Hybrid domain-based fast transient thermal evaluation method for power semiconductor modules in EV motor drive

Performance screening and reliability evaluation of electric vehicle (EV) motor drives require fast and precise thermal evaluation of power devices in both steady-state and transient-state analysis. In this paper, a hybrid-domain calculation method is proposed to fulfil the requirement. Firstly, the matrix form model is selected by characterizing the thermal response of an EV module. To quantitatively investigate the speed of different calculation methods, a generalized calculation burden evaluation is conducted based on counting the number of algebraic operations. Both the steady-state and transient-state scenarios for EV motor drives are considered. Accordingly, a hybrid calculation method for transient analysis is proposed by combining the advantages of time-domain and frequency-domain methods. Its advantage is validated by evaluating the elapsed time for a real case. Since numerous evaluation points are required for the performance screening of converters at the early design stage, the proposed method accelerates the thermal evaluation process without reducing the accuracy.