Voltage Unbalance Compensation Method with Zero Voltage Switching for Series Connected Switching Devices

Jun-ichi Itoh,Ryosuke Iso,Hiroki Watanabe 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper proposes a voltage unbalance compensation method of series-connected switching devices for high voltage application such as DC distribution systems. In the series connection, a turn-off voltage unbalance occurs in switching devices due to a parasitic parameter mismatch and a switching timing mismatch among switching devices. In this paper, a capacitor snubber and Zero Voltage Switching (ZVS) operation are utilized to reduce voltage unbalance. In particular, the proposed method reduces the parasitic capacitor (collector-emitter capacitance) mismatch among series-connected devices by a capacitor snubber circuit, whereas the switching losses are effectively reduced by ZVS. As the simulation results, it is confirmed that the collector-emitter voltage unbalance is reduced by 88% by the proposed method in comparison with a snubber-less configuration. Finally, in order to confirm the effectiveness of the proposed method, experiments with a test circuit applied with the proposed method are conducted. According to the experimental results, the voltage unbalance is reduced by 86.0% due to the application of the proposed method.

High Efficiency DC/DC Boost Converters for Medium/High Power Applications

Furqan Zahoor,Swastik Gupta,Vipan Kakkar 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.11

Switching Converters commonly known as DC/DC Converters have gained tremendous popularity due to their use in variety of applications such as hybrid energy systems, hybrid vehicles, satellite applications and portable electronic devices to name a few. The main positives of using high step up converters include improving voltage gain, reduction of voltage stress and current ripple. But these converters seem to have some disadvantages like very high EMI due to reverse recovery of the boost diode and considerable amount of losses which occur due to hard switching of the boost switch. Many variations of the original boost schematic have been suggested to overcome these problems. The Zero Voltage Transition (ZVT) Boost converter and Zero Current Transition (ZCT) Boost converter are such solutions. These soft switching topologies employ an auxiliary resonant circuit which allows the boost switch to turn on and off under zero voltage and zero current conditions respectively thus reducing the switching losses. In addition, these boost converter circuits have major drawback of low power efficiency particularly at light loads due to the negative value of inductor current at light loads. In this research, a novel technique for designing a boost converter is proposed. The proposed converter employs an auxiliary circuit which allows switching of the main switch as well as the auxiliary switch under zero voltage/zero current conditions. In addition, the boost converter automatically senses the zero current across the resonant inductor, thus forcing the convertor to step automatically from Continuous Conduction Mode (CCM) to Discontinuous conduction mode (DCM) when the inductor current tries to go negative. This prevents the inductor current to go negative and hence improve convertor’s power efficiency. A novel boost convertor which steps up 200V input voltage to 400V output is designed in PSIM software with a switching frequency of 100KHz. The simulation results show that the proposed convertor has an efficiency of about 99.3% at nominal output power.

전압 리플을 이용해 영전류 스위칭하는 두 개의 트랜스포머를 가지는 위상천이 풀-브릿지 컨버터

윤현기,한상규,문건우,윤명중 전력전자학회 2006 전력전자학회 논문지 Vol.11 No.1

This paper presents a Zero-Current Switching(ZCS) two-transformer phase-shifted full-bridge(TTFB) converter using voltage ripple. The proposed converter provides Zero-Voltage Switching(ZVS) of leading leg switches and ZCS of lagging leg switches using voltage ripple. Especially, circulating current is reduced by ZCS operation and there are no additional components required for the soft switching of power switches. Furthermore, in case of light load, ZVS operation of lagging leg can be achieved. The operations, analysis and design consideration of proposed converter are presented. To verify the validity of the proposed converter, experimental results for a 410W (205[V], 2[A]) prototype are presented. 본 논문에서는 출력 전압의 리플을 이용하여 지상 레그(lagging leg)의 스위치들의 영전류 스위칭(ZCS)을 수행하는 두 개의 트랜스프머를 가지는 위상천이 풀-브릿지 컨버터를 제안하다. 제안된 컨버터는 진상 레그(leading leg)의 스위치들은 영전압 스위칭(ZVS)을 수행하고, 지상 레그의 스위치들은 출력 전압-더블러(Voltage-Doubler)의 전압 리플차를 이용해 출력 다이오드의 전류 전환(commutation)이 빠르게 이루어지도록 하여서 중부하에는 영전류 스위칭을, 경부하에서는 영전압 스위칭을 가능하게 한다. 또한 출력측의 전압 리플차를 이용하기 때문의 기존의 1차측 부스트 캐패시터를 이용하는 컨버터에 비해 턴비를 이용하여 보다 빠른 전류 전환을 수행할 수 있는 장점을 가진다. 따라서 별도의 추가적인 소자없이 모든 스위치의 소프트스위칭이 가능하도록 하고, 지상 레그의 영전류 스위칭을 통해서 환류구간의 순환전류도 없애줌으로써 높은 효율을 얻을 수 있다. 모드 해석과 실험을 통하여 제안 컨버터의 성능을 검증한다.

