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:
Feb. 13, 1996
Filed:
May. 17, 1994
Naohiko Takahashi, Ibaraki, JP;
Minoru Hiroshima, Ushiku, JP;
Osami Matsushita, Ibaraki, JP;
Yasuo Fukushima, Tsuchiura, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A magnetic bearing is provided with a simulating circuit for estimating a displacement of a rotor on the basis of a force which is exerted on the rotor. An output of the simulating circuit is compared with an actual displacement signal. A delay circuit and a subtracter are provided to subtract a run-out, which was estimated one period before the rotation of the rotor, from the displacement signal. A displacement signal from which the run-out component was eliminated is set to a new displacement signal. A signal which is obtained by adding an estimated run-out of one period before, namely, an output of the delay circuit to the run-out which was estimated by comparing the output of the simulating circuit with the new displacement signal is newly inputted to the delay circuit. Due to this, the run-out component is eliminated from the displacement signal of the magnetic bearing, the load on power amplifiers for driving the electromagnets is reduced, there is a surplus for a saturation which is caused in a high frequency band, the reliability of the control system is improved, and deterioration of positional accuracy due to the run-out is prevented.