Real-time electro-thermal simulation of a motor drive system

This paper presents a real-time electro-thermal simulation system which is a novel method of estimating the junction temperatures of power semiconductors. It calculates the junction temperatures of the power semiconductors in real time. The load current and the output voltage of an actual power conversion system are detected to calculate the instantaneous power loss. The detected output voltage is transferred to an FPGA board with a clock of 50 MHz. The PWM signal is reconstructed in the FPGA board using the output voltage of the inverter and it is forwarded to the real-time computer. Using the load current and the reconstructed PWM signal, the power losses and the junction temperatures of the power semiconductors are calculated in the real-time computer. The simulation results are in very good agreement with the experimental results. The junction temperatures of the power semiconductors are estimated under the actual operation using the real-time electro-thermal simulation system.