FPGA-Based Submicrosecond-Level Real-Time Simulation of Solid-State Transformer With a Switching Frequency of 50 kHz

The switching frequency of power electronic devices has become much higher than before, which brings great challenges to real-time simulators. The small time step in high switching frequency simulations remarkably increases the difficulty to satisfy the real-time requirement. This article realizes the accurate real-time simulation of a solid-state transformer (SST) with a switching frequency of 50 kHz at the time step of 250 ns on a field-programmable gate array (FPGA)-based platform. The hybrid companion circuit modeling method and the compact-electromagnetic transient program (EMTP) algorithm are proposed in this article to make sure that the simulation loop can complete in less than
$1~\mu \text{s}$
. The hybrid companion circuit modeling method can avoid too many digits used in representing simulation variables. The compact-EMTP algorithm is designed by combining the sequential computation tasks of the traditional EMTP to fully utilize the parallelized hardware structure of the FPGA. Besides, a circuit partition method is adopted to further parallelize the circuit solution of the SST circuit. In these ways, the simulation loop of the SST can be completed in 38 clock cycles (about 237.5 ns). The simulation results show that the real-time simulation waveforms are almost consistent with those of the off-line simulation software. Besides, the hardware-in-the-loop (HIL) simulation can also be performed on this platform to test the control functions of the SST.