Current Sensors

Abstract

The input module of the current sensor is connected in parallel with the differential copper bar (1) and the copper bar for current shunt (2). The current to be measured flows through the differential copper bar (1) and the copper bar for current shunt (2), and a magnetic field is generated at the position of the high current and low current detection module (3, 4). In the high current detection module (3), a first magnetic induction module is fixed on the circuit board (5) and placed in the internal gap of the input module, and the first magnetic induction module is composed of at least a first and a second magnetic induction unit (311, 312), and the first and the second magnetic induction units (311, 312) differentially sense the magnetic field of the input module and form an output signal by the first signal output module (32). In the low current detection module (4), the second magnetic induction module is fixed on the circuit board (5) and arranged outside the input module, and the second magnetic induction module is composed of at least a third and a fourth magnetic induction unit (411, 412), which differentially senses the magnetic field of the input module and forms an output signal by the second signal output module (42). The current measurement range can be extended.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate to the technical field of current sensing devices, and in particular to current sensors. [Background technology]

[0002] The current sensor can convert the measured current information into an electrical signal that meets a specific standard according to a specific rule, or other form of information required as output. The current sensor is a detection device that can meet the requirements of information transmission, processing, storage, display, recording, and control.

[0003] At present, widely used current sensors include shunts, current transformers, Rogowski coils, fiber optic current sensors, and magnetic current sensors, which are mainly used in home appliances, smart grids, electric vehicles, wind power generation, and other fields.

[0004] The shunt is based on the principle that when a direct current passes through a standard resistor, a voltage is generated at both ends of the resistor, and is suitable for low frequencies and low power. The shunt has the following disadvantages: there is no electrical insulation between the signal output end and the measured current loop, only a single type of object can be measured, and it is difficult for the shunt to measure large alternating currents. The current transformer is based on the principle of electromagnetic induction and can only measure alternating currents. The Rogowski coil is suitable for measuring alternating currents in a relatively wide frequency range, but cannot measure direct currents. The Rogowski coil has a relatively low sensitivity and is relatively large in size. The optical fiber current sensor is based on the Faraday effect of magneto-optical crystals. The optical fiber current sensor uses an optical fiber, which is sensitive to and capable of detecting external information, as a sensing component. It has a relatively high measurement accuracy and is easy to miniaturize, but requires a special optical fiber that is costly. There are many types of magnetic current sensors. For example, the Hall current sensor has the advantages of mature technology, low cost, high integration, and small size, but the Hall current sensor has low sensitivity, poor temperature drift characteristics, and narrow bandwidth, making it difficult to use the Hall current sensor for high-precision current measurement. Compared with the Hall current sensor, other types of magnetoresistance current sensors have a relatively small saturation magnetic field, resulting in a relatively narrow operating range, and are prone to magnetic saturation during high current measurement, thereby limiting the current measurement range. Summary of the Invention [Problem to be solved by the invention]

[0005] An embodiment of the present invention provides a current sensor for increasing the current measurement range and achieving high-precision detection effect when high or low current is input. [Means for solving the problem]

[0006] One embodiment of the present invention is a current sensor including an input module, a high current detection module, a low current detection module, and a circuit board, The input module includes a differential copper bar and a current shunt copper bar connected in parallel, and a current to be measured flows perpendicular to the cross section of the differential copper bar and the current shunt copper bar to generate a magnetic field at the position of the high current detection module and the low current detection module; The high current detection module includes a first magnetic induction module and a first signal output module, the first magnetic induction module is fixed on the circuit board and disposed in the internal gap of the input module, the first magnetic induction module includes at least a first magnetic sensing unit and a second magnetic sensing unit therein, the first magnetic sensing unit and the second magnetic sensing unit differentially sense the magnetic field of the input module and form an output signal through the first signal output module; the low current detection module includes a second magnetic induction module and a second signal output module, the second magnetic induction module is fixed on the circuit board and disposed outside the input module, the second magnetic induction module includes at least a third magnetic sensing unit and a fourth magnetic sensing unit therein, the third magnetic sensing unit and the fourth magnetic sensing unit differentially sense the magnetic field of the input module and form an output signal through the second signal output module; A current sensor is provided.

[0007] One embodiment of the present invention is a current sensor including an input module, a high current detection module, a low current detection module, and a circuit board, The input module comprises two or more copper bars for current shunting connected in parallel, and a current to be measured flows perpendicular to the cross section of the copper bars for current shunting to generate a magnetic field at the position of the high current detection module and the low current detection module; The high current detection module is located in the internal gap of the input module, and the high current detection module includes a first magnetic induction module and a first signal output module fixed on a circuit board, the first magnetic induction module includes a first magnetic sensing unit, and the first magnetic sensing unit senses the magnetic field of the input module and forms an output signal of the current sensor through the first signal output module; The low-current detection module is located outside the input module, and the low-current detection module includes a second magnetic induction module fixed on a circuit board and a second signal output module, the second magnetic induction module includes a second magnetic sensing unit, and the second magnetic sensing unit senses the magnetic field of the input module and forms an output signal of the current sensor through the second signal output module; A current sensor is also provided.

[0008] In this embodiment of the present invention, the differential copper bar and the current shunt copper bar are connected in parallel to form an input module, and the measured current is shunted. The high current detection module is located in the internal gap of the input module, and the low current detection module is located outside the input module, and the first magnetic induction module and the second magnetic induction module respectively sense the magnetic field of the input module differentially, and then form an output signal through the first signal output module and the second signal output module, thereby realizing that the current sensor differentially senses the differential mode magnetic field generated by the measured current flowing through the input module through the magnetic induction module. In the current sensor provided in this embodiment of the present invention, the shape and distribution of each copper bar can be adjusted to adjust the current input range and sensitivity, so that the current measurement range is large and the current sensor is suitable for magnetic sensing units in different operating ranges. The current sensor can achieve high-precision detection when high or low current is input, and can also measure direct current and / or alternating current. In addition, the input module and the signal output module are electrically isolated, which can improve the resistance ability to external magnetic field interference.

[0009] In order to more clearly show the technical solutions in the embodiments of the present invention or the prior art, the drawings necessary for the embodiments or the prior art are briefly introduced below. The drawings described below are for some specific embodiments of the present invention, but it is obvious to those skilled in the art that the basic concepts of the device structure, driving method and manufacturing method disclosed and evoked by various embodiments of the present invention can be extended and expanded to other structures and drawings, and they should be included in the claims of the present invention. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a current sensor provided in one embodiment of the present invention. [Diagram 2] FIG. 2 is a magnetic field simulation diagram of the stepped differential copper bar of FIG. 1. [Diagram 3] FIG. 2 is a magnetic field simulation diagram of the input module of FIG. 1. [Figure 4] FIG. 2 is a schematic diagram of another current sensor provided in an embodiment of the present invention. [Diagram 5] FIG. 2 is a schematic diagram of a differential half-bridge structure. [Figure 6] Schematic diagram of a differential full-bridge structure. [Figure 7] A schematic diagram of a double push-pull half-bridge differential structure. [Figure 8] A schematic diagram of a double push-pull full-bridge differential structure. [Figure 9] FIG. 2 is a schematic diagram of yet another current sensor provided in an embodiment of the present invention. [Figure 10] FIG. 2 is a schematic diagram of yet another current sensor provided in an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below through implementations with reference to the drawings in the embodiments of the present invention. It is clear that the embodiments described herein are only some embodiments, not all embodiments, of the present invention. Based on the basic concepts disclosed and evoked by the embodiments of the present invention, all other embodiments obtained by those skilled in the art are included in the protection scope of the present invention.

[0012] FIG. 1 shows a schematic diagram of a current sensor provided in one embodiment of the present invention. The current sensor in this embodiment includes an input module, a high current detection module 3, a low current detection module 4, and a circuit board 5. The input module includes a differential copper bar 1 and a current shunt copper bar 2 connected in parallel, and a measured current flows perpendicular to the cross section of the differential copper bar 1 and the current shunt copper bar 2 to generate a magnetic field at the position of the high current detection module 3 and the low current detection module 4. The high current detection module 3 includes a first magnetic induction module and a first signal output module 32, the first magnetic induction module is fixed on the circuit board 5 and disposed in the internal gap of the input module, the first magnetic induction module includes at least a first magnetic sensing unit 311 and a second magnetic sensing unit 312 therein, and the first magnetic sensing unit 311 and the second magnetic sensing unit 312 differentially sense the magnetic field of the input module to form an output signal through the first signal output module 32. The low current detection module 4 includes a second magnetic induction module and a second signal output module 42, where the second magnetic induction module is fixed on the circuit board 5 and disposed outside the input module, and the second magnetic induction module includes at least a third magnetic sensing unit 411 and a fourth magnetic sensing unit 412 therein, where the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 differentially sense the magnetic field of the input module and form an output signal through the second signal output module 42.

