Single Phase UPQC Integrated with Photovoltaic System without DC-Link Capacitor Using Fuzzy Logic Controller for Power Quality Improvement

Abstract

This paper proposed a single-phase unified power quality conditioner (UPQC) integrated by a photovoltaic (PV) array using a fuzzy logic controller (FLC) in a single-phase low-voltage 220 V-50 Hz distribution system to improve the power quality. The PV array consists of several PV panels with a maximum power of 12 kW. There are two proposed circuit configuration models, i.e. UPQC-PV connected to a linear load (LL) and UPQC-PV connected to a non-linear load (NLL). The proposed single-phase UPQC-PV is without using a DC link capacitor. The PV system is then used as a DC voltage source which functions to supply load active power when the source is interrupted and simultaneously replaces the role of the DC link capacitor to keep the PV output voltage and also the DC link connected to UPQC so that the value remains constant. FLC is used to overcome the weakness of the proportional-integral (PI) control method in determining the optimum parameters of the proportional constant and integral constant. There are six disturbances simulations i.e. Operating Mode (OPM) 1 (S-Sag-LL), OPM 2 (S-Swell-LL), OPM 3 (S-Inter-LL), OPM 4 (S-Sag-NLL), OPM 5 (S-Swell-NLL), and OPM 6 (S-Inter-NLL). In the single-phase system using UPQC-PV configuration, OPM 6 disturbance with FLC control is able to result in the lowest load voltage change. In the same configuration as the OPM 1 to OPM 6 disturbances, the FLC is able to produce a lower load voltage total harmonics distortion (THD) and source current THD than the PI control, and has complied with IEEE-519 limits. In the same configuration as PI/FLC control, OPM 4, OPM 5, and OPM 6 disturbances are able to absorb greater load active power than systems with OPM 1, OPM 2, and OPM 3 disturbances