Magnetic probe-based current measurement device, and measurement method
A magnetic probe-based current measurement device and measurement method is disclosed. The device comprises a conductor for a current under test, a magnetic probe, a magnetic bias structure, and a programmable chip. A conductor has a first axis, a second axis, and a third axis. The conductor is provided with through holes. The direction of the through holes are parallel to the third axis. Vertical projections of the through holes on a first cross section are symmetric about the first axis. At least one of the through holes has a center position located on the first axis. And/or every pair of the through holes have center positions that are symmetric about the first axis. The magnetic probe is provided within the through holes, and is electrically connected to the programmable chip. A sensitive center position of the magnetic probe is located on the first cross section. A vertical projection of the magnetic probe on the first cross section is symmetric about the first axis. The magnetic bias structure is provided within the through holes. A magnetization direction of the magnetic bias structure is perpendicular to a sensitive direction of the magnetic probe. The device is small size and has the advantages of high measurement accuracy, and high adaptability.
1. A magnetic probe-based current measurement device, comprising:
a conductor for a current under test,
a magnetic probe,
a magnetic bias structure, and
a programmable chip;
wherein
the conductor for a current under test has a first axis, a second axis, and a third axis, the first axis is parallel to a current direction of the conductor for a current under test, the second axis and the first axis are perpendicular to each other and form a first cross section, and the third axis is perpendicular to the first cross section;
the conductor for a current under test is provided with one or more through holes, the direction of the one or more through holes is parallel to the third axis, and vertical projections of the one or more through holes on the first cross section are symmetrical about the first axis;
the magnetic probe includes devices to form a differential magnetic probe within each of the one or more through holes, and is electrically connected to the programmable chip, and a sensitive center position for each of the devices of the magnetic probe is located on the first cross section;
the magnetic bias structure is provided within the one or more through holes, and a magnetization direction of the magnetic bias structure is perpendicular to a sensitive direction of the magnetic probe, and both the magnetic probe and the magnetic bias structure are symmetrical about the first axis; and
the magnetic probe is used to acquire a magnetic field signal generated by the current under test introduced into the conductor for a current under test, convert the magnetic field signal into a voltage signal, and transmit the voltage signal to the programmable chip; and the programmable chip is used to process the voltage signal to obtain a target voltage signal, and the target voltage signal corresponds to the current under test.
2. The current measurement device according to claim 1 , wherein the vertical projections of the one or more through holes on the first cross section are symmetrical about the second axis.
3. The current measurement device according to claim 2 , wherein in a direction where the first axis is located, a length L 1 of the conductor for a current under test and a length L 2 of the one or more through holes meet L 1 ≥3L 2 .
4. The current measurement device according to claim 1 , further comprising a circuit board,
wherein the magnetic probe comprises M groups of magnetoresistive sensors, each group of the magnetoresistive sensors comprises N pairs of magnetoresistive elements, the magnetoresistive elements are arranged on the circuit board, vertical projections of each pair of the magnetoresistive elements on the first cross section are symmetrical about the first axis, sensitive directions of each pair of the magnetoresistive elements are parallel and opposite to each other, M and N are positive integers, and M≥1, N≥1.
5. The current measurement device according to claim 4 , wherein the magnetic bias structure and the magnetoresistive elements are arranged on a same side of the circuit board.
6. The current measurement device according to claim 4 , wherein the magnetic bias structure and the magnetoresistive elements are respectively located on two opposite sides of the circuit board.
7. The current measurement device according to claim 1 , wherein the vertical projections of the through holes on the first cross section have a shape comprising any one of rectangle, circle, and ellipse.
8. The current measurement device according to claim 1 , wherein the conductor for a current under test is metal, and a cross-section shape of a cross section perpendicular to the first axis comprises any one of rectangle and circle.
9. The current measurement device according to claim 1 , wherein the magnetic bias structure is a permanent magnet, and the permanent magnet is made of any one of neodymium iron boron, samarium cobalt, aluminum nickel cobalt and ferrite.
10. The current measurement device according to claim 1 , wherein the programmable chip comprises:
a temperature compensation unit,
a nonlinear compensation unit, and
an operational amplifier;
wherein
the temperature compensation unit is electrically connected to the magnetic probe, and the nonlinear compensation unit is electrically connected between the temperature compensation unit and the operational amplifier;
the temperature compensation unit is used to perform temperature compensation on a voltage signal output by the magnetic probe to obtain a primary voltage signal;
the nonlinear compensation unit is used to perform nonlinear compensation on the primary voltage signal to obtain a secondary voltage signal; and
the operational amplifier is used to linearly amplify the secondary voltage signal to obtain the target voltage signal.
11. A magnetic probe-based current measurement method, performed by using the current measurement device according to claim 1 , and comprising:
accessing a current under test into the conductor for a current under test,
acquiring a magnetic field signal generated by the current under test through the magnetic probe, converting the magnetic field signal into a voltage signal, and transmitting the voltage signal to the programmable chip, and
processing the voltage signal by the programmable chip to obtain a target voltage signal, wherein the target voltage signal corresponds to the current under test.
12. The current measurement device according to claim 1 , wherein at least one of the one or more through holes has a center position location on the first axis.
13. The current measurement device according to claim 1 , wherein the one or more through holes include at least one pair of through holes, each of the at least one pair of through holes has a center position that is symmetrical about the first axis.