Abstract: To solve coexistent problem of zero-power and resisting eccentric load in the clean transmission system using hybrid magnetic levitation, a novel system structure with the movable magnet unit is proposed and concomitant control strategies are designed. One magnetic pole is fixed, while the other two can rotate around the central axis of the levitated plate. Under levitation with the eccentric load, the zero-power and horizontal levitation could be realized by adjusting air gap to overcome the disturbance force and changing the position of magnet to counteract the moment introduced by eccentric load. Firstly, the linear parameter-varying model is established, and the conditions for the system to achieve zero power horizontal suspension are analyzed. The zero-power control strategies with resisting eccentric load introduces the integral feedback of current and air gap deviation in the proportional-differential controller, and uses the centroid observer to reverse the rotation angle of the magnet. The solving methods are implemented by inverse Jacobian transform matrix and look-up table with interpolation respectively. The experimental results show that the system can maintain zero power horizontal suspension under eccentric load. In terms of rectifying deviation and fluctuation of steady-state current, the continuous control strategy using Jacobi is superior to the discrete look-up table strategy.

Key words: hybrid magnetic levitation, zero-power control, characteristic of resisting eccentric load, discrete control