Method and apparatus for the alignment of a vehicle and charging coil prior to wireless charging

• US 10,814,729 B2
• Filed: 07/09/2018
• Issued: 10/27/2020
• Est. Priority Date: 11/14/2013
• Status: Active Grant

• Current Assignee: InductEV Inc.
• Original Assignee: Momentum Dynamics Corporation
• Inventors: Long, Bruce Richard, Daga, Andrew W., McMahon, Francis J.
• Primary Examiner(s): Isla, Richard
• Assistant Examiner(s): Hernandez, Manuel
• Application Number:
  US16/030,036
• Publication Number:
  US 20180312071A1
• Time in Patent Office: 841 Days
• Field of Search: 320108, 307104
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• CPC Class Codes: B60L 53/39 with position-responsive activation of primary coils
• CPC Class Codes: B62D 15/028 Guided parking by providing commands to the driver, e.g. acoustically or optically
• CPC Class Codes: B62D 15/0285 Parking performed automatically
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/28 using the near field of leaky cables, e.g. of leaky coaxial cables
• 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

A vehicle alignment system is adapted to align a vehicle with a wireless power induction coil for wireless charging through use of magnetic resonant induction. The system includes a transmission line disposed in the parking slot so as to guide the vehicle to the wireless power induction coil for charging. The transmission line leaks a signal having an operating frequency that is detected to align the vehicle left-right in the parking slot when the vehicle is aligned for charging by the wireless power induction coil. At least two vehicle mounted antennas mounted on opposite sides of transmission line when the vehicle is aligned in the parking slot detect the operating frequency from the transmission line, and signal processing circuitry detects a relative signal phase between signals detected by the antennas. The relative phase differences between the detected signals from the antennas are representative of alignment of the vehicle with respect to the wireless power induction coil and the parking slot.

Claims

1. A vehicle alignment system for aligning a vehicle with a wireless power induction coil in a parking slot for wireless charging through use of magnetic resonant induction, comprising:

a transmission line disposed in the parking slot so as to guide the vehicle to the wireless power induction coil for charging, the transmission line leaking a signal having an operating frequency;

at least two vehicle mounted antennas mounted on opposite sides of the transmission line when the vehicle is aligned in the parking slot, said antennas detecting said signal having said operating frequency that leaks from the transmission line; and

signal processing circuitry that detects a relative signal phase between signals detected by the antennas on opposite sides of the transmission line,

wherein relative phase differences between the detected signals from the antennas are representative of alignment of the vehicle left-right with respect to the transmission line.

2. A system as in claim 1, wherein the transmission line is disposed along a centerline of the parking slot.

3. A system as in claim 2, wherein the vehicle mounted antennas are offset symmetrically from a centerline of the vehicle.

4. A system as in claim 1, wherein the transmission line is parallel to but offset from a center line of the parking slot.

5. A system as in claim 1, wherein the transmission line is curved along a trajectory to guide the vehicle to the wireless power induction coil in the parking slot.

6. A system as in claim 5, wherein the vehicle mounted antennas are offset symmetrically from a centerline of the vehicle.

7. A system as in claim 1, wherein the operating frequency is below 61.5 MHz.

8. A system as in claim 7, wherein the operating frequency is 40.68 MHz.

9. A system as in claim 7, wherein the operating frequency is 13.56 MHz.

10. A system as in claim 1, wherein the signal processing circuitry includes an antenna switch that switches between two or more vehicle mounted antennas.

11. A system as in claim 1, wherein the signal processing circuitry detects a relative signal phase between signals detected by the antennas on opposite sides of the transmission line and determines alignment error polarity and alignment error magnitude when the antennas are not equidistant from the transmission line.

12. A system as in claim 11, further comprising visible, audible, or tactile means for directing a driver to adjust alignment of the vehicle relative to the transmission line in response to said alignment error polarity and said alignment error magnitude.

13. A system as in claim 1, further comprising a continuous wave radio frequency source that provides radio frequency excitation to the transmission line at a power level of about 1 mW.

14. A system as in claim 13, wherein the transmission line comprises a 300-ohm characteristic impedance transmission line.

15. A system as in claim 13, wherein the transmission line comprises a 50 or 75-ohm coaxial cable with slots in outer shielding of the coaxial cable and a termination resistor that is matched to a characteristic impedance of the coaxial cable.

16. A system as in claim 1, wherein the signal processing circuitry comprises:

a frequency modulation receiver for detection of the relative phase differences between the signals detected by the respective antennas, said phase differences induced by sequential switching when the antennas are not an equal distance from the transmission line,

a synchronous detector responsive to antenna switching frequency components present in the output of said frequency modulation receiver,

a voltage comparator that determines alignment error polarity from an output of said synchronous detector, and

an absolute value circuit that determines alignment error magnitude from said output of said synchronous detector.

17. A method for aligning a vehicle with a wireless power induction coil in a parking slot for wireless charging through use of magnetic resonant induction, comprising:

a transmission line disposed in the parking slot leaking a signal having an operating frequency, said transmission line disposed in the parking slot so as to guide the vehicle to the wireless power induction coil for charging;

aligning the vehicle left-right in the parking slot relative to the transmission line for charging by the wireless power induction coil, the aligning comprising at least two vehicle mounted antennas mounted on opposite sides of the transmission line when the vehicle is aligned in the parking slot detecting said signal having said operating frequency that leaks from the transmission line; and

adjusting alignment of the vehicle relative to the wireless power induction coil based on relative phase differences between the detected signals from the antennas as representative of alignment of the vehicle left-right with respect to the transmission line.

18. A method as in claim 17, comprising disposing the transmission line along a curved trajectory to guide the vehicle to the wireless power induction coil in the parking slot.

19. A method as in claim 17, wherein the transmission line leaks the signal through slots in outer shielding of a 50 or 75-ohm coaxial cable.

20. A method as in claim 17, wherein the leaked signal has an operating frequency of 13.56 MHz.

21. A method as in claim 17, wherein the aligning comprises:

a frequency modulation receiver detecting a relative signal phase between signals detected by the antennas on opposite sides of the transmission line, said phase differences induced by sequential switching when the antennas are not an equal distance from the transmission line, wherein said sequential switching includes a synchronous detector responsive to antenna switching frequency components present in the output of said frequency modulation receiver switching between the antennas,

a voltage comparator determining alignment error polarity from an output of said synchronous detector, and

an absolute value circuit determining alignment error magnitude from said output of said synchronous detector.