Current sensor

Abstract

The invention discloses a current sensor comprising a shunt used for measuring a first primary side current of the current sensor; and the magnetic field measurer is arranged on the shunt, a plurality of chips are arranged in the magnetic field measurer, the magnetic field measurer measures the second primary side current of the current sensor through the plurality of chips, and the first primary side current and the second primary side current are mutually referenced, so that the measurement safety and the measurement accuracy of the current sensor are ensured. According to the current sensor, the magnetic field measurer is integrated on the diverter, the current sensor based on the diverter and the magnetic field measurement chip annular array is formed, two current testing modes are combined into one, the product size is reduced, and meanwhile the requirement that two current measuring methods need to be adopted in specific occasions is met; and the universality of the current sensor is improved. And the first primary side current and the second primary side current measured by the shunt and the magnetic field measurer are backups for each other, so that the functional safety of the product is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of current signal measurement, and more specifically, to a current sensor. Background Art

[0002] Existing current sensors usually use a single shunt to measure the primary current, which can only meet the measurement requirements of a specific occasion and have poor versatility. In addition, the primary current measured by the existing current sensor has no reference. When the shunt measurement is inaccurate, the measurement accuracy of the current sensor is affected, and the safety is poor. Summary of the invention

[0003] An object of the present invention is to provide a new technical solution for a current sensor, which can at least solve the problems of poor versatility and inability to ensure measurement accuracy and safety of current sensors in the prior art.

[0004] According to a first aspect of the present invention, a current sensor is provided, comprising: a shunt, the shunt being used to measure a first primary current of the current sensor; and a magnetic field measuring device, the magnetic field measuring device being arranged on the shunt, the magnetic field measuring device being provided with a plurality of chips, the magnetic field measuring device measuring a second primary current of the current sensor through the plurality of chips, the first primary current and the second primary current being referenced to each other to ensure the measurement safety and accuracy of the current sensor.

[0005] Optionally, the shunt includes a first region, a second region and a third region, the second region is located between the first region and the third region, and the magnetic field meter is disposed on the second region.

[0006] Optionally, a circuit board is provided on the second area of ​​the diverter, and a thermistor is welded on the circuit board.

[0007] Optionally, the first region and the third region of the diverter are respectively made of red copper material, and the second region is made of manganese copper material.

[0008] Optionally, a calculation formula for obtaining the first primary current of the current sensor is:

[0009] I=V SHUNT / r t ;

[0010] Among them, V SHUNT is the voltage across the shunt, r t is the resistance of the shunt at the current temperature;

[0011] And get r t The calculation formula is:

[0012] rt =R0*(1+R COMP / 10 6 );

[0013] Wherein, R0 is the resistance of the shunt at 25°C; R COMP is the resistance of the shunt at a specific temperature.

[0014] Optionally, the resistance R of the shunt at a specific temperature COMP The calculation formula is:

[0015] R COMP =A*T 2 +B*T+C;

[0016] Wherein, T is temperature, A, B and C are coefficients of the calculation formula, respectively, and the coefficients are obtained according to calibration.

[0017] Optionally, the magnetic field measurer is an annular column, and the plurality of chips are spaced apart and evenly distributed along the annular magnetic field measurer.

[0018] Optionally, the chip includes: a first chip, a second chip and a third chip, the first chip, the second chip and the third chip are spaced and evenly distributed along the circumference of the magnetic field measuring device, the distances between the first chip, the second chip and the third chip and the center of the magnetic field measuring device are R1, R2 and R3 respectively, wherein the magnetic induction intensities measured by the first chip, the second chip and the third chip are B1, B2 and B3 respectively, so as to obtain the average magnetic induction intensity B of the magnetic field measuring device. OUT .

[0019] Optionally, the calculation formulas for the magnetic induction intensities measured by the first chip, the second chip and the third chip are respectively:

[0020]

[0021] The average magnetic induction intensity B of the magnetic field measuring device OUT The calculation formula is:

[0022]

[0023] Wherein, B1, B2 and B3 are the magnetic induction intensities measured by the first chip, the second chip and the third chip respectively, and B OUT is the average magnetic induction intensity of the magnetic field meter, I is the second primary current of the current sensor, R1, R2 and R3 are the distances between the first chip, the second chip and the third chip and the center of the magnetic field meter respectively, and μ0 is the calculation coefficient of the magnetic induction intensity.

[0024] Optionally, the calculation formula of the second primary current is:

[0025]

[0026] Among them, B OUT is the average magnetic induction intensity of the magnetic field measuring device.

