Current Sensor

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 INVENTION Embodiments of the present invention relate to the technical field of current detection 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 information in other forms that are 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] Currently, 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] Shunts are based on the principle that when direct current passes through a standard resistor, a voltage is generated across the resistor, making them suitable for low frequencies and low power. Shunts have the following disadvantages: they lack electrical isolation between the signal output terminal and the current loop under test, can only measure a single type of object, and are difficult to use with shunts to measure large alternating currents. Current transformers are based on the principle of electromagnetic induction and can only measure alternating currents. Rogowski coils are suitable for measuring alternating currents over a relatively wide frequency range, but cannot measure direct currents. Rogowski coils have relatively low sensitivity and are relatively large. Fiber optic current sensors are based on the Faraday effect of magneto-optical crystals. Fiber optic current sensors use optical fiber as the sensing component, which is sensitive to and capable of detecting external information. They have relatively high measurement accuracy and are easy to miniaturize, but require special optical fiber, which is expensive. There are many types of magnetic current sensors. For example, Hall current sensors have the advantages of mature technology, low cost, high integration, and small size, but they have low sensitivity, poor temperature drift characteristics, and narrow bandwidth, making it difficult to use them for high-precision current measurement. Compared with Hall current sensors, other types of magnetoresistive 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 a 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 comprises 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 comprises 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 comprises 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 shunts connected in parallel, and the current to be measured flows perpendicular to the cross section of these copper bars for current shunts to generate a magnetic field at the positions of the high current detection module and the low current detection module; a high-current detection module located in the internal gap of the input module, the high-current detection module including a first magnetic induction module fixed on a circuit board and a first signal output module, the first magnetic induction module including a first magnetic sensing unit, the first magnetic sensing unit sensing the magnetic field of the input module and forming 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 fixed on a circuit board and a second signal output module, 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; 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 through which the measured current is shunted. The high-current detection module is located within the internal gap of the input module, and the low-current detection module is located outside the input module. The first and second magnetic induction modules differentially sense the magnetic field of the input module and then form an output signal through the first and second signal output modules, respectively, thereby realizing the current sensor differentially senses the differential-mode magnetic field generated by the measured current flowing through the input module through the magnetic induction modules. In the current sensor provided in this embodiment of the present invention, the current input range and sensitivity can be adjusted by adjusting the shape and distribution of each copper bar, thereby increasing the current measurement range and making the current sensor suitable for magnetic sensing units in various operating ranges. This current sensor can achieve high-precision detection when high or low current is input, and can also measure direct current and / or alternating current. Furthermore, the input module and the signal output module are electrically isolated, thereby improving resistance 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 required 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 undoubtedly fall within the scope of the claims of the present invention. [Brief explanation of the drawings]

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

[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 implementation forms with reference to the drawings in the embodiments of the present invention. It is clear that the embodiments described here are only some embodiments rather than 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 will fall within the protection scope of the present invention.

[0012] 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. A current to be measured flows perpendicular to the cross sections of the differential copper bar 1 and the current shunt copper bar 2, generating a magnetic field at the positions 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 within 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. The first magnetic sensing unit 311 and the second magnetic sensing unit 312 differentially sense the magnetic field of the input module and generate 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, the second magnetic induction module is fixed on the circuit board 5 and arranged outside the input module, the second magnetic induction module includes at least a third magnetic sensing unit 411 and a fourth magnetic sensing unit 412 therein, 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, and in this case, the gap is the internal gap of the input module. Accordingly, 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 disposed within 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 disposed 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 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 current to be measured 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, 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 current to be measured 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 current to be measured. 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, is along a direction in the plane of the first magnetic induction module, and is 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, is along a direction in the plane of the second magnetic induction module, and is 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, with 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 section includes a first section 11 and a second section 12, as shown in Fig. 1. The first magnetic sensing unit 311 is located in the uniform magnetic field region above the first section 11, and the second magnetic sensing unit 312 is located in the uniform magnetic field region above the second section 12. Both the first magnetic sensing unit 311 and the second magnetic sensing unit 312 are located in the uniform magnetic field region of the current shunt copper bar 2, and their sensitivity directions are both rightward.

