A current sensor system

Abstract

The present invention provides a current sensor system, which includes: a first current sensor including a first current-carrying conductor and a first magnetic sensor located around the first current-carrying conductor; a second current sensor including a second current-carrying conductor and a second magnetic sensor located around the second current-carrying conductor; wherein one end of the first current-carrying conductor is electrically connected to one end of the second current-carrying conductor, and the measured current flows through the first current-carrying conductor and the second current-carrying conductor in sequence. Compared with the prior art, in the current sensor system of the present invention, an external magnetic field in the non-sensitive axis direction causes the output or sensitivity of the first current sensor to increase or decrease, and an external magnetic field in the non-sensitive axis direction causes the output or sensitivity of the second current sensor to decrease or increase, so that the external magnetic field suppression can be improved, and further the detection accuracy of the current can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of current sensors, and in particular to a current sensor system that uses dual current sensors to enhance external magnetic field suppression.

Background Art

[0002] Current sensors for measuring the magnitude of current are widely used in various electronic devices. For current sensors, the presence of an external magnetic field in the non-sensitive axis direction will change the sensitivity of the magnetoresistive sensor in the current sensor, thereby reducing the detection accuracy of the current.

[0003] Therefore, it is necessary to propose a technical solution to overcome the above problems.

Summary of the Invention

[0004] One of the objectives of the present invention is to provide a current sensor system that can enhance external magnetic field suppression, thereby improving the detection accuracy of the current.

[0005] According to one aspect of the present invention, there is provided a current sensor system, which includes: a first current sensor including a first current-carrying conductor and a first magnetic sensor, the first magnetic sensor being located around the first current-carrying conductor; a second current sensor including a second current-carrying conductor and a second magnetic sensor, the second magnetic sensor being located around the second current-carrying conductor; wherein one end of the first current-carrying conductor is electrically connected to one end of the second current-carrying conductor, and the measured current flows through the first current-carrying conductor and the second current-carrying conductor in sequence.

[0006] Further, an external magnetic field in the non-sensitive axis direction causes the output of the first current sensor to increase or decrease, and an external magnetic field in the non-sensitive axis direction causes the output of the second current sensor to decrease or increase.

[0007] Further, the direction of the magnetoresistive moment in the second current sensor is opposite to the direction of the magnetoresistive moment in the first current sensor.

[0008] Further, the first current sensor and the second current sensor are centrosymmetric.

[0009] Further, the first current-carrying conductor includes a first leg, a second leg, and a first connecting portion. The first leg and the second leg are located on the same side of the first connecting portion. One end of the first leg serves as the other end of the first current-carrying conductor, and the other end of the first leg is connected to one end of the first connecting portion. One end of the second leg serves as one end of the first current-carrying conductor, and the other end of the second leg is connected to the other end of the first connecting portion. The second current-carrying conductor includes a third leg, a fourth leg, and a second connecting portion. The third leg and the fourth leg are located on the same side of the second connecting portion. One end of the third leg serves as one end of the second current-carrying conductor, and the other end of the third leg is connected to one end of the second connecting portion. One end of the fourth leg serves as the other end of the second current-carrying conductor, and the other end of the fourth leg is connected to the other end of the second connecting portion.

[0010] Further, the first magnetic sensor includes a first magnetic sensor unit and a second magnetic sensor unit. The first sensor unit and the second magnetic sensor unit are located around the first current-carrying conductor to form a differential output. The second magnetic sensor includes a third magnetic sensor unit and a fourth magnetic sensor unit. The third magnetic sensor unit and the fourth magnetic sensor unit are located around the second current-carrying conductor to form a differential output.

[0011] Further, both the first magnetic sensor and the second magnetic sensor are magnetoresistive sensors. The first magnetic sensor unit and the second magnetic sensor unit are respectively located above the first leg and the second leg. The third magnetic sensor unit and the fourth magnetic sensor unit are respectively located above the third leg and the fourth leg. Or the first magnetic sensor unit and the second magnetic sensor unit are respectively located below the first leg and the second leg. The third magnetic sensor unit and the fourth magnetic sensor unit are respectively located below the third leg and the fourth leg.

[0012] Further, the average value of the outputs of the first current sensor and the second current sensor is used as the output of the current sensor system.

[0013] Further, the current sensor system further includes a current connection conductor. One end of the first current-carrying conductor is electrically connected to one end of the second current-carrying conductor via the current connection conductor.

[0014] Further, the current sensor system further includes a current input conductor and a current output conductor. The current input conductor is electrically connected to the other end of the first current-carrying conductor. The current output conductor is electrically connected to the other end of the second current-carrying conductor.

