GB2500691A

GB2500691A - Charging system for a vehicle

Info

Publication number: GB2500691A
Application number: GB1205652.9A
Authority: GB
Inventors: David White; Jeremy Greenwood; Chris Clarke; Richard Parkins
Original assignee: Jaguar Cars Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2012-03-30
Filing date: 2012-03-30
Publication date: 2013-10-02
Anticipated expiration: 2032-03-30
Also published as: GB201205652D0; GB2500691B

Abstract

A system and method of automatically aligning a vehicle 10 with an inductive charging station 8 in which one or more sensors or cameras 20 are coupled to a controller which thereby recognises a charging station and calculates a route to align the vehicle with the charging station so as to optimise the coupling efficiency between the vehicle and the charging station. The controller directs the vehicle to autonomously position the vehicle in an optimum position for charging a battery 12.

Description

tM:;: INTELLECTUAL S... * PROPERTY OFFICE Application No. tJB1205652.9 RTM Date:13 July 2012 The following terms are registered trademarks and should be read as such wherever they occur in this document: Bluetooth Intellectual Properly Office is an operaling name of Ihe Patent Office www.ipo.gov.uk

CHARGING SYSTEM FOR A VEHICLE

TECHNICAL FIELD

The present invention relates to a charging system for a vehicle and a method of charging a vehicle battery and particularly, but not exclusively, to a method and system for aligning a wireless power receiver with a wireless power transmitter. Aspects of the invention relate to a system, to a vehicle, to an electric vehicle and to a method.

BACKGROUND

It is known to provide vehicles with a traction battery for propulsion of the vehicle when coupled to an electric drive motor, such traction batteries require charging. It is desirable to wirelessly couple the vehicle to a charging station; to avoid the need for connectors and to provide an improved customer experience, such systems may employ inductive coupling to charge the traction battery.

In order to optimise coupling efficiency it is desirable to optimise the alignment of the vehicle's transceiver with the transceiver of the charging station.

It is against this background that the present invention has been conceived. Embodiments of the invention may provide an improvement in the field of inductive charging systems that has particular application for vehicles. The invention may be utilised in applications other than for vehicles, for example it is foreseen that the invention may have application in buildings for example robotics or other autonomous vehicles. Other aims and advantages of the invention will become apparent from the following description, claims and drawings.

SUMMARY

Aspects of the invention provide a system, a vehicle, to an electric vehicle and a method as claimed in the appended claims.

According to one aspect of the invention for which protection is sought, there is provided a system for a vehicle for automatically aligning a vehicle with a charging station, the system comprising: a coupling device for coupling to a coupling device of a charging station; one or more sensors for detecting the charging station; and a control unit configured to receive data from said one or more sensors, wherein the control unit is configured to calculate a route to the charging station so as to align the vehicle with the charging station and is configured to instruct one or more vehicle control systems to direct the vehicle to a position in which the coupling device of the vehicle is coupleable to the coupling device of the charging station.

Optionally, the system is wireless and the coupling device of the charging station comprises a wireless power transceiver; the coupling device of the vehicle comprises a wireless power transceiver for coupling to the wireless power transceiver of the charging station one or more sensors for detecting the wireless power transceiver of the charging station; and wherein the control unit is configured to calculate a route to the charging station so as to align the wireless power transceiver of the vehicle with the wireless power transceiver of the charging station and is configured to instruct one or more vehicle control systems to direct the vehicle to a position in which the wireless power transceiver of the vehicle is in alignment with the wireless power transceiver of the charging station.

Optionally, the control unit may interface with one or more vehicle control systems selected from the group consisting of: electric power assisted steering system; automatic transmission system; electronic throttle control system; electric drive system; braking system; and vehicle suspension system.

Optionally, the control unit may comprise a predefined search pattern for movement of the wireless power transceiver of the vehicle with respect to the wireless transceiver of the charging station so as to optimise the coupling efficiency therebetween.

Additionally, or alternatively the control unit may be coupled to a measurement device for measuring the coupling efficiency between the wireless power transceiver of the vehicle and the wireless power transceiver of the charging station, and the control unit may comprise a storing device for storing the measured data and the relative position of the wireless power transceiver of the vehicle with respect to the wireless power transceiver of the charging station.

Optionally, the control unit may be configured to move a vehicle and/or wireless power transceiver of the vehicle with respect to the wireless power transceiver of the charging station by searching for the maximum coupling efficiency between the wireless power transceiver of the vehicle and the wireless power transceiver of the charging station.

