Design Of The Low-Pass-Filter For Harmonic Detecting In Active Power Filter

With the widely application of power electronics technologies, nowadays the electrical harmonic pollution becomes a serious problem. It decreases the quality of electric power system, which becomes a difficulty problem to be resolved. Whereas; Active Power Filter (APF) is an advanced power electronic device which can be compensate the harmonic pollution. Compared with several traditional compensating measures, APF has many advantages and favorable aspects.Harmonic current detection technology is one of the most critical technologies of APF. The development of harmonic current detection technology directly effects the development of APF technology directly. It is very significant to improve the property of APF with the harmonic current detection technology. The technology of harmonic current detecting has been widely applied in real-time detection of harmonic current in APF since it was proposed in 1980s.This paper researches on the harmonic current detection algorithm based on the theory of instantaneous reactive power. The emphasis is the influence on harmonic current detection by different types of low-pass digital filters. Based on the Band-Edge-Selectivity, an optimized design of low-pass detecting filter is proposed. The results of simulation and experiment prove that the design is correct and effective.