In Situ Full-Field Deformation Characterization of Power Module and FEA Model Calibration Based on Stereo Digital Image Methodology

Abstract

Due to the increasing concern for the global climate problem, the electric vehicle has drawn considerable attention. The power module with high reliability is the key to the deployment and development of the electric vehicle. However, in-depth evaluations, such as the tedious power cycling, are generally required to verify the reliability of the power module prior to putting it into the field application. Therefore, to determine the failure mechanism and evaluate the reliability of the power module, the in situ full-field characterization with 3-dimensional (3-D) deformation under the field application is essential. Besides, the characterization results can also provide a reference for the finite element analysis (FEA) model and further assess the reliability of the power module. In this paper, the deformation mechanism and multi-physics simulation of the power module are comprehensively studied. To achieve the 3-D full-field characterization of the deformation, the stereo digital image correlation (DIC) methodology is proposed to measure the out-of-plane and in-plane deformation. Additionally, in order to validate the feasibility of the proposed method, an active power cycle test rig that periodically heats up the power module by its own dissipation losses is constituted by the introduction of a front-to-front converter. The experimental results show that the maximum deformation occurs on the central surface of the focused zone while the edge bears a minimum deformation. Comparative evaluation indicates that the maximal error between experimental and simulation results is within 5%, thus enable the effectiveness of the FEA simulation model.