Compensation Minimum Harmonic Current Detection Method And Its Active Power Filter Realization

With the rapid development of the power electronic technology, the AC/DC converter equipments have been applied widely in industrial enterprise. These nonlinear equipments infuse much harmonic to power system in the process of transformation, absorb and exchange of electric energy and cause the voltage and current disturbance. The harm and influence to natural run of power quality come into being for the fall power quality.The basic conception, the cause and main harm of harmonic are introduced in this paper firstly. The main character of power network and parameter of charge devices are described. On the basis of these, the development of harmonic elimination technique around the world is analyzed. A general description of the principle and structure of Active Power Filter are given in the paper.Then, the harmonic detecting method based on theory of instantaneous reactive power is researched as emphases, and a new single-phase current detecting theory and approach based on the least compensation current are presented and made out systematically. Using a analog hardware circuit to realize the adjustment is simulated and designed according as it, and a according single-phase circuit Active Power Filter is made. The results not only indicate that the APF based on the harmonic detecting method can produce a better fast dynamic response but also prove the APF can complete efficiently the compensation of the harmonic current.On the basis of simulation, a digital realization scheme of the least compensation method applied to DSP chip as a CPU is brought forward. Furthermore, hardware and software of the single-phase APF based DSP for testing are designed and adjusted. The experiment results indicate that the APF can detect and eliminate harmonic current caused by nonlinear load accurately and effectively.