A calibration device and method for a clamp current sensor

Abstract

The present invention discloses a calibration device for a clamp-type current sensor, comprising a bracket, a carrier back plate, a plurality of fixed straps, a guide wire, a plurality of different types of centering wheels and eccentric wheels, a universal wheel that can be fixed at the bottom of the bracket; the carrier back plate is arranged on the bracket, and grooves are arranged at the upper center and the lower center of the carrier back plate; a plurality of fixed straps are arranged in an inverted bow shape and fixed on the carrier back plate, the guide wire is detachably fixed in the fixed straps, the guide wire after being fixed is in an inverted bow shape on the carrier back plate, the inverted bow shape has smooth corners, and both ends of the guide wire pass through the groove at the lower part of the carrier back plate; a plurality of different types of centering wheels and eccentric wheels are suspended on the guide wire at the groove at the upper part of the carrier back plate. The present invention also discloses a calibration method for a clamp-type current sensor. The present invention proposes a calibration device that is convenient to move, simple to assemble, practical, stable, and meets regulatory requirements, and a method for realizing automatic calibration of a clamp-type current sensor, so that the current sensor parameters meet the application requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of sensor calibration, and in particular to a calibration device and method for a clamp current sensor. Background Art

[0002] During the automobile testing process, it is necessary not only to monitor the control signals of ACU, ECU, etc., but also to quickly and accurately measure the airbag detonation current and the driving current of the automobile actuator. The clamp current sensor based on the Hall effect is an ideal test choice. Before the clamp current sensor is used in the above tests, it is necessary to calibrate the clamp current sensor itself to ensure that its performance indicators meet the requirements to ensure the accurate transmission of the value parameters. At the same time, when the clamp current sensor is widely used, it needs to be calibrated regularly to ensure that the parameters meet the requirements of actual use.

[0003] At present, the devices and methods for calibrating clamp current sensors mainly have the following problems: 1) From the perspective of the device, the device is fixed and cannot be quickly moved or converted according to actual requirements, the calibration efficiency is slow and the disassembly and assembly are cumbersome; 2) From the perspective of the manual reading method, the measurement accuracy of the traditional digital meter is poor and cannot meet the measurement requirements of the output current of the clamp current sensor. During manual calibration, the input signal and the output signal are not recorded synchronously, resulting in large errors; and because manual reading will be performed before the output is stable, the data difference and uncertainty are relatively large, and the operation efficiency is also low; 3) From the perspective of the method of using standard clamp current sensor calibration, a standard clamp current sensor is used as the data source, and the data is compared with the clamp current sensor to be calibrated. Although the data acquisition is synchronized, the performance of the standard clamp current sensor itself will change due to time and environment. The calibration error and uncertainty brought by this method are also large. Summary of the invention

[0004] The object of the present invention is to provide a calibration device and method for a clamp current sensor to solve the deficiencies of the prior art.

[0005] The present invention adopts the following technical solutions:

[0006] A calibration device for a clamp-type current sensor includes a bracket, a carrier back plate, a plurality of fixing straps, a guide wire, a plurality of centering wheels of different models, and a plurality of eccentric wheels of different models.

[0007] The bottom of the bracket is provided with a fixed universal wheel;

[0008] The carrier back plate is arranged on the bracket, a groove is arranged at the center of the upper part of the carrier back plate, and a groove is arranged at the center of the lower part of the carrier back plate;

[0009] Several fixed cable ties are arranged in an inverted bow shape and fixed on the carrier back plate.

[0010] The guide wire can be detachably fixed in a plurality of fixing straps. After being fixed, the guide wire is in an inverted bow shape on the carrier back plate. The inverted bow shape of the guide wire has smooth corners. Both ends of the guide wire pass through the groove at the lower part of the carrier back plate. The length of the guide wire between the two ends of the guide wire and the groove at the lower part of the carrier back plate is long enough. The two ends of the guide wire are respectively used to connect the electronic load and the current source.

[0011] Several different types of centering wheels and several different types of eccentric wheels are hung on the guide wire at the groove on the upper part of the carrier back plate, and the clamp-type current sensor to be calibrated is fixed on the corresponding centering wheel or eccentric wheel before calibration.

