Design and Implementation of a Control for Solar PV Fed Unified Power Quality Conditioner

Abstract

In this work, a solar photovoltaic (PV) array-integrated unified power quality conditioner (PV-UPQC) system is presented for power quality (PQ) improvement. Major task in the control of UPQC is generation of reference signal. The control algorithms in time domain (TD) and frequency domain (FD) do not consider DC offset present in the input signal and this got affected in the reference signal generation. A control algorithm based on modified second-order generalized integrator (MSOGI) with DC offset elimination capability is presented in this work. This MSOGI is integrated with conventional pq-theory-based control for extracting in phase fundamental and quadrature fundamental component of distorted input signal and for eliminating DC offset present in the input signal. The dynamic performance of the system is evaluated under various dynamic conditions like grid voltage sag and swell and change in solar irradiation in MATLAB Simulink. The proposed system improves power quality and generates clean energy from PV array and also enables operation of the system in the absence of grid. The total harmonic distortion (THD) of system is limited according to the IEEE-519 and IEEE-1159 standards.