Module Reliability Workshop 2011: February 16-17, 2011

    SciTech Connect

    Kurtz, S.

    2013-11-01

    NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

  9. Photovoltaic Module Reliability Workshop 2010: February 18-19, 2010

    SciTech Connect

    Kurtz, J.

    2013-11-01

    NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

  10. Performance and Degradation Analysis of Operating PV Systems

    NASA Astrophysics Data System (ADS)

    Da Silva Freire, Felipe

    The environmental concerns together with the decrease in technology cost lead the solar market to growth rapidly along the last decade. The photovoltaic (PV) systems are one of the solar energy alternatives and the silicon solar cells are currently the most widespread technology. Photovoltaic (PV) modules are considered the most reliable component of a photovoltaic system. The reliability and lifetime depends on the modules energy conversion performance and degradation modes. The analysis of monitoring data give insights about the PV system performance along its service time. The comparison between this data and mathematical models configure a way to predict the futures and new PV installations performance. The goal of this study is to understand the PV systems performance and degradation along its lifetime. A mathematical model was employed to predict the power output of a real, relatively new operating PV system with respect to environmental parameters temperature, irradiance and cloud coverage. The model used is based on one diode ideality factor and takes into account the parasitic series resistance. The results have been compared with the actual PV output data collected for the year 2014 and show good correlation. As the model predicts the system power output assuming the system in new conditions, the deviation in performance of the real data in comparison to the modeling results need to be further investigated for systems in service for longer time. For this propose, the study presents a condensed review of various causes of degradation in silicon PV modules and techniques to observe and investigate these degradation mechanisms. Major effects on output performance exhibit increase in observed ideality factor n2 and recombination current J02 primarily caused by decrease in minority carrier lifetime, shunts and increase in series resistance. The study further, investigates the governing degradation modes on a ten years old PV crystalline silicon module

  11. Evaluating the causes of photovoltaics cost reduction: Why is PV different?

    SciTech Connect

    Trancik, Jessika; McNerney, James; Kavlak, Goksin

    2016-12-29

    The goals of this project were to quantify sources of cost reduction in photovoltaics (PV), improve theories of technological evolution, develop new analytical methods, and formu- late guidelines for continued cost reduction in photovoltaics. A number of explanations have been suggested for why photovoltaics have come down in cost rapidly over time, including increased production rates, significant R&D expenditures, heavy patenting ac- tivity, decreasing material and input costs, scale economies, reduced plant construction costs, and higher conversion efficiencies. We classified these proposed causes into low- level factors and high-level drivers. Low-level factors include technical characteristics, such as module efficiency or wafer area, which are easily posed in terms of variables of a cost equation. High-level factors include scale economies, research and development (R&D), and learning-by-doing.

  12. Testing for PV Reliability (Presentation)

    SciTech Connect

    Kurtz, S.; Bansal, S.

    2014-09-01

    The DOE SUNSHOT workshop is seeking input from the community about PV reliability and how the DOE might address gaps in understanding. This presentation describes the types of testing that are needed for PV reliability and introduces a discussion to identify gaps in our understanding of PV reliability testing.

  13. Effects of module performance and long-term degradation on economics and energy payback: case study of two different photovoltaic technologies

    NASA Astrophysics Data System (ADS)

    Davis, Kristopher; Moaveni, H.

    2009-08-01

    Both the economic viability and energy payback time of photovoltaic (PV) systems are inextricably tied to both the electrical performance and degradation rate of PV modules. Different module technologies exhibit different properties in response to varying environmental conditions over time. The purpose of this study is to quantify the effects of those differences on the life-cycle economical cost and energy payback time of two fielded PV systems; one system comprised of polycrystalline silicon (c-Si) modules and one featuring hydrogenated amorphous silicon (a-Si) modules. The DC operating current, DC operating voltage, AC power, and conversion efficiency of each system have been monitored for a period of over four years, along with plane-of-array (POA) irradiance, module temperature, and ambient temperature. Electrical performance is evaluated in terms of final PV system yield (Yf), reference yield (Yr), and performance ratio (PR), which are derived from the primary international standard used to evaluate PV system performance, IEC 617241. Degradation rates were evaluated over the four year period using regression analysis. The empirically determined trends in long-term performance were then used to approximate the energy produced by both system types under the same environmental conditions; most importantly, the same levels of solar irradiation. Based on this modeled energy production and economic conditions specific to the state of Florida, comparisons have been carried out for life-cycle costs and energy payback time.

  14. Sub-Doppler spectra of infrared hyperfine transitions of nitric oxide using a pulse modulated quantum cascade laser: rapid passage, free induction decay, and the ac Stark effect.

    PubMed

    Duxbury, Geoffrey; Kelly, James F; Blake, Thomas A; Langford, Nigel

    2012-05-07

    Using a low power, rapid (nsec) pulse-modulated quantum cascade (QC) laser, collective coherent effects in the 5 μm spectrum of nitric oxide have been demonstrated by the observation of sub-Doppler hyperfine splitting and also Autler-Townes splitting of Doppler broadened lines. For nitrous oxide, experiments and model calculations have demonstrated that two main effects occur with pulse-modulated (chirped) quantum cascade lasers: free induction decay signals, and signals induced by rapid passage during the laser chirp. In the open shell molecule, NO, in which both Λ-doubling splitting and hyperfine structure occur, laser field-induced coupling between the hyperfine levels of the two Λ-doublet components can induce a large ac Stark effect. This may be observed as sub-Doppler structure, field-induced splittings, or Autler-Townes splitting of a Doppler broadened line. These represent an extension of the types of behaviour observed in the closed shell molecule nitrous oxide, using the same apparatus, when probed with an 8 μm QC laser.

  15. PV Manufacturing R&D Project -- Trends in the U.S. PV Industry

    SciTech Connect

    Brown, K. E.; Mitchell, R. L.; Bower, W. I.; King, R.

    2005-01-01

    To foster continued growth in the U.S. photovoltaic (PV) industry, the U.S. Department of Energy initiated the PV Manufacturing R&D (PVMR&D) Project--a partnership with U.S. PV industry participants to perform cost-shared manufacturing research and development. Throughout FY 2004, PVMR&D managed fourteen subcontracts across the industry. The impact of PVMR&D is quantified by reductions in direct module manufacturing costs, scale-up of existing PV production capacity, and accrual of cost savings to the public and industry. An analysis of public and industry investment shows that both recaptured funds by mid-1998 based on estimated manufacturing cost savings from PVMR&D participation. Since project inception, total PV manufacturing capacity has increased from 14 MW to 201 MW at the close of 2003, while direct manufacturing costs declined from $5.55/W to $2.49/W. These results demonstrate continued progress toward the overriding goals of the PVMR&D project.

  16. Quantifying PV power Output Variability

    SciTech Connect

    Hoff, Thomas E.; Perez, Richard

    2010-10-15

    This paper presents a novel approach to rigorously quantify power Output Variability from a fleet of photovoltaic (PV) systems, ranging from a single central station to a set of distributed PV systems. The approach demonstrates that the relative power Output Variability for a fleet of identical PV systems (same size, orientation, and spacing) can be quantified by identifying the number of PV systems and their Dispersion Factor. The Dispersion Factor is a new variable that captures the relationship between PV Fleet configuration, Cloud Transit Speed, and the Time Interval over which variability is evaluated. Results indicate that Relative Output Variability: (1) equals the inverse of the square root of the number of systems for fully dispersed PV systems; and (2) could be further minimized for optimally-spaced PV systems. (author)

  17. PV Hourly Simulation Tool

    SciTech Connect

    Dean, Jesse; Metzger, Ian

    2010-12-31

    This software requires inputs of simple general building characteristics and usage information to calculate the energy and cost benefits of solar PV. This tool conducts and complex hourly simulation of solar PV based primarily on the area available on the rooftop. It uses a simplified efficiency calculation method and real panel characteristics. It includes a detailed rate structure to account for time-of-use rates, on-peak and off-peak pricing, and multiple rate seasons. This tool includes the option for advanced system design inputs if they are known. This tool calculates energy savings, demand reduction, cost savings, incentives and building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.

  18. Rooftop PV system. Final technical progress report, Phase II

    SciTech Connect

    1995-08-01

    Under this four-year PV:BONUS Program, ECD and United Solar are developing and demonstrating two new lightweight flexible building integrated Photovoltaic (BIPV) modules specifically designed as exact replacements for conventional asphalt shingles and standing seam metal roofing. These modules can be economically and aesthetically integrated into new residential and commercial buildings, and address the even larger roofing replacement market. The modules are designed to be installed by roofing contractors without special training which minimizes the installation and balance of system costs. The modules will be fabricated from high-efficiency, multiple-junction a-Si alloy solar cells developed by ECD and United Solar. Under the Phase I Program, which ended in March 1994, we developed two different concept designs for rooftop PV modules: (1) the United Solar overlapping (asphalt shingle replacement) shingle-type modules and (2) the ECD metal roof-type modules. We also developed a plan for fabricating, testing and demonstrating these modules. Candidate demonstration sites for our rooftop PV modules were identified and preliminary engineering designs for these demonstrations were developed; a marketing study plan was also developed. The major objectives of the Phase II Program, which started in June 1994 was (1) to develop, test, and qualify these new rooftop modules; (2) to develop mechanical and electrical engineering specifications for the demonstration projects; and (3) to develop a marketing/commercialization plan.

  19. Plug and Play PV Systems for American Homes

    SciTech Connect

    Hoepfner, Christian

    2016-12-22

    The core objectives of the Plug & Play PV Systems Project were to develop a PV system that can be installed on a residential rooftop for less than $1.50/W in 2020, and in less than 10 hours (from point of purchase to commissioning). The Fraunhofer CSE team’s approach to this challenge involved a holistic approach to system design – hardware and software – that make Plug & Play PV systems: • Quick, easy, and safe to install • Easy to demonstrate as code compliant • Permitted, inspected, and interconnected via an electronic process Throughout the three years of work during this Department of Energy SunShot funded project, the team engaged in a substantive way with inspectional services departments and utilities, manufacturers, installers, and distributors. We received iterative feedback on the system design and on ideas for how such systems can be commercialized. This ultimately led us to conceiving of Plug & Play PV Systems as a framework, with a variety of components compatible with the Plug & Play PV approach, including string or microinverters, conventional modules or emerging lightweight modules. The framework enables a broad group of manufacturers to participate in taking Plug & Play PV Systems to market, and increases the market size for such systems. Key aspects of the development effort centered on the system hardware and associated engineering work, the development of a Plug & Play PV Server to enable the electronic permitting, inspection and interconnection process, understanding the details of code compliance and, on occasion, supporting applications for modifications to the code to allow lightweight modules, for example. We have published a number of papers on our testing and assessment of novel technologies (e.g., adhered lightweight modules) and on the electronic architecture.

  20. Photovoltaic module parameters acquisition model

    NASA Astrophysics Data System (ADS)

    Cibira, Gabriel; Koščová, Marcela

    2014-09-01

    This paper presents basic procedures for photovoltaic (PV) module parameters acquisition using MATLAB and Simulink modelling. In first step, MATLAB and Simulink theoretical model are set to calculate I-V and P-V characteristics for PV module based on equivalent electrical circuit. Then, limited I-V data string is obtained from examined PV module using standard measurement equipment at standard irradiation and temperature conditions and stated into MATLAB data matrix as a reference model. Next, the theoretical model is optimized to keep-up with the reference model and to learn its basic parameters relations, over sparse data matrix. Finally, PV module parameters are deliverable for acquisition at different realistic irradiation, temperature conditions as well as series resistance. Besides of output power characteristics and efficiency calculation for PV module or system, proposed model validates computing statistical deviation compared to reference model.

  1. PV water pumping: NEOS Corporation recent PV water pumping activities

    SciTech Connect

    Lane, C.

    1995-11-01

    NEOS Corporation has been very active in PV-powered water pumping, particularly with respect to electric utilities. Most of the recent activity has been through the Photovoltaic Services Network (PSN). The PSN is an independent, not-for-profit organization comprised of all types of electric utilities: rural electric coops, public power districts, investor-owned utilities, and power marketing agencies. The PSN`s mission is to work pro-actively to promote utility involvement in PV through education and training. PV information is distributed by the PSN in three primary forms: (1) consultation with PSN technical service representatives: (2) literature generated by the PSN; and (3) literature published by other organizations. The PSN can also provide assistance to members in developing PV customer service programs. The PSN`s product support activities include consolidation of information on existing packaged PV systems and facilitation of the development of new PV product packages that meet utility-defined specifications for cost performance, and reliability. The PSN`s initial product support efforts will be focused on commercially available packaged PV systems for a variety of off-grid applications. In parallel with this effort, if no products exist that meet the PSN`s functional specifications, the PSN will initiate the second phase of product development support process by encouraging the development of new packaged systems. Through these services and product support activities, the PSN anticipates engaging all segments for the PV industry, thus providing benefits to PV systems suppliers as well as local PV service contractors.This paper describes field testing of pv power systems for water pumping.

  2. Sub-Doppler Spectra of Infrared Hyperfine Transitions of Nitric Oxide Using a Pulse Modulated Quantum Cascade Laser: Rapid Passage, Free Induction Decay and the AC Stark Effect

    SciTech Connect

    Duxbury, Geoffrey; Kelly, James F.; Blake, Thomas A.; Langford, Nigel

    2012-05-07

    Using a low power, rapid (nsec) pulse-modulated quantum cascade (QC) laser, collective coherent effects in the 5 {micro}m spectrum of nitric oxide have been demonstrated by the observation of sub-Doppler hyperfine splitting and also Autler-Townes splitting of Doppler broadened lines. For nitrous oxide, experiments and model calculations have demonstrated that two main effects occur with ulsemodulated (chirped) quantum cascade lasers: free induction decay signals, and signals induced by rapid passage during the laser chirp. In the open shell molecule, NO, in which both {Lambda}-doubling splitting and hyperfine structure occur, laser field-induced coupling between the hyperfine levels of the two {Lambda}-doublet components can induce a large AC Stark effect. This may be observed as sub-Doppler structure, field-induced splittings, or Autler-Townes splitting of a Doppler broadened line. These represent an extension of the types of behaviour observed in the closed shell molecule nitrous oxide, using the same apparatus, when probed with an 8 {micro}m QC laser.

  3. An adaptive neuro fuzzy inference system controlled space cector pulse width modulation based HVDC light transmission system under AC fault conditions

    NASA Astrophysics Data System (ADS)

    Ajay Kumar, M.; Srikanth, N. V.

    2014-03-01

    In HVDC Light transmission systems, converter control is one of the major fields of present day research works. In this paper, fuzzy logic controller is utilized for controlling both the converters of the space vector pulse width modulation (SVPWM) based HVDC Light transmission systems. Due to its complexity in the rule base formation, an intelligent controller known as adaptive neuro fuzzy inference system (ANFIS) controller is also introduced in this paper. The proposed ANFIS controller changes the PI gains automatically for different operating conditions. A hybrid learning method which combines and exploits the best features of both the back propagation algorithm and least square estimation method is used to train the 5-layer ANFIS controller. The performance of the proposed ANFIS controller is compared and validated with the fuzzy logic controller and also with the fixed gain conventional PI controller. The simulations are carried out in the MATLAB/SIMULINK environment. The results reveal that the proposed ANFIS controller is reducing power fluctuations at both the converters. It also improves the dynamic performance of the test power system effectively when tested for various ac fault conditions.

  4. ac bidirectional motor controller

    NASA Technical Reports Server (NTRS)

    Schreiner, K.

    1988-01-01

    Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ac bus being designed for the Space Station. A zero-voltage-switching pulse-density-modulation technique is used in the converter to shape the low-frequency output waveform.

  5. Interband cascade (IC) photovoltaic (PV) architecture for PV devices

    DOEpatents

    Yang, Rui Q.; Tian, Zhaobing; Mishima, Tetsuya D.; Santos, Michael B.; Johnson, Matthew B.; Klem, John F.

    2015-10-20

    A photovoltaic (PV) device, comprising a PV interband cascade (IC) stage, wherein the IC PV stage comprises an absorption region with a band gap, the absorption region configured to absorb photons, an intraband transport region configured to act as a hole barrier, and an interband tunneling region configured to act as an electron barrier. An IC PV architecture for a photovoltaic device, the IC PV architecture comprising an absorption region, an intraband transport region coupled to the absorption region, and an interband tunneling region coupled to the intraband transport region and to the adjacent absorption region, wherein the absorption region, the intraband transport region, and the interband tunneling region are positioned such that electrons will flow from the absorption region to the intraband transport region to the interband tunneling region.

  6. Moving to a Higher Level for PV Reliability through Comprehensive Standards Based on Solid Science (Presentation)

    SciTech Connect

    Kurtz, S.

    2014-11-01

    PV reliability is a challenging topic because of the desired long life of PV modules, the diversity of use environments and the pressure on companies to rapidly reduce their costs. This presentation describes the challenges, examples of failure mechanisms that we know or don't know how to test for, and how a scientific approach is being used to establish international standards.

  7. The Present, Mid-Term, and Long-Term Supply Curves for Tellurium; and Updates in the Results from NREL's CdTe PV Module Manufacturing Cost Model (Presentation)

    SciTech Connect

    Woodhouse, M.; Goodrich, A.; Redlinger, M.; Lokanc, M.; Eggert, R.

    2013-09-01

    For those PV technologies that rely upon Te, In, and Ga, first-order observations and calculations hint that there may be resource constraints that could inhibit their successful deployment at a SunShot level. These are only first-order approximations, however, and the possibility for an expansion in global Te, In, and Ga supplies needs to be considered in the event that there are upward revisions in their demand and prices.In this study, we examine the current, mid-term, and long-term prospects of Tellurium (Te) for use in PV. We find that the current global supply base of Te would support <10 GW of annual traditional CdTe PV manufacturing production. But as for the possibility that the supply base for Te might be expanded, after compiling several preliminary cumulative availability curves we find that there may be significant upside potential in the supply base for this element - principally vis a vis increasing demand and higher prices. Primarily by reducing the Tellurium intensity in manufacturing and by increasing the recovery efficiency of Te in Cu refining processes, we calculate that it may prove affordable to PV manufacturers to expand the supply base for Te such that 100 GW, or greater, of annual CdTe PV production is possible in the 2030 - 2050 timeframe.

  8. 3-Port Single-Stage PV & Battery Converter Improves Efficiency and Cost in Combined PV/Battery Systems

    SciTech Connect

    Bundschuh, Paul

    2013-03-23

    Due to impressive cost reductions in recent years, photovoltaic (PV) generation is now able to produce electricity at highly competitive prices, but PV’s inherent intermittency reduces the potential value of this energy. The integration of battery storage with PV will be transformational by increasing the value of solar. Utility scale systems will benefit by firming intermittency including PV ramp smoothing, grid support and load shifting, allowing PV to compete directly with conventional generation. For distributed grid-tied PV adding storage will reduce peak demand utility charges, as well as providing backup power during power grid failures. The largest long term impact of combined PV and battery systems may be for delivering reliable off-grid power to the billions of individuals globally without access to conventional power grids, or for billions more that suffer from daily power outages. PV module costs no longer dominate installed PV system costs. Balance-of-System (BOS) costs including the PV inverter and installation now contribute the majority of installed system costs. Battery costs are also dropping faster than installation and battery power converter systems. In each of these separate systems power converters have become a bottleneck for efficiency, cost and reliability. These bottlenecks are compounded in hybrid power conversion systems that combine separate PV and battery converters. Hybrid power conversion systems have required multiple power converters hardware units and multiple power conversion steps adding to efficiency losses, product and installation costs, and reliability issues. Ideal Power Converters has developed and patented a completely new theory of operation for electronic power converters using its indirect EnergyPacket Switching™ topology. It has established successful power converter products for both PV and battery systems, and its 3-Port Hybrid Converter is the first product to exploit the topology’s capability for the

  9. Moving Toward Quantifying Reliability - The Next Step in a Rapidly Maturing PV Industry: Preprint

    SciTech Connect

    Kurtz, Sarah; Sample, Tony; Wohlgemuth, John; Zhou, Wei; Bosco, Nick; Althaus, Joerg; Phillips, Nancy; Deceglie, Michael; Flueckiger, Chris; Hacke, Peter; Miller, David; Kempe, Michael; Yamamichi, Masaaki; Kondo, Michio

    2015-12-07

    Some may say that PV modules are moving toward being a simple commodity, but most major PV customers ask: 'How can I minimize chances of a module recall?' Or, 'How can I quantify the added value of a 'premium' module?' Or, 'How can I assess the value of an old PV system that I'm thinking of purchasing?' These are all questions that PVQAT (the International PV Quality Assurance Task Force) and partner organizations are working to answer. Defining standard methods for ensuring minimal acceptable quality of PV modules, differentiating modules that provide added value in the toughest of environments, and creating a process (e.g. through IECRE [1]) that can follow a PV system from design through installation and operation are tough tasks, but having standard approaches for these will increase confidence, reduce costs, and be a critical foundation of a mature PV industry. This paper summarizes current needs for new tests, some challenges for defining those tests, and some of the key efforts toward development of international standards, emphasizing that meaningful quantification of reliability (as in defining a service life prediction) must be done in the context of a specific product with design parameters defined through a quality management system.

  10. Moving Toward Quantifying Reliability - The Next Step in a Rapidly Maturing PV Industry

    SciTech Connect

    Kurtz, Sarah; Sample, Tony; Wohlgemuth, John; Zhou, Wei; Bosco, Nick; Althaus, Joerg; Phillips, Nancy; Deceglie, Michael; Flueckiger, Chris; Hacke, Peter; Miller, David; Kempe, Michael; Yamamichi, Masaaki; Kondo, Michio

    2015-06-14

    Some may say that PV modules are moving toward being a simple commodity, but most major PV customers ask: 'How can I minimize chances of a module recall?' Or, 'How can I quantify the added value of a 'premium' module?' Or, 'How can I assess the value of an old PV system that I'm thinking of purchasing?' These are all questions that PVQAT (the International PV Quality Assurance Task Force) and partner organizations are working to answer. Defining standard methods for ensuring minimal acceptable quality of PV modules, differentiating modules that provide added value in the toughest of environments, and creating a process (e.g. through IECRE [1]) that can follow a PV system from design through installation and operation are tough tasks, but having standard approaches for these will increase confidence, reduce costs, and be a critical foundation of a mature PV industry. This paper summarizes current needs for new tests, some challenges for defining those tests, and some of the key efforts toward development of international standards, emphasizing that meaningful quantification of reliability (as in defining a service life prediction) must be done in the context of a specific product with design parameters defined through a quality management system.

  11. Quantifying Reliability - The Next Step for a Rapidly Maturing PV Industry and China's Role

    SciTech Connect

    Kurtz, Sarah

    2015-10-14

    PV customers wish to know how long their PV modules will last, but quantitatively predicting service life is difficult because of the large number of ways that a module can fail, the variability of the use environment, the cost of the testing, and the short product development time, especially when compared with the long desired lifetime. China should play a key role in developing international standards because China manufactures most of the world's PV modules. The presentation will describe the steps that need to be taken to create a service life prediction within the context of a defined bill of materials, process window and use environment. Worldwide standards for cost-effective approaches to service-life predictions will be beneficial to both PV customers and manufacturers since the consequences of premature module failure can be disastrous for both.

  12. Evolution of integrated panel structural design and interfaces for PV power plants

    NASA Astrophysics Data System (ADS)

    Arnett, J. C.; Anderson, A. J.; Robertson, R. E.

    1983-11-01

    The evolution of integrated photovoltaic (PV) panel design at ARCO Solar is discussed. Historically, framed PV modules of about 1 x 4-ft size were individually mounted in the field on fixed support structures and interconnected electrically with cables to build higher-power arrays. When ARCO Solar saw the opportunity in 1982 to marry its PV modules with state-of-the-art heliostat trackers developed by ARCO Power Systems, it became obvious that mounting individual modules was impractical. For this project, the framed modules were factory-assembled into panels and interconnected with cables before being mounted on the trackers. Since then, ARCO Solar made considerable progress and gained substantial experience in the design and fabrication of large PV panels. Constraints and criteria considered in these design activities included static and dynamic loads; assembly and transportation equipment and logistics, structural and electrical interfaces, and safety and grounding concerns.

  13. Evolution of integrated panel structural design and interfaces for PV power plants

    NASA Technical Reports Server (NTRS)

    Arnett, J. C.; Anderson, A. J.; Robertson, R. E.

    1983-01-01

    The evolution of integrated photovoltaic (PV) panel design at ARCO Solar is discussed. Historically, framed PV modules of about 1 x 4-ft size were individually mounted in the field on fixed support structures and interconnected electrically with cables to build higher-power arrays. When ARCO Solar saw the opportunity in 1982 to marry its PV modules with state-of-the-art heliostat trackers developed by ARCO Power Systems, it became obvious that mounting individual modules was impractical. For this project, the framed modules were factory-assembled into panels and interconnected with cables before being mounted on the trackers. Since then, ARCO Solar made considerable progress and gained substantial experience in the design and fabrication of large PV panels. Constraints and criteria considered in these design activities included static and dynamic loads; assembly and transportation equipment and logistics, structural and electrical interfaces, and safety and grounding concerns.

  14. Electrochemical Approaches to PV Busbar Application

    SciTech Connect

    Pankow, J. W.

    2005-01-01

    Busbars are an integral component of any thin-film photovoltaic module and must be easy and quick to apply by PV manufacturers, as well as provide long-term reliability in deployed modules. Potential reliability issues include loss of adhesion and delamination, chemical instability under current collection conditions (electromigration or corrosion), compatibility of material and application method with subsequent encapsulation steps. Several new and novel busbar materials and application methods have been explored, including adhering metal busbars with various one- and two-part conductive epoxies or conductive adhesive films, ultrasonic bonding of metal busbar strips, and bonding of busbar strips using low-temperature solders. The most promising approach to date has been the direct application of metal busbars via various electrochemical techniques, which offers a variety of distinct advantages.

  15. Cost of energy from utility-scale PV systems

    SciTech Connect

    Stolte, W.J.; Whisnant, R.A.; McGowin, C.R.

    1994-12-31

    The cost of energy produced by three different photovoltaic (PV) power plants was estimated based on PV cell and module technology expected to be available by 1995. Plant designs were created for two high concentration PV plants (500 suns), both based on advanced back-contact silicon cell technology, and a thin-film, flat plate plant using copper indium diselenide (CIS) cell technology. The concentrator plants included a central receiver plant using stretched-membrane heliostats and a Fresnel-lens module plant, both utilizing two-axis tracking. Basic plant design factors were selected to minimize 30-year levelized energy costs. Total capital requirements to construct the three plants were estimated through detailed cost estimates. Costs of the cell and module components of the plants were determined by modeling their manufacturing processes when producing modules at an annual rate of both 25 MW/year and 100 MW/year. Energy outputs were determined by computer modeling with hourly insolation and temperature profiles for the two sites. Power system simulation studies were carried out to estimate the impact of the PV plants on system power production cost using synthetic, but realistic, utility system definitions. Both high and low growth rate utility system expansion plans were considered, and capacity and energy credits were calculated. Additionally, credits were calculated for environmental externalities. Benefit/cost ratios for each plant and site were determined. The results of the study provide projections in 1990 dollars of the cost of electric energy from utility-scale PV plants assuming a mature technology that may be available by about 1995. The cost of energy produced by the CIS flat plate plant was projected to be as low as 10.8 cents/kWh. The concentrator plant results were only slightly higher at 12.3 cents/kWh for the Fresnel lens plant and 13.1 cents/kWh for the central receiver plant. 18 refs., 11 figs., 7 tabs.

  16. I-V Curves from Photovoltaic Modules Deployed in Tucson

    NASA Astrophysics Data System (ADS)

    Kopp, Emily; Brooks, Adria; Lonij, Vincent; Cronin, Alex

    2011-10-01

    More than 30 Mega Watts of photo-voltaic (PV) modules are connected to the electric power grid in Tucson, AZ. However, predictions of PV system electrical yields are uncertain, in part because PV modules degrade at various rates (observed typically in the range 0% to 3 %/yr). We present I-V curves (PV output current as a function of PV output voltage) as a means to study PV module efficiency, de-ratings, and degradation. A student-made I-V curve tracer for 100-Watt modules will be described. We present I-V curves for several different PV technologies operated at an outdoor test yard, and we compare new modules to modules that have been operated in the field for 10 years.

  17. Design and Performance of a Hybrid PV/T Solar Water Heater

    NASA Astrophysics Data System (ADS)

    Tripanagnostopoulos, Y.; Souliotis, M.; Makris, Th.; Georgostathis, P.; Sarris, M.

    2010-01-01

    In this paper we present design considerations and experimental results of a thermosyphonic hybrid PV/T solar system that is investigated at the University of Patras. Hybrid PV/T systems can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We tested outdoors PV/T prototypes consisted of pc-Si PV modules and heat exchanger of copper sheet with copper pipes, for two system types (PVT/UNGL and PVT/GL). We used commercial PV modules, which give about 12%-15% efficiency, depending on the operating temperature and the use or not of additional glazing. During the experiments the generated electricity was transmitted to a load, simulating real system operation. Steady state tests of the system were performed outdoors to determine collector thermal efficiency. The glazed PV/T collector presents remarkably higher thermal output than the unglazed PV/T collector, but the electrical output of it is reduced due to additional optical losses. The experimental study of the tested thermosyphonic hybrid PV/T solar device showed that it can perform effectively during all year long, achieving at least 40° C of hot water and producing electricity at a satisfactory level.

  18. Multi-PV technologies method for parameters estimation of two-diode model

    NASA Astrophysics Data System (ADS)

    Sallem, Souhir; Marrekchi, Amal; Kammoun, Soulaymen; Ben Ali Kammoun, Mohamed

    2016-12-01

    Researches are showing that photovoltaic cell equivalent model parameters are not constant and are sensitive to climatic conditions changes. An improved algorithm for multi-photovoltaic cells manufacturing technologies to estimate those parameters is presented in this paper. The method allows a dynamic model for the PV cell according to different climatic conditions. This method shows a better performance of the model for several technologies (poly-crystalline, mono-crystalline and amorphous) of the PV module. Simulated I - V curves are compared to experimental characteristics and other estimation methods for different PV modules and different technologies. Some considerations about the impact of the variations of these resistances on the PV module performance are drawn.

  19. Improved PV system reliability results from surge evaluations at Sandia National Laboratories

    SciTech Connect

    Russell H. Bonn; Sigifredo Gonzalez

    2000-04-11

    Electrical surges on ac and dc inverter power wiring and diagnostic cables have the potential to shorten the lifetime of power electronics. These surges may be caused by either nearby lightning or capacitor switching transients. This paper contains a description of ongoing surge evaluations of PV power electronics and surge mitigation hardware at Sandia.

  20. PV solar electricity: status and future

    NASA Astrophysics Data System (ADS)

    Hoffmann, Winfried

    2006-04-01

    of new concepts to broaden the product portfolio in coming years). The second topic outlines the most likely development of liberalized electricity markets in various regions worldwide. It will be emphasized that in such markets the future prices for electricity will more and more reflect the different cost for bulk and peak power production. This will not only happen for industrial electricity customers - as already today in many countries - but also for private households. The third topic summarizes the existing data and facts by correlating peak power demand and prices traded in various stock exchange markets with delivered PV kWh. It will be shown that a high degree of correlation is existent. Combining the three topics and postulating reverse net metering the competitiveness of PV solar electricity as described is most likely to occur. The described price decrease of modules will also have a very positive impact on off-grid rural applications, mainly in 3rd world countries. It will be shown that this is strongly advanced due to the development of mini-grids starting from solar home systems - with mini grids looking very similar to on-grid applications in weak grid areas of nowadays electricity network.

  1. Estimation of PV energy production based on satellite data

    NASA Astrophysics Data System (ADS)

    Mazurek, G.

    2015-09-01

    Photovoltaic (PV) technology is an attractive source of power for systems without connection to power grid. Because of seasonal variations of solar radiation, design of such a power system requires careful analysis in order to provide required reliability. In this paper we present results of three-year measurements of experimental PV system located in Poland and based on polycrystalline silicon module. Irradiation values calculated from results of ground measurements have been compared with data from solar radiation databases employ calculations from of satellite observations. Good convergence level of both data sources has been shown, especially during summer. When satellite data from the same time period is available, yearly and monthly production of PV energy can be calculated with 2% and 5% accuracy, respectively. However, monthly production during winter seems to be overestimated, especially in January. Results of this work may be helpful in forecasting performance of similar PV systems in Central Europe and allow to make more precise forecasts of PV system performance than based only on tables with long time averaged values.

  2. Locational Sensitivity Investigation on PV Hosting Capacity and Fast Track PV Screening

    SciTech Connect

    Ding, Fei; Mather, Barry; Ainsworth, Nathan; Gotseff, Peter; Baker, Kyri

    2016-05-05

    A 15% PV penetration threshold is commonly used by utilities to define photovoltaic (PV) screening methods where PV penetration is defined as the ratio of total solar PV capacity on a line section to peak load. However, this method doesn't take into account PV locational impact or feeder characteristics that could strongly change the feeder's capability to host PVs. This paper investigates the impact of PV location and phase connection type on PV hosting capacity, and then proposes a fast-track PV screening approach that leverages various PV hosting capacity metric responding to different PV locations and types. The proposed study could help utilities to evaluate PV interconnection requests and also help increase the PV hosting capacity of distribution feeders without adverse impacts on system voltages.

  3. Scalable Optimization Methods for Distribution Networks With High PV Integration

    SciTech Connect

    Guggilam, Swaroop S.; Dall'Anese, Emiliano; Chen, Yu Christine; Dhople, Sairaj V.; Giannakis, Georgios B.

