Differential current sensor, measurement method and electronic device

Abstract

The disclosed embodiment discloses a differential current sensor, a measurement method and an electronic device, wherein a plurality of the first magnetic field sensing chips are located on an imaginary circle of the annular circuit board and the circumference of the imaginary circle is equally divided, and the magnetic sensitive axis direction of each of the first magnetic field sensing chips is tangent to the imaginary circle in the same clockwise direction; the number of the second magnetic field sensing chips is consistent with the number of the first magnetic field sensing chips, and the second magnetic field sensing chip and the first magnetic field sensing chip are respectively located on opposite sides of the annular circuit board; on the annular circuit board, the overlapping area of ​​the projection of the second magnetic field sensing chip and the projection of the first magnetic field sensing chip is not less than one-half of the projection area of ​​the first magnetic field sensing chip. In this way, the differential principle can be used to eliminate the interference of the external magnetic field, thereby improving the measurement accuracy of the differential current sensor.

Description

Technical Field

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

[0002] As a key component in the field of power systems and industrial automation, current sensors are essential for accurately monitoring and controlling current. Among them, ring array current sensors are widely used in various current monitoring scenarios due to their advantages such as non-contact measurement, high sensitivity and wide measurement range. However, current sensors are easily affected by external magnetic field interference during the measurement process, resulting in reduced measurement accuracy of current sensors, and may even cause false alarms or system failures. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a new technical solution of a differential current sensor, a measurement method and an electronic device.

[0004] According to one aspect of the present invention, a differential current sensor is provided.

[0005] The differential current sensor comprises:

[0006] An annular circuit board and at least three first magnetic field sensing chips, wherein the plurality of first magnetic field sensing chips are located on an imaginary circle of the annular circuit board and divide the circumference of the imaginary circle into equal parts, and the magnetic sensitive axis direction of each first magnetic field sensing chip is tangent to the imaginary circle in the same clockwise direction;

[0007] second magnetic field sensing chips, the number of the second magnetic field sensing chips is the same as the number of the first magnetic field sensing chips, and the second magnetic field sensing chips and the first magnetic field sensing chips are respectively located on two opposite sides of the annular circuit board;

[0008] On the annular circuit board, an overlapping area between a projection of the second magnetic field sensing chip and a projection of the first magnetic field sensing chip is not less than half of an area of ​​the projection of the first magnetic field sensing chip.

[0009] Optionally, on the annular circuit board, the projection of the second magnetic field sensing chip partially overlaps with the projection of the first magnetic field sensing chip.

[0010] Optionally, the second magnetic field sensing chip has the same size as the first magnetic field sensing chip;

[0011] And / or, the second magnetic field sensing chip has the same shape as the first magnetic field sensing chip.

[0012] Optionally, on the annular circuit board, the projection of the second magnetic field sensing chip completely overlaps with the projection of the first magnetic field sensing chip.

[0013] Optionally, the second magnetic field sensing chip is completely identical to the first magnetic field sensing chip.

[0014] Optionally, both the first magnetic field sensing chip and the second magnetic field sensing chip are single-axis magnetic field sensing chips, the number of the first magnetic field sensing chips is four, and the four first magnetic field sensing chips are respectively located at the quarter points of the circumference of the imaginary circle.

[0015] Optionally, a ratio of a distance from the first magnetic field sensing chip to the center of the imaginary circle to a distance from the first magnetic field sensing chip to an interference source is not less than 1:10.

[0016] Optionally, the first magnetic field sensing chip is a uniaxial TMR chip, a uniaxial AMR chip, a uniaxial GMR chip or a uniaxial Hall chip.

[0017] Optionally, a processing module is further included, and the processing module is used to process the signal collected by the magnetic field sensing chip. The processing module includes at least one of an amplifier, a transmitter and an analog-to-digital converter.

[0018] According to another aspect of the present invention, there is provided a measurement method using the differential current sensor, comprising:

[0019] Place the conductor carrying the current to be measured inside the ring of the annular circuit board;

[0020] The magnetic field signals output by the first magnetic field sensing chip and the second magnetic field sensing chip are respectively collected, and the magnetic field signals generated by the interference sources on both sides of the annular circuit board are respectively collected;

[0021] Perform differential processing and obtain the magnetic field signal generated by the current to be measured.

