Research On Main Circuit And Control Strategy Of New Multi-switches Active Power Filter

The widely use of power electronic equipment leads to large power quality pollution, all kinds of accidents that caused by harmonics often make huge economic losses to the society. Active power filter(Active Power Filter, APF) is an effective means to eliminate the grid harmonics and compensate the reactive power. It has been applied in and out seas. But with the development of the power grid, to the requirements of APF also increases. In order to improve the capacity of the APF system and maintain good performance, it becomes a new research direction of APF in recent years. This paper mainly studies the multilevel active power filter structure of the main circuit, harmonic detection method and corresponding control strategy. Firstly, it introduces the current status of research on active power filter analysis in and out seas, and analyzes the development trend of the future.After that, it analyzes the filtering principle of APF, and introduces the classification and structure of APF. This paper gives the main circuit structure of multilevel active filter in details. Based on the classic structure of the main circuit, the paper presents a new novel multi-level main circuit structure, the structure has decreased in the switch the number, its working principle is analyzed, and the mathematical model analysis, the model structure of the main circuit designed by using linear analysis conclusion.Secondly, it introduces several harmonic detection theory and compares their advantages and disadvantages, the details of the principle of harmonic detection based on instantaneous reactive power theory, and makes a detailed description of the detection methods of the commonly used p-q and ip-iq two harmonic current, improved based on ip-iq detection method, and omit the coordinate transformation, increase the preset with the dead time compensation angle switching device in voltage converter, and the three methods are compared and verified by MATLAB simulation software.Finally, it gives the design of the simulation parameters, the simulation model, using MATLAB simulation software simulation. The simulation results show that, the proposed multi-level main circuit structure, improved detection methods and specific harmonic elimination control method is correct and effective.