软开关PWM三电平直流变换器

系统地提出PWM三电平直流变换器的一族共9种控制方式,根据一对开关管中两只开关管的关断情况,将这9种控制方式归纳出两类开关切换方式。引入超前管和滞后管的概念,提出它们实现软开关的方式,将软开关PWM三电平直流变换器归纳为零电压开关和零电压/零电流开关两类,并分别指出适合它们的控制策略。提出在零状态电流复位的方法,提出几种零电压/零电流开关三电平直流变换器的电路拓扑。     

软开关PWM DC/DC全桥变换器的实现策略

系统地提出ＰＷＭＤＣ／ＤＣ全桥变换器的两类软开关方式, ＺＶＳ方式和ＺＶＺＣＳ方式。针对这两类方式, 分别提出各自的实现策略。     

Operation analysis of quasi‐resonant,high‐frequency transformer link dc–ac converters applied to phase‐shift PWM control on the secondary side

In recent years, the soft‐switching techniques have attracted attention for their peculiar advantages such as low switching loss, high power density, EMI/RFI noise reduction, and so on. The authors have previously reported on a quasi‐resonant dc–dc converter using new phase‐shift PWM control scheme. By using the proposed control scheme, circulating current is eliminated and ZVS (Zero Voltage Switching) is achieved with small commutating current. As a result, the conduction losses caused by their currents are substantially reduced. In this paper, the authors apply a proposed control scheme to a quasi‐resonant high‐frequency transformer link dc–ac converter. As a result, all switching devises in this dc–ac converter can achieve soft switching with small commutating current irrespective of inverter mode and rectifier mode. Its operating principle and unique features are described as compared with the symmetrical control scheme of dc–ac converter. Operating performance of this dc–ac converter in the steady state is illustrated by means of simulation results. © 1999 Scripta Technica, Electr Eng Jpn, 130(2): 88–98, 2000     

Series resonant ZCS‐PFM DC‐DC power converter with high‐frequency high‐voltage transformer link for high‐power magnetron drive

This paper presents a single lossless inductive snubber‐assisted ZCS‐PFM series resonant DC‐DC power converter with a high‐frequency high‐voltage transformer link for industrial‐use high‐power magnetron drive. The current flowing through the active power switches rises gradually at a turned‐on transient state with the aid of a single lossless snubber inductor, and ZCS turn‐on commutation based on overlapping current can be achieved via the wide range pulse frequency modulation control scheme. The high‐frequency high‐voltage transformer primary side resonant current always becomes continuous operation mode, by electromagnetic loose coupling design of the high‐frequency high‐voltage transformer and the magnetizing inductance of the high‐frequency high‐voltage transformer. As a result, this high‐voltage power converter circuit for the magnetron can achieve a complete zero current soft switching under the condition of broad width gate voltage signals. Furthermore, this high‐voltage DC‐DC power converter circuit can regulate the output power from zero to full over audible frequency range via the two resonant frequency circuit design. Its operating performances are evaluated and discussed on the basis of the power loss analysis simulation and the experimental results from a practical point of view. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 79–87, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20126     

Dynamic model development and control for multiple‐output flyback converters in DCM and CCM

Multiple‐output flyback converters are widely used in switching power supplies due to their low component count and cost‐effective structure. The main problem of this structure is how to balance output voltages in different load conditions. This paper proposes a new approach for single‐input multiple‐output flyback converters operating in DCM and CCM by a small‐signal averaged model. The averaged model is derived by presenting the piecewise‐linear waveform for the inductor currents inside the converter. In DCM, the magnetizing current and currents through the output windings reach zero when the switch is turned off. In CCM, the magnetizing current of the converter is continuous over a switching interval and this possibility exists that only some of the output diodes completely conduct when the switch is off. The proposed model of the converter can be used in a wide range of operations within identical and non‐identical loading conditions. Using a laboratory prototype, several case studies and input‐to‐output transfer functions are considered to verify the proposed model. The controller design is performed for the both CCM and DCM, and then dynamic characteristics of the overall system are evaluated.     

