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1. EP2985846 - Wireless power transmission

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Claims

1. A wireless electrical power receiver, comprising:

a receiver resonator arranged to inductively generate an AC electrical current;

a rectifier connected to the receiver resonator to receive and convert the AC electrical current from the receiver resonator into DC electrical power;

a load arranged to receive DC electrical power from the rectifier;

a switching arrangement to selectively provide a short circuit to retain the AC electrical current within the receiver resonator when the switch is operated; and

a controller configured to supply a control signal to operate the switching arrangement to control the AC electrical current supplied to the rectifier.


  2. The wireless electrical power receiver of claim 1, wherein the controller is further configured to supply the control signal to operate the switching arrangement to provide the short circuit when the AC electrical current in the receiver resonator passes through zero.
  3. The wireless electrical power receiver of claim 2, wherein the controller is further configured to remove the control signal to cause the switching arrangement to remove the short circuit based on the amount of DC power required by the load.
  4. The wireless electrical power receiver of claim 1, wherein the rectifier is an active rectifier which comprises a plurality of electrically operable switches and wherein the controller is further configured to supply rectification control signals to the plurality of electrically operable switches to control rectification of the AC electrical current into DC electrical power.
  5. The wireless electrical power receiver of claim 4, wherein the switching arrangement comprises one or more of the plurality of electrically operable switches of the rectifier.
  6. The wireless electrical power receiver of claim 5, wherein the rectifier has a full wave bridge topology.
  7. The wireless electrical power receiver of claim 6, wherein the controller is further configured to supply the control signal to operate the switching arrangement to provide the short circuit each time the AC electrical current in the receiver resonator passes through zero.
  8. The wireless electrical power receiver of claim 5, wherein the rectifier has a Greinacher voltage doubler topology.
  9. The wireless electrical power receiver of claim 8, wherein the controller is further configured to supply the control signal to operate the switching arrangement to provide the short circuit every other time the AC electrical current in the receiver resonator passes through zero.
  10. The wireless electrical power receiver of claim 1, wherein the rectifier has a voltage doubler topology.
  11. The wireless electrical power receiver of claim 10, wherein the switching arrangement comprises a pair of transistors connected in anti-series
  12. The wireless electrical power receiver of any preceding claim, wherein the rectifier has a rectifier topology and the rectifier topology provides impedance matching between the receiver resonator and the load and no other impedance matching network is included in the wireless electrical power receiver.
  13. The wireless electrical power receiver of any preceding claim, and further comprising a DC-DC converter arranged between the rectifier and the load to receive DC electrical power from the rectifier and to supply converted DC electrical power to the load.
  14. An electrical device including a wireless power receiver as claimed in any preceding claim and wherein the load is a re-chargeable battery.
  15. A method for extracting DC electrical power from an induced AC electrical signal, the method comprising:

rectifying an AC electrical current produced by induction by a receiver resonator into DC electrical power; and

periodically short circuiting the receiver resonator to retain the AC electrical current within the receiver resonator.