Science.gov

Sample records for dc power distribution

  1. Simultaneous distribution of AC and DC power

    DOEpatents

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  2. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    DOEpatents

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  3. A High Power Density DC-DC Converter for Distributed PV Architectures

    SciTech Connect

    Agamy, Mohammed S; Chi, Song; Elasser, Ahmed; Harfman-Todorovic, Maja; Jiang, Yan; Mueller, Frank; Tao, Fengfeng

    2012-06-01

    In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

  4. Multi-kw dc power distribution system study program

    NASA Technical Reports Server (NTRS)

    Berkery, E. A.; Krausz, A.

    1974-01-01

    The first phase of the Multi-kw dc Power Distribution Technology Program is reported and involves the test and evaluation of a technology breadboard in a specifically designed test facility according to design concepts developed in a previous study on space vehicle electrical power processing, distribution, and control. The static and dynamic performance, fault isolation, reliability, electromagnetic interference characterisitics, and operability factors of high distribution systems were studied in order to gain a technology base for the use of high voltage dc systems in future aerospace vehicles. Detailed technical descriptions are presented and include data for the following: (1) dynamic interactions due to operation of solid state and electromechanical switchgear; (2) multiplexed and computer controlled supervision and checkout methods; (3) pulse width modulator design; and (4) cable design factors.

  5. Topological variations of the inverse dual converter for high-power dc-dc distribution systems

    NASA Astrophysics Data System (ADS)

    Ehsani, Mehrdad; Laskai, Laszlo

    New dc-to-dc converter topologies are presented which are suitable for high density high power supplies. Topological variations of the basic inverse dual converter (IDC) circuit such as the transformer coupled, the multiphase and the multipulse derivation of the single phase IDC have been analyzed and some simulation results have been presented. The single phase IDC offers a buck-boost operation over wide range without transformer, bidirectional power flow, and complementary commutation of the switches. The topologies examined in this paper have additional features such as lower device and component stresses, and smaller filter requirements, resulting in smaller size and weight. Some performance and possible applications are also examined. IDCs for serial and parallel power distribution, and ac tapping of the IDC are discussed.

  6. Solid State Remote Power Controllers for high voltage DC distribution systems

    NASA Technical Reports Server (NTRS)

    Billings, W. W.; Sundberg, G. R.

    1977-01-01

    Presently, hybrid Remote Power Controllers (RPC's) are in production and prototype units are available for systems utilizing 28VDC, 120VDC, 115VAC/400 Hz and 230VAC/400 Hz. This paper describes RPC development in a new area of application: HVDC distribution systems utilizing 270/300VDC. Two RPC current ratings, 1 amp and 2 amps, were selected for development as they are adequate to control 90% of projected system loads. The various aspects and trade-offs encountered in circuit development are discussed with special focus placed on the circuits that see the duress of the high dc potentials. The comprehensive evaluation tests are summarized which confirmed the RPC compliance with the specification and with system/load compatibility requirements. In addition, present technology status and new applications are summarized.

  7. Impact of quasi-dc currents on three-phase distribution transformer installations. Power Systems Technology Program

    SciTech Connect

    McConnell, B.W.; Barnes, P.R.; Tesche, F.M.; Schafer, D.A.

    1992-06-01

    This report summarizes a series of tests designed to determine the response of quasi-dc currents on three-phase power distribution transformers for electric power systems. In general, if the dc injection is limited to the primary side of a step-down transformer, significant harmonic distortion is noted and an increase in the reactive power demand results. For dc injection on the secondary (load) side of the step-down transformer the harmonic content at the secondary side is quite high and saturation occurs with a relatively low level of dc injection; however, the reactive power demand is significantly lower. These tests produced no apparent damage to the transformers. Transformer damage is dependent on the duration of the dc excitation, the level of the excitation, and on thermal characteristics of the transfer. The transformer response time is found to be much shorter than seen in power transformer tests at lower dc injection levels. This shorter response time suggests that the response time is strongly dependent on the injected current levels, and that higher levels of dc injection for shorter durations could produce very high reactive power demands and harmonic distortion within a few tenths of a second. The added reactive power load could result in the blowing of fuses on the primary side of the transformer for even moderate dc injection levels, and neutral currents are quite large under even low-level dc injection. This ``smoking neutral`` results in high-level harmonic injection into equipment via the neutral and in possible equipment failure.

  8. Load converter interactions with the secondary system in the Space Station Freedom power management and distribution dc test bed

    NASA Technical Reports Server (NTRS)

    Lebron, Ramon C.

    1992-01-01

    The NASA LeRC in Cleveland, Ohio, is responsible for the design, development, and assembly of the Space Station Freedom (SSF) Electrical Power System (EPS). In order to identify and understand system level issues during the SSF program design and development phases, a system Power Management and Distribution (PMAD) dc test bed was assembled. Some of the objectives of this test bed facility are the evaluation of, system efficiency, power quality, system stability, and system protection and reconfiguration schemes. In order to provide a realistic operating scenario, dc Load Converter Units are used in the PMAD dc test bed to characterize the user interface with the power system. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. This final regulation is required on the actual space station because the majority of user loads will require voltage levels different from the secondary bus voltage. This paper describes the testing of load converters in an end to end system environment (from solar array to loads) where their interactions and compatibility with other system components are considered. Some of the system effects of interest that are presented include load converters transient behavior interactions with protective current limiting switchgear, load converters ripple effects, and the effects of load converter constant power behavior with protective features such as foldback.

  9. Load converter interactions with the secondary system in the Space Station Freedom power management and distribution DC test bed

    NASA Technical Reports Server (NTRS)

    Lebron, Ramon C.

    1992-01-01

    The NASA LeRC in Cleveland, Ohio, is responsible for the design, development, and assembly of the Space Station Freedom (SSF) Electrical Power System (EPS). In order to identify and understand system level issues during the SSF Program design and development phases, a system Power Management and Distribution (PMAD) DC test bed was assembled. Some of the objectives of this test bed facility are the evaluation of, system efficiency, power quality, system stability, and system protection and reconfiguration schemes. In order to provide a realistic operating scenario, dc Load Converter Units are used in the PMAD dc test bed to characterize the user interface with the power system. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. This final regulation is required on the actual space station because the majority of user loads will require voltage levels different from the secondary bus voltage. This paper describes the testing of load converters in an end to end system environment (from solar array to loads) where their interactions and compatibility with other system components are considered. Some of the system effects of interest that are presented include load converters transient behavior interactions with protective current limiting switchgear, load converters ripple effects, and the effects of load converter constant power behavior with protective features such as foldback.

  10. The state-of-the-art of dc power distribution systems/components for space applications

    NASA Technical Reports Server (NTRS)

    Krauthamer, S.

    1988-01-01

    This report is a survey of the state of the art of high voltage dc systems and components. This information can be used for consideration of an alternative secondary distribution (120 Vdc) system for the Space Station. All HVdc components have been prototyped or developed for terrestrial, aircraft, and spacecraft applications, and are applicable for general space application with appropriate modification and qualification. HVdc systems offer a safe, reliable, low mass, high efficiency and low EMI alternative for Space Station secondary distribution.

  11. Modeling of DC spacecraft power systems

    NASA Technical Reports Server (NTRS)

    Berry, F. C.

    1995-01-01

    Future spacecraft power systems must be capable of supplying power to various loads. This delivery of power may necessitate the use of high-voltage, high-power dc distribution systems to transmit power from the source to the loads. Using state-of-the-art power conditioning electronics such as dc-dc converters, complex series and parallel configurations may be required at the interface between the source and the distribution system and between the loads and the distribution system. This research will use state-variables to model and simulate a dc spacecraft power system. Each component of the dc power system will be treated as a multiport network, and a state model will be written with the port voltages as the inputs. The state model of a component will be solved independently from the other components using its state transition matrix. A state-space averaging method is developed first in general for any dc-dc switching converter, and then demonstrated in detail for the particular case of the boost power stage. General equations for both steady-state (dc) and dynamic effects (ac) are obtained, from which important transfer functions are derived and applied to a special case of the boost power stage.

  12. Modeling of DC spacecraft power systems

    NASA Astrophysics Data System (ADS)

    Berry, F. C.

    1995-07-01

    Future spacecraft power systems must be capable of supplying power to various loads. This delivery of power may necessitate the use of high-voltage, high-power dc distribution systems to transmit power from the source to the loads. Using state-of-the-art power conditioning electronics such as dc-dc converters, complex series and parallel configurations may be required at the interface between the source and the distribution system and between the loads and the distribution system. This research will use state-variables to model and simulate a dc spacecraft power system. Each component of the dc power system will be treated as a multiport network, and a state model will be written with the port voltages as the inputs. The state model of a component will be solved independently from the other components using its state transition matrix. A state-space averaging method is developed first in general for any dc-dc switching converter, and then demonstrated in detail for the particular case of the boost power stage. General equations for both steady-state (dc) and dynamic effects (ac) are obtained, from which important transfer functions are derived and applied to a special case of the boost power stage.

  13. Test and evaluation of load converter topologies used in the Space Station Freedom Power Management and distribution DC test bed

    NASA Technical Reports Server (NTRS)

    Lebron, Ramon C.; Oliver, Angela C.; Bodi, Robert F.

    1991-01-01

    Power components hardware in support of the Space Station Freedom dc Electrical Power System were tested. One type of breadboard hardware tested is the dc Load Converter Unit, which constitutes the power interface between the electric power system and the actual load. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. Three load converters were tested: a series resonant converter, a series inductor switchmode converter, and a switching full-bridge forward converter. The topology, operation principles, and tests results are described, in general. A comparative analysis of the three units is given with respect to efficiency, regulation, short circuit behavior (protection), and transient characteristics.

  14. Test and evaluation of load converter topologies used in the Space Station Freedom power management and distribution dc test bed

    NASA Technical Reports Server (NTRS)

    Lebron, Ramon C.; Oliver, Angela C.; Bodi, Robert F.

    1991-01-01

    Power components hardware in support of the Space Station freedom dc Electric Power System were tested. One type of breadboard hardware tested is the dc Load Converter Unit, which constitutes the power interface between the electric power system and the actual load. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. Three load converters were tested: a series resonant converter, a series inductor switch-mode converter, and a switching full-bridge forward converter. The topology, operation principles, and test results are described, in general. A comparative analysis of the three units is given with respect to efficiency, regulation, short circuit behavior (protection), and transient characteristics.

  15. DC-DC powering for the CMS pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, Lutz; Fleck, Martin; Friedrichs, Marcel; Hensch, Richard; Karpinski, Waclaw; Klein, Katja; Rittich, David; Sammet, Jan; Wlochal, Michael

    2013-12-01

    The CMS experiment plans to replace its silicon pixel detector with a new one with improved rate capability and an additional detection layer at the end of 2016. In order to cope with the increased number of detector modules the new pixel detector will be powered via DC-DC converters close to the sensitive detector volume. This paper reviews the DC-DC powering scheme and reports on the ongoing R&D program to develop converters for the pixel upgrade. Design choices are discussed and results from the electrical and thermal characterisation of converter prototypes are shown. An emphasis is put on system tests with up to 24 converters. The performance of pixel modules powered by DC-DC converters is compared to conventional powering. The integration of the DC-DC powering scheme into the pixel detector is described and system design issues are reviewed.

  16. Arcing on dc power systems

    NASA Technical Reports Server (NTRS)

    Moores, Greg; Heller, R. P.; Sutanto, Surja; Dugal-Whitehead, Norma R.

    1992-01-01

    Unexpected and undesirable arcing on dc power systems can produce hazardous situations aboard space flights. The potential for fire and shock might exist in a situation where there is a broken conductor, a loose power connection, or a break in the insulation of the power cable. Such arcing has been found to be reproducible in a laboratory environment. Arcing tests show that the phenomena can last for several seconds and yet be undetectable by present protection schemes used in classical power relaying and remote power controller applications. This paper characterizes the arcing phenomena and suggests future research that is needed.

  17. DC-Powered Jumping Ring

    ERIC Educational Resources Information Center

    Jeffery, Rondo N.; Farhang, Amiri

    2016-01-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

  18. The DC-DC conversion power system of the CMS Phase-1 pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, L.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Schmitz, St.; Wlochal, M.

    2015-01-01

    The pixel detector of the CMS experiment will be exchanged during the year-end technical stop in 2016/2017, as part of the experiment's Phase-1 upgrade. The new device will feature approximately twice the number of readout channels, and consequently the power consumption will be doubled. By moving to a DC-DC conversion powering scheme, it is possible to power the new pixel detector with the existing power supplies and cable plant. The power system of the Phase-1 pixel detector is described and the performance of the new components, including DC-DC converters, DC-DC converter motherboards and various power distribution boards, is detailed. The outcome of system tests in terms of electrical behaviour, thermal management and pixel module performance is discussed.

  19. The dc power circuits: A compilation

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A compilation of reports concerning power circuits is presented for the dissemination of aerospace information to the general public as part of the NASA Technology Utilization Program. The descriptions for the electronic circuits are grouped as follows: dc power supplies, power converters, current-voltage power supply regulators, overload protection circuits, and dc constant current power supplies.

  20. High voltage DC power supply

    DOEpatents

    Droege, T.F.

    1989-12-19

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively. 7 figs.

  1. High voltage DC power supply

    DOEpatents

    Droege, Thomas F.

    1989-01-01

    A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively.

  2. Variable load automatically tests dc power supplies

    NASA Technical Reports Server (NTRS)

    Burke, H. C., Jr.; Sullivan, R. M.

    1965-01-01

    Continuously variable load automatically tests dc power supplies over an extended current range. External meters monitor current and voltage, and multipliers at the outputs facilitate plotting the power curve of the unit.

  3. Bifurcation Analysis of a DC-DC Bidirectional Power Converter Operating with Constant Power Loads

    NASA Astrophysics Data System (ADS)

    Cristiano, Rony; Pagano, Daniel J.; Benadero, Luis; Ponce, Enrique

    Direct current (DC) microgrids (MGs) are an emergent option to satisfy new demands for power quality and integration of renewable resources in electrical distribution systems. This work addresses the large-signal stability analysis of a DC-DC bidirectional converter (DBC) connected to a storage device in an islanding MG. This converter is responsible for controlling the balance of power (load demand and generation) under constant power loads (CPLs). In order to control the DC bus voltage through a DBC, we propose a robust sliding mode control (SMC) based on a washout filter. Dynamical systems techniques are exploited to assess the quality of this switching control strategy. In this sense, a bifurcation analysis is performed to study the nonlinear stability of a reduced model of this system. The appearance of different bifurcations when load parameters and control gains are changed is studied in detail. In the specific case of Teixeira Singularity (TS) bifurcation, some experimental results are provided, confirming the mathematical predictions. Both a deeper insight in the dynamic behavior of the controlled system and valuable design criteria are obtained.

  4. AC and DC power transmission

    SciTech Connect

    Not Available

    1985-01-01

    The technical and economic assessment of AC and DC transmission systems; long distance transmission, cable transmission, system inter-connection, voltage support, reactive compensation, stabilisation of systems; parallel operation of DC links with AC systems; comparison between alternatives for particular schemes. Design and application equipment: design, testing and application of equipment for HVDC, series and shunt static compensated AC schemes, including associated controls. Installations: overall design of stations and conductor arrangements for HVDC, series and shunt static AC schemes including insulation co-ordination. System analysis and modelling.

  5. DC-DC Converter Topology Assessment for Large Scale Distributed Photovoltaic Plant Architectures

    SciTech Connect

    Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Sabate, Juan A; Steigerwald, Robert L; Jiang, Yan; Essakiappan, Somasundaram

    2011-07-01

    Distributed photovoltaic (PV) plant architectures are emerging as a replacement for the classical central inverter based systems. However, power converters of smaller ratings may have a negative impact on system efficiency, reliability and cost. Therefore, it is necessary to design converters with very high efficiency and simpler topologies in order not to offset the benefits gained by using distributed PV systems. In this paper an evaluation of the selection criteria for dc-dc converters for distributed PV systems is performed; this evaluation includes efficiency, simplicity of design, reliability and cost. Based on this evaluation, recommendations can be made as to which class of converters is best fit for this application.

  6. dc power system for deuteron accelerator

    SciTech Connect

    Creek, K.O.; Liska, D.J.

    1981-01-01

    The Fusion Materials Irradiation Test (FMIT) Facility dc power system provides excitation current for all linac and High-Energy Beam Transport (HEBT) quadrupole and bending magnets, excitation for horizontal and vertical beam steering, and current-bypass shunts.

  7. DC/DC Power Converter for Super-Capacitor Supplied by Electric Power Splitter

    NASA Astrophysics Data System (ADS)

    Haubert, T.; Mindl, P.

    The aim of the article is design of DC/DC converter and discussing of problematic supply using electric power splitter. The electric power splitter with AC/DC converter is source for the DC/DC converter, which is dedicated for charging and discharging of hybrid car drive super-capacitor energy storage. The electric power splitter is synchronous machine with two rotating parts. First rotor contains permanent magnet and the second rotor contains three-phase windings. The amplitude of output voltage depends on difference between first and second rotor speed. The main role of the DC/DC converter is to optimize energy content in super-capacitor storage used to acceleration and deceleration driving period of the passenger car with hybrid electric vehicle (HEV) drive system using electric power splitter.

  8. DC to DC power converters and methods of controlling the same

    DOEpatents

    Steigerwald, Robert Louis; Elasser, Ahmed; Sabate, Juan Antonio; Todorovic, Maja Harfman; Agamy, Mohammed

    2012-12-11

    A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.

  9. Modeling Microinverters and DC Power Optimizers in PVWatts

    SciTech Connect

    MacAlpine, S.; Deline, C.

    2015-02-01

    Module-level distributed power electronics including microinverters and DC power optimizers are increasingly popular in residential and commercial PV systems. Consumers are realizing their potential to increase design flexibility, monitor system performance, and improve energy capture. It is becoming increasingly important to accurately model PV systems employing these devices. This document summarizes existing published documents to provide uniform, impartial recommendations for how the performance of distributed power electronics can be reflected in NREL's PVWatts calculator (http://pvwatts.nrel.gov/).

  10. Hybrid-Circuit Module For Dc-To-Dc Power Converter

    NASA Technical Reports Server (NTRS)

    Vorperian, Vatche; Detwiler, Robert; Karmon, Dan

    1996-01-01

    Power hybrid module is general-purpose power-switching module providing flexibility in design and application. Complete dc-to-dc power converter constructed by adding input/output filters and feedback circuitry to module to suit specific application.

  11. Combined Operation of AC and DC Distribution System with Distributed Generation Units

    NASA Astrophysics Data System (ADS)

    Noroozian, Reza; Abedi, Mehrdad; Gharehpetian, Gevorg

    2010-07-01

    This paper presents a DC distribution system which has been supplied by external AC systems as well as local DG units in order to demonstrate an overall solution to power quality issue. In this paper, the proposed operation method is demonstrated by simulation of power transfer between external AC systems, DG units, AC and DC loads. The power flow control in DC distribution system has been achieved by network converters and DG converters. Also, the mathematical model of the network, DG and load converters are obtained by using the average technique, which allows converter systems accurately simulated and control strategies for this converters is achieved. A suitable control strategy for network converters has been proposed that involves DC voltage droop regulator and novel instantaneous power regulation scheme. Also, a novel control technique has been proposed for DG converters. In this paper, a novel control system based on stationary and synchronously rotating reference frame has been proposed for load converters for supplying AC loads connected to the DC bus by balanced voltages. The several case studies have been studied based on proposed methods. The simulation results show that DC distribution systems including DG units can improve the power quality at the point of common coupling (PCC) in the power distribution system or industrial power system.

  12. A High Efficiency DC-DC Converter Topology Suitable for Distributed Large Commercial and Utility Scale PV Systems

    SciTech Connect

    Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Steigerwald, Robert L; Sabate, Juan A; Chi, Song; McCann, Adam J; Zhang, Li; Mueller, Frank

    2012-09-01

    In this paper a DC-DC power converter for distributed photovoltaic plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter also allows for a simplified maximum power point tracker design using fewer measurements

  13. DC-DC power converter research for Orbiter/Station power exchange

    NASA Technical Reports Server (NTRS)

    Ehsani, M.

    1993-01-01

    This project was to produce innovative DC-DC power converter concepts which are appropriate for the power exchange between the Orbiter and the Space Station Freedom (SSF). The new converters must interface three regulated power buses on SSF, which are at different voltages, with three fuel cell power buses on the Orbiter which can be at different voltages and should be tracked independently. Power exchange is to be bi-directional between the SSF and the Orbiter. The new converters must satisfy the above operational requirements with better weight, volume, efficiency, and reliability than is available from the present conventional technology. Two families of zero current DC-DC converters were developed and successfully adapted to this application. Most of the converters developed are new and are presented.

  14. Power Network impedance effects on noise emission of DC-DC converters

    NASA Astrophysics Data System (ADS)

    Esteban, M. C.; Arteche, F.; Iglesias, M.; Gimeno, A.; Arcega, F. J.; Johnson, M.; Cooper, W. E.

    2012-01-01

    The characterization of electromagnetic noise emissions of DC-DC converters is a critical issue that has been analyzed during the desing phase of CMS tracker upgrade. Previous simulation studies showed important variations in the level of conducted emissions when DC-DC converters are loaded/driven by different impedances and power network topologies. Several tests have been performed on real DC-DC converters to validate the Pspice model and simulation results. This paper presents these test results. Conducted noise emissions at the input and at the output terminals of DC-DC converters has been measured for different types of power and FEE impedances. Special attention has been paid to influence on the common-mode emissions by the carbon fiber material used to build the mechanical structure of the central detector. These study results show important recommendations and criteria to be applied in order to decrease the system noise level when integrating the DC-DC.

  15. Development of a DC-DC conversion powering scheme for the CMS Phase-1 pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, L.; Fimmers, C.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Rittich, D.; Sammet, J.; Wlochal, M.

    2014-01-01

    A novel powering scheme based on the DC-DC conversion technique will be exploited to power the CMS Phase-1 pixel detector. DC-DC buck converters for the CMS pixel project have been developed, based on the AMIS5 ASIC designed by CERN. The powering system of the Phase-1 pixel detector is described and the performance of the converter prototypes is detailed, including power efficiency, stability of the output voltage, shielding, and thermal management. Results from a test of the magnetic field tolerance of the DC-DC converters are reported. System tests with pixel modules using many components of the future pixel barrel system are summarized. Finally first impressions from a pre-series of 200 DC-DC converters are presented.

  16. Multi-KW dc distribution system technology research study

    NASA Technical Reports Server (NTRS)

    Dawson, S. G.

    1978-01-01

    The Multi-KW DC Distribution System Technology Research Study is the third phase of the NASA/MSFC study program. The purpose of this contract was to complete the design of the integrated technology test facility, provide test planning, support test operations and evaluate test results. The subjet of this study is a continuation of this contract. The purpose of this continuation is to study and analyze high voltage system safety, to determine optimum voltage levels versus power, to identify power distribution system components which require development for higher voltage systems and finally to determine what modifications must be made to the Power Distribution System Simulator (PDSS) to demonstrate 300 Vdc distribution capability.

  17. High power density dc/dc converter: Component selection and design

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1989-01-01

    Further work pertaining to design considerations for the new high power, high frequency dc/dc converters is discussed. The goal of the project is the development of high power, high power density dc/dc converters at power levels in the multi-kilowatt to megawatt range for aerospace applications. The prototype converter is rated for 50 kW at a switching frequency of 50 kHz, with an input voltage of 200 Vdc and an output of 2000 Vdc. The overall power density must be in the vicinity of 0.2 to 0.3 kg/kW.

  18. Low dose failures of hardened DC-DC power converters

    NASA Technical Reports Server (NTRS)

    Lehman, J.; Yui, C.; Rax, B. G.; Miyahira, T. F.; Weideman, M.; Schrick, P.; Swift, G. M.; Johnston, A. H.

    2002-01-01

    Box-level total dose testing of the FOG (Fiber Optic Gyro) by IXSEA at ESA's GammabeamFacility were abruptly terminated at 8krad (Si) due to catastrophic failure (complete shutdown). This was unexpected because all components within the gyro were supposedly radiation tolerant. Further testing showed that the components responsible for the failure were two DC-DC converters, manufactured by Interpoint, that stopped regulating shortly before shutdown. This paper summarizes diagnostic test results for the converters to determine the underlying cause of the unexpected failure at low levels of radiation.

  19. Multiple-DC-Inputs Direct Electric Power Converter D-EPC with DC Power Sources Connected in Series

    NASA Astrophysics Data System (ADS)

    Yoshimoto, Kantaro; Satou, Shou; Maikawa, Kengo; Takahashi, Kouji

    A series-type multiple-dc-inputs direct electric power converter (D-EPC) has been developed. The D-EPC is a multiple-dc-inputs inverter, and it can eliminate the need for a dc/dc converter that is generally used in conventional converter/inverter systems. The original D-EPC has two positive terminals and a negative terminal in common. Each upper arm between the positive terminal and the ac output is built with a bidirectional switch to prevent short circuit. In the series-type D-EPC, the input power sources are connected in series, thus, the number of bidirectional switches can be reduced and the series voltage can be used in the motor drive system. A new pulse width modulation (PWM) generation technique to drive switching devices in the series-type D-EPC has also been developed. Tests have confirmed that the motor can be operated by controlling the power distribution and that a series voltage can be used.

  20. Research on Load Energy Efficiency of DC Power Supply

    NASA Astrophysics Data System (ADS)

    Yue, Qing; Sun, Yiwei; Li, Ke; Li, Mengyu

    Traditional distribution network based on AC current has severely suffered from low efficiency in actual application, especially when an increasing numbers of home appliances are technically rely on DC current. In this paper, the energy efficiency of DC distribution system was analysed by means of comparison with traditional AC system. Firstly four types of typical appliances were discussed in terms of energy efficiency, which are the server, air conditioner, laptop computer and lighting. And then Models were further built up to perform the case study of three familiar situations in modern life, namely a typical living apartment, an office building and a data center. Finally, the power efficiencies of the three buildings were sorted up for comparison and analysis.

  1. Research study on multi-KW-DC distribution system

    NASA Technical Reports Server (NTRS)

    Berkery, E. A.; Krausz, A.

    1975-01-01

    A detailed definition of the HVDC test facility and the equipment required to implement the test program are provided. The basic elements of the test facility are illustrated, and consist of: the power source, conventional and digital supervision and control equipment, power distribution harness and simulated loads. The regulated dc power supplies provide steady-state power up to 36 KW at 120 VDC. Power for simulated line faults will be obtained from two banks of 90 ampere-hour lead-acid batteries. The relative merits of conventional and multiplexed power control will be demonstrated by the Supervision and Monitor Unit (SMU) and the Automatically Controlled Electrical Systems (ACES) hardware. The distribution harness is supported by a metal duct which is bonded to all component structures and functions as the system ground plane. The load banks contain passive resistance and reactance loads, solid state power controllers and active pulse width modulated loads. The HVDC test facility is designed to simulate a power distribution system for large aerospace vehicles.

  2. Analysis of a class of pulse modulated dc-to-dc power converters

    NASA Technical Reports Server (NTRS)

    Burger, P.

    1975-01-01

    The basic operational characteristics of dc-to-dc converters are analyzed. The basic physical characteristics of power converters are identified. A simple class of dc-to-dc power converters is chosen which could satisfy any set of operating requirements. Three different controlling methods in this class are described in detail. Necessary conditions for the stability of these converters are measured through analog computer simulation. These curves are related to other operational characteristics, such as ripple and regulation. Finally, further research is suggested for the solution of the physical design of absolutely stable, reliable, and efficient power converters of this class.

  3. High power dc/dc and dc/ac electrical power conversion techniques developed

    NASA Technical Reports Server (NTRS)

    Berryman, G.; White, W. T.

    1967-01-01

    Small magnetic amplifiers pass square waves through transformers and provide regulation by varying the pulse width on the secondary of the output power transformers. This pulse duration modulation is provided by a control rectifier technique or a phase-shift technique.

  4. A Reduced-Part, Triple-Voltage DC-DC Converter for Electric Vehicle Power Management

    SciTech Connect

    Su, Gui-Jia; Tang, Lixin

    2007-01-01

    Electrical power systems in future hybrid and fuel cell vehicles may consist of three voltage nets; 14 V, 42 V and high voltage (>200 V) buses. A soft-switched, bi-directional dc-dc converter using only four switches was proposed for interconnecting the three nets. This paper presents a reduced- part dc-dc converter, which decreases the converter cost while retaining all the favorable features of the original topology. Simulation and experimental data are included to verify a simple power flow control scheme.

  5. Efficiency and Regulation of Commercial Low Power DC/DC Converter Modules at Low Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2000-01-01

    DC/DC converters that are capable of operating at cryogenic temperatures are anticipated to play an important role in the power systems of future NASA deep space missions. Design of these converters to survive cryogenic temperatures will improve the power system performance, and reduce development and launch costs. At the NASA Glenn Research Center Low Temperature Electronics Laboratory, several commercial off-the-shelf dc/dc converter modules were evaluated for their low temperature performance. Various parameters were investigated as a function of temperature, in the range of 20 C to -190 C. Data pertaining to the efficiency and voltage regulation of the tested converters is presented and discussed.

  6. Reliability and performance studies of DC-DC conversion powering scheme for the CMS pixel tracker at SLHC

    NASA Astrophysics Data System (ADS)

    Todri, A.; Perera, L.; Rivera, R.; Kwan, S.

    2010-12-01

    The upgrades of the Large Hadron Collider (LHC) introduce a significant challenge to the power distribution of the detectors. DC-DC conversion is the preferred powering scheme proposed to be integrated for the CMS tracker to deliver high input voltage levels and performing a step-down conversion nearby the detector modules. In this work, we propose a step-up/step-down powering scheme by performing voltage step up at the CAEN supply unit and voltage step down near the detector. We designed step-up converters and investigate the pixel performance and power loss on the FPIX power distribution system. Tests are performed using the PSI46 pixel readout chips on a forward pixel panel module and the DC-DC converters developed at CERN and Fermilab. Reliability studies include the voltage drop measurements on the readout chips and the power supply noise generated from the converter. Performance studies include pixel noise and threshold dispersion results. Comparison between step-down only and step-up/step-down conversion powering schemes are provided.

  7. Intelligent Systems for Power Management and Distribution

    NASA Technical Reports Server (NTRS)

    Button, Robert M.

    2002-01-01

    The motivation behind an advanced technology program to develop intelligent power management and distribution (PMAD) systems is described. The program concentrates on developing digital control and distributed processing algorithms for PMAD components and systems to improve their size, weight, efficiency, and reliability. Specific areas of research in developing intelligent DC-DC converters and distributed switchgear are described. Results from recent development efforts are presented along with expected future benefits to the overall PMAD system performance.

  8. High power density dc/dc converter: Selection of converter topology

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1990-01-01

    The work involved in the identification and selection of a suitable converter topology is described. Three new dc/dc converter topologies are proposed: Phase-Shifted Single Active Bridge DC/DC Converter; Single Phase Dual Active Bridges DC/DC Converter; and Three Phase Dual Active Bridges DC/DC Converter (Topology C). The salient features of these topologies are: (1) All are minimal in structure, i.e., each consists of an input and output bridge, input and output filter and a transformer, all components essential for a high power dc/dc conversion process; (2) All devices of both the bridges can operate under near zero-voltage conditions, making possible a reduction of device switching losses and hence, an increase in switching frequency; (3) All circuits operate at a constant frequency, thus simplifying the task of the magnetic and filter elements; (4) Since, the leakage inductance of the transformer is used as the main current transfer element, problems associated with the diode reverse recovery are eliminated. Also, this mode of operation allows easy paralleling of multiple modules for extending the power capacity of the system; (5) All circuits are least sensitive to parasitic impedances, infact the parasitics are efficently utilized; and (6) The soft switching transitions, result in low electromagnetic interference. A detailed analysis of each topology was carried out. Based on the analysis, the various device and component ratings for each topology operating at an optimum point, and under the given specifications, are tabulated and discussed.

  9. Power conditioning for large dc motors for space flight applications

    NASA Technical Reports Server (NTRS)

    Veatch, Martin S.; Anderson, Paul M.; Eason, Douglas J.; Landis, David M.

    1988-01-01

    The design and performance of a prototype power-conditioning system for use with large brushless dc motors on NASA space missions are discussed in detail and illustrated with extensive diagrams, drawings, and graphs. The 5-kW 8-phase parallel module evaluated here would be suitable for use in the Space Shuttle Orbiter cargo bay. A current-balancing magnetic assembly with low distributed inductance permits high-speed current switching from a low-voltage bus as well as current balancing between parallel MOSFETs.

  10. A DC-DC conversion powering scheme for the CMS Phase-1 pixel upgrade

    NASA Astrophysics Data System (ADS)

    Feld, L.; Fleck, M.; Friedrichs, M.; Hensch, R.; Karpinski, W.; Klein, K.; Sammet, J.; Wlochal, M.

    2013-02-01

    The CMS pixel detector was designed for a nominal instantaneous LHC luminosity of 1ṡ1034 cm-2s-1. During Phase-1 of the LHC upgrade, the instantaneous luminosity will be increased to about twice this value. To preserve the excellent performance of the pixel detector despite the increase in particle rates and track densities, the CMS Collaboration foresees the exchange of its pixel detector in the shutdown 2016/2017. The new pixel detector will be improved in many respects, and will comprise twice the number of readout channels. A powering scheme based on DC-DC conversion will be adopted, which will enable the provision of the required power with the present cable plant. The powering scheme of the CMS pixel detector will be described, and the performance of prototype DC-DC buck converters will be presented, including power efficiency, system tests with DC-DC converters and pixel modules, thermal management, reliability at low temperature, and studies of potential frequency locking between DC-DC converters.

  11. Modelling, simulation and construction of a dc/dc boost power converter: a school experimental system

    NASA Astrophysics Data System (ADS)

    Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernández-Guzmán, V. M.; Saldaña-González, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

    2012-05-01

    We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders the feasible introduction of this equipment in undergraduate laboratories.

  12. Modelling, Simulation and Construction of a DC/DC Boost Power Converter: A School Experimental System

    ERIC Educational Resources Information Center

    Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

    2012-01-01

    We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders…

  13. The application of standardized control and interface circuits to three dc to dc power converters.

    NASA Technical Reports Server (NTRS)

    Yu, Y.; Biess, J. J.; Schoenfeld, A. D.; Lalli, V. R.

    1973-01-01

    Standardized control and interface circuits were applied to the three most commonly used dc to dc converters: the buck-boost converter, the series-switching buck regulator, and the pulse-modulated parallel inverter. The two-loop ASDTIC regulation control concept was implemented by using a common analog control signal processor and a novel digital control signal processor. This resulted in control circuit standardization and superior static and dynamic performance of the three dc-to-dc converters. Power components stress control, through active peak current limiting and recovery of switching losses, was applied to enhance reliability and converter efficiency.

  14. Lightweight DC-DC Converter with Partial Power Processing and MPPT for a Solar Powered Aircraft

    NASA Astrophysics Data System (ADS)

    Diab-Marzouk, Ahmad

    A lightweight dc-dc partial power processing converter is demonstrated for solar aerospace applications. A system-level model is conceived to determine conformity to payload and target distance objectives, with the Solarship aircraft used as an application example. The concept of partial power processing is utilized to realize a high efficiency lightweight converter that performs Max Peak Power Tracking (MPPT) to transfer power from the aircraft solar array to the high-voltage battery bus. The isolated Cuk is determined to be a suitable converter topology for the application. A small-signal model is derived for control design. The operation of a 400V, 2.7 kW prototype is verified at high frequency (200 kHz), high efficiency (> 98%), small mass (0.604 kg), and uses no electrolytic capacitors. MPPT operation is verified on a 376 V commercial solar installation at The University of Toronto. The prototype serves as an enabling technology for solar aerospace applications.

  15. Experience from design, prototyping and production of a DC-DC conversion powering scheme for the CMS Phase-1 Pixel Upgrade

    NASA Astrophysics Data System (ADS)

    Feld, L.; Karpinski, W.; Klein, K.; Lipinski, M.; Preuten, M.; Rauch, M.; Schmitz, S.; Wlochal, M.

    2016-02-01

    The CMS collaboration has adopted a DC-DC conversion powering scheme for the Phase-1 Upgrade of its pixel detector. DC-DC buck converters with a conversion ratio of around 3 are installed on the support structures, outside of the sensitive tracking region, requiring a re-design of the low and high voltage distribution to the pixel modules. After several years of R&D, the project has entered the production phase. A total of 1800 DC-DC converters are being produced, and rigorous quality assurance and control is being employed during the production process. The testing program is outlined, results from mass production are presented and issues that have been encountered are described. In addition, two system level challenges, namely the choice of output voltage in the presence of large, load-dependent voltage drops, and the thermal management required to remove the heat load caused by the DC-DC converters, are discussed.

  16. Power distribution studies for CMS forward tracker

    SciTech Connect

    Todri, A.; Turqueti, M.; Rivera, R.; Kwan, S.; /Fermilab

    2009-01-01

    The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory is carrying out R&D investigations for the upgrade of the power distribution system of the Compact Muon Solenoid (CMS) Pixel Tracker at the Large Hadron Collider (LHC). Among the goals of this effort is that of analyzing the feasibility of alternative powering schemes for the forward tracker, including DC to DC voltage conversion techniques using commercially available and custom switching regulator circuits. Tests of these approaches are performed using the PSI46 pixel readout chip currently in use at the CMS Tracker. Performance measures of the detector electronics will include pixel noise and threshold dispersion results. Issues related to susceptibility to switching noise will be studied and presented. In this paper, we describe the current power distribution network of the CMS Tracker, study the implications of the proposed upgrade with DC-DC converters powering scheme and perform noise susceptibility analysis.

  17. A Nonlinear Digital Control Solution for a DC/DC Power Converter

    NASA Technical Reports Server (NTRS)

    Zhu, Minshao

    2002-01-01

    A digital Nonlinear Proportional-Integral-Derivative (NPID) control algorithm was proposed to control a 1-kW, PWM, DC/DC, switching power converter. The NPID methodology is introduced and a practical hardware control solution is obtained. The design of the controller was completed using Matlab (trademark) Simulink, while the hardware-in-the-loop testing was performed using both the dSPACE (trademark) rapid prototyping system, and a stand-alone Texas Instruments (trademark) Digital Signal Processor (DSP)-based system. The final Nonlinear digital control algorithm was implemented and tested using the ED408043-1 Westinghouse DC-DC switching power converter. The NPID test results are discussed and compared to the results of a standard Proportional-Integral (PI) controller.

  18. Impact of quasi-dc currents on three-phase distribution transformer installations

    SciTech Connect

    McConnell, B.W.; Barnes, P.R. ); Tesche, F.M. , Dallas, TX ); Schafer, D.A. )

    1992-06-01

    This report summarizes a series of tests designed to determine the response of quasi-dc currents on three-phase power distribution transformers for electric power systems. In general, if the dc injection is limited to the primary side of a step-down transformer, significant harmonic distortion is noted and an increase in the reactive power demand results. For dc injection on the secondary (load) side of the step-down transformer the harmonic content at the secondary side is quite high and saturation occurs with a relatively low level of dc injection; however, the reactive power demand is significantly lower. These tests produced no apparent damage to the transformers. Transformer damage is dependent on the duration of the dc excitation, the level of the excitation, and on thermal characteristics of the transfer. The transformer response time is found to be much shorter than seen in power transformer tests at lower dc injection levels. This shorter response time suggests that the response time is strongly dependent on the injected current levels, and that higher levels of dc injection for shorter durations could produce very high reactive power demands and harmonic distortion within a few tenths of a second. The added reactive power load could result in the blowing of fuses on the primary side of the transformer for even moderate dc injection levels, and neutral currents are quite large under even low-level dc injection. This smoking neutral'' results in high-level harmonic injection into equipment via the neutral and in possible equipment failure.

  19. Identifying electrical loads which can use direct photovoltaic dc power

    NASA Astrophysics Data System (ADS)

    Goff, H. C.; Chan, T. S.; Allred, R.; Dale, D. W.; Nichols, J. A.

    1981-11-01

    Direct current energy is used in several industrial and commercial applications including residential appliance type equipment that operates from dc, as used in recreational vehicles. These applications are reviewed to determine the potential for using photovoltaic generated power directly in the respective processes. Generally, the dc load requirements are very high or they require strict regulation. This limits the widespread introduction of PV generated power. The three most promising applications are water desalination, telephone switching stations and fluorescent lighting.

  20. Evaluation of DC electric field distribution of PPLP specimen based on the measurement of electrical conductivity in LN2

    NASA Astrophysics Data System (ADS)

    Hwang, Jae-Sang; Seong, Jae-Kyu; Shin, Woo-Ju; Lee, Jong-Geon; Cho, Jeon-Wook; Ryoo, Hee-Suk; Lee, Bang-Wook

    2013-11-01

    High temperature superconducting (HTS) cable has been paid much attention due to its high efficiency and high current transportation capability, and it is also regarded as eco-friendly power cable for the next generation. Especially for DC HTS cable, it has more sustainable and stable properties compared to AC HTS cable due to the absence of AC loss in DC HTS cable. Recently, DC HTS cable has been investigated competitively all over the world, and one of the key components of DC HTS cable to be developed is a cable joint box considering HVDC environment. In order to achieve the optimum insulation design of the joint box, analysis of DC electric field distribution of the joint box is a fundamental process to develop DC HTS cable. Generally, AC electric field distribution depends on relative permittivity of dielectric materials but in case of DC, electrical conductivity of dielectric material is a dominant factor which determines electric field distribution. In this study, in order to evaluate DC electric field characteristics of the joint box for DC HTS cable, polypropylene laminated paper (PPLP) specimen has been prepared and its DC electric field distribution was analyzed based on the measurement of electrical conductivity of PPLP in liquid nitrogen (LN2). Electrical conductivity of PPLP in LN2 has not been reported yet but it should be measured for DC electric field analysis. The experimental works for measuring electrical conductivity of PPLP in LN2 were presented in this paper. Based on the experimental works, DC electric field distribution of PPLP specimen was fully analyzed considering the steady state and the transient state of DC. Consequently, it was possible to determine the electric field distribution characteristics considering different DC applying stages including DC switching on, DC switching off and polarity reversal conditions.

  1. Kilovolt dc solid state remote power controller development

    NASA Technical Reports Server (NTRS)

    Mitchell, J. T.

    1982-01-01

    The experience gained in developing and applying solid state power controller (SSPC) technology at high voltage dc (HVDC) potentials and power levels of up to 25 kilowatts is summarized. The HVDC switching devices, power switching concepts, drive circuits, and very fast acting overcurrent protection circuits were analyzed. A 25A bipolar breadboard with Darlington connected switching transistor was built. Fault testing at 900 volts was included. A bipolar transistor packaged breadboard design was developed. Power MOSFET remote power controller (RPC) was designed.

  2. A comparative study of electric power distribution systems for spacecraft

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.; King, Roger J.

    1990-01-01

    The electric power distribution systems for spacecraft are compared concentrating on two interrelated issues: the choice between dc and high frequency ac, and the converter/inverter topology to be used at the power source. The relative merits of dc and ac distribution are discussed. Specific converter and inverter topologies are identified and analyzed in detail for the purpose of detailed comparison. Finally, specific topologies are recommended for use in dc and ac systems.

  3. DC-DC Type High-Frequency Link DC for Improved Power Quality of Cascaded Multilevel Inverter

    NASA Astrophysics Data System (ADS)

    Sadikin, Muhammad; Senjyu, Tomonobu; Yona, Atsushi

    2013-06-01

    Multilevel inverters are emerging as a new breed of power converter options for power system applications. Recent advances in power switching devices enabled the suitability of multilevel inverters for high voltage and high power applications because they are connecting several devices in series without the need of component matching. Usually, a transformerless battery energy storage system, based on a cascaded multilevel inverter, is used as a measure for voltage and frequency deviations. System can be reduced in size, weight, and cost of energy storage system. High-frequency link circuit topology is advantageous in realizing compact and light-weight power converters for uninterruptible power supply systems, new energy systems using photovoltaic-cells, fuel-cells and so on. This paper presents a DC-DC type high-frequency link DC (HFLDC) cascaded multilevel inverter. Each converter cell is implemented a control strategy for two H-bridge inverters that are controlled with the same multicarrier pulse width modulation (PWM) technique. The proposed cascaded multilevel inverter generates lower voltage total harmonic distortion (THD) in comparison with conventional cascaded multilevel inverter. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of the proposed cascaded multilevel inverter.

  4. Microfabricated Thin-Film Inductors for High-Frequency DC-DC Power Conversion

    NASA Astrophysics Data System (ADS)

    Yao, Di

    2011-12-01

    Microfabricated V-groove inductors targeted to operate above 10 MHz are investigated. Multilayer nano-granular Co-Zr-O/ZrO2 magnetic thin films are used as the core material of the inductors to improve the magnetic performance of the films deposited on the sidewalls of V-grooves and to control eddy-current loss in the core, which goes up very quickly as frequency increases. A loss model is developed to estimate eddy-current loss in multilayer magnetic thin films considering the effect of displacement current at high frequencies, and the model is applied in the design of V-groove inductors. V-groove inductors using multilayer magnetic thin films are co-optimized with power MOSFETs for 7-V to 3.3-V, 1-A DC-DC buck converters to maximize power handling capability per unit substrate area for given efficiencies. Prototype V-groove inductors are fabricated based on the optimization results, and measured and predicted performance of the inductors match well. The prototype inductors are a promising candidate for high-power-density high-efficiency DC-DC converters. The 7-V to 3.3-V, 1-A converters using prototype V-groove inductors are expected to exhibit power density of 2.5 W/mm2 and efficiency of 86% at 100 MHz, and power density of 0.36 W/mm2 and efficiency of 91% at 11 MHz.

  5. A DC-DC converter based powering scheme for the upgrade of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Feld, L.; Karpinski, W.; Klein, K.; Merz, J.; Sammet, J.; Wlochal, M.

    2011-11-01

    Around 2016, the pixel detector of the CMS experiment will be upgraded. The amount of current that has to be provided to the front-end electronics is expected to increase by a factor of two. Since the space available for cables is limited, this would imply unacceptable power losses in the currently installed supply cables. Therefore it is foreseen to place DC-DC converters close to the front-end electronics, allowing the provision of power at higher voltages, thereby facilitating the supply of the required currents with the present cable plant. This conference report introduces the foreseen powering scheme of the pixel upgrade. For the first time, system tests have been conducted with pixel barrel sensor modules, radiation tolerant DC-DC converters and the full power supply chain of the pixel detector. In addition, studies of the stability of different powering schemes under various conditions are summarized. In particular the impact of large and fast load variations, which are related to the bunch structure of the LHC beam, has been studied.

  6. High-power ac/dc variable load simulator

    NASA Technical Reports Server (NTRS)

    Joncas, K. P.; Birnbach, S.; Bruce, L. D.; Smith, L.

    1975-01-01

    Design of medium-power dynamic electrical load simulator has been extended to permit simulation of ac as well as dc loads and to provide for operation at higher power levels. Simulator is internally protected against reverse voltage, overvoltage, overcurrent, and overload conditions.

  7. Static DC to DC Power Conditioning-Active Ripple Filter, 1 MHZ DC to DC Conversion, and Nonlinear Analysis. Ph.D. Thesis; [voltage regulation and conversion circuitry for spacecraft power supplies

    NASA Technical Reports Server (NTRS)

    Sander, W. A., III

    1973-01-01

    Dc to dc static power conditioning systems on unmanned spacecraft have as their inputs highly fluctuating dc voltages which they condition to regulated dc voltages. These input voltages may be less than or greater than the desired regulated voltages. The design of two circuits which address specific problems in the design of these power conditioning systems and a nonlinear analysis of one of the circuits are discussed. The first circuit design is for a nondissipative active ripple filter which uses an operational amplifier to amplify and cancel the sensed ripple voltage. A dc to dc converter operating at a switching frequency of 1 MHz is the second circuit discussed. A nonlinear analysis of the type of dc to dc converter utilized in designing the 1 MHz converter is included.

  8. Exponentiated power Lindley distribution

    PubMed Central

    Ashour, Samir K.; Eltehiwy, Mahmoud A.

    2014-01-01

    A new generalization of the Lindley distribution is recently proposed by Ghitany et al. [1], called as the power Lindley distribution. Another generalization of the Lindley distribution was introduced by Nadarajah et al. [2], named as the generalized Lindley distribution. This paper proposes a more generalization of the Lindley distribution which generalizes the two. We refer to this new generalization as the exponentiated power Lindley distribution. The new distribution is important since it contains as special sub-models some widely well-known distributions in addition to the above two models, such as the Lindley distribution among many others. It also provides more flexibility to analyze complex real data sets. We study some statistical properties for the new distribution. We discuss maximum likelihood estimation of the distribution parameters. Least square estimation is used to evaluate the parameters. Three algorithms are proposed for generating random data from the proposed distribution. An application of the model to a real data set is analyzed using the new distribution, which shows that the exponentiated power Lindley distribution can be used quite effectively in analyzing real lifetime data. PMID:26644927

  9. Light weight, high power, high voltage dc/dc converter technologies

    NASA Technical Reports Server (NTRS)

    Kraus, Robert; Myers, Ira; Baumann, Eric

    1990-01-01

    Power-conditioning weight reductions by orders of magnitude will be required to enable the megawatt-power-level space systems envisioned by the Strategic Defense Initiative, the Air Force, and NASA. An interagency program has been initiated to develop an 0.1-kg/kW dc/dc converter technology base for these future space applications. Three contractors are in the first phase of a competitive program to develop a megawatt dc/dc converter. Researchers at NASA Lewis Research Center are investigating innovative converter topology control. Three different converter subsystems based on square wave, resonant, and super-resonant topologies are being designed. The components required for the converter designs cover a wide array of technologies. Two different switches, one semiconductor and the other gas, are under development. Issues related to thermal management and material reliability for inductors, transformers, and capacitors are being investigated in order to maximize power density. A brief description of each of the concepts proposed to meet the goals of this program is presented.

  10. Research on design feasibility of high-power light-weight dc-to-dc converters for space power applications

    NASA Technical Reports Server (NTRS)

    Wilson, T. G.

    1981-01-01

    Utilizing knowledge gained from past experience with experimental current-or-voltage step-up dc-to-dc converter power stages operating at output powers up to and in excess of 2 kW, a new experimental current-or-voltage step-up power stage using paralleled bipolar junction transistors (BJTs) as the controlled power switch, was constructed during the current reporting period. The major motivation behind the construction of this new experimental power stage was to improve the circuit layout so as to reduce the effects of stray circuit parasitic inductances resulting from excess circuit lead lengths and circuit loops, and to take advantage of the layout improvements which could be made when some recently-available power components, particularly power diodes and polypropylene filter capacitors, were incorporated into the design.

  11. Power and Energy Management Strategy for Solid State Transformer Interfaced DC Microgrid

    NASA Astrophysics Data System (ADS)

    Yu, Xunwei

    As a result of more and more applications of renewable energy into our ordinary life, how to construct a microgrid (MG) based on the distributed renewable energy resources and energy storages, and then to supply a reliable and flexible power to the conventional power system are the hottest topics nowadays. Comparing to the AC microgrid (AC MG), DC microgrid (DC MG) gets more attentions, because it has its own advantages, such as high efficiency, easy to integrate the DC energy sources and energy storages, and so on. Furthermore, the interaction between DC MG system and the distribution system is also an important and practical issue. In Future Renewable Electric Energy Delivery and Management Systems Center (FREEDM), the Solid State Transformer (SST) is built, which can transform the distribution system to the low AC and DC system directly (usually home application level). Thus, the SST gives a new promising solution for low voltage level MG to interface the distribution level system instead of the traditional transformer. So a SST interfaced DC MG is proposed. However, it also brings new challenges in the design and control fields for this system because the system gets more complicated, which includes distributed energy sources and storages, load, and SST. The purpose of this dissertation is to design a reliable and flexible SST interfaced DC MG based on the renewable energy sources and energy storages, which can operate in islanding mode and SST-enabled mode. Dual Half Bridge (DHB) is selected as the topology for DC/DC converter in DC MG. The DHB operation procedure and average model are analyzed, which is the basis for the system modeling, control and operation. Furthermore, two novel power and energy management strategies are proposed. The first one is a distributed energy management strategy for the DC MG operating in the SST-enabled mode. In this method, the system is not only in distributed control to increase the system reliability, but the power sharing

  12. Power and Energy Management Strategy for Solid State Transformer Interfaced DC Microgrid

    NASA Astrophysics Data System (ADS)

    Yu, Xunwei

    As a result of more and more applications of renewable energy into our ordinary life, how to construct a microgrid (MG) based on the distributed renewable energy resources and energy storages, and then to supply a reliable and flexible power to the conventional power system are the hottest topics nowadays. Comparing to the AC microgrid (AC MG), DC microgrid (DC MG) gets more attentions, because it has its own advantages, such as high efficiency, easy to integrate the DC energy sources and energy storages, and so on. Furthermore, the interaction between DC MG system and the distribution system is also an important and practical issue. In Future Renewable Electric Energy Delivery and Management Systems Center (FREEDM), the Solid State Transformer (SST) is built, which can transform the distribution system to the low AC and DC system directly (usually home application level). Thus, the SST gives a new promising solution for low voltage level MG to interface the distribution level system instead of the traditional transformer. So a SST interfaced DC MG is proposed. However, it also brings new challenges in the design and control fields for this system because the system gets more complicated, which includes distributed energy sources and storages, load, and SST. The purpose of this dissertation is to design a reliable and flexible SST interfaced DC MG based on the renewable energy sources and energy storages, which can operate in islanding mode and SST-enabled mode. Dual Half Bridge (DHB) is selected as the topology for DC/DC converter in DC MG. The DHB operation procedure and average model are analyzed, which is the basis for the system modeling, control and operation. Furthermore, two novel power and energy management strategies are proposed. The first one is a distributed energy management strategy for the DC MG operating in the SST-enabled mode. In this method, the system is not only in distributed control to increase the system reliability, but the power sharing

  13. Controllable Bidirectional dc Power Sources For Large Loads

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Daniels, Taumi S.

    1995-01-01

    System redesigned for greater efficiency, durability, and controllability. Modern electronically controlled dc power sources proposed to supply currents to six electromagnets used to position aerodynamic test model in wind tunnel. Six-phase bridge rectifier supplies load with large current at voltage of commanded magnitude and polarity. Current-feedback circuit includes current-limiting feature giving some protection against overload.

  14. Controls and protective devices for d-c constant potential crane power supplies

    SciTech Connect

    Boldt, A.E. ); Gomez, H.R. )

    1993-07-01

    Many changes have taken place in the American steel industry in recent years. Improvements in the efficiency of processes and systems are noticeable in all areas. To compete in the world market, older, less efficient mills and processes have been eliminated in favor of the new and more efficient. This drive for improvement has been noticeable in the area of electric overhead traveling cranes. Older, obsolete electrical equipment has been replaced by newer, more efficient systems. Improvements in collector systems and use of festooned systems has changed the characteristics of the typical soft d-c crane power supply. The 230-v or less d-c utilization voltage on cranes has now become 250 v (or higher) in many mills. The one large resistive element (ie, collectors, m-g sets, etc) in crane power distribution systems has all but disappeared. The changes in d-c crane power supplies have resulted in the need for changes in protection and in the design of traditional d-c constant potential controls. Higher fault currents are now available, and the 10 to 15 ms inductive time constant, traditionally used to determine the interrupting rating of protective devices (such as fuses and circuit breaker) may no longer be adequate. In addition, constant potential controls designed for 230 v may experience problems at voltages higher than 250 v d-c. This paper will discuss these problems and possible solutions involving testing of protective devices and changes to the traditional d-c crane control system.