    2016-07-01

    This paper proposes a suite of algorithms to determine the active- and reactive-power setpoints for photovoltaic (PV) inverters in distribution networks. The objective is to optimize the operation of the distribution feeder according to a variety of performance objectives and ensure voltage regulation. In general, these algorithms take a form of the widely studied ac optimal power flow (OPF) problem. For the envisioned application domain, nonlinear power-flow constraints render pertinent OPF problems nonconvex and computationally intensive for large systems. To address these concerns, we formulate a quadratic constrained quadratic program (QCQP) by leveraging a linear approximation of the algebraic power-flow equations. Furthermore, simplification from QCQP to a linearly constrained quadratic program is provided under certain conditions. The merits of the proposed approach are demonstrated with simulation results that utilize realistic PV-generation and load-profile data for illustrative distribution-system test feeders.

  4. PV system testing and standards

    NASA Astrophysics Data System (ADS)

    DeBlasio, Richard

    1999-03-01

    The U.S. Department of Energy (DOE) PV Program System Performance and Engineering Project is being conducted by The National Renewable Energy Laboratory (NREL), Sandia National Laboratories (SNL), Southwest Technology Development Institute (SWTDI), and Florida Solar Energy Center (FSEC). It provides PV system, subsystem, and component-level technology-performance characterization testing; test-method development and validation; national and international consensus standards and codes development, test-facility product certification, and laboratory-accreditation program implementation; and information exchange and technical assistance to the PV community. Emphasis is placed on reducing technical and infrastructural barriers to system acceptance, reducing life-cycle cost of systems, providing systems-engineering best practices and guidelines, and leading the national effort in performance and reliability testing, and consensus standards, codes, and certification program development and implementation—thereby ensuring that PV systems meet customers' needs and expectations. A summary of project activities, accomplishments, and future plans is provided and highlighted by an overview of PV system test-procedure and standards development.

  5. Comparison of Pyranometers vs. PV Reference Cells for Evaluation of PV Array Performance

    SciTech Connect

    Dunn, L.; Gostein, M.; Emery, K.

    2012-09-01

    As the photovoltaics (PV) industry has grown, the need for accurately monitoring the solar resource of PV power plants has increased. Historically, the PV industry has relied on thermopile pyranometers for irradiance measurements, and a large body of historical irradiance data taken with pyranometers exists. However, interest in PV reference devices is increasing. In this paper, we discuss why PV reference devices are better suited for PV applications, and estimate the typical uncertainties in irradiance measurements made with both pyranometers and PV reference devices. We assert that the quantity of interest in monitoring a PV power plant is the equivalent irradiance under the IEC 60904-3 reference solar spectrum that would produce the same electrical response in the PV array as the incident solar radiation. For PV-plant monitoring applications, we find the uncertainties in irradiance measurements of this type to be on the order of +/-5% for thermopile pyranometers and +/-2.4% for PV reference devices.

  6. Photovoltaic module with removable wind deflector

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

    2013-05-28

    A photovoltaic (PV) module assembly including a PV module, a deflector, and a clip. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes a support arm forming a seat. The deflector defines a front face and a rear face, with the clip extending from either the trailing frame member or the rear face of the deflector. In a mounted state, the deflector is nested within the seat and is releasably mounted to the trailing frame member via the clip. In some embodiments, the support arm forms a second seat, with the PV module assembly providing a second mounted state in which the deflector is in a differing orientation/slope, nested within the second seat and releasably mounted to the trailing frame member via the clip.

  7. Photovoltaic module with removable wind deflector

    DOEpatents

    Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Danning, Matt [Oakland, CA; Culligan, Matthew [Berkeley, CA

    2012-08-07

    A photovoltaic (PV) module assembly including a PV module, a deflector, and a clip. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes a support arm forming a seat. The deflector defines a front face and a rear face, with the clip extending from either the trailing frame member or the rear face of the deflector. In a mounted state, the deflector is nested within the seat and is releasably mounted to the trailing frame member via the clip. In some embodiments, the support arm forms a second seat, with the PV module assembly providing a second mounted state in which the deflector is in a differing orientation/slope, nested within the second seat and releasably mounted to the trailing frame member via the clip.

  8. Photovoltaic module with removable wind deflector

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

    2014-02-18

    A photovoltaic (PV) module assembly including a PV module, a deflector, and a clip. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes a support arm forming a seat. The deflector defines a front face and a rear face, with the clip extending from either the trailing frame member or the rear face of the deflector. In a mounted state, the deflector is nested within the seat and is releasably mounted to the trailing frame member via the clip. In some embodiments, the support arm forms a second seat, with the PV module assembly providing a second mounted state in which the deflector is in a differing orientation/slope, nested within the second seat and releasably mounted to the trailing frame member via the clip.

  9. Modelling of Photovoltaic Module Using Matlab Simulink

    NASA Astrophysics Data System (ADS)

    Afiqah Zainal, Nurul; Ajisman; Razlan Yusoff, Ahmad

    2016-02-01

    Photovoltaic (PV) module consists of numbers of photovoltaic cells that are connected in series and parallel used to generate electricity from solar energy. The characteristics of PV module are different based on the model and environment factors. In this paper, simulation of photovoltaic module using Matlab Simulink approach is presented. The method is used to determine the characteristics of PV module in various conditions especially in different level of irradiations and temperature. By having different values of irradiations and temperature, the results showed the output power, voltage and current of PV module can be determined. In addition, all results from Matlab Simulink are verified with theoretical calculation. This proposed model helps in better understanding of PV module characteristics in various environment conditions.

  10. Progress in PV:BONUS project

    NASA Astrophysics Data System (ADS)

    Spaeth, James J.; Pierce, Lizana K.

    1996-01-01

    The PV:BONUS (Building Opportunities in the U.S. for Photovoltaics) program, to develop photovoltaic products and the associated infrastructure for a sustainable photovoltaic market in the building sector, has attracted a variety of promising projects ranging from integrated modular homes, rooftop integrated photovoltaic systems, dispatchable peak shaving systems, alternating-current module, photovoltaic glazing systems, and curtain wall systems. The mutual commitment by the Department of Energy and the program recipients has inspired diverse partnerships among manufacturers, utilities, construction companies, and universities for the development of niche markets for building-integrated photovoltaics. Many of the photovoltaic systems are currently being demonstrated with market campaigns underway to commercialize these innovative renewable energy, building-integrated products.

  11. Small PV Systems Performance Evaluation at NREL's Outdoor Test Facility Using the PVUSA Power Rating Method

    SciTech Connect

    Adelstein, J.; Sekulic, W.

    2005-11-01

    The PV Systems Performance and Reliability R & D group currently has seven grid-tied 1-2 kilowatt PV systems deployed at NREL's Outdoor Test Facility (OTF) and two 6 kilowatt systems mounted on the roof of NREL's Solar Energy Research Facility (SERF). The systems, which employ several PV module technologies including crystalline silicon (c-Si), amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium diselenide (CIS), are being monitored to determine the long-term performance and reliability of the modules and arrays under actual field conditions. The length of observation ranges from 2 months for our newest system to 11 years for our oldest systems. The annual degradation and seasonal fluctuation of the systems' power output are calculated using the PV for Utility-Scale Applications (PVUSA) power rating regression model.

  12. Modular Power Converters for PV Applications

    SciTech Connect

    Ozpineci, Burak; Tolbert, Leon M

    2012-05-01

    This report describes technical opportunities to serve as parts of a technological roadmap for Shoals Technologies Group in power electronics for PV applications. There are many different power converter circuits that can be used for solar inverter applications. The present applications do not take advantage of the potential for using common modules. We envision that the development of a power electronics module could enable higher reliability by being durable and flexible. Modules would have fault current limiting features and detection circuits such that they can limit the current through the module from external faults and can identify and isolate internal faults such that the remaining modules can continue to operate with only minimal disturbance to the utility or customer. Development of a reliable, efficient, low-cost, power electronics module will be a key enabling technology for harnessing more power from solar panels and enable plug and play operation. Power electronics for computer power supplies, communication equipment, and transportation have all targeted reliability and modularity as key requirements and have begun concerted efforts to replace monolithic components with collections of common smart modules. This is happening on several levels including (1) device level with intelligent control, (2) functional module level, and (3) system module. This same effort is needed in power electronics for solar applications. Development of modular units will result in standard power electronic converters that will have a lower installed and operating cost for the overall system. These units will lead to increased adaptability and flexibility of solar inverters. Incorporating autonomous fault current limiting and reconfiguration capabilities into the modules and having redundant modules will lead to a durable converter that can withstand the rigors of solar power generation for more than 30 years. Our vision for the technology roadmap is that there is no need

  13. Overview of Scientific Issues Involved in Selection of Polymers for PV Applications: Preprint

    SciTech Connect

    Kempe, M.

    2011-07-01

    Encapsulant materials used in photovoltaic (PV) modules serve multiple purposes. They physically hold components in place, provide electrical insulation, reduce moisture ingress, optically couple superstrate materials (e.g., glass) to PV cells, protect components from mechanical stress by mechanically de-coupling components via strain relief, and protect materials from corrosion. To do this, encapsulants must adhere well to all surfaces, remain compliant, and transmit light after exposure to temperature, humidity, and UV radiation histories. Here, a brief review of some of the polymeric materials under consideration for PV applications is provided, with an explanation of some of their advantages and disadvantages.

  14. Overview of Scientific Issues Involved in Selection of Polymers for PV Applications

    SciTech Connect

    Kempe, M.

    2011-01-01

    Encapsulant materials used in photovoltaic (PV) modules serve multiple purposes. They physically hold components in place, provide electrical insulation, reduce moisture ingress, optically couple superstrate materials (e.g., glass) to PV cells, protect components from mechanical stress by mechanically decoupling components via strain relief, and protect materials from corrosion. To do this, encapsulants must adhere well to all surfaces, remain compliant, and transmit light after exposure to temperature, humidity, and UV radiation histories. Here, a brief review of some of the polymeric materials under consideration for PV applications is provided, with an explanation of some of their advantages and disadvantages.

  15. Method of monolithic module assembly

    DOEpatents

    Gee, James M.; Garrett, Stephen E.; Morgan, William P.; Worobey, Walter

    1999-01-01

    Methods for "monolithic module assembly" which translate many of the advantages of monolithic module construction of thin-film PV modules to wafered c-Si PV modules. Methods employ using back-contact solar cells positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The methods of the invention allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

  16. Military Curricula for Vocational & Technical Education. Basic Electricity and Electronics Individualized Learning System. CANTRAC A-100-0010. Module Twelve: Series AC Resistive-Reactive Circuits. Study Booklet.

    ERIC Educational Resources Information Center

    Chief of Naval Education and Training Support, Pensacola, FL.

    This individualized learning module on series alternating current resistive-reactive circuits is one in a series of modules for a course in basic electricity and electronics. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instructional and curriculum development in a civilian setting.…

  17. Military Curricula for Vocational & Technical Education. Basic Electricity and Electronics Individualized Learning System. CANTRAC A-100-0010. Module Fourteen: Parallel AC Resistive-Reactive Circuits. Study Booklet.

    ERIC Educational Resources Information Center

    Chief of Naval Education and Training Support, Pensacola, FL.

    This individualized learning module on parallel alternating current resistive-reaction circuits is one in a series of modules for a course in basic electricity and electronics. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instructional and curriculum development in a civilian…

  18. A multi-module microfluidic platform for continuous pre-concentration of water-soluble ions and separation of oil droplets from oil-in-water (O/W) emulsions using a DC-biased AC electrokinetic technique.

    PubMed

    Das, Dhiman; Phan, Dinh-Tuan; Zhao, Yugang; Kang, Yuejun; Chan, Vincent; Yang, Chun

    2017-03-01

    A novel continuous flow microfluidic platform specifically designed for environmental monitoring of O/W emulsions during an aftermath of oil spills is reported herein. Ionized polycyclic aromatic hydrocarbons which are toxic are readily released from crude oil to the surrounding water phase through the smaller oil droplets with enhanced surface area. Hence, a multi-module microfluidic device is fabricated to form ion enrichment zones in the water phase of O/W emulsions for the ease of detection and to separate micron-sized oil droplets from the O/W emulsions. Fluorescein ions in the water phase are used to simulate the presence of these toxic ions in the O/W emulsion. A DC-biased AC electric field is employed in both modules. In the first module, a nanoporous Nafion membrane is used for activating the concentration polarization effect on the fluorescein ions, resulting in the formation of stable ion enrichment zones in the water phase of the emulsion. A 35.6% amplification of the fluorescent signal is achieved in the ion enrichment zone; corresponding to 100% enrichment of the fluorescent dye concentration. In this module, the main inlet is split into two channels by using a Y-junction so that there are two outlets for the oil droplets. The second module located downstream of the first module consists of two oil droplet entrapment zones at two outlets. By switching on the appropriate electrodes, either one of the two oil droplet entrapment zones can be activated and the droplets can be blocked in the corresponding outlet.

  19. Grid Integrated Distributed PV (GridPV) Version 2.

    SciTech Connect

    Reno, Matthew J.; Coogan, Kyle

    2014-12-01

    This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functio ns are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in th e OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions. Each function i n the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.

  20. Silicon Oxynitride Thin Film Barriers for PV Packaging (Poster)

    SciTech Connect

    del Cueto, J. A.; Glick, S. H.; Terwilliger, K. M.; Jorgensen, G. J.; Pankow, J. W.; Keyes, B. M.; Gedvilas, L. M.; Pern, F. J.

    2006-10-03

    Dielectric, adhesion-promoting, moisture barriers comprised of silicon oxynitride thin film materials (SiOxNy with various material stoichiometric compositions x,y) were applied to: 1) bare and pre-coated soda-lime silicate glass (coated with transparent conductive oxide SnO2:F and/or aluminum), and polymer substrates (polyethylene terephthalate, PET, or polyethylene napthalate, PEN); plus 2) pre- deposited photovoltaic (PV) cells and mini-modules consisting of amorphous silicon (a-Si) and copper indium gallium diselenide (CIGS) thin-film PV technologies. We used plasma enhanced chemical vapor deposition (PECVD) process with dilute silane, nitrogen, and nitrous oxide/oxygen gas mixtures in a low-power (< or = 10 milliW per cm2) RF discharge at ~ 0.2 Torr pressure, and low substrate temperatures < or = 100(degrees)C, over deposition areas ~ 1000 cm2. Barrier properties of the resulting PV cells and coated-glass packaging structures were studied with subsequent stressing in damp-heat exposure at 85(degrees)C/85% RH. Preliminary results on PV cells and coated glass indicate the palpable benefits of the barriers in mitigating moisture intrusion and degradation of the underlying structures using SiOxNy coatings with thicknesses in the range of 100-200 nm.

  1. Lightweight IMM PV Flexible Blanket Assembly

    NASA Technical Reports Server (NTRS)

    Spence, Brian

    2015-01-01

    Deployable Space Systems (DSS) has developed an inverted metamorphic multijunction (IMM) photovoltaic (PV) integrated modular blanket assembly (IMBA) that can be rolled or z-folded. This IMM PV IMBA technology enables a revolutionary flexible PV blanket assembly that provides high specific power, exceptional stowed packaging efficiency, and high-voltage operation capability. DSS's technology also accommodates standard third-generation triple junction (ZTJ) PV device technologies to provide significantly improved performance over the current state of the art. This SBIR project demonstrated prototype, flight-like IMM PV IMBA panel assemblies specifically developed, designed, and optimized for NASA's high-voltage solar array missions.

  2. Potential-induced degradation in photovoltaic modules: a critical review

    SciTech Connect

    Luo, Wei; Khoo, Yong Sheng; Hacke, Peter; Naumann, Volker; Lausch, Dominik; Harvey, Steven P.; Singh, Jai Prakash; Chai, Jing; Wang, Yan; Aberle, Armin G.; Ramakrishna, Seeram

    2017-01-01

    Potential-induced degradation (PID) has received considerable attention in recent years due to its detrimental impact on photovoltaic (PV) module performance under field conditions. Both crystalline silicon (c-Si) and thin-film PV modules are susceptible to PID. While extensive studies have already been conducted in this area, the understanding of the PID phenomena is still incomplete and it remains a major problem in the PV industry. Herein, a critical review of the available literature is given to serve as a one-stop source for understanding the current status of PID research. This paper also aims to provide an overview of future research paths to address PID-related issues. This paper consists of three parts. In the first part, the modelling of leakage current paths in the module package is discussed. The PID mechanisms in both c-Si and thin-film PV modules are also comprehensively reviewed. The second part summarizes various test methods to evaluate PV modules for PID. The last part focuses on studies related to PID in the omnipresent p-type c-Si PV modules. The dependence of temperature, humidity and voltage on the progression of PID is examined. Preventive measures against PID at the cell, module and system levels are illustrated. Moreover, PID recovery in standard p-type c-Si PV modules is also studied. Most of the findings from p-type c-Si PV modules are also applicable to other PV module technologies.

  3. Potential-induced degradation in photovoltaic modules: a critical review

    SciTech Connect

    Luo, Wei; Khoo, Yong Sheng; Hacke, Peter; Naumann, Volker; Lausch, Dominik; Harvey, Steven P.; Singh, Jai Prakash; Chai, Jing; Wang, Yan; Aberle, Armin G.; Ramakrishna, Seeram

    2016-11-21

    Potential-induced degradation (PID) has received considerable attention in recent years due to its detrimental impact on photovoltaic (PV) module performance under field conditions. Both crystalline silicon (c-Si) and thin-film PV modules are susceptible to PID. While extensive studies have already been conducted in this area, the understanding of the PID phenomena is still incomplete and it remains a major problem in the PV industry. Herein, a critical review of the available literature is given to serve as a one-stop source for understanding the current status of PID research. This article also aims to provide an overview of future research paths to address PID-related issues. This paper consists of three parts. In the first part, the modelling of leakage current paths in the module package is discussed. The PID mechanisms in both c-Si and thin-film PV modules are also comprehensively reviewed. The second part summarizes various test methods to evaluate PV modules for PID. The last part focuses on studies related to PID in the omnipresent p-type c-Si PV modules. The dependence of temperature, humidity and voltage on the progression of PID is examined. Preventive measures against PID at the cell, module and system levels are illustrated. Moreover, PID recovery in standard p-type c-Si PV modules is also studied. Most of the findings from p-type c-Si PV modules are also applicable to other PV module technologies.

  4. Final Report Report: Smart Grid Ready PV Inverters with Utility Communication

    SciTech Connect

    Seal, Brian; Huque, Aminul; Rogers, Lindsey; Key, Tom; Riley, Cameron; Li, Huijuan; York, Ben; Purcell, Chris; Pacific, Oliver; Ropp, Michael; Tran, Teresa; Asgeirsson, Hawk; Woodard, Justin; Steffel, Steve

    2016-03-30

    In 2011, EPRI began a four-year effort under the Department of Energy (DOE) SunShot Initiative Solar Energy Grid Integration Systems - Advanced Concepts (SEGIS-AC) to demonstrate smart grid ready inverters with utility communication. The objective of the project was to successfully implement and demonstrate effective utilization of inverters with grid support functionality to capture the full value of distributed photovoltaic (PV). The project leveraged ongoing investments and expanded PV inverter capabilities, to enable grid operators to better utilize these grid assets. Developing and implementing key elements of PV inverter grid support capabilities will increase the distribution system’s capacity for higher penetration levels of PV, while reducing the cost. The project team included EPRI, Yaskawa-Solectria Solar, Spirae, BPL Global, DTE Energy, National Grid, Pepco, EDD, NPPT and NREL. The project was divided into three phases: development, deployment, and demonstration. Within each phase, the key areas included: head-end communications for Distributed Energy Resources (DER) at the utility operations center; methods for coordinating DER with existing distribution equipment; back-end PV plant master controller; and inverters with smart-grid functionality. Four demonstration sites were chosen in three regions of the United States with different types of utility operating systems and implementations of utility-scale PV inverters. This report summarizes the project and findings from field demonstration at three utility sites.

  5. Experimental Performance Investigation of Photovoltaic/Thermal (PV-T) System

    NASA Astrophysics Data System (ADS)

    Ozgoren, M.; Aksoy, M. H.; Bakir, C.; Dogan, S.

    2013-04-01

    Photovoltaic solar cells convert light energy from the sun into electricity. Photovoltaic cells are produced by semi-conducting materials to convert the energy into electricity and during this process heat is absorbed by the solar radiation. This heat causes a loss of electricity generation efficiencies.In this study, an experimental setup was designed and established to test two separate photovoltaic panel systems with alone PV and with water cooling system PV/T to examine the heat effect on PV systems. The absorbed heat energy behind the photovoltaic cell's surface in insulated ambient was removed by means of a water cooling system and the tests for both systems were simultaneously performed along the July 2011. It is found that without active water cooling, the temperature of the PV module was higher during day time and solar cells could only achieve around 8% conversion efficiency. On the other hand, when the PV module was operated with active water cooling condition, the temperature dropped significantly, leading to an increase in the efficiency of solarcells as much as 13.6%. Gained from absorbed solar heat and maximum thermal conversion efficiencies of the system are determined as 49% and 51% for two different mass flow rates. It is observed that water flow rate is effective on the increasing the conversion efficiency as well as absorption and transitionrates of cover glass in PV/T (PV-Thermal) collector, the insulation material and cell efficiency. As a conclusion, the conversion efficiency of the PV system with water cooling might be improved on average about 10%. Therefore, it is recommended that PV system should be designed with most efficient type cooling system to enhance the efficiency and to decrease the payback period.

  6. Three-phase-to-two-phase direct AC-AC converter with three leg structure

    NASA Astrophysics Data System (ADS)

    Kwak, S.-S.

    2014-05-01

    A three-phase-to-two-phase ac-ac converter is, along with a modulation strategy based on the space vector scheme, introduced to directly drive two-phase output ac systems with high input power quality. The converter is capable of synthesising two sinusoidal output voltages with variable output frequency and arbitrary magnitude in quadrature phase-shift as well as sinusoidal input currents.

  7. Heritage Park Facilities PV Project

    SciTech Connect

    Hobaica, Mark

    2013-09-26

    Project Objective: To procure a photovoltaic array (PV) system which will generate approximately 256kW of power to be used for the operations of the Aquatic Complex and the adjacent Senior Facility at the Heritage Park. This project complies with the EERE’s work and objectives by promoting the development and deployment of an energy system that will provide current and future generations with clean, efficient, affordable, and reliable energy.

  8. Method of manufacturing a large-area segmented photovoltaic module

    DOEpatents

    Lenox, Carl

    2013-11-05

    One embodiment of the invention relates to a segmented photovoltaic (PV) module which is manufactured from laminate segments. The segmented PV module includes rectangular-shaped laminate segments formed from rectangular-shaped PV laminates and further includes non-rectangular-shaped laminate segments formed from rectangular-shaped and approximately-triangular-shaped PV laminates. The laminate segments are mechanically joined and electrically interconnected to form the segmented module. Another embodiment relates to a method of manufacturing a large-area segmented photovoltaic module from laminate segments of various shapes. Other embodiments relate to processes for providing a photovoltaic array for installation at a site. Other embodiments and features are also disclosed.

  9. Rooftop PV system. PV:BONUS Phase 3B, final technical report

    SciTech Connect

    1998-11-01

    Under the PV:BONUS Program, ECD and United Solar developed, demonstrated and commercialized two new lightweight, flexible BIPV modules specifically designed as replacements for conventional asphalt shingles and standing seam metal roofing. These modules can be economically and aesthetically integrated into new residential and commercial buildings, and can be used to address the even larger roofing-replacement market. An important design feature of these modules, which minimizes the installation and balance-of-system costs, is their ability to be installed by conventional roofing contractors without special training. The modules are fabricated from high-efficiency, triple-junction spectrum-splitting a-Si alloy solar cells developed by ECD and United Solar. These cells are produced on thin, flexible stainless steel substrates and encapsulated with polymer materials. The Phase 3 program began in August 1995. The principal tasks and goals of this program, which have all been successfully completed by ECD and United Solar, are described in the body and appendices of this report.

  10. Stochastic PV performance/reliability model : preview of alpha version.

    SciTech Connect

    Stein, Joshua S.; Miller, Steven P.

    2010-03-01

    Problem Statement: (1) Uncertainties in PV system performance and reliability impact business decisions - Project cost and financing estimates, Pricing service contracts and guarantees, Developing deployment and O&M strategies; (2) Understanding and reducing these uncertainties will help make the PV industry more competitive (3) Performance has typically been estimated without much attention to reliability of components; and (4) Tools are needed to assess all inputs to the value proposition (e.g., LCOE, cash flow, reputation, etc.). Goals and objectives are: (1) Develop a stochastic simulation model (in GoldSim) that can represent PV system performance as a function of system design, weather, reliability, and O&M policies; (2) Evaluate performance for an example system to quantify sources of uncertainty and identify dominant parameters via a sensitivity study; and (3) Example System - 1 inverter, 225 kW DC Array latitude tilt (90 strings of 12 modules {l_brace}1080 modules{r_brace}), Weather from Tucumcari, NM (TMY2 with annual uncertainty).

  11. PV output smoothing with energy storage.

    SciTech Connect

    Ellis, Abraham; Schoenwald, David Alan

    2012-03-01

    This report describes an algorithm, implemented in Matlab/Simulink, designed to reduce the variability of photovoltaic (PV) power output by using a battery. The purpose of the battery is to add power to the PV output (or subtract) to smooth out the high frequency components of the PV power that that occur during periods with transient cloud shadows on the PV array. The control system is challenged with the task of reducing short-term PV output variability while avoiding overworking the battery both in terms of capacity and ramp capability. The algorithm proposed by Sandia is purposely very simple to facilitate implementation in a real-time controller. The control structure has two additional inputs to which the battery can respond. For example, the battery could respond to PV variability, load variability or area control error (ACE) or a combination of the three.

  12. 46 CFR 153.355 - PV venting systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false PV venting systems. 153.355 Section 153.355 Shipping... Systems § 153.355 PV venting systems. When Table 1 requires a PV venting system, the cargo tank must have a PV valve in its vent line. The PV valve must be located between the tank and any connection...

  13. 46 CFR 153.355 - PV venting systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false PV venting systems. 153.355 Section 153.355 Shipping... Systems § 153.355 PV venting systems. When Table 1 requires a PV venting system, the cargo tank must have a PV valve in its vent line. The PV valve must be located between the tank and any connection...

  14. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato....

  15. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato....

  16. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato....

  17. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato....

  18. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato....

  19. Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

    DOE PAGES

    Xiao, Bailu; Hang, Lijun; Mei, Jun; ...

    2014-09-04

    This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is alsomore » proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.« less

  20. Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

    SciTech Connect

    Xiao, Bailu; Hang, Lijun; Mei, Jun; Riley, Cameron; Tolbert, Leon M.; Ozpineci, Burak

    2014-09-04

    This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is also proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.

  1. Distributed PV Adoption - Sensitivity to Market Factors

    SciTech Connect

    Gagnon, Pieter; Sigrin, Ben

    2016-02-01

    NREL staff used the dSolar (distributed solar) model to forecast the adoption of distributed, behind-the-meter PV through the year 2050 for 9 different scenarios. The scenarios varied in their assumptions about a carbon tax, the cost of PV systems in the future, and what credit would be given for excess generation once current net metering policies expire.

  2. Measurement uncertainty analysis techniques applied to PV performance measurements

    SciTech Connect

    Wells, C.

    1992-10-01

    The purpose of this presentation is to provide a brief introduction to measurement uncertainty analysis, outline how it is done, and illustrate uncertainty analysis with examples drawn from the PV field, with particular emphasis toward its use in PV performance measurements. The uncertainty information we know and state concerning a PV performance measurement or a module test result determines, to a significant extent, the value and quality of that result. What is measurement uncertainty analysis It is an outgrowth of what has commonly been called error analysis. But uncertainty analysis, a more recent development, gives greater insight into measurement processes and tests, experiments, or calibration results. Uncertainty analysis gives us an estimate of the I interval about a measured value or an experiment's final result within which we believe the true value of that quantity will lie. Why should we take the time to perform an uncertainty analysis A rigorous measurement uncertainty analysis: Increases the credibility and value of research results; allows comparisons of results from different labs; helps improve experiment design and identifies where changes are needed to achieve stated objectives (through use of the pre-test analysis); plays a significant role in validating measurements and experimental results, and in demonstrating (through the post-test analysis) that valid data have been acquired; reduces the risk of making erroneous decisions; demonstrates quality assurance and quality control measures have been accomplished; define Valid Data as data having known and documented paths of: Origin, including theory; measurements; traceability to measurement standards; computations; uncertainty analysis of results.

  3. Performance of a multifunctional PV/T hybrid solar window

    SciTech Connect

    Davidsson, Henrik; Perers, Bengt; Karlsson, Bjoern

    2010-03-15

    A building-integrated multifunctional PV/T solar window has been developed and evaluated. It is constructed of PV cells laminated on solar absorbers placed in a window behind the glazing. To reduce the cost of the solar electricity, tiltable reflectors have been introduced in the construction to focus radiation onto the solar cells. The reflectors render the possibility of controlling the amount of radiation transmitted into the building. The insulated reflectors also reduce the thermal losses through the window. A model for simulation of the electric and hot water production was developed. The model can perform yearly energy simulations where different features such as shading of the cells or effects of the glazing can be included or excluded. The simulation can be run with the reflectors in an active, up right, position or in a passive, horizontal, position. The simulation program was calibrated against measurements on a prototype solar window placed in Lund in the south of Sweden and against a solar window built into a single family house, Solgaarden, in Aelvkarleoe in the central part of Sweden. The results from the simulation shows that the solar window annually produces about 35% more electric energy per unit cell area compared to a vertical flat PV module. (author)

  4. Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

    SciTech Connect

    Dall'Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.

    2016-07-01

    This paper considers future distribution networks featuring inverter-interfaced photovoltaic (PV) systems, and addresses the synthesis of feedback controllers that seek real- and reactive-power inverter setpoints corresponding to AC optimal power flow (OPF) solutions. The objective is to bridge the temporal gap between long-term system optimization and real-time inverter control, and enable seamless PV-owner participation without compromising system efficiency and stability. The design of the controllers is grounded on a dual ..epsilon..-subgradient method, while semidefinite programming relaxations are advocated to bypass the non-convexity of AC OPF formulations. Global convergence of inverter output powers is analytically established for diminishing stepsize rules for cases where: i) computational limits dictate asynchronous updates of the controller signals, and ii) inverter reference inputs may be updated at a faster rate than the power-output settling time.

  5. Trimode Power Converter optimizes PV, diesel and battery energy sources

    NASA Astrophysics Data System (ADS)

    Osullivan, George; Bonn, Russell; Bower, Ward

    1994-12-01

    Conservatively, there are 100,000 localities in the world waiting for the benefits that electricity can provide, and many of these are in climates where sunshine is plentiful. With these locations in mind a prototype 30 kW hybrid system has been assembled at Sandia to prove the reliability and economics of photovoltaic, diesel and battery energy sources managed by an autonomous power converter. In the Trimode Power Converter the same power parts, four IGBT's with an isolation transformer and filter components, serve as rectifier and charger to charge the battery from the diesel; as a stand-alone inverter to convert PV and battery energy to AC; and, as a parallel inverter with the diesel-generator to accommodate loads larger than the rating of the diesel. Whenever the diesel is supplying the load, an algorithm assures that the diesel is running at maximum efficiency by regulating the battery charger operating point. Given the profile of anticipated solar energy, the cost of transporting diesel fuel to a remote location and a five year projection of load demand, a method to size the PV array, battery and diesel for least cost is developed.

  6. 26+ Year Old Photovoltaic Power Plant: Degradation and Reliability Evaluation of Crystalline Silicon Modules -- South Array

    NASA Astrophysics Data System (ADS)

    Olakonu, Kolapo

    As the use of photovoltaic (PV) modules in large power plants continues to increase globally, more studies on degradation, reliability, failure modes, and mechanisms of field aged modules are needed to predict module life expectancy based on accelerated lifetime testing of PV modules. In this work, a 26+ year old PV power plant in Phoenix, Arizona has been evaluated for performance, reliability, and durability. The PV power plant, called Solar One, is owned and operated by John F. Long's homeowners association. It is a 200 kW dc, standard test conditions (STC) rated power plant comprised of 4000 PV modules or frameless laminates, in 100 panel groups (rated at 175 kW ac). The power plant is made of two center-tapped bipolar arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the south array and the other thesis presents the results obtained on the north array. Each of these two arrays is made of four sub arrays, the east sub arrays (positive and negative polarities) and the west sub arrays (positive and negative polarities), making up eight sub arrays. The evaluation and analyses of the power plant included in this thesis consists of: visual inspection, electrical performance measurements, and infrared thermography. A possible presence of potential induced degradation (PID) due to potential difference between ground and strings was also investigated. Some installation practices were also studied and found to contribute to the power loss observed in this investigation. The power output measured in 2011 for all eight sub arrays at STC is approximately 76 kWdc and represents a power loss of 62% (from 200 kW to 76 kW) over 26+ years. The 2011 measured power output for the four south sub arrays at STC is 39 kWdc and represents a power

  7. Recovery Act: A Low Cost Spray Deposited Solar PV Anti-Reflection Coating Final Technical Report

    SciTech Connect

    Harvey, Michael D.

    2010-08-30

    PV module glass is typically low iron glass which exhibits extremely low absorption of light at solar wavelengths. However, reflection losses from typical high quality solar glass are about 4.5% of the input solar energy. By applying an antireflection coating to the cover glass of their modules, a PV module maker will gain at least a 3% increase in the light passing through the glass and being converted to electricity. Thus achieving an increase of >3% in electricity output from the modules. This Project focussed on developing a process that deposits a layer of porous silica (SiO2) on glass or plastic components, and testing the necessary subcomponents and subsystems required to demonstrate the commercial technology. This porous layer acts as a broadband single layer AR coating for glass and plastics, with the added benefit of being a hydrophilic surface for low surface soiling.

  8. Updated Proposal for a Guide for Quality Management Systems for PV Manufacturing. Supplemental Requirements to ISO 9001-2008

    SciTech Connect

    Ramu, Govind; Yamamichi, Masaaki; Zhou, Wei; Mikonowicz, Alex; Lokanath, Sumanth; Eguchi, Yoshihito; Norum, Paul; Kurtz, Sarah

    2015-03-01

    The goal of this Technical Specification is to provide a guideline for manufacturers of photovoltaic (PV) modules to produce modules that, once the design is proven to meet the quality and reliability requirements, replicate the design on an industrial scale without compromising its consistency with the requirements.

