Reliability odometer of power semiconductor device used for high performance high power amplifiers

This paper presents a real-time evaluation of power semiconductor devices in a high performance high power amplifier. The proposed method can represent the life status of the semiconductor modules in ‘odometer’ format. A special challenging case are pulsating load applications like an MRI gradient driver system. The general concepts presented have been evaluated in detail for the MRI case. A detailed Cauer thermal network is proposed to estimate the temperature from junction to ambient with the combination of non-ideal heatsink. Rainflow counting method and Palmgren-Miner linear damage accumulation rule are introduced and designed for the on-line cycle counting and real-time lifetime consumption estimation. The paper explains the design of the method considerations to minimize the computing time and memory requirements different from standard off line or post analysis approaches. Simulation models and hardware prototype are built to validate the design and analysis.