Patent ID: 11888337
Assignee: PHILIPS I.P. VENTURES B.V.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 32:
33. A primary circuit comprising:
a tank circuit;
a switching circuit,
wherein the primary circuit is arranged to generate an electromagnetic field,
wherein the primary circuit is arranged to couple to the secondary device using the electromagnetic field,
a sensor for measuring an input characteristic of input power in the primary circuit;
a sensor for measuring a tank characteristic of power in the tank circuit;
a receiver circuit, wherein the receiver circuit is arranged to receive secondary device information from the at least one secondary device;
a controller circuit,
wherein the controller circuit is programmed to estimate power consumption in the primary circuit in combination with the secondary device as a function of at least the tank characteristic;
wherein the controller circuit is programmed to compare the input characteristic, the secondary device information, and the estimated power consumption to determine when there is an unacceptable amount of parasitic metal present in proximity to the primary circuit; and
wherein the controller circuit is programmed to restrict or stop the inductive power transfer from the primary circuit in response to a determination that the unacceptable amount of parasitic metal is present in proximity to the primary circuit.