[0013] In this embodiment, the input module includes a differential copper bar 1 and a current shunt copper bar 2 connected in parallel. In the cross-sectional view of the current sensor shown in FIG. 1, there is a gap between the differential copper bar 1 and the current shunt copper bar 2. The differential copper bar 1, the current shunt copper bar 2 and the gap between them can be defined as the area of ​​the input module, in which case the gap is the internal gap of the input module. Correspondingly, the periphery of the area of ​​the input module can be defined as the outside of the input module. From this, it can be seen that the high current detection module 3 fixed on the circuit board 5 is located in the internal gap of the input module, i.e., the high current detection module 3 is located between the differential copper bar 1 and the current shunt copper bar 2, and the low current detection module 4 fixed on the circuit board 5 is located outside the input module, and optionally the low current detection module 4 is located outside the side of the current shunt copper bar 2 away from the differential copper bar 1. The cross-sectional view of the current sensor can be understood as a cross-sectional view obtained by cutting the current sensor along a selected plane perpendicular to the differential copper bar 1 and the current shunt copper bar 2.

[0014] The current sensor is used to detect electric current, and the current to be measured flows into the current sensor. Specifically, the current to be measured flows in a cross section perpendicular to the differential copper bar 1 and the current shunt copper bar 2, generating a magnetic field at the position of the high current detection module 3 and also at the position of the low current detection module 4.

[0015] The high current detection module 3 includes a first magnetic induction module (not numbered) and a first signal output module 32, where the first magnetic induction module is fixed on the circuit board 5 and disposed in the internal gap of the input module, i.e., the high current detection module 3 is located between the differential copper bar 1 and the current shunt copper bar 2. As shown in FIG. 1, the first magnetic induction module includes at least a first magnetic sensing unit 311 and a second magnetic sensing unit 312 therein. After the measured current flows into the input module, the first magnetic sensing unit 311 and the second magnetic sensing unit 312 differentially sense the magnetic field of the input module, and the magnetic field signal is processed by the first signal output module 32 to form the output signal of the current sensor.

[0016] The low current detection module 4 includes a second magnetic induction module (not numbered) and a second signal output module 42, where the second magnetic induction module is fixed on the circuit board 5 and disposed outside the input module, and optionally the low current detection module 4 is located on the side of the current shunt copper bar 2 away from the differential copper bar 1. As shown in FIG. 1, the second magnetic induction module includes at least a third magnetic sensing unit 411 and a fourth magnetic sensing unit 412 therein, where the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 are located on the same side outside the input module, and optionally located above the input module and near the current shunt copper bar 2. The third magnetic sensing unit 411 is located within the vertical projection coverage of the current shunt copper bar 2, and the fourth magnetic sensing unit 412 is located outside the vertical projection coverage. The sensitive directions of the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 are both rightward. After the measured current flows into the input module, the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 differentially sense the magnetic field of the input module, and the magnetic field signal is processed by the second signal output module 42 to form the output signal of the current sensor.

[0017] 1 , optionally, the first magnetic sensing unit 311 is located above the differential copper bar 1, and the sensitivity direction of the first magnetic sensing unit 311 is the same as or opposite to the direction of the magnetic field generated in the first magnetic sensing unit 311 by the differential copper bar 1, along the in-plane direction of the first magnetic induction module, and perpendicular to the direction of the measured current. The sensitivity direction of the second magnetic sensing unit 312 is the same as the sensitivity direction of the first magnetic sensing unit 311, and the distance between the second magnetic sensing unit 312 and the differential copper bar 1 is greater than the distance between the first magnetic sensing unit 311 and the differential copper bar 1.

[0018] Optionally, the differential copper bar 1 is in a step shape near the first magnetic induction module, and includes at least a first step 11 and a second step 12. The first magnetic sensing unit 311 is located above the first step 11, and the second magnetic sensing unit 312 is located above the second step 12. The sensitivity direction of the first magnetic sensing unit 311 is the same as or opposite to the direction of the magnetic field generated in the first magnetic sensing unit 311 by the differential copper bar 1, along a direction in the plane of the first magnetic induction module, and perpendicular to the direction of the current to be measured. The sensitivity direction of the second magnetic sensing unit 312 is the same as or opposite to the direction of the magnetic field generated in the second magnetic sensing unit 312 by the differential copper bar 1, along a direction in the plane of the second magnetic induction module, and perpendicular to the direction of the current to be measured.

[0019] Specifically, as shown in FIG. 1, a differential copper bar 1 with a stepped cross section and a current shunt copper bar 2 with a rectangular cross section are used, and the two are connected in parallel and shunted to form an input module, and there is a gap between the differential copper bar 1 and the current shunt copper bar 2. The side of the stepped differential copper bar 1 facing the current shunt copper bar 2 is stepped, and its cross-sectional view includes a first stage 11 and a second stage 12, as shown in FIG. 1. The first magnetic sensing unit 311 is located in the magnetic field uniform region above the first stage 11, and the second magnetic sensing unit 312 is located in the magnetic field uniform region above the second stage 12. Both the first magnetic sensing unit 311 and the second magnetic sensing unit 312 are located in the magnetic field uniform region of the current shunt copper bar 2, and their sensitivity directions are both to the right.

[0020] Figure 2 shows the magnetic field simulation diagram of the stepped differential copper bar. The measured current I in Assume that the current is 50A and the cross-sectional width of the stepped differential copper bar 1 is 10mm. When the measured current flows into the input module, a magnetic field is generated in the horizontal plane 0.6mm above the differential copper bar 1. As shown in Figure 2, it can be seen that near the step rising section of the differential copper bar 1, there is obvious difference between the magnetic fields in the same plane above the first step 11 and the second step 12, and the magnetic field distribution is relatively uniform.

[0021] Figure 3 shows the magnetic field simulation diagram of the input module. Based on the differential copper bar 1, the current shunt copper bar 2 with a cross-sectional width of 10 mm is introduced, and the current shunt copper bar 2 is connected in parallel with the differential copper bar 1. The magnetic field simulation calculation result of the input module is shown in Figure 3. Compared with Figure 2, it can be seen that the shape of the magnetic field distribution of the input module remains almost the same, but the whole curve shows an obvious downward shift, that is, the magnetic field is reduced.

[0022] Measured current I in can flow perpendicular to the cross section of the input module, and the current direction in FIG. 1 is inward, perpendicular to the plane of the paper. The current passing through the first stage 11 is denoted by I 11, the current passing through the second stage 12 is I 12 If we assume that the current passing through the copper bar 2 for current shunt is I2, the current I1 flowing through the differential copper bar 1 is I1=I 11 +I 12 The first magnetic sensing unit 311 and the second magnetic sensing unit 312 are located in the magnetic field uniform region of the current shunt copper bar 2, and these copper bars are made of the same material, in which case, formula (1) is obtained. I in =I 11 +I 12 +I2(1)

[0023] For ease of analysis and calculation, the entire first stage 11 and the second stage 12 can be subdivided into upper and lower rectangular cross-sectional parts according to the height of the second stage 12. The height of the lower rectangle divided by the differential copper bar 1 is equal to the height of the second stage 12, and the width of the lower rectangle is the sum of the first stage 11 and the second stage 12. The height of the upper rectangle divided by the differential copper bar 1 is the difference in height between the first stage 11 and the second stage 12, and the width of the upper rectangle is equal to the first stage 11. In that case, the first magnetic sensing unit 311 and the second magnetic sensing unit 312 are located above the lower rectangle, and the first magnetic sensing unit 311 is located above the upper rectangle. It can be concluded that the first magnetic sensing unit 311 and the second magnetic sensing unit 312 are located within the magnetic field uniform region of the lower rectangle, and the first magnetic sensing unit 311 is located within the magnetic field uniform region of the upper rectangle.

