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Sample records for inverter designed dc

  1. 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.

  2. Multilevel DC link inverter

    DOEpatents

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  3. Design of a ZVS PWM inverter for a brushless DC motor in an EMA application

    NASA Technical Reports Server (NTRS)

    Bell, J. Brett; Nelms, R. M.; Shepherd, Michael T.

    1993-01-01

    The Component Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently investigating the use of electromechanical actuators for use in space transportation applications such as Thrust Vector Control (TVC). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 Vdc. This paper will discuss the design and implementation of a zero-voltage-switched PWM (Pulse Width Modulation) inverter which operates from a 270 Vdc source at currents up to 100 A.

  4. Design of a ZVS PWM inverter for a brushless DC motor in an EMA application

    NASA Astrophysics Data System (ADS)

    Bell, J. Brett; Nelms, R. M.; Shepherd, Michael T.

    The Component Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently investigating the use of electromechanical actuators for use in space transportation applications such as Thrust Vector Control (TVC). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 Vdc. This paper will discuss the design and implementation of a zero-voltage-switched PWM (Pulse Width Modulation) inverter which operates from a 270 Vdc source at currents up to 100 A.

  5. Efficient/reliable dc-to-dc inverter circuit

    NASA Technical Reports Server (NTRS)

    Pasciutti, E. R.

    1970-01-01

    Feedback loop, which contains an inductor in series with a saturable reactor, is added to a standard inverter circuit to permit the inverter power transistors to be switched in a controlled and efficient manner. This inverter is applicable where the power source has either high or low impedance properties.

  6. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    2002-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  7. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    1997-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  8. Multilevel cascade voltage source inverter with separate DC sources

    DOEpatents

    Peng, F.Z.; Lai, J.S.

    1997-06-24

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

  9. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    2001-04-03

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  10. 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.

  11. DC-AC Cascaded H-Bridge Multilevel Boost Inverter With No Inductors for Electric/Hybrid Electric Vehicle Applications

    SciTech Connect

    Tolbert, Leon M; Ozpineci, Burak; Du, Zhong; Chiasson, John N

    2009-01-01

    This paper presents a cascaded H-bridge multilevel boost inverter for electric vehicle (EV) and hybrid EV (HEV) applications implemented without the use of inductors. Currently available power inverter systems for HEVs use a dc-dc boost converter to boost the battery voltage for a traditional three-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky inductor. A cascaded H-bridge multilevel boost inverter design for EV and HEV applications implemented without the use of inductors is proposed in this paper. Traditionally, each H-bridge needs a dc power supply. The proposed design uses a standard three-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg which uses a capacitor as the dc power source. A fundamental switching scheme is used to do modulation control and to produce a five-level phase voltage. Experiments show that the proposed dc-ac cascaded H-bridge multilevel boost inverter can output a boosted ac voltage without the use of inductors.

  12. A single-phase embedded Z-source DC-AC inverter.

    PubMed

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  13. A Single-Phase Embedded Z-Source DC-AC Inverter

    PubMed Central

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  14. Efficiency consideration of DC link soft-switching inverters for motor drive applications

    SciTech Connect

    Lai, J.S.; Young, R.W.; McKeever, J.W.

    1994-12-31

    This paper critically evaluates efficiency of soft switching inverters including an actively clamped resonant dc link inverter and a clamped-mode resonant pole inverter. An analytical approach to evaluating efficiency of the clamped-mode soft switching inverter has been developed. The evaluation results are compared with that of the standard pulse-width-modulation (PWM) inverter. A 50-kW induction motor is used as the variable load, and the inverter efficiency is evaluated under different speed and torque conditions. The clamped-mode soft-switching inverter, although eliminating the switching loss, shows poor efficiency over the entire load range. Under low load conditions, the efficiency profile is even worse. The actively clamped resonant dc link inverter shows highest efficiency over the entire speed and torque range. However, its energy saving over the standard PWM inverter is marginal under full load or high speed conditions.

  15. A multilevel voltage-source inverter with separate dc sources for static var generation

    SciTech Connect

    Peng, Fang Zheng |; Lai, Jih-Sheng; McKeever, J.; VanCoevering, J.

    1995-09-01

    A new multilevel voltage-source inverter with a separate dc sources is proposed for high-voltage, high-power applications, such as flexible ac transmission systems (FACTS) including static var generation (SVG), power line conditioning, series compensation, phase shifting, voltage balancing, fuel cell and photovoltaic utility systems interfacing, etc. The new M-level inverter consists of (M-1)/2 single phase full bridges in which each bridge has its own separate dc source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle as the number of levels increases. It can solve the problems of conventional transformer-based multipulse inverters and the problems of the multilevel diode-clamped inverter and the multilevel flying capacitor inverter. To demonstrate the superiority of the new inverter, a SVG system using the new inverter topology is discussed through analysis, simulation and experiment.

  16. DC-to-AC inverter ratio failure detector

    NASA Technical Reports Server (NTRS)

    Ebersole, T. J.; Andrews, R. E.

    1975-01-01

    Failure detection technique is based upon input-output ratios, which is independent of inverter loading. Since inverter has fixed relationship between V-in/V-out and I-in/I-out, failure detection criteria are based on this ratio, which is simply inverter transformer turns ratio, K, equal to primary turns divided by secondary turns.

  17. Digital DC-Reconstruction of AC-Coupled Electrophysiological Signals with a Single Inverting Filter

    PubMed Central

    Schmid, Ramun; Leber, Remo; Schmid, Hans-Jakob; Generali, Gianluca

    2016-01-01

    Since the introduction of digital electrocardiographs, high-pass filters have been necessary for successful analog-to-digital conversion with a reasonable amplitude resolution. On the other hand, such high-pass filters may distort the diagnostically significant ST-segment of the ECG, which can result in a misleading diagnosis. We present an inverting filter that successfully undoes the effects of a 0.05 Hz single pole high-pass filter. The inverting filter has been tested on more than 1600 clinical ECGs with one-minute durations and produces a negligible mean RMS-error of 3.1*10−8 LSB. Alternative, less strong inverting filters have also been tested, as have different applications of the filters with respect to rounding of the signals after filtering. A design scheme for the alternative inverting filters has been suggested, based on the maximum strength of the filter. With the use of the suggested filters, it is possible to recover the original DC-coupled ECGs from AC-coupled ECGs, at least when a 0.05 Hz first order digital single pole high-pass filter is used for the AC-coupling. PMID:26938769

  18. Adaptive Selective Harmonic Minimization Based on ANNs for Cascade Multilevel Inverters With Varying DC Sources

    SciTech Connect

    Filho, Faete; Maia, Helder Z; Mateus, Tiago Henrique D; Ozpineci, Burak; Tolbert, Leon M; Pinto, Joao Onofre P

    2013-01-01

    A new approach for modulation of an 11-level cascade multilevel inverter using selective harmonic elimination is presented in this paper. The dc sources feeding the multilevel inverter are considered to be varying in time, and the switching angles are adapted to the dc source variation. This method uses genetic algorithms to obtain switching angles offline for different dc source values. Then, artificial neural networks are used to determine the switching angles that correspond to the real-time values of the dc sources for each phase. This implies that each one of the dc sources of this topology can have different values at any time, but the output fundamental voltage will stay constant and the harmonic content will still meet the specifications. The modulating switching angles are updated at each cycle of the output fundamental voltage. This paper gives details on the method in addition to simulation and experimental results.

  19. Mathematical model for the dc-ac inverter for the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Berry, Frederick C.

    1987-01-01

    The reader is informed of what was done for the mathematical modeling of the dc-ac inverter for the Space Shuttle. The mathematical modeling of the dc-ac inverter is an essential element in the modeling of the electrical power distribution system of the Space Shuttle. The electrical power distribution system which is present on the Space Shuttle is made up to 3 strings each having a fuel cell which provides dc to those systems which require dc, and the inverters which convert the dc to ac for those elements which require ac. The inverters are units which are 2 wire structures for the main dc inputs and 2 wire structures for the ac output. When 3 are connected together a 4 wire wye connection results on the ac side. The method of modeling is performed by using a Least Squares curve fitting method. A computer program is presented for implementation of the model along with graphs and tables to demonstrate the accuracy of the model.

  20. Designing dc Inductors With Airgaps

    NASA Technical Reports Server (NTRS)

    Wagner, A. P.

    1986-01-01

    Optimal parameters obtained designing near saturation point. New iterative procedure aids design of dc inductors with airgaps in cores. For given core area and length, technique gives design having specified inductance and peak flux density in core, using minimum required copper weight. Executed rapidly on programmable, hand-held calculator. Applications include lightweight inductors for aircraft electronics.

  1. Novel DC-rail soft-switched three-phase voltage-source inverters

    SciTech Connect

    Wang, K.; Jiang, Y.; Dubovsky, S.; Hua, G.; Boroyevich, D.; Lee, F.C.

    1995-12-31

    A family of dc-rail soft-switched three-phase voltage-source inverters (VSIs) adopting the zero-voltage-transition (ZVT) or zero-current-transition (ZCT) techniques are proposed in this paper. Adding an active switch on the dc-rail makes the implementation of the ZVT and ZCT as easy as in a single-ended d/dc converter, while true pulse-width-modulation (PWM) operation is achieved by a modified space-vector modulation. As a result, these inverters can run at much higher switching frequencies than the conventional hard-switched VSIs, and with higher power density and efficiency. The operation and control strategy of a prototype dc-rail ZVT VSI, which is rated at 15 kVA and run at a switching frequency of 62.5 kHz, are presented. The measured efficiency with static loads reaches 93% under the input voltage of 400 V.

  2. Inverter design for high frequency power distribution

    NASA Technical Reports Server (NTRS)

    King, R. J.

    1985-01-01

    A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

  3. An integrated technique for eliminating harmonics of multilevel inverter with unequal DC sources

    NASA Astrophysics Data System (ADS)

    Malarvizhi, M.; Gnanambal, I.

    2015-02-01

    For improving the alteration performance of multilevel inverter, selective harmonics elimination methods play a significant role. In this document, an incorporated method is suggested for removing the harmonics of multilevel inverter with uneven DC sources. The suggested incorporated method is the mixture of fuzzy logic intelligent system and particle swarm optimisation (PSO) algorithm. For generating the training information set in terms of switching angle, Fuzzy is one of the synthetic intelligent methods which apply harmonic voltage and harmonic distortion. PSO is one of the swarm intelligence-based optimisation algorithms which is employed for choosing optimal switching angle from the training data set. The suggested hybrid method is executed in MATLAB/Simulink platform. At dissimilar unequal input voltage levels, the performance of the suggested method is checked by cascade H-bridge multilevel inverter. The production of the suggested method is compared with the theoretical effects.

  4. Approaches to Suppressing Shaft Voltage in Brushless DC Motor Driven by PWM Inverter

    NASA Astrophysics Data System (ADS)

    Iimori, Kenichi; Shinohara, Katsuji; Yamamoto, Kichiro; Morigami, Atsushi

    This paper describes the approaches to suppressing the shaft voltage and bearing current by electrostatic shielding the stator end windings of the brushless DC motor driven by PWM inverter. At first, measured shaft voltage and bearing current are compared with those calculated waveforms to verify the common mode equivalent circuit of the brushless DC motor. Next, relationship between shaft voltage and stator winding to rotor capacitance is calculated using the common mode equivalent circuit. Finally, the electrostatic shielding of the stator end windings is evaluated to reduce the shaft voltage by experiments and calculations.

  5. 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.

  6. 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.

  7. Design and material selection for inverter transformer cores

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1973-01-01

    Report is announced which studied magnetic properties of candidate materials for use in spacecraft transformers, static inverters, converters, and transformer-rectifier power supplies. Included are material characteristics for available alloy compositions in tabular form, including: trade names, saturated flux density, dc coercive force, loop squareness, material density, and watts per pound at 3 KHz.

  8. 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.

  9. Extended Constant Power Speed Range of the Brushless DC Motor Through Dual Mode Inverter Control

    SciTech Connect

    Lawler, J.S.

    2000-06-23

    The trapezoidal back electromotive force (emf) brushless direct current (dc) motor (BDCM) with surface-mounted magnets has high-power density and efficiency especially when rare-earth magnet materials are used. Traction applications, such as electric vehicles, could benefit significantly from the use of such motors. Unfortunately, a practical means for driving the motor over a constant power speed ratio (CPSR) of 5:1 or more has not yet been developed. A key feature of these motors is that they have low internal inductance. The phase advance method is effective in controlling the motor power over such a speed range, but the current at high speed may be several times greater than that required at the base speed. The increase in current during high-speed operation is due to the low motor inductance and the action of the bypass diodes of the inverter. The use of such a control would require increased current rating of the inverter semiconductors and additional cooling for the inverter, where the conduction losses increase proportionally with current, and especially for the motor, where the losses increase with the square of the current. The high current problems of phase advance can be mitigated by adding series inductance; however, this reduces power density, requires significant increase in supply voltage, and leaves the CPSR performance of the system highly sensitive to variations in the available voltage. A new inverter topology and control scheme has been developed that can drive low-inductance BDCMs over the CPSR that would be required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC). It is shown that the BDCM has an infinite CPSR when it is driven by the DMIC.

  10. A Five-Level Cascade Multilevel Inverter Three-Phase Motor Drive Using a Single DC Source

    SciTech Connect

    Chiasson, J. N.

    2006-10-01

    A method is presented showing that a 5-level cascade multilevel inverter for a three-phase permanent magnet sychronous motor drive can be implemented using only a single DC link to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. It is shown that the capacitor voltages can be regulated while achieving an output voltage waveform that is 20% greater than that obained using the standard 3-leg inverter alone. Finally conditions are given in terms of the power factor and modulation index that determine when the capacitor voltage can regulated.

  11. A Five-Level Three-Phase Cascade Multilevel Inverter Using a Single DC Source for a PM Synchronous Motor Drive

    SciTech Connect

    Ozpineci, Burak; Chiasson, John N; Tolbert, Leon M

    2007-01-01

    The interest here is in using a single DC power source to construct a 3-phase 5-level cascade multilevel inverter to be used as a drive for a PM traction motor. The 5-level inverter consists of a standard 3-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg, which use a capacitor as a DC source. It is shown that one can simultaneously maintain the regulation of the capacitor voltage while achieving an output voltage waveform which is 25% higher than that obtained using a standard 3-leg inverter by itself.

  12. Design of single phase inverter using microcontroller assisted by data processing applications software

    NASA Astrophysics Data System (ADS)

    Ismail, K.; Muharam, A.; Amin; Widodo Budi, S.

    2015-12-01

    Inverter is widely used for industrial, office, and residential purposes. Inverter supports the development of alternative energy such as solar cells, wind turbines and fuel cells by converting dc voltage to ac voltage. Inverter has been made with a variety of hardware and software combinations, such as the use of pure analog circuit and various types of microcontroller as controller. When using pure analog circuit, modification would be difficult because it will change the entire hardware components. In inverter with microcontroller based design (with software), calculations to generate AC modulation is done in the microcontroller. This increases programming complexity and amount of coding downloaded to the microcontroller chip (capacity flash memory in the microcontroller is limited). This paper discusses the design of a single phase inverter using unipolar modulation of sine wave and triangular wave, which is done outside the microcontroller using data processing software application (Microsoft Excel), result shows that complexity programming was reduce and resolution sampling data is very influence to THD. Resolution sampling must taking ½ A degree to get best THD (15.8%).

  13. Performance analysis of cascaded h-bridge multilevel inverter using mixed switching frequency with various dc-link voltages

    NASA Astrophysics Data System (ADS)

    Citarsa, I. B. F.; Satiawan, I. N. W.; Wiryajati, I. K.; Supriono

    2016-01-01

    Multilevel inverters have been widely used in many applications since the technology is advantageous to increase the converter capability as well as to improve the output voltage quality. According to the applied switching frequency, multilevel modulations can be subdivided into three classes, i.e: fundamental switching frequency, high switching frequency and mixed switching frequency. This paper investigates the performance of cascaded H-bridge (CHB) multilevel inverter that is modulated using mixed switching frequency (MSF) PWM with various dc-link voltage ratios. The simulation results show the nearly sinusoidal load output voltages are successfully achieved. It is revealed that there is improvement in output voltages quality in terms of THD and low-order harmonics content. The CHB inverter that is modulated using MSF PWM with equal dc-link voltage ratio (½ Vdc: ½ Vdc) produces output voltage with the lowest low-order harmonics (less than 1% of fundamental) while the CHB inverter that is modulated using MSF PWM with un-equal dc-link voltage ratio (2/3 Vdc: 1/3 Vdc) produces a 7-level output voltage with the lowest THD (16.31%) compared to the other PWM methods. Improvement of the output voltage quality here is also in line with improvement of the number of available levels provided in the output voltage. Here only 2 cells H-bridge inverter (contain 8 switches) are needed to produce a 7- level output voltage, while in the conventional CHB inverter at least 3 cells of H-bridge inverter (contain 12 switches) are needed to produce a 7-level output voltage. Hence it is valuable in term of saving number of component.

  14. A DC-Voltage-Balancing Circuit for a Five-Level Diode-Clamped PWM Inverter Intended for Motor Drives

    NASA Astrophysics Data System (ADS)

    Hasegawa, Kazunori; Akagi, Hirofumi

    This paper proposes a new dc-voltage-balancing circuit for a five-level diode-clamped inverter intended for a medium-voltage motor drive. This circuit consists of two unidirectional choppers and a single coupled inductor with two galvanically-isolated windings. The dc magnetic fluxes in the magnetic core, which are generated by the two windings, cancel out each other. Therefore, the inductor does not generate any dc-magnetic flux in the magnetic core. This makes the inductor compact by a factor of six compared to previously used balancing circuits containing two non-coupled inductors. Experimental results obtained from a 200-V 5.5-kW downscaled model verify that the dc mean voltages of the four split dc capacitors are balanced well under all operating conditions.

  15. The analysis and design of brushless D.C. motors

    NASA Astrophysics Data System (ADS)

    Benarous, Maamar

    In modern computer systems electrical drives are used to rotate hard discs. These motors require special torque- speed characteristics. The speed of the hard disc must be constant in order for the unit to function correctly. One type of drive, which is used for hard discs is the brushless-DC-motor. This machine has permanent magnet excitation and a polyphase armature winding. It therefore takes the form of a synchronous machine, and in order to be brushless the armature winding is stationary and the excitation rotates. To run at adjustable speed a variable frequency supply is required. In the brushless D.C form the inverter output is phase locked to the rotor position, it is therefore electro-magnetically similar to the D.C machine where fixed brushes determine the frequency and phase of the current in the armature winding. In order to perform the phase lock action signals measuring the rotor position are needed. In one form of machine Hall effect probes detect the position of the rotor poles, in a second given that the rotor is in motion the induced back emf is used. Experimentally it is convenient to replace these magnet systems with a photo- transistor and rotating shutter system and this was the approach used in this thesis. The objective of this research is to investigate different aspects of this motor. The generation, measurement, and placement of signals is described and illustrated, and the design and construction of an inverter supply circuit is described. Both 2D and 3D finite element analysis is used in order to find the machine parameters as well as cogging torque analysis, using the concept of permanent magnet magnetisation characteristics. It is shown that the cogging can be reduced for certain types of magnetisation. The finite element analysis is taken further by connecting the drive circuit needed to run the machine into the finite element mesh, the machine parameters are defined using this method. The close agreement between the simulation and

  16. A Novel Inductor-less DC-AC Cascaded H-bridge Multilevel Boost Inverter for Electric/Hybrid Electric Vehicle Applications

    SciTech Connect

    Du, Zhong; Ozpineci, Burak; Tolbert, Leon M; Chiasson, John N

    2007-01-01

    This paper presents an inductorless cascaded H- bridge multilevel boost inverter for EV and HEV applications. Currently available power inverter systems for HEVs use a DC- DC boost converter to boost the battery voltage for a traditional 3-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky inductor. An inductorless cascaded H-bridge multilevel boost inverter for EV and HEV applications is proposed in this paper. Traditionally, each H-bridge needs a DC power supply. The proposed inductorless cascaded H-bridge multilevel boost inverter uses a standard 3-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg which uses a capacitor as the DC power source. Fundamental switching scheme is used to do modulation control and to produce a 5-level phase voltage. Experiments show that the proposed inductorless DC-AC cascaded H-bridge multilevel boost inverter can output a boosted AC voltage.

  17. Toroidal transformer design program with application to inverter circuitry

    NASA Technical Reports Server (NTRS)

    Dayton, J. A., Jr.

    1972-01-01

    Estimates of temperature, weight, efficiency, regulation, and final dimensions are included in the output of the computer program for the design of transformers for use in the basic parallel inverter. The program, written in FORTRAN 4, selects a tape wound toroidal magnetic core and, taking temperature, materials, core geometry, skin depth, and ohmic losses into account, chooses the appropriate wire sizes and number of turns for the center tapped primary and single secondary coils. Using the program, 2- and 4-kilovolt-ampere transformers are designed for frequencies from 200 to 3200 Hz and the efficiency of a basic transistor inverter is estimated.

  18. Optimum Design of CMOS DC-DC Converter for Mobile Applications

    NASA Astrophysics Data System (ADS)

    Katayama, Yasushi; Edo, Masaharu; Denta, Toshio; Kawashima, Tetsuya; Ninomiya, Tamotsu

    In recent years, low output power CMOS DC-DC converters which integrate power stage MOSFETs and a PWM controller using CMOS process have been used in many mobile applications. In this paper, we propose the calculation method of CMOS DC-DC converter efficiency and report optimum design of CMOS DC-DC converter based on this method. By this method, converter efficiencies are directly calculated from converter specifications, dimensions of power stage MOSFET and device parameters. Therefore, this method can be used for optimization of CMOS DC-DC converter design, such as dimensions of power stage MOSFET and switching frequency. The efficiency calculated by the proposed method agrees well with the experimental results.

  19. Design and analysis of controllers for a double inverted pendulum.

    PubMed

    Niemann, Henrik; Poulsen, Jesper Kildegaard

    2005-01-01

    A physical control problem is studied with the Hinfinity, and the micro methodology. The issues of modeling, uncertainty modeling, performance specification, controller design, and laboratory implementation are discussed. The laboratory experiment is a double inverted pendulum placed on a cart. The limitations in the system with respect to performance are the limitation in the control signal and the limitation of the movement of the cart. It is shown how these performance limitations will effect the design of Hinfinity and micro controllers for the system. PMID:15682623

  20. 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.

  1. Design of a three-phase, 15-kilovolt-ampere static inverter for motor-starting a Brayton space power system

    NASA Technical Reports Server (NTRS)

    Frye, R. J.; Birchenough, A. G.

    1971-01-01

    The design of a three-phase, 400-Hz, 15-kVA static inverter for motor-starting the 2- to 15-kWe Brayton electrical space power system is described. The inverter operates from a nominal 56-V dc source to provide a 28-V, rms, quasi-square-wave output. The inverter is capable of supplying a 200-A peak current. Integrated circuitry is used to generate the three-phase, 400-Hz reference signals. Performance data for a drive stage that improves switching speed and provides efficient operation over a range of output current and drive supply voltage are presented. A transformerless, transistor output stage is used.

  2. An enhanced Z-source inverter topology-based permanent magnet brushless DC motor drive speed control

    NASA Astrophysics Data System (ADS)

    Geno Peter, P.; Rajaram, M.

    2015-08-01

    In this paper, an enhanced Z-source inverter (ZSI) is introduced for controlling the speed of permanent magnet brushless DC motor (PMBLDCM) drive. It is the extension of the conventional ZSI and the elements used in the circuit are the same as those of the conventional ZSI, except that the position of Inverter Bridge and diode would be exchanged from the classical circuit diagram. This exchanged circuit avoids the startup path of the inrush current and hence reduces the inrush current and improves the motor efficiency. Different modes of enhanced ZSI are studied with PMBLDCM. The voltage polarity of Z-source capacitors in the proposed circuit is the same as that of the input voltage polarity. Furthermore, to get the same voltage boost, the capacitor voltage stress is reduced to a significant extent. The speed control capability of the proposed brushless DC motor drive is compared with that of the conventional ZSI. The proposed ZSI is implemented in MATLAB/Simulink working platform and the output performance is evaluated. Also, the performance of voltage ratio is analysed both by simulation and mathematical models. All these analyses are known to express the innovative features of the proposed system.

  3. GAP analysis towards a design qualification standard development for grid-connected photovoltaic inverters.

    SciTech Connect

    Tamizhmani, Govindasamy; Granata, Jennifer E.; Maracas, George; Ayyanar, Raja; Marinella, Matthew; Venkataramanan, Sai Balasubramanian Alampoondi

    2011-06-01

    A dedicated design qualification standard for PV inverters does not exist. Development of a well-accepted design qualification standard, specifically for PV inverters will significantly improve the reliability and performance of inverters. The existing standards for PV inverters such as ANSI/UL 1741 and IEC 62109-1 primarily focus on safety of PV inverters. The IEC 62093 discusses inverter qualification but it includes all the BOS components. There are other general standards for distributed generators including the IEEE 1547 series of standards which cover major concerns like utility integration but they are not dedicated to PV inverters and are not written from a design qualification point of view. In this paper some of the potential requirements for a design qualification standard for PV inverters are addressed. The missing links in existing PV inverter related standards are identified and with the IEC 62093 as a guideline, the possible inclusions in the framework for a dedicated design qualification standard of PV inverter are discussed. Some of the key missing links are related to electric stress tests. Hence, a method to adapt the existing surge withstand test standards for use in design qualification standard of PV inverter is presented.

  4. Multilevel-Dc-Bus Inverter For Providing Sinusoidal And Pwm Electrical Machine Voltages

    DOEpatents

    Su, Gui-Jia [Knoxville, TN

    2005-11-29

    A circuit for controlling an ac machine comprises a full bridge network of commutation switches which are connected to supply current for a corresponding voltage phase to the stator windings, a plurality of diodes, each in parallel connection to a respective one of the commutation switches, a plurality of dc source connections providing a multi-level dc bus for the full bridge network of commutation switches to produce sinusoidal voltages or PWM signals, and a controller connected for control of said dc source connections and said full bridge network of commutation switches to output substantially sinusoidal voltages to the stator windings. With the invention, the number of semiconductor switches is reduced to m+3 for a multi-level dc bus having m levels. A method of machine control is also disclosed.

  5. Nongrounded Common-Mode Equivalent Circuit for Brushless DC Motor Driven by PWM Inverter

    NASA Astrophysics Data System (ADS)

    Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo

    This paper describes nongrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was small, the phenomenon that polarity of the common mode voltage and shaft voltage reversed was observed. In order to model this phenomenon, the bridge type equivalent circuit is proposed. It is verified with the calculation and experiment that shaft voltage values and polarity are accurately calculated with the proposed equivalent circuit.

  6. CMOS inverter design-hardened to the total dose effect

    SciTech Connect

    Roche, F.M.; Salager, L.

    1996-12-01

    This paper reports and discusses the experimental behavior of two inverter structures Rad-Hardened by Design to {sup 60}Co irradiation. The authors use the results on a set of basic circuits and transistors exposed to the same total doses as these structures to establish the effective formation conditions of the parasitic channel. Then this leakage evolution is related to the gate voltage history under irradiation. Finally, they take advantage of this intrinsic degradation property to propose a new Design Rad Hardened (DRH) cell. This structure considerably limits the Low Noise Margin degradation, helps to maintain the logic functionality with a High Output level and improves both the rad-tolerance and the static power consumption.

  7. 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.

  8. Technology of Performance Improvement Brushless DC Motors and Inverter for Air conditioning

    NASA Astrophysics Data System (ADS)

    Baba, Kazuhiko; Matsuoka, Atsushi; Shinomoto, Yosuke; Arisawa, Koichi

    High efficiency motors are demanded because of the viewpoint of environmental preservation. It is necessary to develop the technology of the energy conservation that can be achieved at low cost so that we may expand high efficiency motors onto the world. In this paper, the current status of the brushless DC motors and invertors to satisfy high efficiency, small size, high power and low cost is reviewed.

  9. Development of a fuzzy logic controller for dc/dc converters: Design, computer simulation, and experimental evaluation

    SciTech Connect

    So, W.C.; Tse, C.K.; Lee, Y.S.

    1996-01-01

    The design of a fuzzy logic controller for dc/dc converters is described in this paper. A brief review of fuzzy logic and its application to control is first given. Then, the derivation of a fuzzy control algorithm for regulating dc/dc converters is described in detail. The proposed fuzzy control is evaluated by computer simulations as well as experimental measurements of the closed-loop performance of simple dc/dc converters in respect of load regulation and line regulation.

  10. Linearized stability analysis and design of a flyback dc-dc boost regulator.

    NASA Technical Reports Server (NTRS)

    Wester, G. W.

    1973-01-01

    Analytic expressions for the small-signal power-stage describing functions of a switched dc-dc boost regulator are derived from an approximate continuous circuit model which is developed by a time-averaging technique. Closed-loop stability is attained through the design of frequency compensation of the loop gain. Open- and closed-loop regulator output impedances are derived from the linearized models for the given configuration. The analysis and design are compared with and confirmed by breadboard measurements.

  11. CO2 Network Design for Washington DC/Baltimore

    NASA Astrophysics Data System (ADS)

    Lopez-Coto, I.; Prasad, K.; Ghosh, S.; Whetstone, J. R.

    2015-12-01

    The North-East Corridor project aims to use a top-down inversion method to quantify sources of Greenhouse Gas (GHG) emissions in the urban areas of Washington DC and Baltimore at approximately 1km2 resolutions. The aim of this project is to help establish reliable measurement methods for quantifying and validating GHG emissions independently of the inventory methods typically used to guide mitigation efforts. Since inversion methods depend on atmospheric observations of GHG, deploying a suitable network of ground-based measurement stations is a fundamental step in estimating emissions from the perspective of the atmosphere with reasonable levels of uncertainty. The purpose of this work is to design a tower based network of measurement stations that can reduce the uncertainty in emissions by 50% in the central areas of DC and Baltimore. To this end, the Weather Research and Forecasting Model (WRF-ARW) was used along with the Stochastic Time-Inverted Lagrangian Transport model (STILT) to derive the sensitivity of hypothetical observations to surface emissions (footprints) for the months of February and July 2013. An iterative selection algorithm, based on k-means clustering method, was applied in order to minimize the similarities between the temporal response of each site and maximize the urban contribution. Afterwards, a synthetic inversion Kalman Filter was used to evaluate the performances of the observing system based on the merit of the retrieval over time and the amount of a priori uncertainty reduced by the network. We present the performances of various measurement networks that consist of different number of towers and where the location of these towers vary. Results show that too compact networks lose spatial coverage whilst too spread networks lose capabilities of constraining uncertainties in the fluxes. In addition, we explore the possibility of using a very high density network of low-cost, low-accuracy sensors characterized by larger uncertainties and

  12. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... GENERAL GUIDELINES AND UNIFORM STANDARDS FOR URBAN PLANNING AND DESIGN OF DEVELOPMENT WITHIN THE PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington, DC... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Urban design of Washington,...

  13. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CORPORATION GENERAL GUIDELINES AND UNIFORM STANDARDS FOR URBAN PLANNING AND DESIGN OF DEVELOPMENT WITHIN THE PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington, DC... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Urban design of...

  14. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CORPORATION GENERAL GUIDELINES AND UNIFORM STANDARDS FOR URBAN PLANNING AND DESIGN OF DEVELOPMENT WITHIN THE PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington, DC... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Urban design of...

  15. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CORPORATION GENERAL GUIDELINES AND UNIFORM STANDARDS FOR URBAN PLANNING AND DESIGN OF DEVELOPMENT WITHIN THE PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington, DC... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Urban design of...

  16. 36 CFR 910.13 - Urban design of Washington, DC.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CORPORATION GENERAL GUIDELINES AND UNIFORM STANDARDS FOR URBAN PLANNING AND DESIGN OF DEVELOPMENT WITHIN THE PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.13 Urban design of Washington, DC... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Urban design of...

  17. Design and field performance of the KENETECH photovoltaic inverter system

    SciTech Connect

    Behnke, M.R.

    1995-11-01

    KENETECH Windpower has recently adapted the power conversion technology developed for the company`s variable speed wind turbine to grid-connected photovoltaic applications. KENETECH PV inverter systems are now in successful operation at the Sacramento Municipal Utility District`s (SMUD) Hedge Substation and the PVUSA-Davis site, with additional systems scheduled to be placed into service by the end of 1995 at SMUD, the New York Power Authority, Xerox Corporation`s Clean Air Now project, and the Georgia Tech Aquatic Center. The features of the inverter are described.

  18. Integrated Inverter And Battery Charger

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E.

    1988-01-01

    Circuit combines functions of dc-to-ac inversion (for driving ac motor in battery-powered vehicle) and ac-to-dc conversion (for charging battery from ac line when vehicle not in use). Automatically adapts to either mode. Design of integrated inverter/charger eliminates need for duplicate components, saves space, reduces weight and cost of vehicle. Advantages in other applications : load-leveling systems, standby ac power systems, and uninterruptible power supplies.

  19. Polarization-encoded all-optical quaternary universal inverter and design of multivalued flip-flop

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay; Roy, Jitendra Nath

    2010-03-01

    Quaternary inverters are the fundamental building blocks of multivalued flip-flops (MVFFs). A novel all-optical quaternary universal inverter circuit with the help of a semiconductor optical amplifier-assisted Sagnac switch is proposed and described. This circuit exploits the polarization properties of light. Different logical states are represented by different polarization states of light. A terahertz optical asymmetric multiplexer-based gate plays an important role here. Numerical simulation results confirming the described method are given. An all-optical circuit for a MVFF (quaternary) with the help of our proposed quaternary universal inverter is also designed, and simulation results are presented.

  20. 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.

  1. Design and construction evaluation of a photovoltaic DC LED lighting system

    NASA Astrophysics Data System (ADS)

    Bhamidipati, Jyotsna

    2008-08-01

    The market demand for commercialization of Photovoltaic (PV) systems depends a lot on the reliability, efficiency and performance of various components within the system. PV panels produce DC power when exposed to sunlight, and an inverter converts this to AC power in a typical solar powered building. Though, PV lighting has existed for a long time it hasn't been very effective, as incandescent light sources were commonly used which are inefficient. Today fluorescent fixtures are mostly used with PV's due to its high efficacy. Light-emitting diodes present a new vision to energy efficiency in lighting design with their low energy consumption. Current research predicts improved efficiencies of LED light fixtures and their commercial use is a few years away. LEDs which operate on DC voltages when coupled with photovoltaics can be a simple PV lighting application and a sustainable solution with potential for payback. This research evaluates the design and construction of a photovoltaic DC LED lighting system for a solar house at Pennsylvania State University. A detailed cost and payback analysis of a PV DC LED lighting system is presented in this research. PV output simulations for the solar house are presented. Results presented in this research indicate that the Solid state lighting market is evolving rapidly and that LED's are a choice in stand-alone photovoltaic DC lighting systems. The efficiency and the cost-effectiveness of such systems would however improve in the coming years with research and development now focused on PV systems and on Solid state lighting technologies.

  2. Design of piezoelectric transformer for DC/DC converter with stochastic optimization method

    NASA Astrophysics Data System (ADS)

    Vasic, Dejan; Vido, Lionel

    2016-04-01

    Piezoelectric transformers were adopted in recent year due to their many inherent advantages such as safety, no EMI problem, low housing profile, and high power density, etc. The characteristics of the piezoelectric transformers are well known when the load impedance is a pure resistor. However, when piezoelectric transformers are used in AC/DC or DC/DC converters, there are non-linear electronic circuits connected before and after the transformer. Consequently, the output load is variable and due to the output capacitance of the transformer the optimal working point change. This paper starts from modeling a piezoelectric transformer connected to a full wave rectifier in order to discuss the design constraints and configuration of the transformer. The optimization method adopted here use the MOPSO algorithm (Multiple Objective Particle Swarm Optimization). We start with the formulation of the objective function and constraints; then the results give different sizes of the transformer and the characteristics. In other word, this method is looking for a best size of the transformer for optimal efficiency condition that is suitable for variable load. Furthermore, the size and the efficiency are found to be a trade-off. This paper proposes the completed design procedure to find the minimum size of PT in need. The completed design procedure is discussed by a given specification. The PT derived from the proposed design procedure can guarantee both good efficiency and enough range for load variation.

  3. 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.

  4. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Osullivan, G.; Merrill, W. C.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. Optimization of the inverter/controller design is discussed as part of an overall photovoltaic power system designed for maximum energy extraction from the solar array. The special design requirements for the inverter/ controller include: a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy.

  5. Design of Energy Storage Reactors for Dc-To-Dc Converters. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Chen, D. Y.

    1975-01-01

    Two methodical approaches to the design of energy-storage reactors for a group of widely used dc-to-dc converters are presented. One of these approaches is based on a steady-state time-domain analysis of piecewise-linearized circuit models of the converters, while the other approach is based on an analysis of the same circuit models, but from an energy point of view. The design procedure developed from the first approach includes a search through a stored data file of magnetic core characteristics and results in a list of usable reactor designs which meet a particular converter's requirements. Because of the complexity of this procedure, a digital computer usually is used to implement the design algorithm. The second approach, based on a study of the storage and transfer of energy in the magnetic reactors, leads to a straightforward design procedure which can be implemented with hand calculations. An equation to determine the lower-bound volume of workable cores for given converter design specifications is derived. Using this computer lower-bound volume, a comparative evaluation of various converter configurations is presented.

  6. DESIGN OF A DC/RF PHOTOELECTRON GUN.

    SciTech Connect

    YU,D.NEWSHAM,Y.SMIRONOV,A.YU,J.SMEDLEY,J.SRINIVASAN RAU,T.LEWELLEN,J.ZHOLENTS,A.

    2003-05-12

    An integrated dc/rf photoelectron gun produces a low-emittance beam by first rapidly accelerating electrons at a high gradient during a short ({approx}1 ns), high-voltage pulse, and then injecting the electrons into an rf cavity for subsequent acceleration. Simulations show that significant improvement of the emittance appears when a high field ({approx} 0.5-1 GV/m) is applied to the cathode surface. An adjustable dc gap ({le} 1 mm) which can be integrated with an rf cavity is designed for initial testing at the Injector Test Stand at Argonne National Laboratory using an existing 70-kV pulse generator. Plans for additional experiments of an integrated dc/rf gun with a 250-kV pulse generator are being made.

  7. Control algorithm for the inverter fed induction motor drive with DC current feedback loop based on principles of the vector control

    SciTech Connect

    Vuckovic, V.; Vukosavic, S. )

    1992-01-01

    This paper brings out a control algorithm for VSI fed induction motor drives based on the converter DC link current feedback. It is shown that the speed and flux can be controlled over the wide speed and load range quite satisfactorily for simpler drives. The base commands of both the inverter voltage and frequency are proportional to the reference speed, but each of them is further modified by the signals derived from the DC current sensor. The algorithm is based on the equations well known from the vector control theory, and is aimed to obtain the constant rotor flux and proportionality between the electrical torque, the slip frequency and the active component of the stator current. In this way, the problems of slip compensation, Ri compensation and correction of U/f characteristics are solved in the same time. Analytical considerations and computer simulations of the proposed control structure are in close agreement with the experimental results measured on a prototype drive.

  8. 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.

  9. Optimal high speed CMOS inverter design using craziness based Particle Swarm Optimization Algorithm

    NASA Astrophysics Data System (ADS)

    De, Bishnu P.; Kar, Rajib; Mandal, Durbadal; Ghoshal, Sakti P.

    2015-07-01

    The inverter is the most fundamental logic gate that performs a Boolean operation on a single input variable. In this paper, an optimal design of CMOS inverter using an improved version of particle swarm optimization technique called Craziness based Particle Swarm Optimization (CRPSO) is proposed. CRPSO is very simple in concept, easy to implement and computationally efficient algorithm with two main advantages: it has fast, nearglobal convergence, and it uses nearly robust control parameters. The performance of PSO depends on its control parameters and may be influenced by premature convergence and stagnation problems. To overcome these problems the PSO algorithm has been modiffed to CRPSO in this paper and is used for CMOS inverter design. In birds' flocking or ffsh schooling, a bird or a ffsh often changes direction suddenly. In the proposed technique, the sudden change of velocity is modelled by a direction reversal factor associated with the previous velocity and a "craziness" velocity factor associated with another direction reversal factor. The second condition is introduced depending on a predeffned craziness probability to maintain the diversity of particles. The performance of CRPSO is compared with real code.gnetic algorithm (RGA), and conventional PSO reported in the recent literature. CRPSO based design results are also compared with the PSPICE based results. The simulation results show that the CRPSO is superior to the other algorithms for the examples considered and can be efficiently used for the CMOS inverter design.

  10. Developments in a methodology for the design of engineered invert traps in combined sewer systems.

    PubMed

    Buxton, A; Tait, S; Stovin, V; Saul, A

    2002-01-01

    Sediments within sewers can have a significant effect on the operation of the sewer system and on the surrounding natural and urban environment. One possible method for the management of sewer sediments is the use of slotted invert traps. Although invert traps can be used to selectively trap only inorganic bedload material, little is known with regard to the design of these structures. This paper presents results from a laboratory investigation comparing the trapping performance of three slot size configurations of a laboratory-scale invert trap. The paper also presents comparative results from a two-dimensional computational model utilising stochastic particle tracking. This investigation shows that particle tracking consistently over-predicts sediment retention efficiencies observed within the laboratory model. PMID:11989888

  11. Optimal brushless DC motor design using genetic algorithms

    NASA Astrophysics Data System (ADS)

    Rahideh, A.; Korakianitis, T.; Ruiz, P.; Keeble, T.; Rothman, M. T.

    2010-11-01

    This paper presents a method for the optimal design of a slotless permanent magnet brushless DC (BLDC) motor with surface mounted magnets using a genetic algorithm. Characteristics of the motor are expressed as functions of motor geometries. The objective function is a combination of losses, volume and cost to be minimized simultaneously. Electrical and mechanical requirements (i.e. voltage, torque and speed) and other limitations (e.g. upper and lower limits of the motor geometries) are cast into constraints of the optimization problem. One sample case is used to illustrate the design and optimization technique.