  15. Low Temperature Performance of High Power Density DC/DC Converter Modules

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Hammond, Ahmad; Gerber, Scott; Patterson, Richard L.; Overton, Eric

    2001-01-01

    In this paper, two second-generation high power density DC/DC converter modules have been evaluated at low operating temperatures. The power rating of one converter (Module 1) was specified at 150 W with an input voltage range of 36 to 75 V and output voltage of 12 V. The other converter (Module 2) was specified at 100 W with the same input voltage range and an output voltage of 3.3 V. The converter modules were evaluated in terms of their performance as a function of operating temperature in the range of 25 to -140 C. The experimental procedures along with the experimental data obtained are presented and discussed in this paper.

  16. Solid state power systems for DC and RF accelerators

    SciTech Connect

    Adler, R. J.; Richter-Sand, R. J.

    1999-06-10

    Modern accelerator applications require high average and peak powers - particularly RF accelerators and DC accelerators. In many of these applications, it is possible to replace tubes in the power systems with solid state power supplies. In this paper we outline work which we have performed in developing solid state pulsed and CW pulsed power systems for RF linacs and for DC accelerators. We have built and successfully tested a 125 kV, 2.5 MW peak, 60 kW average pulsed power system which is well suited to driving ion beam linacs. This system is modular, with 3 modules capable of driving a large Klystron. The system has been extensively tested with both resistive and fault loads. This type of power supply promises to be less than half as expensive as a conventional thyratron modulator, with considerably more flexibility in pulse duration. We have also powered our Nested High Voltage (NHV) accelerators with a solid state power supply using IGBTs. This type of supply is suitable for both NHV machines, and other Dynamitron style accelerators. Pulsed burst mode excitation of this type of power supply allows us to maintain 1 MV in the NHV accelerator with less than three hundred watts of idling power.

  17. Double layer capacitor/DC-DC converter system applied to constant power loads

    SciTech Connect

    Spyker, R.L.; Nelms, R.M.

    1996-12-31

    Ultracapacitors or double layer capacitors are a recent technology based on the well-known electrochemical phenomenon of extremely high capacitance/unit area in an electrode-electrolyte interface and the high surface area achievable in activated carbon fibers. Capacitors have been tested with a rated capacitance value of 470 F and a rated voltage of 2.3 V. Test voltages as high as 3V (30% above rated) have been used without any short term effect on measured capacitance. At 3 V the total energy storage capacity of one capacitor is 2,100 Joules. With a total volume of 245 cm{sup 3}, the specific energy of this capacitor is 8.5 J/cm{sup 3}. To tap this entire energy store would require running the capacitor to zero voltage. Of course, few loads to which a capacitor bank might be connected can tolerate any drop in input voltage. To remedy this problem a DC/DC converter between the capacitor bank and load is proposed. This paper describes optimization of capacitor bank configurations when supplying a constant power load through a DC/DC converter.

  18. Power system monitoring and source control of the Space Station Freedom DC power system testbed

    NASA Technical Reports Server (NTRS)

    Kimnach, Greg L.; Baez, Anastacio N.

    1992-01-01

    Unlike a terrestrial electric utility which can purchase power from a neighboring utility, the Space Station Freedom (SSF) has strictly limited energy resources; as a result, source control, system monitoring, system protection, and load management are essential to the safe and efficient operation of the SSF Electric Power System (EPS). These functions are being evaluated in the DC Power Management and Distribution (PMAD) Testbed which NASA LeRC has developed at the Power System Facility (PSF) located in Cleveland, Ohio. The testbed is an ideal platform to develop, integrate, and verify power system monitoring and control algorithms. State Estimation (SE) is a monitoring tool used extensively in terrestrial electric utilities to ensure safe power system operation. It uses redundant system information to calculate the actual state of the EPS, to isolate faulty sensors, to determine source operating points, to verify faults detected by subsidiary controllers, and to identify high impedance faults. Source control and monitoring safeguard the power generation and storage subsystems and ensure that the power system operates within safe limits while satisfying user demands with minimal interruptions. System monitoring functions, in coordination with hardware implemented schemes, provide for a complete fault protection system. The objective of this paper is to overview the development and integration of the state estimator and the source control algorithms.

  19. Power system monitoring and source control of the Space Station Freedom dc-power system testbed

    NASA Technical Reports Server (NTRS)

    Kimnach, Greg L.; Baez, Anastacio N.

    1992-01-01

    Unlike a terrestrial electric utility which can purchase power from a neighboring utility, the Space Station Freedom (SSF) has strictly limited energy resources; as a result, source control, system monitoring, system protection, and load management are essential to the safe and efficient operation of the SSF Electric Power System (EPS). These functions are being evaluated in the dc Power Management and Distribution (PMAD) Testbed which NASA LeRC has developed at the Power System Facility (PSF) located in Cleveland, Ohio. The testbed is an ideal platform to develop, integrate, and verify power system monitoring and control algorithms. State Estimation (SE) is a monitoring tool used extensively in terrestrial electric utilities to ensure safe power system operation. It uses redundant system information to calculate the actual state of the EPS, to isolate faulty sensors, to determine source operating points, to verify faults detected by subsidiary controllers, and to identify high impedance faults. Source control and monitoring safeguard the power generation and storage subsystems and ensure that the power system operates within safe limits while satisfying user demands with minimal interruptions. System monitoring functions, in coordination with hardware implemented schemes, provide for a complete fault protection system. The objective of this paper is to overview the development and integration of the state estimator and the source control algorithms.

  20. Optimized efficiency of all-electric ships by dc hybrid power systems

    NASA Astrophysics Data System (ADS)

    Zahedi, Bijan; Norum, Lars E.; Ludvigsen, Kristine B.

    2014-06-01

    Hybrid power systems with dc distribution are being considered for commercial marine vessels to comply with new stringent environmental regulations, and to achieve higher fuel economy. In this paper, detailed efficiency analysis of a shipboard dc hybrid power system is carried out. An optimization algorithm is proposed to minimize fuel consumption under various loading conditions. The studied system includes diesel engines, synchronous generator-rectifier units, a full-bridge bidirectional converter, and a Li-Ion battery bank as energy storage. In order to evaluate potential fuel saving provided by such a system, an online optimization strategy for fuel consumption is implemented. An Offshore Support Vessel (OSV) is simulated over different operating modes using the online control strategy. The resulted consumed fuel in the simulation is compared to that of a conventional ac power system, and also a dc power system without energy storage. The results show that while the dc system without energy storage provides noticeable fuel saving compared to the conventional ac system, optimal utilization of the energy storage in the dc system results in twice as much fuel saving.

  1. Solid state power systems for DC and RF accelerators

    NASA Astrophysics Data System (ADS)

    Adler, R. J.; Richter-Sand, R. J.

    1999-06-01

    Modern accelerator applications require high average and peak powers—particularly RF accelerators and DC accelerators. In many of these applications, it is possible to replace tubes in the power systems with solid state power supplies. In this paper we outline work which we have performed in developing solid state pulsed and CW pulsed power systems for RF linacs and for DC accelerators. We have built and successfully tested a 125 kV, 2.5 MW peak, 60 kW average pulsed power system which is well suited to driving ion beam linacs. This system is modular, with 3 modules capable of driving a large Klystron. The system has been extensively tested with both resistive and fault loads. This type of power supply promises to be less than half as expensive as a conventional thyratron modulator, with considerably more flexibility in pulse duration. We have also powered our Nested High Voltage (NHV) accelerators with a solid state power supply using IGBTs. This type of supply is suitable for both NHV machines, and other Dynamitron style accelerators. Pulsed burst mode excitation of this type of power supply allows us to maintain 1 MV in the NHV accelerator with less than three hundred watts of idling power.

  2. Maximum Power Point Tracking Controller for Thermoelectric Generators with Peak Gain Control of Boost DC-DC Converters

    NASA Astrophysics Data System (ADS)

    Park, Jungyong; Kim, Shiho

    2012-06-01

    An analog maximum power point tracking (MPPT) circuit for a thermoelectric generator (TEG) is proposed. We show that the peak point of the voltage conversion gain of a boost DC-DC converter with an input voltage source having an internal resistor is the maximum power point of the TEG. The key characteristic of the proposed MPPT controller is that the duty ratio of the input clock pulse to the boost DC-DC converter shifts toward the maximum power point of the TEG by seeking the peak gain point of the boost DC-DC converters. The proposed MPPT technique provides a simple and useful analog MPPT solution, without employing digital microcontroller units.

  3. An Interleaved Reduced-Component-Count Multivoltage Bus DC/DC Converter for Fuel Cell Powered Electric Vehicle Applications

    SciTech Connect

    Tang, Lixin; Su, Gui-Jia

    2008-01-01

    An interleaved reduced-component-count dc/dc converter is proposed for power management in fuel cell powered vehicles with a multivoltage electric net. The converter is based on a simplified topology and can handle more power with less ripple current, therefore reducing the capacitor requirements, making it more suited for fuel cell powered vehicles in the near future. A prototype rated at 4.3 kW was built and tested to verify the proposed topology.

  4. The 25 kW resonant dc/dc power converter

    NASA Technical Reports Server (NTRS)

    Robson, R. R.

    1983-01-01

    The feasibility of processing 25-kW of power with a single, transistorized, series resonant converter stage was demonstrated by the successful design, development, fabrication, and testing of such a device which employs four Westinghouse D7ST transistors in a full-bridge configuration and operates from a 250-to-350 Vdc input bus. The unit has an overall worst-case efficiency of 93.5% at its full rated output of 1000 V and 25 A dc. A solid-state dc input circuit breaker and output-transient-current limiters are included in and integrated into the design. Full circuit details of the converter are presented along with the test data.

  5. Inverse dual converter (IDC) for high power dc-dc applications

    NASA Astrophysics Data System (ADS)

    Ehsani, M.; Husain, I.; Bilgic, M. O.

    The inverse dual converter (IDC), suitable for high-power dc-dc conversion applications, is presented. The IDC is a voltage source converter with an ac link and has been derived from an inductor converter bridge. This capacitor commutated converter is capable of continuous voltage step-up or step-down control over a wide range without the need of a transformer. In addition to high-frequency switching the converter is characterized by soft switching techniques, reducing constraints on the ratings of the switches. The average model developed with the help of gyrator theory provides sufficient information for control strategies and design considerations. The results of gyrator modeling and computer simulation are compared with experimental results obtained from a prototype IDC.

  6. DC-link approach to constant-frequency aircraft power

    NASA Technical Reports Server (NTRS)

    Yorksi, D. S.

    1983-01-01

    This paper discusses a hybrid high-power aircraft electrical system that has very difficult and complex operating requirements. Many issues raised in selecting an approach for this application are similar to those that must eventually be addressed for a large all-electric aircraft. The requirements for this specific system are reviewed, a solution for those requirements is proposed, and some explanation is provided for the choice. Because the system requires a substantial amount of 400-Hz power, a dc-link system was selected to provide that power.

  7. A Reduced-Part, Triple-Voltage DC-DC Converter for EV/HEV Power Management

    SciTech Connect

    Su, Gui-Jia; Tang, Lixin

    2009-01-01

    Electrical power systems in future hybrid and fuel cell vehicles may consist of three voltage nets: 14 V, 42 V, and high voltage (>200 V) buses. A soft-switched, bidirectional dc-dc converter that uses only four switches was proposed for interconnecting the three nets. This paper presents a reduced-part dc-dc converter, which decreases the converter cost while retaining all the favorable features of the original topology. Experimental data are included to verify a simple power flow control scheme.

  8. High power density dc-to-dc converters for aerospace applications

    NASA Technical Reports Server (NTRS)

    Divan, Deepakraj M.

    1990-01-01

    Three dc-to-dc converter topologies aimed at high-power high-frequency applications are introduced. Major system parasitics, namely, the leakage inductance of the transformer and the device output capacitance are efficiently utilized. Of the three circuits, the single-phase and three-phase versions of the dual active bridge topology demonstrate minimal stresses, better utilization of the transformer, bidirectional, and buck-boost modes of operation. All circuits operate at a constant switching frequency, thus simplifying design of the reactive elements. The power transfer characteristics and soft-switching regions on the Vout-Iout plane are identified. Two coaxial transformers with different cross-sections were built for a rating of 50 kVA. Based on the single-phase dual active bridge topology, a 50 kW, 50 kHz converter operating at an input voltage of 200 Vdc and an output voltage of 1600 Vdc was fabricated. Characteristics of current-fed output make the dual active bridge topologies amenable to paralleling and hence extension to megawatt power levels. Projections to a 1 MW system operating from a 500 Vdc input, at an output voltage of 10 kVdc and a switching frequency of 50 kHz, using MOS-controlled thyristors, coaxially wound transformers operating at three times the present current density with cooling, and multilayer ceramic capacitors, suggests an overall power density of 0.075 to 0.08 kg/kW and an overall efficiency of 96 percent.

  9. Electrodeposited Nanolaminated CoNiFe Cores for Ultracompact DC-DC Power Conversion

    SciTech Connect

    Kim, J; Kim, M; Herrault, F; Park, JY; Allen, MG

    2015-09-01

    Laminated metallic alloy cores (i.e., alternating layers of thin film metallic alloy and insulating material) of appropriate lamination thickness enable suppression of eddy current losses at high frequencies. Magnetic cores comprised of many such laminations yield substantial overall magnetic volume, thereby enabling high-power operation. Previously, we reported nanolaminated permalloy (Ni-80 Fe-20) cores based on a sequential electrodeposition technique, demonstrating negligible eddy current losses at peak flux densities up to 0.5 T and operating at megahertz frequencies. This paper demonstrates improved performance of nanolaminated cores comprising tens to hundreds of layers of 300-500-nm-thick CoNiFe films that exhibit superior magnetic properties (e.g., higher saturation flux density and lower coercivity) than permalloy. Nanolaminated CoNiFe cores can be operated up to a peak flux density of 0.9 T, demonstrating improved power handling capacity and exhibiting 30% reduced volumetric core loss, attributed to lowered hysteresis losses compared to the nanolaminated permalloy core of the same geometry. Operating these cores in a buck dc-dc power converter at a switching frequency of 1 MHz, the nanolaminated CoNiFe cores achieved a conversion efficiency exceeding 90% at output power levels up to 7 W, compared to an achieved permalloy core conversion efficiency below 86% at 6 W.

  10. Research study on multi-KW DC distribution system

    NASA Technical Reports Server (NTRS)

    Berkery, E. A.

    1975-01-01

    Power distribution system noise and transient stress on switchgear in large space vehicle power systems were investigated in terms of the effect of flight designs of long power distribution cables on load interface EMI requirements. A fifty meter cable pair was simulated to study interactions between the cable, load, and power source terminations. Power system noise characteristics were evaluated based on current spacecraft data, interface hardware filter designs, and power cable parameters. Parametric approaches were defined for evaluating switching transients at various distribution voltage levels. It is concluded that the state-of-the-art semiconductor switches represent a viable approach toward the implementation of power system design with distribution voltages of 120 VDC or less. The interface definition and design for the bus control unit was updated to be consistent with the established requirements.

  11. Automated power distribution system hardware. [for space station power supplies

    NASA Technical Reports Server (NTRS)

    Anderson, Paul M.; Martin, James A.; Thomason, Cindy

    1989-01-01

    An automated power distribution system testbed for the space station common modules has been developed. It incorporates automated control and monitoring of a utility-type power system. Automated power system switchgear, control and sensor hardware requirements, hardware design, test results, and potential applications are discussed. The system is designed so that the automated control and monitoring of the power system is compatible with both a 208-V, 20-kHz single-phase AC system and a high-voltage (120 to 150 V) DC system.

  12. Industrial power distribution

    SciTech Connect

    Sorrells, M.A.

    1990-01-01

    This paper is a broad overview of industrial power distribution. Primary focus will be on selection of the various low voltage components to achieve the end product. Emphasis will be on the use of national standards to ensure a safe and well designed installation.

  13. dc-to-ac power converter for fuel cell system

    SciTech Connect

    Kawabata, T.; Asaeda, T.; Hamasaki, Y.; Yutani, T.

    1983-10-01

    As the interface between fuel cells and the utility line, a self-commutated inverter is preferred to a line-commutated inverter because of its easy controllability. Using the gate turn off (GTO) thyristors, this inverter can have high efficiency and simple circuit configurations. This paper describes the design features and test results of the dc-to-ac power converter, which is principally composed of four-phase transistor chopper and 12-pulse GTO inverter, for a 50kW experimental fuel cell power system. Furthermore, new GTO inverter which improves the circuit efficiency is presented. Special emphasis is placed on a detailed analysis and evaluation of this GTO inverter.

  14. Hardwired Control Changes For NSTX DC Power Feeds

    SciTech Connect

    Ramakrishnan, S.

    2013-06-28

    The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at Princeton Plasma Physics Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. The original TFTR Hardwired Control System (HCS) with electromechanical relays was used for NSTX DC Power loop control and protection during NSTX operations. As part of the NSTX Upgrade, the HCS is being changed to a PLC-based system with the same control logic. This paper gives a description of the changeover to the new PLC-based system __________________________________________________

  15. A Low-Power Asynchronous Step-Down DC-DC Converter for Implantable Devices.

    PubMed

    Al-Terkawi Hasib, Omar; Sawan, M; Savaria, Y

    2011-06-01

    In this paper, we present a fully integrated asynchronous step-down switched capacitor dc-dc conversion structure suitable for supporting ultra-low-power circuits commonly found in biomedical implants. The proposed converter uses a fully digital asynchronous state machine as the heart of the control circuitry to generate the drive signals. To minimize the switching losses, the asynchronous controller scales the switching frequency of the drive signals according to the loading conditions. It also turns on additional parallel switches when needed and has a backup synchronous drive mode. This circuit regulates load voltages from 300 mV to 1.1 V derived from a 1.2-V input voltage. A total of 350 pF on-chip capacitance was implemented to support a maximum of 230-μ W load power, while providing efficiency up to 80%. The circuit validating the proposed concepts was fabricated in 0.13- μm complementary metal-oxide semiconductor technology. Experimental test results confirm the expected functionality and performance of the proposed circuit. PMID:23851480

  16. A Low-Power Asynchronous Step-Down DC-DC Converter for Implantable Devices.

    PubMed

    Al-Terkawi Hasib, Omar; Sawan, M; Savaria, Y

    2011-06-01

    In this paper, we present a fully integrated asynchronous step-down switched capacitor dc-dc conversion structure suitable for supporting ultra-low-power circuits commonly found in biomedical implants. The proposed converter uses a fully digital asynchronous state machine as the heart of the control circuitry to generate the drive signals. To minimize the switching losses, the asynchronous controller scales the switching frequency of the drive signals according to the loading conditions. It also turns on additional parallel switches when needed and has a backup synchronous drive mode. This circuit regulates load voltages from 300 mV to 1.1 V derived from a 1.2-V input voltage. A total of 350 pF on-chip capacitance was implemented to support a maximum of 230-μ W load power, while providing efficiency up to 80%. The circuit validating the proposed concepts was fabricated in 0.13- μm complementary metal-oxide semiconductor technology. Experimental test results confirm the expected functionality and performance of the proposed circuit.

  17. Auxiliary quasi-resonant dc tank electrical power converter

    DOEpatents

    Peng, Fang Z.

    2006-10-24

    An auxiliary quasi-resonant dc tank (AQRDCT) power converter with fast current charging, voltage balancing (or charging), and voltage clamping circuits is provided for achieving soft-switched power conversion. The present invention is an improvement of the invention taught in U.S. Pat. No. 6,111,770, herein incorporated by reference. The present invention provides faster current charging to the resonant inductor, thus minimizing delay time of the pulse width modulation (PWM) due to the soft-switching process. The new AQRDCT converter includes three tank capacitors or power supplies to achieve the faster current charging and minimize the soft-switching time delay. The new AQRDCT converter further includes a voltage balancing circuit to charge and discharge the three tank capacitors so that additional isolated power supplies from the utility line are not needed. A voltage clamping circuit is also included for clamping voltage surge due to the reverse recovery of diodes.

  18. Generating expansion model incorporating compact DC power flow equations

    SciTech Connect

    Nderitu, D.G.; Sparrow, F.T.; Yu, Z.

    1998-12-31

    This paper presents a compact method of incorporating the spatial dimension into the generation expansion problem. Compact DC power flow equations are used to provide real-power flow coordination equations. Using these equations the marginal contribution of a generator to th total system loss is formulated as a function of that generator`s output. Incorporating these flow equations directly into the MIP formulation of the generator expansion problem results in a model that captures a generator`s true net marginal cost, one that includes both the cost of generation and the cost of transport. This method contrasts with other methods that iterate between a generator expansion model and an optimal power flow model. The proposed model is very compact and has very good convergence performance. A case study with data from Kenya is used to provide a practical application to the model.

  19. Controller for a High-Power, Brushless dc Motor

    NASA Technical Reports Server (NTRS)

    Fleming, David J.; Makdad, Terence A.

    1987-01-01

    Driving and braking torques controllable. Control circuit operates 7-kW, 45-lb-ft (61-N-m), three-phase, brushless dc motor in both motor and generator modes. In motor modes, energy from power source is pulse-width modulated to motor through modified "H-bridge" circuit, in generator mode, energy from motor is pulse-width modulated into bank of load resistors to provide variable braking torques. Circuit provides high-resolution torque control in both directions over wide range of speeds and torques. Tested successfully at bus voltages up to 200 Vdc and currents up to 45 A.

  20. UPS with input commutation between ac and dc sources of power

    SciTech Connect

    Severinsky, A.J.

    1993-08-31

    An uninterruptible power supply is described, said power supply comprising: AC input terminal means for receiving a first AC voltage from an AC power source; DC input terminal means for receiving a first DC voltage from a DC power source; AC output terminal means for connecting to a load; converter means for converting said first AC voltage to a second DC voltage across electrical charge storage means coupled to said converter means, said second DC voltage being larger than the maximum peak voltage of said first AC voltage and said first DC voltage; switching means coupled to said AC power source and said DC power source for selectively connecting said AC power source or said DC power source to said converter means; inverter means coupled to said electrical charge storage means for receiving said second DC voltage and inverting said second DC voltage to a second AC voltage, said second AC voltage being coupled to said AC output terminal means; and control means coupled to said switching means for controlling the operation of said switching means, said control means operating said switching means to connect said AC power source to said converter means only when said first AC voltage is within a predetermined range and operating to connect said DC power source to said converter means when said first AC voltage is outside of said range.

  1. Automated Power-Distribution System

    NASA Technical Reports Server (NTRS)

    Thomason, Cindy; Anderson, Paul M.; Martin, James A.

    1990-01-01

    Automated power-distribution system monitors and controls electrical power to modules in network. Handles both 208-V, 20-kHz single-phase alternating current and 120- to 150-V direct current. Power distributed to load modules from power-distribution control units (PDCU's) via subsystem distributors. Ring busses carry power to PDCU's from power source. Needs minimal attention. Detects faults and also protects against them. Potential applications include autonomous land vehicles and automated industrial process systems.

  2. Integrated modeling and control of a PEM fuel cell power system with a PWM DC/DC converter

    NASA Astrophysics Data System (ADS)

    Choe, Song-Yul; Lee, Jung-Gi; Ahn, Jong-Woo; Baek, Soo-Hyun

    A fuel cell powered system is regarded as a high current and low voltage source. To boost the output voltage of a fuel cell, a DC/DC converter is employed. Since these two systems show different dynamics, they need to be coordinated to meet the demand of a load. This paper proposes models for the two systems with associated controls, which take into account a PEM fuel cell stack with air supply and thermal systems, and a PWM DC/DC converter. The integrated simulation facilitates optimization of the power control strategy, and analyses of interrelated effects between the electric load and the temperature of cell components. In addition, the results show that the proposed power control can coordinate the two sources with improved dynamics and efficiency at a given dynamic load.

  3. Detection of High-impedance Arcing Faults in Radial Distribution DC Systems

    NASA Technical Reports Server (NTRS)

    Gonzalez, Marcelo C.; Button, Robert M.

    2003-01-01

    High voltage, low current arcing faults in DC power systems have been researched at the NASA Glenn Research Center in order to develop a method for detecting these 'hidden faults', in-situ, before damage to cables and components from localized heating can occur. A simple arc generator was built and high-speed and low-speed monitoring of the voltage and current waveforms, respectively, has shown that these high impedance faults produce a significant increase in high frequency content in the DC bus voltage and low frequency content in the DC system current. Based on these observations, an algorithm was developed using a high-speed data acquisition system that was able to accurately detect high impedance arcing events induced in a single-line system based on the frequency content of the DC bus voltage or the system current. Next, a multi-line, radial distribution system was researched to see if the arc location could be determined through the voltage information when multiple 'detectors' are present in the system. It was shown that a small, passive LC filter was sufficient to reliably isolate the fault to a single line in a multi-line distribution system. Of course, no modification is necessary if only the current information is used to locate the arc. However, data shows that it might be necessary to monitor both the system current and bus voltage to improve the chances of detecting and locating high impedance arcing faults

  4. A study of DC-DC converters with MCT's for arcjet power supplies

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.

    1994-01-01

    Many arcjet DC power supplies use PWM full bridge converters with large arrays of parallel FET's. This report investigates an alternative supply using a variable frequency series resonant converter with small arrays of parallel MCT's (metal oxide semiconductor controlled thyristors). The reasons for this approach are to: increase reliability by reducing the number of switching devices; and decrease the surface mounting area of the switching arrays. The variable frequency series resonant approach is used because the relatively slow switching speed of the MCT precludes the use of PWM. The 10 kW converter operated satisfactorily with an efficiency of over 91 percent. Test results indicate this efficiency could be increased further by additional optimization of the series resonant inductor.

  5. SPEAR3 DC MAGNET POWER SUPPLIES - AN OVERVIEW

    SciTech Connect

    de Lira, A

    2004-03-25

    The Stanford Synchrotron Radiation Laboratory (SSRL) has successfully commissioned SPEAR 3, its newly upgraded 3-GeV synchrotron light source. First stored beam occurred December 15, 2003. This paper presents an overview and descriptions of the DC magnet power supplies. These consist of tightly-regulated ({le} 10 ppm) current sources ranging in output from 30 A to 800 A and output power ranging from a few watts to almost 1.0 MW. A total of 226 magnet power supplies are in successful operation. The SPEAR 3 upgrade performance and reliability requirements mandated new power supplies for both the SPEAR 3 storage ring, and for the booster-to-SPEAR 3 (BTS) transport line. A large variety of precise, highly stable current power supplies were needed to fill the diverse magnet needs. Also described are outside procurement aspects, in-house construction, installation, testing, performance and operation of the power supplies. During field testing, special emphasis was made to ensure a critically damped response on the current loop. Frequency spectra measurements were made for reference and future diagnostics.

  6. DC switching regulated power supply for driving an inductive load

    DOEpatents

    Dyer, G.R.

    1983-11-29

    A dc switching regulated power supply for driving an inductive load is provided. The regulator basic circuit is a bridge arrangement of diodes and transistors. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. A dc power supply is connected to the input of the bridge and the output is connected to the load. A servo controller is provided to control the switching rate of the transistors to maintain a desired current to the load. The regulator may be operated in three stages or modes: (1) for current runup in the load, both first and second transistor switch arrays are turned on and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned off, and load current flywheels through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays off, allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load.

  7. Automated Power-Distribution System

    NASA Technical Reports Server (NTRS)

    Ashworth, Barry; Riedesel, Joel; Myers, Chris; Miller, William; Jones, Ellen F.; Freeman, Kenneth; Walsh, Richard; Walls, Bryan K.; Weeks, David J.; Bechtel, Robert T.

    1992-01-01

    Autonomous power-distribution system includes power-control equipment and automation equipment. System automatically schedules connection of power to loads and reconfigures itself when it detects fault. Potential terrestrial applications include optimization of consumption of power in homes, power supplies for autonomous land vehicles and vessels, and power supplies for automated industrial processes.

  8. Use Conditions and Efficiency Measurements of DC Power Optimizers for Photovoltaic Systems: Preprint

    SciTech Connect

    Deline, C.; MacAlpine, S.

    2013-10-01

    No consensus standard exists for estimating annual conversion efficiency of DC-DC converters or power optimizers in photovoltaic (PV) applications. The performance benefits of PV power electronics including per-panel DC-DC converters depend in large part on the operating conditions of the PV system, along with the performance characteristics of the power optimizer itself. This work presents acase study of three system configurations that take advantage of the capabilities of DC power optimizers. Measured conversion efficiencies of DC-DC converters are applied to these scenarios to determine the annual weighted operating efficiency. A simplified general method of reporting weighted efficiency is given, based on the California Energy Commission's CEC efficiency rating and severalinput / output voltage ratios. Efficiency measurements of commercial power optimizer products are presented using the new performance metric, along with a description of the limitations of the approach.

  9. AC/DC Power Systems with Applications for future Lunar/Mars base and Crew Exploration Vehicle

    NASA Technical Reports Server (NTRS)

    Chowdhury, Badrul H.

    2005-01-01

    ABSTRACT The Power Systems branch at JSC faces a number of complex issues as it readies itself for the President's initiative on future space exploration beyond low earth orbit. Some of these preliminary issues - those dealing with electric power generation and distribution on board Mars-bound vehicle and that on Lunar and Martian surface may be summarized as follows: Type of prime mover - Because solar power may not be readily available on parts of the Lunar/Mars surface and also during the long duration flight to Mars, the primary source of power will most likely be nuclear power (Uranium fuel rods) with a secondary source of fuel cell (Hydrogen supply). The electric power generation source - With nuclear power being the main prime mover, the electric power generation source will most likely be an ac generator at a yet to be determined frequency. Thus, a critical issue is whether the generator should generate at constant or variable frequency. This will decide what type of generator to use - whether it is a synchronous machine, an asynchronous induction machine or a switched reluctance machine. The type of power distribution system - the distribution frequency, number of wires (3- wire, 4-wire or higher), and ac/dc hybridization. Building redundancy and fault tolerance in the generation and distribution sub-systems so that the system is safe; provides 100% availability to critical loads; continues to operate even with faulted sub-systems; and requires minimal maintenance. This report descril_es results of a summer faculty fellowship spent in the Power Systems Branch with the specific aim of investigating some of the lessons learned in electric power generation and usage from the terrestrial power systems industry, the aerospace industry as well as NASA's on-going missions so as to recommend novel surface and vehicle-based power systems architectures in support of future space exploration initiatives. A hybrid ac/dc architecture with source side and load side

  10. A brief review of models of DC-DC power electronic converters for analysis of their stability

    NASA Astrophysics Data System (ADS)

    Siewniak, Piotr; Grzesik, Bogusław

    2014-10-01

    A brief review of models of DC-DC power electronic converters (PECs) is presented in this paper. It contains the most popular, continuous-time and discrete-time models used for PEC simulation, design, stability analysis and other applications. Both large-signal and small-signal models are considered. Special attention is paid to models that are used in practice for the analysis of the global and local stability of PECs.

  11. An efficient switch-mode power supply using an AC-DC interleaved boost converter and a DC-DC full-bridge topology

    NASA Astrophysics Data System (ADS)

    Lessa Tofoli, Fernando; Gallo, Carlos Alberto

    2011-04-01

    This work presents the conception and analysis of a switch-mode power supply with desirable characteristics of high power factor, low harmonic distortion, regulated output voltage, and high efficiency. An interleaved boost converter associated with a nondissipative snubber is used as a preregulator stage. Additionally, a soft switching full-bridge converter is chosen as DC-DC stage. The combination of both topologies results in the proposed switch-mode power supply. Theoretical background on each one of the converters is presented and analytical results are discussed in order to validate the proposal.

  12. The dc power control for a liquid-fed resistojet

    NASA Technical Reports Server (NTRS)

    Gruber, Robert P.

    1988-01-01

    A simple breadboard power controller was designed and demonstrated for a new liquid-fed water resistojet. The 1-piece laboratory model thruster has an integrated vaporizer/superheater using a single heating element. Heater temperature was maintained at or near a preset reference value with the closed loop controller providing pulse width modulated (PWM) dc power into the thruster heater. A combined thruster, temperature readout, PWM transfer function was experimentally determined. This transfer function was used to design a proportional plus integral controller that demonstrated zero steady state error, conservative stability margins and adequate transient response to step changes in propellant flow rate, input voltage and temperature reference. Initial turn-on temperature overshoot from room temperature to a 650 C setpoint was 80 C. In addition, EMI was alleviated by reducing heater dI/dt and dV/dt using a simple diode-inductor-capacitor network. Based on limited initial tests, thruster preheat with no propellant flow was necessary to achieve stable system operation during startup. Breadboard power efficiency was 99 percent at 1 kW, and component mass was 0.4 kg excluding the power loss and mass of an input filter required for spacecraft integration.

  13. Patch Network for Power Allocation and Distribution in Smart Materials

    NASA Technical Reports Server (NTRS)

    Golembiewski, Walter T.

    2000-01-01

    The power allocation and distribution (PAD) circuitry is capable of allocating and distributing a single or multiple sources of power over multi-elements of a power user grid system. The purpose of this invention is to allocate and distribute power that is collected by individual patch rectennas to a region of specific power-user devices, such as actuators. The patch rectenna converts microwave power into DC power. Then this DC power is used to drive actuator devices. However, the power from patch rectennas is not sufficient to drive actuators unless all the collected power is effectively used to drive another group by allocation and distribution. The power allocation and distribution (PAD) circuitry solves the shortfall of power for devices in a large array. The PAD concept is based on the networked power control in which power collected over the whole array of rectennas is allocated to a sub domain where a group of devices is required to be activated for operation. Then the allocated power is distributed to individual element of power-devices in the sub domain according to a selected run-mode.

  14. Development of battery powered 100 kV dc power supply

    NASA Astrophysics Data System (ADS)

    Verma, Rishi; Shyam, A.; Nair, Lakshmi

    2006-10-01

    The increased interest in pulsed power field applications has generated the need for development of compact and remotely operated chargers driven by rechargeable batteries. With this objective, a compact and portable dc to dc Converter has been developed which has an output rating of 100kV, 0.4mA. The high voltage generation scheme uses a hybrid approach. The overall idea behind implementation of hybrid concept is to optimize voltage upliftment with suitable techniques for maximizing power delivered per unit volume. The proposed converter provides this feature and uses flyback converter in association with Cockcroft-Walton Multiplier [M. Jullian, Cockcroft-Walton Multiplier Optimum Design Guide V2.0, August 2005 (http//www.blazelabes.com)] for the generation of 100kV dc from 12V dc source, i.e., normal battery. In the first stage 12V dc is modulated/chopped into series of high frequency pulses by pulse width modulator and then increased in level up to 16kVpp by step up flyback transformer. Further by using n stage half wave series Cockcroft-Walton multiplier the voltage is stepped up to the level of 100kV. As switching device, state of the art metal-oxide-semiconductor field-effect transistor has been used. The obtained voltage multiplier cascade efficiency is 82.64%, whereas overall power conversion efficiency of the charging power supply is 85.47%. The control unit has been fiber optically isolated from high voltage unit due to safety consideration. The presented article explores complete design and development approach of compact and portable 100kV dc power supply which can be used for a variety of applications such as x-ray generation, ion implantation, charge particle acceleration, radio isotope production, etc.

  15. Investigations of DC power supplies with optoelectronic transducers and RF energy converters

    NASA Astrophysics Data System (ADS)

    Guzowski, B.; Gozdur, R.; Bernacki, L.; Lakomski, M.

    2016-04-01

    Fiber Distribution Cabinets (FDC) monitoring systems are increasingly popular. However it is difficult to realize such system in passive FDC, due to lack of source of power supply. In this paper investigation of four different DC power supplies with optoelectronic transducers is described. Two converters: photovoltaic power converter and PIN photodiode can convert the light transmitted through the optical fiber to electric energy. Solar cell and antenna RF-PCB are also tested. Results presented in this paper clearly demonstrate that it is possible to build monitoring system in passive FDC. During the tests maximum obtained output power was 11 mW. However all converters provided enough power to excite 32-bit microcontroller with ARM-cores and digital thermometer.

  16. Low-to-Medium Power Single Chip Digital Controlled DC-DC Regulator for Point-of-Load Applications

    NASA Technical Reports Server (NTRS)

    Adell, Philippe C. (Inventor); Bakkaloglu, Bertan (Inventor); Vermeire, Bert (Inventor); Liu, Tao (Inventor)

    2015-01-01

    A DC-DC converter for generating a DC output voltage includes: a digitally controlled pulse width modulator (DPWM) for controlling a switching power stage to supply a varying voltage to an inductor; and a digital voltage feedback circuit for controlling the DPWM in accordance with a feedback voltage corresponding to the DC output voltage, the digital voltage feedback circuit including: a first voltage controlled oscillator for converting the feedback voltage into a first frequency signal and to supply the first frequency signal to a first frequency discriminator; a second voltage controlled oscillator for converting a reference voltage into a second frequency signal and to supply the second frequency signal to a second frequency discriminator; a digital comparator for comparing digital outputs of the first and second frequency discriminators and for outputting a digital feedback signal; and a controller for controlling the DPWM in accordance with the digital feedback signal.

  17. ASDTIC control and standardized interface circuits applied to buck, parallel and buck-boost dc to dc power converters

    NASA Technical Reports Server (NTRS)

    Schoenfeld, A. D.; Yu, Y.

    1973-01-01

    Versatile standardized pulse modulation nondissipatively regulated control signal processing circuits were applied to three most commonly used dc to dc power converter configurations: (1) the series switching buck-regulator, (2) the pulse modulated parallel inverter, and (3) the buck-boost converter. The unique control concept and the commonality of control functions for all switching regulators have resulted in improved static and dynamic performance and control circuit standardization. New power-circuit technology was also applied to enhance reliability and to achieve optimum weight and efficiency.

  18. Circuit and Method for Communication Over DC Power Line

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J.; Prokop, Norman F.

    2007-01-01

    A circuit and method for transmitting and receiving on-off-keyed (OOK) signals with fractional signal-to-noise ratios uses available high-temperature silicon- on-insulator (SOI) components to move computational, sensing, and actuation abilities closer to high-temperature or high-ionizing radiation environments such as vehicle engine compartments, deep-hole drilling environments, industrial control and monitoring of processes like smelting, and operations near nuclear reactors and in space. This device allows for the networking of multiple, like nodes to each other and to a central processor. It can do this with nothing more than the already in-situ power wiring of the system. The device s microprocessor allows it to make intelligent decisions within the vehicle operational loop and to effect control outputs to its associated actuators. The figure illustrates how each node converts digital serial data to OOK 18-kHz in transmit mode and vice-versa in receive mode; though operations at lower frequencies or up to a megahertz are within reason using this method and these parts. This innovation s technique modulates a DC power bus with millivolt-level signals through a MOSFET (metal oxide semiconductor field effect transistor) and resistor by OOK. It receives and demodulates this signal from the DC power bus through capacitive coupling at high temperature and in high ionizing radiation environments. The demodulation of the OOK signal is accomplished by using an asynchronous quadrature detection technique realized by a quasi-discrete Fourier transform through use of the quadrature components (0 and 90 phases) of the carrier frequency as generated by the microcontroller and as a function of the selected crystal frequency driving its oscillator. The detected signal is rectified using an absolute-value circuit containing no diodes (diodes being non-operational at high temperatures), and only operational amplifiers. The absolute values of the two phases of the received signal

  19. DC switching regulated power supply for driving an inductive load

    DOEpatents

    Dyer, George R.

    1986-01-01

    A power supply for driving an inductive load current from a dc power supply hrough a regulator circuit including a bridge arrangement of diodes and switching transistors controlled by a servo controller which regulates switching in response to the load current to maintain a selected load current. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. The regulator may be operated in three "stages" or modes: (1) For current runup in the load, both first and second transistor switch arrays are turned "on" and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned "off", and load current "flywheels" through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays "off", allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load. The three operating states are controlled automatically by the controller.

  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. Wind-powered asynchronous AC/DC/AC converter system. [for electric power supply regulation

    NASA Technical Reports Server (NTRS)

    Reitan, D. K.

    1973-01-01

    Two asynchronous ac/dc/ac systems are modelled that utilize wind power to drive a variable or constant hertz alternator. The first system employs a high power 60-hertz inverter tie to the large backup supply of the power company to either supplement them from wind energy, storage, or from a combination of both at a preset desired current; rectifier and inverter are identical and operate in either mode depending on the silicon control rectifier firing angle. The second system employs the same rectification but from a 60-hertz alternator arrangement; it provides mainly dc output, some sinusoidal 60-hertz from the wind bus and some high harmonic content 60-hertz from an 800-watt inverter.

  2. Optical power distribution system

    SciTech Connect

    Lalmond, R.G.

    1987-09-08

    This patent describes an apparatus for supplying electrical power to electrical components mounted on a circuit board. It consists of: a printed circuit board; electrical components mounted on the printed circuit board; electrically powered sources of optical energy; photovoltaic cell arrays; each photovoltaic cell array being mounted on a corresponding one of the electrical components to provide electrical power to the electrical component on which it is mounted; and means for coupling the optical energy from the electrically powered sources of optical energy to the photovoltaic cell arrays.

  3. A controller resetting strategy for the stabilization of DC-to-DC power converters towards non-minimum phase equilibria

    SciTech Connect

    Llanes-Santiago, O.; Sira-Ramirez, H.

    1994-12-31

    A feedback resetting strategy, exercised on the output of a purposely designed unstable dynamical feedback controller, is shown to yield a robust, and efficient, output voltage stabilization of nonlinear average models of DC-to-DC Power Converters around any non-minimum phase equilibrium point of the system. The technique guarantees, in an average sense, an asymptotically stable behavior of the controlled converter state variables towards their required equilibrium values, while the unstable dynamical compensator output is forcefully kept bounded within an arbitrarily small neighborhood of the required controller operating point.

  4. Distributed Space Solar Power

    NASA Technical Reports Server (NTRS)

    Fork, Richard L.

    2001-01-01

    The objective was to assess the feasibility of safely collecting solar power at geostationary orbit and delivering it to earth. A strategy which could harness a small fraction of the millions of gigawatts of sunlight passing near earth could adequately supply the power needs of earth and those of space exploration far into the future. Light collected and enhanced both spatially and temporally in space and beamed to earth provides probably the only practical means of safe and efficient delivery of this space solar power to earth. In particular, we analyzed the feasibility of delivering power to sites on earth at a comparable intensity, after conversion to a usable form, to existing power needs. Two major obstacles in the delivery of space solar power to earth are safety and the development of a source suitable for space. We focused our approach on: (1) identifying system requirements and designing a strategy satisfying current eye and skin safety requirements; and (2) identifying a concept for a potential space-based source for producing the enhanced light.

  5. Reactive Power from Distributed Energy

    SciTech Connect

    Kueck, John; Kirby, Brendan; Rizy, Tom; Li, Fangxing; Fall, Ndeye

    2006-12-15

    Distributed energy is an attractive option for solving reactive power and distribution system voltage problems because of its proximity to load. But the cost of retrofitting DE devices to absorb or produce reactive power needs to be reduced. There also needs to be a market mechanism in place for ISOs, RTOs, and transmission operators to procure reactive power from the customer side of the meter where DE usually resides. (author)

  6. Power Quality Improvement in Bridgeless Ac-Dc Converter Based Multi-output Switched Mode Power Supply

    NASA Astrophysics Data System (ADS)

    Singh, Shihka; Singh, Bhim; Bhuvaneswari, G.; Bist, Vashist

    2014-12-01

    Computer power supplies are required to have multiple isolated regulated dc voltages with low ripple content and high input power factor at the utility interface. A dc-dc converter is used for obtaining these isolated multi-output dc voltages with excellent regulation. In this paper, a non-isolated ac-dc converter is proposed as the first stage converter to obtain a regulated dc output rather than using a simple uncontrolled diode bridge rectifier at the front end. A dc-dc converter is used at the second stage that has a high frequency transformer with multiple secondary windings to obtain different dc voltage levels at the output. The proposed bridgeless converter based power supply is designed using fundamental design equations, and different component values are calculated. Extensive simulations are carried out to demonstrate the improved performance of the proposed bridgeless converter based multi-output computer power supply at varying source voltages and load conditions. Experimental validation of the power supply is carried on a developed hardware prototype, and the test results are compared with the simulated performance for design verification.

  7. Power ultrasound interaction with DC atmospheric pressure electrical discharge.

    PubMed

    Bálek, Rudolf; Pekárek, Stanislav; Bartáková, Zuzana

    2006-12-22

    The effect of power ultrasound application on DC hollow needle to plate atmospheric pressure electrical discharge enhanced by the flow of air through the needle electrode was studied experimentally. It was found that applying ultrasound increases discharge volume. In this volume take place plasmachemical processes, used in important ecological applications such as the production of ozone, VOC decomposition and de-NOx processes enhancement. In our experiments we used a negatively biased needle electrode as a cathode and a perpendicularly placed surface of the ultrasonic resonator--horn--as an anode. To demonstrate the effect of ultrasound waves on electrical discharge photographs of the discharge for the needle to the ultrasonic resonator at distances of 4, 6 and 8mm are shown. By varying the distance between needle and the surface of the transducer, we were able to create the node or the antinode at the region around the tip of the needle, where the ionization processes are effective. In our experimental arrangement the amplitude of acoustic pressure at antinode exceeded 10(4) Pa. The photographs reveal that the diameter of the discharge on the surface of the ultrasonic horn is increased when ultrasound is applied. The increase of discharge volume caused by the application of ultrasound can be explained as a combined effect of the change of the reduced electric field E/n (E is electric field strength and n is the neutral particles density), strong turbulence of the particles in the discharge region caused by quick changes of amplitudes of the standing ultrasonic wave and finally by the boundary layer near the ultrasonic transducer perturbations due to vibrations of the transducer surface.

  8. High-Frequency ac Power-Distribution System

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.; Mildice, James

    1987-01-01

    Loads managed automatically under cycle-by-cycle control. 440-V rms, 20-kHz ac power system developed. System flexible, versatile, and "transparent" to user equipment, while maintaining high efficiency and low weight. Electrical source, from dc to 2,200-Hz ac converted to 440-V rms, 20-kHz, single-phase ac. Power distributed through low-inductance cables. Output power either dc or variable ac. Energy transferred per cycle reduced by factor of 50. Number of parts reduced by factor of about 5 and power loss reduced by two-thirds. Factors result in increased reliability and reduced costs. Used in any power-distribution system requiring high efficiency, high reliability, low weight, and flexibility to handle variety of sources and loads.

  9. Novel DC ring topology and protection system - a comprehensive solution for mega city power grids

    NASA Astrophysics Data System (ADS)

    Haj-Maharsi, Mohamed Yassine

    2009-07-01

    The development of mega cities leads to increased load concentration and brings additional challenges to managing the electrical grid while keeping power available for critical loads. Techniques using FACTS devices are being applied to alleviate power management difficulties and to confine faults in their originating areas in order to limit the risk of cascading failures in the grid. The addition of many FACTS devices often results in control and protection coordination difficulties, power oscillations between connected networks, subsynchronous resonance problems, and torsional interactions with nearby generator units. The most effective solution is obtained when the individual AC subsystems representing sources and loads are decoupled so a fault in a given subsystem is not propagated to another subsystem. This solution can be achieved by the deployment of a DC system where power sources and loads are connected to the DC bus through voltage source converters. For a mega city, this would be conceived as a DC ring feeding multiple loads and connected to remote and local power sources. Unfortunately, the lack of fast DC circuit breakers has been one of the key issues affecting extensive applications of DC systems with common DC buses; a DC fault would discharge all the capacitors of the DC bus and cause delays in system recovery and possibly a wide system collapse. In this research, I provide a comprehensive solution to mega city power grid problems by proposing a DC system topology that enables grid expansions without affecting existing protection settings or changing existing AC breaker ratings. I also propose the means for protecting the DC system by designing a fast DC breaker and developing a control algorithm capable of isolating DC faults without blocking converter stations or depleting DC bus capacitors. My contribution is three folds: (1) I modeled and simulated Shanghai power grid and performed a study to identify short circuit and voltage stability problems

  10. A Cryogenic Dc-Dc Power Converter for a 100 kW Synchronous HTS Generator at Liquid Nitrogen Temperatures

    NASA Astrophysics Data System (ADS)

    Bailey, Wendell; Wen, Hauming; Yang, Yifeng; Forsyth, Andrew; Jia, Chungjiang

    A dc-dc converter has been developed for retrofitting inside the vacuum space of the HTS rotor of a synchronous generator. The heavy copper sections of the current leads used for energising the HTS field winding were replaced by cryogenic power electronics; consisting of the converter and a rotor control unit. The converter board was designed using an H-bridge configuration with two 5A rated wires connecting the cryogenic boards to the stator control board located on the outside of the generator and drawing power from a (5A, 50 V) dc power source. The robustness of converter board was well demonstrated when it was powered up from a cold start at 82K. When charging the field winding with moderate currents (30A), the heat in-leak to the 'cold' rotor core was only 2W. It continued to function down to 74K, surviving several quenches. However, the quench protection function failed when injecting 75A into the field winding, resulting in the burn out of one of the DC-link capacitors. The magnitudes of the critical currents measured with the original current leads were compared to the quench currents, which was defined as the current which triggered quench protection protocol. The difference between the two currents was rather large, (∼20A). However, additional measurements using a single HTS coil in liquid nitrogen found that this reduction should not be so dramatic and in the region of 4A. Our conclusions identified the converter's switching voltage and its operating frequency as two parameters, which could have contributed to lowering the quench current. Magnetic fields and eddy currents are expected to be more prominent the field winding and its impact on the converter also need further investigation.

  11. Microprocessor control of multiple peak power tracking DC/DC converters for use with solar cell arrays

    NASA Technical Reports Server (NTRS)

    Frederick, Martin E. (Inventor); Jermakian, Joel (Inventor)

    1991-01-01

    A method and an apparatus is provided for efficiently controlling the power output of a solar cell array string or a plurality of solar cell array strings to achieve a maximum amount of output power from the strings under varying conditions of use. Maximum power output from a solar array string is achieved through control of a pulse width modulated DC/DC buck converter which transfers power from a solar array to a load or battery bus. The input voltage from the solar array to the converter is controlled by a pulse width modulation duty cycle, which in turn is controlled by a differential signal controller. By periodically adjusting the control voltage up or down by a small amount and comparing the power on the load or bus with that generated at different voltage values a maximum power output voltage may be obtained. The system is totally modular and additional solar array strings may be added to the system simply by adding converter boards to the system and changing some constants in the controller's control routines.

  12. A 1 MW, 100 kV, less than 100 kg space based dc-dc power converter

    NASA Technical Reports Server (NTRS)

    Cooper, J. R.; White, C. W.

    1991-01-01

    A 1 MW dc-dc power converter has been designed which has an input voltage of 5 kV +/-3 percent, an output voltage of 100 kV +/- 0.25 percent, and a run time of 1000 s at full power. The estimated system mass is 83.8 kg, giving a power density of 11.9 kW/kg. The system exceeded the weight goal of 10 kW/kg through the use of innovative components and system concepts. The system volume is approximately 0.1 cu m, and the overall system efficiency is estimated to be 87 percent. Some of the unique system features include a 50-kHz H-bridge inverter using MOS-controlled thyristors as the switching devices, a resonance transformer to step up the voltage, open-cycle cryogenic hydrogen gas cooling, and a nonrigid, inflatable housing which provides on-demand pressurization of the power converter local environment. This system scales very well to higher output powers. The weight of the 10-MW system with the same input and output voltage requirements and overall system configuration is estimated to be 575.3 kg. This gives a power density of 17.4 kW/kg, significantly higher than the 11.9 kW/kg estimated at 1 MW.

  13. Advanced dc motor controller for battery-powered electric vehicles

    NASA Technical Reports Server (NTRS)

    Belsterling, C. A.

    1981-01-01

    A motor generation set is connected to run from the dc source and generate a voltage in the traction motor armature circuit that normally opposes the source voltage. The functional feasibility of the concept is demonstrated with tests on a Proof of Principle System. An analog computer simulation is developed, validated with the results of the tests, applied to predict the performance of a full scale Functional Model dc Controller. The results indicate high efficiencies over wide operating ranges and exceptional recovery of regenerated energy. The new machine integrates both motor and generator on a single two bearing shaft. The control strategy produces a controlled bidirectional plus or minus 48 volts dc output from the generator permitting full control of a 96 volt dc traction motor from a 48 volt battery, was designed to control a 20 hp traction motor. The controller weighs 63.5 kg (140 lb.) and has a peak efficiency of 90% in random driving modes and 96% during the SAE J 227a/D driving cycle.

  14. Fuel Cell/Electric Double Layer Capacitor Hybrid Power Source Using a Multi-port Bidirectional DC-DC Converter

    NASA Astrophysics Data System (ADS)

    Katayama, Noboru; Kogoshi, Sumio

    A fuel cell/electric double layer capacitor hybrid power source using a multi-port bidirectional DC-DC converter has been developed to reduce load variations for the purpose of extending fuel cell life. The proposed converter operates to maintain the fuel cell current, load voltage and bus voltage at constant values with a digital signal processor. The effect of the proposed converter is evaluated. The charging or discharging current of the EDLC rapidly changes along with step loading, and the voltage and current of the fuel cell are maintained at the constant values. Short-time transient responses show that the fuel cell current ripples 0.35 A at 1 A load change in 6 ms.

  15. Design of a -1 MV dc UHV power supply for ITER NBI

    NASA Astrophysics Data System (ADS)

    Watanabe, K.; Yamamoto, M.; Takemoto, J.; Yamashita, Y.; Dairaku, M.; Kashiwagi, M.; Taniguchi, M.; Tobari, H.; Umeda, N.; Sakamoto, K.; Inoue, T.

    2009-05-01

    Procurement of a dc -1 MV power supply system for the ITER neutral beam injector (NBI) is shared by Japan and the EU. The Japan Atomic Energy Agency as the Japan Domestic Agency (JADA) for ITER contributes to the procurement of dc -1 MV ultra-high voltage (UHV) components such as a dc -1 MV generator, a transmission line and a -1 MV insulating transformer for the ITER NBI power supply. The inverter frequency of 150 Hz in the -1 MV power supply and major circuit parameters have been proposed and adopted in the ITER NBI. The dc UHV insulation has been carefully designed since dc long pulse insulation is quite different from conventional ac insulation or dc short pulse systems. A multi-layer insulation structure of the transformer for a long pulse up to 3600 s has been designed with electric field simulation. Based on the simulation the overall dimensions of the dc UHV components have been finalized. A surge energy suppression system is also essential to protect the accelerator from electric breakdowns. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J, which satisfies the design criteria of 50 J in total in the case of breakdown at -1 MV.

  16. Design research on the conductor of 10 kA class HTS DC power cable

    NASA Astrophysics Data System (ADS)

    Zhang, Dong; Dai, Shaotao; Zhang, Fengyuan; Huang, Tianbin; Wang, Yinshun; Lin, Yubao; Teng, Yuping; Zhang, Guomin; Xiao, Liye; Lin, Liangzhen

    2012-12-01

    High temperature superconducting (HTS) DC power cable shows a wide application prospect in the field of power transmission for its nearly lossless and rather high capacity. A 360 m/10 kA HTS DC power cable system, which connects the rectifier output of a substation with the bus bar of an electrolytic aluminium cell, will be put into operation at Henan Zhongfu Industrial Co., Ltd. As one of the items in this project, a 5 m/10 kA HTS DC power cable was developed, which is used to investigate the conductor design, fabrication, current-carrying capacity and stability of the 360 m/10 kA HTS power cable. The HTS DC power cable core consists of five conductor layers wound with spliced Bi-2223 wires with the length of 600 m. The cable core has five layers and 23 conductors in each layer with the outer diameter of 45.42 mm. The superconducting power cable is fabricated and tested. The critical current is about 14.3 kA at 77 K. The superconducting power cable is charged to 10 kA with rate of 10 A/s and operates at steady-state for 30 min. In this paper, the 10 kA HTS DC power cable design, fabrication and test are presented. The experimental research of the performance of spliced superconducting wire and charging, steady-state operating performance of the cable was carried out.