[0020] Figure 2 shows the magnetic field simulation diagram of the stepped differential copper bar. in Assume that the current is 50 A and the cross-sectional width of the stepped differential copper bar 1 is 10 mm. When the current to be measured flows into the input module, a magnetic field is generated in the horizontal plane 0.6 mm above the differential copper bar 1. As shown in Figure 2, near the step-rising section of the differential copper bar 1, there is an obvious difference in the magnetic field 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, a 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 entire curve shows an obvious downward shift, that is, the magnetic field is reduced.

[0022] Measured current I in The current flowing through the first stage 11 is defined as I 11, the current passing through the second stage 12 is I 12 Assuming 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 Equation (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 sections according to the height of the second stage 12. The height of the lower rectangle divided by the differential copper bar 1 is the same as 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 the same as the first stage 11. In this 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 considered to be the forward direction of the magnetic field, then according to Biot-Savart's law for a 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 Each of these varies 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 equation, k1 is the linear constant of the uniform magnetic field generated at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 by the current I'1 in the lower rectangle, k3 is the linear constant of the uniform magnetic field generated at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 by the current I2 in the current shunt copper bar, 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 in 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 fields at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 are converted into the 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 the common-mode magnetic field H CM and the differential mode magnetic field H DM can be converted into a superposition representation of H 211 =H CM +H DM (6) H 212 =H CM -H DM

[0028] 1, it can be seen that the direction of the magnetic field generated at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 by the current I'1 in the lower rectangle is opposite to the direction of the magnetic field generated at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 by the current I2 in the current shunt copper bar, and the two can cancel each other out. Specifically, the magnetic field generated at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 by the current I'1 in the lower rectangle is k1I'1, and the magnetic field generated at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit 312 by the current I2 in the current shunt copper bar is K3I2, and the two can decrease or reduce, 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 differential copper bar 1 alone can be in the same direction, zero, or opposite directions. The magnetic field generated by the differential copper bar 1 alone can be understood to be the magnetic field generated at the positions 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 at the positions of the first magnetic sensing unit 311 and the second magnetic sensing unit. CM 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, according to Biot-Savart's law for magnetic fields generated by current-carrying conductors, 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, 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., at an upper position outside the input module. In other embodiments, the low-current detection module can also be optionally located on the side of the differential copper bar away from the current shunt copper bar, i.e., at a lower position outside the input module. Therefore, 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] 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 increased, thereby generating a larger magnetic field in the case of low current, ensuring more accurate detection of the low current to be measured, and extending the input range of the current that can be measured by the current sensor.