  12. An SCR inverter for electric vehicles

    NASA Technical Reports Server (NTRS)

    Latos, T.; Bosack, D.; Ehrlich, R.; Jahns, T.; Mezera, J.; Thimmesch, D.

    1980-01-01

    An inverter for an electric vehicle propulsion application has been designed and constructed to excite a polyphase induction motor from a fixed propulsion battery source. The inverter, rated at 35kW peak power, is fully regenerative and permits vehicle operation in both the forward and reverse directions. Thyristors are employed as the power switching devices arranged in a dc bus commutated topology. This paper describes the major role the controller plays in generating the motor excitation voltage and frequency to deliver performance similar to dc systems. Motoring efficiency test data for the controller are presented. It is concluded that an SCR inverter in conjunction with an ac induction motor is a viable alternative to present dc vehicle propulsion systems on the basis of performance and size criteria.

  13. Design and Performance of the Cornell ERL DC Photoemission Gun

    NASA Astrophysics Data System (ADS)

    Smolenski, K.; Bazarov, I.; Dunham, B.; Li, H.; Li, Y.; Liu, X.; Ouzounov, D.; Sinclair, C.

    2009-08-01

    Cornell University is planning to build an Energy Recovery Linac (ERL) X-ray facility. For an ERL, it is well known that the x-ray beam brightness for the users is mainly determined by the initial electron beam emittance provided by the injector. To address technical challenges of producing very low emittance beams at high average current as required for an ERL, Cornell University has proposed a prototype injector with 5-15 MeV beam energy, 100 mA maximum average current and 77 pC/bunch. In this article, we describe the design, construction and initial results for a DC photoemission gun now under operation.

  14. Cascade direct adaptive fuzzy control design for a nonlinear two-axis inverted-pendulum servomechanism.

    PubMed

    Wai, Rong-Jong; Kuo, Meng-An; Lee, Jeng-Dao

    2008-04-01

    This paper presents and analyzes a cascade direct adaptive fuzzy control (DAFC) scheme for a two-axis inverted-pendulum servomechanism. Because the dynamic characteristic of the two-axis inverted-pendulum servomechanism is a nonlinear unstable nonminimum-phase underactuated system, it is difficult to design a suitable control scheme that simultaneously realizes real-time stabilization and accurate tracking control, and it is not easy to directly apply conventional computed torque strategies to this underactuated system. Therefore, the cascade DAFC scheme including inner and outer control loops is investigated for the stabilizing and tracking control of a nonlinear two-axis inverted-pendulum servomechanism. The goal of the inner control loop is to design a DAFC law so that the stick angle vector can fit the stick angle command vector derived from the stick angle reference model. In the outer loop, the reference signal vector is designed via an adaptive path planner so that the cart position vector tracks the cart position command vector. Moreover, all adaptive algorithms in the cascade DAFC system are derived using the Lyapunov stability analysis, so that system stability can be guaranteed in the entire closed-loop system. Relying on this cascade structure, the stick angle and cart position tracking-error vectors will simultaneously converge to zero. Numerical simulations and experimental results are given to verify that the proposed cascade DAFC system can achieve favorable stabilizing and tracking performance and is robust with regard to system uncertainties. PMID:18348926

  15. A design procedure for the phase-controlled parallel-loaded resonant inverter

    NASA Technical Reports Server (NTRS)

    King, Roger J.

    1989-01-01

    High-frequency-link power conversion and distribution based on a resonant inverter (RI) has been recently proposed. The design of several topologies is reviewed, and a simple approximate design procedure is developed for the phase-controlled parallel-loaded RI. This design procedure seeks to ensure the benefits of resonant conversion and is verified by data from a laboratory 2.5 kVA, 20-kHz converter. A simple phasor analysis is introduced as a useful approximation for design purposes. The load is considered to be a linear impedance (or an ac current sink). The design procedure is verified using a 2.5-kVA 20-kHz RI. Also obtained are predictable worst-case ratings for each component of the resonant tank circuit and the inverter switches. For a given load VA requirement, below-resonance operation is found to result in a significantly lower tank VA requirement. Under transient conditions such as load short-circuit, a reversal of the expected commutation sequence is possible.

  16. Energy-Saving Inverter

    NASA Technical Reports Server (NTRS)

    Rippel, W. E.; Edwards, D. B.

    1984-01-01

    Commutation by field-effect transistor allows more efficient operation. High voltage field-effect transistor (FET) controls silicon controlled rectifiers (SCR's). Circuit requires only one capacitor and one inductor in commutation circuit: simpler, more efficient, and more economical than conventional inverters. Adaptable to dc-to-dc converters.

  17. Extending the Constant Power Speed Range of the Brushless DC Motor through Dual Mode Inverter Control -- Part II: Laboratory Proof-of-Principle

    SciTech Connect

    Lawler, J.S.

    2001-10-29

    Previous theoretical work has shown that when all loss mechanisms are neglected the constant power speed range (CPSR) of a brushless dc motor (BDCM) is infinite when the motor is driven by the dual-mode inverter control (DMIC) [1,2]. In a physical drive, losses, particularly speed-sensitive losses, will limit the CPSR to a finite value. In this paper we report the results of laboratory testing of a low-inductance, 7.5-hp BDCM driven by the DMIC. The speed rating of the test motor rotor limited the upper speed of the testing, and the results show that the CPSR of the test machine is greater than 6:1 when driven by the DMIC. Current wave shape, peak, and rms values remained controlled and within rating over the entire speed range. The laboratory measurements allowed the speed-sensitive losses to be quantified and incorporated into computer simulation models, which then accurately reproduce the results of lab testing. The simulator shows that the limiting CPSR of the test motor is 8:1. These results confirm that the DMIC is capable of driving low-inductance BDCMs over the wide CPSR that would be required in electric vehicle applications.

  18. PV Inverter Products Manufacturing and Design Improvements for Cost Reduction and Performance Enhancements: Final Subcontract Report, November 2003 (Revised)

    SciTech Connect

    West, R.

    2004-04-01

    The specific objectives of this subcontracted development work by Xantrex Technology Inc. were to: (1) Capture the newest digital signal processor (DSP) technology to create high-impact,''next generation'' power conversion equipment for the PV industry; (2) Create a common resource base for three PV product lines. This standardized approach to both hardware and software control platforms will provide significant market advantage over foreign competition; (3) Achieve cost reductions through increased volume of common components, reduced assembly labor, and the higher efficiency of producing more products with fewer design, manufacturing, and production test variations; (4) Increase PV inverter product reliability. Reduce inverter size, weight and conversion losses. The contract goals were to achieve an overall cost reduction of 10% to 20% for the three inverters and with no compromise in performance. The cost of the 10-kW inverter was reduced by 56%, and the cost of the 25-kW inverter was reduced by 53%. The 2.5-kW inverter has no basis for comparison, but should benefit equally from this design approach. Not only were the contract cost reduction goals exceeded by a wide margin, but the performance and reliability of the products were also enhanced. The conversion efficiency improvement, as reflected in the 50% conversion loss reduction, adds significant value in renewable energy applications. The size and weight reductions also add value by providing less cumbersome product solutions for system designers.

  19. Buckling Design Studies of Inverted, Oblate Bulkheads for a Propellant Tank

    NASA Technical Reports Server (NTRS)

    Smeltzer, Stanley S., III; Bowman, Lynn M.

    2002-01-01

    An investigation of the deformation and buckling characteristics of a composite, oblate bulkhead that has an inverted geometry and is subjected to pressure-only loading is presented for three bulkhead geometries and thicknesses. The effects of a stiffening support ring at the bulkhead to cylinder interface are also evaluated. Buckling analyses conducted using the axisymmetric shell code BOSOR4 are discussed for several bulkhead configurations. These results are analytically verified using results from the Structural Analysis of General Shells (STAGS) code for a selected bulkhead configuration. The buckling characterization of an inverted, oblate bulkhead requires careful attention as small changes in bulkhead parameters can have a significant effect on the critical buckling load. Comparison of BOSOR4 and STAGS results provided a very good correlation between the two analysis methods. In addition, the analysis code BOSOR4 was found to be an efficient sizing tool that is useful during the preliminary design stage of a practical shell structure. Together, these two aspects should give the design engineer confidence in sizing these stability critical structures. Additional characterization is warranted, especially for a composite tank structure, since only one bulkhead configuration was examined closely.

  20. Design and Quasi-Equilibrium Analysis of a Distributed Frequency-Restoration Controller for Inverter-Based Microgrids

    SciTech Connect

    Ainsworth, Nathan G; Grijalva, Prof. Santiago

    2013-01-01

    This paper discusses a proposed frequency restoration controller which operates as an outer loop to frequency droop for voltage-source inverters. By quasi-equilibrium analysis, we show that the proposed controller is able to provide arbitrarily small steady-state frequency error while maintaing power sharing between inverters without need for communication or centralized control. We derive rate of convergence, discuss design considerations (including a fundamental trade-off that must be made in design), present a design procedure to meet a maximum frequency error requirement, and show simulation results verifying our analysis and design method. The proposed controller will allow flexible plug-and-play inverter-based networks to meet a specified maximum frequency error requirement.

  1. Design of a DC Busbar for the ITER PF Converter

    NASA Astrophysics Data System (ADS)

    Guo, Bin; Song, Zhiquan; Xu, Liuwei; Zhang, Ming; Li, Jinchao; Jiang, Li; Fu, Peng; Wang, Min; Dong, Lin

    2014-04-01

    The DC busbar is an important component for the ITER PF converter module to connect the converter and the reactor. This paper analyzes different cross-sections and different thermodynamic properties under natural-cooling and water-cooling conditions, and simulation is carried out by the software of the finite element method (FEM). The result of the analysis shows that the water-cooling method is the better choice for the DC busbar.

  2. 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.

  3. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Merrill, W. C.; Osullivan, G.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. This paper discusses the optimization of the inverter/controller design as part of an overall Photovoltaic Power System (PPS) designed for maximum energy extraction from the solar array. The special design requirements for the inverter/controller include: (1) a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and (2) an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy. It must be capable of operating connected to the utility line at a level set by an external controller (PSC).

  4. Stepped sinewave inverter

    NASA Astrophysics Data System (ADS)

    Appelbaum, J.; Gabbay, D.

    1984-11-01

    A stepped sinewave dc/ac inverter was analyzed for an inductive load with respect to load current and voltage, harmonics, power factor, and efficiency. This special inverter of high efficiency and low harmonic content is constructed by synthesizing the sinusoidal output by discrete voltage sources, such as storage batteries, solar cell, etc., with electronic switching of the sources at specific time intervals. The switching times are determined for the condition of minimum distortion of the synthesized wave. A 50 W inverter was built and tested to demonstrate this approach.

  5. Three-phase inverter for small high speed motors

    NASA Astrophysics Data System (ADS)

    McCormick, John A.; Valenzuela, Javier A.

    1991-07-01

    A high-frequency three-phase inverter is being developed to drive a miniature centrifugal compressor which is a key component in a long-life space-borne cryocooler. The inverter is a unique transformer-coupled design, tailored to the low-voltage high-current characteristic of the compressor's induction motor. The design and performance demonstration of a breadboard model of the inverter are described. The cryocooler uses a reverse-Brayton cycle with turbomachines to provide 5 watt of cooling at 70 K. The design target for input power to the compressor motor is 175 watts. Line-to-neutral phase voltage waveforms to be supplied by the inverter have an amplitude of 15 volt-rms at a frequency of 8 kHz. DC power at 28 volt is supplied to the inverter. The breadboard inverter was tested with a preliminary development model of the compressor. It drove the compressor over a range of operating conditions encompassing frequencies of 5 to 9 kHz at powers of 56 to 437 watt. Inverter efficiencies, calculated from experimentally verified loss models, ranged from 89 to 95 percent over the tests. The design target on efficiency is 90 percent. The inverter was demonstrated to supply starting current adequate to overcome the starting friction of the compressor's self-acting gas bearings by a safe margin.

  6. Three-phase inverter for small high speed motors

    NASA Technical Reports Server (NTRS)

    Mccormick, John A.; Valenzuela, Javier A.

    1991-01-01

    A high-frequency three-phase inverter is being developed to drive a miniature centrifugal compressor which is a key component in a long-life space-borne cryocooler. The inverter is a unique transformer-coupled design, tailored to the low-voltage high-current characteristic of the compressor's induction motor. The design and performance demonstration of a breadboard model of the inverter are described. The cryocooler uses a reverse-Brayton cycle with turbomachines to provide 5 watt of cooling at 70 K. The design target for input power to the compressor motor is 175 watts. Line-to-neutral phase voltage waveforms to be supplied by the inverter have an amplitude of 15 volt-rms at a frequency of 8 kHz. DC power at 28 volt is supplied to the inverter. The breadboard inverter was tested with a preliminary development model of the compressor. It drove the compressor over a range of operating conditions encompassing frequencies of 5 to 9 kHz at powers of 56 to 437 watt. Inverter efficiencies, calculated from experimentally verified loss models, ranged from 89 to 95 percent over the tests. The design target on efficiency is 90 percent. The inverter was demonstrated to supply starting current adequate to overcome the starting friction of the compressor's self-acting gas bearings by a safe margin.

  7. 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.

  8. Design and Analysis of the Main AC/DC Converter System for ITER

    NASA Astrophysics Data System (ADS)

    Sheng, Zhicai; Xu, Liuwei; Fu, Peng

    2012-04-01

    A design of the main AC/DC converter system for ITER is described and the configuration of the main AC/DC converters is presented. To reduce the reactive power absorbed from the converter units, the main AC/DC converters are designed to be series-connected and work in a sequential mode. The structure of the regulator of the converter system is described. A simulation model was built up for the PSCAD/EMTDC code, and the design was validated accordingly. Harmonic analysis and reactive power calculation of the converters units are presented. The results reveal the advantage of sequential control in reducing reactive power and harmonics.

  9. Design of An Inverted Magnetron Gun for a High Power Gyroklystron

    NASA Astrophysics Data System (ADS)

    Read, Michael E.; Nusinovich, Gregory; Ives, R. Lawrence

    2003-12-01

    A magnetron injection gun (MIG) with an inverted geometry is described. Use of an inverted geometry with the inner electrode at ground potential provides support for the inner coax portion of the cavities of a high power gyroklystron, and results in improved optics. The geometry of the gun is described and results of trajectory simulations are presented.

  10. R2R-printed inverted OPV modules - towards arbitrary patterned designs

    NASA Astrophysics Data System (ADS)

    Välimäki, M.; Apilo, P.; Po, R.; Jansson, E.; Bernardi, A.; Ylikunnari, M.; Vilkman, M.; Corso, G.; Puustinen, J.; Tuominen, J.; Hast, J.

    2015-05-01

    We describe the fabrication of roll-to-roll (R2R) printed organic photovoltaic (OPV) modules using gravure printing and rotary screen-printing processes. These two-dimensional printing techniques are differentiating factors from coated OPVs enabling the direct patterning of arbitrarily shaped and sized features into visual shapes and, increasing the freedom to connect the cells in modules. The inverted OPV structures comprise five layers that are either printed or patterned in an R2R printing process. We examined the rheological properties of the inks used and their relationship with the printability, the compatibility between the processed inks, and the morphology of the R2R-printed layers. We also evaluate the dimensional accuracy of the printed pattern, which is an important consideration in designing arbitrarily-shaped OPV structures. The photoactive layer and top electrode exhibited excellent cross-dimensional accuracy corresponding to the designed width. The transparent electron transport layer extended 300 µm beyond the designed values, whereas the hole transport layer shrank 100 µm. We also examined the repeatability of the R2R fabrication process when the active area of the module varied from 32.2 cm2 to 96.5 cm2. A thorough layer-by-layer optimization of the R2R printing processes resulted in realization of R2R-printed 96.5 cm2 sized modules with a maximum power conversion efficiency of 2.1% (mean 1.8%) processed with high functionality.

  11. Integral inverter/battery charger for use in electric vehicles

    NASA Technical Reports Server (NTRS)

    Thimmesch, D.

    1983-01-01

    The design and test results of a thyristor based inverter/charger are discussed. A battery charger is included integral to the inverter by using a subset of the inverter power circuit components. The resulting charger provides electrical isolation between the vehicle propulsion battery and ac line and is capable of charging a 25 kWh propulsion battery in 8 hours from a 220 volt ac line. The integral charger employs the inverter commutation components at a resonant ac/dc isolated converter rated at 3.6 kW. Charger efficiency and power factor at an output power of 3.6 kW are 86% and 95% respectively. The inverter, when operated with a matching polyphase ac induction motor and nominal 132 volt propulsion battery, can provide a peak shaft power of 34 kW (45 ph) during motoring operation and 45 kW (60 hp) during regeneration. Thyristors are employed for the inverter power switching devices and are arranged in an input-commutated topology. This configuration requires only two thyristors to commutate the six main inverter thyristors. Inverter efficiency during motoring operation at motor shaft speeds above 450 rad/sec (4300 rpm) is 92-94% for output power levels above 11 KW (15 hp). The combined ac inverter/charger package weighs 47 kg (103 lbs).

  12. User's design handbook for a Standardized Control Module (SCM) for DC to DC Converters, volume 2

    NASA Technical Reports Server (NTRS)

    Lee, F. C.

    1980-01-01

    A unified design procedure is presented for selecting the key SCM control parameters for an arbitrarily given power stage configuration and parameter values, such that all regulator performance specifications can be met and optimized concurrently in a single design attempt. All key results and performance indices, for buck, boost, and buck/boost switching regulators which are relevant to SCM design considerations are included to facilitate frequent references.

  13. Advanced Modular Inverter Technology Development

    SciTech Connect

    Adam Szczepanek

    2006-02-04

    Electric and hybrid-electric vehicle systems require an inverter to convert the direct current (DC) output of the energy generation/storage system (engine, fuel cells, or batteries) to the alternating current (AC) that vehicle propulsion motors use. Vehicle support systems, such as lights and air conditioning, also use the inverter AC output. Distributed energy systems require an inverter to provide the high quality AC output that energy system customers demand. Today's inverters are expensive due to the cost of the power electronics components, and system designers must also tailor the inverter for individual applications. Thus, the benefits of mass production are not available, resulting in high initial procurement costs as well as high inverter maintenance and repair costs. Electricore, Inc. (www.electricore.org) a public good 501 (c) (3) not-for-profit advanced technology development consortium assembled a highly qualified team consisting of AeroVironment Inc. (www.aerovironment.com) and Delphi Automotive Systems LLC (Delphi), (www.delphi.com), as equal tiered technical leads, to develop an advanced, modular construction, inverter packaging technology that will offer a 30% cost reduction over conventional designs adding to the development of energy conversion technologies for crosscutting applications in the building, industry, transportation, and utility sectors. The proposed inverter allows for a reduction of weight and size of power electronics in the above-mentioned sectors and is scalable over the range of 15 to 500kW. The main objective of this program was to optimize existing AeroVironment inverter technology to improve power density, reliability and producibility as well as develop new topology to reduce line filter size. The newly developed inverter design will be used in automotive and distribution generation applications. In the first part of this program the high-density power stages were redesigned, optimized and fabricated. One of the main tasks

  14. Design and analysis of inverted H shape dual band patch antenna for microwave application

    NASA Astrophysics Data System (ADS)

    Ullah, M. Habib; Islam, M. T.; Mandeep, J. S.; Misran, N.; Reaz, M. B. I.

    2013-04-01

    Design and analysis of an inverted H shape printed dual band patch antenna has been presented in this paper. The proposed antenna has designed by 3-D full wave high frequency electromagnetic simulator HFSS and printed in low cost, durable epoxy polymer resin composite material substrate. The printed antenna prototype has been measured in a standard far field anechoic electromagnetic field measurement chamber. The measured results have analyzed by using computer aided plotting tool OriginPro 8.5. Measured -10 dB return loss bandwidth 3.25 GHz from 9.75 GHz to 13 GHz with peak gain 8.5 dBi have been achieved. The proposed antenna has obtained 0.63 dBi gain with 96% efficiency at lower band 10.3 GHz and 6.03 dBi gain with 84.2% efficiency at upper band 12.5 GHz. The almost steady radiation pattern makes the proposed antenna appropriate for part of X and Ku band applications. Moreover, the input impedance and current distribution along the radiating patch of the proposed antenna have also been analyzed in this paper.

  15. Decoupled Control Strategy of Grid Interactive Inverter System with Optimal LCL Filter Design

    NASA Astrophysics Data System (ADS)

    Babu, B. Chitti; Anurag, Anup; Sowmya, Tontepu; Marandi, Debati; Bal, Satarupa

    2013-09-01

    This article presents a control strategy for a three-phase grid interactive voltage source inverter that links a renewable energy source to the utility grid through a LCL-type filter. An optimized LCL-type filter has been designed and modeled so as to reduce the current harmonics in the grid, considering the conduction and switching losses at constant modulation index (Ma). The control strategy adopted here decouples the active and reactive power loops, thus achieving desirable performance with independent control of active and reactive power injected into the grid. The startup transients can also be controlled by the implementation of this proposed control strategy: in addition to this, optimal LCL filter with lesser conduction and switching copper losses as well as core losses. A trade-off has been made between the total losses in the LCL filter and the Total Harmonic Distortion (THD%) of the grid current, and the filter inductor has been designed accordingly. In order to study the dynamic performance of the system and to confirm the analytical results, the models are simulated in the MATLAB/Simulink environment, and the results are analyzed.

  16. Product design for energy reduction in concurrent engineering: An Inverted Pyramid Approach

    NASA Astrophysics Data System (ADS)

    Alkadi, Nasr M.

    on product, process, and system design parameters. In depth evaluation to how the design and manufacturing normally happen in concurrent engineering provided a framework to develop energy system levels in machining within the concurrent engineering environment using the method of "Inverted Pyramid Approach", (IPA). The IPA features varying levels of output energy based information depending on the input design parameters that is available during each stage (level) of the product design. The experimental work, the in-depth evaluation of design and manufacturing in CE, and the developed energy system levels in machining provided a solid base for the development of the model for the design for energy reduction in CE. The model was used to analyze an example part where 12 evolving designs were thoroughly reviewed to investigate the sensitivity of energy to design parameters in machining. The model allowed product design teams to address manufacturing energy concerns early during the design stage. As a result, ranges for energy sensitive design parameters impacting product manufacturing energy consumption were found in earlier levels. As designer proceeds to deeper levels in the model, this range tightens and results in significant energy reductions.

  17. Design of Current Source Dc/Dc Converter for Interfacing a 5 Kw Pem Fuel Cell / Paaugstinošā Strāvas Avota Līdzsprieguma Pārveidotāja Izstrāde 5 Kw Ūdeņraža Degvielas Elementam

    NASA Astrophysics Data System (ADS)

    Andreičiks, A.; Steiks, I.; Krievs, O.

    2013-08-01

    In domestic applications the low DC output voltage of a hydrogen fuel cell used as the main power supply or a backup power source has to be matched to the level and frequency of the AC voltage of utility grid. The interfacing power converter system usually consists of a DC/DC converter and an inverter. In this work, a DC/DC step-up converter stage is designed for interfacing a 5kW proton exchange membrane (PEM) fuel cell. The losses of DC/DC conversion are estimated and, basing on the relevant analysis, the most appropriate configuration of converter modules is selected for a DC/DC converter stage of increased efficiency. The authors present the results of experimental analysis and simulation for the selected configuration of four double inductor step-up push-pull converter modules Ūdeņraža degvielas elementa invertoru sistēmas mājsaimniecības pielietojumiem parasti sastāv no līdzsprieguma paaugstināšanas un invertēšanas mezgliem. Šis raksts ir veltīts paaugstinošā līdzsprieguma pārveidotāja izstrādei 5 kW protonu apmaiņas membrānas degvielas elementam. Rakstā izpētīts divu induktoru divtaktu strāvas avota paaugstinošais līdzsprieguma pārveidotājs, aplūkojot gan datormodelēšanas, gan eksperimentālos rezultātus. Lai palielinātu DC/DC pārveidotāja efektivitāti var izmantot vairākus pārveidotāja moduļus, kam ieejas savienotas paralēli un izejās - virkne. Analīze Šajā raksta ir veikta analīze, balstoties uz kuras var izvēlieties skaitu pārveidotāj moduļu skaitu, kuri nodrošina vislabāko efektivitāti DC/DC pārveidotāja posmā. Kopējais eksperimentāli noteiktais izstrādātās degvielas elementa pārveidotāju sistēmas fizikālā modeļa lietderības koeficients ir 93%

  18. Inverting the Linear Algebra Classroom

    ERIC Educational Resources Information Center

    Talbert, Robert

    2014-01-01

    The inverted classroom is a course design model in which students' initial contact with new information takes place outside of class meetings, and students spend class time on high-level sense-making activities. The inverted classroom model is so called because it inverts or "flips" the usual classroom design where typically class…

  19. Applications of cascade multilevel inverters.

    PubMed

    Peng, Fang-zen; Qian, Zhao-ming

    2003-01-01

    Cascade multilevel inverters have been developed for electric utility applications. A cascade M-level inverter consists of (M-1)/2 H-bridges in which each bridge's dc voltage is supported by its own dc capacitor. The new inverter can: (1) generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle; (2) dispense with multi-pulse inverters' transformers used in conventional utility interfaces and static var compensators; (3) enables direct parallel or series transformer-less connection to medium- and high-voltage power systems. In short, the cascade inverter is much more efficient and suitable for utility applications than traditional multi-pulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for power supply, (hybrid) electric vehicle (EV) motor drive, reactive power (var) and harmonic compensation. This paper summarizes the features, feasibility, and control schemes of the cascade inverter for utility applications including utility interface of renewable energy, voltage regulation, var compensation, and harmonic filtering in power systems. Analytical, simulated, and experimental results demonstrated the superiority of the new inverters. PMID:14566981

  20. Effective switching frequency multiplier inverter

    SciTech Connect

    Su, Gui-Jia; Peng, Fang Z.

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  1. Analysis and design of DSP-based dual-loop controlled UPS inverters.

    PubMed

    Wu, Xie-Hua; Yan, Chao

    2003-01-01

    This paper presents a novel digital dual-loop control scheme of the PWM (Pulse width modulate) inverter. Deadbeat control technique are employed to enhance the performance. Half switching period delayed sampling and control tining strategy is used to improve the system dynamic response. Simulation and experimental results presented in the paper verified the validity of the proposed control scheme. PMID:12765279

  2. 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

  3. Resonant snubber inverter

    DOEpatents

    Lai, J.S.; Young, R.W. Sr.; Chen, D.; Scudiere, M.B.; Ott, G.W. Jr.; White, C.P.; McKeever, J.W.

    1997-06-24

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 14 figs.

  4. Resonant snubber inverter

    DOEpatents

    Lai, Jih-Sheng; Young, Sr., Robert W.; Chen, Daoshen; Scudiere, Matthew B.; Ott, Jr., George W.; White, Clifford P.; McKeever, John W.

    1997-01-01

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  5. 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., Jr.; Wilson, T. G.

    1979-01-01

    The proposed dc model for bipolar junction power switching transistors is based on measurements which may be made with standard laboratory equipment. Those nonlinearities which are of importance to power electronics design are emphasized. Measurements procedures are discussed in detail. A model formulation adapted for use with a computer program is presented, and a comparison between actual and computer-generated results is made.

  6. 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.

  7. Design of mine-used DC carrier telephone based on STM32

    NASA Astrophysics Data System (ADS)

    Chen, Goufan; Zhou, Hui; Zhan, Minhua; Wang, Jian

    2016-01-01

    Abide by the design principles of mine intrinsically safe circuit, according to the need of underground communication in coal mine, the paper proposed a design scheme of DC carrier telephone which can dial. The design circuit of the telephone is introduced in detail. The telephone's voice signals are generated by the microphone. After enlarged then the voice signals are modulated to frequency signals by LM567 chip. The frequency signals are coupled by transformer and then transmitted by 12V DC power supply line to the other voice terminals. In the voice terminal the signals are demodulated by LM567 demodulation circuit and enlarged by LM386, then, the amplified audio signals are output from a speaker. The dialing circuit is designed based on the STM32 MCU. The dial information is transmitted to the other telephone terminals by CAN bus. The measured distance calls is greater than 2000m, volume is larger than 85dB, good results.

  8. Design of Dual band Modified Inverted F-Antenna for Military and Intelligent Transportation System (ITS) Applications by Numerical Analysis

    NASA Astrophysics Data System (ADS)

    Hossain, Robiul; Karmokar, Debabrata Kumar

    2012-11-01

    A design of single feed Dual Band Modified Inverted F-Antenna (IFA) operating at 4.45 GHz (4.4-4.7GHz) and 5.9 GHz (5.850-5.925 GHz) has been proposed in this paper. The design is initiated by trial and error method of Numerical Analysis and method of moments (MoMís) in Numerical Electromagnetic code (NEC) is used to design, simulate and analyze this antenna. The results exhibit a proper operation of the antenna in terms of return loss, bandwidth, efficiency, VSWR, and gain at both bands. Proposed antenna is designed to achieve multi-serving purposes. Military applications and applications in the Intelligent Transportation Systems (ITS) are the most important applications within the above mentioned frequency bands respectively. The simulated results including performance parameters of antenna are presented and all are acceptable for the standard antennas.

  9. 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.

  10. Class 1E dc power subsystem design description: 4 x 350 MW(t) Modular HTGR [High-Temperature Gas-Cooled Reactor] Plant

    SciTech Connect

    1986-06-01

    The Class 1E DC Power System of the Electrical Group provides reliable and regulated 125 V dc electric power to the plant safety-related dc loads connected to the Four redundant and independent 125 V dc Class 1E buses to ensure plant safe shutdown or mitigate the effects of a design basis event. These four dc buses comprise the plant four Class 1E dc control and instrument channels (A, B, C and D).

  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. Approaches to Suppressing Shaft Voltage in Brushless DC Motor Driven by PWM Inverter Based on Ungrounded Common-Mode Equivalent Circuit

    NASA Astrophysics Data System (ADS)

    Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo

    This paper describes an ungrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was is small, the reversal of the polarities of the common-mode voltage and shaft voltage is observed. In order to model this reversal, a bridge-type equivalent circuit is proposed. On the basis of calculations and experiment, it is found the values and polarity of the shaft voltage can be are accurately determined with the proposed equivalent circuit. Furthermore, the capacitance value of the insulated rotor required to make the shaft voltage equal to or less than the dielectric breakdown voltage of the bearing grease is obtained.

  13. Fault-tolerant three-level inverter

    DOEpatents

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

    2006-12-05

    A method for driving a neutral point clamped three-level inverter is provided. In one exemplary embodiment, DC current is received at a neutral point-clamped three-level inverter. The inverter has a plurality of nodes including first, second and third output nodes. The inverter also has a plurality of switches. Faults are checked for in the inverter and predetermined switches are automatically activated responsive to a detected fault such that three-phase electrical power is provided at the output nodes.

  14. Design and Testing of D.C. Conduction Pump for Sodium Cooled Fast Reactor

    SciTech Connect

    Nashine, B.K.; Dash, S.K.; Gurumurthy, K.; Rajan, M.; Vaidyanathan, G.

    2006-07-01

    DC Conduction pump immersed in sodium forms a part of Failed Fuel Location Module (FFLM) of 500 MWe Fast Breeder Reactor (PFBR) currently under construction. FFLM housed in control plug of the reactor, is used to locate the failed fuel sub-assembly due to clad rupture in the fuel pin. The DC conduction pump sucks the sodium from the top of fuel sub-assemblies through the selector valve and pumps the sodium to hold up for detecting the presence of delayed neutrons. Presence of delayed neutron is the indication of failure in the sampled fuel sub-assembly. The DC Conduction Pump was chosen because of its low voltage operation (2 V) where argon/alumina ceramic can provide required electrical insulation even at operating temperature of 560 deg. C without much complication on the manufacturing front. Sampling of sodium from top of different sub-assemblies is achieved by operation of selector valve in-conjunction with the drive motor. FFLM requires the pump to be immersed in sodium pool at {approx} 560 deg. C located above the fuel sub-assemblies in the reactor. The Pump of 0.36 m{sup 3}/h capacity and developing 1.45 Kg/ cm{sup 2} pressure was designed, manufactured and tested. The DC Conduction Pump has a stainless steel duct filled with liquid sodium, which is to be pumped. The stainless steel duct is kept in magnetic field obtained by means of electromagnet. The electromagnet is made of soft iron and the coil made of copper conductor surrounds the yoke portion of electromagnet. The external DC source of 2000 Amps, 2 Volt is used to send current through sodium placed in the stainless steel duct and the same current is sent through copper coil of electromagnet for producing required magneto motive force, which in turn produces required magnetic field. The interaction of current in sodium (placed in stainless steel duct) and magnetic field produced by the electromagnet in the duct region produces pumping force in the sodium. Electromagnet, copper coil, stainless steel

  15. Device characterization for design optimization of 4 junction inverted metamorphic concentrator solar cells

    SciTech Connect

    Geisz, John F.; France, Ryan M.; Steiner, Myles A.; Friedman, Daniel J.; García, Iván

    2014-09-26

    Quantitative electroluminescence (EL) and luminescent coupling (LC) analysis, along with more conventional characterization techniques, are combined to completely characterize the subcell JV curves within a fourjunction (4J) inverted metamorphic solar cell (IMM). The 4J performance under arbitrary spectral conditions can be predicted from these subcell JV curves. The internal radiative efficiency (IRE) of each junction has been determined as a function of current density from the external radiative efficiency using optical modeling, but this required the accurate determination of the individual junction current densities during the EL measurement as affected by LC. These measurement and analysis techniques can be applied to any multijunction solar cell. The 4J IMM solar cell used to illustrate these techniques showed excellent junction quality as exhibited by high IRE and a one-sun AM1.5D efficiency of 36.3%. This device operates up to 1000 suns without limitations due to any of the three tunnel junctions.

  16. Description of the control system design for the SSF PMAD DC testbed

    NASA Technical Reports Server (NTRS)

    Baez, Anastacio N.; Kimnach, Greg L.

    1991-01-01

    The Power Management and Distribution (PMAD) DC Testbed Control System for Space Station Freedom was developed using a top down approach based on classical control system and conventional terrestrial power utilities design techniques. The design methodology includes the development of a testbed operating concept. This operating concept describes the operation of the testbed under all possible scenarios. A unique set of operating states was identified and a description of each state, along with state transitions, was generated. Each state is represented by a unique set of attributes and constraints, and its description reflects the degree of system security within which the power system is operating. Using the testbed operating states description, a functional design for the control system was developed. This functional design consists of a functional outline, a text description, and a logical flowchart for all the major control system functions. Described here are the control system design techniques, various control system functions, and the status of the design and implementation.

  17. 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.

  18. A multilevel approach to the design of dc-free line codes

    NASA Technical Reports Server (NTRS)

    Calderbank, A. R.; Herro, Mark A.; Telang, Vivek

    1989-01-01

    A multilevel approach to the design of dc-free line codes is presented. The different levels can be used for different purposes; for example, to control the maximum accumulated charge or to guarantee a certain minimum distance. The advantages of codes designed by this method over similar codes are the improved run-length/accumulated-charge parameters, higher transmission rate, and the systematic nature of the code construction. The multilevel structure allows the redundancy in the signal selection procedure to be allocated efficiently among the different levels. It also allows the use of suboptimal staged decoding procedures that have performance/complexity advantages over maximum-likelihood decoding.

  19. Inverter ratio failure detector

    NASA Technical Reports Server (NTRS)

    Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (Inventor)

    1974-01-01

    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

  20. Nanowire NMOS Logic Inverter Characterization.

    PubMed

    Hashim, Yasir

    2016-06-01

    This study is the first to demonstrate characteristics optimization of nanowire N-Channel Metal Oxide Semiconductor (NW-MOS) logic inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. A computer-based model used to produce static characteristics of NW-NMOS logic inverter. In this research two circuit configuration of NW-NMOS inverter was studied, in first NW-NMOS circuit, the noise margin for (low input-high output) condition was very low. For second NMOS circuit gives excellent noise margins, and results indicate that optimization depends on applied voltage to the inverter. Increasing gate to source voltage with (2/1) nanowires ratio results better noise margins. Increasing of applied DC load transistor voltage tends to increasing in decreasing noise margins; decreasing this voltage will improve noise margins significantly. PMID:27427653

  1. Three dimensional finite element methods: Their role in the design of DC accelerator systems

    SciTech Connect

    Podaru, Nicolae C.; Gottdang, A.; Mous, D. J. W.

    2013-04-19

    High Voltage Engineering has designed, built and tested a 2 MV dual irradiation system that will be applied for radiation damage studies and ion beam material modification. The system consists of two independent accelerators which support simultaneous proton and electron irradiation (energy range 100 keV - 2 MeV) of target sizes of up to 300 Multiplication-Sign 300 mm{sup 2}. Three dimensional finite element methods were used in the design of various parts of the system. The electrostatic solver was used to quantify essential parameters of the solid-state power supply generating the DC high voltage. The magnetostatic solver and ray tracing were used to optimize the electron/ion beam transport. Close agreement between design and measurements of the accelerator characteristics as well as beam performance indicate the usefulness of three dimensional finite element methods during accelerator system design.

  2. Three dimensional finite element methods: Their role in the design of DC accelerator systems

    NASA Astrophysics Data System (ADS)

    Podaru, Nicolae C.; Gottdang, A.; Mous, D. J. W.

    2013-04-01

    High Voltage Engineering has designed, built and tested a 2 MV dual irradiation system that will be applied for radiation damage studies and ion beam material modification. The system consists of two independent accelerators which support simultaneous proton and electron irradiation (energy range 100 keV - 2 MeV) of target sizes of up to 300 × 300 mm2. Three dimensional finite element methods were used in the design of various parts of the system. The electrostatic solver was used to quantify essential parameters of the solid-state power supply generating the DC high voltage. The magnetostatic solver and ray tracing were used to optimize the electron/ion beam transport. Close agreement between design and measurements of the accelerator characteristics as well as beam performance indicate the usefulness of three dimensional finite element methods during accelerator system design.

  3. Intrinsic Hardware Evolution for the Design and Reconfiguration of Analog Speed Controllers for a DC Motor

    NASA Technical Reports Server (NTRS)

    Gwaltney, David A.; Ferguson, Michael I.

    2003-01-01

    Evolvable hardware provides the capability to evolve analog circuits to produce amplifier and filter functions. Conventional analog controller designs employ these same functions. Analog controllers for the control of the shaft speed of a DC motor are evolved on an evolvable hardware platform utilizing a second generation Field Programmable Transistor Array (FPTA2). The performance of an evolved controller is compared to that of a conventional proportional-integral (PI) controller. It is shown that hardware evolution is able to create a compact design that provides good performance, while using considerably less functional electronic components than the conventional design. Additionally, the use of hardware evolution to provide fault tolerance by reconfiguring the design is explored. Experimental results are presented showing that significant recovery of capability can be made in the face of damaging induced faults.

  4. Genetic algorithm based design optimization of a permanent magnet brushless dc motor

    NASA Astrophysics Data System (ADS)

    Upadhyay, P. R.; Rajagopal, K. R.

    2005-05-01

    Genetic algorithm (GA) based design optimization of a permanent magnet brushless dc motor is presented in this paper. A 70 W, 350 rpm, ceiling fan motor with radial-filed configuration is designed by considering the efficiency as the objective function. Temperature-rise and motor weight are the constraints and the slot electric loading, magnet-fraction, slot-fraction, airgap, and airgap flux density are the design variables. The efficiency and the phase-inductance of the motor designed using the developed CAD program are improved by using the GA based optimization technique; from 84.75% and 5.55 mH to 86.06% and 2.4 mH, respectively.

  5. Fuzzy Auto-adjust PID Controller Design of Brushless DC Motor

    NASA Astrophysics Data System (ADS)

    Yuanxi, Wang; Yali, Yu; Guosheng, Zhang; Xiaoliang, Sheng

    Using conventional PID control method, to guarantee the rapidity and small overshoot dynamic and static performance of the BLDCM (brushless DC motor) system is out of the question. The control method to combine fuzzy control with PID control was fit the multivariable strong coupling nonlinear characteristic of BLDCM system. Matlab/Simulink simulation model had been built. The result of computer simulation shows that, compared with the conventional PID controller, the dynamic and static performance of fuzzy auto-adjust PID controller are put forward to optimize. The research work of this paper has profound significance for high precision controller design.

  6. Simulations for preliminary design of a multi-cathode DC electron gun for eRHIC

    SciTech Connect

    Wu, Q.; Ben-Zvi, I.; Chang, X.; Skaritka, J.

    2010-05-23

    The proposed electron ion collider, eRHIC, requires a large average polarized electron current of 50 mA, which is more than 20 times higher than the present experimental output of a single, highly polarized electron source, based on cesiated super-lattice GaAs. To meet eRHIC's requirement for current, we designed a multicathode DC electron gun for injection. The twenty-four GaAs cathodes emit electrons in sequence, then are combined on axis by a rotating field (or 'funnelled'). In addition to its ultra-high vacuum requirements, the multicathode DC electron gun will place high demand on the electric field symmetry, the magnetic field shielding, and on preventing arcing. In this paper, we discuss our results from a 3D simulation of the latest model for this gun. The findings will guide the actual design in future. Their preliminary design of a multi-cathode electron source for eRHIC demonstrated tolerable fields and reasonable results in both field and particle simulations.

  7. Experimental study of a bidirectional DC-DC converter for the DC link voltage control and the regenerative braking in PM motor drives devoted to electrical vehicles

    SciTech Connect

    Caricchi, F.; Crescimbini, F.; Noia, G.; Pirolo, D.

    1994-12-31

    The use of a bidirectional DC-DC converter operating in the DC link of CRPWM-inverter-fed motor drives devoted to electric vehicles (EVs) application allows a suitable control of both motoring and regenerative braking operations, and it can contribute to a significant increase of the motor drive overall efficiency. This paper deals with the experimental study of a bidirectional DC-DC converter prototype which has been designed for application in small-size EVs propelled by axial-flux PM motor drives. The paper discusses the converter modes of operation and reports the experimental results taken from a converter prototype which has been constructed using an IGBTs power module rated 600 V, 50 A. 2 refs.