[0027] The current sensor of the present invention integrates a magnetic field measuring device on a shunt to form a current sensor based on a ring array of shunt and magnetic field measuring chips, combines two current testing methods into one, reduces the product volume, and solves the need to use two current measurement methods in specific occasions, thereby improving the versatility of the current sensor. In addition, the first primary current and the second primary current measured by the shunt and the magnetic field measuring device serve as backup for each other, thereby achieving functional safety of the product.

[0028] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0030] Figure 1 is a schematic structural diagram of a current sensor according to an embodiment of the present invention;

[0031] Figure 2 is a structural schematic diagram of a shunt of a current sensor according to an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of a circular array of magnetic field measuring devices of a current sensor according to an embodiment of the present invention.

[0033] Reference numerals:

[0034] Diverter 10; first area 11; second area 12; third area 13; mounting hole 14;

[0035] Magnetic field measuring device 20. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0037] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0038] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0039] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0040] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0041] In the specification and claims of the present invention, if the term "first" or "second" is involved, it may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0042] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" involved should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] The current sensor according to the embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0045] like Figure 1As shown, the current sensor according to the embodiment of the present invention includes a shunt 10 and a magnetic field measurer 20 .

[0046] Specifically, the shunt 10 is used to measure the first primary current of the current sensor. The magnetic field measurer 20 is arranged on the shunt 10, and a plurality of chips are arranged in the magnetic field measurer 20. The magnetic field measurer 20 measures the second primary current of the current sensor through the plurality of chips. The first primary current and the second primary current are referenced to each other to ensure the measurement safety and measurement accuracy of the current sensor.

[0047] In other words, see Figure 1 The current sensor according to the embodiment of the present invention is mainly composed of a shunt 10 and a magnetic field measuring device 20, wherein the shunt 10 is used to measure the first primary current of the current sensor. Figure 1 As shown, the magnetic field meter 20 is installed on the shunt 10, and the shunt 10 and the magnetic field meter 20 are combined into one. One path of the current sensor is output to the shunt 10, and the other path is output to the magnetic field meter 20. The output of the shunt 10 is independently provided to the user, forming a current sensor based on the shunt 10 and the ring array of magnetic field measurement chips, reducing the product volume, while solving the need to use two current measurement methods in specific occasions, and improving the versatility of the current sensor. A plurality of chips are arranged in the magnetic field meter 20, and the magnetic field meter 20 can measure the second primary current of the current sensor through the plurality of chips. Among them, the first primary current and the second primary current are referenced to each other to form a backup. The shunt 10 serves as the primary conductor of the current sensor of the ring array of magnetic field measurement chips, and its relative position with the magnetic field measurement chip is fixed, which improves the measurement accuracy of the current sensor of the ring array of magnetic field measurement chips and ensures the measurement safety and accuracy of the current sensor.

[0048] Therefore, according to the current sensor of the embodiment of the present invention, the magnetic field measuring device 20 is integrated on the shunt 10 to form a current sensor based on the shunt 10 and the ring array of magnetic field measuring chips, combining two current testing methods into one, reducing the product volume, and solving the need to use two current measurement methods in specific occasions, thereby improving the versatility of the current sensor. In addition, the first primary current and the second primary current measured by the shunt 10 and the magnetic field measuring device 20 are backed up for each other to achieve functional safety of the product.

[0049] According to an embodiment of the present invention, the shunt 10 includes a first region 11 , a second region 12 and a third region 13 , the second region 12 is located between the first region 11 and the third region 13 , and the magnetic field measurer 20 is disposed on the second region 12 .

[0050] That is to say, Figure 2As shown, the shunt 10 is mainly composed of three parts: a first area 11, a second area 12 and a third area 13, wherein the second area 12 is located between the first area 11 and the third area 13, and the magnetic field meter 20 is installed on the second area 12, so as to ensure that the relative position of the magnetic field measurement chip is fixed, thereby improving the measurement accuracy of the current sensor of the ring array of the magnetic field measurement chip and ensuring the measurement safety and accuracy of the current sensor.

[0051] According to one embodiment of the present invention, a circuit board is provided on the second region 12 of the shunt 10, and a thermistor is welded on the circuit board. In other words, in order to facilitate application and improve the accuracy of the shunt 10 after calibration, a circuit board (not shown in the figure) can be welded on the second region 12 of the shunt 10, a terminal is provided on the circuit board, and a thermistor (generally a negative temperature coefficient thermistor, NTC) is welded on the circuit board. The current temperature T of the shunt 10 can be calculated based on the value of the thermistor, and then the resistance value Rt of the shunt 10 can be calculated based on the temperature T. The first primary current value I=V 分流器10 / R t .

[0052] According to an embodiment of the present invention, the first region 11 and the third region 13 of the diverter 10 are respectively made of red copper material, and the second region 12 is made of manganese copper material.

