Research Of Shunt Active Power Filter

Active Power Filter (APF) is considered as one of the most effective solution to improve power pollution. It can compensate harmonic of which frequency and amplitude is variable and the compensating characteristic is free of infection of the impedance in the electrical network. The good filter character of APF can satify the needs of compensation, so it has been widely researched and developed in the recent years. This dissertation aims at the problem of harmonic which exists widely in industry consumers, and forcus on the research of three phases shunt active power filter.First, the dissertation introduces the background, present situation and development trends of APF, the principle of APF, and represents the harmonic detection and control strategies which based on instantaneous reactive power theory in detail.Furthermore, this dissertation constructes the averaged switch models under ABC stationary reference frame and pq rotation reference frame with the cycle by cycle switching operator and designed a soft start method for APF. The result of simulation by Matlab/Simulink can show that, it can eliminate the harmonic currents effectively without the phenomenon of over-voltage and over-current.Finally, a shunt active power filter device which is based on TI digital signal processor (DSP) TMS320F2812 is designed and completed, including the hardware circuit structures and the whole algorithm procedure of harmonic detection and compensation, it focus on the design of butterworth IIR digital low pass filter which applied to the harmonic detection. The experimental results under low-power conditions show that the device has a good performance of real-time detection and accurate compensation.