原边绕组分组连接的IPOP型LLC谐振变换器均流方式

IPOP LLC Resonant Converter in Current Sharing Mode with Primary Winding Grouping Connection

输入并联输出并联IPOP(input parallel output parallel)型LLC谐振变换器由于谐振元件的参数偏差,导致各相所分配到的等效负载不均匀,进而造成不均流现象。对此提出一种将变压器的原边绕组分组连接的方式,实现了各相负载电流的平均分配。采用基波近似法对该方式的均流原理进行分析,给出谐振参数的偏差与负载电流不平衡度之间的关系。采用四组数据进行仿真计算对比,在谐振电感和谐振电容偏差10%的情况下,传统两相并联LLC谐振变换器不均流度高达99.1%,而新结构实现了负载电流平衡。搭建了输出功率为960 W的两相并联LLC谐振变换器实验样机,验证了原边绕组分组连接方式的有效性。

Due to the parameter errors of resonant components in an input parallel output parallel(IPOP)LLC resonant converter,the equivalent load allocated to each phase is not uniform,which leads to the phenomenon of uneven current flow.To solve this problem,a method of transformer primary winding grouping connection is proposed to realize the average allocation of load current in each phase.The principle of current sharing is analyzed by the first harmonic approximation method,and the relationship between resonance parameter errors and load current imbalance degree is given.Four sets of data are compared through simulations.Under the condition of 10%error between resonant inductance and resonant capacitor,the traditional two-phase parallel LLC resonant converter has an imbalance current degree up to 99.1%,while the novel structure realizes the balance of load current.An experimental prototype of two-phase parallel LLC resonant converter with 960 W output power was built,and results verified the effectiveness of the grouping connection mode of primary winding.