On-line condition monitoring for MOSFET and IGBT switches in digitally controlled drives

The early detection of incipient faults is desirable in mission-critical applications such as shipboard propulsion drives. This paper presents an on-line condition-monitoring approach for detecting incipient faults in IGBTs and MOSFETs. The proposed algorithm extracts important device features (i.e V_CE,ON and R_DS,ON) and compares them to healthy values recorded over a range of operating conditions. The algorithm is based on principal-components analysis (PCA). An experimental implementation in an IGBT-based drive is described. An on-line feature extraction scheme for MOSFETs is also proposed and demonstrated. This scheme exploits the nature of carrier-based PWM in order simplify the measurement process.