The Experts below are selected from a list of 21840 Experts worldwide ranked by ideXlab platform

Benjamin J. Blalock - One of the best experts on this subject based on the ideXlab platform.

  • a di dt feedback based active gate driver for smart switching and fast overcurrent protection of igbt modules
    IEEE Transactions on Power Electronics, 2014
    Co-Authors: Zhiqiang Wang, Fei Wang, Xiaojie Shi, Leon M Tolbert, Benjamin J. Blalock
    Abstract:

    This paper presents an active gate driver (AGD) for IGBT modules to improve their overall performance under normal condition as well as fault condition. Specifically, during normal switching transients, a di/dt feedback controlled current source and current sink is introduced together with a push-pull buffer for dynamic gate current control. Compared to a conventional gate drive strategy, the proposed one has the capability of reducing the switching loss, delay time, and Miller plateau duration during turn-on and turn-off transient without sacrificing current and voltage stress. Under overcurrent condition, it provides a fast protection function for IGBT modules based on the evaluation of fault current level through the di/dt feedback signal. Moreover, the AGD features flexible protection modes, which overcomes the interruption of Converter operation in the event of momentary short circuits. A Step-down Converter is built to evaluate the performance of the proposed driving schemes under various conditions, considering variation of turn-on/off gate resistance, current levels, and short-circuit fault types. Experimental results and detailed analysis are presented to verify the feasibility of the proposed approach.

  • Design and Performance Evaluation of Overcurrent Protection Schemes for Silicon Carbide (SiC) Power MOSFETs
    Ieee Transactions on Industrial Electronics, 2014
    Co-Authors: Z Q Wang, X. J. Shi, Yuncan Xue, Laren M. Tolbert, Fei Wang, Benjamin J. Blalock
    Abstract:

    Overcurrent protection of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) remains a challenge due to lack of practical knowledge. This paper presents three overcurrent protection methods to improve the reliability and overall cost of SiC MOSFET-based Converters. First, a solid-state circuit breaker (SSCB) composed primarily by a Si IGBT and a commercial gate driver IC is connected in series with the dc bus to detect and clear overcurrent faults. Second, the desaturation technique using a sensing diode to detect the drain-source voltage under overcurrent faults is implemented as well. Third, a novel active overcurrent protection scheme through dynamic evaluation of fault current level is proposed. The design considerations and potential issues of the protection methods are described and analyzed in detail. A phase-leg configuration-based Step-down Converter is built to evaluate the performance of the protection schemes under various conditions, considering variation of fault type, decoupling capacitance, protection circuit parameters, etc. Finally, a comparison is made in terms of fault response time, temperature-dependent characteristics, and applications to help designers select a proper protection method.

  • design and performance evaluation of overcurrent protection schemes for silicon carbide sic power mosfets
    Energy Conversion Congress and Exposition, 2013
    Co-Authors: Zhiqiang Wang, Laren M. Tolbert, Benjamin J. Blalock, Fred Wang
    Abstract:

    Overcurrent protection of silicon carbide (SiC) MOSFETs remains a challenge due to lack of practical knowledge. This paper presents two overcurrent protection methods to improve the reliability and overall cost of the SiC MOSFET based Converter. First, a solid state circuit breaker (SSCB) composed primarily by a Si IGBT and a commercial gate driver IC is connected in series with the DC bus to detect and clear overcurrent faults. Second, the desaturation technique using a sensing diode to detect the drain-source voltage under overcurrent faults is implemented as well. The design considerations and potential issues of the protection methods are described and analyzed in detail. A phase-leg configuration based Step-down Converter is built to evaluate the performance of the proposed protection schemes under various conditions, considering variation of fault type, decoupling capacitance, protection circuit parameters, etc. Finally, a comparison is made in terms of fault response time, temperature dependent characteristics, and applications to help designers select a proper protection method.

George A Lesieutre - One of the best experts on this subject based on the ideXlab platform.

