Patent US4439822A successfully refreshed from Google Patents.
US4439822A
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Method and apparatus for detecting and preventing impending magnetic saturation in magnetic materials
Assignee: California Institute of Technology
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Filing: 1982-03-26
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Granted: 1984-03-27
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Expires: 2002-03-26
Abstract
Abstract A method and apparatus is disclosed for detecting an impending saturation in nonlinear magnetic material for particular operating conditions, such as in a core of a power transformer T 1 of a switched-mode converter, in response to a varying magnetic field in a principal direction induced by a drive current through its primary winding with its axis aligned in the principal direction. A transverse flux sense winding (20) is used in monitoring the rate of change of flux density of a transverse magnetic field to produce a voltage proportional thereto. That voltage is compared in a comparator (22) with a predetermined threshold voltage characteristic of impending saturation of the core. The output of the comparator is used for controlling drivers (25) to prevent saturation of the switched-mode converter bias switching the drivers off alternately when the sensed voltage reaches the predetermined threshold set at the comparator (22).
Inventors
- 👤 Alan G. Cocconi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:15
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/40; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/337; H02M3/3376; H02M3/3378
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
98 words
A method of detecting an impending saturation in nonlinear magnetic material for particular operating conditions in response to a varying magnetic field in a principal direction induced by a drive current through a coil around said material, said coil having its axis aligned in said principal direction, comprising the step of monitoring the rate of change of flux density of a magnetic field orthogonal to said varying magnetic field to produce a voltage proportional thereto, and the step of comparing said voltage with a predetermined threshold voltage characteristic of impending saturation of said material in said operating conditions.
Claim 2
Independent Claim
98 words
A method of detecting an impending saturation in nonlinear magnetic material for particular operating conditions in response to a varying magnetic field in a principal direction induced by a drive current through a coil around said material, said coil having its axis aligned in said principal direction, comprising the step of monitoring the rate of change of flux density of a magnetic field orthogonal to said varying magnetic field to produce a voltage proportional thereto, and the step of comparing said voltage with a predetermined threshold voltage characteristic of impending saturation of said material in said operating conditions.
Claim 3
Dependent Claim
33 words
A method as defined in claim 1 including the step of controlling said drive current to prevent saturation in response to the result of comparing said voltage with a predetermined threshold voltage characteristic.
Claim 4
Dependent Claim
43 words
A method as defined in claim 2 practiced for prevention of saturation of a power transformer in a switched-mode converter wherein the step of controlling said drive current is comprised of switching said drive current off when said voltage reaches said predetermined threshold.
Claim 5
Dependent Claim
90 words
Apparatus for detecting an impending saturation in nonlinear magnetic material for particular operating conditions in response to a varying magnetic field in a principal direction induced by a drive current through a coil around said material, said coil having its axis aligned in said principal direction comprising means for monitoring the rate of change of flux density of a transverse magnetic field to produce a voltage proportional thereto, and means for comparing said voltage with a predetermined threshold voltage characteristic of impending saturation of said material in said operating conditions.
Claim 6
Dependent Claim
90 words
Apparatus for detecting an impending saturation in nonlinear magnetic material for particular operating conditions in response to a varying magnetic field in a principal direction induced by a drive current through a coil around said material, said coil having its axis aligned in said principal direction comprising means for monitoring the rate of change of flux density of a transverse magnetic field to produce a voltage proportional thereto, and means for comparing said voltage with a predetermined threshold voltage characteristic of impending saturation of said material in said operating conditions.
Claim 7
Dependent Claim
32 words
Apparatus as defined in claim 4 further comprising means for controlling said drive current to prevent saturation in response to the result of comparing said voltage with a predetermined threshold voltage characteristic.
Claim 8
Dependent Claim
53 words
Apparatus as defined in claim 5 wherein said magnetic material is the core of a power transformer in a switched-mode converter, and wherein said means for controlling said drive current is comprised of means for switching said drive current off in response to said comparing means when said voltage reaches said predetermined threshold.
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) | 1987-03-27 | 1987-09-26 | 1988-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-27 | 1991-09-26 | 1992-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-27 | 1995-09-26 | 1996-03-27 | $7700.00 | Window Closed / Lapsed |