Study Of The Unified Power Quality Controller

With the wide application of the nonlinear loads and all kinds of power electronics equipment, the power quality issues become more severe, so the study on power quality has aroused more and more attention. The unified power quality controller (UPQC) with double converter structure has been proposeed in this paper, which can effectively solve multiple power quality problems either from the load or from the line side.Firstly the research background and signification of the UPQC is introduced, ane the system configuration and basic operation principles are discussed. Then, several kinds of detecting methods of compensation signals are discussed, and a kind of detecting method based on instantaneous reactive power theory is presented for the UPQC. The theoretic analyses and the simulation result examine the feasibility and validity of this detecting method. Subsequently, the two tracing pulse wide modulation control approaches which have been widely used are discussed , and the timer-control hysteresis pulse wide modulation control method is fit on the UPQC better. Moreover, the circuit parameters of the UPQC, series active power filter (APF) and shunt APF, which have great influence on the compensation effectiveness are studied. At last, based on the theoretical analysis, the simulation models of the UPQC, the series APF and the shunt APF, are built up with SimPowerSystems Blockset of MATLAB/SIMULINK. The simulation results show that the UPQC can solve multiple power quality problems in power systems, and its compensation function is better than other compensation equipments.