Reliability Evaluation for Power Converter of SRM on Fault-Tolerance Capability and Thermal Stress

In this article, a novel reliability evaluation scheme to achieve quantitative reliability calculation for power converter in the whole operation region of switched reluctance motor system is proposed. First, the electrical model is built to obtain electrical stress and fault-tolerance capability in the Matlab/Simulink environment. Second, the thermal circuit model is performed to get the thermal stress of power converter quickly. Third, the dynamical Markov model with a novel failure criterion is applied to achieve quantitative reliability calculation by characterizing the fault-tolerance capability and thermal stress. The proposed failure criterion can simplify the model to decrease the number of states and avoid the divergence of results, especially the interconnected relationship between the three models is key emphasized. Next, the proposed reliability evaluation scheme is carried out to explore the reliability of power converter under different chopping modes. Finally, simulations in conjunction with experiment verify the validity of the proposed reliability evaluation scheme.