Optionally, the control unit comprises an image recognition system for automatically recognising a charging station. The control unit may comprise a database of images of charging stations. Optionally, the database is updateable by a vehicle operator.

The image recognition system may recognise one or more optical targets or alignment aids which optical target or alignment aids facilitate calculation of a route to the charging station by the control unit.

According to another aspect of the invention for which protection is sought, there is provided a vehicle comprising the system of as described in the foregoing paragraphs.

According to yet another aspect of the invention for which protection is sought, there is provided an electric vehicle having a traction battery for propulsion of the vehicle as described in the foregoing paragraphs.

According to a further aspect of the invention for which protection is sought, there is provided a method for aligning a vehicle with a charging station, the method comprising: detecting or recognisinçj a charging station via one or more sensors mounted to the vehicle; calculating a route between the vehicle's current position and that of the charging station so as to bring a the vehicle into alignment with the charging station; and instructing one or more vehicle control systems to manoeuvre the vehicle such that the vehicle is aligned with the charging station.

In some embodiments the vehicle is wirelessly coupled to the charging station and the sensors detect or recognise a wireless power transceiver of the charging station and the method may comprise: calculating a route between the vehicle's current position and that of the charging station so as to bring a wireless power transceiver of the vehicle into alignment with the wireless power transceiver of the charging station; and instructing one or more vehicle control systems to manoeuvre the vehicle such that the wireless transceiver of the vehicle is aligned with the wireless transceiver of the charging station.

Optionally, the method comprises measuring the coupling efficiency between the wireless transceiver of the vehicle and the wireless transceiver of the charging station.

Optionally, the method comprises storing the coupling efficiency and position of the wireless transceiver of the vehicle with respect to the wireless transceiver of the charging station in a memory device coupled to a control unit and mounted to the vehicle.

Optionally, instructing one or more vehicle control systems comprises instructing one or more vehicle systems to manoeuvre the vehicle and thereby the wireless transceiver of the vehicle with respect to the wireless transceiver of the charging station in a predefined search pattern.

Optionally, the method comprises storing the optimum position of the wireless transceiver of the vehicle with respect to the wireless transceiver of any given charging station visited by the vehicle.

Optionally, the method comprises recognising a charging station previously visited by the vehicle and recalling the optimum position of the wireless transceiver of the vehicle with respect to the wireless transceiver of the recognised charging station, and directing the vehicle so as to position the wireless transceiver of the vehicle in said optimum position.

The method may comprise comparing an image or data received from the vehicle sensors with an image or data stored in a database of images of known charging stations.

Optionally, the method comprises matching an image or data received from the vehicle sensors of an observed charging station with an image or data stored in a database of images of known charging stations and recalling alignment data of the observed charging station for calculation of a route to the observed charging station by the control unit.

Within the scope of this application it is envisaged that the various aspects, embodiments, examples and alternatives, and in particular the features thereof, set out in the preceding paragraphs, in the claims and/or in the following description and drawings, may be taken independently or in any combination thereof. For example, features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is a schematic view of a vehicle approaching a charging station according to an embodiment of the invention; FIGURE 2 is a schematic illustration of a system of the vehicle of Figure 1; FIGURE 3 is a schematic view of the vehicle of Figure 1 in which the transceiver of the charging station and transceiver of the vehicle are aligned; and FIGURE 4 is a schematic view of the vehicle of Figure 3 in which the vehicle body has been lowered over the charging station.

DETAILED DESCRIPTION OF EMBODIMENTS

Detailed descriptions of specific embodiments of the system for wirelessly charging, the methods, and vehicles of the present invention are disclosed herein. It will be understood as that the disclosed embodiments are merely examples of the way in which certain aspects of the invention can be implemented and do not represent an exhaustive list of all of the ways the invention may be embodied. Indeed, it will be understood that the system for wirelessly charging, the methods, and vehicles described herein may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimised to show details of particular components. Well-known components, materials or methods are not necessarily described in great detail in order to avoid obscuring the present disclosure. Any specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the invention.

Figure 1 illustrates a vehicle 10 comprising a traction battery 12 coupled to an electric drive motor (not shown) for providing propulsion to the vehicle 10.