  8. Integrated Inverter For Driving Multiple Electric Machines

    DOEpatents

    Su, Gui-Jia [Knoxville, TN; Hsu, John S [Oak Ridge, TN

    2006-04-04

    An electric machine drive (50) has a plurality of inverters (50a, 50b) for controlling respective electric machines (57, 62), which may include a three-phase main traction machine (57) and two-phase accessory machines (62) in a hybrid or electric vehicle. The drive (50) has a common control section (53, 54) for controlling the plurality of inverters (50a, 50b) with only one microelectronic processor (54) for controlling the plurality of inverters (50a, 50b), only one gate driver circuit (53) for controlling conduction of semiconductor switches (S1-S10) in the plurality of inverters (50a, 50b), and also includes a common dc bus (70), a common dc bus filtering capacitor (C1) and a common dc bus voltage sensor (67). The electric machines (57, 62) may be synchronous machines, induction machines, or PM machines and may be operated in a motoring mode or a generating mode.

  9. DC CICC retrofit magnet preliminary design, software development and analysis report

    SciTech Connect

    Myatt, R.L.; Marston, P.G.

    1992-02-10

    The proposed retrofit coil is made of superconducting Cable-in-Conduit Conductor (CICC). The coils are designed to produce a nominal vertical field of 4.5 tesla within the MHD channel based on a nominal current density of 13.05 MA/m{sup 2}. The coils are supported within a case, or so-called constant tension strap. When the magnet is energized, the electromagnetic J {times} B body forces push the winding pack laterally outward and vertically towards the machine's midplane, thus putting the strap in tension. The end turns add axial tension to the conductor (a condition which is not simulated by this 2-D model of the midlength cross section). A sketch of the magnet system and structure is shown in Fig. 1.0-1. The purpose of this report is to describe the progress made in the design and analysis of the DC CICC retrofit magnet, and to outline the proposed next step.

  10. DC CICC retrofit magnet preliminary design, software development and analysis report. Quarterly progress report

    SciTech Connect

    Myatt, R.L.; Marston, P.G.

    1992-01-01

    The proposed retrofit coil is made of superconducting Cable-in-Conduit Conductor (CICC). The coils are designed to produce a nominal vertical field of 4.5 tesla within the MHD channel based on a nominal current density of 13.05 MA/m{sup 2}. The coils are supported within a case, or so-called constant tension strap. When the magnet is energized, the electromagnetic J x B body forces push the winding pack laterally outward and vertically towards the machine`s midplane, thus putting the strap in tension. The end turns add axial tension to the conductor (a condition which is not simulated by this 2-D model of the midlength cross section). A sketch of the magnet system and structure is shown in Fig. 1.0--1. The purpose of this report is to describe the progress made in the design and analysis of the DC CICC retrofit magnet.

  11. Design, construction and testing of a DC bioeffects test enclosure for small animals. Final report

    SciTech Connect

    Frazier, M J; Preache, M M

    1980-11-01

    This final report describes both the engineering development of a DC bioeffects test enclosure for small laboratory animals, and the biological protocol for the use of such enclosures in the testing of animals to determine possible biological effects of the environment associated with HVDC transmission lines. The test enclosure which has been designed is a modular unit, which will house up to eight rat-sized animals in individual compartments. Multiple test enclosures can be used to test larger numbers of animals. A prototype test enclosure has been fabricated and tested to characterize its electrical performance characteristics. The test enclosure provides a simulation of the dominant environment associated with HVDC transmission lines; namely, a static electric field and an ion current density. A biological experimental design has been developed for assessing the effects of the dominant components of the HVDC transmission line environment.

  12. Variable-frequency inverter controls torque, speed, and braking in ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1974-01-01

    Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

  13. Improved DC Gun and Insulator Assembly

    SciTech Connect

    Neubauer, Michael; Johnson, Rolland P

    2015-01-11

    Many user facilities such as synchrotron radiation light sources and free electron lasers rely on DC high voltage photoguns with internal field gradients as high as 10 to 15 MV/m. These high gradients often lead to field emission which poses serious problems for the photocathode used to generate the electron beam and the ceramic insulators used to bias the photocathode at high voltage. Ceramic insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic causing a buildup of charge and eventual puncture, and also because large diameter ceramics are difficult to braze reliably. The lifetimes of photo cathodes inside high current DC guns exhibiting field emission are limited to less than a hundred hours. Reducing the surface gradients on the metals reduces the field emission, which serves to maintain the required ultrahigh vacuum condition. A novel gun design with gradients around 5 MV/m and operating at 350 kV, a major improvement over existing designs, was proposed that allows for the in-situ replacement of photo cathodes in axially symmetric designs using inverted ceramics. In this project, the existing JLAB CEBAF asymmetric gun design with an inverted ceramic support was modeled and the beam dynamics characterized. An improved structure was designed that reduces the surface gradients and improves the beam optics. To minimize the surface gradients, a number of electrostatic gun designs were studied to determine the optimum configuration of the critical electrodes within the gun structure. Coating experiments were carried out to create a charge dissipative coating for cylindrical ceramics. The phase II proposal, which was not granted, included the design and fabrication of an axially symmetric DC Gun with an inverted ceramic that would operate with less than 5 MV/m at 350 kV and would be designed with an in-situ replaceable photo-cathode.

  14. Microgrid and Inverter Control and Simulator Software

    SciTech Connect

    2012-09-13

    A collection of software that can simulate the operation of an inverter on a microgrid or control a real inverter. In addition, it can simulate the control of multiple nodes on a microgrid." Application: Simulation of inverters and microgrids; control of inverters on microgrids." The MMI submodule is designed to control custom inverter hardware, and to simulate that hardware. The INVERTER submodule is only the simulator code, and is of an earlier generation than the simulator in MMI. The MICROGRID submodule is an agent-based simulator of multiple nodes on a microgrid which presents a web interface. The WIND submodule produces movies of wind data with a web interface.

  15. Electronically commutated dc motors for electric vehicles

    NASA Technical Reports Server (NTRS)

    Maslowski, E. A.

    1981-01-01

    A motor development program to explore the feasibility of electronically commutated dc motors (also known as brushless) for electric cars is described. Two different design concepts and a number of design variations based on these concepts are discussed. One design concept is based on a permanent magnet, medium speed, machine rated at 7000 to 9000 rpm, and powered via a transistor inverter power conditioner. The other concept is based on a permanent magnet, high speed, machine rated at 22,000 to 26,000 rpm, and powered via a thyristor inverter power conditioner. Test results are presented for a medium speed motor and a high speed motor each of which have been fabricated using samarium cobalt permanent magnet material.

  16. Step-by-Step Design of an FPGA-Based Digital Compensator for DC/DC Converters Oriented to an Introductory Course

    ERIC Educational Resources Information Center

    Zumel, P.; Fernandez, C.; Sanz, M.; Lazaro, A.; Barrado, A.

    2011-01-01

    In this paper, a short introductory course to introduce field-programmable gate array (FPGA)-based digital control of dc/dc switching power converters is presented. Digital control based on specific hardware has been at the leading edge of low-medium power dc/dc switching converters in recent years. Besides industry's interest in this topic, from…

  17. Magnet design and beam dynamics in computed fields for the DC-350 cyclotron

    NASA Astrophysics Data System (ADS)

    Kazarinov, N. Yu.; Sazonov, M. N.

    2008-12-01

    The DC-350 is an isochronous cyclotron designed in the Flerov Laboratory of Nuclear Reaction (FLNR). It is intended for accelerating ions with a mass-to-charge ratio A/Z within an interval of 5-10 and with an energy of 3-12 MeV/u at the extraction radius. These ion beams will be used in nuclear and applied physics experiments. The paper describes the results of a 3D magnet simulation. The cyclotron magnet and IM90 analiziting-bend magnet of the axial injection channel are studied here. The influence of correction coils on the cyclotron magnet is calculated. All magnet fields were calculated by MERMAID 3D code [1].

  18. Effect of design variables on irreversible magnet demagnetization in brushless dc motor

    NASA Astrophysics Data System (ADS)

    Kim, Tae Heoung; Lee, Ju

    2005-05-01

    The large demagnetizing currents in brushless dc (BLdc) motor are generated by the short-circuited stator windings and the fault of a drive circuit. So, irreversible magnet demagnetization occurs due to the external demagnetizing field by these currents. In this paper, we deal with the effect of design variables on irreversible magnet demagnetization in BLdc motor through the modeling approach using a two-dimensional finite-element method (2D FEM). The nonlinear analysis of a permanent magnet is added to 2D FEM to consider irreversible demagnetization. As a result, it is shown that magnet thickness, teeth surface width, and rotor back yoke thickness are the most important geometrical dimensions of BLdc motor in terms of irreversible magnet demagnetization.

  19. DC-9 flight demonstration program with refanned JT8D engines. Volume 2: Design and construction

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The nacelle configuration selected for the DC-9 had a 1595.6 mm Refan length inlet and an 1811.8 mm exhaust duct. The inlet had 1234.4 mm of acoustic treatment and the tailpipe had 1305.5 mm of equivalent length acoustic treatment. The pylon was reduced in width from 425.5 mm to 204.5 mm. Fuselage frames and titanium skin panels in the area of the pylon were reinforced or replaced to support the higher loads and engine thrust. Experimental type tooling, fabrication and assembly were used on all hardware. The design is considered certifiable and representative of the hardware that would be built as retrofit kits.

  20. Advanced composite rudders for DC-10 aircraft: Design, manufacturing, and ground tests

    NASA Technical Reports Server (NTRS)

    Lehman, G. M.; Purdy, D. M.; Cominsky, A.; Hawley, A. V.; Amason, M. P.; Kung, J. T.; Palmer, R. J.; Purves, N. B.; Marra, P. J.; Hancock, G. R.

    1976-01-01

    Design synthesis, tooling and process development, manufacturing, and ground testing of a graphite epoxy rudder for the DC-10 commercial transport are discussed. The composite structure was fabricated using a unique processing method in which the thermal expansion characteristics of rubber tooling mandrels were used to generate curing pressures during an oven cure cycle. The ground test program resulted in certification of the rudder for passenger-carrying flights. Results of the structural and environmental tests are interpreted and detailed development of the rubber tooling and manufacturing process is described. Processing, tooling, and manufacturing problems encountered during fabrication of four development rudders and ten flight-service rudders are discussed and the results of corrective actions are described. Non-recurring and recurring manufacturing labor man-hours are tabulated at the detailed operation level. A weight reduction of 13.58 kg (33 percent) was attained in the composite rudder.

  1. Design of a dc SQUID Phase Qubit with Controlled Coupling to the Microwave Signal

    NASA Astrophysics Data System (ADS)

    Budoyo, R. P.; Przybysz, A. J.; Cooper, B. K.; Kwon, H.; Kim, Z.; Cheng, B.; Dragt, A. J.; Anderson, J. R.; Lobb, C. J.; Wellstood, F. C.; Khalil, M.; Gladchenko, S.; Stoutimore, M.; Palmer, B. S.; Osborn, K. D.

    2011-03-01

    We have designed an Al/ Al Ox /Al dc SQUID phase qubit on a sapphire substrate with a qubit junction area of 0.3 μ m 2 to minimize loss associated with two-level systems in the junction oxide barrier. The qubit junction is shunted with a 1.5 pF interdigitated capacitor, and is isolated from the bias leads by an LC filter and an inductive isolation network using a larger Josephson junction. A previous device we built with similar parameters had its relaxation time T1 limited by coupling to the microwave line. To reduce this coupling, we adopted a transmission line design and verified the coupling strength using microwave simulations. The new design will also allow us to measure the coupling to the SQUID by throughput measurements. We will discuss our design, the microwave simulations, our estimates for the overall coherence time due to losses and noise from various sources, and our progress towards testing the device. Acknowledgement: DOD, JQI, and CNAM.

  2. 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

  3. Nonlinear analysis of a family of LC tuned inverters

    NASA Technical Reports Server (NTRS)

    Lee, F. C. Y.; Wilson, T. G.

    1975-01-01

    Four widely used self-oscillating dc-to-square-wave parallel inverters which employ an inductor-capacitor tuned network to determine the oscillation frequency are reduced to a common equivalent RLC network, The techniques of singular-point analysis and state-plane interpretations are employed to describe the steady-state and transient behavior of these circuits and to elucidate the three possible modes of operation: quasi-harmonic, relaxation, and discontinuous. Design guidelines are provided through a study of the influence of circuit parameter variations on the characteristics of oscillation and on frequency stability. Several examples are provided to illustrate the usefulness of this analysis when studying such problems as transistor emitter-to-base junction breakdown during oscillations and the design of starting circuits to insure self-excited oscillations in these inverters.

  4. Evaluation of recent residential inverters

    SciTech Connect

    Nichols, B.E.

    1982-06-01

    Seven residential utility-interactive inverters for photovoltaic power systems have been evaluated at MIT Laboratory and at the Northeast Residential Experiment Station (NE RES). Two, a Windworks Gemini and an Abacus Sunverter, have been reported on previously. Reviewed here are five other inverters: Windworks Gemini 8-kW (dc) model with an ac filter to improve the output current waveform and power factor; Acheval Wind Electronics 10-kW (ac) model, Helionetics 6-kW (dc) model; and American Power Conversion 2-kW and 4-kW (ac) models. Input and output power, power factor, current waveform distortion, audio noise and radio frequency interference measurements were made at the NE RES and the results are presented.

  5. Design of single-winding energy-storage reactors for dc-to-dc converters using air-gapped magnetic-core structures

    NASA Technical Reports Server (NTRS)

    Ohri, A. K.; Wilson, T. G.; Owen, H. A., Jr.

    1977-01-01

    A procedure is presented for designing air-gapped energy-storage reactors for nine different dc-to-dc converters resulting from combinations of three single-winding power stages for voltage stepup, current stepup and voltage stepup/current stepup and three controllers with control laws that impose constant-frequency, constant transistor on-time and constant transistor off-time operation. The analysis, based on the energy-transfer requirement of the reactor, leads to a simple relationship for the required minimum volume of the air gap. Determination of this minimum air gap volume then permits the selection of either an air gap or a cross-sectional core area. Having picked one parameter, the minimum value of the other immediately leads to selection of the physical magnetic structure. Other analytically derived equations are used to obtain values for the required turns, the inductance, and the maximum rms winding current. The design procedure is applicable to a wide range of magnetic material characteristics and physical configurations for the air-gapped magnetic structure.

  6. A unified analysis and design procedure for a standardized control module for dc-dc switching regulators

    NASA Technical Reports Server (NTRS)

    Lee, F. C.; Yu, Y.; Mahmoud, M. F.

    1980-01-01

    Three basic switching regulators: buck, boost, and buck/boost, employing a multi-loop control module (SCM) were characterized by a common small signal block diagram. Employing the unified model, regulator performances such as stability, audiosusceptibility, output impedance and step load transient are analyzed and key performance indexes are expressed in simple analytical forms. More importantly, the performance characteristics of all three regulators are shown to enjoy common properties due to the unique SCM control scheme which nullifies the positive zero and provides adaptive compensation to the moving poles of the boost and buck/boost converters. This allows a simple unified design procedure to be devised for selecting the key SCM control parameters for an arbitrarily given power stage configuration and parameter values, such that all regulator performance specifications can be met and optimized concurrently in a single design attempt.

  7. DC CICC retrofit magnet preliminary design, software development and analysis report. Quarterly progress report, January 1992

    SciTech Connect

    Myatt, R.L.; Marston, P.G.

    1992-02-10

    The proposed retrofit coil is made of superconducting Cable-in-Conduit Conductor (CICC). The coils are designed to produce a nominal vertical field of 4.5 tesla within the MHD channel based on a nominal current density of 13.05 MA/m{sup 2}. The coils are supported within a case, or so-called constant tension strap. When the magnet is energized, the electromagnetic J {times} B body forces push the winding pack laterally outward and vertically towards the machine`s midplane, thus putting the strap in tension. The end turns add axial tension to the conductor (a condition which is not simulated by this 2-D model of the midlength cross section). A sketch of the magnet system and structure is shown in Fig. 1.0-1. The purpose of this report is to describe the progress made in the design and analysis of the DC CICC retrofit magnet, and to outline the proposed next step.

  8. Stream, Inverted

    NASA Technical Reports Server (NTRS)

    2006-01-01

    27 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the inverted, eroded remains of a channel -- now standing as a complex ridge that runs across the middle of this scene -- in dust-mantled terrain west of Sinus Meridiani, Mars. The original channel might have been carved by running water, but too little detail remains today to provide any certainty as to whether water was the culprit.

    Location near: 5.6oN, 7.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Northern Spring

  9. Power inverters

    SciTech Connect

    Miller, David H.; Korich, Mark D.; Smith, Gregory S.

    2011-11-15

    Power inverters include a frame and a power module. The frame has a sidewall including an opening and defining a fluid passageway. The power module is coupled to the frame over the opening and includes a substrate, die, and an encasement. The substrate includes a first side, a second side, a center, an outer periphery, and an outer edge, and the first side of the substrate comprises a first outer layer including a metal material. The die are positioned in the substrate center and are coupled to the substrate first side. The encasement is molded over the outer periphery on the substrate first side, the substrate second side, and the substrate outer edge and around the die. The encasement, coupled to the substrate, forms a seal with the metal material. The second side of the substrate is positioned to directly contact a fluid flowing through the fluid passageway.

  10. A Standalone Solar Photovoltaic Power Generation using Cuk Converter and Single Phase Inverter

    NASA Astrophysics Data System (ADS)

    Verma, A. K.; Singh, B.; Kaushika, S. C.

    2013-03-01

    In this paper, a standalone solar photovoltaic (SPV) power generating system is designed and modeled using a Cuk dc-dc converter and a single phase voltage source inverter (VSI). In this system, a dc-dc boost converter boosts a low voltage of a PV array to charge a battery at 24 V using a maximum power point tracking control algorithm. To step up a 24 V battery voltage to 360 V dc, a high frequency transformer based isolated dc-dc Cuk converter is used to reduce size, weight and losses. The dc voltage of 360 V is fed to a single phase VSI with unipolar switching to achieve a 230 Vrms, 50 Hz ac. The main objectives of this investigation are on efficiency improvement, reduction in cost, weight and size of the system and to provide an uninterruptible power to remotely located consumers. The complete SPV system is designed and it is modeled in MATLAB/Simulink. The simulated results are presented to demonstrate its satisfactory performance for validating the proposed design and control algorithm.

  11. Inverter Output Filter Effect on PWM Motor Drives of a Flywheel Energy Storage System

    NASA Technical Reports Server (NTRS)

    Santiago, Walter

    2004-01-01

    NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheel systems for small satellite energy storage and attitude control applications. One research and development area has been the minimization of the switching noise produced by the pulsed width modulated (PWM) inverter that drives the flywheel permanent magnet motor/generator (PM M/G). This noise can interfere with the flywheel M/G hardware and the system avionics hampering the full speed performance of the flywheel system. One way to attenuate the inverter switching noise is by placing an AC filter at the three phase output terminals of the inverter with the filter neutral point connected to the DC link (DC bus) midpoint capacitors. The main benefit of using an AC filter in this fashion is the significant reduction of the inverter s high dv/dt switching and its harmonics components. Additionally, common mode (CM) and differential mode (DM) voltages caused by the inverter s high dv/dt switching are also reduced. Several topologies of AC filters have been implemented and compared. One AC filter topology consists of a two-stage R-L-C low pass filter. The other topology consists of the same two-stage R-L-C low pass filter with a series connected trap filter (an inductor and capacitor connected in parallel). This paper presents the analysis, design and experimental results of these AC filter topologies and the comparison between the no filter case and conventional AC filter.

  12. Design and development of DC high current sensor using Hall-Effect method

    NASA Astrophysics Data System (ADS)

    Dewi, Sasti Dwi Tungga; Panatarani, C.; Joni, I. Made

    2016-02-01

    This paper report a newly developed high DC current sensor by using a Hall effect method and also the measurement system. The Hall effect sensor receive the magnetic field generated by a current carrying conductor wire. The SS49E (Honeywell) magnetoresistive sensor was employed to sense the magnetic field from the field concentrator. The voltage received from SS49E then converted into digital by using analog to digital converter (ADC-10 bit). The digital data then processed in the microcontroller to be displayed as the value of the electric current in the LCD display. In addition the measurement was interfaced into Personal Computer (PC) using the communication protocols of RS232 which was finally displayed in real-time graphical form on the PC display. The performance test on the range ± 40 Ampere showed that the maximum relative error is 5.26%. It is concluded that the sensors and the measurement system worked properly according to the design with acceptable accuracy.

  13. Design and control of the phase current of a brushless dc motor to eliminate cogging torque

    NASA Astrophysics Data System (ADS)

    Jang, G. H.; Lee, C. J.

    2006-04-01

    This paper presents a design and control method of the phase current to reduce the torque ripple of a brushless dc (BLDC) motor by eliminating cogging torque. The cogging torque is the main source of torque ripple and consequently of speed error, and it is also the excitation source to generate the vibration and noise of a motor. This research proposes a modified current wave form, which is composed of main and auxiliary currents. The former is the conventional current to generate the commutating torque. The latter generates the torque with the same magnitude and opposite sign of the corresponding cogging torque at the given position in order to eliminate the cogging torque. Time-stepping finite element method simulation considering pulse-width-modulation switching method has been performed to verify the effectiveness of the proposed method, and it shows that this proposed method reduces torque ripple by 36%. A digital-signal-processor-based controller is also developed to implement the proposed method, and it shows that this proposed method reduces the speed ripple significantly.

  14. Multiple high voltage output DC-to-DC power converter

    NASA Technical Reports Server (NTRS)

    Cronin, Donald L. (Inventor); Farber, Bertrand F. (Inventor); Gehm, Hartmut K. (Inventor); Goldin, Daniel S. (Inventor)

    1977-01-01

    Disclosed is a multiple output DC-to-DC converter. The DC input power is filtered and passed through a chopper preregulator. The chopper output is then passed through a current source inverter controlled by a squarewave generator. The resultant AC is passed through the primary winding of a transformer, with high voltages induced in a plurality of secondary windings. The high voltage secondary outputs are each solid-state rectified for passage to individual output loads. Multiple feedback loops control the operation of the chopper preregulator, one being responsive to the current through the primary winding and another responsive to the DC voltage level at a selected output.

  15. Dual Mode Inverter Control Test Verification

    SciTech Connect

    Bailey, J.M.

    2001-04-25

    Permanent Magnet Motors with either sinusoidal back emf (permanent magnet synchronous motor [PMSM]) or trapezoidal back emf (brushless dc motor [BDCM]) do not have the ability to alter the air gap flux density (field weakening). Since the back emf increases with speed, the system must be designed to operate with the voltage obtained at its highest speed. Oak Ridge National Laboratory's (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) has developed a dual mode inverter controller (DMIC) that overcomes this disadvantage. This report summarizes the results of tests to verify its operation. The standard PEEMRC 75 kW hard-switched inverter was modified to implement the field weakening procedure (silicon controlled rectifier enabled phase advance). A 49.5 hp motor rated at 2800 rpm was derated to a base of 400 rpm and 7.5 hp. The load developed by a Kahn Industries hydraulic dynamometer, was measured with a MCRT9-02TS Himmelstein and Company torque meter. At the base conditions a current of 212 amperes produced the 7.5 hp. Tests were run at 400, 1215, and 2424 rpm. In each run, the current was no greater than 214 amperes. The horsepower obtained in the three runs were 7.5, 9.3, and 8.12. These results verified the basic operation of the DMIC in producing a Constant Power Speed Ratios (CPSR) of six.

  16. Pulse width modulation inverter with battery charger

    NASA Technical Reports Server (NTRS)

    Slicker, James M. (Inventor)

    1985-01-01

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

  17. Pulse width modulation inverter with battery charger

    DOEpatents

    Slicker, James M.

    1985-01-01

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

  18. Design and wind tunnel tests of winglets on a DC-10 wing

    NASA Technical Reports Server (NTRS)

    Gilkey, R. D.

    1979-01-01

    Results are presented of a wind tunnel test utilizing a 4.7 percent scale semi-span model in the Langley Research Center 8-foot transonic pressure wind tunnel to establish the cruise drag improvement potential of winglets as applied to the DC-10 wide body transport aircraft. Winglets were investigated on both the DC-10 Series 10 (domestic) and 30/40 (intercontinental) configurations and compared with the Series 30/40 configuration. The results of the investigation confirm that for the DC-10 winglets provide approximately twice the cruise drag reduction of wing-tip extensions for about the same increase in bending moment at the wing fuselage juncture. Furthermore, the winglet configurations achieved drag improvements which were in close agreement to analytical estimates. It was observed that relatively small changes in wing-winglet tailoring effected large improvements in drag and visual flow characteristics. All final winglet configurations exhibited visual flow characteristics on the wing and winglets

  19. Design of direct drive robot using indigenously developed d.c. torque motors

    NASA Astrophysics Data System (ADS)

    Athani, Vithal V.

    The range of high-performance torque motors, which were indigenously developed for use in multistage satellite launch vehicles, is described. The main features that set dc torque motors apart from dc servomotors are: high peak torque, power, and current over short periods of operation, low speed of operation, obviating the need for gearing, high torque/inertia and torque/weight ratios, and high figure of merit = torque/sq rt watt ratio. The dc torque motors are eminently suited to high-performance applications requiring high torque at low speed of operation, such as aircraft and missile control surface actuation, control of multistage satellite launch vehicles, certain computer peripherals like magnetic tape transports and hard disk drives, and robotics, CNC systems, and machine tool control.

  20. High Power Factor Control Regulating Inverter Output Power in IPM Motor Driven by Inverter System without Electrolytic Capacitor

    NASA Astrophysics Data System (ADS)

    Inazuma, Kazuya; Ohishi, Kiyoshi; Haga, Hitoshi; Sazawa, Mataki; Kondo, Seiji

    This paper presents a new high power factor control method for a single-to-three-phase power converter without an electrolytic capacitor. The circuit used in the method consists of a single-phase rectifier, a small film capacitor at DC-link, a voltage-source three-phase inverter, and an IPM motor. The inverter regulates both the velocity of the IPM motor and input current waveform. In order to obtain a power factor of unity, we propose a new control method that regulates the inverter output power. The inverter output power controller is placed between the speed controller and the q-axis current controller. The inverter power is regulated by a PI and repetitive controller. When repetitive control is applied to the inverter power controller, the phase delay of the inverter power controller is quite small. The superior performance of the proposed method is demonstrated by experimental results.

  1. One-Cycle Controlled Single Phase UPS Inverter

    NASA Astrophysics Data System (ADS)

    Xiangli, Li; Hanhong, Qi

    A one-cycle controlled single-phase full-bridge DC-AC inverter is proposed. One-cycle control is a nonlinear control method which has fast transient response and good tracking performance. The one-cycle control immunizes the inverter against the perturbation of input dc bus and provides well system dynamic regulation with hybrid sinusoidal PWM control. The basic operational theory and control method are discussed in this paper. Finally, simulation waveforms and experimental results are given. The simulation and experimental results demonstrate the effectiveness of this control technique for inverters in UPS applications, especially when nonlinear loads must to be supplied and line has large undesirable harmonic components.

  2. Design of a robust modulation controller over a wide range of load characteristics for ac/dc systems

    SciTech Connect

    Choudry, M.A.; Reza, M.A. . Dept. of Electrical Engineering); Ellithy, K.A. )

    1990-02-01

    This paper presents a method to design a robust modulation controller to improve the dynamic performance of ac/dc systems. Static load is modeled as a nonlinear function of load bus voltage and dynamic load is modeled by an equivalent induction motor. Reactive power and dc power are considered for the modulation control. Static var compensator (SVC) is used for the reactive power modulation. The rotor speed and angle deviations of the synchronous generator are used as a stabilizing signal to the SVC. The controller gains are selected based on the eigenvalue sensitivity of electromechanical mode of the closed loop system with respect to load characteristic. Eigenvalue analysis and simulation results show that the proposed reactive power modulation control improves the system response over a wide range of voltage dependent load characteristic as compared with the control using only the rotor speed deviation.

  3. Design and realization of assessment software for DC-bias of transformers

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Liu, Lian-guang; Yuan, Zhong-chen

    2013-03-01

    The transformer working at the rated state will partically be saturated, and its mangetic current will be distorted accompanying with various of harmonic, increasing reactive power demand and some other affilicated phenomenon, which will threaten the safe operation of power grid. This paper establishes a transformer saturation circuit model of DCbias under duality principle basing on J-A theory which can reflect the hysteresis characteristics of iron core, and develops an software can assess the effects of transformer DC-bias using hybrid programming technology of C#.net and MATLAB with the microsoft.net platform. This software is able to simulate the mangnetizing current of different structures and assess the Saturation Level of transformers and the influnces of affilicated phenomenon accroding to the parameter of transformers and the DC equivalent voltage. It provides an effective method to assess the influnces of transformers caused by magnetic storm disaster and the earthing current of the HVDC project.

  4. Zero Voltage Soft Switching Duty Cycle Pulse Modulated High Frequency Inverter-Fed

    NASA Astrophysics Data System (ADS)

    Ishitobi, Manabu; Matsushige, Takayuki; Nakaoka, Mutsuo; Bessyo, Daisuke; Omori, Hideki; Terai, Haruo

    The utility grid voltage of commercial AC power source in Japan and USA is 100V, but in other Asian and European countries, it is 220V. In recent years, in Japan 200V outputted single-phase three-wire system begins to be used for high power applications. In 100V utility AC power applications and systems, an active voltage clamped quasi-resonant inverter circuit topology sing IGBTs has been effectively used so far for the consumer microwave oven. In this paper, presented is a half bridge type voltage-clamped asymmetrical soft switching PWM high-frequency inverter type AC-DC converter using IGBTs which is designed for consumer magnetron drive used as the consumer microwave oven in 200V utility AC power system. The zero voltage soft switching inverter treated here can use the same power rated switching semiconductor devices and three-winding high frequency transformer as those of the active voltage clamped quasi-resonant inverter using the IGBTs that has already been used for 100V utility AC power source. The operating performances of the voltage source single ended push pull (SEPP) type soft switching PWM inverter are evaluated and discussed for 100V and 200V common use consumer microwave oven. The harmonic line current components in the utility AC power side of the AC-DC power converter with ZVS-PWM SEPP inverter are reduced and improved on the basis of sine wave like pulse frequency modulation and sine wave like pulse width modulation for the utility AC voltage source.

  5. Microgrid and Inverter Control and Simulator Software

    Energy Science and Technology Software Center (ESTSC)

    2012-09-13

    A collection of software that can simulate the operation of an inverter on a microgrid or control a real inverter. In addition, it can simulate the control of multiple nodes on a microgrid." Application: Simulation of inverters and microgrids; control of inverters on microgrids." The MMI submodule is designed to control custom inverter hardware, and to simulate that hardware. The INVERTER submodule is only the simulator code, and is of an earlier generation than themore » simulator in MMI. The MICROGRID submodule is an agent-based simulator of multiple nodes on a microgrid which presents a web interface. The WIND submodule produces movies of wind data with a web interface.« less

  6. An Analytical Design Method for a Regenerative Braking Control System for DC-electrified Railway Systems under Light Load Conditions

    NASA Astrophysics Data System (ADS)

    Saito, Tatsuhito; Kondo, Keiichiro; Koseki, Takafumi

    A DC-electrified railway system that is fed by diode rectifiers at a substation is unable to return the electric power to an AC grid. Accordingly, the braking cars have to restrict regenerative braking power when the power consumption of the powering cars is not sufficient. However, the characteristics of a DC-electrified railway system, including the powering cars, is not known, and a mathematical model for designing a controller has not been established yet. Hence, the object of this study is to obtain the mathematical model for an analytical design method of the regenerative braking control system. In the first part of this paper, the static characteristics of this system are presented to show the position of the equilibrium point. The linearization of this system at the equilibrium point is then performed to describe the dynamic characteristics of the system. An analytical design method is then proposed on the basis of these characteristics. The proposed design method is verified by experimental tests with a 1kW class miniature model, and numerical simulations.

  7. ELECTROSTATIC MODELING OF THE JEFFERSON LABORATORY INVERTED CERAMIC GUN

    SciTech Connect

    P. Evtushenko ,F.E. Hannon, C. Hernandez-Garcia

    2010-05-01

    Jefferson Laboratory (JLab) is currently developing a new 500kV DC electron gun for future use with the FEL. The design consists of two inverted ceramics which support a central cathode electrode. This layout allows for a load-lock system to be located behind the gun chamber. The electrostatic geometry of the gun has been designed to minimize surface electric field gradients and also to provide some transverse focusing to the electron beam during transit between the cathode and anode. This paper discusses the electrode design philosophy and presents the results of electrostatic simulations. The electric field information obtained through modeling was used with particle tracking codes to predict the effects on the electron beam.

  8. Design and characterization of the DC acceleration and transport system required for the FOM 1 MW free electron maser experiment

    SciTech Connect

    Caplan, M.; Urbanus, W.H.; Geer, C. van der

    1995-12-31

    A Free Electron Maser (FEM) has been constructed and is soon to be tested at the FOM Institute (Rijnhuizen) Netherlands with the goal of producing 1 MW long pulse to CW microwave output in the range 130 GHz to 250 GHz. The design uses a DC beam system in a depressed collector configuration in order to make the overall wall plug efficiency 50%. The high voltage ({approximately} 2 MeV) power supply provides only the body interception current ({approximately} 30 mA) while the 12 amp beam current is supplied by the 100-200 keV collector supplies. Some of the design features to ensure low interception current, which is critical to long pulse (CW) operation are: (1) DC beam in-line transport and acceleration system, (2) emittance conserving solenoid focusing system, (3) halo suppression techniques at cathode edge, and (4) very low beam fill factor (<20%). A relativistic version of the Herman Optical theory developed for microwave tubes is used to determine current distribution functions everywhere along the beam from the electron gun, through the DC accelerator and transport system to the wiggler. This theory takes into account thermals far out on the gaussian tail which translates into beam current far outside the ideal beam edge. This theory is applied to the FOM beam line design to predict a series of beam envelope contours containing various percentages of total beam current up to 99.9%. Predictions of body interception current due to finite emittance (effective temperature) are presented and compared with measured experimental results.

  9. Run-Curve Design for Energy Saving Operation in a Modern DC-Electrification

    NASA Astrophysics Data System (ADS)

    Koseki, Takafumi; Noda, Takashi

    Mechanical brakes are often used by electric trains. These brakes have a few problems like response speed, coefficient of friction, maintenance cost and so on. As a result, methods for actively using regenerative brakes are required. In this paper, we propose the useful pure electric braking, which would involve ordinary brakes by only regenerative brakes without any mechanical brakes at high speed. Benefits of our proposal include a DC-electrification system with regenerative substations that can return powers to the commercial power system and a train that can use the full regenerative braking force. We furthermore evaluate the effects on running time and energies saved by regenerative substations in the proposed method.

  10. Electrical Characterization of 4H-SiC JFET Wafer: DC Parameter Variations for Extreme Temperature IC Design

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Chen, Liangyu; Spry, David J.; Beheim, Glenn M.; Chang, Carl W.

    2014-01-01

    This work reports DC electrical characterization of a 76 mm diameter 4H-SiC JFET test wafer fabricated as part of NASA's on-going efforts to realize medium-scale ICs with prolonged and stable circuit operation at temperatures as high as 500 degC. In particular, these measurements provide quantitative parameter ranges for use in JFET IC design and simulation. Larger than expected parameter variations were observed both as a function of position across the wafer as well as a function of ambient testing temperature from 23 degC to 500 degC.

  11. The design of an energy harvesting device for prolonging the working time of DC equipment

    NASA Astrophysics Data System (ADS)

    Wen, Yayuan; Deng, Huaxia; Zhang, Jin; Yu, Liandong

    2016-01-01

    Energy harvesting (EH) derives from the idea of converting the ambient energy into electric energy, which can solve the problem of DC supply for some electronic equipment. PZT is a typical piezoelectric material of inorganic, which has been developed as EH devices to transfer ambient vibration energy into electric energy. However, these PZT devices require relatively violent excitation, and easy to be fatigue fracture under the resonance condition. In this paper, PVDF, which is a kind of soft piezoelectric polymer, is adopted for developing transducer. The PVDF devices are flexible and have longer life time than PZT devices under the harmonic environment. The EH researches are mainly focused on the development of energy transfer efficiency either by the mechanical structure of transducer or the improvement of circuit. However, the practicality and stability of the EH devices are important in the practical engineering applications. In this paper, a charge amplifier is introduced in the circuit in order to guarantee the stability of the battery charging under small ambient vibration conditions. The model of the mechanical structure of PVDF and the electric performance of circuit are developed. The experimental results and simulation show that the stability of battery charging is improved and the working time of DC equipment is prolonged.

  12. A novel design of DC-AC electrical machine rotary converter for hybrid solar and wind energy applications

    NASA Astrophysics Data System (ADS)

    Mohammed, K. G.; Ramli, A. Q.; Amirulddin, U. A. U.

    2013-06-01

    This paper proposes the design of a new bi-directional DC-AC rotary converter machine to convert a d.c. voltage to three-phase voltage and vice-versa using a two-stage energy conversion machine. The rotary converter consists of two main stages which are combined into single frame. These two stages are constructed from three main electromagnetic components. The first inner electromagnetic component represents the input stage that enables the DC power generated by solar energy from photo-voltaic cells to be transformed by the second and third components electro-magnetically to produce multi-phase voltages at the output stage. At the same time, extra kinetic energy from wind, which is sufficiently available, can be added to existing torque on the second electromagnetic component. Both of these input energies will add up to the final energy generated at the output terminals. Therefore, the machine will be able to convert solar and wind energies to the output terminals simultaneously. If the solar energy is low, the available wind energy will be able to provide energy to the output terminals and at the same time charges the batteries which are connected as backup system. At this moment, the machine behaves as wind turbine. The energy output from the machine benefits from two energy sources which are solar and wind. At night when the solar energy is not available and also the load is low, the wind energy is able to charge the batteries and at the same time provides output electrical power to the remaining the load. Therefore, the proposed system will have high usage of available renewable energy as compared to separated wind or solar systems. MATLAB codes are used to calculate the required dimensions, the magnetic and electrical circuits parameters to design of the new bi-directional rotary converter machine.

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

    SciTech Connect

    2012-01-30

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

  14. Design and installation of DC plasma reactor for SiC nanoparticle production

    NASA Astrophysics Data System (ADS)

    Yu, I. K.; Rhee, J. H.; Cho, S.; Yoon, H. K.

    2009-04-01

    In order to get the high quality SiC nanopowders, a DC plasma reactor system with adjustable torch has been developed. SiC nanopowders were synthesized using this system and the synthesized primary particles have nearly spherical structures, mostly β-SiC phase with a particle size of 10-30 nm. Larger aggregate particles have been produced in our system probably due to longer particle growth times and faster collisions. The synthesized particles collected from the reactor wall and cyclone bottom have some free silicon and free carbon. To produce high quality silicon carbide nanopowders, it is highly necessary to improve the experimental conditions such as lower system pressures, shorter residence time, and higher quenching rates during powder synthesis.

  15. Design of DC-contact RF MEMS switch with temperature stability

    SciTech Connect

    Sun, Junfeng; Li, Zhiqun; Zhu, Jian; Yu, Yuanwei; Jiang, Lili

    2015-04-15

    In order to improve the temperature stability of DC-contact RF MEMS switch, a thermal buckle-beam structure is implemented. The stability of the switch pull-in voltage versus temperature is not only improved, but also the impact of stress and stress gradient on the drive voltage is suppressed. Test results show that the switch pull-in voltage is less sensitive to temperature between -20 °C and 100 °C. The variable rate of pull-in voltage to temperature is about -120 mV/°C. The RF performance of the switch is stable, and the isolation is almost independent of temperature. After being annealed at 280 °C for 12 hours, our switch samples, which are suitable for packaging, have less than 1.5% change in the rate of pull-in voltage.

  16. System and method for single-phase, single-stage grid-interactive inverter

    SciTech Connect

    Liu, Liming; Li, Hui

    2015-09-01

    The present invention provides for the integration of distributed renewable energy sources/storages utilizing a cascaded DC-AC inverter, thereby eliminating the need for a DC-DC converter. The ability to segment the energy sources and energy storages improves the maintenance capability and system reliability of the distributed generation system, as well as achieve wide range reactive power compensation. In the absence of a DC-DC converter, single stage energy conversion can be achieved to enhance energy conversion efficiency.

  17. Design and Development of High Voltage Direct Current (DC) Sources for the Solar Array Module Plasma Interaction Experiment

    NASA Technical Reports Server (NTRS)

    Bibyk, Irene K.; Wald, Lawrence W.

    1995-01-01

    Two programmable, high voltage DC power supplies were developed as part of the flight electronics for the Solar Array Module Plasma Interaction Experiment (SAMPIE). SAMPIE's primary objectives were to study and characterize the high voltage arcing and parasitic current losses of various solar cells and metal samples within the space plasma of low earth orbit (LEO). High voltage arcing can cause large discontinuous changes in spacecraft potential which lead to damage of the power system materials and significant Electromagnetic Interference (EMI). Parasitic currents cause a change in floating potential which lead to reduced power efficiency. These primary SAMPIE objectives were accomplished by applying artificial biases across test samples over a voltage range from -600 VDC to +300 VDC. This paper chronicles the design, final development, and test of the two programmable high voltage sources for SAMPIE. The technical challenges to the design for these power supplies included vacuum, space plasma effects, thermal protection, Shuttle vibrations and accelerations.

  18. Development of a rotary power transformer and inverter drive for spacecraft

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.; Bridgeforth, A. O.

