Wireless Power Transfer System, Power Transfer Apparatus, and Power Reception Apparatus

• US 20120056485A1
• Filed: 08/03/2011
• Published: 03/08/2012
• Est. Priority Date: 09/07/2010
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Haruyama, Hideaki
• Granted Patent: US 9,124,114 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries

Abstract

According to one embodiment, a wireless power transfer system performs electrical power transfer and signal communication by magnetic field resonance. A power transfer apparatus includes a first resonator configured to resonate at a predetermined frequency and to switch a Q-factor between high and low, and a first controller configured to set the Q-factor of the first resonator high in the electrical power transfer, and to set the Q-factor of the first resonator low in the signal communication. The power reception apparatus includes a second resonator configured to resonate at the predetermined frequency and to switch a Q-factor between high and low, and a second controller configured to set the Q-factor of the second resonator high when performing the electrical power transfer and to set the Q-factor of the second resonator low when performing the signal communication.

Claims

1. A wireless power transfer system configured to perform electrical power transfer and signal communication by magnetic field resonance between a power transfer apparatus and a power reception apparatus in a time-division manner,

wherein the power transfer apparatus comprises:

a first resonator configured to resonate at a predetermined frequency and to switch a Q-factor between high and low; and

a first controller configured to set the Q-factor of the first resonator high when performing the electrical power transfer, and to set the Q-factor of the first resonator low when performing the signal communication, and

wherein the power reception apparatus comprises;

a second resonator configured to resonate at the predetermined frequency and to switch a Q-factor between high and low; and

a second controller configured to set the Q-factor of the second resonator high when performing the electrical power transfer and to set the Q-factor of the second resonator low when performing the signal communication.

2. The system of claim 1,

wherein the first controller is configured to transfer the electrical power comprising authentication-free electrical power and authentication electrical power, to transfer the authentication-free electrical power at a predetermined interval, and to transfer the authentication electrical power to an power reception apparatus which is authenticated by the signal communication and whose allocated period has checked by the signal communication, and

wherein the second controller is configured to receive the authentication-free electrical power without authentication and to receive the authentication electrical power reception after authentication and check of an allocated period by the signal communication.

3. The system of claim 2,

wherein the power reception apparatus further comprises:

a load module to which a received authentication electrical power is supplied; and

an authentication-free power detection module configured to detect transfer of the authentication-free electrical power, and to become active when detecting the transfer of the authentication-free electrical power, and

wherein the second controller is configured to receive the authentication electrical power in the allocated period and to supply received power to the load module, and to disconnect the load module in a period other than the allocated period.

4. The system of claim 3,

wherein the first controller is configured to transfer the authentication-free electrical power and the authentication electrical power in a continuous burst state, and

the authentication-free power detection module is configured to detect a start timing of the continuous burst state in order to detect a start timing of the transfer of the authentication-free electrical power.

5. The system of claim 4,

wherein the first controller is configured to allocate transfer periods of the authentication electrical power to power reception apparatuses in a time-division manner, to notify the power reception apparatuses of allocated transfer periods by the signal communication, to transfer, in a continuous burst state, the authentication electrical power in allocated transfer periods and the authentication-free electrical power, to reallocate the transfer periods of the authentication electrical power so that the continuous burst state continues further when one of the power reception apparatuses has finished receiving the authentication electrical power, and to notify the power reception apparatuses of reallocated transfer periods by the signal communication, and

wherein the second controller is configured to receive the authentication electrical power in the allocated transfer periods notified by the signal communication.

6. The system of claim 2, wherein the first controller is configured to display a list of power reception apparatuses checked by the authentication.

7. The system of claim 2, wherein the second controller is configured to monitor a power reception level while performing reception of the authentication electrical power and to adjust a resonant frequency so that the power reception level is maximized by varying a variable capacitor of the second resonator.

