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Seungki Sul - One of the best experts on this subject based on the ideXlab platform.

  • pulsewidth Modulation Method of matrix converter for reducing output current ripple
    IEEE Transactions on Power Electronics, 2010
    Co-Authors: Sungmin Kim, Youngdoo Yoon, Seungki Sul
    Abstract:

    A matrix converter interfaces with three-phase ac voltage source, which creates three different virtual dc-link voltages. In this paper, a new pulsewidth Modulation (PWM) Method for the matrix converter is proposed to generally use these three virtual dc-link voltages. By using the two higher line-to-line voltages as the virtual dc-link voltages, the proposed Method can create the identical switching sequences to those created by the conventional space vector PWM (SVPWM) Method. Moreover, the proposed Method is able to select the appropriate virtual dc-link voltage, according to the PWM purpose and/or load condition. In this paper, the virtual dc-link voltages adjacent to the output voltage reference are introduced to reduce output-current switching ripples. The feasibility of the proposed PWM Method was verified by a computer simulation and experimental results. The output voltage and current waveforms produced by using the proposed Method can be equal or better than those created using the conventional SVPWM Method. Moreover, a new switching sequence that reduces output-current switching ripple can be easily adopted within the proposed PWM Method. The harmonic characteristics of output current created using the proposed Method are markedly improved over those using the conventional PWM Method.

  • carrier based Modulation technique for matrix converter
    IEEE Transactions on Power Electronics, 2006
    Co-Authors: Youngdoo Yoon, Seungki Sul
    Abstract:

    This paper presents a carrier-based Modulation Method for a matrix converter. By using the offset voltage and changing the slope of carrier, it is possible to synthesize the sinusoidal input currents with the unity power factor and desired output voltages. The proposed Method is equivalent to the so called space vector pulsewidth Modulation Method. The proposed Method uses a new point of view to understand the matrix converter Modulation Method such as the voltage source inverter (VSI) Modulation Method. Using the proposed Method, this paper presents the two-phase/three-phase Modulation Method and dynamic/steady-state overModulation Method for the matrix converter. These Methods are well developed in the study of a VSI. By the proposed steady-state overModulation Method, it is possible to synthesize the fundamental component of output voltage to be equal to that of input voltage at the cost of some distortion of input current. The feasibility of the proposed Modulation Method has been verified by a computer simulation and experimental results. These results show that the proposed carrier-based Modulation Method can be implemented easily without any tables. It can be used for the application where a higher voltage transfer ratio is essential

  • a carrier based pwm Method for three phase four leg voltage source converters
    IEEE Transactions on Power Electronics, 2004
    Co-Authors: Janghwan Kim, Seungki Sul
    Abstract:

    In this paper a voltage Modulation Method based on a triangular carrier wave for the three-phase four-leg voltage source converter is described. The four-leg converter can produce three output voltages independently with one additional leg. The proposed Modulation Method for the four-leg converter can be implemented with a single carrier by a simple but useful "offset voltage" concept. The Method is equivalent to the so called three-dimensional space vector PWM Method, but its implementation is much easier. The maximum magnitude of the balanced three-phase voltage and the maximum magnitude of zero sequence voltage, which can be synthesized simultaneously, are derived. The feasibility of the proposed Modulation technique is verified by computer simulation and experimental results. These results show that a proposed carrier-based pulsewidth Modulation (PWM) technique can be easily implemented without conventional computational burden.

Jian Feng Liu - One of the best experts on this subject based on the ideXlab platform.

  • A carrier Modulation Method for minimizing the dc link capacitor current ripple of the HEV DC-DC converter and inverter systems
    Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC, 2011
    Co-Authors: Xi Lu, Wei Qian, Fang Z. Peng, Dong Cao, Jian Feng Liu
    Abstract:

    Minimization of the dc capacitor is an essential step towards developing and manufacturing compact low-cost hybrid electric vehicle (HEV) converter/inverter systems for high temperature operation, long life and high reliability. Previously, most papers have been focused on the AC-DC-AC pulse-width Modulation (PWM) converters with relatively complicated close-loop control Methods, while few papers have analyzed the DC-DC-AC PWM converters that also commonly exist in HEV systems. The so-called DC-DC-AC PWM converter consists of a bidirectional dc-dc converter and an inverter cascaded together. This paper proposes a carrier Modulation Method for the previously mentioned dc-dc converter, which connects the battery or any energy storage system to the dc link, in order to match the converter output current with the inverter input current so as to minimize the current ripple going through the dc link capacitor. Compared with the conventional triangle carrier, the proposed carrier is able to shift the converter output current pulses left and right, so they match with the inverter input current, and finally minimize the current ripple flowing through the dc link capacitor at unity power factor by a simple and easy implementation. Simulation and experimental results are provided to validate the effectiveness of the proposed Method.

Xiaodong Liu - One of the best experts on this subject based on the ideXlab platform.

