Performance evaluation of digital filters in distribution static compensator for non‐linear loads

Abstract

This study deals with the performance analysis of three digital filters viz. multiple complex coefficient filter (MCCF), moving average (MA) and Butterworth in distribution static compensator (DSTATCOM) for non-linear loads. The filters are designed to extract the fundamental component of load current and tested in the closed-loop control of DSTATCOM. The filters are used to extract fundamental signal from the non-linear distorted source/load currents and all the lower-order harmonics present in the non-linear current drawn by the load. The performance of MCCF filter is compared to conventional filters such as Butterworth and MA filter. The detailed frequency response of MCCF is analysed. The magnitude and phase response plot of the MCCF suggest that this filter has unity gain and zero phase shift at fundamental frequency. All the three filters are implemented on a DSTATCOM for three-phase, three-wire distribution system. The DSTATCOM is implemented using a three-phase voltage source converter controlled using dSPACE 1104 controller. The closed-loop operation of DSTATCOM designed using MCCF is tested under steady state and dynamic system conditions. Simulation and experimental results are demonstrated with relevant waveforms under different load conditions.