Thermal Analysis of Integrated Power Supply in Parallel with Si IGBT and SiC MOSFET Inverter Based on PLECS

Inverters are an important part of the electric drive system of new energy electric vehicles. Complex working conditions and user demands put forward more demanding requirements on the capacity, efficiency, cost, power density and reliability of the main drive inverters of electric vehicles. It is difficult to take into account these performance indicators if the inverter is composed of silicon-based power devices or silicon carbide power devices alone. In order to solve these problems effectively, the integrated power supply composed of Si IGBT inverter and SiC MOSFET inverter in parallel is a feasible solution. Due to the coupling characteristics of different power devices, the related research of this structure is in the preliminary stage. Power loss and junction temperature parameters as key indicators of parallel integrated power supply are not fully and deeply studied. In this paper, the loss of the parallel structure under sinusoidal pulse width modulation is deduced and analyzed, and the circuit model and loss model are built in the simulation software PLECS. The simulation results and theoretical calculation results are verified each other, and the simulation results can be used as the basis for the heat dissipation design of the inverter. Aiming at the parallel structure of the inverter, a multi-objective mathematical model is proposed as the basis for device selection and load power design of the parallel inverter.