[0032] Optionally, the number of 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 current shunt copper bars 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 one embodiment of the present invention. As shown in FIG. 4, optionally, a differential copper bar 1 is located inside the circuit board 5. Optionally, the number of current shunt copper bars is two, where a current shunt copper bar 21 is located below the differential copper bar 1, and a current shunt copper bar 22 is located above the first magnetic induction module, and the vertical projection ranges of the current shunt copper bars 21 and 22 cover 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 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 uniform magnetic field region of the current shunt copper bar 21 and the uniform magnetic field region of the current shunt copper bar 22, and their sensitivity directions are both rightward. The first magnetic sensing unit 311 is located in the uniform magnetic field region of the differential copper bar 1. In this 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 shunt 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 rectangular bar in FIG. 1, and the current of the current shunt copper bar 21 in FIG. 4 can be compared to the current I'1 of the lower rectangular bar 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 region 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 calculated as the measured current I in The measured current is directly proportional to the differential mode magnetic field H DM The analysis and calculation of copper bars for multiple current shunts involves 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 completely cancel each other 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, and therefore 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 canceled out, i.e., the measured current is 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 described above, the high current detection module 3 uses differential measurement of the differential mode magnetic field generated by the input module, and partially or completely cancels out the common mode magnetic field, thereby effectively solving the problem of magnetoresistive sensing components becoming easily saturated, while also adjusting and extending the current measurement range and providing good resistance to external magnetic field interference. As a result, this current sensor is suitable for current detection in a variety of 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 current to be measured. 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 through which the measured current is shunted. The high-current detection module is located within the internal gap of the input module, and the low-current detection module is located outside the input module. The first and second magnetic induction modules differentially sense the magnetic field of the input module and then form an output signal through the first and second signal output modules, respectively, thereby realizing the current sensor differentially senses the differential-mode magnetic field generated by the measured current flowing through the input module through the magnetic induction modules. In the current sensor provided in this embodiment of the present invention, the current input range and sensitivity can be adjusted by adjusting the shape and distribution of each copper bar, thereby increasing the current measurement range and making the current sensor suitable for magnetic sensing units in various operating ranges. This current sensor can achieve high-precision detection when high or low current is input, and can also measure direct current and / or alternating current. Furthermore, the input module and the signal output module are electrically isolated, thereby improving resistance 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 magnetoresistive bridge arm, and two magnetoresistive 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 magnetoresistive bridge arms, and the two magnetoresistive bridge arms in the same magnetic sensing unit are located on two opposite bridge arms, and the two magnetoresistive 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 magnetoresistive bridge arms, the two magnetoresistive bridge arms in each magnetic sensing unit have opposite sensitivity directions, the two magnetoresistive bridge arms in the magnetic sensing unit 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 as a whole 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 each contain four magnetoresistive bridge arms, the four magnetoresistive bridge arms of the magnetic sensing units form a push-pull full-bridge structure, the two magnetic sensing units in the same magnetic induction module have the same sensitivity direction, and the two magnetic sensing units in the same magnetic induction module as a whole form a 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 arms are formed by connecting one or more magnetoresistive sensing components in series and 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 magnetoelectric coupling device (ME); and (2) the magnetoresistive sensing component forming the differential structure in the two magnetic sensing units is comprised of one of an anisotropic magnetoresistive (AMR) device, a giant magnetoresistive (GMR) device, a tunneling magnetoresistive (TMR) device, and a colossal magnetoresistive (CMR) device.

[0051] FIG. 5 shows a schematic diagram of a differential half-bridge structure. As shown in FIG. 5, the high current detection module 3 uses a single bridge with a differential half-bridge structure. 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, pointing horizontally to the right. Optionally, the magnetoresistive bridge arm comprises 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 Figure 5, in the case shown in Figure 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 by the differential copper bar 1 and the current shunt copper bar 2 is horizontally rightward. In other words, after the cancellation, the common mode magnetic field and the magnetic field generated by the differential copper bar 1 at the position of the first magnetic induction module 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 greater than the rightward magnetic field at the position of the second magnetic sensing unit 312. In FIG. 5, because the sensitivity directions of the two magnetoresistive bridge arms 311a and 312a are both rightward, the rightward magnetic field at the position of the magnetoresistive bridge arm 311a is greater than the magnetic field at the position of the magnetoresistive bridge arm 312a. As a result, the resistance value of the magnetoresistive bridge arm 311a becomes less than the resistance value of the magnetoresistive bridge arm 312a, thereby realizing the conversion from the magnetic field to a voltage. Therefore, Vout in FIG. 5 changes accordingly according to the situation of the current to be measured, forming a differential voltage signal.

[0054] FIG. 6 shows a schematic diagram of a differential full-bridge structure. As shown in FIG. 6, the low current detection module 4 uses a single bridge with a differential full-bridge structure. 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 magnetoresistive bridge arms 411a and 411b, and the fourth magnetic sensing unit 412 includes two magnetoresistive bridge arms 412a and 412b. The four magnetoresistive bridge arms 411a, 411b, 412a, and 412b in the second magnetic induction module have the same sensitivity direction, facing horizontally to the right, and are electrically connected to form the same differential full-bridge structure. Optionally, the magnetoresistive bridge arms are composed of one or more magnetoresistive sensing components, and the magnetoresistive sensing component in each magnetoresistive bridge arm is a TMR device.