Vehicle 10 may optionally comprise an internal combustion engine (not shown) for providing additional propulsion to the vehicle 10. Traction battery 12 is charged using a charging system 9. In some embodiments the traction battery 12 may also be charged by supplementary means such as regenerative braking.

Vehicle 10 comprises a first wireless power receiver 14, for example a first coil 14 connected to control unit 15 which is then coupled to the traction battery 12. Control unit 15 will comprise electronic circuitry including rectifiers which will convert the AC from the first coil 14 to DC to be used by the traction battery 12.

First coil 14 is mounted to the underside of the body 11 of the vehicle 10. In alternative embodiments alternative locations are envisaged for example, the first wireless power receiver may be mounted to the front or rear bumpers, behind the front grille, on or within a body panel of the vehicle 10.

The charging system 9 comprises the first coil 14 mounted to the vehicle 10 and a second wireless power transmitter 16, for example a second coil 16, located externally and remotely from the vehicle 10 at a charging stationS. In the illustrated embodiment the second coil 16 is disposed at ground level beneath the vehicle 10. In other embodiments the second coil 16 could be located in, and/or on a wall or post. Second coil 16 is coupled to a control unit 18 which is coupled to a power supply such as mains electricity supply and together form the charging station 8.

A varying electrical current, such as an alternating current (AC), is passed through the second coil 16, creating a varying magnetic field F. The presence of first coil 14 in the varying magnetic field F induces a varying electromotive force (voltage) in the first coil 14. As such the first coil 14 is inductively coupled to the second coil 16. A load is coupled in the first coil 14, thus causing electrical current to flow in the first coil 14. The first coil 14 is inductively coupled to the second coil 16, when the first and second coils 14, 16 are sufficiently aligned with one another and whilst varying electrical current is passed through the second coil 16. The current induced in the first coil 14 can be utilised to charge or recharge the traction battery 12. In order to maximise charging efficiency the first and second coils 14, 16 are optionally substantially spatially aligned, in this arrangement vertically aligned. The physical alignment (also referred to as spatial alignment) will be dependent upon the shape and distribution of the varying magnetic field F generated by the second coil 16. It is envisaged that in alternative embodiments the maximum charging efficiency may be achieved by optimising the coupling efficiency between the first coil 14 and the second coil 16 in which the physical alignment of the first coil 14 with respect to the second coil 16 may be dependent upon the electro-magnetic field operated by the second coil 16, which in turn may be dependent upon the shape and configuration of the second coil 16.

In this embodiment the first coil 14 acts as a receiver and the second coil 16 acts as a transmitter such that power is transferred from the charging station 8 to the vehicle 10. In other embodiments power may be transferred to the charging station 8 from the vehicle 10, for example to discharge the battery 12 for storage or maintenance; in such embodiments the first coil 14 acts as a transmitter and the second coil 16 acts as a receiver.

The vehicle 10 comprises a control unit 15 coupled to the first coil 14. The control unit 15 is capable of communicating with the charging station & via the first coil 14, for example by modulating a signal on an electric current in the first coil 14, such that the charging station 8 can determine that the vehicle 10 is a legitimate tiansceiver of energy from the charging station 8. In alternative embodiments an alternative communications system may be utilised employing a radio, optical or other wireless communications link such as but not limited to Bluetooth, Wi-Fi (IEEE 802.11), NEC, CARS, EDGE, 3G UMIS, HSAA, 4G LIE, IrDA (Infrared Data Association). The control unit 15 may also be configured to instruct the charging system 9 to shut down or reduce the charging rate when the battery 12 has attained a predefined state of charge. Alternatively, by terminating current flow in the second coil 16, the control unit 15 may electrically disconnect the first coil 14 from the traction battery 12 to prevent overcharging or overheating.

Vehicle 10 also comprises a sensor 20. (It is envisaged that more than one sensor 20 may be distributed about the vehicle 10. Sensor 20 is capable of detecting the presence of the charging station 8, and may for example be a camera, infra-red sensor or ultrasonic parking distance control (PDC) sensor. Additionally or alternatively other systems may be employed including but not limited to Radar, Light Detection and Ranging (Lidar), GPS. In some embodiments a plurality of sensor types may be employed and other suitable sensor types may be employed.

In Figure 1 the vehicle 10 is located at a distance from a charging station 8. The first coil 14 is not inductively coupled to the second coil 16; no charging of the traction battery 12 is taking place.

