Active Power Filter Control Based On Selective Harmonic Elimination Method

More and more attentions have been paid to" power clean "for the serious "power pollution "problem. Active power filter overcomes the drawbacks of passive power filter and has many multifunctions, such as harmonic compensation, reactive power compensation, flicker/imbalance compensaiton and voltage regulation, so it has been considered as one of the most effective methods to suppress the serious "Power Pollution" problem. In this paper, a study on the selected harmonic elimination control algorithm of active power filter is to provide a kind of effective control scheme, analysis and design methods for active power filter.First of all , the cascaded multilevel inverter with direct current power supply is adopted in this paper in order to reduce the harmonic content and realize the modularization. The feasibility is verified by corresponding simulation.Secondly, according to the low detection precision, slow response and poor effect of harmonic compensation of the harmonic current detection algorithm, the paper introduces p-q algorithm and ip-iq algorithm based on the instantaneous reactive power theory, and the simulation experiment study on the detection of random and reactive harmonic in three-phase circuit is given.Thirdly, selected harmonic elimination control algorithm is introduced by studing Curve Fitting Technique (CFT) and solving nonlinear equations. Moreover selected harmonic elimination control algorithm based on CFT is presented. The rapid response and satisfactory control precision are obtained by using this control algorithm. The feasibility is verified by simulation results.Finally, the paper constructs a simulation model of shunt hybrid active power filter based on MATLAB/Simulink selected harmonic elimination. It can well detect the harmonic by the simulation experiment. Selected harmonic elimination has many virtues such as good dynamic response, much higher detection precision and quick compensation to harmonic current. It can reach the goal to improve and optimize the quality of the electricity networks.