Flux concentrator for an inductive power transfer system

• US 5,821,638 A
• Filed: 05/16/1996
• Issued: 10/13/1998
• Est. Priority Date: 10/21/1993
• Status: Expired due to Fees

• Current Assignee: Auckland UniServices Limited (Auckland University)
• Original Assignee: Auckland UniServices Limited (Auckland University)
• Inventors: Boys, John Talbot, Green, Andrew William
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Ganjian, Peter
• Application Number:
  US08/633,728
• Time in Patent Office: 880 Days
• Field of Search: 307/104, 307/17, 336/175, 336/184, 336/186, 336/187, 336/188, 336/200, 336/205, 336/206, 336/212, 336/233, 336/DIG. 3
• US Class Current: 307/104
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2200/44 Industrial trucks or floor conveyors
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2240/62 Vehicle position
• CPC Class Codes: B60L 2260/32 Auto pilot mode
• 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 53/22 Constructional details or arrangements of charging converters specially adapted for charging electric vehicles
• CPC Class Codes: B60L 53/32 by charging in short intervals along the itinerary, e.g. during short stops
• 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: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• 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 50/402 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 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: Y02P 90/60 Electric or hybrid propulsion means for production processes
• 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
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles

Abstract

A flux concentrator 1300 for an inductive power transfer system is made up from rectangular fingers 1301 of ferrite material held in close contact by compression means to form a large shock resistant core. The fingers are positioned at right angles to a primary conductor 1312 to concentrate the horizontal component of the magnetic flux through the flux concentrator. The fingers include bridge sections 1309 adapted to support pick-up coil windings 1307. The flux concentrator is covered by a conducting sheet of aluminum 1311 on the side of the magnetic core far away from the source of magnetic flux.

Claims

1. Inductive power pick-up means comprising at least one secondary conductor winding about a magnetizable core capable of collecting a magnetic flux from a nearby elongate primary conductor having a primary axis, wherein the magnetizable core has a length, which in use tends to be oriented at right angles to the primary axis of the primary conductor, a width, and a thickness;

at least part of the magnetizable core comprises two or more fingers of a ferrite material;

each said finger having at least one substantially flat side for making close contact with an adjacent said finger, the fingers being laid side by side across the length of the magnetizable core in an array wherein the flat sides of the fingers are held in close contact with one another by a compliant force exerting a compression force along the length of the magnetizable core, so that a permeability of the magnetizable core is substantially similar to that of a single mass of ferrite material of similar dimensions, yet because the fingers are capable of moving against one another, the array is capable of at least partially resembling a flexible magnetizable core capable of undergoing distortion without permanent loss of function.

2. Inductive power pick-up means as claimed in claim 1, wherein the core comprises more than one set of the fingers, each said set of fingers being spaced apart from an adjacent said set of fingers, and each said set of fingers being magnetically connected to an adjacent said set of fingers by means of a bridge of ferrite material.

3. Inductive power pick-up means as claimed in claim 2, wherein each said bridge comprises a slab of ferrite material.

4. Inductive power pick-up means as claimed in claim 3, wherein each said secondary conductor is wound around a respective said bridge.

5. Inductive power pick-up means as claimed in claim 4, wherein each said slab contacts at least one of the fingers from each said adjacent set of fingers.

6. Inductive power pick-up means as claimed in claim 4, wherein each said slab is connected to a pair of bars, one said bar being at each end of said slab, with each said bar contacting at least one of the fingers from a respective said set of fingers.

7. Inductive power pick-up means as claimed in claim 4, wherein each said set of fingers has at least four said fingers of ferrite material.

8. Inductive power pick-up means as claimed in claim 4, wherein each said finger is comprised of a ferrite material having a relative magnetic permeability of at least 1000.

9. Inductive power pick-up means as claimed in claim 1, wherein more than one pick-up coil is provided on a single said core.

10. Inductive power pick-up means as claimed in claim 9, wherein each said pick-up coil is tuned with an associated resonating capacitor and each said pick-up coil has its own rectifier to produce a DC output.

11. Inductive power pick-up means as claimed in claim 1, wherein a conducting sheet is positioned on a side of the magnetic core away from the primary conductor.

12. Inductive power pick-up means as claimed in claim 1, wherein each said finger is as thick as the thickness of the magnetizable core, and each finger is as long as the magnetic core is wide.