采用辅助变压器的零电压零电流开关全桥直-直变换器

本文给出了一种新型的零电压零电流开关全桥移相脉宽调制变换器,该变换器采用IGBT为功率开关管,在传统变换器的基础上通过增加辅助变压器的方式提高了变换器的性能,通过增加正激能量恢复缓冲器和辅助电路,使变换器在各种负载以及短路工作状态下都能够保证所有开关管实现零电压零电流开关工作模式。介绍了变换器的工作原理并通过试验得到了较好的结果。     

一种Boost软开关变换器的改进方法

为了减小Boost软开关变换器高频工作状态下开关管的功率损耗,文中提出了一种改进调制策略,传统调制策略下主开关管只能实现零电流开通,通过改变主开关管的开通时刻和辅助开关管的关断时刻可实现主开关管零电压零电流开通,辅助开关管可提前实现零电压零电流关断,提高了电路工作效率。仿真波形中观察到改进调制策略下主开关管实现了零电压零电流开通,辅助开关管提前实现了零电压零电流关断。     

多谐振软开关全桥Boost变换器

提出一种利用多谐振实现开关管软开关的全桥Boost变换器.其将变压器漏感作为谐振电感,利用电感与电容谐振实现桥臂开关管和箝位开关管的软开关.桥臂开关管工作于零电流开通与零电压关断状态.有源箝位电路既可抑制变换器工作时可能出现的振荡电压,又可将箝位电容吸收的能量返还回主电路,且箝位开关管工作于零电压开通与零电流关断状态.最后利用硬件实验验证了其多谐振软开关特性.     

一种采用无源辅助网络的ZVZCS三电平DC-DC变换器

提出一种采用无源辅助网络的零电压零电流开关(ZVZCS)三电平DC-DC;变换器拓扑,其中各开关管电压应力为输入电压的一半,并且能够在宽负载范围内实现各开关管的软开关.副边的无源辅助网络不仅能为滞后管创造零电流关断条件,而且还可抑制变压器副边整流后电压的过冲.本文详细分析了此变换器的工作原理及开关管实现软开关的条件,并通过实验样机验证了理论分析的正确性及此拓扑的可行性.     

基于DSP控制的有源箝位双串联 LC谐振变换器研究

针对传统有源箝位正激变换器,本文提出了一种有源箝位双串联LC谐振变换器,基于功率开关管 ZVS(零电压开关),该变换器实现了DC-DC高增益和整流二极管ZCS(零电流开关),降低了损耗,同时,该变换器对负载提供全周期连续能量传递,提高 了变压器磁芯的利用率,进一步提高了效率,单变压器和无输出滤波电感的设计,配合DSP控制策略,缩小了整机的重量和体积,提高了功率密度,本文详细分析了该变换器的工作原理、控制策略和软开关条件,并通过实验验证了理论分析的正确性。     

基于LPC2214的ZVZCS-PWM全桥变换控制器的研究

针对传统ZVZCS-PWMDC／DC全桥变换器在实现滞后桥臂开关管零电流开关过程中,存在着辅助谐振电路附加损耗较大,软开关实现方式复杂,功率开关管电压应力和电流应力高等缺点,介绍了一种新型次级箝位移相控制的ZVZCSPWMDC／DC全桥变换器。文中分析了该变换器实现软开关的原理,同时设计了变换器数字控制系统,控制器采用LPC2214型ARM芯片,并通过一台实验样机验证了这种软开关变换器相关理论的正确性以及该数字控制系统的可行性。     

一种采用无源辅助电路的移相全桥变换器

文章研究了一种采用无源辅助电路的零电压开关移相全桥变换器,它是在传统全桥拓扑上加入了由电容和电感组成的无源辅助电路,从而可以在整个输入电压和全负载范围内实现原边所有开关管的零电压开关。文中详细分析了该变换器的工作原理及其特性,并对辅助电路参数进行了设计。在此基础上,设计完成了一台1.2kW（50V/24A）,开关频率为100kHz的样机,实验结果验证了该变换器的优越性。     

