Performance Improvement for a Series Active Voltage Quality Regulator with Source Voltage Feed-forward and Load Voltage Feed-back Control

The series active voltage quality regulator is a new power electronic equipment designed to mitigate the voltage disturbance in forms of voltage swell, voltage sag, distorted voltage waveforms, harmonics, transient interruption, frequency deviation on sensitive loads. Performance of the series active voltage quality regulator in improving the quality of power supply is examined. It is shown that the existing open-loop control strategy used in the series active voltage quality regulator to regulate load voltage can produce poorly damped response due to the presence of the switching harmonic filter in the regulator. Also, the load voltage feedback method called closed-loop control is still inadequate because the bad load regulating characteristic and the poor dynamic response. In order to improve the performance, a composite control method that combined feed-forward of source voltage and feed-back of load voltage is proposed in this paper. Furthermore, this paper firstly presents two criterions that should be satisfied when the load voltage is properly tracking the reference voltage for active voltage quality regulator. Aimed at these two criterions, three control methods are comparative analyzed in detail. Through comparative analysis, the proposed scheme is verified to be better than the previous methods. At last, the validity and effectiveness of the proposed control scheme are verified by the computer simulation and laboratory experimental results.