Soft switching circuit of high-frequency active neutral point clamped inverter based on SiC/Si hybrid device

Wang, Jianing,Xun, Yuanwu,Liu, Xiaohui,Yu, Shaolin,Jiang, Nan The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.1

Although the silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) is superior to the conventional silicon (Si) insulated gate bipolar transistor in terms of switching performance, the switching losses of SiC devices increase rapidly by hard switching when the switching frequency (f_sw) increase to hundreds of kilohertz (kHz). This paper proposes an auxiliary zero-voltage-transition circuit to realize zero-voltage-switching for all of the high-frequency main switches of the active neutral point clamped (ANPC) inverter based on a SiC/Si hybrid device, and zero-current-switching for all of the auxiliary switches. Through soft switching, the switching losses and anti-parallel diode reverse recovery losses of high-frequency SiC MOSFET switches can be further reduced. First, the circuit topology and the operation principle of the soft switching are detailed followed by the design procedure of the parameters. Then, the efficiencies of hard switching and soft switching ANPC inverters are compared with f_sw changing from 10 to 200 kHz. To further improve the efficiency of the soft-switching inverter, two improved methods are proposed. The two proposed methods are auxiliary switches paralleling the external diode and utilizing synchronous rectification technology. Finally, a 1 kW, up to 200 kHz frequency ANPC inverter has been built to validate the above analysis.

A Novel Three-Phase Voltage-Doubler Soft-Switching Active Filter

Maoh-Chin Jiang,Jing-Jhu Jhan,Kuei Wu-Chang,Huang-Kai Fu 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

A novel three-phase voltage-doubler soft-switching active filter (VDSSAF) comprising four main switches and four auxiliary switches is proposed in this paper. All main switches in the proposed VBSSAF operate at zero-voltage-switching (ZVS) turn on, while the auxiliary switches operate at zero-current-switching (ZCS) turn off. The reduction in the number of switches can also increase the reliability, since the control circuits are thereby reduced to two sets. The proposed VBSSAF can compensate the current harmonics, improve the power factor and balance the unbalanced nonlinear load. Moreover, a critical value of the capacitor voltage magnitude on the DC side and a critical value of the reactor inductance on the AC side for successful harmonic current tracking are also derived for design applications. Some experimental results of the VBSSAF, rated 400 W and operated at 40 ㎑, are provided to demonstrate the performance.

ZVS-FB PWM DC/DC 변환기의 동특성 해석 및 제어기 설계

이득기,윤길문,차영길,김흥근 전력전자학회 1998 전력전자학회 논문지 Vol.3 No.3

본 논문에서는 대용량에 적합한 영전압 스위칭 전브리지 PWM 직류/직류 변한기의 동특성 해석과 제어 루프의 설계에 대해 논하였다. 전압을 제어하기 위한 위상전이제어의 효과와 영전압 스위칭을 위한 변압기의 누설인덕턴스, FET의 적합 커패시턴스의 이용효과를 고려한 소신호 모델을 유도하였다. 이 소신호 모델은 PWM 벅 변환기의 등가모델에 시비율 변조에 대한 두 개의 종속 전원을 추가함으로써 모델링할 수 있다. 소신호 해석 결과를 근거로 하여 2-극점, 1-영점 보상회로를 사용한 전압제어기를 설계하였다. 설계된 제어기의 타당성을 검증하기 위해서 개루프 시스템과 폐루프 시스템의 소신호 해석결과를 비교하였으며, 2kW급 부하실험으로 설계한 전압제어기의 동특성이 우수함을 실험적으로 입증하였다. This paper presents the dynamic analysis and control loop design of a zero voltage switching full bridge (ZVS-FB) PWM DC/DC converter. The small-signal model is derived incorporating the effects of phase shift control and the utilization of transformer leakage inductance and power FET junction capacitance to achieve zero voltage resonant switching. These effects are modeled by introducing additional feedforward and feedback terms for duty cycle modulation. Based on the results of the small-signal analysis, the control loop is designed using a simple two-pole one-zero compensation circuit. To show the validity of the design procedures, the small signal analysis of the closed loop system is carried out and the potential of the zero voltage switching and the superiority of the dynamic characteristics are verified through the experiment with a 2 kW prototype converter.