[0024] Based on this, the current I1 flowing through the stepped differential copper bar 1 can be divided into the current I'1 of the lower rectangle and the current ΔI1 of the upper rectangle, in which case equations (2) and (3) are obtained. I = I'1 + ΔI1(2) I in =I'1+ΔI1+I2(3)

[0025] If the horizontal right direction shown in FIG. 1 is regarded as the forward direction of the magnetic field, according to Biot-Savart's law for the magnetic field generated by a current-carrying conductor, the magnetic field H generated at the position of the first magnetic sensing unit 311 by the current I1 in the stepped differential copper bar 1 is 211 and the magnetic field H generated at the position of the second magnetic sensing unit 312. 212 respectively vary linearly with the current, in which case we obtain equation (4). H 211 =k1I'1+k 21 ΔI1-k3I2; H 212 =k1I'1+k 22 ΔI1-k3I2(4) In the above formula, k1 is the linear constant of the uniform magnetic field generated at the position of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 by the current I'1 of the lower rectangle, k3 is the linear constant of the uniform magnetic field generated at the position of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 by the current I2 of the copper bar for current shunting, and k 21 is the linear constant of the magnetic field generated at the position of the first magnetic sensing unit 311 by the current ΔI1 of the upper rectangle, and k 22 is the linear constant of the magnetic field generated at the position of the second magnetic sensing unit 312 by the current ΔI1 in the upper rectangle.

[0026] By performing an equivalent transformation on Equation (4), the magnetic field at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 is expressed as a common mode magnetic field H CM and the differential mode magnetic field H DM In this case, equation (5) is obtained.

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[0027] Accordingly, the magnetic field at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 is expressed as a common mode magnetic field H CM and the differential mode magnetic field H DM can be converted to a superposition representation of H 211 =H CM +H DM (6) H 212 =H CM -H DM

[0028] From equation (5) and Fig. 1, it can be seen that the direction of the magnetic field generated by the current I'1 of the lower rectangle at the position of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 is opposite to that of the magnetic field generated by the current I2 of the current shunting copper bar at the position of the first magnetic sensing unit 311 and the second magnetic sensing unit 312, and the two can be cancelled out. Specifically, the magnetic field generated by the current I'1 of the lower rectangle at the position of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 at the position of the current shunting copper bar is k1I'1, and the magnetic field generated by the current I2 of the current shunting copper bar at the position of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 is K3I2, and the two can be reduced or reduced, i.e., k1I'1-k3I2, or even return to zero after cancellation, such as k1I'1-k3I2=0.

[0029] In that case, after cancellation, the common mode magnetic field H CMand the magnetic field generated by the single differential copper bar 1 can be in the same direction, zero, or opposite directions. The magnetic field generated by the single differential copper bar 1 can be understood to be the magnetic field generated at the position of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 by the current ΔI1 of the upper rectangle in the differential copper bar 1. Furthermore, the current I′1 of the lower rectangle and the current I2 of the current shunt copper bar generate a common mode magnetic field H CM It generates only the differential mode magnetic field H DM , thereby achieving the effect of adjusting and increasing the input range of the current that can be measured by the current sensor.

[0030] Furthermore, it can be seen that in the low current detection module 4, unlike the situation in the previous analysis, where the magnetic fields generated by the differential copper bar 1 and the current shunt copper bar 2 at the location of the high current detection module 3 are in opposite directions and therefore cancel or subtract each other according to the Biot-Savart law for the magnetic field generated by a current carrying conductor, the low current detection module 4 is located outside the input module consisting of the differential copper bar 1 and the current shunt copper bar 2. Optionally, the low current detection module 4 is located on the side of the current shunt copper bar 2 away from the differential copper bar 1, i.e. in an upper position outside the input module. In other embodiments, optionally, the low current detection module can also be located on the side of the differential copper bar away from the current shunt copper bar, i.e. in a lower position outside the input module. Thus, the magnetic fields generated in the low current detection module 4 by the differential copper bar 1 and the current shunt copper bar 2 have the same direction.

[0031] In Fig. 1, the magnetic fields generated by the differential copper bar 1 and the current shunt copper bar 2 at the position of the third magnetic sensing unit 411 in the low current detection module 4 have the same direction, in which case the two can be superimposed and multiplied, thereby generating a larger magnetic field in the low current case to ensure a more accurate detection of the measured low current. The input range of the current that can be measured by the current sensor is extended.

[0032] Optionally, the number of the current shunt copper bars is one or more, where any current shunt copper bar is located above the first magnetic induction module or below the differential copper bar, and the vertical projection range of any current shunt copper bar covers the first magnetic sensing unit and the second magnetic sensing unit in the first magnetic induction module. As shown in FIG. 1, optionally, the number of the current shunt copper bar 2 is one, where the current shunt copper bar is located above the first magnetic induction module, and the vertical projection range of the current shunt copper bar 2 covers the first magnetic sensing unit 311 and the second magnetic sensing unit 312 in the first magnetic induction module.

[0033] FIG. 4 shows a schematic diagram of another current sensor provided in an embodiment of the present invention. As shown in FIG. 4, optionally, the differential copper bar 1 is located inside the circuit board 5. Optionally, the number of current shunt copper bars is two, where the current shunt copper bar 21 is located below the differential copper bar 1, the current shunt copper bar 22 is located above the first magnetic induction module, and the vertical projection range of the current shunt copper bars 21 and 22 covers the first magnetic sensing unit 311 and the second magnetic sensing unit 312 in the first magnetic induction module. The input module consists of a differential copper bar 1 with a rectangular cross section and two current shunt copper bars 21 and 22 with rectangular cross sections, which are connected in parallel and shunted. The two rectangular current shunt copper bars 21 and 22 are arranged opposite to each other, and the rectangular differential copper bar 1 is located in the gap between the two rectangular current shunt copper bars 21 and 22. The high current detection module 3 is disposed in the gap between the rectangular differential copper bar 1 and the rectangular current shunt copper bar 22. The rectangular differential copper bar 1 is located near one side of the first magnetic sensing unit 311 and above the current shunt copper bar 21.

[0034] Based on this, the first magnetic sensing unit 311 and the second magnetic sensing unit 312 are located in the magnetic field uniform region of the copper bar 21 for current shunting, and are also located in the magnetic field uniform region of the copper bar 22 for current shunting, and both have their sensitivity directions pointing to the right. The first magnetic sensing unit 311 is located in the magnetic field uniform region of the differential copper bar 1. In that case, the analysis and calculation process of this input module is similar to that of the input module consisting of the stepped differential copper bar 1 and the rectangular current shunting copper bar 2 shown in FIG. 1. Therefore, the current of the rectangular differential copper bar 1 in FIG. 4 can be compared to the current ΔI1 of the upper rectangle in FIG. 1, and the current of the copper bar 21 for current shunting in FIG. 4 can be compared to the current I'1 of the lower rectangle in FIG. 1.

[0035] Since both the first magnetic sensing unit 311 and the second magnetic sensing unit 312 are assumed to be located within the magnetic field uniform regions of the current shunt copper bar 21 and the current shunt copper bar 22, equations (1) to (6) remain valid when there is a gap between the differential copper bar 1 and the current shunt copper bar 21.

[0036] As described above, from equations (5) and (6), the magnetic field at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 is expressed as the measured current I in The measured current is directly proportional to the differential mode magnetic field H DM It can be seen that the measurement can be done by measuring the common mode magnetic field H. Analysis and calculation of copper bars for multiple current shunts is done by measuring the k3I2 term and the common mode magnetic field H CM The analysis process is roughly the same as above, except for the adjustment of

[0037] Furthermore, under ideal conditions, the common-mode magnetic field H CM are completely cancelled out, in which case we obtain equations (7) and (8).

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[0038] Furthermore, under ideal conditions, the magnetic field generated by ΔI1 at the position of the second magnetic sensing unit 312 is very small, so k 22 = 0, and therefore, equations (7-8) can be simplified to equations (9-10). H CM =0

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[0039] That is, the magnetic field at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 is in The measured current is directly proportional to the differential mode magnetic field H DM It can be measured by measuring

[0040] Combining equations (9) and (10), under ideal conditions, the common-mode magnetic field H CM are completely cancelled out, i.e., the measured current is completely offset by the differential mode magnetic field H DM It can be seen that only the differential mode magnetic field H DM The magnitude of the differential mode magnetic field H is adjusted by the shape of the copper bar in the input module. DM The magnitude of can be made to completely match the linear operating range of the magnetoresistive sensing component, so that the current measurement range of the current sensor can reach its maximum.

[0041] As mentioned above, the high current detection module 3 uses differential measurement of the differential mode magnetic field generated by the input module, and the high current detection module 3 partially or completely cancels the common mode magnetic field, which can effectively solve the problem that the magnetoresistance sensing component is easily saturated, and furthermore, adjusts and extends the current measurement range, and brings about good resistance ability to external magnetic field interference. As a result, the current sensor is suitable for current detection in various operating ranges.

