Reliability Evaluation of Silicon Carbide (SiC) Boost Converter Using Stochastic Model

Abstract

In recent years, power electronics has turned as an inevitable part in aerospace, renewable energy conversion, and automotive industry applications. Although it expands in all dimensions with full potential, the critical applications demand reliability from the safety point of view. So, efforts are being devoted towards the improvement of reliability of power electronic (PE) systems. Field experiences show that power electronic systems are usually one of the most vital parts in terms of lifetime, failure rate, and maintenance cost. There are three important queries to be considered for evaluating its reliability: reason for failure, how to build a reliable power electronic system, and the methods to test and monitor the reliable operation of the system. Taking into account these constraints, in this article, we have brought the detailed reliability evaluation of silicon carbide (SiC)-based boost converter. Compared to silicon devices, SiC power devices have many more advantages such as higher blocking voltages, higher switching frequencies, and higher junction temperatures. The boost converter acts as an interface in photovoltaic systems and regulates the input voltage to the subsequent parts of the power conversion system. A SiC-based boost converter incorporates the advantages of SiC material in the boost converter. Still, the reliability of the system in terms of lifetime, system availability, failure rate, and mean time to failure needs to be analysed before using it in any critical application. In this paper, the components prone to degradation/failure due to operating frequency, operating temperature, and variation in the input voltage have been investigated. A stochastic model called the Markov model has been implemented to find out the system availability. A reliability workbench called isograph has been used to model the entire system. The first-order equations have been solved in MATLAB using Runge–kutta method. The prototype of the SiC boost converter has been built and operated in both closed and open loops at various operating frequencies. The thermal study has been carried out to find out hot spots, and the system performance has been monitored under various operating conditions. The results obtained for various test cases are analysed, validated, and presented.