  9. Hybrid photovoltaic/thermal (PV/T) solar systems simulation with Simulink/Matlab

    SciTech Connect

    da Silva, R.M.; Fernandes, J.L.M.

    2010-12-15

    The purpose of this work consists in thermodynamic modeling of hybrid photovoltaic-thermal (PV/T) solar systems, pursuing a modular strategy approach provided by Simulink/Matlab. PV/T solar systems are a recently emerging solar technology that allows for the simultaneous conversion of solar energy into both electricity and heat. This type of technology present some interesting advantages over the conventional ''side-by-side'' thermal and PV solar systems, such as higher combined electrical/thermal energy outputs per unit area, and a more uniform and aesthetical pleasant roof area. Despite the fact that early research on PV/T systems can be traced back to the seventies, only recently it has gained a renewed impetus. In this work, parametric studies and annual transient simulations of PV/T systems are undertaken in Simulink/Matlab. The obtained results show an average annual solar fraction of 67%, and a global overall efficiency of 24% (i.e. 15% thermal and 9% electrical), for a typical four-person single-family residence in Lisbon, with p-Si cells, and a collector area of 6 m{sup 2}. A sensitivity analysis performed on the PV/T collector suggests that the most important variable that should be addressed to improve thermal performance is the photovoltaic (PV) module emittance. Based on those results, some additional improvements are proposed, such as the use of vacuum, or a noble gas at low-pressure, to allow for the removal of PV cells encapsulation without air oxidation and degradation, and thus reducing the PV module emittance. Preliminary results show that this option allows for an 8% increase on optical thermal efficiency, and a substantial reduction of thermal losses, suggesting the possibility of working at higher fluid temperatures. The higher working temperatures negative effect in electrical efficiency was negligible, due to compensation by improved optical properties. The simulation results are compared with experimental data obtained from other authors

  10. Designing PV Incentive Programs to Promote System Performance: AReview of Current Practice

    SciTech Connect

    Barbose, Galen; Wiser, Ryan; Bolinger, Mark

    2006-11-12

    Some stakeholders continue to voice concerns about the performance of customer-sited photovoltaic (PV) systems, particularly because these systems typically receive financial support through ratepayer- or publicly-funded programs. Although much remains to be understood about the extent and specific causes of poor PV system performance, several studies of the larger programs and markets have shed some light on the issue. An evaluation of the California Energy Commission (CEC)'s Emerging Renewables Program, for example, found that 7% of systems, in a sample of 95, had lower-than-expected power output due to shading or soiling (KEMA 2005). About 3% of a larger sample of 140 systems were not operating at all or were operating well below expected output, due to failed equipment, faulty installation workmanship, and/or a lack of basic maintenance. In a recent evaluation of the other statewide PV incentive program in California, the Self-Generation Incentive Program, 9 of 52 projects sampled were found to have annual capacity factors less than 14.5%, although reasons for these low capacity factors generally were not identified (Itron 2005). Studies of PV systems in Germany and Japan, the two largest PV markets worldwide, have also revealed some performance problems associated with issues such as shading, equipment and installation defects, inverter failure, and deviations from module manufacturers' specifications (Otani et al. 2004, Jahn & Nasse 2004). Although owners of PV systems have an inherent incentive to ensure that their systems perform well, many homeowners and building operators may lack the necessary information and expertise to carry out this task effectively. Given this barrier, and the responsibility of PV incentive programs to ensure that public funds are prudently spent, these programs should (and often do) play a critical role in promoting PV system performance. Performance-based incentives (PBIs), which are based on actual energy production rather than

  11. Terawatt Challenge for Thin-Film PV

    SciTech Connect

    Zweibel, K.

    2005-08-01

    The evolution of PV into one of the world's largest industries is not going to happen without major unforeseen problems. However, this study attempts to address the obvious ones, so that we can put aside the mythology of PV (for example, that it is only ''boutique power'' or that one must pave the world with it to be useful) and get on with changing the world's energy infrastructure. With the years of rapid market growth now under way in PV, the author is sure this will not be the last effort to understand the real potential and pitfalls of meeting the Challenge.

  12. Distributed PV Adoption in Maine Through 2021

    SciTech Connect

    Gagnon, Pieter; Sigrin, Ben

    2015-11-06

    NREL has used its dSolar (distributed solar) model to generate low-medium-high estimates of distributed PV adoption in Maine through 2021. This presentation gives a high-level overview of the model and modeling results.

  13. Review of Photovoltaic Energy Production Using CdTe Thin-Film Modules: Extended Abstract Preprint

    SciTech Connect

    Gessert, T. A.

    2008-09-01

    CdTe has near-optimum bandgap, excellent deposition traits, and leads other technologies in commercial PV module production volume. Better understanding materials properties will accelerate deployment.

  14. PV System Energy Evaluation Method (Presentation)

    SciTech Connect

    Kurtz, S.

    2014-01-01

    This presentation describes a comparison of the "predicted" energy (based on historical weather data) with the "expected" energy (based on the measured weather data) to determine whether a PV system is performing as modeled in order to verify the accuracy of a model. A key factor in defining this energy test is determining the test boundary so that weather variations are not inadvertently included in what is considered to be PV system performance.

  15. Updating Technical Screens for PV Interconnection: Preprint

    SciTech Connect

    Coddington, M.; Ellis, A.; Lynn, K.; Razon, A.; Key, T.; Kroposki, B.; Mather, B.; Hill, R.; Nicole, K.; Smith, J.

    2012-08-01

    Solar photovoltaics (PV) is the dominant type of distributed generation (DG) technology interconnected to electric distribution systems in the United States, and deployment of PV systems continues to increase rapidly. Considering the rapid growth and widespread deployment of PV systems in United States electric distribution grids, it is important that interconnection procedures be as streamlined as possible to avoid unnecessary interconnection studies, costs, and delays. Because many PV interconnection applications involve high penetration scenarios, the process needs to allow for a sufficiently rigorous technical evaluation to identify and address possible system impacts. Existing interconnection procedures are designed to balance the need for efficiency and technical rigor for all DG. However, there is an implicit expectation that those procedures will be updated over time in order to remain relevant with respect to evolving standards, technology, and practical experience. Modifications to interconnection screens and procedures must focus on maintaining or improving safety and reliability, as well as accurately allocating costs and improving expediency of the interconnection process. This paper evaluates the origins and usefulness of the capacity penetration screen, offers potential short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen.

  16. Structural and physical properties of the dust particles in Qatar and their influence on the PV panel performance

    PubMed Central

    Aïssa, Brahim; Isaifan, Rima J.; Madhavan, Vinod E.; Abdallah, Amir A.

    2016-01-01

    Recently, extensive R&D has been conducted, both by industry and academia, to significantly raise the conversion efficiency of commercial photovoltaic (PV) modules. The installation of PV systems aimed at optimizing solar energy yield is primarily dictated by its geographic location and installation design to maximize solar exposure. However, even when these characteristics have been addressed appropriately, there are other factors that adversely affect the performance of PV systems, namely the temperature-induced voltage decrease leading to a PV power loss, and the dust accumulation (soiling). The latter is the lesser acknowledged factor that significantly influences the performance of PV installations especially in the Middle East region. In this paper we report on the investigation of the structural and physical properties of the desert-dust particles in the State of Qatar. The dust particles were collected directly from the PV panels installed in desert environment and characterized by different techniques, including scanning electron, optical and atomic force microscopies, X-ray diffraction, energy-dispersive, UV-Vis, micro-Raman and Fourier transform infrared spectroscopy. The vibrating sample magnetometry analyses were also conducted to study the magnetic properties of the dust particles. The influence of the dust accumulation on the PV panel performance was also presented and discussed. PMID:27526667

  17. Structural and physical properties of the dust particles in Qatar and their influence on the PV panel performance.

    PubMed

    Aïssa, Brahim; Isaifan, Rima J; Madhavan, Vinod E; Abdallah, Amir A

    2016-08-16

    Recently, extensive R&D has been conducted, both by industry and academia, to significantly raise the conversion efficiency of commercial photovoltaic (PV) modules. The installation of PV systems aimed at optimizing solar energy yield is primarily dictated by its geographic location and installation design to maximize solar exposure. However, even when these characteristics have been addressed appropriately, there are other factors that adversely affect the performance of PV systems, namely the temperature-induced voltage decrease leading to a PV power loss, and the dust accumulation (soiling). The latter is the lesser acknowledged factor that significantly influences the performance of PV installations especially in the Middle East region. In this paper we report on the investigation of the structural and physical properties of the desert-dust particles in the State of Qatar. The dust particles were collected directly from the PV panels installed in desert environment and characterized by different techniques, including scanning electron, optical and atomic force microscopies, X-ray diffraction, energy-dispersive, UV-Vis, micro-Raman and Fourier transform infrared spectroscopy. The vibrating sample magnetometry analyses were also conducted to study the magnetic properties of the dust particles. The influence of the dust accumulation on the PV panel performance was also presented and discussed.

  18. Structural and physical properties of the dust particles in Qatar and their influence on the PV panel performance

    NASA Astrophysics Data System (ADS)

    Aïssa, Brahim; Isaifan, Rima J.; Madhavan, Vinod E.; Abdallah, Amir A.

    2016-08-01

    Recently, extensive R&D has been conducted, both by industry and academia, to significantly raise the conversion efficiency of commercial photovoltaic (PV) modules. The installation of PV systems aimed at optimizing solar energy yield is primarily dictated by its geographic location and installation design to maximize solar exposure. However, even when these characteristics have been addressed appropriately, there are other factors that adversely affect the performance of PV systems, namely the temperature-induced voltage decrease leading to a PV power loss, and the dust accumulation (soiling). The latter is the lesser acknowledged factor that significantly influences the performance of PV installations especially in the Middle East region. In this paper we report on the investigation of the structural and physical properties of the desert-dust particles in the State of Qatar. The dust particles were collected directly from the PV panels installed in desert environment and characterized by different techniques, including scanning electron, optical and atomic force microscopies, X-ray diffraction, energy-dispersive, UV-Vis, micro-Raman and Fourier transform infrared spectroscopy. The vibrating sample magnetometry analyses were also conducted to study the magnetic properties of the dust particles. The influence of the dust accumulation on the PV panel performance was also presented and discussed.

  19. Photovoltaic module reliability workshop

    SciTech Connect

    Mrig, L.

    1990-01-01

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986--1990. The reliability Photo Voltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warranties available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the US, PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  20. Photovoltaic module reliability workshop

    NASA Astrophysics Data System (ADS)

    Mrig, L.

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986 to 1990. The reliability photovoltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warrantees available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the U.S., PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  1. Solar PV Manufacturing Cost Model Group: Installed Solar PV System Prices (Presentation)

    SciTech Connect

    Goodrich, A. C.; Woodhouse, M.; James, T.

    2011-02-01

    EERE's Solar Energy Technologies Program is charged with leading the Secretary's SunShot Initiative to reduce the cost of electricity from solar by 75% to be cost competitive with conventional energy sources without subsidy by the end of the decade. As part of this Initiative, the program has funded the National Renewable Energy Laboratory (NREL) to develop module manufacturing and solar PV system installation cost models to ensure that the program's cost reduction targets are carefully aligned with current and near term industry costs. The NREL cost analysis team has leveraged the laboratories' extensive experience in the areas of project finance and deployment, as well as industry partnerships, to develop cost models that mirror the project cost analysis tools used by project managers at leading U.S. installers. The cost models are constructed through a "bottoms-up" assessment of each major cost element, beginning with the system's bill of materials, labor requirements (type and hours) by component, site-specific charges, and soft costs. In addition to the relevant engineering, procurement, and construction costs, the models also consider all relevant costs to an installer, including labor burdens and overhead rates, supply chain costs, and overhead and materials inventory costs, and assume market-specific profits.

  2. Interactive smart battery storage for a PV and wind hybrid energy management control based on conservative power theory

    NASA Astrophysics Data System (ADS)

    Godoy Simões, Marcelo; Davi Curi Busarello, Tiago; Saad Bubshait, Abdullah; Harirchi, Farnaz; Antenor Pomilio, José; Blaabjerg, Frede

    2016-04-01

    This paper presents interactive smart battery-based storage (BBS) for wind generator (WG) and photovoltaic (PV) systems. The BBS is composed of an asymmetric cascaded H-bridge multilevel inverter (ACMI) with staircase modulation. The structure is parallel to the WG and PV systems, allowing the ACMI to have a reduction in power losses compared to the usual solution for storage connected at the DC-link of the converter for WG or PV systems. Moreover, the BBS is embedded with a decision algorithm running real-time energy costs, plus a battery state-of-charge manager and power quality capabilities, making the described system in this paper very interactive, smart and multifunctional. The paper describes how BBS interacts with the WG and PV and how its performance is improved. Experimental results are presented showing the efficacy of this BBS for renewable energy applications.

  3. Design and application of PV power system for 100w to 10kw

    SciTech Connect

    Matlin, R.W.

    1982-06-01

    Photovoltaic systems are economically viable in remote areas where grid power is not available and where power requirements are modest. PV systems provide power for water pumping, navigation aids, and residential electrification. Water pumping applications are projected to provide the largest market. The world's largest PV pumping unit, a 25Kw centrifugal pump system used to irrigate 80 acres of corn in Nebraska, is shown. Volumetric style ''jack pumps'' have been installed in the Upper Volta, and in Arizona. Remote residential AC power systems at the Hopi reservation, and a navigational aid system in the St. Lawrence Seaway are also demonstrated. Life cycle costing has shown that it is preferable to use deep cycle batteries.

  4. Measurement uncertainty analysis techniques applied to PV performance measurements

    SciTech Connect

    Wells, C

    1992-10-01

    The purpose of this presentation is to provide a brief introduction to measurement uncertainty analysis, outline how it is done, and illustrate uncertainty analysis with examples drawn from the PV field, with particular emphasis toward its use in PV performance measurements. The uncertainty information we know and state concerning a PV performance measurement or a module test result determines, to a significant extent, the value and quality of that result. What is measurement uncertainty analysis? It is an outgrowth of what has commonly been called error analysis. But uncertainty analysis, a more recent development, gives greater insight into measurement processes and tests, experiments, or calibration results. Uncertainty analysis gives us an estimate of the I interval about a measured value or an experiment`s final result within which we believe the true value of that quantity will lie. Why should we take the time to perform an uncertainty analysis? A rigorous measurement uncertainty analysis: Increases the credibility and value of research results; allows comparisons of results from different labs; helps improve experiment design and identifies where changes are needed to achieve stated objectives (through use of the pre-test analysis); plays a significant role in validating measurements and experimental results, and in demonstrating (through the post-test analysis) that valid data have been acquired; reduces the risk of making erroneous decisions; demonstrates quality assurance and quality control measures have been accomplished; define Valid Data as data having known and documented paths of: Origin, including theory; measurements; traceability to measurement standards; computations; uncertainty analysis of results.

  5. Performance of PV panels for solar energy conversion at the South Pole

    NASA Astrophysics Data System (ADS)

    Peeran, Syed M.

    Expanding research facilities at the Amundson-Scott South pole station require increased electric power generation. Presently, electric power generation is by diesel generators using the JP8 fuel. As the station is accessible only for a short supply period during the austral summer, there are limitations upon the supply of fuel for power generation. This makes it necessary to seriously consider the use of the renewable energy sources. Although there is no sunlight for six months in the year, abundant solar energy is available during the remaining 6 months because of the clear skies, the clarity of air and the low humidity at the south pole. As the buildings at the south pole are built either without windows or with only porthole type windows, large areas on the walls and the roof are available for mounting the photovoltaic (PV) panels. In addition there is unlimited space around the station for constructing a PV panel 'farm'. In this paper four types of PV panels are evaluated; the 2-axis tracking panels, vertical 1-axis tracking panels, fixed vertical panels on the walls of buildings and mounted outdoors, and fixed horizontal panels on the roofs of the buildings. Equations are developed for the power output in KW/sq. ft and annual energy in kWh/sq. ft for each type of panel. The equations include the effects of the inclination of the sun above the horizon, the movement of the sun around the horizon, the direct, reflected and diffused components of the solar radiation, the characteristics of the solar cells and the types of dc/ac inverters used to interface the output of the cells with the existing ac power. A conceptual design of a 150-kW PV generation system suitable for the south pole is also discussed in this paper.

  6. Potential-induced degradation in photovoltaic modules: a critical review

    DOE PAGES

    Luo, Wei; Khoo, Yong Sheng; Hacke, Peter; ...

    2016-11-21

    Potential-induced degradation (PID) has received considerable attention in recent years due to its detrimental impact on photovoltaic (PV) module performance under field conditions. Both crystalline silicon (c-Si) and thin-film PV modules are susceptible to PID. While extensive studies have already been conducted in this area, the understanding of the PID phenomena is still incomplete and it remains a major problem in the PV industry. Herein, a critical review of the available literature is given to serve as a one-stop source for understanding the current status of PID research. This article also aims to provide an overview of future research pathsmore » to address PID-related issues. This paper consists of three parts. In the first part, the modelling of leakage current paths in the module package is discussed. The PID mechanisms in both c-Si and thin-film PV modules are also comprehensively reviewed. The second part summarizes various test methods to evaluate PV modules for PID. The last part focuses on studies related to PID in the omnipresent p-type c-Si PV modules. The dependence of temperature, humidity and voltage on the progression of PID is examined. Preventive measures against PID at the cell, module and system levels are illustrated. Moreover, PID recovery in standard p-type c-Si PV modules is also studied. Most of the findings from p-type c-Si PV modules are also applicable to other PV module technologies.« less

  7. DOE High Performance Concentrator PV Project

    SciTech Connect

    McConnell, R.; Symko-Davies, M.

    2005-08-01

    Much in demand are next-generation photovoltaic (PV) technologies that can be used economically to make a large-scale impact on world electricity production. The U.S. Department of Energy (DOE) initiated the High-Performance Photovoltaic (HiPerf PV) Project to substantially increase the viability of PV for cost-competitive applications so that PV can contribute significantly to both our energy supply and environment. To accomplish such results, the National Center for Photovoltaics (NCPV) directs in-house and subcontracted research in high-performance polycrystalline thin-film and multijunction concentrator devices with the goal of enabling progress of high-efficiency technologies toward commercial-prototype products. We will describe the details of the subcontractor and in-house progress in exploring and accelerating pathways of III-V multijunction concentrator solar cells and systems toward their long-term goals. By 2020, we anticipate that this project will have demonstrated 33% system efficiency and a system price of $1.00/Wp for concentrator PV systems using III-V multijunction solar cells with efficiencies over 41%.

  8. A study of PV/T collector with honeycomb heat exchanger

    NASA Astrophysics Data System (ADS)

    Hussain, F.; Othman, M. Y. H.; Yatim, B.; Ruslan, H.; Sopian, K.; Ibarahim, Z.

    2013-11-01

    This paper present a study of a single pass photovoltaic/thermal (PV/T) solar collector combined with honeycomb heat exchanger. A PV/T system is a combination of photovoltaic panel and solar thermal components in one integrated system. In order to enhance the performance of the system, a honeycomb heat exchanger is installed horizontally into the channel located under the PV module. Air is used as the heat remover medium. The system is tested with and without the honeycomb at irradiance of 828 W/m2 and mass flow rate spanning from 0.02 kg/s to 0.13 kg/s. It is observed that the aluminum honeycomb is capable of enhancing the thermal efficiency of the system efficiently. At mass flow rate of 0.11 kg/s, the thermal efficiency of the system without honeycomb is 27% and with honeycomb is 87 %. Throughout the range of the mass flow rate, the electrical efficiency of the PV module improved by 0.1 %. The improved design is suitable to be further investigated as solar drying system and space heating.

  9. A wide-gap a-SiC:H PV-powered electrochromic window coating

    SciTech Connect

    Gao, W.; Lee, S.H.; Xu, Y.; Benson, D.K.; Deb, S.K.; Branz, H.M.

    1998-09-01

    The authors report on the first monolithic, amorphous-silicon-based, photovoltaic-powered electrochromic window coating. The coating employs a wide bandgap a-Si{sub 1{minus}x}C{sub x}:H n-i-p photovoltaic (PV) cell as a semitransparent power supply, and a Li{sub y}WO{sub 3}/LiAlF{sub 4}/V{sub 2}O{sub 5} electrochromic (EC) device as an optical-transmittance modulator. The EC device is deposited directly on top of a PV cell that coats a glass substrate. The a-Si{sub 1{minus}x}C{sub x}:H PV cell has a Tauc gap of 2.2 eV and a transmittance of 60--80% over a large portion of the visible light spectrum. The authors reduced the thickness of the device to about 600 {angstrom} while maintaining a 1-sun open-circuit voltage of 0.9 V and short-circuit current of 2 mA/cm{sup 2}. The prototype 16 cm{sup 2} PV/EC device modulates the transmittance by more than 60% over a large portion of the visible spectrum. The coloring and bleaching times of the EC device are approximately 1 minute under normal operating conditions ({+-} 1 volt). A brief description of photoelectrochromic windows study is also given.

  10. Innovative Ballasted Flat Roof Solar PV Racking System

    SciTech Connect

    Peek, Richard T.

    2014-12-15

    The objective of this project was to reduce the cost of racking for PV solar on flat commercial rooftops. Cost reductions would come from both labor savings and material savings related to the installation process. The rack would need to accommodate the majority of modules available on the market. Cascade Engineering has a long history of converting traditional metal type applications over to plastic. Injection molding of plastics have numerous advantages including selection of resin for the application, placing the material exactly where it is needed, designing in features that will speed up the installation process, and weight reduction of the array. A plastic rack would need to meet the requirements of UL2703, Mounting systems, mounting devices, clamping/retention devices, and ground lugs for use with flat-plate photovoltaic modules and panels. Comparing original data to the end of project racking design, racking material costs were reduced 50% and labor costs reduced 64%. The racking product accommodates all 60 and 72 cell panels on the market, meets UL2703 requirements, contributes only 1.3 pounds per square foot of weight to the array, requires little ballast to secure the array, automatically grounds the module when the module is secured, stacks/nests well for shipping/fewer lifts to the roof, provides integrated wire routing, allows water to drain on the roof, and accommodates various seismic roof connections. Project goals were achieved as noted in the original funding application.

  11. Launch packaging options for the photovoltaic power module cargo element

    NASA Technical Reports Server (NTRS)

    Hoberecht, Mark A.; Vogt, Scott T.

    1989-01-01

    The National Aeronautics and Space Administration recently embarked on the Space Station Freedom program, which will utilize the Shuttle Orbiter for transportation to orbit. This task will be accomplished with a number of flights over several years. Each flight is unique in terms of the hardware that is manifested and the method by which it is integrated to form viable cargo elements. Work Package 4 is responsible for the electric power system for Space Station Freedom, and was delegated the authority to develop a photovoltaic (PV) power module cargo element. The PV power module consists of several unique assemblies. The first of these is the combined solar array/beta gimbal assembly. The remaining assemblies form the single combined integrated equipment assembly for each PV power module. These three combined assemblies are packaged into a launch cradle to form the PV power module cargo element, which is placed in the cargo bay of the Shuttle Orbiter for transportation to orbit. Various constraints determine the packaging options for the three PV power module combined assemblies. The size and shape of the combined assemblies in relation to the Shuttle Orbiter cargo bay dimensions and other manifested hardware are ultimately a factor in determining the acceptable packaging schemes for the PV power module cargo element. Several packaging options for the PV power module cargo element are presented. These options are discussed in terms of their impact on the overall flight hardware manifest as determined by the various constraints.

  12. Assuring long-term reliability of concentrator PV systems

    NASA Astrophysics Data System (ADS)

    McConnell, R.; Garboushian, V.; Brown, J.; Crawford, C.; Darban, K.; Dutra, D.; Geer, S.; Ghassemian, V.; Gordon, R.; Kinsey, G.; Stone, K.; Turner, G.

    2009-08-01

    Concentrator PV (CPV) systems have attracted significant interest because these systems incorporate the world's highest efficiency solar cells and they are targeting the lowest cost production of solar electricity for the world's utility markets. Because these systems are just entering solar markets, manufacturers and customers need to assure their reliability for many years of operation. There are three general approaches for assuring CPV reliability: 1) field testing and development over many years leading to improved product designs, 2) testing to internationally accepted qualification standards (especially for new products) and 3) extended reliability tests to identify critical weaknesses in a new component or design. Amonix has been a pioneer in all three of these approaches. Amonix has an internal library of field failure data spanning over 15 years that serves as the basis for its seven generations of CPV systems. An Amonix product served as the test CPV module for the development of the world's first qualification standard completed in March 2001. Amonix staff has served on international standards development committees, such as the International Electrotechnical Commission (IEC), in support of developing CPV standards needed in today's rapidly expanding solar markets. Recently Amonix employed extended reliability test procedures to assure reliability of multijunction solar cell operation in its seventh generation high concentration PV system. This paper will discuss how these three approaches have all contributed to assuring reliability of the Amonix systems.

  13. Analysis techniques used on field degraded photovoltaic modules

    SciTech Connect

    Hund, T.D.; King, D.L.

    1995-09-01

    Sandia National Laboratory`s PV System Components Department performs comprehensive failure analysis of photovoltaic modules after extended field exposure at various sites around the world. A full spectrum of analytical techniques are used to help identify the causes of degradation. The techniques are used to make solder fatigue life predictions for PV concentrator modules, identify cell damage or current mismatch, and measure the adhesive strength of the module encapsulant.

  14. Residential, Commercial, and Utility-Scale Photovoltaic (PV) System Prices in the United States: Current Drivers and Cost-Reduction Opportunities

    SciTech Connect

    Goodrich, A.; James, T.; Woodhouse, M.

    2012-02-01

    The price of photovoltaic (PV) systems in the United States (i.e., the cost to the system owner) has dropped precipitously in recent years, led by substantial reductions in global PV module prices. However, system cost reductions are not necessarily realized or realized in a timely manner by many customers. Many reasons exist for the apparent disconnects between installation costs, component prices, and system prices; most notable is the impact of fair market value considerations on system prices. To guide policy and research and development strategy decisions, it is necessary to develop a granular perspective on the factors that underlie PV system prices and to eliminate subjective pricing parameters. This report's analysis of the overnight capital costs (cash purchase) paid for PV systems attempts to establish an objective methodology that most closely approximates the book value of PV system assets.

  15. Photovoltaic module energy rating methodology development

    SciTech Connect

    Kroposki, B.; Myers, D.; Emery, K.; Mrig, L.; Whitaker, C.; Newmiller, J.

    1996-05-01

    A consensus-based methodology to calculate the energy output of a PV module will be described in this paper. The methodology develops a simple measure of PV module performance that provides for a realistic estimate of how a module will perform in specific applications. The approach makes use of the weather data profiles that describe conditions throughout the United States and emphasizes performance differences between various module types. An industry-representative Technical Review Committee has been assembled to provide feedback and guidance on the strawman and final approach used in developing the methodology.

  16. PV Systems Reliability Final Technical Report.

    SciTech Connect

    Lavrova, Olga; Flicker, Jack David; Johnson, Jay; Armijo, Kenneth Miguel; Gonzalez, Sigifredo; Schindelholz, Eric John; Sorensen, Neil R.; Yang, Benjamin Bing-Yeh

    2015-12-01

    The continued exponential growth of photovoltaic technologies paves a path to a solar-powered world, but requires continued progress toward low-cost, high-reliability, high-performance photovoltaic (PV) systems. High reliability is an essential element in achieving low-cost solar electricity by reducing operation and maintenance (O&M) costs and extending system lifetime and availability, but these attributes are difficult to verify at the time of installation. Utilities, financiers, homeowners, and planners are demanding this information in order to evaluate their financial risk as a prerequisite to large investments. Reliability research and development (R&D) is needed to build market confidence by improving product reliability and by improving predictions of system availability, O&M cost, and lifetime. This project is focused on understanding, predicting, and improving the reliability of PV systems. The two areas being pursued include PV arc-fault and ground fault issues, and inverter reliability.

  17. Real time PV manufacturing diagnostic system

    SciTech Connect

    Kochergin, Vladimir; Crawford, Michael A.

    2015-09-01

    The main obstacle Photovoltaic (PV) industry is facing at present is the higher cost of PV energy compared to that of fossil energy. While solar cell efficiencies continue to make incremental gains these improvements are so far insufficient to drive PV costs down to match that of fossil energy. Improved in-line diagnostics however, has the potential to significantly increase the productivity and reduce cost by improving the yield of the process. On this Phase I/Phase II SBIR project MicroXact developed and demonstrated at CIGS pilot manufacturing line a high-throughput in-line PV manufacturing diagnostic system, which was verified to provide fast and accurate data on the spatial uniformity of thickness, an composition of the thin films comprising the solar cell as the solar cell is processed reel-to-reel. In Phase II project MicroXact developed a stand-alone system prototype and demonstrated the following technical characteristics: 1) ability of real time defect/composition inconsistency detection over 60cm wide web at web speeds up to 3m/minute; 2) Better than 1mm spatial resolution on 60cm wide web; 3) an average better than 20nm spectral resolution resulting in more than sufficient sensitivity to composition imperfections (copper-rich and copper-poor regions were detected). The system was verified to be high vacuum compatible. Phase II results completely validated both technical and economic feasibility of the proposed concept. MicroXact’s solution is an enabling technique for in-line PV manufacturing diagnostics to increase the productivity of PV manufacturing lines and reduce the cost of solar energy, thus reducing the US dependency on foreign oil while simultaneously reducing emission of greenhouse gasses.

  18. Large-Scale PV Integration Study

    SciTech Connect

    Lu, Shuai; Etingov, Pavel V.; Diao, Ruisheng; Ma, Jian; Samaan, Nader A.; Makarov, Yuri V.; Guo, Xinxin; Hafen, Ryan P.; Jin, Chunlian; Kirkham, Harold; Shlatz, Eugene; Frantzis, Lisa; McClive, Timothy; Karlson, Gregory; Acharya, Dhruv; Ellis, Abraham; Stein, Joshua; Hansen, Clifford; Chadliev, Vladimir; Smart, Michael; Salgo, Richard; Sorensen, Rahn; Allen, Barbara; Idelchik, Boris

    2011-07-29

    This research effort evaluates the impact of large-scale photovoltaic (PV) and distributed generation (DG) output on NV Energy’s electric grid system in southern Nevada. It analyzes the ability of NV Energy’s generation to accommodate increasing amounts of utility-scale PV and DG, and the resulting cost of integrating variable renewable resources. The study was jointly funded by the United States Department of Energy and NV Energy, and conducted by a project team comprised of industry experts and research scientists from Navigant Consulting Inc., Sandia National Laboratories, Pacific Northwest National Laboratory and NV Energy.

  19. Updating Interconnection Screens for PV System Integration

    SciTech Connect

    Coddington, M.; Mather, B.; Kroposki, B.; Lynn, K.; Razon, A.; Ellis, A.; Hill, R.; Key, T.; Nicole, K.; Smith, J.

    2012-02-01

    This white paper evaluates the origins and usefulness of the capacity penetration screen, offer short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen. Short-term and longer-term alternatives approaches are offered as examples; however, specific modifications to screening procedures should be discussed with stakeholders and must ultimately be adopted by state and federal regulatory bodies.

  20. PV Cephei: Young Star Caught Speeding?

    NASA Astrophysics Data System (ADS)

    Goodman, Alyssa A.; Arce, Héctor G.

    2004-06-01

    Three independent lines of evidence imply that the young star PV Cep is moving at roughly 20 km s-1 through the interstellar medium. The first and strongest suggestion of motion comes from the geometry of the Herbig-Haro (HH) knots in the ``giant'' HH flow associated with PV Cep. Bisectors of lines drawn between pairs of knots at nearly equal distances from PV Cep imply an east-west motion of the source, and a plasmon model fitted to the knot positions gives a good fit of 22 km s-1 motion for the star. The second bit of damning evidence comes from a redshifted trail of molecular gas pointing in the same east-west direction implied by the HH knot geometry. The third exhibit we offer in accusing PV Cep of speeding involves the apparent tilt in the high-velocity molecular jet now emanating from the star. This tilt is best explained if the true, current jet direction is north-south, as it is in Hubble Space Telescope WFPC2 images, and the star is moving, again at roughly 20 km s-1. Tracing the motion of PV Cep backward in time to the nearest cluster from which it might have been ejected, we find that it is very likely to have been thrown out of the massive star-forming cluster NGC 7023, more than 10 pc away. PV Cep and NGC 7023 are at similar distances, and the backward trace of PV Cep's motion is astonishingly well aligned with a dark, previously unexplained rift in NGC 7023. We propose that PV Cep was ejected, at a speed large enough to escape NGC 7023, at least 100,000 yr ago but that it did not enter the molecular cloud in which it now finds itself until more like 35,000 yr ago. Our calculations show that the currently observable molecular outflow associated with PV Cep is about 10,000 yr old, so the flow has had plenty of time to form while in its current molecular cloud. However, the question of what PV Cep was doing and what gas/disk it took along with it in the time it was traveling through the low-density region between NGC 7023 and its current home is an open

  1. PV Ceph: Young Star Caught Speeding?

    NASA Astrophysics Data System (ADS)

    Goodman, A. A.; Arce, H. G.