[0012] Furthermore, several fixing cable ties are arranged in one, two or more inverted bow shapes and fixed on the carrier back plate; there are one, two or more guide wires with different thicknesses, and the guide wires of different thicknesses can be detachably fixed in the fixing cable ties of different inverted bow shapes.

[0013] Furthermore, the bracket is provided with a groove, and the carrier back plate can be removed and placed in the groove.

[0014] Furthermore, the outer diameter of the centering wheel, the outer diameter of the eccentric wheel and the inner diameter of the magnetic ring of the corresponding clamp-type current sensor match; the inner diameter of the centering wheel, the inner diameter of the eccentric wheel and the outer diameter of the corresponding guide wire match.

[0015] Furthermore, the bracket is made of metal or plastic, and the carrier back plate, the fixing tie, the centering wheel and the eccentric wheel are made of plastic.

[0016] Furthermore, during calibration, the two ends of the guide wire are respectively connected to an electronic load and a current source, the clamp current sensor to be calibrated is fixed on the corresponding centering wheel or eccentric wheel on the guide wire, and the clamp current sensor to be calibrated is connected to a data acquisition device and an excitation voltage source.

[0017] The method for calibrating using the calibration device of the clamp current sensor comprises the following steps:

[0018] Step 1, the electronic load and the current source are respectively connected to the two ends of the corresponding guide wire, and a loop is formed between the current source, the calibration device, and the electronic load; the clamp current sensor to be calibrated is fixed on the corresponding centering wheel on the guide wire, and the clamp current sensor to be calibrated is connected to the data acquisition device and the excitation voltage source;

[0019] Step 2, the electronic load is connected to the PC end, and the PC end is used to control the electronic load to provide an input current signal to the clamp current sensor to be calibrated, and the indication of the electronic load is fed back to the PC end; the excitation voltage source is connected to the PC end, and the PC end is used to control the excitation voltage source to provide an excitation voltage to the clamp current sensor to be calibrated; the data collector is connected to the PC end, and the PC end is used to control the data collector to collect the output signal of the clamp current sensor to be calibrated, and the data collector feeds the collected data back to the PC end; set parameters on the PC end, including the model, serial number, calibration range, and excitation voltage of the clamp current sensor to be calibrated;

[0020] Step 3: Turn on the excitation voltage source, electronic load, and current source;

[0021] Step 4. The PC end divides the calibration into N calibration points according to the calibration range of the clamp current sensor to be calibrated, controls the electronic load to input current from 0 to N and then to 0 calibration points, controls the data acquisition device to start recording the current output voltage signal value of the clamp current sensor when the input current and output signal are stable, and feeds back the input current value and the output voltage signal value to the PC end interface, forming a coordinate system with x and y as the current and voltage as the two-dimensional arrays, which can be displayed on the interface in real time, thereby completing a calibration process for the forward and reverse travel of the clamp current sensor; after repeating this calibration process multiple times, average processing is performed on x and y;

[0022] Step 5: After the calibration is completed, the PC controls to turn off the current source, electronic load, and excitation voltage source;

[0023] Step 6. Then select the parameters to be displayed on the PC interface, including zero output, full scale output, sensitivity, and nonlinearity;

[0024] Step 7. After obtaining the above parameters, compare them with the calibration requirements. If they meet the requirements, choose to output the Excel report, so that a complete calibration report can be generated; if there are any problems, recalibrate or repair the clamp current sensor.

[0025] Furthermore, after the calibration process in step 4 is repeated 2-3 times, x and y are averaged.

[0026] Furthermore, the data logger model is NI PCI 6154.

[0027] Furthermore, when it is necessary to calibrate the uniformity of the magnetic field strength inside the magnetic ring of the clamp current sensor, fix the clamp current sensor on the corresponding eccentric wheel on the guide wire, and follow the above steps to obtain the parameters of the magnetic ring of the clamp current sensor in different directions, including zero point output, full-scale output, sensitivity, and nonlinearity.

