A new three-phase inverter built by a low-frequency three-phase inverter in series with three high-frequency single-phase inverters

Abstract

This paper proposes a new type of three-phase inverter built by a line-frequency three-phase bridge inverter in series with three high-frequency single-phase bridge inverters. The three-phase bridge inverter bears the main output power; three single-phase full-bridge inverters are used to improve the system dynamic performance. Compared with the traditional inverter circuit, the circuit can achieve high efficiency and low harmonics at the same time, and it can also reduce the voltage stress of the power switches. This is a new way for the combination of the inverters. The circuit can be controlled easily, so it was easy to be modularized. Simulation model of the new three-phase inverter is presented. High-frequency inverter used PWM modulation and line-frequency inverters worked at the two-logic mode. The correctness and feasibility of the theoretical analysis is verified by the Saber simulation.