Three-phase Three-wire Parallel Active Power Filter Control Research

The active power filter may compensate for the harmonic current that isproduced by the load, which has the vital significance to the national economydevelopment. In this thesis, the design of LCL filter, the parameters of the controllerdesign, the control algorithm and no harmonic detection algorithm in the activepower filter are discussed.The mathematical model of Three-phase three-wire parallel active power filteris established under the static coordinate system, and through the dq rotation, themathematical model of three-phase three-wire parallel active power filter is deducedunder the dq reference frame, which is the theoretical basis for the design of thecontroller. At the same time, the LCL filter theory and the LCL filter parameters onthe filtering performance are analyzed. A design method of the LCL filter isproposed and the theoretical derivation is given. Finally, the superiority of thedesigned LCL filter is proved by comparing with the L-type filters.The design of the traditional double closed loop controller parameter isdiscussed, and the current loop to understand coupling control and voltagefeed-forward control. As the PI control can’t achieve no steady-state error when tocompensate the harmonic signal, the PIS control strategy is proposed. In order tooffset control object pole, an improved algorithm PI-VPI is put forward on the basisof PIS control strategy. Finally the simulation confirmation to three kind of controlstrategies is done, and the PI-VPI effect is proved to best by the theory and thesimulation result.Theoretical derivation of non-harmonic detection program and the relationshipbetween the shunt active power filter without harmonic detection and traditionalactive power filter are given. Finally, the simulation results prove that the shuntactive power filter without harmonic detection and traditional active power filter inthe compensation effect are the same. But the shunt active power filter withoutharmonic detection can reduce hardware costs, and eliminates harmonic detectionlink.This article carried on the three phase three wire active power filter softwareprogram design and experimental debugging, the load is three-phase uncontrolledrectifier bridge, which verifies the theory proposed in this thesis.