[0028] Beneficial effects of the present invention:

[0029] According to the requirement of the regulations that the distance between all other current-carrying conductors (electronic loads, current sources) and the calibrated clamp current sensor should be greater than 0.5m, the present invention proposes a calibration device that is easy to move, simple to assemble, practical, stable, and meets the requirements of the regulations, and a method for realizing automatic calibration of the clamp current sensor, so that the current sensor parameters meet the application requirements. In terms of the calibration method, the problem of errors caused by manual operation of traditional digital tables for calibration is solved, and the problem of calibration errors caused by the unstable performance of the standard source itself is reduced. Not only are the data parameters obtained when calibrating the clamp current sensor more reliable, but the automated calibration process also saves time for operators and greatly improves the calibration efficiency.

[0030] Advantages of the calibration device of the clamp current sensor of the present invention:

[0031] 1. ① It can install current guide wires of different thicknesses, centering wheels and eccentric wheels of different types, which is convenient for testing and calibrating different types of clamp current sensors (including different calibration ranges and different inner diameters of magnetic rings); ② The installation method of the current guide wire (the guide wire is in an inverted bow shape on the carrier back plate, the inverted bow corners are smooth, and the length of the guide wire between the two ends of the guide wire and the groove at the bottom of the carrier back plate is long enough) ensures that the magnetic field between the wires has the lowest impact on the test and calibration results; ③ The carrier back plate, fixing tie, centering wheel and eccentric wheel are made of plastic, which is non-conductive and will not affect the measurement results; ④ For clamp current sensors, this device is more practical.

[0032] 2. ① The centering ring can make the guide wire located at the center of the clamp current sensor to ensure the accuracy of the test data; ② During the test, the eccentric ring can be used to calibrate the sensitivity, nonlinearity and other parameters of the clamp current sensor in different directions such as the upper, lower, left and right directions of the magnetic ring, as an indicator for calibrating the uniformity of the magnetic field strength inside the magnetic ring of the clamp current sensor to ensure the reliability of the results.

[0033] 3. ① The design of the fixed universal wheel enables it to be moved with use, saving space. Compared with the previous fixed device, it is more flexible and versatile, and ensures that the distance between the calibrated clamp current sensor and the electronic load and current source is greater than the required distance, reducing the influence of the geomagnetic field; ② The design of the fixed universal wheel can easily move the calibration device to test the leakage magnetic phenomenon of the clamp current sensor in different directions. Compared with the previous fixed device, this flexible device is more convenient and practical.

[0034] Advantages of the calibration method of the clamp current sensor of the present invention:

[0035] 1. The data logger has higher measurement accuracy. At the same time, the performance of the data logger itself is very stable. This stability will not change due to time or environment, and has little effect on the calibration results of the clamp current sensor. In addition, during automatic calibration, the PC terminal reads the input signal and output signal synchronously. Compared with manual operation of the digital meter reading, this automatic calibration method is easier to meet the calibration requirements;

[0036] 2. The calibration method of the present invention can stably calibrate the clamp current sensor, reduce the calibration working time, and improve the working efficiency;

[0037] 3. The entire calibration process, except for the installation process, which requires human participation, is completed by the PC, and a large number of reports and data are stored on the PC, which is convenient for searching and updating, saving manpower and time costs, and ensuring the safety and reliability of the results. Compared with other methods of using digital meters to test the output signal of the clamp current sensor, the method of the present invention is more reliable and practical.

[0038] 4. The calibration results can be displayed in real time on the PC, which is more vivid, intuitive and easy to understand. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of a calibration device for a clamp current sensor of the present invention.

[0040] Figure 2 It is a front schematic diagram of a calibration device for a clamp current sensor of the present invention.

[0041] Figure 3 for Figure 1 An enlarged schematic diagram of the guide wire portion at the groove on the upper portion of the carrier back plate.

[0042] Figure 4 This is a schematic diagram of the structure of the clamp current sensor.

[0043] Figure 5 Schematic diagram of the structure of different types of clamp current sensors.

[0044] Figure 6 It is a schematic diagram of a calibration method of a clamp current sensor of the present invention.

[0045] Figure 7 It is a schematic flow chart of the calibration method of the clamp current sensor of the present invention.

