Research On The Simulation Of Harmonic Current Detection And Compensation Control Technology Of Shunt Active Power Filter

In recent year，with the widespread use of a large number of the power electronicdevices, harmonic pollution becomes more and more serious, and modern electricalequipment appeals higher demand for power quality, people has been paying moreattention to the problem of harmonic pollution. Active Power Filter is the equipmentused to clearing up harmonics dynamically, which has a large number of advantagesby comparison to Passive Power Filter. It has been a hot research field in the harmoniccontrol.With the three-phase and three-wire parallel active power filter as the researchobject, this article deeply studied the algorithm of harmonic detection and controlstrategy for current compensation. Firstly, the p-q、 ip-iqmethod based onInstantaneous Reactive Power Theories have a comparative analysis. As the ip-iqdetection method is simpler than p-q detection circuit and the advantages of testingresults, take the ip-iqtest simulation of harmonic detection method in MATLAB/Simulink to build the module, have verified the accuracy of the method. Then, thethesis proposes a new method for online detection of harmonic current based onWavelet analysis. By using a combination of the principle of wavelet analysis and thesliding time window, this new method eliminates the low pass filter. At the same time,the algorithm steps are designed and the online detection function is achieved byusing of the S-funciton function. The simulation model has been established, and theresults show that the new method overcomes the drawback of ip-iqdetection methodwhich performs not well in real-time as it’s using of low-pass filter. The new methodsimplifies the model structure as well, having good detection effectiveness andadvantages. Secondly, the simulation model of the strategy of compensation currentbased on the hysteresis control and the triangular wave control are established, theresults show that the hysteresis comparator detection have higher accuracy than thetriangular wave comparison, but a little bit poor at the dynamic followingperformance. Then the effectiveness of the two methods are verified that a PIregulator is used to control the DC side voltage fluctuations and parallel startupresistor is used to reduce the impact current at the instant of SAPF into the electricline by simulation. Finally, According to the mathematical model of APF andparameter selection related in this paper, the overall simulation model of thethree-phase and three-wire parallel active power filter by Simulink module of matlab is founded. The harmonic detection algorithm makes analysis and comparison of theip-iqdetection method based on instantaneous reactive power and harmonic detectionmethod based on wavelet analysis, meanwhile, the strategy of compensation trackingcontrol choose the hysteresis mode, the simulation results show that the proposeddetection algorithm have the higher accuracy and better real-time dynamicperformace.