A Novel Fixed Switching Frequency Control Strategy for the Modular Multilevel Converter in the ABC Reference Frame

Abstract

This work presents a model of the three-phase three-wire MMC that considers the coupling between the arm currents. Additionally, it also presents a novel decoupled fixed frequency control strategy in the ABC frame, for a three-phase three-wire grid connected MMC, which separately: i) regulates the sum of the upper and lower arm DC voltages, for each converter phase, ii) tracks the grid currents and iii) balances the individual SM DC voltages. The effectiveness of the proposed control method is confirmed by simulation results.