Hall current sensor

Abstract

The utility model discloses a Hall current sensor which comprises an error compensation device connected with a secondary side compensation coil of the sensor, the secondary side compensation coil is connected with the error compensation device, and the error compensation device comprises an analog-to-digital conversion module and a compensation module. The analog-to-digital conversion module is respectively communicated with the secondary compensation coil and the compensation module so as to acquire secondary compensation current, convert the secondary compensation current into a digital signal and transmit the digital signal to the compensation module, and the compensation module is used for performing digital compensation on the secondary compensation current by using a read compensation value. Therefore, the compensated measurement value is obtained.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic instruments, in particular to a Hall current sensor. Background Art

[0002] Currently, the accuracy of closed-loop Hall current sensors on the market is basically 0.5%. However, when the accuracy of closed-loop Hall current sensors needs to be further improved, due to the influence of production process and production environment, there will be a slight error between the actual number of turns of the secondary compensation coil of the closed-loop Hall current sensor and the theoretical number of turns.

[0003] According to the formula I1×N1=I2×N2, where I1 is the primary current (i.e., the current to be measured), N1=1, I2 is the current in the secondary compensation winding, and N2 is the number of turns in the secondary compensation coil. If the actual N2 is not equal to the programmed N2 setting, measurement error will occur. This will cause the primary current measured by the closed-loop Hall effect current sensor to change proportionally, easily exceeding the accuracy of the closed-loop Hall effect current sensor by 0.02%. To overcome this problem, the number of turns must be manually adjusted one by one, which consumes a lot of manpower.

[0004] Prior art CN216816803U discloses a device capable of measuring the number of turns of a coil with an open air gap. This device determines the number of turns of the unknown coil by comparing the measured current of the coil with the standard current of the coil with a known number of turns. However, this technology uses a current transformer to measure the standard current of the coil with a known number of turns, which can only measure alternating current. This has a relatively narrow application range.

[0005] Currently, there is no Hall current sensor that is high-precision, debug-free, and capable of detecting multiple types of currents such as DC, AC, and pulse current. Utility Model Content

[0006] To address the technical problem in the prior art that manual debugging of a Hall current sensor is required to improve its accuracy, the present application proposes a Hall current sensor.

[0007] According to one aspect of the present invention, a Hall current sensor is proposed, comprising an error compensation device connected to a secondary compensation coil in the sensor, the error compensation device comprising an analog-to-digital conversion module and a compensation module, the analog-to-digital conversion module being respectively connected to the secondary compensation coil and the compensation module to collect the secondary compensation current and convert the secondary compensation current into a digital signal and transmit it to the compensation module, the compensation module being used to digitally compensate the secondary compensation current using the read compensation value to obtain a compensated measurement value. An error compensation device is added to the output analog signal of the original hardware. The analog-to-digital conversion module of the error compensation device collects data, and the compensation module processes data, eliminating the need for repeated manual debugging. This reduces manpower while improving product accuracy.

[0008] Preferably, the compensation module includes a single chip microcomputer, a DSP, a programmable logic device or a combinational logic circuit.

[0009] Further preferably, when the compensation module includes a single-chip microcomputer, the single-chip microcomputer is a STM8S003F3 model.

[0010] Preferably, the error compensation device further includes a first storage module, which is connected to the compensation module and is used to store the compensation value.

[0011] Preferably, the sensor further comprises a transceiver module for establishing communication with an external device. The transceiver module facilitates signal output and communication with the external device, and sends the output primary current compensated measurement value to the external device.

[0012] Preferably, the transceiver module includes a communication chip selected from one of the communication protocols RS485, RS232, Bluetooth, WIFI and Zigbee.

[0013] Preferably, the sensor further comprises a second storage module for storing the compensated measurement value.

[0014] Preferably, the sensor further includes an analog output device connected to the compensation module, the analog output device comprising a digital-to-analog conversion module and an analog output module for outputting the compensated measurement value. The primary current compensated measurement value output by the error compensation device is a digital quantity and cannot be directly displayed. Therefore, a digital-to-analog conversion is required for client viewing to convert the digital value into an analog output.

