Study Of Detection And Suppression Of Harmonics By The Excitation System Of The Doubly-fed Machine

Main energy form of the human production and life is still electricity. The technology of ac excitation changed the large generator traditional mode of constant speed constant frequency electric, the operating condition and performance of generator have improved and can be used in the tidal power, wind power and hydropower station, can be applied in the direction of the field and more.This paper first introduced the development trend of the doubly-fed generators and excitation system, but the analysis of doubly-fed machine speed regulation system found that when doubly-fed machine first started, the start on the soft measures can reduce the instantaneous torque starting motor and the peak current of rotor winding, stator winding, and improve the performance in the motor, second to excitation system of doubly-fed generators which is harmonic characteristic over inverter rotor side are analyzed, and converter the simulation analysis. In the final,based on instantaneous reactive power, this paper analysis the detection methods theory of power harmonic and thses two inspection operation ways were analyzed and compared, determine operation mode which is suitable for doubly-fed generators excitation system of harmonic detection. Based on the influence of the electric power system harmonic, eliminating it is required, so as to improve the quality of electric power output.the last chapter describes the harmonic method, which is used mixed type filter (HAPF) to undertake inhibition of harmonic and design the topological structure of hybrid filter.