| 摘要 |
PROBLEM TO BE SOLVED: To provide a sensor-less magnetic bearing control device having a simple system structure without requiring a special digital arithmetic processing. SOLUTION: A bias voltage source 12 for supplying a bias current required to maintain the linear characteristic of electromagnets, and a control current source 7 for supplying the exciting current required to control a rotor to be floated for support at a desirable position, while overlapping with the bias current from the bias voltage source, are connected to the electromagnets 10 and 11 forming a magnetic bearing. The exciting current output from the control current source is supplied to the pair of electromagnets, which are arranged opposite to each other, at an opposite duty ratio by controlling the magnetic bearing control voltage source to modulate an amplitude of the pulse. The duty ratio is controlled so that impedance of each of the pair of electromagnets, which changes in response to position of the rotor 13, becomes equal to each other. COPYRIGHT: (C)2004,JPO
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