Switching Transient Simulation and System Efficiency Evaluation of Megawatt Power Electronics Converter With Discrete State Event-Driven Approach

The design and analysis of megawatt power electronics systems calls for an accurate and efficient simulation approach that can consider the switching transients. However, the state-of-the-art simulation methods and tools exhibit low efficiency in megawatt power electronics systems, even with ideal switch model. It is hardly possible to perform physical-switch-model-based simulation due to the time cost and the convergence issue. This paper proposes a switching transient simulation approach based on the discrete state event-driven approach. The proposed method is composed of a switch-pair-based modeling method and a time-scale-decoupling simulation method. In the example of a 2 MW power electronics transformer composed of 576 semiconductor switches, the proposed method enables the switching transient simulation of a 0.2-second dynamic within 10 minutes and is free of convergence problems. The speed is 20-fold faster than commercial software adopting ideal switch model. The accuracy is attested to by comparisons with both experimental and commercial software results. Meanwhile, this paper demonstrates the application in system efficiency evaluation. Due to the speed gain and the ability of capturing switching transients, the proposed method enables simulation of the efficiency curve, and hence the locating of the maximum efficiency point and optimized design of the conversion system.