| With the proliferation of nonlinear loads in grid, more and more harmonic current has increased. This causes the deterioration of the power quality. Therefore, with its predominant compensate performance, the active power filter(APF) is considered as the most effective method to eliminate the serious "power pollution" at present. The shunt active power filter plays the most important role in the past or future.Firstly, the dissertation introduces the concept, principle and development trends of APF in detail and analyses the classification of APF.This dissertation has presented the system structure and mathematic model of three-phase three-wire shunt APF.Furthermore, deeply analyzing the ip-iq harmonics current detecting method based on instantaneous reactive power theory, through the use of analog-digital filter combined can overcome the measurement error that is made by anti-mix analog filter with non-linearity in the pass-band. Adding the compensatory angle can reduce the infection of the digital controller's delay time. Simulation results prove the correctness of the algorithm.Base on deeply analyzing the advantages and limitations of the adaptive fuzzy PI control and the repetitive control in APF respectively, the dissertation adopted adaptive fuzzy PI-repetitive combined control to correct the output current waveform of the APF. The repetitive control is used to improve the steady state characteristic of the control system; The adaptive fuzzy PI control is used to improve the dynamic characteristic of the control system; The dissertation adopted PI control to makes DC side voltage of APF stability at the standard. This dissertation emphasizes on the design process of links in repetitive control, simulation in matlab show that the proposed method is valid and feasible.Finally, the control system which is based on TI digital signal processor (DSP) TMS320F2812 is designed, including the hardware circuit structures and the software structures. |
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