[0055] 1 and 6, the rightward magnetic field in the third magnetic sensing unit 411 is greater 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 greater 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 less than the resistance values ​​of the magnetoresistive bridge arms 412a and 412b. Based on this, it can be concluded that in FIG. 6, voltage V2 is greater than 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 FIGS. 4 and 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 magnetoresistive bridge arms 311a1 and 311a2, which form a first push-pull half-bridge structure, with the sensitivity direction of the magnetoresistive bridge arm 311a1 facing left and the sensitivity direction of the magnetoresistive bridge arm 311a2 facing 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, and the magnetoresistive sensing components are GMR devices.

[0057] 1 and 7, assuming that the common-mode magnetic field is canceled out and directed to the right, and the differential-mode magnetic field is superimposed, the right-pointing magnetic field in the first magnetic sensing unit 311 is greater than the right-pointing magnetic field in the second magnetic sensing unit 312, the resistance of the magnetoresistive bridge arm 311a1 is greater than the resistance of the magnetoresistive bridge arm 311a2, the resistance of the magnetoresistive bridge arm 312a1 is greater than the resistance of the magnetoresistive bridge arm 312a2, and the resistance difference between the magnetoresistive bridge arms 311a1 and 311a2 is greater than the resistance difference between the magnetoresistive bridge arms 312a1 and 312a2, thereby realizing a magnetic field-to-voltage conversion. Based on this, V1a and V2a in FIG. 7 change accordingly according to the conditions of the current to be measured to form a differential voltage signal.

[0058] 8 shows a schematic diagram of a double push-pull full-bridge differential structure. Referring to FIGS. 4 and 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 magnetoresistive bridge arms 411b1, 411b2, 411b3, and 411b4 therein, forming a push-pull full-bridge structure, where the sensitive directions of the magnetoresistive bridge arms 411b2 and 411b3 are both leftward, and the sensitive directions of the magnetoresistive 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 sensitive directions of the magnetoresistive bridge arms 412b2 and 412b3 are both leftward and the sensitive 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 signals of the above two push-pull full-bridge structures change 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 either 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, which performs 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, in which 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 out the differential-mode magnetic fields in opposite directions. When the magnetic field reaches dynamic equilibrium, 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 a 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 into 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 a first signal output module using a closed-loop circuit within a 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 within 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 into the circuit board, or into the magnetic sensing unit, or by using an ASIC, or 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, a closed-loop signal conditioning circuit and a 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 dynamic equilibrium of the magnetic field is reached, 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, a PCB-level discrete component circuit is used for the closed-loop signal conditioning 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 into the first magnetic induction module. In this case, reference numeral 32 may be equivalent to the magnetic field feedback coil in the first signal output module. The plane on which the magnetic field feedback coil 32 is located is parallel to the plane on which the first magnetic sensing unit 311 and the second magnetic sensing unit 312 are located. The cross sections of the magnetic field feedback coil 32 are symmetrically distributed along both sides of the midline. The current direction on one side of the midline is outward, perpendicular to the plane of the paper, and the current direction on the other side of the midline is inward, perpendicular to the plane of the paper.

[0068] Regarding the direction of the feedback magnetic field generated by the magnetic field feedback coil 32, taking a 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 in the cross section of a 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 perpendicular to the plane of the page and points outward, and the current direction in the cross section of a 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 perpendicular to the plane of the page and points inward. 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, a magnetic field feedback coil 32 is integrated into the magnetic sensing unit in the module, and a magnetic field feedback coil 42 is integrated into the magnetic sensing unit in the module. The location of the feedback coils is not limited to the location shown in the above figure. Although the distribution or connection of the magnetic field feedback coils is slightly different, the principle of magnetic field feedback is the same, and both modules use the distribution of the magnetic field feedback coils 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 magnetic field feedback principle 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] This current sensor achieves high-precision detection even when a high or low current is input, effectively solves the problem of magnetoresistive sensing components easily becoming saturated, is suitable for magnetic sensing units with a wide range of linear operating ranges, provides good resistance to external magnetic field interference, can measure large DC and AC currents, and has electrically isolated input and output. Combined with the TMR device's small size, large signal amplitude, high sensitivity, low noise, and easy integration with semiconductor circuits, this further simplifies the design of the current sensor's back-end signal processing circuit, reduces the overall size of the current sensor, and lowers its cost.

