Dynamic Deformation Oriented Thermo-Mechanical Performance Assessment for Automotive Power Module With Various PWM Schemes

Abstract

Motivated by advances in semiconductor technology and policies from the government, the electric vehicle (EV) has become a promising solution to climate change worldwide. As the core component of the EV, the power module is expected to have high reliability. Considering the different field demands, the power module is generally driven by various pulse width modulation (PWM) schemes. However, how to assess and select the appropriate PWM scheme based on the specific field application is a knotty challenge. In this paper, a new perspective from the dynamic deformation of the power module is proposed to evaluate various PWM schemes. Based on experimental results, the power loss of the power module is calibrated and applied to the finite element analysis (FEA) model to clarify the deformation mechanism. Besides, the deformation measurement platform with high resolution and accuracy based on the confocal sensor is customized. Comparative results demonstrate that the FEA simulation model presents high agreement with the experimental results in terms of the maximum temperature and overall deformation, which confirm the accuracy of the power loss model. Furthermore, the continuous PWMs (CPWMs) generate the highest temperature and deformation, while the discrete PWM2 (DPWM2) presents the lowest temperature and deformation. The hysteresis curve of the power module consisting of the temperature and deformation is observed. The DPWM2 shows a 53% reduction in the closed area of the hysteresis curve compared to CPWMs, which indicates that it causes the lowest damage degree to the power module. In addition, the experimental results of the partial deformation demonstrate that the DPWM2 also has the lowest partial deformation among various PWMs. Generally, the DPWM2 is recommended when the DPWMs are enabled in the high-speed region of the EV.