CONTROLLING INDUCTIVE POWER TRANSFER SYSTEMS
First Claim
1. A method of controlling inductive power transfer in an inductive power transfer system, the system comprising a primary unit operable to generate an electromagnetic field and at least one secondary device, separate from the primary unit, and adapted to couple with said field when the secondary device is in proximity to the primary unit so that power is received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween, the method comprising:
- receiving, in the primary unit, information relating to a power required by the secondary device or devices therefrom;
determining, in the primary unit, in dependence upon the received information the power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices;
measuring a power, and determining that there is a foreign object present in said proximity to the primary unit by detecting a substantial difference between, on the one hand, the measured power and, on the other hand, the required power; and
following such determination of the presence of the foreign object, restricting or stopping the inductive power supply from the primary unit.
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Accused Products
Abstract
An inductive power transfer system (1) comprises a primary unit (10) operable to generate an electromagnetic field and at least one secondary device (30), separable from the primary unit, and adapted to couple with the field when the secondary device is in proximity to the primary unit so that power can be received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween. The system detects if there is a substantial difference between, on the one hand, a power drawn from the primary unit and, on the other hand, a power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices. Following such detection, the system restricts or stops the inductive power supply from the primary unit. Such a system can detect the presence of unwanted parasitic loads in the vicinity of the primary unit reliably.
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Citations
47 Claims
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1. A method of controlling inductive power transfer in an inductive power transfer system, the system comprising a primary unit operable to generate an electromagnetic field and at least one secondary device, separate from the primary unit, and adapted to couple with said field when the secondary device is in proximity to the primary unit so that power is received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween, the method comprising:
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receiving, in the primary unit, information relating to a power required by the secondary device or devices therefrom; determining, in the primary unit, in dependence upon the received information the power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices; measuring a power, and determining that there is a foreign object present in said proximity to the primary unit by detecting a substantial difference between, on the one hand, the measured power and, on the other hand, the required power; and following such determination of the presence of the foreign object, restricting or stopping the inductive power supply from the primary unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. An inductive power transfer system comprising:
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a primary unit operable to generate an electromagnetic field; at least one secondary device, separate from the primary unit, and adapted to couple with said field when the secondary device is in proximity to the primary unit so that power is received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween; means for receiving, in the primary unit, information relating to the power required by the secondary device or devices therefrom; means for determining, in the primary unit, in dependence upon the received information the power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices; power measuring circuitry; means for determining that there is a foreign object present in said proximity to the primary unit by detecting a substantial difference between, on the one hand, the measured power and, on the other hand, the required power; and means operable, following such determination of the presence of the foreign object, to restrict or stop the inductive power supply from the primary unit. - View Dependent Claims (35, 36)
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37. A primary unit, for use in an inductive power transfer system that also has at least one secondary device separate from the primary unit, the primary unit comprising:
- means for generating an electromagnetic field which couples with said at least one secondary device when it is in proximity to the primary unit so that power is received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween;
means for receiving information relating to a power required by the secondary device or devices therefrom; means for determining in dependence upon the received information the power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices; power obtaining circuitry; means for determining that there is a foreign object present in said proximity to the primary unit by detecting a substantial difference between, on the one hand, the obtained power and, on the other hand, the required power; and means operable, following such determination of the presence of the foreign object, to restrict or stop the inductive power supply from the primary unit. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
- means for generating an electromagnetic field which couples with said at least one secondary device when it is in proximity to the primary unit so that power is received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween;
Specification