[0022] According to yet another aspect of the present invention, there is provided an electronic device comprising the differential current sensor.

[0023] One technical effect of the embodiments of the present disclosure is:

[0024] The differential current sensor includes an annular circuit board, at least three first magnetic field sensing cores and a second magnetic field sensing chip. The plurality of the first magnetic field sensing chips are located on an imaginary circle of the annular circuit board and divide the circumference of the imaginary circle into equal parts. The magnetic sensitive axis direction of each of the first magnetic field sensing chips is tangent to the imaginary circle in the same clockwise direction. The number of the second magnetic field sensing chips is consistent with the number of the first magnetic field sensing chips, and the second magnetic field sensing chip and the first magnetic field sensing chip are respectively located on opposite sides of the annular circuit board. On the annular circuit board, the overlapping area of ​​the projection of the second magnetic field sensing chip and the projection of the first magnetic field sensing chip is not less than half of the projection area of ​​the first magnetic field sensing chip. In this way, the differential principle can be used to eliminate the interference of the external magnetic field, thereby improving the measurement accuracy of the differential current sensor. Moreover, there is no need to set up a shielding shell, which also reduces the production cost.

[0025] 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

[0026] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0027] Figure 1 is a front schematic diagram of a differential current sensor according to an embodiment of the present disclosure;

[0028] Figure 2 It is a schematic diagram of the back side of a differential current sensor according to an embodiment of the present disclosure.

[0029] Description of reference numerals:

[0030] 1. Ring-shaped circuit board; 2. First magnetic field sensing chip; 3. Second magnetic field sensing chip. DETAILED DESCRIPTION

[0031] 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.

[0032] 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.

[0033] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0034] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0035] 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.

[0036] The embodiment of the present invention provides a differential current sensor. The differential current sensor is based on the principle of electromagnetic induction and can sense the differential current in the circuit through the coil and magnetic core inside the sensor, and convert it into a voltage signal output that is proportional to the current.

[0037] like Figure 1 and Figure 2 As shown, the differential current sensor provided by the embodiment of the present invention includes:

[0038] An annular circuit board 1 and at least three first magnetic field sensing chips 2, wherein the plurality of first magnetic field sensing chips 2 are located on an imaginary circle of the annular circuit board 1 and divide the circumference of the imaginary circle into equal parts, and the magnetic sensitive axis direction of each first magnetic field sensing chip 2 is tangent to the imaginary circle in the same clockwise direction;

[0039] Second magnetic field sensing chips 3, the number of the second magnetic field sensing chips 3 is the same as the number of the first magnetic field sensing chips 2, and the second magnetic field sensing chips 3 and the first magnetic field sensing chips 2 are respectively located on two opposite sides of the annular circuit board 1;

[0040] On the annular circuit board 1 , an overlapping area between a projection of the second magnetic field sensing chip 3 and a projection of the first magnetic field sensing chip 2 is not less than half of a projection area of ​​the first magnetic field sensing chip 2 .

[0041] The annular circuit board 1 can be made of non-conductive materials such as plastic, ceramic or glass fiber reinforced epoxy resin, which can ensure that it will not interfere with the magnetic field generated by the differential current in the circuit.

[0042] Specifically, the annular circuit board 1 can be designed as a circular ring, a rectangular ring or other annular structures, and the annular circuit board 1 has a central hollow area for the wire of the current to be measured to pass through. In addition, the annular structure design also helps to evenly distribute the magnetic field sensing chip, thereby improving the measurement accuracy of the differential current sensor.

[0043] like Figure 1 and Figure 2As shown, at least three first magnetic field sensing chips 2 are evenly distributed on the same imaginary circle of the annular circuit board 1, and the imaginary circle is kept at a certain distance from the inner circle and the outer circle of the annular circuit board 1, depending on the design requirements. The number of the first magnetic field sensing chips 2 can be three, four, five or more to meet different measurement requirements.

