一种混合开关电感和开关电容的高增益DC/DC变换器

针对传统Z源DC/DC变换器存在的输入电流不连续、输出电压增益不够高和功率器件电压应力较高等不足,利用开关电感和开关电容技术,提出了一种混合开关高增益DC/DC变换器。该变换器主电路中只用到1个储能电容,结构简单,与现有典型的高增益阻抗源DC/DC变换器相比,所提出的混合开关电感和开关电容的DC/DC变换器可以实现更高的输出电压增益,同时电容和开关器件的电压应力较低。详细分析了所提变换器的工作原理,通过在实验室中所建立的输入电压16～40 V、输出电压26～107 V和输出功率7～114 W的原型验证了其性能。     

单开关DC/DC变换器的一种软开关实现策略

该文提出了一种适用于Buck、Boost、Buck-boost、Flyback等各种单开关DC／DC拓扑的软开关实现策略，即同步整流加上电感电流反向的策略。根据两个开关管实现软开关的条件不同，提出了强管和弱管的概念，给出了满足软开关条件的设计方法。一个24V输入，40V／2．5A输出，开关频率为200KHz的同步Boost变换器样机，进一步验证了上述软开关实现策略的正确性，其满载效率达到了96．9％。     

移相控制双Boost型DC-DC变换器

本文提出一种移相控制双Boost型DC-DC变换器,该变换器具有以下特点:控制简单可靠,有现成的移相控制芯片可用;有源和无源器件都能实现软开关,不增加开关的电流电压应力;由于它的输入电感电流和输出电压纹波频率都为开关频率的两倍,达到了倍频的效果。所以,与传统的Boost型DC-DC变换器相比,在输入输出条件相同的情况下,输入电感和输出电容都可以减小。本文详细分析了这种变换器的工作原理,在理论分析的基础上进行了仿真研究,仿真结果证明了理论分析的正确性。     

基于多模式控制的储能用双向Buck-Boost DC/DC变换器

由于各种分布式能源的大量接入，电网需要加入储能单元以平抑潮流的波动。储能系统中，为了在宽输入、输出电压范围的情况下实现高效双向电能转换，探讨一种基于多模式控制的双向Buck-Boost DC/DC变换器。当输入电压显著高于输出电压时，变换器工作在Buck模式，采用谷值电流控制。当输入电压显著低于输出电压时，变换器工作在Boost模式，采用峰值电流控制。当输入电压接近输出电压时，变换器工作在Buck-Boost组合模式，采用移相控制来实现平滑过渡。为了实现高精度的输出和快速的动态响应，控制环路采用二型补偿器。通过Buck模式和Boost模式小部分重叠工作的方式，消除了传统Buck-Boost变换器在模式切换时存在的断续现象。制作的1 kW实验样机具有97.5%的峰值效率以及Buck模式与Boost模式平滑切换的特点。     

基于倍压单元耦合电感高增益DC/DC变换器

提出一种基于倍压单元的新型DC/DC高增益变换器。在传统Boost变换器的基础上引入倍压单元,提高变换器电压增益,并把2个储能电感进行磁集成,减小变换器体积和电感电流纹波。分析了该变换器的工作原理以及工作模态,推导了输出电压增益公式、各二极管和开关管的电压应力以及电感电流纹波。与传统Boost变换器相比,电压增益提高了（3+D）倍,开关管应力电压减小明显,电感电流纹波减小一半。通过仿真和实验,验证了理论分析的正确性。     

DC/DC变换器软开关电路的仿真研究

介绍了DC/DC变换器的种类,讨论了软开关的工作原理和零电压开关及零电流开关的实现方式。并对BUCK变换器的零电流准谐振电路和Boost变换器的零电压准谐电流进行仿真分析。     

平均电流模式控制软开关移相全桥DC/DC变换器

本文研制了一种24V输入,300V输出的DC DC变换器,该变换器采用了带辅助谐振网络的全桥变换器拓扑结构,仿真和实验结果表明,变换器中的超前桥臂和滞后桥臂在较宽的负载条件下都可实现零电压开关(ZVS)条件,降低了变换器的开关损耗。另外,也可以明显降低变压器副边的占空比丢失,提高了变换器的效率和输出电压的调节范围。本文还采用了平均电流模式的控制方式,实现了输出电压和输出电流的双闭环控制,所设计的移相全桥DC DC变换器具有较好的动态性能和控制精度。     

单电感E2类软开关DC/DC变换器

介绍了一种只用一个电感的单端E^2类软开关DC／DC变换器。IGBT（MOSFET或BJT）的零电压开关和整流二极管的零电流开关能够降低逆变器和整流器中的损耗。提出了一种分析和设计方案,确定了最佳工作状态下的性能参数。如电流和电压波形,最大集电极电流和最大集-射极电压以及功率输出能力,并对IGBT和整流二极管的功耗进行了估算。实验证明,在频率f=-100kHz,输出功率Po=2kW的情况下变换器的整体效率可达到91％。     

