Research On Active Power Filter Based On T-S Fuzzy Control

With the rapid development of industrial economy and the power electronics in our contry, lots of nonlinear loads, such as power supplies and rectifier equipments, are widely used in the power system. Those nonlinear loads bring convenience to power transformation, but at the same time, they draw nonsinusoidal currents from ac mains and cause reactive power burden and excessive neutral current.At the result they bring serious damage to the safety of power system and power equipment. The Active Power Filter (APF) is a kind of device which can reduce the harmonic currents and reactive current in the power grid. Developping for about 50 years, the active power filter has achieved extensive application in the power system. In recent years, advanced control theory for APF becomes an important research direction. Takagi-Sugeno (T-S) fuzzy control as a kind of advanced control strategy is paied more and more attention in the control of nonliear system. In this paper, the application of T-S fuzzy control in APF was made an intensive study and experiment.Firstly, the basic principle of active power filter is studied, and the key techniques related to shut APF are also anasysied. Taking three-phase and three-wire shut APF as an example, this paper pointed out that it is the key to control the dc capacitor voltage. The basic principle of T-S fuzzy control strategy is introduced and design method of fuzzy controller is also discussed.Secendly, the mathematical model and the T-S fuzzy model of APF were built by using parallel distributed compensation method (PDC).The stability of the fuzzy control sysem was analyzed based on Lyapunov approach. Two theorems were obtained to keep the closed-loop stabily and to derive the feed back gains.The system based on fuzzy control method is simulated with Matlab,and the simulation results are given to illustrate the system performace of the proposed T-S fuzzy control. All of research provided necessary basis for the design of APF.Finally, the control system based on DSP2407 was designed, meanwhile the software and hardware were introduced in detail. The experiment was done to show the performance of the APF. The data of the experiments and analysis of waveform verified the feasibility of the design. So, the superiority of fuzzy control strategy given is well approved by the result of experiments.The APF based on the control strategy proposed in this paper has a good application prospects.