    1983-01-01

    Many future satellites and spacecraft with spun and despun configurations will require the transfer of power across rotating interfaces in lieu of slip-rings and/or flexures. This is particularly true of spacecraft that have to demonstrate a long life expectancy. The rotary transformer has the desirable characteristics of high reliability and low noise, which qualify it as a potential replacement for slip rings. Development of a rotary power transformer follows the successful completion of a task to develop rotary signal-level transformers for the Galileo Spacecraft Project. The physical configuration of a rotary power transformer has a significant effect on its magnetic and electrical characteristics and therefore impacts the design of the dc/ac inverter driver. Important characteristics addressed during this development effort include: operating frequency, efficiency, transformer gap size, leakage inductance, and leakage flux. A breadboard inverter and rotary transformer were designed, fabricated and tested.

  19. Assumption or Fact? Line-to-Neutral Voltage Expression in an Unbalanced 3-Phase Circuit during Inverter Switching

    ERIC Educational Resources Information Center

    Masrur, M. A.

    2009-01-01

    This paper discusses the situation in a 3-phase motor or any other 3-phase system operating under unbalanced operating conditions caused by an open fault in an inverter switch. A dc voltage source is assumed as the input to the inverter, and under faulty conditions of the inverter switch, the actual voltage applied between the line to neutral…

  20. Design studies on a 500 kV DC gun photo-injector for the BXERL test facility

    NASA Astrophysics Data System (ADS)

    Liu, Sheng-Guang; Xu, Jin-Qiang

    2011-01-01

    BXERL is a proposal for a test facility (Beijing X-ray Energy Recovery Linac), which requires its injector to provide an electron beam of 5 MeV, 77 pC/bunch at a repetition rate of 130 MHz (average current of 10 mA). In this paper, we present the design of the injector, which consists of a 500 kV photocathode DC gun equipped with a GaAs cathode preparation device, a 1.3 GHz normal conducting RF buncher, two solenoids, and one cryomodule containing two 1.3 GHz 2-cell superconducting RF cavities as the energy booster. The detailed beam dynamics show that the injector can generate electron bunches with a RMS normalized emittance of 1.49 πmm·mrad, a bunch length of 0.67 mm, a beam energy of 5 MeV and an energy spread of 0.72%.

  1. Design and characterization of the DC acceleration and transport system required for the IMW Free Electron Master experiment

    SciTech Connect

    Caplan, M.; Van Der Geer, C.; Valentini, M.; Urbanus, W.

    1995-08-01

    A Free Electron Maser (FEM) has been constructed and is soon to be tested at the FOM Institute (Rijnhuizen) Netherlands with the ultimate goal of producing 1 MW long pulse to CW microwave output in the range 130 GHz to 250 GHz. The DC acceleration and beam transport systems is eventually to be used in a depressed collector configuration requiring 99.8% beam transmission in order that the High Voltage 2MV supply be required only to supply 20 milliamps of body current. A relativistic version of the Herrmann optical theory originally developed for microwave tube beams is used to take in account thermal electrons far out on the gaussian distribution tail which can translate into beam current well outside the ideal beam edge. This theory is applied to the FOM beamline design and predicts that the beam envelope containing 99.8% of the current can be successfully transported to the undulator for a wide range of assume d emittance values.

  2. 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.

  3. A high-power switch-mode dc power supply for dynamic loads

    SciTech Connect

    Shimer, D.W.; Lange, A.C.; Bombay, J.N.

    1994-06-23

    High-voltage dc power supplies are often required to operate with highly dynamic loads, such as arcs. A switch-mode dc power supply can offer significant advantages over conventional thyristor-based dc power supplies under such conditions. It can quickly turn off the supply to extinguish the arc, and it can quickly recover after the arc. It has a relatively small output filter capacitance, which results in small stored energy available to the arc. A 400-kW, 50-kV switch-mode dc power supply for an electron-beam gun that exploits these advantages was designed and tested. It uses four 100-kW, current-source-type dc-dc converters with inputs in parallel and outputs in series. The dc-dc converters operate at 20 kHz in the voltage regulator part and 10 kHz in the inverter, transformer, and output rectifier part of the circuit. Insulated gate bipolar transistors (IGBTs) are used as the power switches. Special techniques are used to protect the power supply and load against arcs and hard shorts. The power supply has an efficiency of 93%, an output voltage ripple of 1%, and fast dynamic response. In addition, it is nearly one-third the size of conventional power supplies.

  4. 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.

  5. 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.

  6. Variable frequency inverter for ac induction motors with torque, speed and braking control

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1975-01-01

    A variable frequency inverter was designed for driving an ac induction motor which varies the frequency and voltage to the motor windings in response to varying torque requirements for the motor so that the applied voltage amplitude and frequency are of optimal value for any motor load and speed requirement. The slip frequency of the motor is caused to vary proportionally to the torque and feedback is provided so that the most efficient operating voltage is applied to the motor. Winding current surge is limited and a controlled negative slip causes motor braking and return of load energy to a dc power source.

  7. Zr-ZrO2 cermet solar coatings designed by modelling calculations and deposited by dc magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Zhang, Qi-Chu; Hadavi, M. S.; Lee, K.-D.; Shen, Y. G.

    2003-03-01

    High solar performance Zr-ZrO2 cermet solar coatings were designed using a numerical computer model and deposited experimentally. The layer thickness and Zr metal volume fraction for the Zr-ZrO2 cermet solar selective coatings on a Zr or Al reflector with a surface ZrO2 or Al2O3 anti-reflection layer were optimized to achieve maximum photo-thermal conversion efficiency at 80°C under concentration factors of 1-20 using the downhill simplex method in multi-dimensions in the numerical calculation. The dielectric function and the complex refractive index of Zr-ZrO2 cermet materials were calculated using Sheng's approximation. Optimization calculations show that Al2O3/Zr-ZrO2/Al solar coatings with two cermet layers and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimized Al2O3/Zr-ZrO2/Al solar coating film with two cermet layers has a high solar absorptance value of 0.97 and low hemispherical emittance value of 0.05 at 80°C for a concentration factor of 2. The Al2O3/Zr-ZrO2/Al solar selective coatings with two cermet layers were deposited using dc magnetron sputtering technology. During the deposition of Zr-ZrO2 cermet layer, a Zr metallic target was run in a gas mixture of argon and oxygen. By control of oxygen flow rate the different metal volume fractions in the cermet layers were achieved using dc reactive sputtering. A solar absorptance of 0.96 and normal emittance of 0.05 at 80°C were achieved.

  8. DC CICC retrofit magnet preliminary design, software development and analysis report

    SciTech Connect

    Myatt, R.L.; Marston, P.G.

    1992-05-28

    The January 1992 quarterly progress report discusses a two-dimensional finite element analysis (FEA) of the proposed retrofit MHD coil. The superconducting Cable-in-Conduit Conductor (CICC) winding pack has a smooth, semi-elliptical cross section and is supported by a similarly shaped strap which resists the electromagnetic forces tending to separate the coils on each side of the channel. The coils are designed to produce a peak on-axis field of 4.5 tesla with a nominal current density of 13.05{times}10{sup 6} A/m{sup 2}. A sketch of the magnet system and structure is shown in Fig. 1.0-1. The objective of this analysis is to quantify the highly 3-D characteristics of the proposed superconductivity magnet system, and develop an appropriate support concept. A fully paramatized 3-D finite element model of the coil and structure is developed as a means of obtaining the field and stress solutions. The flexibility of FEA and a model built using design parameters allows variations in the coil end turn bend radius, strap thickness, support details and positions to be studied. The preliminary results show the calculated stresses as a result of this iterative design process.

  9. Medicare Auctions: A Case Study of Market Design in Washington, DC

    NASA Astrophysics Data System (ADS)

    Cramton, Peter

    One sensible way to reduce healthcare costs is to harness market forces, where practical, to nurture competition and innovation. Lower prices and improved services should follow. However, the switch to market pricing is not an easy one. Medicare's experience with medical supplies illustrates the challenges and offers some important lessons. The key lesson is that government programs can benefit from introducing market methods, but doing so requires good market design - something that may not come naturally to the implementing agency, especially in light of political forces and organizational inertia.

  10. Design and testing of a dc ion injector suitable for accelerator-driven transmutation

    SciTech Connect

    Schneider, J.D.; Meyer, E.; Stevens, R.R. Jr.; Hansborough, L.; Sherman, J.

    1994-08-01

    For a number of years, Los Alamos have collaborated with a team of experimentalists at Chalk River Labs who were pursuing the development of the front end of a high power cw proton accelerator. With the help of internal laboratory funding and modest defense conversion funds, we have set up and operated the accelerator at Los Alamos Operational equipment includes a slightly modified Chalk River Injector Test Stand (CRITS) including a 50 keV proton injector and a 1.25 MeV radio-frequency quadrupole (RFQ) with a klystrode rf power system. Many of the challenges involved in operating an rf linear accelerator to provide neutrons for an accelerator-driven reactor are encountered at the front (low energy) end of this system. The formation of the ion beam, the control of the beam parameters, and the focusing and matching of a highly space-charge-dominated beam are major problems. To address the operating problems in this critical front end, the Accelerator Operations and Technology Division at the Los Alamos National Laboratory has designed the APDF (Accelerator Prototype Demonstration Facility). The front end of this facility is a 75 keV, high-current, ion injector which has been assembled and is now being tested. This paper discusses the design modifications required in going from the 50 keV CRITS injector to the higher current, 75 keV injector. Major innovative changes were made in the design of this injector. This design eliminates all the control electronics and most of the ion source equipment at high potential. Also, a new, high-quality, ion-extractor system has been built. A dual-solenoid lens will be used in the low energy beam transport (LEBT) line to provide the capability of matching the extracted beam to a high-current ADTT linac. This new injector is the first piece of hardware in the APDF program and will be used to develop the long-term, reliable cw beam operation required for ADIT applications.

  11. Design of Super-Paramagnetic Core-Shell Nanoparticles for Enhanced Performance of Inverted Polymer Solar Cells.

    PubMed

    Jaramillo, Johny; Boudouris, Bryan W; Barrero, César A; Jaramillo, Franklin

    2015-11-18

    tangible pathway toward the development of enhanced design schemes for inorganic nanoparticles such that magnetic and energy control pathways can be tailored for flexible electronic applications. PMID:26506008

  12. 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.

  13. Design, conditioning, and performance of a high voltage, high brightness dc photoelectron gun with variable gap

    SciTech Connect

    Maxson, Jared; Bazarov, Ivan; Dunham, Bruce; Dobbins, John; Liu, Xianghong; Smolenski, Karl

    2014-09-15

    A new high voltage photoemission gun has been constructed at Cornell University which features a segmented insulator and a movable anode, allowing the cathode-anode gap to be adjusted. In this work, we describe the gun's overall mechanical and high voltage design, the surface preparation of components, as well as the clean construction methods. We present high voltage conditioning data using a 50 mm cathode-anode gap, in which the conditioning voltage exceeds 500 kV, as well as at smaller gaps. Finally, we present simulated emittance results obtained from a genetic optimization scheme using voltage values based on the conditioning data. These results indicate that for charges up to 100 pC, a 30 mm gap at 400 kV has equal or smaller 100% emittance than a 50 mm gap at 450 kV, and also a smaller core emittance, when placed as the source for the Cornell energy recovery linac photoinjector with bunch length constrained to be <3 ps rms. For 100 pC up to 0.5 nC charges, the 50 mm gap has larger core emittance than the 30 mm gap, but conversely smaller 100% emittance.

  14. Reliable inverter systems

    NASA Technical Reports Server (NTRS)

    Nagano, S.

    1979-01-01

    Base driver with common-load-current feedback protects paralleled inverter systems from open or short circuits. Circuit eliminates total system oscillation that can occur in conventional inverters because of open circuit in primary transformer winding. Common feedback signal produced by functioning modules forces operating frequency of failed module to coincide with clock drive so module resumes normal operating frequency in spite of open circuit.

  15. 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

  16. Design of a hairpin polyamide, ZT65B, for targeting the inverted CCAAT box (ICB) site in the multidrug resistant (MDR1) gene.

    PubMed

    Buchmueller, Karen L; Taherbhai, Zarmeen; Howard, Cameron M; Bailey, Suzanna L; Nguyen, Binh; O'Hare, Caroline; Hochhauser, Daniel; Hartley, John A; Wilson, W David; Lee, Moses

    2005-12-01

    A novel hairpin polyamide, ZT65B, containing a 3-methylpicolinate moiety was designed to target the inverted CCAAT box (ICB) of the human multidrug resistance 1 gene (MDR1) promoter. Binding of nuclear factor-Y (NF-Y) to the ICB site upregulates MDR1 gene expression and is, therefore, a good target for anticancer therapeutic agents. However, it is important to distinguish amongst different promoter ICB sites so that only specific genes will be affected. All ICB sites have the same sequence but they differ in the sequence of the flanking base pairs, which can be exploited in the design of sequence-specific polyamides. To test this hypothesis, ten ICB-containing DNA hairpins were designed with different flanking base pairs; the sequences ICBa and ICBb were similar to the 3'-ICB site of MDR1 (TGGCT). Thermal-denaturation studies showed that ZT65B effectively targeted ICBa and ICBb (DeltaTM=6.5 and 7.0 degrees C) in preference to the other DNA hairpins (<3.5 degrees C), with the exception of ICBc (5.0 degrees C). DNase I-footprinting assays were carried out with the topoisomerase IIalpha-promoter sequence, which contains five ICB sites; of these, ICB1 and ICB5 are similar to the ICB site of MDR1. ZT65B was found to selectively bind ICB1 and ICB5; footprints were not observed with ICB2, ICB3, or ICB4. A strong, positive induced ligand band at 325 nm in CD studies confirmed that ZT65B binds in the DNA minor groove. The selectivity of ZT65B binding to hairpins that contained the MDR1 ICB site compared to one that did not (ICBd) was confirmed by surface-plasmon studies, and equilibrium constants of 5x10(6)-1x10(7) and 4.6x10(5) M-1 were obtained with ICB1, ICB5,and ICB2 respectively. ZT65B and the previously published JH37 (J. A. Henry, et al. Biochemistry 2004, 43, 12 249-12 257) serve as prototypes for the design of novel polyamides. These can be used to specifically target the subset of ubiquitous gene elements known as ICBs, and thereby affect the expression of one or

  17. Design of Linear DC Motor Two-degree-of-freedom Positioning System using Model Reference type Sliding Mode Controller

    NASA Astrophysics Data System (ADS)

    Urushihara, Shiro; Kamano, Takuya; Yura, Satoshi; Yasuno, Takashi; Suzuki, Takayuki

    One of fundamental problems in the factory automation is how to obtain linear motion. Linear motors produce directly the linear motion force without a motion-transform mechanism. Linear d.c. motors (LDMs) have excellent performance and controllability. However, the dynamics of small-sized LDMs is adversely affected by the dead-band due to the friction between brushes and commutators. In this paper, it is described that the design of the two-degree-of-freedom positioning system with a LDM using model reference type sliding mode controller (SMC). The proposed positioning system consists of a fixed gain feedforward controller and a SMC used as a feedback controller. The objective of the SMC is to repress the influence of nonlinear characteristics (the dead-band and parameter variations etc.). The tracking performance can be improved as the fixed gain feedforward controller makes a dynamic inverse system in the feedforward path. The effectiveness of the proposed system for improvement of the tracking performance is demonstrated by experimental results.

  18. 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.

  19. DC-to-DC switching converter

    NASA Technical Reports Server (NTRS)

    Cuk, Slobodan M. (Inventor); Middlebrook, Robert D. (Inventor)

    1980-01-01

    A dc-to-dc converter having nonpulsating input and output current uses two inductances, one in series with the input source, the other in series with the output load. An electrical energy transferring device with storage, namely storage capacitance, is used with suitable switching means between the inductances to DC level conversion. For isolation between the source and load, the capacitance may be divided into two capacitors coupled by a transformer, and for reducing ripple, the inductances may be coupled. With proper design of the coupling between the inductances, the current ripple can be reduced to zero at either the input or the output, or the reduction achievable in that way may be divided between the input and output.

  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. Design of power electronics for TVC and EMA systems

    NASA Astrophysics Data System (ADS)

    Nelms, R. Mark; Bell, J. Brett; Shepherd, Michael T.

    1994-11-01

    The Component Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. A previous project performed by Auburn University examined the use of the resonant dc link (RDCL) inverter, pulse density modulation (PDM), and mos-controlled thyristors (MCT's) for speed control of a brushless dc motor. The speed of the brushless dc motor is proportional to the applied stator voltage. In a PDM system, the control system determines the number of resonant voltage pulses which must be applied to the stator to achieve a desired speed. The addition of a waveshaping circuit to the front end of a standard three-phase inverter yields a RDCL inverter; the resonant voltage pulses are produced through the action of this wave shaping circuit and the inverter. This project has focused on the implementation of a system which permits zero-voltage switching with the bus voltage clamped at the input voltage level. In the same manner as the RDCL inverter, the inverter selected for this implementation is a combination of waveshaping circuit and a standard three-phase inverter. In addition, this inverter allows a pulse-width modulated (PWM)-like control scheme instead of a PDM scheme. The operation of waveshaping circuit will be described through analysis and waveforms. Design relationships will also be presented.

  2. Design of power electronics for TVC and EMA systems

    NASA Technical Reports Server (NTRS)

    Nelms, R. Mark; Bell, J. Brett; Shepherd, Michael T.

    1994-01-01

    The Component Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. A previous project performed by Auburn University examined the use of the resonant dc link (RDCL) inverter, pulse density modulation (PDM), and mos-controlled thyristors (MCT's) for speed control of a brushless dc motor. The speed of the brushless dc motor is proportional to the applied stator voltage. In a PDM system, the control system determines the number of resonant voltage pulses which must be applied to the stator to achieve a desired speed. The addition of a waveshaping circuit to the front end of a standard three-phase inverter yields a RDCL inverter; the resonant voltage pulses are produced through the action of this wave shaping circuit and the inverter. This project has focused on the implementation of a system which permits zero-voltage switching with the bus voltage clamped at the input voltage level. In the same manner as the RDCL inverter, the inverter selected for this implementation is a combination of waveshaping circuit and a standard three-phase inverter. In addition, this inverter allows a pulse-width modulated (PWM)-like control scheme instead of a PDM scheme. The operation of waveshaping circuit will be described through analysis and waveforms. Design relationships will also be presented.

  3. Dynamic performance and control of a static var generator using cascade multilevel inverters

    SciTech Connect

    Peng, Fang Zheng; Lai, Jih-Sheng

    1996-10-01

    A cascade multilevel inverter is proposed for static VAR shifting, compensation/generation applications. The new cascade M-level inverter consists of (M-1)/2 single-phase full bridges in which each bridge has its own separate dc source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle. It can eliminate the need for transformers in multipulse inverters. A prototype static VAR generator (SVG) system using 11- level cascade inverter (21-level line-to-line voltage waveform) has been built. The output voltage waveform is equivalent to that of a 60- pulse inverter. This paper focuses on dynamic performance of the cascade inverter based SVG system. Control schemes are proposed to achieve a fast response which is impossible for a conventional static VAR compensator (SVC). Analytical, simulated and experimental results show the superiority of the proposed SVG system.

  4. Integrated-Circuit Controller For Brushless dc Motor

    NASA Technical Reports Server (NTRS)

    Le, Dong Tuan

    1994-01-01

    Generic circuit performs commutation-logic and power-switching functions for control of brushless dc motor. Controller includes commutation-logic and associated control circuitry, power supply, and inverters containing power transistors. Major advantages of controller are size, weight, and power consumption can be made less than other brushless-dc-motor controllers.

  5. Simplified dc to dc converter

    NASA Technical Reports Server (NTRS)

    Gruber, R. P. (Inventor)

    1984-01-01

    A dc to dc converter which can start with a shorted output and which regulates output voltage and current is described. Voltage controlled switches directed current through the primary of a transformer the secondary of which includes virtual reactance. The switching frequency of the switches is appropriately varied to increase the voltage drop across the virtual reactance in the secondary winding to which there is connected a low impedance load. A starting circuit suitable for voltage switching devices is provided.

  6. 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).

  7. Development and performance of pulse-width-modulated static inverter and converter modules

    NASA Technical Reports Server (NTRS)

    Pittman, P. F.; Gourash, F.; Birchenough, A. G.; Pittman, P. F.; Ravas, R. J.; Hall, W. G.

    1971-01-01

    Pulse-width-modulated inverter and converter modules are being developed for modular aerospace electrical power systems. The modules, rate 2.5 kilowatts per module and 10-minute - 150-percent overload, operate from 56 volts dc. The converter module provides two output voltages: a nominal link voltage of 200 volts dc when used with the inverter, and 150 volts dc to a load bus when used separately. The inverter module output is 400-hertz, sinusoidal, three-phase, 120/208 volts. Tests of breadboard models with standard parts and integrated circuits show rated power efficiencies of 71.4 and 85.1 percent and voltage regulation of 5 and 3.1 percent for inverter and converter modules, respectively. Sine-wave output distortion is 0.74 percent.

  8. Inverting the Achievement Pyramid

    ERIC Educational Resources Information Center

    White-Hood, Marian; Shindel, Melissa

    2006-01-01

    Attempting to invert the pyramid to improve student achievement and increase all students' chances for success is not a new endeavor. For decades, educators have strategized, formed think tanks, and developed school improvement teams to find better ways to improve the achievement of all students. Currently, the No Child Left Behind Act (NCLB) is…

  9. A current-source inverter fed induction motor drive system with reduced losses

    SciTech Connect

    Espinoza, J.R.; Joos, G.

    1995-12-31

    Standard low and medium induction power motor drives are based on the PWM voltage source inverter (VSI) fed from a diode rectifier. The dual topology, based on the current source inverter/rectifier structure is used in medium and high power applications. This paper addresses some of the drawbacks of this approach compared to the voltage source approach. The proposed drive features: (a) an on-line operated PWM inverter, using instantaneous output capacitor voltage control based on space vector modulation; (b) a line-synchronized PWM rectifier, with dc bus current control; (c) an additional inverter modulation index control loop, ensuring a constant inverter modulation index. The resulting advantages include: (a) ruggedness and inherent continuous regeneration capability; (b) near unity global input power factor; (c) reduced motor voltage distortion; (d) reduced dc bus inductor and switch conduction losses; (e) fast motor dynamic response; (f) elimination of motor circuit resonances. Simulated and experimental results based on a DSP implementation are given.

  10. 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

  11. Program Predicts Nonlinear Inverter Performance

    NASA Technical Reports Server (NTRS)

    Al-Ayoubi, R. R.; Oepomo, T. S.

    1985-01-01

    Program developed for ac power distribution system on Shuttle orbiter predicts total load on inverters and node voltages at each of line replaceable units (LRU's). Mathematical model simulates inverter performance at each change of state in power distribution system.

  12. DC to DC battery charger

    SciTech Connect

    Carr, F.L.; Terrill, L.R.

    1987-01-20

    A DC to DC battery charger is described for a vehicle comprising: adapter plug means for making electrical connections to a first battery through a cigarette lighter socket in the vehicle; means of making electrical connections to a second battery to be charged; a DC to AC converter and an AC to DC rectifier for elevating the voltage from the first battery to a voltage above that of the second battery; integrated circuit means for generating a pulse width modulated current as a function for the charged condition of the second battery; transistor switch means supplied with the pulse width modulated current for developing a charging voltage; a choke coil and a capacitor serially connected to the transistor switch means; and a diode connected across the choke coil and the capacitor whereby the capacitor is charged during pulses of current from the transistor switch means through the choke coil. The choke coil reverses polarity at the termination of the pulses of current and continues to charge the battery through the diode. The DC rectified voltage is controlled by the integrated circuit means for regulating current through the choke coil.

  13. FET commutated current-FED inverter

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor); Edwards, Dean B. (Inventor)

    1983-01-01

    A shunt switch comprised of a field-effect transistor (Q.sub.1) is employed to commutate a current-fed inverter (10) using thyristors (SCR1, SCR2) or bijunction transistors (Q.sub.2, Q.sub.3) in a full bridge (1, 2, 3, 4) or half bridge (5, 6) and transformer (T.sub.1) configuration. In the case of thyristors, a tapped inverter (12) is employed to couple the inverter to a dc source to back bias the thyristors during commutation. Alternatively, a commutation power supply (20) may be employed for that purpse. Diodes (D.sub.1, D.sub.2) in series with some voltage dropping element (resistor R.sub.12 or resistors R.sub.1, R.sub.2 or Zener diodes D.sub.4, D.sub.5) are connected in parallel with the thyristors in the half bridge and transformer configuration to assure sharing the back bias voltage. A clamp circuit comprised of a winding (18) negatively coupled to the inductor and a diode (D.sub.3) return stored energy from the inductor to the power supply for efficient operation with buck or boost mode.

  14. Analysis of self-oscillating dc-to-dc converters

    NASA Technical Reports Server (NTRS)

    Burger, P.

    1974-01-01

    The basic operational characteristics of dc-to-dc converters are analyzed along with the basic physical characteristics of power converters. A simple class of dc-to-dc power converters are chosen which could satisfy any set of operating requirements, and 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 whose curves are related to other operational characteristics, such as ripple and regulation. Further research is suggested for the solution of absolute stability and efficient physical design of this class of power converters.

  15. Two-Stage Series-Resonant Inverter

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.

    1994-01-01

    Two-stage inverter includes variable-frequency, voltage-regulating first stage and fixed-frequency second stage. Lightweight circuit provides regulated power and is invulnerable to output short circuits. Does not require large capacitor across ac bus, like parallel resonant designs. Particularly suitable for use in ac-power-distribution system of aircraft.

  16. Inverter Matrix for the Clementine Mission

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Blaes, B. R.; Tardio, G.; Soli, G. A.

    1994-01-01

    An inverter matrix test circuit was designed for the Clementine space mission and is built into the RRELAX (Radiation and Reliability Assurance Experiment). The objective is to develop a circuit that will allow the evaluation of the CMOS FETs using a lean data set in the noisy spacecraft environment.

  17. Inverted organic photovoltaic cells.

    PubMed

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated. PMID:27087582

  18. Inverted organic photosensitive device

    SciTech Connect

    Forrest, Stephen R.; Tong, Xiaoran; Lee, Jun Yeob; Cho, Yong Joo

    2015-09-08

    There is disclosed a method for preparing the surface of a metal substrate. The present disclosure also relates to an organic photovoltaic device including a metal substrate made by such method. Also disclosed herein is an inverted photosensitive device including a stainless steel foil reflective electrode, an organic donor-acceptor heterojunction over the reflective electrode, and a transparent electrode over the donor-acceptor heterojunction.

  19. Fundamental Frequency Switching Control of Seven-Level Hybrid Cascaded H-bridge Multilevel Inverter

    SciTech Connect

    Du, Zhong; Chiasson, John N; Ozpineci, Burak; Tolbert, Leon M

    2009-01-01

    This paper presents a cascaded H-bridge multilevel inverter that can be implemented using only a single dc power source and capacitors. Standard cascaded multilevel inverters require n dc sources for 2n + 1 levels. Without requiring transformers, the scheme proposed here allows the use of a single dc power source (e.g., a battery or a fuel cell stack) with the remaining n-1 dc sources being capacitors, which is referred to as hybrid cascaded H-bridge multilevel inverter (HCMLI) in this paper. It is shown that the inverter can simultaneously maintain the dc voltage level of the capacitors and choose a fundamental frequency switching pattern to produce a nearly sinusoidal output. HCMLI using only a single dc source for each phase is promising for high-power motor drive applications as it significantly decreases the number of required dc power supplies, provides high-quality output power due to its high number of output levels, and results in high conversion efficiency and low thermal stress as it uses a fundamental frequency switching scheme. This paper mainly discusses control of seven-level HCMLI with fundamental frequency switching control and how its modulation index range can be extended using triplen harmonic compensation.

  20. Transistorized PWM inverter-induction motor drive system

    NASA Technical Reports Server (NTRS)

    Peak, S. C.; Plunkett, A. B.

    1982-01-01

    This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

  1. Inverter Modeling For Accurate Energy Predictions Of Tracking HCPV Installations

    NASA Astrophysics Data System (ADS)

    Bowman, J.; Jensen, S.; McDonald, Mark

    2010-10-01

    High efficiency high concentration photovoltaic (HCPV) solar plants of megawatt scale are now operational, and opportunities for expanded adoption are plentiful. However, effective bidding for sites requires reliable prediction of energy production. HCPV module nameplate power is rated for specific test conditions; however, instantaneous HCPV power varies due to site specific irradiance and operating temperature, and is degraded by soiling, protective stowing, shading, and electrical connectivity. These factors interact with the selection of equipment typically supplied by third parties, e.g., wire gauge and inverters. We describe a time sequence model accurately accounting for these effects that predicts annual energy production, with specific reference to the impact of the inverter on energy output and interactions between system-level design decisions and the inverter. We will also show two examples, based on an actual field design, of inverter efficiency calculations and the interaction between string arrangements and inverter selection.

  2. EMPLACEMENT DRIFT INVERT-LOW STEEL EVALUATION

    SciTech Connect

    M. E. Taylor and D. H. Tang

    2000-09-29

    and pallet beam width. Testing is also required to determine the bearing capacity of the tuff materials. Analysis of the all-ballast invert shows that the waste package/pallet assembly, as currently designed, can be supported by the compacted crushed tuff. The drip shield and related backfill loads cannot be supported by the compacted crushed tuff because of the narrow base angle that currently supports the drip shield. Increasing the width of the base angle of the drip shield will better distribute the drip shield and backfill load to the compacted crushed tuff. Testing is required to determine the bearing capacity of the tuff materials. Emplacement/retrieval equipment will also require analysis and development to be compatible with the all-ballast invert.

  3. Development of a dc 1 MV power supply technology for NB injectors

    NASA Astrophysics Data System (ADS)

    Watanabe, K.; Kashiwagi, M.; Kawashima, S.; Ono, Y.; Yamashita, Y.; Yamazaki, C.; Hanada, M.; Inoue, T.; Taniguchi, M.; Okumura, Y.; Sakamoto, K.

    2006-06-01

    Major issues of neutral beam (NB) injector power supplies are high-speed switching, regulation and transmission of dc ultra-high voltage (UHV) and suppression of surge energy input to the beam source at high voltage breakdown. A gate turn-off thyristor inverter type power supply where the control is performed on the low voltage ac side was designed for the ITER NB. Based on the remarkable progress of a high power IEGT (injection enhanced gate transistor), the design of the inverter has been modified to increase efficiency and compactness using such new elements. The power loss in the inverter is reduced to 0.5 MW from 1.6 MW by adopting the IEGT inverter system at the same frequency of 150 Hz. Further, power supply performance has been studied for higher frequency operation of the inverter at 300 Hz. It was confirmed that the voltage regulation was stable even when the filter capacitor was reduced to 1/5 of the original value by circuit simulation. For the transmission line of the dc UHV with intermediate voltages, a disc shape multi-conductor bushing with a transmission line test chamber has been developed. The dimensions of the bushing are 1.8 m (diameter) and 140 mm (thickness) at the edge. Electric fields at the conductor surface and insulator surface were designed to be lower than 5 kV mm-1 and 7 kV mm-1, respectively. An electric field at the bottom of the ground potential outer conductor was designed to be lower than 1.2 kV mm-1 to prevent particle levitation which triggers breakdown. The prototype transmission line has passed the lightning impulse test up to 1300 kV. A dc UHV up to 1175 kV was successfully sustained for 300 s. To prevent electric damage of the beam source at high voltage breakdown, core snubbers using Fe-based nanocrystalline soft magnetic materials have been adopted to dissipate the surge energy.

  4. Topology, Design, Analysis, and Thermal Management of Power Electronics for Hybrid Electric Vehicle Applications

    SciTech Connect

    Mi, C.; Peng, F. Z.; Kelly, K. J.; O'Keefe, M.; Hassani, V.

    2008-01-01

    Power electronics circuits play an important role in the success of electric, hybrid and fuel cell vehicles. Typical power electronics circuits in hybrid vehicles include electric motor drive circuits and DC/DC converter circuits. Conventional circuit topologies, such as buck converters, voltage source inverters and bidirectional boost converters are challenged by system cost, efficiency, controllability, thermal management, voltage and current capability, and packaging issues. Novel topologies, such as isolated bidirectional DC/DC converters, multilevel converters, and Z-source inverters, offer potential improvement to hybrid vehicle system performance, extended controllability and power capabilities. This paper gives an overview of the topologies, design, and thermal management, and control of power electronics circuits in hybrid vehicle applications.

  5. Molecular solid-state inverter-converter system

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.

    1973-01-01

    A modular approach for aerospace electrical systems has been developed, using lightweight high efficiency pulse width modulation techniques. With the modular approach, a required system is obtained by paralleling modules. The modular system includes the inverters and converters, a paralleling system, and an automatic control and fault-sensing protection system with a visual annunciator. The output is 150 V dc, or a low distortion three phase sine wave at 120 V, 400 Hz. Input power is unregulated 56 V dc. Each module is rated 2.5 kW or 3.6 kVA at 0.7 power factor.

  6. Inverted glass harp.

    PubMed

    Quinn, Daniel B; Rosenberg, Brian J

    2015-08-01

    We present an analytical treatment of the acoustics of liquid-filled wine glasses, or "glass harps." The solution is generalized such that under certain assumptions it reduces to previous glass harp models, but also leads to a proposed musical instrument, the "inverted glass harp," in which an empty glass is submerged in a liquid-filled basin. The versatility of the solution demonstrates that all glass harps are governed by a family of solutions to Laplace's equation around a vibrating disk. Tonal analyses of recordings for a sample glass are offered as confirmation of the scaling predictions. PMID:26382336

  7. Inverted glass harp

    NASA Astrophysics Data System (ADS)

    Quinn, Daniel B.; Rosenberg, Brian J.

    2015-08-01

    We present an analytical treatment of the acoustics of liquid-filled wine glasses, or "glass harps." The solution is generalized such that under certain assumptions it reduces to previous glass harp models, but also leads to a proposed musical instrument, the "inverted glass harp," in which an empty glass is submerged in a liquid-filled basin. The versatility of the solution demonstrates that all glass harps are governed by a family of solutions to Laplace's equation around a vibrating disk. Tonal analyses of recordings for a sample glass are offered as confirmation of the scaling predictions.

  8. DC coupled Doppler radar physiological monitor.

    PubMed

    Zhao, Xi; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

    2011-01-01

    One of the challenges in Doppler radar systems for physiological monitoring is a large DC offset in baseband outputs. Typically, AC coupling is used to eliminate this DC offset. Since the physiological signals of interest include frequency content near DC, it is not desirable to simply use AC coupling on the radar outputs. While AC coupling effectively removes DC offset, it also introduces a large time delay and distortion. This paper presents the first DC coupled IQ demodulator printed circuit board (PCB) design and measurements. The DC coupling is achieved by using a mixer with high LO to RF port isolation, resulting in a very low radar DC offset on the order of mV. The DC coupled signals from the PCB radar system were successfully detected with significant LNA gain without saturation. Compared to the AC coupled results, the DC coupled results show great advantages of less signal distortion and more accurate rate estimation. PMID:22254704

  9. Design and implementation of a new modified sliding mode controller for grid-connected inverter to controlling the voltage and frequency.

    PubMed

    Ghanbarian, Mohammad Mehdi; Nayeripour, Majid; Rajaei, Amirhossein; Mansouri, Mohammad Mahdi

    2016-03-01

    As the output power of a microgrid with renewable energy sources should be regulated based on the grid conditions, using robust controllers to share and balance the power in order to regulate the voltage and frequency of microgrid is critical. Therefore a proper control system is necessary for updating the reference signals and determining the proportion of each inverter in the microgrid control. This paper proposes a new adaptive method which is robust while the conditions are changing. This controller is based on a modified sliding mode controller which provides adapting conditions in linear and nonlinear loads. The performance of the proposed method is validated by representing the simulation results and experimental lab results. PMID:26704720

  10. Evaluation of a high power inverter for potential space applications

    NASA Technical Reports Server (NTRS)

    Guynes, B. V.; Lanier, J. R., Jr.

    1976-01-01

    The ADM-006 inverter discussed utilizes a unique method of using power switching circuits to produce three-phase low harmonic content voltages without any significant filtering. This method is referred to as the power center approach to inverter design and is explained briefly. The results are presented of tests performed by MSFC to evaluate inverter performance, especially when required to provide power to nonlinear loads such as half or full wave rectified loads with capacitive filtering. Test preocedures and results are described. These tests show that the power center inverter essentially met or exceeded all of claims excluding voltage regulation (3.9 percent versus specified 3.3 percent) and would be a good candidate for high power inverter applications such as may be found on Space Station, Spacelab, etc.

  11. Gas cooled traction drive inverter

    SciTech Connect

    Chinthavali, Madhu Sudhan

    2013-10-08

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  12. Gas cooled traction drive inverter

    DOEpatents

    Chinthavali, Madhu Sudhan

    2016-04-19

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  13. Alternative algebras admitting derivations with invertible values and invertible derivations

    NASA Astrophysics Data System (ADS)

    Kaygorodov, I. B.; Popov, Yu S.

    2014-10-01

    We prove an analogue of the Bergen-Herstein-Lanski theorem for alternative algebras: describe all alternative algebras that admit derivations with invertible values. We also prove an analogue of Moens' theorem for alternative algebras (a finite-dimensional alternative algebra over a field of characteristic zero is nilpotent if and only if it admits an invertible Leibniz derivation).

  14. Analysis and performance of paralleling circuits for modular inverter-converter systems

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.; Gourash, F.

    1972-01-01

    As part of a modular inverter-converter development program, control techniques were developed to provide load sharing among paralleled inverters or converters. An analysis of the requirements of paralleling circuits and a discussion of the circuits developed and their performance are included in this report. The current sharing was within 5.6 percent of rated-load current for the ac modules and 7.4 percent for the dc modules for an initial output voltage unbalance of 5 volts.

  15. 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.

  16. Magnetic materials selection for static inverter and converter transformers

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1973-01-01

    A program to study magnetic materials is described for use in spacecraft transformers used in static inverters, converters, and transformer-rectifier supplies. Different magnetic alloys best suited for high-frequency and high-efficiency applications were comparatively investigated together with an investigation of each alloy's inherent characteristics. The materials evaluated were the magnetic alloys: (1) 50% Ni, 50% Fe; (2) 79% Ni, 17% Fe, 4% Mo; (3) 48% Ni, 52% Fe; (4) 78% Ni, 17% Fe, 5% Mo; and (5) 3% Si, 97% Fe. Investigations led to the design of a transformer with a very low residual flux. Tests were performed to determine the dc and ac magnetic properties at 2400 Hz using square-wave excitation. These tests were performed on uncut cores, which were then cut for comparison of the gapped and ungapped magnetic properties. When the data of many transformers in many configurations were compiled the optimum transformer was found to be that with the lowest residual flux and a small amount of air gap in the magnetic material. The data obtained from these tests are described, and the potential uses for the materials are discussed.

  17. Simplified High-Power Inverter

    NASA Technical Reports Server (NTRS)

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  18. Breaking Barriers to Low-Cost Modular Inverter Production & Use

    SciTech Connect

    Bogdan Borowy; Leo Casey; Jerry Foshage; Steve Nichols; Jim Perkinson

    2005-05-31

    The goal of this cost share contract is to advance key technologies to reduce size, weight and cost while enhancing performance and reliability of Modular Inverter Product for Distributed Energy Resources (DER). Efforts address technology development to meet technical needs of DER market protection, isolation, reliability, and quality. Program activities build on SatCon Technology Corporation inverter experience (e.g., AIPM, Starsine, PowerGate) for Photovoltaic, Fuel Cell, Energy Storage applications. Efforts focused four technical areas, Capacitors, Cooling, Voltage Sensing and Control of Parallel Inverters. Capacitor efforts developed a hybrid capacitor approach for conditioning SatCon's AIPM unit supply voltages by incorporating several types and sizes to store energy and filter at high, medium and low frequencies while minimizing parasitics (ESR and ESL). Cooling efforts converted the liquid cooled AIPM module to an air-cooled unit using augmented fin, impingement flow cooling. Voltage sensing efforts successfully modified the existing AIPM sensor board to allow several, application dependent configurations and enabling voltage sensor galvanic isolation. Parallel inverter control efforts realized a reliable technique to control individual inverters, connected in a parallel configuration, without a communication link. Individual inverter currents, AC and DC, were balanced in the paralleled modules by introducing a delay to the individual PWM gate pulses. The load current sharing is robust and independent of load types (i.e., linear and nonlinear, resistive and/or inductive). It is a simple yet powerful method for paralleling both individual devices dramatically improves reliability and fault tolerance of parallel inverter power systems. A patent application has been made based on this control technology.

  19. 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.

  20. Piezometer completion report for borehold cluster sites DC-19, DC-20 and DC-22

    SciTech Connect

    Jackson, R.L.; Diediker, L.D.; Ledgerwood, R.K.; Veatch, M.D.

    1984-07-01

    This report describes the design and installation of multi-level piezometers at borehole cluster sites DC-19, DC-20 and DC-22. The network of borehole cluster sites will provide facilities for multi-level water-level monitoring across the RRL for piezometer baseline monitoring and for large-scale hydraulic stress testing. These groundwater-monitoring facilities were installed between August 1983 and March 1984. Three series of piezometer nests (A-, C- and D-series) were installed in nine hydrogeologic units (monitoring horizons) within the Columbia River Basalt Group at each borehole cluster site. In addition to the piezometer facilities, a B-series pumping well was installed at borehole cluster sites DC-20 and DC-22. The A-series piezometer nest monitors the basal Ringold sediments and the Rattlesnake Ridge interbed. The C-series piezometer nests monitors the six deepest horizons, which are in increasing depth, the Priest Rapids interflow. 21 refs., 6 figs., 14 tabs.

  1. Analysis and modeling of a family of two-transistor parallel inverters

    NASA Technical Reports Server (NTRS)

    Lee, F. C. Y.; Wilson, T. G.