Control schemes for auxiliary switches of three‐phase PWM resonant snubber inverters

Control schemes for auxiliary switches of PWM controlled three‐phase resonant snubber inverters (RSIs) are proposed. The control schemes proposed in this paper are based on a conventional PWM technique. To avoid zero voltage switching lost conditions, the conventional PWM technique is modified in the proposed schemes. The proposed control schemes are so simple that they are suitable for digital control. In this paper, a CPLD (Complex Programmable Logic Device)‐based control IC, which realizes the proposed control schemes, for three‐phase auxiliary RSIs is also proposed and implemented. The IC generates gate signals for the main and auxiliary devices of the three‐phase RSI based on the proposed control schemes. The effectiveness of the proposed control schemes was verified through experiments. As a result, ZVS (Zero Voltage Switching) turn‐on at the main devices was achieved and a smooth sinusoidal output current was obtained by use of the control IC. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(4): 57–67, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20125     

新型ZCT-PWM软斩波调功逆变电源的研究

介绍一种用于逆变电源功率调节的新型零电流转换-脉宽调制(Zero Current Transition-Pulse Width Modulation,简称ZCT-PWM)直流斩波器,与传统Buck-PWM斩波器相比,增加了一个辅助功率开关器件及谐振电感和谐振电容等,克服了传统ZCT-PWM斩波器不能零电流开通(ZCS)和负载续流二极管不能软关断的缺点.该斩波器具有开关损耗低,结构简单,控制方便等优点,适合用于以IGBT为开关器件的高频电源场合.采用高速IGBT开关器件设计了一台5kW/50kHz逆变电源样机.实验结果表明,该样机能高效、可靠地运行在高频大负载变化范围内.     

A ZVS‐ZCS phase shift full bridge DC‐DC converter with secondary‐side control for battery charging applications

The output power requirement of battery charging circuits can vary in a wide range, hence making the use of conventional phase shift full bridge DC‐DC converters infeasible because of poor light load efficiency. In this paper, a new ZVS‐ZCS phase shift full bridge topology with secondary‐side active control has been presented for battery charging applications. The proposed circuit uses 2 extra switches in series with the secondary‐side rectifier diodes, operating with phase shift PWM. With the assistance of transformer's magnetizing inductance, the proposed converter maintains zero voltage switching (ZVS) of the primary‐side switches over the entire load range. The secondary‐side switches regulate the output voltage/current and perform zero current switching (ZCS) independent of the amount of load current. The proposed converter exhibits a significantly better light load efficiency as compared with the conventional phase shift full bridge DC‐DC converter. The performance of the proposed converter has been analyzed on a 1‐kW hardware prototype, and experimental results have been included.     

Series resonant high‐voltage DC–DC converter with reduced component count

This paper proposes a novel zero‐current‐switching series resonant high‐voltage DC–DC converter with reduced component count. The series resonant inverter in the proposed topology has two power switches (insulated‐gate bipolar transistors, IGBTs), two resonant capacitors, and only one high‐voltage transformer (HVT) with center‐tapped primary windings. The power switches are connected in the form of a half‐bridge network. The leakage inductances of the transformer's primary windings together with the resonant capacitors form two series resonant circuits. The series resonant circuits are fed alternately by operating the power switches with interleaved half switching cycle. The secondary winding of the HVT is connected to a bridge rectifier circuit to rectify the secondary voltage. The converter operates in the discontinuous conduction mode (DCM) and its output voltage is regulated by pulse frequency modulation. Therefore, all the power switches turn on and off at the zero‐current switching condition. The main features of the proposed converter are its lower core loss, lower cost, and smaller size compared to previously proposed double series resonant high voltage DC–DC converters. The experimental results of a 130‐W prototype of the proposed converter are presented. The results confirm the excellent operation and performance of the converter. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Soft‐Switching Interleaved PFC Converter with Lossless Snubber

This paper describes a soft‐switching interleaved power factor correction (PFC) converter with a lossless snubber. AC–DC converters require a unity input power factor characteristic with highly efficient operation to prevent the inflow of harmonic current to the power source. The proposed PFC converter improves the input current ripple with interleave control. The converter realizes a high efficiency by the soft‐switching operation of all switching devices without a large auxiliary resonant circuit. This paper introduces the soft‐switching operation of the converter. In order to confirm the validity of the proposed converter, experiments with a prototype of the PFC converter have been performed. The experimental results indicate that the proposed converter can realize the soft‐switching operation of all switching devices, a reduction in the input current ripple, a unity power factor of 98% or more, a sinusoidal input current, and constant output voltage control. The efficiency of the proposed PFC converter with a lossless snubber is higher than that without the lossless snubber. The results presented in this paper confirm the validity of the proposed converter.     

