Pick-up apparatus for inductive power transfer systems

Abstract

An Inductive Power Transfer (IPT) pick-up apparatus includes a magnetically permeable core, a first coil, being wound about the core so as to be inductive coupled therewith such that a current induced in the first coil is most sensitive to a first directional component of magnetic flux and a second coil, being wound about the core so as to be inductively coupled therewith such that a current induced in the second coil is most sensitive to a second directional component of magnetic flux. The first directional component is substantially orthogonal to the second directional component.

What we claim is: 
     
       1. An Inductive Power Transfer (IPT) pick-up apparatus comprising:
 a magnetically permeable core;   a first coil, being wound about the core so as to be inductive coupled therewith such that a current induced in the first coil is most sensitive to a first directional component of magnetic flux; and   a second coil, being wound about the core so as to be inductively coupled therewith such that a current induced in the second coil is most sensitive to a second directional component of magnetic flux;   wherein the first directional component is substantially orthogonal to the second directional component.   
     
     
       2. An IPT pick-up apparatus as claimed in  claim 1 , wherein the first directional component is a vertical component of magnetic flux and the second directional component is a horizontal component of magnetic flux. 
     
     
       3. An IPT pick-up apparatus as claimed in  claim 1 , wherein the first and second coils are wound orthogonally to each other such that the current induced in one coil is most sensitive to the first directional component of magnetic flux, and the current induced in the other coil is most sensitive to the second directional component of magnetic flux. 
     
     
       4. An IPT pick-up apparatus as claimed in  claim 1 , wherein the first coil comprises a first pair of half-coils, and the second coil comprises a second pair of half-coils. 
     
     
       5. An IPT pick-up apparatus as claimed in  claim 1 , wherein the core is constructed with a flat E cross-section. 
     
     
       6. An IPT pick-up apparatus as claimed in  claim 1 , wherein the core is constructed from a permeable ferrous material such as ferrite. 
     
     
       7. An IPT pick-up apparatus as claimed in  claim 1 , wherein each coil is independently tuned with one or more capacitors. 
     
     
       8. An IPT pick-up apparatus as claimed in  claim 1 , wherein the apparatus comprises an electrical circuit to independently rectify the current induced in each coil. 
     
     
       9. An IPT pick-up apparatus as claimed in  claim 1 , wherein the apparatus comprises an electrical circuit to sum and regulate the rectified output from the coils such that the total output power is essentially constant over a wide range of lateral movement of the apparatus relative to the source of magnetic flux. 
     
     
       10. An Inductive Power Transfer (IPT) pick-up apparatus comprising:
 a magnetically permeable E-shaped core having at least three substantially parallel legs and connection regions connecting adjacent legs to each other, the connection regions having an axis which is orthogonal to the axes of the legs;   a first set of part-coils and a second set of part-coils each wound about the core so as to be inductively coupled therewith, the first set being arranged such that the current induced therein is most sensitive to a directional component of magnetic flux substantially parallel to the axes of the legs, and the second set being arranged to be sensitive to a directional component of magnetic flux substantially parallel to the axis of the connection portions.   
     
     
       11. An IPT pick-up apparatus as claimed in  claim 10 , wherein at least one of the part-coils of the first set and at least one of the part-coils of the second set is provided on one of the connection regions and at least one of the part-coils of each set is provided on one or more other connection regions. 
     
     
       12. An IPT pick-up apparatus as claimed in  claim 10 , wherein one or more separate tuning capacitors are provided for each coil set. 
     
     
       13. An Inductive Power Transfer (IPT) pick-up apparatus comprising:
 a magnetically permeable core;   a first coil, being wound about the core so as to be inductive coupled therewith such that a current induced in the first coil is most sensitive to a first directional component of magnetic flux;   a second coil, being wound about the core so as to be inductively coupled therewith such that a current induced in the second coil is most sensitive to a second directional component of magnetic flux; and   a track having one or more primary conductors, the one or more primary conductors being capable of providing the magnetic flux;   wherein the first directional component is substantially orthogonal to the second directional component.   
     