[0042] Optionally, the current sensor further includes a switching module 6. The switching module 6 selects whether to switch to the high current detection module 3 or the low current detection module 4 according to the range of the measured current. The input module, the high current detection module 3, the low current detection module 4, and the switching module 6 are electrically isolated from each other. Optionally, a dielectric isolation layer is used to electrically isolate these modules from each other. When the switching module 6 switches to the high current detection module 3, the high current detection module 3 operates, and then the current sensor can be used to measure the high current. When the switching module 6 switches to the low current detection module 4, the low current detection module 4 operates, and then the current sensor can be used to measure the low current.

[0043] Optionally, the current sensor further includes a mechanical support housing 7. The mechanical support housing 7 serves to cover, secure and support the internal parts of the current sensor and provide an external interface.

[0044] In this embodiment of the present invention, the differential copper bar and the current shunt copper bar are connected in parallel to form an input module, and the measured current is shunted. The high current detection module is located in the internal gap of the input module, and the low current detection module is located outside the input module, and the first magnetic induction module and the second magnetic induction module respectively sense the magnetic field of the input module differentially, and then form an output signal through the first signal output module and the second signal output module, thereby realizing that the current sensor differentially senses the differential mode magnetic field generated by the measured current flowing through the input module through the magnetic induction module. In the current sensor provided in this embodiment of the present invention, the shape and distribution of each copper bar can be adjusted to adjust the current input range and sensitivity, so that the current measurement range is large and the current sensor is suitable for magnetic sensing units in different operating ranges. The current sensor can achieve high-precision detection when high or low current is input, and can also measure direct current and / or alternating current. In addition, the input module and the signal output module are electrically isolated, which can improve the resistance ability to external magnetic field interference.

[0045] Optionally, the first magnetic sensing unit and the second magnetic sensing unit in the first magnetic induction module are connected to form one of a differential half-bridge structure, a differential full-bridge structure, a double push-pull half-bridge differential structure, and a double push-pull full-bridge differential structure, and the third magnetic sensing unit and the fourth magnetic sensing unit in the second magnetic induction module are connected to form one of a differential half-bridge structure, a differential full-bridge structure, a double push-pull half-bridge differential structure, and a double push-pull full-bridge differential structure.

[0046] In the differential half-bridge structure, each magnetic sensing unit includes one magnetoresistance bridge arm, and the two magnetoresistance bridge arms in the same magnetic induction module are electrically differentiated together to form a differential half-bridge structure.

[0047] In the differential full-bridge structure, each magnetic sensing unit includes two magnetoresistance bridge arms, and the two magnetoresistance bridge arms in the same magnetic sensing unit are located on two opposite bridge arms, and the two magnetoresistance bridge arms of different magnetic sensing units are located on two adjacent bridge arms to form a differential full-bridge structure, and the output signal of the magnetic induction module is the differential signal of the differential full-bridge structure.

[0048] In the double push-pull half-bridge differential structure, two magnetic sensing units in the same magnetic induction module both include two magnetic resistance bridge arms, the two magnetic resistance bridge arms in each magnetic sensing unit have opposite sensitivity directions, the two magnetic resistance bridge arms in the magnetic sensing units are upper and lower bridge arms, forming a push-pull half-bridge structure, the sensitivity directions of the upper bridge arms in the two magnetic sensing units are the same, and the sensitivity directions of the lower bridge arms in the two magnetic sensing units are the same, the two magnetic sensing units in the same magnetic induction module collectively form a double push-pull half-bridge differential structure, and the output signal of the magnetic induction module is the differential signal of the double push-pull half-bridge differential structure.

[0049] In the double push-pull full-bridge differential structure, two magnetic sensing units in the same magnetic induction module both include four magnetoresistance bridge arms, the four magnetoresistance bridge arms of the magnetic sensing units form a push-pull full-bridge structure, the sensitivity directions of the two magnetic sensing units in the same magnetic induction module are the same, the two magnetic sensing units in the same magnetic induction module form a double push-pull full-bridge differential structure as a whole, and the output signal of the magnetic induction module is a differential signal of the double push-pull full-bridge differential structure. The magnetoresistance bridge arms are formed by connecting one or more magnetoresistance sensing components in series and in parallel.

[0050] Optionally, there are two device options for the two magnetic sensing units in the same magnetic induction module: (1) the two magnetic sensing units are comprised of one of a magnetic sensing component including a fluxgate, a magnetic sensing component including a giant magneto-impedance (GMI) device, and a magnetic sensing component including a magneto-electric coupling device (ME), and (2) the magnetoresistance sensing component forming the differential structure in the two magnetic sensing units is comprised of one of an anisotropic magnetoresistance (AMR) device, a giant magnetoresistance (GMR) device, a tunneling magnetoresistance (TMR) device, and a colossal magnetoresistance (CMR) device.

[0051] FIG. 5 shows a schematic diagram of a differential half-bridge structure. As shown in FIG. 5, a single bridge with a differential half-bridge structure is used in the high current detection module 3. Specifically, the first magnetic sensing unit 311 and the second magnetic sensing unit 312 in the first magnetic induction module are connected to form a differential half-bridge structure. In the differential half-bridge structure, the first magnetic sensing unit 311 includes a magnetoresistive bridge arm 311a, and the second magnetic sensing unit 312 includes a magnetoresistive bridge arm 312a. The two magnetoresistive bridge arms 311a and 312a in the first magnetic induction module are connected together and electrically differentiated to form a differential half-bridge structure, where the sensitivity directions of the two magnetoresistive bridge arms 311a and 312a are the same and are horizontally rightward. Optionally, the magnetoresistive bridge arm is composed of one or more magnetoresistive sensing components, and the magnetoresistive sensing components in the magnetoresistive bridge arms 311a and 312a are TMR devices.

[0052] According to the above analysis and calculation, as well as the schematic diagram of the differential half-bridge structure shown in FIG. 5, in the case shown in FIG. 1, the common mode magnetic field generated after the differential copper bar 1 and the current shunt copper bar 2 are cancelled out, and the horizontal rightward magnetic field generated by the differential copper bar 1 at the position of the first magnetic induction module can be in the same direction, zero, or opposite directions.

[0053] After the cancellation, the direction of the common mode magnetic field generated after the differential copper bar 1 and the copper bar for current shunt 2 are cancelled is horizontally rightward. In other words, after the cancellation, the common mode magnetic field and the magnetic field generated at the position of the first magnetic induction module by the differential copper bar 1 are in the same direction. For example, the differential mode magnetic field H DM5, the rightward magnetic field at the position of the first magnetic sensing unit 311 is larger than the rightward magnetic field at the position of the second magnetic sensing unit 312. In FIG. 5, the sensitivity directions of the two magnetoresistance bridge arms 311a and 312a are both rightward, so the rightward magnetic field at the position of the magnetoresistance bridge arm 311a is larger than the magnetic field at the position of the magnetoresistance bridge arm 312a. As a result, the resistance value of the magnetoresistance bridge arm 311a is less than the resistance value of the magnetoresistance bridge arm 312a, thereby realizing the change from the magnetic field to a voltage. Therefore, Vout in FIG. 5 changes accordingly according to the situation of the measured current to form a differential voltage signal.

[0054] FIG. 6 shows a schematic diagram of a differential full-bridge structure. As shown in FIG. 6, a single bridge with a differential full-bridge structure is used in the low current detection module 4. Specifically, the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 in the second magnetic induction module are connected to form a differential full-bridge structure. In the differential full-bridge structure, the third magnetic sensing unit 411 includes two magnetoresistance bridge arms 411a and 411b, and the fourth magnetic sensing unit 412 includes two magnetoresistance bridge arms 412a and 412b. The sensitivity directions of the four magnetoresistance bridge arms 411a, 411b, 412a, and 412b in the second magnetic induction module are completely the same, horizontally rightward, and electrically connected to form an identical differential full-bridge structure. Optionally, the magnetoresistance bridge arm is composed of one or more magnetoresistance sensing components, and the magnetoresistance sensing component in each magnetoresistance bridge arm is a TMR device.

