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US 6,472,787 B1Granted
Controller of magnetic bearing
AssigneeKoyo Seiko Co., Ltd.
InventorsHironori Kameno, Hirochika Ueyama
Life of this patent
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Abstract
In a control unit for magnetic bearing, a sampling frequency of a DSP 4 is varied according to a number of rotation of a rolling element 1. Thus, a frequency band to be damped by a notch filter 42 as a digital filter is varied in correspondence with a resonance frequency associated with a natural frequency and a rotational vibration frequency, thereby to damp a resonance signal contained in a control signal. The occurrence of resonance is thus prevented through digital control.
Claims2
A control unit for magnetic bearing comprising:
- number-of-rotation sensing means for sensing a number of rotation of a rolling element supported by a magnetic bearing;
- sampling frequency decision means for varying a sampling frequency according to variation of the number of rotation sensed by said number-of-rotation sensing means;
- displacement sensing means for sensing a displacement of said rolling element and outputting a digital displacement signal based on a sensed displacement;
- control means for outputting a control signal for the positional control of said rolling element based on the digital displacement signal outputted from said displacement sensing means, said control means performing a predetermined digital filtering processing at the sampling frequency provided by said sampling frequency decision means thereby varying a cutoff frequency according to the sampling frequency, to output the control signal with a damped frequency band including a resonance frequency associated with a natural frequency varying with the number of rotation of said rolling element and a rotational vibration frequency;
- and
- electromagnet control means for controlling an electromagnet of the magnetic bearing based on the control signal outputted from said control means.
3 more elements
Dependencies are inferred from the claim text.