Wireless power transfer using air gap and metamaterial

• US 9,515,492 B2
• Filed: 12/06/2012
• Issued: 12/06/2016
• Est. Priority Date: 12/06/2012
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Nomura, Tsuyoshi, Lee, Jae Seung, Schmalenberg, Paul Donald, Shiozaki, Koji
• Primary Examiner(s): Tran, Thienvu
• Assistant Examiner(s): Comber, Kevin J
• Application Number:
  US13/706,507
• Publication Number:
  US 20140159479A1
• Time in Patent Office: 1,461 Days
• Field of Search: 307/104
• US Class Current: 1/1
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• 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: H01F 27/346 Preventing or reducing leakage fields using magnetic shields H01F27/36; using auxiliary windings H01F27/38
• 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 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

Examples of the invention include methods and apparatus for wirelessly transmitting power to a vehicle using electromagnetic radiation. An example apparatus includes a transmitter coil associated with a first metamaterial lens, and a receiver coil associated with a second metamaterial lens, the receiver coil being located within the vehicle. The metamaterial lenses each have a negative magnetic permeability, and are separated by a lens spacing including an air gap. The first and second metamaterial lenses (and the lens spacing) act cooperatively to focus the electromagnetic radiation from the transmitter coil on the receiver coil.

Claims

1. An apparatus for transmitting power to a vehicle, the apparatus comprising:

a power transmitter, including a transmitter coil and a first metamaterial lens, the power transmitter further including a first electromagnetic mirror; and

a power receiver, including a receiver coil and a second metamaterial lens, the power receiver further including a second electromagnetic mirror, the power receiver being located within the vehicle, the transmitter coil, receiver coil, first metamaterial lens, and the second metamaterial lens being located between the first electromagnetic mirror and the second electromagnetic mirror,

the first and second metamaterial lenses each having a negative magnetic permeability,

the apparatus being operable to transmit electromagnetic radiation from the transmitter coil to the receiver coil when the transmitter coil is energized,

the first metamaterial lens configured to transmit electromagnetic radiation from the transmitter coil onto a focus point, the focus point disposed equidistant between the first and second metamaterial lenses, the electromagnetic radiation transmitting from the focus point so as to be received by the receiver coil.

2. The apparatus of claim 1, the transmitter coil being located within a support surface for the vehicle.

3. The apparatus of claim 1, the power transmitter including an oscillator, the transmitter coil transmitting the electromagnetic radiation when the oscillator is energized.

4. The apparatus of claim 1, the second electromagnetic mirror being located to shield the passenger compartment from the transmitted electromagnetic radiation.

5. The apparatus of claim 1, the negative magnetic permeability of the first and second metamaterial lenses each being −

1, or approximately −

1.

6. The apparatus of claim 1, the second metamaterial lens being disk shaped, the receiver coil being a circular receiver coil having a receiver coil radius, the second metamaterial lens having a radius of at least double the receiver coil radius.

7. The apparatus of claim 6, the radius of the second metamaterial lens being between 0.5 meters and 2 meters.

8. An apparatus for allowing a vehicle to receive transmitted power wirelessly from a power transmitter, the transmitted power being electromagnetic radiation, the apparatus being located in the vehicle, the vehicle including a passenger compartment;

the apparatus including;

a metamaterial lens, the metamaterial lens having a negative magnetic permeability for the electromagnetic radiation;

a receiver coil; and

a pair of electromagnetic mirrors disposed on opposite ends of the metamaterial lenses and on a plane perpendicular to the axis of transmission,

one of the pair of electromagnetic mirrors being located between the receiver coil and the passenger compartment of the vehicle, the electromagnetic mirror protecting the passenger compartment from the electromagnetic radiation and increasing the rate of transmitted power transfer to the receiver coil, wherein the metamaterial lens is configured to transmit the electromagnetic radiation to a focus point disposed equidistant between the pair of mirrors, the electromagnetic radiation transmitting from the focus point so as to be received by the receiver coil.

9. The apparatus of claim 8, the vehicle including a battery,

the power receiver further including an electrical circuit configured to charge the battery when the transmitted power is received by the receiver coil.

10. An apparatus for transmitting power to a vehicle using electromagnetic radiation, the vehicle including a receiver metamaterial lens and a receiver coil, the apparatus comprising:

a power transmitter, the power transmitter including a transmitter coil and a transmitter metamaterial lens, the power transmitter being located outside of the vehicle,

the transmitter coil transmitting power to the vehicle when the transmitter coil is energized and the vehicle is located proximate the power transmitter,

an electromagnetic mirror, located beneath the transmitter coil and the transmitter metamaterial lens when the vehicle is located above the transmitter coil and the transmitter metamaterial lens,

the electromagnetic radiation being transmitted across an air gap between the transmitter metamaterial lens and the vehicle,

the transmitter metamaterial lens having a negative magnetic permeability for the electromagnetic radiation,

the electromagnetic radiation transmitted by transmitter metamaterial lens being focused on to a focus point disposed equidistant between the transmitter metamaterial lens and the receiver metamaterial lens, the electromagnetic radiation transmitting from the focus point so as to be received by the receiver coil within the vehicle by the combined action of the transmitter metamaterial lens and the receiver metamaterial lens.

11. The apparatus of claim 10, the negative magnetic permeability of the transmitter metamaterial lens is approximately −

1.

12. The apparatus of claim 10, the transmitter coil being located within a parking space for the vehicle.