A novel prototype of auxiliary edge resonant bridge leg link snubber‐assisted soft‐switching sine‐wave PWM inverter

This paper proposes a new circuit topology of the three‐phase soft‐switching PWM inverter and PFC converter using IGBT power modules, which has the improved active auxiliary switch and edge resonant bridge leg‐commutation‐link soft‐switching snubber circuit with pulse current regenerative feedback loop as compared with the typical auxiliary resonant pole snubber discussed previously. This three‐phase soft‐switching PWM double converter is more suitable and acceptable for a large‐capacity uninterruptible power supply, PFC converter, utility‐interactive bidirectional converter, and so forth. In this paper, the soft‐switching operation and optimum circuit design of the novel type active auxiliary edge resonant bridge leg commutation link snubber treated here are described for high‐power applications. Both the main active power switches and the auxiliary active power switches achieve soft switching under the principles of ZVS or ZCS in this three‐phase inverter switching. This three‐phase soft‐switching commutation scheme can effectively minimize the switching surge‐related electromagnetic noise and the switching power losses of the power semiconductor devices; IGBTs and modules used here. This three‐phase inverter and rectifier coupled double converter system does not need any sensing circuit and its peripheral logic control circuits to detect the voltage or the current and does not require any unwanted chemical electrolytic capacitor to make the neutral point of the DC power supply voltage source. The performances of this power conditioner are proved on the basis of the experimental and simulation results. Because the power semiconductor switches (IGBT module packages) have a trade‐off relation in the switching fall time and tail current interval characteristics as well as the conductive saturation voltage characteristics, this three‐phase soft‐switching PWM double converter can improve actual efficiency in the output power ranges with a trench gate controlled MOS power semiconductor device which is much improved regarding low saturation voltage. The effectiveness of this is verified from a practical point of view. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(4): 64–76, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20207     

A unidirectional boost chopper with snubber energy regeneration using a coupled inductor

This paper proposes a novel soft‐switching boost chopper with a lossless LC snubber, suitable for improving the efficiency of the electric propulsion system of vehicles. The snubber circuit is beneficial owing to the following features: zero‐current switching turn‐on and zero‐voltage switching turn‐off are achieved regardless of the operating conditions; it requires only one additional switch with smaller current rating compared to the main switch; the additional switch can be controlled by basic arithmetic; and the main switch is free from additional voltage or current stress caused by the soft‐switching operation. Along with theoretical discussions, experimental results are also presented on the circuit behavior and the resulting improvement of the energy conversion efficiency. These results show the usefulness of the chopper for improving the efficiency of electric vehicles. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A low‐loss snubber for reducing motor terminal surge voltage

The development of an advanced Insulated Gate Bipolar Transistor (IGBT) has enabled high‐frequency switching operation and has improved the performance of PWM inverters for motor drive. However, the IGBT's high rate of dv/dt has adverse effects on motor insulation stress. In many motor drive applications, the inverter and motor are separated, requiring long motor feeds. The long cable contributes high‐frequency ringing at the motor terminal and results in high surge voltage which stresses the motor insulation. The inverter output filter and RDC snubber are the conventional method for reducing the surge voltage. In this paper, we propose a new low‐loss snubber to reduce the motor terminal surge voltage. The snubber consists of the series connection of chraging/discharging capacitor and the voltage‐clamped capacitor. At IGBT turn‐off, the snubber starts to operate when the IGBT voltage reaches the voltage‐clamped level. Since dv/dt is decreased by snubber operating, the peak level of the surge voltage can be reduced. Also the snubber operates at the IGBT voltage above the voltage‐clamped level, and the snubber loss is largely reduced compared with the RDC snubber. The proposed snubber enables reduction of the motor terminal surge voltage with low loss. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 150(4): 64–72, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10378     

一种新的直流母线并联谐振零电压过渡三相PWM电压源逆变器

提出了一种新的用于三相电机驱动的直流母线并联谐振零电压过渡电压源逆变器(DC -RailPRZVTVSI’)电路。该电路中所有开关均工作在零电压开关 (ZVS)或零电流开关(ZCS)条件下。该电路对谐振元件和辅助开关的功率要求较低 ,控制简单且不依赖于负载条件 ,过渡过程所需时间可以自由选择。本文给出了该电路详细的理论分析和计算并进行了实验验证 ,结果证实了所提出电路的正确性和有效性。     

Analysis and implementation of a new zero current switching flyback inverter

In this paper, a novel zero current switching (ZCS) flyback inverter in discontinuous conduction mode (DCM) is proposed. In the proposed flyback inverter, the ZCS for the primary switch is achieved by adding a simple auxiliary circuit to the conventional flyback inverter. Also, the auxiliary switch is turned on and turned off at ZCS condition. Therefore, the switching losses of the switches are negligible, which increases the efficiency and allows higher switching frequency and more compact design. The resonant auxiliary cell is activated only in short transition times that makes its conduction losses negligible. Furthermore, the voltage overshoot of the main switch is limited during the turn-off process, which allows utilization of lower voltage metal-oxide semiconductor field-effect transistors (MOSFETs) with low conduction losses and low cost. The detailed operation of the flyback inverter with auxiliary circuit and design considerations are presented. Simulation and experimental results are presented to verify the performance of the proposed inverter.     