  17. Comprehensive review of high power factor ac-dc boost converters for PFC applications

    NASA Astrophysics Data System (ADS)

    De Castro Pereira, Dênis; Da Silva, Márcio Renato; Mateus Silva, Elder; Lessa Tofoli, Fernando

    2015-08-01

    High power factor rectifiers have been consolidated as an effective solution to improve power quality indices in terms of input power factor correction, reduction in the total harmonic distortion of the input current and also regulated dc voltages. Within this context, this subject has motivated the introduction of numerous converter topologies based on classic dc-dc structures associated with novel control techniques, thus leading to the manufacturing of dedicated integrated circuits that allow high input power factor by adding a front-end stage to switch-mode converters. In particular, boost converters in continuous current mode (CCM) are widely employed since they allow obtaining minimised electromagnetic interference levels. This work is concerned with a literature review involving relevant ac-dc single-phase boost-based topologies with high input power factor. The evolution of aspects regarding the conventional boost converter is shown in terms of improved characteristics inherent to other ac-dc boost converters. Additionally, the work intends to be a fast and concise reference to single-phase ac-dc boost converters operating in CCM for engineers, researchers and experts in the field of power electronics by properly analysing and comparing the aforementioned rectifiers.

  18. Microwave Driven Actuators Power Allocation and Distribution

    NASA Technical Reports Server (NTRS)

    Forbes, Timothy; Song, Kyo D.

    2000-01-01

    Design, fabrication and test of a power allocation and distribution (PAD) network for microwave driven actuators is presented in this paper. Development of a circuit that would collect power from a rectenna array amplify and distribute the power to actuators was designed and fabricated for space application in an actuator array driven by a microwave. A P-SPICE model was constructed initially for data reduction purposes, and was followed by a working real-world model. A voltage up - converter (VUC) is used to amplify the voltage from the individual rectenna. The testing yielded a 26:1 voltage amplification ratio with input voltage at 9 volts and a measured output voltage 230VDC. Future work includes the miniaturization of the circuitry, the use of microwave remote control, and voltage amplification technology for each voltage source. The objective of this work is to develop a model system that will collect DC voltage from an array of rectenna and propagate the voltage to an array of actuators.

  19. Very low noise AC/DC power supply systems for large detector arrays

    NASA Astrophysics Data System (ADS)

    Arnaboldi, C.; Baù, A.; Carniti, P.; Cassina, L.; Giachero, A.; Gotti, C.; Maino, M.; Passerini, A.; Pessina, G.

    2015-12-01

    In this work, we present the first part of the power supply system for the CUORE and LUCIFER arrays of bolometric detectors. For CUORE, it consists of AC/DC commercial power supplies (0-60 V output) followed by custom DC/DC modules (48 V input, ±5 V to ±13.5 V outputs). Each module has 3 floating and independently configurable output voltages. In LUCIFER, the AC/DC + DC/DC stages are combined into a commercial medium-power AC/DC source. At the outputs of both setups, we introduced filters with the aim of lowering the noise and to protect the following stages from high voltage spikes that can be generated by the energy stored in the cables after the release of accidental short circuits. Output noise is very low, as required: in the 100 MHz bandwidth the RMS level is about 37 μVRMS (CUORE setup) and 90 μVRMS (LUCIFER setup) at a load of 7 A, with a negligible dependence on the load current. Even more importantly, high frequency switching disturbances are almost completely suppressed. The efficiency of both systems is above 85%. Both systems are completely programmable and monitored via CAN bus (optically coupled).

  20. Design and power management of an offshore medium voltage DC microgrid realized through high voltage power electronics technologies and control

    NASA Astrophysics Data System (ADS)

    Grainger, Brandon Michael

    The growth in the electric power industry's portfolio of Direct Current (DC) based generation and loads have captured the attention of many leading research institutions. Opportunities for using DC based systems have been explored in electric ship design and have been a proven, reliable solution for transmitting bulk power onshore and offshore. To integrate many of the renewable resources into our existing AC grid, a number of power conversions through power electronics are required to condition the equipment for direct connection. Within the power conversion stages, there is always a requirement to convert to or from DC. The AC microgrid is a conceptual solution proposed for integrating various types of renewable generation resources. The fundamental microgrid requirements include the capability of operating in islanding mode and/or grid connected modes. The technical challenges associated with microgrids include (1) operation modes and transitions that comply with IEEE1547 without extensive custom engineering and (2) control architecture and communication. The Medium Voltage DC (MVDC) architecture, explored by the University of Pittsburgh, can be visualized as a special type of DC microgrid. This dissertation is multi-faceted, focused on many design aspects of an offshore DC microgrid. The focal points of the discussion are focused on optimized high power, high frequency magnetic material performance in electric machines, transformers, and DC/DC power converters---all components found within offshore, power system architectures. A new controller design based upon model reference control is proposed and shown to stabilize the electric motor drives (modeled as constant power loads), which serve as the largest power consuming entities in the microgrid. The design and simulation of a state-of-the-art multilevel converter for High Voltage DC (HVDC) is discussed and a component sensitivity analysis on fault current peaks is explored. A power management routine is

  1. Hybrid power system intelligent operation and protection involving distributed architectures and pulsed loads

    NASA Astrophysics Data System (ADS)

    Mohamed, Ahmed

    Efficient and reliable techniques for power delivery and utilization are needed to account for the increased penetration of renewable energy sources in electric power systems. Such methods are also required for current and future demands of plug-in electric vehicles and high-power electronic loads. Distributed control and optimal power network architectures will lead to viable solutions to the energy management issue with high level of reliability and security. This dissertation is aimed at developing and verifying new techniques for distributed control by deploying DC microgrids, involving distributed renewable generation and energy storage, through the operating AC power system. To achieve the findings of this dissertation, an energy system architecture was developed involving AC and DC networks, both with distributed generations and demands. The various components of the DC microgrid were designed and built including DC-DC converters, voltage source inverters (VSI) and AC-DC rectifiers featuring novel designs developed by the candidate. New control techniques were developed and implemented to maximize the operating range of the power conditioning units used for integrating renewable energy into the DC bus. The control and operation of the DC microgrids in the hybrid AC/DC system involve intelligent energy management. Real-time energy management algorithms were developed and experimentally verified. These algorithms are based on intelligent decision-making elements along with an optimization process. This was aimed at enhancing the overall performance of the power system and mitigating the effect of heavy non-linear loads with variable intensity and duration. The developed algorithms were also used for managing the charging/discharging process of plug-in electric vehicle emulators. The protection of the proposed hybrid AC/DC power system was studied. Fault analysis and protection scheme and coordination, in addition to ideas on how to retrofit currently available

  2. Integrated Solar Power Converters: Wafer-Level Sub-Module Integrated DC/DC Converter

    SciTech Connect

    2012-02-09

    Solar ADEPT Project: CU-Boulder is developing advanced power conversion components that can be integrated into individual solar panels to improve energy yields. The solar energy that is absorbed and collected by a solar panel is converted into useable energy for the grid through an electronic component called an inverter. Many large, conventional solar energy systems use one, central inverter to convert energy. CU-Boulder is integrating smaller, microinverters into individual solar panels to improve the efficiency of energy collection. The University’s microinverters rely on electrical components that direct energy at high speeds and ensure that minimal energy is lost during the conversion process—improving the overall efficiency of the power conversion process. CU-Boulder is designing its power conversion devices for use on any type of solar panel.

  3. A Theory of Control for a Class of Electronic Power Processing Systems: Energy-Storage DC-To-DC Converters. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Burns, W. W., III

    1977-01-01

    An analytically derived approach to the control of energy-storage dc-to-dc converters, which enables improved system performance and an extensive understanding of the manner in which this improved performance is accomplished, is presented. The control approach is derived from a state-plane analysis of dc-to-dc converter power stages which enables a graphical visualization of the movement of the system state during both steady state and transient operation. This graphical representation of the behavior of dc-to-dc converter systems yields considerable qualitative insight into the cause and effect relationships which exist between various commonly used converter control functions and the system performance which results from them.

  4. A novel wireless power and data transmission AC to DC converter for an implantable device.

    PubMed

    Liu, Jhao-Yan; Tang, Kea-Tiong

    2013-01-01

    This article presents a novel AC to DC converter implemented by standard CMOS technology, applied for wireless power transmission. This circuit combines the functions of the rectifier and DC to DC converter, rather than using the rectifier to convert AC to DC and then supplying the required voltage with regulator as in the transitional method. This modification can reduce the power consumption and the area of the circuit. This circuit also transfers the loading condition back to the external circuit by the load shift keying(LSK), determining if the input power is not enough or excessive, which increases the efficiency of the total system. The AC to DC converter is fabricated with the TSMC 90nm CMOS process. The circuit area is 0.071mm(2). The circuit can produce a 1V DC voltage with maximum output current of 10mA from an AC input ranging from 1.5V to 2V, at 1MHz to 10MHz. PMID:24110077

  5. A novel wireless power and data transmission AC to DC converter for an implantable device.

    PubMed

    Liu, Jhao-Yan; Tang, Kea-Tiong

    2013-01-01

    This article presents a novel AC to DC converter implemented by standard CMOS technology, applied for wireless power transmission. This circuit combines the functions of the rectifier and DC to DC converter, rather than using the rectifier to convert AC to DC and then supplying the required voltage with regulator as in the transitional method. This modification can reduce the power consumption and the area of the circuit. This circuit also transfers the loading condition back to the external circuit by the load shift keying(LSK), determining if the input power is not enough or excessive, which increases the efficiency of the total system. The AC to DC converter is fabricated with the TSMC 90nm CMOS process. The circuit area is 0.071mm(2). The circuit can produce a 1V DC voltage with maximum output current of 10mA from an AC input ranging from 1.5V to 2V, at 1MHz to 10MHz.

  6. Diesel fuel to dc power: Navy & Marine Corps Applications

    SciTech Connect

    Bloomfield, D.P.

    1996-12-31

    During the past year Analytic Power has tested fuel cell stacks and diesel fuel processors for US Navy and Marine Corps applications. The units are 10 kW demonstration power plants. The USN power plant was built to demonstrate the feasibility of diesel fueled PEM fuel cell power plants for 250 kW and 2.5 MW shipboard power systems. We designed and tested a ten cell, 1 kW USMC substack and fuel processor. The complete 10 kW prototype power plant, which has application to both power and hydrogen generation, is now under construction. The USN and USMC fuel cell stacks have been tested on both actual and simulated reformate. Analytic Power has accumulated operating experience with autothermal reforming based fuel processors operating on sulfur bearing diesel fuel, jet fuel, propane and natural gas. We have also completed the design and fabrication of an advanced regenerative ATR for the USMC. One of the significant problems with small fuel processors is heat loss which limits its ability to operate with the high steam to carbon ratios required for coke free high efficiency operation. The new USMC unit specifically addresses these heat transfer issues. The advances in the mill programs have been incorporated into Analytic Power`s commercial units which are now under test.

  7. Development of AC and DC Power Supply Direct Interface Converter

    NASA Astrophysics Data System (ADS)

    Kato, Koji; Itoh, Jun-Ichi

    This paper proposes a novel control method for a direct interface converter for management of the energy flow in either an AC or DC supply. The proposed converter is constructed based on an indirect matrix converter. Therefore a proposed control strategy is based on an indirect control method with a triangular carrier wave. The basic operation of the proposed control method is confirmed by experimental results. In addition, this paper also proposes a commutation error compensation method of an output voltage error and an input current error for an indirect matrix converter. In the proposed method, the output voltage and input current error by the commutation can be compensated at the same time, because the PWM pulse of each switch is directly compensated. The validity of the proposed method is confirmed by experimental results. Those results prove that the proposed compensation method can decrease total harmonic distortion (THD) of the input and output current.

  8. Prospects of long-distance HTS DC power transmission systems

    NASA Astrophysics Data System (ADS)

    Romashov, M. A.; Sytnikov, V. E.; Shakarian, Y. G.; Ivanov, Y. V.

    2014-05-01

    Continual improvement of technologies for the safe use of power resources is a key to sustainable development of a human society. In particular, high-temperature superconductivity (HTS) should be used to meet the growing needs of the electric-power industry. It is known that HTS power cables allow us to increase the level of transmitted energy to several GW at voltage of 66-110 kV. HTS power cables of a coaxial design are almost ideal non-polluting system shielding electromagnetic field. In the present work we have tried to analyze various configurations of HTS power transmission systems, estimate the cable transmission capacitance depending on distance, and characterize reliability and efficiency of the systems.

  9. RF and DC Power Handling Characterization of Thin Film Resistors Embedded on LCP

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Jordan, Jennifer L.; Horst, Stephen; Papapolymerou, John

    2007-01-01

    For the first time, the DC and RF power handling capability of NiCrAlSi thin film resistors on Liquid Crystal Polymer (LCP) is presented. It is shown that there is a maximum power that the resistors can handle without causing degradation of the resistors, and this value is significantly less than the power required for burn out of the resistors. EDAX shows that the resistors fail due to electromigration of Ni and Cr, and migration of C from the LCP.

  10. Design of a high voltage input - output ratio dc-dc converter dedicated to small power fuel cell systems

    NASA Astrophysics Data System (ADS)

    Béthoux, O.; Cathelin, J.

    2010-12-01

    Consuming chemical energy, fuel cells produce simultaneously heat, water and useful electrical power [J.M. Andújar, F. Segura, Renew. Sust. Energy Rev. 13, 2309 (2009)], [J. Larminie, A. Dicks, Fuel Cell Systems Explained, 2nd edn. (John Wiley & Sons, 2003)]. As a matter of fact, the voltage generated by a fuel cell strongly depends on both the load power demand and the operating conditions. Besides, as a result of many design aspects, fuel cells are low voltage and high current electric generators. On the contrary, electric loads are commonly designed for small voltage swing and a high V/I ratio in order to minimize Joule losses. Therefore, electric loads supplied by fuel cells are typically fed by means of an intermediate power voltage regulator. The specifications of such a power converter are to be able to step up the input voltage with a high ratio (a ratio of 10 is a classic situation) and also to work with an excellent efficiency (in order to minimize its size, its weight and its losses) [A. Shahin, B. Huang, J.P. Martin, S. Pierfederici, B. Davat, Energy Conv. Manag. 51, 56 (2010)]. This paper deals with the design of this essential ancillary device. It intends to bring out the best structure for fulfilling this function. Several dc-dc converters with large voltage step-up ratios are introduced. A topology based on a coupled inductor or tapped inductor is closely studied. A detailed modelling is performed with the purpose of providing designing rules. This model is validated with both simulation and implementation. The experimental prototype is based on the following specifications: the fuel cell output voltage ranges from a 50 V open-voltage to a 25 V rated voltage while the load requires a constant 250 V voltage. The studied coupled inductor converter is compared with a classic boost converter commonly used in this voltage elevating application. Even though the voltage regulator faces severe FC specifications, the measured efficiency reaches 96% at the

  11. Anisotropic nanolaminated CoNiFe cores integrated into microinductors for high-frequency dc-dc power conversion

    NASA Astrophysics Data System (ADS)

    Kim, Jooncheol; Kim, Minsoo; Kim, Jung-Kwun; Herrault, Florian; Allen, Mark G.

    2015-11-01

    This paper presents a rectangular, anisotropic nanolaminated CoNiFe core that possesses a magnetically hard axis in the long geometric axis direction. Previously, we have developed nanolaminated cores comprising tens to hundreds of layers of 300-1000 nm thick metallic alloys (i.e. Ni80Fe20 or Co44Ni37Fe19) based on sequential electrodeposition, demonstrating suppressed eddy-current losses at MHz frequencies. In this work, magnetic anisotropy was induced to the nanolaminated CoNiFe cores by applying an external magnetic field (50-100 mT) during CoNiFe film electrodeposition. The fabricated cores comprised tens to hundreds of layers of 500-1000 nm thick CoNiFe laminations that have the hard-axis magnetic property. Packaged in a 22-turn solenoid test inductor, the anisotropic core showed 10% increased effective permeability and 25% reduced core power losses at MHz operation frequency, compared to an isotropic core of the identical geometry. Operating the anisotropic nanolaminated CoNiFe core in a step-down dc-dc converter (15 V input to 5 V output) demonstrated 81% converter efficiency at a switching frequency of 1.1 MHz and output power of 6.5 W. A solenoid microinductor with microfabricated windings integrated with the anisotropic nanolaminated CoNiFe core was fabricated, demonstrating a constant inductance of 600 nH up to 10 MHz and peak quality factor exceeding 20 at 4 MHz. The performance of the microinductor with the anisotropic nanolaminated CoNiFe core is compared with other previously reported microinductors.

  12. Micro-fabricated DC comparison calorimeter for RF power measurement.

    PubMed

    Neji, Bilel; Xu, Jing; Titus, Albert H; Meltzer, Joel

    2014-10-27

    Diode detection and bolometric detection have been widely used to measure radio frequency (RF) power. However, flow calorimeters, in particular micro-fabricated flow calorimeters, have been mostly unexplored as power meters. This paper presents the design, micro-fabrication and characterization of a flow calorimeter. This novel device is capable of measuring power from 100 μW to 200 mW. It has a 50-Ohm load that is heated by the RF source, and the heat is transferred to fluid in a microchannel. The temperature change in the fluid is measured by a thermistor that is connected in one leg of a Wheatstone bridge. The output voltage change of the bridge corresponds to the RF power applied to the load. The microfabricated device measures 25.4 mm × 50.8 mm, excluding the power supplies, microcontroller and fluid pump. Experiments demonstrate that the micro-fabricated sensor has a sensitivity up to 22 × 10⁻³ V/W. The typical resolution of this micro-calorimeter is on the order of 50 μW, and the best resolution is around 10 μW. The effective efficiency is 99.9% from 0−1 GHz and more than 97.5% at frequencies up to 4 GHz. The measured reflection coefficient of the 50-Ohm load and coplanar wave guide is less than −25 dB from 0−2 GHz and less than −16 dB at 2−4 GHz.

  13. Research on design feasibility of high-power light-weight dc-to-dc converters for space power application

    NASA Technical Reports Server (NTRS)

    Wilson, T. G.

    1980-01-01

    The development of 5 kW converters with 100 kHz switching frequencies, consisting of two submodules each capable of 2.5 kW of output power, is discussed. Two semiconductor advances allowed increased power levels. Field effect transistors with ratings of 11 A and 400 V were operated in parallel to provide a converter output power of approximately 2000 W. Secondly, bipolar power switching transistor was operated in conjunction with a turn-off snubber circuit to provide converter output power levels approaching 1000 W. The interrelationships between mass, switching frequency, and efficiency were investigated. Converters were constructed for operation at a maximum output power level of 200 W, and a comparison was made for operation under similar input/output conditions for conversion frequencies of 20 kilohertz and 100 kilohertz. The effects of nondissipative turn-off snubber circuitry were also examined. Finally, a computerized instrumentation system allowing the measurement of pertinent converter operating conditions as well as the recording of converter waveforms is described.

  14. Description of a 20 kilohertz power distribution system

    NASA Technical Reports Server (NTRS)

    Hansen, I. G.

    1986-01-01

    A single phase, 440 VRMS, 20 kHz power distribution system with a regulated sinusoidal wave form is discussed. A single phase power system minimizes the wiring, sensing, and control complexities required in a multi-sourced redundantly distributed power system. The single phase addresses only the distribution links multiphase lower frequency inputs and outputs accommodation techniques are described. While the 440 V operating potential was initially selected for aircraft operating below 50,000 ft, this potential also appears suitable for space power systems. This voltage choice recognizes a reasonable upper limit for semiconductor ratings, yet will direct synthesis of 220 V, 3 power. A 20 kHz operating frequency was selected to be above the range of audibility, minimize the weight of reactive components, yet allow the construction of single power stages of 25 to 30 kW. The regulated sinusoidal distribution system has several advantages. With a regulated voltage, most ac/dc conversions involve rather simple transformer rectifier applications. A sinusoidal distribution system, when used in conjunction with zero crossing switching, represents a minimal source of EMI. The present state of 20 kHz power technology includes computer controls of voltage and/or frequency, low inductance cable, current limiting circuit protection, bi-directional power flow, and motor/generator operating using standard induction machines. A status update and description of each of these items and their significance is presented.

  15. Description of a 20 Kilohertz power distribution system

    NASA Technical Reports Server (NTRS)

    Hansen, I. G.

    1986-01-01

    A single phase, 440 VRMS, 20 kHz power distribution system with a regulated sinusoidal wave form is discussed. A single phase power system minimizes the wiring, sensing, and control complexities required in a multi-sourced redundantly distributed power system. The single phase addresses only the distribution link; mulitphase lower frequency inputs and outputs accommodation techniques are described. While the 440 V operating potential was initially selected for aircraft operating below 50,000 ft, this potential also appears suitable for space power systems. This voltage choice recognizes a reasonable upper limit for semiconductor ratings, yet will direct synthesis of 220 V, 3 power. A 20 kHz operating frequency was selected to be above the range of audibility, minimize the weight of reactive components, yet allow the construction of single power stages of 25 to 30 kW. The regulated sinusoidal distribution system has several advantages. With a regulated voltage, most ac/dc conversions involve rather simple transformer rectifier applications. A sinusoidal distribution system, when used in conjunction with zero crossing switching, represents a minimal source of EMI. The present state of 20 kHz power technology includes computer controls of voltage and/or frequency, low inductance cable, current limiting circuit protection, bi-directional power flow, and motor/generator operating using standard induction machines. A status update and description of each of these items and their significance is presented.

  16. Power management and distribution for the More Electric Aircraft

    SciTech Connect

    Weimer, J.A.

    1995-12-31

    The Air Force More Electric Aircraft (MEA) initiative endorses the notion of driving aircraft subsystems electrically which have traditionally been powered by hydraulic, mechanical, and pneumatic means. Therefore subsystems like hydraulically driven flight control actuators, engine gearbox driven fuel pumps, and bleed air driven environmental control system compressors would be powered electrically via an electrical motor. Studies on two different military fighter aircraft have shown that the MEA concept will provide a significant payoff in aircraft performance and cost. This paper will address many of the technical issues and concerns in developing a fault tolerant, highly reliable electrical power system for the MEA. Additionally, the paper will review the selection of a predominantly 270 Volt DC power system for the MEA and the need to develop additional MEA electrical power system technologies and standards. Many of these issues, concerns and needs are being addressed under the Power Management and Distribution System for More Electric Aircraft (MADMEL) program.

  17. DC uninterrupted power supply having instantaneous switching followed by low impedance switching

    NASA Astrophysics Data System (ADS)

    Hammond, Russell E.; Northup, Robert L.; Shimp, Alan G.

    1991-10-01

    An uninterruptible power supply is provided that incorporates switching circuitry permitting a path for instantaneous DC backup power to be supplied to a voltage-declining primary power supply bus. Once the instantaneous transition is made, battery power is switched to a low impedance path to provide long-term battery power delivery to the bus. At a point where the backup batteries no longer supply useful power to a load, disabling circuitry disconnects the batteries from the load so that excessive draining of the batteries does not result in irreversible battery damage. The uninterruptible power supply of the invention further includes an automatic battery charging circuitry that seeks to maintain the power supply batteries at optimal charge level. To enable an operator to adequately assess battery charge condition, the invention provides battery test circuitry that causes a simulated load to appear at the power supply batteries. Visual representations are then made as to battery status.

  18. Nonlinear control of voltage source converters in AC-DC power system.

    PubMed

    Dash, P K; Nayak, N

    2014-07-01

    This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations.

  19. Nonlinear control of voltage source converters in AC-DC power system.

    PubMed

    Dash, P K; Nayak, N

    2014-07-01

    This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations. PMID:24906895

  20. DC-pass filter design with notch filters superposition for CPW rectenna at low power level

    NASA Astrophysics Data System (ADS)

    Rivière, J.; Douyère, A.; Alicalapa, F.; Luk, J.-D. Lan Sun

    2016-03-01

    In this paper the challenging coplanar waveguide direct current (DC) pass filter is designed, analysed, fabricated and measured. As the ground plane and the conductive line are etched on the same plane, this technology allows the connection of series and shunt elements to the active devices without via holes through the substrate. Indeed, this study presents the first step in the optimization of a complete rectenna in coplanar waveguide (CPW) technology: key element of a radio frequency (RF) energy harvesting system. The measurement of the proposed filter shows good performance in the rejection of F0=2.45 GHz and F1=4.9 GHz. Additionally, a harmonic balance (HB) simulation of the complete rectenna is performed and shows a maximum RF-to-DC conversion efficiency of 37% with the studied DC-pass filter for an input power of 10 µW at 2.45 GHz.

  1. User's manual: Computer-aided design programs for inductor-energy-storage dc-to-dc electronic power converters

    NASA Technical Reports Server (NTRS)

    Huffman, S.

    1977-01-01

    Detailed instructions on the use of two computer-aided-design programs for designing the energy storage inductor for single winding and two winding dc to dc converters are provided. Step by step procedures are given to illustrate the formatting of user input data. The procedures are illustrated by eight sample design problems which include the user input and the computer program output.

  2. Structure of the velocity distribution of sheath-accelerated secondary electrons in an asymmetric RF-dc discharge

    NASA Astrophysics Data System (ADS)

    Khrabrov, Alexander V.; Kaganovich, Igor D.; Ventzek, Peter L. G.; Ranjan, Alok; Chen, Lee

    2015-10-01

    Low-pressure capacitively-coupled discharges with additional dc bias applied to a separate electrode are utilized in plasma-assisted etching for semiconductor device manufacturing. Measurements of the electron velocity distribution function (EVDF) of the flux impinging on the wafer, as well as in the plasma bulk, show a thermal population and additional peaks within a broad range of energies. That range extends from the thermal level up to the value for the ‘ballistic’ peak, corresponding to the bias potential. The non-thermal electron flux has been correlated to alleviating the electron shading effect and providing etch-resistance properties to masking photoresist layers. ‘Middle-energy peak electrons’ at energies of several hundred eV may provide an additional sustaining mechanism for the discharge. These features in the electron velocity (or energy) distribution functions are possibly caused by secondary electrons emitted from the electrodes and interacting with two high-voltage sheaths: a stationary sheath at the dc electrode and an oscillating self-biased sheath at the powered electrode. Since at those energies the mean free path for large-angle scattering (momentum relaxation length) is comparable to, or exceeds the size of the discharge gap, these ‘ballistic’ electrons will not be fully scattered by the background gas as they traverse the inter-electrode space. We have performed test-particle simulations in which the features in the EVDF of electrons impacting the RF electrode are fully resolved at all energies. An analytical model has been developed to predict existence of peaked and step-like structures in the EVDF. Those features can be explained by analyzing the kinematics of electron trajectories in the discharge gap. Step-like structures in the EVDF near the powered electrode appear due to accumulation of electrons emitted from the dc electrode within a portion of the RF cycle, and their subsequent release. Trapping occurs when the RF

  3. Predictive distribution modeling for rare Himalayan medicinal plant Berberis aristata DC.

    PubMed

    Ray, Rajasri; Gururaja, K V; Ramchandra, T V

    2011-11-01

    Predictive distribution modelling of Berberis aristata DC, a rare threatened plant with high medicinal values has been done with an aim to understand its potential distribution zones in Indian Himalayan region. Bioclimatic and topographic variables were used to develop the distribution model with the help of three different algorithms viz. Genetic Algorithm for Rule-set Production (GARP), Bioclim and Maximum entropy (MaxEnt). Maximum entropy has predicted wider potential distribution (10.36%) compared to GARP (4.63%) and Bioclim (2.44%). Validation confirms that these outputs are comparable to the present distribution pattern of the B. aristata. This exercise highlights that this species favours Western Himalaya. However, GARP and MaxEnt's prediction of Eastern Himalayan states (i. e. Arunachal Pradesh, Nagaland and Manipur) are also identified as potential occurrence places require further exploration.

  4. Design and analysis of a high power density and high efficiency permanent magnet DC motor

    NASA Astrophysics Data System (ADS)

    Hwang, C. C.; Chang, J. J.

    2000-01-01

    This paper aims to develop a high power density and high efficiency of motor for electric vehicles. The motor, which is used to replace the traditional engine-driven, is a 5-phase 22-pole square-wave brushless permanent magnet (PM) DC motor. The design and optimization of the motor is done with the aid of electromagnetic field analysis based on the finite element method.

  5. Fuel cells for distributed power generation

    NASA Astrophysics Data System (ADS)

    Tarman, Paul B.

    Deregulation has caused a major change in power distribution in the USA. Large central power stations are being and will continue to be replaced by smaller, distributed power generation sources of less than 20 kW. Fuel cells, specifically molten carbonate fuel cells (MCFCs), are best suited to serve this need. Small turbines cannot achieve the efficiency or environmental friendliness of MCFCs in this power range. This paper discusses the goals of M-C Power Corporation and the advantages of its IMHEX® MCFC technology. M-C Power's factory, demonstration testing program, and its market-entry power plant are also described, as are its commercialization strategy and schedule.

  6. Density distributions of OH, Na, water vapor, and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution

    NASA Astrophysics Data System (ADS)

    Sasaki, Koichi; Ishigame, Hiroaki; Nishiyama, Shusuke

    2015-07-01

    This paper reports the density distributions of OH, Na, water vapor and water mist in atmospheric-pressure dc helium glow plasmas in contact with NaCl solution. The densities of OH, Na and H2O had different spatial distributions, while the Na density had a similar distribution to mist, suggesting that mist is the source of Na in the gas phase. When the flow rate of helium toward the electrolyte surface was increased, the distributions of all the species densities concentrated in the neighboring region to the electrolyte surface more significantly. The densities of all the species were sensitive to the electric polarity of the power supply. In particular, we never detected Na and mist when the electrolyte worked as the anode of the dc discharge. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  7. Simulation and experimental study of DC electric field distribution characteristics of rat hippocampal slices in vitro

    NASA Astrophysics Data System (ADS)

    Zheng, Yu; Dong, Lei; Gao, Yang; Qiu, Qian; Li, Ze-yan; Zhao, Zhe; Chen, Rui-juan; Wang, Hui-quan

    2016-06-01

    Direct current (DC) electric field is a noninvasive neuromodulation tool that can inhibit or facilitate excitability of neurons. Despite its efficacy, the dielectric constant of artificial cerebrospinal fluid and the position and direction of brain slices and other factors can affect the field intensity and distribution acting on the surface of rat hippocampus slices, thus causing errors. In this study, we describe a new analytical method optimized for DC electric fields acting on brain slices, and the design of an external DC electric field stimulator to allow scientific evaluation of brain slices. We investigated parameters regarding the uniformity of electric field distribution and identified the maximal parameters using the finite element method. Then, we selected and simplified slice images using magnetic resonance imaging data and calculated the electric field intensity of the original and simplified models. The electric field simulator induced action potential and excitatory postsynaptic current with intensities of 1, 5, and 10 V/m. This study describes the development of a new electric field stimulator and successfully demonstrates its practicability for scientific evaluation of tissue slices.

  8. Evaluation of electrode configuration and mode of DC power for improvement of electrokinetic soil remediation

    NASA Astrophysics Data System (ADS)

    Kim, Soon-Oh; Lee, Woo Chun; Lee, Sang Woo; Lee, Byung-Tae

    2014-05-01

    Electrokinetic soil remediation is also called electrokinetic soil processing, electroreclamation, and electrochemical decontamination. The electrokinetic technique needs a low-level direct current of the order of mA/cm2 between electrodes to remove contaminants. The electrokinetic technique is one of the most promising remediation processes, and offers high efficiency and time effectiveness in the decontamination of low-permeability soils contaminated with heavy metals, radionuclides, or organic compounds. The significance of this technique is attributed to its low operational cost and potential applicability to a wide range of contaminant types, and these benefits have resulted in the initiation of numerous studies into its use for waste remediation. Electrode configuration is crucial for cost-effectiveness and overall efficacy of the elelectrokinetic processing, particularly in its field implementation. We investigated the effectiveness of various electrode arrays which can be grouped into one-dimensional (1-D) and two-dimensional (2-D) ones. Normally, the DC electricity of full wave has been used to remove contaminants from soils using elelectrokinetic processing. However, application of half-wave DC power can be also taken into account to improve efficacy of the processing, because it generates pulse power and accelerates the migration of contaminants within soils. We empirically evaluated the effect of type of DC electricity on the overall performance of the electrokinetic soil processing. The 1-D configuration with 5 electrode pairs showed the least total electric power, but that consumed in only the soil cell was less in the 2-D arrays than in 1-D ones. Particularly, most of the electric power is likely to be consumed in the electrode compartments, and the electric resistance in the electrode parts should be reduced to save the electric energy cost in the whole processing. In terms of removal efficiencies of 5 heavy metal contaminants, overall efficiency

  9. Fuzzy based power factor improvement strategy for a multiple connected AC-DC converter fed drive

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, N.; Muthiah, Ramaswamy

    2012-01-01

    The main focus of this paper is to design a Fuzzy based control algorithm to realize an improvement in the input power factor of a multiple connected AC-DC converter fed drive system. It incorporates the role of fuzzy inference principles to generate appropriate PWM pulses for the power switches at the second stage of the power module. The philosophy is developed, with a view to reshape the input current phasor and enables it to align with the supply voltage wave in the perspective of improving the input power factor. The closed loop scheme evaluated using MATLAB based simulation exhibits an enhancement in supply power factor over a range of operating loads in addition to illustrating the speed regulating capability of the drive.

  10. Efficient Design in a DC to DC Converter Unit

    NASA Technical Reports Server (NTRS)

    Bruemmer, Joel E.; Williams, Fitch R.; Schmitz, Gregory V.

    2002-01-01

    Space Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is no exception. This paper explores the design methods and tradeoffs that were utilized to accomplish high efficiency in the DDCU. An isolating DC to DC converter was selected for the ISS power system because of requirements for separate primary and secondary grounds and for a well-regulated secondary output voltage derived from a widely varying input voltage. A flyback-current-fed push-pull topology or improved Weinberg circuit was chosen for this converter because of its potential for high efficiency and reliability. To enhance efficiency, a non-dissipative snubber circuit for the very-low-Rds-on Field Effect Transistors (FETs) was utilized, redistributing the energy that could be wasted during the switching cycle of the power FETs. A unique, low-impedance connection system was utilized to improve contact resistance over a bolted connection. For improved consistency in performance and to lower internal wiring inductance and losses a planar bus system is employed. All of these choices contributed to the design of a 6.25 KW regulated dc to dc converter that is 95 percent efficient. The methodology used in the design of this DC to DC Converter Unit may be directly applicable to other systems that require a conservative approach to efficient power conversion and distribution.

  11. Magnification of starting torques of dc motors by maximum power point trackers in photovoltaic systems

    NASA Technical Reports Server (NTRS)

    Appelbaum, J.; Singer, S.

    1989-01-01

    A calculation of the starting torque ratio of permanent magnet, series, and shunt-excited dc motors powered by solar cell arrays is presented for two cases, i.e., with and without a maximum-power-point tracker (MPPT). Defining motor torque magnification by the ratio of the motor torque with an MPPT to the motor torque without an MPPT, a magnification of 3 for the permanent magnet motor and a magnification of 7 for both the series and shunt motors are obtained. The study also shows that all motor types are less sensitive to solar insolation variation in systems including MPPTs as compared to systems without MPPTs.

  12. Multi-Purpose Low Voltage Dual Output DC-DC Converter For 100V Power Bus Telecom Platform

    NASA Astrophysics Data System (ADS)

    Galiana, D.; Mollard, J. M.

    2011-10-01

    The decreasing supply voltages of digital electronic and high speed ADC (Analog to Digital Converter) and DAC (Digital to Analog Converter) require flexible and high current secondary power distribution system. In the frame of the Inmarsat I-XL program, a 12 kW geomobile SatCom satellite, with 100 V regulated power bus, a multi purpose dual output converter was developed for the payload processor as a building block. After a short introduction on the main performance requirements, the baseline architecture is presented. The main drivers of the architecture are reliability, adjustability, radiation tolerant and single event free, volume and mass. The combination of all these constraints highlights the need of significant breakthrough in various domains. Many research results related to packaging and power electronic topics are brought up. These results directly drive the adopted solution presented in the next step followed by a description of the integration of the defined building block in the Inmarsat I-XL payload IP (Integrated Processor). Finally, the main electrical performances such as output ripple and spikes, load step transient and stability are summarized.

  13. A study of some features of ac and dc electric power systems for a space station

    NASA Technical Reports Server (NTRS)

    Hanania, J. I.

    1983-01-01

    This study analyzes certain selected topics in rival dc and high frequency ac electric power systems for a Space Station. The interaction between the Space Station and the plasma environment is analyzed, leading to a limit on the voltage for the solar array and a potential problem with resonance coupling at high frequencies. Certain problems are pointed out in the concept of a rotary transformer, and further development work is indicated in connection with dc circuit switching, special design of a transmission conductor for the ac system, and electric motors. The question of electric shock hazards, particularly at high frequency, is also explored. and a problem with reduced skin resistance and therefore increased hazard with high frequency ac is pointed out. The study concludes with a comparison of the main advantages and disadvantages of the two rival systems, and it is suggested that the choice between the two should be made after further studies and development work are completed.

  14. Magnification of starting torques of dc motors by maximum power point trackers in photovoltaic systems

    NASA Technical Reports Server (NTRS)

    Appelbaum, Joseph; Singer, S.

    1989-01-01

    Direct current (dc) motors are used in terrestrial photovoltaic (PV) systems such as in water-pumping systems for irrigation and water supply. Direct current motors may also be used for space applications. Simple and low weight systems including dc motors may be of special interest in space where the motors are directly coupled to the solar cell array (with no storage). The system will operate only during times when sufficient insolation is available. An important performance characteristic of electric motors is the starting to rated torque ratio. Different types of dc motors have different starting torque ratios. These ratios are dictated by the size of solar cell array, and the developed motor torque may not be sufficient to overcome the load starting torque. By including a maximum power point tracker (MPPT) in the PV system, the starting to rated torque ratio will increase, the amount of which depends on the motor type. The starting torque ratio is calculated for the permanent magnet, series and shunt excited dc motors when powered by solar cell arrays for two cases: with and without MPPT's. Defining a motor torque magnification by the ratio of the motor torque with an MPPT to the motor torque without an MPPT, a magnification of 3 was obtained for the permanent magnet motor and a magnification of 7 for both the series and shunt motors. The effect of the variation of solar insolation on the motor starting torque was covered. All motor types are less sensitive to insolation variation in systems including MPPT's as compared to systems with MPPT's. The analysis of this paper will assist the PV system designed to determine whether or not to include an MPPT in the system for a specific motor type.

  15. Stability of large DC power systems using switching converters, with application to the international space station

    NASA Technical Reports Server (NTRS)

    Manners, B.; Gholdston, E. W.; Karimi, K.; Lee, F. C.; Rajagopalan, J.; Panov, Y.

    1996-01-01

    As space direct current (dc) power systems continue to grow in size, switching power converters are playing an ever larger role in power conditioning and control. When designing a large dc system using power converters of this type, special attention must be placed on the electrical stability of the system and of the individual loads on the system. In the design of the electric power system (EPS) of the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) and its contractor team led by Boeing Defense & Space Group has placed a great deal of emphasis on designing for system and load stability. To achieve this goal, the team has expended considerable effort deriving a dear concept on defining system stability in both a general sense and specifically with respect to the space station. The ISS power system presents numerous challenges with respect to system stability, such as high power, complex sources and undefined loads. To complicate these issues, source and load components have been designed in parallel by three major subcontractors (Boeing, Rocketdyne, and McDonnell Douglas) with interfaces to both sources and loads being designed in different countries (Russia, Japan, Canada, Europe, etc.). These issues, coupled with the program goal of limiting costs, have proven a significant challenge to the program. As a result, the program has derived an impedance specification approach for system stability. This approach is based on the significant relationship between source and load impedances and the effect of this relationship on system stability. This approach is limited in its applicability by the theoretical and practical limits on component designs as presented by each system segment. As a result, the overall approach to system stability implemented by the ISS program consists of specific hardware requirements coupled with extensive system analysis and hardware testing. Following this approach, the ISS program plans to begin

  16. Quantification Approach of Gas Temperate Distribution in Atmospheric Positive DC Glow Discharge Measured by Spectroscopic Imaging

    NASA Astrophysics Data System (ADS)

    Sasamoto, Ryo; Orii, Hideaki; Matsumoto, Takao; Izawa, Yasuji; Nishijima, Kiyoto

    2015-09-01

    In our previous work, a two-dimensional (2D) gas temperature distribution in a positive DC steady-state glow corona was qualitatively measured by spectroscopic imaging. Spectral images of its glow corona were taken using ICCD camera with ultra-narrow band-pass filters, and they were corresponded to the head and tail of a second positive system bands of nitrogen (2PS N2 (0-2)). The qualitative gas temperature was obtained from the emission intensity ratio (I2 Ptail/I2 Phead) between the head and tail of 2PS N2 (0-2). This emission intensity ratio also equals the rotational temperature (TR) , and TR almost equals the gas temperature (TG) in atmospheric pressure. In this work, the qualitative 2D gas temperature distribution was derived from 2D I2 Ptail/I2 Phead plots, and the calibration date of I2 Ptail/I2 Phead for TR was accumulated by investigating the relationship between the spatially average absolute gas temperature (Tav) obtained by single-point spectroscopic measurement and the average value of I2 Ptail/I2 Phead plots. On the basis of the calibration date, a spectroscopically-imaged qualitative 2D I2 Ptail/I2 Phead distribution in a positive DC glow corona was converted to a quantitative 2D image of gas rotational temperature.

  17. An overview of power electronics applications in fuel cell systems: DC and AC converters.

    PubMed

    Ali, M S; Kamarudin, S K; Masdar, M S; Mohamed, A

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter.

  18. An Overview of Power Electronics Applications in Fuel Cell Systems: DC and AC Converters

    PubMed Central

    Ali, M. S.; Kamarudin, S. K.; Masdar, M. S.; Mohamed, A.

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter. PMID:25478581

  19. An overview of power electronics applications in fuel cell systems: DC and AC converters.

    PubMed

    Ali, M S; Kamarudin, S K; Masdar, M S; Mohamed, A

    2014-01-01

    Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter. PMID:25478581

  20. A distributed control approach for power and energy management in a notional shipboard power system

    NASA Astrophysics Data System (ADS)

    Shen, Qunying

    The main goal of this thesis is to present a power control module (PCON) based approach for power and energy management and to examine its control capability in shipboard power system (SPS). The proposed control scheme is implemented in a notional medium voltage direct current (MVDC) integrated power system (IPS) for electric ship. To realize the control functions such as ship mode selection, generator launch schedule, blackout monitoring, and fault ride-through, a PCON based distributed power and energy management system (PEMS) is developed. The control scheme is proposed as two-layer hierarchical architecture with system level on the top as the supervisory control and zonal level on the bottom as the decentralized control, which is based on the zonal distribution characteristic of the notional MVDC IPS that was proposed as one of the approaches for Next Generation Integrated Power System (NGIPS) by Norbert Doerry. Several types of modules with different functionalities are used to derive the control scheme in detail for the notional MVDC IPS. Those modules include the power generation module (PGM) that controls the function of generators, the power conversion module (PCM) that controls the functions of DC/DC or DC/AC converters, etc. Among them, the power control module (PCON) plays a critical role in the PEMS. It is the core of the control process. PCONs in the PEMS interact with all the other modules, such as power propulsion module (PPM), energy storage module (ESM), load shedding module (LSHED), and human machine interface (HMI) to realize the control algorithm in PEMS. The proposed control scheme is implemented in real time using the real time digital simulator (RTDS) to verify its validity. To achieve this, a system level energy storage module (SESM) and a zonal level energy storage module (ZESM) are developed in RTDS to cooperate with PCONs to realize the control functionalities. In addition, a load shedding module which takes into account the reliability

  1. Impute DC link (IDCL) cell based power converters and control thereof

    DOEpatents

    Divan, Deepakraj M.; Prasai, Anish; Hernendez, Jorge; Moghe, Rohit; Iyer, Amrit; Kandula, Rajendra Prasad

    2016-04-26

    Power flow controllers based on Imputed DC Link (IDCL) cells are provided. The IDCL cell is a self-contained power electronic building block (PEBB). The IDCL cell may be stacked in series and parallel to achieve power flow control at higher voltage and current levels. Each IDCL cell may comprise a gate drive, a voltage sharing module, and a thermal management component in order to facilitate easy integration of the cell into a variety of applications. By providing direct AC conversion, the IDCL cell based AC/AC converters reduce device count, eliminate the use of electrolytic capacitors that have life and reliability issues, and improve system efficiency compared with similarly rated back-to-back inverter system.

  2. Enhancement of magnetic flux distribution in a DC superconducting electric motor

    NASA Astrophysics Data System (ADS)

    Hamid, N. A.; Ewe, L. S.; Chin, K. M.

    2013-06-01

    Most motor designs require an air gap between the rotor and stator to enable the armature to rotate freely. The interaction of magnetic flux from rotor and stator within the air gap will provide the thrust for rotational motion. Thus, the understanding of magnetic flux in the vicinity of the air gap is very important to mathematically calculate the magnetic flux generated in the area. In this work, a finite element analysis was employed to study the behavior of the magnetic flux in view of designing a synchronous DC superconducting electric motor. The analysis provides an ideal magnetic flux distribution within the components of the motor. From the flux plot analysis, it indicates that flux losses are mainly in the forms of leakage and fringe effect. The analysis also shows that the flux density is high at the area around the air gap and the rotor. The high flux density will provide a high force area that enables the rotor to rotate. In contrast, the other parts of the motor body do not show high flux density indicating low distribution of flux. Consequently, a bench top model of a DC superconducting motor was developed where by motor with a 2-pole type winding was chosen. Each field coil was designed with a racetrack-shaped double pancake wound using DI-BSCCO Bi-2223 superconducting tapes. The performance and energy efficiency of the superconducting motor was superior when compared to the conventional motor with similar capacity.

  3. Electric power distribution and load transfer system

    NASA Technical Reports Server (NTRS)

    Bradford, Michael P. (Inventor); Parkinson, Gerald W. (Inventor); Grant, Ross M. (Inventor)

    1989-01-01

    A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units.

  4. Electric power distribution and load transfer system

    NASA Technical Reports Server (NTRS)

    Bradford, Michael P. (Inventor); Parkinson, Gerald W. (Inventor); Grant, Ross M. (Inventor)

    1987-01-01

    A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units.

  5. Relative electron density distribution in a low nd helium dc discharge

    NASA Astrophysics Data System (ADS)

    Ganguly, Biswa N.; Scofield, James D.

    2016-09-01

    The axial and radial variations of the relative electron density distributions have been measured in an obstructed helium dc discharge by a laser collision induced fluorescence (LCIF) from 4 3D to 2 3P state at 447 nm. For this 1.75 Torr, 6.5 mm gap, 1.6 mA helium obstructed gas discharge, the on-axis LCIF intensity is mostly determined by the neutral atom collision. On the basis of this information, we have plotted the LCIF data to obtain a normalized electron density variation in the inter-electrode volume by plotting the ratio, I/-Io n -a x i s Io n -a x i s , where I is the radial variation of the LCIF intensity and Ion-axis is the on-axis LCIF intensity. The normalized LCIF data show an annular current density distribution in this obstructed discharge with the current peaking near the radial boundary of the electrodes.

  6. High frequency power distribution system

    NASA Technical Reports Server (NTRS)

    Patel, Mikund R.

    1986-01-01

    The objective of this project was to provide the technology of high frequency, high power transmission lines to the 100 kW power range at 20 kHz frequency. In addition to the necessary design studies, a 150 m long, 600 V, 60 A transmission line was built, tested and delivered for full vacuum tests. The configuration analysis on five alternative configurations resulted in the final selection of the three parallel Litz straps configuration, which gave a virtually concentric design in the electromagnetic sense. Low inductance, low EMI and flexibility in handling are the key features of this configuration. The final design was made after a parametric study to minimize the losses, weight and inductance. The construction of the cable was completed with no major difficulties. The R,L,C parameters measured on the cable agreed well with the calculated values. The corona tests on insulation samples showed a safety factor of 3.

  7. Evolution of an electron energy distribution function in a weak dc magnetic field in solenoidal inductive plasma

    SciTech Connect

    Lee, Min-Hyong; Choi, Seong Wook

    2008-12-01

    We investigated the evolution of the electron energy distribution function (EEDF) in a solenoidal inductively coupled plasma surrounded by an axial dc magnetic field. The increase in the dc magnetic field caused the EEDF to evolve from a bi-Maxwellian to a Maxwellian distribution. At the discharge center, the number of low energy electrons was significantly reduced while the high energy electron population showed little change when a weak dc magnetic field was present. However, at the discharge radial boundary, the high energy electron population decreased significantly with the magnetic field while the change in low energy population was not prominent compared to the discharge boundary. These changes in EEDFs at the boundary and center of the discharge are due to the radial confinement and the restriction of radial transport of electrons by dc magnetic field.

  8. Limitations of the Conventional Phase Advance Method for Constant Power Operation of the Brushless DC Motor

    SciTech Connect

    Lawler, J.S.

    2001-10-29

    The brushless dc motor (BDCM) has high-power density and efficiency relative to other motor types. These properties make the BDCM well suited for applications in electric vehicles provided a method can be developed for driving the motor over the 4 to 6:1 constant power speed range (CPSR) required by such applications. The present state of the art for constant power operation of the BDCM is conventional phase advance (CPA) [1]. In this paper, we identify key limitations of CPA. It is shown that the CPA has effective control over the developed power but that the current magnitude is relatively insensitive to power output and is inversely proportional to motor inductance. If the motor inductance is low, then the rms current at rated power and high speed may be several times larger than the current rating. The inductance required to maintain rms current within rating is derived analytically and is found to be large relative to that of BDCM designs using high-strength rare earth magnets. Th us, the CPA requires a BDCM with a large equivalent inductance.

  9. Solar photovoltaic charging of high voltage nickel metal hydride batteries using DC power conversion

    NASA Astrophysics Data System (ADS)

    Kelly, Nelson A.; Gibson, Thomas L.

    There are an increasing number of vehicle choices available that utilize batteries and electric motors to reduce tailpipe emissions and increase fuel economy. The eventual production of electricity and hydrogen in a renewable fashion, such as using solar energy, can achieve the long-term vision of having no tailpipe environmental impact, as well as eliminating the dependence of the transportation sector on dwindling supplies of petroleum for its energy. In this report we will demonstrate the solar-powered charging of the high-voltage nickel-metal hydride (NiMH) battery used in the GM 2-mode hybrid system. In previous studies we have used low-voltage solar modules to produce hydrogen via the electrolysis of water and to directly charge lithium-ion battery modules. Our strategy in the present work was to boost low-voltage PV voltage to over 300 V using DC-DC converters in order to charge the high-voltage NiMH battery, and to regulate the battery charging using software to program the electronic control unit supplied with the battery pack. A protocol for high-voltage battery charging was developed, and the solar to battery charging efficiency was measured under a variety of conditions. We believe this is the first time such high-voltage batteries have been charged using solar energy in order to prove the concept of efficient, solar-powered charging for battery-electric vehicles.

  10. Milliwatt dc/dc Inverter

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  11. Dynamic modeling of brushless dc motor-power conditioner unit for electromechanical actuator application

    NASA Technical Reports Server (NTRS)

    Demerdash, N. A.; Nehl, T. W.

    1979-01-01

    A comprehensive digital model for the analysis of the dynamic-instantaneous performance of a power conditioner fed samarium-cobalt permanent magnet brushless DC motor is presented. The particular power conditioner-machine system at hand, for which this model was developed, is a component of an actual prototype electromechanical actuator built for NASA-JSC as a possible alternative to hydraulic actuators as part of feasibility studies for the shuttle orbiter applications. Excellent correlation between digital simulated and experimentally obtained performance data was achieved for this specific prototype. This is reported on in this paper. Details of one component of the model, its applications and the corresponding results are given in this paper.

  12. Computer Power: Part 1: Distribution of Power (and Communications).

    ERIC Educational Resources Information Center

    Price, Bennett J.

    1988-01-01

    Discussion of the distribution of power to personal computers and computer terminals addresses options such as extension cords, perimeter raceways, and interior raceways. Sidebars explain: (1) the National Electrical Code; (2) volts, amps, and watts; (3) transformers, circuit breakers, and circuits; and (4) power vs. data wiring. (MES)

  13. Expert System Detects Power-Distribution Faults

    NASA Technical Reports Server (NTRS)

    Walters, Jerry L.; Quinn, Todd M.

    1994-01-01

    Autonomous Power Expert (APEX) computer program is prototype expert-system program detecting faults in electrical-power-distribution system. Assists human operators in diagnosing faults and deciding what adjustments or repairs needed for immediate recovery from faults or for maintenance to correct initially nonthreatening conditions that could develop into faults. Written in Lisp.

  14. High voltage systems (tube-type microwave)/low voltage system (solid-state microwave) power distribution

    NASA Technical Reports Server (NTRS)

    Nussberger, A. A.; Woodcock, G. R.

    1980-01-01

    SPS satellite power distribution systems are described. The reference Satellite Power System (SPS) concept utilizes high-voltage klystrons to convert the onboard satellite power from dc to RF for transmission to the ground receiving station. The solar array generates this required high voltage and the power is delivered to the klystrons through a power distribution subsystem. An array switching of solar cell submodules is used to maintain bus voltage regulation. Individual klystron dc voltage conversion is performed by centralized converters. The on-board data processing system performs the necessary switching of submodules to maintain voltage regulation. Electrical power output from the solar panels is fed via switch gears into feeder buses and then into main distribution buses to the antenna. Power also is distributed to batteries so that critical functions can be provided through solar eclipses.

  15. Earth to space dc to dc power transmission system utilizing a microwave beam as source of energy for electric propelled interorbital vehicles

    NASA Technical Reports Server (NTRS)

    Brown, W. C.

    1985-01-01

    The paper contributes to the credibility of an electric propelled interorbital transportation system by introducing a new low-mass source of continuous dc power for electric propulsion and illustrating how the source can be economically tied to an electric utility on earth by an electronically steered microwave beam. The new thin-film rectenna, which functions as the receiving end of an earth-to-space microwave power transmission system is described. It is easily fabricated, is over 80 percent efficient, has a specific mass of no more than 2 kilograms per kilowatt of continuous dc power output, and is well adapted for deployment in space. The paper then describes a complete system consisting of the interorbital vehicle and the microwave power transmission system that supplies it with power. A design scenario is used to obtain performance data from the system in terms of vehicle transfer times, payload fractions, and costs. Electric energy costs are found to be less than $1000 per kilogram of payload delivered to geosynchronous orbit from low-earth orbit.

  16. Space Solar Power Management and Distribution (PMAD)

    NASA Technical Reports Server (NTRS)

    Lynch, Thomas H.

    2000-01-01

    This paper presents, in viewgraph form, SSP PMAD (Space Solar Power Management and Distribution). The topics include: 1) Architecture; 2) Backside Thermal View; 3) Solar Array Interface; 4) Transformer design and risks; 5) Twelve phase rectifier; 6) Antenna (80V) Converters; 7) Distribution Cables; 8) Weight Analysis; and 9) PMAD Summary.

