Control of UPQC through Observer based System Integrated with Frequency Adaptive Loop and optimized PI Gains

Abstract

This paper addresses the functions of unified power quality controller (UPQC) during Power quality (PQ) issues on the distribution networks. The poor power quality is mainly a cause of harmonic currents, lower power factor, variation in supply voltage, etc. A UPQC is a Custom Power Devices (CPD) that reduces the voltage and current related PQ problems in the power distribution system. The proposed control algorithm for UPQC is a frequency adaptive loop (FAL) on first transformed module (FTM) of the observer method. As in most Phase Lock Loop (PLL) algorithms, where the transformation of variables into a synchronous reference frame is required to get phase angle detection. Nevertheless, in the case of FTM based FAL, it does not require conversion to estimate phase angle. The angular frequency used to detect unknown estimated parameters and positive-negative elements of the signal under any PQ problems. Another side, the optimal tuned value of proportional-integral (PI) gains are calculated using Firefly algorithm. So, the PI-controller gains are improving dynamic execution of UPQC Controller. The results are captured using MATLAB-Simulink and validated in real time to support the functionality of the UPQC.