Reduced Voltage Sensors Based UPQC Tied Solar PV System Enabling Power Quality Improvement

Abstract

This work presents an enhanced second-order generalized integrator (ESOGI) based control method for the grid integrated unified power quality conditioner (UPQC) with a solar photovoltaic (PV) system. The objective of this work is to improve the power quality (PQ) indices in the grid by eliminating voltage sensors (grid side) in the overall control. Moreover, presented control method effectively eliminates the DC offset from the input signals and estimates the fundamental element (FE), which is processed to compute the reference signals. The UPQC-PV system comprises two voltage source converters, one connected in a parallel at the point of common coupling for load compensation and the other connected in series via an injecting transformer for voltage compensation. The comparative performance is demonstrated in this work to validate the effectiveness of presented control over state-of-art control algorithms. Moreover, the cost analysis of the presented control is also discussed with the traditional controllers. The UPQC-PV system is simulated in Simulink tool of MATLAB and the performances are analyzed at various dynamic scenarios such as load unbalancing; distorted grid voltages; symmetrical and asymmetrical voltages swell and sag; and change in solar insolation, etc. Experimental results illustrate the superior performance under various operating conditions. The harmonics and magnitudes of load side voltages are restricted as per the IEEE standard 1159. The grid currents and load voltages are well sinusoidal with their total harmonic distortions in the permissible range state in the IEEE standard 519.