    1973-01-01

    A family of five static dc-to-square-wave inverters, each employing a square-loop magnetic core in conjunction with two switching transistors, is analyzed using piecewise-linear models for the nonlinear characteristics of the transistors, diodes, and saturable-core devices. Four of the inverters are analyzed in detail for the first time. These analyses show that, by proper choice of a frame of reference, each of the five quite differently appearing inverter circuits can be described by a common equivalent circuit. This equivalent circuit consists of a five-segment nonlinear resistor, a nonlinear saturable reactor, and a linear capacitor. Thus, by proper interpretation and identification of the parameters in the different circuits, the results of a detailed solution for one of the inverter circuits provide similar information and insight into the local and global behavior of each inverter in the family.

  2. Design of power electronics for TVC and EMA systems

    NASA Technical Reports Server (NTRS)

    Nelms, R. Mark; Bell, J. Brett; Shepherd, Michael T.

    1994-01-01

    The EMA systems proposed for future space transportation applications are high power systems operating at voltages up to 270 Vdc and at current levels on the order of hundreds of amperes. The position of the actuator is controlled by modulating the flow of energy from the source to an electric motor with an inverter. Hard-switching of the semiconductor devices in the inverter results in considerable device switching stresses and losses and in the generation of substantial amounts of EMI. Both of these can be reduced by employing zero-voltage-switching (ZVS) techniques in the inverter. This project has focused on the development of a ZVS inverter for the Marshall Space Center EMA prototypes, which utilize brushless dc motors to convert electrical energy to mechanical energy. An inverter which permitted zero-voltage switching and a quasi-PWM operation was selected for study and implementation. A waveshaping circuit is added to the front of a standard three-phase inverter to achieve the desired switching properties. This circuit causes the input voltage of the three-phase inverter to ring to zero where it is clamped for a short period of time. During this zero-voltage period, any of the semiconductor switches in the three-phase inverter are switched on or off at zero voltage resulting in a reduction in switching losses and EMI. The operation of this waveshaping circuit and its interaction with the three-phase inverter are described. The different circuit modes were analyzed using equivalent circuits. Based on this analysis, design relationships were developed for calculating component values for the circuit elements in the waveshaping circuit. Waveforms of various voltages and currents in the waveshaping circuit were plotted and used to determine the ratings of the semiconductors in the waveshaping circuit. The implementation of this inverter are described. Block diagrams for the overall control system and the waveshaping circuit control are presented and discussed

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

    SciTech Connect

    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.

  4. Improved current control makes inverters the power sources of choice

    SciTech Connect

    Yamamoto, H.; Harada, S.; Ueyama, T.

    1997-02-01

    It is now generally understood that by increasing the operating or switching frequency of a power source the size of the main transformer and main reactor can be shrunk. Thus, a 300-A DC welding power source weighing well under 100 lb can be produced. This makes the inverter power source an ideal choice for applications requiring equipment maneuverability. It is also generally understood that due to higher switching frequencies, a smoother output is obtained from inverter power sources. In the late 1980s, the company developed a new double-inverter power source by which inverted DC weld output is inverted back to AC weld output. This product was the first of its kind in the world. Again, the small compact size of this product was of great interest. Utilizing current waveform control, it was realized that fast response switching from electrode negative to electrode positive could be accurately controlled, offering benefits such as AC GTA welding with high-frequency start only, even at a low welding current. The primary benefit is the ability to limit the electrode positive half cycle to less than 5%. The electrode positive half cycle is responsible for tungsten erosion, which also creates the balling effect of a tungsten electrode. By limiting the electrode positive portion of the AC cycle to a very low level, a rather sharp point can be maintained on the tungsten, which creates a very concentrated, focused arc column. This ability provides excellent joint penetration in fillet welding of aluminum alloys, especially on thick plate. It also reduces the heat-affected zone in AC GTA welding of aluminum.

  5. Development of Voltage Regulation Plan by Composing Subsystem with the SFES for DC On-line Electric Vehicle

    NASA Astrophysics Data System (ADS)

    Jung, S.; Lee, J. H.; Yoon, M.; Lee, H.; Jang, G.

    The study of the application process of the relatively small size 'Superconducting Flywheel Energy Storage (SFES)' system is conducted to regulate voltage fluctuation of the DC On-Line Electric Vehicle (OLEV) system, which is designed by using DC power system network. It is recommended to construct the power conversion system nearby the substation because the charging system is under the low voltage. But as the system is usually built around urban area and it makes hard to construct the subsystems at every station, voltage drop can occur in power supply inverter that is some distance from the substation. As the alternative of this issue, DC distribution system is recently introduced and has possibility to solve the above issue. In this paper, SFES is introduced to solve the voltage drop under the low voltage distribution system by using the concept of the proposed DC OLEV which results in building the longer distance power supply system. The simulation to design the SFES by using DC power flow analysis is carried out and it is verified in this paper.

  6. Improvement of burst-mode control of piezoelectric transformer based DC/DC converter

    NASA Astrophysics Data System (ADS)

    Vasic, Dejan; Liu, Yuan-Ping; Schwander, Denis; Costa, François; Wu, Wen-Jong

    2013-05-01

    Burst-mode operation is adopted sometimes in piezoelectric transformer based converters for two major purposes: (1) to achieve voltage regulation in DC/DC converters and (2) to achieve dimming control in backlight inverters. Burst-mode control enables the converter to operate at a constant switching frequency as well as to maintain good efficiency at light load conditions. However, in practice, the piezoelectric transformer cannot instantly stop vibrating in the burst-mode due to its high quality factor. The delay in the output voltage change resulting from this behavior influences the accuracy of the regulation. This paper proposes a control strategy to make the piezoelectric transformer stop more quickly so as to enhance the accuracy of burst-mode control. The proposed method only modifies the control signal of the burst-mode driving circuit. The proposed control strategy is verified by experiments in a step-down 9 W DC/DC converter.

  7. 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.

  8. ELRIS2D: A MATLAB Package for the 2D Inversion of DC Resistivity/IP Data

    NASA Astrophysics Data System (ADS)

    Akca, Irfan

    2016-04-01

    ELRIS2D is an open source code written in MATLAB for the two-dimensional inversion of direct current resistivity (DCR) and time domain induced polarization (IP) data. The user interface of the program is designed for functionality and ease of use. All available settings of the program can be reached from the main window. The subsurface is discretized using a hybrid mesh generated by the combination of structured and unstructured meshes, which reduces the computational cost of the whole inversion procedure. The inversion routine is based on the smoothness constrained least squares method. In order to verify the program, responses of two test models and field data sets were inverted. The models inverted from the synthetic data sets are consistent with the original test models in both DC resistivity and IP cases. A field data set acquired in an archaeological site is also used for the verification of outcomes of the program in comparison with the excavation results.

  9. 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.

  10. Border Collision of Three-Phase Voltage-Source Inverter System with Interacting Loads

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Liu, Bin; Li, Yining; Wong, Siu-Chung; Liu, Xiangdong; Huang, Yuehui

    As a commercial interface, three-phase voltage-source inverters (VSI) are commonly equipped for energy conversion to export DC power from most distributed generation (DG) to the AC utility. Not only do voltage-source converters take charge of converting the power to the loads but support the grid voltage at the point of common connection (PCC) as well, which is dependent on the condition of the grid-connected loads. This paper explores the border collision and its interacting mechanism among the VSI, resistive interacting loads and grids, which manifests as the alternating emergence of the inverting and rectifying operations, where the normal operation is terminated and a new one is assumed. Their mutual effect on the power quality under investigation will cause the circuital stability issue and further deteriorate the voltage regulation capability of VSI by dramatically raising the grid voltage harmonics. It is found in a design-oriented view that the border collision operation will be induced within the unsuitable parameter space with respect to transmission lines of AC grid, resistive loads and internal resistance of VSI. The physical phenomenon is also identified by the theoretical analysis. With numerical simulations for various circuit conditions, the corresponding bifurcation boundaries are collected, where the stability of the system is lost via border collision.

  11. Rhenium Disulfide Depletion-Load Inverter

    NASA Astrophysics Data System (ADS)

    McClellan, Connor; Corbet, Chris; Rai, Amritesh; Movva, Hema C. P.; Tutuc, Emanuel; Banerjee, Sanjay K.

    2015-03-01

    Many semiconducting Transition Metal Dichalcogenide (TMD) materials have been effectively used to create Field-Effect Transistor (FET) devices but have yet to be used in logic designs. We constructed a depletion-load voltage inverter using ultrathin layers of Rhenium Disulfide (ReS2) as the semiconducting channel. This ReS2 inverter was fabricated on a single micromechanically-exfoliated flake of ReS2. Electron beam lithography and physical vapor deposition were used to construct Cr/Au electrical contacts, an Alumina top-gate dielectric, and metal top-gate electrodes. By using both low (Aluminum) and high (Palladium) work-function metals as two separate top-gates on a single ReS2 flake, we create a dual-gated depletion mode (D-mode) and enhancement mode (E-mode) FETs in series. Both FETs displayed current saturation in the output characteristics as a result of the FET ``pinch-off'' mechanism and On/Off current ratios of 105. Field-effect mobilities of 23 and 17 cm2V-1s-1 and subthreshold swings of 97 and 551 mV/decade were calculated for the E-mode and D-mode FETs, respectively. With a supply voltage of 1V, at low/negative input voltages the inverter output was at a high logic state of 900 mV. Conversely with high/positive input voltages, the inverter output was at a low logic state of 500 mV. The inversion of the input signal demonstrates the potential for using ReS2 in future integrated circuit designs and the versatility of depletion-load logic devices for TMD research. NRI SWAN Center and ARL STTR Program.

  12. Inverter Ground Fault Overvoltage Testing

    SciTech Connect

    Hoke, Andy; Nelson, Austin; Chakraborty, Sudipta; Chebahtah, Justin; Wang, Trudie; McCarty, Michael

    2015-08-12

    This report describes testing conducted at NREL to determine the duration and magnitude of transient overvoltages created by several commercial PV inverters during ground fault conditions. For this work, a test plan developed by the Forum on Inverter Grid Integration Issues (FIGII) has been implemented in a custom test setup at NREL. Load rejection overvoltage test results were reported previously in a separate technical report.

  13. Triple inverter pierce oscillator circuit suitable for CMOS

    DOEpatents

    Wessendorf; Kurt O.

    2007-02-27

    An oscillator circuit is disclosed which can be formed using discrete field-effect transistors (FETs), or as a complementary metal-oxide-semiconductor (CMOS) integrated circuit. The oscillator circuit utilizes a Pierce oscillator design with three inverter stages connected in series. A feedback resistor provided in a feedback loop about a second inverter stage provides an almost ideal inverting transconductance thereby allowing high-Q operation at the resonator-controlled frequency while suppressing a parasitic oscillation frequency that is inherent in a Pierce configuration using a "standard" triple inverter for the sustaining amplifier. The oscillator circuit, which operates in a range of 10 50 MHz, has applications for use as a clock in a microprocessor and can also be used for sensor applications.

  14. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an aqueous solution of inverted...

  15. Dual wound dc brush motor gearhead

    NASA Technical Reports Server (NTRS)

    Henson, Barrie W.

    1986-01-01

    The design requirements, the design, development tests and problems, the qualification and life test and the findings of the strip examination of a dual wound DC brushed motor gearhead are described. It is the only space qualified dual wound dc brushed motor gearhead in Europe.

  16. Cascaded H-bridge multilevel inverter for renewable energy generation

    NASA Astrophysics Data System (ADS)

    Pandey, Ravikant; Nath Tripathi, Ravi; Hanamoto, Tsuyoshi

    2016-04-01

    In this paper cascaded H-bridge multilevel inverter (CHBMLI) has been investigated for the application of renewable energy generation. Energy sources like solar, wind, hydro, biomass or combination of these can be manipulated to obtain alternative sources for renewable energy generation. These renewable energy sources have different electrical characteristics like DC or AC level so it is challenging to use generated power by connecting to grid or load directly. The renewable energy source require specific power electronics converter as an interface for conditioning generated power .The multilevel inverter can be utilized for renewable energy sources in two different modes, the power generation mode (stand-alone mode), and compensator mode (statcom). The performance of the multilevel inverter has been compared with two level inverter. In power generation mode CHBMLI supplies the active and reactive power required by the different loads. For operation in compensator mode the indirect current control based on synchronous reference frame theory (SRFT) ensures the grid operating in unity power factor and compensate harmonics and reactive power.

  17. DC CICC retrofit magnet preliminary design, software development and analysis report. Quarterly progress report, [January 1, 1992--March 31, 1992

    SciTech Connect

    Myatt, R.L.; Marston, P.G.

    1992-05-28

    The January 1992 quarterly progress report discusses a two-dimensional finite element analysis (FEA) of the proposed retrofit MHD coil. The superconducting Cable-in-Conduit Conductor (CICC) winding pack has a smooth, semi-elliptical cross section and is supported by a similarly shaped strap which resists the electromagnetic forces tending to separate the coils on each side of the channel. The coils are designed to produce a peak on-axis field of 4.5 tesla with a nominal current density of 13.05{times}10{sup 6} A/m{sup 2}. A sketch of the magnet system and structure is shown in Fig. 1.0-1. The objective of this analysis is to quantify the highly 3-D characteristics of the proposed superconductivity magnet system, and develop an appropriate support concept. A fully paramatized 3-D finite element model of the coil and structure is developed as a means of obtaining the field and stress solutions. The flexibility of FEA and a model built using design parameters allows variations in the coil end turn bend radius, strap thickness, support details and positions to be studied. The preliminary results show the calculated stresses as a result of this iterative design process.

  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. 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.

  1. 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.

  2. 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.

  3. Modified Dual Three-Pulse Modulation technique for single-phase inverter topology

    NASA Astrophysics Data System (ADS)

    Sree Harsha, N. R.; Anitha, G. S.; Sreedevi, A.

    2016-01-01

    In a recent paper, a new modulation technique called Dual Three Pulse Modulation (DTPM) was proposed to improve the efficiency of the power converters of the Electric/Hybrid/Fuel-cell vehicles. It was simulated in PSIM 9.0.4 and uses analog multiplexers to generate the modulating signals for the DC/DC converter and inverter. The circuit used is complex and many other simulation softwares do not support the analog multiplexers as well. Also, the DTPM technique produces modulating signals for the converter, which are essentially needed to produce the modulating signals for the inverter. Hence, it cannot be used efficiently to switch the valves of a stand-alone inverter. We propose a new method to generate the modulating signals to switch MOSFETs of a single phase Dual-Three pulse Modulation based stand-alone inverter. The circuits proposed are simulated in Multisim 12.0. We also show an alternate way to switch a DC/DC converter in a way depicted by DTPM technique both in simulation (MATLAB/Simulink) and hardware. The circuitry is relatively simple and can be used for the further investigations of DTPM technique.

  4. Design of an input filter for power factor correction (PFC) AC to DC converters employing an active ripple cancellation

    SciTech Connect

    Lee, D.Y.; Cho, B.H.

    1996-12-31

    An active input filter for power factor correction (PFC) circuit employing ripple current cancellation is proposed to reduce the filter`s size and cost.Switching ripple current can be filtered by an active circuit from the line current. A single stage passive filter with the active filter compensation circuit, a high filter can be synthesized to meet the electromagnetic interference (EMI) and power factor requirements. Analysis of the active filter and design procedure are detailed. Simulation result is presented to verify the high order filter characteristics of proposed scheme.

  5. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    DOEpatents

    Pitel, I.J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage. 19 figs.

  6. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    DOEpatents

    Pitel, Ira J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage.

  7. Inverter-based GTA welding machines improve fabrication

    SciTech Connect

    Sammons, M.

    2000-05-01

    While known as precision process, many fabricators using the gas tungsten arc welding (GTAW) process fight several common problems that hinder quality, slow production, frustrate the operator and otherwise prevent the process from achieving its full potential. These include a limited ability to tailor the weld bead profile, poor control of the arc direction and arc wandering, poor arc starting, unstable or inconsistent arcs in the AC mode, high-frequency interference with electronics and tungsten contamination. Fortunately, new GTA welding technology--made possible by advances with inverter-based power sources and micro-processor controls--can eliminate common productivity gremlins. Further, new AC/DC inverter-based GTA power sources provide advanced arc shaping capabilities. As a result, many fabricators adopting this new technology have experienced phenomenal production increases, taken on new types of projects and reduced costs. Most importantly, the operators enjoy welding more.

  8. 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.

  9. Motor control for a brushless DC motor

    NASA Technical Reports Server (NTRS)

    Peterson, William J. (Inventor); Faulkner, Dennis T. (Inventor)

    1985-01-01

    This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed. A fundamental current waveform phase advance circuit is controllingly coupled to the inverter. The phase advance circuit is coupled to receive the pulsed waveform signal from the motor rotor speed detecting unit and phase advance the pulsed waveform signal as a predetermined function of motor speed to thereby cause the fundamental current waveform to be advanced and thereby compensate for fundamental current waveform lag due to motor winding reactance which allows the motor to operate at higher speeds than the motor is rated while providing optimal torque and therefore increased efficiency.

  10. 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.

  11. High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs

    DOEpatents

    Shimer, D.W.; Lange, A.C.

    1995-05-23

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

  12. High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

    DOEpatents

    Shimer, Daniel W.; Lange, Arnold C.

    1995-01-01

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

  13. Development of a New Class of Low Cost, High Frequency Link Direct DC to AC Converters for Solid Oxide Fuel Cells (SOFC)

    SciTech Connect

    Prasad Enjeti; J.W. Howze

    2003-12-01

    This project proposes to design and develop a new class of power converters (direct DC to AC) to drastically improve performance and optimize the cost, size, weight and volume of the DC to AC converter in SOFC systems. The proposed topologies employ a high frequency link; direct DC to AC conversion approach. The direct DC to AC conversion approach is more efficient and operates without an intermediate dc-link stage. The absence of the dc-link, results in the elimination of bulky, aluminum electrolytic capacitors, which in turn leads to a reduction in the cost, volume, size and weight of the power electronic converter. The feasibility of two direct DC to AC converter topologies and their suitability to meet SECA objectives will be investigated. Laboratory proto-type converters (3-5kW) will be designed and tested in Phase-1. A detailed design trade-off study along with the test results will be available in the form of a report for the evaluation of SECA Industrial partners. This project proposes to develop a new and innovative power converter technology suitable for Solid Oxide Fuel Cell (SOFC) power systems in accordance with SECA objectives. The proposed fuel cell inverter (FCI) employs state of the art power electronic devices configured in two unique topologies to achieve direct conversion of DC power (24-48V) available from a SOFC to AC power (120/240V, 60Hz) suitable for utility interface and powering stand alone loads. The primary objective is to realize cost effective fuel cell converter, which operates under a wide input voltage range, and output load swings with high efficiency and improved reliability.

  14. Novel Multiple DC-Inputs Direct Electric-Power Converter

    NASA Astrophysics Data System (ADS)

    Yoshimoto, Kantaro; Takahashi, Kouji; Okushima, Keiji; Tani, Kazuhiko

    A new multiple dc-inputs direct electric-power converter (D-EPC) has been developed. It is placed between multiple dc power sources and an ac motor, thereby eliminating the need for a dc/dc converter that is generally used in conventional converter/inverter systems. D-PEC can improve the efficiency of a motor drive system with a more compact size. Its power distribution control is carried out by allotting voltage ratios to each of the two different dc power sources on a time average basis. A new pulse width modulation (PWM) generation technique to drive the switching devices in D-EPC has also been developed. Tests have verified that the three-phase ac motor can be operated by controlling the power distribution between the two power sources.

  15. Relationships among classes of self-oscillating transistor parallel inverters. [for power conditioning applications

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    It recently has been shown in the literature that many dc-to-square-wave parallel inverters which are widely used in power-conditioning applications can be grouped into one of two families. Each family is characterized by an equivalent RLC network. Based on this approach, a classification procedure is presented for self-oscillating parallel inverters which makes evident natural relationships which exist between various inverter configurations. By utilizing concepts from the basic theory of negative resistance oscillators and the principle of duality as applied to nonlinear networks, a chain of relationships is established which enables a methodical transfer of knowledge gained about one family of inverters to any of the other families in the classification array.

  16. Inverters for interfacing of solar cells with the power grid

    NASA Astrophysics Data System (ADS)

    Karamanzanis, G. N.; Jackson, R. D.

    In this work, based on a research course in the Engineering Dep. Cambridge University, some non-classical inverter circuits are studied. They can be used for interfacing solar cells with the power grid at low voltage (230V) and at low power level. They are based on d.c. choppers which have a fast switching transistor. Their theoretical efficiency is 100 percent and they provide a satisfactory output current waveform in phase to the a.c. line voltage. The problems of control are also studied using a suitable mathematical model.

  17. An Inverter Packaging Scheme for an Integrated Segmented Traction Drive System

    SciTech Connect

    Su, Gui-Jia; Tang, Lixin; Ayers, Curtis William; Wiles, Randy H

    2013-01-01

    The standard voltage source inverter (VSI), widely used in electric vehicle/hybrid electric vehicle (EV/HEV) traction drives, requires a bulky dc bus capacitor to absorb the large switching ripple currents and prevent them from shortening the battery s life. The dc bus capacitor presents a significant barrier to meeting inverter cost, volume, and weight requirements for mass production of affordable EVs/HEVs. The large ripple currents become even more problematic for the film capacitors (the capacitor technology of choice for EVs/HEVs) in high temperature environments as their ripple current handling capability decreases rapidly with rising temperatures. It is shown in previous work that segmenting the VSI based traction drive system can significantly decrease the ripple currents and thus the size of the dc bus capacitor. This paper presents an integrated packaging scheme to reduce the system cost of a segmented traction drive.

  18. Commercial Of-The Shelf DC/DC Converter

    NASA Astrophysics Data System (ADS)

    Denzinger, W.; Baumel, S.

    2011-10-01

    A commercial of-the-shelf (COTS) DC/DC converter for the supply of digital electronics on board of spacecraft has been developed with special emphasis on: *Low cost Readily available *Easy manufacturing *No use of ITAR listed EEE parts like rad-hard mosfets *Minimum number of rad-hard digital and analog IC's *Design tolerance against SEE by appropriate filtering The study was supported by the European Space Agency (ESA) under the contract number 21729/08/NL7LvH.

  19. 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.

  20. Generation and Characterization of Magnetized Bunched Electron Beam from a DC High Voltage Photogun

    NASA Astrophysics Data System (ADS)

    Suleiman, Riad; Poelker, Matthew; Benesch, Jay; Hannon, Fay; Hernandez-Garcia, Carlos; Wang, Yan

    2016-03-01

    To maintain ion beam emittance and extend luminosity lifetime, the Jefferson Lab design of the Electron Ion Collider includes a bunched magnetized electron beam cooler as part of the Collider Ring. We are building a prototype magnetized gun using our newly commissioned 325 kV inverted-insulator DC high voltage photogun. This contribution describes planned measurements of beam magnetization as a function of bunch charge and average current, and laser beam size and magnetic field strength at the photocathode. Results will be compared to particle tracking code simulations. Photocathode lifetime at milli-ampere current will be compared to beam lifetime with no magnetization, to explore the impact of the magnetic field on photogun operation. Combined, these measurements and simulations will benchmark our design tools and provide insights on ways to optimize the electron cooler. This work is supported by the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC05-06OR23177.

  1. 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.

  2. Inverting an Introductory Statistics Classroom

    ERIC Educational Resources Information Center

    Kraut, Gertrud L.

    2015-01-01

    The inverted classroom allows more in-class time for inquiry-based learning and for working through more advanced problem-solving activities than does the traditional lecture class. The skills acquired in this learning environment offer benefits far beyond the statistics classroom. This paper discusses four ways that can make the inverted…

  3. Overload protection system for power inverter

    NASA Technical Reports Server (NTRS)

    Nagano, S. (Inventor)

    1977-01-01

    An overload protection system for a power inverter utilized a first circuit for monitoring current to the load from the power inverter to detect an overload and a control circuit to shut off the power inverter, when an overload condition was detected. At the same time, a monitoring current inverter was turned on to deliver current to the load at a very low power level. A second circuit monitored current to the load, from the monitoring current inverter, to hold the power inverter off through the control circuit, until the overload condition was cleared so that the control circuit may be deactivated in order for the power inverter to be restored after the monitoring current inverter is turned off completely.

  4. 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.

  5. Update on SIC-Based Inverter Technology

    SciTech Connect

    Chinthavali, Madhu Sudhan; Zhang, Hui; Tolbert, Leon M; Ozpineci, Burak

    2009-01-01

    This paper presents a study of silicon carbide (SiC) technology which includes device characterization and modeling, inverter simulation, and test results for several prototype inverters. The static and dynamic characteristics of discrete devices and half bridge modules are presented. Test results of a 55 kW hybrid inverter with SiC Schottky diodes and an 18 kW all-SiC inverter using SiC JFETs and Schottky diodes are demonstrated.

  6. Improved Performance via the Inverted Classroom

    ERIC Educational Resources Information Center

    Weinstein, Randy D.

    2015-01-01

    This study examined student performance in an inverted thermodynamics course (lectures provided by video outside of class) compared to a traditional lecture class. Students in the inverted class performed better on their exams. Students in the bottom third of the inverted course showed the greatest improvement. These bottom third students had a C…

  7. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  8. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  9. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  10. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  11. Inverted Teaching: Applying a New Pedagogy to a University Organic Chemistry Class

    ERIC Educational Resources Information Center

    Christiansen, Michael A.

    2014-01-01

    Inverted teaching, not to be confused with hybrid learning, is a relatively new pedagogy in which lecture is shifted outside of class and traditional homework is done in class. Though some inverted teaching (IT) designs have been published in different fields, peer-reviewed reports in university chemistry remain quite rare. To that end, herein is…

  12. A dc Penning surface-plasma source

    SciTech Connect

    Smith, H.V. Jr.; Allison, P.; Geisik, C.; Schmitt, D.R.; Schneider, J.D.; Stelzer, J.E.

    1993-09-01

    After developing a pulsed-8X source for H{sup {minus}} beams, we are now testing a cooled, dc version. The design dc power density on the cathode surface is 900 W/cm{sup 2}, much higher than achieved in any previously-reported Penning surface-plasma source (SPS). The source is designed to accommodate dc arc power levels up to 30 kW by cooling the electrode surfaces with pressurized, hot water. After striking the arc using a 600-V pulser, a 350-V dc power supply is switched in to sustain the 100-V discharge. Now our tests are concentrating on arc pulse lengths {le}1 s. Ultimately, the discharge will be operated dc. The source is described and the initial arc test results are presented.

  13. Piezometer completion report for borehole cluster sites DC-19, DC-20, and DC-22

    SciTech Connect

    Jackson, R.L.; Diediker, L.D.; Ledgerwood, R.K.; Veatch, M.D.

    1984-07-01

    This report describes the design and installation of multi-level piezometers at borehole cluster sites DC-19, DC-20 and DC-22. The network of borehole cluster sites will provide facilities for multi-level water-level monitoring across the RRL for piezometer baseline monitoring and for large-scale hydraulic stress testing. These groundwater-monitoring facilities were installed between August 1983 and March 1984. Three series of piezometer nests (A-, C- and D-series) were installed in nine hydrogeologic units (monitoring horizons) within the Columbia River Basalt Group at each borehole cluster site. In addition to the piezometer facilities, a B-series pumping well was installed at borehole cluster sites DC-20 and DC-22. The A-series piezometer nest monitors the basal Ringold sediments and the Rattlesnake Ridge interbed. The C-series piezometer nests monitors the six deepest horizons, which are in increasing depth, the Priest Rapids interflow, Sentinel Gap flow top, Ginkgo flow top, Rocky Coulee flow top, Cohassett flow top and Umtanum flow top. The D-series piezometer monitors the Mabton interbed. The B-series pumping well was completed in the Priest Rapids interflow. 21 refs., 6 figs., 6 tabs.

  14. 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.

  15. Processing of Inverted Files in Magnetic Bubble Memories.

    ERIC Educational Resources Information Center

    Zaki, M.; Elboraey, F.

    1985-01-01

    Investigates applicability of inverted file processing in magnetic bubble memories by presenting four magnetic bubble memory models as storage mediums: one based on a major-minor loop configuration; one utilizing a decoder design on a magnetic bubble memory chip; and two based on different structural configurations of the first two. (MBR)

  16. Regenerative Snubber For GTO-Commutated SCR Inverter

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E.; Edwards, Dean B.

    1992-01-01

    Proposed regenerative snubbing circuit substituted for dissipative snubbing circuit in inverter based on silicon controlled rectifiers (SCR's) commutated by gate-turn-off thyristor (GTO). Intended to reduce loss of power that occurs in dissipative snubber. Principal criteria in design: low cost, simplicity, and reliability.

  17. Robust DC/DC converter control for polymer electrolyte membrane fuel cell application

    NASA Astrophysics Data System (ADS)

    Wang, Ya-Xiong; Yu, Duck-Hyun; Chen, Shi-An; Kim, Young-Bae

    2014-09-01

    This study investigates a robust controller in regulating the pulse width modulation (PWM) of a DC/DC converter for a polymer electrolyte membrane fuel cell (PEMFC) application. A significant variation in the output voltage of a PEMFC depends on the power requirement and prevents a PEMFC from directly connecting to a subsequent power bus. DC/DC converters are utilized to step-up or step-down voltage to match the subsequent power bus voltage. In this study, a full dynamic model, which includes a PEMFC and boost and buck DC/DC converters, is developed under MATLAB/Simulink environment for control. A robust PWM duty ratio control for the converters is designed using time delay control (TDC). This control enables state variables to accurately follow the dynamics of a reference model using time-delayed information of plant input and output information within a few sampling periods. To prove the superiority of the TDC performance, traditional proportional-integral control (PIC) and model predictive control (MPC) are designed and implemented, and the simulation results are compared. The efficacies of TDC for the PEMFC-fed PWM DC/DC converters are validated through experimental test results using a 100 W PEMFC as well as boost and buck DC/DC converters.

  18. Thermal Study of Inverter Components: Preprint

    SciTech Connect

    Sorensen, N. R.; Thomas, E. V.; Quintana, M. A.; Barkaszi, S.; Rosenthal, A.; Zhang, Z.; Kurtz, S.

    2012-06-01

    Thermal histories of inverter components were collected from operating inverters from several manufacturers and three locations. The data were analyzed to determine thermal profiles, the dependence on local conditions, and to assess the effect on inverter reliability. Inverter temperatures were shown to increase with the power dissipation of the inverters, follow diurnal and annual cycles, and have a dependence on wind speed. An accumulated damage model was applied to the temperature profiles and an example of using these data to predict reliability was explored.

  19. Three-phase multilevel solar inverter for motor drive system

    NASA Astrophysics Data System (ADS)

    Bhasagare, Mayuresh P.

    This thesis deals with three phase inverters and the different control strategies that can be associated with an inverter being used together. The first part of this thesis discusses the present research in the fields of PV panels, motor drive systems and three phase inverters along with their control. This control includes various strategies like MPPT, Volts-Hertz and modulation index compensation. Incorporating these techniques together is the goal of this thesis. A new topology for operating an open end motor drive system has also been discusses, where a boost converter and a flyback converter have been used in cascade to run a three phase motor. The main advantage of this is increasing the number of levels and improving the quality of the output voltage, not to mention a few other benefits of having the proposed circuit. A new algorithm has also been designed for starting and stopping the motor, which controls the current drawn from the power source during starting.

  20. Suspended Patch Antenna Array With Electromagnetically Coupled Inverted Microstrip Feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2000-01-01

    The paper demonstrates a four-element suspended patch antenna array, with a parasitic patch layer and an electromagnetically coupled inverted microstrip feed, for linear polarization at K-Band frequencies. This antenna has the following advantages over conventional microstrip antennas: First, the inverted microstrip has lower attenuation than conventional microstrip; hence, conductor loss associated with the antenna corporate feed is lower resulting in higher gain and efficiency. Second, conventional proximity coupled patch antennas require a substrate for the feed and a superstrate for the patch. However, the inverted microstrip fed patch antenna makes use of a single substrate, and hence, is lightweight and low cost. Third, electromagnetic coupling results in wider bandwidth. Details regarding the design and fabrication will be presented as well as measured results including return loss, radiation patterns and cross-polarization levels.

  1. A Novel Current Angle Control Scheme in a Current Source Inverter Fed Permanent Magnet Synchronous Motor Drive for Automotive Applications

    SciTech Connect

    Tang, Lixin; Su, Gui-Jia

    2011-01-01

    This paper describes a novel speed control scheme to operate a current source inverter (CSI) driven surface-mounted permanent magnet synchronous machine (SPMSM) for hybrid electric vehicles (HEVs) applications. The idea is to use the angle of the current vector to regulate the rotor speed while keeping the two dc-dc converter power switches on all the time to boost system efficiency. The effectiveness of the proposed scheme was verified with a 3 kW CSI-SPMSM drive prototype.

  2. Linear control of the flywheel inverted pendulum.

    PubMed

    Olivares, Manuel; Albertos, Pedro

    2014-09-01

    The flywheel inverted pendulum is an underactuated mechanical system with a nonlinear model but admitting a linear approximation around the unstable equilibrium point in the upper position. Although underactuated systems usually require nonlinear controllers, the easy tuning and understanding of linear controllers make them more attractive for designers and final users. In a recent paper, a simple PID controller was proposed by the authors, leading to an internally unstable controlled plant. To achieve global stability, two options are developed here: first by introducing an internal stabilizing controller and second by replacing the PID controller by an observer-based state feedback control. Simulation and experimental results show the effectiveness of the design. PMID:24480638

  3. HOLLOTRON switch for megawatt lightweight space inverters

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.; Goebel, D. M.; Schumacher, R. W.

    1991-01-01

    The feasibility of satisfying the switching requirements for a megawatt ultralight inverter system using HOLLOTRON switch technology was determined. The existing experimental switch hardware was modified to investigate a coaxial HOLLOTRON switch configuration and the results were compared with those obtained for a modified linear HOLLOTRON configuration. It was concluded that scaling the HOLLOTRON switch to the current and voltage specifications required for a megawatt converter system is indeed feasible using a modified linear configuration. The experimental HOLLOTRON switch operated at parameters comparable to the scaled coaxial HOLLOTRON. However, the linear HOLLOTRON data verified the capability for meeting all the design objectives simultaneously including current density (greater than 2 A/sq cm), voltage (5 kV), switching frequency (20 kHz), switching time (300 ns), and forward voltage drop (less than or equal to 20 V). Scaling relations were determined and a preliminary design was completed for an engineering model linear HOLLOTRON switch to meet the megawatt converter system specifications.

  4. The Inverted Snow Globe Shadow

    NASA Astrophysics Data System (ADS)

    Ribeiro, Jair Lúcio Prados

    2015-01-01

    Our high school optics course finishes with an assignment that students usually appreciate. They must take pictures of everyday situations representing optical phenomena such as reflection, refraction, or dispersion, and post them on Instagram.1 When the photos were presented to the class, one student revealed an intriguing photo, similar to Fig. 1, showing a snow globe exposed to sunlight and its inverted shadow. This paper offers an explanation of the problem, which occurs due to light refraction from the globe.

  5. Test Report on ISR Double-Loop, Spray-Cooled Inverter

    SciTech Connect

    Hsu, John S; Coomer, Chester; Campbell, Steven L; Wiles, Randy H; Lowe, Kirk T; McFee, Marshall T

    2007-02-01

    The Isothermal Systems Research, Inc. (ISR) double-loop, two-phase spray cooling system was designed to use 85 C transmission oil to cool a heat exchanger via a second cooling loop. The heat exchanger condenses the working fluid vapor back to liquid inside a sealed enclosure to allow for continuous spray cooling of electronics. In the ORNL tests, 85 C water/ethylene/glycol (WEG), which has better thermal properties than transmission oil, was substituted for the transmission oil. Because the ISR spray-cooling system requires a second cooling loop, the final inverter might be inherently larger than inverters that do not require a second-loop cooling system. The ISR test setup did not include a dc bus capacitor. Because the insulated gate bipolar transistor (IGBT) conduction test indicated that the ISR test setup could not be properly loaded thermally, no switching tests were conducted. Therefore it was not necessary to attach external capacitors outside the test setup. During load situations not exceeding 400A, the WEG inlet temperature was higher than the WEG outlet temperature. This meant that the 85 C WEG heat exchanger was not cooling the inverter and became a thermal load to the inverter. Only when the load was higher than 400A with a higher coolant temperature and the release valve actuated did the WEG heat exchanger start to cool the 2-phase coolant. The inverter relied strongly on the cooling of the huge aluminum enclosure located inside the ventilation chamber. In a hybrid vehicle, the inverter is situated under the hood, where the dependency on cooling provided by the enclosure may become a problem. The IGBT power dissipation with both sides being spray cooled was around 34 W/cm{sup 2} at 403A, with 995W total IGBT loss at 113.5 C projected junction temperature before the release valve was actuated. The current loading could rise higher than 403 A before reaching the 125 C junction temperature limit if the pressure buildup inside the enclosure could be

  6. Gripper deploying and inverting linkage

    DOEpatents

    Minichan, Richard L.; Killian, Mark A.

    1993-01-01

    An end effector deploying and inverting linkage. The linkage comprises an air cylinder mounted in a frame or tube, a sliding bracket next to the air cylinder, a stopping bracket depending from the frame and three, pivotally-attached links that are attached to the end effector and to each other in such a way as to be capable of inverting the end effector and translating it laterally. The first of the three links is a straight element that is moved up and down by the shaft of the air cylinder. The second link is attached at one end to the stopping bracket and to the side of the end effector at the other end. The first link is attached near the middle of the second, sharply angled link so that, as the shaft of the air cylinder moves up and down, the second link rotates about an axis perpendicular to the frame and inverts and translates the end effector. The rotation of the second link is stopped at both ends when the link engages stops on the stopping bracket. The third link, slightly angled, is attached to the sliding bracket at one end and to the end of the end effector at the other. The third helps to control the end effector in its motion.

  7. Gripper deploying and inverting linkage

    DOEpatents

    Minichan, R.L.; Killian, M.A.

    1993-03-02

    An end effector deploying and inverting linkage. The linkage comprises an air cylinder mounted in a frame or tube, a sliding bracket next to the air cylinder, a stopping bracket depending from the frame and three, pivotally-attached links that are attached to the end effector and to each other in such a way as to be capable of inverting the end effector and translating it laterally. The first of the three links is a straight element that is moved up and down by the shaft of the air cylinder. The second link is attached at one end to the stopping bracket and to the side of the end effector at the other end. The first link is attached near the middle of the second, sharply angled link so that, as the shaft of the air cylinder moves up and down, the second link rotates about an axis perpendicular to the frame and inverts and translates the end effector. The rotation of the second link is stopped at both ends when the link engages stops on the stopping bracket. The third link, slightly angled, is attached to the sliding bracket at one end and to the end of the end effector at the other. The third helps to control the end effector in its motion.

  8. Improvement on an inverted decoupling technique for a class of stable linear multivariable processes.

    PubMed

    Chen, Peiying; Zhang, Weidong

    2007-04-01

    This paper improves an inverted decoupling technique for a class of stable linear multivariable processes with multiple time delays and nonminimum-phase zeros. Two decoupling schemes are proposed based on the inverted decoupling technique. One is a developed inverted decoupling scheme. In this scheme, the decoupler is designed such that the inverted decoupling technique accommodates a wider field than the one introduced in the published literature. However, due to the stability issue, some multivariable processes still cannot be decoupled by the inverted decoupling structure. To solve this problem, another modified decoupling scheme with unity feedback structure is suggested for implementation. The Internal Model Control (IMC) theory is applied here to design PI/PID controllers for the decoupled processes. Furthermore, in the presence of multiplicative input uncertainty, low bounds of the control parameters are derived quantitatively for guaranteeing robust stability of the system. Simulations are illustrated for demonstrating the validity of the proposed control schemes. PMID:17343860

  9. Advances in series resonant inverter technology and its effect on spacecraft employing electric propulsion

    NASA Technical Reports Server (NTRS)

    Robson, R. R.

    1982-01-01

    The efficiency of transistorized Series Resonant Inverters (SRIs), which is higher than that of silicon-controlled rectifier alternatives, reduces spacecraft radiator requirements by 40% and may eliminate the need for heat pipes on 30-cm ion thruster systems. Recently developed 10- and 25-kW inverters have potential applications in gas thrusters, and represent the first spaceborne SRI designs for such power levels. Attention is given to the design and control system approaches employed in these inverter designs to improve efficiency and reduce weight, along with the impact of such improved parameters on electric propulsion systems.

  10. Development of a surface micro-machined binary logic inverter for ultra-low frequency MEMS sensor applications

    NASA Astrophysics Data System (ADS)

    Chakraborty, S.; Bhattacharyya, T. K.

    2010-10-01

    This paper presents the development of surface micro-machined binary logic inverter for implementation in low-frequency signal processing applications in MEMS-based sensors. The micro-cantilever switch, which is the fundamental building block of the design, has been designed and optimized with an analytical method and validated with simulation. The working principle of the inverter has been comprehensively worked out. A thorough detail of the design and performance analysis of the inverter has been carried out and it has been verified using system level simulation. The PolyMUMPs surface micro-machining process has been used for implementing and fabricating the MEMS-based digital inverter. The mechanical response and the switching response of the beams used in the inverter have been extensively investigated. Thorough static and dynamic functional characterizations have been carried out on the inverter.

  11. Design of Value-Added Models for IMPACT and TEAM in DC Public Schools, 2010-2011 School Year. Final Report

    ERIC Educational Resources Information Center

    Isenberg, Eric; Hock, Heinrich

    2011-01-01

    This report presents the value-added models that will be used to measure school and teacher effectiveness in the District of Columbia Public Schools (DCPS) in the 2010-2011 school year. It updates the earlier technical report, "Measuring Value Added for IMPACT and TEAM in DC Public Schools." The earlier report described the methods used…

  12. 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.

