CONTROLLING INDUCTIVE POWER TRANSFER SYSTEMS
First Claim
1. A secondary device, for use in an inductive power transfer system that comprises a primary unit which generates an electromagnetic field, the secondary device comprising:
- a secondary coil adapted to couple with said field generated by said primary unit 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;
a load connection unit, connected to said secondary coil and adapted to be connected when the secondary device is in use to a load requiring power from the primary unit, for supplying such inductively-received power to the load; and
a communication unit operable to communicate to the primary unit information relating to a parasitic load imposed on the primary unit by the secondary device.
1 Assignment
0 Petitions
Accused Products
Abstract
An inductive power transfer system comprises a primary unit, having a primary coil and an electrical drive unit which applies electrical drive signals to the primary coil so as to generate an electromagnetic field. The system also comprises at least one secondary device, separable from the primary unit and having a secondary coil which couples with the field when the secondary device is in proximity to the primary unit. A control unit causes a circuit including said primary coil to operate, during a measurement period, in an undriven resonating condition. In this condition the application of the drive signals to the primary coil by the electrical drive unit is suspended so that energy stored in the circuit decays over the course of the period. A decay measurement unit takes one or more measures of such energy decay during the measurement period. In dependence upon said one or more energy decay measures, the control unit controls the electrical drive unit so as to restrict or stop inductive power transfer from the primary unit.
-
Citations
20 Claims
-
1. A secondary device, for use in an inductive power transfer system that comprises a primary unit which generates an electromagnetic field, the secondary device comprising:
-
a secondary coil adapted to couple with said field generated by said primary unit 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; a load connection unit, connected to said secondary coil and adapted to be connected when the secondary device is in use to a load requiring power from the primary unit, for supplying such inductively-received power to the load; and a communication unit operable to communicate to the primary unit information relating to a parasitic load imposed on the primary unit by the secondary device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A portable electrical or electronic device comprising:
-
a load which at least at times requires power from said primary unit; and a secondary device comprising; a secondary coil adapted to couple with said field generated by said primary unit 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; a load connection unit, connected to said secondary coil and adapted to be connected when the secondary device is in use to a load requiring power from the primary unit, for supplying such inductively-received power to the load; and a communication unit operable to communicate to the primary unit information relating to a parasitic load imposed on the primary unit by the secondary device; wherein said load connection unit of said secondary device is connected to said load for supplying such inductively-received power to the load at said times. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
-
-
18. A method of controlling inductive power transfer in an inductive power transfer system comprising a primary unit, having a primary coil to which electrical drive signals are applied to generate an electromagnetic field, and also comprising at least one secondary device, separable from the primary unit and having friendly parasitics and a secondary coil adapted to couple with said field when the secondary device is in proximity to the primary unit so that power can be transferred inductively from the primary unit to the secondary device without direct electrical conductive contacts therebetween, which method comprises:
-
receiving in the primary unit from the secondary device information indicative of the friendly parasitics of the secondary device; detecting in the primary unit whether a substantial parasitic load is present in proximity to the primary unit, said detecting taking into consideration the information indicative of the friendly parasitics received in the primary unit; and restricting or stopping inductive power transfer from the primary unit in dependence upon said detecting step. - View Dependent Claims (19, 20)
-
Specification