Real-Time Device-Level Simulation of MMC-Based MVDC Traction Power System on MPSoC

Abstract

Real-time simulation of device-level power electronic converter models plays an essential role in traction power systems by allowing accurate prediction of device stresses to design improved control and protection schemes. This paper proposes the electrothermal behavioral power electronic models for the modular multilevel converter (MMC)-based medium voltage direct current (MVDC) traction power system based on the Wiener–Hammerstein configuration. The new configuration introduces the carrier charge prerequisite dynamic transients before device turn-ON or turn-OFF operation. The equivalent carrier charge circuit is also proposed, and the first-order delay assumption of turn-ON and turn-OFF delay time has been proven by the device datasheet. The power electronic device models are implemented in a Xilinx® Zynq® multiprocessing system-on-chip platform. By utilizing hardware and software codesign, both 25- $\mu \text{s}$ time-step system-level and 100-ns time-step device-level transients can be captured in real time within a single device. The three-phase unbalance issue has been resolved by introducing the three-phase to single-phase MMC topology. In the case study, the MMC-based MVDC traction power system has been utilized for the performance of the proposed electrothermal behavioral power electronic models by the off-line simulation models on SaberRD® for device-level transients and PSCAD/EMTDC® for system-level transients.