[0046] Figure 8 Schematic diagram of specific calibration results (the horizontal axis x is the input current of the electronic load to the clamp current sensor, the vertical axis y is the output voltage signal of the clamp current sensor, and each point in the figure represents a calibration point). DETAILED DESCRIPTION

[0047] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] A calibration device for a clamp current sensor, such as Figure 1-5 As shown, it includes a bracket 1, a carrier back plate 2, a plurality of fixing straps 3, a guide wire 4, a plurality of centering wheels 5 of different models, and a plurality of eccentric wheels 6 of different models.

[0049] The bottom of the bracket 1 is provided with a fixed universal wheel 7;

[0050] The carrier back plate 2 is disposed on the bracket 1, preferably detachably disposed on the bracket 1, which can be realized by the following structure, but is not limited thereto: the bracket 1 is provided with a groove, and the carrier back plate 2 is placed in the groove. A groove is provided at the center of the upper part of the carrier back plate 2, and a groove is provided at the center of the lower part of the carrier back plate 2;

[0051] A plurality of fixing straps 3 are arranged in an inverted arc shape in one, two or more circles and fixed on the carrier back plate 2. Figure 1 and Figure 2 Two circles are shown;

[0052] The guide wire 4 is one, two or more. Figure 1 and Figure 2 As shown in the figure, there are two wires of different thicknesses. The guide wires 4 of different thicknesses can be detachably fixed in the fixing straps 3 of different inverted bow shapes. The fixed guide wires 4 are inverted bow shapes on the carrier back plate 2. The inverted bow corners of the guide wires 4 are smooth. The two ends of the guide wires 4 pass through the grooves at the lower part of the carrier back plate 2. The length of the guide wires 4 between the two ends of the guide wires 4 and the grooves at the lower part of the carrier back plate 2 is long enough. The two ends of the guide wires 4 are respectively used to connect the electronic load and the current source;

[0053] Several different types of centering wheels 5 and eccentric wheels 6 have different outer diameters and inner diameters. The outer diameters of the centering wheels 5 and eccentric wheels 6 match the inner diameters of the magnetic rings of the corresponding clamp-type current sensors 8; the inner diameters of the centering wheels 5 and eccentric wheels 6 match the outer diameters of the corresponding guide wires 4. Several different types of centering wheels 5 and eccentric wheels 6 are suspended on the guide wires 4 at the grooves on the upper part of the carrier back plate 2, and the clamp-type current sensors 8 to be calibrated are fixed on the corresponding centering wheels 5 or eccentric wheels 6 before calibration.

[0054] The bracket 1 is made of metal or plastic, such as aluminum. The carrier back plate 2, the fixing strap 3, the centering wheel 5, and the eccentric wheel 6 are made of plastic.

[0055] During calibration, the two ends of the guide wire 4 are connected to an electronic load and a current source respectively, the clamp current sensor 8 to be calibrated is fixed on the corresponding centering wheel 5 or eccentric wheel 6 on the guide wire 4, and the clamp current sensor 8 to be calibrated is connected to a data acquisition device and an excitation voltage source.

[0056] A method for calibrating using the calibration device of the clamp current sensor is as follows: Figure 6 and 7 As shown, the following steps are included:

[0057] Step 1, the electronic load and the current source are respectively connected to the two ends of the corresponding guide wire 4, and a loop is formed between the current source, the calibration device, and the electronic load; the clamp current sensor 8 to be calibrated is fixed on the corresponding centering wheel 5 on the guide wire 4, and the clamp current sensor 8 to be calibrated is connected to the data acquisition device and the excitation voltage source;

[0058] Step 2, the electronic load is connected to the PC end, and the PC end is used to control the electronic load to provide an input current signal to the clamp current sensor 8 to be calibrated, and the indication of the electronic load is fed back to the PC end; the excitation voltage source is connected to the PC end, and the PC end is used to control the excitation voltage source to provide an excitation voltage to the clamp current sensor 8 to be calibrated; the data acquisition device is connected to the PC end, and the PC end is used to control the data acquisition device to collect the output signal of the clamp current sensor 8 to be calibrated, and the data acquisition device feeds back the collected data to the PC end; set parameters on the PC end, including the model, serial number, calibration range, and excitation voltage of the clamp current sensor 8 to be calibrated;