  17. Analysis of Distribution of Nonmetallic Inclusions in Aluminum DC-Cast Billets and Slabs

    NASA Astrophysics Data System (ADS)

    Jaradeh, Majed M.; Carlberg, Torbjorn

    2012-02-01

    Inclusion distribution was studied in commercial aluminum DC-cast billets and slabs using a newly developed deep-etching method. Analyses revealed a nonuniform distribution of nonmetallic inclusions across billet diameters and lengths, and also across slab thicknesses and widths. In as-cast billets, more inclusions were found at the beginning and end of the billet length; more were present near the cross-section center than near the surface. In slabs, inclusions were located mostly within 13 mm of the surface and in a band between the centerline and the surface. Few inclusions were found 60 to 100 mm from the slab surface or at the centerline. In addition, comparing slab quality after casting using three types of ceramic foam filters (CFFs; i.e., 30 ppi, 50 ppi, and 50 ppi + HF) revealed significant differences in inclusion size, number, and distribution. Casting slabs using a finer pore-size filter (50 ppi) reduced the number of non-metallic inclusions greatly. The inclusion distribution patterns observed in the solidified slabs are discussed in terms of melt flow during casting.

  18. Description of real-time Ada software implementation of a power system monitor for the Space Station Freedom PMAD DC testbed

    NASA Technical Reports Server (NTRS)

    Ludwig, Kimberly; Mackin, Michael; Wright, Theodore

    1991-01-01

    The authors describe the Ada language software developed to perform the electrical power system monitoring functions for the NASA Lewis Research Center's Power Management and Distribution (PMAD) DC testbed. The results of the effort to implement this monitor are presented. The PMAD DC testbed is a reduced-scale prototype of the electric power system to be used in Space Station Freedom. The power is controlled by smart switches known as power control components (or switchgear). The power control components are currently coordinated by five Compaq 386/20e computers connected through an 802.4 local area network. The power system monitor algorithm comprises several functions, including periodic data acquisition, data smoothing, system performance analysis, and status reporting. Data are collected from the switchgear sensors every 100 ms, then passed through a 2-Hz digital filter. System performance analysis includes power interruption and overcurrent detection. The system monitor required a hardware timer interrupt to activate the data acquisition function. The execution time of the code was optimized by using an assembly language routine. The routine allows direct vectoring of the processor to Ada language procedures that perform periodic control activities.

  19. Cathode power distribution system and method of using the same for power distribution

    DOEpatents

    Williamson, Mark A; Wiedmeyer, Stanley G; Koehl, Eugene R; Bailey, James L; Willit, James L; Barnes, Laurel A; Blaskovitz, Robert J

    2014-11-11

    Embodiments include a cathode power distribution system and/or method of using the same for power distribution. The cathode power distribution system includes a plurality of cathode assemblies. Each cathode assembly of the plurality of cathode assemblies includes a plurality of cathode rods. The system also includes a plurality of bus bars configured to distribute current to each of the plurality of cathode assemblies. The plurality of bus bars include a first bus bar configured to distribute the current to first ends of the plurality of cathode assemblies and a second bus bar configured to distribute the current to second ends of the plurality of cathode assemblies.

  20. High voltage-high power components for large space power distribution systems

    NASA Technical Reports Server (NTRS)

    Renz, D. D.

    1984-01-01

    Space power components including a family of bipolar power switching transistors, fast switching power diodes, heat pipe cooled high frequency transformers and inductors, high frequency conduction cooled transformers, high power-high frequency capacitors, remote power controllers and rotary power transfer devices were developed. Many of these components such as the power switching transistors, power diodes and the high frequency capacitor are commercially available. All the other components were developed to the prototype level. The dc/dc series resonant converters were built to the 25 kW level.

  1. Electrochemical treatment of tannery effluent using a battery integrated DC-DC converter and solar PV power supply--an approach towards environment and energy management.

    PubMed

    Iyappan, K; Basha, C Ahmed; Saravanathamizhan, R; Vedaraman, N; Tahiyah Nou Shene, C A; Begum, S Nathira

    2014-01-01

    Electrochemical oxidation of tannery effluent was carried out in batch, batch recirculation and continuous reactor configurations under different conditions using a battery-integrated DC-DC converter and solar PV power supply. The effect of current density, electrolysis time and fluid flow rate on chemical oxygen demand (COD) removal and energy consumption has been evaluated. The results of batch reactor show that a COD reduction of 80.85% to 96.67% could be obtained. The results showed that after 7 h of operation at a current density of 2.5 A dm(-2) and flow rate of 100 L h(-1) in batch recirculation reactor, the removal of COD is 82.14% and the specific energy consumption was found to be 5.871 kWh (kg COD)(-1) for tannery effluent. In addition, the performance of single pass flow reactors (single and multiple reactors) system of various configurations are analyzed.

  2. Lowest of AC-DC power output for electrostrictive polymers energy harvesting systems

    NASA Astrophysics Data System (ADS)

    Meddad, Mounir; Eddiai, Adil; Hajjaji, Abdelowahed; Guyomar, Daniel; Belkhiat, Saad; Boughaleb, Yahia; Chérif, Aida

    2013-11-01

    Advances in technology led to the development of electronic circuits and sensors with extremely low electricity consumption. At the same time, structural health monitoring, technology and intelligent integrated systems created a need for wireless sensors in hard to reach places in aerospace vehicles and large civil engineering structures. Powering sensors with energy harvesters eliminates the need to replace batteries on a regular basis. Scientists have been forced to search for new power source that are able to harvested energy from their surrounding environment (sunlight, temperature gradients etc.). Electrostrictive polymer belonging to the family of electro-active polymers, offer unique properties for the electromechanical transducer technology has been of particular interest over the last few years in order to replace conventional techniques such as those based on piezoelectric or electromagnetic, these materials are highly attractive for their low-density, with large strain capability that can be as high as two orders of magnitude greater than the striction-limited, rigid and fragile electroactive ceramics. Electrostrictive polymers sensors respond to vibration with an ac output signal, one of the most important objectives of the electronic interface is to realize the required AC-DC conversion. The goal of this paper is to design an active, high efficiency power doubler converter for electrostrictive polymers exclusively uses a fraction of the harvested energy to supply its active devices. The simulation results show that it is possible to obtain a maximum efficiency of the AC-DC converter equal to 80%. Premiliminary experimental measurements were performed and the results obtained are in good agreement with simulations.

  3. Waveform magnetic field survey in Russian DC and Swiss AC powered trains: a basis for biologically relevant exposure assessment.

    PubMed

    Ptitsyna, N G; Kopytenko, Y A; Villoresi, G; Pfluger, D H; Ismaguilov, V; Iucci, N; Kopytenko, E A; Zaitzev, D B; Voronov, P M; Tyasto, M I

    2003-12-01

    Recent epidemiological studies suggest a link between transport magnetic fields (MF) and certain adverse health effects. We performed measurements in workplaces of engineers on Russian DC and Swiss AC powered (16.67 Hz) electric trains using a computer based waveform capture system with a 200 Hz sampling rate. MF in DC and AC trains show complex combinations of static and varying components. The most probable levels of quasistatic MF (0.001-0.03 Hz) were in the range 40 microT. Maximum levels of 120 microT were found in DC powered locomotives. These levels are much higher than the geomagnetic field at the site of measurements. MF encountered both in DC and AC powered rail systems showed irregular temporal variability in frequency composition and amplitude characteristics across the whole frequency range studied (0-50 Hz); however, more than 90% of the magnetic field power was concentrated in frequencies DC powered trains amplitudes of field variations sharply decrease from static to approximately 3-4 Hz fields; for higher frequencies a tendency of slow decrease is observed up to 50 Hz. For frequencies higher than 1 Hz average amplitudes of magnetic field variations are less than 1 microT; maximum levels reach tens of microtesla. At frequencies lower than 15 Hz, the average magnetic field generated by Swiss AC powered locomotives was approximately 10 times greater than fields observed in Russian DC powered trains.

  4. [Spatial distribution of electrons with high energy in atmospheric pressure glow discharge excited by DC voltage].

    PubMed

    Liu, Zhi-qiang; Jia, Peng-ying; Liu, Tie

    2013-09-01

    Atmospheric pressure glow discharge excited by a DC voltage was realized in a 6 mm air gap by using a needle-water electrode discharge device. The atompheric pressure glow discharge has characteristic regions such as a cathode fall, a negative glow, a Faraday dark space, a positive column and an anode glow. The discharge is a normal glow through analyzing its voltage-current curve. The emission intensity of 337.1 nm spectral line from the second positive system of N2 was investigated because it can indicate the electron density with high energy. Results show that the maxima of high energy electrons appears in the vicinity of the needle tip, and it almost remains constant at other locations. The density of high energy electrons decreases with increasing the voltage. Similarly, it decreases with increasing the value of the ballast resistor. Oxygen atom is important for the sterilization and disinfection. The distribution of oxygen atom was also investigated by optical emission spectroscopy. It was found that the oxygen distribution is similar with the distribution of high energy electrons. These results are important for the application of atmospheric pressure glow discharge in environmental protection and biological treatment. PMID:24369623

  5. Comparative Study of Cu Films Prepared by DC, High-Power Pulsed and Burst Magnetron Sputtering

    NASA Astrophysics Data System (ADS)

    Solovyev, A. A.; Oskirko, V. O.; Semenov, V. A.; Oskomov, K. V.; Rabotkin, S. V.

    2016-08-01

    A comparative study of deposition rate, adhesion, structural and electrical properties of nanocrystalline copper thin films deposited using direct current magnetron sputtering (DCMS) and different regimes of high power pulsed magnetron sputtering is presented. High-power impulse magnetron sputtering (HIPIMS) and burst regime (pulse packages) of magnetron sputtering are investigated. The ion and atomic flows toward the growing film during magnetron sputtering of a Cu target are determined. X-ray diffraction, scanning electron microscopy and atomic force microscopy were used to observe the structural characterization of the films. The resistivity of the films was measured using four-point probe technique. In all sputtering regimes, Cu films have mixture crystalline orientations of [111], [200], [311] and [220] in the direction of the film growth. As peak power density in studied deposition regimes was different in order of magnitude (from 15 W/cm2 in DC regime to 3700 W/cm2 in HIPIMS), film properties were also greatly different. DCMS Cu films exhibit a porous columnar grain structure. In contrast, HIPIMS Cu films have a slightly columnar and denser composition. Cu films deposited using burst regimes at peak power density of 415 W cm-2 and ion-to-atom ratio of about 5 have the densest composition and smallest electrical resistance.

  6. Grid-connected distributed solar power systems

    NASA Astrophysics Data System (ADS)

    Moyle, R.; Chernoff, H.; Schweizer, T.

    This paper discusses some important, though often ignored, technical and economic issues of distributed solar power systems: protection of the utility system and nonsolar customers requires suitable interfaced equipment. Purchase criteria must mirror reality; most analyses use life-cycle costing with low discount rates - most buyers use short payback periods. Distributing, installing, and marketing small, distributed solar systems is more costly than most analyses estimate. Results show that certain local conditions and uncommon purchase considerations can combine to make small, distributed solar power attractive, but lower interconnect costs (per kW), lower marketing and product distribution costs, and more favorable purchase criteria make large, centralized solar energy more attractive. Specifically, the value of dispersed solar systems to investors and utilities can be higher than $2000/kw. However, typical residential owners place a value of well under $1000 on the installed system.

  7. Vibration Monitoring of Power Distribution Poles

    SciTech Connect

    Clark Scott; Gail Heath; John Svoboda

    2006-04-01

    Some of the most visible and least monitored elements of our national security infrastructure are the poles and towers used for the distribution of our nation’s electrical power. Issues surrounding these elements within the United States include safety such as unauthorized climbing and access, vandalism such as nut/bolt removal or destructive small arms fire, and major vandalism such as the downing of power poles and towers by the cutting of the poles with a chainsaw or torches. The Idaho National Laboratory (INL) has an ongoing research program working to develop inexpensive and sensitive sensor platforms for the monitoring and characterization of damage to the power distribution infrastructure. This presentation covers the results from the instrumentation of a variety of power poles and wires with geophone assemblies and the recording of vibration data when power poles were subjected to a variety of stimuli. Initial results indicate that, for the majority of attacks against power poles, the resulting signal can be seen not only on the targeted pole but on sensors several poles away in the distribution network and a distributed sensor system can be used to monitor remote and critical structures.

  8. Correlated product distributions from ketene dissociation measured by dc sliced ion imaging.

    PubMed

    Komissarov, Anatoly V; Minitti, Michael P; Suits, Arthur G; Hall, Gregory E

    2006-01-01

    Speed distributions of spectroscopically selected CO photoproducts of 308 nm ketene photodissociation have been measured by dc sliced ion imaging. Structured speed distributions are observed that match the clumps and gaps in the singlet CH2 rotational density of states. The effects of finite time gates in sliced ion imaging are important for the accurate treatment of quasicontinuous velocity distributions extending into the thickly sliced and fully projected regime, and an inversion algorithm has been implemented for the special case of isotropic fragmentation. With accurate velocity calibration and careful treatment of the velocity resolution, the new method allows us to characterize the coincident rotational state distribution of CH2 states as a smoothly varying deviation from an unbiased phase space theory (PST) limit, similar to a linear-surprisal analysis. High-energy rotational states of CH2 are underrepresented compared to PST in coincidence with all detected CO rotational states. There is no evidence for suppression of the fastest channels, as had been reported in two previous studies of this system by other techniques. The relative contributions of ground and first vibrationally excited singlet CH2 states in coincidence with selected rotational states of CO (upsilon=0) are well resolved and in remarkably good agreement with PST, despite large deviations from the PST rotational distributions in the CH2 fragments. At 308 nm, the singlet CH2 (upsilon2=0) and (upsilon2=1) channels are 2350 and 1000 cm(-1) above their respective thresholds. The observed vibrational branching is consistent with saturation at increasing energies of the energy-dependent suppression of rates with respect to the PST limit, attributed to a tightening variational transition state.

  9. An experimental study of energy loss mechanisms and efficiency consideration in the low power dc arcjet

    NASA Technical Reports Server (NTRS)

    Curran, F. M.

    1985-01-01

    The potential utility of the low power dc arcjet in auxiliary propulsion was investigated. It was indicated that improvements in the areas of stability, energy efficiency, reliability, and electrode erosion are necessary to obtain a useful device. A water-cooled arcjet simulator was tested to investigate both the energy loss mechanisms at the electrodes and the stability of different conventional arcjet configurations in the presence of a vortex flow field. It is shown that in certain configurations only 25 to 30% of the input energy is lost to the electrodes. It is also shown that vortex stabilization is not difficult to obtain in many cases at the flow rates used and that a careful starting procedure is effective in minimizing electrode damage.

  10. An experimental study of energy loss mechanisms and efficiency considerations in the low power dc arcjet

    NASA Technical Reports Server (NTRS)

    Curran, F. M.

    1985-01-01

    The potential utility of the low power dc arcjet in auxiliary propulsion was investigated. It was indicated that improvements in the areas of stability, energy efficiency, reliability, and electrode erosion are necessary to obtain a useful device. A water-cooled arcjet simulator was tested to investigate both the energy loss mechanisms at the electrodes and the stability of different conventional arcjet configurations in the presence of a vortex flow field. It is shown that in certain configurations only 25 to 30 percent of the input energy is lost to the electrodes. It is also shown that vortex stabilization is not difficult to obtain in many cases at the flow rates used and that a careful starting procedure is effective in minimizing electrode damage.

  11. Voltage source ac-to-dc converters for high-power transmitters

    NASA Technical Reports Server (NTRS)

    Cormier, R.

    1990-01-01

    This work was done to optimize the design of the components used for the beam power supply, which is a component of the transmitters in the Deep Space Network (DSN). The major findings are: (1) the difference in regulation between a six-pulse and a twelve-pulse converter is at most 7 percent worse for the twelve-pulse converter; (2) the commutation overlap angle of a current source converter equals that of a voltage source converter with continuous line currents; (3) the sources of uncharacteristic harmonics are identified with SPICE simulation; (4) the use of an imperfect phase-shifting transformer for the twelve-pulse converter generates a harmonic at six times the line frequency; and (5) the assumptions usually made in analyzing converters can be relaxed with SPICE simulation. The results demonstrate the suitability of using SPICE simulation to obtain detailed performance predictions of ac-to-dc converters.

  12. Fault-tolerant power distribution system

    NASA Technical Reports Server (NTRS)

    Volp, Jeffrey A. (Inventor)

    1987-01-01

    A fault-tolerant power distribution system which includes a plurality of power sources and a plurality of nodes responsive thereto for supplying power to one or more loads associated with each node. Each node includes a plurality of switching circuits, each of which preferably uses a power field effect transistor which provides a diode operation when power is first applied to the nodes and which thereafter provides bi-directional current flow through the switching circuit in a manner such that a low voltage drop is produced in each direction. Each switching circuit includes circuitry for disabling the power field effect transistor when the current in the switching circuit exceeds a preselected value.

  13. Raman Channel Temperature Measurement of SiC MESFET as a Function of Ambient Temperature and DC Power

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Eldridge, Jeffrey J.; Krainsky, Isay L.

    2009-01-01

    Raman spectroscopy is used to measure the junction temperature of a Cree SiC MESFET as a function of the ambient temperature and DC power. The carrier temperature, which is approximately equal to the ambient temperature, is varied from 25 C to 450 C, and the transistor is biased with VDS=10V and IDS of 50 mA and 100 mA. It is shown that the junction temperature is approximately 52 and 100 C higher than the ambient temperature for the DC power of 500 and 1000 mW, respectively.

  14. The dc-to-dc converters employing staggered-phase power switches with two-loop control

    NASA Technical Reports Server (NTRS)

    Wester, G. W. (Inventor)

    1976-01-01

    A switched inductor voltage is coupled to a sense winding in each phase, and all sense windings are connected in series to one of two feedback loops to provide a signal that indicates when one of the power switches is on as the principal determinant of switching instants. A sequencer is triggered each time a pulse generator is triggered to turn on a different power switch in sequence at each switching instant.

  15. Local digital control of power electronic converters in a dc microgrid based on a-priori derivation of switching surfaces

    NASA Astrophysics Data System (ADS)

    Banerjee, Bibaswan

    In power electronic basedmicrogrids, the computational requirements needed to implement an optimized online control strategy can be prohibitive. The work presented in this dissertation proposes a generalized method of derivation of geometric manifolds in a dc microgrid that is based on the a-priori computation of the optimal reactions and trajectories for classes of events in a dc microgrid. The proposed states are the stored energies in all the energy storage elements of the dc microgrid and power flowing into them. It is anticipated that calculating a large enough set of dissimilar transient scenarios will also span many scenarios not specifically used to develop the surface. These geometric manifolds will then be used as reference surfaces in any type of controller, such as a sliding mode hysteretic controller. The presence of switched power converters in microgrids involve different control actions for different system events. The control of the switch states of the converters is essential for steady state and transient operations. A digital memory look-up based controller that uses a hysteretic sliding mode control strategy is an effective technique to generate the proper switch states for the converters. An example dcmicrogrid with three dc-dc boost converters and resistive loads is considered for this work. The geometric manifolds are successfully generated for transient events, such as step changes in the loads and the sources. The surfaces corresponding to a specific case of step change in the loads are then used as reference surfaces in an EEPROM for experimentally validating the control strategy. The required switch states corresponding to this specific transient scenario are programmed in the EEPROM as a memory table. This controls the switching of the dc-dc boost converters and drives the system states to the reference manifold. In this work, it is shown that this strategy effectively controls the system for a transient condition such as step changes

  16. Galileo spacecraft power management and distribution system

    NASA Technical Reports Server (NTRS)

    Detwiler, R. C.; Smith, R. L.

    1990-01-01

    The Galileo PMAD (power management and distribution system) is described, and the design drivers that established the final as-built hardware are discussed. The spacecraft is powered by two general-purpose heat-source-radioisotope thermoelectric generators. Power bus regulation is provided by a shunt regulator. Galileo PMAD distributes a 570-W beginning of mission (BOM) power source to a user complement of some 137 load elements. Extensive use of pyrotechnics requires two pyro switching subassemblies. They initiate 148 squibs which operate the 47 pyro devices on the spacecraft. Detection and correction of faults in the Galileo PMAD is an autonomous feature dictated by requirements for long life and reliability in the absence of ground-based support. Volatile computer memories in the spacecraft command and data system and attitude control system require a continuous source of backup power during all anticipated power bus fault scenarios. Power for the Jupiter Probe is conditioned, isolated, and controlled by a Probe interface subassembly. Flight performance of the spacecraft and the PMAD has been successful to date, with no major anomalies.

  17. Test Results of Selected Commercial DC/DC Converters under Cryogenic Temperatures - A Digest

    NASA Technical Reports Server (NTRS)

    Patterson, Richard; Hammoud, Ahmad

    2010-01-01

    DC/DC converters are widely used in space power systems in the areas of power management and distribution, signal conditioning, and motor control. Design of DC/DC converters to survive cryogenic temperatures will improve the power system performance, simplify design, and reduce development and launch costs. In this work, the performance of nine COTS modular, low-tomedium power DC/DC converters was investigated under cryogenic temperatures. The converters were evaluated in terms of their output regulation, efficiency, and input and output currents. At a given temperature, these properties were obtained at various input voltages and at different load levels. A summary on the performance of the tested converters was given. More comprehensive testing and in-depth analysis of performance under long-term exposure to extreme temperatures are deemed necessary to establish the suitability of these and other devices for use in the harsh environment of space exploration missions.

  18. DC Studies of Coaxial Vacuum Gap Breakdown for Pulsed Power Liners

    NASA Astrophysics Data System (ADS)

    Meisenhelder, C. M.; Bott-Suzuki, S. C.; Haas, D. M.

    2013-10-01

    Previously, pulsed power loads for inertial fusion have been envisioned as cylindrical wire arrays, which could easily be constrained to be in contact with both electrodes for a good electrical connection. Recently, solid liners have become the load of choice for Magnetized Liner Inertial Fusion (MagLIF) experiments which are currently being conducted on the Z-Machine at Sandia National Laboratory. These liners cannot easily be constrained as previous wire loads were, particularly for a repetitive system. The result is a vacuum gap between the driver electrodes and load, which may have unknown effects on the stability and development of the plasma system. DC voltages up to 30 kV will be applied to coaxial electrodes in vacuum to simulate a variety of possible gap parameters for pulsed power liners. This work investigates the breakdown-timing, azimuthal symmetry and coupling of the driver energy to the load as a function of gap parameters to better understand the subsequent behavior of a liner load. Supported by the National Undergraduate Fellowship Program in Plasma Physics and Fusion Energy Sciences and under DE-NA0001836 and GA IR&D funding.

  19. 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)

  20. Kinetic-Energy Distributions of Positive and Negative Ions in DC Townsend Discharges of Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Rao, M. V. V. S.; van Brunt, R. J.; Olthoff, J. K.

    1997-10-01

    Ion kinetic-energy distributions (IEDs), mean energies, and relative abundances are measured for CO_2^+, CO^+, O_2^+, O^+, C^+, and O^- ions produced in dc Townsend discharges in pure carbon dioxide. The discharges are generated at electric field-to-gas density ratios (E/N) ranging from 3.5 x 10-18 Vm^2 to 20 x 10-18 Vm^2 (3.5 to 20 kTd). Ions sampled from the discharge through a small orifice in the center of the grounded electrode were energy and mass analyzed by an electrostatic energy analyzer attached to a quadrupole mass spectrometer.(M. V. V. S. Rao, R. J. Van Brunt, and J. K. Olthoff, Phys. Rev. E 54), 5641 (1996) In the present experiments, CO_2^+ was determined to be the dominant positive ion (greater than 85%) at all E/N. The IEDs of CO_2^+, O_2^+, and O^+ are Maxwellian at all E/N, with CO^+ exhibiting non-Maxwellian behavior above 10 kTd, and C^+ exhibiting non-Maxwellian behavior at all E/N. Negative ion fluxes were substantially lower than positive ion fluxes, with O^- being the only detectable negative ion. The IEDs for O^- are Maxwellian at 6 kTd and below. The fact that O^- is the only negative ion indicates that no asymmetric charge transfer exists for O^- in CO_2.

  1. The spatial distribution of negative oxygen ion densities in a dc reactive magnetron discharge

    NASA Astrophysics Data System (ADS)

    Scribbins, Steven; Bowes, Michael; Bradley, James W.

    2013-01-01

    Using Langmuir probe-assisted eclipse laser photodetachment, the spatial distribution of O- densities in the bulk plasma of magnetron sputter tool has been determined for a range of pressures, 0.79 to 2.40 Pa. The discharge was operated in dc (200 W) with a Ti target and a fixed oxygen-argon pressure ratio of 0.2, in poisoned mode. Measurements show significant O- densities occupying an annulus downstream from the magnetic trap in regions of most positive plasma potential. With increasing pressure the region of high O- density expands and the peak densities increase reaching ˜1.5 × 1016 m-3 at 2.40 Pa, corresponding to an O- to electron density ratio (electronegativity α) of ˜2. Outside the area of dense negative ions, and in regions of the magnetic trap accessible to our probe we measure α < 0.2. The results show that these reactive magnetron plasmas, utilized for oxide film production, to be highly electronegative in regions close to the substrate.

  2. The importance of population susceptibility for air pollution risk assessment: a case study of power plants near Washington, DC.

    PubMed

    Levy, Jonathan I; Greco, Susan L; Spengler, John D

    2002-12-01

    In evaluating risks from air pollution, health impact assessments often focus on the magnitude of the impacts without explicitly considering the distribution of impacts across subpopulations. In this study, we constructed a model to estimate the magnitude and distribution of health benefits associated with emission controls at five older power plants in the Washington, DC, area. We used the CALPUFF atmospheric dispersion model to determine the primary and secondary fine-particulate-matter (< 2.5 micro m in aerodynamic diameter) concentration reductions associated with the hypothetical application of "Best Available Control Technology" to the selected power plants. We combined these concentration reductions with concentration-response functions for mortality and selected morbidity outcomes, using a conventional approach as well as considering susceptible subpopulations. Incorporating susceptibility had a minimal effect on total benefits, with central estimates of approximately 240 fewer premature deaths, 60 fewer cardiovascular hospital admissions (CHA), and 160 fewer pediatric asthma emergency room visits (ERV) per year. However, because individuals with lower education appear to have both higher background mortality rates and higher relative risks for air-pollution-related mortality, stratifying by educational attainment implies that 51% of the mortality benefits accrue among the 25% of the population with less than high school education. Similarly, diabetics and African Americans bear disproportionate shares of the CHA and ERV benefits, respectively. Although our ability to characterize subpopulations is constrained by the available information, our analysis demonstrates that incorporation of susceptibility information significantly affects demographic and geographic patterns of health benefits and enhances our understanding of individuals likely to benefit from emission controls.

  3. The importance of population susceptibility for air pollution risk assessment: a case study of power plants near Washington, DC.

    PubMed Central

    Levy, Jonathan I; Greco, Susan L; Spengler, John D

    2002-01-01

    In evaluating risks from air pollution, health impact assessments often focus on the magnitude of the impacts without explicitly considering the distribution of impacts across subpopulations. In this study, we constructed a model to estimate the magnitude and distribution of health benefits associated with emission controls at five older power plants in the Washington, DC, area. We used the CALPUFF atmospheric dispersion model to determine the primary and secondary fine-particulate-matter (< 2.5 micro m in aerodynamic diameter) concentration reductions associated with the hypothetical application of "Best Available Control Technology" to the selected power plants. We combined these concentration reductions with concentration-response functions for mortality and selected morbidity outcomes, using a conventional approach as well as considering susceptible subpopulations. Incorporating susceptibility had a minimal effect on total benefits, with central estimates of approximately 240 fewer premature deaths, 60 fewer cardiovascular hospital admissions (CHA), and 160 fewer pediatric asthma emergency room visits (ERV) per year. However, because individuals with lower education appear to have both higher background mortality rates and higher relative risks for air-pollution-related mortality, stratifying by educational attainment implies that 51% of the mortality benefits accrue among the 25% of the population with less than high school education. Similarly, diabetics and African Americans bear disproportionate shares of the CHA and ERV benefits, respectively. Although our ability to characterize subpopulations is constrained by the available information, our analysis demonstrates that incorporation of susceptibility information significantly affects demographic and geographic patterns of health benefits and enhances our understanding of individuals likely to benefit from emission controls. PMID:12460806

  4. Power Management and Distribution System Developed for Thermionic Power Converters

    NASA Technical Reports Server (NTRS)

    Baez, Anastacio N.

    1998-01-01

    A spacecraft solar, bimodal system combines propulsion and power generation into a single integrated system. An Integrated Solar Upper Stage (ISUS) provides orbital transfer capabilities, power generation for payloads, and onboard propulsion to the spacecraft. A key benefit of a bimodal system is a greater payload-to-spacecraft mass ratio resulting in lower launch vehicle requirements. Scaling down to smaller launch vehicles increases space access by reducing overall mission cost. NASA has joined efforts with the Air Force Phillips Laboratory to develop enabling technologies for such a system. The NASA/Air Force bimodal concept uses solar concentrators to focus energy into an integrated power plant. This power plant consists of a graphite core that stores thermal energy within a cavity. An array of thermionic converters encircles the graphite cavity and provides electrical energy conversion functions. During the power generation phase of the bimodal system, the thermionic converters are exposed to the heated cavity and convert the thermal energy to electricity. Near-term efforts of the ISUS bimodal program are focused on a ground demonstration of key technologies in order to proceed to a full space flight test. Thermionic power generation is one key technology of the bimodal concept. Thermionic power converters impose unique operating requirements upon a power management and distribution (PMAD) system design. Single thermionic converters supply large currents at very low voltages. Operating voltages can vary over a range of up to 3 to 1 as a function of operating temperature. Most spacecraft loads require regulated 28-volts direct-current (Vdc) power. A combination of series-connected converters and powerprocessing boosters is required to deliver power to the spacecraft's payloads at this level.

  5. A Kalman filtering based control scheme for the improvement of dynamic performance of an AC/DC power system

    NASA Astrophysics Data System (ADS)

    Pecen, Recayi

    In this dissertation, two major accomplishments are achieved. First, the feasibility of a proposed Wyoming to California HVDC system having the ratings of 1000 MW, ±500 kV, 2 kA, 860 miles and 12-pulse bipolar lines is shown for exporting Wyoming's electrical power resources to the heavy loaded western states. The second and the main objective of this dissertation is the development of a Kalman filtering (KF) based control scheme applied to an ac/dc power system. It is shown that the use KF algorithm to estimate some of the system states and utilizing them in a proportional Integral (PI) controller which has a better performance for this specific control scheme have resulted in a better dynamic performance of the proposed system. A set of case studies has shown that the system dynamic performance is improved for most of the contingencies. Ac and dc noisy voltage and current measurements received from the simulated ac/dc power system are sent to the KF estimation algorithm. The noise-separated best estimates of measurable states are computed and sent to a PI controller-based current and firing angle control subsections in order to provide a set of optimum thyristor firing angles for both converter stations during and after contingencies until the normal operation is reached. To evaluate the dynamic performance of the system with the KF algorithm, the model is simulated by a well-known digital simulation package, Electromagnetic Transients DC Program (PSCAD/EMTDC) of Manitoba HVDC Research Center. To apply the KF algorithm, a general, linearized, state-space model of the proposed ac/dc system, appropriate for analyzing both the KF and the electromagnetics transients, is derived first. The derived model enables the representation of an ac power system with two ac sources and one HVDC line with a parallel ac line connecting the two systems. It is shown that system eigenvalues of the discretized system model for a normal operating point are inside the unit circle that

  6. Uncertainty evaluation in BEACON power distribution monitoring

    SciTech Connect

    Morita, T.; Goldstein, N.P. )

    1989-11-01

    BEACON is an advanced operational core support package that has a three-dimensional nodal code as its cornerstone. The three-dimensional calculation includes all necessary pressurized water reactor feedback effects. The generation of the measured power distribution from the core instrumentation is one of the primary functions of the core-monitoring software. The purpose of this paper is to discuss evaluation of the uncertainty in the measured assembly power from the BEACON system. The study covers not only the normal operating conditions, but off-normal situations to demonstrate BEACON's applicability for that condition.

  7. The Use of Software Agents for Autonomous Control of a DC Space Power System

    NASA Technical Reports Server (NTRS)

    May, Ryan D.; Loparo, Kenneth A.

    2014-01-01

    In order to enable manned deep-space missions, the spacecraft must be controlled autonomously using on-board algorithms. A control architecture is proposed to enable this autonomous operation for an spacecraft electric power system and then implemented using a highly distributed network of software agents. These agents collaborate and compete with each other in order to implement each of the control functions. A subset of this control architecture is tested against a steadystate power system simulation and found to be able to solve a constrained optimization problem with competing objectives using only local information.

  8. Simulation analysis of three-phase current type AC-to-DC converter with high power factor

    SciTech Connect

    Okui, Yoshiaki; Yamada, Hajime

    1997-03-01

    A new three-phase current type AC-to-DC converter has been developed by the authors. This paper describes the principle of the circuit operation and the circuit configuration of the AC-to-DC converter controlled by PWM. Simulation analysis of each waveform, such as AC and DC voltages and currents, are calculated by Euler`s method. The simulated values of the total power factor agreed with the measured values within the difference of 5.8% on the condition of full load, 10kW. When the AC side voltage is unbalanced, it is found by simulation that the total harmonic distortion controlled by both feedforward control and AC side current feedback control (proportion gain, k{sub 4} = 1) is restrained at only 38% compared with only feedforward control (k{sub 4} = 0).

  9. Relativity, nonextensivity, and extended power law distributions.

    PubMed

    Silva, R; Lima, J A S

    2005-11-01

    A proof of the relativistic theorem by including nonextensive effects is given. As it happens in the nonrelativistic limit, the molecular chaos hypothesis advanced by Boltzmann does not remain valid, and the second law of thermodynamics combined with a duality transformation implies that the parameter lies on the interval [0,2]. It is also proven that the collisional equilibrium states (null entropy source term) are described by the relativistic power law extension of the exponential Juttner distribution which reduces, in the nonrelativistic domain, to the Tsallis power law function. As a simple illustration of the basic approach, we derive the relativistic nonextensive equilibrium distribution for a dilute charged gas under the action of an electromagnetic field . Such results reduce to the standard ones in the extensive limit, thereby showing that the nonextensive entropic framework can be harmonized with the space-time ideas contained in the special relativity theory. PMID:16383791

  10. Relativity, nonextensivity, and extended power law distributions.

    PubMed

    Silva, R; Lima, J A S

    2005-11-01

    A proof of the relativistic theorem by including nonextensive effects is given. As it happens in the nonrelativistic limit, the molecular chaos hypothesis advanced by Boltzmann does not remain valid, and the second law of thermodynamics combined with a duality transformation implies that the parameter lies on the interval [0,2]. It is also proven that the collisional equilibrium states (null entropy source term) are described by the relativistic power law extension of the exponential Juttner distribution which reduces, in the nonrelativistic domain, to the Tsallis power law function. As a simple illustration of the basic approach, we derive the relativistic nonextensive equilibrium distribution for a dilute charged gas under the action of an electromagnetic field . Such results reduce to the standard ones in the extensive limit, thereby showing that the nonextensive entropic framework can be harmonized with the space-time ideas contained in the special relativity theory.

  11. High-Efficiency dc/dc Converter

    NASA Technical Reports Server (NTRS)

    Sturman, J.

    1982-01-01

    High-efficiency dc/dc converter has been developed that provides commonly used voltages of plus or minus 12 Volts from an unregulated dc source of from 14 to 40 Volts. Unique features of converter are its high efficiency at low power level and ability to provide output either larger or smaller than input voltage.

  12. Digital Control Technologies for Modular DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon

    2002-01-01

    Recent trends in aerospace Power Management and Distribution (PMAD) systems focus on using commercial off-the-shelf (COTS) components as standard building blocks. This move to more modular designs has been driven by a desire to reduce costs and development times, but is also due to the impressive power density and efficiency numbers achieved by today's commercial DC-DC converters. However, the PMAD designer quickly learns of the hidden "costs" of using COTS converters. The most significant cost is the required addition of external input filters to meet strict electromagnetic interference (MIAMI) requirements for space systems. In fact, the high power density numbers achieved by the commercial manufacturers are greatly due to the lack of necessary input filters included in the COTS module. The NASA Glenn Research Center is currently pursuing a digital control technology that addresses this problem with modular DC-DC converters. This paper presents the digital control technologies that have been developed to greatly reduce the input filter requirements for paralleled, modular DC-DC converters. Initial test result show that the input filter's inductor size was reduced by 75 percent, and the capacitor size was reduced by 94 percent while maintaining the same power quality specifications.

  13. Analysis of a dc bus system with a nonlinear constant power load and its delayed feedback control.

    PubMed

    Konishi, Keiji; Sugitani, Yoshiki; Hara, Naoyuki

    2014-02-01

    This paper tackles a destabilizing problem of a direct-current (dc) bus system with constant power loads, which can be considered a fundamental problem of dc power grid networks. The present paper clarifies scenarios of the destabilization and applies the well-known delayed-feedback control to the stabilization of the destabilized bus system on the basis of nonlinear science. Further, we propose a systematic procedure for designing the delayed feedback controller. This controller can converge the bus voltage exactly on an unstable operating point without accurate information and can track it using tiny control energy even when a system parameter, such as the power consumption of the load, is slowly varied. These features demonstrate that delayed feedback control can be considered a strong candidate for solving the destabilizing problem.

  14. Analysis of a dc bus system with a nonlinear constant power load and its delayed feedback control.

    PubMed

    Konishi, Keiji; Sugitani, Yoshiki; Hara, Naoyuki

    2014-02-01

    This paper tackles a destabilizing problem of a direct-current (dc) bus system with constant power loads, which can be considered a fundamental problem of dc power grid networks. The present paper clarifies scenarios of the destabilization and applies the well-known delayed-feedback control to the stabilization of the destabilized bus system on the basis of nonlinear science. Further, we propose a systematic procedure for designing the delayed feedback controller. This controller can converge the bus voltage exactly on an unstable operating point without accurate information and can track it using tiny control energy even when a system parameter, such as the power consumption of the load, is slowly varied. These features demonstrate that delayed feedback control can be considered a strong candidate for solving the destabilizing problem. PMID:25353544

  15. Low power low temperature poly-Si thin-film transistor shift register with DC-type output driver

    NASA Astrophysics Data System (ADS)

    Song, Seok-Jeong; Kim, Byung Hoon; Jang, Jin; Nam, Hyoungsik

    2015-09-01

    This paper demonstrates a low power DC-type low temperature poly-Si (LTPS) thin-film transistor (TFT) shift register that consists of nine TFTs and one bootstrapping capacitor. The proposed circuit connects large size pull-up TFTs of output drivers to positive supply instead of alternating clock signals in order to reduce substantially the power consumption of clock drivers. The SPICE simulation ensures that the variable overlap intervals can be programmed by the delay between clock signals and the overall power consumption of a DC-type circuit can be reduced to 45% of an AC-type one for a full-HD display. The operation of a proposed structure is also verified with a fabricated 16-stage gate driver.

  16. Electrical power systems for distributed generation

    SciTech Connect

    Robertson, T.A.; Huval, S.J.

    1996-12-31

    {open_quotes}Distributed Generation{close_quotes} has become the {open_quotes}buzz{close_quotes} word of an electric utility industry facing deregulation. Many industrial facilities utilize equipment in distributed installations to serve the needs of a thermal host through the capture of exhaust energy in a heat recovery steam generator. The electrical power generated is then sold as a {open_quotes}side benefit{close_quotes} to the cost-effective supply of high quality thermal energy. Distributed generation is desirable for many different reasons, each with unique characteristics of the product. Many years of experience in the distributed generation market has helped Stewart & Stevenson to define a range of product features that are crucial to most any application. The following paper will highlight a few of these applications. The paper will also examine the range of products currently available and in development. Finally, we will survey the additional services offered by Stewart & Stevenson to meet the needs of a rapidly changing power generation industry.

  17. Description of real-time Ada software implementation of a power system monitor for the Space Station Freedom PMAD DC testbed

    NASA Technical Reports Server (NTRS)

    Ludwig, Kimberly; Mackin, Michael; Wright, Theodore

    1991-01-01

    The Ada language software development to perform the electrical system monitoring functions for the NASA Lewis Research Center's Power Management and Distribution (PMAD) DC testbed is described. The results of the effort to implement this monitor are presented. The PMAD DC testbed is a reduced-scale prototype of the electrical power system to be used in the Space Station Freedom. The power is controlled by smart switches known as power control components (or switchgear). The power control components are currently coordinated by five Compaq 382/20e computers connected through an 802.4 local area network. One of these computers is designated as the control node with the other four acting as subsidiary controllers. The subsidiary controllers are connected to the power control components with a Mil-Std-1553 network. An operator interface is supplied by adding a sixth computer. The power system monitor algorithm is comprised of several functions including: periodic data acquisition, data smoothing, system performance analysis, and status reporting. Data is collected from the switchgear sensors every 100 milliseconds, then passed through a 2 Hz digital filter. System performance analysis includes power interruption and overcurrent detection. The reporting mechanism notifies an operator of any abnormalities in the system. Once per second, the system monitor provides data to the control node for further processing, such as state estimation. The system monitor required a hardware time interrupt to activate the data acquisition function. The execution time of the code was optimized using an assembly language routine. The routine allows direct vectoring of the processor to Ada language procedures that perform periodic control activities. A summary of the advantages and side effects of this technique are discussed.

  18. Independent Orbiter Assessment (IOA): Analysis of the Electrical Power Distribution and Control Subsystem, Volume 2

    NASA Technical Reports Server (NTRS)

    Schmeckpeper, K. R.

    1987-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Electrical Power Distribution and Control (EPD and C) hardware. The EPD and C hardware performs the functions of distributing, sensing, and controlling 28 volt DC power and of inverting, distributing, sensing, and controlling 117 volt 400 Hz AC power to all Orbiter subsystems from the three fuel cells in the Electrical Power Generation (EPG) subsystem. Volume 2 continues the presentation of IOA analysis worksheets and contains the potential critical items list.

  19. Pulse doubling in zigzag-connected autotransformer-based 12-pulse ac-dc converter for power quality improvement

    NASA Astrophysics Data System (ADS)

    Abdollahi, Rohollah

    2012-12-01

    This paper presents a pulse doubling technique in a 12-pulse ac-dc converter which supplies direct torque controlled motor drives (DTCIMDs) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant changes in the installations and yields in harmonic reduction in both ac and dc sides. The 12-pulse rectified output voltage is accomplished via two paralleled six-pulse acdc converters each of them consisting of three-phase diode bridge rectifiers. An autotransformer is designed to supply the rectifiers. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. Independent operation of paralleled diode-bridge rectifiers, i.e. dc-ripple re-injection methodology, requires a Zero Sequence Blocking Transformer (ZSBT). Finally, a tapped interphase reactor is connected at the output of ZSBT to double the pulse numbers of output voltage up to 24 pulses. The aforementioned structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse, 12-pulse, and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 5% for the proposed topology at various loads.

  20. A Novel Soft Switching PWM Power Frequency Converter with Non DC Smoothing Filter Link for Consumer High Frequency Induction Heating

    NASA Astrophysics Data System (ADS)

    Sugimura, Hisayuki; Muraoka, Hidekazu; Hiraki, Eiji; Hirota, Izuo; Yasui, Kenji; Omori, Hideki; Lee, Hyun-Woo; Nakaoka, Mutsuo

    In this paper, high frequency power converter without DC smoothing electrolytic capacitor filter link which convert the 100V/200Vrms and 60Hz single phase utility frequency AC power into a high frequency AC. This proposed high frequency AC power converter without electrolytic capacitor filter can operate under a principle of soft switching PWM based on a lossless capacitor snubber is proposed and demonstrated for consumer high frequency induction heating (IH). In particular, this high frequency power converter capable of producing a high frequency AC more than 20kHz is developed for consumer IH applications as hot water producer and steamer based on the specially designed spiral type IH-Dual Packs Heater (DPH), which includes the dual mode pulse modulation control scheme based on soft switching PWM for high output power setting and commercial frequency AC zero voltage soft switching pulse density modulation (PDM) for low output power settings. This developed high frequency power frequency converter using trench gate IGBTs is clarified on the basis of experimental and simulation results for its circuit operation of the utility frequency AC to high frequency AC frequency PWM power converter without the electrolytic capacitor bank DC filter link for the IH hot water and IH steamer. These IH appliances are based upon an innovative electromagnetic IH-DPH for fluid heating as heat exchanger in consumer pipeline. Finally, its power regulation characteristics, power conversion efficiency and harmonic current components characteristics including power factor in utility AC grid side are evaluated and discussed from an experimental point of view. The practical effectiveness of this utility frequency AC to high frequency AC soft switching high power frequency converter defined conveniently as high frequency soft switching cyclo-inverter is proved as one of the important products effective for next generation IH application all electricity power utilizations.

  1. Design of a power management and distribution system for a thermionic-diode powered spacecraft

    NASA Technical Reports Server (NTRS)

    Kimnach, Greg L.

    1996-01-01

    The Electrical Systems Development Branch of the Power Technology Division at the NASA Lewis Research Center in Cleveland, Ohio is designing a Power Management and Distribution (PMAD) System for the Air Force's Integrated Solar Upper Stage (ISUS) Engine Ground Test Demonstration (EGD). The ISUS program uses solar-thermal propulsion to perform orbit transfers from Low Earth Orbit (LEO) to Geosynchronous Orbit (GEO) and from LEO to Molnya. The ISUS uses the same energy conversion receiver to perform the LEO to High Earth Orbit (HEO) transfer and to generate on-orbit electric power for the payloads. On-orbit power generation is accomplished via two solar concentrators heating a dual-cavity graphite-core which has Thermionic Diodes (TMD's) encircling each cavity. The graphite core and concentrators together are called the Receiver and Concentrator (RAC). The TDM-emitters reach peak temperatures of approximately 2200K, and the TID-collectors are run at approximately 1000K. Because of the high Specific Impulse (I(sup sp)) of solar thermal propulsion relative to chemical propulsion, and because a common bus is used for communications, GN&C, power, etc., a substantial increase in payload weight is possible. This potentially allows for a stepdown in the required launch vehicle size or class for similar payload weight using conventional chemical propulsion and a separate spacecraft bus. The ISUS power system is to provide 1000W(sub e) at 28+/-6V(sub dc) to the payload/spacecraft from a maximum TID generation capability of 1070W(sub e) at 2200K. Producing power with this quality, protecting the spacecraft from electrical faults and accommodating operational constraints of the TID's are the responsibilities of the PMAD system. The design strategy and system options examined along with the proposed designs for the Flight and EGD configurations are discussed herein.

  2. Self-stabilization techniques for intermediate power level in stacked-Vdd integrated circuits using DC-balanced coding methods

    NASA Astrophysics Data System (ADS)

    Kohara, Yusuke; Kubo, Naoya; Nishiyama, Tomofumi; Koizuka, Taiki; Alimudin, Mohammad; Rahmat, Amirul; Okamura, Hitoshi; Yamanokuchi, Tomoyuki; Nakamura, Kazuyuki

    2016-04-01

    Two new parallel bus coding methods for generating a DC-balanced code with additional bits are proposed to achieve the self-stabilization of the intermediate power level in Stacked-Vdd integrated circuits. They contribute to producing a uniform switching current in parallel inputs and outputs (I/Os). Type I coding minimizes the difference in the number of switchings between the upper and lower CMOS I/Os by 8B/10B coding followed by toggle conversion. Type II coding, in which the multi-value running disparity control feature is integrated into the bus-invert coding, requires only one redundant bit for any wider bus. Their DC-balanced feature and the stability effect of the intermediate power level in the Stacked-Vdd structure were experimentally confirmed from the measurement results obtained from the developed test chips.

  3. Multi-channel Data Acquisition System for a 500 m DC HTS Power Cable in Ishikari

    NASA Astrophysics Data System (ADS)

    Ivanov, Yury V.; Chikumoto, Noriko; Watanabe, Hirofumi; Takano, Hirohisa; Inoue, Noriyuki; Yamaguchi, Satarou

    Reduction of heat penetrating into the cryogenic region is the important method of optimization of superconducting devices. In the cases of short-range power transmission lines and compact HTS devices like magnets, the heat leakage through current leads is relatively large. In order to decrease this contribution, current leads equipped with Peltier elements can be used. The mentioned technology is being actively developed in the Chubu University. Commercial samples of Peltier current leads are installed at the terminals of 500-meter DC HTS cable in Ishikari (Hokkaido). This cable is designed for 5 kA. The inner conducting layer consists of 37 DI-BSCCO HTS tapes from Sumitomo Electric Industries, Ltd. with a critical current of 180 A; and the outer one consists of 35 tapes of the same type. Each end of the cable's tape is connected to the individual Peltier current lead. Accordingly, each of the two terminals is equipped with 72 Peltier current leads, 144 pieces in total. In order to examine behavior of the current leads in detail, each piece is supplied with two thermocouples; there are also voltage taps on feedthrough and on HTS tape end. In addition, current through Peltier current lead can be measured by means of individual current transformer. The hardware part of the data acquisition system includes four Keithley 3706A multimeters equipped with 60-channel model 3724 FET multiplexer cards. Therefore, 144 data blocks are formed. Furthermore, there are 72 measurements of a voltage drop across HTS tape. Sampling period is set to be 3 s. The program part of the data acquisition system was written using LabVIEW software solution (National Instruments Corp.).

  4. Structure Learning in Power Distribution Networks

    SciTech Connect

    Deka, Deepjyoti; Chertkov, Michael; Backhaus, Scott N.

    2015-01-13

    Traditionally power distribution networks are either not observable or only partially observable. This complicates development and implementation of new smart grid technologies, such as these related to demand response, outage detection and management, and improved load-monitoring. Here, inspired by proliferation of the metering technology, we discuss statistical estimation problems in structurally loopy but operationally radial distribution grids consisting in learning operational layout of the network from measurements, e.g. voltage data, which are either already available or can be made available with a relatively minor investment. Our newly suggested algorithms apply to a wide range of realistic scenarios. The algorithms are also computationally efficient – polynomial in time – which is proven theoretically and illustrated computationally on a number of test cases. The technique developed can be applied to detect line failures in real time as well as to understand the scope of possible adversarial attacks on the grid.

  5. Space Station module Power Management And Distribution (PMAD) system

    NASA Technical Reports Server (NTRS)

    Walls, Bryan

    1990-01-01

    This project consists of several tasks which are unified toward experimentally demonstrating the operation of a highly autonomous, user-supportive power management and distribution system for Space Station Freedom (SSF) habitation/laboratory modules. This goal will be extended to a demonstration of autonomous, cooperative power system operation for the whole SSF power system through a joint effort with NASA's Lewis Research Center, using their Autonomous Power System. Short term goals for the space station module power management and distribution include having an operational breadboard reflecting current plans for SSF, improving performance of the system communications, and improving the organization and mutability of the artificial intelligence (AI) systems. In the middle term, intermediate levels of autonomy will be added, user interfaces will be modified, and enhanced modeling capabilities will be integrated in the system. Long term goals involve conversion of all software into Ada, vigorous verification and validation efforts and, finally, seeing an impact of this research on the operation of SSF. Conversion of the system to a DC Star configuration is now in progress, and should be completed by the end of October, 1989. This configuration reflects the latest SSF module architecture. Hardware is now being procured which will improve system communications significantly. The Knowledge-Based Management System (KBMS) is initially developed and the rules from FRAMES have been implemented in the KBMS. Rules in the other two AI systems are also being grouped modularly, making them more tractable, and easier to eventually move into the KBMS. Adding an intermediate level of autonomy will require development of a planning utility, which will also be built using the KBMS. These changes will require having the user interface for the whole system available from one interface. An Enhanced Model will be developed, which will allow exercise of the system through the interface

  6. Optical Investigations of Dust Particles Distribution in RF and DC Discharges

    SciTech Connect

    Ramazanov, T. S.; Dosbolayev, M. K.; Jumabekov, A. N.; Amangaliyeva, R. Zh.; Filatova, I. I.; Azharonok, V. V.

    2008-09-07

    Optical emission spectroscopy is used to study dust particles movement and conditions of a formation of ordered plasma-dust structures in a capacitively coupled RF discharge. 3D binocular diagnostics of plasma-dust structures in dc discharge was made.

  7. Time-Dependent Distribution Functions in C-Mod Calculated with the CQL3D-Hybrid-FOW, AORSA Full-Wave, and DC Lorentz Codes

    NASA Astrophysics Data System (ADS)

    Harvey, R. W. (Bob); Petrov, Yu. V.; Jaeger, E. F.; Berry, L. A.; Bonoli, P. T.; Bader, A.

    2015-11-01

    A time-dependent simulation of C-Mod pulsed ICRF power is made calculating minority hydrogen ion distribution functions with the CQL3D-Hybrid-FOW finite-orbit-width Fokker-Planck code. ICRF fields are calculated with the AORSA full wave code, and RF diffusion coefficients are obtained from these fields using the DC Lorentz gyro-orbit code. Prior results with a zero-banana-width simulation using the CQL3D/AORSA/DC time-cycles showed a pronounced enhancement of the H distribution in the perpendicular velocity direction compared to results obtained from Stix's quasilinear theory, in general agreement with experiment. The present study compares the new FOW results, including relevant gyro-radius effects, to determine the importance of these effects on the the NPA synthetic diagnostic time-dependence. The new NPA results give increased agreement with experiment, particularly in the ramp-down time after the ICRF pulse. Funded, through subcontract with Massachusetts Institute of Technology, by USDOE sponsored SciDAC Center for Simulation of Wave-Plasma Interactions.

  8. Test report light duty utility arm power distribution system (PDS)

    SciTech Connect

    Clark, D.A.

    1996-03-04

    The Light Duty Utility Arm (LDUA) Power Distribution System has completed vendor and post-delivery acceptance testing. The Power Distribution System has been found to be acceptable and is now ready for integration with the overall LDUA system.

  9. Magnetohydrodynamic electromagnetic pulse (MHD-EMP) interaction with power transmission and distribution systems

    SciTech Connect

    Tesche, F.M. , Dallas, TX ); Barnes, P.R. ); Meliopoulos, A.P.S. . Dept. of Electrical Engineering)

    1992-02-01

    This report discusses the effects of the late-time high-altitude electromagnetic pulse (HEMP) on electrical transmission and distribution (T D) systems. This environment, known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), is a very slowly varying electric field induced in the earth's surface, similar to the field induced by a geomagnetic storm. It can result in the flow of a quasi-dc current in grounded power lines and in the subsequent magnetic saturation of transformers. This saturation, in turn, causes 6-Hz harmonic distortion and an increase in the reactive power required by generation facilities. This report analyzes and discusses these phenomena. The MHD-EMP environment is briefly discussed, and a simplified form of the earth-induced electric field is developed for use in a parametric study of transmission line responses. Various field coupling models are described, and calculated results for the responses of both transmission- and distribution-class power lines are presented. These calculated responses are compared with measurements of transformer operation under dc excitation to infer the MHD-EMP response of these power system components. It is found that the MHD-EMP environment would have a marked effect on a power system by inducing up to several hundreds of amperes of quasi-dc current on power lines. These currents will cause transformers to saturate which could result in excessive harmonic generation, voltage swings, and voltage suppression. The design of critical facilities which are required to operate during and after MHD-EMP events will have to be modified in order to mitigate the effects of these abnormal power system conditions.

  10. Magnetohydrodynamic electromagnetic pulse (MHD-EMP) interaction with power transmission and distribution systems

    SciTech Connect

    Tesche, F.M.; Barnes, P.R.; Meliopoulos, A.P.S.

    1992-02-01

    This report discusses the effects of the late-time high-altitude electromagnetic pulse (HEMP) on electrical transmission and distribution (T&D) systems. This environment, known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), is a very slowly varying electric field induced in the earth`s surface, similar to the field induced by a geomagnetic storm. It can result in the flow of a quasi-dc current in grounded power lines and in the subsequent magnetic saturation of transformers. This saturation, in turn, causes 6-Hz harmonic distortion and an increase in the reactive power required by generation facilities. This report analyzes and discusses these phenomena. The MHD-EMP environment is briefly discussed, and a simplified form of the earth-induced electric field is developed for use in a parametric study of transmission line responses. Various field coupling models are described, and calculated results for the responses of both transmission- and distribution-class power lines are presented. These calculated responses are compared with measurements of transformer operation under dc excitation to infer the MHD-EMP response of these power system components. It is found that the MHD-EMP environment would have a marked effect on a power system by inducing up to several hundreds of amperes of quasi-dc current on power lines. These currents will cause transformers to saturate which could result in excessive harmonic generation, voltage swings, and voltage suppression. The design of critical facilities which are required to operate during and after MHD-EMP events will have to be modified in order to mitigate the effects of these abnormal power system conditions.

