An Effective Control Technique to Implement an IUPQC Design for Sensitive Loads in a Hybrid Solar PV-Grid Connection

Abstract

The recent innovation in power electronic application in the electrical power system (EPS) has given birth to an Improved Unified Power Quality Conditioner (IUPQC) that positively impacts the electrical power system (EPS). The previously available mitigation approaches with the application IUPQC are monotonous and are major designs for a particular power quality (PQ) issue which does not take care of the degree of impart. This paper presents an effective control architecture of an IUPQC design for sensitive loads in hybrid Photovoltaic Solar (PV) connected grid, concentrating on the voltage demand of loads that respond to slight changes. The objective of this work is to design a flexible controller that can respond to the different degrees of PQ challenges concerning voltage, variable load, and solar irradiation. It has combined the merits of an IUPQC and grid-integrated PV source. Effective controllers for Voltage Source Inverter (VSI) connected in series and Current Source Inverter (CSI) connected in shunt compensators of the UPQC are implemented to increase device strength for different voltage and current distortions. The series compensator was controlled using an enhanced Synchronous Reference Frame (SRF) technique based on adaptive notch filters. An Adaptive Logarithmic Absolute Algorithm (ALAL) was deployed for the parallel section of the proposed approach. The Mean Turning Filter (MTF) was used as a replacement for a low pass filter (LPF) for direct current node voltage management, leaving high and low-frequency ripples unaffected. To maintain a constant current on the grid side during grid disturbances, a feed-forward element has been introduced to the shunt CSI controller. Under various network situations, such as under-voltage, over-voltage, voltage distortion, harmonics, rapid load changes, and fluctuation in solar power, the control system performance is better as confirmed by experimental validation. Finally, it is observed that the voltage profile of 0.984 p.u. due to application control falling within the permissible limits. The proposed controllers are tested in the MATLAB Simulink on a developed distribution system model and validated experimental prototype.