Nonlinear Vibration Analysis and Experiments of a Vertical Rigid Rotor-Magnetic Bearing System (Case Considering the Delay of Control Force)

Active magnetic bearings (AMB) become to be widely used in various kinds of rotating machinery. However, as the magnetic force is essentially nonlinear, nonlinear phenomena may occur when the rotating speed becomes higher. In this paper, the magnetic force is modelled considering the 1st order delay in the control current from the control signal, and the AMB force is represented by a power series of the control current and displacement. The nonlinear theoretical analysis of vertical rigid rotor-AMB system is achieved. Then, the effect of the delay of control current and AMB parameters on the nonlinear phenomena is clarified theoretically and experimentally.