    2003-12-01

    Three independent lines of evidence imply that the young star PV Ceph is moving at roughly 20 km s-1 through the interstellar medium. The first, and strongest, suggestion of motion comes from the geometry of the HH knots in the ``giant" Herbig-Haro flow associated with PV Ceph. Bisectors of lines drawn between pairs of knots at nearly equal distances from PV Ceph imply an E-W motion of the source, and a plasmon model fit to the knot positions gives a good fit of 22 km s-1 motion for the star. The second bit of damning evidence comes from a redshifted ``trail" of molecular gas, pointing in the same E-W direction implied by the HH knot geometry. The third exhibit we offer in accusing PV Ceph of speeding involves the tilt apparent in the high-velocity molecular jet now emanating from the star. This tilt is best explained if the true, current, jet direction is N-S, as it is in HST WFPC images, and the star is moving--again at roughly 20 km s-1. Tracing the motion of PV Ceph backward in time, to the nearest cluster from which it might have been ejected, we find that it is very likely to have been thrown out of the massive star-forming cluster NGC7023--more than 10 pc away. PV Ceph and NGC7023 are at similar distances, and the backward-trace of PV Ceph's motion is astonishingly well-aligned with a dark, previously unexplained, rift in NGC7023. We propose that PV Ceph was ejected, at a speed large enough to escape NGC7023, at least 100,000 years ago, but that it did not enter the molecular cloud in which it now finds itself until more like 10,000 years ago. Our calculations show that currently-observable molecular outflow associated with PV Ceph is about 10,000 years old, so that the flow has had plenty of time to form while in its current molecular cloud. But, the question of what PV Ceph was doing, and what gas/disk it took along with it in the time it was traveling through the low-density region between NGC7023 and its current home is open to question. Recent numerical

  2. Comparison of four MPPT techniques for PV systems

    NASA Astrophysics Data System (ADS)

    Atik, L.; Petit, P.; Sawicki, J. P.; Ternifi, Z. T.; Bachir, G.; Aillerie, M.

    2016-07-01

    The working behavior of a module / PV array is non-linear and highly dependent on working conditions. As a given condition, there is only one point at which the level of available power at its output is maximum. This point varies with time, enlightenment and temperature. To ensure optimum operation, the use of MPPT control allows us to extract the maximum power. This paper presents a comparative study of four widely-adopted MPPT algorithms, such as Perturb and Observe, Incremental Conductance, Measurements of the variation of the open circuit voltage or of the short-circuit current. Their performance is evaluated using, for all these techniques. In particular, this study compares the behaviors of each technique in presence of solar irradiation variations and temperature fluctuations. These MPPT techniques will be compared using the Matlab / Simulink tool.

  3. Simulation, measurement, and emulation of photovoltaic modules using high frequency and high power density power electronic circuits

    NASA Astrophysics Data System (ADS)

    Erkaya, Yunus

    The number of solar photovoltaic (PV) installations is growing exponentially, and to improve the energy yield and the efficiency of PV systems, it is necessary to have correct methods for simulation, measurement, and emulation. PV systems can be simulated using PV models for different configurations and technologies of PV modules. Additionally, different environmental conditions of solar irradiance, temperature, and partial shading can be incorporated in the model to accurately simulate PV systems for any given condition. The electrical measurement of PV systems both prior to and after making electrical connections is important for attaining high efficiency and reliability. Measuring PV modules using a current-voltage (I-V) curve tracer allows the installer to know whether the PV modules are 100% operational. The installed modules can be properly matched to maximize performance. Once installed, the whole system needs to be characterized similarly to detect mismatches, partial shading, or installation damage before energizing the system. This will prevent any reliability issues from the onset and ensure the system efficiency will remain high. A capacitive load is implemented in making I-V curve measurements with the goal of minimizing the curve tracer volume and cost. Additionally, the increase of measurement resolution and accuracy is possible via the use of accurate voltage and current measurement methods and accurate PV models to translate the curves to standard testing conditions. A move from mechanical relays to solid-state MOSFETs improved system reliability while significantly reducing device volume and costs. Finally, emulating PV modules is necessary for testing electrical components of a PV system. PV emulation simplifies and standardizes the tests allowing for different irradiance, temperature and partial shading levels to be easily tested. Proper emulation of PV modules requires an accurate and mathematically simple PV model that incorporates all known

  4. U.S. Residential Photovoltaic (PV) System Prices, Q4 2013 Benchmarks: Cash Purchase, Fair Market Value, and Prepaid Lease Transaction Prices

    SciTech Connect

    Davidson, C.; James, T. L.; Margolis, R.; Fu, R.; Feldman, D.

    2014-10-01

    The price of photovoltaic (PV) systems in the United States (i.e., the cost to the system owner) has dropped precipitously in recent years, led by substantial reductions in global PV module prices. This report provides a Q4 2013 update for residential PV systems, based on an objective methodology that closely approximates the book value of a PV system. Several cases are benchmarked to represent common variation in business models, labor rates, and module choice. We estimate a weighted-average cash purchase price of $3.29/W for modeled standard-efficiency, polycrystalline-silicon residential PV systems installed in the United States. This is a 46% decline from the 2013-dollar-adjusted price reported in the Q4 2010 benchmark report. In addition, this report frames the cash purchase price in the context of key price metrics relevant to the continually evolving landscape of third-party-owned PV systems by benchmarking the minimum sustainable lease price and the fair market value of residential PV systems.

  5. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  6. 1366 Project Silicon: Reclaiming US Silicon PV Leadership

    SciTech Connect

    Lorenz, Adam

    2016-02-16

    1366 Technologies’ Project Silicon addresses two of the major goals of the DOE’s PV Manufacturing Initiative Part 2 program: 1) How to reclaim a strong silicon PV manufacturing presence and; 2) How to lower the levelized cost of electricity (“LCOE”) for solar to $0.05-$0.07/kWh, enabling wide-scale U.S. market adoption. To achieve these two goals, US companies must commercialize disruptive, high-value technologies that are capable of rapid scaling, defensible from foreign competition, and suited for US manufacturing. These are the aims of 1366 Technologies Direct Wafer ™ process. The research conducted during Project Silicon led to the first industrial scaling of 1366’s Direct Wafer™ process – an innovative, US-friendly (efficient, low-labor content) manufacturing process that destroys the main cost barrier limiting silicon PV cost-reductions: the 35-year-old grand challenge of making quality wafers (40% of the cost of modules) without the cost and waste of sawing. The SunPath program made it possible for 1366 Technologies to build its demonstration factory, a key and critical step in the Company’s evolution. The demonstration factory allowed 1366 to build every step of the process flow at production size, eliminating potential risk and ensuring the success of the Company’s subsequent scaling for a 1 GW factory to be constructed in Western New York in 2016 and 2017. Moreover, the commercial viability of the Direct Wafer process and its resulting wafers were established as 1366 formed key strategic partnerships, gained entry into the $8B/year multi-Si wafer market, and installed modules featuring Direct Wafer products – the veritable proving grounds for the technology. The program also contributed to the development of three Generation 3 Direct Wafer furnaces. These furnaces are the platform for copying intelligently and preparing our supply chain – large-scale expansion will not require a bigger machine but more machines. SunPath filled the

  7. Final Technical Report: PV Fault Detection Tool.

    SciTech Connect

    King, Bruce Hardison; Jones, Christian Birk

    2015-12-01

    The PV Fault Detection Tool project plans to demonstrate that the FDT can (a) detect catastrophic and degradation faults and (b) identify the type of fault. This will be accomplished by collecting fault signatures using different instruments and integrating this information to establish a logical controller for detecting, diagnosing and classifying each fault.

  8. Progress Toward a Stabilization and Preconditioning Protocol for Polycrystalline Thin-Film Photovoltaic Modules

    SciTech Connect

    del Cueto, J. A.; Deline, C. A.; Rummel, S. R.; Anderberg, A.

    2010-08-01

    Cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) thin-film photovoltaic (PV) modules can exhibit substantial variation in measured performance depending on prior exposure history. This study examines the metastable performance changes in these PV modules with the goal of establishing standard preconditioning or stabilization exposure procedures to mitigate measured variations prior to current-voltage (IV) measurements.

  9. The NREL Outdoor Accelerated-Weathering Tracking System Photovoltaic Module Exposure Results

    SciTech Connect

    Basso, T. S.

    2000-01-01

    Status results are presented for the Outdoor Accelerated-Weathering Tracking System (OATS) first study on photovoltaic (PV) modules. Studies began in November 1997 on pairs of commercially available crystalline silicon and amorphous silicon (a-Si) PV modules kept at constant resistive load.

  10. Performance Evaluation of a 1.5-kWdc a-Si PV Array Using the PVUSA Power Rating Method at NREL's Outdoor Test Facility

    SciTech Connect

    McNutt, P.; Adelstein, J.; Sekulic, W.

    2005-11-01

    As part of the work conducted in the PV Systems Reliability and Performance R&D Task, a 1.5-kWdc photovoltaic (PV) array consisting of 36 Solarex MST-43MV dual-junction a-Si modules was installed and its performance monitored for almost six years (September 1999 through May 2005) at the National Renewable Energy Laboratory (NREL) Outdoor Test Facility (OTF). This paper describes the system and its performance based on the PV for Utility-Scale Applications (PVUSA) power rating method.

  11. Recent advances in outdoor performance evaluation of PV systems

    SciTech Connect

    Quintana, M.A.; King, D.L.; Cannon, J.E.; Woodworth, J.R.; Boyson, W.E.; Adams, N.P.; Ellibee, D.E.

    1992-12-31

    Sandia`s Photovoltaic Technology Laboratory (PTEL) routinely performs outdoor tests of a variety of one-sun and concentrator PV modules. The authors experience is that while outdoor testing has its own set of problems, it can produce results that are more directly applicable to ``field`` conditions than testing in solar simulators. They have recently improved both the hardware and software at the PTEL to improve their accuracy and to deal with the special set of problems encountered in outdoor testing. Improvements in hardware include a computer-controlled solar tracker that allows us to test arrays up to 21 m{sup 2} in size; infrared imaging of modules; and electronic loads that allow us to test components with outputs up to 1,800 watts. Improvements in software include real-time monitoring of data collection; a relational data base that has improved the reliability of test setups, operations and analyses; and a standardized reporting process that relates module performance to a number of environmental parameters.

  12. Recent advances in outdoor performance evaluation of PV systems

    NASA Astrophysics Data System (ADS)

    Quintana, M. A.; King, D. L.; Cannon, J. E.; Woodworth, J. R.; Boyson, W. E.; Adams, N. P.; Ellibee, D. E.

    Sandia's Photovoltaic Technology Laboratory (PTEL) routinely performs outdoor tests of a variety of one-sun and concentrator PV modules. The authors' experience is that while outdoor testing has its own set of problems, it can produce results that are more directly applicable to 'field' conditions than testing in solar simulators. They have recently improved both the hardware and software at the PTEL to improve their accuracy and to deal with the special set of problems encountered in outdoor testing. Improvements in hardware include a computer-controlled solar tracker that allows us to test arrays up to 21 sq m in size, infrared imaging of modules, and electronic loads that allow us to test components with outputs up to 1,800 watts. Improvements in software include real-time monitoring of data collection; a relational data base that has improved the reliability of test setups, operations, and analyses; and a standardized reporting process that relates module performance to a number of environmental parameters.

  13. Beacons In Brief. P/PV In Brief. Issue 2

    ERIC Educational Resources Information Center

    Blank, Susan; Farley, Chelsea

    2004-01-01

    This second issue in P/PV's "In Brief" series focuses on the San Francisco Beacon Initiative and P/PV's recently released evaluation results. The Beacon Initiative established after-school programs in eight public schools in low-income San Francisco neighborhoods. P/PV's 36-month evaluation examined key developmental and academic outcomes.…

  14. High Resolution PV Power Modeling for Distribution Circuit Analysis

    SciTech Connect

    Norris, B. L.; Dise, J. H.

    2013-09-01

    NREL has contracted with Clean Power Research to provide 1-minute simulation datasets of PV systems located at three high penetration distribution feeders in the service territory of Southern California Edison (SCE): Porterville, Palmdale, and Fontana, California. The resulting PV simulations will be used to separately model the electrical circuits to determine the impacts of PV on circuit operations.

  15. NREL PV AR D 11th review meeting, May 13--15, 1992, Denver Marriott City Center, Denver, Colorado

    SciTech Connect

    Not Available

    1992-01-01

    This is a collection of abstracts from papers presented at the National Renewable Energy Laboratory (NREL) Photovoltaic (PV) research and development review meeting held May 1992. Subject areas covered include solar cell and solar module manufacturing and development, materials, polycrystalline thin films, applications, amorphous silicon, solar cell performance and testing, crystalline silicon and other photovoltaic and safety perspectives. (GHH)

  16. System and method for determining stator winding resistance in an AC motor using motor drives

    DOEpatents

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

  17. AC magnetohydrodynamic microfluidic switch

    SciTech Connect

    Lemoff, A V; Lee, A P

    2000-03-02

    A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. This type of switch can be used to produce complex fluidic routing, which may have multiple applications in {micro}TAS.

  18. Advanced development of PV encapsulants

    NASA Astrophysics Data System (ADS)

    Holley, W.; Agro, S.; Galica, J.; Thoma, L.; White, R.; Yorgensen, R.

    1994-11-01

    This report describes work under Phase 2 of a Photovoltaic Manufacturing Technology project to conduct laboratory problem definition with an emphasis on controlled aging studies to evaluate the influence of various compositional, processing, and operating parameters on ethylene vinyl acetate (EVA) discoloration. In support of future accelerated UV aging studies (AAS) of coupon-sized EVA laminates, an Atlas xenon arc Ci35A Weather-Ometer was procured, installed, and calibrated for temperature and irradiance. In preparing for the AAS studies, UV-visible spectroscopy measurements were performed on various types of low-iron glass, representative of materials used for module superstrates. It was discovered that the transmission spectra of some of the grades in the UV region from 250 to 400 nm was significantly different. Older grades of Solatex and Solite, and StarPhire 'cut off' well below 290 nm, while newer grades of Solatex and Solite, and StarPhire and Airphire greatly reduce the UV transmittance between 280 and 330 nm. Controlled aging studies are presently underway at 0.55 W/m(exp 2), 340 nm, and 100 C, and we expect comparative data on yellowing to be available soon.

  19. Potential-induced degradation of thin-film Si photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Masuda, Atsushi; Hara, Yukiko

    2017-04-01

    Potential-induced degradation (PID) of thin-film Si photovoltaic (PV) modules was investigated. The characteristics of PID phenomena of thin-film Si PV modules are markedly different from those of crystalline Si PV modules. Not only performance loss but also linear-shape and spot-shape delamination was observed after negative voltage application. Recovery from PID was also observed after positive voltage application. However, rapid progression of PID was found after the second negative voltage application after recovery from the initial PID. The root cause of PID of thin-film Si PV modules is thought to be the delamination between a transparent conductive oxide film and a glass substrate. Such degradation accompanied by delamination was also observed in thin-film Si PV modules exposed outside for about 5 years.

  20. PV Manufacturing R&D Project Status and Accomplishments under 'In-Line Diagnostics and Intelligent Processing' and 'Yield, Durability and Reliability': Preprint

    SciTech Connect

    Friedman, D. J.; Mitchell, R. L.; Keyes, B. M.; Bower, W. I.; King, R.; Mazer, J.

    2006-05-01

    The PV Manufacturing R&D (PVMR&D) Project conducts cost-shared research and development programs with U.S. PV industry partners. There are currently two active industry partnership activities. ''In-line Diagnostics and Intelligent Processing'', launched in 2002, supports development of new in-line diagnostics and monitoring with real-time feedback for optimal process control and increased yield in the fabrication of PV modules, systems, and other system components. ''Yield, Durability and Reliability'', launched in late 2004, supports enhancement of PV module, system component, and complete system reliability in high-volume manufacturing. A second key undertaking of the PVMR&D Project is the collection and analysis of module production cost-capacity metrics for the U.S. PV industry. In the period from 1992 through 2005, the average module manufacturing cost in 2005 dollars fell 54% (5.7% annualized) to $2.74/Wp, and the capacity increased 18.6-fold (25% annualized) to 253 MW/yr. An experience curve analysis gives progress ratios of 87% and 81%, respectively, for U.S. silicon and thin-film module production.

  1. Technologies to Increase PV Hosting Capacity in Distribution Feeders

    SciTech Connect

    Ding, Fei; Mather, Barry; Gotseff, Peter

    2016-11-14

    This paper studies the distributed photovoltaic (PV) hosting capacity in distribution feeders by using the stochastic analysis approach. Multiple scenario simulations are conducted to analyze several factors that affect PV hosting capacity, including the existence of voltage regulator, PV location, the power factor of PV inverter and Volt/VAR control. Based on the conclusions obtained from simulation results, three approaches are then proposed to increase distributed PV hosting capacity, which can be formulated as the optimization problem to obtain the optimal solution. All technologies investigated in this paper utilize only existing assets in the feeder and therefore are implementable for a low cost. Additionally, the tool developed for these studies is described.

  2. Technologies to Increase PV Hosting Capacity in Distribution Feeders: Preprint

    SciTech Connect

    Ding, Fei; Mather, Barry; Gotseff, Peter

    2016-08-01

    This paper studies the distributed photovoltaic (PV) hosting capacity in distribution feeders by using the stochastic analysis approach. Multiple scenario simulations are conducted to analyze several factors that affect PV hosting capacity, including the existence of voltage regulator, PV location, the power factor of PV inverter and Volt/VAR control. Based on the conclusions obtained from simulation results, three approaches are then proposed to increase distributed PV hosting capacity, which can be formulated as the optimization problem to obtain the optimal solution. All technologies investigated in this paper utilize only existing assets in the feeder and therefore are implementable for a low cost. Additionally, the tool developed for these studies is described.

  3. Lanai high-density irradiance sensor network for characterizing solar resource variability of MW-scale PV system.

    SciTech Connect

    Stein, Joshua S.; Johnson, Lars; Ellis, Abraham; Kuszmaul, Scott S.

    2012-01-01

    Sandia National Laboratories (Sandia) and SunPower Corporation (SunPower) have completed design and deployment of an autonomous irradiance monitoring system based on wireless mesh communications and a battery operated data acquisition system. The Lanai High-Density Irradiance Sensor Network is comprised of 24 LI-COR{reg_sign} irradiance sensors (silicon pyranometers) polled by 19 RF Radios. The system was implemented with commercially available hardware and custom developed LabVIEW applications. The network of solar irradiance sensors was installed in January 2010 around the periphery and within the 1.2 MW ac La Ola PV plant on the island of Lanai, Hawaii. Data acquired at 1 second intervals is transmitted over wireless links to be time-stamped and recorded on SunPower data servers at the site for later analysis. The intent is to study power and solar resource data sets to correlate the movement of cloud shadows across the PV array and its effect on power output of the PV plant. The irradiance data sets recorded will be used to study the shape, size and velocity of cloud shadows. This data, along with time-correlated PV array output data, will support the development and validation of a PV performance model that can predict the short-term output characteristics (ramp rates) of PV systems of different sizes and designs. This analysis could also be used by the La Ola system operator to predict power ramp events and support the function of the future battery system. This experience could be used to validate short-term output forecasting methodologies.

  4. Spatial Light Amplifier Modulators

    NASA Technical Reports Server (NTRS)

    Eng, Sverre T.; Olsson, N. Anders

    1992-01-01

    Spatial light amplifier modulators (SLAM's) are conceptual devices that effect two-dimensional spatial modulation in optical computing and communication systems. Unlike current spatial light modulators, these provide gain. Optical processors incorporating SLAM's designed to operate in reflection or transmission mode. Each element of planar SLAM array is optical amplifier - surface-emitting diode laser. Array addressed electrically with ac modulating signals superimposed on dc bias currents supplied to lasers. SLAM device provides both desired modulation and enough optical gain to enable splitting of output signal into many optical fibers without excessive loss of power.

  5. Comparative performance testing of photovoltaic modules in tropical climates of Indonesia

    NASA Astrophysics Data System (ADS)

    Rosyid, Oo Abdul

    2016-02-01

    Solar energy is one of the most significant types of the sustainable and renewable energy sources that have been used in Indonesia. Photovoltaic (PV) is known as the direct conversion of the sunlight to electricity energy with the used of solar cells. There are number of different types of solar PV modules, from an ever increasing range of manufacturers. Each of them claims that they are the best for one reason or another. This paper reports the study results of energy yield measurements of different PV module technologies performed at the outdoor testing facility of the Energy Technology Center (B2TE-BPPT) Kawasan Puspiptek Serpong-Indonesia from March 2014 through February 2015. The purposes of the study wereto evaluate and compare the performances of three different PV modules during a medium term outdoor exposure at the tropical climate of Indonesia. Normalized energy yields (Y), module efficiency (η), and performance ratio (PR) were calculated for each module, and the effect of module temperature and solar irradiance on these parameters was investigated. Monocrystalline PV module was better in terms of module efficiency and overall power production. Meanwhile micromorph silicon (uc-Si) showed the lowest module efficiency, but the more power production compared with polycrystalline PV module. Module efficiency and performance ratio showed a decreasing trend with increase of module temperature.

  6. Cascaded Microinverter PV System for Reduced Cost

    SciTech Connect

    Bellus, Daniel R.; Ely, Jeffrey A.

    2013-04-29

    In this project, a team led by Delphi will develop and demonstrate a novel cascaded photovoltaic (PV) inverter architecture using advanced components. This approach will reduce the cost and improve the performance of medium and large-sized PV systems. The overall project objective is to develop, build, and test a modular 11-level cascaded three-phase inverter building block for photovoltaic applications and to develop and analyze the associated commercialization plan. The system will be designed to utilize photovoltaic panels and will supply power to the electric grid at 208 VAC, 60 Hz 3-phase. With the proposed topology, three inverters, each with an embedded controller, will monitor and control each of the cascade sections, reducing costs associated with extra control boards. This report details the final disposition on this project.

  7. Natural genetic variation of Xanthomonas campestris pv. campestris pathogenicity on arabidopsis revealed by association and reverse genetics.

    PubMed

    Guy, Endrick; Genissel, Anne; Hajri, Ahmed; Chabannes, Matthieu; David, Perrine; Carrere, Sébastien; Lautier, Martine; Roux, Brice; Boureau, Tristan; Arlat, Matthieu; Poussier, Stéphane; Noël, Laurent D

    2013-06-04

    ABSTRACT The pathogenic bacterium Xanthomonas campestris pv. campestris, the causal agent of black rot of Brassicaceae, manipulates the physiology and the innate immunity of its hosts. Association genetic and reverse-genetic analyses of a world panel of 45 X. campestris pv. campestris strains were used to gain understanding of the genetic basis of the bacterium's pathogenicity to Arabidopsis thaliana. We found that the compositions of the minimal predicted type III secretome varied extensively, with 18 to 28 proteins per strain. There were clear differences in aggressiveness of those X. campestris pv. campestris strains on two Arabidopsis natural accessions. We identified 3 effector genes (xopAC, xopJ5, and xopAL2) and 67 amplified fragment length polymorphism (AFLP) markers that were associated with variations in disease symptoms. The nature and distribution of the AFLP markers remain to be determined, but we observed a low linkage disequilibrium level between predicted effectors and other significant markers, suggesting that additional genetic factors make a meaningful contribution to pathogenicity. Mutagenesis of type III effectors in X. campestris pv. campestris confirmed that xopAC functions as both a virulence and an avirulence gene in Arabidopsis and that xopAM functions as a second avirulence gene on plants of the Col-0 ecotype. However, we did not detect the effect of any other effector in the X. campestris pv. campestris 8004 strain, likely due to other genetic background effects. These results highlight the complex genetic basis of pathogenicity at the pathovar level and encourage us to challenge the agronomical relevance of some virulence determinants identified solely in model strains. IMPORTANCE The identification and understanding of the genetic determinants of bacterial virulence are essential to be able to design efficient protection strategies for infected plants. The recent availability of genomic resources for a limited number of pathogen

  8. Energy balance of the global photovoltaic (PV) industry--is the PV industry a net electricity producer?

    PubMed

    Dale, Michael; Benson, Sally M

    2013-04-02

    A combination of declining costs and policy measures motivated by greenhouse gas (GHG) emissions reduction and energy security have driven rapid growth in the global installed capacity of solar photovoltaics (PV). This paper develops a number of unique data sets, namely the following: calculation of distribution of global capacity factor for PV deployment; meta-analysis of energy consumption in PV system manufacture and deployment; and documentation of reduction in energetic costs of PV system production. These data are used as input into a new net energy analysis of the global PV industry, as opposed to device level analysis. In addition, the paper introduces a new concept: a model tracking energetic costs of manufacturing and installing PV systems, including balance of system (BOS) components. The model is used to forecast electrical energy requirements to scale up the PV industry and determine the electricity balance of the global PV industry to 2020. Results suggest that the industry was a net consumer of electricity as recently as 2010. However, there is a >50% that in 2012 the PV industry is a net electricity provider and will "pay back" the electrical energy required for its early growth before 2020. Further reducing energetic costs of PV deployment will enable more rapid growth of the PV industry. There is also great potential to increase the capacity factor of PV deployment. These conclusions have a number of implications for R&D and deployment, including the following: monitoring of the energy embodied within PV systems; designing more efficient and durable systems; and deploying PV systems in locations that will achieve high capacity factors.

  9. Regional Soiling Stations for PV: Soling Loss Analysis

    SciTech Connect

    TamizhMani, G.; King, B.; Venkatesan, A.; Deline, Chris; Pavgi, A.; Tatapudi, S.; Kuitche, J.; Chokor, A.; El Asmar, M.

    2016-11-21

    The soiling loss factor (SLF) of photovoltaic (PV) modules/system is an interplay between the dust frequency and intensity of the site, rain frequency and intensity of the site, tilt angle and height of the module installation, and wind speed and humidity of the site. The integrated area of the downward peaks of the SLF time series plots for a year provides the annual soiling loss for the system at each tilt angle. Sandia National Laboratories, in collaboration with Arizona State University, installed five regional soiling stations around the country and collected soiling loss data over a year. Four of these soiling stations are located at the U.S. Department of Energy Regional Test Centers (Florida, Albuquerque, Colorado and Vermont), while the fifth station is located at the Arizona State University Photovoltaic Reliability Lab (Arizona). This paper presents an analysis on the SLF for each test site at ten different tilt angles. Based on the analysis of a yearlong data obtained in 2015, it appears to indicate that the Arizona site experienced the highest annual soiling loss with a significant dependence on the tilt angle while the other four sites experienced a negligibly small annual soiling loss with practically no dependence on the tilt angle.

  10. Advanced development of PV encapsulants. Semiannual technical progress report, June 30, 1995--December 31, 1995

    SciTech Connect

    Holley, W.A.

    1996-06-01

    The goals of the NREL PVMaT program are, among others, to reduce module manufacturing costs and improve the quality, and we might add here the reliability, of manufactured PV products. One component critical to the service life of PV modules is the useful life of the EVA resin-based encapsulant which is employed extensively by module manufacturers on a worldwide basis. This pottant has been in commercial use since 1982, and over that time has proven to be a dependable material from the standpoint of production, module fabrication, and end-use. But despite the widespread acceptance of the EVA resin-based A9918 and similar formulations for PV encapsulation, some module producers, end-users, and investigators have reported a yellowing or browning phenomenon with EVA resin-based encapsulants in the field. Wile the incidence of this discoloration/degradation appeared at comparatively few sites at the time that this present program was conceived, it raised serious concern as to the long term reliability of EVA resin-based encapsulation systems. Consequently, under the NREL PVMaT program, Springborn Laboratories proposed a comprehensive study of the EVA aging and discoloration problem and its possible solution(s). During the first year of this program, accelerated U.V. aging methods were surveyed. On careful review of the various types of accelerated U.V. aging equipment available, an Atlas Ci35A Weather-Ometer Xenon Exposure System was selected as appropriate equipment for this work. The following report summarizes how this accelerated aging technique has been used to develop a family of solutions to the discoloration problem, the most significant of which is a series of EVA-based encapsulants which are resistant to discoloration.

  11. Tevatron AC dipole system

    SciTech Connect

    Miyamoto, R.; Kopp, S.E.; Jansson, A.; Syphers, M.J.; /Fermilab

    2007-06-01

    The AC dipole is an oscillating dipole magnet which can induce large amplitude oscillations without the emittance growth and decoherence. These properties make it a good tool to measure optics of a hadron synchrotron. The vertical AC dipole for the Tevatron is powered by an inexpensive high power audio amplifier since its operating frequency is approximately 20 kHz. The magnet is incorporated into a parallel resonant system to maximize the current. The use of a vertical pinger magnet which has been installed in the Tevatron made the cost relatively inexpensive. Recently, the initial system was upgraded with a more powerful amplifier and oscillation amplitudes up to 2-3{sigma} were achieved with the 980 GeV proton beam. This paper discusses details of the Tevatron AC dipole system and also shows its test results.

  12. Degradation in PV Encapsulation Strength of Attachment: An Interlaboratory Study Towards a Climate-Specific Test

    SciTech Connect

    Miller, David; Annigoni, Eleonora; Ballion, Amal; Bokria, Jayesh G.; Bruckman, Laura S.; Burns, David M.; Chen, Xinxin; Feng, Jiangtao; French, Roger H.; Fowler, Sean; Honeker, Christian C.; Kempe, Michael; Khonkar, Hussam; Kohl, Michael; Perret-Aebi, Laure-Emmanuelle; Phillips, Nancy H.; Scott, Kurt P.; Sculati-Meillaud, Fanny; Wohlgemuth, John

    2016-06-06

    Reduced strength of attachment of the encapsulant resulting from the outdoor environment, including ultraviolet (UV) radiation, may decrease photovoltaic (PV) module lifetime by enabling widespread corrosion of internal components. To date, few studies exist showing how the adhesion of PV components varies with environmental stress. We have conducted an interlaboratory experiment to provide an understanding that will be used to develop climatic specific module tests. Factors examined in the study included the UV light source (lamp type), temperature, and humidity to be proposed for use in accelerated aging tests. A poly (ethylene-co-vinyl acetate) (EVA) formulation often used in veteran PV installations was studied using a compressive shear test - to quantify the strength of attachment at the EVA/glass interface. Replicate laminated glass/polymer/glass coupon specimens were weathered at 12 institutions using a variety of indoor chambers or field aging. Shear strength, shear strain, and toughness were measured using a mechanical load-frame for the compressive shear test, with subsequent optical imaging and electron microscopy of the separated surfaces.

  13. Degradation in PV Encapsulant Strength of Attachment: An Interlaboratory Study Towards a Climate-Specific Test

    SciTech Connect

    Miller, David C.; Annigoni, Eleonora; Ballion, Amal; Bokria, Jayesh G.; Bruckman, Laura S.; Burns, David M.; Chen, Xinxin; Feng, Jiangtao; French, Roger H.; Fowler, Sean; Honeker, Christian C.; Kempe, Michael D.; Khonkar, Hussam; Kohl, Michael; Perret-Aebi, Laure-Emmanuelle; Phillips, Nancy H.; Scott, Kurt P.; Sculati-Meillaud, Fanny; Wohlgemuth, John H.

    2016-11-21

    Reduced strength of attachment of the encapsulant resulting from the outdoor environment, including ultraviolet (UV) radiation, may decrease photovoltaic (PV) module lifetime by enabling widespread corrosion of internal components. To date, few studies exist showing how the adhesion of PV components varies with environmental stress. We have conducted an interlaboratory experiment to provide an understanding that will be used to develop climatic specific module tests. Factors examined in the study included the UV light source (lamp type), temperature, and humidity to be proposed for use in accelerated aging tests. A poly (ethylene-co-vinyl acetate) (EVA) formulation often used in veteran PV installations was studied using a compressive shear test - to quantify the strength of attachment at the EVA/glass interface. Replicate laminated glass/polymer/glass coupon specimens were weathered at 12 institutions using a variety of indoor chambers or field aging. Shear strength, shear strain, and toughness were measured using a mechanical load-frame for the compressive shear test, with subsequent optical imaging and electron microscopy of the separated surfaces.

  14. ACS CCDs daily monitor

    NASA Astrophysics Data System (ADS)

    Sirianni, Marco

    2006-07-01

    This program consists of a set of basic tests to monitor, the read noise, thedevelopment of hot pixels and test for any source of noise in ACS CCDdetectors. The files, biases and dark will be used to create referencefiles for science calibration. This programme will be for the entire lifetime of ACS.For cycle 15 the program will cover 18 months 12.1.06->05.31.08and it has been divied into three different proposal each covering six months.The three poroposal are 11041-11042-11043.

  15. Integrating Solar PV in Utility System Operations

    SciTech Connect

    Mills, A.; Botterud, A.; Wu, J.; Zhou, Z.; Hodge, B-M.; Heany, M.

    2013-10-31

    This study develops a systematic framework for estimating the increase in operating costs due to uncertainty and variability in renewable resources, uses the framework to quantify the integration costs associated with sub-hourly solar power variability and uncertainty, and shows how changes in system operations may affect these costs. Toward this end, we present a statistical method for estimating the required balancing reserves to maintain system reliability along with a model for commitment and dispatch of the portfolio of thermal and renewable resources at different stages of system operations. We estimate the costs of sub-hourly solar variability, short-term forecast errors, and day-ahead (DA) forecast errors as the difference in production costs between a case with “realistic” PV (i.e., subhourly solar variability and uncertainty are fully included in the modeling) and a case with “well behaved” PV (i.e., PV is assumed to have no sub-hourly variability and can be perfectly forecasted). In addition, we highlight current practices that allow utilities to compensate for the issues encountered at the sub-hourly time frame with increased levels of PV penetration. In this analysis we use the analytical framework to simulate utility operations with increasing deployment of PV in a case study of Arizona Public Service Company (APS), a utility in the southwestern United States. In our analysis, we focus on three processes that are important in understanding the management of PV variability and uncertainty in power system operations. First, we represent the decisions made the day before the operating day through a DA commitment model that relies on imperfect DA forecasts of load and wind as well as PV generation. Second, we represent the decisions made by schedulers in the operating day through hour-ahead (HA) scheduling. Peaking units can be committed or decommitted in the HA schedules and online units can be redispatched using forecasts that are improved

  16. Photovoltaic module kit including connector assembly for non-penetrating array installation

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

    2012-10-23

    A PV module kit for non-penetrating rooftop installation, including a plurality of PV modules and a plurality of connectors. Each of the PV modules includes a PV laminate and a frame forming a mounting region assembled thereto. The connectors include a male connector having a male fastener extending from a head, and a female connector having a female fastener assembled within a head. The heads are entirely formed of plastic. The kit provides a mounted array state including a junction at which the mounting region of at least two of the PV modules are aligned and interconnected by engagement of the male connector with the female connector. The so-formed junction is substantially electrically insulated. The plurality of connectors can further include a spacer connector including a head forming a bore sized to slidably receive the male fastener, with all of the connector heads being identical.