Sensors 20 form part of an automated alignment system 7, shown in Figure 2, which automated alignment system 7 is employed to automate the alignment of the vehicle 10 when the charging station 8 to determine and locate an optimum position in which the charging rate of the traction battery 12 may be optimised or maximised by optimising or maximising the coupling efficiency between the first coil 14 and the second coil 16.

The automated alignment systeni 7 is configured to detect and/or recognise a charging station 8 and is configured to position the vehicle 10 above or otherwise relative to the

S

second coil 16 of the charging station 8, such that the second coil 16 is aligned with the first wireless receiver 14 on the vehicle 10.

Automated alignment system 7 comprises a control unit 22 coupled to the sensors 20.

Control unit 22 is also coupled to a charging controller 15 which in turn is coupled to both the first coil 14 and traction battery 12. In alternative embodiments (shown in dashed lines) control unit 22 is coupled to the first coil l4and to the traction battery 12.

Control unit 22 is also coupled to vehicle control systems 24, 26, 28. In the illustrated embodiment the vehicle control system 24 is an electric power steering system (ERAS); vehicle control system 26 is an automatic transmission system; vehicle control system 27 is a braking system and vehicle control system 28 is an electronic throttle control system or electric drive system.

Control unit 22 is also coupled to a human machine interface (HMI) system 30 including an in-cabin display. HMI system 30 may comprise input means such as a touch screen for receiving input commands from the driver. Alternatively, the HMI system may comprise output means such as a display screen for sending output commands to the driver, for example to manoeuvre the vehicle manually so as to position the first and second coils in substantial alignment with one another.

The control unit 22 comprises a database of images of charging stations or other indicia indicative of a charging station, the database may be pre-programmed or may be updated or added to by a user via the HMI image recognition. It is envisaged that the charging station will comprise a logo, alignment marking or other optical target to facilitate recognition and/or alignment of the vehicle with the charging station, the control unit 22 is capable of recognising, for example with image recognition software, such optical targets as charging stations and calculating a route or course for the vehicle in order to place the first coil 14 in alignment with the second coil 16.

Control unit 22 may also be coupled to a vehicle suspension system 32. Suspension system 32 being capable of adjusting the ride height of the vehicle body 11 with respect to ground level, for example by raising or lowering the vehicle body 11 using compressed air or other suitable means such as a hydraulic system or other mechanical system.

The control unit 22 receives data from the sensor 20 and/or from the HMI system 30, indicating the location of a charging station 8.

It is envisaged that the charging station 8 comprises an indicia and/or alignment aid which may be identified automatically by the control unit 22 via input data received from the sensor 20. Alternatively, the identity or location of the charging station 8 may be input, optionally by a user via the display of the HMI system 30.

The control unit 22 having identified a charging station and/or otherwise determined the location of the charging station 8 from the data received is configured to plot a course (also referred to as route) to the charging station 8, taking into account any obstructions which may have been detected. The control unit 22 is configured to instruct the electronic power steering system, automatic transmission system and throttle control system or electric drive system to manoeuvre and direct the vehicle 10 to the charging station 8. In some embodiments the driver retains control over the selection of transmission gear and throttle or electric drive system whilst the control unit 22 interfaces with the electric power steering system. The system 22 may issue alerts to the driver for example, if input from the sensors indicates that a collision may occur. In other embodiments the control unit 22 may control or restrict vehicle speed. In all embodiments the driver may override instructions given by the control unit 22 and assume full control of the vehicle 10.

Once the vehicle 10 has been brought into close proximity to the charging station 8 as shown in Figure 2, the alignment system 7 may refine the alignment of the vehicle 10, in particular, the alignment system 7 may refine the alignment and positioning of the first coil 14, (which receives electrical power from the charging station 8), relative to (optionally above) the second coil 16.

The control unit 22 is configured to monitor the coupling efficiency between the first wireless receiver 14 and the second wireless transmitter 16. This may be achieved for example, by measuring the magnitude of the current flow induced in the first coil 14. In other embodiments the control unit 22 may measure an alternative electrical characteristic of the first and/or second coils 14, 16 to monitor the inductive coupling efficiency. For example the control unit 22 may measure voltage across the first coil 14; and/or the control unit 22 may measure or calculate the mutual inductance between the first and second coils 14, 16.

