Wireless power transmission method

• US 9,490,064 B2
• Filed: 07/27/2012
• Issued: 11/08/2016
• Est. Priority Date: 07/28/2011
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Hirosawa, Atsushi, Nakagawa, Tomoaki
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Pham, Duc M
• Application Number:
  US14/131,214
• Publication Number:
  US 20140145516A1
• Time in Patent Office: 1,565 Days
• Field of Search: 307/104
• US Class Current: 1/1
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/00716 in response to integrated charge or discharge current
• 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

Abstract

A wireless power transmission method transmits power from a first resonance antenna to a second resonance antenna in a noncontact manner through resonance of a magnetic field. The first resonance antenna is a resonance antenna of a power transmitting device, the second resonance antenna is a resonance antenna of a power receiving device. The wireless power transmission method includes setting a first transmission efficiency between the first resonance antenna and the second resonance antenna by changing a frequency of supply power of the power transmitting device. Power transmitted from the first resonance antenna to the second resonance antenna is gradually increased. A resonance frequency is changed by changing an induction coefficient or electrostatic capacity of the second resonance antenna to change the transmission efficiency between the first and second resonance antenna to a second transmission efficiency smaller than the first transmission efficiency, thereby matching received power to required power.

Claims

1. A wireless power transmission method that transmits power from a first resonance antenna to a second resonance antenna in a noncontact manner through resonance of a magnetic field, the first resonance antenna being a resonance antenna of a power transmitting device, the second resonance antenna being a resonance antenna of a power receiving device, the wireless power transmission method comprising the steps of:

setting transmission efficiency between the first resonance antenna and the second resonance antenna as first transmission efficiency by changing a frequency of supply power of the power transmitting device;

gradually increasing power transmitted from the first resonance antenna to the second resonance antenna; and

changing a resonance frequency by a change of at least one of an induction coefficient and electrostatic capacity of the second resonance antenna to change the transmission efficiency between the first resonance antenna and the second resonance antenna to second transmission efficiency smaller than the first transmission efficiency, thereby matching received power to required power of the power receiving device.

2. The wireless power transmission method according to claim 1,

wherein the power transmitting device monitors the transmission efficiency between the first resonance antenna and the second resonance antenna and estimates the required power on the basis of the change in the transmission efficiency.

3. The wireless power transmission method according to claim 2,

wherein the power transmitting device changes transmission power so as to become equal to the estimated required power, and

the power receiving device changes the resonance frequency by a change of at least one of the induction coefficient and the electrostatic capacity of the second resonance antenna such that the received power becomes equal to the required power, thereby changing the transmission efficiency between the first resonance antenna and the second resonance antenna to third transmission efficiency greater than the second transmission efficiency.