[0015] Preferably, the sensor also includes a magnetic core, a Hall element and a feedback regulation circuit, the Hall element is arranged in the air gap of the magnetic core, the secondary compensation coil is wound on the magnetic core, the primary current passes through the magnetic core and generates the secondary compensation current on the secondary compensation coil, and the feedback regulation circuit is used to adjust the magnitude of the secondary compensation current to achieve magnetic field balance in the air gap.

[0016] Preferably, the device further includes a low-dropout linear regulator (LDO), which is disposed at the front end of the error compensation device and is configured to provide a stable voltage for the error compensation device. The supply voltage of the entire Hall current sensor may differ from that of the error compensation device, and the LDO ensures stable operation of the error compensation device.

[0017] The utility model converts the secondary compensation current generated by the primary current passing through the secondary compensation coil from an analog signal into a digital signal through an error compensation device, and compensates for the turn error of the secondary compensation coil according to the compensation value, so that the measured primary current value is as close to the true value as possible, thereby improving the detection accuracy.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate the embodiments and, together with the description, serve to explain the principles of the present invention. Other embodiments and many of the expected advantages of the embodiments will be readily apparent as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale with respect to each other. Like reference numerals designate corresponding similar parts.

[0020] Figure 1 Shows a schematic structural diagram of an existing Hall current sensor;

[0021] Figure 2 A schematic diagram of the structure of a Hall current sensor according to the present invention is shown;

[0022] Figure 3 A schematic diagram of the structure of a Hall current sensor according to the present invention is shown;

[0023] Figure 4 A schematic diagram of the structure of a Hall current sensor according to the present invention is shown;

[0024] Figure 5 A schematic diagram of the structure of a Hall current sensor according to the present invention is shown;

[0025] Figure 6 A schematic diagram of the structure of a Hall current sensor according to the present invention is shown;

[0026] Figure 7 The figure shows a schematic diagram of the structure of a Hall current sensor according to the present invention.

[0027] 1-primary current; 2-magnetic core; 3-secondary compensation coil; 4-Hall element; 5-secondary compensation current; 6-feedback regulation circuit; 7-low voltage difference linear regulator; 8-error compensation device; 9-compensation module; 10-analog-to-digital conversion module; 11-first storage module; 12-digital-to-analog conversion module; 13-second storage module; 14-analog output device; 15-transceiver module; 16-external device; 17-client; 18-analog output module. DETAILED DESCRIPTION

[0028] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the relevant utility model and are not intended to limit the utility model. It should also be noted that, for ease of description, only portions relevant to the relevant utility model are shown in the accompanying drawings.

[0029] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] Figure 1 This is a schematic diagram of the structure of a conventional Hall effect current sensor, comprising a magnetic core 2, a Hall element 4, a feedback regulation circuit 6, and a secondary compensation coil 3. The Hall element 4 is positioned in the air gap of the magnetic core 2, and the secondary compensation coil 3 is wound around the magnetic core 2. The primary current 1 flows through the magnetic core 2 and generates a secondary compensation current 5 in the secondary compensation coil 3. The feedback regulation circuit 6 adjusts the magnitude of the secondary compensation current 5 to achieve magnetic field balance in the air gap. By measuring the value of the secondary compensation current 5, the measured value of the primary current 1 can be calculated.

[0031] Example 1

[0032] Figure 2 FIG. 1 is a schematic diagram of the structure of a Hall current sensor according to the present invention, as shown in FIG. Figure 2 As shown, a Hall current sensor includes a magnetic core 2, a Hall element 4, a feedback regulation circuit 6, a secondary compensation coil 3, an error compensation device 8, and a first storage module 11. It can be appreciated that the error may be a sensor batch manufacturing error such as an error in the number of coil turns.

[0033] The error compensation device 8 is connected to the secondary compensation coil 3 in the sensor and includes an analog-to-digital conversion module 10 and a compensation module 9. The analog-to-digital conversion module 10 is in communication with the secondary compensation coil 3 and the compensation module 9, respectively, to collect the secondary compensation current 5, convert the secondary compensation current 5 into a digital signal, and transmit the digital signal to the compensation module 9. The compensation module 9 is used to digitally compensate the secondary compensation current 5 using the compensation value read to obtain a compensated measurement value.

