A Study on Real Time IGBT Junction Temperature Estimation Using the NTC and Calculation of Power Losses in the Automotive Inverter System

This paper proposes a junction temperature estimation algorithm for the insulated gate bipolar transistor (IGBT) based on a power loss calculation and a thermal impedance model for inverter systems. The Simulink model was designed to calculate the power losses of power semiconductor devices and to estimate the junction temperature with a simplified thermal impedance model. This model can estimate the junction temperature up to the transient state, including the steady state. The parameters used to calculate the power losses, the thermal resistance, and the thermal capacitance were optimized for a given inverter to be tested for improving the accuracy. The simulation results and experimental measurement data were compared to verify the proposed junction temperature estimation algorithm. Finally, the algorithm was installed on the inverter controller, and the performance was verified by comparing the real time estimation result with the measured temperature.