Frequency changing encoded resonant power transfer

• US 10,084,343 B2
• Filed: 06/13/2014
• Issued: 09/25/2018
• Est. Priority Date: 06/13/2014
• Status: Active Grant

• Current Assignee: Empire Technology Development LLC (Allied Inventors Management, LLC)
• Original Assignee: Empire Technology Development LLC (Allied Inventors Management, LLC)
• Inventors: Fine, Kevin S.
• Primary Examiner(s): Fleming, Fritz M
• Application Number:
  US14/304,653
• Publication Number:
  US 20150364923A1
• Time in Patent Office: 1,565 Days
• CPC Class Codes: H02J 50/12 of the resonant type

Abstract

Systems and methods to for wireless power transfer are provided. A transmit control module generates a sequence of resonant drive frequencies for a transmit coil. The transmit control module adjusts the resonant frequency of the transmit coil according to the sequence of resonant drive frequencies. A receive control module provides payment verification to the transmit control module and receives the sequence of resonant drive frequencies from the transmit control module in return. The receive control module adjusts a resonant frequency of a receive coil according to the sequence of resonant drive frequencies to match the resonant frequency of the transmit coil. The resonant frequencies of the transmit and receive coils change at the same time to maintain coupling and efficient power transfer.

Claims

1. A system to provide wireless power transfer to one or more mobile devices, the system comprising:

a transmit coil that is configured to generate an electromagnetic signal that induces a current in one or more receive coils of the one or more mobile devices to provide power to the one or more mobile devices; and

a control module that is communicatively coupled to the transmit coil and to the one or more mobile devices, wherein the control module is configured to;

generate a sequence of resonant drive frequencies, wherein the generated sequence of resonant drive frequencies includes a number of frequencies that vary in a number of cycles,

generate a pseudorandom number that falls within a particular frequency index,

select a resonant drive frequency, from among the generated sequence of resonant drive frequencies, of the transmit coil that corresponds to the particular frequency index, and

provide the generated sequence of resonant drive frequencies to the one or more mobile devices to allow the one or more receive coils of the one or more mobile devices to be driven by substantially same resonant drive frequency as the selected resonant drive frequency of the transmit coil.

2. The system of claim 1, wherein the control module is communicatively coupled to the one or more mobile devices over a network and is configured to provide the generated sequence of resonant drive frequencies to the one or more mobile devices over the network.

3. The system of claim 1, wherein the control module is further configured to receive payment verification information that indicates that a form of payment has been received from at least one of the one or more mobile devices, and wherein the control module provides the generated sequence of resonant drive frequencies to the at least one of the one or more mobile devices that provided the payment verification information.

4. The system of claim 1, wherein the transmit coil is located in a public location and is configured to induce the current in the one or more mobile devices that are located in the public location.

5. The system of claim 1, wherein the transmit coil is configured to operate in a frequency range between 1 to 50 MHz and is configured to transmit between 0 W and 100 W of transmit power.

6. The system of claim 1, further comprising:

a reactive element that is electrically coupled to the transmit coil; and

a frequency generator,

wherein the reactive element is configured to be adjusted by the control module in accordance with the generated sequence of resonant drive frequencies to change the selected resonant drive frequency at which the transmit coil transmits, and

wherein the frequency generator drives the transmit coil with the selected resonant drive frequency.

7. The system of claim 6, wherein the reactive element is one of an adjustable inductance or capacitance.

8. The system of claim 1, wherein the control module is configured to adjust the selected resonant drive frequency of the transmit coil at one or more of a zero crossing of current or at a zero crossing of voltage, after a random number of cycles, or after a random amount of time.

9. The system of claim 1, wherein a counter and an encryption key are used to generate the sequence of resonant drive frequencies, wherein the counter and the encryption key are associated with the particular frequency index that specifies each of the resonant drive frequencies in the generated sequence that are to be used during a specific time period, and

wherein the counter and the encryption key are provided to the one or more mobile devices so that the one or more mobile devices use the particular frequency index to determine which specific resonant drive frequency of the generated sequence to use at the specific time period.

10. A method to provide wireless power transfer to one or more mobile devices, the method comprising:

generating a sequence of resonant drive frequencies for a transmit coil, wherein the generated sequence of resonant drive frequencies includes a number of frequencies that vary in a number of cycles;

generating a first pseudorandom number that falls within a first frequency index;

selecting a first resonant drive frequency, from among the generated sequence of resonant drive frequencies, of the transmit coil that corresponds to the first frequency index;

transmitting, by the transmit coil, an electromagnetic signal at the first resonant drive frequency to one or more receive coils of the one or more mobile devices, the electromagnetic signal inducing a current in the one or more receive coils to provide power to the one or more mobile devices, the one or more receive coils operating at a first resonant receive frequency that is equivalent to the first resonant drive frequency;

generating a second pseudorandom number that falls within a second frequency index;

selecting a second resonant drive frequency, from among the generated sequence of resonant drive frequencies, of the transmit coil that corresponds to the second frequency index;

adjusting the first resonant drive frequency of the transmit coil to the second resonant drive frequency in accordance with the generated sequence of resonant drive frequencies; and

providing the generated sequence of resonant drive frequencies to the one or more mobile devices to allow a resonant receive frequency of the one or more receive coils of the one or more mobile devices to adjust from the first resonant receive frequency to a second resonant receive frequency that is equivalent to the second resonant drive frequency at substantially same time the transmit coil adjusts from the first resonant drive frequency to the second resonant drive frequency.

