Grid Interaction Of a Single-phase Feeder To a Three-phase Converter

Abstract

This paper describes the digital control strategy of a line-interactive single-phase to three-phase converter. A typical application may be in rural areas supplied by a single-wire with earth return power system. Due to the evolution of the agricultural and industry, some of the local loads (as electronic power converters, computers, communication equipments, etc.) require, nowadays, high power quality that is intended as sinusoidal, symmetrical and balanced three-phase voltage. In addition to that, to maximize the power absorbed from the feeder, the proposed converter, i.e. a three-phase pulse width modulated voltage source inverter, provides a unity line-side power factor. Differently from the conventional solutions, that uses a single-phase rectifier plus a three-phase inverter, the proposed power converter does not process totally the load power, but only the fraction needed to equalize the system. As it also does not manage active power, it does not necessarily require a DC source at the DC link. The digital control strategy, some design criteria and experimental results are presented.

Keywords

• Power quality
• rural areas
• single-phase to three-phase converter
• uninterruptible power supply