Design And Implementation Of Active Power Filter Based On DSP

With the rapid development of power electronics technology in the 21 st century,more and more power equipment is being put into factories and households.Subsequently,the harmonic pollution and three-phase imbalance in the distribution network have become more and more serious,and the power quality will decline rapidly,causing loss or even damage to power equipment.Today,with the emergence of Active Power Filters(APF),the problems of harmonic pollution and three-phase unbalance have been effectively managed.However,the device designed by the traditional APF design scheme has the problems of insufficient dynamic performance and insufficient adaptability.In response to this problem,on the basis of the original scheme,a new APF scheme is proposed to replace the original scheme to improve its dynamic performance and adaptability..The specific research contents are as follows:(1)The traditional APF is only suitable for the current with harmonics but not suitable for the power system with both current and voltage containing harmonics.The results show that the APF cannot accurately extract the phase when the voltage contains harmonics.In view of this situation,an improved algorithm of phase-locked loop based on dual coordinate system is proposed.This algorithm can make the APF still accurately extract the phase when the voltage contains harmonics,and at the same time improve the phase detection of the APF under the three-phase unbalance.Speed and precision.(2)Aiming at the problem of insufficient dynamics in the traditional APF scheme,a dynamic harmonic current detection method is designed to replace the ipiq harmonic detection method in the traditional APF scheme.The improved harmonic detection method inherits all the functions of the original detection method,and can also compensate for specific harmonics.Greatly improves the APF’s ability to dynamically manage harmonics.(3)Carry out simulation analysis on the scheme widely used in designing APF at present and the improvement scheme proposed in the article respectively,and use MATLAB tool to analyze the advantages and disadvantages of the two at the simulation level.Mainly in: phase-locked loop phaselocking speed and accuracy,harmonic detection dynamics,current tracking accuracy.Finally,it is verified that the proposed scheme has improved phase-locking accuracy and dynamics compared with the traditional scheme.This improvement makes APF control harmonics faster,control three-phase unbalance more accurately,and has wider adaptability.After verifying the theoretical feasibility of the proposed scheme,an APF prototype was designed,using the power quality standard issued by my country and the IEEE/ANSI Standard 519 standard issued by IEC as the test requirements.The results show that under the designed APF,the harmonic distortion rate of the connected power system is reduced from 33.68% to 3.32%,and the power factor is increased from 73.65% to 92.50%,which is in line with the set expectations.