ZVS隔离型高增益DC/DC变换器

ZVS isolated high step-up DC/DC converter

将传统的L型电流输入隔离型DC/DC变换器与一种DCM(Diode-Capacitor Multiplier)电压增益单元相结合,提出了一种新型ZVS隔离型高增益DC/DC变换器。在继承传统L型电流输入隔离型DC/DC变换器输入电流纹波小、变压器匝数比低等优点的基础上,所提变换器可通过调节DCM增益单元数来调节变换器的输入输出增益比;通过有源箝位电路和漏感的结合,开关均实现了零电压开通,二极管均实现了零电流关断,二极管的反向恢复损耗得到了抑制;借助于所提DCM增益单元,二极管的电压应力以及变压器的绝缘等级得到了有效降低;所有二极管的电压、电流应力均相等,便于散热设计。对变换器的工作原理和性能特点进行了理论分析,并建立了一台输入24 V、输出400 V、功率为200 W的实验样机。实验测试样机最高效率可达95%,验证了理论分析的有效性和正确性。

A ZVS isolated high step-up DC/DC converter is proposed,which combines L-type current-fed isolated DC/DC converter with DCM（Diode-Capacitor Multiplier） cells. The advantages of L-type converter are inherited,such as smaller input current ripple,lower transformer turn-ratio,etc. ;the step-up conversion ratio can be easily adjusted by changing the number of DCM cells;all switches are turned on at zerovoltage,all diodes are turned off with zero-current and the diode reverse-recovery loss is suppressed by combining the active clamp circuit with the inductance leakage;the voltage stress of diode and the insulation class of transformer are lowered due to the DCM cells;all diodes have the same current and voltage stresses to simplify the thermal design. The working principle and performance of the proposed converter are theoretically analyzed and a prototype of 24 V input voltage ,400 V output voltage and 200 W output power is established. The highest efficiency of the prototype reaches 95 % ,verifying the effectiveness and correctness of the theoretical analysis.