US4623202A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-linear control type magnetic bearing
Assignee: Toshiba Corp
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Filing: 1985-05-22
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Granted: 1986-11-18
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Expires: 2005-05-22
Abstract
Abstract A non-linear control type magnetic bearing comprises a pair of electromagnets for magnetically attracting an object so as to permit it to be levitated therebetween, a current supply circuit for alternately supplying an excitation current to the pair of electromagnets, a circuit for generating a pair of current level signals corresponding to the levels of the currents through the respective electromagnets, a velocity sensor for generating a velocity signal corresponding to a velocity with which the object is moved, a difference circuit for generating a difference signal corresponding to a pair of current level signals, a differentiating circuit for differentiating the velocity signal to generate an acceleration signal corresponding to the acceleration rate of the object, an analog operating circuit for generating a position displacement signal corresponding to the position of displacement of the object by substituting a difference signal and acceleration signal into an equation of motion of the object, and a switching discriminator circuit for identifying a positive or a negative sign of a linear equation of the position displacement signal and velocity signal and for supplying to a current supply circuit a switching signal which alternately switches a supply of current to the respective electromagnets.
Inventors
- 👤 Shitta Shingu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:52
CPC Classifications
F; F16; F16C; F16C32/00; F16C32/04; F16C32/0406; F16C32/044; F16C32/0444; F16C32/0451; F16C32/0446; F16C32/0474; F16C32/0476
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
226 words
A non-linear control type magnetic bearing comprising: a pair of electromagnet means, disposed opposite to each other in a spaced-apart relation with an object to be levitated therebetween, for attracting the object under their magnetic force; current supply means for alternately supplying excitation current to the respective electromagnets; means for detecting the levels of the currents flowing through the respective electromagnets and for generating a pair of current level signals; velocity sensor means for detecting the velocity with which the object is moved in the mutually opposite directions of the electromagnets and for generating a velocity signal; difference means for finding a difference between the pair of current level signals and for generating a difference signal; differentiating means for differentiating the velocity signal and for determining an acceleration rate of the object to generate an acceleration signal; analog operation means for performing an analog operation on an equation of motion of the object through the use of the difference signal and acceleration velocity signal to find a position displacement of the object and for generating a position displacement signal; and switching discriminator means for judging a positive or a negative sign of a linear equation for the position displacement signal and velocity signal and for supplying to the current supply means a switching signal which alternately switches a supply of a current to the respective electromagnets.
Claim 2
Dependent Claim
226 words
A non-linear control type magnetic bearing comprising: a pair of electromagnet means, disposed opposite to each other in a spaced-apart relation with an object to be levitated therebetween, for attracting the object under their magnetic force; current supply means for alternately supplying excitation current to the respective electromagnets; means for detecting the levels of the currents flowing through the respective electromagnets and for generating a pair of current level signals; velocity sensor means for detecting the velocity with which the object is moved in the mutually opposite directions of the electromagnets and for generating a velocity signal; difference means for finding a difference between the pair of current level signals and for generating a difference signal; differentiating means for differentiating the velocity signal and for determining an acceleration rate of the object to generate an acceleration signal; analog operation means for performing an analog operation on an equation of motion of the object through the use of the difference signal and acceleration velocity signal to find a position displacement of the object and for generating a position displacement signal; and switching discriminator means for judging a positive or a negative sign of a linear equation for the position displacement signal and velocity signal and for supplying to the current supply means a switching signal which alternately switches a supply of a current to the respective electromagnets.
Claim 3
Dependent Claim
42 words
A magnetic bearing according to claim 1, in which said current supply means comprises: a power supply for supplying excitation currents to the pair of electromagnets; and switching means for alternately switching a supply of the excitation currents to the respective electromagnets.
Claim 4
Dependent Claim
17 words
A magnetic bearing according to claim 2, in which said switching means is comprised of a transistor.
Claim 5
Dependent Claim
16 words
A magnetic bearing according to claim 2, in which said switching means is a power relay.
Claim 6
Dependent Claim
76 words
A non-linear control type magnetic bearing according to claim 1, further comprising judging means for judging whether or not a predetermined current flows for over a predetermined period of time through one of the pair of electromagnets and for supplying, when a predetermined current continuously flows for over a predetermined period of time, to the switching discriminator means a judgment signal for forcing a current through said one electromagnet to be switched to the other electromagnet.
Claim 7
Dependent Claim
41 words
A magnetic bearing according to claim 5, in which said current supply means comprises: a power supply for supplying the respective currents to the respective electromagnets; and switching means for alternately switching a supply of excitation current to the respective electromagnets.
Claim 8
Dependent Claim
23 words
A magnetic bearing according to claim 6, in which said judging means is connected between said power supply means and said switching means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-11-17 | 1990-05-19 | 1990-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-17 | 1994-05-19 | 1994-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-17 | 1998-05-19 | 1998-11-18 | $7700.00 | Window Closed / Lapsed |