The Development Of Shunt Active Power Filter

With the development of electric-electronic technology, microelectronic technique and modern control theory, active power filter has obtain rapid development, by which the harmonic, reactive and negative sequence current can realize real-time and accurate compensation. At present APF is considered as the most effective method to eliminate the serious "power pollution" and has been widely investigated at the stage of entering industrial application.First the dissertation introduces the background, present situation and development trends of APF and analyses the classification and principle of APF in detail. Basing on deeply analyzing the theory of instantaneous reactive power, detecting method for high frequency harmonic current is presented and the method of pulse width modulation based on unsymmetrical rule sampling is improved instead of the former the method based on symmetric rule sampling. APF can achieve accurate harmonic detection and production of PWM signal in those ways.Furthermore, the models of every parts of the shunt APF are built respectively. And a fuzzy PID controller is designed to control DC voltage and achieves better performance than that of the conventional PID. The simulation results indicate that The APF can eliminate harmonic current and has good dynamic compensation characteristics, which verify the correctness and feasibility of the theoretical analysis.In practical applications, a shunt active power filter prototype based on TI digital signal processor (DSP) TMS320F2812 is designed, including the hardware circuit structures and the package of harmonic detection and compensation algorithm procedure. The experimental results show that the device has a good performance with real-time detection and accurate compensation.