Design And Research Of Active Power Filter In The Power Transmission System

With the development of modern industry, a lot of power electronic equipment scale have using, power transmission system produced a large number of odd harmonics, which have caused serious pollution of power quality, and recurred great harm with People’s Daily life and production. Take the necessary measures to suppress the harmonics and improve power quality are imperative. Today, the technology to restrain the harmonics is mainly composed of two kinds:one is optimized electrical equipment from harmonic source, The second is parallel or serial filter unit, active power filter (APF) is recognized as one of the best means of control of harmonic pollution in technology, to make applied research has the very big practical significance. This article discusses the instruction current theoretical analysis and detailed design of the circuit operation, how to real-time detect power supply system with the three-phase three-wire and three phase four wire made in-depth analysis of harmonic component.This paper introduces the concept of harmonic, harmonic harm to power system are analyzed, and expounds the method of harmonic governance. Then the theory of p-q and Clarke transform based on instantaneous reactive power theory has applied in three phase three wire and the improved algorithm use in three phase four wire system. Then this paper has introduced the main structure of the shunt active power filter and used for current waveform sine principle, Positive sequence voltage detector and phase lock loop are introduced, and it use in three phase four wire system. Finally, software and hardware have designed, including harmonic current operation system based on TMS320F2812chip and other peripheral circuit module, such as power circuit, IGBT (Insulated Gate Bipolar Transistor) drive circuit, man-machine interface module and a dc voltage measurement circuit. Then design principle, software development environment and write the software flow chart have introduced.Design of shunt active power filter system has simulated across MATLAB7.0/Simulink6.0, the results affirmed the feasibility of the software and hardware design in this paper. The experimental result has value for design and simulation of APF.