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 the 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:
- measuring, in the secondary device or devices therefrom, a characteristic of a secondary power being supplied to a load of the secondary device;
receiving, in the primary unit, power requirement information of the secondary device or devices therefrom, the power requirement information includes information relating to the measured characteristic of the secondary power;
determining, in the primary unit, in dependence upon the power requirement information of the secondary device a power supplied to the secondary device or, if there is more than one secondary device, a combined power supplied to the secondary devices;
measuring a primary power drawn from the primary unit, and determining if there is a substantial difference between, on the one hand, the measured primary power and, on the other hand, the power supplied; and
following such determination of a substantial difference, restricting or stopping the inductive power supply from the primary unit.
2 Assignments
0 Petitions
Accused Products
Abstract
An inductive power transfer system comprises a primary unit operable to generate an electromagnetic field and at least one secondary device, 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
34 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 the 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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measuring, in the secondary device or devices therefrom, a characteristic of a secondary power being supplied to a load of the secondary device; receiving, in the primary unit, power requirement information of the secondary device or devices therefrom, the power requirement information includes information relating to the measured characteristic of the secondary power; determining, in the primary unit, in dependence upon the power requirement information of the secondary device a power supplied to the secondary device or, if there is more than one secondary device, a combined power supplied to the secondary devices; measuring a primary power drawn from the primary unit, and determining if there is a substantial difference between, on the one hand, the measured primary power and, on the other hand, the power supplied; and following such determination of a substantial difference, 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)
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15. 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 the 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; a load-measuring unit for determining information relating to a power requirement of the secondary device or devices therefrom; communication circuitry for receiving, in the primary unit, the power requirement of the secondary device or devices therefrom; power measuring circuitry; and a control unit for determining if there is a substantial difference between, on the one hand, the measured power and, on the other hand, the power requirement, and the control unit operable, following such determination of a substantial difference, to restrict or stop the inductive power supply from the primary unit. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. 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:
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a primary coil for generating an electromagnetic field which couples with the 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; communication circuitry for receiving information relating to a power requirement of the secondary device or devices therefrom; power obtaining circuitry for obtaining a power drawn from the primary unit; and a control unit for determining in dependence upon the received information a power supplied to the secondary device or, if there is more than one secondary device, a combined power supplied to the secondary devices, the control unit for determining if there is a substantial difference between, on the one hand, the obtained power and, on the other hand, the supplied power, and the control unit operable, following such determination of a substantial difference, to restrict or stop the inductive power supply from the primary unit. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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29. A secondary unit, for use in an inductive power transfer system that also has a primary unit, said secondary unit comprising:
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a secondary coil adapted to couple with a field generated from said primary unit when in proximity to said primary unit so that power is received inductively by said secondary unit without direct electrical conductive contacts therebetween; a load-measuring unit for determining information relating to a power requirement of said secondary unit; and communication circuitry for sending said power requirement to said primary unit, and said communication circuitry varying a load to communicate said power requirement to said primary unit. - View Dependent Claims (30, 31, 32, 33, 34)
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Specification