Efficient and Accurate Modeling of Resonant Converter for Real-Time Simulation Application

This paper presents an efficient and accurate modeling method for the real-time or accelerated simulation of resonant converters. The method, first, derives a universal equivalent circuit for each switching bridge based on the switching function method. Afterward, an algorithm is proposed to find exact bridge status at each simulation time-point. The method can be used for i) accelerated simulation mode in CPU, and ii) to achieve a very small simulation time-step in the FPGA-based real-time simulation. The accuracy of the method is validated using a 200 kHz LLC resonant converter case against the reference model obtained from the Simscape Power Systems toolbox, for various operating modes. To further demonstrate the modularity and effectiveness of the method, a step-up cascaded medium voltage converter implemented with 10 LLC converters is considered in the accelerated simulation mode. It is shown that the proposed method is computationally efficient, reducing the simulation time by a factor of 19 for a system including four 10-LLC step-up assemblies, while rendering the same level of accuracy.