The control unit 22 in co-operation with the automated alignment system 7 may cause the vehicle 10 to move in a predetermined search pattern in the locality or proximate the second coil 16 of the charging station 8, for example, in a rastered grid search; or spiral search; over the second coil 16 seeking the optimum coupling efficiency between the first and second coils 14, 16.

The automated alignment system 7 moves the vehicle 10 relative to, optionally over the charging station 8, monitoring the coupling strength between the first and second coils 14, 16. The automated alignment system 7 may record the coupling strength optionally, by monitoring the electrical current induced in the first coil 14; and record the position of vehicle 10. In this way the automated alignment system 7 can build up a map of the charging efficiency at different locations over the charging station 8 and determine the optimum position. During a manoeuvring sequence to determine a relative positioning between the vehicle 10 and charging station 8 the coupling efficiency may be continuously or intermittently recorded against position, optionally in a stored data array to enable the control unit 22 to identify which relative position, out of all of the relative positions scanned yields the maximum coupling efficiency.

Alternatively, the system 7 may only record the highest charging efficiency/coupling strength and the respective location, replacing the recorded data each time a better location is discovered.

In some embodiments the system 7 may record the optimum position found for any given charging station 7 for future use, such that the system may return the vehicle 10 to that position without further searching. In such embodiments, if at a subsequent visit to a charging station where an optimum coupling efficiency location has been determined, a check of the coupling efficiency is reduced. The control unit 22 may automatically initiate a subsequent search for an optimum position or suggest (via the HMI) that the driver initiates such a subsequent search. Alternatively, the control unit 22 periodically may automatically initiate a subsequent search or periodically may suggest that the driver manually initiate a subsequent calibration search.

Further it is envisaged that the system 7 may carry out the search pattern over any particular charging station 8 over a plurality of separate lists or charge cycles. For example, if the charging station 8 is visited regularly, such as a home station, workplace station or other frequently visited location. The system 7 may align the vehicle 10 with the charging station 8, aligning differently each time the charging station 8 is used, thereby building up a picture of the optimum alignment of the vehicle 10 with respect to the charging station 8 over a period of visits. In such a configuration, it is envisaged that optionally, if at a subsequent visit to a known charging station a different alignment location is selected wherein the coupling efficiency is lower than a previously detected coupling location, the automated alignment system 7 may automatically re-adjust the vehicle's position to the previous best location".

It is envisaged that the vehicle body 11 will be lowered over the charging station once the system 7 has determined the particular location at which any given charge cycle is to be carried out. In alternative embodiments the vehicle body 11 may be lowered, at least partially, before conducting a fine alignment search.

The control unit 22 is in communication with the suspension system 32 of the vehicle 10 and may lower the vehicle body 11 to bring the first coil 14 into closer proximity to the second coil 16, as shown in Figure 4, thereby increasing the coupling efficiency between the first and second coils 14, 16.

It can be appreciated that various changes may be made within the scope of the present invention, for example, in other embodiments of the invention it is envisaged that the charging station may transmit a signal to the vehicle to facilitate alignment of the vehicle with the charging station.

In alternative embodiments of the invention; the system is employed to align a plug and socket assembly to allow for direct coupling between the vehicle and the mains electricity supply, such systems may communicate using a wired connection utilising a wired communications protocol such as Ethernet, TCP/IP or other suitable protocol. In a wired configuration the system may use the wired mains power connection for communications between the vehicle and charging station using a power line communications system by impressing a modulated carrier signal on the wiring system.

In those embodiments in which the vehicle may transfer power to the charging system as well as receive power from the charging station, the vehicle may be provided with both a transmitter and receiver, which may be implemented as a transceiver mounted upon the vehicle similarly the charging station may be provided with both a transmitter and receiver, which may be implemented as a transceiver.

