Modeling And Control Of Wind Maglev Yaw System

Aiming at the problems of complex structure,high failure rate and high yaw power consumption of yaw device in horizontal axis wind power generation system due to multi-gear transmission.For this reason,the New Energy Resource Institute proposed the wind magnetic levitation yaw system,which greatly reduces the yaw power consumption.Wind magnetic levitation yaw system runs in a harsh environment.The cabin suspension is a multi-degree-of-freedom magnetic levitation system.The cabin yaw under suspension is a disc motor speed control with weak damping and strong interference.How to suppress external interference to achieve stable suspension and yaw under suspension is the key of this paper.Therefore,this paper studies the model construction of the wind magnetic levitation yaw system,multi-degree-of-freedom cabin suspension and yaw speed control at ultra-low speed.Firstly,the multi-degree-of-freedom operation mechanism of the wind-driven magnetic levitation yaw system is analyzed,and the mathematical models of overturning moment,yaw load torque and axial downward pressure of the wind turbine cabin are constructed,and the two-degree-of-freedom motion equations including axial and pitching are established.In view of the coupling of axial and radial magnetic fields in the air gap magnetic field,the suspension electromagnetic forces on both sides of the cabin are given by virtual work method.Considering the differences of suspension air gap,suspension current and external interference,the multi-degree-of-freedom suspension model and yaw motion model of the cabin are constructed.The method of rotor flux orientation is used to decouple the suspension force and yaw torque,and complete independent control of the suspension process and yaw process is realized.Aiming at the two-degree-of-freedom motion mechanism of the wind turbine cabin and the difficulty in measuring the pitch angle,the two-degree-of-freedom motion model is transformed into the two-point suspension motion model of the engine cabin by coordinate transformation method,and the coordinated control strategy of the two-point suspension of the wind turbine cabin is put forward.It includes two-point cooperative suspension tracking control and cross-coupling controller.Two-point cooperative suspension tracking control adopts adaptive suspension tracking control.Based on Lyapunov stability theory,the adaptive law design of suspension model parameters is completed,which greatly improves the suspension air gap tracking and robustness.Then a cross-coupling controller is designed to suppress the synchronization tracking error and improve the synchronization performance of suspension on both sides of the cabin.Aiming at the problem of weak damping,strong disturbance and torque uncertainty caused by overturning moment in yaw control,a yaw speed controller is designedbased on Lyapunov stability theory,and a disturbance torque observer is designed to quickly compensate the influence of uncertain disturbance on speed control.Based on the above control strategies of suspension and yaw,two experiments of power capture and sideslip protection for the yaw system of wind-driven magnetic levitation are carried out respectively.The simulation realizes the ultra-low speed control of suspension stability and yaw speed of the fan cabin,and realizes the maximum power tracking and sideslip protection functions of the fan,which proves the effectiveness of the control strategies of suspension and yaw as well as the effectiveness of the control strategies of wind-driven magnetic levitation and yaw.Rationality of structure design of wind magnetic levitation yaw system.Based on the wind magnetic levitation yaw prototype(suspension weight 484 kg),two suspension converters and yaw converters,the experimental platform of the wind magnetic levitation yaw system was built.Firstly,suspension tracking experiment,axial anti-jamming experiment and lateral disturbance experiment are carried out,and the performance of various suspension control algorithms is compared.Experiments show that the adaptive tracking control method has obvious advantages in rising time,steady-state error and anti-jamming performance.Its suspension steady-state error is only 0.05 mm and synchronization error is only 0.2 mm.Then,the integrated experiment of suspension and yaw was carried out,which realized the rotation of disc motor at(+0.3rpm)ultra-low speed.The suspension air gap was stable during yaw,the fluctuation of suspension air gap was only(+0.3mm),and the fluctuation of yaw speed was only0.0.25r/min.The experiment further verified the effectiveness of the control strategy of suspension and yaw.