[0072] Optionally, the third magnetic sensing unit and the fourth magnetic sensing unit in the second magnetic induction module are arranged in one of 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 third magnetic sensing unit and the fourth magnetic sensing unit have the same sensitivity direction; (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 location of the third magnetic sensing unit by the current shunt copper bar or differential copper bar closest to the third magnetic sensing unit, and is 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] 1 , the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 are located on the same side of the input module, 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 area of ​​the current shunt copper bar 2, and 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 in-plane direction of the second magnetic induction module and perpendicular to the direction of the current to be measured. The fourth magnetic sensing unit 412 is located outside the vertical projection coverage area 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 third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 have the same sensitivity direction, which is toward the right. Specifically, the third magnetic sensing unit 411 is located in a uniform magnetic field area above the outside of the input module, and the fourth magnetic sensing unit 412 is located in a uniform magnetic field area below the outside of the input module. The magnetic fields generated at the positions of the third magnetic sensing unit 411 and the fourth magnetic sensing unit 412 of the low current detection module 4 by the differential copper bar 1 and the current shunt copper bars 21 and 22 are superimposed and increased, thereby generating a larger magnetic field in the case of a low current and ensuring more accurate detection of the low current being measured.

[0075] Optionally, the current sensor further includes a third current detection module, the third current detection module including a third magnetic induction module and a third signal output module, the third magnetic induction module including 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, 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.

[0076] As shown in FIG. 4 , the current sensor optionally further includes a third current detection module 8, which 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 with 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 with 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 rectangular cross sections are connected in parallel to shunt the current to be measured. 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, while the low-current detection module 4 uses a double full-bridge structure with a push-pull full bridge for differentiation. Furthermore, a third magnetic sensing unit 411 is located above the input module in the uniform magnetic field region, and a fourth magnetic sensing unit 412 is located below the input module in the uniform magnetic field region. Optionally, an ASIC-based closed-loop signal conditioning circuit is used, a feedback coil is integrated into the magnetic sensing unit, and a giant magnetoresistance (GMR) device is used for the magnetoresistive 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, this current sensor can achieve high-precision detection when high or low currents are input, effectively solves the problem of magnetoresistive sensing components easily becoming saturated, is suitable for magnetic sensing units with various linear operating ranges, provides good resistance to external magnetic field interference, can measure large DC and AC currents, and has electrically isolated input and output. Combined with the GMR device's small size, large signal amplitude, high sensitivity, low noise, and easy integration with semiconductor circuits, this further simplifies the design of the current sensor's back-end signal processing circuit, reduces the overall size of the current sensor, and lowers its cost.

[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 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 consists of a closed-loop signal conditioning circuit and a feedback coil 32. Optionally, the feedback coil 32 is integrated into the circuit board 5. The magnetoresistive unit consists of magnetoresistive sensing components connected in series and in parallel. Optionally, a CMR device is used as the magnetoresistive 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 rightward. 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 magnetoresistive 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 magnetoresistive sensing components easily saturating, is suitable for magnetic sensing units in various operating ranges, provides good resistance to external magnetic field interference, has the characteristics of being relatively small in size, being able to measure large direct currents and alternating currents, and has the characteristics of electrically isolated input and output.

[0083] One embodiment of the present invention further provides a current sensor different from the current sensor in the above embodiment, which may not include a differential copper bar. 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, generating a magnetic field at the positions of the high current detection module and the low current detection module. The high current detection module is located within the 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, and 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, and 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 current shunt copper bars 911 and 912 with rectangular cross sections, which are connected in parallel and shunted. The current to be measured flows perpendicular to the cross sections of the current shunt copper bars 911 and 912, and the current to be measured is directed inward, perpendicular to the plane of the paper, generating a magnetic field at the positions 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 a 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 generates a current sensor output signal 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 points to the right, while the magnetic field generated in the magnetic sensing unit 921 by the current shunt copper bar 912 points to the left, canceling or subtracting each other. The magnitude of the magnetic field can be adjusted by adjusting the shape of the current shunt copper bar, 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 generates a current sensor output signal through the second signal output module. Both the magnetic sensing unit 921 and the magnetic sensing unit 931 use GMI devices with a rightward sensitivity direction. In the low current detection module 93, the magnetic sensing unit 931 is mainly affected by the rightward 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 enhanced, thereby generating a larger magnetic field in the case of low currents and thus achieving 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 a first magnetic sensing unit 921 in the high current detection module 92 and a second magnetic sensing unit 931 in the low current detection module 93 to differentially sense the magnetic field of the input module and form an output signal of the current sensor through a 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 an output signal of the current sensor can be formed through the third signal output module.

