MMC-Topology for High-Current and Low-Voltage Applications with Minimal Number of Submodules, Reduced Switching and Capacitor Losses

Due to recent developments in MMCs, they are used in many medium-voltage and high-power applications today, but efficient and modular solutions for high-power at low-voltage such as for electrolysis are still required. The proposed Y-MMC converts the grid AC-voltage into a DC-voltages, and an LLC converter is connected to each submodule capacitor to provide the required current to the DC-load. This paper proposes a topology that uses only half the number of submodules and moreover to reduce the effective switching frequency by a third, while preserving the same THD und output power of an YY-MMC.