Zero-Voltage and Zero-Current Switching Interleaved Two-Switch Forward Converter

Chu, Enhui,Bao, Jianqun,Song, Qi,Zhang, Yang,Xie, Haolin,Chen, Zhifang,Zhou, Yue The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

In this paper, a novel zero-voltage and zero-current switching (ZVZCS) interleaved two switch forward converter is proposed. By using a coupled-inductor-type smoothing filter, a snubber capacitor, the parallel capacitance of the leading switches and the transformer parasitic inductance, the proposed converter can realize soft-switching for the main power switches. This converter can effectively reduce the primary circulating current loss by using the coupled inductor and the snubber capacitor. Furthermore, this converter can reduce the reverse recovery loss, parasitic ringing and transient voltage stress in the secondary rectifier diodes caused by the leakage inductors of the transformer and the coupled inductance. The operation principle and steady state characteristics of the converter are analyzed according to the equivalent circuits in different operation modes. The practical effectiveness of the proposed converter was is illustrated by simulation and experimental results via a 500W, 100 kHz prototype using the power MOSFET.

Zero-Voltage and Zero-Current Switching Interleaved Two-Switch Forward Converter

Enhui Chu,Jianqun Bao,Qi Song,Yang Zhang,Haolin Xie,Zhifang Chen,Yue Zhou 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

In this paper, a novel zero-voltage and zero-current switching (ZVZCS) interleaved two switch forward converter is proposed. By using a coupled-inductor-type smoothing filter, a snubber capacitor, the parallel capacitance of the leading switches and the transformer parasitic inductance, the proposed converter can realize soft-switching for the main power switches. This converter can effectively reduce the primary circulating current loss by using the coupled inductor and the snubber capacitor. Furthermore, this converter can reduce the reverse recovery loss, parasitic ringing and transient voltage stress in the secondary rectifier diodes caused by the leakage inductors of the transformer and the coupled inductance. The operation principle and steady state characteristics of the converter are analyzed according to the equivalent circuits in different operation modes. The practical effectiveness of the proposed converter was is illustrated by simulation and experimental results via a 500W, 100 kHz prototype using the power MOSFET.

동기 정류기를 이용한 태양광 모듈용 플라이백 인버터 소프트 스위칭 제어 기법

장진우(Jin-Woo Jang),김영호(Young-Ho Kim),최봉연(Bong-Yeon Choi),정용채(Yong-Chae Jung),원충연(Chung-Yuen Won) 전력전자학회 2013 전력전자학회 논문지 Vol.18 No.4

In this paper, high efficiency control method for flyback inverter with synchronous rectifier(SR) based on photovoltaic AC modules is proposed. In this control method, the operation of SR is classified according to the voltage spike across main switch SP. When the voltage spike across SP is lower than the rating voltage of SP, the operation of active clamp circuit is interrupted for reducing the switching loss of auxiliary switch. In this time, the SR is operated for soft-switching of SP. When the voltage spike across Sp is higher than the rating voltage of SP, the operation of active circuit is activated for reducing the voltage spike. The SR is operated for reducing the conduction loss of secondary output diode. Thus, a switching loss of the main switch can be reduced in low power region, and weighted-efficiency can be improved. A theoretical analysis and the design principle of the proposed method are provided. And validity is confirmed through simulation and experimental results.

Light-Load Efficiency Improvement for Zero-Voltage Switching Boost Integrated Converters

Hyun-Wook Seong,Hyoung-Suk Kim,Gun-Woo Moon,Myung-Joong Youn 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

In general, a zero-voltage switching (ZVS) condition of boost-integrated DC-DC converters is load-dependent and lost at a light load due to an insufficient energy stored in a leakage inductor. To extend a ZVS load range without increasing an external leakage inductor at a light load condition, a frequency modulation (FM) control is proposed. By modulating a switching frequency adaptive to a load current at a desired load range, ZVS can be recovered through an energy stored in a boost inductor so that the switching losses can be significantly reduced. Thus, the conversion efficiency at a light load condition can be improved. A ZVS boost integrated flyback (BIF) converter with a voltage doubler rectifier (VDR) is presented to apply the proposed control method as an example. Experimental results from a digitally implemented prototype are shown to demonstrate the proposed work.