基于变频控制的串联谐振DC/DC变换器的研究

串联谐振DC/DC变换器具有电路结构简单、在全输入和全负载范围内可实现开关管的ZVS、功率转换效率高等优点,是目前开关电源研究的热点之一。本文分析了基于变频控制的串联谐振DC/DC变换器的工作原理,阐明了变换器在三种不同开关频率下的工作特性,定量地给出了不同工作状态下变换器的输入电压、输出电压、开关频率以及谐振电感等参数之间的关系式。在一台1.5KW原理样机上的实验结果表明,该变换器变换效率最高可达96.3%,所有开关管实现ZVS,不同工作状态时变换器输入输出电压等参数关系与理论分析一致。     

新型二次型高增益DC/DC变换器及特性研究

新能源发电系统普遍存在输出电压较低的问题,一定程度上限制了新能源的发展,因此研究一款高升压比的DC/DC变换器具有重要意义。为提高DC/DC Boost变换器的电压增益,在传统二次型变换器的基础上引入开关电容和开关电感技术,提出一种新型二次型高增益Boost变换器。详细阐述了新型变换器的拓扑结构和工作原理;获得了变换器的电压增益以及各个器件的电压应力,并与其他的高增益DC/DC变换器进行对比分析;最后采用SiC器件制作了一台实验样机,验证了理论分析的正确性。结果表明,提出的变换器具有高升压比、低器件应力等优点,实现了电压增益与器件应力的良好平衡,适用于新能源系统。     

Hybrid DC–DC converter with high efficiency,wide ZVS range,and less output inductance

In this paper, a new soft switching direct current (DC)–DC converter with low circulating current, wide zero voltage switching range, and reduced output inductor is presented for electric vehicle or plug‐in hybrid electric vehicle battery charger application. The proposed high‐frequency link DC–DC converter includes two resonant circuits and one full‐bridge phase‐shift pulse‐width modulation circuit with shared power switches in leading and lagging legs. Series resonant converters are operated at fixed switching frequency to extend the zero voltage switching range of power switches. Passive snubber circuit using one clamp capacitor and two rectifier diodes at the secondary side is adopted to reduce the primary current of full‐bridge converter to zero during the freewheeling interval. Hence, the circulating current on the primary side is eliminated in the proposed converter. In the same time, the voltage across the output inductor is also decreased so that the output inductance can be reduced compared with the output inductance in conventional full‐bridge converter. Finally, experiments are presented for a 1.33‐kW prototype circuit converting 380 V input to an output voltage of 300–420 V/3.5 A for battery charger applications. Copyright © 2015 John Wiley & Sons, Ltd.     

新型对称控制方式三相三电平直流变换器

半桥三电平变换器具有开关管电压应力低、易于实现软开关等优点,适用于高输入电压场合。但随着输出功率的提高,开关管的电流应力也随之增加。为降低开关管的电流应力,提出一种新型三相三电平直流变换器,与已有三相三电平变换器相比,该变换器开关管数量大幅减少。采用对称控制方式,所有开关管的电压应力均为输入电压的一半;采用三相电路结构,可降低开关管的电流应力,同时可有效提高输入输出电流脉动频率,进而减小滤波器。制作一台600 V输入、48 V/20 A输出的原理样机,实验结果验证了理论分析的有效性和正确性。     

Analysis and implementation of a high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter

A high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter with ripple‐free input current is presented. In the presented converter, the ripple‐free boost cell provides ripple‐free input current and zero‐voltage switching of power switches. The resonant flyback cell provides zero‐voltage switching of power switches and zero‐current switching of the output diode. Also, it has a simple output stage. The proposed converter achieves high efficiency because of the reduction of the switching losses of the power switches and the output diode. Detailed analysis and design of the proposed converter are carried out. A prototype of the proposed converter is developed and its experimental results are presented for validation. Copyright © 2011 John Wiley & Sons, Ltd.     

