Improvement of Power Quality by Fuzzy Based Transformer less Active Power Filter

Abstract

Unlike traditional passive filters, modern fuzzy based active filters have the following multiple functions; harmonic filtering, damping, isolation and termination, reactive-power control for power factor correction and voltage regulation, load balancing, voltage-flicker reduction, and/or their combinations, totally improving the quality of power. Significant cost reductions in both power semiconductor devices and signal-processing devices have inspired manufactures to put active filters on the market. The proposed system is a combination of parallel and series fuzzy based active filters without transformer. It is suitable for applications where size and weight are critical factors. The model of the system is derived and it is shown that the circulating current observed in the proposed active filter is an important quantity that must be controlled. Simulated and experimental results validate the theoretical considerations.