一种谐振电感复用型的定频PWM单向谐振变换器

A Constant Frequency PWM Controlled Unidirectional Resonant Converter by Reusing Resonant Inductor

提出一种谐振电感复用型的定频PWM单向谐振变换器。该变换器对谐振电感增加二次绕组与整流二极管,构成输出串联的反激辅助电路,当谐振结束时,通过控制辅助管使谐振电感切换至反激复用模态,实现输出电压的调节。与传统单向谐振变换器相比,该拓扑采用定频PWM控制,因此全输入范围内实现零电压开通与零电流关断,同时可增大励磁电感减小导通损耗,也简化了谐振参数与磁元件的设计,另外钳位电容有效抑制了漏感引起的电压尖峰振荡。详细分析电路拓扑结构、控制方法及工作原理,并推导计算占空比调压关系。在上述理论分析的基础上,通过原理样机(41~53V输入,24V/2A输出)获得的数据结果验证了理论分析的正确性。

This paper proposes a constant frequency PWM controlled unidirectional resonant converter by reusing resonant inductor.To form a flyback auxiliary circuit in series at output,a secondary winding with rectifier diode is added to the resonant inductor.Therefore,the output voltage regulation is achieved by controlling auxiliary switch to reuse resonant inductor operating in flyback mode.Unlike conventional unidirectional resonant converters,the proposed converter adopts constant frequency PWM control.Thus,ZVZCS is realized in full input range.Besides,conduction loss is reduced by increasing magnetizing inductor,and the magnetic components design is simplified.Furthermore,voltage pike caused by leakage inductor is also eliminated due to the clamp capacitor.The topology,control scheme and operating principle are analyzed in detail.The relationship between duty cycle and voltage ratio is calculated.Based on the theoretical analysis,the data obtained by the prototype(41~53V input,24V/2A output)demonstrate the correctness and feasibility.