Modified generalised integrator based control strategy for solar PV fed UPQC enabling power quality improvement

Abstract

In this work, a modified generalised integrator with DC offset elimination capability is presented herein for the control of a unified power quality conditioner (UPQC) with solar photovoltaic array (SPVA) (UPQC-SPVA) system. Using this method, the fundamental element of load current is extracted, which is processed to generate reference currents for shunt active filter of the UPQC-SPVA system. This control algorithm improves power quality (PQ) such as grid currents balancing, harmonics elimination, compensation of reactive power, grid voltage sag and voltage swell mitigation. This system gives clean energy benefits along with PQ improvement by an integration of solar PV array at the DC link of UPQC. Simulation results are depicted to evaluate the performance of the UPQC in MATLAB/Simulink environment under presence of local non-linear load. The performance of UPQC-SPVA system is evaluated experimentally on a prototype in the laboratory and test results are found satisfactory for various disturbances like grid voltage sag/swell, load unbalancing, harmonics compensation and solar irradiation variation. The total harmonic distortion of the grid current is attained within limits of the IEEE-519 and IEEE-1159 standards.