A Capacitor Voltage Balancing Method in Modular Multilevel Converter using Selective Mapping

Modular Multilevel Converter (MMC) is an emerging multilevel inverter in the field of medium and high- voltage applications. Balancing the dc capacitor voltage in a module is a challenging task. There are several papers in literature solving the problem. This paper also deals with balancing of capacitor voltages by first sorting the voltages and then driving the switches by comparison result of biased carrier waves and the reference voltages based on the sorted voltages. Phase-disposition PWM is applied with the voltage balancing technique. MATLAB simulation was executed to show the effectiveness of the method on a 9-level MMC using 4 modules in an arm.