The Study Of Yaw Control System Of Wind Turbine

Wind energy is an inexhaustible, clean resource. Compared with other new energy, wind power technology is more mature to be promoted, so it has been developed all over the world rapidly and becomes the fastest growing energy. For improving the efficiency of wind turbine, increasing the life of the setting and reducing the cost, many researches for wind turbine have been deeply developed in many countries, and many related key technologies have been advanced. But the technology for yaw system has just been developed in a short time, therefore this paper mainly talks about the yaw control system from a deeper aspect. The types of wind turbines are various, so the corresponding yaw systems are also diverse. The object of this paper is about large-power horizontal axis wind turbines which are widely used.For the yaw system, it must keep the cabin always windward, so the wind turbine can catch wind power as much as possible. There are a lot of knottiness for the cabin, like the lag of yaw system and the frequent change of wind direction. The frequent change of wind direction will lead to the frequent movement of yaw system, and this will affect the life of wind turbine consequently. Now the allowable error angle is widely used, which allows the wind direction to change in a certain scope. When the wind direction changes beyond this scope, the yaw system will adjust the direction of cabin.The paper is on the base of the yaw system principle and structure analysis, and according to the features of wind turbine yaw control system, the permanent magnet synchronous motor with vector control is adopted instead of the original AC asynchronous motor to design a closed loop yaw control system,which contains the current, velocity and position loops. The simulation model is established with Matlab. Referring the parameters of 1.5MW wind turbine yaw control system, the system designed here is simulated and the result shows that the system accuracy and response speed are both desirable to achieve the expected yaw operation. In order to meet the robust requirement, the method of acceleration changing gradually is selected to reduce the electromagnetic torque mutation and improve the smooth running of the yaw. For the demand of yaw ratio (the ration of yaw running time to motor running time), the traditional algorithm is improved and the new algorithm can not only guarantee the wind turbine life, but also improve the wind turbine efficiency.