A Five-level Hybrid Modular Multilevel Converter with High Efficiency and Power Density

This paper presents a novel five-level hybrid modular multilevel converter (5-L HMMC) for the medium voltage (MV) applications as a member of HMMC family. Compared with the traditional modular multilevel converter (MMC), 5-L HMMC can reduce the number of MMC SMs by fourfold while retaining the excellent output power quality. And it also avoids the limitation of power loop inductance in the traditional 5-L converter due to the line-frequency operation of 5-L stack. Therefore, 5-L HMMC can keep the key benefits of modularity, reliability, and excellent harmonic performance from chain-link, while significantly reducing the power losses, costs, and volume. The feasibility of proposed converter is also verified by the simulation and experimental results.