Semiconductor Temperature and Condition Monitoring using Gate Driver Integrated Inverter Output Voltage Measurement

Bond-wire lift-off caused by mechanical stress due to thermal cycling is one of the major failures in power electronic systems. Condition monitoring concepts which allow to predict these failures are often based on voltage-drop detection and thermal monitoring. However, solutions to determine the junction temperature and semiconductor voltage drop during operation are rarely addressed. In this paper, a direct semiconductor temperature detection method is proposed which is based on instantaneous semiconductor voltage drop monitoring. A MOS-FET inverter system, equipped with a digital integration based instantaneous output voltage measuring circuit, is extended by software to enables instantaneous semiconductor voltage drop detection. Experimental results demonstrate that the proposed method is feasible for online temperature measurement and detection of increased resistance due to bond wire faults. The voltage measurement resolution is sufficient for dynamic temperature monitoring including fundamental frequency temperature cycles at low frequency.