[0044] Among them, the magnetic sensitive axis directions of multiple first magnetic field sensing chips 2, that is, the axes for detecting magnetic field changes, are all tangent to the imaginary circle in the same clockwise direction, so as to ensure that these first magnetic field sensing chips 2 can capture different parts of the circular magnetic field generated by the current to be measured, and can also avoid measurement errors caused by inconsistent magnetic field directions.

[0045] In this way, the plurality of first magnetic field sensing chips 2 can sense the annular magnetic field generated by the current to be measured from different positions, so as to avoid the measurement error caused by single-point measurement, thereby improving the measurement accuracy and measurement reliability of the differential current sensor. Moreover, this layout also ensures that each magnetic field sensing chip can capture different parts of the annular magnetic field generated by the current to be measured, thereby improving the comprehensiveness of the measurement.

[0046] Each first magnetic field sensing chip 2 may be connected to the signal processing unit of the ring-shaped circuit board 1 through a wire or wirelessly to output the sensed magnetic field signal.

[0047] like Figure 1 and Figure 2 As shown, the number of the second magnetic field sensing chips 3 is exactly the same as that of the first magnetic field sensing chips 2, and the two magnetic field sensing chips are arranged in a one-to-one correspondence. That is, the second magnetic field sensing chip 3 is arranged on the other side of the annular circuit board 1 opposite to the first magnetic field sensing chip 2, so as to ensure that the two are on both sides of the same imaginary circle and form a differential measurement structure together.

[0048] This structural symmetry, on the one hand, helps to reduce the measurement error caused by the temperature drift, aging and other intrinsic factors of the annular circuit board 1 or the magnetic field sensing chip; on the other hand, it can also make full use of the space of the annular circuit board 1 to reduce the overall size of the differential current sensor, making the structure of the differential current sensor simple and convenient for mass production.

[0049] On the plane of the annular circuit board 1, the overlapping area between the projection of each second magnetic field sensing chip 3 and the projection of the corresponding first magnetic field sensing chip 2 is set to be no less than one-half of the projection area of ​​the first magnetic field sensing chip 2. That is, the second magnetic field sensing chips 3 on both sides of the annular circuit board 1 partially overlap or completely overlap with the first magnetic field sensing chip 2 to ensure that the second magnetic field sensing chips 3 on both sides of the annular circuit board 1 have sufficient overlapping area with the first magnetic field sensing chip 2, so that the differential principle can be used to eliminate the interference of the external magnetic field, thereby improving the measurement accuracy of the differential current sensor. In addition, there is no need to set up a shielding shell, which also reduces the production cost.

[0050] Specifically, when the current to be measured passes through the wire passing through the center of the annular circuit board 1, an annular magnetic field will be generated around it. The first magnetic field sensing chip 2 and the second magnetic field sensing chip 3 are respectively located on both sides of the annular magnetic field. Due to the symmetry of their positions and the direction of the magnetic sensitive axis, the first magnetic field sensing chip 2 and the second magnetic field sensing chip 3 can detect magnetic field changes in opposite directions. After that, the signals output from both sides of the annular circuit board 1 are differentially processed to offset the magnetic field interference caused by external environmental factors such as the geomagnetic field and the magnetic field of other electrical equipment, so that the magnetic field signal generated by the current to be measured can be accurately measured.

[0051] The signal processing unit in the differential current sensor can receive the output signals generated by the magnetic field interference from all the first magnetic field sensing chips 2, all the second magnetic field sensing chips 3 and both sides of the annular circuit board 1, and perform differential operations, i.e., subtraction, to obtain the net magnetic field signal of the current to be measured. After amplification, filtering and digital processing, the signal can be further analyzed and calculated by the microprocessor, and finally output a digital signal or analog signal that can represent the magnitude of the current to be measured.

[0052] In addition, the differential current sensor of the present invention can adopt a modular design, and the annular circuit board 1 and the magnetic field sensing chip can be produced and assembled as independent modules. This design not only simplifies the production process and reduces production costs, but also facilitates subsequent integration and maintenance work. Moreover, the differential measurement structure itself has the characteristics of strong anti-interference ability, which can further improve the stability of the differential current sensor. By adjusting the number of magnetic field sensing chips, the flexibility and scalability of the differential current sensor can also be enhanced.