  • an average current Modulation Method for single stage led drivers with high power factor and zero low frequency current ripple
    IEEE Journal of Emerging and Selected Topics in Power Electronics, 2015
    Co-Authors: Brian J White, Hongliang Wang, Yanfei Liu, Xiaodong Liu
    Abstract:

    Conventional single-stage light-emitting diode (LED) drivers with a high power factor (PF) contain a significant LED current ripple at twice the ac line frequency, and would require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a dc voltage to ensure a limited low-frequency LED current ripple. This paper proposes an average current Modulation Method that is designed to operate in conjunction with single-stage PF correction (PFC) circuits that contain significant ac voltage ripple, while maintaining zero low-frequency current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic-type capacitors and prolonging the life of the LED driver. The average current Modulation circuit requires a single low-voltage MOSFET, a current sense resistor, and a simple control circuit. By requiring no additional magnetic components, the cost of the current Modulation circuit is very low and has minimal impact on the efficiency of the overall LED driver. Two experimental prototypes, an 8.75-W system with a buck–boost PFC converter and a 25-W system with a flyback PFC converter, have been built to verify the capability and excellent performance of the proposed driving technique.

Fang Z. Peng - One of the best experts on this subject based on the ideXlab platform.

  • theoretical analysis of dc link capacitor current ripple reduction in the hev dc dc converter and inverter system using a carrier Modulation Method
    European Conference on Cognitive Ergonomics, 2012
    Co-Authors: Fang Z. Peng
    Abstract:

    This paper presents theoretical analysis of the dc link capacitor current ripple reduction in the HEV dc-dc converter and inverter system by using a proposed carrier Modulation Method. This carrier Modulation Method introduces a modified triangle carrier, with a switching frequency that is twice as much as the inverter's, for the dc-dc converter to synchronize this dc-dc converter output current with the SPWM inverter input current. Resulting from this synchronization, the current ripple flowing into the dc link capacitor is greatly reduced by 50%, compared to the unsynchronized traditional triangle carrier Method, whose switching frequency is the same as the inverter's. Experimental results are obtained from a 30 kW boost converter and inverter prototype. Theoretical equations are derived to demonstrate the effectiveness for all situations, considering different load power factors and dc-dc converter duty cycles.

  • A carrier Modulation Method for minimizing the dc link capacitor current ripple of the HEV DC-DC converter and inverter systems
    Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC, 2011
    Co-Authors: Xi Lu, Wei Qian, Fang Z. Peng, Dong Cao, Jian Feng Liu
    Abstract:

    Minimization of the dc capacitor is an essential step towards developing and manufacturing compact low-cost hybrid electric vehicle (HEV) converter/inverter systems for high temperature operation, long life and high reliability. Previously, most papers have been focused on the AC-DC-AC pulse-width Modulation (PWM) converters with relatively complicated close-loop control Methods, while few papers have analyzed the DC-DC-AC PWM converters that also commonly exist in HEV systems. The so-called DC-DC-AC PWM converter consists of a bidirectional dc-dc converter and an inverter cascaded together. This paper proposes a carrier Modulation Method for the previously mentioned dc-dc converter, which connects the battery or any energy storage system to the dc link, in order to match the converter output current with the inverter input current so as to minimize the current ripple going through the dc link capacitor. Compared with the conventional triangle carrier, the proposed carrier is able to shift the converter output current pulses left and right, so they match with the inverter input current, and finally minimize the current ripple flowing through the dc link capacitor at unity power factor by a simple and easy implementation. Simulation and experimental results are provided to validate the effectiveness of the proposed Method.

Brian J White - One of the best experts on this subject based on the ideXlab platform.

  • an average current Modulation Method for single stage led drivers with high power factor and zero low frequency current ripple
    European Conference on Cognitive Ergonomics, 2015
    Co-Authors: Brian J White, Hongliang Wang, Yanfei Liu
    Abstract:

    Conventional single-stage AC-DC LED drivers with a high power factor contain significant LED current ripple at twice the AC line frequency, and require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a DC voltage to ensure a limited low frequency current ripple. This paper proposes an average current Modulation Method that is capable of driving LEDs from a voltage that contains significant AC ripple, while maintaining zero low frequency current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic type capacitors, and prolonging the life of the LED driver. The average current Modulation circuit requires a single low voltage MOSFET, a current sense resistor and a simple control circuit. By requiring no additional magnetic components, the cost of the average current Modulation circuit is very low, and has minimal impact on the efficiency of the overall LED driver. A 25 W experimental prototype with a Flyback PFC converter has been built to verify the capability and excellent performance of the proposed driving technique.

  • an average current Modulation Method for single stage led drivers with high power factor and zero low frequency current ripple
    IEEE Journal of Emerging and Selected Topics in Power Electronics, 2015
    Co-Authors: Brian J White, Hongliang Wang, Yanfei Liu, Xiaodong Liu
    Abstract:

    Conventional single-stage light-emitting diode (LED) drivers with a high power factor (PF) contain a significant LED current ripple at twice the ac line frequency, and would require large energy storage capacitors to limit the effect on LED light. Conventional designs and novel control techniques aim to power LED loads with a dc voltage to ensure a limited low-frequency LED current ripple. This paper proposes an average current Modulation Method that is designed to operate in conjunction with single-stage PF correction (PFC) circuits that contain significant ac voltage ripple, while maintaining zero low-frequency current ripple. This allows the energy storage capacitance of the PFC stage to be reduced, avoiding the need for electrolytic-type capacitors and prolonging the life of the LED driver. The average current Modulation circuit requires a single low-voltage MOSFET, a current sense resistor, and a simple control circuit. By requiring no additional magnetic components, the cost of the current Modulation circuit is very low and has minimal impact on the efficiency of the overall LED driver. Two experimental prototypes, an 8.75-W system with a buck–boost PFC converter and a 25-W system with a flyback PFC converter, have been built to verify the capability and excellent performance of the proposed driving technique.