Two Degrees-of-Freedom Cooperative Suspension Control for Maglev Wind Yaw System

The article proposes maglev wind yaw system for wind turbine to yaw for wind. Two degrees-of-freedom (2-DOF) suspension model is constructed with the suspension current dynamics. A dual-loop cooperative suspension control including inverse system compensation, pseudo suspension control, and hybrid decoupling control is proposed to ensure nacelle stable suspension without pitching. The inverse system compensation gives the nominal current reference; and then the pseudo suspension control is designed from sliding mode controller with the nonlinear function to acquire two pseudo control input, and then 2-DOF disturbance observers based on two sliding mode surfaces and their sign function are proposed to get high-frequency interference, and cooperate with the linear relationship to decouple and give two sides current reference. The closed-loop stability of nacelle suspension has proved by the Lyapunov function, air gap asymptotic tracking can be reached in finite time. The state feedback controller with adaptive compensation is designed to enhance the current dynamic response. Finally, the simulation and experimental results show that the proposed strategy has faster suspension dynamic response, smaller steady-state error, and synchronization error.