LLC谐振半桥变换器的设计

LLC谐振半桥变换器可以在全电压范围内、全负载条件下使得初级端 MOSFET实现ZVS（零电压开关）,次级整流二极管实现ZCS（零电流开关）,减少了开关损耗,大大提高了效率。而且在输入电压和负载范围变化比较大的情况下,其开关频率变化较小,有利于主参数的设计。这种变换器通常应用在高频功率变换领域。文中首先使用 FHA（基波近似原理）进行 LLC谐振半桥变换器的建模,然后分析了如何对变换器中的电气参数进行选择,最后设计了一个工作在70~150 kHz频率下300 W的 LLC谐振变换器。     

具有自驱动有源缓冲器的GaN基高效准谐振反激式功率变换器

提出了一种具有自驱动有源缓冲器的GaN基高效准谐振(QR)反激式功率变换器,以解决准谐振反激式功率变换器中开关管关断时电压过高的问题。电路以GaN高电子迁移率晶体管(HEMT)器件为主开关管和同步整流器开关管,自驱动有源缓冲器由钳位电容和有源开关管组成。该变换器在主开关管关断期间将开关管的电压浪涌钳位为恒定电压,由于有源开关管驱动信号由变压器的次级侧电流控制,因此不需要单独的控制电路。为验证所提出的变换器和控制电路的有效性,搭建了一个60 W的AC-DC功率变换器,测试结果表明,主开关管的最大电压浪涌约为450 V,具有高达91.6%的能量转换效率。     

Boost ZCT-PWM变换器的改进及仿真分析

针对传统的Boost ZCT-PWM变换器中存在的主开关管硬开通和辅助开关管硬关断的问题,提出一种改进型的Boost ZCT-PWM变换器,使主开关管零电流开通,辅助开关管零电流通断,并且特别适用于IGBT作为开关器件的高电压、大功率应用场合。分析电路的工作原理并用PSpice仿真软件进行仿真研究。仿真结果表明所有开关器件实现了软开关,变换器的效率得到提高。     

A single-stage power factor correction AC/DC converter based on zero voltage switching full bridge topology with two series-connected transformers

A single-stage power factor correction ac/dc converter based on zero voltage switching (ZVS) full bridge topology with two series-connected transformers is proposed in this paper. The proposed converter offers a very wide ZVS range due to the configuration of two series-connected transformers. It features a high efficiency over wide load ranges. Furthermore, it shows the low voltage stress on a dc link capacitor. The proposed converter also gives the high power factor and low input current harmonics complied with IEC 61000-3-2 Class D requirements by integrating a boost stage operated in a discontinuous current mode. The ZVS conditions, large signal modeling, and design procedure are discussed in detail. Experimental results are presented to show the validity of the proposed converter.     

基于UCC2892和LTC3900的开关电源设计

有源钳位正激变换器可以实现零电压开关（ZVS）,降低功率开关损耗;同步整流可以提高低压大电流输出的开关电源的效率。介绍了一种基于有源钳位脉宽调制控制器UCC2892和同步整流控制器LTC3900的正激开关电源设计。     

Performance characteristics of the full-bridge zero voltageswitching PWM resonant converter

The authors present the exact analysis of the full-bridge zero voltage switching (ZVS) pulse width modulated (PWM) converter by using the state-plane technique. Based on the analysis, they derive the necessary conditions for ZVS operation and the performance characteristics of the converter in terms of characteristic curves from which the converter design procedure can be formulated. The performances of the converter operating outside the limits of ZVS operation, including the switching loss and the attainable efficiency under different load conditions, are also given. The analytical work is confirmed by experimental results     