[0089] In this embodiment, the magnetic induction module non-differentially senses the differential-mode magnetic field generated by the measured current flowing through the input module. 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 canceled out. High-current measurement is achieved by the mutual cancellation of the multiple current shunt copper bars. The low-current detection module 93 is located above the current shunt copper bar 912 and measures the magnetic field that is increased 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 separate GMI devices to measure their output signals 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 currents, achieves electrical isolation between input and output, is suitable for magnetic sensing units with a wide range of linear operating ranges, and has a simple structure, which further reduces size and cost.In addition, it uses 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] It should be noted 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 herein, 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 comprises 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 comprises 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 comprises 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; A current sensor, wherein 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.

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 current to be measured; The current sensor of claim 1 , wherein the input module, the high current detection module, the low current detection module, and the switching module are electrically isolated from each other.

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, is along a direction in the plane of the first magnetic induction module, and is perpendicular to the direction of the current to be measured; 3. The current sensor of claim 2, wherein a sensitivity direction of the second magnetic sensing unit is the same as a sensitivity direction of the first magnetic sensing unit, and a distance between the second magnetic sensing unit and the differential copper bar is greater than a distance between the first magnetic sensing unit and the differential copper bar.

4. the differential copper bar is stepped 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 step, and the second magnetic sensing unit is located above the second step; 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 current to be measured; 4. The current sensor of claim 1, wherein 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 orthogonal to the direction of the current to be measured.

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 magnetoresistive bridge arm, and two magnetoresistive 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 magnetoresistive bridge arms, and two magnetoresistive bridge arms in the same magnetic sensing unit are located on two opposite bridge arms, and two magnetoresistive 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, the two magnetic sensing units in the same magnetic induction module both have two magnetoresistive bridge arms, the two magnetoresistive bridge arms in each magnetic sensing unit have opposite sensitivity directions, the two magnetoresistive 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 the 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; In the double push-pull full-bridge differential structure, each of the two magnetic sensing units in the same magnetic induction module has four magnetoresistive bridge arms, the four magnetoresistive 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, and the two magnetic sensing units in the same magnetic induction module form the 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 current sensor of claim 1 , wherein the magnetoresistive bridge arms are formed by connecting one or more magnetoresistive sensing components in series and parallel.

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 same magnetic induction 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 same magnetic induction 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 same magnetic induction module are amplified; and then a feedback magnetic field is generated through the feedback coil to cancel out the differential mode magnetic fields in opposite directions; when the magnetic field reaches dynamic equilibrium, the two magnetic sensing units in the same magnetic induction module operate at an equal common mode magnetic field operating point; and the feedback current of the feedback coil is sampled through a sampling resistor to form an output signal of the magnetic induction module; 2. The current sensor of claim 1, wherein 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.

7. The third magnetic sensing unit and the fourth magnetic sensing unit in the second magnetic induction module are connected 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 third magnetic sensing unit and the fourth magnetic sensing unit have the same sensitivity direction.

2. The current sensor of claim 1, wherein the third magnetic sensing unit and the fourth magnetic sensing unit are located on the same side of 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 a direction of a 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 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.

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; 2. The current sensor of claim 1, wherein the third magnetic induction module comprises 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 to form an output signal of the current sensor through the third signal output module.

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 comprises 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, 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; A current sensor, wherein the low current detection module is located outside the input module, and the low current detection module comprises a second magnetic induction module and a second signal output module fixed on the circuit board, the second magnetic induction module comprises 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.

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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