METHOD AND APPARATUS FOR ALIGNING A VEHICLE WITH AN INDUCTIVE CHARGING SYSTEM

• US 20150137801A1
• Filed: 09/22/2014
• Published: 05/21/2015
• Est. Priority Date: 08/05/2011
• Status: Active Grant

• Current Assignee: Plugless Power Incorporated
• Original Assignee: Evatran Group, Inc.
• Inventors: Raedy, Steven, Normann, James Brian, Yahnker, Christopher Ryan, Stout, Thomas Gattan II
• Granted Patent: US 9,631,950 B2
• Time in Patent Office: Days
• US Class Current: 324/207.15
• CPC Class Codes: B60L 2240/527 Voltage
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• 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 53/36 by positioning the vehicle
• CPC Class Codes: G01D 5/20 by varying inductance, e.g. by a movable armature
• 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 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• 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
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

A method and apparatus for aligning a vehicle with an inductive charging system is characterized by the addition of alignment coils to a secondary coil on the vehicle. For efficient inductive charging, it is necessary that the vehicle mounted secondary coil be aligned with a stationary primary coil of a transformer of the inductive charging system. When the primary coil is energized, it produces a magnetic field which induces a voltage in the alignment coils as a function of the proximity of the alignment coils to the central axis of the primary coil. The voltage differential between opposed pairs of alignment coils is determined by a comparator which then generates a directional signal which can be used by the operator of the vehicle to position the vehicle for closer alignment of the vehicle secondary coil with the primary coil and more efficient charging.

Claims

1. Apparatus for aligning a vehicle with an inductive charging system, comprising

(a) a transformer including a stationary primary coil and a secondary coil mounted on the vehicle;

(b) at least one alignment coil assembly including a plurality of assembly coils, said alignment coil assembly being arranged in the vicinity of said secondary coil, said primary coil generating a magnetic field when energized to induce a voltage in each assembly coil, respectively, composed of a multi-dimensional measurement proportional to a magnitude of a spacial component of the magnetic field in the direction of the assembly coil axis; and

(c) a controller connected with said alignment coil assembly for generating an output signal corresponding to the voltages induced in said assembly coils which are a function of the position of the vehicle secondary coil relative to the primary coil, whereby the operator of the vehicle can position the vehicle in accordance with the output signal to align said secondary coil with said primary coil.

2. Apparatus as defined in claim 1, wherein said alignment coil assembly comprises a plurality of coils spaced in opposing pairs across an axis of symmetry.

3. Apparatus as defined in claim 2, wherein each coil of said alignment coil assembly is arranged orthogonally to a plane defined by the axes of the other coils of said assembly.

4. Apparatus as defined in claim 3, wherein said controller includes a processor for processing the induced voltages from said assembly coils to produce said output signal which corresponds to the magnetic flux through each alignment coil assembly.

5. Apparatus as defined in claim 3, wherein said controller includes a diode rectifier and low pass filter connected with each assembly coil for measuring the voltage induced therein by said primary coil.

6. Apparatus as defined in claim 5, wherein said diode rectifier and low pass filter for each assembly coil are connected in series to produce an output which approximates the magnetic field amplitude as a sum of the vectors of the multi-dimensional measurement.

7. Apparatus as defined in claim 1, wherein a plurality of alignment coil assemblies are provided, said assemblies being equally spaced in the vicinity of said secondary coil.

8. A method for aligning a vehicle with an inductive charging system including a stationary primary coil and a secondary coil mounted on the vehicle, comprising the steps of

(a) providing a plurality of alignment coils;

(b) energizing the primary coil to generate a magnetic field which induces a voltage in said alignment coils composed of a multi-dimensional measurement proportional to a magnitude of a spacial component of the magnetic field in the direction of the coil axes;

(c) generating an output signal corresponding to the voltages induced in said coils which are a function of the position of the vehicle secondary coil relative to the primary coil, whereby the operator of the vehicle can position the vehicle in accordance with the output signal to align the secondary coil with the primary coil.

9. A method as defined in claim 8, wherein said output signal approximates the magnetic field amplitude as a sum of the vectors of the multi-dimensional measurement.

10. A method for controlling stray electromagnetic fields for a vehicle with an inductive charging system including a stationary primary coil and secondary coil mounted to the vehicle, comprising the steps of

(a) providing sensors for detecting the relative positions of the primary and secondary coils;

(b) providing feedback to the vehicle operator to guide the alignment of the system; and

(c) biasing the feedback to direct the vehicle operator to position the secondary coil within an alignment zone.

11. A method as defined in claim 10, wherein a center of said alignment zone is any point on the vehicle.

12. A method as defined in claim 11, wherein said alignment zone is biased to an area that reduces stray electromagnetic field levels in the proximity of the wireless charger.

13. A method as defined in claim 11, wherein said alignment zone is biased to prevent stray electromagnetic fields from heating metallic components within the vehicle.

14. A method as defined in claim 11, wherein said alignment zone is biased to prevent stray electromagnetic fields from interfering with an electronic system.

15. A method as defined in claim 14, where the electronic system is part of the vehicle.

16. A method for providing feedback to a vehicle operator for an inductive charging system including a stationary primary coil and secondary coil mounted to the vehicle, comprising the steps of

(a) providing sensors for detecting the relative positions of the primary and secondary coils;

and

(b) providing feedback to the vehicle operator to guide the alignment of the system, the feedback being based on the current alignment state which is determined based on the location of a vehicle within one or more alignment zones, the alignment state being further determined by the order in which the vehicle transitions through the one or more alignment zones.

17. A method as defined in claim 16, wherein multiple alignment zones are provided.

18. A method as defined in claim 17, wherein one alignment zone provides feedback to the vehicle operator when the vehicle is correctly aligned.

19. A method as defined in claim 17, wherein one alignment zone maintains the same feedback state as when the zone was entered.

20. A method as defined in claim 17, wherein one alignment zone provides feedback to the vehicle operator when the vehicle is not correctly aligned.

23. A method as defined in claim 17, wherein one alignment zone indicates to the system that power transfer is possible.

24. A method as defined in claim 16, wherein the indication to the vehicle operator to move the vehicle forward comprises a set of scrolling arrows.

25. A method as defined in claim 24, wherein the speed of the scrolling arrows decreases as the distance of the vehicle from proper alignment decreases.

26. A method as defined in claim 16, wherein arrows pointing left, right, forward, and back that are used to provide feedback to the vehicle operator for positioning the vehicle.

27. A method as defined in claim 16, wherein feedback to the vehicle operator shows the location of the vehicle within the alignment zones via a display

21. A method as defined in 20, wherein sub-alignment zones are provided within these zones, each of said sub-alignment zones providing different feedback.

22. A method as defined in claim 21, wherein said sub-alignment zones provide left/right and/or front/back guidance to the vehicle operator.