Research On Detecting And Control Method Of Unified Power Quality Controller

The plenty of harmonics produced by nonlinear, imbalance and impact load can make the waveform of current and voltage in power system produce serious distortion, which produce some power quality problems. The safety of power system and the quality of power supply has been threatened. The idea which restrain power quality from waveform of current and voltage become development tendency.Unified Power Quality Controller (UPQC) is one the most up-to-date development trends of custom power and an important represent in the active power filter family. It combines the advantages of both the series active filter and the parallel active filter, which provides comprehensive power quality compensations. It can compensate voltage, current and promote power quality.At first, the topology and the function of UPQC are explained in the thesis. Then, the detection method and the control strategy, which are the important parts affecting the compensation effect of the UPQC, are discussed and investigated in detail in the thesis. In the basis of APF detecting method, the thesis deduces the detecting method of voltage and current based on generalized instantaneous reactive power theory. This paper also shows the detecting method of voltage and current based on Park transformation is correct in theory. This paper uses Space Vector Pulse Width Modulation (SVPWM) as control method of UPQC inverter. The basic principle of SVPWM is described in detail in thesis. Simulation results given in the thesis verify the correctness of the detection method of voltage and current and the control strategy proposed in the thesis.The studies presented in this thesis is useful to Power Grid Companies to improve electric quality and is also useful to power equipment manufactures to develop their products.