Dual Capacitor Submodule Arm Multiplexing MMC-SST

The modular multilevel converter-based solid-state transformer (MMC-SST) using a dual active bridge (DAB) structure inevitably incur high economic costs. This paper proposes a dual capacitor submodule arm multiplexing MMC-SST (DCAM-MMC-SST) topology, which reduces the cost by multiplexing submodule’s arm. As compared to the MMC-SST consisting of conventional half-bridge DAB submodules, the presented topology saves half of the insulated gate bipolar transistors (IGBT) and high-frequency transformers, greatly improving the appeal of the topology. Meanwhile, a frequency mixing modulation method of the DCAM-MMC-SST is also thoroughly investigated. Simulation results illustrate the effectiveness of the DCAM-MMC-SST and its associated control method.