Three-Phases Flying-Capacitor Multilevel Inverter with Proportional Natural PWM Control

Abstract

The flying-capacitor multilevel inverter is a recently developed topology to ensure a flexible control and a modular design. However, this inverter requires a balanced DC voltage distribution. This can be realized by using a special control leading to natural balancing or by measuring voltages and selecting appropriate switching states. To solve the capacitor voltage-balancing problem a validated solution is suggested in this contribution. It is based on a series of three phases flying-capacitor multilevel inverter model and its proportional control. The proposed command technique originally uses here the Proportional Natural Pulse Width Modulation (PN-PWM) that is compared to the basic N-PWM one. Simulation results satisfy the basic idea that floating voltage can ensure a flexible control and a modular design of flying-capacitor multilevel inverter.