Research On The Parallel Hybrid Active Power Filter Based On The Instantaneous Reactive Power Theory

Large applications of power electronic devices have made the harmonicwaveform impact the grid more and more serious. In recent years, as the rapiddevelopment of power electronics technology, compensating waveform by usingactive power filter has become the main development direction, therefore studyingparallel hybrid active filter based on instantaneous reactive power theory has greatsignificance.Firstly this paper has a detailed study on the cause of harmonic wave and itsharm as well as the status of the study on harmonic wave at home and abroad, andmade a detailed analysis about the type of active power filter. This paper has anemphasis research on the harmonic wave detection technology based oninstantaneous reactive power theory. This paper also analyzed the impact that thefilter parameters of different types of low-pass filter such as Butterworth, ChebychevI, Chebychev Ⅱ on the results of harmonic detection, and the filter parametersincluded the order of the filter, the cutoff frequency, etc. The simulation results showthat low pass filter when its type is Butterworth and its cut-off frequency is20HZand its order is second, has rapid dynamic response and high detection accuracy butis of low cost when this filter was used in the harmonic detection circuit which isrealized by using instantaneous reactive power theory.After a further study of the low-pass filter which had effect on harmonic currentdetection, this paper proposed an adaptive harmonic current detection method. Thisalgorithm used a variable step size minimum mean square error adaptive filter as alow-pass filter in the detection circuit, and through theoretical analysis andsimulation verification, this algorithm could detect the harmonic current command signal much faster and had better steady detection accuracy than traditionalalgorithm.The parallel hybrid active power filter which used capacitance injectedcompensation current method, could make compensation current of the active filtercoupled to the grid, in this way, it could reduce the capacity of active filter device.This paper did simulation study of active power filter which used capacitanceinjected compensation current method by using MATLAB/SIMULINKSimPowerSystems, and also built a simulation model including the power part, theharmonic detection part, the passive filter section, and the command signal part. Thesimulation results show that the capacitive injection parallel hybrid active powerfilter can effectively suppress harmonic currents produced by nonlinear load.