  13. An Optically Controllable Transformation-dc Illusion Device.

    PubMed

    Jiang, Wei Xiang; Luo, Chen Yang; Ge, Shuo; Qiu, Cheng-Wei; Cui, Tie Jun

    2015-08-19

    The concept of multifunctional transformation-dc devices is proposed and verified experimentally. The functions of dc metamaterials can be remotely altered by illuminating with visible light. If the light-induced dc illusion effect is activated, the electrostatic behavior of the original object is perceived as multiple equivalent objects with different pre-designed geometries. The experimental verification of the functional device makes it possible to control sophisticated transformation-dc devices with external light illumination. PMID:26177597

  14. 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.

  15. Analysis of high voltage step-up nonisolated DC-DC boost converters

    NASA Astrophysics Data System (ADS)

    Alisson Alencar Freitas, Antônio; Lessa Tofoli, Fernando; Junior, Edilson Mineiro Sá; Daher, Sergio; Antunes, Fernando Luiz Marcelo

    2016-05-01

    A high voltage step-up nonisolated DC-DC converter based on coupled inductors suitable to photovoltaic (PV) systems applications is proposed in this paper. Considering that numerous approaches exist to extend the voltage conversion ratio of DC-DC converters that do not use transformers, a detailed comparison is also presented among the proposed converter and other popular topologies such as the conventional boost converter and the quadratic boost converter. The qualitative analysis of the coupled-inductor-based topology is developed so that a design procedure can be obtained, from which an experimental prototype is implemented to validate the theoretical assumptions.

  16. 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.

  17. 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.

  18. Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1

    NASA Technical Reports Server (NTRS)

    Lee, F. C.; Mahmoud, M. F.; Yu, Y.

    1980-01-01

    The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

  19. Critical conditions of saddle-node bifurcations in switching DC-DC converters

    NASA Astrophysics Data System (ADS)

    Fang, Chung-Chieh

    2013-08-01

    Although existence of multiple periodic orbits in some DC-DC converters have been known for decades, linking the multiple periodic orbits with the saddle-node bifurcation (SNB) is rarely reported. The SNB occurs in popular DC-DC converters, but it is generally reported as a strange instability. Recently, design-oriented instability critical conditions are of great interest. In this article, average, sampled-data and harmonic balance analyses are applied and they lead to equivalent results. Many new critical conditions are derived. They facilitate future research on the instability associated with multiple periodic orbits, sudden voltage jumps or disappearances of periodic orbits observed in DC-DC converters. The effects of various converter parameters on the instability can be readily seen from the derived critical conditions. New Nyquist-like plots are also proposed to predict or prevent the occurrence of the instability.

  20. Advanced DC/DC Converters Towards Higher Volumetric Efficiencies For Space Applications

    NASA Technical Reports Server (NTRS)

    Shaw, Harry; Shue, Jack; Liu, David; Wang, Bright; Plante, Jeanette

    2005-01-01

    A new emphasis on planetary exploration by NASA drives the need for small, high power DC/DC converters which are functionally modular. NASA GSFC and other government space organizations are supporting technology development in the DC/DC converter area to both meet new needs and to promote more sources of supply. New technologies which enable miniaturization such as embedded passive technologies and thermal management using high thermal conductivity materials are features of the new designs. Construction of some simple DC/DC converter core circuits using embedded components was found to be successful for increasing volumetric efficiency to 37 W/inch. The embedded passives were also able to perform satisfactorily in this application in cryogenic temperatures.

  1. Modelling and Simulation of Digital Compensation Technique for dc-dc Converter by Pole Placement

    NASA Astrophysics Data System (ADS)

    Shenbagalakshmi, R.; Sree Renga Raja, T.

    2015-09-01

    A thorough and effective analysis of the dc-dc converters is carried out in order to achieve the system stability and to improve the dynamic performance. A small signal modelling based on state space averaging technique for dc-dc converters is carried out. A digital state feedback gain matrix is derived by pole placement technique in order to achieve the stability of a completely controllable system. A prediction observer for the dc-dc converters is designed and a dynamic compensation (observer plus control law) is provided using separation principle. The output is very much improved with zero output voltage ripples, zero peak overshoot, and much lesser settling time in the range of ms and with higher overall efficiency (>90 %).

  2. 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…

  3. High Peak Power Gyroklystron with an Inverted Magnetron Injection Gun

    NASA Astrophysics Data System (ADS)

    Read, Michael; Neilson, Jeff; Borchard, Philipp; Ives, Lawrence; Lawson, Wes

    2006-01-01

    This paper describes the design of a 25 MW, 30 GHz gyroklystron amplifier based on a coaxial RF structure. The design includes an inverted magnetron injection gun (MIG) for positioning and cooling the inner conductor. The gun produces a very low spread beam that contributes to a device efficiency of 54%. Details are given of the gun, RF structure, input and output couplers and collector.

  4. A high performance current source inverter

    SciTech Connect

    Joos, G.; Moschopoulos, G.; Ziogas, P.D.

    1993-10-01

    A recent innovation in current source inverter (CSI) drives has been the introduction of pulsewidth modulation (PWM) for the purpose of improving the quality of the load currents and voltages. However, the typical six switch CSI circuit is not compatible with all standard PWM techniques thus limiting the number of schemes that can be used. The modified CSI circuit discussed in this paper removes most of the restrictions at the ``cost`` of an extra switch. Additional advantages include faster response times through modulation index control and higher efficiency. This paper includes a detailed steady-state analysis and design procedure. The feasibility and performance of the modified CSI are verified by simulation and experimental implementation on a 5 kVA converter.

  5. An Inverter-Driven Induction Motor System with a Deadlock Breaking Capability

    NASA Astrophysics Data System (ADS)

    Ichikawa, Takuto; Yoshida, Toshiya; Miyashita, Osamu

    Induction motors are very widely used in various industrial applications. In semiconductor manufacturing processes, deadlock failure of pumps may occur by the adhering of glass material contained in the gas to the rotor. This can lead to the shutdown of the manufacturing plant. Therefore, a countermeasure to prevent deadlocking of a motor is required. This paper proposes a method for generating an impulse torque in an induction motor fed by an inverter. The proposed inverter circuit is composed of a conventional inverter and a few additional relays. The on-and-off control of the relays supplies an appropriate magnetizing current and a large torque current from the dc-link capacitor. In experiment, a 1.5-kW cage-type induction motor generated a torque that was approximately seven times larger than the rated torque of the motor. This large impulse torque is useful for breaking the motor deadlock.

  6. 20 kHz main inverter unit. [for space station power supplies

    NASA Technical Reports Server (NTRS)

    Hussey, S.

    1989-01-01

    A proof-of-concept main inverter unit has demonstrated the operation of a pulse-width-modulated parallel resonant power stage topology as a 20-kHz ac power source driver, showing simple output regulation, parallel operation, power sharing and short-circuit operation. The use of a two-stage dc input filter controls the electromagnetic compatibility (EMC) characteristics of the dc power bus, and the use of an ac harmonic trap controls the EMC characteristics of the 20-kHz ac power bus.

  7. Familial inverted duplication 7p

    SciTech Connect

    Schaefer, G.B.; Novak, K.; Steele, D.

    1995-03-27

    A 10-month-old female with developmental delay and failure to thrive was referred for genetic evaluation as part of an adoption assessment. Physical exam showed a mildly beaked nose and clinodactyly, but otherwise nothing remarkable. Chromosome analysis showed an inverted duplication of the p12.2{r_arrow}p13 portion of chromosome 7(46,XX,dup(7)(p13p12.2)). The proposita`s older brother, mother, and grandmother were cognitively delayed and had the same chromosome 7 duplication. A review of the literature showed no other cases involving this exact duplication. 5 refs., 3 figs., 1 tab.

  8. System and method for regulating resonant inverters

    DOEpatents

    Stevanovic, Ljubisa Dragoljub; Zane, Regan Andrew

    2007-08-28

    A technique is provided for direct digital phase control of resonant inverters based on sensing of one or more parameters of the resonant inverter. The resonant inverter control system includes a switching circuit for applying power signals to the resonant inverter and a sensor for sensing one or more parameters of the resonant inverter. The one or more parameters are representative of a phase angle. The resonant inverter control system also includes a comparator for comparing the one or more parameters to a reference value and a digital controller for determining timing of the one or more parameters and for regulating operation of the switching circuit based upon the timing of the one or more parameters.

  9. Multilevel Inverters for Electric Vehicle Applications

    SciTech Connect

    Habetler, T.G.; Peng, F.Z.; Tolbert, L.M.

    1998-10-22

    This paper presents multilevel inverters as an application for all-electric vehicle (EV) and hybrid-electric vehicle (HEV) motor drives. Diode-clamped inverters and cascaded H-bridge inverters, (1) can generate near-sinusoidal voltages with only fundamental frequency switching; (2) have almost no electromagnetic interference (EMI) and common-mode voltage; and (3) make an EV more accessible/safer and open wiring possible for most of an EV'S power system. This paper explores the benefits and discusses control schemes of the cascade inverter for use as an EV motor drive or a parallel HEV drive and the diode-clamped inverter as a series HEV motor drive. Analytical, simulated, and experimental results show the superiority of these multilevel inverters for this new niche.

  10. Silicon-controlled-rectifier square-wave inverter with protection against commutation failure

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.

    1971-01-01

    The square-wave SCR inverter that was designed, built, and tested includes a circuit to turn off the inverter in case of commutation failure. The basic power stage is a complementary impulse-commutated parallel inverter consisting of only six components. The 400-watt breadboard was tested while operating at + or - 28 volts, and it had a peak efficiency of 95.5 percent at 60 hertz and 91.7 percent at 400 hertz. The voltage regulation for a fixed input was 3 percent at 60 hertz. An analysis of the operation and design information is included.

  11. Single phase inverter for a three phase power generation and distribution system

    NASA Technical Reports Server (NTRS)

    Lindena, S. J.

    1976-01-01

    A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7.

  12. Status and Needs of Power Electronics for Photovoltaic Inverters: Summary Document

    SciTech Connect

    WEST, RICK; MAUCH, KONRAD; QIN,YU CHIN; MOHAN,NED; BONN, RUSSELL H.

    2002-04-01

    Photovoltaic inverters are the most mature of any DER inverter, and their mean time to first failure (MTFF) is about five years. This is an unacceptable MTFF and will inhibit the rapid expansion of PV. With all DER technologies, (solar, wind, fuel cells, and microturbines) the inverter is still an immature product that will result in reliability problems in fielded systems. The increasing need for all of these technologies to have a reliable inverter provides a unique opportunity to address these needs with focused R&D development projects. The requirements for these inverters are so similar that modular designs with universal features are obviously the best solution for a ''next generation'' inverter. A ''next generation'' inverter will have improved performance, higher reliability, and improved profitability. Sandia National Laboratories has estimated that the development of a ''next generation'' inverter could require approximately 20 man-years of work over an 18- to 24-month time frame, and that a government-industry partnership will greatly improve the chances of success.

  13. Advanced Photovoltaic Inverter Functionality using 500 kW Power Hardware-in-Loop Complete System Laboratory Testing: Preprint

    SciTech Connect

    Mather, B. A.; Kromer, M. A.; Casey, L.

    2013-01-01

    With the increasing penetration of distribution connected photovoltaic (PV) systems, more and more PV developers and utilities are interested in easing future PV interconnection concerns by mitigating some of the impacts of PV integration using advanced PV inverter controls and functions. This paper describes the testing of a 500 kW PV inverter using Power Hardware-in-Loop (PHIL) testing techniques. The test setup is described and the results from testing the inverter in advanced functionality modes, not commonly used in currently interconnected PV systems, are presented. PV inverter operation under PHIL evaluation that emulated both the DC PV array connection and the AC distribution level grid connection are shown for constant power factor (PF) and constant reactive power (VAr) control modes. The evaluation of these modes was completed under varying degrees of modeled PV variability.

  14. Design of power electronics for TVC EMA systems

    NASA Astrophysics Data System (ADS)

    Nelms, R. Mark

    1993-08-01

    The Composite Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. This report presents the results of an investigation into the applicability of two new technologies, MOS-controlled thyristors (MCT's) and pulse density modulation (PDM), to the control of brushless dc motors in EMA systems. MCT's are new power semiconductor devices, which combine the high voltage and current capabilities of conventional thyristors and the low gate drive requirements of metal oxide semiconductor field effect transistors (MOSFET's). The commanded signals in a PDM system are synthesized using a series of sinusoidal pulses instead of a series of square pulses as in a pulse width modulation (PWM) system. A resonant dc link inverter is employed to generate the sinusoidal pulses in the PDM system. This inverter permits zero-voltage switching of all semiconductors which reduces switching losses and switching stresses. The objectives of this project are to develop and validate an analytical model of the MCT device when used in high power motor control applications and to design, fabricate, and test a prototype electronic circuit employing both MCT and PDM technology for controlling a brushless dc motor.

  15. Design of power electronics for TVC EMA systems

    NASA Technical Reports Server (NTRS)

    Nelms, R. Mark

    1993-01-01

    The Composite Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently developing a class of electromechanical actuators (EMA's) for use in space transportation applications such as thrust vector control (TVC) and propellant control valves (PCV). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 volts. MSFC has selected the brushless dc motor for implementation in EMA's. This report presents the results of an investigation into the applicability of two new technologies, MOS-controlled thyristors (MCT's) and pulse density modulation (PDM), to the control of brushless dc motors in EMA systems. MCT's are new power semiconductor devices, which combine the high voltage and current capabilities of conventional thyristors and the low gate drive requirements of metal oxide semiconductor field effect transistors (MOSFET's). The commanded signals in a PDM system are synthesized using a series of sinusoidal pulses instead of a series of square pulses as in a pulse width modulation (PWM) system. A resonant dc link inverter is employed to generate the sinusoidal pulses in the PDM system. This inverter permits zero-voltage switching of all semiconductors which reduces switching losses and switching stresses. The objectives of this project are to develop and validate an analytical model of the MCT device when used in high power motor control applications and to design, fabricate, and test a prototype electronic circuit employing both MCT and PDM technology for controlling a brushless dc motor.

  16. Compact Low Cost Hybrid DC/DC Converter Controller For Space Applications

    NASA Astrophysics Data System (ADS)

    Volpi, Gian Franco; Contissa, Alessandro; Mantegazza, Massimiliano

    2011-10-01

    The need for low cost, space qualified (ESA requirements), compact DC/DC converters is becoming increasingly important both for commercial market and programs controlled by space administration. Market is also showing request for large scale production. To face market needs, the design of low power multi- output DC/DC converters can be based on small and low mass hybrid controllers for better mechanical optimization. Moreover, this approach, maintaining robust performances against harsh space environment, allows taking the advantages typical of recurrent design: high reliability and reduction of cost. Also, using the hybrid controller allows designers to focus just on power transformer and filters, reducing the time necessary to complete the design. This paper shall provide description of the standard Thales Alenia Space hybrid controller in its two variants: 40V-760V (HYLPSC03RAD) and 20.5V-43V (HYLPSC04RAD) bus voltage.

  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. Forback DC-to-DC converter

    NASA Technical Reports Server (NTRS)

    Lukemire, Alan T. (Inventor)

    1993-01-01

    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.

  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. Phase synchronized quasiperiodicity in power electronic inverter systems

    NASA Astrophysics Data System (ADS)

    Zhusubaliyev, Zhanybai T.; Mosekilde, Erik; Andriyanov, Alexey I.; Shein, Vladimir V.

    2014-02-01

    The development of switch-mode operated power electronic converter systems has provided a broad range of new effective approaches to the conversion of electric power. In this paper we describe the transitions from regular periodic operation to quasiperiodicity and high-periodic resonance behavior that can be observed in a pulse-width modulated DC/AC converter operating with high feedback gain. We demonstrate the occurrence of two different types of torus birth bifurcations and present a series of phase portraits illustrating the appearance of phase-synchronized quasiperiodicity. Our numerical findings are verified through comparison with an experimental inverter system. The results shed light on the transitions to quasiperiodicity and to various forms of three-frequency dynamics in non-smooth systems.

  1. EV drivetrain inverter with V/HZ optimization

    DOEpatents

    Gritter, David J.; O'Neil, Walter K.

    1986-01-01

    An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer which calculates optimized machine control data signals from various parametric inputs and during steady state load conditions, seeks a best V/HZ ratio to minimize battery current drawn (system losses) from a D.C. power source (32). In the preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack and a three-phase induction motor (18).

  2. Inverted File Compression through Document Identifier Reassignment.

    ERIC Educational Resources Information Center

    Shieh, Wann-Yun; Chen, Tien-Fu; Shann, Jean Jyh-Jiun; Chung, Chung-Ping

    2003-01-01

    Discusses the use of inverted files in information retrieval systems and proposes a document identifier reassignment method to reduce the average gap values in an inverted file. Highlights include the d-gap technique; document similarity; heuristic algorithms; file compression; and performance evaluation from a simulation environment. (LRW)

  3. Inverted follicular keratosis successfully treated with imiquimod.

    PubMed

    Karadag, Ayse Serap; Ozlu, Emin; Uzuncakmak, Tugba Kevser; Akdeniz, Necmettin; Cobanoglu, Bengu; Oman, Berkant

    2016-01-01

    Inverted follicular keratosis is a rare benign tumor of the follicular infundibulum characterized by exo-endophytic growing. It is thought to be a rare variant of the seborrheic keratosis. The diagnosis of inverted follicular keratosis is generally established histopathologically because clinical differentiation from other lesions is difficult. Herein, we present one such rare case, successfully treated with topical 5% imiquimod cream. PMID:27294052

  4. Inverted follicular keratosis successfully treated with imiquimod

    PubMed Central

    Karadag, Ayse Serap; Ozlu, Emin; Uzuncakmak, Tugba Kevser; Akdeniz, Necmettin; Cobanoglu, Bengu; Oman, Berkant

    2016-01-01

    Inverted follicular keratosis is a rare benign tumor of the follicular infundibulum characterized by exo-endophytic growing. It is thought to be a rare variant of the seborrheic keratosis. The diagnosis of inverted follicular keratosis is generally established histopathologically because clinical differentiation from other lesions is difficult. Herein, we present one such rare case, successfully treated with topical 5% imiquimod cream. PMID:27294052

  5. Circuit controls transients in SCR inverters

    NASA Technical Reports Server (NTRS)

    Moore, E. T.; Wilson, T. G.

    1964-01-01

    Elimination of starting difficulties in SCR inverters is accomplished by the addition of two taps of the output winding of the inverter. On starting or under transient loads, the two additional taps deliver power through diodes without requiring quenching of SCR currents in excess of normal starting load.

  6. A SiC MOSFET Based Inverter for Wireless Power Transfer Applications

    SciTech Connect

    Onar, Omer C; Chinthavali, Madhu Sudhan; Campbell, Steven L; Ning, Puqi; White, Cliff P; Miller , John M.

    2014-01-01

    In a wireless power transfer (WPT) system, efficiency of the power conversion stages is crucial so that the WPT technology can compete with the conventional conductive charging systems. Since there are 5 or 6 power conversion stages, each stage needs to be as efficient as possible. SiC inverters are crucial in this case; they can handle high frequency operation and they can operate at relatively higher temperatures resulting in reduces cost and size for the cooling components. This study presents the detailed power module design, development, and fabrication of a SiC inverter. The proposed inverter has been tested at three center frequencies that are considered for the WPT standardization. Performance of the inverter at the same target power transfer level is analyzed along with the other system components. In addition, another SiC inverter has been built in authors laboratory by using the ORNL designed and developed SiC modules. It is shown that the inverter with ORNL packaged SiC modules performs simular to that of the inverter having commercially available SiC modules.

  7. Nanostructured Inverted Organic Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Thomas, Michael

    Organic photovoltaic cells (OPVs)are promising devices for inexpensive power generation from sunlight. Organic semiconductors, the basic materials for OPVs, can be fabricated using a broad range of fabrication technologies from vapor deposition to solution processing. Upon light absorption, a strongly bound exciton is generated which can diffuse to a donor-acceptor heterojunction. At this interface it can be dissociated into free charge carriers which can be collected by the device electrodes. A major challenge for OPVs are short exciton diffusion lengths of up to 20 nm. Morphology engineering is required in order to harvest the exciton before it recombines and improve OPV performance. This work focuses on the study of nanostructured morphologies for use in inverted architecture OPVs. Glancing angle deposition (GLAD)is employed to fabricate nanocolumnar acceptor films. Through combining these nanostructured C60 films with a conjugated polymer donor P3CBT and a small molecule 3-Q, inverted OPVs are fabricated with the goal to analyze effect of morphology engineering on device performance. A major challenge was that C60 were found to be soluble in most commonly used organic solvents such as dichlorobenzene or chloroform. Although this challenge has limited the donor choice and therefore has limited device performance, a significant effect of morphology engineering could be observed. All GLAD structured C60 OPVs outperformed state of the art architectures such as planar films and bulk heterojunctions fabricated with the same materials. For P3CBT in particular the GLAD structured devices exhibited a twofold increase in power conversion efficiency compared with bulk heterojunctions and a fourfold increase compared with planar devices. In a further study, the acceptor materials PTCDA and C60 were co-evaporated into a single film. PTCDA is stable against non-polar organic solvents while C60 provides a high electron mobility. Nanocolumnar acceptor blended PTCDA:C60 films

  8. Power Quality Control and Design of Power Converter for Variable-Speed Wind Energy Conversion System with Permanent-Magnet Synchronous Generator

    PubMed Central

    Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

    2013-01-01

    The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

  9. Power quality control and design of power converter for variable-speed wind energy conversion system with permanent-magnet synchronous generator.

    PubMed

    Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

    2013-01-01

    The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

  10. 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.

  11. High fill factor and thermal stability of bilayer organic photovoltaic cells with an inverted structure

    NASA Astrophysics Data System (ADS)

    Wang, Zhongqiang; Hong, Ziruo; Zhuang, Taojun; Chen, Guo; Sasabe, Hisahiro; Yokoyama, Daisuke; Kido, Junji

    2015-02-01

    In this study, we fabricated planar heterojunction photovoltaic cells with inverted device structures based on tetraphenyldibenzoperiflanthene and fullerene-70 (C70). With proper designs of device architecture and selection of electrode buffers, a high fill factor and power conversion efficiency were obtained due to large shunt resistance (Rsh) and efficient carrier collection. Optical simulation reveals that field-dependent recombination is depressed in the inverted structure cells because of less light absorption in short wavelength range, resulting in high fill factor. More importantly, high thermal stability of inverted structure cells was demonstrated via utilizing stable electrode buffers.

  12. Four new cases of inverted terminal duplication: A modified hypothesis of mechanism of origin

    SciTech Connect

    Hoo, J.J.; Chao, M.; Szego, K.

    1995-09-25

    We present 4 recently diagnosed cases of inverted tandem duplication with involvement of the respective terminal band. Based on these 4 cases and review of the literature, the term {open_quotes}inverted terminal duplication{close_quotes} is proposed to designate specifically the type of inverted tandem duplication which involves the terminal band. A modification of the previous hypothesis of mechanism of origin is advanced. It is speculated further that a telomeric deletion of a meiotic chromosome followed by a U-type reunion of the chromatids, considered to be the first steps of the proposed mechanism of origin, may not be a rare gonadal event. 12 refs., 5 figs.

  13. 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.

  14. High-Voltage 1-kW dc/dc Converter Developed for Low-Temperature Operation

    NASA Technical Reports Server (NTRS)

    Patterson, Richard L.

    1998-01-01

    Recently, Lewis developed and demonstrated a high-voltage, 1-kW dc/dc converter that operates from room temperature to -184 C. A power supply designed for use in a NASA ion beam propulsion system was utilized as a starting point for the design of a low- (wide-) temperature dc/dc converter. For safety, we decided to halve the output voltage and power level, so the converter was designed for an 80-Vdc input and a 550-Vdc output at 1 kW.

  15. Spin–orbit coupling induced magnetoresistance oscillation in a dc biased two-dimensional electron system.

    PubMed

    Wang, C M; Lei, X L

    2014-06-11

    We study dc-current effects on the magnetoresistance oscillation in a two-dimensional electron gas with Rashba spin-orbit coupling, using the balance-equation approach to nonlinear magnetotransport. In the weak current limit the magnetoresistance exhibits periodical Shubnikov-de Haas oscillation with changing Rashba coupling strength for a fixed magnetic field. At finite dc bias, the period of the oscillation halves when the interbranch contribution to resistivity dominates. With further increasing current density, the oscillatory resistivity exhibits phase inversion, i.e., magnetoresistivity minima (maxima) invert to maxima (minima) at certain values of the dc bias, which is due to the current-induced magnetoresistance oscillation. PMID:25932474

  16. Compact dc link

    SciTech Connect

    Flairty, C. )

    1991-10-01

    The EPRI Compact Substation Project (a HVDC Converter Station) was developed, designed, and constructed per EPRI Agreement RP213. In December 1983, the converter station operated at its rating (100 MW power transmission and 300 kV dc bias plus 100 kV operating voltage). From January to May 1984, the converter station operated at various power transmission levels. Operation was intermittent due to a randomly occurring voltage breakdown. The voltage breakdown was isolated to the steel tanks containing the thyristor valves in an SF{sub 6} environment. The type of insulators stressed within the valve tanks were: (1) the epoxy cone shape insulators providing an interface to the bus entering the valve tank; (2) epoxy fiberglass hydraulic columns for the flow of the R113 refrigerant to and from the thyristor valves; and (3) the epoxy fiberglass support columns supporting the thyristor valves from the floor of the valve tank. The cause of the randomly occurring breakdown was investigated and determined to be the epoxy fiberglass support columns. The random dielectric breakdowns were due to excessive voltage gradients existing at the epoxy fiberglass support columns. This probably was caused by the misplacement of an internal insert within the column with respect to an external shield on the column. The cost and time to retrofit the support columns outweighed the benefits expected from resuming the project. Consequently, work was terminated and the equipment disassembled. Examination of the epoxy fiberglass support columns revealed several arcing tracks along the inside surface confirming the earlier hypothesis. 53 figs., 32 tabs.

  17. 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.

  18. Switching Characteristics of Ferroelectric Transistor Inverters

    NASA Technical Reports Server (NTRS)

    Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

    2010-01-01

    This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

  19. Static Characteristics of the Ferroelectric Transistor Inverter

    NASA Technical Reports Server (NTRS)

    Mitchell, Cody; Laws, crystal; MacLeond, Todd C.; Ho, Fat D.

    2010-01-01

    The inverter is one of the most fundamental building blocks of digital logic, and it can be used as the foundation for understanding more complex logic gates and circuits. This paper presents the characteristics of an inverter circuit using a ferroelectric field-effect transistor. The voltage transfer characteristics are analyzed with respect to varying parameters such as supply voltage, input voltage, and load resistance. The effects of the ferroelectric layer between the gate and semiconductor are examined, and comparisons are made between the inverters using ferroelectric transistors and those using traditional MOSFETs.

  20. Inverted spectra of SWCNT films

    NASA Astrophysics Data System (ADS)

    Lehman, John; Hurst, Katherine; Roberson, Lara; Nield, Kathryn; Hamlin, John

    2008-03-01

    Diffuse Reflectance for purified single wall carbon nanotube (SWCNT) films and its relation to absorptance in the wavelength range 0.6 μm to 2 μm are inverted when compared to absorptivity data in the literature. This surprising behavior has been corroborated by diffuse reflectance measurements and shows that the reflectance is a substantial part of the unique optical behavior. Typically, the absorptance is fairly assumed to be complementary to the transmittance, while the reflectivity is insignificant. Only in certain instances (see for example, Barnes, et. al[1], Wang, et. al[2]), is the small reflectance explicitly accounted for. In the present work, we present diffuse reflectance and specular absorptance at normal incidence of SWCNT films. [1] T. M. Barnes, J. van de Lagemaat, D. Levi,1 G. Rumbles, T. J. Coutts, C. L. Weeks, D. A. Britz, I. Levitsky, J. Peltola, P. Glatkowski, Phys. Rev. B 75, 235410 (2007). [2] F. Wang, M. Y. Sfeir, L. Huang, X. M. H. Huang, Wu, J. Kim, J. Hone, S. O'Brien, L. E. Brus, T. F. Heinz, PRL 96, 167401 (2006).

  1. A Five-Level Cascade Multilever Invertor Three-Phase Motor Drive Using a Single DC Source

    SciTech Connect

    Chiasson, J.N.

    2006-09-15

    A method is presented showing that a 5-level cascade multilevel inverter for a three-phase permanent magnet synchronous motor drive can be implemented using only a single DC link to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. It is shown that the capacitor voltages can be regulated while achieving an output voltage waveform that is 20% greater than that obtained using the standard 3-leg inverter alone. Finally conditions are given in terms of the power factor and modulation index that determine when the capacitor voltage can regulated.

  2. Sizing SiC Storage Inverters for Fast Grid Frequency Support

    SciTech Connect

    Hoke, Anderson; Bennion, Kevin; Gevorgian, Vahan; Chakraborty, Sudipta; Muljadi, Eduard

    2015-11-02

    As wind and solar displace synchronous generators whose inertia stabilizes the AC grid frequency on fast time scales, it has been proposed to use energy storage systems (ESSs) to mitigate frequency transient events. Such events require a rapid surge of power from the ESS, but they occur only rarely. The high temperature tolerance of SiC MOSFETs and diodes presents an opportunity for innovative ESS inverter designs. Herein we investigate a SiC ESS inverter design such that the SiC device ratings are obeyed during mild frequency events but are exceeded during rare, major events, for a potentially more economical inverter design. In support of this proposal we present: 1. An analysis of four years of grid frequency events in the U.S. Western Interconnection. 2. A switch-level ESS inverter simulation using SiC devices with detailed loss estimates. 3. Thermal analysis of the SiC power modules during a worst-case frequency event, showing that the modules can likely withstand the brief overcurrent. This analysis supports the conclusion that it may be advantageous for economical designs (acknowledging the increased risks) to undersize the SiC switches when designing inverters to perform active power control for grid frequency support. Such a strategy may result in SiC-based designs being more competitive with less costly silicon IGBT-based designs.

  3. 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.

  4. 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.

  5. DC attenuation meter

    DOEpatents

    Hargrove, Douglas L.

    2004-09-14

    A portable, hand-held meter used to measure direct current (DC) attenuation in low impedance electrical signal cables and signal attenuators. A DC voltage is applied to the signal input of the cable and feedback to the control circuit through the signal cable and attenuators. The control circuit adjusts the applied voltage to the cable until the feedback voltage equals the reference voltage. The "units" of applied voltage required at the cable input is the system attenuation value of the cable and attenuators, which makes this meter unique. The meter may be used to calibrate data signal cables, attenuators, and cable-attenuator assemblies.

  6. Adaptive output voltage tracking controller for uncertain DC/DC boost converter

    NASA Astrophysics Data System (ADS)

    Lee, Byoung-Seoup; Kim, Seok-Kyoon; Park, Jin-Hyuk; Lee, Kyo-Beum

    2016-06-01

    This paper presents a cascade output voltage control strategy for an uncertain DC/DC boost converter adopting an adaptive current controller in its inner loop. Considering the non-linearity, load uncertainties and parameter uncertainties of the converter, the proposed controller is designed following the conventional cascade voltage controller design method. The proposed method makes the following three contributions. First, a coordinate transformation is introduced for the inner loop, enabling avoidance of the singularity problem caused by the estimates of uncertain parameters. Second, a slight modification to the adaptation law is performed to guarantee closed-loop stability in the presence of the time-varying component of the load current. Third, the outer-loop controller is devised such that its performance can be adjusted without any parameter information. The closed-loop performance is demonstrated through simulations and experiments using the DSP28335 with a 3 kW DC/DC boost converter.

  7. Advanced Power Electronic Interfaces for Distributed Energy Systems, Part 2: Modeling, Development, and Experimental Evaluation of Advanced Control Functions for Single-Phase Utility-Connected Inverter

    SciTech Connect

    Chakraborty, S.; Kroposki, B.; Kramer, W.

    2008-11-01

    Integrating renewable energy and distributed generations into the Smart Grid architecture requires power electronic (PE) for energy conversion. The key to reaching successful Smart Grid implementation is to develop interoperable, intelligent, and advanced PE technology that improves and accelerates the use of distributed energy resource systems. This report describes the simulation, design, and testing of a single-phase DC-to-AC inverter developed to operate in both islanded and utility-connected mode. It provides results on both the simulations and the experiments conducted, demonstrating the ability of the inverter to provide advanced control functions such as power flow and VAR/voltage regulation. This report also analyzes two different techniques used for digital signal processor (DSP) code generation. Initially, the DSP code was written in C programming language using Texas Instrument's Code Composer Studio. In a later stage of the research, the Simulink DSP toolbox was used to self-generate code for the DSP. The successful tests using Simulink self-generated DSP codes show promise for fast prototyping of PE controls.

  8. Designing Magnetic Components for High Frequency DC-DC Converters

    NASA Technical Reports Server (NTRS)

    McLyman, W. T.

    1993-01-01

    The conversion process in power electronics requires the use of tranformers and inductors, components which frequenly are the heaviest and bulkiest item in the conversion circuits. They also have a significant effect upon the overall performance and efficiency of the system.

  9. Removing Barriers to Utility Interconnected Photovoltaic Inverters

    SciTech Connect

    Gonzalez, S.; Bonn, R.H.; Ginn, J.W.

    2000-10-03

    The Million Solar Roofs Initiative has motivated a renewed interest in the development of utility interconnected photovoltaic (UIPV) inverters. Government-sponsored programs (PVMaT, PVBONUS) and competition among utility interconnected inverter manufacturers have stimulated innovations and improved the performance of existing technologies. With this resurgence, Sandia National Laboratories (SNL) has developed a program to assist industry initiatives to overcome barriers to UIPV inverters. In accordance with newly adopted IEEE 929-2000, the utility interconnected PV inverters are required to cease energizing the utility grid when either a significant disturbance occurs or the utility experiences an interruption in service. Compliance with IEEE 929-2000 is being widely adopted by utilities as a minimum requirement for utility interconnection. This report summarizes work done at the SNL balance-of-systems laboratory to support the development of IEEE 929-2000 and to assist manufacturers in meeting its requirements.

  10. Base drive for paralleled inverter systems

    NASA Technical Reports Server (NTRS)

    Nagano, S. (Inventor)

    1980-01-01

    In a paralleled inverter system, a positive feedback current derived from the total current from all of the modules of the inverter system is applied to the base drive of each of the power transistors of all modules, thereby to provide all modules protection against open or short circuit faults occurring in any of the modules, and force equal current sharing among the modules during turn on of the power transistors.

  11. Automatic load sharing in inverter modules

    NASA Technical Reports Server (NTRS)

    Nagano, S.

    1979-01-01

    Active feedback loads transistor equally with little power loss. Circuit is suitable for balancing modular inverters in spacecraft, computer power supplies, solar-electric power generators, and electric vehicles. Current-balancing circuit senses differences between collector current for power transistor and average value of load currents for all power transistors. Principle is effective not only in fixed duty-cycle inverters but also in converters operating at variable duty cycles.

  12. Inverted liver with suprahepatic, anteriorly displaced gallbladder.

    PubMed

    Hibbs, Harold; Ahmad, Usman

    2010-01-01

    A suprahepatic, anteriorly displaced gallbladder in association with an inverted liver is an extremely rare congenital anomaly. We report the clinical and radiologic findings associated with a 78-year-old woman presenting with shortness of breath, desaturation, hypercapnia and hypoxemia. An abnormal chest radiograph demonstrated right hemi-diaphragmatic elevation consistent with a possible eventration. Subsequent imaging by computed tomography (CT) demonstrated an inverted liver with an anteriorly displaced, suprahepatic gallbladder. PMID:20666167

  13. Work Station For Inverting Solar Cells

    NASA Technical Reports Server (NTRS)

    Feder, H.; Frasch, W.

    1982-01-01

    Final work station along walking-beam conveyor of solar-array assembly line turns each pretabbed solar cell over, depositing it back-side-up onto landing pad, which centers cell without engaging collector surface. Solar cell arrives at inverting work station collector-side-up with two interconnect tabs attached to collector side. Cells are inverted so that second soldering operation takes place in plain view of operator. Inversion protects collector from damage when handled at later stages of assembly.

  14. High performance dc-dc conversion with voltage multipliers. [using transformerless capacitor diode circuit

    NASA Technical Reports Server (NTRS)

    Harrigill, W. T., Jr.; Myers, I. T.

    1974-01-01

    An experimental 100W 1000V dc-dc converter using a capacitor diode voltage multipler (CDVM) with a nominal frequency of 100 kHz is studied. A component weight of about 1 kg/kW was obtained. Design equations for current, output -ripple and -power, efficiency and output voltage are derived. Agreement between experimental results and calculations is fairly good except for ripple.

  15. Comparison of solar panel cooling system by using dc brushless fan and dc water

    NASA Astrophysics Data System (ADS)

    Irwan, Y. M.; Leow, W. Z.; Irwanto, M.; M, Fareq; Hassan, S. I. S.; Safwati, I.; Amelia, A. R.

    2015-06-01

    The purpose of this article is to discuss comparison of solar panel cooling system by using DC brushless fan and DC water pump. Solar photovoltaic (PV) power generation is an interesting technique to reduce non-renewable energy consumption and as a renewable energy. The temperature of PV modules increases when it absorbs solar radiation, causing a decrease in efficiency. A solar cooling system is design, construct and experimentally researched within this work. To make an effort to cool the PV module, Direct Current (DC) brushless fan and DC water pump with inlet/outlet manifold are designed for constant air movement and water flow circulation at the back side and front side of PV module representatively. Temperature sensors were installed on the PV module to detect temperature of PV. PIC microcontroller was used to control the DC brushless fan and water pump for switch ON or OFF depend on the temperature of PV module automatically. The performance with and without cooling system are shown in this experiment. The PV module with DC water pump cooling system increase 3.52%, 36.27%, 38.98%in term of output voltage, output current, output power respectively. It decrease 6.36 °C compare than to PV module without DC water pump cooling system. While DC brushless fan cooling system increase 3.47%, 29.55%, 32.23%in term of output voltage, output current, and output power respectively. It decrease 6.1 °C compare than to PV module without DC brushless fan cooling system. The efficiency of PV module with cooling system was increasing compared to PV module without cooling system; this is because the ambient temperature dropped significantly. The higher efficiency of PV cell, the payback period of the system can be shorted and the lifespan of PV module can also be longer.

  16. Are Archean lithospheric keels inverted?

    NASA Astrophysics Data System (ADS)

    Percival, J. A.; Pysklywec, R. N.

    2007-02-01

    Post-tectonic granite "blooms" in many Archean cratons manifest widespread crustal melting that cannot be explained by lithosphere removal, considering the long-term buoyancy of Archean cratonic keels and low mantle geotherms indicated by Archean diamondiferous lithosphere. Rather, heat may have been transferred from the mantle through a process of lithosphere inversion, driven by basal tractive forces acting on gravitationally unstable lithosphere. The top-heavy cell comprises eclogitic lower crust ( ρ = 3500 kg/m 3) lying above depleted mantle lithosphere ( ρ = 3300 kg/m 3), whose aggregate density remained less than that of surrounding asthenosphere ( ρ = 3340 kg/m 3). Parameterized numerical models of the inversion process show a > 40 m.y. pulse of maximum 1060 °C temperatures in the lower crust, sufficient to drive anhydrous melting, when overturned basal lithosphere reaches the Moho. In equilibrating to lower lithosphere conditions, the eclogitic cap may have yielded siliceous melts that infiltrated overlying, previously depleted mantle, producing the high Si/Mg characteristic of some cratonic peridotites. P-T paths calculated for the central part of the inverting cell criss-cross the graphite-diamond boundary, explaining development of large diamond crystals through numerous growth increments. The craton stabilization process follows terminal tectonism by about 50 m.y. as a result of initial cooling, eclogite formation and lithosphere stiffening. Related consequences in the crust include low-pressure regional metamorphism and widespread hydrothermal effects including some gold mineralization. Craton stability is attributed to the high strength of the depleted mantle lithosphere, its rectified density profile, and the presence of refractory compositions at the lithosphere-asthenosphere boundary.

  17. 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.

  18. DYLOS DC110

    EPA Science Inventory

    The Dylos DC1100 air quality monitor measures particulate matter (PM) to provide a continuous assessment of indoor air quality. The unit counts particles in two size ranges: large and small. According to the manufacturer, large particles have diameters between 2.5 and 10 micromet...

  19. PM brushless DC motor drive with a new power converter topology

    SciTech Connect

    Krishnan, R.; Lee, S.

    1995-12-31

    With the growing potential for widespread use of permanent magnet brushless dc motor drives (hereafter referred to as PMBDC drives) in many low-cost applications such as in hvac, refrigerators, and freezers in houses and small velocity servos in process industries, it has become important to minimize the cost. One obvious place for cost reduction is in the cost of the inverter and its associated controller. With that perspective, a novel application of the converter topology for the PMBDC known as C-dump in the switched reluctance motor drives is proposed in this paper. The advantages and disadvantages of this topology vis-a-vis the conventional 3 phase H-bridge converter, are highlighted from the points of view of economy in switches, volt ampere rating, associated controller cost, and packaging. Design considerations for the PMBDC motor are derived for use with the proposed converter topology. The operational and design characteristics of this converter driven PMBDC drive are derived for four quadrant performance. Guidelines for the design of the proposed performance. Guidelines for the design of the proposed topology are derived and presented in the paper. Experimental results from a laboratory prototype are presented to validate the feasibility of the proposed PMBDC drive system.

  20. Robust sliding mode control applied to double Inverted pendulum system

    SciTech Connect

    Mahjoub, Sonia; Derbel, Nabil; Mnif, Faical

    2009-03-05

    A three hierarchical sliding mode control is presented for a class of an underactuated system which can overcome the mismatched perturbations. The considered underactuated system is a double inverted pendulum (DIP), can be modeled by three subsystems. Such structure allows the construction of several designs of hierarchies for the controller. For all hierarchical designs, the asymptotic stability of every layer sliding mode surface and the sliding mode surface of subsystems are proved theoretically by Barbalat's lemma. Simulation results show the validity of these methods.

