Single-Phase to Three-Phase Converters With Two Parallel Single-Phase Rectifiers and Reduced Switch Count

This paper presents two single-phase to three-phase conversion systems for a three-phase load application. The load is connected to a single-phase grid through an ac-dc-ac single-phase to three-phase converter. The single-phase rectifier is composed of two parallel single-phase half-bridge rectifiers. The first proposed topology is composed of a full-bridge three-phase inverter, i.e., three-leg inverter, while the other topology is composed of a two-leg inverter. Suitable modeling, including the circulation current, and control strategy are presented. A pulsewidth modulation (PWM) technique using a single or double carriers PWM implementation is presented. Proposed topologies permit to improve the harmonic distortion. In addition, the P5L converter can reduce the converter power losses. Finally, simulation and experimental results are presented for validation purposes.

I. Introduction

Brazil is a country with continental dimensions and in some regions (rural areas or remote locations) the power distribution system is typically a single-phase type. The cost to change from a single-phase to a three-phase power system is often high due to the high cost associated with a three-phase extension [1] . In rural or remote areas, the use of three-phase induction machines is preferred instead of single-phase induction machines due to its advantages such as low cost, lower volume, redundancy, etc. [1]–[3]. However, even if a three-phase voltage source is available, a power converter is needed to allow speed or torque control of the induction motor drive. But, if only a single-phase utility is available, a single-phase to three-phase (1ph-to-3ph) converter is indispensable to feed a three-phase motor. Furthermore, nowadays some rural loads, e.g., electronic power converters, computers, communications equipment, etc., demand high power quality with sinusoidal balanced three-phase voltages [4], [5].