零电压开关PWM组合式三电平变换器的箝位策略

Voltage Clamping Scheme for Zero-voltage-switching PWM Combined Three-level Converter

零电压开关(zero-voltage-switching,ZVS)PWM组合式三电平变换器利用变压器的漏感(或外加谐振电感)和开关管的结电容可以实现开关管的ZVS,但在副边整流二极管存在反向恢复引起的电压振荡和尖峰。为了解决该问题,该文将2种基本箝位网络应用于该变换器中,提出一族箝位策略;在这些箝位策略中选择出2种可行的方案,不仅有效地消除在三电平模式和两电平模式下副边整流管的电压尖峰,同时保留原有变换器的所有优点。该文分析了引入箝位网络后变换器的工作原理和特点,并进行了实验验证。

Zero-Voltage-switching （ZVS） PWM combined three-level （C-TL） converter realizes ZVS for the switches with the use of the leakage inductances or resonant inductance and the output capacitors of the switches, however the rectifier diodes still suffer the voltage oscillation resulted by the reverse recovery. In order to solve this problem, this paper introduces two basic clamping networks to ZVS PWM C-TL converter and proposes a family of voltage clamping schemes. Two feasible schemes are adopted which can not only eliminate the voltage oscillation and spike both in 3L and 2L mode, but keep all the advantages of the original converter. A prototype converter has been tested for the verification of the principles and advantages.