Full bridge level doubling network assisted multilevel DC link inverter

Abstract

A full bridge level-doubling-network (FBLDN) for symmetric cascaded half bridge based multilevel-dc-link inverter is proposed in this work. FBLDN is formed by using a full bridge with floating capacitor. DC-bus of FBLDN reaches desired voltage from any arbitrary initial voltage without any closed-loop control. FBLDN doubles the number of levels in output voltage, hence considerably increases the resolution. Over a complete cycle, FBLDN neither absorbs, nor delivers energy to the rest of the circuit. This topological configuration is developed in order to reduce the total number of switches and simplify the construction of phase-shifting transformer for the isolated DC-sources. Addition to this, the topology is expected to improve efficiency by significantly reducing the number of switches in conduction-path. Operation of the topology is validated by using a simulation-model developed in MATLAB/ Simulink. Simulation result matches well with theory.