  • damping as a result of piezoelectric energy harvesting
    Journal of Sound and Vibration, 2004
    Co-Authors: George A Lesieutre, Geffrey Ottman, Heath Hofmann
    Abstract:

    Abstract Systems that harvest or scavenge energy from their environments are of considerable interest for use in remote power supplies. A class of such systems exploits the motion or deformation associated with vibration, converting the mechanical energy to electrical, and storing it for later use; some of these systems use piezoelectric materials for the direct conversion of strain energy to electrical energy. The removal of mechanical energy from a vibrating structure necessarily results in damping. This research addresses the damping associated with a piezoelectric energy harvesting system that consists of a full-bridge rectifier, a filter capacitor, a switching DC–DC Step-down Converter, and a battery. Under conditions of harmonic forcing, the effective modal loss factor depends on: (1) the electromechanical coupling coefficient of the piezoelectric system; and (2) the ratio of the rectifier output voltage during operation to its maximum open-circuit value. When the DC–DC Converter is maximizing power flow to the battery, this voltage ratio is very nearly 1/2, and the loss factor depends only on the coupling coefficient. Experiments on a base-driven piezoelectric cantilever, having a system coupling coefficient of 26%, yielded an effective loss factor for the fundamental vibration mode of 2.2%, in excellent agreement with theory.

  • Optimized piezoelectric energy harvesting circuit using Step-down Converter in discontinuous conduction mode
    IEEE Transactions on Power Electronics, 2003
    Co-Authors: Geffrey K. Ottman, Heath Hofmann, George A Lesieutre
    Abstract:

    An optimized method of harvesting vibrational energy with a piezoelectric element using a Step-down DC-DC Converter is presented. In this configuration, the Converter regulates the power flow from the piezoelectric element to the desired electronic load. Analysis of the Converter in discontinuous current conduction mode results in an expression for the duty cycle-power relationship. Using parameters of the mechanical system, the piezoelectric element, and the Converter; the "optimal" duty cycle can be determined where the harvested power is maximized for the level of mechanical excitation. It is shown that, as the magnitude of the mechanical excitation increases, the optimal duty cycle becomes essentially constant, greatly simplifying the control of the Step-down Converter. The expression is validated with experimental data showing that the optimal duty cycle can be accurately determined and maximum energy harvesting attained. A circuit is proposed which implements this relationship, and experimental results show that the Converter increases the harvested power by approximately 325%.

  • optimized piezoelectric energy harvesting circuit using step down Converter in discontinuous conduction mode
    Power Electronics Specialists Conference, 2002
    Co-Authors: Geffrey K. Ottman, Heath Hofmann, George A Lesieutre
    Abstract:

    An optimized method of harvesting vibrational energy with a piezoelectric element using a Step-down DC-DC Converter is presented. In this configuration, the Converter regulates the power flow from the piezoelectric element to the desired electronic load. Analysis of the Converter in discontinuous current conduction mode results in an expression for the duty cycle-power relationship. Using parameters of the mechanical system, the piezoelectric element, and the Converter an optimal duty cycle can be determined where the harvested power is maximized for a given frequency of mechanical excitation. It is shown that, as the magnitude of the excitation increases, the optimal duty cycle becomes essentially constant, greatly simplifying the control of the Step-down Converter. The expression is validated with experimental data showing that the optimal duty cycle can be accurately determined and maximum energy harvesting attained. A circuit is proposed which implements this relationship, and experimental results show that the Converter increases the harvested power by approximately 325%.

Zhiqiang Wang - One of the best experts on this subject based on the ideXlab platform.

  • a di dt feedback based active gate driver for smart switching and fast overcurrent protection of igbt modules
    IEEE Transactions on Power Electronics, 2014
    Co-Authors: Zhiqiang Wang, Fei Wang, Xiaojie Shi, Leon M Tolbert, Benjamin J. Blalock
    Abstract:

    This paper presents an active gate driver (AGD) for IGBT modules to improve their overall performance under normal condition as well as fault condition. Specifically, during normal switching transients, a di/dt feedback controlled current source and current sink is introduced together with a push-pull buffer for dynamic gate current control. Compared to a conventional gate drive strategy, the proposed one has the capability of reducing the switching loss, delay time, and Miller plateau duration during turn-on and turn-off transient without sacrificing current and voltage stress. Under overcurrent condition, it provides a fast protection function for IGBT modules based on the evaluation of fault current level through the di/dt feedback signal. Moreover, the AGD features flexible protection modes, which overcomes the interruption of Converter operation in the event of momentary short circuits. A Step-down Converter is built to evaluate the performance of the proposed driving schemes under various conditions, considering variation of turn-on/off gate resistance, current levels, and short-circuit fault types. Experimental results and detailed analysis are presented to verify the feasibility of the proposed approach.

