LLC谐振变换器电流等效简化模型

Simplified Equivalent Current Model of LLC Resonant Converter

虽然LLC谐振变换器可以通过软开关方式降低工作损耗,但随着电池储能和电动汽车充电等应用需求的提高,以及碳化硅(SiC)和氮化镓(GaN)等宽禁带器件技术的发展,对LLC谐振变换器的工作效率、功率密度以及参数优化和成本提出了更高的要求。通过LLC谐振变换器工作模式的分析,从对损耗影响的角度,筛选出谐振电流最大的工况。通过对谐振电流波形的详细分析和推导,得到电流的等效简化模型。仿真和实验结果表明,相比传统的基波等效法,等效简化模型的误差更小,与时域仿真法相比,计算过程更加简单。

Although LLC resonant converter can reduce energy loss by soft switching,with the application improvement in the field of the battery energy storage and electric vehicle charging,and the development of wide band gap power semiconductor devices,such as silicon carbide(SiC) and gallium nitride(GaN),higher efficiency and power density,more optimized parameters and cost are required.Considering the impact on the loss of power devices and inductive devices,with the analysis of the operating mode of LLC resonant converter,the working condition with the maximum resonant current is selected to calculate the current.By the analysis and derivation of the resonant current waveform,the equivalent simplified model of the current is obtained.The results of simulation and experiment show that the errors of the equivalent simplified model is smaller than the fundamental harmonic approximation,and the calculation process is simpler than the time-domain simulation method.