  1. Multi-purpose grid-tied inverter with smart grid capabilities

    NASA Astrophysics Data System (ADS)

    Liyanagedera, Chamika Mihiranga

    Distributed energy storages play an important role in increasing the reliability and efficiency of the grid through means of peak load shaving, grid voltage support, and grid frequency support. It is important to have distributed energy storages that can utilize the functionalities of the modern smart grid to operate more effectively. The grid-tied inverter is one of the major components in a distributed energy storage that controls the power transfer between the grid and an energy storage device. In this research, a grid-tied inverter that can be used in distributed energy storage applications was designed, developed, and tested. This grid-tied inverter was designed with the capability to control both reactive and active power flow in either direction. The grid-tied inverter is equipped with communication capabilities so it can be remotely controlled by commands sent through a smart grid network. For demonstrative purposes, a user interface was developed to control and monitor the operation of the grid-tied inverter. Finally the operation of the grid-tied inverter was evaluated in accordance to IEEE 1547, the Standard for Interconnecting Distributed Resources with Electric Power Systems.

  2. Regulated dc-to-dc converter features low power drain

    NASA Technical Reports Server (NTRS)

    Thornwall, J.

    1968-01-01

    A regulated dc-to-dc converter requires negligible standby power for the operation of critical electronic equipment. The main operating circuitry consumes power intermittently according to load conditions, rather than constantly.

  3. Inverter Load Rejection Over-Voltage Testing: SolarCity CRADA Task 1a Final Report

    SciTech Connect

    Nelson, A.; Hoke, A.; Chakraborty, S.; Chebahtah, J.; Wang, T.; Zimmerly, B.

    2015-02-01

    Various interconnection challenges exist when connecting distributed PV into the electrical distribution grid in terms of safety, reliability, and stability of electric power systems. One of the urgent areas for additional research - as identified by inverter manufacturers, installers, and utilities - is the potential for transient over-voltage from PV inverters. In one stage of a cooperative tests were repeated a total of seven times. The maximum over-voltage measured in any test did not exceed 200% of nominal, and typical over-voltage levels were significantly lower. The total voltage duration and the maximum continuous time above each threshold are presented here, as well as the time to disconnect for each test. Finally, we present a brief investigation into the effect of DC input voltage as well as a series of no-load tests. This report describes testing conducted at NREL to determine the duration and magnitude of transient over-voltages created by several commercial PV inverters during load-rejection conditions. For this work, a test plan that is currently under development by the Forum on Inverter Grid Integration Issues (FIGII) has been implemented in a custom test setup at NREL. Through a cooperative research and development agreement, NREL is working with SolarCity to address two specific types of transient overvoltage: load rejection overvoltage (LRO) and ground fault overvoltage (GFO). Additional partners in this effort include the Hawaiian Electric Companies, Northern Plains Power Technologies, and the Electric Power Research Institute.

  4. dc discharge cell for laser optogalvanic spectroscopy

    NASA Technical Reports Server (NTRS)

    Webster, C. R.

    1983-01-01

    A dc electrical discharge cell for laser optogalvanic spectroscopy has been designed and tested. Signal optimization is achieved through the use of adjustable electrode positions and an orthogonal geometry between the probe laser and the discharge axis. Results are presented for visible dye laser and infrared diode laser studies of selected neutral, radical, and ion species.

  5. Manufacturing development of DC-10 advanced rudder

    NASA Technical Reports Server (NTRS)

    Cominsky, A.

    1979-01-01

    The design, manufacture, and ground test activities during development of production methods for an advanced composite rudder for the DC-10 transport aircraft are described. The advanced composite aft rudder is satisfactory for airline service and a cost saving in a full production manufacturing mode is anticipated.

  6. NASA DC-8 Airborne Scanning Lidar Sensor Development

    NASA Technical Reports Server (NTRS)

    Nielsen, Norman B.; Uthe, Edward E.; Kaiser, Robert D.; Tucker, Michael A.; Baloun, James E.; Gorordo, Javier G.

    1996-01-01

    The NASA DC-8 aircraft is used to support a variety of in-situ and remote sensors for conducting environmental measurements over global regions. As part of the atmospheric effects of aviation program (AEAP) the DC-8 is scheduled to conduct atmospheric aerosol and gas chemistry and radiation measurements of subsonic aircraft contrails and cirrus clouds. A scanning lidar system is being developed for installation on the DC-8 to support and extend the domain of the AEAP measurements. Design and objectives of the DC-8 scanning lidar are presented.

  7. NASA DC-8 airborne scanning LIDAR sensor development

    SciTech Connect

    Nielsen, N.B.; Uthe, E.E.; Kaiser, R.D.

    1996-11-01

    The NASA DC-8 aircraft is used to support a variety of in-situ and remote sensors for conducting environmental measurements over global regions. As part of the atmospheric effects of aviation program (AEAP) the DC-8 is scheduled to conduct atmospheric aerosol and gas chemistry and radiation measurements of subsonic aircraft contrails and cirrus clouds. A scanning lidar system is being developed for installation on the DC-8 to support and extend the domain of the AEAP measurements. Design and objectives of the DC-8 scanning lidar are presented. 4 figs.

  8. High-gain inverters based on WSe2 complementary field-effect transistors.

    PubMed

    Tosun, Mahmut; Chuang, Steven; Fang, Hui; Sachid, Angada B; Hettick, Mark; Lin, Yongjing; Zeng, Yuping; Javey, Ali

    2014-05-27

    In this work, the operation of n- and p-type field-effect transistors (FETs) on the same WSe2 flake is realized,and a complementary logic inverter is demonstrated. The p-FET is fabricated by contacting WSe2 with a high work function metal, Pt, which facilities hole injection at the source contact. The n-FET is realized by utilizing selective surface charge transfer doping with potassium to form degenerately doped n+ contacts for electron injection. An ON/OFF current ratio of >10(4) is achieved for both n- and p-FETs with similar ON current densities. A dc voltage gain of >12 is measured for the complementary WSe2 inverter. This work presents an important advance toward realization of complementary logic devices based on layered chalcogenide semiconductors for electronic applications. PMID:24684575

  9. VSI-PWM rectifier/inverter system with a reduced switch count

    SciTech Connect

    Kim, G.T.; Lipo, T.A.

    1995-12-31

    A current controlled VSI-PWM rectifier and inverter with capacitor dc link is regarded as one of the most promising structures for three-phase to three-phase power conversion. This type of converter normally requires twelve switches for a rectifier and inverter composed of self turn-off switch such as a bi-polar transistor or IGBT with an antiparallel diode. In this paper, a new three-phase to three-phase converter for ac motor drives is proposed. The proposed converter employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow. This paper describes the feasibility and the operational limitations of the proposed structure. A mathematical model of the system is derived using generalized modulation theory and experimental results for steady state and dynamic behavior are presented to verify the developed model.

  10. A Five-Leg Inverter for Driving a Traction Motor and a Compressor Motor

    SciTech Connect

    Su, Gui-Jia; Hsu, John S

    2006-01-01

    This paper presents an integrated inverter for speed control of a traction motor and a compressor motor to reduce the compressor drive cost in EV/HEV applications. The inverter comprises five phase-legs; three of which are for control of a three-phase traction motor and the remaining two for a two-phase compressor motor with three terminals. The common terminal of the two-phase motor is tied to the neutral point of the three-phase traction motor to eliminate the requirement of a third phase leg. Further cost savings are made possible by sharing the switching devices, dc bus filter capacitors, gate drive power supplies, and control circuit. Simulation and experimental results are included to verify that speed control of the two motors is independent from each other.

  11. 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.

  12. SUBCONTRACT REPORT: DC-DC Converter for Fuel Cell and Hybrid Vehicles

    SciTech Connect

    Marlino, Laura D; Zhu, Lizhi

    2007-07-01

    The goal of this project is to develop and fabricate a 5kW dc-dc converter with a baseline 14V output capability for fuel cell and hybrid vehicles. The major objectives for this dc-dc converter technology are to meet: Higher efficiency (92%); High coolant temperature,e capability (105 C); High reliability (15 Years/150,000miles); Smaller volume (5L); Lower weight (6kg); and Lower cost ($75/kW). The key technical challenge for these converters is the 105 C coolant temperatures. The power switches and magnetics must be designed to sustain these operating temperatures reliably, without a large cost/mass/volume penalty.

  13. Digital logic with YBa sub 2 Cu sub 3 O sub 7 minus x dc SQUIDs

    SciTech Connect

    Schwarzbek, S.M.; Davidheiser, R.A.; Fischer, G.R.; Luine, J.A.; Schneier, N.J. )

    1991-08-12

    We report the operation of AND, EXOR, EXNOR, and inverting gates in a circuit architecture suitable for the set of all Boolean gates. Series arrays of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} dc superconducting quantum interference devices with integrated coils exhibit sufficient modulation to allow low-speed tests demonstrating gate logic, and lack of oscillation or latching. The best inverter operated (without load) at 36 {mu}V, with 2 nW of gate dissipation.

  14. DC current monitor

    NASA Technical Reports Server (NTRS)

    Canter, Stanley (Inventor)

    1991-01-01

    A non-intrusive DC current monitor is presented which emulates the theoretical operation of an AC transformer. A conductor, carrying the current to be measured, acts as the primary of a DC current transformer. This current is passed through the center of a secondary coil, and core positioned thereabout, and produces a magnetic flux which induces a current in the secondary proportional to the current flowing in the primary. Means are provided to periodically reset the transformer core such that the measurement inaccuracies associated with core saturation are obviated. A reset current is caused to periodically flow through the secondary coil which produces a magnetic flux oppositely polarized to the flux created by the current in the primary, thus allowing ongoing measurements to be made.

  15. Pre-IGY Ionosphere Over Washington D.C

    NASA Astrophysics Data System (ADS)

    Rice, D. D.; Sojka, J. J.; Eccles, J. V.; Hunsucker, R. D.

    2012-12-01

    A data recovery study has been sponsored by the NSF to determine how successfully the ionosphere during a pre-IGY era can be inferred from archived ionogram films. This pilot study targets the Washington, DC ionosonde WA938 located at Ft. Belvoir in Fairfax, VA (38.7° N, -77.1° E). The focus of the study is 1951, 61 years ago, or about 5 1/2 solar cycles ago. The ionosonde was a model C-3 designed by the National Bureau of Standards (NBS). Ionograms were taken at approximately six per hour, but not uniformly spaced in time. These were recorded on an extended frame 35 mm film. Between 2-4 weeks of ionograms were recorded on a single film reel. These films were archived at the NOAA's National Geophysical Data Center (NGDC), also known as a World Data Center . Over the past five years, NGDC has been able to digitize several months from selected years of these films. These digitized ionogram images are the starting point for the ionospheric data analysis for this study. SEC has developed an image processing technique called the Expert System for Ionogram Reduction (ESIR), which has been patented [Sojka et al. 2009]. This software was developed specifically to recognize and invert an ionogram from a photographic image, producing an equivalent ionospheric electron density profile. The recognition of both virtual height and frequency axes in these ionogram photos is discussed. We demonstrate how we can validate and calibrate these scales independent of the ionosonde's virtual height and frequency markings. Examples during several months of 1951 of the automated ESIR ionogram reduction will be provided. These examples will be presented in the context of how the mid-latitude ionosphere over Washington DC in 1951 compares with the present-day ionosphere. Limitations in the data extraction are discussed from a point of view of how they might affect confidence in the inferred long-term trends in the ionosphere. Reference: Sojka J. J., D. C. Thompson, D. D. Rice (2009

  16. Power inversion design for ocean wave energy harvesting

    NASA Astrophysics Data System (ADS)

    Talebani, Anwar N.

    The needs for energy sources are increasing day by day because of several factors, such as oil depletion, and global climate change due to the higher level of CO2, so the exploration of various renewable energy sources is very promising area of study. The available ocean waves can be utilized as free source of energy as the water covers 70% of the earth surface. This thesis presents the ocean wave energy as a source of renewable energy. By addressing the problem of designing efficient power electronics system to deliver 5 KW from the induction generator to the grid with less possible losses and harmonics as possible and to control current fed to the grid to successfully harvest ocean wave energy. We design an AC-DC full bridge rectifier converter, and a DC-DC boost converter to harvest wave energy from AC to regulated DC. In order to increase the design efficiency, we need to increase the power factor from (0.5-0.6) to 1. This is accomplished by designing the boost converter with power factor correction in continues mode with RC circuit as an input to the boost converter power factor correction. This design results in a phase shift between the input current and voltage of the full bridge rectifier to generate a small reactive power. The reactive power is injected to the induction generator to maintain its functionality by generating a magnetic field in its stator. Next, we design a single-phase pulse width modulator full bridge voltage source DC-AC grid-tied mode inverter to harvest regulated DC wave energy to AC. The designed inverter is modulated by inner current loop, to control current injected to the grid with minimal filter component to maintain power quality at the grid. The simulation results show that our design successfully control the current level fed to the grid. It is noteworthy that the simulated efficiency is higher than the calculated one since we used an ideal switch in the simulated circuit.

  17. Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification

    PubMed Central

    Brewer, Bonita J.; Payen, Celia; Di Rienzi, Sara C.; Higgins, Megan M.; Ong, Giang; Dunham, Maitreya J.; Raghuraman, M. K.

    2015-01-01

    DNA replication errors are a major driver of evolution—from single nucleotide polymorphisms to large-scale copy number variations (CNVs). Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model—Origin-Dependent Inverted-Repeat Amplification (ODIRA)—proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error—the ligation of leading and lagging nascent strands to create “closed” forks—can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent—a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins of

  18. Design, manufacture, and test of coolant pump-motor assembly for Brayton power conversion system

    NASA Technical Reports Server (NTRS)

    Gabacz, L. E.

    1973-01-01

    The design, development, fabrication, and testing of seven coolant circulating pump-motor assemblies are discussed. The pump-motor assembly is driven by the nominal 44.4-volt, 400-Hz, 3-phase output of a nominal 56-volt dc input inverter. The pump-motor assembly will be used to circulate Dow Corning 200 liquid coolant for use in a Brayton cycle space power system. The pump-motor assembly develops a nominal head of 70 psi at 3.7 gpm with an over-all efficiency of 26 percent. The design description, drawings, photographs, reliability results, and developmental and acceptance test results are included.

  19. Addressable inverter matrix for process and device characterization

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Sayah, H. R.

    1985-01-01

    The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold vltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

  20. Addressable inverter matrix for process and device characterization

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Sayah, H. R.

    1985-01-01

    The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated in this study, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold voltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

  1. A new low-cost, fully fault-protected PWM-VSI inverter with true phase-current information

    SciTech Connect

    Blaabjerg, F.; Pedersen, J.K.

    1997-01-01

    This paper proposes a new topology for a low-cost three-phase pulse width modulation (PWM) VSI inverter where a true phase current information exists with the use of only one current sensor in the dc link. The topology also has the benefits of full protection of the inverter such as short circuits in the dc link, output phase faults, and output earth faults. Previously suggested methods have problems at low speed in detecting the phase current, but by the use of space vector modulation in a double-sided implementation, the PWM-pulses are adjusted so true information about the phase current exists even at very low speed. The dc link current is sampled twice during one switching period, and it is proposed to sample in the center of the PWM-pulses to obtain a real average phase current. The effects of blanking-time and overmodulation are also discussed. The strategy is implemented in a 16-b microcontroller, and the test results show the technique is useful in the whole speed range. It is concluded by the use of the proposed topology that only one current sensor will be necessary in the future for PWM-VSI inverters.

  2. Design Papers for the National Assessment of Vocational Education. Proceedings of the National Conference on the Condition of Vocational Education (Washington, DC, September 11-12, 1986).

    ERIC Educational Resources Information Center

    Policy Studies Associates, Inc., Washington, DC.

    This volume contains the following 19 papers delivered at a national conference on the design of assessment of vocational education: "The National Assessment of Vocational Education: An Introduction" (Gilbert T. Sewall); "Vocational Education--Opportunity and Challenge: Perspectives on the National Assessment of Vocational Education" (Robert E.…

  3. Construction and characterization of spherical Si solar cells combined with SiC electric power inverter

    NASA Astrophysics Data System (ADS)

    Oku, Takeo; Matsumoto, Taisuke; Hiramatsu, Kouichi; Yasuda, Masashi; Shimono, Akio; Takeda, Yoshikazu; Murozono, Mikio

    2015-02-01

    Spherical silicon (Si) photovoltaic solar cell systems combined with an electric power inverter using silicon carbide (SiC) field-effect transistor (FET) were constructed and characterized, which were compared with an ordinary Si-based converter. The SiC-FET devices were introduced in the direct current-alternating current (DC-AC) converter, which was connected with the solar panels. The spherical Si solar cells were used as the power sources, and the spherical Si panels are lighter and more flexible compared with the ordinary flat Si solar panels. Conversion efficiencies of the spherical Si solar cells were improved by using the SiC-FET.

  4. Characterization of the Ecosole HCPV tracker and single module inverter

    NASA Astrophysics Data System (ADS)

    Carpanelli, Maurizio; Borelli, Gianni; Verdilio, Daniele; De Nardis, Davide; Migali, Fabrizio; Cancro, Carmine; Graditi, Giorgio

    2015-09-01

    BECAR, the Beghelli group's R&D company, is leading ECOSOLE (Elevated COncentration SOlar Energy), one of the largest European Demonstration projects in solar photovoltaic. ECOSOLE, started in 2012, is focused on the study, design, and realization of new HCPV generator made of high efficiency PV modules equipped with SoG (Silicone on Glass) fresnel lenses and III-V solar cells, and a low cost matched solar tracker with distributed inverters approach. The project also regards the study and demonstration of new high throughput methods for the industrial large scale productions, at very low manufacturing costs. This work reports the description of the characterization of the tracker and single module.

  5. A diagonally inverted LU implicit multigrid scheme

    NASA Technical Reports Server (NTRS)

    Yokota, Jeffrey W.; Caughey, David A.; Chima, Rodrick V.

    1988-01-01

    A new Diagonally Inverted LU Implicit scheme is developed within the framework of the multigrid method for the 3-D unsteady Euler equations. The matrix systems that are to be inverted in the LU scheme are treated by local diagonalizing transformations that decouple them into systems of scalar equations. Unlike the Diagonalized ADI method, the time accuracy of the LU scheme is not reduced since the diagonalization procedure does not destroy time conservation. Even more importantly, this diagonalization significantly reduces the computational effort required to solve the LU approximation and therefore transforms it into a more efficient method of numerically solving the 3-D Euler equations.

  6. 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.

  7. Frequency Domain Analysis of Beat-Less Control Method for Converter-Inverter Driving Systems Applied to AC Electric Cars

    NASA Astrophysics Data System (ADS)

    Kimura, Akira

    In inverter-converter driving systems for AC electric cars, the DC input voltage of an inverter contains a ripple component with a frequency that is twice as high as the line voltage frequency, because of a single-phase converter. The ripple component of the inverter input voltage causes pulsations on torques and currents of driving motors. To decrease the pulsations, a beat-less control method, which modifies a slip frequency depending on the ripple component, is applied to the inverter control. In the present paper, the beat-less control method was analyzed in the frequency domain. In the first step of the analysis, transfer functions, which revealed the relationship among the ripple component of the inverter input voltage, the slip frequency, the motor torque pulsation and the current pulsation, were derived with a synchronous rotating model of induction motors. An analysis model of the beat-less control method was then constructed using the transfer functions. The optimal setting of the control method was obtained according to the analysis model. The transfer functions and the analysis model were verified through simulations.

  8. High voltage series resonant inverter ion engine screen supply. [SCR series resonant inverter for space applications

    NASA Technical Reports Server (NTRS)

    Biess, J. J.; Inouye, L. Y.; Shank, J. H.

    1974-01-01

    A high-voltage, high-power LC series resonant inverter using SCRs has been developed for an Ion Engine Power Processor. The inverter operates within 200-400Vdc with a maximum output power of 2.5kW. The inverter control logic, the screen supply electrical and mechanical characteristics, the efficiency and losses in power components, regulation on the dual feedback principle, the SCR waveforms and the component weight are analyzed. Efficiency of 90.5% and weight density of 4.1kg/kW are obtained.

  9. Nearly Unity Power-Factor of the Modular Three-Phase AC to DC Converter with Minimized DC Bus Capacitor

    NASA Astrophysics Data System (ADS)

    Chunkag, Viboon; Kamnarn, Uthen

    The analysis and design of nearly unity power-factor and fast dynamic response of the modular three-phase ac to dc converter using three single-phase isolated SEPIC rectifier modules with minimized dc bus capacitor is discussed, based on power balance control technique. The averaged small-signal technique is used to obtain the inductor current compensator, thus resulting in the output impedance and audio susceptibility become zero, that is, the output voltage of the converter presented in this paper is independent of the variations of the dc load current and the utility voltage. The proposed system significantly improves the dynamic response of the converter to load steps with minimized dc bus capacitor for Distributed Power System (DPS). A 600W prototype modular three-phase ac to dc converter comprising three 200W single-phase SEPIC rectifier modules with the proposed control scheme has been designed and implemented. The proposed system is confirmed by experimental implementation.

  10. Design considerations for high-altitude, long-endurance, microwave-powered aircraft. M.S. Thesis - George Washington Univ., Washington, D.C.

    NASA Technical Reports Server (NTRS)

    Nguyen, H. Q.

    1985-01-01

    The sizing and performance analyses have been conducted in the design of long-endurance, high-altitude airplanes. These airplanes receive power either continuously beamed from a phased array transmitter or intermittently beamed from a dish transmitter. Results are presented for the cases of flight in zero wind speed and nonzero wind speed. Sensitivity studies indicate that the vehicle size is relatively insensitive to changes in the transmitter size. Cost estimates were made using models that excluded the airplane cost. Using a reference payload, results obtained from array and dish configurations were compared. Comparisons showed savings in cost as well as smaller vehicle sizes when an array transmitter was used.

  11. Fast response double series resonant high-voltage DC-DC converter

    NASA Astrophysics Data System (ADS)

    Lee, S. S.; Iqbal, S.; Kamarol, M.

    2012-10-01

    In this paper, a novel double series resonant high-voltage dc-dc converter with dual-mode pulse frequency modulation (PFM) control scheme is proposed. The proposed topology consists of two series resonant tanks and hence two resonant currents flow in each switching period. Moreover, it consists of two high-voltage transformer with the leakage inductances are absorbed as resonant inductor in the series resonant tanks. The secondary output of both transformers are rectified and mixed before supplying to load. In the resonant mode operation, the series resonant tanks are energized alternately by controlling two Insulated Gate Bipolar Transistor (IGBT) switches with pulse frequency modulation (PFM). This topology operates in discontinuous conduction mode (DCM) with all IGBT switches operating in zero current switching (ZCS) condition and hence no switching loss occurs. To achieve fast rise in output voltage, a dual-mode PFM control during start-up of the converter is proposed. In this operation, the inverter is started at a high switching frequency and as the output voltage reaches 90% of the target value, the switching frequency is reduced to a value which corresponds to the target output voltage. This can effectively reduce the rise time of the output voltage and prevent overshoot. Experimental results collected from a 100-W laboratory prototype are presented to verify the effectiveness of the proposed system.

  12. Halbach array DC motor/generator

    DOEpatents

    Merritt, B.T.; Dreifuerst, G.R.; Post, R.F.

    1998-01-06

    A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An ``inside-out`` design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then ``switched`` or ``commutated`` to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives. 17 figs.

  13. Halbach array DC motor/generator

    DOEpatents

    Merritt, Bernard T.; Dreifuerst, Gary R.; Post, Richard F.

    1998-01-01

    A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An "inside-out" design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then "switched" or "commutated" to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives.

  14. Modelling of Classical and Rotary Inverted Pendulum Systems - A Generalized Approach

    NASA Astrophysics Data System (ADS)

    Jadlovský, Slávka; Sarnovský, Ján

    2013-01-01

    The purpose of this paper is to present the design and program implementation of a general procedure which yields the mathematical model for a classical or rotary inverted pendulum system with an arbitrary number of pendulum links. Lagrange equations of the second kind with an integrated Rayleigh dissipation function are employed in model design, and the energetic balance relations, derived for the base and all pendulum links in a generalized (n-link) classical and rotary inverted pendulum system, are implemented in form of symbolic MATLAB functions and a MATLAB GUI application. The validity and accuracy of motion equations generated by the application are demonstrated by evaluating the open-loop responses of simulation models of classical double and rotary single inverted pendulum.

  15. 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.

  16. Dynamic maneuvers with a mobile inverted pendulum

    NASA Astrophysics Data System (ADS)

    Pogue, Edward

    A mobile inverted pendulum (MIP) type robot was constructed to test the feasibility of performing high speed, dynamic maneuvers. Techniques were developed for line following and to achieve high speed motion with a MIP. The results indicate that the speeds necessary for the maneuver can be achieved, and the groundwork is laid for further experimentation.

  17. A Prefix Trie Index for Inverted Files.

    ERIC Educational Resources Information Center

    Nelson, Michael J.

    1997-01-01

    Applies a prefix trie index, or trie hashing, to the problem of providing fast search times, fast load times, and fast update properties in a bibliographic or full-text retrieval system with inverted files. Statistics are given for a test database consisting of an online catalog at the University of Western Ontario. (Author/LRW)

  18. The Internet and the Inverted Classroom.

    ERIC Educational Resources Information Center

    Lage, Maureen J.; Platt, Glenn

    2000-01-01

    Describes a Web site that is for an undergraduate principles of microeconomics course and a main component of "The Inverted Classroom" in which lectures take place outside of class. Explains that the Web site is divided into four sections: (1) the classroom; (2) the desk; (3) the coffee shop; and (4) the library. (CMK)

  19. High performance dc-dc conversion with voltage multipliers

    NASA Technical Reports Server (NTRS)

    Harrigill, W. T.; Myers, I. T.

    1974-01-01

    The voltage multipliers using capacitors and diodes first developed by Cockcroft and Walton in 1932 were reexamined in terms of state of the art fast switching transistors and diodes, and high energy density capacitors. Because of component improvements, the voltage multiplier, used without a transformer, now appears superior in weight to systems now in use for dc-dc conversion. An experimental 100-watt 1000-volt dc-dc converter operating at 100 kHz was built, with a component weight of about 1 kg/kW. Calculated and measured values of output voltage and efficiency agreed within experimental error.

  20. Improved DC Gun Insulator

    SciTech Connect

    M.L. Neubauer, K.B. Beard, R. Sah, C. Hernandez-Garcia, G. Neil

    2009-05-01

    Many user facilities such as synchrotron light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic, creating a buildup of charge and causing eventual puncture. A novel ceramic manufacturing process is proposed. It will incorporate bulk resistivity in the region where it is needed to bleed off accumulated charge caused by highly energetic electrons. This process will be optimized to provide an appropriate gradient in bulk resistivity from the vacuum side to the air side of the HV standoff ceramic cylinder. A computer model will be used to determine the optimum cylinder dimensions and required resistivity gradient for an example RF gun application. A ceramic material example with resistivity gradient appropriate for use as a DC gun insulator will be fabricated by glazing using doping compounds and tested.

  1. Impact of the spacer dielectric constant on parasitic RC and design guidelines to optimize DC/AC performance in 10-nm-node Si-nanowire FETs

    NASA Astrophysics Data System (ADS)

    Hong, Jae-Ho; Lee, Sang-Hyun; Kim, Ye-Ram; Jeong, Eui-Young; Yoon, Jun-Sik; Lee, Jeong-Soo; Baek, Rock-Hyun; Jeong, Yoon-Ha

    2015-04-01

    In this paper, we propose an optimized design for Si-nanowire FETs in terms of spacer dielectric constant (κsp), extension length (LEXT), nanowire diameter (Dnw), and operation voltage (VDD) for the sub-10 nm technology node. Using well-calibrated TCAD simulations and analytic RC models, we have quantitatively evaluated geometry-dependent parasitic series resistances (RSD) and capacitances (Cpara). Compared with low-κ spacers, high-κ spacers exhibit a higher on/off-current ratio with a lower RSD, but show severe degradation in their AC performance owing to a higher Cpara. Considering the trade-off between RSD and Cpara, optimal geometry-dependent κsp values at various supply voltages (VDD) are determined using gate delay (CV/I) and current-gain cutoff frequency (fT). We found that as LEXT and VDD decrease and Dnw increases, the optimal κsp value shifts from the high-κ to low-κ regime.

  2. Sensorless Vector Control of IPMSM with DC Link Current Measurement at Low Speeds

    NASA Astrophysics Data System (ADS)

    Kubota, Hisao; Nakagawa, Satoshi; Kobayashi, Takayuki

    This paper presents a method of estimating pole position of interior permanent magnet synchronous motors, IPMSMs. The proposed method estimates the pole position at low speeds and standstill by measuring only the DC link current of the inverter. The pole position is estimated by using the saliency of the IPMSMs. In order to detect the saliency, the three phase triangular carrier waves are used. The DC link current is measured at tops and bottoms of the carrier waves. Experimentation is performed to confirm the validity of the proposed method.

  3. Progress on advanced dc and ac induction drives for electric vehicles

    NASA Technical Reports Server (NTRS)

    Schwartz, H. J.

    1982-01-01

    Progress is reported in the development of complete electric vehicle propulsion systems, and the results of tests on the Road Load Simulator of two such systems representative of advanced dc and ac drive technology are presented. One is the system used in the DOE's ETV-1 integrated test vehicle which consists of a shunt wound dc traction motor under microprocessor control using a transistorized controller. The motor drives the vehicle through a fixed ratio transmission. The second system uses an ac induction motor controlled by transistorized pulse width modulated inverter which drives through a two speed automatically shifted transmission. The inverter and transmission both operate under the control of a microprocessor. The characteristics of these systems are also compared with the propulsion system technology available in vehicles being manufactured at the inception of the DOE program and with an advanced, highly integrated propulsion system upon which technology development was recently initiated.

  4. View of Inverted Siphon crossing Hot Water (or White) Canyon. ...

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

    View of Inverted Siphon crossing Hot Water (or White) Canyon. Looking northeast - Childs-Irving Hydroelectric Project, Irving System, Inverted Siphon, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  5. Radiation dependence of inverter propagation delay from timing sampler measurements

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Blaes, B. R.; Lin, Y.-S.

    1989-01-01

    A timing sampler consisting of 14 four-stage inverter-pair chains with different load capacitances was fabricated in 1.6-micron n-well CMOS and irradiated with cobalt-60 at 10 rad(Si)/s. For this CMOS process the measured results indicate that the rising delay increases by about 2.2 ns/Mrad(Si) and the falling delay increase is very small, i.e., less than 300 ps/Mrad(Si). The amount of radiation-induced delay depends on the size of the load capacitance. The maximum value observed for this effect was 5.65 ns/pF-Mrad(Si). Using a sensitivity analysis, the sensitivity of the rising delay to radiation can be explained by a simple timing model and the radiation sensitivity of dc MOSFET parameters. This same approach could not explain the insensitivity of the falling delay to radiation. This may be due to a failure of the timing model and/or trapping effects.

  6. High-power, null-type, inverted pendulum thrust stand.

    PubMed

    Xu, Kunning G; Walker, Mitchell L R

    2009-05-01

    This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error due to deflection of thrust. The thrust stand position serves as the input to the null-circuit feedback control system and the output is the current to an electromagnetic actuator. Mechanical oscillations are actively damped with an electromagnetic damper. A closed-loop inclination system levels the stand while an active cooling system minimizes thermal effects. The thrust stand incorporates an in situ calibration rig. The thrust of a 3.4 kW Hall thruster is measured for thrust levels up to 230 mN. The uncertainty of the thrust measurements in this experiment is +/-0.6%, determined by examination of the hysteresis, drift of the zero offset and calibration slope variation. PMID:19485530

  7. Mobile Inverted Constructivism: Education of Interaction Technology in Social Media

    ERIC Educational Resources Information Center

    Chai, Jia-Xiang; Fan, Kuo-Kuang

    2016-01-01

    The combination of social media and invert teaching is a new path to inverting interation technology education and reconstructing the curriculum of context. In this paper, based on the theory of constructivism learning, a model named Mobile Inverted Constructivism (MIC) is provided. Moreover, in view of the functional quality of social media in…

  8. Motor/Generator and Inverter Characterization for Flywheel System Applications

    NASA Technical Reports Server (NTRS)

    Tamarcus, Jeffries L.

    2004-01-01

    The Advanced Electrical Systems Development Branch at NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheels systems for satellite energy storage and attitude applications. These flywheels will serve as replacement for chemical nickel hydrogen, nickel cadmium batteries and gyroscopic wheels. The advantages of using flywheel systems for energy storage on satellites are high energy density, high power density, long life, deep depth of discharge, and broad operating temperature ranges. A flywheel system for space applications consist of a number of flywheel modules, the motor/generator and magnetic bearing, and an electronics package. The motor/generator electronics package includes a pulse-width modulated inverter that drives the flywheel permanent magnet motor/generator located at one end of the shaft. This summer, I worked under the direct supervision of my mentor, Walter Santiago, and the goal for this summer was to characterize motor generator and inverter attributes in order to increase their viability as a more efficient energy storage source for space applications. To achieve this goal, magnetic field measurements around the motor/generator permanent magnet and the impedance of the motor/generator three phase windings were characterized, and a recreation of the inverter pulse width modulated control system was constructed. The Flywheel modules for space use are designed to maximize energy density and minimize loss, and attaining these values will aid in locating and reducing losses within the flywheel system as a whole, making flywheel technology more attractive for use as energy storage in future space applications.

  9. A DC Transformer

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.; Ihlefeld, Curtis M.; Starr, Stanley O.

    2013-01-01

    A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both de devices, such that the output voltage of a de power supply can be stepped up (or down) with a corresponding step down (or up) in current. The basic theory for this device is developed, performance predictions are made, and the results from a small prototype are presented. Based on demonstrated technology in the literature, this de transformer should be scalable to low megawatt levels, but it is more suited to high current than high voltage applications. Significant development would be required before it could achieve the kilovolt levels needed for de power transmission.

  10. A Plasma-Based DC-DC Electrical Transformer

    NASA Astrophysics Data System (ADS)

    Nebel, Richard; Finn, John

    2013-10-01

    Previous work has indicated that it may be possible to make DC-DC electrical transformers using plasmas. The mechanism is an MHD electromagnetic relaxation process induced by helical electrodes. This process is now being tested on the Bismark device at Tibbar Technologies.

  11. 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.

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

    SciTech Connect

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

    2014-09-04

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

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

    DOE PAGESBeta

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

    2014-09-04

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

  15. PWM Inverter with Voltage Boosters with Regenerating Capability Augmented by Electric Double-Layer Capacitor

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kichiro; Imakiire, Akihiro; Iimori, Kenichi

    An interior permanent magnet (IPM) motor drive system which has regenerating capability augmented by electric double-layer capacitors (EDLCs) is proposed. In the proposed system, EDLCs are arranged in series with batteries so that a lesser number of the EDLCs and batteries will be required. The proposed system has two bi-directional voltage boosters: one is for both the batteries and EDLCs to control the dc-link voltage of a PWM inverter and the other is for only the EDLCs and is used to control the energy flow from and to the EDLCs. In this paper, a strategy to control the energy flow to and from the EDLCs is explained and its effectiveness is confirmed by simulation and experimental results. Furthermore, the efficiencies of the voltage booster, inverter, PM motor, and whole system are measured for the system with the basic configuration, i.e., which consists of only one bi-directional voltage booster and PWM inverter. Then, the steady-state characteristics are determined. Finally, the efficiency of the voltage boosters in the proposed system is determined, and the advantage of the proposed PM motor drive system is discussed.

  16. Multiple output zero-current switching switched-capacitor bidirectional dc-dc converter

    NASA Astrophysics Data System (ADS)

    Lee, Yuang-Shung; Ko, Yi-Pin; Chi, Chien-An

    2010-08-01

    The proposed circuit is a multiple output quasi-resonant (QR) zero-current switching (ZCS) switched-capacitor (SC) converter with a bidirectional power flow control conversion scheme. The principles of the proposed multiple output QR ZCS SC bidirectional dc-dc converter are described using a detailed circuit model for analysis. Simulation and experimental results are carried out to verify the validity and the soft switching performance of the proposed converter. The maximum efficiency achievable is about 94 and 92% for the forward and reverse power flow control schemes, respectively. The output voltage can be regulated by changing the switching frequency for the designed compensated closed-loop controller.

  17. Lessons learned: DC-X

    NASA Technical Reports Server (NTRS)

    Steinmeyer, D. A.

    1996-01-01

    The DC-X was conceived and developed specifically to lay the ground work for significantly lowering the cost of space operations. The system design was based on an initial set of program goals and a finite, limited set of resources. The goal in its simplest terms was to demonstrate vertical landing after rotation of the vehicle from a nose-first to an engines-first altitude. Finite resources actually drove the selection of a robust design to reduce fabrication and preflight testing costs. The result was a system with a large amount of flexibility which allowed expansion of the test goals as the system, and test program, evolved. The use of the vehicle flight computer interfacing with the ground control system for flight crew training was also not an initial concept. However, by defining an architecture for the system control modes which allowed additions and modifications as learning progressed, the 6 DOF codes used for flight controls software development were transported to the operating system to be used in a simulated flight mode. Flight data reduction was also greatly improved as the program progressed, and the data needs and presentation were refined. The software, avionics hardware, and the FOCC system development proceeded ahead of the vehicle, primarily because most of the hardware elements were existing at the outset of the program. The Built-in-Test (BIT) for avionics and propulsion systems were adequate. Particularly the flight readiness system which verified the vehicle health after engine start and before throttle-up for flight.

  18. A Soft-Switching Inverter for High-Temperature Advanced Hybrid Electric Vehicle Traction Motor Drives

    SciTech Connect

    Lai, Jason; Yu, Wensong; Sun, Pengwei; Leslie, Scott; Prusia, Duane; Arnet, Beat; Smith, Chris; Cogan, Art

    2012-03-31

    The state-of-the-art hybrid electric vehicles (HEVs) require the inverter cooling system to have a separate loop to avoid power semiconductor junction over temperatures because the engine coolant temperature of 105°C does not allow for much temperature rise in silicon devices. The proposed work is to develop an advanced soft-switching inverter that will eliminate the device switching loss and cut down the power loss so that the inverter can operate at high-temperature conditions while operating at high switching frequencies with small current ripple in low inductance based permanent magnet motors. The proposed tasks also include high-temperature packaging and thermal modeling and simulation to ensure the packaged module can operate at the desired temperature. The developed module will be integrated with the motor and vehicle controller for dynamometer and in-vehicle testing to prove its superiority. This report will describe the detailed technical design of the soft-switching inverters and their test results. The experiments were conducted both in module level for the module conduction and switching characteristics and in inverter level for its efficiency under inductive and dynamometer load conditions. The performance will be compared with the DOE original specification.

  19. How Learning in an Inverted Classroom Influences Cooperation, Innovation and Task Orientation

    ERIC Educational Resources Information Center

    Strayer, Jeremy F.

    2012-01-01

    Recent technological developments have given rise to blended learning classrooms. An inverted (or flipped) classroom is a specific type of blended learning design that uses technology to move lectures outside the classroom and uses learning activities to move practice with concepts inside the classroom. This article compares the learning…

  20. 76 FR 13926 - Airworthiness Directives; The Boeing Company Model DC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8-32...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-15

    ... required by AD 2008-25-05, Amendment 39-15763 (73 FR 78936, December 24, 2008), for Principal Structural... Policies and Procedures (44 FR 11034, February 26, 1979), and 3. Will not have a significant economic...-8-21, DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, DC-8-43, DC-8-51, DC-8-52, DC-8-53,......

  1. Minimizing Gravity Sag of a Large Mirror with an Inverted Hindle-Mount

    NASA Technical Reports Server (NTRS)

    Robinson, David W.; Powers, Edward I. (Technical Monitor)

    2000-01-01

    A method of minimizing the optical distortion from gravity sag on a suspended large autocollimating flat mirror has been devised. This method consists of an inverted nine-point Hindle-Mount. A conventional Hindle-mount is located underneath a sky-viewing mirror and is primarily under compression loads from the weight of the mirror. It is not suitable for the situation where the mirror is viewing the ground, since a mirror would tend to fall out of the mount when in an inverted position. The inverted Hindle-Mount design consists of bonded joints on the backside of the mirror that allow the mirror to be held or suspended above an object to be viewed. This ability is useful in optical setups such as a calibration test where a flat mirror is located above a telescope so that the telescope may view a known optic.

  2. Electronic Document Management Using Inverted Files System

    NASA Astrophysics Data System (ADS)

    Suhartono, Derwin; Setiawan, Erwin; Irwanto, Djon

    2014-03-01

    The amount of documents increases so fast. Those documents exist not only in a paper based but also in an electronic based. It can be seen from the data sample taken by the SpringerLink publisher in 2010, which showed an increase in the number of digital document collections from 2003 to mid of 2010. Then, how to manage them well becomes an important need. This paper describes a new method in managing documents called as inverted files system. Related with the electronic based document, the inverted files system will closely used in term of its usage to document so that it can be searched over the Internet using the Search Engine. It can improve document search mechanism and document save mechanism.

  3. On the uncontrollable damped triple inverted pendulum

    NASA Astrophysics Data System (ADS)

    Su, H.; Woodham, C. A.

    2003-02-01

    In this paper, the controllability of the damped triple inverted pendulum is investigated. The work is concerned with the form of the cancelling pole and zero which appear in the transfer functions of an uncontrollable system, and follows on from earlier work on the damped double inverted pendulum. The investigation considers first the cases where only one of the three arm frictions is non-zero, and then explores the cases when two of the three arm frictions are non-zero. Due to the complexity of this problem, and the difficulties with the symbolic manipulation software, exploratory numerical investigations have been carried out to facilitate the symbolic investigations, all of which are reported here.

  4. Micro-inverter solar panel mounting

    DOEpatents

    Morris, John; Gilchrist, Phillip Charles

    2016-02-02

    Processes, systems, devices, and articles of manufacture are provided. Each may include adapting micro-inverters initially configured for frame-mounting to mounting on a frameless solar panel. This securement may include using an adaptive clamp or several adaptive clamps secured to a micro-inverter or its components, and using compressive forces applied directly to the solar panel to secure the adaptive clamp and the components to the solar panel. The clamps can also include compressive spacers and safeties for managing the compressive forces exerted on the solar panels. Friction zones may also be used for managing slipping between the clamp and the solar panel during or after installation. Adjustments to the clamps may be carried out through various means and by changing the physical size of the clamps themselves.

