Design of a Closed-Loop Control to Balance Unequal Temperature Distributions of Parallel-Connected SiC MOSFETs

In this work, a gate driver is presented that allows to balance the temperature of parallel-connected silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) with a closed-loop control. In conventional gate drivers, switching events are often slowed down to avoid unevenly distributed losses of parallel-connected SiC MOSFETs. Due to the reduced switching speed, wide-bandgap (WBG) semiconductor devices are not fully utilized. The presented gate driver selectively delays the individual gate signals of the parallel-connected MOSFETs to influence the switching losses. To balance the temperature of the MOSFETs during operation, a closed-loop control is designed and verified by measurements. The presented gate driver thus enables a balanced stress of parallel-connected MOSFETs and a uniform aging of the MOSFETs. Therefore, the potential of parallel-connected WBG semiconductor devices can be better utilized and a derating of the system is avoided.