Research On Resonance Detecting And Damping With SAPF

With the development of social industry, stable and efficient operation of precision instruments and equipments require highly reliable power. Distribution system is closely related with people's lives. The increasing use of non-linear loads results in a large amount of harmonic currents flowing into the distribution network in recent years, which leads to the distortion in the point of common coupling(PCC) voltage and weakens the power quality in the distribution network. At the same time, the use of shunt capacitors will also lead to the partial or total resonance, making the harmonic problem worse. As a high-efficient harmonic compensation device, shunt active power filter is being widely used in the field of power quality. The main purpose of this paper is to use active power filter to detect the resonant frequency of the system and to research the control strategy of harmonic compensation and resonance damping, making the power distribution system to meet the quality standards.This paper firstly introduces the generation and the hazard of harmonic currents as well as domestic and international power quality standards. The development of active power filter is reviewed and the current research work is being introduced. In addition, this paper points out that detecting the resonant frequency and researching harmonic compensation and resonance damping hybrid control strategy based on active power filter is really valuable.Then the three-phase three-wire active power filter structure and the mathematical model are introduced. PI plus repetitive hybrid control strategy is studied to achieve harmonic current static error tracking, whose effectiveness is verified by simulation. The main factors that affect the resonant frequency of the resonant system are studied. Several methods to detect the resonant frequency of the resonant system are listed and compared. The harmonic current injection method is chosen for depth theoretical analysis, whose effectiveness is verified by simulation.The resonance mechanism and physical meaning of the resonance system is researched. The resonance damping hybrid control strategy based on the voltage of PCC is also purposed, whose effectiveness is verified by simulation. In addition, some new hybrid control strategies are purposed based on the original control strategy, whose effectiveness is also verified by simulation.Finally, the theory presented in this paper is verified by experiment. Experiments show that the harmonic current injection method is able to detect the resonant frequency quickly and accurately; the hybrid control strategy of harmonic compensation and resonance damping used in this paper is also proved that it can suppress harmonic resonance effectively. I hope that this article will broaden the of applications area and facilitate the promotion of active power filter.