  11. 80 MeV C6+ ion irradiation effects on the DC electrical characteristics of silicon NPN power transistors

    NASA Astrophysics Data System (ADS)

    Bharathi, M. N.; Pushpa, N.; Vinayakprasanna, N. H.; Prakash, A. P. Gnana

    2016-05-01

    The total dose effects of 80 MeV C6+ ions on the DC electrical characteristics of Silicon NPN rf power transistors have been studied in the dose range of 100 krad to 100 Mrad. The SRIM simulation was used to understand the energy loss and range of the ions in the transistor structure. The different electrical parameters such as Gummel characteristics, excess base current (ΔIB = IBpost - IBpre), dc forward current gain (hFE), transconductance (gm), displacement damage factor (K) and output characteristics (VCE-IC) were studied systematically before and after irradiation. The significant degradation in base current (IB) and hFE was observed after irradiation. Isochronal annealing study was conducted on the irradiated transistors to analyze the recovery in different electrical parameters. These results were compared with 60C0 gamma irradiation results in the same dose range.

  12. Satellite control of electric power distribution

    NASA Technical Reports Server (NTRS)

    Bergen, L.

    1981-01-01

    An L-band frequencies satellite link providing the medium for direct control of electrical loads at individual customer sites from remote central locations is described. All loads supplied under interruptible-service contracts are likely condidates for such control, and they can be cycled or switched off to reduce system loads. For every kW of load eliminated or deferred to off-peak hours, the power company reduces its need for additional generating capacity. In addition, the satellite could switch meter registers so that their readings automatically reflected the time of consumption. The system would perform load-shedding operations during emergencies, disconnecting large blocks of load according to predetermined priorities. Among the distribution operations conducted by the satellite in real time would be: load reconfiguration, voltage regulation, fault isolation, and capacitor and feeder load control.

  13. Power System Concepts for the Lunar Outpost: A Review of the Power Generation, Energy Storage, Power Management and Distribution (PMAD) System Requirements and Potential Technologies for Development of the Lunar Outpost

    NASA Technical Reports Server (NTRS)

    Khan, Z.; Vranis, A.; Zavoico, A.; Freid, S.; Manners, B.

    2006-01-01

    This paper will review potential power system concepts for the development of the lunar outpost including power generation, energy storage, and power management and distribution (PMAD). In particular, the requirements of the initial robotic missions will be discussed and the technologies considered will include cryogenics and regenerative fuel cells (RFC), AC and DC transmission line technology, high voltage and low voltage power transmission, conductor materials of construction and power beaming concepts for transmitting power to difficult to access locations such as at the bottom of craters. Operating conditions, component characteristics, reliability, maintainability, constructability, system safety, technology gaps/risk and adaptability for future lunar missions will be discussed for the technologies considered.

  14. Remote sensing of cloud droplet size distributions in DC3 with the UMBC-LACO Rainbow Polarimetric Imager (RPI)

    NASA Astrophysics Data System (ADS)

    Buczkowski, S.; Martins, J.; Fernandez-Borda, R.; Cieslak, D.; Hall, J.

    2013-12-01

    The UMBC Rainbow Polarimetric Imager is a small form factor VIS imaging polarimeter suitable for use on a number of platforms. An optical system based on a Phillips prism with three Bayer filter color detectors, each detecting a separate polarization state, allows simultaneous detection of polarization and spectral information. A Mueller matrix-like calibration scheme corrects for polarization artifacts in the optical train and allows retrieval of the polarization state of incoming light to better than 0.5%. Coupled with wide field of view optics (~90°), RPI can capture images of cloudbows over a wide range of aircraft headings and solar zenith angles for retrieval of cloud droplet size distribution (DSD) parameters. In May-June 2012, RPI was flown in a nadir port on the NASA DC-8 during the DC3 field campaign. We will show examples of cloudbow DSD parameter retrievals from the campaign to demonstrate the efficacy of such a system to terrestrial atmospheric remote sensing. RPI image from DC3 06/15/2012 flight. Left panel is raw image from the RPI 90° camera. Middle panel is Stokes 'q' parameter retrieved from full three camera dataset. Right panel is a horizontal cut in 'q' through the glory. Both middle and right panels clearly show cloudbow features which can be fit to infer cloud DSD parameters.

  15. A method for reduction of cogging torque in brushless DC motor considering the distribution of magnetization by 3DEMCN

    SciTech Connect

    Hur, J.; Hyun, D.S.; Hong, J.P.

    1998-09-01

    The method of reducing cogging torque and improving average torque has been studied by changing the dead zone angle of trapezoidal magnetization distribution of ring type rotor magnet in brushless DC motor (BLDCM). Because BLDCM has 3-D shape of overhang, 3-D analysis should be used for exact computation of its magnetic field. 3-D equivalent magnetic circuit network method (3-D EMCN) which can analyze an accurate 3-D magnetic field has been introduced. The analysis results of cogging torque using 3-D EMCN are compared with ones of 3-D finite element method (3-D FEM) and experimental data.

  16. An improved AVC strategy applied in distributed wind power system

    NASA Astrophysics Data System (ADS)

    Zhao, Y. N.; Liu, Q. H.; Song, S. Y.; Mao, W.

    2016-08-01

    Traditional AVC strategy is mainly used in wind farm and only concerns about grid connection point, which is not suitable for distributed wind power system. Therefore, this paper comes up with an improved AVC strategy applied in distributed wind power system. The strategy takes all nodes of distribution network into consideration and chooses the node having the most serious voltage deviation as control point to calculate the reactive power reference. In addition, distribution principles can be divided into two conditions: when wind generators access to network on single node, the reactive power reference is distributed according to reactive power capacity; when wind generators access to network on multi-node, the reference is distributed according to sensitivity. Simulation results show the correctness and reliability of the strategy. Compared with traditional control strategy, the strategy described in this paper can make full use of generators reactive power output ability according to the distribution network voltage condition and improve the distribution network voltage level effectively.

  17. A new rectenna circuit using a bow-tie antenna for the conversion of microwave power to dc power

    NASA Technical Reports Server (NTRS)

    Tran, Michael; Nguyen, Cam

    1993-01-01

    The novel rectenna circuit presented, which integrated a bowtie antenna with a diode, is capable of broadband, high-efficiency operation, and is insensitive to incident field angle. The device is noted, moreover, to behave as a lowpass filter for dc output. For 2.45 GHz operation, a 79-percent conversion efficiency has been demonstrated.

  18. Mapping Power Law Distributions in Digital Health Social Networks: Methods, Interpretations, and Practical Implications

    PubMed Central

    2015-01-01

    Background Social networks are common in digital health. A new stream of research is beginning to investigate the mechanisms of digital health social networks (DHSNs), how they are structured, how they function, and how their growth can be nurtured and managed. DHSNs increase in value when additional content is added, and the structure of networks may resemble the characteristics of power laws. Power laws are contrary to traditional Gaussian averages in that they demonstrate correlated phenomena. Objectives The objective of this study is to investigate whether the distribution frequency in four DHSNs can be characterized as following a power law. A second objective is to describe the method used to determine the comparison. Methods Data from four DHSNs—Alcohol Help Center (AHC), Depression Center (DC), Panic Center (PC), and Stop Smoking Center (SSC)—were compared to power law distributions. To assist future researchers and managers, the 5-step methodology used to analyze and compare datasets is described. Results All four DHSNs were found to have right-skewed distributions, indicating the data were not normally distributed. When power trend lines were added to each frequency distribution, R 2 values indicated that, to a very high degree, the variance in post frequencies can be explained by actor rank (AHC .962, DC .975, PC .969, SSC .95). Spearman correlations provided further indication of the strength and statistical significance of the relationship (AHC .987. DC .967, PC .983, SSC .993, P<.001). Conclusions This is the first study to investigate power distributions across multiple DHSNs, each addressing a unique condition. Results indicate that despite vast differences in theme, content, and length of existence, DHSNs follow properties of power laws. The structure of DHSNs is important as it gives insight to researchers and managers into the nature and mechanisms of network functionality. The 5-step process undertaken to compare actor contribution patterns

  19. Relationships among classes of self-oscillating transistor parallel inverters. [dc to square wave converter circuits for power conditioning

    NASA Technical Reports Server (NTRS)

    Wilson, T. G.; Lee, F. C. Y.; Burns, W. W., III; Owen, H. A., Jr.

    1974-01-01

    A procedure is developed for classifying dc-to-square-wave two-transistor parallel inverters used in power conditioning applications. The inverters are reduced to equivalent RLC networks and are then grouped with other inverters with the same basic equivalent circuit. Distinction between inverter classes is based on the topology characteristics of the equivalent circuits. Information about one class can then be extended to another class using the basic oscillation theory and the concept of duality. Oscillograms from test circuits confirm the validity of the procedure adopted.

  20. Design note about a 75 KVA quiet power distribution system

    SciTech Connect

    Visser, A.T.

    1984-04-05

    This note describes a 75KVA quiet power distribution system for X 653 in neutrino Lab D. It is fed from the regular AC distribution which exists in the building and it has no standby power. Its purpose is to remove electrical disturbances which are present on the regular AC distribution.

  1. Power-Law Distributions Based on Exponential Distributions: Latent Scaling, Spurious Zipf's Law, and Fractal Rabbits

    NASA Astrophysics Data System (ADS)

    Chen, Yanguang

    2015-03-01

    The difference between the inverse power function and the negative exponential function is significant. The former suggests a complex distribution, while the latter indicates a simple distribution. However, the association of the power-law distribution with the exponential distribution has been seldom researched. This paper is devoted to exploring the relationships between exponential laws and power laws from the angle of view of urban geography. Using mathematical derivation and numerical experiments, I reveal that a power-law distribution can be created through a semi-moving average process of an exponential distribution. For the distributions defined in a one-dimension space (e.g. Zipf's law), the power exponent is 1; while for those defined in a two-dimension space (e.g. Clark's law), the power exponent is 2. The findings of this study are as follows. First, the exponential distributions suggest a hidden scaling, but the scaling exponents suggest a Euclidean dimension. Second, special power-law distributions can be derived from exponential distributions, but they differ from the typical power-law distributions. Third, it is the real power-law distributions that can be related with fractal dimension. This study discloses an inherent link between simplicity and complexity. In practice, maybe the result presented in this paper can be employed to distinguish the real power laws from spurious power laws (e.g. the fake Zipf distribution).

  2. Experimental determination of the MHD-EMP effects on power distribution transformers

    SciTech Connect

    McConnell, B.W.; Barnes, P.R. ); Tesche, F.M. , Dallas, TX )

    1991-01-01

    It is a well-established fact that geomagnetic storms influence electrical power transmission and distribution systems. Previous cases of such storms in the northern latitudes have resulted in occasional power disruptions, and in some cases, damage to transformers. These effects are caused by a time variation of the earth's magnetic field creating an induced electric field along the surface of the earth. This E-field acts as a voltage source along long power transmission or distribution lines, and if the line is connected to the earth at both ends, a quasi-dc current can flow. This current can cause unwanted saturation in the magnetic cores of transformers in the power system, and this, in turn produces harmonic distortion and transformer heating. This can lead to system upset (shutdown) and possibly transformer burn-out. The detonation of a high altitude nuclear explosion is also known to affect the magnetosphere, producing late-time variations of the earth's magnetic field for several hundreds of seconds. Known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), or E{sub 3}, this environment is of particular concern to electrical power systems in the event of a nuclear attack. Although the MHD-EMP induced currents can be significantly larger in magnitude, they last for a shorter period of time than do those from a geomagnetic storm. The effect of this environment compounds the adverse effects of the early-time high altitude EMP (HEMP) environment, posing a potentially serious threat to the electrical system. The present paper documents an experimental program designed to better understand the behavior of distribution-class transformers subjected to quasi-dc current excitation. Given the knowledge of the MHD-EMP-induced current flowing in a long power line, and the transformer response characteristics obtained in this program, it will be possible to make more accurate assessments of the behavior of the overall power system to EMP. 7 refs., 5 figs.

  3. Automation in the Space Station module power management and distribution Breadboard

    NASA Technical Reports Server (NTRS)

    Walls, Bryan; Lollar, Louis F.

    1990-01-01

    The Space Station Module Power Management and Distribution (SSM/PMAD) Breadboard, located at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, models the power distribution within a Space Station Freedom Habitation or Laboratory module. Originally designed for 20 kHz ac power, the system is now being converted to high voltage dc power with power levels on a par with those expected for a space station module. In addition to the power distribution hardware, the system includes computer control through a hierarchy of processes. The lowest level process consists of fast, simple (from a computing standpoint) switchgear, capable of quickly safing the system. The next level consists of local load center processors called Lowest Level Processors (LLP's). These LLP's execute load scheduling, perform redundant switching, and shed loads which use more than scheduled power. The level above the LLP's contains a Communication and Algorithmic Controller (CAC) which coordinates communications with the highest level. Finally, at this highest level, three cooperating Artificial Intelligence (AI) systems manage load prioritization, load scheduling, load shedding, and fault recovery and management. The system provides an excellent venue for developing and examining advanced automation techniques. The current system and the plans for its future are examined.

  4. Developments in space power components for power management and distribution

    NASA Technical Reports Server (NTRS)

    Renz, D. D.

    1984-01-01

    Advanced power electronic components development for space applications is discussed. The components described include transformers, inductors, semiconductor devices such as transistors and diodes, remote power controllers, and transmission lines.

  5. Intelligent dc-dc Converter Technology Developed and Tested

    NASA Technical Reports Server (NTRS)

    Button, Robert M.

    2001-01-01

    The NASA Glenn Research Center and the Cleveland State University have developed a digitally controlled dc-dc converter to research the benefits of flexible, digital control on power electronics and systems. Initial research and testing has shown that conventional dc-dc converters can benefit from improved performance by using digital-signal processors and nonlinear control algorithms.

  6. Fuel Cycle Comparison for Distributed Power Technologies

    SciTech Connect

    Elgowainy, A.; Wang, M. Q.

    2008-11-15

    This report examines backup power and prime power systems and addresses the potential energy and environmental effects of substituting fuel cells for existing combustion technologies based on microturbines and internal combustion engines.

  7. DC/DC Converter Stability Testing Study

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2008-01-01

    This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop oscillation. In particular, certain channel power levels of converter input noises have been found to have high degree correlation with the gain/phase margins. It becomes a potential new method to evaluate stability levels of all type of DC/DC converters by utilizing the spectral analysis on converter input noises.

  8. Point-Focusing Solar-Power Distributed Receivers

    NASA Technical Reports Server (NTRS)

    Lucas, J. W.

    1985-01-01

    Two-volume annual report describes development work aimed at achieving large-scale production of modular, point-focusing distributed receivers (PFDR's) for solar-powered generation of electricity or thermal power for industrial use.

  9. Distributed energy store powered railguns for hypervelocity launch

    NASA Astrophysics Data System (ADS)

    Maas, Brian L.; Bauer, David P.; Marshall, Richard A.

    1993-01-01

    Highly distributed power supplies are proposed as a basis for current difficulties with hypervelocity railgun power-supply compactness. This distributed power supply configuration reduces rail-to-rail voltage behind the main armature, thereby reducing the tendency for secondary armature current formation; secondary current elimination is essential for achieving the efficiencies associated with muzzle velocity above 6 km/sec. Attention is given to analytical and experimental results for two distributed energy storage schemes.

  10. Study on AC-DC Electrical Conductivities in Warm Dense Matter Generated by Pulsed-power Discharge with Isochoric Vessel

    NASA Astrophysics Data System (ADS)

    Sasaki, Toru; Ohuchi, Takumi; Takahashi, Takuya; Kawaguchi, Yoshinari; Saito, Hirotaka; Miki, Yasutoshi; Takahashi, Kazumasa; Kikuchi, Takashi; Aso, Tsukasa; Harada, Nob.

    2016-03-01

    To observe AC and DC electrical conductivity in warm dense matter (WDM), we have demonstrated to apply the spectroscopic ellipsometry for a pulsed-power discharge with isochoric vessel. At 10 μs from the beginning of discharge, the generated parameters by using pulsed-power discharge with isochoric vessel are 0.1 ρ s (ρ s: solid density) of density and 4000 K of temperature, respectively. The DC electrical conductivity for above parameters is estimated to be 104 S/m. In order to measure the AC electrical conductivity, we have developed a four-detector spectroscopic ellipsometer with a multichannel spectrometer. The multichannel spectrometer, in which consists of a 16-channel photodiode array, a two-stages voltage adder, and a flat diffraction grating, has 10 MHz of the frequency response with covered visible spectrum. For applying the four-detector spectroscopic ellipsometer, we observe the each observation signal evolves the polarized behavior compared to the ratio as I 1/I 2.

  11. DC source assemblies

    DOEpatents

    Campbell, Jeremy B; Newson, Steve

    2013-02-26

    Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

  12. Electrical and thermal characterization of a novel high pressure gas cooled DC power cable

    NASA Astrophysics Data System (ADS)

    Rodrigo, H.; Salmhofer, F.; Kwag, D. S.; Pamidi, S.; Graber, L.; Crook, D. G.; Ranner, S. L.; Dale, S. J.; Knoll, D.

    2012-04-01

    High-temperature superconductors (HTS) allow power cables of substantially higher current density than conventional copper or aluminum cables. This is important for applications where a low mass and a low volume are critical such as naval, aeronautical and space applications. The novel type of cable under consideration is cooled by gaseous Helium at elevated pressure. Helium is known for having poor electric breakdown strength; therefore the dielectric capabilities of this type of cable must be tested under conditions similar to the envisaged operation. In order to study the dielectric performance we have designed and built a novel high pressure cryostat rated at 2.17 MPa which has been used for testing model cables of lengths of up to 1 m. The cryostat is an open system where the gas is not re-circulated. This allows maintaining a high purity of the gas. The target temperature range is between 40 K and 70 K. This substantially increases the critical current density of the HTS compared to 77 K, which is the typical temperature of cables cooled by liquid Nitrogen. The cryostat presented allows for adjusting the temperature and keeping it constant for the time necessary to run a complete dielectric characterization test. We give a detailed description of the cryostat. Measurements of partial discharge inception voltages as well as the temperature distribution along the model cables as a function of time are presented. Tests showed that the thermal insulation characteristics of this cryostat were sufficient for the dielectric tests of up to 1 h duration. The partial discharge inception voltage (PDIV) of the high voltage bushing was about 16 kV. These values are well within our design requirements.

  13. Power Management and Distribution Trades Studies for a Deep-Space Mission Scientific Spacecraft

    NASA Technical Reports Server (NTRS)

    Kimnach, Greg L.; Soltis, James V.

    2004-01-01

    As part of NASA's Project Prometheus, the Nuclear Systems Program, NASA GRC performed trade studies on the various Power Management and Distribution (PMAD) options for a deep-space scientific spacecraft which would have a nominal electrical power requirement of 100 kWe. These options included AC (1000Hz and 1500Hz and DC primary distribution at various voltages. The distribution system efficiency, reliability, mass, thermal, corona, space radiation levels and technology readiness of devices and components were considered. The final proposed system consisted of two independent power distribution channels, sourced by two 3-phase, 110 kVA alternators nominally operating at half-rated power. Each alternator nominally supplies 50kWe to one half of the ion thrusters and science modules but is capable of supplying the total power re3quirements in the event of loss of one alternator. This paper is an introduction to the methodology for the trades done to arrive at the proposed PMAD architecture. Any opinions expressed are those of the author(s) and do not necessarily reflect the views of Project Prometheus.

  14. Current dependence of heat leak on the terminals in the superconducting DC transmission and distribution system of CASER-2

    NASA Astrophysics Data System (ADS)

    Kawahara, Toshio; Watanabe, Hirofumi; Emoto, Masahiko; Hamabe, Makoto; Yamaguchi, Sataro; Hikichi, Yasuo; Minowa, Masahiro

    2012-12-01

    Superconductivity can solve the energy problems in the world as energy saving technologies. In particular, superconducting direct current (DC) transmission and distribution (T&D) systems is promising, as it can be easily extended to large scale energy transmission systems for energy sharing. We are developing criogenic systems for effective cooling of superconducting T&D systems. In the cooling experiments with the 200 m-class superconducting DC T&D system at Chubu University (CASER-2), we have estimated the performance of the system. For example, our superconducting cable is connected to the outside at the terminals using Peltier current leads (PCLs). The PCL is composed of a thermoelectric material and a copper lead. Small thermal conductivity and large thermopower of the thermoelectric modules can effectively insulate the heat leak to the low temperature end. We measured the temperature along the current leads and the heat leak at the terminals. As current leads have an optimal shape factor, the optimum operation current exists. The current dependence of the system performance is discussed.

  15. Novel bidirectional DC-DC converters based on the three-state switching cell

    NASA Astrophysics Data System (ADS)

    da Silva Júnior, José Carlos; Robles Balestero, Juan Paulo; Lessa Tofoli, Fernando

    2016-05-01

    It is well known that there is an increasing demand for bidirectional DC-DC converters for applications that range from renewable energy sources to electric vehicles. Within this context, this work proposes novel DC-DC converter topologies that use the three-state switching cell (3SSC), whose well-known advantages over conventional existing structures are ability to operate at high current levels, while current sharing is maintained by a high frequency transformer; reduction of cost and dimensions of magnetics; improved distribution of losses, with consequent increase of global efficiency and reduction of cost associated to the need of semiconductors with lower current ratings. Three distinct topologies can be derived from the 3SSC: one DC-DC converter with reversible current characteristic able to operate in the first and second quadrants; one DC-DC converter with reversible voltage characteristic able to operate in the first and third quadrants and one DC-DC converter with reversible current and voltage characteristics able to operate in four quadrants. Only the topology with bidirectional current characteristic is analysed in detail in terms of the operating stages in both nonoverlapping and overlapping modes, while the design procedure of the power stage elements is obtained. In order to validate the theoretical assumptions, an experimental prototype is also implemented, so that relevant issues can be properly discussed.

  16. Distribution of Total Gas Phase Mercury During the NASA DC-8 INTEX-B Campaign

    NASA Astrophysics Data System (ADS)

    Talbot, R. W.; Mao, H.; Scheuer, E.; Dibb, J.; Blake, D. R.; Sachse, G.

    2006-12-01

    Measurements of total gaseous mercury (TGM = elemental plus reactive) were conducted aboard the NASA DC-8 research aircraft during the INTEX-B field campaign. We used a pressure controlled Tekran model 2537A equipped with a permeation device for conducting in-flight standard addition calibrations. Data was obtained with 2.5 minute time resolution spanning the altitude range of 0.15 - 12.5 km. Flights performed during March 2006 studied Mexico City pollution outflow, while the second phase during April - May focused on Asian pollution outflow over the central and eastern North Pacific. The mixing ratio of TGM in aged marine air averaged 90 parts per quadrillion by volume (ppqv), with values approaching 500 ppqv observed downwind of Mexico City. Over the Pacific to the north and northwest of Hawaii, TGM mixing ratios approached 200 ppqv in aged Asian continental outflow at altitudes from 0.5 to 2 km. Within these plumes we examined correlations with the combustion tracers CO and C2H2, as well as halogenated urban tracers. On several occasions stratospheric air was encountered, with corresponding TGM mixing ratios essentially zero.

  17. Dependence of DC HTS Cable Critical Current on the Temperature Distribution along the Cable

    NASA Astrophysics Data System (ADS)

    Vyatkin, Vladimir S.; Sun, Jian; Ivanov, Yury V.; Chikumoto, Noriko; Watanabe, Hirofumi; Shyshkin, Oleg; Yamaguchi, Satarou

    A temperature of the long HTS cable increases with the temperature of the liquid nitrogen flowing along the cable accumulating the heat load. Therefore, the critical current decreases along the cable and in the part of the cable near outlet becomes the minimum. The critical current of the long HTS cable is estimated by the voltage drop across the cable. The typical n-value of the voltage-current characteristic of the cable is about 10-20. The decreasing of the critical current near the outlet leads the increasing of local electrical losses and it causes consequently the increasing of the local temperature of liquid nitrogen. In spite of the fact, that average electrical field is enough low (E0 = 10-6V/cm) the local current can be higher than the critical one. Measurement of the critical current with criterion of average electrical field cannot provide the safe heat losses value in every part of the cable. In the present paper the local heat generation along the cable and the method for providing the safe local DC heat losses in the every part of the cable are discussed.

  18. Space Power Management and Distribution Status and Trends

    NASA Technical Reports Server (NTRS)

    Reppucci, G. M.; Biess, J. J.; Inouye, L.

    1984-01-01

    An overview of space power management and distribution (PMAD) is provided which encompasses historical and current technology trends. The PMAD components discussed include power source control, energy storage control, and load power processing electronic equipment. The status of distribution equipment comprised of rotary joints and power switchgear is evaluated based on power level trends in the public, military, and commercial sectors. Component level technology thrusts, as driven by perceived system level trends, are compared to technology status of piece-parts such as power semiconductors, capacitors, and magnetics to determine critical barriers.

  19. Power Distribution of Hybrid Electric Vehicles

    NASA Astrophysics Data System (ADS)

    Kato, Kenta; Morimoto, Masayuki

    In this paper, the fuel consumption of the hybrid electric vehicles is analyzed by the rated power of the engine and the motor. The analysis was based on the published data only. Hybrid ratio and normalized fuel consumption are defined. As the result, the key for the high mileage of hybrid electric vehicle is to use the high power motor and the low power engine.

  20. Distribution of trace metals in the vicinity of a wastewater treatment plant on the Potomac River, Washington, DC, USA

    NASA Astrophysics Data System (ADS)

    Smith, J. P.; Muller, A. C.

    2013-05-01

    Predicting the fate and distribution of anthropogenic-sourced trace metals in riverine and estuarine systems is challenging due to multiple and varying source functions and dynamic physiochemical conditions. Between July 2011 and November 2012, sediment and water column samples were collected from over 20 sites in the tidal-fresh Potomac River estuary, Washington, DC near the outfall of the Blue Plains Advanced Wastewater Treatment Plant (BPWTP) for measurement of select trace metals. Field observations of water column parameters (conductivity, temperature, pH, turbidity) were also made at each sampling site. Trace metal concentrations were normalized to the "background" composition of the river determined from control sites in order to investigate the distribution BPWTP-sourced in local Potomac River receiving waters. Temporal differences in the observed distribution of trace metals were attributed to changes in the relative contribution of metals from different sources (wastewater, riverine, other) coupled with differences in the physiochemical conditions of the water column. Results show that normalizing near-source concentrations to the background composition of the water body and also to key environmental parameters can aid in predicting the fate and distribution of anthropogenic-sourced trace metals in dynamic riverine and estuarine systems like the tidal-fresh Potomac River.

  1. Control method for peak power delivery with limited DC-bus voltage

    DOEpatents

    Edwards, John; Xu, Longya; Bhargava, Brij B.

    2006-09-05

    A method for driving a neutral point-clamped multi-level voltage source inverter supplying a synchronous motor is provided. A DC current is received at a neutral point-clamped multi-level voltage source inverter. The inverter has first, second, and third output nodes. The inverter also has a plurality of switches. A desired speed of a synchronous motor connected to the inverter by the first second and third nodes is received by the inverter. The synchronous motor has a rotor and the speed of the motor is defined by the rotational rate of the rotor. A position of the rotor is sensed, current flowing to the motor out of at least two of the first, second, and third output nodes is sensed, and predetermined switches are automatically activated by the inverter responsive to the sensed rotor position, the sensed current, and the desired speed.

  2. A Testbed for Deploying Distributed State Estimation in Power Grid

    SciTech Connect

    Jin, Shuangshuang; Chen, Yousu; Rice, Mark J.; Liu, Yan; Gorton, Ian

    2012-07-22

    Abstract—With the increasing demand, scale and data information of power systems, fast distributed applications are becoming more important in power system operation and control. This paper proposes a testbed for evaluating power system distributed applications, considering data exchange among distributed areas. A high-performance computing (HPC) version of distributed state estimation is implemented and used as a distributed application example. The IEEE 118-bus system is used to deploy the parallel distributed state estimation, and the MeDICi middleware is used for data communication. The performance of the testbed demonstrates its capability to evaluate parallel distributed state estimation by leveraging the HPC paradigm. This testbed can also be applied to evaluate other distributed applications.

  3. Profiles of lipid components, fatty acid distributions of triacylglycerols and phospholipids in Jack beans (Canavalia gladiata DC.).

    PubMed

    Yoshida, Hiromi; Yoshida, Naoko; Kuriyama, Isoko; Tomiyama-Sakamoto, Yuka; Mizushina, Yoshiyuki

    2013-01-15

    Endogenous tocopherols in extracted lipids from Jack beans (Canavalia gladiata DC.) were determined by high-performance liquid chromatography (HPLC), and were investigated in relation to the fatty acids (FA) distribution of triacylgycerols (TAG) and phospholipids (PL). The dominant tocopherols were (δ)-tocopherol (78.9-96.5mg%) and (γ)-tocopherol (42.1-56.1mg%) with much smaller amounts of (α)-tocopherol (1.1-1.3mg%). The lipids of Jack beans comprised mainly TAG (34.6-38.6 wt.%) and PL (54.8-57.4 wt.%), and other components were also detected in minor proportions (0.3-3.8 wt.%). The PL components included phosphatidyl choline (46.2-48.7 wt.%), phosphatidyl inositol (23.4-29.6 wt.%) and phosphatidyl ethanolamine (18.5-21.2 wt.%). Comparison of these different beans showed, with a few exceptions, no significant differences (P>0.05) in FA distribution. The FA distribution of TAG among the five beans was evident in the Jack beans: unsaturated FA (93.3-95.3 wt.%) were predominantly concentrated at the sn-2 position and saturated FA (33.6-34.4 wt.%) primarily occupying the sn-1 position or sn-3 position. The results obtained from this work would provide useful information to both producers and consumers for manufacturing functional foods or beverages in Japan and elsewhere.

  4. Inverter power module with distributed support for direct substrate cooling

    DOEpatents

    Miller, David Harold; Korich, Mark D.; Ward, Terence G.; Mann, Brooks S.

    2012-08-21

    Systems and/or methods are provided for an inverter power module with distributed support for direct substrate cooling. An inverter module comprises a power electronic substrate. A first support frame is adapted to house the power electronic substrate and has a first region adapted to allow direct cooling of the power electronic substrate. A gasket is interposed between the power electronic substrate and the first support frame. The gasket is configured to provide a seal between the first region and the power electronic substrate. A second support frame is adapted to house the power electronic substrate and joined to the first support frame to form the seal.

  5. Electric Transport Traction Power Supply System With Distributed Energy Sources

    NASA Astrophysics Data System (ADS)

    Abramov, E. Y.; Schurov, N. I.; Rozhkova, M. V.

    2016-04-01

    The paper states the problem of traction substation (TSS) leveling of daily-load curve for urban electric transport. The circuit of traction power supply system (TPSS) with distributed autonomous energy source (AES) based on photovoltaic (PV) and energy storage (ES) units is submitted here. The distribution algorithm of power flow for the daily traction load curve leveling is also introduced in this paper. In addition, it illustrates the implemented experiment model of power supply system.

  6. Automation of Space Station module power management and distribution system

    NASA Technical Reports Server (NTRS)

    Bechtel, Robert; Weeks, Dave; Walls, Bryan

    1990-01-01

    Viewgraphs on automation of space station module (SSM) power management and distribution (PMAD) system are presented. Topics covered include: reasons for power system automation; SSM/PMAD approach to automation; SSM/PMAD test bed; SSM/PMAD topology; functional partitioning; SSM/PMAD control; rack level autonomy; FRAMES AI system; and future technology needs for power system automation.

  7. Automated distribution system management for multichannel space power systems

    NASA Technical Reports Server (NTRS)

    Fleck, G. W.; Decker, D. K.; Graves, J.

    1983-01-01

    A NASA sponsored study of space power distribution system technology is in progress to develop an autonomously managed power system (AMPS) for large space power platforms. The multichannel, multikilowatt, utility-type power subsystem proposed presents new survivability requirements and increased subsystem complexity. The computer controls under development for the power management system must optimize the power subsystem performance and minimize the life cycle cost of the platform. A distribution system management philosophy has been formulated which incorporates these constraints. Its implementation using a TI9900 microprocessor and FORTH as the programming language is presented. The approach offers a novel solution to the perplexing problem of determining the optimal combination of loads which should be connected to each power channel for a versatile electrical distribution concept.

  8. Local control of reactive power by distributed photovoltaic generators

    SciTech Connect

    Chertkov, Michael; Turitsyn, Konstantin; Sulc, Petr; Backhaus, Scott

    2010-01-01

    High penetration levels of distributed photovoltaic (PV) generation on an electrical distribution circuit may severely degrade power quality due to voltage sags and swells caused by rapidly varying PV generation during cloud transients coupled with the slow response of existing utility compensation and regulation equipment. Although not permitted under current standards for interconnection of distributed generation, fast-reacting, VAR-capable PV inverters may provide the necessary reactive power injection or consumption to maintain voltage regulation under difficult transient conditions. As side benefit, the control of reactive power injection at each PV inverter provides an opportunity and a new tool for distribution utilities to optimize the performance of distribution circuits, e.g. by minimizing thermal losses. We suggest a local control scheme that dispatches reactive power from each PV inverter based on local instantaneous measurements of the real and reactive components of the consumed power and the real power generated by the PVs. Using one adjustable parameter per circuit, we balance the requirements on power quality and desire to minimize thermal losses. Numerical analysis of two exemplary systems, with comparable total PV generation albeit a different spatial distribution, show how to adjust the optimization parameter depending on the goal. Overall, this local scheme shows excellent performance; it's capable of guaranteeing acceptable power quality and achieving significant saving in thermal losses in various situations even when the renewable generation in excess of the circuit own load, i.e. feeding power back to the higher-level system.

  9. High-voltage (270 V) dc power-generating system for fighter aircraft

    NASA Technical Reports Server (NTRS)

    Mcginley, K. M.

    1983-01-01

    The advantages of using high voltage, direct current advanced power generating systems in fighter aircraft are discussed. Weight reduction is achieved. Efficiency is increased 85 to 90 percent by eliminating the constant speed drive. Power interruptions are eliminated. There are no speed restrictions and no powerline constraints. Personal safety is increased by eliminating the hold on frequency, present in ac systems, which causes muscle contractions.

  10. High-voltage (270 V) dc power-generating system for fighter aircraft

    NASA Astrophysics Data System (ADS)

    McGinley, K. M.

    1983-06-01

    The advantages of using high voltage, direct current advanced power generating systems in fighter aircraft are discussed. Weight reduction is achieved. Efficiency is increased 85 to 90 percent by eliminating the constant speed drive. Power interruptions are eliminated. There are no speed restrictions and no powerline constraints. Personal safety is increased by eliminating the hold on frequency, present in ac systems, which causes muscle contractions.

  11. DC CIRCUIT POWERED BY ORBITAL MOTION: MAGNETIC INTERACTIONS IN COMPACT OBJECT BINARIES AND EXOPLANETARY SYSTEMS

    SciTech Connect

    Lai Dong

    2012-09-20

    The unipolar induction DC circuit model, originally developed by Goldreich and Lynden-Bell for the Jupiter-Io system, has been applied to different types of binary systems in recent years. We show that there exists an upper limit to the magnetic interaction torque and energy dissipation rate in such a model. This arises because when the resistance of the circuit is too small, the large current flow severely twists the magnetic flux tube connecting the two binary components, leading to the breakdown of the circuit. Applying this limit, we find that in coalescing neutron star binaries, magnetic interactions produce negligible correction to the phase evolution of the gravitational waveform, even for magnetar-like field strengths. However, energy dissipation in the binary magnetosphere may still give rise to electromagnetic radiation prior to the final merger. For ultracompact white dwarf binaries, we find that unipolar induction does not provide adequate energy dissipation to explain the observed X-ray luminosities of several sources. For exoplanetary systems containing close-in Jupiters or super-Earths, the magnetic torque and energy dissipation induced by the orbital motion are negligible, except possibly during the early T Tauri phase, when the stellar magnetic field is stronger than 10{sup 3} G.

  12. Operation of high power converters in parallel

    NASA Technical Reports Server (NTRS)

    Decker, D. K.; Inouye, L. Y.

    1992-01-01

    Three different unequal power sharing approaches for parallel operation of converters - droop, master-slave, and proportional adjustment - are discussed. The approaches have been incorporated in the breadboard dc-dc converter units used in the space station power management and distribution dc test bed at the Lewis Research Center, where the system operation has been verified.

  13. Space-based solar power generation using a distributed network of satellites and methods for efficient space power transmission

    NASA Astrophysics Data System (ADS)

    McLinko, Ryan M.; Sagar, Basant V.

    2009-12-01

    . The only satellites that are constrained to a significant mass are the beam-down satellites, which still require significant transmission arrays to sufficiently focus the beams targeting corresponding ground stations. With robust design and inherent redundancy built-in, power generation and transmission will not be interrupted in the event of mishaps like space debris collision. Furthermore, the "plug and play" nature of this system significantly reduces the cost, complexity, and risk of upgrading the system. The distributed nature of smallsat clusters maximizes the use of economies of scale. This approach retains some problems of older designs and introduces additional ones. Mitigations will be explored further. For example, the distributed nature of the system requires very precise coordination between and among satellites and a mature attitude control and determination system. Such a design incorporates multiple beaming stages, which has the potential to reduce overall system efficiency. Although this design eliminates the need for space assembly, it retains the challenge of significant on-orbit deployment of solar and transmission arrays. Space power "beaming" is a three step process that involves: 1) conversion of dc power generated by solar cells on the satellite into an electromagnetic wave of suitable frequency, 2) transmission of that wave to power stations on ground, and 3) conversion of the radio waves back into dc power. A great deal of research has been done on the use of microwaves for this purpose. Various factors that affect efficient power generation and transmission will be analyzed in this paper. Based on relevant theory and performance and optimization models, the paper proposes solutions that will help make space-based solar power generation a practical and viable option for addressing the world's growing energy needs.

  14. Solid state d.c. power controller design philosophies and their evaluation.

    NASA Technical Reports Server (NTRS)

    Maus, L. G.; Williams, D. E.

    1972-01-01

    Evaluation of remote power controllers (RPC), which has enhanced knowledge of the capabilities of various design philosophies and has indicated certain limitations that RPC's exhibit. Additionally, this activity has clearly emphasized that certain RPC design parameters merit further consideration in development. The major design parameters to be analyzed in more detail are the rates of change of the rise and fall times of the output current. The major reason why transient voltages and currents should be reduced is the minimization of the reverse collector-to-emitter voltage. The requirement for higher bus voltage coupled with the present problem of improving the efficiency of power control points out the urgent need for improvement and advancement of higher current, voltage, and gain power semiconductors.

  15. Low power dc arcjet operation with hydrogen/nitrogen propellant mixtures

    NASA Technical Reports Server (NTRS)

    Curran, F. M.; Nakanishi, S.

    1986-01-01

    The arcjet assembly from a flight model system was modified with a new thoriated tungsten nozzle insert and has been tested with hydrogen-nitrogen mixtures simulating the decomposition products of ammonia and hygrazine. Arcjet power consumption ranged from 0.7 to 1.15 kW depending on low rate, input current, and mixture composition. At a nominal 1 kW power level the ammonia mixtures thrust efficiency was about 0.31 at specific impulse values ranging between 460 and 500 sec. Hydrazine mixtures gave similar thrust efficiencies at the same power level with specific impulse values between 395 and 430 sec. Large, spontaneous voltage mode changes were not observed once the thruster had passed a period of instability immediately following start up. This period of instability, and the startup at low pressure, were seen as major causes of constrictor damage during the tests.

  16. Lower power dc arcjet operations with hydrogen hydrogen/nitrogen propellant mixtures

    NASA Technical Reports Server (NTRS)

    Curran, F. M.; Nakanishi, S.

    1986-01-01

    The arcjet assembly from a flight model system was modified with a new thoriated tungsten nozzle insert and has been tested with hydrogen-nitrogen mixtures simulating the decomposition products of ammonia and hydrazine. Arcjet power consumption ranged from 0.7 to 1.15 kW depending on low rate, input current, and mixture composition. At a nominal 1 kW power level the ammonia mixtures thrust efficiency was about 0.31 at specific impulse values ranging between 460 and 500 sec. Hydrazine mixtures gave similar thrust efficiencies at the same power level with specific impulse values between 395 and 430 sec. Large, spontaneous voltage mode changes were not observed once the thruster had passed a period of instability immediately following start up. This period of instability, and the startup at low pressure, were seen as major causes of constrictor damage during the tests.

  17. Thresholded Power law Size Distributions of Instabilities in Astrophysics

    NASA Astrophysics Data System (ADS)

    Aschwanden, Markus J.

    2015-11-01

    Power-law-like size distributions are ubiquitous in astrophysical instabilities. There are at least four natural effects that cause deviations from ideal power law size distributions, which we model here in a generalized way: (1) a physical threshold of an instability; (2) incomplete sampling of the smallest events below a threshold x0; (3) contamination by an event-unrelated background xb; and (4) truncation effects at the largest events due to a finite system size. These effects can be modeled in the simplest terms with a “thresholded power law” distribution function (also called generalized Pareto [type II] or Lomax distribution), N(x){dx}\\propto {(x+{x}0)}-a{dx}, where x0 > 0 is positive for a threshold effect, while x0 < 0 is negative for background contamination. We analytically derive the functional shape of this thresholded power law distribution function from an exponential growth evolution model, which produces avalanches only when a disturbance exceeds a critical threshold x0. We apply the thresholded power law distribution function to terrestrial, solar (HXRBS, BATSE, RHESSI), and stellar flare (Kepler) data sets. We find that the thresholded power law model provides an adequate fit to most of the observed data. Major advantages of this model are the automated choice of the power law fitting range, diagnostics of background contamination, physical instability thresholds, instrumental detection thresholds, and finite system size limits. When testing self-organized criticality models that predict ideal power laws, we suggest including these natural truncation effects.

  18. Circuit for Communication over DC Power Line Using High Temperature Electronics

    NASA Technical Reports Server (NTRS)

    Krasowski, Michael J. (Inventor); Prokop, Norman F. (Inventor)

    2014-01-01

    A high temperature communications circuit includes a power conductor for concurrently conducting electrical energy for powering circuit components and transmitting a modulated data signal, and a demodulator for demodulating the data signal and generating a serial bit stream based on the data signal. The demodulator includes an absolute value amplifier for conditionally inverting or conditionally passing a signal applied to the absolute value amplifier. The absolute value amplifier utilizes no diodes to control the conditional inversion or passing of the signal applied to the absolute value amplifier.

  19. Entomofauna resource distribution associated with pig cadavers in Bogotá DC.

    PubMed

    Segura, N A; Bonilla, M A; Usaquén, W; Bello, F

    2011-03-01

    A cadaver represents a temporal energy-loaded resource, which provides arthropods with food, protection and a place in which to find a mate. Insects are usually the first organisms to discover and colonize a cadaver; as decomposition progresses, insects colonize cadavers in a predictable sequence. This work aimed to establish cadaverous entomofauna relationships with regard to stages of decomposition and environmental conditions using multiple correspondence analysis and thereby to identify the way in which insects distribute a perishable and changing resource. Entomofauna were thus collected in a semi-rural area near Bogotá from the cadavers of three pigs (Sus scrofa L.) which had been shot. Environmental variables were recorded for each sampling. Multiple correspondence analyses were carried out for adult forms belonging to Diptera and Coleoptera families and stages of decomposition, and for Diptera and Coleoptera adult forms and environmental conditions. Stages of decomposition were a primary determining factor for structuring four guilds of entomofauna. However, environmental conditions influenced insect activity and were therefore a relevant factor in the structure of the entomofauna community. The results showed that the insects' distribution of available resources was related to changes in the stage of decomposition. PMID:21143612

  20. Entomofauna resource distribution associated with pig cadavers in Bogotá DC.

    PubMed

    Segura, N A; Bonilla, M A; Usaquén, W; Bello, F

    2011-03-01

    A cadaver represents a temporal energy-loaded resource, which provides arthropods with food, protection and a place in which to find a mate. Insects are usually the first organisms to discover and colonize a cadaver; as decomposition progresses, insects colonize cadavers in a predictable sequence. This work aimed to establish cadaverous entomofauna relationships with regard to stages of decomposition and environmental conditions using multiple correspondence analysis and thereby to identify the way in which insects distribute a perishable and changing resource. Entomofauna were thus collected in a semi-rural area near Bogotá from the cadavers of three pigs (Sus scrofa L.) which had been shot. Environmental variables were recorded for each sampling. Multiple correspondence analyses were carried out for adult forms belonging to Diptera and Coleoptera families and stages of decomposition, and for Diptera and Coleoptera adult forms and environmental conditions. Stages of decomposition were a primary determining factor for structuring four guilds of entomofauna. However, environmental conditions influenced insect activity and were therefore a relevant factor in the structure of the entomofauna community. The results showed that the insects' distribution of available resources was related to changes in the stage of decomposition.

  1. Organic Halogen and Hydrocarbon Distributions During SEAC4RS Measured from the ER-2 and DC-8.

    NASA Astrophysics Data System (ADS)

    Schauffler, S.; Atlas, E. L.; Navarro, M. A.; Pan, L.; Blake, D. R.; Blake, N. J.; Kinnison, D. E.; Meinardi, S.; Lueb, R.; Zhu, X.; Pope, L.

    2014-12-01

    Organic halogens and hydrocarbons are important contributors to chemical processes in the upper troposphere/lower stratosphere (UTLS) region and hydrocarbons are well known contributors to chemical processes throughout the troposphere. Whole Air Sampler systems (WAS) were deployed during Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS) on the NASA ER-2 (Univ. of Miami WAS) and the NASA DC-8 (Univ. of California, Irvine WAS). Both systems measured a wide variety of organic halogen and hydrocarbon species in the samples collected. For this presentation we show the vertical distributions of select chemical species from the surface to the lower stratosphere and compare those distributions to the Community Atmosphere Model with Chemistry (CAM-Chem) in order to evaluate their representation in the global model. We also show a comparison of measurements taken during SEAC4RS (2013) with those taken in the same region during the Stratosphere-Troposphere Analysis of Regional Transport 2008 (START08) campaign. The Univ. of Miami WAS system was flown on the NSF/NCAR GV during START08. The two campaigns were conducted in different seasons and different stratosphere/troposphere exchange regimes, allowing evaluation of how the North American Monsoon convection influences the transport time scale in the UTLS (during SEAC4RS) relative to the pre-monsoon regime observed during START08.

  2. Statistical analyses support power law distributions found in neuronal avalanches.

    PubMed

    Klaus, Andreas; Yu, Shan; Plenz, Dietmar

    2011-01-01

    The size distribution of neuronal avalanches in cortical networks has been reported to follow a power law distribution with exponent close to -1.5, which is a reflection of long-range spatial correlations in spontaneous neuronal activity. However, identifying power law scaling in empirical data can be difficult and sometimes controversial. In the present study, we tested the power law hypothesis for neuronal avalanches by using more stringent statistical analyses. In particular, we performed the following steps: (i) analysis of finite-size scaling to identify scale-free dynamics in neuronal avalanches, (ii) model parameter estimation to determine the specific exponent of the power law, and (iii) comparison of the power law to alternative model distributions. Consistent with critical state dynamics, avalanche size distributions exhibited robust scaling behavior in which the maximum avalanche size was limited only by the spatial extent of sampling ("finite size" effect). This scale-free dynamics suggests the power law as a model for the distribution of avalanche sizes. Using both the Kolmogorov-Smirnov statistic and a maximum likelihood approach, we found the slope to be close to -1.5, which is in line with previous reports. Finally, the power law model for neuronal avalanches was compared to the exponential and to various heavy-tail distributions based on the Kolmogorov-Smirnov distance and by using a log-likelihood ratio test. Both the power law distribution without and with exponential cut-off provided significantly better fits to the cluster size distributions in neuronal avalanches than the exponential, the lognormal and the gamma distribution. In summary, our findings strongly support the power law scaling in neuronal avalanches, providing further evidence for critical state dynamics in superficial layers of cortex.

  3. A dc model for power switching transistors suitable for computer-aided design and analysis

    NASA Technical Reports Server (NTRS)

    Wilson, P. M.; George, R. T., Jr.; Owen, H. A.; Wilson, T. G.

    1979-01-01

    A model for bipolar junction power switching transistors whose parameters can be readily obtained by the circuit design engineer, and which can be conveniently incorporated into standard computer-based circuit analysis programs is presented. This formulation results from measurements which may be made with standard laboratory equipment. Measurement procedures, as well as a comparison between actual and computed results, are presented.

  4. Voltage Control in Distribution Systems Considered Reactive Power Output Sharing

    NASA Astrophysics Data System (ADS)

    Oshiro, Masato; Senjyu, Tomonobu; Yona, Atsushi; Urasaki, Naomitsu; Funabashi, Toshihisa

    In recent years, distributed generation (DG) and renewable energy source (RES) are attracting special attention to distribution systems. Renewable energy such as photovoltaic (PV) system and wind turbine generator are used as a source of clean energy. However, the large amount of distributed generation causes voltage deviation beyond a statutory range in distribution systems. This paper proposes a methodology for voltage control by using inverters interfaced with DG and tap changing transformers. In the proposed method a one-day schedule of voltage references for the control devices are determined by an optimization technique based on predicted values of load demand and PV power generation. Furthermore, decided reactive power output according to the locally measurable voltage based on droop characteristic. Slope and base value on droop characteristic are selected by fuzzy control. The proposed method accomplishes improvement against voltage distribution considered the reactive power output sharing and reduction of distribution loss. The effectiveness of the proposed method is verified by using MATLAB®.

  5. Distribution of Electric Field across Shock Structure Propagating through a DC Glow Discharge

    NASA Astrophysics Data System (ADS)

    Popovic, S.; Vuskovic, L.

    1998-10-01

    A number of experiments confirmed the existence of double electric layer (DEL) due to ambipolar diffusion of electrons and ions in the shock front propagating through partially ionized gas. It was used to visualize shock shapes with an electric discharge transverse to the flow. Charge separation generated local electric field that interacted with the electric field of the discharge, to slow down the electron drift, and resulted in a decrease of luminosity along shock front. DEL effect was used to demonstrate a "bow shock generator." Voltage difference between upstream and downstream region of partially ionized gas depended on shock strength manifested in electron temperature and number density gradients. These two gradients did not necessarily coincide, and more than one DEL could be associated with the shock. Based on these facts, we derived reduced electric field distributions in a planar and oblique shock structure. We also determined the parameters and stability criteria for the regions of enhanced degree of ionization associated with DEL.

  6. Photovoltaic Power System and Power Distribution Demonstration for the Desert RATS Program

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony; Jakupca, Ian; Mintz, Toby; Herlacher, Mike; Hussey, Sam

    2012-01-01

    A stand alone, mobile photovoltaic power system along with a cable deployment system was designed and constructed to take part in the Desert Research And Technology Studies (RATS) lunar surface human interaction evaluation program at Cinder Lake, Arizona. The power system consisted of a photovoltaic array/battery system. It is capable of providing 1 kW of electrical power. The system outputs were 48 V DC, 110 V AC, and 220 V AC. A cable reel with 200 m of power cable was used to provide power from the trailer to a remote location. The cable reel was installed on a small trailer. The reel was powered to provide low to no tension deployment of the cable. The cable was connected to the 220 V AC output of the power system trailer. The power was then converted back to 110 V AC on the cable deployment trailer for use at the remote site. The Scout lunar rover demonstration vehicle was used to tow the cable trailer and deploy the power cable. This deployment was performed under a number of operational scenarios, manned operation, remote operation and tele-robotically. Once deployed, the cable was used to provide power, from the power system trailer, to run various operational tasks at the remote location.

  7. The impact of hybrid energy storage on power quality, when high power pulsed DC loads are operated on a microgrid testbed

    NASA Astrophysics Data System (ADS)

    Kelley, Jay Paul

    . This enables the generator to maintain its operation at levels of high efficiency thereby increasing the power quality of the AC bus. The work discussed here is aimed at evaluating how the use of energy storage impacts the power quality on MicroGrid's AC bus when high rate DC and AC loads are sourced simultaneously. Also HESM has been developed and evaluated as a mean to optimizing both the power and energy density of the energy storage installed.

  8. A study of power conditioning and power distribution and components

    NASA Technical Reports Server (NTRS)

    Horton, H. M.; Honnell, M. A.

    1973-01-01

    A comprehensive simulation and analysis performed on the operation of the regulator part of the Charger/Battery/Regulator Module (CBRM) are detailed. The CBRM is utilized as an integral component of the Skylab/Apollo Telescope Mount (ATM) electrical power system and contains a switching mode electronic regulator. Implementing circuit analysis techniques, pertinent voltages and currents are calculated; these, in turn, are incorporated into the regulator system study. Investigation of the turn-on and turn-off times associated with the switching circuitry is performed and an examination is made on these calculations. A simulation model computer program is utilized to generate graphs that relate various CBRM parameters to one another.

  9. Thirty-Third Annual Power Distribution Conference

    SciTech Connect

    Oerting, J.A. Jr.

    1980-01-01

    A description is given of how the Gulf Power Company which serves 10 westernmost counties of Florida deals with hurricanes. Gulf's hurricane procedures currently contain 661 pages of detailed information for each area of responsibility, including the general concept for restoration of damage, as well as details describing how this will be accomplished. Included are area storm center locations, personnel assignments, material allocations, vehicle assignments, radio frequencies, news media contacts, special priorities for restoration of service, details of logistics associated with lodging and feeding, telephone center operation to take incoming calls from customers and all of the other functions.

  10. Space Station Freedom power management and distribution system design

    NASA Technical Reports Server (NTRS)

    Teren, Fred

    1989-01-01

    The design is described of the Space Station Freedom Power Management and Distribution (PMAD) System. In addition, the significant trade studies which were conducted are described, which led to the current PMAD system configuration.

  11. Short circuit protection for a power distribution system

    NASA Technical Reports Server (NTRS)

    Owen, J. R., III

    1969-01-01

    Sensing circuit detects when the output from a matrix is present and when it should be present. The circuit provides short circuit protection for a power distribution system where the selection of the driven load is accomplished by digital logic.

  12. Power distribution in two-dimensional optical network channels

    NASA Astrophysics Data System (ADS)

    Wang, Dong-Xue; Karim, Mohammad A.

    1996-04-01

    The power distribution in two-dimensional optical network channels is analyzed. The maximum number of allowable channels as determined by the characteristics of optical detector is identified, in particular, for neural-network and wavelet-transform applications.

  13. Shuttle Electrical Power Analysis Program (SEPAP) distribution circuit analysis report

    NASA Technical Reports Server (NTRS)

    Torina, E. M.

    1975-01-01

    An analysis and evaluation was made of the operating parameters of the shuttle electrical power distribution circuit under load conditions encountered during a normal Sortie 2 Mission with emphasis on main periods of liftoff and landing.

  14. Early Oscillation Detection for DC/DC Converter Fault Diagnosis

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2011-01-01

    The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

  15. Energy loss analysis of an integrated space power distribution system

    NASA Technical Reports Server (NTRS)

    Kankam, M. D.; Ribeiro, P. F.