[0053] Optionally, on the annular circuit board 1 , the projection of the second magnetic field sensing chip 3 partially overlaps with the projection of the first magnetic field sensing chip 2 .

[0054] Specifically, the projection of the second magnetic field sensing chip 3 can be set to partially overlap with the projection of the first magnetic field sensing chip 2, and to be staggered with respect to the other part. This can enhance the flexibility of the layout of the magnetic field sensing chips while utilizing the first magnetic field sensing chip 2 and the second magnetic field sensing chip 3 to form an effective differential measurement structure. This allows the relative positions of the plurality of magnetic field sensing chips to be adjusted according to actual needs while maintaining the high-precision measurement of the differential current sensor, so as to further optimize the differential anti-interference capability.

[0055] When the projection of the second magnetic field sensing chip 3 partially overlaps with the projection of the first magnetic field sensing chip 2, the magnetic field changes detected by the first magnetic field sensing chip 2 and the second magnetic field sensing chip 3 on both sides are in opposite directions but have slightly different magnitudes. The difference can be calibrated and stored before measurement to eliminate the influence of the staggered positions of the two magnetic field sensing chips, thereby improving the measurement accuracy of the differential current sensor.

[0056] In addition, the partially overlapping design enables the second magnetic field sensing chip 3 to be arranged more closely around the first magnetic field sensing chip 2, which is convenient for reducing the overall size of the ring-shaped circuit board 1, so as to improve the structural compactness of the differential current sensor, making the differential current sensor easy to integrate with other power equipment. Moreover, the partially overlapping design helps to reduce the measurement error caused by the magnetic field sensing chip itself, such as temperature drift and aging.

[0057] Optionally, the second magnetic field sensing chip 3 has the same size as the first magnetic field sensing chip 2;

[0058] And / or, the second magnetic field sensing chip 3 and the first magnetic field sensing chip 2 have the same shape.

[0059] In one embodiment, the second magnetic field sensing chip 3 and the first magnetic field sensing chip 2 can be arranged to have the same size but be staggered, so that the projection of the second magnetic field sensing chip 3 can overlap with the projection of the first magnetic field sensing chip 2, and the second magnetic field sensing chip 3 and the first magnetic field sensing chip 2 can be used interchangeably, thereby reducing the production difficulty of the differential current sensor.

[0060] In another embodiment, the second magnetic field sensing chip 3 may have the same shape as the first magnetic field sensing chip 2 but a different size, or may have the same shape and size but be staggered. For example, both may be circular, rectangular or other shapes. This may also enable the projection of the second magnetic field sensing chip 3 to partially overlap with the projection of the first magnetic field sensing chip 2.

[0061] In this way, the number, type, size, shape and setting position of the second magnetic field sensing chip 3 and the first magnetic field sensing chip 2 can be adapted according to measurement requirements to form an effective differential measurement structure.

[0062] Optionally, on the annular circuit board 1 , the projection of the second magnetic field sensing chip 3 completely overlaps with the projection of the first magnetic field sensing chip 2 .

[0063] like Figure 1 and Figure 2 As shown, the completely overlapping design enables the second magnetic field sensing chip 3 to be completely opposite to the first magnetic field sensing chip 2, which can reduce the space occupied by the magnetic field sensing chip and greatly reduce the overall size of the differential current sensor, facilitating its miniaturization and integration development.

[0064] Among them, the projections of the second magnetic field sensing chip 3 and the first magnetic field sensing chip 2 completely overlap, so that the two can form an effective differential measurement structure on the opposite sides of the annular circuit board 1, so as to utilize the basic principle of differential measurement, that is, eliminating the interference of the external magnetic field by measuring the difference in magnetic field changes at two symmetrical positions.

[0065] In addition, the completely overlapping design, on the one hand, brings the two magnetic field sensing chips closer physically, which helps optimize thermal management. The heat generated by the differential current sensor during operation can be more effectively transferred and dispersed through the annular circuit board 1, thereby reducing the operating temperature of the magnetic field sensing chip and improving the long-term stability and reliability of the differential current sensor. On the other hand, it can also simplify the alignment and assembly steps in the production process, making it easier to accurately place the two magnetic field sensing chips at the predetermined positions of the annular circuit board 1, thereby improving production efficiency and consistency.