Claims

CLAIMSA system for automatically aligning a vehicle with a charging station, the system comprising: a coupling device for coupling to a coupling device of the charging station; one or more sensors for detecting the charging station; and a control unit configured to receive data from said one or more sensors, wherein the control unit is configured to instruct one or more vehicle control systems to direct the vehicle to a position in which the coupling device of the vehicle is coupleable to the coupling device of the charging station.
2. The system according to claim 1, wherein the system is wireless and the coupling device of a charging station comprises a wireless power transceiver, the coupling device of the vehicle comprises a wireless power transceiver for coupling to the wireless power transceiver of the charging station; and wherein the control unit is configured to calculate a route to the charging station so as to align the wireless power transceiver of the vehicle with the wireless power transceiver of the charging station and is configured to instruct one or more vehicle control systems to direct the vehicle to a position in which the wireless power transceiver of the vehicle is in alignment with the wireless power transceiver of the charging station.
3. The system according to either of claims 1 or 2 wherein the control unit may interface with one or more vehicle control systems selected from the group consisting of: electric power assisted steering system; automatic transmission system; electronic throttle control system; electric drive system; braking system; and vehicle suspension system.
4. The system according to either of claims 2 or 3 wherein the control unit may comprise a predefined search pattern for movement of the wireless power transceiver of the vehicle with respect to the wireless power transceiver of the charging station so as to optimise the coupling efficiency therebetween.
5. The system of any of claim 2 to 4 wherein the control unit may be coupled to a measurement device for measuring the coupling efficiency between the wireless power transceiver of the vehicle and the wireless power transceiver of the charging station, and the control unit may comprise a storage device for storing the measured data and the relative position of the wireless power transceiver of the vehicle with respect to the wireless power transceiver of the charging station.
6. The system according to claim 4 wherein the control unit may be configured to move a vehicle and/or wireless power transceiver of the vehicle with respect to the wireless power transceiver of the charging station by searching for the maximum coupling efficiency between the wireless power transceiver of the vehicle and the wireless power transceiver of the charging station.
7. The system according to any preceding claim wherein the control unit comprises an image recognition system for automatically recognising a charging station.
8. The system according to any claim 7 wherein the control unit comprises a database of images of charging stations.
9. The system according to any claim 8 wherein the database is updateable by a vehicle operator.
10. The system according to any of claims 7 to 9 wherein the image recognition system recognises one or more optical targets or alignment aids which optical target or alignment aids facilitate calculation of a route to the charging station by the control unit.
11. A vehicle comprising the system of any of claims 1 to 10.
12. An electric vehicle having a traction battery for propulsion of the vehicle comprising the system for automatically aligning a vehicle with a charging station of any of claims 1 to 10.
13. A method for aligning a vehicle with a charging station, the method comprising: detecting or recognising a charging station via one or more sensors mounted to the vehicle; calculating a route between the vehicle's current position and that of the charging station so as to bring the vehicle into alignment with the charging station; and instructing one or more vehicle control systems to manoeuvre the vehicle such that vehicle is aligned with the charging station.
14. The method according to claim 13 wherein the vehicle is wirelessly coupled to the charging station and the sensors detect or recognise a wireless power transceiver of the charging station, the method comprising: calculating a route between the vehicle's current position and that of the charging station so as to bring a wireless power transceiver of the vehicle into alignment with the wireless power transceiver of the charging station; and instructing one or more vehicle control systems to manoeuvre the vehicle such that the wireless transceiver of the vehicle is aligned with the wireless transceiver of the charging station
15. The method according to claim 14 comprising measuring the coupling efficiency between the wireless transceiver of the vehicle and the wireless transceiver of the charging station.
16. The method according to claim 15 comprising storing the coupling efficiency and position of the wireless transceiver of the charging station with respect to the wireless transceiver of the vehicle in a memory device coupled to a control unit mounted to the vehicle.
17. The method according to any of claims 13 to 16 wherein instructing one or more vehicle control systems comprises instructing one or more vehicle systems to manoeuvre the vehicle and thereby the wireless transceiver of the vehicle with respect to the wireless transceiver of the charging station in a predefined search pattern.
18. The method according to any of claims 15 to 17 comprising storing the optimum position of the wireless transceiver of the vehicle with respect to the wireless transceiver of any given charging station visited by the vehicle in a memory device.
19. The method according claim 16 or 18 comprising recognising a charging station previously visited by the vehicle and recalling the optimum position of the wireless transceiver of the vehicle with respect to the wireless transceiver of the recognised charging station, and directing the vehicle so as to position the wireless transceiver in said optimum position. is20. The method according to any of claims 13 to 19 comparing an image or data received from the vehicle sensors with an image or data stored in a database of images of known charging stations.21. The method according to claims 20 comprising matching an image or data received from the vehicle sensors of an observed charging station with an image or data stored in a database of images of known charging stations and recalling alignment data of the observed charging station for calculation of a route to the observed charging station by the control unit.22. A system, vehicle or method substantially as described herein with reference to and/or as illustrated by the accompanying Figures.