An on-line fault diagnosis method for power electronic drives

This paper describes online techniques for monitoring the health of the two most sensitive components in power electronic systems, namely electrolytic filtering capacitors and controllable semiconductor switches (i.e. MOSFETs and IGBTs). The paper begins with a brief discussion of the primary failure mechanisms for these two types of components. It then presents an online technique designed to measure capacitor ESR, which is a key indicator of capacitor health. Subsequent sections address similar online approaches for tracking the on-state resistance of MOSFETs and the collector-to-emitter saturation voltage of IGBTs. Experimental results demonstrate the effectiveness of these techniques.