[0015] Compared with the prior art, the current sensor system in the present invention includes a first current sensor and a second current sensor. Among them, an external magnetic field in the non-sensitive axis direction increases or decreases the output or sensitivity of the first current sensor, and the external magnetic field in the non-sensitive axis direction decreases or increases the output or sensitivity of the second current sensor, so that the average value of the output or sensitivity of the first current sensor and the second current sensor is hardly affected by the external magnetic field, thereby enhancing the external magnetic field suppression and further improving the detection accuracy of the current.

Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0017] Figure 1 It is a schematic structural diagram of the current sensor system in an embodiment of the present invention;

[0018] Figure 2 For the effective anisotropy field H k = 200 G, the normalized sensitivity of the single current sensor and the current sensor system shown in the present invention Figure 1 The curve of the relationship between the normalized sensitivity and the magnetic field in the non-sensitive axis x direction.

Detailed Embodiments

[0019] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0020] As used herein, the term "one embodiment" or "embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. Unless otherwise specified, the words indicating electrical connection such as "connected", "coupled", and "joined" herein all mean direct or indirect electrical connection.

[0021] Please refer to Figure 1 As shown, it is a schematic structural diagram 100 of the current sensor system in an embodiment of the present invention. Figure 1 The current sensor system 100 shown includes a first current sensor 1, a second current sensor 2, a current input conductor 3, a current output conductor 4, and a current connection conductor 5.

[0022] The first current sensor 1 includes a first current-carrying conductor 102 and a first magnetic sensor 101. The first current-carrying conductor 102 is configured to provide a current path for the current I to be measured, and the first magnetic sensor 101 is disposed around the first current-carrying conductor 102.

[0023] The second current sensor 2 includes a second current-carrying conductor 202 and a second magnetic sensor 201. The second current-carrying conductor 202 is configured to provide a current path for the current I to be measured, and the second magnetic sensor 201 is disposed around the second current-carrying conductor 202.

[0024] One end of the first current-carrying conductor 102 is opposite to and electrically connected to one end of the second current-carrying conductor 202 through the current connection conductor 5, and the other end of the first current-carrying conductor 102 is opposite to and spaced apart from the other end of the second current-carrying conductor 202; the current input conductor 3 and the current output conductor 4 are opposite to and spaced apart from each other. The current input conductor 3 is electrically connected to the other end of the first current-carrying conductor 102, and the current output conductor 4 is electrically connected to the other end of the second current-carrying conductor 202. The current I to be measured flows in from the current input conductor 3, sequentially passes through the first current-carrying conductor 102, the current connection conductor 5, and the second current-carrying conductor 202, and flows out from the current output conductor 4.

[0025] In Figure 1 the specific embodiment shown, the current input conductor 3 and the current output conductor 4 are located outside the first current-carrying conductor 102 and the second current-carrying conductor 202, and the longitudinal extension directions of the current input conductor 3 and the current output conductor 4 are perpendicular to the longitudinal extension directions of the first current-carrying conductor 102 and the second current-carrying conductor 202.

[0026] In Figure 1 the embodiment shown, the structures of the first current sensor 1 and the second current sensor 2 are completely the same.

[0027] In the first current sensor 1, the first current-carrying conductor 102 is a U-shaped conductor, which includes a first leg 102a, a second leg 102b, and a first connecting portion 102c located between the first leg 102a and the second leg 102b. The first leg 102a and the second leg 102b are on the same side of the first connecting portion 102c. One end of the first leg 102a serves as the other end of the first current-carrying conductor 102, and the other end of the first leg 102a is connected to one end of the first connecting portion 102c; one end of the second leg 102b serves as one end of the first current-carrying conductor 102, and the other end of the second leg 102b is connected to the other end of the first connecting portion 102c. The first magnetic sensor 101 is a magnetoresistive sensor, which includes a first magnetoresistive sensor unit 101a and a second magnetoresistive sensor unit 101b. The first magnetoresistive sensor unit 101a and the second magnetoresistive sensor unit 101b are respectively located above the first leg 102a and the second leg 102b to form a differential output.

[0028] In the second current sensor 2, the second current-carrying conductor 202 is a U-shaped conductor, which includes a third leg 202a, a fourth leg 202b, and a second connecting portion 202c located between the third leg 202a and the fourth leg 202b. The third leg 202a and the fourth leg 202b are on the same side of the second connecting portion 202c. One end of the third leg 202a serves as one end of the second current-carrying conductor 202, and the other end of the third leg 202a is connected to one end of the second connecting portion 202c; one end of the fourth leg 202b serves as the other end of the second current-carrying conductor 202, and the other end of the fourth leg 202b is connected to the other end of the second connecting portion 202c. The second magnetic sensor 201 is a magnetoresistive sensor, which includes a third magnetoresistive sensor unit 201a and a fourth magnetoresistive sensor unit 201b. The third magnetoresistive sensor unit 201a and the fourth magnetoresistive sensor unit 201b are respectively located above the third leg 202a and the fourth leg 202b to form a differential output.

