一种新颖的零电压开关PWM三电平直流变换器

在直流变换器中，采用三电平技术可以将输入直流电压减半后加至开关管上，从而减小了开关管上的电压应力，特别适用于高输入电压场合。而带箝位二极管的零电压开关三电平（ZVSTL）直流变换器既可实现零电压开关，又可保证开关管电压应力为输入直流电压的一半。由于箝位二极管的作用，可有效消除副边整流电压尖峰。在此基础上，本文提出了一种新颖的ZVSTL直流变换器。这种变换器将原电路进行简化，去掉了其中的两个续流二极管，可达到与原电路同样的效果。文中分析了该电路的工作原理及实现零电压开关的措施，给出了600W实验样机的实验验证结果，并对该变换器的特点作了简单总结。

Three Level DC/DC Converter of a Novel Zero Voltage Switching PWM

If the three level technology is used in DC/DC converter,then the voltage stress on power switch is half of the input voltage, it can be widely used in medium and high power applications. A zero voltage switching three level (ZVS TL) DC/DC converter with clamp diodes can not only realize zero voltage switching, but also keep the voltage stress on power switch half of the input voltage, it can also get the voltage spike away from the converter. On the basis of the circuit, this paper proposes a novel ZVS TL DC/DC converter in which the two free wheeling diodes are moved. This kind of converter can get the same effect of the former. The paper analyzes the principle of the circuit and gives the ways to realize zero voltage switching. A prototype converter rated at 600 W is implement in the laboratory to verify the principle of the converter. Finally simple conclusions are obtained.