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. A pick-up apparatus comprising:
 a magnetically permeable core arranged to capture magnetic flux from a source of magnetic flux having vertical and horizontal directional components;   a first tuned coil being inductively coupled to the magnetically permeable core such that a current induced in the first tuned coil is most sensitive to the vertical directional component of magnetic flux;   a second tuned coil being inductively coupled to the magnetically permeable core such that a current induced in the second tuned coil is most sensitive to the horizontal directional component of magnetic flux; and   an electrical circuit configured to sum and regulate a rectified electrical output from the first and second tuned coils to provide a total power output that is substantially constant over a wide range of lateral movement of the apparatus relative to a source of magnetic flux,   wherein at least one of the first tuned coil or the second tuned coil overlaps the other of the first tuned coil or the second tuned coil, and a geometric center of the first tuned coil is substantially offset from a geometric center of the second tuned coil.   
     
     
       16. The pick-up apparatus of claim 15, wherein the first and second tuned coils are each independently connected to one or more tuned capacitors. 
     
     
       17. The pick-up apparatus of claim 15, wherein the electrical circuit is configured to independently rectify the current induced in each of the first and second tuned coils. 
     
     
       18. The pick-up apparatus as claimed in claim 15, wherein the first and second tuned coils are connected in parallel to one or more tuning capacitors. 
     
     
       19. The pick-up apparatus as claimed in claim 15, wherein the electrical circuit provides a total power output that is substantially constant over a wide range of lateral movement of the apparatus without requiring a battery. 
     
     
       20. The pick-up apparatus as claimed in claim 15, wherein the pick-up apparatus is configured to match an effective short circuit current between each of the tuned coils, and to match an effective open circuit voltage between each of the tuned coils. 
     
     
       21. The pick-up apparatus of claim 15, wherein the core is established by three substantially parallel vertical legs and orthogonal connection regions connecting adjacent legs to each other. 
     
     
       22. The pick-up apparatus of claim 15, wherein the first tuned coil and the second tuned coil are wound about a leg of the core that extends in a direction that is parallel to the vertical directional component, the core having portions extending normal to the vertical direction component on two opposite sides of the leg. 
     
     
       23. The pick-up apparatus of claim 15, wherein the magnetically permeable core has a height that is less than half the width, wherein the height is measured in a direction parallel to a vector from the source of the magnetic flux to the core when the core is over the source, and the width is normal to the height. 
     
     
       24. A pick-up apparatus comprising:
 a magnetically permeable core arranged to capture magnetic flux from a source of magnetic flux having vertical and horizontal directional components;   a first tuned coil being inductively coupled to the magnetically permeable core such that a current induced in the first tuned coil is most sensitive to the vertical directional component of magnetic flux;   a second tuned coil being inductively coupled to the magnetically permeable core such that a current induced in the second tuned coil is most sensitive to the horizontal directional component of magnetic flux; and   an electrical circuit configured to sum and regulate a rectified electrical output from the first and second tuned coils to provide a total power output that is substantially constant over a wide range of lateral movement of the apparatus relative to a source of magnetic flux,   wherein an axis of winding of the first tuned coil is at least generally parallel with an axis of winding of the second tuned coil.   
     
     
       25. The pick-up apparatus of claim 24, wherein the core is constructed with an E cross-section. 
     
     
       26. The pick-up apparatus of claim 24, wherein the first and second tuned coils are each independently connected to one or more tuned capacitors. 
     
     
       27. The pick-up apparatus of claim 24, wherein the electrical circuit is configured to independently rectify the current induced in each of the first and second tuned coils. 
     
     
       28. The pick-up apparatus as claimed in claim 24, wherein the first and second tuned coils are connected in parallel to one or more tuning capacitors. 
     
     
       29. The pick-up apparatus as claimed in claim 24, wherein the electrical circuit provides a total power output that is substantially constant over a wide range of lateral movement of the apparatus without requiring a battery. 
     
     
       30. The pick-up apparatus as claimed in claim 24, wherein the pick-up apparatus is configured to match an effective short circuit current between each of the tuned coils, and to match an effective open circuit voltage between each of the tuned coils. 
     
     
       31. The pick-up apparatus of claim 24, wherein the core is established by three substantially parallel vertical legs and orthogonal connection regions connecting adjacent legs to each other. 
     
     
       32. The pick-up apparatus of claim 24, wherein the magnetically permeable core has a height that is less than half the width, wherein the height is measured in a direction parallel to a vector from the source of the magnetic flux to the core when the core is over the source, and the width is normal to the height. 
     
     
       33. A pick-up apparatus comprising:
 a magnetically permeable core arranged to capture magnetic flux from a source of magnetic flux having vertical and horizontal directional components;   a first tuned coil being inductively coupled to the magnetically permeable core such that a current induced in the first tuned coil is most sensitive to the vertical directional component of magnetic flux;   a second tuned coil being inductively coupled to the magnetically permeable core such that a current induced in the second tuned coil is most sensitive to the horizontal directional component of magnetic flux; and   an electrical circuit configured to sum and regulate a rectified electrical output from the first and second tuned coils to provide a total power output that is substantially constant over a wide range of lateral movement of the apparatus relative to a source of magnetic flux,   wherein the core is established by three substantially parallel vertical legs and orthogonal connection regions connecting adjacent legs to each other.   
     
     
       34. The pick-up apparatus of claim 33, wherein the first and second tuned coils are each independently connected to one or more tuned capacitors. 
     
     
       35. The pick-up apparatus of claim 33, wherein the electrical circuit is configured to independently rectify the current induced in each of the first and second tuned coils. 
     
     
       36. The pick-up apparatus as claimed in claim 33, wherein the first and second tuned coils are connected in parallel to one or more tuning capacitors. 
     
     
       37. The pick-up apparatus as claimed in claim 33, wherein the electrical circuit provides a total power output that is substantially constant over a wide range of lateral movement of the apparatus without requiring a battery. 
     
     
       38. The pick-up apparatus as claimed in claim 33, wherein the pick-up apparatus is configured to match an effective short circuit current between each of the tuned coils, and to match an effective open circuit voltage between each of the tuned coils. 
     
     
       39. The pick-up apparatus of claim 33, wherein an axis of winding of the first tuned coil is at least generally parallel with an axis of winding of the second tuned coil. 
     
     
       40. The pick-up apparatus of claim 33, wherein the first tuned coil and the second tuned coil are wound about a leg of the core that extends in a direction that is parallel to the vertical directional component, the core having portions extending normal to the vertical direction component on two opposite sides of the leg. 
     
     
       41. The pick-up apparatus of claim 33, wherein the magnetically permeable core has a height that is less than half the width, wherein the height is measured in a direction parallel to a vector from the source of the magnetic flux to the core when the core is over the source, and the width is normal to the height.