Transient Current Sharing Method for Parallel SiC MOSFETs Based on Gate-Source Voltage Difference

In the design of high-power converters, significant parameter dispersion among different SiC MOSFET devices can cause substantial current differences during switching when devices are directly paralleled. To address this issue, a method is proposed to suppress transient current imbalance based on gate-source voltage compensation. First, the impact mechanism of threshold voltage differences on transient current imbalance during the switching of parallel SiC MOSFETs is analysed, and the role of gate-source voltage differences in current sharing is explored. The proposed method introduces a gate current extraction structure during the on-state and a current injection structure during the off-state to generate gate-source voltage differences between two devices, thereby eliminating the current differences caused by inconsistent device turn-on sequences. Compensation parameters are determined by analysing the mathematical model of gate-source voltage differences during switching transients. Finally, simulation analysis and experimental tests using LTspice simulation software and a parallel double-pulse test platform demonstrate that the proposed current sharing method significantly improves transient current imbalance between parallel devices.