  5. The Invertible Double of Elliptic Operators

    NASA Astrophysics Data System (ADS)

    Booss-Bavnbek, Bernhelm; Lesch, Matthias

    2009-02-01

    First, we review the Dirac operator folklore about basic analytic and geometrical properties of operators of Dirac type on compact manifolds with smooth boundary and on closed partitioned manifolds and show how these properties depend on the construction of a canonical invertible double and are related to the concept of the Calderón projection. Then we summarize a recent construction of a canonical invertible double for general first order elliptic differential operators over smooth compact manifolds with boundary. We derive a natural formula for the Calderón projection which yields a generalization of the famous Cobordism Theorem. We provide a list of assumptions to obtain a continuous variation of the Calderón projection under smooth variation of the coefficients. That yields various new spectral flow theorems. Finally, we sketch a research program for confining, respectively closing, the last remaining gaps between the geometric Dirac operator type situation and the general linear elliptic case.

  6. Maskless inverted pyramid texturization of silicon.

    PubMed

    Wang, Yan; Yang, Lixia; Liu, Yaoping; Mei, Zengxia; Chen, Wei; Li, Junqiang; Liang, Huili; Kuznetsov, Andrej; Xiaolong, Du

    2015-01-01

    We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists. PMID:26035520

  7. Invertible linear transformations and the Lie algebras

    NASA Astrophysics Data System (ADS)

    Zhang, Yufeng; Tam, Honwah; Guo, Fukui

    2008-07-01

    With the help of invertible linear transformations and the known Lie algebras, a way to generate new Lie algebras is given. These Lie algebras obtained have a common feature, i.e. integrable couplings of solitary hierarchies could be obtained by using them, specially, the Hamiltonian structures of them could be worked out. Some ways to construct the loop algebras of the Lie algebras are presented. It follows that some various loop algebras are given. In addition, a few new Lie algebras are explicitly constructed in terms of the classification of Lie algebras proposed by Ma Wen-Xiu, which are bases for obtaining new Lie algebras by using invertible linear transformations. Finally, some solutions of a (2 + 1)-dimensional partial-differential equation hierarchy are obtained, whose Hamiltonian form-expressions are manifested by using the quadratic-form identity.

  8. Maskless inverted pyramid texturization of silicon

    PubMed Central

    Wang, Yan; Yang, Lixia; Liu, Yaoping; Mei, Zengxia; Chen, Wei; Li, Junqiang; Liang, Huili; Kuznetsov, Andrej; Xiaolong, Du

    2015-01-01

    We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists. PMID:26035520

  9. Intelligent Control of an Inverted Pendulum

    NASA Astrophysics Data System (ADS)

    Rekdalsbakken, Webjorn

    An inverted pendulum represents an unstable system which is excellent for demonstrating the use of feedback control with different kinds of control strategies. In this work state feedback of the inverted pendulum is examined. First a pole placement algorithm is explored. After that artificial intelligence (AI) methods are investigated to better cope with the nonlinearities of the physical model. The technique used is based on a hybrid system combining a neural network (NN) with a genetic algorithm (GA). The NN controller is trained by the GA against the behaviour of the physical model. The results of the training process show that the chromosome population tends to station at a suboptimal level, and that changes in the environmental parameters have to take place to reach a new optimal level. By systematically changing these parameters the NN controller will gradually adapt to the pendulum behaviour.

  10. Inverter testing at Sandia National Laboratories

    SciTech Connect

    Ginn, J.W.; Bonn, R.H.; Sittler, G.

    1997-04-01

    Inverters are key building blocks of photovoltaic (PV) systems that produce ac power. The balance of systems (BOS) portion of a PV system can account for up to 50% of the system cost, and its reliable operation is essential for a successful PV system. As part of its BOS program, Sandia National Laboratories (SNL) maintains a laboratory wherein accurate electrical measurements of power systems can be made under a variety of conditions. This paper outlines the work that is done in that laboratory.

  11. Coaxial inverted geometry transistor having buried emitter

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Cress, S. B.; Dunn, W. R. (Inventor)

    1973-01-01

    The invention relates to an inverted geometry transistor wherein the emitter is buried within the substrate. The transistor can be fabricated as a part of a monolithic integrated circuit and is particularly suited for use in applications where it is desired to employ low actuating voltages. The transistor may employ the same doping levels in the collector and emitter, so these connections can be reversed.

  12. Inverted colloidal quantum dot solar cells.

    PubMed

    Kim, Gi-Hwan; Walker, Bright; Kim, Hak-Beom; Kim, Jin Young; Sargent, Edward H; Park, Jongnam; Kim, Jin Young

    2014-05-28

    An inverted architecture of quantum dot solar cells is demonstrated by introducing a novel ZnO method on top of the PbS CQD film. Improvements in device characteristics stem from constructive optical interference from the ZnO layer that enhances absorption in the PbS CQD layer. Outstanding diode characteristics arising from a superior PbS/ZnO junction provide a further electronic advantage. PMID:24677118

  13. 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.

  14. Handbook of photovoltaic power generating design for introduction

    NASA Astrophysics Data System (ADS)

    1993-03-01

    The purpose of this handbook is to survey the ways to introduce photovoltaic power generation with specifying a certain region of introduction by international cooperation. Various cases of load requirements and load patterns are taken up for more efficient designing of equipment. When actually introducing photovoltaic power generating facilities, more detailed analyses of the situation would be necessary, but this handbook is effective in investigating and comparing basic designs and possible regions of introduction. Presented are illustrated overall designing procedures of photovoltaic power generating facilities and examples in cases of DC load and AC load. This handbook includes assumed load formats, calculation of storage battery capacity, required capacity of photovoltaic cell, selection of photovoltaic cell module, selection of storage battery, selection of inverter, selection of charge controller, list of possible regions, and amounts and durations of insolation in the selected regions, as data for designing photovoltaic power generation for introduction.

  15. Multiple DC, single AC converter with a switched DC transformer

    DOEpatents

    Donnelly, Matthew K.; Hammerstrom, Donald J.

    1997-01-01

    The invention is an improvement of the PASC inverter, wherein the improvements include the reduction from two shorting gates per transformer to one shorting gate per transformer and replacement of active control of the shorting gate with passive control of the shorting gate. Further advantages are obtained through the use of anti-parallel gate sets.

  16. Multiple DC, single AC converter with a switched DC transformer

    DOEpatents

    Donnelly, M.K.; Hammerstrom, D.J.

    1997-05-20

    The invention is an improvement of the PASC inverter, wherein the improvements include the reduction from two shorting gates per transformer to one shorting gate per transformer and replacement of active control of the shorting gate with passive control of the shorting gate. Further advantages are obtained through the use of anti-parallel gate sets. 14 figs.

  17. Amphiphilic invertible polymers: Self-assembly into functional materials driven by environment polarity

    NASA Astrophysics Data System (ADS)

    Hevus, Ivan

    Stimuli-responsive polymers adapt to environmental changes by adjusting their chain conformation in a fast and reversible way. Responsive polymeric materials have already found use in electronics, coatings industry, personal care, and bio-related areas. The current work aims at the development of novel responsive functional polymeric materials by manipulating environment-dependent self-assembly of a new class of responsive macromolecules strategically designed in this study,—amphiphilic invertible polymers (AIPs). Environment-dependent micellization and self-assembly of three different synthesized AIP types based on poly(ethylene glycol) as a hydrophilic fragment and varying hydrophobic constituents was demonstrated in polar and nonpolar solvents, as well as on the surfaces and interfaces. With increasing concentration, AIP micelles self-assemble into invertible micellar assemblies composed of hydrophilic and hydrophobic domains. Polarity-responsive properties of AIPs make invertible micellar assemblies functional in polar and nonpolar media including at interfaces. Thus, invertible micellar assemblies solubilize poorly soluble substances in their interior in polar and nonpolar solvents. In a polar aqueous medium, a novel stimuli-responsive mechanism of drug release based on response of AIP-based drug delivery system to polarity change upon contact with the target cell has been established using invertible micellar assemblies loaded with curcumin, a phytochemical drug. In a nonpolar medium, invertible micellar assemblies were applied simultaneously as nanoreactors and stabilizers for size-controlled synthesis of silver nanoparticles stable in both polar and nonpolar media. The developed amphiphilic nanosilver was subsequently used as seeds to promote anisotropic growth of CdSe semiconductor nanoparticles that have potential in different applications ranging from physics to medicine. Amphiphilic invertible polymers were shown to adsorb on the surface of silica

  18. Energy Balance in DC Arc Plasma Melting Furnace

    NASA Astrophysics Data System (ADS)

    Zhao, Peng; Meng, Yuedong; Yu, Xinyao; Chen, Longwei; Jiang, Yiman; Ni, Guohua; Chen, Mingzhou

    2009-04-01

    In order to treat hazardous municipal solid waste incinerator's (MSWI) fly ash, a new DC arc plasma furnace was developed. Taking an arc of 100 V/1000 A DC as an example, the heat transfer characteristics of the DC arc plasma, ablation of electrodes, heat properties of the fly ash during melting, heat transfer characteristics of the flue gas, and heat loss of the furnace were analyzed based on the energy conservation law, so as to achieve the total heat information and energy balance during plasma processing, and to provide a theoretical basis for an optimized design of the structure and to improve energy efficiency.

  19. A Low-Cost Soft-Switched DC/DC Converter for Solid-Oxide Fuel Cells

    SciTech Connect

    Jason Lai

    2009-03-03

    A highly efficient DC to DC converter has been developed for low-voltage high-current solid oxide fuel cells. The newly developed 'V6' converter resembles what has been done in internal combustion engine that split into multiple cylinders to increase the output capacity without having to increase individual cell size and to smooth out the torque with interleaving operation. The development was started with topology overview to ensure that all the DC to DC converter circuits were included in the study. Efficiency models for different circuit topologies were established, and computer simulations were performed to determine the best candidate converter circuit. Through design optimization including topology selection, device selection, magnetic component design, thermal design, and digital controller design, a bench prototype rated 5-kW, with 20 to 50V input and 200/400V output was fabricated and tested. Efficiency goal of 97% was proven achievable through hardware experiment. This DC to DC converter was then modified in the later stage to converter 35 to 63 V input and 13.8 V output for automotive charging applications. The complete prototype was tested at Delphi with their solid oxide fuel cell test stand to verify the performance of the modified DC to DC converter. The output was tested up to 3-kW level, and the efficiency exceeded 97.5%. Multiple-phase interleaving operation design was proved to be reliable and ripple free at the output, which is desirable for the battery charging. Overall this is a very successful collaboration project between the SECA Core Technology Team and Industrial Team.

  20. Inverted (hobnail) high-grade prostatic intraepithelial neoplasia and invasive inverted pattern

    PubMed Central

    ÖZNUR, MELTEM; KOCA, SEVIM BAYKAL; YILDIZ, PELIN; BAHADIR, BURAK; BEHZATOĞLU, KEMAL

    2015-01-01

    High-grade prostatic intraepithelial neoplasia (HGPIN) is considered to be an important precursor for prostatic adenocarcinoma. The present study aimed to investigate the histological features of the uncommon inverted (hobnail) pattern of HGPIN in transrectal ultrasonographic (TRUS) prostatic needle biopsies from 13 cases. These 13 diagnosed cases of inverted HGPIN were identified out of a total of 2,034 TRUS biopsies (0.63%), obtained from patients suspected to have prostate cancer. The hobnail pattern is comprised of secretory cell nuclei, which are histologically localized at the luminal surface of the prostate gland, rather than the periphery, and exhibit reverse polarity. Histological examinations were performed and the results demonstrated that 5 of the 13 cases exhibited pure inverted histology, while HGPIN was observed to be histologically associated with other patterns in the remaining 8 patients. In addition, an association with adenocarcinoma was identified in 7 of the 13 cases. All 7 carcinomas accompanied by inverted HGPIN were conventional acinar adenocarcinoma cases; of note, for these 7 cases, the Gleason score was 7 for each. One acinar adenocarcinoma case accompanying inverted HGPIN demonstrated hobnail characteristics in large areas of the invasive component. It was observed that nuclei were proliferated in the invasive cribriform glands, which was comparable to that of inverted HGPIN, and were located on the cytoplasmic luminal surface; a similar morphology was also observed in individual glands. In conclusion, the results of the present study suggested that the hobnail HGPIN pattern may be of diagnostic importance due to its high association with adenocarcinoma and the high Gleason scores in the accompanying carcinomas. PMID:26622858

  1. DC-Compensated Current Transformer.

    PubMed

    Ripka, Pavel; Draxler, Karel; Styblíková, Renata

    2016-01-01

    Instrument current transformers (CTs) measure AC currents. The DC component in the measured current can saturate the transformer and cause gross error. We use fluxgate detection and digital feedback compensation of the DC flux to suppress the overall error to 0.15%. This concept can be used not only for high-end CTs with a nanocrystalline core, but it also works for low-cost CTs with FeSi cores. The method described here allows simultaneous measurements of the DC current component. PMID:26805830

  2. Lessons learned, DC-XA

    SciTech Connect

    Steinmeyer, D.

    1997-01-01

    The Delta Clipper-Experimental A (DC-XA) program was conceived and specifically developed to provide a low cost reusable flight vehicle testbed for demonstrating performance and operability testing of advanced technologies required for the development of next generation Reusable Launch Vehicles (RLVs). The three primary program objectives addressed were: To integrate a variety of advanced launch vehicle technology components into the DC-XA flight vehicle testbed. Demonstrate performance, operability, and supportability of Advanced Launch Technologies (ALT) components through ground and flight testing of the DC-XA. Demonstrate rapid prototyping of hardware and software in a combined government, industry cooperative effort. {copyright} {ital 1997 American Institute of Physics.}

  3. A Medium-Voltage Motor Drive with a Modular Multilevel PWM Inverter Part II. Startup Method and Performance

    NASA Astrophysics Data System (ADS)

    Nishimura, Kazutoshi; Hagiwara, Makoto; Akagi, Hirofumi

    This paper presents a medium-voltage motor drive with a modular multilevel PWM inverter, and focuses on a startup method and its performance. It is formed by six modular arms, each of which consists of a cascaded stack of multiple bidirectional chopper-cells. The frequency of the dominant ac-voltage fluctuation is equal to the motor (inverter) frequency. These fluctuations occur in the dc capacitor of each chopper-cell, and the magnitude of the fluctuation is inversely proportional to the motor frequency. Because of the increased voltage fluctuation in low-frequency regions, the so-called “volt-per-hertz control” cannot be applied in motor starting. The startup method proposed in this paper is suitable for a motor drive with the modular multilevel PWM inverter. It enables the motor to produce a startup torque loaded on the motor at an initial amplitude and a fixed frequency of the inverter while taking into account constraints on the motor current and the ac-voltage fluctuation. The validity of the startup method as well as the startup performance is confirmed by experiment and simulation.

  4. 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.

  5. A Compact, Soft-Switching DC-DC Converter for Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Button, Robert; Redilla, Jack; Ayyanar, Raja

    2003-01-01

    A hybrid, soft-switching, DC-DC converter has been developed with superior soft switching characteristics, high efficiency, and low electro-magnetic interference. This hybrid topology is comprised of an uncontrolled bridge operating at full pulse-width, and a controlled section operating as a conventional phase modulated converter. The unique topology is able to maintain zero voltage switching down to no load operating conditions. A breadboard prototype was developed and tested to demonstrate the benefits of the topology. Improvements were then made to reduce the size of passive components and increase efficiency in preparation for packaging. A packaged prototype was then designed and built, and several innovative packaging techniques are presented. Performance test data is presented that reveals deficiencies in the design of the power transformer. A simple redesign of the transformer windings eliminated the deficiency. Future plans to improve the converter and packaging design are presented along with several conclusions.

  6. Influence of the inverter characteristics on the iron losses in PWM inverter fed induction motors

    SciTech Connect

    Boglietti, A.; Ferraris, P.; Lazzari, M.; Pastorelli, M.

    1995-12-31

    In this paper the authors deal with the effects of the inverter characteristics on the iron losses increment in induction motors fed by PWM controlled converters. Laboratory tests based on no-load input power measurement were carried out and in order to avoid the influence of mechanical losses and rotor copper losses, difficult to be measured or computed, a special test bench with an unconventional test device was employed. In particular the influence of the following inverter parameters are considered: modulation index; modulation waveform; switching frequency. Complete experimental results are presented and discussed.

  7. 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.

  8. 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

  9. High performance control of a three-level IGBT inverter fed AC drive

    SciTech Connect

    Zhang, J.

    1995-12-31

    Three-level PWM inverters have been increasingly employed in industry and traction applications where high power and efficiency energy conversions are required. This paper presents a high performance control of a cage induction motor drive fed by a 100 Hp three-level IGBT inverter operating at a low switching frequency. A practical math model of the drive control system is established to aid in the control design to improve the system stability, dynamic performance and robustness over a wide speed range. The modeling and the simulation in Matlab/Simulink facilitate the self-tuning of the regulators in the multi-loop systems. The field oriented control and three-level space-vector modulation together with the drive protection and diagnostics are implemented in software based on a DSP TMS320C31. Experimental results based on the IGBT inverter prototype are given to verify the design and performance. Test results in motor common-mode voltage reduction and inverter neutral-point potential control re also briefly presented.

  10. Extreme ultraviolet detection using AlGaN-on-Si inverted Schottky photodiodes

    SciTech Connect

    Malinowski, Pawel E.; Mertens, Robert; Van Hoof, Chris; Duboz, Jean-Yves; Semond, Fabrice; Frayssinet, Eric; Verhoeve, Peter; Giordanengo, Boris; BenMoussa, Ali

    2011-04-04

    We report on the fabrication of aluminum gallium nitride (AlGaN) Schottky diodes for extreme ultraviolet (EUV) detection. AlGaN layers were grown on silicon wafers by molecular beam epitaxy with the conventional and inverted Schottky structure, where the undoped, active layer was grown before or after the n-doped layer, respectively. Different current mechanisms were observed in the two structures. The inverted Schottky diode was designed for the optimized backside sensitivity in the hybrid imagers. A cut-off wavelength of 280 nm was observed with three orders of magnitude intrinsic rejection ratio of the visible radiation. Furthermore, the inverted structure was characterized using a EUV source based on helium discharge and an open electrode design was used to improve the sensitivity. The characteristic He I and He II emission lines were observed at the wavelengths of 58.4 nm and 30.4 nm, respectively, proving the feasibility of using the inverted layer stack for EUV detection.

  11. Semi-transparent inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Schmidt, H.; Winkler, T.; Tilgner, M.; Flügge, H.; Schmale, S.; Bülow, T.; Meyer, J.; Johannes, H.-H.; Riedl, T.; Kowalsky, W.

    2009-08-01

    We will present efficient semi-transparent bulk-heterojunction [regioregular of poly(3-hexylthiophene): (6,6)-phenyl C61 butyric acid methyl ester] solar cells with an inverted device architecture. Highly transparent ZnO and TiO2 films prepared by Atomic Layer Deposition are used as cathode interlayers on top of ITO. The topanode consists of a RF-sputtered ITO layer. To avoid damage due to the plasma deposition of this layer, a sputtering buffer layer of MoO3 is used as protection. This concept allows for devices with a transmissivity higher than 60 % for wavelengths 650 nm. The thickness of the MoO3 buffer has been varied in order to study its effect on the electrical properties of the solar cell and its ability to prevent possible damage to the organic active layers upon ITO deposition. Without this buffer or for thin buffers it has been found that device performance is very poor concerning the leakage current, the fill factor, the short circuit current and the power conversion efficiencies. As a reference inverted solar cells with a metal electrode (Al) instead of the ITO-top contact are used. The variation between the PCE of top versus conventional illumination of the semi-transparent cells was also examined and will be interpreted in view of the results of the optical simulation of the dielectric device stack with and without reflection top electrode. Power conversion efficiencies of 2-3 % for the opaque inverted solar cells and 1.5-2.5 % for the semi-transparent devices were obtained under an AM1.5G illumination.

  12. Alpha detection in pipes using an inverting membrane scintillator

    SciTech Connect

    Kendrick, D.T.; Cremer, C.D.; Lowry, W.

    1995-10-01

    Characterization of surface alpha emitting contamination inside enclosed spaces such as piping systems presents an interesting radiological measurement challenge. Detection of these alpha particles from the exterior of the pipe is impossible since the alpha particles are completely absorbed by the pipe wall. Traditional survey techniques, using hand-held instruments, simply can not be used effectively inside pipes. Science and Engineering Associates, Inc. is currently developing an enhancement to its Pipe Explorer{trademark} system that will address this challenge. The Pipe Explorer{trademark} uses a unique sensor deployment method where an inverted tubular membrane is propagated through complex pipe runs via air pressure. The inversion process causes the membrane to fold out against the pipe wall, such that no part of the membrane drags along the pipe wall. This deployment methodology has been successfully demonstrated at several DOE sites to transport specially designed beta and gamma, scintillation detectors into pipes ranging in length up to 250 ft.

  13. Suspended-Patch Antenna With Inverted, EM-Coupled Feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2004-01-01

    An improved suspended-patch antenna has been designed to operate at a frequency of about 23 GHz with linear polarization and to be one of four identical antennas in a rectangular array. The antenna includes a parasitic patch on top of a suspended dielectric superstrate, an active patch on top of a suspended dielectric substrate, a microstrip on the bottom of the dielectric substrate, and a ground plane. The microstrip, the ground plane, the airgap between them, and the dielectric substrate together constitute a transmission line that has an impedance of 50 Ohm and is electromagnetically (EM) coupled to the active patch. The parasitic patch is, in turn, excited by the active patch. The microstrip feed is characterized as inverted because the microstrip is on the bottom of the substrate, whereas microstrips are usually placed on the tops of dielectric substrates

  14. An Approach to Suppressing Both Shaft Voltage and Leakage Current in an AC Motor Driven by a Voltage-Source PWM Inverter

    NASA Astrophysics Data System (ADS)

    Doumoto, Takafumi; Akagi, Hirofumi

    This paper proposes a practical approach to suppressing both shaft voltage and leakage current in an ac motor driven by a voltage-source PWM inverter. This approach is characterized by using a neutral line of the ac motor. A common-mode inductor is connected between the inverter and the motor. Moreover, a resistor and a capacitor are connected in series between the motor neutral point and the inverter negative dc bus. This unique circuit configuration makes the common-mode inductor effective in reducing the common-mode voltage appearing at the motor terminals. As a result, both shaft voltage and ground current are significantly suppressed with low cost. Over-voltages at the end of a cable can be suppressed by a normal-mode inductor and a resistor which are connected in parallel. The validity and effectiveness of the new approach are verified by experimental results from a 5-kVA laboratory system.

  15. Three-Phase Modular Cascaded H-Bridge Multilevel Inverter with Individual MPPT for Grid-Connected Photovoltaic Systems

    SciTech Connect

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

    2013-01-01

    A three-phase modular cascaded H-bridge multilevel inverter for a grid-connected photovoltaic (PV) system is presented in this paper. To maximize the solar energy extraction of each PV string, an individual maximum power point tracking (MPPT) control scheme is applied, which allows the independent control of each dc-link voltage. PV mismatches may introduce unbalanced power supplied to the three-phase system. To solve this issue, a control scheme with modulation compensation is proposed. The three-phase modular cascaded multilevel inverter prototype has been built. Each H-bridge is connected to a 185 W solar panel. Simulation and experimental results are presented to validate the proposed ideas.

  16. Volunteer Losing Balance Wearing Inverted Glasses

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Brad McLain for the Space Biology Museum Network puts a volunteer back on balance as he tries to adjust to a world inverted by a special pair of glasses. This helps illustrate how dependent the human vestibular system is on visual cues. A volunteer is The activity was part of the Space Research and You education event held by NASA's Office of Biological and Physical Research on June 25, 2002, in Arlington, VA, to highlight the research that will be conducted on STS-107.

  17. Control of particle flux and energy on substrate in an inverted cylindrical magnetron for plasma PVD

    NASA Astrophysics Data System (ADS)

    Todoran, A.; Mantel, M.; Bés, A.; Vachey, C.; Lacoste, A.

    2014-12-01

    Inverted cylindrical magnetrons (ICMs) are often used in dc, pulsed dc or mid-frequency ac mode for coating complex objects with thin films deposited by plasma PVD. Since in such a configuration the substrate is inherently surrounded by the target and hence by the plasma, the energy flux of the impinging particles represents the main contribution to the substrate heating. This can readily constitute a limiting factor in the deposition process, especially when it is not possible to cool and bias the substrate. This work concerns a dc-driven ICM configuration subjected to several constraints: not only is the substrate surface area small by comparison to the cathode surface area, but its imposed potential is the ground one, thus itself constituting the anode surface of the considered setup. Several important substrate heating factors are highlighted and, in order to reduce the most prominent of them, a means to raise the plasma potential is proposed. This is achieved by positively polarizing two additional electrodes with respect to the ground. This additional surface generates a redistribution of the current and consequently regulates the electron flux on the substrate. The results are shown as a function of bias applied on the auxiliary electrodes and discussed in terms of the impact on the substrate heating.

  18. Novel multilevel inverter carrier-based PWM method

    SciTech Connect

    Tolbert, L.M.; Habetler, T.G.

    1999-10-01

    The advent of the transformerless multilevel inverter topology has brought forth various pulsewidth modulation (PWM) schemes as a means to control the switching of the active devices in each of the multiple voltage levels in the inverter. An analysis of how existing multilevel carrier-based PWM affects switch utilization for the different levels of a diode-clamped inverter is conducted. Two novel carrier-based multilevel PWM schemes are presented which help to optimize or balance the switch utilization in multilevel inverters. A 10-kW prototype six-level diode-clamped inverter has been built and controlled with the novel PWM strategies proposed in this paper to act as a voltage-source inverter for a motor drive.

  19. Soft Switching SEPP High Frequency Inverter for Induction Heating

    NASA Astrophysics Data System (ADS)

    Ogiwara, Hiroyuki; Nakaoka, Mutsuo

    This paper presents a novel circuit topology to attain soft switching operation of a high frequency inverter. Its output power is regulated over a wide range using a PWM control technique by connecting an auxiliary resonant circuit to the conventional single ended push pull (SEPP) high frequency inverter for induction heating. All switching devices in the proposed inverter are operated soft switching mode. This paper describes its circuit constitution and obtained experimental results from a practical point of view.

  20. Apollo 14 inverted pigeonites - Possible samples of lunar plutonic rocks.

    NASA Technical Reports Server (NTRS)

    Papike, J. J.; Bence, A. E.

    1972-01-01

    Analysis of 'inverted pigeonites' found in Apollo 14 samples 14082 and 14083 (a polymict breccia, the 'white rock') by a combination of optical, electron probe, and single-crystal X-ray diffraction techniques. These 'inverted pigeonites' are regarded as samples of plutonic rocks that have been blasted out of the Imbrium Basin. It is also concluded that lunar pigeonites will invert to orthopyroxenes, given sufficiently slow cooling histories even in very anhydrous environments.

  1. Top-gate hybrid complementary inverters using pentacene and amorphous InGaZnO thin-film transistors with high operational stability

    NASA Astrophysics Data System (ADS)

    Kim, J. B.; Fuentes-Hernandez, C.; Hwang, D. K.; Potscavage, W. J.; Kippelen, B.

    2012-03-01

    We report on the operational stability of low-voltage hybrid organic-inorganic complementary inverters with a top-gate bottom source-drain geometry. The inverters are comprised of p-channel pentacene and n-channel amorphous InGaZnO thin-film transistors (TFTs) with bi-layer gate dielectrics formed from an amorphous layer of a fluoropolymer (CYTOP) and a high-k layer of Al2O3. The p- and n- channel TFTs show saturation mobility values of 0.1 ± 0.01 and 5.0 ± 0.5 cm2/Vs, respectively. The individual transistors show high electrical stability with less than 6% drain-to-source current variations after 1 h direct current (DC) bias stress. Complementary inverters yield hysteresis-free voltage transfer characteristics for forward and reverse input biases with static DC gain values larger than 45 V/V at 8 V before and after being subjected to different conditions of electrical stress. Small and reversible variations of the switching threshold voltage of the inverters during these stress tests are compatible with the observed stability of the individual TFTs.

  2. Inverted Face Processing in Body Dysmorphic Disorder

    PubMed Central

    Feusner, Jamie D.; Moller, Hayley; Altstein, Lily; Sugar, Catherine; Bookheimer, Susan; Yoon, Joanne; Hembacher, Emily

    2010-01-01

    Individuals with body dysmorphic disorder (BDD) are preoccupied with perceived defects in appearance. Preliminary evidence suggests abnormalities in global and local visual information processing. The objective of this study was to compare global and local processing in BDD subjects and healthy controls by testing the face inversion effect, in which inverted (upside-down) faces are recognized more slowly and less accurately relative to upright faces. Eighteen medication-free subjects with BDD and 17 matched, healthy controls performed a recognition task with sets of upright and inverted faces on a computer screen that were either presented for short duration (500 msec) or long duration (5000 msec). Response time and accuracy rates were analyzed using linear and logistic mixed effects models, respectively. Results indicated that the inversion effect for response time was smaller in BDD subjects than controls during the long duration stimuli, but was not significantly different during the short duration stimuli. Inversion effect on accuracy rates did not differ significantly between groups during either of the two durations. Lesser inversion effect in BDD subjects may be due to greater detail-oriented and piecemeal processing for long duration stimuli. Similar results between groups for short duration stimuli suggest that they may be normally engaging configural and holistic processing for brief presentations. Abnormal visual information processing in BDD may contribute to distorted perception of appearance; this may not be limited to their own faces, but to others’ faces as well. PMID:20434170

  3. Inverting dedevelopment: geometric singularity theory in embryology

    NASA Astrophysics Data System (ADS)

    Bookstein, Fred L.; Smith, Bradley R.

    2000-10-01

    The diffeomorphism model so useful in the biomathematics of normal morphological variability and disease is inappropriate for applications in embryogenesis, where whole coordinate patches are created out of single points. For this application we need a suitable algebra for the creation of something from nothing in a carefully organized geometry: a formalism for parameterizing discrete nondifferentiabilities of invertible functions on Rk, k $GTR 1. One easy way to begin is via the inverse of the development map - call it the dedevelopment map, the deformation backwards in time. Extrapolated, this map will inevitably have singularities at which its derivative is zero. When the dedevelopment map is inverted to face forward in time, the singularities become appropriately isolated infinities of derivative. We have recently introduced growth visualizations via extrapolations to the isolated singularities at which only one directional derivative is zero. Maps inverse to these create new coordinate patches directionally rather than radically. The most generic singularity that suits this purpose is the crease f(x,y) equals (x,x2y+y3), which has already been applied in morphometrics for the description of focal morphogenetic phenomena. We apply it to embryogenesis in the form of its analytic inverse, and demonstrate its power using a priceless new data set of mouse embryos imaged in 3D by micro-MR with voxels smaller than 100micrometers 3.

  4. Series resonance inverter with triggered vacuum gaps

    NASA Astrophysics Data System (ADS)

    Damstra, Geert C.; Zhang, X.

    1994-05-01

    Series resonance inverters based on semi-conductor switching elements are well-known and have a wide range of application, mainly for lower voltages. For high voltage application many switching elements have to be put in series to obtain sufficient blocking voltage. Voltage grinding and multiple gate control elements are needed. There is much experience with the triggered vacuum gaps as high voltage/high current single shot elements, for example in reignition circuits for synthetic circuit breaker tests. These elements have a blocking voltage of 50 - 100 kV and are triggerable by a light fiber control device. A prototype inverter has been developed that generates 0.1 Hz, 30 kV AC voltages with a flat top for tests on cables and capacitors of many micro farads fed from a low voltage supply of about 600 V. Only two TVG elements are needed to switch the resonant circuit alternatively on the positive or negative supply. The resonant circuit itself consists of the capacitance of the testobject and a high quality inductor that determines the frequency and the peak current of the voltage reversing process.

  5. Fabrication and Evaluation of a High Performance SiC Inverter for Wireless Power Transfer Applications

    SciTech Connect

    Onar, Omer C; Campbell, Steven L; Ning, Puqi; Miller, John M; Liang, Zhenxian

    2013-01-01

    In this study, a high power density SiC high efficiency wireless power transfer converter system via inductive coupling has been designed and developed. The detailed power module design, cooling system design and power stage development are presented. The successful operation of rated power converter system demonstrates the feasible wireless charging plan. One of the most important part of this study is the wind bandgap devices packaged at the Oak Ridge National Laboratory (ORNL) using the in-house packaging technologies by employing the bare SiC dies acquired from CREE, which are rated at 50 A / 1200 V each. These packaged devices are also inhouse tested and characterized using ORNL s Device Characterization Facility. The successful operation of the proposed inverter is experimentally verified and the efficiency and operational characteristics of the inverter are also revealed.

  6. 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.

  7. 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.

  8. 75 FR 36298 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-8-31, DC-8-32, DC-8-33, DC-8-41...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-25

    ...-09-04, Amendment 39-15484 (73 FR 21523, April 22, 2008), for all Model DC-8-31, DC-8-32, DC-8-33, DC... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3... removing Amendment 39-15484 (73 FR 21523, April 22, 2008) and adding the following new AD:...

  9. 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.

  10. Light-weight DC to very high voltage DC converter

    DOEpatents

    Druce, R.L.; Kirbie, H.C.; Newton, M.A.

    1998-06-30

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

  11. Light-weight DC to very high voltage DC converter

    DOEpatents

    Druce, Robert L.; Kirbie, Hugh C.; Newton, Mark A.

    1998-01-01

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current.

  12. Digital state feedback control of a three phase sinusoidal PWM inverter

    SciTech Connect

    Matin, Md.A.; Divsalar, D.

    1994-12-31

    This paper proposes a method of three phase voltage control sinusoidal PWM (Pulse Width Modulation) inverter. The state equation of the inverter main circuit has been derived and transformed to the d-q frame. Afterwards, an algorithm of dead-beat control has been developed by considering only the load current as disturbing variable. The advantage of dead-beat control is that it can control very fast within short time (sampling period) comparing to other methods. The main objective of the controller design is to get the sinusoidal voltage at inverter`s output with low harmonic distortions. To compensate the calculation delay and to realize physically, a 3d order prediction method has been adopted. A new switching technique has been developed. This switching technique can reduce unnecessary switching so that switching loss can be minimized. Finally, simulations has been done under a typical load condition (rectifier with capacitor load) and harmonic analysis has also been done. Throughout all simulations, very good results have been found where total harmonic distortions (THD) is less than 5%.

  13. Fun D.C. Jobs for Physicists

    SciTech Connect

    Clark Cully

    2009-09-30

    Physicists make valuable contributions in a wide variety of careers, including those in Washington. Many national challenges, including energy, innovation, and security, create a demand for technically-competent individuals across government. Clark will discuss some of the many programs in D.C. designed to attract the best and brightest minds, from grad-students to professors, from short-term assignments to whole new careers. These are great opportunities to use your expertise and enrich your knowledge of the broader scientific enterprise, all while serving society.

  14. Evaluation of battery converters based on 4. 8-MW fuel cell demonstrator inverter. Final report. [Contains brief glossary

    SciTech Connect

    Not Available

    1980-10-01

    Electrical power conditioning is a critical element in the development of advanced electrochemical energy storage systems. This program evaluates the use of existing self-commutated converter technology (as developed by the Power Systems Division of United Technologies for the 4.8-MW Fuel Cell Demonstrator) with modification for use in battery energy storage systems. The program consists of three parts: evaluation of the cost and performance of a self-commutated converter modified to maintain production commonality between battery and fuel cell power conditioners, demonstration of the principal characteristics required for the battery application in MW-scale hardware, and investigation of the technical requirements of operation isolated from the utility system. A power-conditioning system consisting of a self-commutated converter augmented with a phase-controlled rectifier was selected and a preliminary design, prepared. A principal factor in this selection was production commonality with the fuel cell inverter system. Additional types of augmentation, and the use of a self-commutated converter system without augmentation, were also considered. A survey of advanced battery manufacturers was used to establish the dc interface characteristics. The principal characteristics of self-commutated converter operation required for battery application were demonstrated with the aid of an available 0.5-MW development system. A survey of five REA and municipal utilities and three A and E firms was conducted to determine technical requirements for operation in a mode isolated from the utility. Definitive requirements for this application were not established because of the limited scope of this study. 63 figures, 37 tables.

  15. DC CICC retrofit magnet

    SciTech Connect

    Myatt, R.L.; Marston, P.G.

    1992-10-30

    The coil system presented here for the MHD retrofit magnet incorporates many features of the latest in superconducting magnet technology and finite element modeling to create an efficient and viable design concept. At the core of the design is the niobium titanium (NbTi) superconducting Cable-in-Conduit Conductor (CICC). Engineered to create moderately high magnetic fields (up to 8 T) with essentially no power loss, this specific CICC design provides good load carrying capacity, operating margin from a perturbation such as a local heat input, and coil protection in the event of a quench transient. The CICC is wound on a mandrel into long, tapered, saddle shaped single conductor thickness pancakes. By defining the appropriate number of conductor turns in each pancake, the saddle coils can be stacked to form a semi-elliptical winding pack cross section. Extruded aluminum filler blocks are fitted into the steps, at the edge of the pancake and present a smooth surface to the supporting structure. The semi-elliptical conductor array is supported by an identically shaped strap at all locations except where the end turns sweep over the MHD channel. The strap resists the electromagnetic forces tending to separate the coils on each side of the channel. Low friction surfaces are placed between conductor pancakes, and between the inside skin of the support straps and the outside surface of the conductor winding pack. This allows relative movement between pancakes, and between the strap and coil, thereby reducing shear stresses and coulombic friction heating which would otherwise tend to crack insulation, load joints, and initiate a quench in the superconducting cable.

  16. Improved power control using optimal adjustable coefficients for three-phase photovoltaic inverter under unbalanced grid voltage.

    PubMed

    Wang, Qianggang; Zhou, Niancheng; Lou, Xiaoxuan; Chen, Xu

    2014-01-01

    Unbalanced grid faults will lead to several drawbacks in the output power quality of photovoltaic generation (PV) converters, such as power fluctuation, current amplitude swell, and a large quantity of harmonics. The aim of this paper is to propose a flexible AC current generation method by selecting coefficients to overcome these problems in an optimal way. Three coefficients are brought in to tune the output current reference within the required limits of the power quality (the current harmonic distortion, the AC current peak, the power fluctuation, and the DC voltage fluctuation). Through the optimization algorithm, the coefficients can be determined aiming to generate the minimum integrated amplitudes of the active and reactive power references with the constraints of the inverter current and DC voltage fluctuation. Dead-beat controller is utilized to track the optimal current reference in a short period. The method has been verified in PSCAD/EMTDC software. PMID:25243215

  17. Improvement in the performance of inverted organic solar cell using electric field assisted spray deposited ZnO layer

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Neha; Swami, Sanjay Kumar; Dutta, Viresh

    2015-06-01

    ZnO film was deposited using spray technique. The application of electric field (applying a DC voltage = 700V to the nozzle) during spray deposition provide compact nanostructured film of ZnO as compared to agglomerated ZnO film deposited using spray process. The ZnO film deposited after applying DC voltage during spray process showed good crystallinity as well as transmittance in the visible range. Use of this crystalline, compact layer of ZnO in inverted organic solar cell (ITO/ZnO/P3HT: PCBM/Ag) provide improved efficiency of 2.8% with JSC of 14.0 mA/cm2, VOC of 0.55V and FF of 36%. Thus the process remove the need of any post deposition treatment to improve the film quality as well as solar cell performance.

  18. Improved Power Control Using Optimal Adjustable Coefficients for Three-Phase Photovoltaic Inverter under Unbalanced Grid Voltage

    PubMed Central

    Wang, Qianggang; Zhou, Niancheng; Lou, Xiaoxuan; Chen, Xu

    2014-01-01

    Unbalanced grid faults will lead to several drawbacks in the output power quality of photovoltaic generation (PV) converters, such as power fluctuation, current amplitude swell, and a large quantity of harmonics. The aim of this paper is to propose a flexible AC current generation method by selecting coefficients to overcome these problems in an optimal way. Three coefficients are brought in to tune the output current reference within the required limits of the power quality (the current harmonic distortion, the AC current peak, the power fluctuation, and the DC voltage fluctuation). Through the optimization algorithm, the coefficients can be determined aiming to generate the minimum integrated amplitudes of the active and reactive power references with the constraints of the inverter current and DC voltage fluctuation. Dead-beat controller is utilized to track the optimal current reference in a short period. The method has been verified in PSCAD/EMTDC software. PMID:25243215

  19. Bifurcation Analysis and Dynamic Behaviour of an Inverted Pendulum with Bounded Control

    NASA Astrophysics Data System (ADS)

    Nikolov, Svetoslav; Nedev, Valentin

    2016-03-01

    This paper presents an investigation on the behaviour of con- ventional inverted pendulum with an inertia disk in its free extreme. The system is actuated by means of torques applied to the disk by a DC mo- tor, mounted on the pendulum's arm. Thus, the system is underactuated since the pendulum can rotate freely around its pivot point. The dynam- ical model is given with three ordinary nonlinear differential equations. Using Poincare-Andronov-Hopf's theory, we find a new analytical formula for the first Lyapunov's value at the boundary of stability. It enables one to study in detail the bifurcation behaviour of the above dynamic system. We check the validity of our analytical results on the first Lyapunov's value by numerical simulations. Hence, we find some new results.

  20. View of the upper part of the Inverted Siphon showing ...

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

    View of the upper part of the Inverted Siphon showing sandbox at the top of the slope before dropping into the Hot Water (or White) Canyon. Looking northeast - Childs-Irving Hydroelectric Project, Irving System, Inverted Siphon, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