A Multi-Modular System Based On Parallel-Connected Multilevel Flying Capacitor Converters Controlled with Fundamental Frequency SPWM

The operation performance of a multi-modular system based on parallel-connected multilevel flying capacitor (FC) converters controlled with the fundamental frequency sinusodial pulse-width modulation (FF-SPWM) method is analyzed in this paper. A controller is designed to mitigate the circulating current among converter modules when a phase-shifting SPWM method is utilised in order to reduce the output voltage harmonics. The proposed system exhibits lower power losses when compared with the higher frequency SPWM-controlled single-modlue multilevel FC converter or higher frequency SPWM-controlled two-level conventional converter. Simulations with two five-level FC converter modules are carried out to verify the proposed multi-modular system and its performance under the proposed modified control scheme. The results confirm the attractiveness of the proposed system.