[0055] As shown in Fig. 1 and Fig. 6, the rightward magnetic field in the third magnetic sensing unit 411 is larger than the rightward magnetic field in the fourth magnetic sensing unit 412. Because the sensitivity directions of the four magnetoresistive bridge arms 411a, 411b, 412a, and 412b are all rightward, the rightward magnetic field in the magnetoresistive bridge arms 411a and 411b is larger than the rightward magnetic field in the magnetoresistive bridge arms 412a and 412b, and in this case, the resistance values ​​of the magnetoresistive bridge arms 411a and 411b are smaller than the resistance values ​​of the magnetoresistive bridge arms 412a and 412b. Based on this, it can be concluded that in Fig. 6, the voltage V2 is larger than the voltage V1, thereby forming a differential voltage signal.

[0056] FIG. 7 shows a schematic diagram of a double push-pull half-bridge differential structure. As shown in FIG. 4 and FIG. 7, the high current detection module 3 uses a double push-pull half-bridge differential structure for differentiation. Specifically, the first magnetic sensing unit 311 and the second magnetic sensing unit 312 in the first magnetic induction module are connected to form a double push-pull half-bridge differential structure. The first magnetic sensing unit 311 includes two magnetoresistance bridge arms 311a1 and 311a2, and the two bridge arms form a first push-pull half-bridge structure, in which the sensitivity direction of the magnetoresistance bridge arm 311a1 is to the left, and the sensitivity direction of the magnetoresistance bridge arm 311a2 is to the right. The second magnetic sensing unit 312 includes two magnetoresistive bridge arms 312a1 and 312a2, which form a second push-pull half-bridge structure, where the sensitivity direction of the magnetoresistive bridge arm 312a1 is to the left and the sensitivity direction of the magnetoresistive bridge arm 312a2 is to the right. Optionally, the magnetoresistive bridge arms are made of one or more magnetoresistive sensing components, which are GMR devices.

[0057] 1 and 7, assuming that the direction is rightward after the common mode magnetic field is cancelled and the rightward magnetic field in the first magnetic sensing unit 311 is greater than the rightward magnetic field in the second magnetic sensing unit 312 after the differential mode magnetic field is superimposed, the resistance of the magnetoresistance bridge arm 311a1 is greater than the resistance of the magnetoresistance bridge arm 311a2, the resistance of the magnetoresistance bridge arm 312a1 is greater than the resistance of the magnetoresistance bridge arm 312a2, and the resistance difference between the magnetoresistance bridge arms 311a1 and 311a2 is greater than the resistance difference between the magnetoresistance bridge arms 312a1 and 312a2, thereby realizing the change from magnetic field to voltage. On this basis, V1a and V2a in FIG. 7 change accordingly according to the situation of the measured current to form a differential voltage signal.

[0058] Figure 8 shows a schematic diagram of a double push-pull full-bridge differential structure. Referring to Figure 4 and Figure 8, the low current detection module 4 uses a double push-pull full-bridge differential structure for differentiation. Specifically, the third magnetic sensing unit 411 includes four magnetoresistance bridge arms 411b1, 411b2, 411b3, and 411b4 therein, forming a push-pull full-bridge structure, where the sensitivity directions of the magnetoresistance bridge arms 411b2 and 411b3 are both leftward, and the sensitivity directions of the magnetoresistance bridge arms 411b1 and 411b4 are both rightward. The fourth magnetic sensing unit 412 includes four magnetoresistive bridge arms 412b1, 412b2, 412b3, and 412b4 therein, forming another push-pull full bridge structure, where the sensitivity directions of the magnetoresistive bridge arms 412b2 and 412b3 are both leftward and the sensitivity directions of the magnetoresistive bridge arms 412b1 and 412b4 are both rightward. The magnetoresistive sensing components forming the magnetoresistive bridge arms are GMR devices.

[0059] 4 and 8, the third magnetic sensing unit 411 is mainly affected by the right-handed magnetic field generated by the current shunt copper bar 22, and the fourth magnetic sensing unit 412 is mainly affected by the left-handed magnetic field generated by the current shunt copper bar 21. In FIG. 8, the voltage difference between V1b1 and V1b2 forms the output signal of the third magnetic sensing unit 411, and the voltage difference between V2b1 and V2b2 forms the output signal of the fourth magnetic sensing unit 412. Due to the characteristics of the double push-pull full-bridge differential structure, it can be concluded that the differential voltage signal of the above two push-pull full-bridge structures changes linearly with the measured current.

[0060] Optionally, the first signal output module and the second signal output module each include an open-loop signal conditioning circuit using an open-loop circuit or a closed-loop signal conditioning circuit using a closed-loop circuit and a feedback coil.

[0061] In the open-loop circuit, the first signal output module or the second signal output module uses an open-loop signal conditioning circuit, and the signal output module uses the open-loop signal conditioning circuit to perform conditioning amplification, temperature compensation, and linearity correction on the differential signals of the two magnetic sensing units in the module. The open-loop signal conditioning circuit is one of a printed circuit board (PCB) level discrete component circuit or an application specific integrated circuit (ASIC).

[0062] In the closed loop circuit, the first signal output module or the second signal output module uses a closed loop signal conditioning circuit and a feedback coil, and the signal output module uses the closed loop signal conditioning circuit and the feedback coil to perform conditioning amplification, temperature compensation, and linearity correction on the differential signals of the two magnetic sensing units in the module. The closed loop signal conditioning circuit, the feedback coil, and the magnetic sensing unit in the high current detection module or the low current detection module form a closed loop magnetic field feedback, and the differential signals of the two magnetic sensing units in the module are amplified, and then a feedback magnetic field is generated through the feedback coil to cancel the differential mode magnetic field in the opposite direction. When the dynamic balance of the magnetic field is reached, the two magnetic sensing units in the module operate at an equal common mode magnetic field operating point, and the feedback current of the feedback coil is sampled through the sampling resistor to form the output signal of the magnetic induction module.

[0063] The closed loop signal conditioning circuit is either a PCB level discrete component circuit or an ASIC. The feedback coil is integrated within the closed loop signal conditioning circuit, circuit board, magnetic sensing unit, ASIC, or magnetic induction module.

[0064] In this embodiment, the first signal output module and the second signal output module each include an open-loop signal conditioning circuit using an open-loop circuit, or a closed-loop signal conditioning circuit using a closed-loop circuit and a feedback coil. That is, in one particular embodiment of the present invention, the first signal output module and the second signal output module can both include an open-loop signal conditioning circuit using an open-loop circuit, or the first signal output module and the second signal output module can both include a closed-loop signal conditioning circuit using a closed-loop circuit and a feedback coil, or the first signal output module can include an open-loop signal conditioning circuit using an open-loop circuit and the second signal output module includes a closed-loop signal conditioning circuit using a closed-loop circuit and a feedback coil, or the first signal output module can include a closed-loop signal conditioning circuit using a closed-loop circuit and a feedback coil, and the second signal output module includes an open-loop signal conditioning circuit using an open-loop circuit.

[0065] Take the first signal output module using a closed loop circuit in the high current detection module as an example. The first signal output module includes a closed loop signal conditioning circuit and a feedback coil. The closed loop signal conditioning circuit, the feedback coil and the magnetic sensing unit in the module form a closed loop magnetic field feedback. The magnetic field feedback coil can be integrated into the closed loop signal conditioning circuit, or integrated into the circuit board, or integrated into the magnetic sensing unit, or can use ASIC, or can be integrated into the magnetic induction module. Regardless of where the magnetic field feedback coil is integrated, the principle of the magnetic field closed loop negative feedback is roughly the same.

[0066] In the first signal output module, the closed-loop signal conditioning circuit and the feedback coil are used to perform conditioning amplification, temperature compensation, and linearity correction on the differential voltage signal. The closed-loop signal conditioning circuit amplifies the differential voltage signal, and then drives the feedback coil to generate a feedback magnetic field so as to counteract the differential mode magnetic field. When the magnetic field reaches dynamic equilibrium, the first magnetic sensing unit and the second magnetic sensing unit operate at an equal common mode magnetic field operating point, and the feedback current of the feedback coil is sampled through the sampling resistor to form the output of the first magnetic induction module. Optionally, the closed-loop signal conditioning circuit is a PCB-level discrete component circuit.

[0067] As shown in FIG. 1, the first signal output module 32 in the high current detection module 3 includes a magnetic field feedback coil, which is integrated in the first magnetic induction module. In this case, the reference number 32 can be equal to the magnetic field feedback coil in the first signal output module. The plane in which the magnetic field feedback coil 32 is located is parallel to the plane in which the first magnetic sensing unit 311 and the second magnetic sensing unit 312 are located. The cross section of the magnetic field feedback coil 32 is symmetrically distributed along both sides of the midline. The current direction on one side of the midline is outward perpendicular to the paper plane, and the current direction on the other side of the midline is inward perpendicular to the paper plane.