    1992-01-01

    The results of studies related to conceptual topologies of an integrated utility-like space power system are described. The system topologies are comparatively analyzed by considering their transmission energy losses as functions of mainly distribution voltage level and load composition. The analysis is expedited by use of a Distribution System Analysis and Simulation (DSAS) software. This recently developed computer program by the Electric Power Research Institute (EPRI) uses improved load models to solve the power flow within the system. However, present shortcomings of the software with regard to space applications, and incompletely defined characteristics of a space power system make the results applicable to only the fundamental trends of energy losses of the topologies studied. Accountability, such as included, for the effects of the various parameters on the system performance can constitute part of a planning tool for a space power distribution system.

  16. A new on-chip all-digital three-phase full-bridge dc/ac power inverter with feedforward and frequency control techniques.

    PubMed

    Chen, Jiann-Jong; Kung, Che-Min

    2010-09-01

    The communication speed between components is far from satisfactory. To achieve high speed, simple control system configuration, and low cost, a new on-chip all-digital three-phase dc/ac power inverter using feedforward and frequency control techniques is proposed. The controller of the proposed power inverter, called the shift register, consists of six-stage D-latch flip-flops with a goal of achieving low-power consumption and area efficiency. Variable frequency is achieved by controlling the clocks of the shift register. One advantage regarding the data signal (D) and the common clock (CK) is that, regardless of the phase difference between the two, all of the D-latch flip-flops are capable of delaying data by one CK period. To ensure stability, the frequency of CK must be six times higher than that of D. The operation frequency of the proposed power inverter ranges from 10 Hz to 2 MHz, and the maximum output loading current is 0.8 A. The prototype of the proposed circuit has been fabricated with TSMC 0.35 μm 2P4M CMOS processes. The total chip area is 2.333 x 1.698 mm2. The three-phase dc/ac power inverter is applicable in uninterrupted power supplies, cold cathode fluorescent lamps, and motors, because of its ability to convert the dc supply voltage into the three-phase ac power sources.

  17. High power ac/dc variable R dynamic electrical load simulator

    NASA Technical Reports Server (NTRS)

    Joncas, K. P.

    1974-01-01

    A study program was undertaken to investigate various concepts and techniques for identifying and simulating both the steady-state and dynamic characteristics of electrical loads for use during integrated system test and evaluation. The development of hardware capable of providing the simulation capability is discussed. A general purpose simulator was developed with the capability of realizing a variety of models where element values were discretely variable. The different models, each corresponding to real spacecraft equipment, are set up manually for each case by suitable switching and patching. The models are capable of duplicating the dynamic and steady-state response of real loads at full power.

  18. A 2-Megawatt load for testing high voltage dc power supplies

    SciTech Connect

    Horan, D.; Kustom, R.; Ferguson, M.; Primdahl, K.

    1993-06-01

    A high power water-cooled resistive load, capable of dissipating 2 Megawatts at 95 kilovolts is being designed and built. The load utilizes wirewound resistor elements suspended inside insulating tubing contained within a pressure vessel which is supplied a continuous flow of deionized water for coolant. A sub-system of the load is composed of non-inductive resistor elements in an oil tank. Power tests conducted on various resistor types indicate that dissipation levels as high as 22 times the rated dissipation in air can be achieved when the resistors are placed in a turbulent water flow of at least 15 gallons per minute. Using this data, the load w.as designed using 100 resistor elements in a series arrangement A single-wall 316 stainless steel pressure vessel with flanged torispherical heads is built to contain the resistor assembly and deionized water. The resistors are suspended within G-11 tubing which span the cylindrical length of the vessel. These tubes are supported by G-10 baffles which also increase convection from the tubes by promoting turbulence within the surrounding water.

  19. Independent Orbiter Assessment (IOA): Analysis of the electrical power distribution and control subsystem, volume 1

    NASA Technical Reports Server (NTRS)

    Schmeckpeper, K. R.

    1987-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Electrical Power Distribution and Control (EPD and C) hardware. The EPD and C hardware performs the functions of distributing, sensing, and controlling 28 volt DC power and of inverting, distributing, sensing, and controlling 117 volt 400 Hz AC power to all Orbiter subsystems from the three fuel cells in the Electrical Power Generation (EPG) subsystem. Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode. Of the 1671 failure modes analyzed, 9 single failures were determined to result in loss of crew or vehicle. Three single failures unique to intact abort were determined to result in possible loss of the crew or vehicle. A possible loss of mission could result if any of 136 single failures occurred. Six of the criticality 1/1 failures are in two rotary and two pushbutton switches that control External Tank and Solid Rocket Booster separation. The other 6 criticality 1/1 failures are fuses, one each per Aft Power Control Assembly (APCA) 4, 5, and 6 and one each per Forward Power Control Assembly (FPCA) 1, 2, and 3, that supply power to certain Main Propulsion System (MPS) valves and Forward Reaction Control System (RCS) circuits.

  20. 62. View of amplifiermodulator control system with power distribution panel ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    62. View of amplifier-modulator control system with power distribution panel on left, control power supply in middle, and amplifier modulator on right, second floor in transmitter building no. 102. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  1. Distribution of Fe atom density in a dc magnetron sputtering plasma source measured by laser-induced fluorescence imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Shibagaki, K.; Nafarizal, N.; Sasaki, K.; Toyoda, H.; Iwata, S.; Kato, T.; Tsunashima, S.; Sugai, H.

    2003-10-01

    Magnetron sputtering discharge is widely used as an efficient method for thin film fabrication. In order to achieve the optimized fabrication, understanding of the kinetics in plasmas is essential. In the present work, we measured the density distribution of sputtered Fe atoms using laser-induced fluorescence imaging spectroscopy. A dc magnetron plasma source with a Fe target was used. An area of 20 × 2 mm in front of the target was irradiated by a tunable laser beam having a planar shape. The picture of laser-induced fluorescence on the laser beam was taken using an ICCD camera. In this way, we obtained the two-dimensional image of the Fe atom density. As a result, it has been found that the Fe atom density observed at a distance of several centimeters from the target is higher than that adjacent to the target, when the Ar gas pressure was relatively high. It is suggested from this result that some gas-phase production processes of Fe atoms are available in the plasma. This work has been performed under the 21st Century COE Program by the Ministry of Education, Culture, Sports, Science and Technology in Japan.

  2. Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices

    DOEpatents

    Chassin, David P.; Donnelly, Matthew K.; Dagle, Jeffery E.

    2011-12-06

    Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices are described. In one aspect, an electrical power distribution control method includes providing electrical energy from an electrical power distribution system, applying the electrical energy to a load, providing a plurality of different values for a threshold at a plurality of moments in time and corresponding to an electrical characteristic of the electrical energy, and adjusting an amount of the electrical energy applied to the load responsive to an electrical characteristic of the electrical energy triggering one of the values of the threshold at the respective moment in time.

  3. Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices

    DOEpatents

    Chassin, David P.; Donnelly, Matthew K.; Dagle, Jeffery E.

    2006-12-12

    Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices are described. In one aspect, an electrical power distribution control method includes providing electrical energy from an electrical power distribution system, applying the electrical energy to a load, providing a plurality of different values for a threshold at a plurality of moments in time and corresponding to an electrical characteristic of the electrical energy, and adjusting an amount of the electrical energy applied to the load responsive to an electrical characteristic of the electrical energy triggering one of the values of the threshold at the respective moment in time.

  4. Development of a smart DC grid model

    NASA Astrophysics Data System (ADS)

    Dalimunthe, Amty Ma'rufah Ardhiyah; Mindara, Jajat Yuda; Panatarani, Camellia; Joni, I. Made

    2016-03-01

    Smart grid and distributed generation should be the solution of the global climate change and the crisis energy of the main source of electrical power generation which is fossil fuel. In order to meet the rising electrical power demand and increasing service quality demands, as well as reduce pollution, the existing power grid infrastructure should be developed into a smart grid and distributed power generation which provide a great opportunity to address issues related to energy efficiency, energy security, power quality and aging infrastructure systems. The conventional of the existing distributed generation system is an AC grid while for a renewable resources requires a DC grid system. This paper explores the model of smart DC grid by introducing a model of smart DC grid with the stable power generation give a minimal and compressed circuitry that can be implemented very cost-effectively with simple components. The PC based application software for controlling was developed to show the condition of the grid and to control the grid become `smart'. The model is then subjected to a severe system perturbation, such as incremental change in loads to test the performance of the system again stability. It is concluded that the system able to detect and controlled the voltage stability which indicating the ability of power system to maintain steady voltage within permissible rangers in normal condition.

  5. Analytical Limit Distributions from Random Power-Law Interactions

    NASA Astrophysics Data System (ADS)

    Zaid, Irwin; Mizuno, Daisuke

    2016-07-01

    Nature is full of power-law interactions, e.g., gravity, electrostatics, and hydrodynamics. When sources of such fields are randomly distributed in space, the superposed interaction, which is what we observe, is naively expected to follow a Gauss or Lévy distribution. Here, we present an analytic expression for the actual distributions that converge to novel limits that are in between these already-known limit distributions, depending on physical parameters, such as the concentration of field sources and the size of the probe used to measure the interactions. By comparing with numerical simulations, the origin of non-Gauss and non-Lévy distributions are theoretically articulated.

  6. Single stage AC-DC converter for Galfenol-based micro-power energy harvesters

    NASA Astrophysics Data System (ADS)

    Cavaroc, Peyton; Curtis, Chandra; Naik, Suketu; Cooper, James

    2014-06-01

    Military based sensor systems are often hindered in operational deployment and/or other capabilities due to limitations in their energy storage elements. Typically operating from lithium based batteries, there is a finite amount of stored energy which the sensor can use to collect and transmit data. As a result, the sensors have reduced sensing and transmission rates. However, coupled with the latest advancements in energy harvesting, these sensors could potentially operate at standard sensing and transition rates as well as dramatically extend lifetimes. Working with the magnetostrictive material Galfenol, we demonstrate the production of enough energy to supplement and recharge a solid state battery thereby overcoming the deficiencies faced by unattended sensors. As with any vibration-based energy harvester, this solution produces an alternating current which needs to be rectified and boosted to a level conducive to recharge the storage element. This paper presents a power converter capable of efficiently converting an ultra-low AC voltage to a solid state charging voltage of 4.1VDC. While we are working with Galfenol transducers as our energy source, this converter may also be applied with any AC producing energy harvester, particularly at operating levels less than 2mW and 200mVAC.

  7. Econophysical anchoring of unimodal power-law distributions

    NASA Astrophysics Data System (ADS)

    Eliazar, Iddo I.; Cohen, Morrel H.

    2013-09-01

    The sciences are abundant with size distributions whose densities have a unimodal shape and power-law tails both at zero and at infinity. The quintessential examples of such unimodal and power-law (UPL) distributions are the sizes of income and wealth in human societies. While the tails of UPL distributions are precisely quantified by their corresponding power-law exponents, their bulks are only qualitatively characterized as unimodal. Consequently, different statistical models of UPL distributions exist, the most popular considering lognormal bulks. In this paper we present a general econophysical framework for UPL distributions termed ‘the anchoring method’. This method: (i) universally approximates UPL distributions via three ‘anchors’ set at zero, at infinity, and at an intermediate point between zero and infinity (e.g. the mode); (ii) is highly versatile and broadly applicable; (iii) encompasses the existing statistical models of UPL distributions as special cases; (iv) facilitates the introduction of new statistical models of UPL distributions and (v) yields a socioeconophysical analysis of UPL distributions.

  8. Dc-To-Dc Converter Uses Reverse Conduction Of MOSFET's

    NASA Technical Reports Server (NTRS)

    Gruber, Robert P.; Gott, Robert W.

    1991-01-01

    In modified high-power, phase-controlled, full-bridge, pulse-width-modulated dc-to-dc converters, switching devices power metal oxide/semiconductor field-effect transistors (MOSFET's). Decreases dissipation of power during switching by eliminating approximately 0.7-V forward voltage drop in anti-parallel diodes. Energy-conversion efficiency increased.

  9. Prediction of heater power distribution in radiative cylindrical furnaces

    SciTech Connect

    Ravichandran, M.; Dilber, I.; Torok, D.

    1999-07-01

    In the design of long radiative cylindrical furnaces, it is important to control the temperature variation along the furnace walls and consequently the temperature distribution in the processed material by selectively adjusting the power input to heater rods located circumferentially around the furnace walls. The heaters are grouped in zones located at different axial locations. By adjusting the power to each zone a specified temperature distribution along the furnace can be attained. The radiative interchange between different axial zones of the furnace affects the temperature distribution; this interchange is also impacted by the shadowing caused by the presence of the load, i.e. the processed material. A desired temperature distribution can only be achieved by selectively changing the power input to the heaters. For an a priori assessment of the commercial viability of using process friendly temperature distributions, it is necessary to determine: (a) the maximum power demand from each zone; (b) if active cooling is inevitable and (c) the bounds on temperature distribution that can be achieved without active cooling. It is therefore extremely useful to be able to predict the input power distribution for achieving desired furnace temperature profiles. For a given power input, the temperature distribution inside the furnace could be obtained by using a general purpose Computational Fluid Dynamics (CFD) software, such as FIDAP. A new methodology is developed within the framework of FIDAP software to eliminate the manual trial and error method. The method is based on obtaining the sensitivity of the temperature at the desired locations of the furnace as a function of the power input to the heating elements. Using these sensitivity coefficients, an iterative scheme is designed to adjust the boundary conditions (power to the heating elements in this case) based on the discrepancy of the solution temperatures from the desired temperature distribution. For each of these

  10. Space station automation of common module power management and distribution

    NASA Technical Reports Server (NTRS)

    Miller, W.; Jones, E.; Ashworth, B.; Riedesel, J.; Myers, C.; Freeman, K.; Steele, D.; Palmer, R.; Walsh, R.; Gohring, J.

    1989-01-01

    The purpose is to automate a breadboard level Power Management and Distribution (PMAD) system which possesses many functional characteristics of a specified Space Station power system. The automation system was built upon 20 kHz ac source with redundancy of the power buses. There are two power distribution control units which furnish power to six load centers which in turn enable load circuits based upon a system generated schedule. The progress in building this specified autonomous system is described. Automation of Space Station Module PMAD was accomplished by segmenting the complete task in the following four independent tasks: (1) develop a detailed approach for PMAD automation; (2) define the software and hardware elements of automation; (3) develop the automation system for the PMAD breadboard; and (4) select an appropriate host processing environment.

  11. Industrial Power Distribution System Reliability Assessment utilizing Markov Approach

    NASA Astrophysics Data System (ADS)

    Guzman-Rivera, Oscar R.

    A method to perform power system reliability analysis using Markov Approach, Reliability Block Diagrams and Fault Tree analysis has been presented. The Markov method we use is a state space model and is based on state diagrams generated for a one line industrial power distribution system. The Reliability block diagram (RBD) method is a graphical and calculation tool used to model the distribution power system of an industrial facility. Quantitative reliability estimations on this work are based on CARMS and Block Sim simulations as well as state space, RBD's and Failure Mode analyses. The power system reliability was assessed and the main contributors to power system reliability have been identified, both qualitatively and quantitatively. Methods to improve reliability have also been provided including redundancies and protection systems that might be added to the system in order to improve reliability.

  12. Performance of Power Converters at Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

    2001-01-01

    Power converters capable of operation at cryogenic temperatures are anticipated to play an important role in the power system architecture of future NASA deep space missions. Design of such converters to survive cryogenic temperatures will improve the power system performance and reduce development and launch costs. Aerospace power systems are mainly a DC distribution network. Therefore, DC/DC and DC/AC converters provide the outputs needed to different loads at various power levels. Recently, research efforts have been performed at the NASA Glenn Research Center (GRC) to design and evaluate DC/DC converters that are capable of operating at cryogenic temperatures. This paper presents a summary of the research performed to evaluate the low temperature performance of five DC/DC converters. Various parameters were investigated as a function of temperature in the range of 20 to -196 C. Data pertaining to the output voltage regulation and efficiency of the converters is presented and discussed.

  13. Optimal Operation of Energy Storage in Power Transmission and Distribution

    NASA Astrophysics Data System (ADS)

    Akhavan Hejazi, Seyed Hossein

    In this thesis, we investigate optimal operation of energy storage units in power transmission and distribution grids. At transmission level, we investigate the problem where an investor-owned independently-operated energy storage system seeks to offer energy and ancillary services in the day-ahead and real-time markets. We specifically consider the case where a significant portion of the power generated in the grid is from renewable energy resources and there exists significant uncertainty in system operation. In this regard, we formulate a stochastic programming framework to choose optimal energy and reserve bids for the storage units that takes into account the fluctuating nature of the market prices due to the randomness in the renewable power generation availability. At distribution level, we develop a comprehensive data set to model various stochastic factors on power distribution networks, with focus on networks that have high penetration of electric vehicle charging load and distributed renewable generation. Furthermore, we develop a data-driven stochastic model for energy storage operation at distribution level, where the distribution of nodal voltage and line power flow are modelled as stochastic functions of the energy storage unit's charge and discharge schedules. In particular, we develop new closed-form stochastic models for such key operational parameters in the system. Our approach is analytical and allows formulating tractable optimization problems. Yet, it does not involve any restricting assumption on the distribution of random parameters, hence, it results in accurate modeling of uncertainties. By considering the specific characteristics of random variables, such as their statistical dependencies and often irregularly-shaped probability distributions, we propose a non-parametric chance-constrained optimization approach to operate and plan energy storage units in power distribution girds. In the proposed stochastic optimization, we consider

  14. Automation of the Athens (Tennessee) electric power distribution system

    SciTech Connect

    Rizy, D.T.; Stovall, J.P.; Usry, G.H.

    1988-01-01

    A large scale distribution automation research and development project has been conducted at the Athens Utilities Board (AUB) in Athens, Tennessee. The project goal was to experiment with the integrated monitoring and control of an entire distribution system from a central distribution control center. The project was sponsored by the U.S. Department of Energy, Office of Energy Storage and Distribution, Electric Energy Systems Program and managed by the Oak Ridge National Laboratory. The experience with the distribution substation monitoring and control, feeder monitoring, voltage and reactive power (vary) control, system (or circuit) reconfiguration for emergency and maintenance situations, and load control are described. A distribution automation applications software package for assessing system configuration, and volt/var control on automated radial distribution feeders was developed and is also described. 8 refs.

  15. Parallel Computing Environments and Methods for Power Distribution System Simulation

    SciTech Connect

    Lu, Ning; Taylor, Zachary T.; Chassin, David P.; Guttromson, Ross T.; Studham, Scott S.

    2005-11-10

    The development of cost-effective high-performance parallel computing on multi-processor super computers makes it attractive to port excessively time consuming simulation software from personal computers (PC) to super computes. The power distribution system simulator (PDSS) takes a bottom-up approach and simulates load at appliance level, where detailed thermal models for appliances are used. This approach works well for a small power distribution system consisting of a few thousand appliances. When the number of appliances increases, the simulation uses up the PC memory and its run time increases to a point where the approach is no longer feasible to model a practical large power distribution system. This paper presents an effort made to port a PC-based power distribution system simulator (PDSS) to a 128-processor shared-memory super computer. The paper offers an overview of the parallel computing environment and a description of the modification made to the PDSS model. The performances of the PDSS running on a standalone PC and on the super computer are compared. Future research direction of utilizing parallel computing in the power distribution system simulation is also addressed.

  16. Distributed photovoltaic generation in residential distribution systems: Impacts on power quality and anti-islanding

    NASA Astrophysics Data System (ADS)

    Mitra, Parag

    The past few decades have seen a consistent growth of distributed PV sources. Distributed PV, like other DG sources, can be located at or near load centers and provide benefits which traditional generation may lack. However, distribution systems were not designed to accommodate such power generation sources as these sources might lead to operational as well as power quality issues. A high penetration of distributed PV resources may lead to bi-directional power flow resulting in voltage swells, increased losses and overloading of conductors. Voltage unbalance is a concern in distribution systems and the effect of single-phase residential PV systems on voltage unbalance needs to be explored. Furthermore, the islanding of DGs presents a technical hurdle towards the seamless integration of DG sources with the electricity grid. The work done in this thesis explores two important aspects of grid inte-gration of distributed PV generation, namely, the impact on power quality and anti-islanding. A test distribution system, representing a realistic distribution feeder in Arizona is modeled to study both the aforementioned aspects. The im-pact of distributed PV on voltage profile, voltage unbalance and distribution sys-tem primary losses are studied using CYMDIST. Furthermore, a PSCAD model of the inverter with anti-island controls is developed and the efficacy of the anti-islanding techniques is studied. Based on the simulations, generalized conclusions are drawn and the problems/benefits are elucidated.

  17. The Effects of Transients on Photospheric and Chromospheric Power Distributions

    NASA Astrophysics Data System (ADS)

    Samanta, T.; Henriques, V. M. J.; Banerjee, D.; Krishna Prasad, S.; Mathioudakis, M.; Jess, D.; Pant, V.

    2016-09-01

    We have observed a quiet-Sun region with the Swedish 1 m Solar Telescope equipped with the CRISP Imaging SpectroPolarimeter. High-resolution, high-cadence, Hα line scanning images were taken to observe different layers of the solar atmosphere from the photosphere to upper chromosphere. We study the distribution of power in different period bands at different heights. Power maps of the upper photosphere and the lower chromosphere show suppressed power surrounding the magnetic-network elements, known as “magnetic shadows.” These also show enhanced power close to the photosphere, traditionally referred to as “power halos.” The interaction between acoustic waves and inclined magnetic fields is generally believed to be responsible for these two effects. In this study we explore whether small-scale transients can influence the distribution of power at different heights. We show that the presence of transients, like mottles, Rapid Blueshifted Excursions (RBEs), and Rapid Redshifted Excursions (RREs), can strongly influence the power maps. The short and finite lifetime of these events strongly affects all power maps, potentially influencing the observed power distribution. We show that Doppler-shifted transients like RBEs and RREs that occur ubiquitously can have a dominant effect on the formation of the power halos in the quiet Sun. For magnetic shadows, transients like mottles do not seem to have a significant effect on the power suppression around 3 minutes, and wave interaction may play a key role here. Our high-cadence observations reveal that flows, waves, and shocks manifest in the presence of magnetic fields to form a nonlinear magnetohydrodynamic system.

  18. Power laws, discontinuities and regional city size distributions

    USGS Publications Warehouse

    Garmestani, A.S.; Allen, C.R.; Gallagher, C.M.

    2008-01-01

    Urban systems are manifestations of human adaptation to the natural environment. City size distributions are the expression of hierarchical processes acting upon urban systems. In this paper, we test the entire city size distributions for the southeastern and southwestern United States (1990), as well as the size classes in these regions for power law behavior. We interpret the differences in the size of the regional city size distributions as the manifestation of variable growth dynamics dependent upon city size. Size classes in the city size distributions are snapshots of stable states within urban systems in flux. ?? 2008.

  19. Forty-seventh annual power distribution conference, 1994

    SciTech Connect

    Not Available

    1994-01-01

    This is a collection of papers presented at the forty-seventh annual Power Distribution Conference in 1994. The topics of the papers include recent developments in distribution grounding, partial discharge analysis of electrical machinery, insulating fluids analysis as a basis for a complete transformer monitoring program, environmental and regulatory issues regarding the use of silicone transformer fluids, locating and identifying harmonic sources, optimizing distribution operations resources, surface launch directional boring units, electrical supply to Dallas/Fort Worth international airport, a microprocessor-based digital feeder monitor with high-impedance fault detection, a modern review of distribution system protective coordination, and Ski Apache electric service improvements.

  20. Radiation effects on DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Zhang, Dexin; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2000-01-01

    DC-DC switching converters are circuits that can be used to convert a DC voltage of one value to another by switching action. They are increasing being used in space systems. Most of the popular DC-DC switching converters utilize power MOSFETs. However power MOSFETs, when subjected to radiation, are susceptible to degradation of device characteristics or catastrophic failure. This work focuses on the effects of total ionizing dose on converter performance. Four fundamental switching converters (buck converter, buck-boost converter, cuk converter, and flyback converter) were built using Harris IRF250 power MOSFETs. These converters were designed for converting an input of 60 volts to an output of about 12 volts with a switching frequency of 100 kHz. The four converters were irradiated with a Co-60 gamma source at dose rate of 217 rad/min. The performances of the four converters were examined during the exposure to the radiation. The experimental results show that the output voltage of the converters increases as total dose increases. However, the increases of the output voltage were different for the four different converters, with the buck converter and cuk converter the highest and the flyback converter the lowest. We observed significant increases in output voltage for cuk converter at a total dose of 24 krad (si).

  1. Comparison of Wind Power and Load Forecasting Error Distributions: Preprint

    SciTech Connect

    Hodge, B. M.; Florita, A.; Orwig, K.; Lew, D.; Milligan, M.

    2012-07-01

    The introduction of large amounts of variable and uncertain power sources, such as wind power, into the electricity grid presents a number of challenges for system operations. One issue involves the uncertainty associated with scheduling power that wind will supply in future timeframes. However, this is not an entirely new challenge; load is also variable and uncertain, and is strongly influenced by weather patterns. In this work we make a comparison between the day-ahead forecasting errors encountered in wind power forecasting and load forecasting. The study examines the distribution of errors from operational forecasting systems in two different Independent System Operator (ISO) regions for both wind power and load forecasts at the day-ahead timeframe. The day-ahead timescale is critical in power system operations because it serves the unit commitment function for slow-starting conventional generators.

  2. Edge effect on the power law distribution of granular avalanches.

    PubMed

    Lorincz, Kinga A; Wijngaarden, Rinke J

    2007-10-01

    Many punctuated phenomena in nature are claimed [e.g., by the theory of self-organized criticality (SOC)] to be power-law distributed. In our experiments on a three-dimensional pile of long-grained rice, we find that by only changing the boundary condition of the system, we switch from such power-law-distributed avalanche sizes to quasiperiodic system-spanning avalanches. Conversely, by removing ledges the incidence of system-spanning avalanches is significantly reduced. This may offer a perspective on new avalanche prevention schemes. In addition, our findings may help to explain why the archetype of SOC, the sandpile, was found to have power-law-distributed avalanches in some experiments, while in other experiments quasiperiodic system-spanning avalanches were found.

  3. Benefits of Power Electronic Interfaces for Distributed Energy Systems

    SciTech Connect

    Kroposki, B.; Pink, C.; DeBlasio, R.; Thomas, H.; Simoes, M.; Sen, P. K.

    2006-01-01

    Optimization of overall electrical system performance is important for the long-term economic viability of distributed energy (DE) systems. With the increasing use of DE systems in industry and its technological advancement, it is becoming more important to understand the integration of these systems with the electric power systems. New markets and benefits for distributed energy applications include the ability to provide ancillary services, improve energy efficiency, enhance power system reliability, and allow customer choice. Advanced power electronic (PE) interfaces will allow DE systems to provide increased functionality through improved power quality and voltage/VAR support, increase electrical system compatibility by reducing the fault contributions, and flexibility in operations with various other DE sources, while reducing overall interconnection costs. This paper examines the system integration and optimization issues associated with DE systems and show the benefits of using PE interfaces for such applications.

  4. Space station automation of common module power management and distribution, volume 2

    NASA Technical Reports Server (NTRS)

    Ashworth, B.; Riedesel, J.; Myers, C.; Jakstas, L.; Smith, D.

    1990-01-01

    The new Space Station Module Power Management and Distribution System (SSM/PMAD) testbed automation system is described. The subjects discussed include testbed 120 volt dc star bus configuration and operation, SSM/PMAD automation system architecture, fault recovery and management expert system (FRAMES) rules english representation, the SSM/PMAD user interface, and the SSM/PMAD future direction. Several appendices are presented and include the following: SSM/PMAD interface user manual version 1.0, SSM/PMAD lowest level processor (LLP) reference, SSM/PMAD technical reference version 1.0, SSM/PMAD LLP visual control logic representation's (VCLR's), SSM/PMAD LLP/FRAMES interface control document (ICD) , and SSM/PMAD LLP switchgear interface controller (SIC) ICD.

  5. System-wide power management control via clock distribution network

    DOEpatents

    Coteus, Paul W.; Gara, Alan; Gooding, Thomas M.; Haring, Rudolf A.; Kopcsay, Gerard V.; Liebsch, Thomas A.; Reed, Don D.

    2015-05-19

    An apparatus, method and computer program product for automatically controlling power dissipation of a parallel computing system that includes a plurality of processors. A computing device issues a command to the parallel computing system. A clock pulse-width modulator encodes the command in a system clock signal to be distributed to the plurality of processors. The plurality of processors in the parallel computing system receive the system clock signal including the encoded command, and adjusts power dissipation according to the encoded command.

  6. Electrical Power Distribution and Control Modeling and Analysis

    NASA Technical Reports Server (NTRS)

    Fu, Johnny S.; Liffring, Mark; Mehdi, Ishaque S.

    2001-01-01

    This slide presentation reviews the use of Electrical Power Distribution and Control (EPD&C) Modeling and how modeling can support analysis. The presentation discusses using the EASY5 model to simulate and analyze the Space Shuttle Electric Auxiliary Power Unit. Diagrams of the model schematics are included, as well as graphs of the battery cell impedance, hydraulic load dynamics, and EPD&C response to hydraulic load variations.

  7. Power law tails in the Italian personal income distribution

    NASA Astrophysics Data System (ADS)

    Clementi, F.; Gallegati, M.

    2005-05-01

    We investigate the shape of the Italian personal income distribution using microdata from the Survey on Household Income and Wealth, made publicly available by the Bank of Italy for the years 1977-2002. We find that the upper tail of the distribution is consistent with a Pareto-power law type distribution, while the rest follows a two-parameter lognormal distribution. The results of our analysis show a shift of the distribution and a change of the indexes specifying it over time. As regards the first issue, we test the hypothesis that the evolution of both gross domestic product and personal income is governed by similar mechanisms, pointing to the existence of correlation between these quantities. The fluctuations of the shape of income distribution are instead quantified by establishing some links with the business cycle phases experienced by the Italian economy over the years covered by our dataset.

  8. DETERMINATION OF INVENTORIES AND POWER DISTRIBUTIONS FOR THE NSBR.

    SciTech Connect

    HANSON, A.L.; DIAMOND, D.J.

    2005-09-12

    This memo presents the details of the methodology for developing fuel inventories for the NBSR along with power distributions predicted with this set of inventories. Several improvements have been made to the MCNP model of the NBSR since a set of calculations was performed in 2002 in support of the NBSR relicensing and SAR update. One of the most significant changes in the model was to divide the fuel elements into upper and lower halves so the effects of uneven burn between the two halves (due to the shim arms) can be determined. The present set of power distributions are provided for comparison with the previous safety analyses.

  9. Radiation Effects on DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Zhang, De-Xin; AbdulMazid, M. D.; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2001-01-01

    In this work, several DC-DC converters were designed and built. The converters are Buck Buck-Boost, Cuk, Flyback, and full-bridge zero-voltage switched. The total ionizing dose radiation and single event effects on the converters were investigated. The experimental results for the TID effects tests show that the voltages of the Buck Buck-Boost, Cuk, and Flyback converters increase as total dose increased when using power MOSFET IRF250 as a switching transistor. The change in output voltage with total dose is highest for the Buck converter and the lowest for Flyback converter. The trend of increase in output voltages with total dose in the present work agrees with those of the literature. The trends of the experimental results also agree with those obtained from PSPICE simulation. For the full-bridge zero-voltage switch converter, it was observed that the dc-dc converter with IRF250 power MOSFET did not show a significant change of output voltage with total dose. In addition, for the dc-dc converter with FSF254R4 radiation-hardened power MOSFET, the output voltage did not change significantly with total dose. The experimental results were confirmed by PSPICE simulation that showed that FB-ZVS converter with IRF250 power MOSFET's was not affected with the increase in total ionizing dose. Single Event Effects (SEE) radiation tests were performed on FB-ZVS converters. It was observed that the FB-ZVS converter with the IRF250 power MOSFET, when the device was irradiated with Krypton ion with ion-energy of 150 MeV and LET of 41.3 MeV-square cm/mg, the output voltage increased with the increase in fluence. However, for Krypton with ion-energy of 600 MeV and LET of 33.65 MeV-square cm/mg, and two out of four transistors of the converter were permanently damaged. The dc-dc converter with FSF254R4 radiation hardened power MOSFET's did not show significant change at the output voltage with fluence while being irradiated by Krypton with ion energy of 1.20 GeV and LET of 25

  10. Electric power scheduling - A distributed problem-solving approach

    NASA Technical Reports Server (NTRS)

    Mellor, Pamela A.; Dolce, James L.; Krupp, Joseph C.

    1990-01-01

    Space Station Freedom's power system, along with the spacecraft's other subsystems, needs to carefully conserve its resources and yet strive to maximize overall Station productivity. Due to Freedom's distributed design, each subsystem must work cooperatively within the Station community. There is a need for a scheduling tool which will preserve this distributed structure, allow each subsystem the latitude to satisfy its own constraints, and preserve individual value systems while maintaining Station-wide integrity.

  11. Proposal of an Innovative Electric Power Distribution System based on Packet Power Transactions

    NASA Astrophysics Data System (ADS)

    Inoue, Jun; Fujii, Yasumasa

    Recently, the introduction of decentralized generators, such as photovoltaic power generations, has been promoted rapidly. In the future, extensive use of PV is thought to give rise to the daytime surplus electricity, and a household will manage the surplus electricity rationally. The purpose of this research is to propose an innovative electric power distribution system based on packet power transactions. First, this paper explains distributed markets of which the price can easily reflect the geographical diversity of renewable energy availability and load curve characteristic within the local area. Second, this paper exemplifies the specific electronic circuit that makes pulse-shaped power transmission to develop the packet power distribution system. Finally, this paper shows the results of multi-agent simulations of electricity trading to evaluate the usefulness of the proposed system.

  12. Wind Power Forecasting Error Distributions: An International Comparison; Preprint

    SciTech Connect

    Hodge, B. M.; Lew, D.; Milligan, M.; Holttinen, H.; Sillanpaa, S.; Gomez-Lazaro, E.; Scharff, R.; Soder, L.; Larsen, X. G.; Giebel, G.; Flynn, D.; Dobschinski, J.

    2012-09-01

    Wind power forecasting is expected to be an important enabler for greater penetration of wind power into electricity systems. Because no wind forecasting system is perfect, a thorough understanding of the errors that do occur can be critical to system operation functions, such as the setting of operating reserve levels. This paper provides an international comparison of the distribution of wind power forecasting errors from operational systems, based on real forecast data. The paper concludes with an assessment of similarities and differences between the errors observed in different locations.

  13. DC Microgrids Scoping Study. Estimate of Technical and Economic Benefits

    SciTech Connect

    Backhaus, Scott N.; Swift, Gregory William; Chatzivasileiadis, Spyridon; Tschudi, William; Glover, Steven; Starke, Michael; Wang, Jianhui; Yue, Meng; Hammerstrom, Donald

    2015-03-23

    Microgrid demonstrations and deployments are expanding in US power systems and around the world. Although goals are specific to each site, these microgrids have demonstrated the ability to provide higher reliability and higher power quality than utility power systems and improved energy utilization. The vast majority of these microgrids are based on AC power transfer because this has been the traditionally dominant power delivery scheme. Independently, manufacturers, power system designers and researchers are demonstrating and deploying DC power distribution systems for applications where the end-use loads are natively DC, e.g., computers, solid-state lighting, and building networks. These early DC applications may provide higher efficiency, added flexibility, reduced capital costs over their AC counterparts. Further, when onsite renewable generation, electric vehicles and storage systems are present, DC-based microgrids may offer additional benefits. Early successes from these efforts raises a question - can a combination of microgrid concepts and DC distribution systems provide added benefits beyond what has been achieved individually?

  14. Evaluation of power control concepts using the PMAD systems test bed. [Power Management and Distribution

    NASA Technical Reports Server (NTRS)

    Beach, R. F.; Kimnach, G. L.; Jett, T. A.; Trash, L. M.

    1989-01-01

    The Lewis Research Center's Power Management and Distribution (PMAD) System testbed and its use in the evaluation of control concepts applicable to the NASA Space Station Freedom electric power system (EPS) are described. The facility was constructed to allow testing of control hardware and software in an environment functionally similar to the space station electric power system. Control hardware and software have been developed to allow operation of the testbed power system in a manner similar to a supervisory control and data acquisition (SCADA) system employed by utility power systems for control. The system hardware and software are described.

  15. A Distributed Cooperative Power Allocation Method for Campus Buildings

    SciTech Connect

    Hao, He; Sun, Yannan; Carroll, Thomas E.; Somani, Abhishek

    2015-09-01

    We propose a coordination algorithm for cooperative power allocation among a collection of commercial buildings within a campus. We introduced thermal and power models of a typical commercial building Heating, Ventilation, and Air Conditioning (HVAC) system, and utilize model predictive control to characterize their power flexibility. The power allocation problem is formulated as a cooperative game using the Nash Bargaining Solution (NBS) concept, in which buildings collectively maximize the product of their utilities subject to their local flexibility constraints and a total power limit set by the campus coordinator. To solve the optimal allocation problem, a distributed protocol is designed using dual decomposition of the Nash bargaining problem. Numerical simulations are performed to demonstrate the efficacy of our proposed allocation method

  16. Hybrid electric vehicle power management system

    SciTech Connect

    Bissontz, Jay E.

    2015-08-25

    Level voltage levels/states of charge are maintained among a plurality of high voltage DC electrical storage devices/traction battery packs that are arrayed in series to support operation of a hybrid electric vehicle drive train. Each high voltage DC electrical storage device supports a high voltage power bus, to which at least one controllable load is connected, and at least a first lower voltage level electrical distribution system. The rate of power transfer from the high voltage DC electrical storage devices to the at least first lower voltage electrical distribution system is controlled by DC-DC converters.

  17. Development of a 10 kW High Temperature High Power Density Three-Phase AC-DC-AC SiC Converter

    SciTech Connect

    Ning, Puqi

    2012-01-01

    This paper presents the development and experimental performance of a 10 kW, all SiC, 250 C junction temperature high-power-density three-phase ac-dc-ac converter. The electromagnetic interference filter, thermal system, high temperature package, and gate drive design are discussed in detail. Finally, tests confirming the feasibility and validating the theoretical basis of the prototype converter system are described.

  18. Power-law time distribution of large earthquakes.

    PubMed

    Mega, Mirko S; Allegrini, Paolo; Grigolini, Paolo; Latora, Vito; Palatella, Luigi; Rapisarda, Andrea; Vinciguerra, Sergio

    2003-05-01

    We study the statistical properties of time distribution of seismicity in California by means of a new method of analysis, the diffusion entropy. We find that the distribution of time intervals between a large earthquake (the main shock of a given seismic sequence) and the next one does not obey Poisson statistics, as assumed by the current models. We prove that this distribution is an inverse power law with an exponent mu=2.06+/-0.01. We propose the long-range model, reproducing the main properties of the diffusion entropy and describing the seismic triggering mechanisms induced by large earthquakes.

  19. 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.

  20. New-type cable accessories for power distribution

    SciTech Connect

    Sanjo, K.; Kawano, K.; Shiraoka, K.; Yasuda, N.; Yatsuka, K.

    1982-12-01

    This paper describes new types of cable accessories for improving the reliability of power distribution cable systems. The practical development of a 25kV-class cable termination, and a waterproof sleeve for cable joints based on heat-shrinkable components made of irradiated polyolefine is discussed. Furthermore, the theoretical and practical data are given.

  1. HEMP interaction with an electric power distribution circuit. Final report

    SciTech Connect

    Zaininger, H.W.; Jaszewski, G.M.

    1985-08-01

    A high altitude nuclear burst, detonated at a height of 50 km or more, causes two types of electromagnetic pulses, high altitude EMP (HEMP) and magnetohydrodynamic EMP, which will interact with electric power systems. Previous work indicated that millions of miles of electric distribution systems in the United States may be especially vulnerable to HEMP incident simultaneously throughout large portions of the United States. Purpose of this work was to perform an initial assessment of HEMP induced surges on a simplified electric distribution system. This report presents the assumptions, methodology, and resulting induced transient voltages and currents at various points in the distribution circuit in the microsecond timeframe, considering the impacts of HEMP incident simultaneously throughout the distribution system for a range of parametric conditions. Results of this work suggest that EMP could induce voltage transients that far exceed the basic insulation level (BIL) of distribution systems and that a more detailed analysis is warranted.

  2. Analytical Limit Distributions from Random Power-Law Interactions.

    PubMed

    Zaid, Irwin; Mizuno, Daisuke

    2016-07-15

    Nature is full of power-law interactions, e.g., gravity, electrostatics, and hydrodynamics. When sources of such fields are randomly distributed in space, the superposed interaction, which is what we observe, is naively expected to follow a Gauss or Lévy distribution. Here, we present an analytic expression for the actual distributions that converge to novel limits that are in between these already-known limit distributions, depending on physical parameters, such as the concentration of field sources and the size of the probe used to measure the interactions. By comparing with numerical simulations, the origin of non-Gauss and non-Lévy distributions are theoretically articulated. PMID:27472105

  3. Occurrence and Distribution of Organic Wastewater Compounds in Rock Creek Park, Washington, D.C., 2007-08

    USGS Publications Warehouse

    Phelan, Daniel J.; Miller, Cherie V.

    2010-01-01

    The U.S. Geological Survey, and the National Park Service Police Aviation Group, conducted a high-resolution, low-altitude aerial thermal infrared survey of the Washington, D.C. section of Rock Creek Basin within the Park boundaries to identify specific locations where warm water was discharging from seeps or pipes to the creek. Twenty-three stream sites in Rock Creek Park were selected based on the thermal infrared images. Sites were sampled during the summers of 2007 and 2008 for the analysis of organic wastewater compounds to verify potential sources of sewage and other anthropogenic wastewater. Two sets of stormwater samples were collected, on June 27-28 and September 6, 2008, at the Rock Creek at Joyce Road water-quality station using an automated sampler that began sampling when a specified stage threshold value was exceeded. Passive-sampler devices that accumulate organic chemicals over the duration of deployment were placed in July 2008 at the five locations that had the greatest number of detections of organic wastewater compounds from the June 2007 base-flow sampling. During the 2007 base-flow synoptic sampling, there were ubiquitous low-level detections of dissolved organic wastewater indicator compounds such as DEET, caffeine, HHCB, and organophosphate flame retardants at more than half of the 23 sites sampled in Rock Creek Park. Concentrations of DEET and caffeine in the tributaries to Rock Creek were variable, but in the main stem of Rock Creek, the concentrations were constant throughout the length of the creek, which likely reflects a distributed source. Organophosphate flame retardants in the main stem of Rock Creek were detected at estimated concentrations of 0.2 micrograms per liter or less, and generally did not increase with distance downstream. Overall, concentrations of most wastewater indicators in whole-water samples in the Park were similar to the concentrations found at the upstream sampling station at the Maryland/District of Columbia

  4. Modeling and Verification of Distributed Generation and Voltage Regulation Equipment for Unbalanced Distribution Power Systems; Annual Subcontract Report, June 2007

    SciTech Connect

    Davis, M. W.; Broadwater, R.; Hambrick, J.

    2007-07-01

    This report summarizes the development of models for distributed generation and distribution circuit voltage regulation equipment for unbalanced power systems and their verification through actual field measurements.

  5. Electron beam machining using rotating and shaped beam power distribution

    DOEpatents

    Elmer, John W.; O'Brien, Dennis W.

    1996-01-01

    An apparatus and method for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: 1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and 2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1000 .mu.m (1 mm or larger), compared to the 250 .mu.m diameter of laser drilling.

  6. Electron beam machining using rotating and shaped beam power distribution

    DOEpatents

    Elmer, J.W.; O`Brien, D.W.

    1996-07-09

    An apparatus and method are disclosed for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: (1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and (2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1,000 {micro}m (1 mm or larger), compared to the 250 {micro}m diameter of laser drilling. 5 figs.

  7. Statistical Models of Power-law Distributions in Homogeneous Plasmas

    SciTech Connect

    Roth, Ilan

    2011-01-04

    A variety of in-situ measurements in space plasmas point out to an intermittent formation of distribution functions with elongated tails and power-law at high energies. Power-laws form ubiquitous signature of many complex systems, plasma being a good example of a non-Boltzmann behavior for distribution functions of energetic particles. Particles, which either undergo mutual collisions or are scattered in phase space by electromagnetic fluctuations, exhibit statistical properties, which are determined by the transition probability density function of a single interaction, while their non-asymptotic evolution may determine the observed high-energy populations. It is shown that relaxation of the Brownian motion assumptions leads to non-analytical characteristic functions and to generalization of the Fokker-Planck equation with fractional derivatives that result in power law solutions parameterized by the probability density function.

  8. Exploring empowerment in settings: mapping distributions of network power.

    PubMed

    Neal, Jennifer Watling

    2014-06-01

    This paper brings together two trends in the empowerment literature-understanding empowerment in settings and understanding empowerment as relational-by examining what makes settings empowering from a social network perspective. Specifically, extending Neal and Neal's (Am J Community Psychol 48(3/4):157-167, 2011) conception of network power, an empowering setting is defined as one in which (1) actors have existing relationships that allow for the exchange of resources and (2) the distribution of network power among actors in the setting is roughly equal. The paper includes a description of how researchers can examine distributions of network power in settings. Next, this process is illustrated in both an abstract example and using empirical data on early adolescents' peer relationships in urban classrooms. Finally, implications for theory, methods, and intervention related to understanding empowering settings are explored.

  9. Distributed Power Flow Control: Distributed Power Flow Control using Smart Wires for Energy Routing

    SciTech Connect

    2012-04-24

    GENI Project: Smart Wire Grid is developing a solution for controlling power flow within the electric grid to better manage unused and overall transmission capacity. The 300,000 miles of high-voltage transmission line in the U.S. today are congested and inefficient, with only around 50% of all transmission capacity utilized at any given time. Increased consumer demand should be met in part with more efficient and an economical power flow. Smart Wire Grid’s devices clamp onto existing transmission lines and control the flow of power within—much like how internet routers help allocate bandwidth throughout the web. Smart wires could support greater use of renewable energy by providing more consistent control over how that energy is routed within the grid on a real-time basis. This would lessen the concerns surrounding the grid’s inability to effectively store intermittent energy from renewables for later use.

  10. Distribution of Acoustic Power Spectra for an Isolated Helicopter Fuselage

    NASA Astrophysics Data System (ADS)

    Kusyumov, A. N.; Mikhailov, S. A.; Garipova, L. I.; Batrakov, A. S.; Barakos, G.

    2016-03-01

    The broadband aerodynamic noise can be studied, assuming isotropic flow, turbulence and decay. Proudman's approach allows practical calculations of noise based on CFD solutions of RANS or URANS equations at the stage of post processing and analysis of the solution. Another aspect is the broadband acoustic spectrum and the distribution of acoustic power over a range of frequencies. The acoustic energy spectrum distribution in isotropic turbulence is non monotonic and has a maximum at a certain value of Strouhal number. In the present work the value of acoustic power peak frequency is determined using a prescribed form of acoustic energy spectrum distribution presented in papers by S. Sarkar and M. Y. Hussaini and by G. M. Lilley. CFD modelling of the flow around isolated helicopter fuselage model was considered using the HMB CFD code and the RANS equations.

  11. Learning geotemporal nonstationary failure and recovery of power distribution.

    PubMed

    Wei, Yun; Ji, Chuanyi; Galvan, Floyd; Couvillon, Stephen; Orellana, George; Momoh, James

    2014-01-01

    Smart energy grid is an emerging area for new applications of machine learning in a nonstationary environment. Such a nonstationary environment emerges when large-scale failures occur at power networks because of external disruptions such as hurricanes and severe storms. Power distribution networks lie at the edge of the grid, and are especially vulnerable to external disruptions. Quantifiable approaches are lacking and needed to learn nonstationary behaviors of large-scale failure and recovery of power distribution. This paper studies such nonstationary behaviors in three aspects. First, a novel formulation is derived for an entire life cycle of large-scale failure and recovery of power distribution. Second, spatial-temporal models of failure and recovery of power distribution are developed as geolocation-based multivariate nonstationary GI(t)/G(t)/∞ queues. Third, the nonstationary spatial-temporal models identify a small number of parameters to be learned. Learning is applied to two real-life examples of large-scale disruptions. One is from Hurricane Ike, where data from an operational network is exact on failures and recoveries. The other is from Hurricane Sandy, where aggregated data is used for inferring failure and recovery processes at one of the impacted areas. Model parameters are learned using real data. Two findings emerge as results of learning: 1) failure rates behave similarly at the two different provider networks for two different hurricanes but differently at the geographical regions and 2) both the rapid and slow-recovery are present for Hurricane Ike but only slow recovery is shown for a regional distribution network from Hurricane Sandy.

  12. Time-dependent distribution functions and resulting synthetic NPA spectra in C-Mod calculated with the CQL3D-Hybrid-FOW, AORSA full-wave, and DC Lorentz codes

    NASA Astrophysics Data System (ADS)

    Harvey, R. W.; Petrov, Yu.; Jaeger, E. F.; Berry, L. A.; Bonoli, P. T.; Bader, A.

    2015-12-01

    A time-dependent simulation of C-Mod pulsed TCRF power is made obtaining minority hydrogen ion distributions with the CQL3D-Hybrid-FOW finite-orbit-width Fokker-Planck code. Cyclotron-resonant TCRF fields are calculated with the AORSA full wave code. The RF diffusion coefficients used in CQL3D are obtained with the DC Lorentz gyro-orbit code for perturbed particle trajectories in the combined equilibrium and TCRF electromagnetic fields. Prior results with a zero-banana-width simulation using the CQL3D/AORSA/DC time-cycles showed a pronounced enhancement of the H distribution in the perpendicular velocity direction compared to results obtained from Stix's quasilinear theory, and this substantially increased the rampup rate of the observed vertically-viewed neutral particle analyzer (NPA) flux, in general agreement with experiment. However, ramp down of the NPA flux after the pulse, remained long compared to the experiment. The present study compares the new FOW results, including relevant gyro-radius effects, to determine the importance of these new effects on the the NPA time-dependence.

  13. A Distributed Approach to Maximum Power Point Tracking for Photovoltaic Submodule Differential Power Processing

    SciTech Connect

    Qin, SB; Cady, ST; Dominguez-Garcia, AD; Pilawa-Podgurski, RCN

    2015-04-01

    This paper presents the theory and implementation of a distributed algorithm for controlling differential power processing converters in photovoltaic (PV) applications. This distributed algorithm achieves true maximum power point tracking of series-connected PV submodules by relying only on local voltage measurements and neighbor-to-neighbor communication between the differential power converters. Compared to previous solutions, the proposed algorithm achieves reduced number of perturbations at each step and potentially faster tracking without adding extra hardware; all these features make this algorithm well-suited for long submodule strings. The formulation of the algorithm, discussion of its properties, as well as three case studies are presented. The performance of the distributed tracking algorithm has been verified via experiments, which yielded quantifiable improvements over other techniques that have been implemented in practice. Both simulations and hardware experiments have confirmed the effectiveness of the proposed distributed algorithm.

  14. Advanced Propulsion Power Distribution System for Next Generation Electric/Hybrid Vehicle. Phase 1; Preliminary System Studies

    NASA Technical Reports Server (NTRS)

    Bose, Bimal K.; Kim, Min-Huei

    1995-01-01

    The report essentially summarizes the work performed in order to satisfy the above project objective. In the beginning, different energy storage devices, such as battery, flywheel and ultra capacitor are reviewed and compared, establishing the superiority of the battery. Then, the possible power sources, such as IC engine, diesel engine, gas turbine and fuel cell are reviewed and compared, and the superiority of IC engine has been established. Different types of machines for drive motor/engine generator, such as induction machine, PM synchronous machine and switched reluctance machine are compared, and the induction machine is established as the superior candidate. Similar discussion was made for power converters and devices. The Insulated Gate Bipolar Transistor (IGBT) appears to be the most superior device although Mercury Cadmium Telluride (MCT) shows future promise. Different types of candidate distribution systems with the possible combinations of power and energy sources have been discussed and the most viable system consisting of battery, IC engine and induction machine has been identified. Then, HFAC system has been compared with the DC system establishing the superiority of the former. The detailed component sizing calculations of HFAC and DC systems reinforce the superiority of the former. A preliminary control strategy has been developed for the candidate HFAC system. Finally, modeling and simulation study have been made to validate the system performance. The study in the report demonstrates the superiority of HFAC distribution system for next generation electric/hybrid vehicle.

  15. Distributed renewable power from biomass and other waste fuels

    NASA Astrophysics Data System (ADS)

    Lyons, Chris

    2012-03-01

    The world population is continually growing and putting a burden on our fossil fuels. These fossil fuels such as coal, oil and natural gas are used for a variety of critical needs such as power production and transportation. While significant environmental improvements have been made, the uses of these fuels are still causing significant ecological impacts. Coal power production efficiency has not improved over the past thirty years and with relatively cheap petroleum cost, transportation mileage has not improved significantly either. With the demand for these fossil fuels increasing, ultimately price will also have to increase. This presentation will evaluate alternative power production methods using localized distributed generation from biomass, municipal solid waste and other waste sources of organic materials. The presentation will review various gasification processes that produce a synthetic gas that can be utilized as a fuel source in combustion turbines for clean and efficient combined heat and power. This fuel source can produce base load renewable power. In addition tail gases from the production of bio-diesel and methanol fuels can be used to produce renewable power. Being localized can reduce the need for long and costly transmission lines making the production of fuels and power from waste a viable alternative energy source for the future.

  16. Preparation of Power Distribution System for High Penetration of Renewable Energy Part I. Dynamic Voltage Restorer for Voltage Regulation Pat II. Distribution Circuit Modeling and Validation

    NASA Astrophysics Data System (ADS)

    Khoshkbar Sadigh, Arash

    Part I: Dynamic Voltage Restorer In the present power grids, voltage sags are recognized as a serious threat and a frequently occurring power-quality problem and have costly consequence such as sensitive loads tripping and production loss. Consequently, the demand for high power quality and voltage stability becomes a pressing issue. Dynamic voltage restorer (DVR), as a custom power device, is more effective and direct solutions for "restoring" the quality of voltage at its load-side terminals when the quality of voltage at its source-side terminals is disturbed. In the first part of this thesis, a DVR configuration with no need of bulky dc link capacitor or energy storage is proposed. This fact causes to reduce the size of the DVR and increase the reliability of the circuit. In addition, the proposed DVR topology is based on high-frequency isolation transformer resulting in the size reduction of transformer. The proposed DVR circuit, which is suitable for both low- and medium-voltage applications, is based on dc-ac converters connected in series to split the main dc link between the inputs of dc-ac converters. This feature makes it possible to use modular dc-ac converters and utilize low-voltage components in these converters whenever it is required to use DVR in medium-voltage application. The proposed configuration is tested under different conditions of load power factor and grid voltage harmonic. It has been shown that proposed DVR can compensate the voltage sag effectively and protect the sensitive loads. Following the proposition of the DVR topology, a fundamental voltage amplitude detection method which is applicable in both single/three-phase systems for DVR applications is proposed. The advantages of proposed method include application in distorted power grid with no need of any low-pass filter, precise and reliable detection, simple computation and implementation without using a phased locked loop and lookup table. The proposed method has been verified

  17. Fiber-Optic Distribution Of Pulsed Power To Multiple Sensors

    NASA Technical Reports Server (NTRS)

    Kirkham, Harold

    1996-01-01

    Optoelectronic systems designed according to time-sharing scheme distribute optical power to multiple integrated-circuit-based sensors in fiber-optic networks. Networks combine flexibility of electronic sensing circuits with advantage of electrical isolation afforded by use of optical fibers instead of electrical conductors to transmit both signals and power. Fiber optics resist corrosion and immune to electromagnetic interference. Sensor networks of this type useful in variety of applications; for example, in monitoring strains in aircraft, buildings, and bridges, and in monitoring and controlling shapes of flexible structures.

  18. Power management and distribution considerations for a lunar base

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Coleman, Anthony S.

