US 11,742,701 B2
Device and method for wireless power transfer and improved foreign object detection
Johannes Wilhelmus Draak, Limburg (NL)
Assigned to Koninklijke Philips N.V., Eindhoven (NL)
Appl. No. 17/437,857
Filed by KONINKLIJKE PHILIPS N.V., Eindhoven (NL)
PCT Filed Feb. 14, 2020, PCT No. PCT/EP2020/053994
§ 371(c)(1), (2) Date Sep. 10, 2021,
PCT Pub. No. WO2020/187507, PCT Pub. Date Sep. 24, 2020.
Claims priority of application No. 19163757 (EP), filed on Mar. 19, 2019.
Prior Publication US 2022/0173624 A1, Jun. 2, 2022
Int. Cl. H02J 50/60 (2016.01); H02J 50/10 (2016.01); H02J 50/70 (2016.01)
CPC H02J 50/60 (2016.02) [H02J 50/10 (2016.02); H02J 50/70 (2016.02)] 20 Claims
OG exemplary drawing
 
1. A power transmitter for transferring power to a power receiver, the power transmitter comprising:
a first power transfer coil, wherein the first power transfer coil is arranged to generate a power transfer signal;
a controller circuit,
wherein the controller circuit is arranged to control the power transmitter so as to perform power transfer during at least one power transfer phase,
wherein the power transfer phase comprises power transfer intervals and foreign object detection intervals,
wherein power is transferred during the power transfers intervals,
wherein a power level of the power transfer signal is reduced during at least one of the foreign object detection intervals;
a magnetic shielding element,
wherein the magnetic shielding element is positioned between the first power transfer coil and a second power transfer coil,
wherein the second power transfer coil is a portion of the power receiver,
wherein the magnetic shielding element comprises a magnetic shield material,
wherein the magnetic shield material has a saturation point,
wherein the saturation point is arranged such that the magnetic shield material operates in a saturated mode during power transfer intervals and in a non-saturated mode during foreign object detection intervals.