Current Balancing Methods for a High Power Silicon Carbide Inverter with Paralleled Modules

Abstract

Power module paralleling is a common approach to increase the current capacity. However, paralleled modules often have current sharing issues due to the parameter mismatches. In this work, two high power inverters using paralleled Wolfs peed silicon carbide (SiC) modules in each phase are utilized to study the current sharing issues and validate the effectiveness of the proposed reinforced current balancing method, which is a two-fold approach to address both steady-state and transient current mismatch. The paralleling branches are connected to the load through long cables to suppress the steady-state imbalance using the cable self-inductance. To further compensate the transient current imbalance occurs during every switching period, the modulation index and phase angle of the module reference signal are adjusted. Both simulation and experimental results are presented in this paper to validate the effectiveness of the proposed method.