[0066] Optionally, the second magnetic field sensing chip 3 is completely identical to the first magnetic field sensing chip 2 .

[0067] Specifically, the second magnetic field sensing chip 3, which is set at a completely opposite position, is exactly the same as the first magnetic field sensing chip 2, that is, the two chip types and sizes are the same, so that the first magnetic field sensing chip 2 and the second magnetic field sensing chip 3 can detect magnetic field changes of equal magnitude but opposite directions on both sides of the annular circuit board 1. By performing differential processing on the signals output from both sides of the annular circuit board 1, the magnetic field interference caused by external environmental factors such as the earth's magnetic field and the magnetic field of other electrical equipment can be offset, so that the magnetic field signal generated by the current to be measured can be accurately measured.

[0068] Optionally, the first magnetic field sensing chip 2 and the second magnetic field sensing chip 3 are both single-axis magnetic field sensing chips, the number of the first magnetic field sensing chips 2 is four, and the four first magnetic field sensing chips 2 are respectively located at the quarter points of the circumference of the imaginary circle.

[0069] Specifically, the single-axis magnetic field sensing chip can sensitively and accurately capture the change of the magnetic field in a specific direction. When the first magnetic field sensing chip 2 and the second magnetic field sensing chip 3 are located on opposite sides of the annular circuit board 1, they can form an effective differential measurement structure, which is convenient for eliminating the influence of the external interference magnetic field on the measurement result, thereby improving the measurement accuracy of the differential current sensor. Compared with the multi-axis magnetic field sensing chip, the single-axis magnetic field sensing chip has a higher cost performance and wider availability, and can also reduce the difficulty of measurement.

[0070] Among them, the four first magnetic field sensing chips 2 (U1, U2, U3 and U4) are respectively arranged at the quarter points of the circumference of the imaginary circle. This layout ensures that each first magnetic field sensing chip 2 can capture different parts of the annular magnetic field generated by the current to be measured. Through differential operation, internal noise and errors can be further eliminated, and the stability, accuracy and comprehensiveness of the measurement are improved. In addition, the alignment and assembly steps in the production process are simplified, and the magnetic field sensing chip can be more easily placed accurately at the predetermined position during the production process, thereby improving production efficiency and consistency.

[0071] Optionally, a ratio of a distance from the first magnetic field sensing chip 2 to the center of the imaginary circle to a distance from the first magnetic field sensing chip 2 to an interference source is not less than 1:10.

[0072] Specifically, the ratio of the distance from the first magnetic field sensing chip 2 to the center of the imaginary circle, that is, the measurement source, to the distance from the first magnetic field sensing chip 2 to the interference source can be set to be greater than or equal to 1:10, which can ensure that there is a large safety distance between the first magnetic field sensing chip 2 and the interference source, thereby reducing the influence of the external interference source on the measurement result of the first magnetic field sensing chip 2, and improving the measurement accuracy of the differential current sensor. It also enables the differential current sensor to maintain consistent measurement performance during long-term operation, reducing the measurement error caused by external interference.

[0073] Wherein, under the premise of the above-mentioned larger safety distance, the first magnetic field sensing chip 2 can be more flexibly arranged on the ring-shaped circuit board 1. Such flexibility helps to optimize the overall structure of the differential current sensor, making it more compact and easy to integrate.

[0074] Optionally, the first magnetic field sensing chip 2 is a uniaxial TMR chip, a uniaxial AMR chip, a uniaxial GMR chip or a uniaxial Hall chip.