    1991-01-01

    Design philosophies and technology needs for the power management and distribution (PMAD) portion of a lunar base power system are discussed. A process is described whereby mission planners may proceed from a knowledge of the PMAD functions and mission performance requirements to a definition of design options and technology needs. Current research efforts at the NASA LRC to meet the PMAD system needs for a Lunar base are described. Based on the requirements, the lunar base PMAD is seen as best being accomplished by a utility like system, although with some additional demands including autonomous operation and scheduling and accurate, predictive modeling during the design process.

  19. Electric power scheduling: A distributed problem-solving approach

    NASA Technical Reports Server (NTRS)

    Mellor, Pamela A.; Dolce, James L.; Krupp, Joseph C.

    1990-01-01

    Space Station Freedom's power system, along with the spacecraft's other subsystems, needs to carefully conserve its resources and yet strive to maximize overall Station productivity. Due to Freedom's distributed design, each subsystem must work cooperatively within the Station community. There is a need for a scheduling tool which will preserve this distributed structure, allow each subsystem the latitude to satisfy its own constraints, and preserve individual value systems while maintaining Station-wide integrity. The value-driven free-market economic model is such a tool.

  20. Power-exponential velocity distributions in disordered porous media

    NASA Astrophysics Data System (ADS)

    Matyka, Maciej; Gołembiewski, Jarosław; Koza, Zbigniew

    2016-01-01

    Velocity distribution functions link the micro- and macro-level theories of fluid flow through porous media. Here we study them for the fluid absolute velocity and its longitudinal and lateral components relative to the macroscopic flow direction in a model of a random porous medium. We claim that all distributions follow the power-exponential law controlled by an exponent γ and a shift parameter u0 and examine how these parameters depend on the porosity. We find that γ has a universal value 1 /2 at the percolation threshold and grows with the porosity, but never exceeds 2.

  1. Distributed control of reactive power flow in a radial distribution circuit with high photovoltaic penetration

    SciTech Connect

    Chertkov, Michael; Turitsyn, Konstantin; Backhaus, Scott; Sule, Petr

    2009-01-01

    We show how distributed control of reactive power can serve to regulate voltage and minimize resistive losses in a distribution circuit that includes a significant level of photovoltaic (PV) generation. To demonstrate the technique, we consider a radial distribution circuit with a single branch consisting of sequentially-arranged residential-scale loads that consume both real and reactive power. In parallel, some loads also have PV generation capability. We postulate that the inverters associated with each PV system are also capable of limited reactive power generation or consumption, and we seek to find the optimal dispatch of each inverter's reactive power to both maintain the voltage within an acceptable range and minimize the resistive losses over the entire circuit. We assume the complex impedance of the distribution circuit links and the instantaneous load and PV generation at each load are known. We compare the results of the optimal dispatch with a suboptimal local scheme that does not require any communication. On our model distribution circuit, we illustrate the feasibility of high levels of PV penetration and a significant (20% or higher) reduction in losses.

  2. Distribution of organic anion transporters NaDC3 and OAT1-3 along the human nephron.

    PubMed

    Breljak, Davorka; Ljubojević, Marija; Hagos, Yohannes; Micek, Vedran; Balen Eror, Daniela; Vrhovac Madunić, Ivana; Brzica, Hrvoje; Karaica, Dean; Radović, Nikola; Kraus, Ognjen; Anzai, Naohiko; Koepsell, Hermann; Burckhardt, Gerhard; Burckhardt, Birgitta C; Sabolić, Ivan

    2016-07-01

    The initial step in renal secretion of organic anions (OAs) is mediated by transporters in the basolateral membrane (BLM). Contributors to this process are primary active Na(+)-K(+)-ATPase (EC 3.6.3.9), secondary active Na(+)-dicarboxylate cotransporter 3 (NaDC3/SLC13A3), and tertiary active OA transporters (OATs) OAT1/SLC22A6, OAT2/SLC22A7, and OAT3/SLC22A8. In human kidneys, we analyzed the localization of these transporters by immunochemical methods in tissue cryosections and isolated membranes. The specificity of antibodies was validated with human embryonic kidney-293 cells stably transfected with functional OATs. Na(+)-K(+)-ATPase was immunolocalized to the BLM along the entire human nephron. NaDC3-related immunostaining was detected in the BLM of proximal tubules and in the BLM and/or luminal membrane of principal cells in connecting segments and collecting ducts. The thin and thick ascending limbs, macula densa, and distal tubules exhibited no reactivity with the anti-NaDC3 antibody. OAT1-OAT3-related immunostaining in human kidneys was detected only in the BLM of cortical proximal tubules; all three OATs were stained more intensely in S1/S2 segments compared with S3 segment in medullary rays, whereas the S3 segment in the outer stripe remained unstained. Expression of NaDC3, OAT1, OAT2, and OAT3 proteins exhibited considerable interindividual variability in both male and female kidneys, and sex differences in their expression could not be detected. Our experiments provide a side-by-side comparison of basolateral transporters cooperating in renal OA secretion in the human kidney. PMID:27053689

  3. Power system distributed oscilation detection based on Synchrophasor data

    NASA Astrophysics Data System (ADS)

    Ning, Jiawei

    Along with increasing demand for electricity, integration of renewable energy and deregulation of power market, power industry is facing unprecedented challenges nowadays. Within the last couple of decades, several serious blackouts have been taking place in United States. As an effective approach to prevent that, power system small signal stability monitoring has been drawing more interests and attentions from researchers. With wide-spread implementation of Synchrophasors around the world in the last decade, power systems real-time online monitoring becomes much more feasible. Comparing with planning study analysis, real-time online monitoring would benefit control room operators immediately and directly. Among all online monitoring methods, Oscillation Modal Analysis (OMA), a modal identification method based on routine measurement data where the input is unmeasured ambient excitation, is a great tool to evaluate and monitor power system small signal stability. Indeed, high sampling Synchrophasor data around power system is fitted perfectly as inputs to OMA. Existing methods in OMA for power systems are all based on centralized algorithms applying at control centers only; however, with rapid growing number of online Synchrophasors the computation burden at control centers is and will be continually exponentially expanded. The increasing computation time at control center compromises the real-time feature of online monitoring. The communication efforts between substation and control center will also be out of reach. Meanwhile, it is difficult or even impossible for centralized algorithms to detect some poorly damped local modes. In order to avert previous shortcomings of centralized OMA methods and embrace the new changes in the power systems, two new distributed oscillation detection methods with two new decentralized structures are presented in this dissertation. Since the new schemes brought substations into the big oscillation detection picture, the proposed

  4. Auxiliary resonant DC tank converter

    DOEpatents

    Peng, Fang Z.

    2000-01-01

    An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

  5. Triple voltage dc-to-dc converter and method

    SciTech Connect

    Su, Gui-Jia

    2008-08-05

    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  6. Pseudodynamic planning for expansion of power distribution sytems

    SciTech Connect

    Ramirez-Rosado, I.J. ); Gonen, T. )

    1991-02-01

    This paper presents basic and extended planning models, based on a pseudodynamic methodology, to solve the global expansion problem (sizing, locating, and timing) of distribution substations and feeders throughout the planning time period. The objective functions, that represent the expansion costs, are minimized by successive concatenated optimizations subject to the Kirchhoff's current law, power capacity limits and logical constraints, in the basic model. It also presents an extended model that is obtained by including the voltage drop constraints in the basic model.

  7. A Single-Phase Current Source Solar Inverter with Constant Instantaneous Power, Improved Reliability, and Reduced-Size DC-Link Filter

    NASA Astrophysics Data System (ADS)

    Bush, Craig R.

    This dissertation presents a novel current source converter topology that is primarily intended for single-phase photovoltaic (PV) applications. In comparison with the existing PV inverter technology, the salient features of the proposed topology are: a) the low frequency (double of line frequency) ripple that is common to single-phase inverters is greatly reduced; b) the absence of low frequency ripple enables significantly reduced size pass components to achieve necessary DC-link stiffness and c) improved maximum power point tracking (MPPT) performance is readily achieved due to the tightened current ripple even with reduced-size passive components. The proposed topology does not utilize any electrolytic capacitors. Instead an inductor is used as the DC-link filter and reliable AC film capacitors are utilized for the filter and auxiliary capacitor. The proposed topology has a life expectancy on par with PV panels. The proposed modulation technique can be used for any current source inverter where an unbalanced three-phase operation is desires such as active filters and power controllers. The proposed topology is ready for the next phase of microgrid and power system controllers in that it accepts reactive power commands. This work presents the proposed topology and its working principle supported by with numerical verifications and hardware results. Conclusions and future work are also presented.

  8. Assessment of distributed solar power systems: Issues and impacts

    NASA Astrophysics Data System (ADS)

    Moyle, R. A.; Chernoff, H.; Schweizer, T. C.; Patton, J. B.

    1982-11-01

    The installation of distributed solar-power systems presents electric utilities with a host of questions. Some of the technical and economic impacts of these systems are discussed. Among the technical interconnect issues are isolated operation, power quality, line safety, and metering options. Economic issues include user purchase criteria, structures and installation costs, marketing and product distribution costs, and interconnect costs. An interactive computer program that allows easy calculation of allowable system prices and allowable generation-equipment prices was developed as part of this project. It is concluded that the technical problems raised by distributed solar systems are surmountable, but their resolution may be costly. The stringent purchase criteria likely to be imposed by many potential system users and the economies of large-scale systems make small systems (less than 10 to 20 kW) less attractive than larger systems. Utilities that consider life-cycle costs in making investment decisions and third-party investors who have tax and financial advantages are likely to place the highest value on solar-power systems.

  9. Distributed Solar Photovoltaic Power Production - Technology and Benefits

    SciTech Connect

    Matos, Al; Stuby, Rick

    2011-11-02

    As part of its nationally recognized Solar 4 All program, PSE&G has partnered with Petra Solar to deploy the world’s first and largest pole attached solar project. The project, based on Petra Solar’s distributed Smart Solar solution, will create a 40 megawatt solar “virtual power plant.” In deployment as 200,000 individual grid-connected solar power producers on utility poles in PSE&G territory, Petra Solar SunWave® solutions leverage Smart Grid communications and high-tech panel-level inverters to implement a robust system with many technical benefits over traditional solar photovoltaic solutions. The program overview, deployment model, smart grid communications and enabling inverter technology and safety features will be presented, as well the future challenges of, and solutions for, solar power intermittency as photovoltaic penetration on the electric grid increases.

  10. Power Management and Distribution (PMAD) Model Development: Final Report

    NASA Technical Reports Server (NTRS)

    Metcalf, Kenneth J.

    2011-01-01

    Power management and distribution (PMAD) models were developed in the early 1990's to model candidate architectures for various Space Exploration Initiative (SEI) missions. They were used to generate "ballpark" component mass estimates to support conceptual PMAD system design studies. The initial set of models was provided to NASA Lewis Research Center (since renamed Glenn Research Center) in 1992. They were developed to estimate the characteristics of power conditioning components predicted to be available in the 2005 timeframe. Early 90's component and device designs and material technologies were projected forward to the 2005 timeframe, and algorithms reflecting those design and material improvements were incorporated into the models to generate mass, volume, and efficiency estimates for circa 2005 components. The models are about ten years old now and NASA GRC requested a review of them to determine if they should be updated to bring them into agreement with current performance projections or to incorporate unforeseen design or technology advances. This report documents the results of this review and the updated power conditioning models and new transmission line models generated to estimate post 2005 PMAD system masses and sizes. This effort continues the expansion and enhancement of a library of PMAD models developed to allow system designers to assess future power system architectures and distribution techniques quickly and consistently.

  11. Klystron Cluster Scheme for ILC High Power RF Distribution

    SciTech Connect

    Nantista, Christopher; Adolphsen, Chris; /SLAC

    2009-07-06

    We present a concept for powering the main linacs of the International Linear Collider (ILC) by delivering high power RF from the surface via overmoded, low-loss waveguides at widely spaced intervals. The baseline design employs a two-tunnel layout, with klystrons and modulators evenly distributed along a service tunnel running parallel to the accelerator tunnel. This new idea eliminates the need for the service tunnel. It also brings most of the warm heat load to the surface, dramatically reducing the tunnel water cooling and HVAC requirements. In the envisioned configuration, groups of 70 klystrons and modulators are clustered in surface buildings every 2.5 km. Their outputs are combined into two half-meter diameter circular TE{sub 01} mode evacuated waveguides. These are directed via special bends through a deep shaft and along the tunnel, one upstream and one downstream. Each feeds approximately 1.25 km of linac with power tapped off in 10 MW portions at 38 m intervals. The power is extracted through a novel coaxial tap-off (CTO), after which the local distribution is as it would be from a klystron. The tap-off design is also employed in reverse for the initial combining.

  12. Early Oscillation Detection Technique for Hybrid DC/DC Converters

    NASA Technical Reports Server (NTRS)

    Wang, Bright L.

    2011-01-01

    Oscillation or instability is a situation that must be avoided for reliable hybrid DC/DC converters. A real-time electronics measurement technique was developed to detect catastrophic oscillations at early stages for hybrid DC/DC converters. It is capable of identifying low-level oscillation and determining the degree of the oscillation at a unique frequency for every individual model of the converters without disturbing their normal operations. This technique is specially developed for space-used hybrid DC/DC converters, but it is also suitable for most of commercial and military switching-mode power supplies. This is a weak-electronic-signal detection technique to detect hybrid DC/DC converter oscillation presented as a specific noise signal at power input pins. It is based on principles of feedback control loop oscillation and RF signal modulations, and is realized by using signal power spectral analysis. On the power spectrum, a channel power amplitude at characteristic frequency (CPcf) and a channel power amplitude at switching frequency (CPsw) are chosen as oscillation level indicators. If the converter is stable, the CPcf is a very small pulse and the CPsw is a larger, clear, single pulse. At early stage of oscillation, the CPcf increases to a certain level and the CPsw shows a small pair of sideband pulses around it. If the converter oscillates, the CPcf reaches to a higher level and the CPsw shows more high-level sideband pulses. A comprehensive stability index (CSI) is adopted as a quantitative measure to accurately assign a degree of stability to a specific DC/DC converter. The CSI is a ratio of normal and abnormal power spectral density, and can be calculated using specified and measured CPcf and CPsw data. The novel and unique feature of this technique is the use of power channel amplitudes at characteristic frequency and switching frequency to evaluate stability and identify oscillations at an early stage without interfering with a DC/DC converter s

  13. Design of Instantaneous High Power Supply System with power distribution management for portable military devices

    NASA Astrophysics Data System (ADS)

    Kwak, Kiho; Kwak, Dongmin; Yoon, Joohong

    2015-08-01

    A design of an Instantaneous High Power Supply System (IHPSS) with a power distribution management (PDM) for portable military devices is newly addressed. The system includes a power board and a hybrid battery that can not only supply instantaneous high power but also maintain stable operation at critical low temperature (-30 °C). The power leakage and battery overcharge are effectively prevented by the optimal PDM. The performance of the proposed system under the required pulse loads and the operating conditions of a Korean Advanced Combat Rifle employed in the battlefield is modeled with simulations and verified experimentally. The system with the IHPSS charged the fuse setter with 1.7 times higher voltage (8.6 V) than the one without (5.4 V) under the pulse discharging rate (1 A at 0.5 duty, 1 ms) for 500 ms.

  14. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    David Deangelis; Rich Depuy; Debashis Dey; Georgia Karvountzi; Nguyen Minh; Max Peter; Faress Rahman; Pavel Sokolov; Deliang Yang

    2004-09-30

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the April to October 2004 reporting period in Task 2.3 (SOFC Scaleup for Hybrid and Fuel Cell Systems) under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL), entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. This study analyzes the performance and economics of power generation systems for central power generation application based on Solid Oxide Fuel Cell (SOFC) technology and fueled by natural gas. The main objective of this task is to develop credible scale up strategies for large solid oxide fuel cell-gas turbine systems. System concepts that integrate a SOFC with a gas turbine were developed and analyzed for plant sizes in excess of 20 MW. A 25 MW plant configuration was selected with projected system efficiency of over 65% and a factory cost of under $400/kW. The plant design is modular and can be scaled to both higher and lower plant power ratings. Technology gaps and required engineering development efforts were identified and evaluated.

  15. Enhanced power quality based single phase photovoltaic distributed generation system

    NASA Astrophysics Data System (ADS)

    Panda, Aurobinda; Pathak, M. K.; Srivastava, S. P.

    2016-08-01

    This article presents a novel control strategy for a 1-ϕ 2-level grid-tie photovoltaic (PV) inverter to enhance the power quality (PQ) of a PV distributed generation (PVDG) system. The objective is to obtain the maximum benefits from the grid-tie PV inverter by introducing current harmonics as well as reactive power compensation schemes in its control strategy, thereby controlling the PV inverter to achieve multiple functions in the PVDG system such as: (1) active power flow control between the PV inverter and the grid, (2) reactive power compensation, and (3) grid current harmonics compensation. A PQ enhancement controller (PQEC) has been designed to achieve the aforementioned objectives. The issue of underutilisation of the PV inverter in nighttime has also been addressed in this article and for the optimal use of the system; the PV inverter is used as a shunt active power filter in nighttime. A prototype model of the proposed system is developed in the laboratory, to validate the effectiveness of the control scheme, and is tested with the help of the dSPACE DS1104 platform.

  16. Study on frequency characteristics of a small-scale wind power system with a d.c. generator

    NASA Astrophysics Data System (ADS)

    Suzuki, T.; Okitsu, H.; Kawahito, T.

    The frequency characteristics of a small dc windpowered generator are modeled in terms of a transfer function for the shaft speed and output variation due to changes in the wind speed. The perturbation method is employed for the development of the transfer functions, which are approximated as a form of a first order lag element. It is found that the gain constant increases proportionally to the load resistance. The results are compared to tests with a two-blade horizontal axis dc wind turbine, and good agreement is found. Extension of the method to predicting optimal working points for large wind turbines, wind energy systems with battery storage, and wind turbines using alternators is indicated.

  17. Observer-based higher order sliding mode control of power factor in three-phase AC/DC converter for hybrid electric vehicle applications

    NASA Astrophysics Data System (ADS)

    Liu, Jianxing; Laghrouche, Salah; Wack, Maxime

    2014-06-01

    In this paper, a full-bridge boost power converter topology is studied for power factor control, using output higher order sliding mode control. The AC/DC converters are used for charging the battery and super-capacitor in hybrid electric vehicles from the utility. The proposed control forces the input currents to track the desired values, which can control the output voltage while keeping the power factor close to one. Super-twisting sliding mode observer is employed to estimate the input currents and load resistance only from the measurement of output voltage. Lyapunov analysis shows the asymptotic convergence of the closed-loop system to zero. Multi-rate simulation illustrates the effectiveness and robustness of the proposed controller in the presence of measurement noise.

  18. Closed loop performance of a brushless dc motor powered electromechanical actuator for flight control applications. [computerized simulation for Shuttle Orbiter applications

    NASA Technical Reports Server (NTRS)

    Demerdash, N. A.; Nehl, T. W.

    1980-01-01

    A comprehensive digital model for the analysis and possible optimization of the closed loop dynamic (instantaneous) performance of a power conditioner fed, brushless dc motor powered, electromechanical actuator system (EMA) is presented. This model was developed for the simulation of the dynamic performance of an actual prototype EMA built for NASA-JSC as a possible alternative to hydraulic actuators for consideration in Space Shuttle Orbiter applications. Excellent correlation was achieved between numerical model simulation and experimental test results obtained from the actual hardware. These results include: various current and voltage waveforms in the machine-power conditioner (MPC) unit, flap position as well as other control loop variables in response to step commands of change of flap position. These results with consequent conclusions are detailed in the paper.

  19. Radiation-Tolerant DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

    2012-01-01

    A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

  20. Multi-port power router and its impact on resilient power grid systems

    NASA Astrophysics Data System (ADS)

    Kado, Yuichi; Iwatsuki, Katsumi; Wada, Keiji

    2016-02-01

    We propose a Y-configuration power router as a unit cell to easily construct a power delivery system that can meet many types of user requirements. The Y-configuration power router controls the direction and magnitude of power flow among three ports regardless of DC and AC. We constructed a prototype three-way isolated DC/DC converter that is the core unit of the Y-configuration power router and tested the power flow control operation. Experimental results revealed that our methodology based on the governing equation was appropriate for the power flow control of the three-way DC/DC converter. In addition, the hexagonal distribution network composed of the power routers has the ability to easily interchange electric power between autonomous microgrid cells. We also explored the requirements for communication between energy routers to achieve dynamic adjustments of energy flow in a coordinated manner and its impact on resilient power grid systems.

  1. 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

  2. A Multi-Agent Design for Power Distribution Systems Automation

    NASA Astrophysics Data System (ADS)

    Ghorbani, M. Jawad

    A new Multi Agent System (MAS) design for fault location, isolation and restoration in power distribution systems is presented. In proposed approach, when there is a fault in the Power Distribution System (PDS), MAS quickly isolates the fault and restores the service to fault-free zones. Hierarchical coordination strategy is introduced to manage the agents which integrate the advantages of both centralized and decentralized coordination strategies. In this framework, Zone Agent (ZA) locate and isolate the fault based on the locally available information and assist the Feeder Agent (FA) for reconfiguration and restoration. FA can solve the restoration problem using the existing algorithms for the 0-1 Knapsack problem. A novel Q-learning mechanism is also introduced to support the FAs in decision making for restoration. Also a distributed MAS-Based Load Shedding (LS) technique has been used to supply as many of higher priority customers as possible, in case there is more demand than generation. The design is illustrated by the use of simulation case studies for fault location, isolation and restoration on West Virginia Super Circuit (WVSC) and hardware implementation for fault location and isolation in a laboratory platform. The results from the case studies indicate the performance of proposed MAS designs.

  3. Measurement of the temperature distribution inside the power cable using distributed temperature system

    NASA Astrophysics Data System (ADS)

    Jaros, Jakub; Liner, Andrej; Papes, Martin; Vasinek, Vladimir; Mach, Veleslav; Hruby, David; Kajnar, Tomas; Perecar, Frantisek

    2015-01-01

    Nowadays, the power cables are manufactured to fulfill the following condition - the highest allowable temperature of the cable during normal operation and the maximum allowable temperature at short circuit conditions cannot exceed the condition of the maximum allowable internal temperature. The distribution of the electric current through the conductor leads to the increase of the amplitude of electrons in the crystal lattice of the cables material. The consequence of this phenomenon is the increase of friction and the increase of collisions between particles inside the material, which causes the temperature increase of the carrying elements. The temperature increase is unwanted phenomena, because it is causing losses. In extreme cases, the long-term overload leads to the cable damaging or fire. This paper deals with the temperature distribution measurement inside the power cables using distributed temperature system. With cooperation with Kabex company, the tube containing optical fibers was installed into the center of power cables. These fibers, except telecommunications purposes, can be also used as sensors in measurements carrying out with distributed temperature system. These systems use the optical fiber as a sensor and allow the continual measurement of the temperature along the whole cable in real time with spatial resolution 1 m. DTS systems are successfully deployed in temperature measurement applications in industry areas yet. These areas include construction, drainage, hot water etc. Their advantages are low cost, resistance to electromagnetic radiation and the possibility of real time monitoring at the distance of 8 km. The location of the optical fiber in the center of the power cable allows the measurement of internal distribution of the temperature during overloading the cable. This measurement method can be also used for prediction of short-circuit and its exact location.

  4. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Faress Rahman; Nguyen Minh

    2004-01-04

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the July 2003 to December 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. Also, another activity included in this program focuses on the development of SOFC scale up strategies.

  5. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Nguyen Minh

    2004-07-04

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the January to June 2004 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. Also, another activity included in this program focuses on the development of SOFC scale up strategies.

  6. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Nguyen Minh; Faress Rahman

    2002-12-31

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the October 2002 to December 2002 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. The following activities have been carried out during this reporting period: {lg_bullet} Conceptual system design trade studies were performed {lg_bullet} Part-load performance analysis was conducted {lg_bullet} Primary system concept was down-selected {lg_bullet} Dynamic control model has been developed {lg_bullet} Preliminary heat exchanger designs were prepared {lg_bullet} Pressurized SOFC endurance testing was performed

  7. Tomographic determination of the power distribution in electron beams

    DOEpatents

    Teruya, A.T.; Elmer, J.W.

    1996-12-10

    A tomographic technique for determining the power distribution of an electron beam using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams is disclosed. A refractory metal disk with a number of radially extending slits is placed above a Faraday cup. The beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. Also, a single computer is used to generate the signals actuating the sweep, to acquire that data, and to do the reconstruction, thus reducing the time and equipment necessary to complete the process. 4 figs.

  8. DC arc weld starter

    DOEpatents

    Campiotti, Richard H.; Hopwood, James E.

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  9. Measurement of deposition rate and ion energy distribution in a pulsed dc magnetron sputtering system using a retarding field analyzer with embedded quartz crystal microbalance.

    PubMed

    Sharma, Shailesh; Gahan, David; Scullin, Paul; Doyle, James; Lennon, Jj; Vijayaraghavan, Rajani K; Daniels, Stephen; Hopkins, M B

    2016-04-01

    A compact retarding field analyzer with embedded quartz crystal microbalance has been developed to measure deposition rate, ionized flux fraction, and ion energy distribution arriving at the substrate location. The sensor can be placed on grounded, electrically floating, or radio frequency (rf) biased electrodes. A calibration method is presented to compensate for temperature effects in the quartz crystal. The metal deposition rate, metal ionization fraction, and energy distribution of the ions arriving at the substrate location are investigated in an asymmetric bipolar pulsed dc magnetron sputtering reactor under grounded, floating, and rf biased conditions. The diagnostic presented in this research work does not suffer from complications caused by water cooling arrangements to maintain constant temperature and is an attractive technique for characterizing a thin film deposition system.

  10. Measurement of deposition rate and ion energy distribution in a pulsed dc magnetron sputtering system using a retarding field analyzer with embedded quartz crystal microbalance

    NASA Astrophysics Data System (ADS)

    Sharma, Shailesh; Gahan, David; Scullin, Paul; Doyle, James; Lennon, Jj; Vijayaraghavan, Rajani K.; Daniels, Stephen; Hopkins, M. B.

    2016-04-01

    A compact retarding field analyzer with embedded quartz crystal microbalance has been developed to measure deposition rate, ionized flux fraction, and ion energy distribution arriving at the substrate location. The sensor can be placed on grounded, electrically floating, or radio frequency (rf) biased electrodes. A calibration method is presented to compensate for temperature effects in the quartz crystal. The metal deposition rate, metal ionization fraction, and energy distribution of the ions arriving at the substrate location are investigated in an asymmetric bipolar pulsed dc magnetron sputtering reactor under grounded, floating, and rf biased conditions. The diagnostic presented in this research work does not suffer from complications caused by water cooling arrangements to maintain constant temperature and is an attractive technique for characterizing a thin film deposition system.

  11. Mesoscopic electronics beyond DC transport

    NASA Astrophysics Data System (ADS)

    di Carlo, Leonardo

    Since the inception of mesoscopic electronics in the 1980's, direct current (dc) measurements have underpinned experiments in quantum transport. Novel techniques complementing dc transport are becoming paramount to new developments in mesoscopic electronics, particularly as the road is paved toward quantum information processing. This thesis describes seven experiments on GaAs/AlGaAs and graphene nanostructures unified by experimental techniques going beyond traditional dc transport. Firstly, dc current induced by microwave radiation applied to an open chaotic quantum dot is investigated. Asymmetry of mesoscopic fluctuations of induced current in perpendicular magnetic field is established as a tool for separating the quantum photovoltaic effect from classical rectification. A differential charge sensing technique is next developed using integrated quantum point contacts to resolve the spatial distribution of charge inside a double quantum clot. An accurate method for determining interdot tunnel coupling and electron temperature using charge sensing is demonstrated. A two-channel system for detecting current noise in mesoscopic conductors is developed, enabling four experiments where shot noise probes transmission properties not available in dc transport and Johnson noise serves as an electron thermometer. Suppressed shot noise is observed in quantum point contacts at zero parallel magnetic field, associated with the 0.7 structure in conductance. This suppression evolves with increasing field into the shot-noise signature of spin-lifted mode degeneracy. Quantitative agreement is found with a phenomenological model for density-dependent mode splitting. Shot noise measurements of multi-lead quantum-dot structures in the Coulomb blockade regime distill the mechanisms by which Coulomb interaction and quantum indistinguishability correlate electron flow. Gate-controlled sign reversal of noise cross correlation in two capacitively-coupled dots is observed, and shown to

  12. Nonlinear analysis of a family of LC tuned inverters. [dc to square wave circuits for power conditioning

    NASA Technical Reports Server (NTRS)

    Lee, F. C. Y.; Wilson, T. G.

    1974-01-01

    A family of four dc-to-square-wave LC tuned inverters are analyzed using singular point. Limit cycles and waveshape characteristics are given for three modes of oscillation: quasi-harmonic, relaxation, and discontinuous. An inverter in which the avalanche breakdown of the transistor emitter-to-base junction occurs is discussed and the starting characteristics of this family of inverters are presented. The LC tuned inverters are shown to belong to a family of inverters with a common equivalent circuit consisting of only three 'series' elements: a five-segment piecewise-linear current-controlled resistor, linear inductor, and linear capacitor.

  13. High voltage DC switchgear development for multi-kW space power system: Aerospace technology development of three types of solid state power controllers for 200-1100VDC with current ratings of 25, 50, and 80 amperes with one type utilizing an electromechanical device

    NASA Technical Reports Server (NTRS)

    Billings, W. W.

    1981-01-01

    Three types of solid state power controllers (SSPC's) for high voltage, high power DC system applications were developed. The first type utilizes a SCR power switch. The second type employes an electromechanical power switch element with solid state commutation. The third type utilizes a transistor power switch. Significant accomplishments include high operating efficiencies, fault clearing, high/low temperature performance and vacuum operation.

  14. EMC and power quality standards for 20-kHz power distribution

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1987-01-01

    The Space Station Power Distribution System has been baselined as a sinusoidal single phase, 440 VRMS system. This system has certain unique characteristics directly affecting its application. In particular, existing systematic description and control documents were modified to reflect the high operating frequency. This paper will discuss amendments made on Mil STD 704 (Electrical Power Characteristics), and Mil STD 461-B (Electromagnetic Emission and Susceptibility Requirements for the Control of Electromagnetic Interference). In some cases these amendments reflect changes of several orders of magnitude. Implications and impacts of these changes are discussed.

  15. Single-phase power distribution system power flow and fault analysis

    NASA Technical Reports Server (NTRS)

    Halpin, S. M.; Grigsby, L. L.

    1992-01-01

    Alternative methods for power flow and fault analysis of single-phase distribution systems are presented. The algorithms for both power flow and fault analysis utilize a generalized approach to network modeling. The generalized admittance matrix, formed using elements of linear graph theory, is an accurate network model for all possible single-phase network configurations. Unlike the standard nodal admittance matrix formulation algorithms, the generalized approach uses generalized component models for the transmission line and transformer. The standard assumption of a common node voltage reference point is not required to construct the generalized admittance matrix. Therefore, truly accurate simulation results can be obtained for networks that cannot be modeled using traditional techniques.

  16. DC Breakdown Experiments

    SciTech Connect

    Calatroni, S.; Descoeudres, A.; Levinsen, Y.; Taborelli, M.; Wuensch, W.

    2009-01-22

    In the context of the CLIC (Compact Linear Collider) project investigations of DC breakdown in ultra high vacuum are carried out in parallel with high power RF tests. From the point of view of saturation breakdown field the best material tested so far is stainless steel, followed by titanium. Copper shows a four times weaker breakdown field than stainless steel. The results indicate clearly that the breakdown events are initiated by field emission current and that the breakdown field is limited by the cathode. In analogy to RF, the breakdown probability has been measured in DC and the data show similar behaviour as a function of electric field.

  17. Power Distribution Architecture for High Energy Physic Hostile Environment

    NASA Astrophysics Data System (ADS)

    Alderighi, M.; Citterio, M.; Latorre, S.; Riva, M.; Cova, P.; Delmonte, N.; Lanza, A.; Bernardoni, M.; Menozzi, R.; Costabeber, A.; Paccagnella, A.; Sichirollo, F.; Spiazzi, G.; Stellini, M.; Tenti, P.; Baccaro, S.; Iannuzzo, F.; Sanseverino, A.; Busatto, G.; de Luca, V.

    2012-08-01

    In the high luminosity phase of the Large Hadron Collider (LHC) the selection of the most suitable architecture able to supply the instrumentation of the experiments represents a critical task today. The power conversion units will have to supply low voltages and high currents to the loads with reduced transmission losses and, moreover, their design will have to face the critical demand of efficiency, robustness and limited size together with the need to operate in hostile environment. The paper discusses the most promising solutions in the power supply distribution networks which could be implemented in the upgraded detectors at the High Luminosity LHC collider. The proposed topologies have been selected by considering their tolerance to high background magnetic field and nuclear radiations as well as their limited electromagnetic noise emission. The analysis focuses on the description of the power supplies for noble liquid calorimeters, such as the Atlas LAr calorimeters, though several outcomes of this research can be applied to other detectors of the future LHC experiments.

  18. Fuel cycle comparison of distributed power generation technologies.

    SciTech Connect

    Elgowainy, A.; Wang, M. Q.; Energy Systems

    2008-12-08

    The fuel-cycle energy use and greenhouse gas (GHG) emissions associated with the application of fuel cells to distributed power generation were evaluated and compared with the combustion technologies of microturbines and internal combustion engines, as well as the various technologies associated with grid-electricity generation in the United States and California. The results were primarily impacted by the net electrical efficiency of the power generation technologies and the type of employed fuels. The energy use and GHG emissions associated with the electric power generation represented the majority of the total energy use of the fuel cycle and emissions for all generation pathways. Fuel cell technologies exhibited lower GHG emissions than those associated with the U.S. grid electricity and other combustion technologies. The higher-efficiency fuel cells, such as the solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC), exhibited lower energy requirements than those for combustion generators. The dependence of all natural-gas-based technologies on petroleum oil was lower than that of internal combustion engines using petroleum fuels. Most fuel cell technologies approaching or exceeding the DOE target efficiency of 40% offered significant reduction in energy use and GHG emissions.

  19. A pulsed DC gas flow hollow cathode

    NASA Astrophysics Data System (ADS)

    Paduraru, Cristian

    A new gas flow hollow cathode discharge source (GFHC) has been developed, characterized, and applied to thin film deposition by sputtering and low-temperature PECVD. Non-reactive and reactive sputtering processes were investigated using copper and aluminum targets, respectively. For the first time, pulsed DC power was applied to a GFHC in order to avoid arcing caused by electrode surface contamination, and to stabilize the discharge in general. The electrical characteristics of the source, the parameters of the remote plasma and its optical emission, were studied and compared to those of a DC powered GFHC. We determined the electrical characteristics of the plasma, including the temporal behavior of the current and voltage under various conditions of pressure and inert gas flow through the cathode. The transition from a glow discharge mode to the hollow cathode mode was studied in an effort to determine the operating range of the GFHC. A capacitive current was discovered at the beginning of the on-time. The properties of the remote plasma were investigated using averaged and time-resolved Langmuir probe and optical emission measurements. The distribution of the remote plasma density resembles the gas flow velocity distribution through the cathode. Plasma processes during off time (decaying plasma) and on-time (plasma reestablishment) were studied and compared to those in pulsed DC magnetron and high power inductively coupled glow discharges. The dependence of the deposition rate, resistivity and thickness distribution of copper films dependence on pulse parameters, power, inert gas flow through the cathode and pressure have been studied. The thin film thickness distribution is governed by the distribution of the gas flow velocity, which can be calculated using laminar flow gas dynamics. In a pulsed DC GFHC system, the inert gas flow through the cathode prevents the penetration of the reactive gas from the chamber into the cathode. A special reactive gas delivery

  20. Preparation of Power Distribution System for High Penetration of Renewable Energy Part I. Dynamic Voltage Restorer for Voltage Regulation Pat II. Distribution Circuit Modeling and Validation

    NASA Astrophysics Data System (ADS)

    Khoshkbar Sadigh, Arash

    Part I: Dynamic Voltage Restorer In the present power grids, voltage sags are recognized as a serious threat and a frequently occurring power-quality problem and have costly consequence such as sensitive loads tripping and production loss. Consequently, the demand for high power quality and voltage stability becomes a pressing issue. Dynamic voltage restorer (DVR), as a custom power device, is more effective and direct solutions for "restoring" the quality of voltage at its load-side terminals when the quality of voltage at its source-side terminals is disturbed. In the first part of this thesis, a DVR configuration with no need of bulky dc link capacitor or energy storage is proposed. This fact causes to reduce the size of the DVR and increase the reliability of the circuit. In addition, the proposed DVR topology is based on high-frequency isolation transformer resulting in the size reduction of transformer. The proposed DVR circuit, which is suitable for both low- and medium-voltage applications, is based on dc-ac converters connected in series to split the main dc link between the inputs of dc-ac converters. This feature makes it possible to use modular dc-ac converters and utilize low-voltage components in these converters whenever it is required to use DVR in medium-voltage application. The proposed configuration is tested under different conditions of load power factor and grid voltage harmonic. It has been shown that proposed DVR can compensate the voltage sag effectively and protect the sensitive loads. Following the proposition of the DVR topology, a fundamental voltage amplitude detection method which is applicable in both single/three-phase systems for DVR applications is proposed. The advantages of proposed method include application in distorted power grid with no need of any low-pass filter, precise and reliable detection, simple computation and implementation without using a phased locked loop and lookup table. The proposed method has been verified

  1. Study of the longitudinal distribution of power generated in a random distributed feedback Raman fibre laser with unidirectional pumping

    SciTech Connect

    Churkin, D V; El-Taher, A E; Vatnik, I D; Babin, Sergei A

    2012-09-30

    The longitudinal distribution of the Stokes-component power in a Raman fibre laser with a random distributed feedback and unidirectional pumping is measured. The fibre parameters (linear loss and Rayleigh backscattering coefficient) are calculated based on the distributions obtained. A numerical model is developed to describe the lasing power distribution. The simulation results are in good agreement with the experimental data. (optical fibres, lasers and amplifiers. properties and applications)

  2. Bi-Directional DC-DC Converter for PHEV Applications

    SciTech Connect

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  3. Impact of Increasing Distributed Wind Power and Wind Turbine Siting on Rural Distribution Feeder Voltage Profiles: Preprint

    SciTech Connect

    Allen, A.; Zhang, Y. C.; Hodge, B. M.

    2013-09-01

    Many favorable wind energy resources in North America are located in remote locations without direct access to the transmission grid. Building transmission lines to connect remotely-located wind power plants to large load centers has become a barrier to increasing wind power penetration in North America. By connecting utility-sized megawatt-scale wind turbines to the distribution system, wind power supplied to consumers could be increased greatly. However, the impact of including megawatt-scale wind turbines on distribution feeders needs to be studied. The work presented here examined the impact that siting and power output of megawatt-scale wind turbines have on distribution feeder voltage. This is the start of work to present a general guide to megawatt-scale wind turbine impact on the distribution feeder and finding the amount of wind power that can be added without adversely impacting the distribution feeder operation, reliability, and power quality.

  4. Distribution of dendritic cells expressing dendritic cell-specific ICAM-3-grabbing non-integrin (DC-SIGN, CD209): Morphological analysis using a novel Photoshop-aided multiple immunohistochemistry technique.

    PubMed

    Masuda, Akihiro; Nishikawa, Toshio

    2014-08-01

    The distribution of dendritic cells (DCs) expressing DC-specific ICAM-3-grabbing non-integrin (DC-SIGN, CD209) and the morphological interaction of DC-SIGN⁺ DCs with other cells, especially B cells, in tonsillar and other lymphoid tissues were investigated by multiple immunohistochemistry (IHC) using the graphics editing program Photoshop, which enabled staining with 4 or more antibodies in formalin-fixed paraffin sections. Images obtained by repetition of conventional IHC using diaminobenzidine color development in a tissue section were processed on Photoshop for multiple staining. DC-SIGN⁺ DCs were present in the area around the lymphoid follicles and formed a DC-SIGN⁺ DC-rich area, and these cells contacted not only T cells, fascin⁺ DCs, and blood vessels but also several subsets of B cells simultaneously, including naïve and memory B cells. DC-SIGN⁺ DCs may play an important role in the regulation of the immune response mediated by not only T cells but also B cells. The multiple IHC method introduced in the present study is a simple and useful method for analyzing details of complex structures. Because this method can be applied to routinely processed paraffin sections with conventional IHC with diaminobenzidine, it can be applied to a wide variety of archival specimens.

  5. Low Insertion HVDC Circuit Breaker: Magnetically Pulsed Hybrid Breaker for HVDC Power Distribution Protection

    SciTech Connect

    2012-01-09

    GENI Project: General Atomics is developing a direct current (DC) circuit breaker that could protect the grid from faults 100 times faster than its alternating current (AC) counterparts. Circuit breakers are critical elements in any electrical system. At the grid level, their main function is to isolate parts of the grid where a fault has occurred—such as a downed power line or a transformer explosion—from the rest of the system. DC circuit breakers must interrupt the system during a fault much faster than AC circuit breakers to prevent possible damage to cables, converters and other grid-level components. General Atomics’ high-voltage DC circuit breaker would react in less than 1/1,000th of a second to interrupt current during a fault, preventing potential hazards to people and equipment.

  6. Leadership in Mammalian Societies: Emergence, Distribution, Power, and Payoff.

    PubMed

    Smith, Jennifer E; Gavrilets, Sergey; Mulder, Monique Borgerhoff; Hooper, Paul L; El Mouden, Claire; Nettle, Daniel; Hauert, Christoph; Hill, Kim; Perry, Susan; Pusey, Anne E; van Vugt, Mark; Smith, Eric Alden

    2016-01-01

    Leadership is an active area of research in both the biological and social sciences. This review provides a transdisciplinary synthesis of biological and social-science views of leadership from an evolutionary perspective, and examines patterns of leadership in a set of small-scale human and non-human mammalian societies. We review empirical and theoretical work on leadership in four domains: movement, food acquisition, within-group conflict mediation, and between-group interactions. We categorize patterns of variation in leadership in five dimensions: distribution (across individuals), emergence (achieved versus inherited), power, relative payoff to leadership, and generality (across domains). We find that human leadership exhibits commonalities with and differences from the broader mammalian pattern, raising interesting theoretical and empirical issues. PMID:26552515

  7. SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION

    SciTech Connect

    Kurt Montgomery; Nguyen Minh

    2003-08-01

    This report summarizes the work performed by Honeywell during the October 2001 to December 2001 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. The conceptual and demonstration system designs were proposed and analyzed, and these systems have been modeled in Aspen Plus. Work has also started on the assembly of dynamic component models and the development of the top-level controls requirements for the system. SOFC stacks have been fabricated and performance mapping initiated.

  8. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Nguyen Minh

    2002-03-31

    This report summarizes the work performed by Honeywell during the January 2002 to March 2002 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. For this reporting period the following activities have been carried out: {lg_bullet} Conceptual system design trade studies were performed {lg_bullet} System-level performance model was created {lg_bullet} Dynamic control models are being developed {lg_bullet} Mechanical properties of candidate heat exchanger materials were investigated {lg_bullet} SOFC performance mapping as a function of flow rate and pressure was completed

  9. Leadership in Mammalian Societies: Emergence, Distribution, Power, and Payoff.

    PubMed

    Smith, Jennifer E; Gavrilets, Sergey; Mulder, Monique Borgerhoff; Hooper, Paul L; El Mouden, Claire; Nettle, Daniel; Hauert, Christoph; Hill, Kim; Perry, Susan; Pusey, Anne E; van Vugt, Mark; Smith, Eric Alden

    2016-01-01

    Leadership is an active area of research in both the biological and social sciences. This review provides a transdisciplinary synthesis of biological and social-science views of leadership from an evolutionary perspective, and examines patterns of leadership in a set of small-scale human and non-human mammalian societies. We review empirical and theoretical work on leadership in four domains: movement, food acquisition, within-group conflict mediation, and between-group interactions. We categorize patterns of variation in leadership in five dimensions: distribution (across individuals), emergence (achieved versus inherited), power, relative payoff to leadership, and generality (across domains). We find that human leadership exhibits commonalities with and differences from the broader mammalian pattern, raising interesting theoretical and empirical issues.

  10. C -parameter distribution at N3LL' including power corrections

    NASA Astrophysics Data System (ADS)

    Hoang, André H.; Kolodrubetz, Daniel W.; Mateu, Vicent; Stewart, Iain W.

    2015-05-01

    We compute the e+e- C -parameter distribution using the soft-collinear effective theory with a resummation to next-to-next-to-next-to-leading-log prime accuracy of the most singular partonic terms. This includes the known fixed-order QCD results up to O (αs3), a numerical determination of the two-loop nonlogarithmic term of the soft function, and all logarithmic terms in the jet and soft functions up to three loops. Our result holds for C in the peak, tail, and far tail regions. Additionally, we treat hadronization effects using a field theoretic nonperturbative soft function, with moments Ωn. To eliminate an O (ΛQCD) renormalon ambiguity in the soft function, we switch from the MS ¯ to a short distance "Rgap" scheme to define the leading power correction parameter Ω1. We show how to simultaneously account for running effects in Ω1 due to renormalon subtractions and hadron-mass effects, enabling power correction universality between C -parameter and thrust to be tested in our setup. We discuss in detail the impact of resummation and renormalon subtractions on the convergence. In the relevant fit region for αs(mZ) and Ω1, the perturbative uncertainty in our cross section is ≃ 2.5 % at Q =mZ.

  11. SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION

    SciTech Connect

    Faress Rahman; Nguyen Minh

    2003-07-01

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the January 2003 to June 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. This report summarizes the results obtained to date on: System performance analysis and model optimization; Reliability and cost model development; System control including dynamic model development; Heat exchanger material tests and life analysis; Pressurized SOFC evaluation; and Pre-baseline system definition for coal gasification fuel cell system concept.

  12. Fuel cell power plants in a distributed generator application

    SciTech Connect

    Smith, M.J.

    1996-12-31

    ONSI`s (a subsidiary of International Fuel Cells Corporation) world wide fleet of 200-kW PC25{trademark} phosphoric acid fuel cell power plants which began operation early in 1992 has shown excellent performance and reliability in over 1 million hours of operation. This experience has verified the clean, quiet, reliable operation of the PC25 and confirmed its application as a distributed generator. Continuing product development efforts have resulted in a one third reduction of weight and volume as well as improved installation and operating characteristics for the PC25 C model. Delivery of this unit began in 1995. International Fuel Cells (IFC) continues its efforts to improve product design and manufacturing processes. This progress has been sustained at a compounded rate of 10 percent per year since the late 1980`s. These improvements will permit further reductions in the initial cost of the power plant and place increased emphasis on market development as the pacing item in achieving business benefits from the PC25 fuel cell. Derivative product opportunities are evolving with maturation of the technologies in a commercial environment. The recent announcement of Praxair, Inc., and IFC introducing a non-cryogenic hydrogen supply system utilizing IFC`s steam reformer is an example. 11 figs.

  13. C -parameter distribution at N 3 LL ' including power corrections

    DOE PAGESBeta

    Hoang, André H.; Kolodrubetz, Daniel W.; Mateu, Vicent; Stewart, Iain W.

    2015-05-15

    We compute the e⁺e⁻ C-parameter distribution using the soft-collinear effective theory with a resummation to next-to-next-to-next-to-leading-log prime accuracy of the most singular partonic terms. This includes the known fixed-order QCD results up to O(α3s), a numerical determination of the two-loop nonlogarithmic term of the soft function, and all logarithmic terms in the jet and soft functions up to three loops. Our result holds for C in the peak, tail, and far tail regions. Additionally, we treat hadronization effects using a field theoretic nonperturbative soft function, with moments Ωn. To eliminate an O(ΛQCD) renormalon ambiguity in the soft function, we switchmore » from the MS¯ to a short distance “Rgap” scheme to define the leading power correction parameter Ω1. We show how to simultaneously account for running effects in Ω1 due to renormalon subtractions and hadron-mass effects, enabling power correction universality between C-parameter and thrust to be tested in our setup. We discuss in detail the impact of resummation and renormalon subtractions on the convergence. In the relevant fit region for αs(mZ) and Ω1, the perturbative uncertainty in our cross section is ≅ 2.5% at Q=mZ.« less

  14. Extending the Constant Power Speed Range of the Brushless DC Motor through Dual Mode Inverter Control -- Part I: Theory and Simulation

    SciTech Connect

    Lawler, J.S.

    2001-10-29

    An inverter topology and control scheme has been developed that can drive low-inductance, surface-mounted permanent magnet motors over the wide constant power speed range required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC) [1]. The DMIC can drive either the Permanent Magnet Synchronous Machine (PMSM) with sinusoidal back emf, or the brushless dc machine (BDCM) with trapezoidal emf in the motoring and regenerative braking modes. In this paper we concentrate on the BDCM under high-speed motoring conditions. Simulation results show that if all motor and inverter loss mechanisms are neglected, the constant power speed range of the DMIC is infinite. The simulation results are supported by closed form expressions for peak and rms motor current and average power derived from analytical solution to the differential equations governing the DMIC/BDCM drive for the lossless case. The analytical solution shows that the range of motor inductance that can be accommodated by the DMIC is more than an order of magnitude such that the DMIC is compatible with both low- and high-inductance BDCMs. Finally, method is given for integrating the classical hysteresis band current control, used for motor control below base speed, with the phase advance of DMIC that is applied above base speed. The power versus speed performance of the DMIC is then simulated across the entire speed range.

  15. Forback DC-to-DC converter

    NASA Astrophysics Data System (ADS)

    Lukemire, Alan T.

    1993-03-01

    A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

  16. Forback DC-to-DC converter

    NASA Astrophysics Data System (ADS)

    Lukemire, Alan T.

    1995-05-01

    A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

  17. Forback DC-to-DC converter

    NASA Technical Reports Server (NTRS)

    Lukemire, Alan T. (Inventor)

    1995-01-01

    A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.

  18. Performance and Economic Analysis of Distributed Power Electronics in Photovoltaic Systems

    SciTech Connect

    Deline, C.; Marion, B.; Granata, J.; Gonzalez, S.

    2011-01-01

    Distributed electronics like micro-inverters and DC-DC converters can help recover mismatch and shading losses in photovoltaic (PV) systems. Under partially shaded conditions, the use of distributed electronics can recover between 15-40% of annual performance loss or more, depending on the system configuration and type of device used. Additional value-added features may also increase the benefit of using per-panel distributed electronics, including increased safety, reduced system design constraints and added monitoring and diagnostics. The economics of these devices will also become more favorable as production volume increases, and integration within the solar panel?s junction box reduces part count and installation time. Some potential liabilities of per-panel devices include increased PV system cost, additional points of failure, and an insertion loss that may or may not offset performance gains under particular mismatch conditions.

  19. Preliminary analysis of Block Island Power Company's use of clean distributed resources to provide power to its customers

    SciTech Connect

    Hoff, T.E.

    2000-01-25

    This report is an analysis of the potential for Block Island Power Company (BIPCO) to use renewable energy and clean distributed resources to supply power to its customers. The preliminary conclusion of this work is that a system composed of clean distributed resources has the potential to be a technically and economically feasible alternative for BIPCO.

  20. Validating MCNP for LEU Fuel Design via Power Distribution Comparisons

    SciTech Connect

    Primm, Trent; Maldonado, G Ivan; Chandler, David

    2008-11-01

    The mission of the Reduced Enrichment for Research and Test Reactors (RERTR) Program is to minimize and, to the extent possible, eliminate the use of highly enriched uranium (HEU) in civilian nuclear applications by working to convert research and test reactors, as well as radioisotope production processes, to low enriched uranium (LEU) fuel and targets. Oak Ridge National Lab (ORNL) is reviewing the design bases and key operating criteria including fuel operating parameters, enrichment-related safety analyses, fuel performance, and fuel fabrication in regard to converting the fuel of the High Flux Isotope Reactor (HFIR) from HEU to LEU. The purpose of this study is to validate Monte Carlo methods currently in use for conversion analyses. The methods have been validated for the prediction of flux values in the reactor target, reflector, and beam tubes, but this study focuses on the prediction of the power density profile in the core. A current 3-D Monte Carlo N-Particle (MCNP) model was modified to replicate the HFIR Critical Experiment 3 (HFIRCE-3) core of 1965. In this experiment, the power profile was determined by counting the gamma activity at selected locations in the core. Foils (chunks of fuel meat and clad) were punched out of the fuel elements in HFIRCE-3 following irradiation and experimental relative power densities were obtained by measuring the activity of these foils and comparing each foil s activity to the activity of a normalizing foil. The current work consisted of calculating corresponding activities by inserting volume tallies into the modified MCNP model to represent the punchings. The average fission density was calculated for each foil location and then normalized to the normalizing foil. Power distributions were obtained for the clean core (no poison in moderator and symmetrical rod position at 17.5 inches) and fully poisoned-moderator (1.35 g B/liter in moderator and rods fully withdrawn) conditions. The observed deviations between the

  1. Aging Management Guideline for commercial nuclear power plants: Power and distribution transformers

    SciTech Connect

    Toman, G.; Gazdzinski, R.

    1994-05-01

    This Aging Management Guideline (AMG) provides recommended methods for effective detection and mitigation of age-related degradation mechanisms in power and distribution transformers important to license renewal in commercial nuclear power plants. The intent of this AMG to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR Part 54. This AMG is presented in a manner which allows personnel responsible for performance analysis and maintenance to compare their plant-specific aging mechanisms (expected or already experienced) and aging management program activities to the more generic results and recommendations presented herein.

  2. RISK D/C

    NASA Technical Reports Server (NTRS)

    Dias, W. C.

    1994-01-01

    RISK D/C is a prototype program which attempts to do program risk modeling for the Space Exploration Initiative (SEI) architectures proposed in the Synthesis Group Report. Risk assessment is made with respect to risk events, their probabilities, and the severities of potential results. The program allows risk mitigation strategies to be proposed for an exploration program architecture and to be ranked with respect to their effectiveness. RISK D/C allows for the fact that risk assessment in early planning phases is subjective. Although specific to the SEI in its present form, RISK D/C can be used as a framework for developing a risk assessment program for other specific uses. RISK D/C is organized into files, or stacks, of information, including the architecture, the hazard, and the risk event stacks. Although predefined, all stacks can be upgraded by a user. The architecture stack contains information concerning the general program alternatives, which are subsequently broken down into waypoints, missions, and mission phases. The hazard stack includes any background condition which could result in a risk event. A risk event is anything unfavorable that could happen during the course of a specific point within an architecture, and the risk event stack provides the probabilities, consequences, severities, and any mitigation strategies which could be used to reduce the risk of the event, and how much the risk is reduced. RISK D/C was developed for Macintosh series computers. It requires HyperCard 2.0 or later, as well as 2Mb of RAM and System 6.0.8 or later. A Macintosh II series computer is recommended due to speed concerns. The standard distribution medium for this package is one 3.5 inch 800K Macintosh format diskette. RISK D/C was developed in 1991 and is a copyrighted work with all copyright vested in NASA. Macintosh and HyperCard are trademarks of Apple Computer, Inc.

  3. New approaches to provide ride-through for critical loads in electric power distribution systems

    NASA Astrophysics Data System (ADS)

    Montero-Hernandez, Oscar C.

