Development Of Variable Frequency Yaw Controller For Wind Turbine

The yaw control system of the wind turbine drives the nacelle to rotate through the motor to keep the blades aligned with the wind direction to capture the maximum wind energy.In the early days,the yaw control system mostly used direct motor drive to drive the nacelle.When the angle between the nacelle and the wind direction differs by more than 15 degrees,the drive motor is directly used to adjust the yaw angle.This direct projection method will inevitably bring current and mechanical shocks.Current impact will cause the switch to trip and the yaw cannot be restored and can only be restored manually;mechanical impact causes gear wear,which shortens the mechanical life of the yaw system and increases maintenance costs.The use of variable frequency drive yaw motors can eliminate the problems caused by direct input motors.This paper develops a variable frequency yaw controller for yaw motors,and mainly carried out the following work:The overall scheme design of variable frequency yaw controller.Analyze the structure of the yaw drive system of the wind turbine,and point out two problems with the yaw system:one is that the current impact of the yaw motor is large when the yaw system is started,and the other is that multiple yaw motors carry loads when the yaw system is running.The problem of imbalance.In view of the large current impact of the yaw motor,the starting characteristics of the yaw motor are studied and analyzed,and a variable frequency soft start scheme is designed;for the problem of unbalanced load of multiple motors,the cause of this problem is researched and analyzed,and a one-to-one multi-motor is proposed.Parallel variable frequency yaw control scheme.Load balance control analysis of yaw motor.In view of the frequent load changes of the wind power yaw system and the unbalanced load of the multi-motor system,two schemes of speed-current double closed-loop control and characteristic control are proposed.Based on the basic principles of vector control,the variable frequency speed regulation control of asynchronous motors is studied;the multi-motor control system is established,and the model is simplified according to the characteristics of vector control,and the basic principles of multi-motor load balancing control are studied.Experimental platform construction and experimental verification.A simulation model is built based on MATLAB/Simulink platform,and the feasibility and correctness of the multimotor load balancing control strategy proposed in this paper are verified by simulation.Design a prototype of a multi-motor variable frequency yaw controller,complete hardware circuit debugging and control software design.An experimental platform is built,and asynchronous motor soft-start experiments and multi-motor load balancing experiments are carried out.The experimental results show that the solution proposed in this paper can solve the problem of large starting current impact of yaw motors and load imbalance when multiple yaw motors are running.This thesis studies and analyzes the structure of the wind turbine yaw drive system,designs a multi-motor variable frequency yaw controller prototype,and through experiments,preliminary verification of the multi-motor load balancing control algorithm,and finally the developed variable frequency yaw controller on the network run.