面向家庭直流微电网的多端口变换器研究

为减少家庭直流微电网中变换器的数量,本文提出了一种新型多端口直流变换器及其控制策略。该变换器具备4个端口,原边通过将双向Buck/Boost电路和移相全桥变换器的两个桥臂开关管进行复用而得到两个输入端口,副边与同步Buck变换器相结合构成高、低压两个输出端口,并通过选择和比较各端口的控制量实现多端口变换器控制策略的切换。该变换器能够实现多电压等级输入/输出及其端口电压的恒定控制、能量双向流动以及控制策略切换等功能,相较于其他多端口变换器,具有结构简单、功率密度高等优点。最后,本文通过Matlab/Simunlink软件搭建仿真模型,并进行详细的实验分析,结果验证了理论分析的正确性和有效性。     

ZVS DC/DC converter with series half‐bridge legs for high voltage application

This paper presents a new DC/DC converter with series half‐bridge legs for high voltage application. Two half‐bridge legs connected in series and two split capacitors are used in the proposed circuit to limit the voltage stress of each active switch at one‐half of input voltage. Thus, active switches with low voltage stress can be used at high DC bus application. In the proposed converter, two circuit modules are operated with an interleaved pulse‐width modulation scheme to reduce the input and output ripple currents and to achieve load current sharing. In each circuit module, two resonant tanks are operated with phase‐shift one‐half of switching cycle such that the frequency of the input current is twice the frequency of the resonant inductor current. Based on the resonant behavior, all MOSFETs are turned on at zero voltage switching with the wide ranges of input voltage and load conditions. The rectifier diodes can be turned off at zero current switching if the switching frequency is less than the series resonant frequency. Thus, the switching losses on power semiconductors are reduced. The proposed converter can be applied for high input voltage applications such as three‐phase 380‐V utility system. Finally, experiments based on a laboratory prototype with 960‐W rated power are provided to demonstrate the performance of proposed converter. Copyright © 2011 John Wiley & Sons, Ltd.     

A new parallel ZVS converter with less power switches and low current stress components

A new direct current (DC)/DC converter with parallel circuits is presented for medium voltage and power applications. There are five pulse‐width modulation circuits in the proposed converter to reduce current stress at low voltage side for high output current applications. These five circuits share the same power switches in order to reduce switch counts. To reduce the converter size, conduction loss, and voltage stress of power semiconductors, the series connections of power metal‐oxide‐semiconductor field‐effect transistor (MOSFET) with high switching frequency instead of insulated gate bipolar transistor (IGBT) with low switching frequency are adopted. Thus, the voltage stress of MOSFETs is clamped at half of input voltage. The switched capacitor circuit is adopted to balance input split capacitor voltages. Asymmetric pulse‐width modulation scheme is adopted to generate the necessary switching signals of MOSFETs and regulate output voltage. Based on the resonant behavior at the transition interval of power switches, all MOSFETs are turned on under zero voltage switching from 50% load to 100% load. The circuit configuration, operation principle, converter performance, and design example are discussed in detail. Finally, experimental verifications with a 1.92 kW prototype are provided to verify the performance of the proposed converter. Copyright © 2015 John Wiley & Sons, Ltd.     

A half‐bridge resonant DC/DC converter with satisfactory soft‐switching characteristics

In this paper, a half‐bridge resonant DC/DC converter with constant output voltage is proposed, which possesses good soft‐switching characteristics. At rated operating point, the switches can operate almost without switching‐on and off losses. Further, at whole working range, both zero‐voltage‐switching mode of switches and zero‐current‐switching mode of diodes are maintained. Thus, the converter can achieve a high efficiency. Experimental results verify the low switching losses and high efficiency characteristics based on a 200 W prototype. System efficiency is as high as 96% and always above 90% when output power changes from 100% to 20%. Copyright © 2016 John Wiley & Sons, Ltd.     

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.     

一种新型临界模式控制的变频软开关全桥DC/DC变流器

储能电感位于原边的全桥DC/DC变流器(full bridgeconverter with primary side energy storage inductor,FB-PESI),采用传统的固定频率、移向控制(phase-shift,PS)方式时主要工作于断续导通模式(discontinuous conductionmode,DCM),不适合应用于宽范围电压输入的场合。为克服PSFB-PESI变流器的这一缺点,提出一种新型的采用变频(variable frequency,VF)控制策略的FB-PESI DC/DC变流器(VFFB-PESI)。该VFFB-PESI变流器不仅保留了PSFB-PESI变流器宽范围软开关、高效率、高功率密度的优点,还可始终工作于临界导通模式(critical continuous operation mode,CrCM),从而在宽输入电压范围内均可获得较高的变换效率。同时给出了针对该VFFB-PESI变流器的损耗分析方法和优化设计流程。通过制作的300 W、200~400 V输入、12 V输出样机实验,验证了理论分析的正确性。     

一种电源-电容串联型直流变换器

提出了一种电源-电容串联型直流变换器,这种拓扑结构可以同时为两路直流电源升压,并且有效降低了半导体器件的电压与电流应力。与双路Boost型直流变换器相比,该电源-电容串联型直流变换器在不增加功率器件数量的前提下,显著降低了半导体器件的电压与电流应力,适用于分布式光伏并网逆变器的直流变换级。主要涉及该直流变换器的运行方式、电压与电流应力分析、效率对比,并通过实验验证了该直流变换器的可行性。