Reliability improvement of power inverters for low-speed high-power motor drives

Reliability of power inverters is of paramount importance in safety-critical applications, such as electric vehicles, electric aircrafts, and the like. A failure of a semiconductor device may cause cascaded faults in the power inverters and thus the systems or even lead to catastrophic disasters. Particularly, for low-speed high-power motor-drive applications, the power cycling lifetime of semiconductor device and thus the power inverters will be subject to dramatic degradation during long time of heavy-duty operation, which in fact has received little attention over the past years. In this paper, a novel discontinuous pulse width modulation (NDPWM) strategy will be investigated to improve the power cycling lifetime of MOSFET-based power inverters for low-speed high-power motor-drive applications. Simulation and experimental results verified the efficacy of the NDPWM method, and performance comparison is conducted with the traditional SVPWM and DPWM methods.