An Equivalent Switching Model for FPGA-Based Real-Time Simulation of SiC MOSFET Transient Behaviors in Power Electronic Converters

To enable accurate real-time simulation (RTS) of power electronic converters with small time-step, an innovative transient behavior model for SiC mosfets is proposed in this article. The model represents the mosfet as an equivalent conductance and considers the effects of the switching junction capacitance as well as the gate drive circuit, on the transient behavior of the switching device. By constructing the higher-order state equations of the half-bridge arm as equivalent mathematical equations, the hardware resources required to solve the transient process are greatly reduced. In addition, a detailed implementation of the proposed RTS model based on field programmable gate array (FPGA) is provided. The model simulates the nonlinear characteristics of junction capacitance using look-up tables (LUTs). The model does not contain an iterative solution process and is solved in parallel with external circuits at each time-step. Finally, a double-pulse test circuit and an LLC resonant converter RTS model with a time-step of 10 ns are implemented based on FPGA. The validity and accuracy of the proposed model are verified by comparing the simulation results with the hardware experimental results.