Research And Realization Of Shunt Active Power Filter

With the rapid development of power electrical technology, large scale power electrical devices connected to grid which makes the pollution problem of power grid becomes more and more serious. Active Power Filter (APF) is a power electrical device which can finish the hommonic current treatment and reactive power compensation simultaneously. Because of its superior performance of compensation, APF has become a focal point of research in the power electronics technology. And shunt active power filter has been the research focus of APF. Therefore, the key techniques of shunt APF were deeply researched in this thesis: hommonic current detection and current track technology, furthermore, simulational and experimentional research was also given in this paper.First of all, in hommonic current detection aspect, the instantaneous reactive power theory based on current (ip-iq method) was deeply researched and analysed in this paper. And the instruction current detected by ip-iq method is inexact when the three-phase voltage is unbalanced. Using symmetrical component method, this paper improved ip-iq method and proved that the improved ip-iq method could solve the problem of ip-iq method in theory.Secondly, in current track technology aspect, for the static error and the poor dynamic of space vector pulse width modulation (SVPWM) in the application, this paper proposed a close-loop space vector pulse width modulation method based on PID method, and designed a current tracking controller of shunt APF which made the output current of APF could track the commend current rapidly and exactly.Thirdly, in the enviroment of MATLAB/Simulink, the improved ip-iq method, the close-loop SVPWM based on PID and the APF system were simulated in this paper. According to the simulation results, the improvement program of the key technology used in shunt APF could solve the problems of the original theory and the principle proposed by this paper has a certain feasibility and practicality. Finally, the hardware and software of the shunt APF system were designed in this paper, and experimental research was conducted on the APF system. The experimental results showed that the improvement program of the key technology could be used in shunt APF and has a certain practicality.