Yaw Control Of Magnetic Levitation Wind Turbine Nacelle Based On Interference Observer

The yaw device of the horizontal-axis wind turbine adopts a multi-motor multi-gear mechanical transmission mechanism,which has the problems of complex structure,large friction loss and high failure rate.The team early proposed a wind magnetic levitation yaw system.Wind has the advantages of high wind precision and low friction loss.In this paper,the two-point suspension synchronization performance of the wind magnetic levitation yaw system needs to be improved,the ultra-low-speed yaw has torque ripple,and the lagging ability of fast-variable interference suppression is built.Moment pulsating yaw electromagnetic torque model,a sliding mode adaptive disturbance observer that takes into account fast-changing interference is proposed,which is combined with the wind turbine nacelle suspension and yaw control,respectively,to achieve a stable suspension and weight of 484 kg wind turbine nacelle The ultra-low speed yaw has improved the dynamic performance of nacelle suspension synchronization and interference suppression,and verified the effectiveness of the proposed control strategy from both simulation and experiment.For the suspension control of the nacelle: First,the two-point suspension height model of the nacelle is converted into the nacelle’s axial synchronous suspension control model.The axial synchronization state feedback control with the integration of axial and synchronization errors is designed respectively.The sliding mode adaptive disturbance observer of the adjustment mechanism adopts the sliding mode term and the slowly varying adaptive interference term to reconstruct the axial and pitch interference,which improves the interference approximation ability and dynamic response;according to the axial synchronization control output and the axial pitch interference Observation values are used to coordinately generate floating current references on both sides of the nacelle,and the inner loop current tracking controller implements the electromagnetic force control of the blade side and tail wing side suspension to complete the stable suspension of the nacelle.A two-point suspension height simulation experimental platform for the wind turbine nacelle was built,and the two-point suspension of the nacelle was simulated and experimentally studied based on the experimental platform of the wind magnetic levitation yaw system built by the research team.The results show that the proposed method achieves the stability of the nacelle Suspension(the steady-state error is only 0.125mm),has strong synchronous tracking performance on both sides,compared with the traditional two-point suspension independent control,its startup time is 5.2s faster,and the steady-state error is reduced by 0.1mm,especially The air gap drop was reduced by 0.19 mm when dealing with unilateral interference.For the yaw control of the nacelle: Aiming at the effects of weak damping,electromagnetic torque ripple and external wind interference on the yaw stability of the nacelle yaw system,based on the axial radial magnetic field decoupling method and double closed-loop cascade of speed and current Control mechanism,a composite speed control strategy based on the combination of speed tracking control,adaptive uncertainty compensation and sliding mode adaptive disturbance observation is proposed.The sliding mode adaptive disturbance observer rebuilds the yaw rapidly changing interference.Feed-compensated speed tracking control improves the ability of yaw motor interference suppression;adaptive uncertainty compensation can effectively deal with the impact of uncertain parts on ultra-low speed yaw control.The simulation and experiment platform of externally excited synchronous motors were built to verify the yaw control strategy proposed in this paper,and the performance analysis under variable operating conditions such as variable speed reference tracking and excitation current adjustment were carried out.Experimental research found that the composite control strategy proposed in this paper achieves 5rpm ultra-low speed yaw operation,and the steady state error is only 0.4rpm.Compared with the traditional speed state feedback control,the dynamic response is increased by 5.2s and the steady state error is reduced by 0.6rpm,when the excitation condition is weakened,the speed fluctuation is reduced by 6.8rpm.