[0034] Among them, the analog-to-digital conversion module 10 is set to solve the problem that the collected secondary compensation current 5 is an analog quantity that cannot be calculated and needs to be converted into a digital quantity before it can be calculated. The compensation module 9 is connected to the first storage module 11, and the first storage module 11 is used to store the compensation value. The compensation module 11 is used to use the read compensation value to digitally compensate the secondary compensation current 5 to obtain the measured value output after the primary current 1 is compensated. In a general example, the compensation value is pre-stored in the first storage module 11. For each batch of sensors, different coil turn errors may be encountered, etc. The compensation value can be changed to achieve more accurate actual compensation. Although the above error compensation module is specifically designed for the coil turn error in the specification, it can be understood that the error compensation module can also be applied to other types of product batch manufacturing errors.

[0035] In a specific embodiment, the compensation module 9 includes a single-chip microcomputer, a DSP, a programmable logic device, or a combinational logic circuit. In an optional example, the compensation module 9 is implemented using a single-chip microcomputer model STM8S003F3, because the single-chip microcomputer has the advantages of low cost and strong stability. However, it will be understood by those skilled in the art that although the innovation of this application mainly protects the hardware structure rather than software programming, the specific method of using a single-chip microcomputer to calculate digital values ​​is a means known in the art and is not the focus of protection of this application.

[0036] Example 2

[0037] Figure 3 This is a schematic diagram of the structure of a Hall current sensor according to the present invention. Figure 2 Based on the sensor, a transceiver module 15 is added. The transceiver module 15 facilitates signal output and establishes communication with the external device 16, and transmits the compensated measurement value to the external device 16. In a general example, after receiving the compensated measurement value, the external device 16 can issue an alarm based on the number, value, and time of abnormalities in the received compensated measurement value, prompting the operator to check the sensor and re-debug it.

[0038] In a specific embodiment, the transceiver module 15 includes a communication chip selected from one of the communication protocols RS485, RS232, Bluetooth, WIFI and Zigbee. Preferably, the transceiver module adopts an RS485 communication chip, which is connected to the compensation module to realize communication connection between the compensation module and the outside.

[0039] Example 3

[0040] Figure 4 This is a schematic diagram of the structure of a Hall current sensor according to the present invention. Figure 2 Based on the above, an analog output device 14 is added. The compensation module 9 is connected to the analog output device 14. The analog output device 14 includes a digital-to-analog conversion module 12 and an analog output module 18 to output the compensated measurement value to the client 17. The measured value of the primary current after processing and output by the error compensation device 8 is a digital quantity and cannot be directly displayed. Therefore, the analog output device 14 converts the digital quantity into an analog output so that the client can directly view it.

[0041] Example 4

[0042] Figure 5 This is a schematic diagram of the structure of a Hall current sensor according to the present invention. Figure 2 On the basis of the above, a second storage module 13 is added. The second storage module 13 can store and record the measured value and time of the primary current 1 after compensation for easy viewing. In a general example, the second storage module 13 can also record the number, value and time of the compensated measured value of the output abnormality within an interval.

[0043] Although the first storage module and the second storage module are shown with different reference numerals in the figure, it can be appreciated that the first storage module and the second storage module can be separate memories. However, in an alternative example, the first storage module 11 and the second storage module 13 can be integrated into the same memory. In a further alternative example, the first storage module, the second storage module, and the compensation module are integrated into the same chip.

[0044] Example 5

[0045] Figure 6 This is a schematic diagram of the structure of a Hall current sensor according to the present invention. Figure 2 On the basis of the above, a low-voltage-dropout linear regulator 7 is additionally provided. The low-voltage-dropout linear regulator 7 is provided at the front end of the error compensation device 8 to provide a stable voltage for the error compensation device 8. In an optional example, the power supply voltage of the entire Hall current sensor is 15V, but the error compensation device 8 only requires a 5V power supply. Therefore, the low-voltage-dropout linear regulator 7 is provided at the front end of the error compensation device 8 to provide a stable voltage.

