Systems, methods, and apparatus for detecting ferromagnetic foreign objects in a predetermined space

• US 10,324,215 B2
• Filed: 05/22/2015
• Issued: 06/18/2019
• Est. Priority Date: 12/30/2014
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: Widmer, Hans Peter, Sieber, Lukas, Daetwyler, Andreas
• Primary Examiner(s): Koval, Melissa J
• Assistant Examiner(s): McDonnough, Courtney G
• Application Number:
  US14/720,539
• Publication Number:
  US 20160187519A1
• Time in Patent Office: 1,488 Days
• Field of Search: None
• CPC Class Codes: B60L 2200/12 Bikes
• CPC Class Codes: B60L 2200/22 Microcars, e.g. golf cars
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60L 53/30 Constructional details of charging stations
• CPC Class Codes: B60L 53/305 Communication interfaces
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• CPC Class Codes: B60L 53/65 involving identification of vehicles or their battery types
• CPC Class Codes: B60L 53/665 Methods related to measuring, billing or payment
• CPC Class Codes: B60L 53/68 : Off-site monitoring or control, e.g. remote control
• CPC Class Codes: B60L 55/00 : Arrangements for supplying energy stored within a vehicle to a power network, i.e. vehicle-to-grid [V2G] arrangements
• CPC Class Codes: G01V 3/10 : using induction coils
• CPC Class Codes: H02J 50/10 : using inductive coupling
• CPC Class Codes: H02J 50/12 : of the resonant type
• CPC Class Codes: H02J 50/90 : involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00034 : Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: Y02E 60/00 : Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 : Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 10/126 : the energy generation units being or involving electric vehicles [EV] or hybrid vehicles [HEV], i.e. power aggregation of EV or HEV, vehicle to grid arrangements [V2G]
• CPC Class Codes: Y04S 30/12 : Remote or cooperative charging
• CPC Class Codes: Y04S 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

An apparatus for detecting a presence of an object includes an inductive sensing coil that is configurable to generate a first magnetic field. The inductive sensing coil is configured to have an electrical characteristic that is detectable when generating the first magnetic field. The electrical characteristic is configured to vary as a function of a second time-varying magnetic field simultaneously applied to the object. The apparatus comprises a controller configured to detect a change in the electrical characteristic and determine a presence of the object based on the detected change in the electrical characteristic. The electrical characteristic comprises one or more of an equivalent resistance, an equivalent inductance, an equivalent impedance, and an impulse response of the inductive sensing coil. The object comprises one or more of a ferromagnetic object, a metallic film and a metallic foil.

Claims

1. An apparatus for detecting an object, comprising:

an inductive sensing coil that is configurable to generate a first magnetic field having a first frequency, the inductive sensing coil configured to have an electrical characteristic that is detectable when generating the first magnetic field, wherein the electrical characteristic is configured to vary as a function of a second time-varying magnetic field simultaneously applied to the object, the second time-varying magnetic field, having a second frequency different than the first frequency, being generated by a wireless power transfer coil independent of the first magnetic field; and

a controller configured to;

detect a change in the electrical characteristic, and

determine a presence of the object based on the detected change in the electrical characteristic.

2. The apparatus of claim 1, wherein the electrical characteristic comprises one or more of an equivalent resistance, an equivalent inductance, an equivalent impedance, and an impulse response of the inductive sensing coil.

3. The apparatus of claim 1, wherein the object comprises one or more of a ferromagnetic object, a metallic film and a metallic foil.

4. The apparatus of claim 1, wherein the inductive sensing coil comprises a plurality of inductive sensing coils and wherein the controller is further configured to multiplex measurements of a plurality of changes in the electrical characteristic of the plurality of inductive sensing coils.

5. The apparatus of claim 1, wherein the second time-varying magnetic field is an alternating magnetic field.

6. The apparatus of claim 1, wherein the controller is configured to detect the change in the electrical characteristic in the time domain.

7. The apparatus of claim 1, wherein the controller is configured to detect the change in the electrical characteristic in the frequency domain.