[0068] Regarding the direction of the feedback magnetic field generated by the magnetic field feedback coil 32, taking the case where the rightward magnetic field in the first magnetic sensing unit 311 is larger than the rightward magnetic field in the second magnetic sensing unit 312 as an example, in order to cancel the differential mode magnetic field in the opposite direction, in the plan view shown in Fig. 1, optionally, the current direction of the cross section of the conductor horizontally arranged to the left of the midline of the magnetic field feedback coil 32, i.e., below the first magnetic sensing unit 311, is outward perpendicular to the paper plane, and the current direction of the cross section of the conductor horizontally arranged to the right of the midline of the magnetic field feedback coil 32, i.e., below the second magnetic sensing unit 312, is inward perpendicular to the paper plane. As a result, a leftward feedback magnetic field is generated in the first magnetic sensing unit 311, and a rightward feedback magnetic field is generated in the second magnetic sensing unit 312, thereby canceling the differential mode magnetic field in the opposite direction, and finally achieving dynamic equilibrium of the magnetic field.

[0069] As shown in Figure 4, the magnetic field feedback coil 32 is integrated in the magnetic sensing unit in the module, and the magnetic field feedback coil 42 is integrated in the magnetic sensing unit in the module. The position of the feedback coil is not limited to the position shown in the above figure. Although the distribution or connection of the magnetic field feedback coil is slightly different, the principle of magnetic field feedback is the same, and both modules use the distribution of the magnetic field feedback coil to generate a magnetic field in the opposite direction to cancel the differential mode magnetic field.

[0070] Similarly, the low current detection module 4 includes a second signal output module, which uses a closed-loop signal conditioning circuit and a feedback coil 42. The circuit structure and the principle of magnetic field feedback of the low current detection module 4 are approximately the same as those of the high current detection module 3, and will not be described in detail. Optionally, the feedback coil 42 is integrated into the second magnetic induction module, but the location of the feedback coil is not limited thereto.

[0071] In this embodiment, the current sensor can achieve high-precision detection when high or low current is input, can effectively solve the problem of magnetoresistance sensing components being easily saturated, is suitable for magnetic sensing units in various linear operating ranges, brings good resistance ability to external magnetic field interference, has the characteristics of being able to measure large direct and alternating currents, as well as the characteristics of electrically isolated input and output. Coupled with the characteristics of small size, large signal amplitude, high sensitivity, low noise, and easy integration with semiconductor circuits of the TMR device, the design of the back-end signal processing circuit of the current sensor can be further simplified, the size of the entire current sensor can be reduced, and the cost of the current sensor can be reduced.

[0072] Optionally, the third magnetic sensing unit and the fourth magnetic sensing unit in the second magnetic induction module are arranged in the following two ways: (1) the third magnetic sensing unit is located above the input module, and the fourth magnetic sensing unit is located below or to the side of the input module, and the sensitivity directions of the third magnetic sensing unit and the fourth magnetic sensing unit are the same; (2) the third magnetic sensing unit and the fourth magnetic sensing unit are located on the same side of the input module, and the third magnetic sensing unit is located perpendicular to the current shunt copper bar or differential copper bar closest to the third magnetic sensing unit. The third magnetic sensing unit is located within the projection coverage range, and the sensitivity direction of the third magnetic sensing unit is either the same as or opposite to the direction of the magnetic field generated at the position of the third magnetic sensing unit by the current shunt copper bar or differential copper bar closest to the third magnetic sensing unit, along a direction in the plane of the second magnetic induction module and perpendicular to the direction of the current to be measured; and the fourth magnetic sensing unit is located outside the vertical projection coverage range of the current shunt copper bar and the differential copper bar, and the sensitivity direction of the fourth magnetic sensing unit is the same as the sensitivity direction of the third magnetic sensing unit.

[0073] As shown in FIG. 1, the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 are located on the same side relative to the input module, and are optionally close to the current shunt copper bar 2 and away from the differential copper bar 1. The third magnetic sensing unit 411 is located within the vertical projection coverage range of the current shunt copper bar 2, the sensitivity direction of the third magnetic sensing unit 411 is the same as or opposite to the direction of the magnetic field generated by the current shunt copper bar 2 at the position of the third magnetic sensing unit 411, and the sensitivity direction is along the direction in the plane of the second magnetic induction module and perpendicular to the direction of the measured current. The fourth magnetic sensing unit 412 is located outside the vertical projection coverage range of the current shunt copper bar 2, and the sensitivity direction of the fourth magnetic sensing unit 412 is the same as the sensitivity direction of the third magnetic sensing unit 411.

[0074] As shown in FIG. 4, the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 are located on different sides of the input module. Optionally, the third magnetic sensing unit 411 is located above the input module, and the fourth magnetic sensing unit 412 is located below or to the side of the input module. The sensitivity directions of the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 are the same, and both are to the right. Specifically, the third magnetic sensing unit 411 is located in the uniform magnetic field area above the outside of the input module, and the fourth magnetic sensing unit 412 is located in the uniform magnetic field area below the outside of the input module. The magnetic fields generated by the differential copper bar 1 and the current shunt copper bars 21 and 22 at the positions of the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 of the low current detection module 4 are superimposed and increased, thereby generating a larger magnetic field in the case of low current, and ensuring more accurate detection of the measured low current.

[0075] Optionally, the current sensor further includes a third current detection module, and the third current detection module includes a third magnetic induction module and a third signal output module. The third magnetic induction module is composed of a first magnetic sensing unit or a second magnetic sensing unit in the first magnetic induction module, and a third magnetic sensing unit or a fourth magnetic sensing unit in the second magnetic induction module, and the two magnetic sensing units in the third magnetic induction module differentially sense the magnetic field of the input module to form an output signal of the current sensor through the third signal output module.

[0076] As shown in FIG. 4, optionally, the current sensor further includes a third current detection module 8, and the third current detection module 8 includes a third magnetic induction module and a third signal output module. The third magnetic induction module includes two magnetic sensing units, where the second magnetic sensing unit 312 in the first magnetic induction module is multiplexed as one magnetic sensing unit in the third magnetic induction module, and the third magnetic sensing unit 411 in the second magnetic induction module is multiplexed as another magnetic sensing unit in the third magnetic induction module. Optionally, the second magnetic sensing unit 312 has a push-pull half-bridge structure, and the third magnetic sensing unit 411 has a push-pull full-bridge structure. The second magnetic sensing unit 312 and the third magnetic sensing unit 411 differentially sense the magnetic field of the input module to form an output signal of the current sensor through the third signal output module.

[0077] In this embodiment, a differential copper bar 1 with a rectangular cross section and two current shunt copper bars 21 and 22 with a rectangular cross section are connected in parallel to shunt the measured current. The current input range and sensitivity of the current sensor can be adjusted by adjusting the shape and distribution of each copper bar. The high current detection module 3 uses a double half-bridge structure with two push-pull half bridges for differentiation, and the low current detection module 4 uses a double full-bridge structure with a push-pull full bridge for differentiation. In addition, a third magnetic sensing unit 411 is located in the magnetic field uniform region above the outside of the input module, and a fourth magnetic sensing unit 412 is located in the magnetic field uniform region below the outside of the input module. Optionally, a closed loop signal conditioning circuit using ASIC is used, a feedback coil is integrated in the magnetic sensing unit, and a giant magnetoresistance (GMR) device is used for the magnetoresistance sensing component.

[0078] In addition, a third magnetic induction module is added, and the push-pull half-bridge output of the second magnetic sensing unit 312 and the push-pull full-bridge output of the third magnetic sensing unit 411 are selected for differentiation, thereby providing three output options. Therefore, the current sensor can achieve high-precision detection when high or low current is input, can effectively solve the problem that the magnetoresistance sensing component is easily saturated, is suitable for magnetic sensing units in various linear operating ranges, provides good resistance ability to external magnetic field interference, has the characteristics of being able to measure large direct current and alternating current, and has the characteristics of electrically isolated input and output. Combined with the characteristics of the GMR device such as small size, large signal amplitude, high sensitivity, low noise, and easy integration with semiconductor circuits, the design of the back-end signal processing circuit of the current sensor can be further simplified, the size of the entire current sensor can be reduced, and the cost of the current sensor can be reduced.