[0029] It should be specifically noted that in another embodiment, the first magnetoresistive sensor unit 101a and the second magnetoresistive sensor unit 101b can be respectively located below the first leg 102a and the second leg 102b to form a differential output; the third magnetoresistive sensor unit 201a and the fourth magnetoresistive sensor unit 201b are respectively located below the third leg 202a and the fourth leg 202b to form a differential output.

[0030] In Figure 1 the illustrated embodiment, the first current sensor 1 and the second current sensor 2 are centrosymmetric.

[0031] The definition of central symmetry is as follows: If a figure can coincide with another figure after being rotated 180 degrees around a certain point, these two figures are centrosymmetric. Therefore, the statement that the first current sensor 1 and the second current sensor 2 are centrosymmetric can also be expressed as: After the second current sensor 2 is rotated 180 degrees around a certain point, it can coincide with the first current sensor 1. Specifically, "the first current sensor 1 and the second current sensor 2 are centrosymmetric" includes: the first current-carrying conductor 102 and the second current-carrying conductor 202 are centrosymmetric; the first magnetic sensor 101 and the second magnetic sensor 201 are centrosymmetric.

[0032] After the second current sensor 2 is rotated 180 degrees around a certain point, it can coincide with the first current sensor 1, so that the direction of the magnetoresistance magnetic moment M in the second current sensor 2 is opposite to the direction of the magnetoresistance magnetic moment M in the first current sensor 1.

[0033] For the convenience of description, an xy coordinate system is defined in Figure 1 . Among them, the axis parallel to the direction of the magnetic moment M (non-sensitive axis) is defined as the x-axis, and the axis perpendicular to the direction of the magnetic moment M (sensitive axis) is defined as the y-axis. The external magnetic field is H y in the sensitive axis direction and H x in the non-sensitive axis direction.

[0034] The measured current I generates a magnetic field H 11 at the first magnetoresistive sensor unit 101a and a magnetic field -H 12 at the second magnetoresistive sensor unit 101b; the output of the first magnetoresistive sensor unit 101a is V 11 = [MR / (H k+ H x )][(H 11 / I)I + H y , where MR is the magnetoresistance ratio and H k is the effective anisotropy field; the output of the second magnetoresistive sensor unit 101b is V 12 = [MR / (H k + H x )][-(H 12 / I)I + H y ; the output of the first current sensor 1 is V1 = V 11 - V 12 = [MR / (H k + H x )][(H 11 + H 12 ) / I]I = [MR / (H k + H x)]GI, where G is the coupling constant from current to magnetic field. From the output formula of the first current sensor 1, it can be seen that the external magnetic field H in the non-sensitive axis direction x causes the output or sensitivity of the first current sensor 1 to increase or decrease.

[0035] The measured current I generates a magnetic field H at the magnetoresistive sensor unit 201a 21 and a magnetic field -H at the magnetoresistive sensor unit 201b 22 ; the output of the magnetoresistive sensor unit 201a is V 21 =[MR / (H k -H x )][(H 21 / I)I - H y ; the output of the magnetoresistive sensor unit 201b is V 22 =[MR / (H k -H x )][-(H 22 / I)I - H y ; the output of the second current sensor 2 is V2 = V 21 -V 22 =[MR / (H k -H x )][(H 21 +H 22 ) / I]I = [MR / (H k -H x )]GI. From the output formula of the second current sensor 2, it can be seen that the external magnetic field H in the non-sensitive axis direction x causes the output or sensitivity of the second current sensor 2 to decrease or increase.

[0036] The average value of the outputs of the first current sensor 1 and the second current sensor 2 is used as the output of the current sensor system. The average value of the outputs of the first current sensor 1 and the second current sensor 2 is V = (V1 + V2) / 2 = (MR / H k ){1 / [1-(H x / H k ) 2}GI. Since H x <<H k , it can be seen that the average value of the outputs of the first current sensor 1 and the second current sensor 2 is hardly affected by the external magnetic field, and thus the average value of the sensitivity is also hardly affected by the external magnetic field.

[0037] Please refer to Figure 2 shown, which is the case of a single current sensor and the present invention under the effective anisotropy field H k = 200 G Figure 1The curve showing the variation of the normalized sensitivity of the current sensor system shown with respect to the magnetic field in the x-direction of the non-sensitive axis. It can be seen that in the case of an external magnetic field of + / -10 G, the sensitivity error of a single current sensor is as high as 5%. In the present invention, Figure 1 the sensitivity error of the current sensor system shown is less than 0.3%. The sensitivity of the current sensor system in the present invention is hardly affected by the external magnetic field, improving the detection accuracy of the current.

