Dynamics of Active Magnetic Thrust Bearings

抄録

A linear model considering the effect of eddy currents is shown to be useful for the analysis of the dynamics of active magnetic thrust bearings in which electromagnet cores are composed of solid steel. The dynamics of the magnetic control force are modeled by the first-order time-lag system with unknown parameters : gain and time constant. The parameters are estimated from experimental results that indicate the static relation between the coil current and the magnetic control force, and the frequency response of magnetic flux for an input signal to a power amplifier. The effect of eddy currents on the dynamics is confirmed by the frequency characteristlcs of magnetic flux for the coil current. Model simulations with estimated parameters are compared with experimental results, and good agreement is obtained in frequency response in a linear range and in impulse responses with rotor displacements smaller than half the air gap.