The Integration Study Of Fan Electric Pitch Drive

In recent years, electric pitch system replaces hydraulic pitch system,and becomes the mainstream of wind turbines, because it has someadvantages, such as strong adaptability, fast response speed, no oilpollution, easy to control. The key models of electric pitch system are pitchservo motor, pitch servo drives, backup power, pitch master and othermodules. In traditional structure, backup power and servo driver are twodiscrete elements, so the structure is relatively complex, and the twoelements connection points are important fault point in strong shocks ofthe hub. Aiming at these shortcomings, the paper designs a new integratedstructure, putting the backup power and servo drive in an integrated model.This structure improves the safety performance and serviceability ofsystem.The second chapter expounds the basic theory of electric pitch system.According to the demands of wind turbine, it designs drive circuit of servodrive and charge-discharge circuit of backup power, confirms that pitchmotor is PMSM, backup power is super-capacitor, and type of them. Onthis basis, it designs the integral structure of integrated drive.The third chapter studies vector control strategy of PMSM andconstant-current limit voltage charge of super-capacitor, establishes themathematical model of PMSM, super-capacitor model, and the model ofsystem in MATLAB. According to the different work modes of windturbine, system has carried on the simulation, and the results prove thefeasibility of integrated drive in the theory.According to demand of the integration system, the fourth chapteranalyzes the integrated system’s control demand of servo drive andsuper-capacitor charge, identifies the controller, the auxiliary power modeland sampling circuit design. And it sets up the integrated hardware structure of system, establishes the software control flow of system.Finally, it set up the experimental platform. The experimental resultsshow that the integrated drive has a good dynamic response performanceand robustness, proves its feasibility in the practical engineering.