[0079] 9 shows a schematic diagram of yet another current sensor provided in an embodiment of the present invention. As shown in FIG. 9, the current sensor includes an input module, a high current detection module 3, a low current detection module 4, a circuit board 5, and a mechanical support housing 7. The input module consists of a differential copper bar 1 with a rectangular cross section, and two current shunt copper bars 21 and 22 with rectangular cross sections, which are connected in parallel and shunted, and the principle of generating a magnetic field is approximately the same as that of generating a magnetic field in FIG. 1.

[0080] The structure and principle of the high current detection module 3 are approximately the same as those of the high current detection module 3 in FIG. 1. The first magnetic sensing unit 311 and the second magnetic sensing unit 312 in the first magnetic induction module electrically form a differential half-bridge structure shown in FIG. 5, where differentiation is performed to form a differential voltage signal. The first signal output module is composed of a closed-loop signal conditioning circuit and a feedback coil 32. Optionally, the feedback coil 32 is integrated in the circuit board 5. The magnetoresistance unit is composed of magnetoresistance sensing components connected in series and parallel. Optionally, a CMR device is used for the magnetoresistance sensing component.

[0081] The third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 in the second magnetic induction module in the low current detection module 4 use two push-pull full bridge structures shown in FIG. 8 to perform differentiation and form a differential voltage signal to be output. Optionally, the fourth magnetic sensing unit 412 is located on the outer side of the input module, and the sensitivity directions of the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 are both to the right. In addition, in this embodiment, the second signal output module uses an open-loop signal conditioning circuit to perform conditioning amplification, temperature compensation, and linearity correction on the differential voltage signals of the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412. The open-loop signal conditioning circuit uses a PCB-level discrete component circuit, and the magnetoresistance sensing component uses a CMR device.

[0082] In this embodiment, the current sensor can achieve high-precision detection when high or low current is input, can effectively solve the problem of the magnetoresistance sensing component being easily saturated, is suitable for magnetic sensing units in different operating ranges, provides good resistance ability to external magnetic field interference, has the characteristics of being relatively small in size, capable of measuring large direct and alternating current, and has the characteristics of electrically isolated input and output.

[0083] An embodiment of the present invention further provides a current sensor different from the current sensor in the above embodiment, in which the differential copper bar may not be provided. The current sensor includes an input module, a high current detection module, a low current detection module, and a circuit board. The input module includes two or more current shunt copper bars connected in parallel. A current to be measured flows perpendicular to the cross section of the current shunt copper bars to generate a magnetic field at the position of the high current detection module and the low current detection module. The high current detection module is located in an internal gap of the input module. The high current detection module includes a first magnetic induction module and a first signal output module fixed on the circuit board, the first magnetic induction module includes a first magnetic sensing unit. The first magnetic sensing unit senses the magnetic field of the input module and forms an output signal of the current sensor through the first signal output module. The low current detection module is located outside the input module. The low current detection module includes a second magnetic induction module and a second signal output module fixed on the circuit board, the second magnetic induction module includes a second magnetic sensing unit. The second magnetic sensing unit senses the magnetic field of the input module and forms an output signal of the current sensor through the second signal output module.

[0084] 10 shows a schematic diagram of yet another current sensor provided in an embodiment of the present invention. As shown in FIG. 10, the current sensor includes an input module, a high current detection module 92, a low current detection module 93, a circuit board 94, and a mechanical support housing 96.

[0085] In this embodiment, the input module consists of two copper current shunt bars 911 and 912 with rectangular cross section, which are connected in parallel and shunted. The current to be measured flows perpendicular to the cross section of the copper current shunt bars 911 and 912, and the current to be measured is perpendicular to the plane of the paper and inward, generating a magnetic field at the location of the high current detection module 92 and the low current detection module 93.

[0086] The high current detection module 92 is located in the gap between the current shunt copper bar 911 and the current shunt copper bar 912, and includes a first magnetic induction module and a first signal output module fixed on the circuit board 94. The first magnetic induction module includes a magnetic sensing unit 921. The magnetic sensing unit 921 senses the magnetic field generated by the current in the input module, and forms an output signal of the current sensor through the first signal output module. In the high current detection module 92, the magnetic field generated in the magnetic sensing unit 921 by the current shunt copper bar 911 is to the right, and the magnetic field generated in the magnetic sensing unit 921 by the current shunt copper bar 912 is to the left, and the two cancel or subtract each other. By adjusting the shape of the current shunt copper bar, the magnitude of the magnetic field can be adjusted, thereby achieving high current detection.

[0087] The low current detection module 93 is located above the current shunt copper bar 912 and includes a second magnetic induction module and a second signal output module fixed on a circuit board 94. The second magnetic induction module includes a magnetic sensing unit 931. The magnetic sensing unit 931 senses the magnetic field generated by the current in the input module and forms an output signal of the current sensor through the second signal output module. Both the magnetic sensing unit 921 and the magnetic sensing unit 931 use a GMI device with a right-direction sensitivity direction. In the low current detection module 93, the magnetic sensing unit 931 is mainly affected by the right-direction magnetic field generated by the current shunt copper bar 912. The magnetic fields generated by the current shunt copper bars 911 and 912 have the same direction and are superimposed and increased, thereby generating a larger magnetic field in the case of low current, and thus achieving a relatively high accuracy in low current detection.

[0088] 10, optionally, the current sensor further includes a differential detection module 95. The differential detection module 95 uses the first magnetic sensing unit 921 in the high current detection module 92 and the second magnetic sensing unit 931 in the low current detection module 93 to differentially sense the magnetic field of the input module, and form the output signal of the current sensor through the third signal output module. Because there is a difference between the magnetic field at the position of the magnetic sensing unit 921 and the magnetic field at the position of the magnetic sensing unit 931, the output voltages of the two GMI devices can be differentiated, and the output signal of the current sensor can be formed through the third signal output module.

[0089] In this embodiment, the magnetic induction module senses the differential mode magnetic field generated by the measured current flowing through the input module in a non-differential manner. The high current detection module is located in the gap between the current shunt copper bar 911 and the current shunt copper bar 912 and measures the magnetic field after the current shunt copper bars 911 and 912 are cancelled. The high current measurement is achieved by the mutual cancellation of the current shunt copper bars. The low current detection module 93 is located above the current shunt copper bar 912 and measures the increased magnetic field after the current shunt copper bars 911 and 912 are overlapped. The high current detection module 3 and the low current detection module 4 each use a separate GMI device to measure the output signal in a non-differential manner, and the differential detection module 95 differentiates the voltages output by the two GMI devices, thereby providing three output options. This current sensor can measure large DC and AC current, realizes electrical isolation between input and output, is suitable for magnetic sensing units in various linear operating ranges, and has a simple structure, which further reduces the size and reduces the cost. In addition, it can use closed-loop negative feedback to enable high-precision current measurement with high linearity, strong resistance to common-mode interference, good temperature characteristics, and stable and reliable performance.

[0090] Please note that the above is merely a description of the preferred embodiments of the present invention and the technical principles used. Those skilled in the art should understand that the present invention is not limited to the specific embodiments in this specification, and those skilled in the art can make various obvious modifications, rearrangements, mutual combinations and substitutions without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail using the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is defined by the appended claims.

Claims

1. A current sensor comprising an input module, a high current detection module, a low current detection module, and a circuit board, The input module includes a differential copper bar and a current shunt copper bar connected in parallel, and a current to be measured flows perpendicular to a cross section of the differential copper bar and the current shunt copper bar to generate a magnetic field at the position of the high current detection module and the low current detection module; The high current detection module includes a first magnetic induction module and a first signal output module, the first magnetic induction module is fixed on the circuit board and disposed in an internal gap of the input module, the first magnetic induction module includes at least a first magnetic sensing unit and a second magnetic sensing unit therein, the first magnetic sensing unit and the second magnetic sensing unit differentially sense the magnetic field of the input module to form an output signal through the first signal output module; The low current detection module includes a second magnetic induction module and a second signal output module, the second magnetic induction module is fixed on the circuit board and disposed outside the input module, the second magnetic induction module includes at least a third magnetic sensing unit and a fourth magnetic sensing unit therein, the third magnetic sensing unit and the fourth magnetic sensing unit differentially sense the magnetic field of the input module and form an output signal through the second signal output module; Current sensor.

2. a switching module for selecting whether to switch to the high current detection module or the low current detection module according to a range of the measured current; the input module, the high current detection module, the low current detection module, and the switching module are electrically isolated from each other; The current sensor according to claim 1 .

