A New Control Method for Improving the Performance of UPQC Under Unbalanced and Distortional load Conditions

This paper presents a new control method for a three-phase four-wire Unified Power Quality Conditioner (UPQC), in order to deal with the problems of power quality under distortional and unbalanced load conditions. The proposed control approach is the combination of instantaneous power theory and Synchronous Reference Frame (SRF) theory which is optimized by using a self tuning filter (STF) and without using load or filter currents measurement. In this approach, load and source voltages are used to generate the reference voltages of series active power filter (APF) and source currents are used to generate the reference currents of shunt APF. Therefore, the number of current measurements is reduced and system performance is improved. The performance of proposed control system is tested for cases of power factor correction, reducing source neutral current, load balancing and reducing current and voltage harmonics in a three-phase four-wire system for distortional and unbalanced loads. Results obtained by MATLAB/SIMULINK software show the effectiveness of proposed control technique in comparison to the conventional p-q method.

Keywords:

Power quality , Unified Power Quality Conditioner (UPQC) , Voltage harmonic mitigation , Current harmonic mitigation , Source neutral current mitigation