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S K Changchien - One of the best experts on this subject based on the ideXlab platform.

  • interleaved four phase buck based current source with center tapped energy recovery scheme for electrical discharge machining
    IEEE Transactions on Power Electronics, 2009
    Co-Authors: S K Changchien
    Abstract:

    This paper presents the interleaved four-phase buck-based current source in continuous conduction mode with proposed isolated energy-recovery scheme for electrical discharge machining (EDM). EDM requires a pulse current with high slew rate in the output current of the current source. The interleaving technique allows the output slew rate of the buck-based current source to be improved due to the existence of the paralleled inductors at the start of discharge. The proposed isolated energy-recovery scheme provides a major path for the inductor to release its stored energy, thus avoiding high voltage stress in the output terminal when the gap reverts to the high-impedance state. The energy stored in the inductor is recycled to the Input Capacitor and can be reused for machining. The experimental results validate that the output current slew rate is high and that the energy is recovered when the gap is in the high-impedance state.

  • interleaved four phase buck based current source with center tapped energy recovery scheme for electrical discharge machining
    Applied Power Electronics Conference, 2008
    Co-Authors: S K Changchien
    Abstract:

    This paper proposes a center-tapped energy-recovery scheme used in the interleaved four-phase buck-based current source in continuous conduction mode (CCM) for electrical discharge machining (EDM). A pulse machining current with high slew rate is required for the EDM. Using the interleaving technique, the output current slew rate of the buck-based current source can be improved because of the paralleled inductors at the start of discharge. The proposed center-tapped energy-recovery scheme provides a major path for the inductor to release its stored energy to avoid high voltage stress in the output terminal when the gap is in the high-impedance state. The energy stored in the inductor is recovered to the Input Capacitor, and can be reused for machining. The experimental results are provided as the verification of the high output current slew rate and the energy recovery when the gap is in high-impedance state.

Yoon Sang-jin - One of the best experts on this subject based on the ideXlab platform.

  • Reduction of Input voltage/current ripples of boost half-bridge DC-DC converter for photovoltaic micro-inverter
    PERGAMON-ELSEVIER SCIENCE LTD, 2019
    Co-Authors: Lee Hyeon-seok, Kang Bongkoo, Kim Wook-sung, Yoon Sang-jin
    Abstract:

    This paper describes a boost half-bridge DC-DC converter for photovoltaic system that reduces the Input voltage and current ripples by using a 1:1 transformer and an auxiliary Capacitor. The 1:1 transformer replaces the boost inductor in a previous boost half-bridge converter. The auxiliary Capacitor is connected serially to the secondary coil of the 1:1 transformer, and resonates with the leakage inductance of the 1:1 transformer. The Input voltage and current ripples are reduced by setting the switching frequency equal to the resonance frequency between the auxiliary Capacitor and the leakage inductance, and by coupling the resonance current to the primary coil of the 1:1 transformer. The proposed converter had Input voltage ripple less than 0.2 V-p.p, Input current ripple less than 0.81 A(p.p), 5, and power-conversion efficiency higher than 94.5% when the converter was operated at Input voltage of 30-50 V, output voltage of 400 V, output power of 30-300 W, and switching frequency of 46 kHz. These experimental results show that the proposed converter is well suited for photovoltaic micro-inverter applications that require a small Input Capacitor, low Input voltage, high Input current, high output voltage, and high power-conversion efficiency.1

  • Reduction of Input voltage/current ripples of boost half-bridge DC-DC converter for photovoltaic micro-inverter
    'Elsevier BV', 2019
    Co-Authors: Lee Hyeon-seok, Kang Bongkoo, Kim Wook-sung, Yoon Sang-jin
    Abstract:

    This paper describes a boost half-bridge DC-DC converter for photovoltaic system that reduces the Input voltage and current ripples by using a 1:1 transformer and an auxiliary Capacitor. The 1:1 transformer replaces the boost inductor in a previous boost half-bridge converter. The auxiliary Capacitor is connected serially to the secondary coil of the 1:1 transformer, and resonates with the leakage inductance of the 1:1 transformer. The Input voltage and current ripples are reduced by setting the switching frequency equal to the resonance frequency between the auxiliary Capacitor and the leakage inductance, and by coupling the resonance current to the primary coil of the 1:1 transformer. The proposed converter had Input voltage ripple less than 0.2 V-p.p, Input current ripple less than 0.81 A(p.p), 5, and power-conversion efficiency higher than 94.5% when the converter was operated at Input voltage of 30-50 V, output voltage of 400 V, output power of 30-300 W, and switching frequency of 46 kHz. These experimental results show that the proposed converter is well suited for photovoltaic micro-inverter applications that require a small Input Capacitor, low Input voltage, high Input current, high output voltage, and high power-conversion efficiency.11Nsciescopu

Ting Qian - One of the best experts on this subject based on the ideXlab platform.

  • Submodule integrated boost DC-DC converters with no external Input Capacitor or Input inductor for low power photovoltaic applications
    2016 IEEE Energy Conversion Congress and Exposition (ECCE), 2016
    Co-Authors: Jen-hung Huang, Brad Lehman, Ting Qian
    Abstract:

    This paper proposes to utilize the internal solar cell diffusion capacitance and internal solar module wire parasitic inductances to replace the Input Capacitor and filter inductor in boost derived DC-DC converters for energy harvesting applications. High switching frequency (MHz) hard switched and resonant boost converters are proposed. Analysis, simulation and experimental prototypes are presented. A specific proof-of-concept application is especially tested for foldable photovoltaic (PV) panels, which are known for their high internal wire inductance. The experimental converters successfully boost solar module voltage without adding any external Input capacitance or filter inductor.

Yoon-geol Choi - One of the best experts on this subject based on the ideXlab platform.

  • Power Factor Improvement of Flyback PFC Converter Operating at the Light Load
    2019 IEEE Applied Power Electronics Conference and Exposition (APEC), 2019
    Co-Authors: Oscar Andrés Montes, Yoon-geol Choi
    Abstract:

    We propose a duty-ratio feed-forward controller for flyback power factor correction (PFC) converters operating in discontinuous conduction mode (DCM). For PFC applications, the power factor (PF) of the Input current must be high under most load conditions. To improve PF of the flyback converter even under light load, we propose a compensation method for Input Capacitor current. The proposed controller significantly improves the displacement factor as well as the distortion factor, and therefore fly-back PFC converter can achieve the high power quality. Meanwhile, the output voltage of the PFC converter is well regulated. The derivation of the proposed method is presented and effectiveness of the proposed method is demonstrated in experiments with a 100-W rated power prototype.

Cheinyao Liao - One of the best experts on this subject based on the ideXlab platform.

  • three port flyback type single phase micro inverter with active power decoupling circuit
    Energy Conversion Congress and Exposition, 2011
    Co-Authors: Yaowming Chen, Cheinyao Liao
    Abstract:

    The objective of this paper is to propose a novel three-port flyback-type single-phase micro-inverter with active power decoupling circuit (APDC). The proposed micro-inverter can improve the performance of the maximum power point tracking (MPPT) while reducing the size of the Input Capacitor. The electrolytic Capacitor would be replaced by the film ones and the reliability of the micro-inverter can be improved significantly. The operation principle of the proposed micro-inverter will be explained. The computer simulation results of a 200W micro-inverter would be presented to verify the performance of the proposed micro-inverter.