[0053] That is to say, Figure 2 As shown, the first area 11 and the third area 13 of the shunt 10 are made of copper material, and the second area 12 can be made of manganese copper material. The two ends of the shunt 10 are made of copper and have mounting holes 14 for connecting a larger primary current. The middle of the shunt 10 is made of manganese copper, which has the characteristics of stable resistivity and little change with temperature. The nominal resistance of the manganese copper part of the shunt 10 has specifications such as 25μΩ and 50μΩ. When current flows through the manganese copper part, the voltage drop caused by the current on the above nominal resistance is the output V of the shunt 10. 分流器10 .

[0054] According to one embodiment of the present invention, the calculation formula for obtaining the first primary current of the current sensor is:

[0055] I=V SHUNT / r t ;

[0056] Among them, V SHUNT is the voltage across the shunt 10, r t is the resistance of the shunt 10 at the current temperature;

[0057] And get r t The calculation formula is:

[0058] r t=R0*(1+R COMP / 10 6 );

[0059] Where R0 is the resistance of the shunt 10 at 25°C; R COMP is the resistance of the shunt 10 at a specific temperature.

[0060] According to one embodiment of the present invention, the resistance R of the shunt 10 at a specific temperature is COMP The calculation formula is:

[0061] R COMP =A*T 2 +B*T+C;

[0062] Wherein, T is temperature, A, B and C are coefficients of the calculation formula, and the coefficients are obtained according to calibration.

[0063] In the above formula, T is the temperature value of the NTC (thermistor), which can be obtained by looking up the table in the NTC specification:

[0064] The above R comp =A*T 2 The A, B, and C values ​​in the +B*T+C formula can be obtained by calibration.

[0065] The above t =R0*(1+R COMP / 10 6 ) where R0 is the resistance of the shunt 10 at 25°C.

[0066] According to one embodiment of the present invention, the magnetic field measuring device 20 is an annular column, and a plurality of chips are evenly distributed along the annular magnetic field measuring device 20. In other words, Figure 1 and Figure 3 As shown, the magnetic field measuring device 20 can be designed as an annular column, and a plurality of chips can be spaced and evenly distributed along the annular magnetic field measuring device 20. The shunt 10 serves as the primary conductor of the current sensor of the annular array of magnetic field measuring chips, and the relative position with the magnetic field measuring chip is fixed, thereby improving the measurement accuracy of the current sensor of the annular array of magnetic field measuring chips.

[0067] According to one embodiment of the present invention, the chip includes: a first chip, a second chip and a third chip, and the first chip, the second chip and the third chip are evenly distributed along the periphery of the magnetic field measurer 20. Figure 3 As shown, the distances between the first chip, the second chip and the third chip and the center of the magnetic field measuring device 20 are R1, R2 and R3 respectively, wherein the magnetic induction intensities measured by the first chip, the second chip and the third chip are B1, B2 and B3 respectively, so as to obtain the average magnetic induction intensity B of the magnetic field measuring device 20. OUT .

[0068] That is, see Figure 1 and Figure 3 The chip mainly consists of a first chip, a second chip and a third chip. The first chip, the second chip and the third chip can be evenly distributed along the periphery of the magnetic field meter 20. The first chip, the second chip and the third chip can be called magnetic field measurement chips. The magnetic field measurement chip can be a single-axis magnetic field measurement chip, a Hall or other single-axis magnetic field measurement chip. The number of magnetic field measurement chips can be greater than three. In the present invention, three magnetic field measurement chips (the first chip, the second chip and the third chip) are taken as an example for specific description.

[0069] like Figure 3 As shown, the distances between the first chip, the second chip and the third chip and the center of the magnetic field measuring device 20 are R1, R2 and R3 respectively, wherein the magnetic induction intensities measured by the first chip, the second chip and the third chip are B1, B2 and B3 respectively, and the average magnetic induction intensity B of the magnetic field measuring device 20 can be obtained. OUT .

[0070] In some specific embodiments of the present invention, the calculation formulas for the magnetic induction intensity measured by the first chip, the second chip and the third chip are respectively:

[0071]

[0072] Sum the magnetic induction intensity values ​​of the three chips (the first chip, the second chip, and the third chip) and then find the average value, then we have:

[0073]

[0074] After the above formula is rearranged, the average magnetic induction intensity B of the magnetic field measuring device 20 is obtained: OUT The calculation formula is:

[0075]

[0076] Among them, B1, B2 and B3 are the magnetic induction intensities measured by the first chip, the second chip and the third chip respectively, B OUT is the average magnetic induction intensity of the magnetic field meter 20, I is the second primary current of the current sensor, R1, R2 and R3 are the distances between the first chip, the second chip and the third chip and the center of the magnetic field meter 20 respectively, and μ0 is the calculation coefficient of the magnetic induction intensity.

