Enhancement of Power Quality using Fast Acting Unified Power Quality Conditioner (UPQC)

Abstract

The Unified Power Quality Conditioner (UPQC) is the most flexible solution for all power quality problems. The UPQC is one of the APF family members where shunt and series APF functionalities are integrated together to achieve superior control over several power quality problems simultaneously. Reference signal extraction is the most important part of any control. Feedback control requires the minimum information about the process also the corrective action is taken when the control variable is changed but it has some drawbacks that it does not provide any predictive action for any known disturbance. The proposed control technique uses feed forward plus feedback control with synchronously rotating reference frame based reference signal extraction that not only measures the disturbances (voltage sag here) but also take corrective action to compensate for the same before they actually disturb the system. The applications of feed forward control along with the feedback control are able to compensate for the measured disturbance with the desired speed of response that enables faster restoration of voltage at load end. The suggested method is implemented by simulation in MATLAB/SIMULINK to demonstrate the improvement in response time.