Real-time FPGA Simulation of Dual Active Bridge Converter with SiC MOSFET Device Model

Abstract

This paper presents an FPGA-based real-time simulation model of the dual active bridge (DAB) converter employing a silicon carbide (SiC) MOSFET dynamic device model. The threshold-based model utilizes the Shichman and Hodges equations with voltage-dependent non-linear device capacitances to obtain an accurate model for the turn-off switching transients of the device. The switching transient dictates the rise and fall times of the DAB inductor voltage and output current and it will also be reflected in the output capacitor voltage ripple. Key device states - such as drain-source voltage, drain-current and turn-off delays - and converter states - such as the leakage inductor voltage and output capacitor voltage ripple - can be realized in real-time and monitored with an analog to digital converter in the FPGA board. Such models are beneficial for rapid and cost-effective manufacturing of high-power SiC-based converters such as the DAB. The simulation results are verified experimentally on a 3.3kV/750A SiC MOSFET module, showing good correspondence.