Abstract
This paper presents a division-summation (D-Σ) digital control based modular multilevel converter. Modular multilevel converters (MMC) have been applied to static synchronous compensators, high-voltage direct-current transmission, wind/solar power generation and battery storage systems. The D-Σ digital control is adopted to track current reference, balance dc-bus capacitor voltage and regulate cell capacitor voltage. The adopted D-Σ digital control can accommodate wide filter inductance variation and take care of source voltage harmonics to achieve fast tracking response and low-distortion output current for the applications of active and reactive power injection and rectification with power factor correction. Simulated and experimental results obtained from the MMC have verified the analysis and discussion.