基于多谐振变换器模块的电力电子直流变压器

Power Electronic DC Transformer Based on Multi-resonant Converter Modules

研究了一种将CLLLC谐振变换器作为子模块(SM)的输入串联输出并联(ISOP)结构的双向隔离DC/DC电力电子变压器系统,以实现高压直流母线到低压直流母线的隔离变换。首先分析了单模块CLLLC谐振变换器的工作原理和增益特性,然后针对基于多CLLLC变换器模块的ISOP系统功率分配不均问题,分析了谐振参数差异对ISOP系统功率分配的影响,并给出了系统正反向运行功率均衡分配的控制策略。最后在1 kW样机上进行了实验研究,分别从软开关实现、动态响应以及功率平衡效果等3个方面对所提理论分析与控制策略有效性进行了实验验证。

A bidirectional isolated DC/DC power electronic transformer system is studied with an input series output parallel(ISOP)structure using a CLLLC resonant converter as a sub-module(SM)to realize the isolated transformation from high-voltage DC bus to low-voltage DC bus.Firstly,the working principle and gain characteristics of singlemodule CLLLC resonant converter are analyzed.Then,the influence of the difference of resonant parameters on the power distribution of ISOP system is analyzed aiming at the problem of the unbalanced power distribution of ISOP system based on multi-CLLLC converter modules,and the control strategy of the balanced power distribution for forward and backward operation of the system is given.Finally,an experimental study is carried out on a 1 kW prototype,and the effectiveness of the proposed theoretical analysis and control strategy is experimentally verified from three aspects:soft switching implementation,dynamic response and power balance effect.