Flexible current sensor arrangement

1. A flexible current sensor arrangement comprising a plurality of discrete current sensing elements distributed along an elongate flexible carrier, the elongate flexible carrier comprising a plurality of spools linked to one another by linking portions, each of the spools being configured to receive at least one current sensing element, the linking portions being configured to allow rotation of adjacent spools about an axis of rotation, the linking portions being aligned with the longitudinal axis of the elongate flexible carrier or being offset from the longitudinal axis such that, as adjacent spools rotate about the linking portions, a centre-to-centre separation of the adjacent spools is maintained at closer to a constant value on average than when the linking portions are aligned with the longitudinal axis.

2. The flexible current sensor arrangement of claim 1 , wherein a cross-section of each sensing element, through which the flexible carrier passes, is longer in a first dimension than in a second dimension, the first dimension being parallel to the axis of rotation.

3. The flexible current sensor arrangement of claim 1 , the flexible current sensor arrangement being configurable into an openable loop.

4. The flexible current sensor arrangement of claim 1 , wherein the elongate flexible carrier is configured such that it has a preferred axis of flexure.

5. The flexible current sensor arrangement of claim 4 , wherein the elongate flexible carrier is configured such that is has a single axis of flexure.

6. The flexible current sensor arrangement of claim 4 , wherein the flexibility of the elongate flexible carrier about the preferred axis of flexure is asymmetric.

7. The flexible current sensor arrangement of claim 3 , wherein when the arrangement is configured in a loop, opposing ends of the flexible carrier lie in the same plane as the remainder of the carrier.

8. The flexible current sensor arrangement of claim 1 , wherein the discrete sensing elements are substantially equidistantly spaced along the elongate flexible carrier.

9. The flexible current sensor arrangement of claim 1 , comprising:

a first connector element at a first end of the elongate flexible carrier;

a second connector element at a second end of the elongate flexible carrier, the first and second connector elements being configured to engage releasably with one another to form the sensor arrangement into a closed loop, wherein the discrete sensing elements are equidistantly spaced around the closed loop.

10. The flexible current sensor arrangement of claim 9 , wherein the first and second connector elements are configured such that, when they are connected to one another thereby configuring the arrangement into a closed loop, the distance between the sensing elements at each end of the carrier is substantially the same as the distance between each of the other sensing elements on the carrier and its immediate neighbours.

11. The flexible current sensor arrangement of claim 1 , the elongate flexible carrier passing through a central region of each of the current sensing elements.

12. The flexible current sensor arrangement of claim 1 , each current sensing element having a plane of zero sensitivity to uniform magnetic fields, the flexible current sensor arrangement being configured such that the plane of zero sensitivity of each sensing element is substantially locally perpendicular to the longitudinal axis of a portion of the elongate flexible carrier on which it is carried.

13. The flexible current sensor arrangement of claim 1 , wherein the discrete sensing elements comprise a plurality of turns of copper wire wound around one of the spools.

14. The flexible current sensor arrangement of claim 1 , wherein the plurality of linked carrier portions are detachably linked to one another by the linking portions.

15. The flexible current sensor arrangement of claim 1 , wherein the linking portions are permanently coupled to the spools such that adjacent spools cannot be detached from one another.

16. The flexible current sensor arrangement of claim 1 wherein the linking portions are configured so as to minimise a change in separation of centres of adjacent spools as the spools rotate about the linking portions.

17. The flexible current sensor arrangement of claim 1 , wherein the linking portions are offset from the longitudinal axis towards a preferred direction of flexure of the flexible elongate carrier.

18. The flexible current sensor arrangement of claim 1 , wherein the discrete current sensing elements comprise circuit board coils centrally mounted on the elongate flexible carrier.

19. An elongate flexible member for a current sensor arrangement, the elongate flexible member comprising a plurality of spools linked to one another by linking portions, each spool being configured for receiving a discrete current sensing element, the linking portions allowing rotation of adjacent spools about an axis of rotation, the linking portions being aligned with the longitudinal axis of the elongate flexible carrier or being offset from the longitudinal axis such that, as adjacent spools rotate about the linking portions, a centre-to-centre separation of the adjacent spools is maintained at closer to a constant value on average than when the linking portions are aligned with the longitudinal axis.

20. A method of manufacturing a flexible current sensor arrangement, the method comprising:

providing an elongate flexible carrier, the elongate flexible carrier comprising a plurality of spools linked to one another by linking portions, each of the spools being configured to receive at least one current sensing element, the linking portions allowing rotation of adjacent spools about an axis of rotation, the linking portions being aligned with the longitudinal axis of the elongate flexible carrier or being offset from the longitudinal axis such that, as adjacent spools rotate about the linking portions, a centre-to-centre separation of the adjacent spools is maintained at closer to a constant value on average than when the linking portions are aligned with the longitudinal axis; and

distributing a plurality of discrete sensing elements along the elongate flexible carrier.