Four-Point Adaptive Suspension Control for Maglev Wind Yaw System

A magnetic-levitation (maglev) Wind Yaw System is proposed to make the nacelle yaw for wind direction without friction. Due to the multi-point suspension nonlinear coupling and higher suspension weight, a double closed-loop control strategy for single-point suspension control is proposed including suspension air gap loop and the current tracking loop. A MDOF dynamic model based on the mechanical geometry and motion dynamics is developed and then transformed into the mult-point suspension model. Then we unify the cross coupling terms and pitching disturbance into synchronous disturbance, and then proposed a composite control strategy to set suspension current reference for current tracking loop, including main tracking controller, adaptive synchronization controller and adaptive disturbance controller. The multi-point suspension simulation platform of maglev wind yawing system is built to carry out the dynamic suspension tracking and pitching disturbance experiment, and the poposed strategy has good dynamic tracking ability, the steady-state air gap error is only 0.003mm, and the reference switching recovery time is 0.445s . As pitching torque of 220Nm is subjected to the nacelle, the maximum air gap fluctuation is only 0.38mm, and the maximum synchronization error is 0.19mm, but these of the PID controller can reach to 2.82mm and 10mm respectively, which validate the proposed composite control and the rationality of four point nacelle suspension.