Voltage balancing scheme for flying capacitor multilevel converters

This study proposes a voltage balancing scheme for flying capacitors multilevel converters. The strategy is based on the redundancy of switching states. By using analytic expressions, the authors study the balancing properties of each switching state. Then, based on such properties, the authors choose the switching state which drives the capacitor voltages towards their reference values, and simultaneously will ensure the desired voltage level. The method can be particulary attractive for those applications where the typical pulse-width modulation control is not used, as direct torque control, hysteresis control and sliding-modes control. Experimental results demonstrate the effectiveness of the proposed control scheme, in steady and dynamic conditions.