Unified power quality conditioner: Design, simulation and experimental analysis

Power quality (PQ) problem can be defined as the deviations of the voltage and/or current from the nominal sine wave. PQ problems generally concern with voltage sags/swells and harmonic currents. Custom Power (CP) devices that mitigate these power quality problems have gained more attention in the recent decades. Unified Power Quality Conditioner (UPQC) is one of the CP devices and it mitigates both load current and supply voltage problems, simultaneously.In this study, UPQC and a new topology of UPQC namely OPEN UPQC are designed, modeled and setup experimentally to mitigate voltage sag/swells and harmonic currents. UPQC consists of Dynamic Voltage Restorer (DVR) and Active Power Filter (APF). An improved voltage compensation controller and new sag/swell detection method based on Enhanced Phase Locked Loop (E-PLL) are presented for DVR. Traditional Instantaneous Reactive Power Theory (IRPT) is optimized for APF control algorithm to compensate harmonic load current under unbalanced and distorted supply voltages. Digital Signal Processor based 6 kVA, 230Vline-lineUPQC and OPEN UPQC prototypes have been developed for laboratory tests. UPQC and OPEN UPQC with proposed controller algorithms effectively compensates the sag/swell in supply voltage by keeping the load voltage amplitude at 0.9-1 per unit and eliminates the load current harmonics by keeping supply current at 5%Keyword: Elektrik enerji sistemleri = Electrical energy systems ; Elektrik güç sistemleri = Electric power systems ; Elektriksel analiz = Electrical analysis ; Enerji dağılımı = Energy distribution ; Enerji kalitesi = Energy quality ; Enerji kullanımı = Energy usage