[0046] Example 6

[0047] Figure 7 This is a schematic diagram of the device structure of a Hall current sensor according to the utility model, including a magnetic core 2, a Hall element 4, a feedback adjustment circuit 6, a secondary compensation coil 3, an error compensation device 8, a low-voltage difference linear regulator 7, an analog output device 14, a transceiver module 15, a first storage module 11, and a second storage module 13.

[0048] Taking the Hall current sensor with a measurement range of 0A-300A proposed in this utility model as an example, the specific compensation calculation method is: the current value of the primary current is I1, the theoretical number of turns of the secondary compensation coil 3 is N 2设定 , assume that the input primary current is 50A. I1=50A, N1=1 and N 2设定 All are known, according to the formula I1×N1=I2×N2, we can get the theoretical I 2设定 .

[0049] With unknown number of turns N 2实际 When the primary current I1 of 50A passes through the conductor, an I 2实际 , if I 2实际 ≠I 2设定 , then it is proved that N 2实际 ≠N 2设定 , according to I 2实际 and I 2设定 The difference between the two endpoints and the middle value of the Hall current sensor is used to obtain a compensation value. The two endpoints and the middle value of the Hall current sensor are measured to obtain multiple compensation values, and then the average value is taken as the compensation value of the current sensor.

[0050] Assign the compensation value to I 2实际 The current sensor measures the value I1, which is compensated by N 2实际 With N 2设定 The exact value of the error I 1设定 .

[0051] The errors in the number of turns of coils within the same batch are generally similar, so there is no need to perform error compensation calculations on each coil within the batch. Errors in the secondary compensation coils often occur, and the device proposed in this utility model can significantly improve product accuracy and significantly reduce labor maintenance costs.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A Hall current sensor, characterized in that: It includes an error compensation device connected to the secondary compensation coil in the sensor, and the error compensation device includes an analog-to-digital conversion module and a compensation module. The analog-to-digital conversion module is respectively connected to the secondary compensation coil and the compensation module to collect the secondary compensation current and convert the secondary compensation current into a digital signal and transmit it to the compensation module. The compensation module is used to use the read compensation value to digitally compensate the secondary compensation current to obtain a compensated measurement value.

2. The Hall current sensor according to claim 1, characterized in that: The compensation module includes a single chip microcomputer, a DSP, a programmable logic device or a combinational logic circuit.

3. The Hall current sensor according to claim 2, characterized in that: When the compensation module includes a single chip microcomputer, the single chip microcomputer is selected as STM8S003F3.

4. The Hall current sensor according to claim 1, wherein: The error compensation device further includes a first storage module, which is connected to the compensation module and is used to store the compensation value.

5. The Hall current sensor according to claim 1, wherein: It also includes a transceiver module for establishing communication with external devices.

6. The Hall current sensor according to claim 5, characterized in that: The transceiver module includes a communication chip selected from one of the communication protocols RS485, RS232, Bluetooth, WIFI and Zigbee.

7. The Hall current sensor according to any one of claims 1 to 6, characterized in that: A second storage module is also included for storing the compensated measurement value.

8. The Hall current sensor according to claim 1, wherein: The sensor further comprises an analog output device connected to the compensation module, wherein the analog output device comprises a digital-to-analog conversion module and an analog output module for outputting the compensated measurement value.

9. The Hall current sensor according to claim 1, wherein: The sensor also includes a magnetic core, a Hall element and a feedback regulation circuit. The Hall element is arranged in the air gap of the magnetic core, the secondary compensation coil is wound on the magnetic core, the primary current passes through the magnetic core and generates the secondary compensation current on the secondary compensation coil, and the feedback regulation circuit is used to adjust the magnitude of the secondary compensation current to achieve magnetic field balance in the air gap.

10. The Hall current sensor according to claim 1, wherein: It also includes a low-voltage difference linear regulator, which is arranged at the front end of the error compensation device.

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