  17. Photovoltaic module kit including connector assembly for non-penetrating array installation

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

    2011-11-22

    A PV module kit for non-penetrating rooftop installation, including a plurality of PV modules and a plurality of connectors. Each of the PV modules includes a PV laminate and a frame forming a mounting region assembled thereto. The connectors include a male connector having a male fastener extending from a head, and a female connector having a female fastener assembled within a head. The heads are entirely formed of plastic. The kit provides a mounted array state including a junction at which the mounting region of at least two of the PV modules are aligned and interconnected by engagement of the male connector with the female connector. The so-formed junction is substantially electrically insulated. The plurality of connectors can further include a spacer connector including a head forming a bore sized to slidably receive the male fastener, with all of the connector heads being identical.

  18. Photovoltaic module kit including connector assembly for non-penetrating array installation

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

    2013-12-31

    A PV module kit for non-penetrating rooftop installation, including a plurality of PV modules and a plurality of connectors. Each of the PV modules includes a PV laminate and a frame forming a mounting region assembled thereto. The connectors include a male connector having a male fastener extending from a head, and a female connector having a female fastener assempbled within a head. The heads are entirely formed of plastic. The kit provides a mounted array state including a junction at which the mounting regions of at least two of the PV modules are aligned and interconnected by engagement of the male connector with the female connector. The so-formed junction is substantially electrically insulated. The plurality of connectors can further include a spacer connector including a head forming a bore sized slidably receive the male fastener, with all of the connector heads being identical.

  19. Large-area, high-intensity PV arrays for systems using dish concentrating optics

    SciTech Connect

    Ward, J.S.; Duda, A.; Zweibel, K.; Coutts, T.J.

    1998-09-01

    In this paper, the authors report on efforts to fabricate monolithic interconnected modules (MIMs) using III-V semiconductors with bandgaps appropriate for the terrestrial solar spectrum. The small size of the component cells comprising the MIM allows for operation at extremely high flux densities and relaxes the requirement for a small spot size to be generated by the optics. This makes possible a PV option for the large dish concentrator systems that have been developed by the solar thermal community for use with Stirling engines. Additionally, the highly effective back-surface reflector integrated into the MIM design is an effective tool for thermal management of the array. Development of this technology would radically alter the projections for PV manufacturing capacity because of the potential for extremely high power generation per unit area of semiconductor material.

  20. AC/DC converter

    NASA Astrophysics Data System (ADS)

    Jain, Praveen K.

    1992-08-01

    In a system such as a 20 kHz space station primary electrical power distribution system, power conversion from AC to DC is required. Some of the basic requirements for this conversion are high efficiency, light weight and small volume, regulated output voltage, close to unity input power factor, distortionless input current, soft-starting, low electromagnetic interference, and high reliability. An AC-to-DC converter is disclosed which satisfies the main design objectives of such converters for use in space. The converter of the invention comprises an input transformer, a resonant network, a current controller, a diode rectifier, and an output filter. The input transformer is for connection to a single phase, high frequency, sinusoidal waveform AC voltage source and provides a matching voltage isolating from the AC source. The resonant network converts this voltage to a sinusoidal, high frequency bidirectional current output, which is received by the current controller to provide the desired output current. The diode rectifier is connected in parallel with the current controller to convert the bidirectional current into a unidirectional current output. The output filter is connected to the rectifier to provide an essentially ripple-free, substantially constant voltage DC output.

  1. AC/RF Superconductivity

    SciTech Connect

    Ciovati, Gianluigi

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  2. Matching the characteristics of batteries with solar cell modules

    NASA Astrophysics Data System (ADS)

    Gay, C. F.; Kapur, V. K.; Pyle, B.; Rumburg, J.; Manfredi, A.

    The typical photovoltaic (PV) power system consists currently of one or a few PV modules. Each module contains from 32 to 40 cells. The modules are connected to one or more six-cell (12 V) lead-acid batteries through a voltage regulator or charge controller. Input conditions for design optimization are discussed, taking into account the basic system, the standard solar day and typical variations, and the dependence of PV module performance on insolation and temperature. Problems regarding the matching of the module voltage to battery characteristics are considered, and a description is provided of the results obtained with a module which was designed to satisfy certain requirements. The investigation shows that it is possible to design a photovoltaic generator to match appropriate characteristics of the battery, taking into account the possibility to maintain self-regulation in practical field operations.

  3. PV technology and success of solar electricity in Vietnam

    SciTech Connect

    Dung, T.Q.

    1997-12-31

    Since 1990 the PV Technology and the Solar electricity have been strongly developed in Vietnam. The PV experts of Solarlab have studied and set up an appropriate PV Technology responding to local Market needs. It has not only stood well but has been also transferred to Mali Republic and Lao P.D.R. The PV off grid systems of Solarlab demonstrate good efficiency and low prices. Over 60 solar stations and villages have been built to provide solar lighting for about 3000 families along the country in remote, mountainous areas and islands. 400 families are using stand-alone Solar Home Systems. The Solar electricity has been chosen for Rural Electrification and National Telecommunication Network in remote and mountainous regions. Many International projects in cooperation with FONDEM-France, SELF USA and Governmental PV projects have been realized by Solarlab. The experiences of maintenance, management and finance about PV development in Vietnam are also mentioned.

  4. Electrochemical aging effects in photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Mon, G. R.

    1986-01-01

    Leakage currents were experimentally measured in PV modules undergoing natural aging outdoors, and in PV modules undergoing accelerated aging in laboratory environmental chambers. The significant contributors to module leakage current were identified with a long range goal to develop techniques to reduce or stop module leakage currents. For outdoor aging in general, module leakage current is relatively insensitive to temperature fluctuations, but is very sensitive to moisture effects such as dew, precipitation, and fluctuations in relative humidity. Comparing ethylene vinyl acetate (EVA) and polyvinyl butyral (PVB), module leakage currents are much higher in PVB as compared to EVA for all environmental conditions investigated. Leakage currents proceed in series along two paths, bulk conduction followed by interfacial (surfaces) conduction.

  5. Development of a hardware-based AC microgrid for AC stability assessment

    NASA Astrophysics Data System (ADS)

    Swanson, Robert R.

    As more power electronic-based devices enable the development of high-bandwidth AC microgrids, the topic of microgrid power distribution stability has become of increased interest. Recently, researchers have proposed a relatively straightforward method to assess the stability of AC systems based upon the time-constants of sources, the net bus capacitance, and the rate limits of sources. In this research, a focus has been to develop a hardware test system to evaluate AC system stability. As a first step, a time domain model of a two converter microgrid was established in which a three phase inverter acts as a power source and an active rectifier serves as an adjustable constant power AC load. The constant power load can be utilized to create rapid power flow transients to the generating system. As a second step, the inverter and active rectifier were designed using a Smart Power Module IGBT for switching and an embedded microcontroller as a processor for algorithm implementation. The inverter and active rectifier were designed to operate simultaneously using a synchronization signal to ensure each respective local controller operates in a common reference frame. Finally, the physical system was created and initial testing performed to validate the hardware functionality as a variable amplitude and variable frequency AC system.

  6. Development of a Dispatchable PV Peak Shainv System. PV: Bonus Program - Phase 1 Report. Volume 1

    SciTech Connect

    1995-10-01

    This report summarizes the work performed by Delmarva Power and Light and its subcontractors in Phase 1 of the US Department of Energy's PV:BONUS Program. The purpose of the program is to develop products and systems for buildings which utilize photovoltaic (N) technology. Beginning with a cooperative research effort with the University of Delaware's Center for Energy and Environmental Policy Research Delmarva Power developed and demonstrated the concept of Dispatchable PV Peak Shaving. This concept and the system which resulted horn the development work are unique from other grid-connected PV systems because it combines a PV, battery energy storage, power conversion and control technologies into an integrated package. Phase 1 began in July 1993 with the installation of a test and demonstration system at Delmarva's Northern Division General Office building near Newark, Delaware. Following initial testing throughout the summer and fall of 1993, significant modifications were made under an amendment to the DOE contract. Work on Phase 1 concluded in the early spring of 1995. Significant progress towards the goal of commercializing the system was made during Phase 1, and is summarized. Based on progress in Phase 1, a proposal to continue the work in Phase 2 was submitted to the US DOE in May 1995. A contract amendment and providing funds for the Phase 2 work is expected in July 1995.

  7. A novel fault diagnosis method of PV based-on power loss and I-V characteristics

    NASA Astrophysics Data System (ADS)

    Chen, Y. H.; Liang, R.; Tian, Y.; Wang, F.

    2016-08-01

    The power loss and the changes of internal I-V output characteristics of photovoltaic (PV) module in the typical fault condition were analyzed. We proposed an on-line real time fault diagnosis method for PV module, which takes into account the power loss and the internal I-V characteristics. Taking into account the changes of temperature and irradiation, the running status of the PV module were simulated in real time. Firstly, by comparing the simulated power with the measured power, it could determine whether the abnormal power loss has occurred. Then based on the change of output voltage, it could decide if short-circuit fault has occurred and estimate the number of short circuited cells roughly. Further, the value of fill factor (FF) can be utilized to determine whether aging fault has occurred and to acquire the remaining service life of the module. The results of simulation and experiment show that this method can effectively detect the partial shadow short-circuit fault and aging fault. It proves the feasibility and accuracy of the fault diagnosis method.

  8. A fatal case of poisoning related to new cathinone designer drugs, 4-methoxy PV8, PV9, and 4-methoxy PV9, and a dissociative agent, diphenidine.

    PubMed

    Kudo, Keiko; Usumoto, Yosuke; Kikura-Hanajiri, Ruri; Sameshima, Naomi; Tsuji, Akiko; Ikeda, Noriaki

    2015-09-01

    A woman in her thirties was found dead on a bed. Considerable amounts of "aroma liquid" and "bath salt" products and hypnotic drug tablets were scattered beside the bed. Autopsy showed pulmonary congestion and edema. Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) analyses of "aroma liquid" and "bath salt" products showed the presence of new cathinone designer drugs, 4-methoxy PV8 (4-methoxy PHPP), PV9 (α-POP), and 4-methoxy PV9 (4-methoxy α-POP), and a dissociative agent, diphenidine. Drug screening in stomach contents, blood and hydrolyzed urine of the woman by GC-MS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed the presence of the above 4 types of drugs and 3 types of benzodiazepines, triazolam, flunitrazepam, and nitrazepam, and their metabolites. The above 7 drugs and 3 benzodiazepine metabolites were simultaneously determined by LC-MS/MS after modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) extraction using diazepam-d5 as the internal standard. The concentrations of 4-methoxy PV8, PV9, 4-methoxy PV9, and diphenidine in the femoral blood were 2.69, 0.743, 0.261, and 1.38μg/ml, respectively, which were significantly higher than concentrations reported in previous cases. Alcohol concentration in the femoral blood was 1.52mg/ml. Based on the pathological and toxicological findings, the cause of death was determined to be 3 types of cathinone drugs, 4-methoxy PV8, PV9, and 4-methoxy PV9, and diphenidine poisoning under the influence of 3 benzodiazepines and alcohol.

  9. High throughput manufacturing of thin-film CdTe photovoltaic modules. Annual subcontract report, 16 November 1993--15 November 1994

    SciTech Connect

    Sandwisch, D W

    1995-11-01

    This report describes work performed by Solar Cells, Inc. (SCI), under a 3-year subcontract to advance SCI`s PV manufacturing technologies, reduce module production costs, increase module performance, and provide the groundwork for SCI to expand its commercial production capacities. SCI will meet these objectives in three phases by designing, debugging, and operating a 20-MW/year, automated, continuous PV manufacturing line that produces 60-cm {times} 120-cm thin-film CdTe PV modules. This report describes tasks completed under Phase 1 of the US Department of Energy`s PV Manufacturing Technology program.

  10. Chemotaxis by Pseudomonas syringae pv. tomato.

    PubMed

    Cuppels, Diane A

    1988-03-01

    Optimal laboratory conditions for studying chemotaxis by Pseudomonas syringae pv. tomato were determined by using the Adler capillary tube assay. Although they are not an absolute requirement for chemotaxis, the presence of 0.1 mM EDTA and 1 mM MgCl(2) in the chemotaxis buffer (10 mM potassium phosphate [pH 7.2]) significantly enhanced the response to attractant. The addition of mannitol as an energy source had little effect. The optimal temperature for chemotaxis was 23 degrees C, which is 5 degrees C below the optimal growth temperature for this pathogen. The best response occurred when the bacteria were exposed to attractant for 60 min at a concentration of approximately 5 x 10 CFU/ml. P. syringae pv. tomato was strongly attracted to citric and malic acids, which are the predominant organic acids in tomato fruit. With the exception of asparagine, the major amino acids of tomatoes were weak to moderate attractants. Glucose and fructose, which account for approximately 47% of tomato dry matter, also elicited poor responses. In assays with tomato intercellular fluid and leaf surface water, the bacterial speck pathogen could not chemotactically distinguish between a resistant and a susceptible cultivar of tomato.

  11. Oxynitride Thin Film Barriers for PV Packaging

    SciTech Connect

    Glick, S. H.; delCueto, J. A.; Terwilliger, K. M.; Jorgensen, G. J.; Pankow, J. W.; Keyes, B. M.; Gedvilas, L. M.; Pern, F. J.

    2005-11-01

    Dielectric thin-film barrier and adhesion-promoting layers consisting of silicon oxynitride materials (SiOxNy, with various stoichiometry) were investigated. For process development, films were applied to glass (TCO, conductive SnO2:F; or soda-lime), polymer (PET, polyethylene terephthalate), aluminized soda-lime glass, or PV cell (a-Si, CIGS) substrates. Design strategy employed de-minimus hazard criteria to facilitate industrial adoption and reduce implementation costs for PV manufacturers or suppliers. A restricted process window was explored using dilute compressed gases (3% silane, 14% nitrous oxide, 23% oxygen) in nitrogen (or former mixtures, and 11.45% oxygen mix in helium and/or 99.999% helium dilution) with a worst-case flammable and non-corrosive hazard classification. Method employed low radio frequency (RF) power, less than or equal to 3 milliwatts per cm2, and low substrate temperatures, less than or equal to 100 deg C, over deposition areas less than or equal to 1000 cm2. Select material properties for barrier film thickness (profilometer), composition (XPS/FTIR), optical (refractive index, %T and %R), mechanical peel strength and WVTR barrier performance are presented.

  12. AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT XVI, LEARNING ABOUT AC GENERATOR (ALTERNATOR) PRINCIPLES (PART I).

    ERIC Educational Resources Information Center

    Human Engineering Inst., Cleveland, OH.

    THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATING PRINCIPLES OF ALTERNATING CURRENT GENERATORS USED ON DIESEL POWERED EQUIPMENT. TOPICS ARE REVIEWING ELECTRICAL FUNDAMENTALS, AND OPERATING PRINCIPLES OF ALTERNATORS. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL PROGRAMED TRAINING FILM "AC GENERATORS…

  13. Series-connected shaded modules to address partial shading conditions in SPV systems

    NASA Astrophysics Data System (ADS)

    Pareek, Smita; Dahiya, Ratna

    2016-03-01

    With the progress of technology and reduced cost of PV cells, the PV systems are being installed in many countries, including India. Even though this method of power generation has sufficient potential but its effective utilization is still lacking. This is because the output power of PV cells depends on many factors like insolation, temperature, climate conditions prevailing nearby, aging, using modules from different technologies/manufacturers or partial shading conditions. Among these factors, partial shading causes major reduction in output power despite the size of PV systems. As a result, the produced power is lower than the expected value. The connection of modules to each other has great impact on output power if they are prone to partial shading conditions. In this paper, PV arrays are investigated under partial shading conditions. The results show that partial shading losses can be minimized by connecting shaded modules in series rather than in parallel.

  14. Step-Stress Accelerated Degradation Testing (SSADT) for Photovoltaic (PV) Devices and Cells (Presentation)

    SciTech Connect

    Lee, J.; Elmore, R.; Suh, C.; Jones, W.

    2010-10-01

    Presentation on step-stress accelerated degradation testing (SSADT) for photovoltaics (PV). Developed are a step-stress degradation test (SSADT) for PV reliability tests and a lifetime prediction model for PV products.

  15. SOLERAS: Photovoltaic power systems project. Module failure analysis

    NASA Astrophysics Data System (ADS)

    Huraib, F. S.; Imamura, M. S.; Salim, A. A.; Rao, N.

    1984-10-01

    The SOLERAS Photovoltaic Power System (PVPS) became operational in September 1981. The system has operated satisfactorily and has experienced very little downtime. Early in 1983 some degradation in the photovoltaic (PV) field performance was detected. A series of current voltage (I-V) tests and other analyses eventually uncovered a number of PV modules that have resulted in open circuit type failure in the four cell group, or a half module. As of August 1984, the estimated number of these defective modules in the PV field was 152. In addition, there are a total of 188 defective modules in the storage warehouse, resulting in a total of 340 modules that need repairs. At the current rate of failures (seven half modules per month), an additional 112 modules would be defective by the end of January 1986, resulting in 412 defective modules. This report presents the results of the failure analysis performed during the past several months on the open circuit modules. Background information as related to the module failures and the effects of such failures on the overall PV field power output are provided. In addition, a plan to continue the monitoring of the rate of failure and analyzing the failure mechanisms is presented.

  16. Impact of residential PV adoption on Retail Electricity Rates

    SciTech Connect

    Cai, DWH; Adlakha, S; Low, SH; De Martini, P; Chandy, KM

    2013-11-01

    The price of electricity supplied from home rooftop photo voltaic (PV) solar cells has fallen below the retail price of grid electricity in some areas. A number of residential households have an economic incentive to install rooftop PV systems and reduce their purchases of electricity from the grid. A significant portion of the costs incurred by utility companies are fixed costs which must be recovered even as consumption falls. Electricity rates must increase in order for utility companies to recover fixed costs from shrinking sales bases. Increasing rates will, in turn, result in even more economic incentives for customers to adopt rooftop PV. In this paper, we model this feedback between PV adoption and electricity rates and study its impact on future PV penetration and net-metering costs. We find that the most important parameter that determines whether this feedback has an effect is the fraction of customers who adopt PV in any year based solely on the money saved by doing so in that year, independent of the uncertainties of future years. These uncertainties include possible changes in rate structures such as the introduction of connection charges, the possibility of PV prices dropping significantly in the future, possible changes in tax incentives, and confidence in the reliability and maintainability of PV. (C) 2013 Elsevier Ltd. All rights reserved.

  17. AtPV42a and AtPV42b Redundantly Regulate Reproductive Development in Arabidopsis thaliana

    PubMed Central

    Fang, Lei; Hou, Xingliang; Lee, Li Yen Candy; Liu, Lu; Yan, Xiaojing; Yu, Hao

    2011-01-01

    Background The conserved SNF1/AMPK/SnRK1 complexes are global regulators of metabolic responses in eukaryotes and play a key role in the control of energy balance. Although α-type subunits of the SnRK1 complex have been characterized in several plant species, the biological function of β-type and γ-type subunits remains largely unknown. Here, we characterized AtPV42a and AtPV42b, the two homologous genes in Arabidopsis, which encode cystathionine-β-synthase (CBS) domain-containing proteins that belong to the PV42 class of γ-type subunits of the plant SnRK1 complexes. Methodology/Principal Findings Real-time polymerase chain reaction was performed to examine the expression of AtPV42a and AtPV42b in various tissues. Transgenic plants that expressed artificial microRNAs targeting these two genes were created. Reproductive organ development and fertilization in these plants were examined by various approaches, including histological analysis, scanning electron microscopy, transmission electron microscopy, and phenotypic analyses of reciprocal crosses between wild-type and transgenic plants. We found that AtPV42a and AtPV42b were expressed in various tissues during different developmental stages. Transgenic plants where AtPV42a and AtPV42b were simultaneously silenced developed shorter siliques and reduced seed sets. Such low fertility phenotype resulted from deregulation of late stamen development and impairment of pollen tube attraction conferred by the female gametophyte. Conclusions Our results demonstrate that AtPV42a and AtPV42b play redundant roles in regulating male gametogenesis and pollen tube guidance, indicating that the Arabidopsis SnRK1 complexes might be involved in the control of reproductive development. PMID:21533063

  18. Tracking the global maximum power point of PV arrays under partial shading conditions

    NASA Astrophysics Data System (ADS)

    Fennich, Meryem

    This thesis presents the theoretical and simulation studies of the global maximum power point tracking (MPPT) for photovoltaic systems under partial shading. The main goal is to track the maximum power point of the photovoltaic module so that the maximum possible power can be extracted from the photovoltaic panels. When several panels are connected in series with some of them shaded partially either due to clouds or shadows from neighboring buildings, several local maxima appear in the power vs. voltage curve. A power increment based MPPT algorithm is effective in identifying the global maximum from the several local maxima. Several existing MPPT algorithms are explored and the state-of-the-art power increment method is simulated and tested for various partial shading conditions. The current-voltage and power-voltage characteristics of the PV model are studied under different partial shading conditions, along with five different cases demonstrating how the MPPT algorithm performs when shading switches from one state to another. Each case is supplemented with simulation results. The method of tracking the Global MPP is based on controlling the DC-DC converter connected to the output of the PV array. A complete system simulation including the PV array, the direct current to direct current (DC-DC) converter and the MPPT is presented and tested using MATLAB software. The simulation results show that the MPPT algorithm works very well with the buck converter, while the boost converter needs further changes and implementation.

  19. Dynamic Performance Comparison for MPPT-PV Systems using Hybrid Pspice/Matlab Simulation

    NASA Astrophysics Data System (ADS)

    Aouchiche, N.; Becherif, M.; HadjArab, A.; Aitcheikh, M. S.; Ramadan, H. S.; Cheknane, A.

    2016-10-01

    The power generated by solar photovoltaic (PV) module depends on the surrounding irradiance and temperature. This paper presents a hybrid Matlab™/Pspice™ simulation model of PV system, combined with Cadence software SLPS. The hybridization is performed in order to gain the advantages of both simulation tools such as accuracy and efficiency in both Pspice electronic circuit and Matlab™ mathematical modelling respectively. For this purpose, the PV panel and the boost converter are developed using Pspice™ and hybridized with the mathematical Matlab™ model of maximum power point method controller (MPPT) through SLPS. The main objective is verify the significance of using the proposed hybrid simulation techniques in comparing the different MPPT algorithms such as the perturbation and observation (P&O), incremental of conductance (Inc-Cond) and counter reaction voltage using pilot cell (Pilot-Cell). Various simulations are performed under different atmospheric conditions in order to evaluate the dynamic behaviour for the system under study in terms of stability, efficiency and rapidity.

  20. Building America Case Study: Photovoltaic Systems with Module-Level Power Electronics

    SciTech Connect

    2015-09-01

    Direct current (DC) power optimizers and microinverters (together known as module-level power electronics, or MLPE) are one of the fastest growing market segments in the solar industry. According to GTM Research in The Global PV Inverter Landscape 2015, over 55% of all residential photovoltaic (PV) installations in the United States used some form of MLPE in 2014.

  1. Detection of acid moisture in photovoltaic modules using a dual wavelength pH-sensitive fluorescent dye

    NASA Astrophysics Data System (ADS)

    Asaka, Takashi; Iwami, Kentaro; Taguchi, Atsushi; Umeda, Norihiro; Masuda, Atsushi

    2014-01-01

    The formation of acetic acid via the penetration of moisture into ethylene vinyl acetate (EVA) in photovoltaic (PV) modules is cited as the main reason for PV modules’ degradation. Currently, there is no effective method for detecting acetic moisture in PV modules. We proposed a simple method for detecting acid moisture in PV modules using a dual-wavelength pH-sensitive dye that measures pH by the ratio of the intensities of two peaks in the fluorescence spectra of the dye. We detected the pH change caused by acetic acid with the change in the intensity ratio of the fluorescence spectra of the dried dye. Furthermore, we observed that the dry fluorescent dye is heat resistant to withstand the lamination process for the manufacturing of PV modules, and has good long-term durability.

  2. xopAC-triggered Immunity against Xanthomonas Depends on Arabidopsis Receptor-Like Cytoplasmic Kinase Genes PBL2 and RIPK

    PubMed Central

    Guy, Endrick; Lautier, Martine; Chabannes, Matthieu; Roux, Brice; Lauber, Emmanuelle; Arlat, Matthieu; Noël, Laurent D.

    2013-01-01

    Xanthomonas campestris pv. campestris (Xcc) colonizes the vascular system of Brassicaceae and ultimately causes black rot. In susceptible Arabidopsis plants, XopAC type III effector inhibits by uridylylation positive regulators of the PAMP-triggered immunity such as the receptor-like cytoplasmic kinases (RLCK) BIK1 and PBL1. In the resistant ecotype Col-0, xopAC is a major avirulence gene of Xcc. In this study, we show that both the RLCK interaction domain and the uridylyl transferase domain of XopAC are required for avirulence. Furthermore, xopAC can also confer avirulence to both the vascular pathogen Ralstonia solanacearum and the mesophyll-colonizing pathogen Pseudomonas syringae indicating that xopAC-specified effector-triggered immunity is not specific to the vascular system. In planta, XopAC-YFP fusions are localized at the plasma membrane suggesting that XopAC might interact with membrane-localized proteins. Eight RLCK of subfamily VII predicted to be localized at the plasma membrane and interacting with XopAC in yeast two-hybrid assays have been isolated. Within this subfamily, PBL2 and RIPK RLCK genes but not BIK1 are important for xopAC-specified effector-triggered immunity and Arabidopsis resistance to Xcc. PMID:23951354

  3. 21-kW Thin-Film PV Technology Validation -- An NREL/Solar Energy Centre of India MOU Cooperative Project

    SciTech Connect

    McNutt, P. F.; Ullal, H. S.

    2005-01-01

    This paper summarizes findings during a one-week (27-31 October 2003) site visit to the Thin-Film Technology Test Bed at India's Solar Energy Centre (SEC) near New Delhi. The U.S. and Indian governments signed a Memorandum of Understanding in March 2000 to undertake a 50-50 cost-shared 21-kW thin-film PV technology validation project to evaluate the performance of thin-film photovoltaic (PV) modules under Indian climatic conditions. This project benefits Indian researchers by giving them experience with cost-effective PV materials, and it benefits the United States because data will be sent to the appropriate U.S. thin-film PV manufacturers for evaluation and analysis. During the visit, NREL personnel engaged in technical discussions regarding thin-film PV technologies with Ministry of Non-Conventional Energy Sources engineers and scientists. Issues included inspecting the newly constructed arrays, discussing better methods of electrically loading the PV arrays, taking I-V traces, and gathering baseline I-V data.

  4. Molecular detection of Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv. oryzicola, and Burkholderia glumae in infected rice seeds and leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polymerase chain reaction (PCR) is particularly useful for plant pathogen detection. In the present study, multiplex PCR and SYBR green real-time PCR were developed to facilitate simultaneous detection of three important rice pathogens, Xanthomonas oryzae pv. oryzae, X. oryzae pv. oryzicola, and Bur...

  5. Previous reports of bacterial diseases on crucifers attributed to Pseuomonas syringae pv. maculicola were caused by P. cannabina pv. alisalensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas cannabina pv. alisalensis (Pca) causes bacterial blight on crucifers, which can reduce crucifer yields and result in economic losses in the US. Prior to the late 1990s Pca was not distinguished from the pepper spot pathogen of crucifers, Pseudomonas syringae pv. maculicola (Psm), althoug...

  6. BOLD signal effects of transcranial alternating current stimulation (tACS) in the alpha range: A concurrent tACS-fMRI study.

    PubMed

    Vosskuhl, Johannes; Huster, René J; Herrmann, Christoph S

    2016-10-15

    Many studies have proven transcranial alternating current stimulation (tACS) to manipulate brain activity. Until now it is not known, however, how these manipulations in brain activity are represented in brain metabolism or how spatially specific these changes are. Alpha-tACS has been shown to enhance the amplitude of the individual alpha frequency (IAF) and a negative correlation between alpha amplitude and occipital BOLD signal was reported in numerous EEG/fMRI experiments. Thus, alpha-tACS was chosen to test the effects of tACS on the BOLD signal. A reduction thereof was expected during alpha-tACS which shows the spatial extent of tACS effects beyond modeling studies. Three groups of subjects were measured in an MRI scanner, receiving tACS at either their IAF (N=11), 1Hz (control; N=12) or sham (i.e., no stimulation - a second control; N=11) while responding to a visual vigilance task. Stimulation was administered in an interleaved pattern of tACS-on runs and tACS-free baseline periods. The BOLD signal was analyzed in response to tACS-onset during resting state and in response to seldom target stimuli. Alpha-tACS at 1.0mA reduced the task-related BOLD response to visual targets in the occipital cortex as compared to tACS-free baseline periods. The deactivation was strongest in an area where the BOLD signal was shown to correlate negatively with alpha amplitude. A direct effect of tACS on resting state BOLD signal levels could not be shown. Our findings suggest that tACS-related changes in BOLD activity occur only as a modulation of an existing BOLD response.

  7. Innovations in Wind and Solar PV Financing

    SciTech Connect

    Cory, K.; Coughlin, J.; Jenkin, T.; Pater, J.; Swezey, B.

    2008-02-01

    There is growing national interest in renewable energy development based on the economic, environmental, and security benefits that these resources provide. Historically, greater development of our domestic renewable energy resources has faced a number of hurdles, primarily related to cost, regulation, and financing. With the recent sustained increase in the costs and associated volatility of fossil fuels, the economics of renewable energy technologies have become increasingly attractive to investors, both large and small. As a result, new entrants are investing in renewable energy and new business models are emerging. This study surveys some of the current issues related to wind and solar photovoltaic (PV) energy project financing in the electric power industry, and identifies both barriers to and opportunities for increased investment.

  8. Managing PV Power on Mars - MER Rovers

    NASA Technical Reports Server (NTRS)

    Stella, Paul M.; Chin, Keith; Wood, Eric; Herman, Jennifer; Ewell, Richard

    2009-01-01

    The MER Rovers have recently completed over 5 years of operation! This is a remarkable demonstration of the capabilities of PV power on the Martian surface. The extended mission required the development of an efficient process to predict the power available to the rovers on a day-to-day basis. The performance of the MER solar arrays is quite unlike that of any other Space array and perhaps more akin to Terrestrial PV operation, although even severe by that comparison. The impact of unpredictable factors, such as atmospheric conditions and dust accumulation (and removal) on the panels limits the accurate prediction of array power to short time spans. Based on the above, it is clear that long term power predictions are not sufficiently accurate to allow for detailed long term planning. Instead, the power assessment is essentially a daily activity, effectively resetting the boundary points for the overall predictive power model. A typical analysis begins with the importing of the telemetry from each rover's previous day's power subsystem activities. This includes the array power generated, battery state-of-charge, rover power loads, and rover orientation, all as functions of time. The predicted performance for that day is compared to the actual performance to identify the extent of any differences. The model is then corrected for these changes. Details of JPL's MER power analysis procedure are presented, including the description of steps needed to provide the final prediction for the mission planners. A dust cleaning event of the solar array is also highlighted to illustrate the impact of Martian weather on solar array performance

  9. Lessons Learned from the Photovoltaic Manufacturing Technology/PV Manufacturing R&D and Thin Film PV Partnership Projects

    SciTech Connect

    Margolis, R.; Mitchell, R.; Zweibel, K.

    2006-09-01

    As the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program initiates new cost-shared solar energy R&D under the Solar America Initiative (SAI), it is useful to analyze the experience gained from cost-shared R&D projects that have been funded through the program to date. This report summarizes lessons learned from two DOE-sponsored photovoltaic (PV) projects: the Photovoltaic Manufacturing Technology/PV Manufacturing R&D (PVMaT/PVMR&D) project and the Thin-Film PV Partnership project. During the past 10-15 years, these two projects have invested roughly $330 million of government resources in cost-shared R&D and leveraged another $190 million in private-sector PV R&D investments. Following a description of key findings and brief descriptions of the PVMaT/PVMR&D and Thin-Film PV Partnership projects, this report presents lessons learned from the projects.

  10. NREL PV AR&D 11th review meeting, May 13--15, 1992, Denver Marriott City Center, Denver, Colorado. Photovoltaic Advanced Research and Development Project

    SciTech Connect

    Not Available

    1992-06-01

    This is a collection of abstracts from papers presented at the National Renewable Energy Laboratory (NREL) Photovoltaic (PV) research and development review meeting held May 1992. Subject areas covered include solar cell and solar module manufacturing and development, materials, polycrystalline thin films, applications, amorphous silicon, solar cell performance and testing, crystalline silicon and other photovoltaic and safety perspectives. (GHH)

  11. Phase modulation mode of scanning ion conductance microscopy

    SciTech Connect

    Li, Peng; Zhang, Changlin; Liu, Lianqing E-mail: gli@engr.pitt.edu; Wang, Yuechao; Yang, Yang; Li, Guangyong E-mail: gli@engr.pitt.edu

    2014-08-04

    This Letter reports a phase modulation (PM) mode of scanning ion conductance microscopy. In this mode, an AC current is directly generated by an AC voltage between the electrodes. The portion of the AC current in phase with the AC voltage, which is the current through the resistance path, is modulated by the tip-sample distance. It can be used as the input of feedback control to drive the scanner in Z direction. The PM mode, taking the advantages of both DC mode and traditional AC mode, is less prone to electronic noise and DC drift but maintains high scanning speed. The effectiveness of the PM mode has been proven by experiments.

  12. AC resistance measuring instrument

    DOEpatents

    Hof, P.J.

    1983-10-04

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument. 8 figs.

  13. AC Resistance measuring instrument

    DOEpatents

    Hof, Peter J.

    1983-01-01

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument.

