Device for measuring a component of current based on magnetic fields
A magnetic-field-measuring probe includes at least two magnetoresistive sensors which are sensitive to respective magnetic fields along a determined measurement axis. The at least two magnetoresistive sensors are rigidly connected to one another in a position such that the measurement axes thereof are at an angle other than zero. Output terminals specific to each magnetoresistive sensor are used to supply a signal that is representative of the field measured by each sensor along the measurement axis thereof. The difference between the derivative of a first magnetic field relative to a second direction and the derivative of a second magnetic field relative to a first direction is calculated to determine a component of current to be measured.
1. Device for measuring at least one component of a current comprising:
at least one probe comprising a first and a second mangetoresistive or magnetoinductive sensors which are adapted to detect a first and respectively a second magnetic fields along a first and respectively a second predetermined selected measurement axes, the first and the second predetermined selected measurement axes having a first and respectively a second directions, the first and second sensors being rigidly connected to each other in a position such that the first and second measurement axes are at an angle other than zero, the probe further comprising output terminals which are specific to each sensor in order to provide a signal which is representative of the magnetic field measured by each of the sensors along the selected measurement axis thereof;
a computing device for determining a derivative of the first magnetic field relative to the second direction and a derivative of the second magnetic field relative to the first direction, the computing device calculating a difference between the derivative of the first magnetic field relative to the second direction and the derivative of the second magnetic field relative to the first direction, said difference being representative of a component of the current.
2. Device according to claim 1 , wherein all the sensors of the probe are distributed on a same layer.
3. Device according to claim 1 , further comprising:
a specific processing chain connected to each magnetoresistive sensor, each processing chain processing the signal from the magnetoresistive sensor; and
means for processing the signals from each said processing chain.
4. Device according to claim 1 , further comprising a mechanism for displacing the probe along the second direction from a first position to a second position, the probe measuring the first magnetic field at the first and second positions, the computing device determining:
a distance between the first and second positions,
a difference between the first magnetic field at said first position and the first magnetic field at the second position,
a ratio between said difference and said distance, said ratio being the derivative of the first magnetic field relative to the second direction.
5. Device according to claim 4 , wherein the mechanism displaces the probe along the first direction between two positions, the probe measuring the second magnetic field at the two positions, the computing device determining:
a distance between the two positions,
a difference between the second magnetic field at one of said two positions and the second magnetic field at another of said two positions,
a ratio between said difference and said distance, said ratio being the derivative of the second magnetic field relative to the first direction.
6. Device according to claim 1 , wherein the probe comprises a third and a fourth magnetoresistive or magnetoinductive sensors which are adapted to detect a third and respectively a fourth magnetic fields along a third and respectively a fourth predetermined selected measurement axes, the third and the fourth predetermined selected measurement axes being parallel to the first and respectively the second directions; the computing device calculating:
a difference between the first and the second magnetic fields,
a distance between the first and the third sensors,
a ratio between said difference and the distance between said first and third sensors, said ratio being the derivative of the first magnetic field relative to the second direction,
a difference between the second and the fourth magnetic fields,
a distance between the second and the fourth sensors,
a ratio between said difference and the distance between said second and fourth sensors, said ratio being the derivative of the second magnetic field relative to the first direction.
7. Device according to claim 6 , wherein the first and the second sensors are arranged on a first integrated circuit, the third and the fourth sensors are arranged on a second integrated circuit, the second integrated circuit being arranged parallel with the first integrated circuit.
8. Device according to claim 1 , wherein the probe comprises a first semiconductor substrate, the first and the second sensors being formed in said first semiconductor substrate, the first and the second sensors having selected detection axes which are arranged perpendicularly relative to each other.
9. Device according to claim 8 , wherein the sensors of the same layer have their selected measurement axes parallel.
10. Device according to claim 1 , comprising two superimposed layers made of superconductive material, one of said superimposed layers comprising one part of the sensors, another of said superimposed layers comprising another part of the sensors.
11. Device according to claim 10 , wherein the selected measurement axes of the sensors of different layers are at an angle other than zero.
12. Device according to claim 10 , wherein the sensors of the same layer have their selected measurement axes parallel.