An Approach to Control Modular Multilevel Converters Using Varying Capacitor Voltages

Modular Multilevel Converters (MMCs) are one of the most interesting multilevel converter categories. In this paper, further results based on a model-based cascade MMC control architecture from our previous work, based on the concept of having time-varying average capacitor voltages in the converter arms, are presented. This architecture employs the circulating current control to enable the reduction of both the load current tracking error and harmonic content.