Improvement of power conversion efficiency of soft‐switching inverter in range of low output power by adjustable dead time control

The power conversion efficiency of soft‐switching inverters can be improved by using loss‐less snubber commutation; however, the main switches of the inverter fail in zero‐voltage turn‐on when the output current is small. As a solution to this problem, adjustable dead time control in a loss‐less snubber commutation according to the magnitude of output current has been proposed. Adjustable dead time control achieves zero‐voltage turn‐on of the inverter main switches in a loss‐less snubber commutation in the range of low output current; however, waveforms of the output current of the inverter become distorted. In this paper, we propose a scheme for adjustable dead time control with dead time compensation for soft‐switching inverters. The effectiveness of the proposed control scheme is verified by experiments. Experimental results demonstrate that when the proposed control scheme is adopted, the power conversion efficiency in the range of low output power improves up to about 3% and the THD is improved within 3%. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(1): 57–64, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21282     

Newly proposed hybrid resonant commutation bridge‐leg link snubber‐assisted three‐phase ZVZCS‐PWM soft‐switching inverter

This paper presents the newly proposed hybrid resonant commutation bridge‐leg link (HRCB) snubber circuit which can achieve zero voltage and zero current soft‐switching commutation for single‐phase and three‐phase voltage source‐type inverter, along with its unique features and operation principle. The circuit parameter design approach for the HRCB snubber circuit and the determination estimating scheme of the gate pulse timing processing which is more suitable and acceptable for single‐phase and space voltage vector modulated three‐phase voltage source inverter using the HRCB snubber circuit are described in this paper. In particular, the three‐phase voltage source soft‐switching inverter associated with the proposed HRCB circuits are evaluated and discussed from simulation and experimental viewpoints. The practical effectiveness of the HRCB snubber‐assisted three‐phase voltage source soft‐switching inverter using IGBT power modules which is based on the instantaneous space voltage vector modulation is clarified on the output voltage waveform, actual efficiency of electromagnetic noise in comparison with three‐phase voltage source‐type conventional hard‐switching inverter. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(4): 75–84, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20111     

Implementation of an interleaved pulse‐width modulation converter for renewable energy conversion

This paper presents an interleaved soft switching converter to achieve the features of zero voltage switching (ZVS) turn‐on for power switches, zero current switching turn‐off for rectifier diodes at full load, less transformer secondary winding with full‐wave diode rectifier topology, and balance primary currents with series connection of the transformer secondary windings. Two circuit modules are adopted in the proposed circuit, and they are operated with an interleaved pulse‐width modulation. Thus, ripple currents at the input and output sides are reduced. In each module, two ZVS converters using the same switches are operated with interleaved half switching cycle. The secondary windings of transformers are connected in series in order to ensure that the primary side currents are balanced. The full‐wave diode rectifier topology is used on the output side such that the voltage stress of rectifier diodes equals output voltage, rather than being two times the output voltage as in a conventional center‐tapped rectifier topology. Laboratory experiments with a 1000‐W prototype are provided to describe the effectiveness of the proposed converter. Copyright © 2011 John Wiley & Sons, Ltd.     

带无损缓冲的新型三相反激式功率因数校正器的研制

提出了一种新颖的基于反激式变换器的三相功率因数校正器,讨论和分析了该电路的校正原理、关键参数和性能特点,并介绍了两种实用的零电压过渡方案,通过仿真和实验证明了理论分析的正确性.     

一种带有软开关缓冲电路的变流器

为提高变流器的能量转移能力,降低控制电路的复杂性,提出一种适用于升压变流器的新的有源软开关缓冲电路。该电路利用辅助开关来参与能量转移;且升压变流器和缓冲器的开关能以零电压切换(ZV S)关断和零电流切换(ZCS)导通的方式工作。虽然流过升压变流器和缓冲器开关的电流不同,但这些开关在导通的大部分时间里并联运行,因此缓冲器开关参与了从电源到输出的能量转移。两个开关采用相同的控制信号和非隔离的门极驱动电路,控制电路十分简单、可靠。该方法通过一个3.2 kW升压变流器原型的实验结果得到证实。