Six-Leg Single-Phase to Three-Phase Converter

This paper investigates the utilization of two different six-leg configurations of single-phase to three-phase converters. One of the topologies is transformerless and the other is transformer based. The studied converters allow feeding the load voltage with sinusoidal voltages with constant amplitude and frequency, and to operate with sinusoidal grid current with high power factor. The system model and pulse-width modulation techniques for one of the topologies are given. Control strategies for both topologies are provided. The studied topologies are compared with the conventional in terms of dc-link specification, voltages harmonic distortions, semiconductor losses, and other characteristics. Simulation and experimental results are provided to illustrate the operation of the systems.

I. Introduction

In the power distribution systems, the single-phase grid has been considered as an alternative for rural or remote areas [1], due to its lower cost feature, especially when compared with the three-phase solution. In huge countries like Brazil [2], the single-phase grid is quite common due to the large area to be covered. However, connect loads in a three-phase arrangement presents some advantages compared to the single-phase arrangement. Besides, farming operations usually involve three-phase motors. A suitable single-phase to three-phase converter is therefore essential in order to use these motors and to connect three-phase loads.