| Active Power Filter is a method of harmonic suppression and reactive power compensation. From 80th of 21st century, with high development in power electronic device and its control technique, Active Power Filter is become more and more mature, and it has been put into practice for a long time in foreign countries. Compare with passive filter, Active Power Filter is more controllable and has quick response features, and it can follow and compensate every order harmonic. Besides, it can generate desired reactive power automatically without influence from main system. Active Power Filter has no risk of harmonic amplification. As Active Power Filter are put into practice, it will bring tremendous economic benefit and social benefit to our country.This paper first introduced the theory of how Active Power Filter compensate harmonic in power system, and summarized the classification and feature of Active Power Filter. Then a description about development in Active Power Filter domestic and overseas was given and the meaning of research in Active Power Filter was analyzed. Third, a modern research method of Active Power Filter was put forward, and then I use it as research method in this paper.Aiming to Active Power Filters In Three-Phase Four-Wire System, the mathematic model of shunt Three-phase Four-Wire System active power filter are present. With this mathematic model, a control strategy based on sliding mode control is developed. According to the reaching law, it can eliminate the chattering of sliding mode control. In order to detect designated order harmonic current, using Wavelet packet transform to detect harmonic current is researched. The simulation results from MATLAB show that this Active Power Filter has good performance on suppressing the harmonic in power systems.The work that I did in my paper has good meaning for improving the accuracy and stability of Active Power Filter, at the same time it can improve application of sliding mode control in power industry. |
PDF Full Text Request