  • design and performance evaluation of overcurrent protection schemes for silicon carbide sic power mosfets
    Energy Conversion Congress and Exposition, 2013
    Co-Authors: Zhiqiang Wang, Laren M. Tolbert, Benjamin J. Blalock, Fred Wang
    Abstract:

    Overcurrent protection of silicon carbide (SiC) MOSFETs remains a challenge due to lack of practical knowledge. This paper presents two overcurrent protection methods to improve the reliability and overall cost of the SiC MOSFET based Converter. First, a solid state circuit breaker (SSCB) composed primarily by a Si IGBT and a commercial gate driver IC is connected in series with the DC bus to detect and clear overcurrent faults. Second, the desaturation technique using a sensing diode to detect the drain-source voltage under overcurrent faults is implemented as well. The design considerations and potential issues of the protection methods are described and analyzed in detail. A phase-leg configuration based Step-down Converter is built to evaluate the performance of the proposed protection schemes under various conditions, considering variation of fault type, decoupling capacitance, protection circuit parameters, etc. Finally, a comparison is made in terms of fault response time, temperature dependent characteristics, and applications to help designers select a proper protection method.

Fred Wang - One of the best experts on this subject based on the ideXlab platform.

  • design and performance evaluation of overcurrent protection schemes for silicon carbide sic power mosfets
    Energy Conversion Congress and Exposition, 2013
    Co-Authors: Zhiqiang Wang, Laren M. Tolbert, Benjamin J. Blalock, Fred Wang
    Abstract:

    Overcurrent protection of silicon carbide (SiC) MOSFETs remains a challenge due to lack of practical knowledge. This paper presents two overcurrent protection methods to improve the reliability and overall cost of the SiC MOSFET based Converter. First, a solid state circuit breaker (SSCB) composed primarily by a Si IGBT and a commercial gate driver IC is connected in series with the DC bus to detect and clear overcurrent faults. Second, the desaturation technique using a sensing diode to detect the drain-source voltage under overcurrent faults is implemented as well. The design considerations and potential issues of the protection methods are described and analyzed in detail. A phase-leg configuration based Step-down Converter is built to evaluate the performance of the proposed protection schemes under various conditions, considering variation of fault type, decoupling capacitance, protection circuit parameters, etc. Finally, a comparison is made in terms of fault response time, temperature dependent characteristics, and applications to help designers select a proper protection method.

Laren M. Tolbert - One of the best experts on this subject based on the ideXlab platform.

  • Design and Performance Evaluation of Overcurrent Protection Schemes for Silicon Carbide (SiC) Power MOSFETs
    Ieee Transactions on Industrial Electronics, 2014
    Co-Authors: Z Q Wang, X. J. Shi, Yuncan Xue, Laren M. Tolbert, Fei Wang, Benjamin J. Blalock
    Abstract:

    Overcurrent protection of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) remains a challenge due to lack of practical knowledge. This paper presents three overcurrent protection methods to improve the reliability and overall cost of SiC MOSFET-based Converters. First, a solid-state circuit breaker (SSCB) composed primarily by a Si IGBT and a commercial gate driver IC is connected in series with the dc bus to detect and clear overcurrent faults. Second, the desaturation technique using a sensing diode to detect the drain-source voltage under overcurrent faults is implemented as well. Third, a novel active overcurrent protection scheme through dynamic evaluation of fault current level is proposed. The design considerations and potential issues of the protection methods are described and analyzed in detail. A phase-leg configuration-based Step-down Converter is built to evaluate the performance of the protection schemes under various conditions, considering variation of fault type, decoupling capacitance, protection circuit parameters, etc. Finally, a comparison is made in terms of fault response time, temperature-dependent characteristics, and applications to help designers select a proper protection method.

  • design and performance evaluation of overcurrent protection schemes for silicon carbide sic power mosfets
    Energy Conversion Congress and Exposition, 2013
    Co-Authors: Zhiqiang Wang, Laren M. Tolbert, Benjamin J. Blalock, Fred Wang
    Abstract:

    Overcurrent protection of silicon carbide (SiC) MOSFETs remains a challenge due to lack of practical knowledge. This paper presents two overcurrent protection methods to improve the reliability and overall cost of the SiC MOSFET based Converter. First, a solid state circuit breaker (SSCB) composed primarily by a Si IGBT and a commercial gate driver IC is connected in series with the DC bus to detect and clear overcurrent faults. Second, the desaturation technique using a sensing diode to detect the drain-source voltage under overcurrent faults is implemented as well. The design considerations and potential issues of the protection methods are described and analyzed in detail. A phase-leg configuration based Step-down Converter is built to evaluate the performance of the proposed protection schemes under various conditions, considering variation of fault type, decoupling capacitance, protection circuit parameters, etc. Finally, a comparison is made in terms of fault response time, temperature dependent characteristics, and applications to help designers select a proper protection method.