[0075] Specifically, the first magnetic field sensing chip 2 can be set as a single-axis TMR (Tunnel

[0076] Magnetoresistance, tunneling magnetoresistance) chip, single-axis AMR (Anisotropic

[0077] Magnetoresistance, anisotropic magnetoresistance) chip, uniaxial GMR (Giant

[0078] Any one of the giant magnetoresistance (GMR) chip and the uniaxial Hall chip can accurately capture weak magnetic field changes. That is, the first magnetic field sensing chip 2 can accurately measure the annular magnetic field generated by the current to be measured, thereby improving the measurement accuracy. These chips also have good stability and can maintain consistent measurement performance during long-term operation. This helps to reduce measurement errors caused by aging or environmental factors of the differential current sensor, and also improves the long-term reliability of the differential current sensor.

[0079] In addition, the uniaxial TMR chip, uniaxial AMR chip, uniaxial GMR chip and uniaxial Hall chip all have good linearity, that is, there is a linear relationship between the magnetic field strength and the output voltage or current. This also enables the differential current sensor to maintain high accuracy within a wide measurement range and is suitable for current measurements of different sizes. Moreover, these chips also have good environmental adaptability and can maintain stable measurement performance under different temperatures, humidity and electromagnetic environments, allowing the differential current sensor to work normally in harsh industrial environments and provide reliable current monitoring data.

[0080] Optionally, a processing module is further included, and the processing module is used to process the signal collected by the magnetic field sensing chip. The processing module includes at least one of an amplifier, a transmitter and an analog-to-digital converter.

[0081] Specifically, the operator in the differential current sensor can receive the output signals generated by the magnetic field interference from all the first magnetic field sensing chips 2, all the second magnetic field sensing chips 3 and both sides of the annular circuit board 1, perform differential operations, i.e., subtraction, and obtain the net magnetic field signal of the current to be measured. The signal can be amplified, filtered and digitized by the processing module, and then further analyzed and calculated by the microprocessor, and finally output a digital signal or analog signal that can represent the magnitude of the current to be measured.

[0082] Among them, through the fine processing of the processing module, the differential current sensor can more accurately capture and measure the changes in the magnetic field, thereby achieving high-precision monitoring of the current, helping to reduce measurement errors and uncertainties caused by improper signal processing, and also improving the accuracy and reliability of the data. In addition, the design of the processing module also enables the differential current sensor to be customized and optimized according to different application requirements. For example, by adjusting the gain of the amplifier, the output range of the transmitter and other parameters, flexible adjustment of different current ranges and measurement accuracy can be achieved.

[0083] In addition, the processing module also provides a wealth of interfaces and communication protocols to facilitate the connection and communication between the differential current sensor and various external devices and systems, which helps to realize the networking, remote monitoring and intelligent management of the differential current sensor.

[0084] The present invention also provides a measurement method using the differential current sensor, comprising:

[0085] S1. The conductor carrying the current to be measured is placed in the ring of the annular circuit board 1;

[0086] The current to be measured located in the circular ring of the annular circuit board 1 , that is, in the hollow area, can generate an annular magnetic field.

[0087] S2. Collect the magnetic field signals output by the first magnetic field sensing chip 2 and the second magnetic field sensing chip 3, respectively, and collect the magnetic field signals generated by the interference sources on both sides of the annular circuit board 1;

[0088] The following description is made by taking the first magnetic field sensing chips 2 (U1, U2, U3 and U4) and the second magnetic field sensing chips 3 (U11, U21, U31 and U41) as examples in which they all overlap and collect voltage signals.

[0089] The first magnetic field sensing chip 2 (U1, U2, U3 and U4) and the second magnetic field sensing chip 3 (U11, U21, U31 and U41) can detect magnetic field changes of equal magnitude but opposite directions on both sides of the annular circuit board 1. That is, V1 = -V11, V2 = -V21, V3 = -V31, V4 = -V41.

[0090] The magnetic field signals generated by the interference sources on both sides of the annular circuit board 1 are Vfront interference source and Vback interference source respectively, and Vfront interference source=-Vback interference source.

[0091] S3. Perform differential processing and obtain the magnetic field signal generated by the current to be measured.

[0092] The voltage signals output from both sides of the ring-shaped circuit board 1 are differentially processed.

