The Research Of Active Power Filter Control Technology

As the traditional means of harmonic compensation, Passive Filter(PF) can only filtrate specific harmonic, have a disadvantage of producing series-parallel connection resonance with grid and will be replaced by new equipment step by step. Active Power Filter(APF) is widely considered the most effective method to solve harmonic and reactive power pollution, improve the power quality, and become a new researchful hotspot of electric and electronic technology application.First, the article classifies the APF from three aspects: the main circuit framework, method to connecting grid and form of power supply, and detailedly introduces their configuration and applicable occasion. The APF which is shunt, 3-leg 3-wire and voltage source inverter(VSI), as the most typical one, is regarded as research object, and introduced its frame and theory. Then how to select power switch in main circuit and design buffer-circuit and drive-circuit is discussed. Using the means of theory analysis and emulational experiment, the method of deciding AC-inductance and DC-capacitance is given. After introducing some common current detection methods, the article, aiming at 3-leg 3-wire circuit, studies p-q and ip-iq technique based on the Instantaneous Reactive Power theory, and designs the hardware circuit. On control aspect, after introducing several current tracking control methods and discussing their advantages and disadvantages, a Hysteresis-Triangular-carrier current control mean is brought out, and to be validated by emulation. Finally, the article introduces the essential theory and method of DC bus capacitance control. On the base of traditional PI method, a Fuzzy-PI mix control is put forward. Two methods comparison is given through emulation.