  14. AC Optimal Power Flow

    SciTech Connect

    2016-10-04

    In this work, we have implemented and developed the simulation software to implement the mathematical model of an AC Optimal Power Flow (OPF) problem. The objective function is to minimize the total cost of generation subject to constraints of node power balance (both real and reactive) and line power flow limits (MW, MVAr, and MVA). We have currently implemented the polar coordinate version of the problem. In the present work, we have used the optimization solver, Knitro (proprietary and not included in this software) to solve the problem and we have kept option for both the native numerical derivative evaluation (working satisfactorily now) as well as for analytical formulas corresponding to the derivatives being provided to Knitro (currently, in the debugging stage). Since the AC OPF is a highly non-convex optimization problem, we have also kept the option for a multistart solution. All of these can be decided by the user during run-time in an interactive manner. The software has been developed in C++ programming language, running with GCC compiler on a Linux machine. We have tested for satisfactory results against Matpower for the IEEE 14 bus system.

  15. Interconnecting PV on New York City's Secondary Network Distribution System

    SciTech Connect

    Anderson, K; Coddington, M; Burman, K; Hayter, S; Kroposki, B; Watson, and A

    2009-11-01

    The U.S. Department of Energy (DOE) has teamed with cities across the country through the Solar America Cities (SAC) partnership program to help reduce barriers and accelerate implementation of solar energy. The New York City SAC team is a partnership between the City University of New York (CUNY), the New York City Mayor s Office of Long-term Planning and Sustainability, and the New York City Economic Development Corporation (NYCEDC).The New York City SAC team is working with DOE s National Renewable Energy Laboratory (NREL) and Con Edison, the local utility, to develop a roadmap for photovoltaic (PV) installations in the five boroughs. The city set a goal to increase its installed PV capacity from1.1 MW in 2005 to 8.1 MW by 2015 (the maximum allowed in 2005). A key barrier to reaching this goal, however, is the complexity of the interconnection process with the local utility. Unique challenges are associated with connecting distributed PV systems to secondary network distribution systems (simplified to networks in this report). Although most areas of the country use simpler radial distribution systems to distribute electricity, larger metropolitan areas like New York City typically use networks to increase reliability in large load centers. Unlike the radial distribution system, where each customer receives power through a single line, a network uses a grid of interconnected lines to deliver power to each customer through several parallel circuits and sources. This redundancy improves reliability, but it also requires more complicated coordination and protection schemes that can be disrupted by energy exported from distributed PV systems. Currently, Con Edison studies each potential PV system in New York City to evaluate the system s impact on the network, but this is time consuming for utility engineers and may delay the customer s project or add cost for larger installations. City leaders would like to streamline this process to facilitate faster, simpler, and

  16. Three junction holographic micro-scale PV system

    NASA Astrophysics Data System (ADS)

    Wu, Yuechen; Vorndran, Shelby; Ayala Pelaez, Silvana; Kostuk, Raymond K.

    2016-09-01

    In this work a spectrum splitting micro-scale concentrating PV system is evaluated to increase the conversion efficiency of flat panel PV systems. In this approach, the dispersed spectrum splitting concentration systems is scaled down to a small size and structured in an array. The spectrum splitting configuration allows the use of separate single bandgap PV cells that increase spectral overlap with the incident solar spectrum. This results in an overall increase in the spectral conversion efficiency of the resulting system. In addition other benefits of the micro-scale PV system are retained such reduced PV cell material requirements, more versatile interconnect configurations, and lower heat rejection requirements that can lead to a lower cost system. The system proposed in this work consists of two cascaded off-axis holograms in combination with a micro lens array, and three types of PV cells. An aspherical lens design is made to minimize the dispersion so that higher concentration ratios can be achieved for a three-junction system. An analysis methodology is also developed to determine the optical efficiency of the resulting system, the characteristics of the dispersed spectrum, and the overall system conversion efficiency for a combination of three types of PV cells.

  17. Kauai Island Utility Co-op (KIUC) PV integration study.

    SciTech Connect

    Ellis, Abraham; Mousseau, Tom

    2011-08-01

    This report investigates the effects that increased distributed photovoltaic (PV) generation would have on the Kauai Island Utility Co-op (KIUC) system operating requirements. The study focused on determining reserve requirements needed to mitigate the impact of PV variability on system frequency, and the impact on operating costs. Scenarios of 5-MW, 10-MW, and 15-MW nameplate capacity of PV generation plants distributed across the Kauai Island were considered in this study. The analysis required synthesis of the PV solar resource data and modeling of the KIUC system inertia. Based on the results, some findings and conclusions could be drawn, including that the selection of units identified as marginal resources that are used for load following will change; PV penetration will displace energy generated by existing conventional units, thus reducing overall fuel consumption; PV penetration at any deployment level is not likely to reduce system peak load; and increasing PV penetration has little effect on load-following reserves. The study was performed by EnerNex under contract from Sandia National Laboratories with cooperation from KIUC.

  18. Sub-synchronous resonance damping using high penetration PV plant

    NASA Astrophysics Data System (ADS)

    Khayyatzadeh, M.; Kazemzadeh, R.

    2017-02-01

    The growing need to the clean and renewable energy has led to the fast development of transmission voltage-level photovoltaic (PV) plants all over the world. These large scale PV plants are going to be connected to power systems and one of the important subjects that should be investigated is the impact of these plants on the power system stability. Can large scale PV plants help to damp sub-synchronous resonance (SSR) and how? In this paper, this capability of a large scale PV plant is investigated. The IEEE Second Benchmark Model aggregated with a PV plant is utilized as the case study. A Wide Area Measurement System (WAMS) based conventional damping controller is designed and added to the main control loop of PV plant in order to damp the SSR and also investigation of the destructive effect of time delay in remote feedback signal. A new optimization algorithm called teaching-learning-based-optimization (TLBO) algorithm has been used for managing the optimization problems. Fast Furrier Transformer (FFT) analysis and also transient simulations of detailed nonlinear system are considered to investigate the performance of the controller. Robustness of the proposed system has been analyzed by facing the system with disturbances leading to significant changes in generator and power system operating point, fault duration time and PV plant generated power. All the simulations are carried out in MATLAB/SIMULINK environment.

  19. Optimal Solar PV Arrays Integration for Distributed Generation

    SciTech Connect

    Omitaomu, Olufemi A; Li, Xueping

    2012-01-01

    Solar photovoltaic (PV) systems hold great potential for distributed energy generation by installing PV panels on rooftops of residential and commercial buildings. Yet challenges arise along with the variability and non-dispatchability of the PV systems that affect the stability of the grid and the economics of the PV system. This paper investigates the integration of PV arrays for distributed generation applications by identifying a combination of buildings that will maximize solar energy output and minimize system variability. Particularly, we propose mean-variance optimization models to choose suitable rooftops for PV integration based on Markowitz mean-variance portfolio selection model. We further introduce quantity and cardinality constraints to result in a mixed integer quadratic programming problem. Case studies based on real data are presented. An efficient frontier is obtained for sample data that allows decision makers to choose a desired solar energy generation level with a comfortable variability tolerance level. Sensitivity analysis is conducted to show the tradeoffs between solar PV energy generation potential and variability.

  20. Identification of /sup 233/Ac

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1983-09-01

    We report in this paper identification of the new isotope /sup 233/Ac. Uranium targets were irradiated with 28 GeV protons; after rapid retrieval of the target and separation of actinium from thorium, /sup 233/Ac was allowed to decay into the known /sup 233/Th daughter. Exhaustive chemical purification was employed to permit the identification of /sup 233/Th via its characteristic ..gamma.. radiations. The half-life derived for /sup 233/Ac from several experiments is 2.3 +- 0.3 min. The production cross section for /sup 233/Ac is 100 ..mu..b.

  1. Photovoltaic module certification/laboratory accreditation criteria development

    SciTech Connect

    Osterwald, C.R.; Hammond, R.L.; Wood, B.D.; Backus, C.E.; Sears, R.L.; Zerlaut, G.A.; D`Aiello, R.V.

    1995-04-01

    This document provides an overview of the structure and function of typical product certification/laboratory accreditation programs. The overview is followed by a model program which could serve as the basis for a photovoltaic (PV) module certification/laboratory accreditation program. The model covers quality assurance procedures for the testing laboratory and manufacturer, third-party certification and labeling, and testing requirements (performance and reliability). A 30-member Criteria Development Committee was established to guide, review, and reach a majority consensus regarding criteria for a PV certification/laboratory accreditation program. Committee members represented PV manufacturers, end users, standards and codes organizations, and testing laboratories.

  2. Performance assessment and transient optimization of multi-stage solid desiccant air conditioning systems with building PV/T integration

    NASA Astrophysics Data System (ADS)

    Gadalla, Mohamed; Saghafifar, Mohammad

    2016-09-01

    One of the popular solar air conditioning technologies is desiccant air conditioning. Nonetheless, single stage desiccant air conditioning systems' coefficient of performance (COP) are relatively low. Therefore, multi-stage solid desiccant air conditioning systems are recommended. In this paper, an integrated double-stage desiccant air conditioning systems and PV/T collector is suggested for hot and humid climates such as the UAE. The results for the PV/T implementation in the double-stage desiccant cooling system are assessed against the PV/T results for a single-stage desiccant air conditioning system. In order to provide a valid comparative evaluation between the single and double stage desiccant air conditioning systems, an identical PV/T module, in terms of dimensions, is incorporated into these systems. The overall required auxiliary air heating is abated by 46.0% from 386.8 MWh to 209.0 MWh by replacing the single stage desiccant air conditioning system with the proposed double stage configuration during June to October. Moreover, the overall averaged solar share during the investigated months for the single and double stage systems are 36.5% and 43.3%.

  3. Synergistic combination of valproic acid and oncolytic parvovirus H-1PV as a potential therapy against cervical and pancreatic carcinomas.

    PubMed

    Li, Junwei; Bonifati, Serena; Hristov, Georgi; Marttila, Tiina; Valmary-Degano, Séverine; Stanzel, Sven; Schnölzer, Martina; Mougin, Christiane; Aprahamian, Marc; Grekova, Svitlana P; Raykov, Zahari; Rommelaere, Jean; Marchini, Antonio

    2013-10-01

    The rat parvovirus H-1PV has oncolytic and tumour-suppressive properties potentially exploitable in cancer therapy. This possibility is being explored and results are encouraging, but it is necessary to improve the oncotoxicity of the virus. Here we show that this can be achieved by co-treating cancer cells with H-1PV and histone deacetylase inhibitors (HDACIs) such as valproic acid (VPA). We demonstrate that these agents act synergistically to kill a range of human cervical carcinoma and pancreatic carcinoma cell lines by inducing oxidative stress, DNA damage and apoptosis. Strikingly, in rat and mouse xenograft models, H-1PV/VPA co-treatment strongly inhibits tumour growth promoting complete tumour remission in all co-treated animals. At the molecular level, we found acetylation of the parvovirus nonstructural protein NS1 at residues K85 and K257 to modulate NS1-mediated transcription and cytotoxicity, both of which are enhanced by VPA treatment. These results warrant clinical evaluation of H-1PV/VPA co-treatment against cervical and pancreatic ductal carcinomas.

  4. Temperature dependence of photovoltaic cells, modules, and systems

    SciTech Connect

    Emery, K.; Burdick, J.; Caiyem, Y.

    1996-05-01

    Photovoltaic (PV) cells and modules are often rated in terms of a set of standard reporting conditions defined by a temperature, spectral irradiance, and total irradiance. Because PV devices operates over a wide range of temperatures and irradiances, the temperature and irradiance related behavior must be known. This paper surveys the temperature dependence of crystalline and thin-film, state-of-the-art, research-size cells, modules, and systems measured by a variety of methods. The various error sources and measurement methods that contribute to cause differences in the temperature coefficient for a given cell or module measured with various methods are discussed.

  5. Ultralight amorphous silicon alloy photovoltaic modules for space applications

    NASA Technical Reports Server (NTRS)

    Hanak, J. J.; Chen, Englade; Fulton, C.; Myatt, A.; Woodyard, J. R.

    1987-01-01

    Ultralight and ultrathin, flexible, rollup monolithic PV modules have been developed consisting of multijunction, amorphous silicon alloys for either terrestrial or aerospace applications. The rate of progress in increasing conversion efficiency of stable multijunction and multigap PV cells indicates that arrays of these modules can be available for NASA's high power systems in the 1990's. Because of the extremely light module weight and the highly automated process of manufacture, the monolithic a-Si alloy arrays are expected to be strongly competitive with other systems for use in NASA's space station or in other large aerospace applications.

  6. Temperature dependence of photovoltaic cells, modules, and systems

    SciTech Connect

    Emery, K.; Burdick, J.; Caiyem, Y.

    1996-09-01

    Photovoltaic (PV) cells and modules are often rated in terms of a set of standard reporting conditions defined by a temperature, spectral irradiance, and total irradiance. Because PV devices operate over a wide range of temperatures and irradiances, the temperature and irradiance related behavior must be known. This paper surveys the temperature dependence of crystalline and thin-film, state-of-the-art, research-size cells, modules, and systems measured by a variety of methods. The various error sources and measurement methods that contribute to cause differences in the temperature coefficient for a given cell or module measured with various methods are discussed.

  7. Module Degradation Mechanisms Studied by a Multi-Scale Approach

    SciTech Connect

    Johnston, Steve; Al-Jassim, Mowafak; Hacke, Peter; Harvey, Steven P.; Jiang, Chun-Sheng; Gerber, Andreas; Guthrey, Harvey; Moutinho, Helio; Albin, David; To, Bobby; Tynan, Jerry; Moseley, John; Aguiar, Jeffery; Xiao, Chuanxiao; Waddle, John; Nardone, Marco

    2016-11-21

    A key pathway to meeting the Department of Energy SunShot 2020 goals is to reduce financing costs by improving investor confidence through improved photovoltaic (PV) module reliability. A comprehensive approach to further understand and improve PV reliability includes characterization techniques and modeling from module to atomic scale. Imaging techniques, which include photoluminescence, electroluminescence, and lock-in thermography, are used to locate localized defects responsible for module degradation. Small area samples containing such defects are prepared using coring techniques and are then suitable and available for microscopic study and specific defect modeling and analysis.

  8. AC plasma anemometer—characteristics and design

    NASA Astrophysics Data System (ADS)

    Marshall, Curtis; Matlis, Eric; Corke, Thomas; Gogineni, Sivaram

    2015-08-01

    The characteristics and design of a high-bandwidth flow sensor that uses an AC glow discharge (plasma) as the sensing element is presented. The plasma forms in the air gap between two protruding low profile electrodes attached to a probe body. The output from the anemometer is an amplitude modulated version of the AC voltage input that contains information about the mean and fluctuating velocity components. The anemometer circuitry includes resistance and capacitance elements that simulate a dielectric-barrier to maintain a diffuse plasma, and a constant-current feedback control that maintains operation within the desired glow discharge regime over an extended range of air velocities. Mean velocity calibrations are demonstrated over a range from 0 to 140 m s-1. Over this velocity range, the mean output voltage varied linearly with air velocity, providing a constant static sensitivity. The effect of the electrode gap and input AC carrier frequency on the anemometer static sensitivity and dynamic response are investigated. Experiments are performed to compare measurements obtained with a plasma sensor operating at two AC carrier frequencies against that of a constant-temperature hot-wire. All three sensors were calibrated against the same known velocity reference. An uncertainty based on the standard deviation of the velocity calibration fit was applied to the mean and fluctuating velocity measurements of the three sensors. The motivation is not to replace hot-wires as a general measurement tool, but rather as an alternative to hot-wires in harsh environments or at high Mach numbers where they either have difficulty in surviving or lack the necessary frequency response.

  9. PV Project Finance in the United States, 2016

    SciTech Connect

    Feldman, David; Lowder, Travis; Schwabe, Paul

    2016-09-01

    This brief is a compilation of data points and market insights that reflect the state of the project finance market for solar photovoltaic (PV) assets in the United States as of the third quarter of 2016. This information can generally be used as a simplified benchmark of the costs associated with securing financing for solar PV as well as the cost of the financing itself (i.e., the cost of capital). Three sources of capital are considered -- tax equity, sponsor equity, and debt -- across three segments of the PV marketplace.

  10. Photovoltaic (PV) Impact Assessment for Very High Penetration Levels

    SciTech Connect

    Cheng, Danling; Mather, Barry A.; Seguin, Richard; Hambrick, Joshua; Broadwater, Robert P.

    2016-01-01

    This paper describes a granular approach for investigating the impacts of very high photovoltaic (PV) generation penetration. Studies on two real-world distribution feeders connected to PV plants are presented. The studies include both steady-state and time-series power flow analyses, which include the effects of solar variability. The goal of the study is to predict the effects of increasing levels of PV generation as it reaches very high penetration levels. The loss and return of generation with and without regulation is simulated to capture short-term problems such as voltage fluctuations. Impact results from the analyses are described along with potential mitigations.

  11. CPV Vs. PV from a grid-matching perspective

    NASA Astrophysics Data System (ADS)

    Strobach, E.; Bader, S.; Faiman, D.; Solomon, A. A.; Meron, G.

    2012-10-01

    In a recently-published series of papers we studied the general problem of matching large PV systems of various kinds to the electricity grid. In those studies CPV systems were simulated via an artificial ansatz in which they were treated as 2-axis flat-panel PV systems whose light sensitivity is only to the direct normal component (DNI) of solar irradiance. The present study replaces this ansatz with an experimentally validated model of a real CPV system. We compare a genuine 2-axis high-concentration CPV system with a static flat-panel PV system from the standpoint of matching both system types to the Israeli electricity grid.

  12. PV Validation and Bankability Workshop: San Jose, California

    SciTech Connect

    Granata, J.; Howard, J.

    2011-12-01

    This report is a collaboration between Sandia National Laboratories, the National Renewable Energy Laboratory, and the Florida Solar Energy Center (FSEC). The report provides feedback from the U.S. Department of Energy's (DOE) Solar Program PV Validation and Bankability Workshop in San Jose, California on August 31, 2011. It focuses on the current state of PV in the United States, private funding to fund U.S. PV industry growth, roles and functions of the regional test center program, and ways to improve the current validation and bankability practices.

  13. Strategies for recycling CdTe photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Eberspacher, Chris; Gay, Charles F.; Moskowitz, Paul D.

    1994-12-01

    Recycling end-of-life cadmium telluride (CdTe) photovoltaic (PV) modules may enhance the competitive advantage of CdTe PV in the marketplace, but the experiences of industries with comparable Environmental, Health and Safety (EH&S) challenges suggest that collection and recycling costs can impose significant economic burdens. Customer cooperation and pending changes to US Federal law may improve recycling economics.

  14. Real time live imaging of phytopathogenic bacteria Xanthomonas campestris pv. campestris MAFF106712 in 'plant sweet home'.

    PubMed

    Akimoto-Tomiyama, Chiharu; Furutani, Ayako; Ochiai, Hirokazu

    2014-01-01

    Xanthomonas is one of the most widespread phytobacteria, causing diseases on a variety of agricultural plants. To develop novel control techniques, knowledge of bacterial behavior inside plant cells is essential. Xanthomonas campestris pv. campestris, a vascular pathogen, is the causal agent of black rot on leaves of Brassicaceae, including Arabidopsis thaliana. Among the X. campestris pv. campestris stocks in the MAFF collection, we selected XccMAFF106712 as a model compatible pathogen for the A. thaliana reference ecotype Columbia (Col-0). Using modified green fluorescent protein (AcGFP) as a reporter, we observed real time XccMAFF106712 colonization in planta with confocal microscopy. AcGFP-expressing bacteria colonized the inside of epidermal cells and the apoplast, as well as the xylem vessels of the vasculature. In the case of the type III mutant, bacteria colonization was never detected in the xylem vessel or apoplast, though they freely enter the xylem vessel through the wound. After 9 days post inoculation with XccMAFF106712, the xylem vessel became filled with bacterial aggregates. This suggests that Xcc colonization can be divided into main four steps, (1) movement in the xylem vessel, (2) movement to the next cell, (3) adhesion to the host plant cells, and (4) formation of bacterial aggregates. The type III mutant abolished at least steps (1) and (2). Better understanding of Xcc colonization is essential for development of novel control techniques for black rot.

  15. Module Technology: Current Practice and Issues (Presentation)

    SciTech Connect

    Wohlgemuth, J.

    2010-10-05

    PV modules must provide mechanical support for the cells, protect the world from the voltages inside, protect the cells, diodes and interconnects from the weather outside, couple as much light as possible into the PV cells and minimize the temperature increase of the cells. The package must continue to serve these functions for at least 25 years as that is the typical module warranty period today. Furthermore the package must do all this for as low a cost as possible since the key to large scale PV growth is a reduction in cost while retaining excellent module reliability and durability. This paper will review current module construction practices for both crystalline silicon and thin film PV with emphasis on explaining why the present designs and materials have been selected. Possible long term issues with today's designs and materials will be discussed. Several proposed solutions to these issues will be presented, highlighting the research efforts that will be necessary in order to verify that they can cost effectively solve the identified issues.

  16. Digital ac monitor

    DOEpatents

    Hart, George W.; Kern, Jr., Edward C.

    1987-06-09

    An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer.

  17. Digital ac monitor

    DOEpatents

    Hart, G.W.; Kern, E.C. Jr.

    1987-06-09

    An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer. 24 figs.

  18. Cooling Floor AC Systems

    NASA Astrophysics Data System (ADS)

    Jun, Lu; Hao, Ding; Hong, Zhang; Ce, Gao Dian

    The present HVAC equipments for the residential buildings in the Hot-summer-and-Cold-winter climate region are still at a high energy consuming level. So that the high efficiency HVAC system is an urgently need for achieving the preset government energy saving goal. With its advantage of highly sanitary, highly comfortable and uniform of temperature field, the hot-water resource floor radiation heating system has been widely accepted. This paper has put forward a new way in air-conditioning, which combines the fresh-air supply unit and such floor radiation system for the dehumidification and cooling in summer or heating in winter. By analyze its advantages and limitations, we found that this so called Cooling/ Heating Floor AC System can improve the IAQ of residential building while keep high efficiency quality. We also recommend a methodology for the HVAC system designing, which will ensure the reduction of energy cost of users.

  19. Modeling the irradiance and temperature rependence of photovoltaic modules in PVsyst

    DOE PAGES

    Sauer, Kenneth J.; Roessler, Thomas; Hansen, Clifford W.

    2014-11-10

    In order to reliably simulate the energy yield of photovoltaic (PV) systems, it is necessary to have an accurate model of how the PV modules perform with respect to irradiance and cell temperature. Building on previous work that addresses the irradiance dependence, two approaches to fit the temperature dependence of module power in PVsyst have been developed and are applied here to recent multi-irradiance and -temperature data for a standard Yingli Solar PV module type. The results demonstrate that it is possible to match the measured irradiance and temperature dependence of PV modules in PVsyst. As a result, improvements inmore » energy yield prediction using the optimized models relative to the PVsyst standard model are considered significant for decisions about project financing.« less

  20. Modeling the irradiance and temperature rependence of photovoltaic modules in PVsyst

    SciTech Connect

    Sauer, Kenneth J.; Roessler, Thomas; Hansen, Clifford W.

    2014-11-10

    In order to reliably simulate the energy yield of photovoltaic (PV) systems, it is necessary to have an accurate model of how the PV modules perform with respect to irradiance and cell temperature. Building on previous work that addresses the irradiance dependence, two approaches to fit the temperature dependence of module power in PVsyst have been developed and are applied here to recent multi-irradiance and -temperature data for a standard Yingli Solar PV module type. The results demonstrate that it is possible to match the measured irradiance and temperature dependence of PV modules in PVsyst. As a result, improvements in energy yield prediction using the optimized models relative to the PVsyst standard model are considered significant for decisions about project financing.

  1. Module Two: Voltage; Basic Electricity and Electronics Individualized Learning System.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    In this module the student will study and learn what voltage is, how it is generated, what AC (alternating current) and DC (direct current) are and why both kinds are needed, and how to measure voltages. The module is divided into six lessons: EMF (electromotive force) from chemical action, magnetism, electromagnetic induction, AC voltage, the…

  2. Automated ac galvanomagnetic measurement system

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Espy, P. N.

    1985-01-01

    An automated, ac galvanomagnetic measurement system is described. Hall or van der Pauw measurements in the temperature range 10-300 K can be made at a preselected magnetic field without operator attendance. Procedures to validate sample installation and correct operation of other system functions, such as magnetic field and thermometry, are included. Advantages of ac measurements are discussed.

  3. The ac propulsion system for an electric vehicle, phase 1

    NASA Technical Reports Server (NTRS)

    Geppert, S.

    1981-01-01

    A functional prototype of an electric vehicle ac propulsion system was built consisting of a 18.65 kW rated ac induction traction motor, pulse width modulated (PWM) transistorized inverter, two speed mechanically shifted automatic transmission, and an overall drive/vehicle controller. Design developmental steps, and test results of individual components and the complex system on an instrumented test frame are described. Computer models were developed for the inverter, motor and a representative vehicle. A preliminary reliability model and failure modes effects analysis are given.

  4. Exenatide: AC 2993, AC002993, AC2993A, exendin 4, LY2148568.

    PubMed

    2004-01-01

    Exenatide [AC002993, AC2993A, AC 2993, LY2148568, exendin 4], a glucagon-like peptide-1 (GLP-1) agonist, is a synthetic exendin 4 compound under development with Amylin Pharmaceuticals for the treatment of type 2 diabetes. Both exendin 4 and its analogue, exendin 3, are 39-amino acid peptides isolated from Heloderma horridum lizard venom that have different amino acids at positions 2 and 3, respectively. Exendins are able to stimulate insulin secretion in response to rising blood glucose levels, and modulate gastric emptying to slow the entry of ingested sugars into the bloodstream. Amylin Pharmaceuticals acquired exclusive patent rights for the two exendin compounds (exendin 3 and exendin 4) from the originator, Dr John Eng (Bronx, NY, US). On 20 September 2002, Amylin and Eli Lilly signed a collaborative agreement for the development and commercialisation of exenatide for type 2 diabetes. Under the terms of the agreement, Eli Lilly has paid Amylin a licensing fee of 80 million US dollars and bought Amylin's stock worth 30 million US dollars at 18.69 US dollars a share. After the initial payment, Eli Lilly will pay Amylin up to 85 US dollars million upon reaching certain milestones and also make an additional payment of up to 130 million US dollars upon global commercialisation of exenatide. Both companies will share the US development and commercialisation costs, while Eli Lilly will pick up up to 80% of development costs and all commercialisation costs outside the US. Amylin and Eli Lilly will equally share profit from sales in the US, while Eli Lilly will get 80% of the profit outside the US and Amylin will get the rest. This agreement has also enabled Amylin to train its sales force to co-promote Lilly's human growth hormone Humatrope. Alkermes will receive research and development funding and milestone payments, and also a combination of royalty payments and manufacturing fees based on product sales. Alkermes undertakes the responsibility for the development

  5. Instrumentation for Evaluating PV System Performance Losses from Snow

    SciTech Connect

    Marion, B.; Rodriguez, J.; Pruett, J.

    2009-01-01

    When designing a photovoltaic (PV) system for northern climates, the prospective installation should be evaluated with respect to the potentially detrimental effects of snow preventing solar radiation from reaching the PV cells. The extent to which snow impacts performance is difficult to determine because snow events also increase the uncertainty of the solar radiation measurement, and the presence of snow needs to be distinguished from other events that can affect performance. This paper describes two instruments useful for evaluating PV system performance losses from the presence of snow: (1) a pyranometer with a heater to prevent buildup of ice and snow, and (2) a digital camera for remote retrieval of images to determine the presence of snow on the PV array.

  6. Full Steam Ahead for PV in US Homes?

    SciTech Connect

    Bolinger, Mark A; Barbose, Galen; Wiser, Ryan

    2009-01-15

    In October 2008, the United States Congress extended both the residential and commercial solar investment tax credits (ITCs) for an unprecedented eight years, lifted the $2,000 cap on the residential credit, removed the prohibition on utility use of the commercial credit, and eliminated restrictions on the use of both credits in conjunction with the Alternative Minimum Tax. These significant changes, which apply to systems placed in service on or after January 1, 2009, will increase the value of the solar credits for residential system owners in particular, and are likely--in conjunction with state, local, and utility rebate programs targeting solar--to spur significant growth in residential, commercial, and utility-scale photovoltaic (PV) installations in the years ahead. This article focuses specifically on the residential credit, describing three areas in which removal of the $2,000 cap on the residential ITC will have significant implications for PV rebate program administrators, PV system owners, and the PV industry.

  7. Retaining the Value of PV at High Penetration Workshop

    SciTech Connect

    Kurtz, Sarah; Bolen, Michael

    2016-10-13

    PV prices have dropped and are now attractive without incentives for peaking applications in some locations. Modeling suggests and, empirically, some regions demonstrate that as PV penetration increases its value decreases, predominantly due to a decrease in energy and capacity value. It is not apparent what technologies and price may be needed for PV to supply tens of percent of electricity in the most economically efficient manner. A 1-day workshop was co-sponsored by EPRI and NREL with support from ASU. A dozen presentations and discussions introduced how the interplay of various technologies impact the value of PV, identified technical challenges and gaps impeding implementation, and discussed future R&D needs and opportunities.

  8. The Ramakrishna Mission economic PV development initiative

    SciTech Connect

    Stone, J.L.; Ullal, H.S.; Sherring, C.

    1998-09-01

    India is the world`s second most populous country, quickly approaching one billion persons. Although it has a well-developed electricity grid, many of the people have little or no access to electricity and all of the benefits associated with it. There are areas that are isolated from the grid and will not be connected for many years, if ever. One such area is the Sundarbans located in the delta region of the two great rivers, the Ganges and Brahmaputra, partially in India and partially in Bangladesh. It is estimated that 1.5 million people live in this area, crisscrossed by many islands and rivers, who have only marginal supplies of electricity generated primarily from diesel generators and batteries. Working with the regional non-governmental organization (NGO), the Ramakrishna Mission, and the West Bengal Renewable Energy Development Agency, the governments of India and the US initiated a rural electrification initiative to demonstrate the economic and technical feasibility of photovoltaics to provide limited supplies of electricity for such applications as solar home lighting systems (SHS), water pumping, vaccine refrigeration, communications, and economic development activities. This paper details initial results from approximately 30 kilowatts of PV systems installed in the area, including socio-economic impacts and technical performance.

  9. Microgrid-Ready Solar PV; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    2015-07-01

    Designing new solar projects to be 'microgrid-ready' enables the U.S. DoD, other federal agencies, and the private sector to plan future microgrid initiatives to utilize solar PV as a generating resource. This fact sheet provides background information with suggested language for several up-front considerations that can be added to a solar project procurement or request for proposal (RFP) that will help ensure that PV systems are built for future microgrid connection.

  10. pV3-Gold Visualization Environment for Computer Simulations

    NASA Technical Reports Server (NTRS)

    Babrauckas, Theresa L.

    1997-01-01

    A new visualization environment, pV3-Gold, can be used during and after a computer simulation to extract and visualize the physical features in the results. This environment, which is an extension of the pV3 visualization environment developed at the Massachusetts Institute of Technology with guidance and support by researchers at the NASA Lewis Research Center, features many tools that allow users to display data in various ways.

  11. Draft genome sequences of three Xanthomonas translucens pathovar reference strains (pv. arrhenatheri, pv. poae and pv. phlei) with different specificities for forage grasses.

    PubMed

    Hersemann, Lena; Wibberg, Daniel; Widmer, Franco; Vorhölter, Frank-Jörg; Kölliker, Roland

    2016-01-01

    As causal agents of bacterial wilt in pastures and meadows, bacteria of the species Xanthomonas translucens are a serious issue in forage grass production. So far, only little is known about host-pathogen interactions at the molecular level and the lack of comprehensive genome data impeded targeted breeding strategies towards resistant forage grass cultivars. Here we announce the draft genome sequences of three grass-pathogenic Xanthomonas translucens pathotype strains, i.e. pv. arrhenatheri LMG 727, pv. poae LMG 728 and pv. phlei LMG 730 isolated from Arrhenatherum elatius (L.) P. Beauv. ex J. Presl & C. Presl (Switzerland), Poa trivialis L. (Switzerland) and Phleum pratense L. (Norway), respectively. The genomes of all three strains revealed a non-canonical type III secretion system and a set of 22 type III effectors as common virulence-related traits. Distinct inter-pathovar differences were observed for the lipopolysaccharide biosynthesis gene cluster and the presence of nonribosomal peptide synthetases.

  12. Residential Solar PV Systems in the Carolinas: Opportunities and Outcomes.

    PubMed

    Alqahtani, Bandar Jubran; Holt, Kyra Moore; Patiño-Echeverri, Dalia; Pratson, Lincoln

    2016-02-16

    This paper presents a first-order analysis of the feasibility and technical, environmental, and economic effects of large levels of solar photovoltaic (PV) penetration within the services areas of the Duke Energy Carolinas (DEC) and Duke Energy Progress (DEP). A PV production model based on household density and a gridded hourly global horizontal irradiance data set simulates hourly PV power output from roof-top installations, while a unit commitment and real-time economic dispatch (UC-ED) model simulates hourly system operations. We find that the large generating capacity of base-load nuclear power plants (NPPs) without ramping capability in the region limits PV integration levels to 5.3% (6510 MW) of 2015 generation. Enabling ramping capability for NPPs would raise the limit of PV penetration to near 9% of electricity generated. If the planned retirement of coal-fired power plants together with new installations and upgrades of natural gas and nuclear plants materialize in 2025, and if NPPs operate flexibly, then the share of coal-fired electricity will be reduced from 37% to 22%. A 9% penetration of electricity from PV would further reduce the share of coal-fired electricity by 4-6% resulting in a system-wide CO2 emissions rate of 0.33 to 0.40 tons/MWh and associated abatement costs of 225-415 (2015$ per ton).

  13. High Penetration PV Deployment in the Arizona Public Service System

    SciTech Connect

    Narang, D.; Hambrick, J.

