Abstract

Modular Multilevel Converters (MMC) are becoming increasingly popular for HVDC applications and in medium voltage grids and drives. On the contrary, in high-speed low-voltage drives MMCs are typically not considered a good option due to their relatively low power density. In this paper, a new topology is proposed, enhancing the MMC by coupling upper and lower arm sub-modules via Dual Active Bridge (DAB) converters, leading to a sensible reduction of the sub-module capacitance whilst keeping low control complexity. The resulting topology is applied to a high-speed low voltage permanent magnet drive, analyzing the drive startup and its practical operation. Finally, the theoretical claims are validated with simulation results.