Discharge Profile-based On-state Voltage Acquisition for Power Semiconductors in EV Traction Inverters

Power semiconductors are an important part of traction inverters, contributing to cost, size, and failure rate on a considerable scale. This paper proposes a practical on-state voltage acquisition method for power semiconductors in electric vehicle (EV) traction applications to facilitate the implementation of health and condition monitoring applications. It is achieved through the DC-link discharging operation mode of the traction inverter after the vehicle is parked, minimizing the new risks posed by data acquisition to system operation, which is critical to the safety of EV applications. In addition, due to the significantly lower dynamics in the discharging mode compared to the normal operation, the sampling requirements for the on-state voltage are greatly reduced. The proposed method can be extended to various traction applications and is promising for EV applications as the required operation condition is an inherently programmed and frequent mode. The proof-of-concept experiments based on a three-phase inverter prototype verify the feasibility and effectiveness of the proposed method.