Real-time temperature monitoring and control for power electronic systems under variable active cooling by characterisation of device thermal transfer impedance

This paper presents a technique for predicting the temperature response of a system to arbitrary power dissipation in its constituent elements under variable air-cooling. The thermal impedance is first characterised under the available range of cooling levels. This data is used to predict the thermal response directly. Practical results show good agreement with predicted temperature waveforms. The technique is extended provide active control to maintain steady device temperatures by using power dissipation data without reference to actual temperature. This successfully reduces thermal cycling without requiring additional sensors.