Research On Selective Harmonic Three-phase Four-Wire Active Power Filter

In recent years,a large number of power electronic devices are applied in electronic power system,such as factory power supply,residential and urban power supply system and so on.They are improving the quality of life and industrial production also bring harmonic pollution,which can not be ignored.Active power filter is an important device for harmonic suppression and reactive power compensation,so active power filter for harmonic compensation and governance has a good application prospect in low voltage distribution network.For three-phase four-wire system,the number of certain harmonic occupies considerable proportion in the total harmonic component,and the damage is quite serious.Selective harmonic three-phase four-wire system active power filter can compensate full harmonic and only major harmonics.At the same time,we can use several smaller capacity in parallel active power filter.Each system separately compensate certain times haimonic,in order to avoid the use of large capacity of active power filter.Therefore selective harmonic three-phase four-wire system active power filter has general applicability and practical value.In this paper,based on the analysis of three kinds of active power filter topology in the three-phase four-wire system,we use three single-phase active power filter system to solve the problem of harmonic compensation.Focus on harmonic detection method based on instantaneous reactive power theory and the proportion of quasi resonant compensating current control strategy.First of all,the harmonic current detection methods and control methods are analyzed in theory.Through the research of traditional three-phase system harmonic detection method,which is based on instantaneous reactive power theory,we put forward the single-phase system harmonic detection method,as well as advance the single harmonic detection method of single-phase system,which is also based on instantaneous reactive power theory.DC side voltage control and quasi resonant control of compensation cunrrent are used to realize the compensation current no difference tracking.The single polarity SPWM modulation method is used to improve the harmonic compensation performance.Secondly,simulation software PSIM is used to build a simulation system,where the harmonic detection method and control method were simulated.Finally,through building a complete three-phase four-wire active power filter experimental system,carry out the detection and compensation of the harmonic current.Experimental results demonstrate the detection and control methods used in this paper is feasible and correct.