8. The system of claim 7, wherein the variable capacitor comprises a piezoelectric resin whose capacitance varies with a voltage change by applying a voltage between terminals.

9. A power transfer apparatus for a wireless power transfer system configured to perform electrical power transfer and signal communication by magnetic field resonance between the power transfer apparatus and a power reception apparatus in a time-division manner, the power transfer apparatus comprising:

a resonator configured to resonate at a resonant frequency and to switch a Q-factor between high and low; and

a controller configured to set the Q-factor of the resonator high when performing an electrical power transfer, and to set the Q-factor of the resonator low when performing a communication.

10. The power transfer apparatus of claim 9,

wherein the controller is configured to transfer the electrical power comprising authentication-free electrical power and authentication electrical power, to transfer the authentication-free electrical power at a predetermined interval, and to transfer the authentication electrical power to an power reception apparatus which is authenticated by the signal communication and whose allocated period has checked by the signal communication.

11. The power transfer apparatus of claim 10,

wherein the controller is configured to transfer the authentication-free electrical power and the authentication electrical power in a continuous burst state.

12. The power transfer apparatus of claim 11,

wherein the controller is configured to allocate transfer periods of the authentication electrical power to power reception apparatuses in a time-division manner, to notify the power reception apparatuses of allocated transfer periods by the signal communication, to transfer, in a continuous burst state, the authentication electrical power in allocated transfer periods and the authentication-free electrical power, to reallocate the transfer periods of the authentication electrical power so that the continuous burst state continues further when one of the power reception apparatuses has finished receiving the authentication electrical power, and to notify the power reception apparatuses of reallocated transfer periods by the signal communication.

13. The power transfer apparatus of claim 9, wherein the resonator comprises a variable capacitor configured to change the resonant frequency, the variable capacitor comprising a piezoelectric resin whose capacitance varies with a voltage change by applying a voltage between terminals.

14. A power reception apparatus for a wireless power transfer system configured to perform electrical power transfer and signal communication by magnetic field resonance between a power transfer apparatus and the power reception apparatus in a time-division manner, the power reception apparatus comprising:

a resonator configured to resonate at a resonant frequency and to switch a Q-factor between high and low; and

a controller configured to set the Q-factor of the resonator high when performing an electrical power reception, and to set the Q-factor of the resonator low when performing a communication.

15. The power reception apparatus of claim 14,

wherein the controller is configured to receive the electrical power comprising authentication-free electrical power and authentication electrical power, to receive the authentication-free electrical power at a predetermined interval, and to receive the authentication electrical power from an power transfer apparatus which is authenticated by the signal communication and whose allocated period has checked by the signal communication.

16. The power reception apparatus of claim 15, further comprising:

a load module to which the authentication electrical power is supplied; and

an authentication-free power detection module configured to detect the authentication-free electrical power being transferred by the authentication-free power transfer, and to become active when detecting the authentication-free electrical power being transferred, and

wherein the controller is configured to receive the authentication electrical power in the allocated period of the authentication electrical power transfer, to supply the authentication electrical power to the load module, and to disconnect the load module in a period other than the allocated period of the authentication electrical power transfer.

17. The power reception apparatus of claim 16, wherein the authentication-free power detection module is configured to detect a continuous burst state and to regard the timing of a rising of the continuous burst state as a start timing of the authentication-free electrical power transfer.

18. The power reception apparatus of claim 17, wherein the controller is configured to receive notification from the power transfer apparatus to power reception apparatuses by the communication, the notification indicating an allocated period of the authentication power transfer, to perform the authentication electrical power reception in the allocated period.

19. The power reception apparatus of claim 15, wherein the controller is configured to monitor a power reception level while performing the authentication electrical power reception and to adjust a resonant frequency so that the power reception level is maximized by varying a variable capacitor of the second resonator.

20. The power reception apparatus of claim 19, wherein the variable capacitor comprises a piezoelectric resin whose capacitance varies with a voltage change by applying a voltage between terminals.