A line-interactive single-phase to three-phase converter system

This paper describes a line-interactive single-phase to three-phase converter. A typical application is in rural areas supplied by the single-wire with earth return system. The traditional objective of feeding a three-phase induction motor is not anymore the main concern for such conversion. Due to the evolution of the agro business, some of the local loads (as electronic power converters, computers, communication equipments, etc.) require high quality power, intended as sinusoidal, symmetrical, and balanced three-phase voltage. Additionally, to maximize the power got from the feeder, the system provides a unitary power factor to the grid. A three-phase VSI-PWM converter is used for this purpose. The power converter does not process all the load power as in the conventional solutions, but only the fraction necessary to regulate the three-phase bus voltage. As it does not manage active power, it is not necessary to have a source at the dc side. The control strategy, design highlights, and experimental results are presented.