Device and method for wireless power transfer

A method of operation of a power transmitter device for wireless power transfer from a power transmitter to a power receiver using an power transfer signal,

• wherein the power transfer signal during a power transfer phase uses at least one repeating frame(s),
• wherein the at least one repeating time frame(s) comprise at least one power transfer interval(s) and at least one object detection interval(s),
• wherein a power limit of the power transfer signal is lower for the at least one object detection interval(s) than for the power transfer time interval,
• wherein the power transmitter device comprises a communication resonance circuit
• wherein the communication resonance circuit comprises a communication antenna and a power transfer circuit,
• wherein the communication antenna is arranged to transmit and receive a communication signal,
• wherein the power transfer circuit comprises a power transfer coil, the method comprising:
• generating the power transfer signal during the at least one power transfer interval(s) using the power transfer coil;
• communicating with a power receiver via an communication signal;
• controlling the communication resonance circuit to provide a resonance at a first resonance frequency to the communicator circuit;
• and
• adapting the communication resonance circuit to not provide the resonance at the first resonance frequency to the communicator circuit during the at least one object detection interval(s).

A power receiver device comprising:

• a power transfer circuit,
• wherein the power transfer circuit comprises a power transfer coil,
• wherein the power transfer coil is arranged to receive a power transfer signal during at least one power transfer interval(s),
• wherein the at least one power transfer interval(s) is a portion of at least one repeating frame(s),
• wherein the at least one repeating frame(s) comprises the at least one power transfer interval(s) and at least one object detection interval(s);
• a communicator circuit, wherein the communicator circuit is arranged to communicate with a power transmitter via a communication signal;
• a communication resonance circuit,
• wherein the communication resonance circuit comprising a communication antenna,
• wherein the communication antenna is arranged to transmit and receive the communication signal,
• wherein the communication resonance circuit is arranged to provide a resonance at a first resonance frequency for the communicator circuit;
• and
• a controller circuit, wherein the controller circuit is arranged to adapt the communication resonance circuit to not provide the resonance for the communicator circuit during the at least one object detection interval(s).

A method of operation of a power receiver device for wireless power transfer from a power transmitter to a power receiver using an power transfer signal,

• wherein the power transfer signal during a power transfer phase uses at least one repeating frame(s),
• wherein the at least one repeating time frame(s) comprise at least one power transfer interval(s) and at least one object detection interval(s),
• wherein a power limit of the power transfer signal is lower for the at least one object detection interval(s) than for the power transfer time interval,
• wherein the power receiver device comprises a communication resonance circuit,
• wherein the communication resonance circuit comprises a communication antenna and a power transfer circuit,
• wherein the communication antenna is arranged to transmit and receive a communication signal,
• wherein the power transfer circuit comprises a power transfer coil, the method comprising:
• receiving the power transfer signal during the at least one power transfer interval(s) using the power transfer coil;
• communicating with a power receiver via an communication signal;
• controlling the communication resonance circuit to provide a resonance at a first resonance frequency to the communicator circuit;
• and
• adapting the communication resonance circuit to not provide the resonance at the first resonance frequency to the communicator circuit during the at least one object detection interval(s).