Fuzzy based unified power quality conditioner for power quality improvement

Non-linear loads are normally affected by power quality (PQ) problems. Harmonic currents create system resonance, capacitor overloading, decrease in efficiency. Voltage sags are commonly occurring power quality problems in electrical systems. The unified power quality conditioner (UPQC) is one of the FACTS controllers used for mitigating the effect of voltage sags. The series compensator in the UPQC is for quadrature type of voltage injection. So that at steady state the series compensator never consumes active power. The proposed method introduces a low power rating series compensator that injects the voltage which perfectly compensate the power quality problem of the system. The addition of fuzzy logic controller with the conventional UPQC reduces the voltage sag levels in the output voltage and also improves the power factor. The control circuit is designed using fuzzy logic controller and simulated using MATLAB/SIMULINK.