# US 11,309,736 B2 · Wireless power transfer via electrodynamic coupling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,736 B2 - Document ID: US11309736B2 - Status: Granted - Kind: B2 - Application number: 16/735,437 - Filed: 2020-01-06 - Published: 2020-05-14 - Granted: 2022-04-19 - Earliest claimed: 2010-11-24 - Assignees: University of Florida Research Foundation, Inc. - Applicants: University of Florida Research Foundation, Inc. - Inventors: David Patrick Arnold; Shuo Cheng; Vinod Reddy Challa - Web page: https://patentgrep.com/patent/US11309736B2 ## CPC - H02K 35/02: with moving magnets and stationary coil systems - H02J 50/00: Circuit arrangements or systems for wireless supply or distribution of electric power - H02J 50/001: {Energy harvesting or scavenging} - H02J 50/10: using inductive coupling - H02J 50/12: of the resonant type - H02J 50/50: using additional energy repeaters between transmitting devices and receiving devices - H02J 50/70: involving the reduction of electric, magnetic or electromagnetic leakage fields - H02J 50/90: involving detection or optimisation of position, e.g. alignment - H02K 99/10: {Generators} - H02N 1/08: with conductive charge carrier, i.e. capacitor machines - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Wireless power transmission (WPT) systems are provided. For example, the WPT system can use one or more power transmitting coils and a receiver for electromagnetically coupled wireless power transfer. The electrodynamic receiver can be in the form of an electrodynamic transducer where a magnet is allowed to oscillate near a receiving coil to induce a voltage in the receiving coil, a piezoelectric transducer where the magnet causes a vibrating structure with a piezoelectric layer to move, an electrostatic transducer where movement of the magnet causes a capacitor plate to move, or a combination thereof. An alternating magnetic field from the transmitting coil(s) excites the magnet in the receiver into mechanical resonance. The vibrating magnet then functions similar to an energy harvester to induce voltage/current on an internal coil, piezoelectric material, or variable capacitor. Embodiments utilize magnetic coupling and electromechanical resonance for safe, spatially distributed, low-frequency power delivery to portable devices. ## Claims ### Claim 1 A wireless power transfer system, comprising: a transmitter generating a time-varying external magnetic field; and a receiver generating electrical power under an influence of the time-varying external magnetic field generated by the transmitter, the receiver comprising: an electromechanical conversion element having an axis extending from a fixed end to a distal end, the electromechanical conversion element comprising a piezoelectric material extending along at least a portion of the axis, and a magnet coupled to the distal end of the electromechanical conversion element, where the piezoelectric material generates a voltage in response to a torque exerted on the electromechanical conversion element by the magnet via electrodynamic coupling with the time-varying external magnetic field, wherein the torque produces a rotation of the electromechanical conversion element about the axis of the electromechanical conversion element that generates the voltage of the piezoelectric material. ### Claim 2 (depends on 1) The wireless power transfer system of claim 1, wherein the torque produces a rotational oscillation about the axis of the electromechanical conversion element. ### Claim 3 (depends on 2) The wireless power transfer system of claim 2, wherein the electromechanical conversion element is tuned for operation at a defined resonant frequency. ### Claim 4 (depends on 1) The wireless power transfer system of claim 1, wherein the electromechanical conversion element is formed of the piezoelectric material. ### Claim 5 (depends on 1) The wireless power transfer system of claim 1, wherein the piezoelectric material is disposed on a side of a beam supporting the magnet. ### Claim 6 (depends on 5) The wireless power transfer system of claim 5, wherein the piezoelectric material is a piezoelectric patch. ### Claim 7 (depends on 1) The wireless power transfer system of claim 1, wherein the magnet comprises a permanent magnet. ### Claim 8 (depends on 1) The wireless power transfer system of claim 1, wherein the magnet comprises first and second portions disposed on opposite sides of the electromechanical conversion element. ### Claim 9 (depends on 1) The wireless power transfer system of claim 1, wherein the transmitter comprises a transmitting coil supplied with an alternating current. ### Claim 10 (depends on 1) The wireless power transfer system of claim 1, wherein the electromechanical conversion element comprises a variable capacitor, and the torque produces the rotation of the electromechanical conversion element that causes a time-varying capacitance change in the variable capacitor. ### Claim 11 A method for wireless power transfer, comprising: positioning a receiver adjacent to a transmitter configured to generate a time-varying external magnetic field, the receiver comprising: an electromechanical conversion element having an axis extending from a fixed end to a distal end, the electromechanical conversion element comprising a piezoelectric material extending along at least a portion of the axis, and a magnet coupled to the electromechanical conversion element; and generating a voltage by the piezoelectric material in response to a torque exerted on the electromechanical conversion element by the magnet via electrodynamic coupling with the time-varying external magnetic field generated by the transmitter, wherein the torque produces a rotation of the electromechanical conversion element about the axis of the electromechanical conversion element that generates the voltage of the piezoelectric material. ### Claim 12 (depends on 11) The method of claim 11, wherein the torque produces a rotational oscillation about the axis of the electromechanical conversion element resulting in generation of a time-varying voltage by the piezoelectric material. ### Claim 13 (depends on 11) The method of claim 11, wherein the electromechanical conversion element is formed of the piezoelectric material. ### Claim 14 (depends on 11) The method of claim 11, wherein the piezoelectric material is disposed on a side of a beam supporting the magnet. ### Claim 15 (depends on 11) The method of claim 11, wherein the electromechanical conversion element is tuned for operation at a defined resonant frequency. ### Claim 16 (depends on 15) The method of claim 15, wherein the time-varying external magnetic field is generated at the defined resonant frequency. ### Claim 17 (depends on 15) The method of claim 15, wherein the receiver comprises a second electromechanical conversion element comprising a second piezoelectric material, the second electromechanical conversion element tuned to operation at a second defined resonant frequency. ### Claim 18 (depends on 17) The method of claim 17, wherein a second voltage is generated by the second piezoelectric material of the second electromechanical conversion element in response to electrodynamic coupling with a second external magnetic field.