Active And Passive Levitation Control Of Wind Magnetic Levitation Yaw System

In view of the large frictional power consumption and high failure rate of the yaw device of the horizontal axis wind power generation system,the research group proposed a wind magnetic levitation yaw system,the wind turbine cabin floats and yaws against the wind,greatly reducing the yaw power consumption.However,the wind yaw system works on a tower of 80 m high,and the working condition is bad,especially the overturning moment caused by the windward area with large difference between the engine blade and the tail side,which makes the nacelle extremely easy to pitch,and the fan has multiple degrees of freedom such as axial,pitch and yaw.The traditional multi-converter cooperative suspension strategy has many problems such as a large number of sensors and converters,large suspension power consumption,and high failure rate,for this reason,the paper proposes the active and passive suspension cooperative control of the wind turbine cabin,passively raises the pitch stiffness damping,and actively suspends the fan cabin to cooperate to complete the stable suspension of the wind cabin.Firstly,the suspension mechanism and force analysis of wind suspension yaw system are studied in depth,the model of winding overturning moment and axial downforce are given,the eddy damping force and levitation force on both sides of the nacelle are theoretically derived.The two-degree-of-freedom equation of motion of the nacelle is constructed,the eddy current damping is introduced to improve the suspension performance of the disc permanent magnet and the stability of the controller,the effects of thickness,suspension air gap and current on the eddy current damping force are studied by simulation.Finally,considering the suspension power consumption,air gap fluctuation and converter load,the thickness of the eddy aluminum plate is optimized,and the simulation is based on the optimization of the thickness of the aluminum plate,the system air gap fluctuation is only 1mm and the current reduction can reach 3A.This paper proposes the active and passive suspension coordinated control of the wind turbine cabin,including the eddy current damping system with integrated suspension winding and aluminum plate and the composite method of moving the center of gravity of the cabin,as well as the axial suspension control of the nacelle.Based on the rated overturning moment of the fan and the maximum allowable pitch angle,the design of the lower center of gravity of the nacelle and the improvement of the pitching damping are completed.In view of the current lag problem caused by the large inductance of the suspension winding in the cabin,a cascaded control of the floating air gap outer ring and the current inner loop phase is adopted,and a current tracking controller based on back electromotive force compensation is proposed toimprove the current tracking speed;For the problem of non-linear suspension,weak damping and pitch-free interference in the cabin,the adaptive interference compensation and RBF neural network algorithms are used to quickly approximate many uncertainties in the fan suspension system,and the suspension stability controller is used to realize the stable suspension of the nacelle.The simulation experiment shows that the two algorithms can apply the maximum fluctuation of the air gap to 0.3mm and 0.25 mm when the overturning moment is 150 Nm,which is much better than the 1.2mm of the air gap fluctuation of the PID control.The air gap difference on both sides of the nacelle is greatly reduced.The pitch angle satisfies the design requirements and verifies the effectiveness of the active and passive suspension control strategies.Based on the 3kW suspension converter and the wind magnetic levitation yaw prototype weighing 484 kg,the test platform of the wind magnetic levitation yaw system was built,and the suspension performance comparison test of the multi-aluminum plate thickness and the main passive suspension test of the cabin under the application of 150 Nm overturning moment were carried out.The test found that: 1)Based on the optimized aluminum plate thickness suspension system,the pressure in the 225 N engine room Under the action,the floating air gap fluctuates by0.125 mm,which is much better than the unoptimized air gap fluctuation of 4mm,which verifies the effectiveness of eddy current damping optimization.2)The adaptive disturbance compensation algorithm has a cabin suspension steady-state error of 0.2 under the action of150 Nm overturning moment.Mm,the maximum floating air gap difference on both sides of the nacelle is 0.2mm,and it only gradually converges in 1.3s,which further validates the effectiveness of the active and passive suspension control strategy proposed in this paper.