公共支路阻抗耦合对碳化硅MOSFET器件并联电流分配的影响及优化

Influence and Optimization of Common Branch Impedance Coupling on Current Sharing of Paralleled SiC MOSFETs

为了评估公共支路阻抗耦合效应对碳化硅MOSFET器件并联动静态电流分配的影响,改善并联器件间电流分配的一致性,首先建立包含关键寄生电阻和寄生电感的等效电路模型,分析公共支路阻抗耦合对并联器件动态和静态电流分配的影响。然后,针对不同应用工况下并联器件个数不同的问题,提出n个器件并联支路阻抗补偿的方法。通过对并联器件的漏极测和源极侧阻抗进行补偿,可以消除公共支路阻抗耦合效应对并联器件动静态电流分配的影响。最后,搭建支路阻抗补偿前和补偿后的仿真电路和实验平台。结果表明,通过对并联器件支路阻抗进行补偿,可提升并联器件动静态电流分配的一致性,验证了该方法的有效性。

To evaluate the influence of common branch impedance coupling on the dynamic and static current distribution of parallel silicon carbide MOSFET devices, and to improve the current sharing among parallel devices, an equivalent circuit model with critical parasitic resistance and parasitic inductance was established firstly, and the influence of common branch impedance coupling on the dynamic and static current distribution of parallel devices was analyzed. Then, aiming at the problem of different number of parallel devices in different application conditions, the method of impedance compensation for the parallel branches of n devices was proposed. By compensating the drain and source side impedance of the parallel devices, the influence of the common branch impedance coupling effect on the dynamic and static current distribution of the parallel device could be eliminated. Finally, the simulation circuit and experimental platform before and after the branch impedance compensation were built. Results show that by compensating the branch impedance of parallel devices, the sharing of dynamic and static current of parallel devices can be improved, which verifies the effectiveness of the method.