    2011-01-01

    In an effort to better understand the impacts of high penetrations of photovoltaic (PV) generators on distribution systems, Arizona Public Service (APS) and its partners have begun work on a multi-year project to develop the tools and knowledgebase needed to safely and reliably integrate high penetrations of utility and residential scale PV. Building upon the APS Community Power Project - Flagstaff Pilot, this project will analyze the impact of PV on a representative feeder in northeast Flagstaff. To quantify and catalog the effects of the estimated 1.5 MW of PV that will be installed on the feeder (both smaller units at homes as well as large, centrally located systems), high-speed weather and electrical data acquisition systems and digital 'smart' meters are being designed and installed to facilitate monitoring and to build and validate comprehensive, high-resolution models of the distribution system. These models will be used to analyze the impacts of the PV on distribution circuit protection systems (including anti-islanding), predict voltage regulation and phase balance issues, and develop volt/var control schemes. The goal of this paper is to provide insight and lessons learned on the early stages of high penetration PV deployment. Primarily focusing on modeling and data acquisition, this paper describes the overall project, early results, and plans for future phases of the project.

  14. Integrating High Penetrations of PV into Southern California

    SciTech Connect

    Kroposki, B.; Mather, B.; Hasper-Tuttle, J.; Neal, R.; Katiraei, F.; Yazdani, A.; Aguero, J. R.; Hoff, T. E.; Norris, B. L.; Parkins, A.; Seguin, R.; Schauder, C.

    2011-01-01

    California regulators recently approved a plan proposed by Southern California Edison (SCE) to install 500 MW of distributed photovoltaic (PV) energy in its utility service territory over the next 5 years. The installations will include 250 MW of utility-owned solar and 250 MW of independently owned solar. SCE expects that the majority of these systems will be commercial-scale rooftop PV systems connected at various points in the distribution system. Each of the SCE rooftop PV systems will typically have a rating of 1-3 MW. To understand the impact of high-penetration PV on the distribution grid, the National Renewable Energy Laboratory (NREL) and SCE brought together a team of experts in resource assessment, distribution modeling, and planning to help analyze the impacts of adding high penetration of PV into the distribution system. Through modeling and simulation, laboratory testing, and field demonstrations, the team will address the issues identified in the analysis by fully examining the challenges, developing solutions, and transitioning those solutions to the field for large-scale deployment. This paper gives an update on the project and discusses technical results of integrating a large number of distributed PV systems into the grid.

  15. Continuing Developments in PV Risk Management: Strategies, Solutions, and Implications

    SciTech Connect

    Lowder, T.; Mendelsohn, M.; Speer, B.; Hill, R.

    2013-02-01

    As the PV industry matures, successful risk management practices will become more imperative to ensure investor confidence, control costs, and facilitate further growth. This report discusses several key aspects of risk management during the commercial- and utility-scale project life cycle, from identification of risks, to the process of mitigating and allocating those risks among project parties, to transferring those risks through insurance. The report also explores novel techniques in PV risk management, options to offload risks onto the capital markets, and innovative insurance policies (namely warranty policies) that address risks unique to the PV sector. One of the major justifications for robust risk management in the PV industry is the cost-reduction opportunities it affords. If the PV industry can demonstrate the capability to successfully manage its risks, thereby inspiring confidence in financiers, it may be able to obtain a lower cost of capital in future transactions. A lower cost of capital translates to a lower cost of energy, which will in turn enhance PV?s competitiveness at a time when it will have to rely less on subsidies to support its market penetration.

  16. Review of PV Inverter Technology Cost and Performance Projections

    SciTech Connect

    Navigant Consulting Inc.

    2006-01-01

    The National Renewable Energy Laboratory (NREL) has a major responsibility in the implementation of the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program. Sandia National Laboratories (SNL) has a major role in supporting inverter development, characterization, standards, certifications, and verifications. The Solar Energy Technologies Program recently published a Multiyear Technical Plan, which establishes a goal of reducing the Levelized Energy Cost (LEC) for photovoltaic (PV) systems to $0.06/kWh by 2020. The Multiyear Technical Plan estimates that, in order to meet the PV system goal, PV inverter prices will need to decline to $0.25-0.30 Wp by 2020. DOE determined the need to conduct a rigorous review of the PV Program's technical and economic targets, including the target set for PV inverters. NREL requested that Navigant Consulting Inc.(NCI) conduct a review of historical and projected cost and performance improvements for PV inverters, including identification of critical barriers identified and the approaches government might use to address them.

  17. Control Strategies for the DAB Based PV Interface System.

    PubMed

    El-Helw, Hadi M; Al-Hasheem, Mohamed; Marei, Mostafa I

    2016-01-01

    This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system.

  18. Control Strategies for the DAB Based PV Interface System

    PubMed Central

    El-Helw, Hadi M.; Al-Hasheem, Mohamed; Marei, Mostafa I.

    2016-01-01

    This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system. PMID:27560138

  19. Performance evaluation of stand alone hybrid PV-wind generator

    SciTech Connect

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H.; Yahaya, M. S.

    2015-05-15

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  20. Performance evaluation of stand alone hybrid PV-wind generator

    NASA Astrophysics Data System (ADS)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H.; Yahaya, M. S.

    2015-05-01

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  1. A review of manufacturing metrology for improved reliability of silicon photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Davis, Kristopher O.; Walters, Joseph; Schneller, Eric; Seigneur, Hubert; Brooker, R. Paul; Scardera, Giuseppe; Rodgers, Marianne P.; Mohajeri, Nahid; Shiradkar, Narendra; Dhere, Neelkanth G.; Wohlgemuth, John; Rudack, Andrew C.; Schoenfeld, Winston V.

    2014-10-01

    In this work, the use of manufacturing metrology across the supply chain to improve crystalline silicon (c-Si) photovoltaic (PV) module reliability and durability is addressed. Additionally, an overview and summary of a recent extensive literature survey of relevant measurement techniques aimed at reducing or eliminating the probability of field failures is presented. An assessment of potential gaps is also given, wherein the PV community could benefit from new research and demonstration efforts. This review is divided into three primary areas representing different parts of the c-Si PV supply chain: (1) feedstock production, crystallization and wafering; (2) cell manufacturing; and (3) module manufacturing.

  2. Degradation in PV Encapsulant Strength of Attachment: An Interlaboratory Study Towards a Climate-Specific Test: Preprint

    SciTech Connect

    Miller, David C.; Annigoni, Eleonora; Ballion, Amal; Bokria, Jayesh G.; Bruckman, Laura S.; Burns, David M.; Chen, Xinxin; Feng, Jiangtao; French, Roger H.; Fowler, Sean; Honeker, Christian C.; Kempe, Michael D.; Khonkar, Hussam; Kohl, Michael; Perret-Aebi, Laure-Emmanuelle; Phillips, Nancy H.; Scott, Kurt P.; Sculati-Meillaud, Fanny; Wohlgemuth, John H.

    2016-07-01

    Reduced strength of attachment of the encapsulant resulting from outdoor environment, including ultraviolet (UV) radiation, may decrease photovoltaic (PV) module lifetime by enabling widespread corrosion of internal components. To date, few studies exist showing how the adhesion of PV components varies with environmental stress. We have conducted an interlaboratory experiment to provide an understanding that will be used to develop climatic specific module tests. Factors examined in the study included the UV light source (lamp type), temperature, and humidity to be proposed for use in accelerated aging tests. A poly (ethylene-co-vinyl acetate) (EVA) formulation often used in veteran PV installations was studied using a compressive shear test - to quantify the strength of attachment at the EVA/glass interface. Replicate laminated glass/polymer/glass coupon specimens were weathered at 12 institutions using a variety of indoor chambers or field aging. Shear strength, shear strain, and toughness were measured using a mechanical load-frame for the compressive shear test, with subsequent optical imaging and electron microscopy of the separated surfaces.

  3. Performance of solmacs, a high PV solar concentrator with efficient optics

    NASA Astrophysics Data System (ADS)

    Thibert, T.; Hellin, M.-L.; Loicq, J.; Mazy, E.; Jacques, L.; Verstraeten, D.; Gillis, J.-M.; Languy, F.; Emmerechts, C.; Beeckman, E.; Habraken, S.; Lecat, J.-H.

    2012-10-01

    A new solar panel with high concentration photovoltaic technology (x700) has been designed, prototyped and tested in the SOLMACS project. The quality of concentrating optics is a key factor for high module efficiency. Therefore new dedicated PMMA Fresnel lenses were studied and produced by injection molding. Lens design, material and production process were optimized to achieve a high optical yield of 86%. Thorough lens performance assessment in optical laboratory was completed with lifetime UV aging tests. Another important aspect is the thermal control of the hot spot created under the solar cell that receives the concentrated flux of 700 Suns. A dedicated heat spreader was developed to achieve passive thermal control with minimum mass and cost. This was supported by thermal models and tests at both cell and module level. 35% triple junction cells were implemented in the module. Micro-assembly technologies were used for the cell packaging and electrical connections. In support to the research, a continuous solar simulator was designed and built to assess the system performance, both at component and module level. The concentrator developments were integrated in a prototype and tested both indoor with the simulator and outdoor on the CSL solar test platform. The overall efficiency of the PV concentrator module is 28.5%.

  4. Proposal of Xanthomonas translucens pv. pistaciae pv. nov., pathogenic to pistachio (Pistacia vera).

    PubMed

    Giblot-Ducray, Danièle; Marefat, Alireza; Gillings, Michael R; Parkinson, Neil M; Bowman, John P; Ophel-Keller, Kathy; Taylor, Cathy; Facelli, Evelina; Scott, Eileen S

    2009-12-01

    Strains of Xanthomonas translucens have caused dieback in the Australian pistachio industry for the last 15 years. Such pathogenicity to a dicotyledonous woody host contrasts with that of other pathovars of X. translucens, which are characterized by their pathogenicity to monocotyledonous plant families. Further investigations, using DNA-DNA hybridization, gyrB gene sequencing and integron screening, were conducted to confirm the taxonomic status of the X. translucens pathogenic to pistachio. DNA-DNA hybridization provided a clear classification, at the species level, of the pistachio pathogen as a X. translucens. In the gyrB-based phylogeny, strains of the pistachio pathogen clustered among the X. translucens pathovars as two distinct lineages. Integron screening revealed that the cassette arrays of strains of the pistachio pathogen were different from those of other Xanthomonas species, and again distinguished two groups. Together with previously reported pathogenicity data, these results confirm that the pistachio pathogen is a new pathovar of X. translucens and allow hypotheses about its origin. The proposed name is Xanthomonas translucens pv. pistaciae pv. nov.

  5. Layoff Handling Still Lags ACS Standards.

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1981

    1981-01-01

    Reviews termination procedures of professional chemists and the compliance of these terminations to the American Chemical Society's (ACS's) Professional Employment Guidelines. Provides the ACS guidelines. (DS)

  6. AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT XVII, LEARNING ABOUT AC GENERATOR (ALTERNATOR) PRINCIPLES (PART II).

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

    THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATING PRINCIPLES AND THE SERVICING AND TESTING PROCEDURES FOR ALTERNATING CURRENT (AC) GENERATORS AND REGULATORS USED ON DIESEL POWERED EQUIPMENT. TOPICS ARE REVIEW OF ALTERNATOR PRINCIPLES, ALTERNATOR SERVICING AND TESTING, ALTERNATOR REGULATOR OPERATING…

  7. Bcl-2△21 and Ac-DEVD-CHO Inhibit Death of Wheat Microspores

    PubMed Central

    Sinha, Rakesh K.; Pospíšil, Pavel; Maheshwari, Priti; Eudes, François

    2016-01-01

    Microspore cell death and low green plant production efficiency are an integral obstacle in the development of doubled haploid production in wheat. The aim of the current study was to determine the effect of anti-apoptotic recombinant human B-cell lymphoma-2 (Bcl-2△21) and caspase-3-inhibitor (Ac-DEVD-CHO) in microspore cell death in bread wheat cultivars AC Fielder and AC Andrew. Induction medium containing Bcl-2△21 and Ac-DEVD-CHO yielded a significantly higher number of viable microspores, embryo-like structures and total green plants in wheat cultivars AC Fielder and AC Andrew. Total peroxidase activity was lower in Bcl-2△21 treated microspore cultures at 96 h of treatment compared to control and Ac-DEVD-CHO. Electron paramagnetic resonance study of total microspore protein showed a different scavenging activity for Bcl-2△21 and Ac-DEVD-CHO. Bcl-2△21 scavenged approximately 50% hydroxyl radical (HO•) formed, whereas Ac-DEVD-CHO scavenged approximately 20% of HO•. Conversely, reduced caspase-3-like activities were detected in the presence of Bcl-2△21 and Ac-DEVD-CHO, supporting the involvement of Bcl-2△21 and Ac-DEVD-CHO in increasing microspore viability by reducing oxidative stress and caspase-3-like activity. Our results indicate that Bcl-2△21 and Ac-DEVD-CHO protects cells from cell death following different pathways. Bcl-2△21 prevents cell damage by detoxifying HO• and suppressing caspase-3-like activity, while Ac-DEVD-CHO inhibits the cell death pathways by modulating caspase-like activity. PMID:28082995

  8. Bcl-2△21 and Ac-DEVD-CHO Inhibit Death of Wheat Microspores.

    PubMed

    Sinha, Rakesh K; Pospíšil, Pavel; Maheshwari, Priti; Eudes, François

    2016-01-01

    Microspore cell death and low green plant production efficiency are an integral obstacle in the development of doubled haploid production in wheat. The aim of the current study was to determine the effect of anti-apoptotic recombinant human B-cell lymphoma-2 (Bcl-2△21) and caspase-3-inhibitor (Ac-DEVD-CHO) in microspore cell death in bread wheat cultivars AC Fielder and AC Andrew. Induction medium containing Bcl-2△21 and Ac-DEVD-CHO yielded a significantly higher number of viable microspores, embryo-like structures and total green plants in wheat cultivars AC Fielder and AC Andrew. Total peroxidase activity was lower in Bcl-2△21 treated microspore cultures at 96 h of treatment compared to control and Ac-DEVD-CHO. Electron paramagnetic resonance study of total microspore protein showed a different scavenging activity for Bcl-2△21 and Ac-DEVD-CHO. Bcl-2△21 scavenged approximately 50% hydroxyl radical (HO(•)) formed, whereas Ac-DEVD-CHO scavenged approximately 20% of HO(•). Conversely, reduced caspase-3-like activities were detected in the presence of Bcl-2△21 and Ac-DEVD-CHO, supporting the involvement of Bcl-2△21 and Ac-DEVD-CHO in increasing microspore viability by reducing oxidative stress and caspase-3-like activity. Our results indicate that Bcl-2△21 and Ac-DEVD-CHO protects cells from cell death following different pathways. Bcl-2△21 prevents cell damage by detoxifying HO(•) and suppressing caspase-3-like activity, while Ac-DEVD-CHO inhibits the cell death pathways by modulating caspase-like activity.

  9. Photovoltaic Modules: Effect of Tilt Angle on Soiling

    NASA Astrophysics Data System (ADS)

    Cano, Jose

    2011-12-01

    Photovoltaic (PV) systems are one of the next generation's renewable energy sources for our world energy demand. PV modules are highly reliable. However, in polluted environments, over time, they will collect grime and dust. There are also limited field data studies about soiling losses on PV modules. The study showed how important it is to investigate the effect of tilt angle on soiling. The study includes two sets of mini-modules. Each set has 9 PV modules tilted at 0, 5, 10, 15, 20, 23, 30, 33 and 40°. The first set called "Cleaned" was cleaned every other day. The second set called "Soiled" was never cleaned after the first day. The short circuit current, a measure of irradiance, and module temperature was monitored and recorded every two minutes over three months (January-March 2011). The data were analyzed to investigate the effect of tilt angle on daily and monthly soiling, and hence transmitted solar insolation and energy production by PV modules. The study shows that during the period of January through March 2011 there was an average loss due to soiling of approximately 2.02% for 0° tilt angle. Modules at tilt angles 23° and 33° also have some insolation losses but do not come close to the module at 0° tilt angle. Tilt angle 23° has approximately 1.05% monthly insolation loss, and 33° tilt angle has an insolation loss of approximately 0.96%. The soiling effect is present at any tilt angle, but the magnitude is evident: the flatter the solar module is placed the more energy it will lose.

  10. A system for tranmitting low frequency analog signals over ac power lines

    DOEpatents

    Baker, S.P.; Durall, R.L.; Haynes, H.D.

    1987-07-30

    A system for transmitting low frequency analog signals over ac power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an ac power line. The modulation signal frequency range is selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the ac power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal. 4 figs.

  11. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-01-01

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  12. System for transmitting low frequency analog signals over AC power lines

    DOEpatents

    Baker, Steven P.; Durall, Robert L.; Haynes, Howard D.

    1989-09-05

    A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

  13. Comparative Analysis and Considerations for PV Interconnection Standards in the United States and China

    SciTech Connect

    Gao, David Wenzhong; Muljadi, Eduard; Tian, Tian; Miller, Mackay

    2017-01-01

    The main objectives of this report are to evaluate China's photovoltaic (PV) interconnection standards and the U.S. counterparts and to propose recommendations for future revisions to these standards. This report references the 2013 report Comparative Study of Standards for Grid-Connected PV System in China, the U.S. and European Countries, which compares U.S., European, and China's PV grid interconnection standards; reviews various metrics for the characterization of distribution network with PV; and suggests modifications to China's PV interconnection standards and requirements. The recommendations are accompanied by assessments of four high-penetration PV grid interconnection cases in the United States to illustrate solutions implemented to resolve issues encountered at different sites. PV penetration in China and in the United States has significantly increased during the past several years, presenting comparable challenges depending on the conditions of the grid at the point of interconnection; solutions are generally unique to each interconnected PV installation or PV plant.

  14. Singing modulates parvalbumin interneurons throughout songbird forebrain vocal control circuitry

    PubMed Central

    Zengin-Toktas, Yildiz

    2017-01-01

    Across species, the performance of vocal signals can be modulated by the social environment. Zebra finches, for example, adjust their song performance when singing to females (‘female-directed’ or FD song) compared to when singing in isolation (‘undirected’ or UD song). These changes are salient, as females prefer the FD song over the UD song. Despite the importance of these performance changes, the neural mechanisms underlying this social modulation remain poorly understood. Previous work in finches has established that expression of the immediate early gene EGR1 is increased during singing and modulated by social context within the vocal control circuitry. Here, we examined whether particular neural subpopulations within those vocal control regions exhibit similar modulations of EGR1 expression. We compared EGR1 expression in neurons expressing parvalbumin (PV), a calcium buffer that modulates network plasticity and homeostasis, among males that performed FD song, males that produced UD song, or males that did not sing. We found that, overall, singing but not social context significantly affected EGR1 expression in PV neurons throughout the vocal control nuclei. We observed differences in EGR1 expression between two classes of PV interneurons in the basal ganglia nucleus Area X. Additionally, we found that singing altered the amount of PV expression in neurons in HVC and Area X and that distinct PV interneuron types in Area X exhibited different patterns of modulation by singing. These data indicate that throughout the vocal control circuitry the singing-related regulation of EGR1 expression in PV neurons may be less influenced by social context than in other neuron types and raise the possibility of cell-type specific differences in plasticity and calcium buffering. PMID:28235074

  15. AC propulsion system for an electric vehicle, phase 2

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1983-01-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  16. Thermal performances of vertical hybrid PV/T air collector

    NASA Astrophysics Data System (ADS)

    Tabet, I.; Touafek, K.; Bellel, N.; Khelifa, A.

    2016-11-01

    In this work, numerical analyses and the experimental validation of the thermal behavior of a vertical photovoltaic thermal air collector are investigated. The thermal model is developed using the energy balance equations of the PV/T air collector. Experimental tests are conducted to validate our mathematical model. The tests are performed in the southern Algerian region (Ghardaïa) under clear sky conditions. The prototype of the PV/T air collector is vertically erected and south oriented. The absorber upper plate temperature, glass cover temperature, air temperature in the inlet and outlet of the collector, ambient temperature, wind speed, and solar radiation are measured. The efficiency of the collector increases with increase in mass flow of air, but the increase in mass flow of air reduces the temperature of the system. The increase in efficiency of the PV/T air collector is due to the increase in the number of fins added. In the experiments, the air temperature difference between the inlet and the outlet of the PV/T air collector reaches 10 ° C on November 21, 2014, the interval time is between 10:00 and 14:00, and the temperature of the upper plate reaches 45 ° C at noon. The mathematical model describing the dynamic behavior of the typical PV/T air collector is evaluated by calculating the root mean square error and mean absolute percentage error. A good agreement between the experiment and the simulation results is obtained.

  17. Economic analysis of PV hybrid power system: Pinnacles National Monument

    SciTech Connect

    Rosenthal, A.; Durand, S.; Thomas, M.; Post, H.

    1997-11-01

    PV hybrid electric power systems can offer an economically competitive alternative to engine generator (genset) systems in many off-grid applications. Besides the obvious `green` advantages of producing less noise and emissions, the PV hybrid can, in some cases, offer a lower life-cycle cost (LCC) then the genset. This paper evaluates the LCC of the 9.6 kWp PV hybrid power system installed by the National Park Services (NPS) at Pinnacles National Monument, CA. NPS motivation for installation of this hybrid was not based on economics, but rather the need to replace two aging diesel gensets with an alternative that would be quieter, fuel efficient, and more in keeping with new NPS emphasis on sustainable design and operations. In fact, economic analysis shows a lower 20-year LCC for the installed PV hybrid than for simple replacement of the two gensets. The analysis projects are net savings by the PV hybrid system of $83,561 and over 162,000 gallons of propane when compared with the genset-only system. This net savings is independent of the costs associated with environmental emissions. The effects of including emissions costs, according to NPS guidelines, is also discussed. 5 refs., 2 figs., 3 tabs.

  18. Geographic smoothing of solar PV: results from Gujarat

    NASA Astrophysics Data System (ADS)

    Klima, Kelly; Apt, Jay

    2015-10-01

    We examine the potential for geographic smoothing of solar photovoltaic (PV) electricity generation using 13 months of observed power production from utility-scale plants in Gujarat, India. To our knowledge, this is the first published analysis of geographic smoothing of solar PV using actual generation data at high time resolution from utility-scale solar PV plants. We use geographic correlation and Fourier transform estimates of the power spectral density (PSD) to characterize the observed variability of operating solar PV plants as a function of time scale. Most plants show a spectrum that is linear in the log-log domain at high frequencies f, ranging from {f}-1.23 to {f}-1.56 (slopes of -1.23 and -1.56), thus exhibiting more relative variability at high frequencies than exhibited by wind plants. PSDs for large PV plants have a steeper slope than those for small plants, hence more smoothing at short time scales. Interconnecting 20 Gujarat plants yields a {f}-1.66 spectrum, reducing fluctuations at frequencies corresponding to 6 h and 1 h by 23% and 45%, respectively. Half of this smoothing can be obtained through connecting 4-5 plants; reaching marginal improvement of 1% per added plant occurs at 12-14 plants. The largest plant (322 MW) showed an {f}-1.76 spectrum. This suggests that in Gujarat the potential for smoothing is limited to that obtained by one large plant.

  19. Geographic smoothing of solar PV: Results from Gujarat

    DOE PAGES

    Klima, Kelly; Apt, Jay

    2015-09-24

    We examine the potential for geographic smoothing of solar photovoltaic (PV) electricity generation using 13 months of observed power production from utility-scale plants in Gujarat, India. To our knowledge, this is the first published analysis of geographic smoothing of solar PV using actual generation data at high time resolution from utility-scale solar PV plants. We use geographic correlation and Fourier transform estimates of the power spectral density (PSD) to characterize the observed variability of operating solar PV plants as a function of time scale. Most plants show a spectrum that is linear in the log–log domain at high frequencies f,more » ranging from f-1.23 to f-1.56 (slopes of -1.23 and -1.56), thus exhibiting more relative variability at high frequencies than exhibited by wind plants. PSDs for large PV plants have a steeper slope than those for small plants, hence more smoothing at short time scales. Interconnecting 20 Gujarat plants yields a f-1.66 spectrum, reducing fluctuations at frequencies corresponding to 6 h and 1 h by 23% and 45%, respectively. Half of this smoothing can be obtained through connecting 4-5 plants; reaching marginal improvement of 1% per added plant occurs at 12-14 plants. The largest plant (322 MW) showed an f-1.76 spectrum. Furthermore, this suggests that in Gujarat the potential for smoothing is limited to that obtained by one large plant.« less

  20. High Throughput, Continuous, Mass Production of Photovoltaic Modules

    SciTech Connect

    Kurt Barth

    2008-02-06

    AVA Solar has developed a very low cost solar photovoltaic (PV) manufacturing process and has demonstrated the significant economic and commercial potential of this technology. This I & I Category 3 project provided significant assistance toward accomplishing these milestones. The original goals of this project were to design, construct and test a production prototype system, fabricate PV modules and test the module performance. The original module manufacturing costs in the proposal were estimated at $2/Watt. The objectives of this project have been exceeded. An advanced processing line was designed, fabricated and installed. Using this automated, high throughput system, high efficiency devices and fully encapsulated modules were manufactured. AVA Solar has obtained 2 rounds of private equity funding, expand to 50 people and initiated the development of a large scale factory for 100+ megawatts of annual production. Modules will be manufactured at an industry leading cost which will enable AVA Solar's modules to produce power that is cost-competitive with traditional energy resources. With low manufacturing costs and the ability to scale manufacturing, AVA Solar has been contacted by some of the largest customers in the PV industry to negotiate long-term supply contracts. The current market for PV has continued to grow at 40%+ per year for nearly a decade and is projected to reach $40-$60 Billion by 2012. Currently, a crystalline silicon raw material supply shortage is limiting growth and raising costs. Our process does not use silicon, eliminating these limitations.

  1. Modular AC Nano-Grid with Four-Quadrant Micro-Inverters and High-Efficiency DC-DC Conversion

    NASA Astrophysics Data System (ADS)

    Poshtkouhi, Shahab

    A significant portion of the population in developing countries live in remote communities, where the power infrastructure and the required capital investment to set up local grids do not exist. This is due to the fuel shipment and utilization costs required for fossil fuel based generators, which are traditionally used in these local grids, as well as high upfront costs associated with the centralized Energy Storage Systems (ESS). This dissertation targets modular AC nano-grids for these remote communities developed at minimal capital cost, where the generators are replaced with multiple inverters, connected to either Photovoltaic (PV) or battery modules, which can be gradually added to the nano-grid. A distributed droop-based control architecture is presented for the PV and battery Micro-Inverters (MIV) in order to achieve frequency and voltage stability, as well as active and reactive power sharing. The nano-grid voltage is regulated collectively in either one of four operational regions. Effective load sharing and transient handling are demonstrated experimentally by forming a nano-grid which consists of two custom 500 W MIVs. The MIVs forming the nano-grid have to meet certain requirements. A two-stage MIV architecture and control scheme with four-quadrant power-flow between the nano-grid, the PV/battery and optional short-term storage is presented. The short-term storage is realized using high energy-density Lithium-Ion Capacitor (LIC) technology. A real-time power smoothing algorithm utilizing LIC modules is developed and tested, while the performance of the 100 W MIV is experimentally verified under closed-loop dynamic conditions. Two main limitations of the DAB topology, as the core of the MIV architecture's dc-dc stage, are addressed: 1) This topology demonstrates poor efficiency and limited regulation accuracy at low power. These are improved by introducing a modified topology to operate the DAB in Flyback mode, achieving up to an 8% increase in

  2. PV Cz silicon manufacturing technology improvements

    NASA Astrophysics Data System (ADS)

    Jester, T.

    1995-09-01

    This describes work done in the final phase of a 3-y, 3-phase contract to demonstrate cost reductions and improvements in manufacturing technology. The work focused on near-term projects in the SSI (Siemens Solar Industries) Czochralski (Cz) manufacturing facility in Camarillo, CA; the final phase was concentrated in areas of crystal growth, wafer technology, and environmental, safety, and health issues. During this period: (1) The crystal-growing operation improved with increased growth capacity; (2) Wafer processing with wire saws continued to progress; the wire saws yielded almost 50 percent more wafers per inch in production. The wire saws needs less etching, too; (3) Cell processing improvements focused on better handling and higher mechanical yield. The cell electrical distribution improved with a smaller standard deviation in the distribution; and (4) Module designs for lower material and labor costs continued, with focus on a new junction box, larger modules with larger cells, and less costly framing techniques. Two modules demonstrating these cost reductions were delivered during this phase.

  3. AcMNPV-mediated expression of BmK IT promotes the apoptosis of Sf9 cells and replication of AcMNPV.

    PubMed

    Fu, Yue-Jun; Zhao, Jie; Liang, Ai-Hua; Hu, Feng-Yun

    2015-06-25

    Chinese scorpion Buthus martensii Karsch (BmK) venom is a rich source of neurotoxins which bind to various ion channels with high affinity and specificity and thus widely used as compounds to modulate channel gating or channel currents. To promote the insecticidal effects of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), the gene encoding an excitatory insect toxin, BmK IT, was inserted into the genome of AcMNPV to construct a recombinant baculovirus, AcMNPV-BmK IT. Spodopter frugiperda 9 (Sf9) cells were infected with AcMNPV and AcMNPV-BmK IT respectively for 24 h. Results from the MTT assay, TUNEL assay, analysis of the expression level of apoptosis-related proteins (c-Myc, cleaved-Caspase3, Bcl-2 and Bax) of Sf9 cells, the transcription level of key genes (38K, C42, P78, F) of AcMNPV, and viral propagation assay demonstrated that AcMNPV-mediated expression of BmK IT promoted the apoptosis of Sf9 cells and replication of AcMNPV. The results laid a foundation for further structural and functional analysis of BmK IT.

  4. Non-contact measurement of electric potential of photovoltaic cells in a module and novel characterization technologies

    NASA Astrophysics Data System (ADS)

    Hishikawa, Yoshihiro; Yamagoe, Kengo; Onuma, Tsuyoshi

    2015-08-01

    A novel noncontact method of measuring the electric potential of component cells in photovoltaic (PV) modules is investigated using electrostatic field measurement technology. Experimental results for various kinds of PV cells and modules are presented, and their measurement principle as well as practical factors that affect the measurement results are discussed. It is demonstrated that the DC electric potential of the cells in various crystalline silicon and thin-film PV modules can be measured indoors through their cover glass or backsheet within a resolution of the output voltage of about 1 cell. The method is also applicable to the outdoor measurement of PV modules under grid-connected operation, and enables various kinds of characterization such as identifying low-performance cells in a PV module and degraded modules in a PV array, and determining the balance of their output current under outdoor operating conditions. Different distributions of electric potential measured from the front and back surfaces are observed for some types of modules. These differences are suggested, by the results of the analysis of experiments and numerical simulations, to originate from the modification of the module’s surface electric potential by slight current flow through its component materials such as the cover glass, ethylene vinyl acetate (EVA), and backsheet.

  5. Design and Test of a Continuous Duty Pulsed AC Generator

    DTIC Science & Technology

    1991-06-01

    DESIGN AND TEST OF A CONTINUOUS DUTY PULSED AC GENERATOR* R. M. Calfo, D. J . Scott , and D. W. Scherbarth Westinghouse Electric Corporation...Proceedings of the 19th Power Modulator Symposium, June 26-28, 1990, San Diego, CA. Dennis J . Scott and Raymond M. Calfo, •Synchronous Machines for...Pulsed Power Applications,• Seventh IEEE Pulsed Power Conference, June 11-14, 1989, Monterey, CA. D. J . Scott , R. M. Calfo, H. R. Schwenk

  6. Design and simulation of maximum power point tracking (MPPT) system on solar module system using constant voltage (CV) method

    NASA Astrophysics Data System (ADS)

    Bhatara, Sevty Satria; Iskandar, Reza Fauzi; Kirom, M. Ramdlan

    2016-02-01

    Solar energy is one of renewable energy resource where needs a photovoltaic module to convert it into electrical energy. One of the problems on solar energy conversion is the process of battery charging. To improve efficiency of energy conversion, PV system needs another control method on battery charging called maximum power point tracking (MPPT). This paper report the study on charging optimation using constant voltage (CV) method. This method has a function of determining output voltage of the PV system on maximal condition, so PV system will always produce a maximal energy. A model represented a PV system with and without MPPT was developed using Simulink. PV system simulation showed a different outcome energy when different solar radiation and numbers of solar module were applied in the model. On the simulation of solar radiation 1000 W/m2, PV system with MPPT produces 252.66 Watt energy and PV system without MPPT produces 252.66 Watt energy. The larger the solar radiation, the greater the energy of PV modules was produced.

  7. In-Situ Characterization of Potential-Induced Degradation in Crystalline Silicon Photovoltaic Modules Through Dark I–V Measurements

    SciTech Connect

    Luo, Wei; Hacke, Peter; Singh, Jai Prakash; Chai, Jing; Wang, Yan; Ramakrishna, Seeram; Aberle, Armin G.; Khoo, Yong Sheng

    2017-01-01

    A temperature correction methodology for in-situ dark I-V(DIV) characterization of conventional p-type crystalline silicon photovoltaic (PV) modules undergoing potential-induced degradation (PID) is proposed.

  8. The levelized cost of energy for distributed PV : a parametric study.

    SciTech Connect

    Goodrich, Alan C.; Cameron, Christopher P.

    2010-06-01

    The maturation of distributed solar PV as an energy source requires that the technology no longer compete on module efficiency and manufacturing cost ($/Wp) alone. Solar PV must yield sufficient energy (kWh) at a competitive cost (c/kWh) to justify its system investment and ongoing maintenance costs. These metrics vary as a function of system design and interactions between parameters, such as efficiency and area-related installation costs. The calculation of levelized cost of energy includes energy production and costs throughout the life of the system. The life of the system and its components, the rate at which performance degrades, and operation and maintenance requirements all affect the cost of energy. Cost of energy is also affected by project financing and incentives. In this paper, the impact of changes in parameters such as efficiency and in assumptions about operating and maintenance costs, degradation rate and system life, system design, and financing will be examined in the context of levelized cost of energy.

