A Resonant hybrid multilevel inverter

Abstract

A high efficiency resonant multilevel inverter for motor drive applications is proposed in this paper. It consists of an Open-end Winding AC machine connected from one side to a three-level inverter and on the other side to a resonant DC link inverter. The main three level inverter is low frequency modulated and manages the entire active power while the resonant DC link inverter works as an active power filter. The obtained configuration can operate at high switching frequency because switching power losses are minimized on the main inverter thanks to a simple step modulation and on the auxiliary one because of zero voltage switching. A sigma-delta modulation is adopted on the auxiliary inverter, while a proportional resonant regulator manages the load current. Simulation tests demonstrate the effectiveness of the proposed configuration.