一种改进PWM控制半桥ZVS变换器研究

本文分析了一种半桥软开关直流变换器。与传统半桥电路相比,该电路增加了一个由辅助开关管和一个二级管组成的支路。采用一种改进的PWM控制方法。主开关管不仅工作在对称状态,而且能很好地实现软开关。辅助开关开关管在主开关管关闭期间实现ZVS和ZCS导通,辅助开关管不仅为主开关管实现ZVS创造了条件,而且大大减轻了变压器漏感和主开关管结电容之间的振荡。文中详细分析了该变换器的工作原理,仿真和试验研究表明,该变换器具有优良的性能。

Research on ZVS Half-bridge DO-DO Converter with Modified PWM Control Method

A halfbridge DC-DC converter with zero voltage switching (ZVS) is presented in this paper. Compared with conventional half bridge topology,a branch comprising an auxiliary switch and a diode is added. And by using a modified PWM control method, the two main switches conduct symmetrically and can achieve zero-voltage switching (ZVS) easily. The auxiliary switch conducts when the two main switch turn off,and it also operates at ZVS and ZCS conditions. This switch not only helps the main switches achieve ZVS, furthermore, it eliminates the oscillation between the transformer leakage inductance and the junction capacitance of two switches. In this paper the converter's operational principle is illustrated in detail. And simulation and experimental research indicate that the converter has good performance.