Voltage and current balancing control of WBG multilevel converters for aeronautic applications

Abstract

Voltage balancing of flying capacitor multilevel converter (FCMC) is one of difficult criterion for the design and using FCMC, particularity with high switching frequency of Wide Band Gap semi-conductor component (SiC and GaN). The aim of this paper is to analyze the voltage-current balancing characteristic of a series-parallel multilevel converter when it is operated under Phase-Shifted PWM (PS-PWM). The natural balancing of open-loop PS-PWM may not be robust and efficiency to keep the converter stable under different transient conditions. Therefore, the paper proposes a closed-loop PS-PWM control method using a voltage and current balancing algorithm. Furthermore, calculations of P and PI controllers are presented for closed-loop control of voltage and current. Simulation results from a three-phase seven-level series-parallel converter are presented.