基于SiC MOSFET车载充电机用高频全桥LLC变换器研究

High frequency full-bridge LLC converter with SiC MOSFET used in on-board EV charger

为了在满足较高的功率密度要求下,设计适应电动汽车用的锂离子电池充电机,提出了一种基于碳化硅MOSFET的高频全桥LLC变换器。针对电动汽车动力电池的充放电特性,对锂离子电池在恒电流充电模式通过基于基波等效法进行建模,并在此基础上研究设计了变换器在高频工作状态变压换器谐振参数。设计搭建了一台最大输出功率6 600 W,输出电压为300 V到450 V的全碳化硅LLC变换器。实验结果表明:在减小了无源器件体积的前提下,该变换器达到了较高的效率(峰值效率达到了98.4%),总体上较大地提高了变换器的功率密度。

In order to achieve higher efficiency and higher power density for an onboard lithium-ion battery charger of electric vehicle,an inductor-inductor-capacitor（LLC） resonant dc-dc converter design procedure with SiC MOSFET was presented.According to the characteristic of Charging profile of lithum-ion battery pack,a design methodology based on fundamental harmonic approximation was proposed and validated through experiments on a prototype converting 800 V from the input to an output voltage range of 300 V-450 V at 6.6 kW.The results indicate that under the premise of lowering the volume of passive components,the peak efficiency can reach 98.4% and the design procedure can improve the power density.