MAGNETIC BEARING DEVICE AND BIAS CURRENT SUPPRESSION METHOD OF MAGNETIC BEARING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a magnetic bearing device which can suppress the generation of touch-down while reducing power consumption.SOLUTION: First and second radial magnetic bearings 6, 7 of a magnetic bearing device have a pair of electromagnets (first electromagnets) 29Xa, 29Xb (29Ya, 29Yb), 30Xa, 30Xb (30Ya, 30Yb) which are arranged so as to sandwich a rotating body 4 from both sides in one direction orthogonal to a rotating shaft of the rotating body 4. A control unit 4 supplies first excitation currents which are obtained by superimposing control currents (first control currents) which are properly changed according to a magnitude of displacement (first displacement) in a direction orthogonal to the rotating shaft of the rotating body 4 on bias currents (first bias currents) to electromagnets 28a, 28b. Then, the control unit further performs variable bias current control which increases magnitudes of the bias currents accompanied by an increase in the magnitude of the displacement (first displacement), and decreases the magnitudes of the bias currents accompanied by a decrease in the magnitude of the displacement (first displacement).