     
       14. An Inductive Power Transfer (IPT) pick-up apparatus comprising:
 a magnetically permeable E-shaped core having at least three substantially parallel legs and connection regions connecting adjacent legs to each other, the connection regions having an axis which is orthogonal to the axes of the legs;   a first set of part-coils and a second set of part-coils each wound about the core so as to be inductively coupled therewith, the first set being arranged such that the current induced therein is most sensitive to a directional component of magnetic flux substantially parallel to the axes of the legs, and the second set being arranged to be sensitive to a directional component of magnetic flux substantially parallel to the axis of the connection portions; and   a track having one or more primary conductors, the one or more primary conductors being capable of providing the magnetic flux.   
     
     
       15. An inductive power transfer apparatus comprising:
 a tuned multiple coil inductive power pick-up, the pick-up including a first tuned coil and a second tuned coil, wherein:
 a current induced in the first tuned coil being most sensitive to a first directional component of magnetic flux generated by a first track segment configured to generate a corresponding anticlockwise magnetic field in response to current flowing in a first direction through the first track; and 
 a current induced in the second tuned coil being most sensitive to a second directional component of magnetic flux generated by a second track segment configured to generate a corresponding clockwise magnetic field in response to current flowing in a second direction through the second track segment, the second direction opposite from the first direction; and 
   an electrical circuit configured to sum and regulate the currents induced in the first and second tuned coils to provide a substantially constant total power output over a range of lateral movement of the pick-up without requiring a battery, the range including at least a first pick-up position over the first track to a third pick-up position over a third track;   wherein:
 the third track segment is configured to generate a corresponding anticlockwise magnetic field in response to current flowing in the first direction through the third track; 
 the first, second, and third segments are arranged substantially in a common plane such that the generated magnetic field exits between the first and second track segments and enters between the second and third track segments; and 
 the generated magnetic field further includes the first and second directional components of magnetic flux. 
   
     
     
       16. The inductive power transfer apparatus of claim 15, further comprising a fourth track segment configured to generate a corresponding clockwise magnetic field in response to current flowing through the fourth track segment, the fourth track segment arranged substantially in a common plane with the first, second and third track segments such that the generated magnetic field further exits between the third and fourth track segments. 
     
     
       17. The inductive power transfer apparatus of claim 15, wherein the second track segment is arranged between the first track segment and the third track segment. 
     
     
       18. The apparatus of claim 15, wherein the first, second and third track segments are configured as a single phase track system. 
     
     
       19. The apparatus of claim 15, wherein the first, second and third track circuit are configured as a multi-phase track system. 
     
     
       20. The apparatus of claim 15, wherein the horizontal pick-up position range includes a lateral pick-up movement of at least 50 mm, the lateral pick-up movement being perpendicular to the first, second, and third track segments. 
     
     
       21. The apparatus of claim 15, wherein the first and second tuned coils are each independently connected to one or more tuned capacitors. 
     
     
       22. The apparatus of claim 15, further comprising an electrical circuit configured to independently rectify the current induced in each of the first and second tuned coils. 
     
     
       23. An inductive power transfer apparatus comprising:
 a first track segment configured to generate a corresponding anticlockwise magnetic field in response to current flowing in a first direction through the first track;   a second track segment configured to generate a corresponding clockwise magnetic field in response to current flowing in a second direction through the second track segment, the second direction opposite from the first direction;   a third track segment configured to generate a corresponding anticlockwise magnetic field in response to current flowing in the first direction through the third track, the first, second, and third segments arranged substantially in a common plane such that the generated magnetic field exits between the first and second track segments and enters between the second and third track segments, the generated magnetic field further including first and second directional components of magnetic flux; and   a tuned multiple coil inductive power pick-up, the pick-up including a first tuned coil and a second tuned coil, a current induced in the first tuned coil being most sensitive to the first directional component of magnetic flux, and a current induced in the second tuned coil being most sensitive to the second directional component of magnetic flux, and an electrical circuit configured to sum and regulate the currents induced in the first and second tuned coils to provide a substantially constant total power output over a range of lateral movement of the pick-up without requiring a battery, the range including at least a first pick-up position over the first track to a third pick-up position over the third track.