Research On Harmonic Suppression Of Three - Phase Shunt Active Power Filter Based On Instantaneous Reactive Power Theory

With the development of power electronic technology, a variety of nonlinear device are being used more widely,which seriously caused the problem of harmonic pollution and reduced the quality of power grid. Active Power Filter is recognized as the most effective means to suppress the harmonic of power grid among a series of harmonic compensation device. Therefore, the research of key technology has become hotspot. Firstly, this paper describes the present research on harmonic and active power filter. And then it proposes the research program on the basis of previous studies.Secondly, basic classification of the active power filter were studied on three-phase three wire system were studied in detail, and a mathematical model was set up, and in the theory of main circuit of the active power filter using voltage feedforward decoupling is the ip-iq decoupling algorithm.Again,this paper design of the compensation capacity of existing equipment, calculates the main parameters of affecting the compensation system. It contains DC voltage, DC capacitor, AC side inductance.Then, it studies and contrasts the seven detection methods based on this theory, and then chooses the ip-iq current detection method based on the theory of instantaneous reactive power theory, and chooses the low-pass filter.Because of traditional control methods can’t solve the problem of time delay cause by digital control process, the harmonic decoupling method has been proposed. This paper mainly researched the realization of decoupling control strategy in Active Power Filter.The improved detection not only has better detection effect on real-time but also can detect the harmonic current better. Then, it compares current control method, and selects the hysteresis of comparative method as the current control method. In this paper, It further compares the control effect on charging DC side capacitor using the PID condition of traditional ip-iq method and ip-iq decomposition method, experimental results show that the ip-iq decoupling method has good real-time performance.Finally, it builds the system simulation diagram by MATLAB/SIMULINK, and studies on the three-phase three-wire system. Respectively, it studies simulation study on some situations, which contains Inductive power grid and nonlinear load, standard power grid and nonlinear load, standard power grid and variable load,traditional ip-iq detecting method and decoupling ip-iq detecting method. The simulation result shows that the design can inhibit the harmonic well, and the design meets the requirement.Finally, according to the laboratory existing 7.5kW permanent magnet direct drive wind power generation power grid local experiments, the results show that the design scheme is reasonable and feasible.