[0077] The calculation formula of the second primary current is:

[0078]

[0079] Among them, B OUTis the average magnetic induction intensity of the magnetic field measuring device 20, then the following formula is obtained:

[0080] B OUT =ε·I

[0081] When the current sensor is manufactured, the values ​​of R1, R2, and R3 are determined, so the value of ε is also determined. Therefore, the output B of the current sensor of the ring array OUT It is linearly related to the primary current I. That is, the calculation formula for the second primary current is:

[0082]

[0083] In summary, according to the current sensor of the embodiment of the present invention, the magnetic field measuring device 20 is integrated on the shunt 10 to form a current sensor based on the shunt 10 and the ring array of magnetic field measuring chips, which combines two current testing methods into one, reduces the product volume, and solves the need to use two current measurement methods in specific occasions, thereby improving the versatility of the current sensor. In addition, the first primary current and the second primary current measured by the shunt 10 and the magnetic field measuring device 20 are backed up for each other to achieve functional safety of the product.

[0084] Of course, for those skilled in the art, other structures and working principles of the current sensor are understandable and achievable, and will not be described in detail in the present invention.

[0085] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A current sensor, characterized in that: include: A shunt (10), the shunt (10) being used to measure a first primary current of the current sensor; A magnetic field measurer (20), the magnetic field measurer (20) being arranged on the shunt (10), the magnetic field measurer (20) being provided with a plurality of chips, the magnetic field measurer (20) measuring the second primary current of the current sensor through the plurality of chips, the first primary current and the second primary current being referenced to each other, so as to ensure the measurement safety and measurement accuracy of the current sensor.

2. The current sensor according to claim 1, characterized in that: The shunt (10) comprises a first region (11), a second region (12) and a third region (13), wherein the second region (12) is located between the first region (11) and the third region (13), and the magnetic field measuring device (20) is arranged on the second region (12).

3. The current sensor according to claim 2, characterized in that: A circuit board is provided on the second area (12) of the shunt (10), and a thermistor is welded on the circuit board.

4. The current sensor according to claim 2, characterized in that: The first region (11) and the third region (13) of the diverter (10) are respectively made of red copper material, and the second region (12) is made of manganese copper material.

5. The current sensor according to claim 3, characterized in that: The calculation formula for obtaining the first primary current of the current sensor is: I=V SHUNT / r t ; Among them, V SHUNT is the voltage across the shunt (10), r t is the resistance of the shunt (10) at the current temperature; And get r t The calculation formula is: r t =R0*(1+R COMP / 10 6 ); Wherein, R0 is the resistance of the shunt (10) at 25°C; R COMP is the resistance of the shunt (10) at a specific temperature.

6. The current sensor according to claim 5, characterized in that: The resistance R of the shunt (10) at a specific temperature COMP The calculation formula is: R COMP =A*T 2 +B*T+C; Wherein, T is temperature, A, B and C are coefficients of the calculation formula, respectively, and the coefficients are obtained according to calibration.

7. The current sensor according to claim 1, characterized in that: The magnetic field measurer (20) is in the shape of an annular column, and a plurality of the chips are spaced apart and evenly distributed along the annular magnetic field measurer (20).

8. The current sensor according to claim 1, characterized in that: The chip comprises: a first chip, a second chip and a third chip, wherein the first chip, the second chip and the third chip are evenly distributed along the circumference of the magnetic field measuring device (20), and the distances between the first chip, the second chip and the third chip and the center of the magnetic field measuring device (20) are R1, R2 and R3 respectively, wherein the magnetic induction intensities measured by the first chip, the second chip and the third chip are B1, B2 and B3 respectively, so as to obtain an average magnetic induction intensity B of the magnetic field measuring device (20). OUT .

9. The current sensor according to claim 8, characterized in that: The calculation formulas for the magnetic induction intensity measured by the first chip, the second chip and the third chip are respectively: The average magnetic induction intensity B of the magnetic field measuring device (20) OUT The calculation formula is: Wherein, B1, B2 and B3 are the magnetic induction intensities measured by the first chip, the second chip and the third chip respectively, and B OUT is the average magnetic induction intensity of the magnetic field measuring device (20), I is the second primary current of the current sensor, R1, R2 and R3 are respectively the distances between the first chip, the second chip and the third chip and the center of the magnetic field measuring device (20), and μ0 is the calculation coefficient of the magnetic induction intensity.

10. The current sensor according to claim 9, characterized in that: The calculation formula of the second primary current is: Among them, B OUT is the average magnetic induction intensity of the magnetic field measuring device (20).

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