EXTENSION OF FOURIER TRANSFORM FOR VERY FAST REFERENCE GENERATION OF UPQC

The Unified Power Quality Conditioner (UPQC) has composed of two back to back connected series and parallel Active Power Filters. It can be used in a power distribution network by unbalanced and distorted voltages and currents to provide balanced and sinusoidal source currents and load voltages. This paper proposes a fast reference signal generation method for Unified Power Quality Conditioner. Main principle of the proposed control system is based on the Fourier transform theory. Fourier transform can be used in unbalanced and harmonic conditions for the extraction of reference signals. But, its settling down time is one cycle which results in week capability in dynamic condition. The scope of this paper is extending the general Fourier transform for increasing its response speed twelve times. Proposed approach named Very Fast Fourier Transform (VFFT) can be used in distorted three phase systems as a useful tool for reference generation of the UPQC. Results validate the proposed theory capability in reference generation and power quality compensation of a typical distribution system in sag, swell, and harmonized conditions in the presence of dynamic loads. Comparison between general and extended Fourier transform shows increase in the reference signal generation speed.