The Research Of Parallel Connection Active Power Filter

Due to the wide use of power electronic equipments in industrial applications, the harmonic current that produced pours into electrical network. Harmonic problems have become the important factor that affects the quality of power supply. Active power flither (APF) is a new power electronic device which can effectively compensate harmonic and reactive current of network. APF have gradually been recognized as a feasible solution to the problems created by nonlinear loads.The paper discusses the basic principle of active power filter and the parallel active power filter's configuration overall, then discusses harmonics detecting methods,controlling methods,designing the main circuit and other respects in detail. Based on analysis the characteristic and disadvantage of traditional methods: p,q harmonics detecting methods and i_p,i_q harmonics detecting methods, ameliorate the i_p,i_q harmonics detecting method, improve the capability of exact and real-time;in controlling part, analyse the characteristic and disadvantage of two traditional methods: triangular wave compare control method and hysteresis current control method, bring forward a nerve network controlling method, this method has the hight compensation precision and algorithm and need not analog control circuit such as hysteresis compare circuit, so it is very convenient to be accomplished with digital merhod, in addition, this method cut down the swich frequency and decrease the wastage of APF.In order to validate the new methods, the three-phase shunt voltage parallel active power filter was simulated in Matlab/Simulink by using SimPowerSystem Blockset. The simulation results show that the new parallel active power filter based on new methods are correct and APF can eliminate harmonic current effectively.