Research On The Harmonics Detecting Technique Of Active Power Filter Based On DSP

Along with the widely using of power electronics equipments and non-linear loads, the harmonic distortion of voltage and current has polluted power quality seriously. Besides, the low power factor also can affect the power quality. At present, the harmonic problem has become the critical task so as to ensure a high level of power quality, and a lot of attention has been paid to harmonic problem.Active power filter is one of the most effective approaches for suppressing the harmonic at present. Active power filter mainly consists of two parts, the first is current operation circuit, and the second is compensation current circuit. This thesis lays emphasis on the research of part one, and deeply analyzing how to accurately detect the harmonic component.Based on the harmonic problem, this thesis explains the relevant concepts of harmonic, producing of harmonic and the harm of harmonic. This thesis introduces two methods of suppressing harmonic. The one is decreasing harmonic producing based on the harmonic source. The other is increasing filter devices, including passive filter and Active power filter. Then domestic and international of active power filter are introduced. Finally, expatiating the origin, the content and the object.This thesis is shown the content of the passive filter and the active power filter, including the principle, the classification, the advantages and the disadvantages and so on. This thesis is given a new scheme of harmonic detection based on the typical harmonic detecting method. An electric energy special meter chip ATT7022C is used in this thesis, which is a kind of high-accuracy chip used in the electric energy measure. This thesis introduces the principle and characteristic of ATT7022C, and compared to the typical harmonic detecting method. This thesis is mainly contained the system design of active power based on the DSP, which is including hardware design and software design. The main circuit, the auxiliary power source design, the voltage and current sampling circuits are given in the hardware design. The flow charts are given in the software design. In order to verify the accuracy and reliability, the simulation studies are made for the harmonic detecting by MATLAB besides researching in practice. The result is shown that the efficiency of ATT7022C, and shortens the development cycle and advancing the detecting precision. Finally all the work of this dissertation is summarized and the future research work is prospected.