具有有源缓冲电路的软开关脉宽调制式变流器

提出了一种新的零电压转换脉宽调制式(PWM)直流——直流变流器．该变流器加设了一个新的有源缓冲器．该变流器中所有半导体器件都能在精确的或接近于零电压开关(ZVS)或零电流开关(ZCS)的情况下开通和关断．主开关和主二极管中无附加的电压和电流应力出现，辅助开关和辅助二极管中出现的电压和电流应力也在容许值之内．该变流器结构简单，成本低，易于控制，在轻载条件下也能正常运行．文章详细分析了其工作原理，提出了有源缓冲单元电路的设计过程，并通过一个脉宽调制式升压变流器的实验原型验证了该变流器的预期工作原理和理论分析．在满输出功率情况下，其主开关的损耗和整个电路的损耗大大降低，由此提升了变流器的总效率。

AN ACTIVE SNUBBER SOFT SWITCHING CONVERTER WITH PWM

This paper presented a novel zero voltage transition pulse width modulation (PWM) dc-dc converter. A new active snubber is added in the converter. In the proposed converter all of the semiconductor devices are turned on and off under exact or near zero voltage switching (ZVS) and/or zero current switching (ZVS). There aren't any additional voltage and current stresses on the main switch and main diode. The auxiliary switch and auxiliary diodes are subjected to voltage and current values at allowable levels. The proposed converter is simple in structure, low in cost, and easy in control. It can also operate at light load conditions. The operating principles of the converter are analyzed in detail in the paper, and a design procedure of the proposed active snubber is also presented. The predicted operating principles and theoretical analysis of the proposed converter are verified with a prototype a boost converter with insulated gate bipolar transistor (IGBT). At full output power in the converter, the main switch loss and the total circuit loss is reduced significantly, so the overall efficiency of the converter increases.