8. A method for detecting an object, comprising:

detecting a change in an electrical characteristic of an inductive sensing coil, wherein the electrical characteristic is detectable when the inductive sensing coil generates a first magnetic field having a first frequency and the electrical characteristic is configured to vary as a function of a second frequency of a second time-varying magnetic field simultaneously applied to the object, the second time-varying magnetic field being generated by a wireless power transfer coil independent of the first magnetic field; and

determining a presence of the object based on the detected change in the electrical characteristic.

9. The method of claim 8, wherein the electrical characteristic comprises one or more of an equivalent resistance, an equivalent inductance, an equivalent impedance, and an impulse response of the inductive sensing coil.

10. The method of claim 8, wherein the object comprises one or more of a ferromagnetic object, a metallic film and a metallic foil.

11. The method of claim 8, wherein the inductive sensing coil comprises a plurality of inductive sensing coils and the method further comprises multiplexing measurements of a plurality of changes in the electrical characteristic of the plurality of inductive sensing coils.

12. The method of claim 8, wherein the second time-varying magnetic field is an alternating magnetic field.

13. The method of claim 8, further comprising detecting the change in the electrical characteristic in the time domain.

14. The method of claim 8, further comprising detecting the change in the electrical characteristic in the frequency domain.

15. A non-transitory, computer-readable medium comprising code that, when executed, causes an apparatus for detecting an object to:

detect a change in an electrical characteristic of an inductive sensing coil, wherein the electrical characteristic is detectable when the inductive sensing coil generates a first magnetic field having a first frequency and the electrical characteristic is configured to vary as a function of a second time-varying magnetic field simultaneously applied to the object, the second time-varying magnetic field, having a second frequency different than the first frequency, being generated by a wireless power transfer coil independent of the first magnetic field; and

determine a presence of the object based on the detected change in the electrical characteristic.

16. The medium of claim 15, wherein the electrical characteristic comprises one or more of an equivalent resistance, an equivalent inductance, an equivalent impedance, and an impulse response of the inductive sensing coil.

17. The medium of claim 15, wherein the object comprises one or more of a ferromagnetic object, a metallic film and a metallic foil.

18. The medium of claim 15, wherein the inductive sensing coil comprises a plurality of inductive sensing coils and the code, when executed, further causes the apparatus to multiplex measurements of a plurality of changes in the electrical characteristic of the plurality of inductive sensing coils.

19. The medium of claim 15, wherein the second time-varying magnetic field is an alternating magnetic field.

20. The medium of claim 15, wherein the code, when executed, further causes the apparatus to detect the change in the electrical characteristic in the time domain.

21. The medium of claim 15, wherein the code, when executed, further causes the apparatus to detect the change in the electrical characteristic in the frequency domain.

22. An apparatus for detecting an object, comprising:

means for detecting a change in an electrical characteristic of an inductive sensing coil, wherein the electrical characteristic is detectable when the inductive sensing coil generates a first magnetic field having a first frequency and the electrical characteristic is configured to vary as a function of a second time-varying magnetic field simultaneously applied to the object, the second time-varying magnetic field, having a second frequency different than the first frequency, being generated by a wireless power transfer coil independent of the first magnetic field; and

means for determining a presence of the object based on the detected change in the electrical characteristic.

23. The apparatus of claim 22, wherein the electrical characteristic comprises one or more of an equivalent resistance, an equivalent inductance, an equivalent impedance, and an impulse response of the inductive sensing coil.

24. The apparatus of claim 22, wherein the object comprises one or more of a ferromagnetic object, a metallic film and a metallic foil.

25. The apparatus of claim 22, further comprising a plurality of inductive sensing coils including the inductive sensing coil, the apparatus further comprising means for multiplexing measurements of a plurality of changes in the electrical characteristic of the plurality of inductive sensing coils.

26. The apparatus of claim 22, wherein the second time-varying magnetic field is an alternating magnetic field.

27. The apparatus of claim 22, wherein the means for detecting the change in the electrical characteristic detects the change in the time domain.

28. The apparatus of claim 22, wherein the means for detecting the change in the electrical characteristic detects the change in the frequency domain.