Research Of Shunt Active Power Filter Based On Compound Control

With the electrification level improves continually, all kinds of powerelectronic devices widely used in production and living，which causes seriousinfluence to power network, the effective governance of the harmonic becamethe subject of much attention. Active power filter for compensation of highprecision, good dynamic performance, and the advantages of small affected bygrid system parameters change, become the important tool to solve the problemof harmonic and reactive power grid.The concrete working method of active power filter is in the power grid incontrast to the harmonic current compensation current, realize the grid currenttends to sine wave, the compensation performance mainly depends on when thesteady state compensation precision and response speed of the dynamicadjustment process. For the study of the active filter consists of the followingwork:First, a-b-c three-phase three-wire system parallel three-phase static systemmodel, the mathematical model of APF, after coordinate transformationestablished d-q mathematical model of the synchronous rotating coordinatesystem and the decoupling control, which provide the basis for the design ofcurrent loop and decoupling control.Second, use of the extraction of harmonic method based on instantaneousreactive poweri p iqtheory, were analyzed and three-phase digital phase lockedloop was designed, so that the harmonic detection and current control, deadzone in SVPWM control technology in the corresponding compensation.Third, control strategy on the design of PI controller and repetitive controller respectively, considering the traditional PI control for dc signal onlydo a static tracking, and for the different frequency ac signal superposition ofAPF harmonic signal given tracking effect is poorer. Therefore, this article adoptPI and repetitive control the composite control method of combining bothrepetitive control of high control precision and good robustness of PI control.Through the MATLAB simulation results demonstrate the validity of thetheoretical analysis in this article.Fourth, to meet the requirements of APF system of multi-channelsynchronous data acquisition and real-time compensation requirements, existingin the laboratory of PWM rectifier platform, expand the two pieces of ADS836512channel high speed synchronous sampling circuit design, the main circuit ofAPF inductor and dc side capacitor design.