Omnidirectional wireless power transfer system
In one example, an omnidirectional wireless power transfer system includes high frequency power generator configured to generate a supply of high frequency oscillating power, a number of transmitter-side resonant tank circuits electrically coupled to the high frequency power generator, a receptacle including a number of coils arranged for omnidirectional power transfer to an electronic device placed in the receptacle, and a controller configured to activate individual ones of the transmitter-side resonant tank circuits to wirelessly transmit power to the electronic device through near-field resonant inductive coupling. In one example, the receptacle can be embodied as a bowl, and the controller can activate individual ones of the transmitter-side resonant tank circuits over time to generate an omnidirectional field distribution for wireless power transmission. In other aspects, various transmitter-side and receiver-side tank circuits for coupling independent resonance and ZVS operation are described.
1. An omnidirectional wireless power transfer system, comprising:
a plurality of resonant tank circuits electrically coupled to a power generator;
a receptacle comprising a plurality of coils arranged for omnidirectional power transfer to an electronic device placed with the receptacle, each of the plurality of coils being electrically coupled to one of the plurality of resonant tank circuits; and
a controller configured to activate individual ones of the resonant tank circuits with different voltages or currents to wirelessly transmit power through one or more of the plurality of coils to provide omnidirectional power transfer to the electronic device.
2. The omnidirectional wireless power transfer system according to claim 1 , wherein:
the receptacle comprises a bowl having the plurality of coils arranged in or on side and bottom surfaces of the bowl; and
the plurality of coils are arranged to provide multidirectional magnetic field distribution.
3. The omnidirectional wireless power transfer system according to claim 2 , wherein the controller is further configured to activate individual ones of the resonant tank circuits with different voltages or currents over time to generate omnidirectional field distribution over the surfaces of the receptacle.
4. The omnidirectional wireless power transfer system according to claim 2 , wherein the controller is further configured to activate individual ones of the resonant tank circuits with different voltages or currents over time to generate omnidirectional field distribution over the bottom surfaces.
5. The omnidirectional wireless power transfer system according to claim 1 , wherein the controller is further configured to sense a level of power transferred to the electronic device by individual ones of the plurality of resonant tank circuits to identify a coefficient of power transfer between individual ones of the plurality of resonant tank circuits and the electronic device.
6. The omnidirectional wireless power transfer system according to claim 1 , wherein the controller is further configured to modulate a supply of power provided to individual ones of the plurality of resonant tank circuits in at least one of amplitude or phase to generate an omnidirectional field distribution.
7. The omnidirectional wireless power transfer system according to claim 1 , wherein the plurality of resonant tank circuits each comprises at least one resonant converter topology for coupling independent resonance and zero voltage switching (ZVS).
8. The omnidirectional wireless power transfer system according to claim 1 , further comprising:
the electronic device, the electronic device comprising a receiver-side resonant tank circuit for near-field resonant inductive coupling with one or more of the plurality of resonant tank circuits and one or more of the plurality of coils.
9. The omnidirectional wireless power transfer system according to claim 8 , wherein at least one of the plurality of resonant tank circuits and the receiver-side resonant tank circuit each comprises a resonant converter topology for coupling independent resonance and zero voltage switching (ZVS).
10. The omnidirectional wireless power transfer system according to claim 8 , wherein the at least one of the plurality of resonant tank circuits and the receiver-side resonant tank circuit exhibit gain characteristics comprising one series resonance frequency positioned between two parallel resonant frequencies.
11. The omnidirectional wireless power transfer system according to claim 8 , wherein the at least one of the plurality of resonant tank circuits comprises a CLCL resonant converter topology, and the receiver-side resonant tank circuit comprises an LC resonant converter topology.
12. The omnidirectional wireless power transfer system according to claim 8 , wherein the at least one of the plurality of resonant tank circuits and the receiver-side resonant tank circuit comprise at least one of a LCCL-LC, LC-LCCL, CLCL-LC, or LCCL-LCL resonant converter topology.
13. A resonant circuit with coupling independent resonance and zero voltage switching characteristics, comprising:
a parallel resonant cell;
a zero voltage switching branch; and
a series resonant cell.
14. The resonant circuit according to claim 13 , wherein the parallel resonant cell and the series resonant cell form a coupling independent resonance for system operation.
15. The resonant circuit according to claim 13 , wherein the zero voltage switching branch ensures a primary switching device achieves zero voltage switching at a coupling independent resonant frequency.
16. The resonant circuit according to claim 13 , wherein the parallel resonant cell provides constant current characteristics for a transmitter coil.
17. The resonant circuit according to claim 13 , wherein, in gain characteristics, the resonant circuit includes one coupling independent series resonant frequency and two parallel resonant frequencies.
18. The resonant circuit according to claim 17 , wherein, in gain characteristics, the series resonant frequency is between the two parallel resonant frequencies.
19. The resonant circuit according to claim 17 , wherein the resonant circuit is not limited to wireless power transfer applications but can also be used in other variable coupling applications.