Analysis and Design for a New ZVS DC–DC Converter With Active Clamping

A new zero voltage switching (ZVS) boost converter is presented in this paper. By using an auxiliary switch and a capacitor, ZVS for all switches is achieved with an auxiliary winding in one magnetic core. A small diode is added to eliminate the voltage ringing across the main rectifier diode. This clamping technique can also be utilized in other dc-dc converters, and a family of new ZVS dc-dc converter is derived. A prototype (500 W/193 kHz) is made to verify the theoretical analysis. The efficiency is higher than 94% at 90-V input at full load     

A self core reset and zero voltage switching forward convertertopology

A self core reset and zero voltage switching (ZVS) forward converter topology is presented in this paper. By employing a simple auxiliary circuit, the proposed topology is able to achieve self reset of the power transformer without the use of the conventional tertiary reset winding, and its main switch can be turned on and turned off under ZVS independent of line and load conditions. This simplifies the power transformer, and the switching losses are substantially removed to improve the overall efficiency. Steady state analysis of the circuit is performed. Based on the analysis, a design procedure is presented, and the effects of the circuit parameters on the flux excursion of the power transformer are investigated to make sure self reset can be achieved without increasing the core losses. Simulation and experiment on a 5 V, 100 W prototype circuit operated at 200 kHz are carried out to verify the design, about 5% higher overall efficiency is obtained in the prototype converter than in its conventional counterpart     

Analysis and design-optimization of LCC resonant inverter forhigh-frequency AC distributed power system

The analysis and design of an LCC resonant inverter for a 20 kHz AC distributed power system are presented. Several resonant converter topologies are assessed to determine their suitability for high efficiency power conversion, under resistive and reactive loads. Two LCC-resonant inverter designs were implemented. One with all switches operating with zero voltage switching (ZVS), and another with two switches operating with ZVS and two switches with zero current switching (ZCS). The experimental results are presented along with a performance comparison of the two versions     

Analysis and design considerations of a load and line independent zero voltage switching full bridge DC/DC converter topology

The analysis and design of a zero voltage switching (ZVS) full bridge DC/DC power converter topology is presented in this paper. The converter topology presented here employs an asymmetrical auxiliary circuit consisting of a few passive components. With this auxiliary circuit, the full bridge converter can achieve ZVS independent of line and load conditions. The operating principle of the circuit is demonstrated, and the steady state analysis is performed. Based on the analysis, a criterion for optimal design is given. Experiment and simulation on a 350-400 V to 55 V, 500 W prototype converter operated at 100 kHz verify the design and show an overall efficiency of greater than 97% at full load.     

Analysis and design of phase shift full bridge converter with series-connected two transformers

A new phase shift full bridge (PSFB) converter with series-connected two transformers is proposed. The proposed converter shows wide zero voltage switching (ZVS) ranges and no output inductor is needed since each transformer individually acts as an inductor or a transformer during different times of the switching cycle. The operational principle, large signal modeling, and design equations are presented. Experimental results demonstrate that the proposed converter can achieve a significant improvement in the efficiency for a 100W (5 V, 20 A) telecommunication on-board power supply.     

新颖的含PFC的PWM ZVS AC-DC变换器

提出了一种新的具有功率因数补偿(PFC)功能的零电压开关(ZVS)AC-DC变换器,该变换器基于不连续导电模式(DCM)下的Boost环节实现PFC功能,但其具有ZVS机制,从而解决了DCM下因开关关断大的峰值电流引起的关断损耗高、EMI严重的问题,同时还消除了由于开关的寄生电容引起的开通损耗.该变换器可以采用通用控制芯片并工作在PWM模式.文中分析了提出变换器的工作原理,并给出了基本设计原则.模拟和实验结果证明了提出的电路是可行的.     

An improved full-bridge zero-voltage-switched PWM converter using asaturable inductor

The saturable inductor is employed in the full-bridge (FB) zero voltage switched (ZVS) pulse width modulated (PWM) power converter to improve its performance. The current and voltage stresses of the switches as well as parasitic oscillations are significantly reduced compared to those of the conventional FB-ZVS-PWM power converter. The qualitative analysis is presented and is verified on a 500 kHz, 5 V/40 A converter