Harmonic current extraction and compensation in three phase three wire system using notch filter

This paper presents a notch filter based extraction of harmonic current and compensation technique in a three phase three wire distribution system using a voltage source converter (VSC). A notch filter is a band reject (band stop) filter which allows most part of frequencies to pass unchanged but attenuates other frequencies to very low levels in a certain range. A notch filter is developed to extract the fundamental component from the polluted load current and VSC provides the necessary compensation. The proposed technique is simple and can easily detect and mitigate harmonic current using shunt compensation. The technique is analyzed and simulated using MATLAB and verified on a prototype three phase three wire system developed in the laboratory. The dSPACE 1104 is used as a digital signal processor to generate necessary gating pulses for VSC. The performance of the proposed technique is found to be quite satisfactory for various aspects of power quality improvement of system.