Single Stage Three-Phase Solar PV Integrated Unified Power Quality Conditioner (UPQC)

This paper presents a solar PV (photovoltaic)-integrated UPQC (Unified Power Quality Conditioner) that employs a fractional open-circuit algorithm, and it analyses its performance under both steady-state and dynamic operating conditions using MATLAB/Simulink. In the UPQC configuration, the shunt and series Voltage Source Converters (VSCs) are connected back-to-back and share a common DC link. The shunt compensator performs dual functions: it extracts power from the solar PV array and provides current compensation. The series compensator, on the other hand, offers voltage compensation by injecting voltage (in-phase or out-of-phase) into the grid at the Point of Common Coupling (PCC) during voltage sag and swell conditions. A fractional open-circuit algorithm with a single-stage topology is used for maximum power extraction from the PV array. This algorithm is not only easy to implement but also provides smooth, oscillation-free responses. Overall, the proposed system operates as a multifunctional solution, supplying clean energy to the grid while simultaneously improving power quality.