Resonant wireless power source having coupled resonators oscillating in a single resonant eigenmode
Various embodiments for tuning systems of coupled resonators are described to achieve a desired arrangement of RF current magnitudes and directions, and with a coupled resonant eigenfrequency equal to the desired driving frequency.
1 . A method for wireless power transfer, comprising:
determining a desired magnetic field pattern for generating a wireless power transfer area in which a plurality of receivers may receive power wirelessly;
arranging a plurality of resonators to control a direction and a magnitude of current for each of the plurality of resonators, to generate the desired magnetic field within the wireless power transfer area, wherein
arranging the plurality of resonators is in a loop of segments connected in series, each of the segments comprising a radio frequency (RF) generator;
determining a required tuning of each of the plurality of resonators coupled to one another in the arrangement such that an eigenmode exists with an eigenfrequency equal to a desired driving frequency, and with the direction and the magnitude of the current determined for each of the plurality of resonators being equal to the desired arrangement of current which generates the desired magnetic field pattern; and
providing a wireless power system that generates the desired magnetic field pattern, wherein
providing the wireless power system comprises providing a plurality of conductive loops including at least one inner conductive loop and an outer conductive loop,
the outer conductive loop comprises the loop of segments, each of the segments comprising the RF generator and one or more of the plurality of resonators connected in series by wires, and
the at least one inner conductive loop is also formed as a series of wired connections.
2 . The method of claim 1 , wherein the at least one inner conductive loop is a single inner conductive loop, and a total number of the plurality of conductive loops is two.
3 . The method of claim 1 , wherein providing the wireless power system comprises:
actively driving, using the RF generator of each of the segments, the outer conductive loop as an active resonator; and
passively driving, using the RF generator of each of the segments of the outer conductive loop, the at least one inner conductive loop as a passive resonator.
4 . The method of claim 3 , wherein providing the wireless power transfer system further comprises providing an amplifier and driving the amplifier at an angular resonant frequency of a desired eigenmode.
5 . The method of claim 4 , wherein the amplifier is a Class-E amplifier.
6 . A system for wireless power transfer, comprising:
a wireless power transfer system configured to generate a desired magnetic field pattern within a wireless power transfer area, the wireless power transfer system comprising an amplifier and a plurality of resonators coupled to one another, wherein
the plurality of resonators is in a loop of segments connected in series, each of the segments comprising a radio frequency (RF) generator;
the plurality of resonators is tuned to a required tuning that generates the desired magnetic field pattern, wherein
the required tuning comprises an eigenmode with each of the plurality of resonators having a magnitude and a direction of current that generates the desired magnetic field pattern,
the wireless power transfer system comprises a plurality of conductive loops, the plurality of conductive loops comprising at least one inner conductive loop and an outer conductive loop,
the outer conductive loop comprises the loop of segments, each of the segments comprising the RF generator and one or more of the plurality of resonators connected in series by wires, and
the at least one inner conductive loop is also formed as a series of wired connections.
7 . The system of claim 6 , wherein the at least one inner conductive loop is a single inner conductive loop, a total number of the plurality of conductive loops is two, and the amplifier is a Class-E amplifier.
8 . The system of claim 6 , wherein
the outer conductive loop is actively driven by the RF generator of each of the segments as an active resonator; and
the at least one inner conductive loop is passively driven by the RF generator of each of the segments of the outer conductive loop.
9 . The system of claim 6 , wherein the amplifier is configured to be driven at an eigenfrequency of a desired eigenmode.
10 . The system of claim 6 , wherein the required tuning further comprises a driving frequency determined to be equal to one of a plurality of resonant eigenfrequencies of the arrangement of coupled ones of the plurality of resonators.
11 . The system of claim 6 , wherein the eigenmode is predetermined such that the at least one conductive inner loop carries more current than the-outer conductive loop, thereby amplifying the magnetic field provided by the wireless power transfer system.
12 . The system of claim 10 , wherein RF power sources of the RF generator of each of the segments are phase-locked via a shared local oscillator or injection-locking.