INDUCTIVE POWER TRANSFER
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Accused Products
Abstract
A detection method for use in a primary unit of an inductive power transfer system, the primary unit being operable to transmit power wirelessly by electromagnetic induction to at least one secondary unit of the system located in proximity to the primary unit and/or to a foreign object located in said proximity, the method comprising: driving the primary unit so that in a driven state the magnitude of an electrical drive signal supplied to one or more primary coils of the primary unit changes from a first value to a second value; assessing the effect of such driving on an electrical characteristic of the primary unit; and detecting in dependence upon the assessed effect the presence of a said secondary unit and/or a foreign object located in proximity to said primary unit.
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Citations
40 Claims
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1-20. -20. (canceled)
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21. A detection method for use in a primary unit of an inductive power transfer system, the primary unit being operable to transmit power wirelessly to a secondary unit in proximity to the primary unit, the secondary unit including a regulator having an operating threshold, the method comprising:
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operating the primary unit in a first driven state by driving one or more coils of the primary unit with a first electrical drive signal sufficient to provide wireless power at or above the operating threshold; obtaining a first measurement of an electrical characteristic of the primary unit in the first driven state; operating the primary unit in a second driven state by driving the one or more coils of the primary unit with a second electrical drive signal sufficient to provide wireless power at or above the operating threshold, wherein the second electrical drive signal is different from the first electrical drive signal; and obtaining a second measurement of the electrical characteristic of the primary unit in the second driven state; determining, based on a comparison between the first measurement and the second measurement, if at least one of the secondary unit and a foreign object is present in proximity to the primary unit, wherein the comparison being consistent with the regulator operating at or above the operating threshold in the first and second driven states is indicative of the secondary unit being present in proximity to the primary unit. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. A primary unit for use in an inductive power transfer system, the primary unit being operable to transmit power wirelessly to a secondary unit located in proximity to the primary unit, the secondary unit having a regulator with an operating threshold, the primary unit comprising:
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drive circuitry operable to drive one or more coils of the primary unit with an electrical drive signal sufficient to provide wireless power at or above the operating threshold of the regulator; control circuitry operably coupled to the drive circuitry, the control circuity programmed to; direct the drive circuitry to operate in a first driven state with the electrical drive signal having a first value sufficient to provide wireless power at or above the operating threshold of the regulator; obtain a first measurement of an electrical characteristic of the primary unit in the first driven state; direct the drive circuitry to operate in a second driven state with the electrical drive signal having a second value sufficient to provide wireless power at or above the operating threshold of the regulator, wherein the first value is different from the second value; obtain a second measurement of the electrical characteristic of the primary unit in the second driven state; and determine, based on a comparison between the first measurement and the second measurement, if at least one of the secondary unit and a foreign object is present in proximity to the primary unit, wherein the comparison being consistent with the regulator operating at or above the operating threshold in the first and second driven states is indicative of the secondary unit being present in proximity to the primary unit. - View Dependent Claims (29, 30, 31, 32, 33)
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34. A method for use in a primary unit of an inductive power transfer system, the primary unit being operable to transmit power wirelessly to a secondary unit located in proximity to the primary unit, the secondary unit including a regulator having an operating threshold, the method comprising:
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operating the primary unit in a first driven state by driving one or more coils of the primary unit with a first electrical drive signal sufficient to provide wireless power to the secondary unit such that the regulator operates at or above the operating threshold; obtaining a first measurement of an electrical characteristic of the primary unit in the first driven state; operating the primary unit in a second driven state by driving the one or more coils of the primary unit with a second electrical drive signal sufficient to provide wireless power to the secondary unit such that the regulator operates at or above the operating threshold, wherein the second electrical drive signal is different from the first electrical drive signal; and determining, based on a comparison between the first measurement and the second measurement, if a foreign object is present in proximity to the primary unit in addition to the secondary unit being present in proximity to the primary unit. - View Dependent Claims (35, 36, 37, 38, 39, 40)
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Specification