Wireless power supply system and wireless power supply method

• US 8,519,569 B2
• Filed: 03/11/2010
• Issued: 08/27/2013
• Est. Priority Date: 03/30/2009
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Shimokawa, Satoshi
• Primary Examiner(s): AMAYA, CARLOS DAVID
• Application Number:
  US12/721,770
• Publication Number:
  US 20100244577A1
• Time in Patent Office: 1,265 Days
• Field of Search: 307/9.1, 307/10.1, 307/104
• US Class Current: 307/104
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60L 53/305 Communication interfaces
• CPC Class Codes: B60L 53/39 with position-responsive activation of primary coils
• 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: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

A wireless power supply apparatus includes: a transmitting coil configured to transmit power in the form of magnetic field energy using magnetic resonance; and a power transmitter configured to supply power at a resonant frequency that produces magnetic resonance between the transmitting coil and a receiving coil; wherein the power transmitter includes a detector configured to detect current flowing into the transmitting coil, a controller configured to control the frequency of the power supplied to the transmitting coil, and a determining unit configured to determine the coupling strength between the transmitting coil and the receiving coil on the basis of the frequency of the current detected by the detector as well as the frequency of the supplied power.

Claims

1. A wireless power supply system, comprising:

a transmitting coil configured to transmit power in a form of magnetic field energy using magnetic resonance; and

a power transmitter configured to supply power at a resonant frequency that produces magnetic resonance between the transmitting coil and a receiving coil;

wherein the power transmitter includes a detector configured to detect current flowing into the transmitting coil, a controller configured to control the frequency of the power supplied to the transmitting coil, and a determining unit configured to detect an amplitude of the current detected by the detector on a basis of a frequency of the current detected by the detector and determine a coupling strength between the transmitting coil and the receiving coil on the basis of the amplitude.

2. The wireless power supply system according to claim 1, wherein the controller sweeps the frequency of the power supplied to the transmitting coil, and the determining unit determines the coupling strength between the transmitting coil and the receiving coil on the basis of a frequency characteristics of the amplitude of the current flowing into the transmitting coil as detected by the detector.

3. The wireless power supply system according to claim 1, wherein the controller sweeps the frequency of the power supplied to the transmitting coil, and the determining unit determines the coupling strength between the transmitting coil and the receiving coil on the basis of a frequency characteristics of the phase between the current flowing into the transmitting coil as detected by the detector, and the power supplied to the transmitting coil.

4. The wireless power supply system according to claim 1, wherein on the basis of the determination results of the determining unit, the power transmitter outputs a command signal to an apparatus provided in the receiving coil.

10. The wireless power supply system according to claim 1, wherein the determining unit configured to detect a peak amplitude of the detected current as the amplitude and determines the coupling strength on the basis of the peak amplitude.

5. A wireless power supply system, comprising:

a transmitting coil configured to transmit power in the form of magnetic field energy using magnetic resonance;

a receiving coil configured to receive the magnetic field energy transmitted from the transmitting coil, and convert the received energy into power; and

a power transmitter configured to supply power at a resonant frequency that produces magnetic resonance between the transmitting coil and the receiving coil;

wherein the power transmitter includes a detector configured to detect current flowing into the transmitting coil, a controller configured to control the frequency of the power supplied to the transmitting coil, and a determining unit configured to detect an amplitude of the current detected by the detector on a basis of a frequency of the current detected by the detector and determine a coupling strength between the transmitting coil and the receiving coil on the basis of the amplitude.

6. The wireless power supply system according to claim 5, wherein the controller sweeps the frequency of the power supplied to the transmitting coil, and the determining unit determines the coupling strength between the transmitting coil and the receiving coil on the basis of the frequency characteristics of the amplitude of the current flowing into the transmitting coil as detected by the detector.

7. The wireless power supply system according to claim 5, wherein the controller sweeps the frequency of the power supplied to the transmitting coil, and the determining unit determines the coupling strength between the transmitting coil and the receiving coil on the basis of the frequency characteristics of the phase between the current flowing into the transmitting coil as detected by the detector, and the power supplied to the transmitting coil.

8. The wireless power supply system according to claim 5, wherein on the basis of the determination results of the determining unit, the power transmitter outputs a command signal to an apparatus provided in the receiving coil.

11. The wireless power supply system according to claim 5, wherein the determining unit configured to detect a peak amplitude of the detected current as the amplitude and determines the coupling strength on the basis of the peak amplitude.

9. A wireless power supply method, comprising:

transmitting power from a transmitting coil in the form of magnetic field energy using magnetic resonance;

supplying power at a resonant frequency that produces magnetic resonance between the transmitting coil and a receiving coil;

detecting current flowing into the transmitting coil;

detecting an amplitude of the detected current on a basis of a frequency of the detected current;

determining a coupling strength between the transmitting coil and the receiving coil on the basis of the amplitude.

12. The wireless power supply method according to claim 9, wherein a peak amplitude of the detected current is detected as the amplitude and the coupling strength is determined on the basis of the peak amplitude.