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US 11,112,230 B2Granted
Angle sensor using eddy currents
AssigneeAllegro MicroSystems, LLC
InventorsAlexander Latham, Maxim Klebanov
Life of this patent
Estimating the term…
Abstract
Methods and apparatus for a sensor with a main coil to direct a magnetic field at a rotating target for inducing eddy currents in an end of the target and a sensing element to detect a magnetic field reflected from the target, wherein the target end comprises a conductive surface. The reflected magnetic field can be processed to determine an angular position of the target.
Claims84
A sensor, comprising:
- a main coil to direct a magnetic field at a rotatable target for inducing eddy currents in the target;
- differential pick-up coils for detecting a reflected field from the target wherein each of the pick up coils is configured such that an asymmetric reflected field from the target seen by the pick-up coils corresponds to conductive properties of a surface of the target in relation to the main coil and the pick-up coils;
- and
- a processing module to process the reflected magnetic field from the pick-up coils for determining an angular position of the target,
- wherein the target comprises a cylinder and an end of the cylinder is cut at an angle corresponding to the asymmetric reflected field from the target.
2 more elements
A method, comprising:
- employing a main coil to direct a magnetic field at a rotatable target for inducing eddy currents in the target;
- employing differential pick-up coils for detecting a reflected field from the target wherein each of the pick-up coils is configured such that an asymmetric reflected field from the target seen by the pick-up coils corresponds to conductive properties of a surface of the target in relation to the main coil and the pick-up coils;
- and
- processing the reflected magnetic field from the pick-up coils for determining an angular position of the target,
- wherein the target comprises a cylinder and an end of the cylinder is cut at an angle corresponding to the asymmetric reflected field from the target.
2 more elements
A sensor, comprising:
- a main coil means for directing a magnetic field at a rotatable target for inducing eddy currents in the target;
- differential pick-up coil means for detecting a reflected field from the target wherein the differential pick-up coil means comprises pick up coils each configured such that an asymmetric reflected field from the target seen by the pick-up coils corresponds to conductive properties of a surface of the target in relation to the main coil means and the pick-up coils;
- and
- a processing means for processing the reflected magnetic field from the pick-up coils for determining an angular position of the target,
- wherein the target comprises a cylinder and an end of the cylinder is cut at an angle corresponding to the asymmetric reflected field from the target.
2 more elements
A sensor, comprising:
- a main coil to direct a magnetic field at a rotatable target for inducing eddy currents in the target;
- differential pick-up coils for detecting a reflected field from the target wherein each of the pick up coils is configured such that an asymmetric reflected field from the target seen by the pick-up coils corresponds to conductive properties of a surface of the target in relation to the main coil and the pick-up coils;
- and
- a processing module to process the reflected magnetic field from the pick-up coils for determining an angular position of the target,
- wherein a first one of the pick up coils generates a sine signal corresponding to the angular position of the target and a second one of the pick-up coils includes a cosine signal corresponding to the angular position of the target.
2 more elements
A sensor, comprising:
- a main coil to direct a magnetic field at a rotatable target for inducing eddy currents in the target;
- differential pick-up coils for detecting a reflected field from the target wherein each of the pick up coils is configured such that an asymmetric reflected field from the target seen by the pick-up coils corresponds to conductive properties of a surface of the target in relation to the main coil and the pick-up coils;
- and
- a processing module to process the reflected magnetic field from the pick-up coils for determining an angular position of the target,
- wherein the pick-up coils comprise first and second matching coils that are ninety degrees out of phase with respect to each other.
2 more elements
A method, comprising:
- employing a main coil to direct a magnetic field at a rotatable target for inducing eddy currents in the target;
- employing differential pick-up coils for detecting a reflected field from the target wherein each of the pick-up coils is configured such that an asymmetric reflected field from the target seen by the pick-up coils corresponds to conductive properties of a surface of the target in relation to the main coil and the pick-up coils;
- and
- processing the reflected magnetic field from the pick-up coils for determining an angular position of the target,
- wherein a first one of the pick-up coils generates a sine signal corresponding to the angular position of the target and a second one of the pick-up coils includes a cosine signal corresponding to the angular position of the target.
2 more elements
A method, comprising:
- employing a main coil to direct a magnetic field at a rotatable target for inducing eddy currents in the target;
- employing differential pick-up coils for detecting a reflected field from the target wherein each of the pick-up coils is configured such that an asymmetric reflected field from the target seen by the pick-up coils corresponds to conductive properties of a surface of the target in relation to the main coil and the pick-up coils;
- and
- processing the reflected magnetic field from the pick-up coils for determining an angular position of the target,
- wherein the pick-up coils comprise first and second matching coils that are ninety degrees out of phase with respect to each other.
2 more elements
Dependencies are inferred from the claim text.