Current sensor having conductor between pair of plate-like magnetic shields
Each of three magnetic sensors is positioned on a first virtual line that passes the centers of two magnetic shields in the width direction and is perpendicular to a virtual plane, so a value detected by the magnetic sensor is less likely to be influenced by an external magnetic field. The first virtual line and the center of a conductor intersecting the first virtual line are separated from each other by a certain distance. Therefore, even if a distance from the center of the conductor in the width direction to the magnetic sensor is short, it is possible to improve, on a high-frequency side, frequency characteristics in the detection sensitivity of the magnetic sensor for the frequency of the current under measurement.
1. A current sensor comprising:
a plurality of plate-like conductors, each having a plate surface positioned in a same virtual plane, the plurality of conductors extending in a first direction and being aligned in parallel to one another; and
a plurality of current detectors, each of which detects a current flowing through corresponding one of the plurality of conductors, each of the current detectors including:
a pair of plate-like magnetic shields, each having a plate surface parallel to the virtual plane, the pair of magnetic shields facing each other with the corresponding conductor interposed therebetween, the pair of magnetic shields having a same length in a second direction perpendicular to the first direction, a first virtual line being defined for the pair of magnetic shields, the first virtual line being perpendicular to the virtual plane and passing through a center of each of the pair of magnetic shields with respect to the second direction; and
a magnetic sensor provided between the pair of magnetic shields and positioned on the first virtual line,
wherein each conductor has a first conductor portion positioned between the pair of magnetic shields such that the first virtual line intersects the first conductor portion, the first conductor portion having such a width in the second direction that a center of the first conductor portion in the second direction is shifted from the first virtual line in the second direction.
2. The current sensor according to claim 1 , wherein when the first conductor portion has the width W in the second direction,
the pair of magnetic shield has the length L in the second direction which is at least 2×W and no greater than 5×W, and
the first virtual line and the center of the first conductor portion are separated from each other in the second direction by a distance D greater than (W/2)×(16/32) and smaller than (W/2)×(20/32).
3. The current sensor according to claim 1 , wherein when the first conductor portion has the width W in the second direction,
the pair of magnetic shield has the length L in the second direction which is at least 2×W and no greater than 5×W, and
the first virtual line and the center of the first conductor portion are separated from each other in the second direction by a distance D greater than (W/2)×(17/32) and smaller than (W/2)×(19/32).
4. The current sensor according to claim 1 , further comprising a circuit board on which the plurality of magnetic sensors of the plurality of current detectors are mounted,
wherein the plurality of magnetic sensors are positioned along a second virtual line parallel to the virtual plane and extending in the second direction.
5. The current sensor according to claim 4 , wherein each conductor has second conductor portions extending in the first direction from both ends of the first conductor portion in the first direction, the second conductor portions having a width in the second direction greater than the width of the first conductor portion.
6. The current sensor according to claim 5 , wherein:
the plurality of conductors include three or more equally spaced conductors such that a middle conductor is disposed between two conductors, the middle conductor having a third virtual line extending in the first direction and passing a center of the width of the second conductor portions, the third virtual line intersecting the first virtual line defined for the pair of the magnetic shields in the corresponding current detector provided for the middle conductor.
7. The current sensor according to claim 6 , wherein the first conductor portion and the second conductor portions extending therefrom share a common side edge linearly extending in the first direction.
8. The current sensor according to claim 5 , wherein the first conductor portion is entirely positioned between the pair of magnetic shields.