A Novel Online Method for Monitoring the Junction Temperature Based on the Input and Output of the Inverter

Abstract

Junction temperature is an important performance parameter for the operation of power semiconductor devices and it is also one of the main factors leading to device failure. This paper proposes a novel online method for monitoring the junction temperature based on the input and output of the inverter. By obtaining the input and output voltage and current of the inverter, the turn-off transient waveform of each power device can be extracted to calculate the turn-off loss. Then the reliability state monitoring of the power device can be realized according to the Eoff - Ic- Tj mapping table. Results show that this method can obtain the turn-off loss Eoff in each control cycle to predict and monitor the real-time junction temperature Tj of each power device. It has the advantages of easy measurement, non-invasiveness and good applicability.