3. the first magnetic sensing unit is located above the differential copper bar, and the sensitivity direction of the first magnetic sensing unit is the same as or opposite to the direction of the magnetic field generated in the first magnetic sensing unit by the differential copper bar, along a direction in the plane of the first magnetic induction module, and perpendicular to the direction of the measured current; The sensitivity direction of the second magnetic sensing unit is the same as the sensitivity direction of the first magnetic sensing unit, and the distance between the second magnetic sensing unit and the differential copper bar is greater than the distance between the first magnetic sensing unit and the differential copper bar; The current sensor according to claim 2 .

4. the differential copper bar is in a stepped shape near the first magnetic induction module and includes at least a first step and a second step; the first magnetic sensing unit is located above the first stage, and the second magnetic sensing unit is located above the second stage; The sensitivity direction of the first magnetic sensing unit is the same as or opposite to the direction of the magnetic field generated in the first magnetic sensing unit by the differential copper bar, is along a direction in the plane of the first magnetic induction module, and is perpendicular to the direction of the measured current; the sensitivity direction of the second magnetic sensing unit is the same as or opposite to the direction of the magnetic field generated in the second magnetic sensing unit by the differential copper bar, is along a direction in the plane of the second magnetic induction module, and is perpendicular to the direction of the measured current; The current sensor according to claim 1 or 3.

5. The first magnetic sensing unit and the second magnetic sensing unit in the first magnetic induction module are connected to form one of a differential half-bridge structure, a differential full-bridge structure, a double push-pull half-bridge differential structure, and a double push-pull full-bridge differential structure; the third magnetic sensing unit and the fourth magnetic sensing unit in the second magnetic induction module are connected to form one of a differential half-bridge structure, a differential full-bridge structure, a double push-pull half-bridge differential structure, and a double push-pull full-bridge differential structure; In the differential half-bridge structure, each magnetic sensing unit has one magnetoresistance bridge arm, and two magnetoresistance bridge arms in the same magnetic induction module are electrically differentiated together to form the differential half-bridge structure; In the differential full-bridge structure, each magnetic sensing unit has two magnetoresistance bridge arms, and the two magnetoresistance bridge arms in the same magnetic sensing unit are located on two opposite bridge arms, and the two magnetoresistance bridge arms of different magnetic sensing units are located on two adjacent bridge arms to form the differential full-bridge structure, and the output signal of the magnetic induction module is a differential signal of the differential full-bridge structure; In the double push-pull half-bridge differential structure, two magnetic sensing units in a same magnetic induction module both have two magnetic resistance bridge arms, the two magnetic resistance bridge arms in each magnetic sensing unit have opposite sensitivity directions, the two magnetic resistance bridge arms in the magnetic sensing units are upper and lower bridge arms, forming a push-pull half-bridge structure, the sensitivity directions of the upper bridge arms in the two magnetic sensing units are the same, and the sensitivity directions of the lower bridge arms in the two magnetic sensing units are the same, the two magnetic sensing units in a same magnetic induction module collectively form the double push-pull half-bridge differential structure, and the output signal of the magnetic induction module is a differential signal of the double push-pull half-bridge differential structure; In the double push-pull full-bridge differential structure, the two magnetic sensing units in the same magnetic induction module each have four magnetic resistance bridge arms, the four magnetic resistance bridge arms of the magnetic sensing units form a push-pull full-bridge structure, the sensitivity directions of the two magnetic sensing units in the same magnetic induction module are the same, the two magnetic sensing units in the same magnetic induction module collectively form the double push-pull full-bridge differential structure, and the output signal of the magnetic induction module is a differential signal of the double push-pull full-bridge differential structure; the magnetoresistive bridge arm being formed by connecting one or more magnetoresistive sensing components in series and in parallel; The current sensor according to claim 1 .

6. the first signal output module and the second signal output module each include an open-loop signal conditioning circuit using an open-loop circuit or a closed-loop signal conditioning circuit using a closed-loop circuit and a feedback coil; In the open-loop circuit, the first signal output module or the second signal output module uses the open-loop signal conditioning circuit to perform conditioning amplification, temperature compensation, and linearity correction on the differential signals of the two magnetic sensing units in the module, and the open-loop signal conditioning circuit is one of a printed circuit board (PCB) level discrete component circuit or an application specific integrated circuit (ASIC); In the closed loop circuit, the first signal output module or the second signal output module uses the closed loop signal conditioning circuit and the feedback coil to perform conditioning amplification, temperature compensation and linearity correction on the differential signals of the two magnetic sensing units in the module; the closed loop signal conditioning circuit, the feedback coil and the magnetic sensing unit in the high current detection module or the low current detection module form a closed loop magnetic field feedback; the differential signals of the two magnetic sensing units in the module are amplified; then a feedback magnetic field is generated through the feedback coil to cancel the differential mode magnetic field in an opposite direction; when the dynamic balance of the magnetic field is reached, the two magnetic sensing units in the module operate at an equal common mode magnetic field operating point; the feedback current of the feedback coil is sampled through a sampling resistor to form an output signal of the magnetic induction module; the closed loop signal conditioning circuit is one of a PCB level discrete component circuit or an ASIC, and the feedback coil is integrated within the closed loop signal conditioning circuit, the circuit board, the magnetic sensing unit, the ASIC, or the magnetic induction module; The current sensor according to claim 1 .

7. The third magnetic sensing unit and the fourth magnetic sensing unit in the second magnetic induction module are detected by the following two methods: (1) The third magnetic sensing unit is located above the input module, and the fourth magnetic sensing unit is located below or to the side of the input module, and the sensitivity directions of the third magnetic sensing unit and the fourth magnetic sensing unit are the same. (2) The third magnetic sensing unit and the fourth magnetic sensing unit are located on the same side with respect to the input module, the third magnetic sensing unit is located within a vertical projection coverage range of the current shunt copper bar or the differential copper bar closest to the third magnetic sensing unit, the sensitivity direction of the third magnetic sensing unit is the same as or opposite to the direction of the magnetic field generated at the position of the third magnetic sensing unit by the current shunt copper bar or the differential copper bar closest to the third magnetic sensing unit, is along a direction in the plane of the second magnetic induction module and is perpendicular to the direction of the measured current, and the fourth magnetic sensing unit is located outside the vertical projection coverage range of the current shunt copper bar and the differential copper bar, and the sensitivity direction of the fourth magnetic sensing unit is the same as the sensitivity direction of the third magnetic sensing unit. The current sensor of claim 1 , wherein the current sensor is disposed in any one of the following positions:

8. Further comprising a third current detection module, the third current detection module comprising a third magnetic induction module and a third signal output module; the third magnetic induction module is composed of the first magnetic sensing unit or the second magnetic sensing unit in the first magnetic induction module, and the third magnetic sensing unit or the fourth magnetic sensing unit in the second magnetic induction module, and the two magnetic sensing units in the third magnetic induction module differentially sense the magnetic field of the input module, and form an output signal of the current sensor through the third signal output module; The current sensor according to claim 1 .

9. 2. The current sensor of claim 1, wherein the number of current shunt copper bars is one or more, any current shunt copper bar is located above the first magnetic induction module or below the differential copper bar, and the vertical projection range of any current shunt copper bar covers the first magnetic sensing unit and the second magnetic sensing unit in the first magnetic induction module.

10. A current sensor comprising an input module, a high current detection module, a low current detection module, and a circuit board, The input module includes two or more copper bars for current shunting connected in parallel, and a current to be measured flows perpendicular to a cross section of the copper bars for current shunting to generate a magnetic field at the position of the high current detection module and the low current detection module; The high current detection module is located in the internal gap of the input module, and the high current detection module includes a first magnetic induction module and a first signal output module fixed on the circuit board, the first magnetic induction module includes a first magnetic sensing unit, and the first magnetic sensing unit senses the magnetic field of the input module and forms an output signal of the current sensor through the first signal output module; The low current detection module is located outside the input module, and the low current detection module includes a second magnetic induction module and a second signal output module fixed on the circuit board, the second magnetic induction module includes a second magnetic sensing unit, and the second magnetic sensing unit senses the magnetic field of the input module and forms an output signal of the current sensor through the second signal output module; Current sensor.

11. 11. The current sensor of claim 10, further comprising a differential detection module, wherein the differential detection module differentially senses the magnetic field of the input module using the first magnetic sensing unit in the high current detection module and the second magnetic sensing unit in the low current detection module to form an output signal of the current sensor through a third signal output module.

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