  9. NREL Determines Better Testing Methods for Photovoltaic Module Durability (Fact Sheet), NREL Highlights, Research & Development

    SciTech Connect

    Not Available

    2011-11-01

    NREL discoveries will enable manufacturers to produce more robust photovoltaic modules. Over the past decade, some photovoltaic (PV) modules have experienced power losses because of the system voltage stress that modules experience in fielded arrays. This is partly because qualification tests and standards do not adequately evaluate the durability of modules that undergo the long-term effects of high voltage. Scientists at the National Renewable Energy Laboratory (NREL) tried various testing methods and stress levels to demonstrate module durability to system voltage potential-induced degradation (PID) mechanisms. The results of these accelerated tests, along with outdoor testing, were used to estimate the acceleration factors needed to more accurately evaluate the durability of modules to system voltage stress. NREL was able to determine stress factors, levels, and methods for testing based on the stresses experienced by modules in the field. These results, in combination with those in the literature, suggest that constant stress with humidity and system voltage is more damaging than stress applied intermittently or with periods of recovery comprising hot and dry conditions or alternating bias in between. NREL has determined some module constructions to be extremely durable to PID. These findings will help the manufacturers of PV materials and components produce more durable products that better satisfy their customers. NREL determined that there is rapid degradation of some PV modules under system voltage stress and evaluated degradation rates in the field to develop more accurate accelerated testing methods. PV module manufacturers will be better able to choose robust materials and durable designs and guarantee sturdier, longer-lasting products. As PV modules become more durable, and thus more efficient over the long term, the risks and the cost of PV power will be reduced.

  10. Estimation of Curve Tracing Time in Supercapacitor based PV Characterization

    NASA Astrophysics Data System (ADS)

    Basu Pal, Sudipta; Das Bhattacharya, Konika; Mukherjee, Dipankar; Paul, Debkalyan

    2017-01-01

    Smooth and noise-free characterisation of photovoltaic (PV) generators have been revisited with renewed interest in view of large size PV arrays making inroads into the urban sector of major developing countries. Such practice has recently been observed to be confronted by the use of a suitable data acquisition system and also the lack of a supporting theoretical analysis to justify the accuracy of curve tracing. However, the use of a selected bank of supercapacitors can mitigate the said problems to a large extent. Assuming a piecewise linear analysis of the V-I characteristics of a PV generator, an accurate analysis of curve plotting time has been possible. The analysis has been extended to consider the effect of equivalent series resistance of the supercapacitor leading to increased accuracy (90-95%) of curve plotting times.

  11. Recent developments in high-efficiency PV cells

    SciTech Connect

    Deb, S.

    2000-05-22

    Enormous progress has been made in recent years on a number of photovoltaic (PV) materials and devices in terms of conversion efficiencies. Ultrahigh-efficiency (>30{percent}) PV cells have been fabricated from gallium arsenide (GaAs) and its ternary alloys such as gallium indium phosphide (GaInP{sub 2}). The high-efficiency GaAs-based solar cells are being produced on a commercial scale, particularly for space applications. Efficiencies in the range of 18{percent} to 24{percent} have been achieved in traditional silicon-based devices fabricated from both multicrystalline and single-crystal materials. Major advances in efficiency have also been made on various thin-film solar cells based on amorphous silicon (aSi:H), copper gallium indium diselenide (CIGS), and cadmium telluride materials. This paper gives a brief overview of the recent progress in PV cell efficiencies based on these materials and devices.

  12. Budgeting for Solar PV Plant Operations & Maintenance: Practices and Pricing.

    SciTech Connect

    Enbar, Nadav; Weng, Dean; Klise, Geoffrey Taylor

    2016-01-01

    With rising grid interconnections of solar photovoltaic (PV) systems, greater attention is being trained on lifecycle performance, reliability, and project economics. Expected to meet production thresholds over a 20-30 year timeframe, PV plants require a steady diet of operations and maintenance (O&M) oversight to meet contractual terms. However, industry best practices are only just beginning to emerge, and O&M budgets—given the arrangement of the solar project value chain—appear to vary widely. Based on insights from in-depth interviews and survey research, this paper presents an overview of the utility-scale PV O&M budgeting process along with guiding rationales, before detailing perspectives on current plant upkeep activities and price points largely in the U.S. It concludes by pondering potential opportunities for improving upon existing O&M budgeting approaches in ways that can benefit the industry at-large.

  13. Budgeting for Solar PV Plant Operations & Maintenance: Practices and Pricing.

    SciTech Connect

    Enbar, Nadav; Weng, Dean; Klise, Geoffrey Taylor

    2015-12-01

    With rising grid interconnections of solar photovoltaic (PV) systems, greater attention is being trained on lifecycle performance, reliability, and project economics. Expected to meet production thresholds over a 20-30 year timeframe, PV plants require a steady diet of operations and maintenance (O&M) oversight to meet contractual terms. However, industry best practices are only just beginning to emerge, and O&M budgets—given the arrangement of the solar project value chain—appear to vary widely. Based on insights from in-depth interviews and survey research, this paper presents an overview of the utility-scale PV O&M budgeting process along with guiding rationales, before detailing perspectives on current plant upkeep activities and price points largely in the U.S. It concludes by pondering potential opportunities for improving upon existing O&M budgeting approaches in ways that can benefi t the industry at-large.

  14. Methods, systems and apparatus for controlling operation of two alternating current (AC) machines

    DOEpatents

    Gallegos-Lopez, Gabriel [Torrance, CA; Nagashima, James M [Cerritos, CA; Perisic, Milun [Torrance, CA; Hiti, Silva [Redondo Beach, CA

    2012-02-14

    A system is provided for controlling two AC machines. The system comprises a DC input voltage source that provides a DC input voltage, a voltage boost command control module (VBCCM), a five-phase PWM inverter module coupled to the two AC machines, and a boost converter coupled to the inverter module and the DC input voltage source. The boost converter is designed to supply a new DC input voltage to the inverter module having a value that is greater than or equal to a value of the DC input voltage. The VBCCM generates a boost command signal (BCS) based on modulation indexes from the two AC machines. The BCS controls the boost converter such that the boost converter generates the new DC input voltage in response to the BCS. When the two AC machines require additional voltage that exceeds the DC input voltage required to meet a combined target mechanical power required by the two AC machines, the BCS controls the boost converter to drive the new DC input voltage generated by the boost converter to a value greater than the DC input voltage.

  15. Improved Coefficient Calculator for the California Energy Commission 6 Parameter Photovoltaic Module Model

    SciTech Connect

    Dobos, A. P.

    2012-05-01

    This paper describes an improved algorithm for calculating the six parameters required by the California Energy Commission (CEC) photovoltaic (PV) Calculator module model. Rebate applications in California require results from the CEC PV model, and thus depend on an up-to-date database of module characteristics. Currently, adding new modules to the database requires calculating operational coefficients using a general purpose equation solver - a cumbersome process for the 300+ modules added on average every month. The combination of empirical regressions and heuristic methods presented herein achieve automated convergence for 99.87% of the 5487 modules in the CEC database and greatly enhance the accuracy and efficiency by which new modules can be characterized and approved for use. The added robustness also permits general purpose use of the CEC/6 parameter module model by modelers and system analysts when standard module specifications are known, even if the module does not exist in a preprocessed database.

  16. The Use of Feature Parameters to Asses Barrier Properties of ALD coatings for Flexible PV Substrates

    NASA Astrophysics Data System (ADS)

    Blunt, Liam; Robbins, David; Fleming, Leigh; Elrawemi, Mohamed

    2014-03-01

    This paper reports on the recent work carried out as part of the EU funded NanoMend project. The project seeks to develop integrated process inspection, cleaning, repair and control systems for nano-scale thin films on large area substrates. In the present study flexible photovoltaic films have been the substrate of interest. Flexible PV films are the subject of significant development at present and the latest films have efficiencies at or beyond the level of Si based rigid PV modules. These flexible devices are fabricated on polymer film by the repeated deposition, and patterning, of thin layer materials using roll-to-roll processes, where the whole film is approximately 3um thick prior to encapsulation. Whilst flexible films offer significant advantages in terms of mass and the possibility of building integration (BIPV) they are at present susceptible to long term environmental degradation as a result of water vapor transmission through the barrier layers to the CIGS (Copper Indium Gallium Selenide CuInxGa(1-x)Se2) PV cells thus causing electrical shorts and efficiency drops. Environmental protection of the GIGS cell is provided by a thin (40nm) barrier coating of Al2O3. The highly conformal aluminium oxide barrier layer is produced by atomic layer deposition (ALD) where, the ultra-thin Al2O3 layer is deposited onto polymer thin films before these films encapsulate the PV cell. The surface of the starting polymer film must be of very high quality in order to avoid creating defects in the device layers. Since these defects reduce manufacturing yield, in order to prevent them, a further thin polymer coating (planarization layer) is generally applied to the polymer film prior to deposition. The presence of surface irregularities on the uncoated film can create defects within the nanometre-scale, aluminium oxide, barrier layer and these are measured and characterised. This paper begins by reporting the results of early stage measurements conducted to characterise

  17. Time series power flow analysis for distribution connected PV generation.

    SciTech Connect

    Broderick, Robert Joseph; Quiroz, Jimmy Edward; Ellis, Abraham; Reno, Matthew J.; Smith, Jeff; Dugan, Roger

    2013-01-01

    Distributed photovoltaic (PV) projects must go through an interconnection study process before connecting to the distribution grid. These studies are intended to identify the likely impacts and mitigation alternatives. In the majority of the cases, system impacts can be ruled out or mitigation can be identified without an involved study, through a screening process or a simple supplemental review study. For some proposed projects, expensive and time-consuming interconnection studies are required. The challenges to performing the studies are twofold. First, every study scenario is potentially unique, as the studies are often highly specific to the amount of PV generation capacity that varies greatly from feeder to feeder and is often unevenly distributed along the same feeder. This can cause location-specific impacts and mitigations. The second challenge is the inherent variability in PV power output which can interact with feeder operation in complex ways, by affecting the operation of voltage regulation and protection devices. The typical simulation tools and methods in use today for distribution system planning are often not adequate to accurately assess these potential impacts. This report demonstrates how quasi-static time series (QSTS) simulation and high time-resolution data can be used to assess the potential impacts in a more comprehensive manner. The QSTS simulations are applied to a set of sample feeders with high PV deployment to illustrate the usefulness of the approach. The report describes methods that can help determine how PV affects distribution system operations. The simulation results are focused on enhancing the understanding of the underlying technical issues. The examples also highlight the steps needed to perform QSTS simulation and describe the data needed to drive the simulations. The goal of this report is to make the methodology of time series power flow analysis readily accessible to utilities and others responsible for evaluating

  18. Recovering valuable metals from recycled photovoltaic modules.

    PubMed

    Yi, Youn Kyu; Kim, Hyun Soo; Tran, Tam; Hong, Sung Kil; Kim, Myong Jun

    2014-07-01

    Recovering valuable metals such as Si, Ag, Cu, and Al has become a pressing issue as end-of-life photovoltaic modules need to be recycled in the near future to meet legislative requirements in most countries. Of major interest is the recovery and recycling of high-purity silicon (> 99.9%) for the production of wafers and semiconductors. The value of Si in crystalline-type photovoltaic modules is estimated to be -$95/kW at the 2012 metal price. At the current installed capacity of 30 GW/yr, the metal value in the PV modules represents valuable resources that should be recovered in the future. The recycling of end-of-life photovoltaic modules would supply > 88,000 and 207,000 tpa Si by 2040 and 2050, respectively. This represents more than 50% of the required Si for module fabrication. Experimental testwork on crystalline Si modules could recover a > 99.98%-grade Si product by HNO3/NaOH leaching to remove Al, Ag, and Ti and other metal ions from the doped Si. A further pyrometallurgical smelting at 1520 degrees C using CaO-CaF2-SiO2 slag mixture to scavenge the residual metals after acid leaching could finally produce > 99.998%-grade Si. A process based on HNO3/NaOH leaching and subsequent smelting is proposed for recycling Si from rejected or recycled photovoltaic modules. Implications: The photovoltaic industry is considering options of recycling PV modules to recover metals such as Si, Ag, Cu, Al, and others used in the manufacturing of the PV cells. This is to retain its "green" image and to comply with current legislations in several countries. An evaluation of potential resources made available from PV wastes and the technologies used for processing these materials is therefore of significant importance to the industry. Of interest are the costs of processing and the potential revenues gained from recycling, which should determine the viability of economic recycling of PV modules in the future.

  19. Device to analyze leakage current pathways in photovoltaic modules in real-time

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth; Shiradkar, Narendra; Schneller, Eric

    2014-10-01

    Series connection of PV modules results in buildup of high voltage between the frame and cell circuit which leads to leakage current flow through the module packaging materials. Long term application of high voltage bias results in PV module degradation by Potential Induced Degradation (PID). A novel device called custom laminate is developed at Florida Solar Energy Center that can identify dominant leakage current paths in PV module packaging materials. In this paper, insulation resistance tests are carried out on a commercial 60-cell c-Si module and the nature of leakage current as a function of aluminum foil configuration, applied voltage and duration is studied. The insights gained from the analysis of leakage currents under various circumstances are used to obtain more accurate and reliable measurements from the custom laminate.

  20. Distributed Power Electronics for PV Systems (Presentation)

    SciTech Connect

    Deline, C.

    2011-12-01

    An overview of the benefits and applications of microinverters and DC power optimizers in residential systems. Some conclusions from this report are: (1) The impact of shade is greater than just the area of shade; (2) Additional mismatch losses include panel orientation, panel distribution, inverter voltage window, soiling; (3) Per-module devices can help increase performance, 4-12% or more depending on the system; (4) Value-added benefits (safety, monitoring, reduced design constraints) are helping their adoption; and (5) The residential market is growing rapidly. Efficiency increases, cost reductions are improving market acceptance. Panel integration will further reduce price and installation cost. Reliability remains an unknown.

  1. Progress Toward Sequestering Carbon Nanotubes in PmPV

    NASA Technical Reports Server (NTRS)

    Bley, Richard A.

    2009-01-01

    Sequestration of single-walled carbon nanotubes (SWNTs) in molecules of poly(m-phenylenevinylene-co-2,5-diocty-loxy-p-phenylenevinylene) [PmPV] is a candidate means of promoting dissolution of single-walled carbon nanotubes (SWNTs) into epoxies for making strong, lightweight epoxy-matrix/carbon-fiber composite materials. Bare SWNTs cannot be incorporated because they are not soluble in epoxies. In the present approach, one exploits the tendency of PmPV molecules to wrap themselves around SWNTs without chemically bonding to them.

  2. Amp-hour counting control for PV hybrid power systems

    SciTech Connect

    Hund, T.D.; Thompson, B.

    1997-06-01

    The performance of an amp-hour (Ah) counting battery charge control algorithm has been defined and tested using the Digital Solar Technologies MPR-9400 microprocessor based PV hybrid charge controller. This work included extensive field testing of the charge algorithm on flooded lead-antimony and valve regulated lead-acid (VRLA) batteries. The test results after one-year have demonstrated that PV charge utilization, battery charge control, and battery state of charge (SOC) has been significantly improved by providing maximum charge to the batteries while limiting battery overcharge to manufacturers specifications during variable solar resource and load periods.

  3. Toward integrated PV panels and power electronics using printing technologies

    SciTech Connect

    Ababei, Cristinel; Yuvarajan, Subbaraya; Schulz, Douglas L.

    2010-07-15

    In this paper, we review the latest developments in the area of printing technologies with an emphasis on the fabrication of control-embedded photovoltaics (PV) with on-board active and passive devices. We also review the use of power converters and maximum power point tracking (MPPT) circuits with PV panels. Our focus is on the investigation of the simplest implementations of such circuits in view of their integration with solar cells using printing technologies. We see this concept as potentially enabling toward further cost reduction. Besides a discussion as to feasibility, we shall also present some projections and guidelines toward possible integration. (author)

  4. Selecting Solar: Insights into Residential Photovoltaic (PV) Quote Variation

    SciTech Connect

    Davidson, Carolyn; Margolis, Robert

    2015-10-01

    Before investing in a system, a prospective PV customer must not only have initial concept 'buy in,' but also be able to evaluate the tradeoffs associated with different system parameters. Prospective customers might need to evaluate disparate costs for each system attribute by comparing multiple bids. The difficulty of making such an evaluation with limited information can create a cognitive barrier to proceeding with the investment. This analysis leverages recently available data from EnergySage, an online solar marketplace, to offer the first data-driven characterization of quote variation faced by prospective PV customers, lending early insight into the decisions customers face once they have initial buy-in.

  5. NONLINEAR DIAGNOSTICS USING AC DIPOLES.

    SciTech Connect

    PEGGS,S.

    1999-03-29

    There are three goals in the accurate nonlinear diagnosis of a storage ring. First, the beam must be moved to amplitudes many times the natural beam size. Second, strong and long lasting signals must be generated. Third, the measurement technique should be non-destructive. Conventionally, a single turn kick moves the beam to large amplitudes, and turn-by-turn data are recorded from multiple beam position monitors (BPMs) [1-6]. Unfortunately, tune spread across the beam causes the center of charge beam signal to ''decohere'' on a time scale often less than 100 turns. Filamentation also permanently destroys the beam emittance (in a hadron ring). Thus, the ''strong single turn kick'' technique successfully achieves only one out of the three goals. AC dipole techniques can achieve all three. Adiabatically excited AC dipoles slowly move the beam out to large amplitudes. The coherent signals then recorded last arbitrarily long. The beam maintains its original emittance if the AC dipoles are also turned off adiabatically, ready for further use. The AGS already uses an RF dipole to accelerate polarized proton beams through depolarizing resonances with minimal polarization loss [7]. Similar AC dipoles will be installed in the horizontal and vertical planes of both rings in RHIC [8]. The RHIC AC dipoles will also be used as spin flippers, and to measure linear optical functions [9].

  6. Comparative Study of DC and AC Microgrids in Commercial Buildings Across Different Climates and Operating Profiles: Preprint

    SciTech Connect

    Fregosi, D.; Ravula, S.; Brhlik, D.; Saussele, J.; Frank, S.; Bonnema, E.; Scheib, J.; Wilson, E.

    2015-04-22

    Bosch has developed and demonstrated a novel DC microgrid system designed to maximize utilization efficiency for locally generated photovoltaic energy while offering high reliability, safety, redundancy, and reduced cost compared to equivalent AC systems. Several demonstration projects validating the system feasibility and expected efficiency gains have been completed and additional ones are in progress. This work gives an overview of the Bosch DC microgrid system and presents key results from a large simulation study done to estimate the energy savings of the Bosch DC microgrid over conventional AC systems. The study examined the system performance in locations across the United States for several commercial building types and operating profiles and found that the Bosch DC microgrid uses generated PV energy 6%–8% more efficiently than traditional AC systems.

  7. Transcriptional analysis of the sweet orange interaction with the citrus canker pathogens Xanthomonas axonopodis pv. citri and Xanthomonas axonopodis pv. aurantifolii.

    PubMed

    Cernadas, Raúl Andrés; Camillo, Luciana Rodrigues; Benedetti, Celso Eduardo

    2008-09-01

    Xanthomonas axonopodis pv. citri (Xac) and Xanthomonas axonopodis pv. aurantifolii pathotype C (Xaa) are responsible for citrus canker disease; however, while Xac causes canker on all citrus varieties, Xaa is restricted to Mexican lime, and in sweet oranges it triggers a defence response. To gain insights into the differential pathogenicity exhibited by Xac and Xaa and to survey the early molecular events leading to canker development, a detailed transcriptional analysis of sweet orange plants infected with the pathogens was performed. Using differential display, suppressed subtractive hybridization and microarrays, we identified changes in transcript levels in approximately 2.0% of the approximately 32,000 citrus genes examined. Genes with altered expression in response to Xac/Xaa surveyed at 6 and 48 h post-infection (hpi) were associated with cell-wall modifications, cell division and expansion, vesicle trafficking, disease resistance, carbon and nitrogen metabolism, and responses to hormones auxin, gibberellin and ethylene. Most of the genes that were commonly modulated by Xac and Xaa were associated with basal defences triggered by pathogen-associated molecular patterns, including those involved in reactive oxygen species production and lignification. Significantly, we detected clear changes in the transcriptional profiles of defence, cell-wall, vesicle trafficking and cell growth-related genes in Xac-infected leaves between 6 and 48 hpi. This is consistent with the notion that Xac suppresses host defences early during infection and simultaneously changes the physiological status of the host cells, reprogramming them for division and growth. Notably, brefeldin A, an inhibitor of vesicle trafficking, retarded canker development. In contrast, Xaa triggered a mitogen-activated protein kinase signalling pathway involving WRKY and ethylene-responsive transcriptional factors known to activate downstream defence genes.

  8. Berkeley Program Offers New Option for Financing Residential PV Systems

    SciTech Connect

    Bolinger, Mark A

    2008-07-06

    Readily accessible credit has often been cited as a necessary ingredient to open up the market for residential photovoltaic (PV) systems. Though financing does not reduce the high up-front cost of PV, by spreading that cost over some portion of the system's life, financing can certainly make PV systems more affordable. As a result, a number of states have, in the past, set up special residential loan programs targeting the installation of renewable energy systems and/or energy-efficiency improvements and often featuring low interest rates, longer terms and no-hassle application requirements. Historically, these loan programs have had mixed success (particularly for PV), for a variety of reasons, including a historical lack of homeowner interest in PV, a lack of program awareness, a reduced appeal in a low-interest-rate environment, and a tendency for early PV adopters to be wealthy and not in need of financing. Some of these barriers have begun to fade. Most notably, homeowner interest in PV has grown in some states, particularly those that offer solar rebates. The passage of the Energy Policy Act of 2005 (EPAct 2005), however, introduced one additional roadblock to the success of low-interest PV loan programs: a residential solar investment tax credit (ITC), subject to the Federal government's 'anti-double-dipping' rules. Specifically, the residential solar ITC--equal to 30% of the system's tax basis, capped at $2000--will be reduced or offset if the system also benefits from what is known as 'subsidized energy financing', which is likely to include most government-sponsored low-interest loan programs. Within this context, it has been interesting to note the recent flurry of announcements from a number of U.S cities concerning a new type of PV financing program. Led by the city of Berkeley, Calif., these cities propose to offer their residents the ability to finance the installation of a PV system using increased property tax assessments, rather than a more

  9. Glutamate transport and xanthan gum production in the plant pathogen Xanthomonas axonopodis pv. citri.

    PubMed

    Rojas, Robert; Nishidomi, Sabrina; Nepomuceno, Roberto; Oshiro, Elisa; de Cassia Café Ferreira, Rita

    2013-11-01

    L-glutamate plays a central role in nitrogen metabolism in all living organisms. In the genus Xanthomonas, the nitrogen nutrition is an important factor involved in the xanthan gum production, an important exopolysaccharide with various industrial and biotechnological applications. In this report, we demonstrate that the use of L-glutamate by the phytopathogen Xanthomonas axonopodis pv. citri as a nitrogen source in defined medium significantly increases the production of xanthan gum. This increase is dependent on the L-glutamate concentration. In addition, we have also characterized a glutamate transport system that is dependent on a proton gradient and on ATP and is modulated by amino acids that are structurally related to glutamate. This is the first biochemical characterization of an energy substrate transport system observed in a bacterial phytopathogen with a broad economic and industrial impact due to xanthan gum production.

  10. The influence of active cell design on a monolithic organic photovoltaic module: fabrication and simulation

    NASA Astrophysics Data System (ADS)

    Lyu, Hong-Kun; Sim, Jun Hyoung; Jeong, Seonju; Woo, Sung-Ho; Shin, Jang-Kyoo; Han, Yoon Soo

    2011-09-01

    In this study, the influence of an active cell design on the power conversion efficiency (PCE) of a monolithic organic photovoltaic (OPV) module was investigated using experimental methods and circuit simulation. For circuit simulation using computer simulation-based study, the organic PV cell was described by a circuit-based two-diode model and the modules were simulated under several conditions including shading effect, diode model parameters, series resistance and shunt resistance, etc. A unit organic PV cell as a reference device and four types of monolithic organic PV modules with different active cell length were fabricated together on the same glass substrate. The characteristics of the fabricated unit OPV cell were measured and the electrical parameters were extracted to use them for the simulation of four types of monolithic organic PV modules. To analyze the influence of OPV cell design on the PCE of monolithic organic PV modules, the current-voltage (I-V) characteristic curves and the PCEs of the four type monolithic OPV modules with different active cell length were obtained and compared with the simulated results. The simulated I-V curves were matched well with the measured I-V curves for the four types of monolithic organic PV modules with different active cell length. The highest PCE of the monolithic OPV module was 2.86 % with the active cell length of 11.6 mm. We expect that this work is meaningful to enhance the performance of a monolithic OPV module to a certain extent and it offers a method to design a high-efficiency large-area monolithic OPV module.

  11. Electromigration in thin-film photovoltaic module metallization systems

    NASA Technical Reports Server (NTRS)

    Wen, L.; Mon, G.; Jetter, E.; Ross, R., Jr.

    1988-01-01

    Electromigration as a possible thin-film module failure mechanism was investigated using several specially made, fully aluminized thin-film photovoltaic (TF-PV) modules. The effect of electromigration, as determined experimentally by measuring increases in electrical resistance across scribe lines, can be expressed as the product of a damage function, which correlates degradation rate with operating conditions such as current density and temperature, and a susceptibility function, which is defined by module design parameters, particularly aluminum purity and the configuration of the intercell region. Experimental measurements and derived acceleration factors suggest that open-circuit failure resulting from electromigration should not be a serious problem in present state-of-the-art TF-PV modules. Nevertheless, significant intercell resistance increases can result from long-term electromigration exposure, especially in future high-efficiency modules. The problem can be alleviated, however, by appropriate metallization applications and/or proper design of the intercell region.

  12. Extension to PV OPTICS to include front electrode design in solar cells

    NASA Astrophysics Data System (ADS)

    Guhabiswas, Debraj

    Proper optical designing of solar cells and modules is of paramount importance towards achieving high photovoltaic conversion efficiencies. Modeling softwares such as PV OPTICS, BIRANDY and SUNRAYS have been created to aid such optical designing of cells and modules; but none of these modeling packages take the front metal electrode architecture of a solar cell into account. A new model, has been developed to include the front metal electrode architecture to finished solar cells for optical calculations. This has been implemented in C++ in order to add a new module to PV OPTICS (NREL's photovoltaic modeling tool) to include front metallization patterns for optical design and simulation of solar cells. This new addition also calculates the contribution of light that diffuses out of the illuminated (non-metallized) regions to the solar cell current. It also determines the optical loss caused by the absorption in the front metal and separates metallic losses due to front and back contacts. This added capability also performs the following functions: • calculates the total current that can be generated in a solar cell due to optical absorption in each region, including the region beneath the front metal electrodes for the radiation spectrum of AM 1.5, • calculates various losses in the solar cell due to front electrode shading, metal absorption, and reflectance, • makes a plot of how light is absorbed in the metal as well as silicon under the shaded region in the solar cell. Although Finite Difference Time Domain (FDTD) is the numerical technique of choice to solve Maxwell's equations for a propagating electromagnetic wave, it is both time consuming and very demanding on the computer processors. Furthermore, for complicated geometric structures, FDTD poses various limitations. Hence, ray tracing has been chosen as the means of implementing this new model. This new software has been used to carry out a detailed investigation on the effect of various parameters of

  13. Photovoltaic (PV) Pricing Trends: Historical, Recent, and Near-Term Projections

    SciTech Connect

    Feldman, David; Barbose, Galen; Margolis, Robert; Wiser, Ryan; Darghouth, Naim; Goodrich, Alan

    2012-11-30

    The installed capacity of global and U.S. photovoltaic (PV) systems has soared in recent years, driven by declining PV prices and government incentives. The U.S. Department of Energy’s (DOE) SunShot Initiative aims to make PV cost competitive without incentives by reducing the cost of PV-generated electricity by about 75% between 2010 and 2020. This summary report—based on research at Lawrence Berkeley National Laboratory (LBNL) and the National Renewable Energy Laboratory (NREL)—examines progress in PV price reductions to help DOE and other PV stakeholders manage the transition to a market-driven PV industry, and to provide clarity surrounding the wide variety of potentially conflicting data available about PV system prices.

  14. Draft Genome Sequences of Four Xanthomonas arboricola pv. juglandis Strains Associated with Walnut Blight in Chile

    PubMed Central

    Higuera, Gastón; González-Escalona, Narjol; Véliz, Camila; Vera, Francisca

    2015-01-01

    Xanthomonas arboricola pv. juglandis is an important pathogen responsible for walnut blight outbreaks globally. Here, we report four draft genome sequences of X. arboricola pv. juglandis strains isolated from Chilean walnut trees. PMID:26450732

  15. Draft genome sequences of five Pseudomonas syringae pv. actinidifoliorum strains isolated in France.

    PubMed

    Cunty, Amandine; Cesbron, Sophie; Briand, Martial; Carrère, Sébastien; Poliakoff, Françoise; Jacques, Marie-Agnès; Manceau, Charles

    2016-01-01

    Pseudomonas syringae pv. actinidifoliorum causes necrotic spots on the leaves of Actinidia deliciosa and Actinidia chinensis. P. syringae pv. actinidifoliorum has been detected in New Zealand, Australia, France and Spain. Four lineages were previously identified within the P. syringae pv. actinidifoliorum species group. Here, we report the draft genome sequences of five strains of P. syringae pv. actinidifoliorum representative of lineages 1, 2 and 4, isolated in France. The whole genomes of strains isolated in New Zealand, representative of P. syringae pv. actinidifoliorum lineages 1 and 3, were previously sequenced. The availability of supplementary P. syringae pv. actinidifoliorum genome sequences will be useful for developing molecular tools for pathogen detection and for performing comparative genomic analyses to study the relationship between P. syringae pv. actinidifoliorum and other kiwifruit pathogens, such as P. syringae pv. actinidiae.

  16. Novel in situ series connection for thin film photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Merz, Rainer; Kistner, Jens; Schubert, Markus B.; Werner, Jürgen H.

    2009-08-01

    The monolithically integrated series connection of single solar cell stripes into complete photovoltaic (PV) modules is one of the key advantages of thin film PV technologies. Instead of the well established laser scribing for series connection, this contribution focuses on a novel in situ series connection technology, without breaking the vacuum during module manufacturing, and without the need of costly laser-scribing equipment. Metallic wires or other filaments aligned along the slightly bent substrate, sequentially pattern the solar cell layers for implementing the monolithic series connection, simultaneously with the consecutive evaporation, plasma deposition, and sputtering of the semiconductor and contact layers. In addition to a proof of concept by flexible PV modules, this paper for the first time investigates wire-shading on rigid glass substrates and by multiple adjacent filaments. The results of these studies demonstrate that the in situ series connection is a promising candidate for competing with laser scribing, not only in roll-to-roll production of flexible PV modules, but also in batch or inline processing of standard large-area glass plates. Applying the novel in situ series connection to a laboratory-scale solar cell process, yields 40 cm2 sized PV modules, consisting of ten single junction amorphous silicon n-i-p cells on a flexible polymer foil. The modules' total area efficiency of 3 % is close to the non-optimized efficiency of reference cells of 3.3 %. Wire-shading with wire diameters down to 50 μm proves successful, and thereby projects total interconnection losses F < 5 %, whereas the first experimental modules exhibit F = 15 %.

  17. Intrinsic variability in Pv, RRP size, Ca(2+) channel repertoire, and presynaptic potentiation in individual synaptic boutons.

    PubMed

    Ariel, Pablo; Hoppa, Michael B; Ryan, Timothy A

    2012-01-01

    The strength of individual synaptic contacts is considered a key modulator of information flow across circuits. Presynaptically the strength can be parsed into two key parameters: the size of the readily releasable pool (RRP) and the probability that a vesicle in that pool will undergo exocytosis when an action potential fires (Pv). How these variables are controlled and the degree to which they vary across individual nerve terminals is crucial to understand synaptic plasticity within neural circuits. Here we report robust measurements of these parameters in rat hippocampal neurons and their variability across populations of individual synapses. We explore the diversity of presynaptic Ca(2+) channel repertoires and evaluate their effect on synaptic strength at single boutons. Finally, we study the degree to which synapses can be differentially modified by a known potentiator of presynaptic function, forskolin. Our experiments revealed that both Pv and RRP spanned a large range, even for synapses made by the same axon, demonstrating that presynaptic efficacy is governed locally at the single synapse level. Synapses varied greatly in their dependence on N or P/Q type Ca(2+) channels for neurotransmission, but there was no association between specific channel repertoires and synaptic efficacy. Increasing cAMP concentration using forskolin enhanced synaptic transmission in a Ca(2+)-independent manner that was inversely related with a synapse's initial Pv, and independent of its RRP size. We propose a simple model based on the relationship between Pv and calcium entry that can account for the variable potentiation of synapses based on initial probability of vesicle fusion.

  18. Selecting Solar. Insights into Residential Photovoltaic (PV) Quote Variation

    SciTech Connect

    Davidson, Carolyn; Margolis, Robert

    2015-10-01

    This analysis leverages available data from EnergySage, an online solar marketplace, to offer the first data-driven characterization of quote variation faced by prospective PV customers, lending early insight into the decisions customers face once they have initial buy-in.

  19. Detection of Pseudomonas savastanoi pv. glycinea in soybean seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter is one of 52 that will compose the second edition of the Laboratory Manual for the Detection of Plant Pathogenic Bacteria from Seeds and other Planting Material, to be published by the American Phytopathological Society. The chapter presents a description of Pseudomonas savastanoi pv. ...

  20. National solar technology roadmap: Wafer-silicon PV

    SciTech Connect

    Sopori, Bhushan

    2007-06-01

    This report applies to all bulk-silicon-based PV technologies, including those based on Czochralski, multicrystalline, float-zone wafers, and melt-grown crystals that are 100 μm or thicker, such as ribbons, sheet, or spheral silicon.