Koninklijke Philips Corporation N.v.

Johannes Wilhelmus Draak

Klaas Jacob Lulofs

Andries Van Wageningen

Pascal Leonard Maria Theodoor Lebens

Wilhelmus Gerardus Maria Ettes

Klaas Jakob Lulofs

A wireless power transmitter () an output circuit () comprises a transmitter coil () for which generates the power transfer signal a drive signal generated by a driver circuit () is applied. A power loop controller () implements a power control loop for controlling the drive signal to adjust a power level of the power transfer signal in response to power control error messages received from the power receiver (). A mode store () stores a plurality of power level modes for the power receiver where each power level mode is associated with a reference power level for the power transfer signal. A mode circuit () adapts the drive signal to set the power level of the power transfer signal to a first reference value in response to receiving a mode request message where the first reference value corresponds to a reference power level for a first power level mode indicated in the mode request message.

Wireless power transfer

A power transmitter () comprises a driver () generating a drive signal for an output resonance circuit comprising transmitter coil () generating a power transfer signal. A resonance detector () determines a coupled resonance frequency for the output resonance circuit during where the coupled resonance frequency is a resonance frequency for the output resonance circuit for the transmitter coil () being coupled to a receiver coil () which is part of a power transfer input resonance circuit of the power receiver (). The input resonance circuit has a quality factor of no less than ten. An estimation circuit () determines a coupling factor estimate for the coupling between the transmitter coil () and the receiver coil () in response to a non-coupled resonance frequency of the output resonance circuit and the first effective resonance frequency. An adapter () sets an operating parameter in response to the coupling factor estimate.

A wireless power transmitter () or power receiver () comprises a power transfer coil () for receiving or generating a power transfer signal and a controller () for controlling the device to perform power transfer during a power transfer phase. The power transfer phase comprises power transfer intervals where power is transferred and foreign object detection time intervals during which a power level of the power transfer signal is reduced. A magnetic shielding element () is positioned between the power transfer coil () and a power transfer coil of a complementary device. The magnetic shielding element () comprises a magnetic shield material having a saturation point such that it operates in a saturated and non-saturated mode during respectively power transfer intervals and foreign object detection time intervals. The saturation point is above a magnetic field strength generated by the power transfer signal during the power transfer time intervals and below that generated during the foreign object detection time intervals.

Device and method for wireless power transfer

A power transmitter comprises a transmitter coil () generating an electromagnetic field. A set of balanced detection coils () comprises detection coils in series and compensating each other. A foreign object detector () performs foreign object detection, by potentially detect a foreign object in response to a property of an output signal from the set of balanced detection coils () in response to the electromagnetic test meeting a foreign object detection criterion. A communicator () is coupled to a communication antenna () communicates with a power receiver () via this. The communication antenna () comprises a plurality of communication coils () coupled in parallel. A first segment of a first communication coil () has a first coupling to a first detection coil and a second segment of a second coil () has a second coupling to a second detection coil. The couplings are capacitive and/or inductive couplings and the first coupling and the second coupling compensate each other in the output signal.

Foreign object detection in a wireless power transfer system

A power transmitter for wirelessly for providing power to a power receiver via an inductive power transfer signal. The power transmitter comprising a power transfer coil for generating the power transfer signal, a driver for generating a drive signal for the power transfer coil, the driver being arranged to, during a power transfer phase, generate the drive signal to employ a repeating time frame comprising at least a power transfer time interval and a transfer foreign object detection time interval, a receiver for receiving a message from the power receiver, a foreign object detector arranged to perform a foreign object detection (FOD) test, a communication coil for generating a communication signal, and a communication unit arranged to generate a communication control signal for the communication coil to provide the communication signal during a communication period, said communication unit being arranged to set the communication control signal to a first value during the communication period and to set the communication control signal to a second value during a communication foreign object detection time interval, the communication foreign object detection time interval occurring during the communication period.

Device and method for wireless power transfer and improved foreign object detection

A device being a power receiver or power transmitter of a wireless power transfer system transfer powers via a power transfer signal: The device comprises power transfer coil () for receiving or generating the power transfer signal and a communication antenna () for communicating with the power receiver () or the power transmitter () via a communication signal. The communication antenna () overlaps the power transfer coil (). A magnetic shielding element () is positioned between the power transfer coil () and the communication antenna (). A controller () controls the device to perform power transfer during power transfer intervals and communication during communication time intervals, the power transfer intervals and communication time intervals being disjoint. The magnetic shielding element () comprises a magnetic shield material arranged to operate in a saturated mode during power transfer intervals and in a non-saturated mode during communication time intervals.

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Horst, Netherlands

Johannes Wilhelmus Draak