交错并联LLC谐振变换器的磁集成均流特性研究

Investigation on magnetic integrated current sharing characteristics of interleaved LLC resonant converter

为了扩充容量,LLC谐振变换器多采用两相或多相交错并联结构。然而,由于交错并联LLC谐振变换器中各并联相的谐振元件参数(主要包括谐振电感和谐振电容)不可避免地存在偏差,使得各相LLC谐振变换器之间的电压增益不相等,导致各相电流不均衡。针对这一问题,本文提出一种180°交错并联LLC谐振变换器的磁集成均流方案,通过对各个并联相谐振电感进行磁集成,在不增加额外电路和不改变控制策略的情况下,实现各相LLC电路原边电流和负载电流的自动均衡,不但保持了LLC谐振变换器所固有的软开关特性,而且还提高了效率,并将谐振电感器的数量由两个减少为一个。搭建了输出功率为1kW的两相交错并联磁集成LLC谐振变换器实验样机,验证了磁集成均流方案的有效性。

In order to expand the capacity,LLC resonant converters mostly use two phases or multi phases parallel structure.However,due to the unavoidable deviation of the resonant element parameters(including resonant inductance and resonant capacitance)of each phase in the interleaved LLC resonant converter,the voltage gain of each LLC resonant converter is not equal,resulting in the unbalanced current of each phase.In order to solve this problem,a magnetic integrated current sharing scheme for 180 degree interleaved parallel LLC resonant converter is proposed.By magnetic integration of each resonant inductor,the primary current and load current of each LL circuit can be balanced automatically without any additional circuit and control strategy.It not only maintains the inherent soft switching characteristic of LLC resonant converter,but also improves the efficiency and reduces the number of resonant inductors from two to one.f lkw experimental prototype of two-phase interleaving parallel magnetic integrated LLC resonant converter is built to verify the effectiveness of the current sharing scheme.