A comparison of single-phase p-q theory and UVT based control algorithms for single-phase UPQC

Abstract

This paper employs a single-phase unified quality conditioner (UPQC), an integration of shunt and series active filters (APF), to perform voltage and supply current harmonics mitigation and power factor correction. Both the shunt and series APFs are realized using a single-phase, two leg voltage source inverter (VSI). For the series APF the control strategy is based on Unit Vector Template (UVT), while a comparison is made for the two control strategies namely UVT and single-phase p-q theory for shunt APF. In both of the control strategies the control is made over the fundamental supply current and fundamental supply voltage instead of the fast changing AFs current and voltage, thereby reducing the computational delay and number of required sensors. A dynamic model of the UPQC is developed in the MATLAB/SIMULINK enviournment and the simulation results demonstrating the power quality improvement in the system are presented for distorted supply and a combination of linear and non-linear load.