[0038] It should be noted that in another embodiment, the first current sensor 1 and the second current sensor 2 may also be non-centrosymmetric, as long as the relative positional relationship between the first current sensor 1 and the second current sensor 2 can achieve: an external magnetic field H in the direction of the non-sensitive axis x causes the output or sensitivity of the first current sensor 1 to increase or decrease; an external magnetic field H in the direction of the non-sensitive axis x causes the output or sensitivity of the second current sensor 2 to decrease or increase; the average value of the outputs of the first current sensor 1 and the second current sensor 2 is hardly affected by the external magnetic field, so that the average value of the sensitivity is also hardly affected by the external magnetic field.

[0039] In summary, the current sensor system 100 in the present invention includes a first current sensor 1 and a second current sensor 2, wherein an external magnetic field H in the direction of the non-sensitive axis x causes the output or sensitivity of the first current sensor 1 to increase or decrease, and the external magnetic field in the direction of the non-sensitive axis causes the output or sensitivity of the second current sensor 2 to decrease or increase. Therefore, the average value of the outputs or sensitivities of the first current sensor 1 and the second current sensor 2 is hardly affected by the external magnetic field.

[0040] The "U-shaped" in this article refers to a generally U-like shape in a broad sense, and does not need to be strictly consistent with the shape of the letter U, and can be deformed to a certain extent.

[0041] In the present invention, words indicating electrical connection such as "connected", "linked", "joined", "connected", etc., without special explanation, indicate direct or indirect electrical connection.

[0042] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modification or change made by those of ordinary skill in the art according to the disclosure of the present invention should be included in the protection scope recorded in the claims.

Claims

1. A current sensor system, characterized in that, It includes: A first current sensor, which includes a first current-carrying conductor and a first magnetic sensor, and the first magnetic sensor is located around the first current-carrying conductor; A second current sensor, which includes a second current-carrying conductor and a second magnetic sensor, and the second magnetic sensor is located around the second current-carrying conductor; Wherein, one end of the first current-carrying conductor is electrically connected to one end of the second current-carrying conductor, and the measured current flows through the first current-carrying conductor and the second current-carrying conductor in sequence, The first current-carrying conductor includes a first leg, a second leg and a first connecting portion. The first leg and the second leg are located on the same side of the first connecting portion. One end of the first leg serves as the other end of the first current-carrying conductor, and the other end of the first leg is connected to one end of the first connecting portion; One end of the second leg serves as one end of the first current-carrying conductor, and the other end of the second leg is connected to the other end of the first connecting portion; The second current-carrying conductor includes a third leg, a fourth leg and a second connecting portion. The third leg and the fourth leg are located on the same side of the second connecting portion. One end of the third leg serves as one end of the second current-carrying conductor, and the other end of the third leg is connected to one end of the second connecting portion; One end of the fourth leg serves as the other end of the second current-carrying conductor, and the other end of the fourth leg is connected to the other end of the second connecting portion; The first magnetic sensor includes a first magnetic sensor unit and a second magnetic sensor unit. The first magnetic sensor unit and the second magnetic sensor unit are located around the first current-carrying conductor to form a differential output; The second magnetic sensor includes a third magnetic sensor unit and a fourth magnetic sensor unit. The third magnetic sensor unit and the fourth magnetic sensor unit are located around the second current-carrying conductor to form a differential output.

2. The current sensor system according to claim 1, wherein An external magnetic field in the non-sensitive axis direction causes the output of the first current sensor to increase or decrease, and an external magnetic field in the non-sensitive axis direction causes the output of the second current sensor to decrease or increase.

3. The current sensor system according to claim 2, wherein The direction of the magnetoresistive moment in the second current sensor is opposite to the direction of the magnetoresistive moment in the first current sensor.

4. The current sensor system according to claim 3, wherein The first current sensor and the second current sensor are centrosymmetric.

5. The current sensor system according to claim 1, wherein Both the first magnetic sensor and the second magnetic sensor are magnetoresistive sensors, The first magnetic sensor unit and the second magnetic sensor unit are respectively located above the first leg and the second leg, and the third magnetic sensor unit and the fourth magnetic sensor unit are respectively located above the third leg and the fourth leg; or The first magnetic sensor unit and the second magnetic sensor unit are respectively located below the first leg and the second leg, and the third magnetic sensor unit and the fourth magnetic sensor unit are respectively located below the third leg and the fourth leg.

6. The current sensor system according to claim 1, wherein the average value of the outputs of the first current sensor and the second current sensor is used as the output of the current sensor system.

7. The current sensor system according to claim 1, characterized in that, It further includes a current connection conductor, one end of the first current-carrying conductor is electrically connected to one end of the second current-carrying conductor via the current connection conductor.

8. The current sensor system according to claim 1, characterized in that It further includes a current input conductor and a current output conductor, the current input conductor is electrically connected to the other end of the first current-carrying conductor; the current output conductor is electrically connected to the other end of the second current-carrying conductor.

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