    2001-07-01

    The extensive use of electronic circuits has enabled modernization, automation, miniaturization, high quality, low cost, and other achievements regarding electric loads in the last decades. However, modern electronic circuits and systems are extremely sensitive to disturbances from the electric power supply. In fact, the rate at which these disturbances happen is considerable as has been documented in recent years. In response to the power quality concerns presented previously, this dissertation is proposing new approaches to provide ride-through for critical loads during voltage disturbances with emphasis on voltage sags. In this dissertation, a new approach based on an AC-DC-AC system is proposed to provide ride-through for critical loads connected in buildings and/or an industrial system. In this approach, a three-phase IGBT inverter with a built in Dc-link voltage regulator is suitably controlled along with static by-pass switches to provide continuous power to critical loads. During a disturbance, the input utility source is disconnected and the power from the inverter is connected to the load. The remaining voltage in the AC supply is converted to DC and compensated before being applied to the inverter and the load. After detecting normal utility conditions, power from the utility is restored to the critical load. In order to achieve an extended ride-through capability a second approach is introduced. In this case, the Dc-link voltage regulator is performed by a DC-DC Buck-Boost converter. This new approach has the capability to mitigate voltage variations below and above the nominal value. In the third approach presented in this dissertation, a three-phase AC to AC boost converter is investigated. This converter provides a boosting action for the utility input voltages, right before they are applied to the load. The proposed Pulse Width Modulation (PWM) control strategy ensures independent control of each phase and compensates for both single-phase or poly

  4. Influence of substrate on the distribution of the Hawaiian Silversword ( Argyroxiphium sandwicense DC.) in Haleakala (Maui, HI)

    NASA Astrophysics Data System (ADS)

    Pérez, Francisco L.

    2003-09-01

    The spatial patterns of the Hawaiian silversword ( Argyroxiphium sandwicense DC.) were studied in Haleakala (Maui, HI). The silversword is a "giant" rosette plant nearly brought to extinction by human impact and goat browsing during the 1920s, but stern protection has resulted in the resurgence of plant populations. Silversword regeneration is occurring vigorously in soils with surficial layers of volcaniclastic fragments. Ten sites with sizable silversword populations and the associated substrates were examined in Haleakala's crater between 2175 and 2755 m. At each site, the population structure of 100 plants was determined along wandering-quarter transects, which limit sampling bias. Substrates where rosettes were rooted and the size of the biggest stone fragments upslope and downslope from the plant's base were determined. Volcaniclastic substrates were examined with photographs along 12-m-long transverse transects. Fine-debris samples (gravel and pebbles) were analyzed by mechanical sifting of surficial fragments gathered from 15×15 cm miniplots. Volcaniclastic fragments in silversword areas have different sources. (i) Most were ejected during eruptions yielding pyroclastic materials (ash to blocks) that built cinder cones on Haleakala's crater. (ii) On steep slopes, weathering of (olivine alkali) basalt outcrops and subsequent mass wasting of rock fragments contributed a mantle of clasts to slopes below. (iii) On some cinder cones, welded spatter was produced during late eruptive stages; this coalesced into ruff-like agglutinate layers around crater rims, called Pohaku-o-Hanalei ("wreath of stones"). Agglutinate deposits weather gradually, supplying clasts that roll downhill and accumulate on cone flanks. (iv) On weathered aa lava flows, stone fragments and rocky crags abound along eroding lava-flow ridges, associated with vegetation; but the intervening troughs, covered with fine ash and cinder, remain bare. Silversword population structures indicate healthy

  5. Effect of trace elements vanadium and nickel on iron intermetallic phases formation and distribution in DC cast 5xxx series aluminum ingots

    NASA Astrophysics Data System (ADS)

    Li, Gaofeng

    AA5657 alloy is one of the important members of 5xxx-series alloys. It has application in many fields as packing, electricity, architectural, and printing. These applications require high quality surface finishing, and the alloy ingots require homogeneous microstructure. In the industry of DC (direct-chill) casting of 1xxx and 5xxx-series aluminium ingots, there exist different cooling rates from the casting surface to the ingot center. Thus, different Fe intermetallic phases such as AlmFe, Al6Fe, alpha-AlFeSi and Al3Fe can form preferentially in different positions of the ingot. The Fe intermetallic phase transition in DC casting ingot may cause microstructure inhomogeneities, which in turn cause the so called fir-tree zones (FTZs) in the ingots as well as streaks and bands on the Al sheets. Nowadays, with the increase of impurity in aluminium smelting raw materials (coke, alumina, etc.), the levels of trace elements present in the primary metal is gradually increasing. The impact of this increase on the aluminium transformation process and the final products is uncertain. Thus, there is a clear need to better understand these impacts, which will allow identifying ways to mitigate the negative impacts. The study presented in this thesis was performed on AA5657 alloys to study the effect of trace elements V and Ni on Fe intermetallic phases formation and distribution. A slice of AA1050 alloy ingot with visible FTZs was also studied to characterize the Fe intermetallic phases transition across the FTZs. A DC simulator was built in the lab, which can reproduce the solidification conditions in the sub-surface regions of industry ingots. The methods for the characterization of Fe intermetallic particles were developed in this research. AlmFe, Al6Fe, alpha-AlFeSi and alpha-Al3Fe intermetallic phases were successfully identified by using Deep-etching method, EDS and EBSD technique in combination. Quantitative analysis of the Fe intermetallic particles was carried out by

  6. Practical Design Guidelines of qZSI Based Step-Up DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Zakis, Janis; Vinnikov, Dmitri; Roasto, Indrek; Jalakas, Tanel

    2010-01-01

    This paper presents some design guidelines for a new voltage fed step-up DC/DC isolated converter. The most significant advantage of proposed converter is voltage buck-boost operation on single stage. The most promising application for proposed converter is in the field of distributed power generation e.g. fuel cells or photovoltaic. The most sensitive issues - such as power losses caused by high currents in the input side of converter and high transient overvoltages across the inverter bridge caused by stray inductances were discussed and solved. The proposals and recommendations to overcome these issues are given in the paper. The Selection and design guidelines of converter elements are proposed and explained. The prototype of proposed converter was built and experimentally tested. Some results are presented and evaluated.

  7. Modeling magnetic fields from a DC power cable buried beneath San Francisco Bay based on empirical measurements

    DOE PAGESBeta

    Kavet, Robert; Wyman, Megan T.; Klimley, A. Peter; Carretero, Luis

    2016-02-25

    Here, the Trans Bay Cable (TBC) is a ±200-kilovolt (kV), 400 MW 85-km long High Voltage Direct Current (DC) buried transmission line linking Pittsburg, CA with San Francisco, CA (SF) beneath the San Francisco Estuary. The TBC runs parallel to the migratory route of various marine species, including green sturgeon, Chinook salmon, and steelhead trout. In July and August 2014, an extensive series of magnetic field measurements were taken using a pair of submerged Geometrics magnetometers towed behind a survey vessel in four locations in the San Francisco estuary along profiles that cross the cable’s path; these included the Sanmore » Francisco-Oakland Bay Bridge (BB), the Richmond-San Rafael Bridge (RSR), the Benicia- Martinez Bridge (Ben) and an area in San Pablo Bay (SP) in which a bridge is not present. In this paper, we apply basic formulas that ideally describe the magnetic field from a DC cable summed vectorially with the background geomagnetic field (in the absence of other sources that would perturb the ambient field) to derive characteristics of the cable that are otherwise not immediately observable. Magnetic field profiles from measurements taken along 170 survey lines were inspected visually for evidence of a distinct pattern representing the presence of the cable. Many profiles were dominated by field distortions unrelated to the cable caused by bridge structures or other submerged objects, and the cable’s contribution to the field was not detectable. BB, with 40 of the survey lines, did not yield usable data for these reasons. The unrelated anomalies could be up to 100 times greater than those from the cable. In total, discernible magnetic field profiles measured from 76 survey lines were regressed against the equations, representing eight days of measurement. The modeled field anomalies due to the cable (the difference between the maximum and minimum field along the survey line at the cable crossing) were virtually identical to the measured

  8. Modeling Magnetic Fields from a DC Power Cable Buried Beneath San Francisco Bay Based on Empirical Measurements

    PubMed Central

    Kavet, Robert; Wyman, Megan T.; Klimley, A. Peter

    2016-01-01

    The Trans Bay Cable (TBC) is a ±200-kilovolt (kV), 400 MW 85-km long High Voltage Direct Current (DC) buried transmission line linking Pittsburg, CA with San Francisco, CA (SF) beneath the San Francisco Estuary. The TBC runs parallel to the migratory route of various marine species, including green sturgeon, Chinook salmon, and steelhead trout. In July and August 2014, an extensive series of magnetic field measurements were taken using a pair of submerged Geometrics magnetometers towed behind a survey vessel in four locations in the San Francisco estuary along profiles that cross the cable’s path; these included the San Francisco-Oakland Bay Bridge (BB), the Richmond-San Rafael Bridge (RSR), the Benicia-Martinez Bridge (Ben) and an area in San Pablo Bay (SP) in which a bridge is not present. In this paper, we apply basic formulas that ideally describe the magnetic field from a DC cable summed vectorially with the background geomagnetic field (in the absence of other sources that would perturb the ambient field) to derive characteristics of the cable that are otherwise not immediately observable. Magnetic field profiles from measurements taken along 170 survey lines were inspected visually for evidence of a distinct pattern representing the presence of the cable. Many profiles were dominated by field distortions unrelated to the cable caused by bridge structures or other submerged objects, and the cable’s contribution to the field was not detectable. BB, with 40 of the survey lines, did not yield usable data for these reasons. The unrelated anomalies could be up to 100 times greater than those from the cable. In total, discernible magnetic field profiles measured from 76 survey lines were regressed against the equations, representing eight days of measurement. The modeled field anomalies due to the cable (the difference between the maximum and minimum field along the survey line at the cable crossing) were virtually identical to the measured values. The

  9. Modeling Magnetic Fields from a DC Power Cable Buried Beneath San Francisco Bay Based on Empirical Measurements.

    PubMed

    Kavet, Robert; Wyman, Megan T; Klimley, A Peter

    2016-01-01

    The Trans Bay Cable (TBC) is a ±200-kilovolt (kV), 400 MW 85-km long High Voltage Direct Current (DC) buried transmission line linking Pittsburg, CA with San Francisco, CA (SF) beneath the San Francisco Estuary. The TBC runs parallel to the migratory route of various marine species, including green sturgeon, Chinook salmon, and steelhead trout. In July and August 2014, an extensive series of magnetic field measurements were taken using a pair of submerged Geometrics magnetometers towed behind a survey vessel in four locations in the San Francisco estuary along profiles that cross the cable's path; these included the San Francisco-Oakland Bay Bridge (BB), the Richmond-San Rafael Bridge (RSR), the Benicia-Martinez Bridge (Ben) and an area in San Pablo Bay (SP) in which a bridge is not present. In this paper, we apply basic formulas that ideally describe the magnetic field from a DC cable summed vectorially with the background geomagnetic field (in the absence of other sources that would perturb the ambient field) to derive characteristics of the cable that are otherwise not immediately observable. Magnetic field profiles from measurements taken along 170 survey lines were inspected visually for evidence of a distinct pattern representing the presence of the cable. Many profiles were dominated by field distortions unrelated to the cable caused by bridge structures or other submerged objects, and the cable's contribution to the field was not detectable. BB, with 40 of the survey lines, did not yield usable data for these reasons. The unrelated anomalies could be up to 100 times greater than those from the cable. In total, discernible magnetic field profiles measured from 76 survey lines were regressed against the equations, representing eight days of measurement. The modeled field anomalies due to the cable (the difference between the maximum and minimum field along the survey line at the cable crossing) were virtually identical to the measured values. The modeling

  10. Modeling Magnetic Fields from a DC Power Cable Buried Beneath San Francisco Bay Based on Empirical Measurements.

    PubMed

    Kavet, Robert; Wyman, Megan T; Klimley, A Peter

    2016-01-01

    The Trans Bay Cable (TBC) is a ±200-kilovolt (kV), 400 MW 85-km long High Voltage Direct Current (DC) buried transmission line linking Pittsburg, CA with San Francisco, CA (SF) beneath the San Francisco Estuary. The TBC runs parallel to the migratory route of various marine species, including green sturgeon, Chinook salmon, and steelhead trout. In July and August 2014, an extensive series of magnetic field measurements were taken using a pair of submerged Geometrics magnetometers towed behind a survey vessel in four locations in the San Francisco estuary along profiles that cross the cable's path; these included the San Francisco-Oakland Bay Bridge (BB), the Richmond-San Rafael Bridge (RSR), the Benicia-Martinez Bridge (Ben) and an area in San Pablo Bay (SP) in which a bridge is not present. In this paper, we apply basic formulas that ideally describe the magnetic field from a DC cable summed vectorially with the background geomagnetic field (in the absence of other sources that would perturb the ambient field) to derive characteristics of the cable that are otherwise not immediately observable. Magnetic field profiles from measurements taken along 170 survey lines were inspected visually for evidence of a distinct pattern representing the presence of the cable. Many profiles were dominated by field distortions unrelated to the cable caused by bridge structures or other submerged objects, and the cable's contribution to the field was not detectable. BB, with 40 of the survey lines, did not yield usable data for these reasons. The unrelated anomalies could be up to 100 times greater than those from the cable. In total, discernible magnetic field profiles measured from 76 survey lines were regressed against the equations, representing eight days of measurement. The modeled field anomalies due to the cable (the difference between the maximum and minimum field along the survey line at the cable crossing) were virtually identical to the measured values. The modeling

  11. Wind Power Forecasting Error Distributions over Multiple Timescales: Preprint

    SciTech Connect

    Hodge, B. M.; Milligan, M.

    2011-03-01

    In this paper, we examine the shape of the persistence model error distribution for ten different wind plants in the ERCOT system over multiple timescales. Comparisons are made between the experimental distribution shape and that of the normal distribution.

  12. The distribution of absorptive power dissipation in irradiated nanoparticulate system

    NASA Astrophysics Data System (ADS)

    Li, Jiayu; Yang, Jian; Gu, Xiaobing

    2016-10-01

    The knowledge of local radiant absorption is important to the nanostructure optimization, it is beneficial to the applications in energy harvesting, optical heating, photocatalysis, etc. In this paper, FDTD model is constructed for the distribution of absorptive power dissipation in irradiated nanoparticulate system. The theoretical model extended from Mie theory is used to examine the FDTD model, the parameters and conditions set for FDTD simulation are confirmed based on the comparison. Then, the influence of Ag nanoparticle on the absorptive properties of nearby TiO2 nanoparticle is investigated by FDTD simulation at the wavelength of 0.25 μm. It is indicated that suitable distance between TiO2 and Ag particles is beneficial to the spectral radiant absorption of TiO2 particle. Considering the agglomeration of nanoparticles and the oxidation at the TiO2-Ag interface, the Ag core coated with Al2O3 shell is suggested, and the simulated results indicated that the shell thickness and the Ag core size need to be optimized for enhancing the radiant absorption of TiO2 particle.

  13. Applying model-based diagnostics to space power distribution

    NASA Astrophysics Data System (ADS)

    Quinn, Todd M.; Schlegelmilch, Richard F.

    1994-03-01

    When engineers diagnose system failures, they often use models to confirm system operation. This concept has produced a class of advanced expert systems which perform model-based diagnosis. A model-based diagnostic expert system for a Space Station Freedom electrical power distribution testbed is currently being developed at the NASA Lewis Research Center. The objective of this expert system is to autonomously detect and isolate electrical fault conditions. Marple, a software package developed at TRW, provides a model-based environment utilizing constraint suspension. Originally, constraint suspension techniques were developed for digital systems. However, Marple provides the mechanisms for applying this approach to analog systems, such as the testbed, as well. The expert system was developed using Marple and Lucid Common Lisp running on Sun Sparc-2 workstation. The Marple modeling environment has proved to be a useful tool for investigating the various aspects of model-based diagnostics. This paper describes work completed to date and lessons learned while employing model-based diagnostics using constraint suspension within an analog system.

  14. Stability Testing and Analysis of a PMAD DC Test Bed for the Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Button, Robert M.; Brush, Andrew S.

    1992-01-01

    The Power Management and Distribution (PMAD) DC Test Bed at the NASA Lewis Research Center is introduced. Its usefulness to the Space Station Freedom Electrical Power (EPS) development and design are discussed in context of verifying system stability. Stability criteria developed by Middlebrook and Cuk are discussed as they apply to constant power DC to DC converters exhibiting negative input impedance at low frequencies. The utility-type Secondary Subsystem is presented and each component is described. The instrumentation used to measure input and output impedance under load is defined. Test results obtained from input and output impedance measurements of test bed components are presented. It is shown that the PMAD DC Test Bed Secondary Subsystem meets the Middlebrook stability criterion for certain loading conditions.

  15. Stability testing and analysis of a PMAD dc test bed for the Space Station Freedom

    NASA Astrophysics Data System (ADS)

    Button, Robert M.; Brush, Andrew S.

    The Power Management and Distribution (PMAD) dc Test Bed at the NASA Lewis Research Center is introduced. Its usefulness to the Space Station Freedom Electrical Power (EPS) development and design are discussed in context of verifying system stability. Stability criteria developed by Middlebrook and Cuk are discussed as they apply to constant power dc to dc converters exhibiting negative input impedance at low frequencies. The utility-type Secondary Subsystem is presented and each component is described. The instrumentation used to measure input and output impedance under load is defined. Test results obtained from input and output impedance measurements of test bed components are presented. It is shown that the PMAD dc Test Bed Secondary Subsystem meets the Middlebrook stability criterion for certain loading conditions.

  16. Stability testing and analysis of a PMAD DC test bed for the Space Station Freedom

    NASA Astrophysics Data System (ADS)

    Button, Robert M.; Brush, Andrew S.

    1992-08-01

    The Power Management and Distribution (PMAD) DC Test Bed at the NASA Lewis Research Center is introduced. Its usefulness to the Space Station Freedom Electrical Power (EPS) development and design are discussed in context of verifying system stability. Stability criteria developed by Middlebrook and Cuk are discussed as they apply to constant power DC to DC converters exhibiting negative input impedance at low frequencies. The utility-type Secondary Subsystem is presented and each component is described. The instrumentation used to measure input and output impedance under load is defined. Test results obtained from input and output impedance measurements of test bed components are presented. It is shown that the PMAD DC Test Bed Secondary Subsystem meets the Middlebrook stability criterion for certain loading conditions.

  17. The place of solar power: an economic analysis of concentrated and distributed solar power

    PubMed Central

    2012-01-01

    Background This paper examines the cost and benefits, both financial and environmental, of two leading forms of solar power generation, grid-tied photovoltaic cells and Dish Stirling Systems, using conventional carbon-based fuel as a benchmark. Methods First we define how these solar technologies will be implemented and why. Then we delineate a model city and its characteristics, which will be used to test the two methods of solar-powered electric distribution. Then we set the constraining assumptions for each technology, which serve as parameters for our calculations. Finally, we calculate the present value of the total cost of conventional energy needed to power our model city and use this as a benchmark when analyzing both solar models’ benefits and costs. Results The preeminent form of distributed electricity generation, grid-tied photovoltaic cells under net-metering, allow individual homeowners a degree of electric self-sufficiency while often turning a profit. However, substantial subsidies are required to make the investment sensible. Meanwhile, large dish Stirling engine installations have a significantly higher potential rate of return, but face a number of pragmatic limitations. Conclusions This paper concludes that both technologies are a sensible investment for consumers, but given that the dish Stirling consumer receives 6.37 dollars per watt while the home photovoltaic system consumer receives between 0.9 and 1.70 dollars per watt, the former appears to be a superior option. Despite the large investment, this paper deduces that it is far more feasible to get few strong investors to develop a solar farm of this magnitude, than to get 150,000 households to install photovoltaic arrays in their roofs. Potential implications of the solar farm construction include an environmental impact given the size of land require for this endeavour. However, the positive aspects, which include a large CO2 emission reduction aggregated over the lifespan of the farm

  18. Solar Power Satellite Microwave Power Transmission System Description Executive Summary

    NASA Technical Reports Server (NTRS)

    Woodcock, G. R.

    1980-01-01

    The history of the concept of microwave power beaming to Earth is reviewed with emphasis on transmission frequency selection. Constraints on the system power level results from (1) required rejection of waste heat resulting from inefficiencies in the cover conversion of dc electric power to microwave power; (2) the rf power intensity in the ionosphere; and (3) the effect of sidelobe level on aperture illumination factors. Transmitter arrangement, the power distribution system, attitude control, subarrays, waveguides, and alignment are discussed.

  19. Distributed solid state programmable thermostat/power controller

    NASA Technical Reports Server (NTRS)

    Alexander, Jane C. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    2008-01-01

    A self-contained power controller having a power driver switch, programmable controller, communication port, and environmental parameter measuring device coupled to a controllable device. The self-contained power controller needs only a single voltage source to power discrete devices, analog devices, and the controlled device. The programmable controller has a run mode which, when selected, upon the occurrence of a trigger event changes the state of a power driver switch and wherein the power driver switch is maintained by the programmable controller at the same state until the occurrence of a second event.

  20. Fault Analysis of Space Station DC Power Systems-Using Neural Network Adaptive Wavelets to Detect Faults

    NASA Technical Reports Server (NTRS)

    Momoh, James A.; Wang, Yanchun; Dolce, James L.

    1997-01-01

    This paper describes the application of neural network adaptive wavelets for fault diagnosis of space station power system. The method combines wavelet transform with neural network by incorporating daughter wavelets into weights. Therefore, the wavelet transform and neural network training procedure become one stage, which avoids the complex computation of wavelet parameters and makes the procedure more straightforward. The simulation results show that the proposed method is very efficient for the identification of fault locations.

  1. Baccharis trimera (Less.) DC as genotoxicity indicator of exposure to coal and emissions from a thermal power plant.

    PubMed

    Menezes, Ana Paula Simões; Da Silva, Juliana; Roloff, Joice; Reyes, Juliana; Debastiani, Rafaela; Dias, Johnny F; Rohr, Paula; de Barros Falcão Ferraz, Alexandre

    2013-10-01

    During coal combustion, hazardous elements are discharged that impair environmental quality. Plant cover is the first available surface for the atmospheric pollutants in terrestrial ecosystems. The aim of this study was to evaluate genotoxicity in the aqueous extract of the native plant, Baccharis trimera, exposed to coal and emissions from a thermal power plant (coal-fired power plant in Candiota, Brazil), correlating seasonality, wind tunnel predominance, and presence of inorganic elements. The presence of inorganic elements in the aerial parts of B. trimera was analyzed by particle-induced X-ray emission (PIXE) spectrometry, and genotoxicity was evaluated by ex vivo comet assay. The genotoxic effects of aqueous extracts of B. trimera from four sites located in the area around power plant were analyzed by comet assay in peripheral human lymphocytes. Winter samples showed greater levels of metals than summer samples. Genotoxicity was detected in B. trimera extracts collected from the region exposed to extraction and burning coal. Extracts from the site impacted by the dominant wind induced more damage to DNA than those from other sites. Based on our data, we can suggest that in winter the inorganic elements from extraction and burning of coal and carried through the wind tunnel were responsible for the genotoxicity observed in aqueous extract of B. trimera.

  2. A Service Oriented Architecture for Exploring High Performance Distributed Power Models

    SciTech Connect

    Liu, Yan; Chase, Jared M.; Gorton, Ian

    2012-11-12

    Power grids are increasingly incorporating high quality, high throughput sensor devices inside power distribution networks. These devices are driving an unprecedented increase in the volume and rate of available information. The real-time requirements for handling this data are beyond the capacity of conventional power models running in central utilities. Hence, we are exploring distributed power models deployed at the regional scale. The connection of these models for a larger geographic region is supported by a distributed system architecture. This architecture is built in a service oriented style, whereby distributed power models running on high performance clusters are exposed as services. Each service is semantically annotated and therefore can be discovered through a service catalog and composed into workflows. The overall architecture has been implemented as an integrated workflow environment useful for power researchers to explore newly developed distributed power models.

  3. Generation of spectrally stable continuous-wave emission and ns pulses with a peak power of 4 W using a distributed Bragg reflector laser and a ridge-waveguide power amplifier.

    PubMed

    Klehr, A; Wenzel, H; Fricke, J; Bugge, F; Erbert, G

    2014-10-01

    We have developed a diode-laser based master oscillator power amplifier (MOPA) light source which emits high-power spectrally stabilized and nearly-diffraction limited optical pulses in the nanoseconds range as required by many applications. The MOPA consists of a distributed Bragg reflector (DBR) laser as master oscillator driven by a constant current and a ridge waveguide power amplifier (PA) which can be driven by a constant current (DC) or by rectangular current pulses with a width of 5 ns at a repetition frequency of 200 kHz. Under pulsed operation the amplifier acts as an optical gate, converting the CW input beam emitted by the DBR laser into a train of short amplified optical pulses. With this experimental MOPA arrangement no relaxation oscillations occur. A continuous wave power of 1 W under DC injection and a pulse power of 4 W under pulsed operation are reached. For both operational modes the optical spectrum of the emission of the amplifier exhibits a peak at a constant wavelength of 973.5 nm with a spectral width < 10 pm.

  4. Adaptable DC offset correction

    NASA Technical Reports Server (NTRS)

    Golusky, John M. (Inventor); Muldoon, Kelly P. (Inventor)

    2009-01-01

    Methods and systems for adaptable DC offset correction are provided. An exemplary adaptable DC offset correction system evaluates an incoming baseband signal to determine an appropriate DC offset removal scheme; removes a DC offset from the incoming baseband signal based on the appropriate DC offset scheme in response to the evaluated incoming baseband signal; and outputs a reduced DC baseband signal in response to the DC offset removed from the incoming baseband signal.

  5. Power distribution in complex environmental negotiations: Does balance matter?

    USGS Publications Warehouse

    Burkardt, N.; Lamb, B.L.; Taylor, J.G.

    1997-01-01

    We studied six interagency negotiations covering Federal Energy Regulatory Commission (FERC) hydroelectric power licenses. Negotiations occurred between state and federal resource agencies and developers over project operations and natural resource mitigation. We postulated that a balance of power among parties was necessary for successful negotiations. We found a complex relationship between balanced power and success and conclude that a balance of power was associated with success in these negotiations. Power played a dynamic role in the bargaining and illuminates important considerations for regulatory design.

  6. Experiments with a DC Motor

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2010-01-01

    Experiments with an electric motor provide good opportunity to demonstrate some basic laws of electricity and magnetism. The aim of the experiments with a low-power dc motor is to show how the motor approaches its steady rotation and how its torque, mechanical power and efficiency depend on the rotation velocity. The tight relationship between the…

  7. Advanced Power Electronics Interfaces for Distributed Energy Workshop Summary: August 24, 2006, Sacramento, California

    SciTech Connect

    Treanton, B.; Palomo, J.; Kroposki, B.; Thomas, H.

    2006-10-01

    The Advanced Power Electronics Interfaces for Distributed Energy Workshop, sponsored by the California Energy Commission Public Interest Energy Research program and organized by the National Renewable Energy Laboratory, was held Aug. 24, 2006, in Sacramento, Calif. The workshop provided a forum for industry stakeholders to share their knowledge and experience about technologies, manufacturing approaches, markets, and issues in power electronics for a range of distributed energy resources. It focused on the development of advanced power electronic interfaces for distributed energy applications and included discussions of modular power electronics, component manufacturing, and power electronic applications.

  8. Power components for the Space Station 20-kHz power distribution system

    NASA Technical Reports Server (NTRS)

    Renz, David D.

    1988-01-01

    Since 1984, NASA Lewis Research Center was developing high power, high frequency space power components as part of The Space Station Advanced Development program. The purpose of the Advanced Development program was to accelerate existing component programs to ensure their availability for use on the Space Station. These components include a rotary power transfer device, remote power controllers, remote bus isolators, high power semiconductor, a high power semiconductor package, high frequency-high power cable, high frequency-high power connectors, and high frequency-high power transformers. All the components were developed to the prototype level and will be installed in the Lewis Research Center Space Station power system test bed.

  9. Power components for the space station 20-kHz power distribution system

    NASA Technical Reports Server (NTRS)

    Renz, David D.

    1988-01-01

    Since 1984, NASA Lewis Research Center was developing high power, high frequency space power components as part of The Space Station Advanced Development program. The purpose of The Advanced Development program was to accelerate existing component programs to ensure their availability for use on the Space Station. These components include a rotary power transfer device, remote power controllers, remote bus isolators, high power semiconductor, a high power semiconductor package, high frequency-high power cable, high frequency-high power connectors, and high frequency-high power transformers. All the components were developed to the prototype level and will be installed in the Lewis Research Center Space Station power system test bed.

  10. Experimental and theoretical study of the radial distribution of Ar(3P0) metastable atoms in a dc glow discharge in argon

    NASA Astrophysics Data System (ADS)

    Grigorian, G. M.; Dyatko, N. A.; Kochetov, I. V.

    2015-11-01

    Radial distributions of the number density of metastable Ar(3P0) atoms in the positive column of a dc glow discharge in argon were studied both experimentally and theoretically in a wide range of gas pressures (0.1-7 Torr) and discharge currents (10-50 mA). In experiments, glass discharge tubes 4 cm in diameter with clean inner surfaces and surfaces covered with a carbonitride or carbon film were utilized. Measurements were performed using an optical absorption technique known as the method of two identical tubes. Theoretical studies of the discharge plasma parameters under experimental conditions were carried out in the framework of a 1D (along the tube radius) discharge model. By a comparison of radial profiles measured and calculated at a gas pressure of 0.1 Torr the probability of elastic (without quenching) reflection of Ar(3P0) atoms from the tube wall was estimated. For a clean tube wall, this probability is about 0.5  ±  0.3, whereas for a wall covered with a carbonitride or carbon film, it is about zero.

  11. Kinetic-Energy Distributions of Positive and Negative Ions in DC Townsend Discharges of CHF3 at High E/N

    NASA Astrophysics Data System (ADS)

    Rao, M. V. V. S.; van Brunt, R. J.; Olthoff, J. K.

    1997-10-01

    In this paper we present ion kinetic-energy distributions (IEDs), mean energies, and relative abundances of CF_3^+, CF_2^+, CF^+, CHF_2^+, CHF^+, CH^+, C^+, H^+, and F- ions produced in dc Townsend discharges in pure CHF_3. The discharges are generated at electric field-to-gas density ratios (E/N) ranging from 5 x 10-18 Vm^2 to 25 x 10-18 Vm^2 (5 to 25 kTd). Ions sampled from the discharge through a small orifice in the center of the grounded electrode were energy and mass analyzed by an electrostatic energy analyzer attached to a quadrupole mass spectrometer.(M. V. V. S. Rao, R. J. Van Brunt, and J. K. Olthoff, Phys. Rev. E 54), 5641 (1996) In the present experiments, CHF_2^+ was determined to be the dominant positive ion at all E/N, followed by CF^+. The negative ion fluxes were substantially lower than the positive ion fluxes, with F^- being the only negative ion with significant intensity. At 5 kTd, the IEDs of all positive ions exhibit Maxwellian behavior. However, at higher E/N the role of collisional dissociation processes increases and the IEDs of the positive ions deviate from those predicted by simple collisional charge-transfer models. The IEDs for F^- are non-maxwellian at all E/N.

  12. Effect of anomalous electron cross-field transport on electron energy distribution function in a DC-RF magnetized plasma discharge

    NASA Astrophysics Data System (ADS)

    Raitses, Yevgeny; Donnelly, Vincent; Kaganovich, Igor; Godyak, Valery

    2013-09-01

    The application of the magnetic field in a low pressure plasma can cause a spatial separation of cold and hot electron groups. This so-called magnetic filter effect is not well understood and is the subject of our studies. In this work, we investigate electron energy distribution function in a DC-RF plasma discharge with crossed electric and magnetic field operating at sub-mtorr pressure range of xenon gas. Experimental studies showed that the increase of the magnetic field leads to a more uniform profile of the electron temperature across the magnetic field. This surprising result indicates the importance of anomalous electron transport that causes mixing of hot and cold electrons. High-speed imaging and probe measurements revealed a coherent structure rotating in E cross B direction with frequency of a few kHz. Similar to spoke oscillations reported for Hall thrusters, this rotating structure conducts the largest fraction of the cross-field current. This work was supported by the US DOE under Contract DE-AC02-09CH11466.

  13. Effect of anomalous electron cross-field transport on electron energy distribution function in a DC-RF magnetized plasma discharge

    NASA Astrophysics Data System (ADS)

    Raitses, Yevgeny; Donnelly, Vincent M.; Kaganovich, Igor D.; Godyak, Valery

    2013-10-01

    The application of the magnetic field in a low pressure plasma can cause a spatial separation of cold and hot electron groups. This so-called magnetic filter effect is not well understood and is the subject of our studies. In this work, we investigate electron energy distribution function in a DC-RF plasma discharge with crossed electric and magnetic field operating at sub-mtorr pressure range of xenon gas. Experimental studies showed that the increase of the magnetic field leads to a more uniform profile of the electron temperature across the magnetic field. This surprising result indicates the importance of anomalous electron transport that causes mixing of hot and cold electrons. High-speed imaging and probe measurements revealed a coherent structure rotating in E cross B direction with frequency of a few kHz. Similar to spoke oscillations reported for Hall thrusters, this rotating structure conducts the largest fraction of the cross-field current. This work was supported by DOE contract DE-AC02-09CH11466.

  14. Nanosecond pulsed electric fields (nsPEFs) low cost generator design using power MOSFET and Cockcroft-Walton multiplier circuit as high voltage DC source

    NASA Astrophysics Data System (ADS)

    Sulaeman, M. Y.; Widita, R.

    2014-09-01

    Purpose: Non-ionizing radiation therapy for cancer using pulsed electric field with high intensity field has become an interesting field new research topic. A new method using nanosecond pulsed electric fields (nsPEFs) offers a novel means to treat cancer. Not like the conventional electroporation, nsPEFs able to create nanopores in all membranes of the cell, including membrane in cell organelles, like mitochondria and nucleus. NsPEFs will promote cell death in several cell types, including cancer cell by apoptosis mechanism. NsPEFs will use pulse with intensity of electric field higher than conventional electroporation, between 20-100 kV/cm and with shorter duration of pulse than conventional electroporation. NsPEFs requires a generator to produce high voltage pulse and to achieve high intensity electric field with proper pulse width. However, manufacturing cost for creating generator that generates a high voltage with short duration for nsPEFs purposes is highly expensive. Hence, the aim of this research is to obtain the low cost generator design that is able to produce a high voltage pulse with nanosecond width and will be used for nsPEFs purposes. Method: Cockcroft-Walton multiplier circuit will boost the input of 220 volt AC into high voltage DC around 1500 volt and it will be combined by a series of power MOSFET as a fast switch to obtain a high voltage with nanosecond pulse width. The motivation using Cockcroft-Walton multiplier is to acquire a low-cost high voltage DC generator; it will use capacitors and diodes arranged like a step. Power MOSFET connected in series is used as voltage divider to share the high voltage in order not to damage them. Results: This design is expected to acquire a low-cost generator that can achieve the high voltage pulse in amount of -1.5 kV with falltime 3 ns and risetime 15 ns into a 50Ω load that will be used for nsPEFs purposes. Further detailed on the circuit design will be explained at presentation.

  15. Nanosecond pulsed electric fields (nsPEFs) low cost generator design using power MOSFET and Cockcroft-Walton multiplier circuit as high voltage DC source

    SciTech Connect

    Sulaeman, M. Y.; Widita, R.

    2014-09-30

    Purpose: Non-ionizing radiation therapy for cancer using pulsed electric field with high intensity field has become an interesting field new research topic. A new method using nanosecond pulsed electric fields (nsPEFs) offers a novel means to treat cancer. Not like the conventional electroporation, nsPEFs able to create nanopores in all membranes of the cell, including membrane in cell organelles, like mitochondria and nucleus. NsPEFs will promote cell death in several cell types, including cancer cell by apoptosis mechanism. NsPEFs will use pulse with intensity of electric field higher than conventional electroporation, between 20–100 kV/cm and with shorter duration of pulse than conventional electroporation. NsPEFs requires a generator to produce high voltage pulse and to achieve high intensity electric field with proper pulse width. However, manufacturing cost for creating generator that generates a high voltage with short duration for nsPEFs purposes is highly expensive. Hence, the aim of this research is to obtain the low cost generator design that is able to produce a high voltage pulse with nanosecond width and will be used for nsPEFs purposes. Method: Cockcroft-Walton multiplier circuit will boost the input of 220 volt AC into high voltage DC around 1500 volt and it will be combined by a series of power MOSFET as a fast switch to obtain a high voltage with nanosecond pulse width. The motivation using Cockcroft-Walton multiplier is to acquire a low-cost high voltage DC generator; it will use capacitors and diodes arranged like a step. Power MOSFET connected in series is used as voltage divider to share the high voltage in order not to damage them. Results: This design is expected to acquire a low-cost generator that can achieve the high voltage pulse in amount of −1.5 kV with falltime 3 ns and risetime 15 ns into a 50Ω load that will be used for nsPEFs purposes. Further detailed on the circuit design will be explained at presentation.

  16. Functional modulation of power-law distribution in visual perception

    NASA Astrophysics Data System (ADS)

    Shimono, Masanori; Owaki, Takashi; Amano, Kaoru; Kitajo, Keiichi; Takeda, Tsunehiro

    2007-05-01

    Neuronal activities have recently been reported to exhibit power-law scaling behavior. However, it has not been demonstrated that the power-law component can play an important role in human perceptual functions. Here, we demonstrate that the power spectrum of magnetoencephalograph recordings of brain activity varies in coordination with perception of subthreshold visual stimuli. We observed that perceptual performance could be better explained by modulation of the power-law component than by modulation of the peak power in particular narrow frequency ranges. The results suggest that the brain operates in a state of self-organized criticality, modulating the power spectral exponent of its activity to optimize its internal state for response to external stimuli.

  17. Generation of spectrally-stable continuous-wave emission and ns pulses at 800 nm and 975 nm with a peak power of 4 W using a distributed Bragg reflector laser and a ridge-waveguide power amplifier

    NASA Astrophysics Data System (ADS)

    Klehr, A.; Wenzel, H.; Fricke, J.; Bugge, F.; Liero, A.; Hoffmann, Th.; Erbert, G.; Tränkle, G.

    2015-03-01

    Semiconductor based sources which emit high-power spectrally stable nearly diffraction-limited optical pulses in the nanosecond range are ideally suited for a lot of applications, such as free-space communications, metrology, material processing, seed lasers for fiber or solid state lasers, spectroscopy, LIDAR and frequency doubling. Detailed experimental investigations of 975 nm and 800 nm diode lasers based on master oscillator power amplifier (MOPA) light sources are presented. The MOPA systems consist of distributed Bragg reflector lasers (DBR) as master oscillators driven by a constant current and ridge waveguide power amplifiers which can be driven DC and by current pulses. In pulse regime the amplifiers modulated with rectangular current pulses of about 5 ns width and a repetition frequency of 200 kHz act as optical gates, converting the continuous wave (CW) input beam emitted by the DBR lasers into a train of short optical pulses which are amplified. With these experimental MOPA arrangements no relaxation oscillations in the pulse power occur. With a seed power of about 5 mW at a wavelength of 973 nm output powers behind the amplifier of about 1 W under DC injection and 4 W under pulsed operation, corresponding to amplification factors of 200 (amplifier gain 23 dB) and 800 (gain 29 dB) respectively, are reached. At 800 nm a CW power of 1 W is obtained for a seed power of 40 mW. The optical spectra of the emission of the amplifiers exhibit a single peak at a constant wavelength with a line width < 10 pm in the whole investigated current ranges. The ratios between laser and ASE levels were > 50 dB. The output beams are nearly diffraction limited with beam propagation ratios M2lat ~ 1.1 and M2ver ~ 1.2 up to 4 W pulse power.

  18. Improving Power Quality in Low-Voltage Networks Containing Distributed Energy Resources

    NASA Astrophysics Data System (ADS)

    Mazumder, Sumit; Ghosh, Arindam; Zare, Firuz

    2013-05-01

    Severe power quality problems can arise when a large number of single-phase distributed energy resources (DERs) are connected to a low-voltage power distribution system. Due to the random location and size of DERs, it may so happen that a particular phase generates excess power than its load demand. In such an event, the excess power will be fed back to the distribution substation and will eventually find its way to the transmission network, causing undesirable voltage-current unbalance. As a solution to this problem, the article proposes the use of a distribution static compensator (DSTATCOM), which regulates voltage at the point of common coupling (PCC), thereby ensuring balanced current flow from and to the distribution substation. Additionally, this device can also support the distribution network in the absence of the utility connection, making the distribution system work as a microgrid. The proposals are validated through extensive digital computer simulation studies using PSCADTM.

  19. Distributed Energy Resources, Power Quality and Reliability - Background

    SciTech Connect

    Schienbein, Lawrence A.; DeSteese, John G.

    2002-01-31

    Power quality [PQ] and power reliability [PR] gained importance in the industrialized world as the pace of installation of sensitive appliances and other electrical loads by utility customers accelerated, beginning in the mid 1980s. Utility-grid-connected customers rapidly discovered that this equipment was increasingly sensitive to various abnormalities in the electricity supply.

  20. Thermoelectric-Generator-Based DC-DC Conversion Networks for Automotive Applications

    NASA Astrophysics Data System (ADS)

    Li, Molan; Xu, Shaohui; Chen, Qiang; Zheng, Li-Rong

    2011-05-01

    Maximizing electrical energy generation through waste heat recovery is one of the modern research questions within automotive applications of thermoelectric (TE) technologies. This paper proposes a novel concept of distributed multisection multilevel DC-DC conversion networks based on thermoelectric generators (TEGs) for automotive applications. The concept incorporates a bottom-up design approach to collect, convert, and manage vehicle waste heat efficiently. Several state-of-the-art thermoelectric materials are analyzed for the purpose of power generation at each waste heat harvesting location on a vehicle. Optimal materials and TE couple configurations are suggested. Moreover, a comparison of prevailing DC-DC conversion techniques was made with respect to applications at each conversion level within the network. Furthermore, higher-level design considerations are discussed according to system specifications. Finally, a case study is performed to compare the performance of the proposed network and a traditional single-stage system. The results show that the proposed network enhances the system conversion efficiency by up to 400%.

  1. Systems analysis of the space shuttle. [communication systems, computer systems, and power distribution

    NASA Technical Reports Server (NTRS)

    Schilling, D. L.; Oh, S. J.; Thau, F.

    1975-01-01

    Developments in communications systems, computer systems, and power distribution systems for the space shuttle are described. The use of high speed delta modulation for bit rate compression in the transmission of television signals is discussed. Simultaneous Multiprocessor Organization, an approach to computer organization, is presented. Methods of computer simulation and automatic malfunction detection for the shuttle power distribution system are also described.

  2. Development of An On-Line, Core Power Distribution Monitoring System

    SciTech Connect

    Tunc ALdemir; Don Miller; Peng Wang

    2007-10-02

    The objective of the proposed work was to develop a software package that can construct in three-dimensional core power distributions using the signals from constant temperature power sensors distributed in the reactor core. The software developed uses a mode-based state/parameter estmation technique that is particularly attractive when there are model uncertainties and/or large signal noise. The software yields the expected value of local power at the detector locations and points in between, as well as the probability distribution of the local power density

  3. DC-DC converters in 0.35μm CMOS technology

    NASA Astrophysics Data System (ADS)

    Michelis, S.; Allongue, B.; Blanchot, G.; Faccio, F.; Fuentes, C.; Orlandi, S.; Saggini, S.; Cengarle, S.; Ongaro, F.

    2012-01-01

    In view of the upgrade of the LHC experiments, we are developing custom DC/DC converters for a more efficient power distribution scheme. A new prototype have been integrated in ASICs in the selected 0.35μm commercial high voltage technology that has been successfully tested for all radiation effects: TID, displacement damage and Single Event Burnout. This converter has been optimized for high efficiency and improved radiation tolerance. Amongst the new features the most relevant are the presence of internal linear regulators, protection circuits with a state-machine and a new pinout for a modified assembly in package in order to reduce conductive losses. This paper illustrates the design of the prototype followed by functional and radiation tests.

  4. Design and modeling of magnetically driven electric-field sensor for non-contact DC voltage measurement in electric power systems

    NASA Astrophysics Data System (ADS)

    Wang, Decai; Li, Ping; Wen, Yumei

    2016-10-01

    In this paper, the design and modeling of a magnetically driven electric-field sensor for non-contact DC voltage measurement are presented. The magnetic drive structure of the sensor is composed of a small solenoid and a cantilever beam with a cylindrical magnet mounted on it. The interaction of the magnet and the solenoid provides the magnetic driving force for the sensor. Employing magnetic drive structure brings the benefits of low driving voltage and large vibrating displacement, which consequently results in less interference from the drive signal. In the theoretical analyses, the capacitance calculation model between the wire and the sensing electrode is built. The expression of the magnetic driving force is derived by the method of linear fitting. The dynamical model of the magnetic-driven cantilever beam actuator is built by using Euler-Bernoulli theory and distributed parameter method. Taking advantage of the theoretical model, the output voltage of proposed sensor can be predicted. The experimental results are in good agreement with the theoretical results. The proposed sensor shows a favorable linear response characteristic. The proposed sensor has a measuring sensitivity of 9.87 μV/(V/m) at an excitation current of 37.5 mA. The electric field intensity resolution can reach 10.13 V/m.

  5. 14 CFR 25.1310 - Power source capacity and distribution.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... functioning normally. (2) Essential loads, after failure of any one prime mover, power converter, or energy storage device. (3) Essential loads after failure of— (i) Any one engine on two-engine airplanes; and...

  6. 14 CFR 25.1310 - Power source capacity and distribution.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... functioning normally. (2) Essential loads, after failure of any one prime mover, power converter, or energy storage device. (3) Essential loads after failure of— (i) Any one engine on two-engine airplanes; and...

  7. 14 CFR 25.1310 - Power source capacity and distribution.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... functioning normally. (2) Essential loads, after failure of any one prime mover, power converter, or energy storage device. (3) Essential loads after failure of— (i) Any one engine on two-engine airplanes; and...

  8. 14 CFR 25.1310 - Power source capacity and distribution.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... functioning normally. (2) Essential loads, after failure of any one prime mover, power converter, or energy storage device. (3) Essential loads after failure of— (i) Any one engine on two-engine airplanes; and...

  9. Space power distribution system technology. Volume 3: Test facility design

    NASA Technical Reports Server (NTRS)

    Decker, D. K.; Cannady, M. D.; Cassinelli, J. E.; Farber, B. F.; Lurie, C.; Fleck, G. W.; Lepisto, J. W.; Messner, A.; Ritterman, P. F.

    1983-01-01

    The AMPS test facility is a major tool in the attainment of more economical space power. The ultimate goals of the test facility, its primary functional requirements and conceptual design, and the major equipment it contains are discussed.

  10. Self-Powered WSN for Distributed Data Center Monitoring

    PubMed Central

    Brunelli, Davide; Passerone, Roberto; Rizzon, Luca; Rossi, Maurizio; Sartori, Davide

    2016-01-01

    Monitoring environmental parameters in data centers is gathering nowadays increasing attention from industry, due to the need of high energy efficiency of cloud services. We present the design and the characterization of an energy neutral embedded wireless system, prototyped to monitor perpetually environmental parameters in servers and racks. It is powered by an energy harvesting module based on Thermoelectric Generators, which converts the heat dissipation from the servers. Starting from the empirical characterization of the energy harvester, we present a power conditioning circuit optimized for the specific application. The whole system has been enhanced with several sensors. An ultra-low-power micro-controller stacked over the energy harvesting provides an efficient power management. Performance have been assessed and compared with the analytical model for validation. PMID:26729135

  11. Self-Powered WSN for Distributed Data Center Monitoring.

    PubMed

    Brunelli, Davide; Passerone, Roberto; Rizzon, Luca; Rossi, Maurizio; Sartori, Davide

    2016-01-01

    Monitoring environmental parameters in data centers is gathering nowadays increasing attention from industry, due to the need of high energy efficiency of cloud services. We present the design and the characterization of an energy neutral embedded wireless system, prototyped to monitor perpetually environmental parameters in servers and racks. It is powered by an energy harvesting module based on Thermoelectric Generators, which converts the heat dissipation from the servers. Starting from the empirical characterization of the energy harvester, we present a power conditioning circuit optimized for the specific application. The whole system has been enhanced with several sensors. An ultra-low-power micro-controller stacked over the energy harvesting provides an efficient power management. Performance have been assessed and compared with the analytical model for validation. PMID:26729135

  12. Self-Powered WSN for Distributed Data Center Monitoring.

    PubMed

    Brunelli, Davide; Passerone, Roberto; Rizzon, Luca; Rossi, Maurizio; Sartori, Davide

    2016-01-02

    Monitoring environmental parameters in data centers is gathering nowadays increasing attention from industry, due to the need of high energy efficiency of cloud services. We present the design and the characterization of an energy neutral embedded wireless system, prototyped to monitor perpetually environmental parameters in servers and racks. It is powered by an energy harvesting module based on Thermoelectric Generators, which converts the heat dissipation from the servers. Starting from the empirical characterization of the energy harvester, we present a power conditioning circuit optimized for the specific application. The whole system has been enhanced with several sensors. An ultra-low-power micro-controller stacked over the energy harvesting provides an efficient power management. Performance have been assessed and compared with the analytical model for validation.

  13. 14 CFR 25.1310 - Power source capacity and distribution.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... functioning normally. (2) Essential loads, after failure of any one prime mover, power converter, or energy storage device. (3) Essential loads after failure of— (i) Any one engine on two-engine airplanes; and...

  14. A MILP-Based Distribution Optimal Power Flow Model for Microgrid Operation

    SciTech Connect

    Liu, Guodong; Starke, Michael R; Zhang, Xiaohu; Tomsovic, Kevin

    2016-01-01

    This paper proposes a distribution optimal power flow (D-OPF) model for the operation of microgrids. The proposed model minimizes not only the operating cost, including fuel cost, purchasing cost and demand charge, but also several performance indices, including voltage deviation, network power loss and power factor. It co-optimizes the real and reactive power form distributed generators (DGs) and batteries considering their capacity and power factor limits. The D-OPF is formulated as a mixed-integer linear programming (MILP). Numerical simulation results show the effectiveness of the proposed model.

  15. Enhancement of Voltage Stability of DC Smart Grid During Islanded Mode by Load Shedding Scheme

    NASA Astrophysics Data System (ADS)

    Nassor, Thabit Salim; Senjyu, Tomonobu; Yona, Atsushi

    2015-10-01

    This paper presents the voltage stability of a DC smart grid based on renewable energy resources during grid connected and isolated modes. During the islanded mode the load shedding, based on the state of charge of the battery and distribution line voltage, was proposed for voltage stability and reservation of critical load power. The analyzed power system comprises a wind turbine, a photovoltaic generator, storage battery as controllable load, DC loads, and power converters. A fuzzy logic control strategy was applied for power consumption control of controllable loads and the grid-connected dual active bridge series resonant converters. The proposed DC Smart Grid operation has been verified by simulation using MATLAB® and PLECS® Blockset. The obtained results show the effectiveness of the proposed method.

  16. [Comparison of texture distribution of cold rolled DC and CC AA 5052 aluminum alloy at different positions through thickness direction by XRD].

    PubMed

    Chen, Ming-biao; Ma, Min; Yang, Qing-xiang; Wang, Shan; Liu, Wen-chang; Zhao, Ying-mei

    2013-09-01

    To provide gist of DC AA 5052 and CC AA 5052 aluminum alloy to industry production and application, the texture variation of cold rolled sheets through thickness direction was studied by X-ray diffraction method, and the difference in texture at surface, quarter and center layer was analyzed. The hot plates of direct chill cast (DC) AA 5052 and continuous cast (CC) AA 5052 aluminum alloy were annealed at 454 degrees C for 4 hours and then cold rolled to different reductions. The strength and volume fraction of the fiber in CC AA 5052 aluminum alloy is larger than in DC AA 5052 aluminum alloy after same rolling reduction The volume fraction of the recrystallization texture cube in the CC AA 5052 aluminum alloy is less than in the DC AA 5052 aluminum alloy, which result in that CC AA 5052 aluminum alloy needs less cold rolling reduction than DC AA 5052 aluminum alloy for generating the texture with same intensity and volume fraction at surface layer, quarter layer and center layer. The manufacturability and performance of CC AA 5052 aluminum alloy is superior to DC AA 5052 aluminum alloy for use in stamping.

  17. Current Fed Step-up DC/DC Converter for Fuel Cell Inverter Applications

    NASA Astrophysics Data System (ADS)

    Andreičiks, Aleksandrs; Vitols, Kristaps; Krievs, Oskars; Steiks, Ingars

    2009-01-01

    In order to use hydrogen fuel cells in domestic applications either as main power supply or backup source, their low DC output voltage has to be matched to the level and frequency of the utility grid AC voltage. Such power converter systems usually consist of a DC-DC converter and a DC-AC inverter. Comparison of different current fed step-up DC/DC converters is done in this paper and a double inductor step-up push-pull converter investigated, presenting simulation and experimental results. The converter is elaborated for 1200 W power to match the rated power of the proton exchange membrane (PEM) fuel cell located in hydrogen fuel cell research laboratory of Riga Technical University.

  18. Model predictive control of bidirectional isolated DC-DC converter for energy conversion system

    NASA Astrophysics Data System (ADS)

    Akter, Parvez; Uddin, Muslem; Mekhilef, Saad; Tan, Nadia Mei Lin; Akagi, Hirofumi

    2015-08-01

    Model predictive control (MPC) is a powerful and emerging control algorithm in the field of power converters and energy conversion systems. This paper proposes a model predictive algorithm to control the power flow between the high-voltage and low-voltage DC buses of a bidirectional isolated full-bridge DC-DC converter. The predictive control algorithm utilises the discrete nature of the power converters and predicts the future nature of the system, which are compared with the references to calculate the cost function. The switching state that minimises the cost function is selected for firing the converter in the next sampling time period. The proposed MPC bidirectional DC-DC converter is simulated with MATLAB/Simulink and further verified with a 2.5 kW experimental configuration. Both the simulation and experimental results confirm that the proposed MPC algorithm of the DC-DC converter reduces reactive power by avoiding the phase shift between primary and secondary sides of the high-frequency transformer and allow power transfer with unity power factor. Finally, an efficiency comparison is performed between the MPC and dual-phase-shift-based pulse-width modulation controlled DC-DC converter which ensures the effectiveness of the MPC controller.

  19. Simulation of a Lunar Surface Base Power Distribution Network for the Constellation Lunar Surface Systems

    NASA Technical Reports Server (NTRS)

    Mintz, Toby; Maslowski, Edward A.; Colozza, Anthony; McFarland, Willard; Prokopius, Kevin P.; George, Patrick J.; Hussey, Sam W.

    2010-01-01

    The Lunar Surface Power Distribution Network Study team worked to define, breadboard, build and test an electrical power distribution system consistent with NASA's goal of providing electrical power to sustain life and power equipment used to explore the lunar surface. A testbed was set up to simulate the connection of different power sources and loads together to form a mini-grid and gain an understanding of how the power systems would interact. Within the power distribution scheme, each power source contributes to the grid in an independent manner without communication among the power sources and without a master-slave scenario. The grid consisted of four separate power sources and the accompanying power conditioning equipment. Overall system design and testing was performed. The tests were performed to observe the output and interaction of the different power sources as some sources are added and others are removed from the grid connection. The loads on the system were also varied from no load to maximum load to observe the power source interactions.

  20. Galileo spacecraft power distribution and autonomous fault recovery

    NASA Technical Reports Server (NTRS)

    Detwiler, R. C.

    1982-01-01

    There is a trend in current spacecraft design to achieve greater fault tolerance through the implemenation of on-board software dedicated to detecting and isolating failures. A combination of hardware and software is utilized in the Galileo power system for autonomous fault recovery. Galileo is a dual-spun spacecraft designed to carry a number of scientific instruments into a series of orbits around the planet Jupiter. In addition to its self-contained scientific payload, it will also carry a probe system which will be separated from the spacecraft some 150 days prior to Jupiter encounter. The Galileo spacecraft is scheduled to be launched in 1985. Attention is given to the power system, the fault protection requirements, and the power fault recovery implementation.