[0093] Among them, Vfront = V1 + V2 + V3 + V4 + Vfront interference source;

[0094] Vbackside = V11 + V21 + V31 + V41 + Vbackside interference source;

[0095] Differential processing and get Vtotal = Vfront - Vback = 2 (V1 + V2 + V3 + V4)

[0096] In this way, the magnetic field interference caused by external environmental factors such as the earth's magnetic field and the magnetic field of other electrical equipment can be offset, so that the magnetic field signal generated by the current to be measured can be accurately measured. After amplification, filtering and digital processing, the magnetic field signal can be further analyzed and calculated by the microprocessor, and finally output a digital signal or analog signal that can represent the magnitude of the current to be measured.

[0097] In other embodiments, when the first magnetic field sensing chip 2 and the second magnetic field sensing chip 3 partially overlap, the misalignment difference between the two can be calibrated before measurement to eliminate the influence of the misaligned positions of the two magnetic field sensing chips. The remaining measurement steps are the same as those for complete overlap and are not described in detail here.

[0098] The present invention also provides an electronic device, comprising the above-mentioned differential current sensor.

[0099] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0100] 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 differential current sensor, characterized in that: include: An annular circuit board (1) and at least three first magnetic field sensing chips (2), wherein the plurality of first magnetic field sensing chips (2) are located on an imaginary circle of the annular circuit board (1) and divide the circumference of the imaginary circle into equal parts, and the magnetic sensitive axis direction of each first magnetic field sensing chip (2) is tangent to the imaginary circle in the same clockwise direction; Second magnetic field sensing chips (3), the number of the second magnetic field sensing chips (3) is the same as the number of the first magnetic field sensing chips (2), and the second magnetic field sensing chips (3) and the first magnetic field sensing chips (2) are respectively located on two opposite sides of the annular circuit board (1); On the annular circuit board (1), an overlapping area between a projection of the second magnetic field sensing chip (3) and a projection of the first magnetic field sensing chip (2) is not less than half of the projection area of ​​the first magnetic field sensing chip (2).

2. The differential current sensor according to claim 1, characterized in that: On the annular circuit board (1), the projection of the second magnetic field sensing chip (3) partially overlaps with the projection of the first magnetic field sensing chip (2).

3. The differential current sensor according to claim 2, characterized in that: The second magnetic field sensing chip (3) has the same size as the first magnetic field sensing chip (2); And / or, the second magnetic field sensing chip (3) has the same shape as the first magnetic field sensing chip (2).

4. The differential current sensor according to claim 1, characterized in that: On the annular circuit board (1), the projection of the second magnetic field sensing chip (3) completely overlaps with the projection of the first magnetic field sensing chip (2).

5. The differential current sensor according to claim 4, characterized in that: The second magnetic field sensing chip (3) is completely identical to the first magnetic field sensing chip (2).

6. The differential current sensor according to claim 1, characterized in that: The first magnetic field sensing chip (2) and the second magnetic field sensing chip (3) are both single-axis magnetic field sensing chips, the number of the first magnetic field sensing chips (2) is four, and the four first magnetic field sensing chips (2) are respectively located at the quarter points of the circumference of the imaginary circle.

7. The differential current sensor according to claim 1, characterized in that: The ratio of the distance from the first magnetic field sensing chip (2) to the center of the imaginary circle to the distance from the first magnetic field sensing chip (2) to the interference source is not less than 1:

10.

8. The differential current sensor according to claim 1, characterized in that: The first magnetic field sensing chip (2) is a single-axis TMR chip, a single-axis AMR chip, a single-axis GMR chip or a single-axis Hall chip.

9. The differential current sensor according to claim 1, characterized in that: It also includes a processing module, which is used to process the signal collected by the magnetic field sensing chip. The processing module includes at least one of an amplifier, a transmitter and an analog-to-digital converter.

10. A measurement method using the differential current sensor according to any one of claims 1 to 9, characterized in that: include: Place the conductor carrying the current to be measured inside the ring of the annular circuit board; The magnetic field signals output by the first magnetic field sensing chip and the second magnetic field sensing chip are respectively collected, and the magnetic field signals generated by the interference sources on both sides of the annular circuit board are respectively collected; Perform differential processing and obtain the magnetic field signal generated by the current to be measured.

11. An electronic device, characterized in that: A differential current sensor comprising any one of claims 1 to 9.

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