The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 10, 2006
Filed:
Jun. 24, 2004
Toshimitsu Barada, Tokyo, JP;
Toshimitsu Barada, Tokyo, JP;
Ebara Corporation, Tokyo, JP;
Abstract
A magnetic bearing apparatus has an electromagnet having a coil for levitating a rotatable member by a magnetic force and a control device to adjust a gain for levitation control of the rotatable member. The control device includes a displacement sensor to detect a levitated position of the rotatable member, a driver to supply a current to the electromagnet, and a phase compensator to adjust the current based on a signal from the displacement sensor. The control device also includes a band-pass filter into which an output signal of the phase compensator is inputted, an amplifier to amplify an output signal of the band-pass filter at a predetermined amplification ratio, and an adder to add an output signal of the amplifier to an output signal of the phase compensator and supply an added signal to the driver. The band-pass filter has a center frequency based on an actual rotation frequency of the rotatable member, a voltage, a current, or a frequency of a power source for a motor.