11. The method of claim 10, wherein adjusting the first resonant drive frequency of the transmit coil to the second resonant drive frequency in accordance with the generated sequence of resonant drive frequencies comprises one or more of:

adjusting a reactive element that is electrically coupled to the transmit coil, adjusting a frequency at which a frequency generator drives the transmit coil, adjusting a resonant drive frequency of the transmit coil at a zero crossing of current or at a zero crossing of voltage, adjusting the resonant drive frequency of the transmit coil after a random number of cycles, or adjusting the resonant drive frequency of the transmit coil after a random amount of time.

12. A system for a mobile device to receive wireless power transfer, the system comprising:

a receive coil that is configured to receive an electromagnetic signal from a transmit coil, wherein the electromagnetic signal, generated by the transmit coil, is configured to induce a current in the receive coil; and

a control module that is communicatively coupled to the receive coil and to a transmit module that controls the transmit coil, wherein the control module is configured to;

receive, from the transmit module, a sequence of resonant drive frequencies for the transmit coil, wherein the received sequence of resonant drive frequencies includes a number of frequencies that vary in a number of cycles, wherein a selected resonant drive frequency, from among the sequence of resonant drive frequencies, is received from the transmit module, and wherein the selected resonant drive frequency is generated, by the transmit module, based on a pseudorandom number that falls within a particular frequency index, and

adjust a resonant receive frequency of the receive coil in accordance with the received sequence of resonant drive frequencies so that the resonant receive frequency of the receive coil matches the selected resonant drive frequency of the transmit coil.

13. The system of claim 12, wherein the control module is coupled to the transmit module over a network and is configured to receive the sequence of resonant drive frequencies from the transmit module over the network.

14. The system of claim 12, wherein the control module is further configured to provide payment verification information to the transmit module prior to the receipt of the sequence of resonant drive frequencies, and wherein the sequence of resonant drive frequencies is received in response to provision of the payment verification information.

15. The system of claim 12, wherein the receive coil is configured to receive the electromagnetic signal from the transmit coil in a public location where the transmit coil has been installed.

16. The system of claim 12, further comprising:

a reactive element that is electrically coupled to the receive coil; and

a frequency generator,

wherein the reactive element is configured to be adjusted by the control module in accordance with the received sequence of resonant drive frequencies to change the resonant receive frequency at which the receive coil receives the electromagnetic signal, and

wherein the frequency generator drives the receive coil with the resonant receive frequency.

17. The system of claim 16, wherein the reactive element is one of an adjustable inductance or capacitance.

18. The system of claim 12, wherein the control module is configured to adjust the resonant receive frequency of the receive coil after:

a random number of cycles or a random amount of time.

19. The system of claim 12, wherein a counter and an encryption key are used to generate the sequence of resonant drive frequencies, wherein the counter and the encryption key are associated with the particular frequency index that specifies each of the resonant drive frequencies in the generated sequence that are to be used during a specific time period, and

wherein the counter and the encryption key are received by the control module from the transmit module so that the control module uses the particular frequency index to determine which specific resonant drive frequency of the generated sequence to use at the specific time period.

20. A method for a mobile device to receive wireless power transfer, the method comprising:

receiving a sequence of resonant drive frequencies for a transmit coil from a transmit module that controls the transmit coil, wherein the received sequence of resonant drive frequencies includes a number of frequencies that vary in a number of cycles;

receiving, at a receive coil of the mobile device that is operating at a first resonant receive frequency that is equivalent to a first resonant drive frequency of the transmit coil, a first electromagnetic signal from the transmit coil transmitted at the first resonant drive frequency, wherein the first resonant drive frequency is selected, from among the received sequence of resonant drive frequencies, by the transmit module, wherein the first resonant drive frequency is generated by the transmit module based on a first pseudorandom number that falls within a first frequency index, and wherein the electromagnetic signal induces a current in the receive coil to provide power to the mobile device; and

adjusting the first resonant receive frequency of the receive coil to a second resonant receive frequency in accordance with the received sequence of resonant drive frequencies so that the receive coil is able to receive a second electromagnetic signal from the transmit coil transmitted at a second resonant drive frequency, the second resonant receive frequency being equivalent to the second resonant drive frequency, wherein the second resonant drive frequency is selected, from among the sequence of resonant drive frequencies, by the transmit module, and wherein the second resonant drive frequency is generated by the transmit module based on a second pseudorandom number that falls within a second frequency index.

21. The method of claim 20, wherein adjusting the first resonant drive frequency of the receive coil to the second resonant receive frequency in accordance with the received sequence of resonant drive frequencies comprises one or more of:

adjusting a reactive element that is electrically coupled to the receive coil, adjusting a frequency at which a frequency generator drives the receive coil, adjusting a resonant receive frequency of the receive coil at a zero crossing of current or at a zero crossing of voltage, adjusting the resonant receive frequency of the receive coil after a random number of cycles, or adjusting the resonant receive frequency of the receive coil after a random amount of time.