Modeling of Non-laminated Electromagnetic Suspension Systems

Eddy currents induced within non-laminated electromagnetic actuators by time-varying magnetic fields have a strong effect on the dynamics and control of electromagnetic suspension systems. This paper examines the modeling of these suspension systems and resolves two important problems: 1) the effect of time varying floater position on electromagnetic force production and 2) the proper manner in which to model voltage-mode operation of the suspension. The models developed are explicit functions of actuator material and geometric properties. The investigation focuses on axisymmetric cylindrical electromagnetic actuators. Similar results are provided for non-laminated actuators with C-core stators. Experimental results are presented that demonstrate the accuracy of the modeling approach.