[0059] Step 3: Turn on the excitation voltage source, electronic load, and current source;

[0060] Step 4, the PC end divides the calibration into N calibration points according to the calibration range of the clamp current sensor 8 to be calibrated, controls the electronic load to input current from 0 to N and then to 0 calibration points, controls the data acquisition device to start recording the current output voltage signal value of the clamp current sensor 8 when the input current and output signal are stable, and feeds back the input current value and the output voltage signal value to the PC end interface, forming a coordinate system with x and y as two-dimensional arrays of current and voltage respectively, and can be displayed on the interface in real time, thereby completing a calibration process of the positive and negative strokes of the clamp current sensor 8 (the process in which the current rises from 0 to the calibration range according to each calibration point is the positive calibration stroke, and conversely, the process in which the current goes from the calibration range to 0 according to each calibration point is the negative calibration stroke, that is, 0-calibration range-0); after repeating this calibration process multiple times, such as 2-3 times, x and y are averaged;

[0061] Step 5: After the calibration is completed, the PC controls to turn off the current source, the electronic load, and the excitation voltage source to prevent the clamp current sensor 8 from being damaged by misoperation;

[0062] Step 6. Then select the parameters to be displayed on the PC interface, including zero output, full scale output, sensitivity, and nonlinearity;

[0063] Step 7. After obtaining the above parameters, compare them with the calibration requirements. If they meet the requirements, choose to output the Excel report, so that a complete calibration report can be generated; if there are any problems, recalibrate or repair the clamp current sensor 8.

[0064] The data acquisition device of the present invention uses NI PCI 6154 (National Instruments, Inc., NI), and the clamp current sensor of model JEBOOL JCS06D (Hangzhou Jipu Technology Co., Ltd., JEBOOL) with a range of 10A is calibrated according to the above steps. The calibration results are as follows: Figure 8 shown.

[0065] When it is necessary to calibrate the uniformity of the magnetic field strength inside the magnetic ring of the clamp current sensor 8, fix the clamp current sensor 8 on the corresponding eccentric wheel 6 on the guide wire 4, and follow the above steps to obtain the parameters of the magnetic ring of the clamp current sensor 8 in different directions, including zero point output, full-scale output, sensitivity, and nonlinearity.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A calibration device for a clamp current sensor, characterized in that: It includes a bracket, a carrier back plate, several fixing straps, a guide wire, several different types of centering wheels, and several different types of eccentric wheels. The bottom of the bracket is provided with a fixed universal wheel; The carrier back plate is arranged on the bracket, a groove is arranged at the center of the upper part of the carrier back plate, and a groove is arranged at the center of the lower part of the carrier back plate; Several fixed cable ties are arranged in an inverted bow shape and fixed on the carrier back plate. The guide wire can be detachably fixed in a plurality of fixing straps. After being fixed, the guide wire is in an inverted bow shape on the carrier back plate. The inverted bow shape of the guide wire has smooth corners. Both ends of the guide wire pass through the groove at the lower part of the carrier back plate. The length of the guide wire between the two ends of the guide wire and the groove at the lower part of the carrier back plate is long enough. The two ends of the guide wire are respectively used to connect the electronic load and the current source. Several different types of centering wheels and several different types of eccentric wheels are hung on the guide wire at the groove on the upper part of the carrier back plate, and the clamp-type current sensor to be calibrated is fixed on the corresponding centering wheel or eccentric wheel before calibration.

2. The calibration device for the clamp current sensor according to claim 1, characterized in that: Several fixing straps are arranged in one, two or more inverted bow shapes and fixed on the carrier back plate; there are one, two or more guide wires with different thicknesses, and the guide wires of different thicknesses can be detachably fixed in the fixing straps of different inverted bow shapes.

3. The calibration device for the clamp current sensor according to claim 1, characterized in that: The bracket is provided with a groove, and the carrier back plate can be removed and placed in the groove.

4. The calibration device for the clamp current sensor according to claim 1, characterized in that: The outer diameter of the centering wheel, the outer diameter of the eccentric wheel and the inner diameter of the magnetic ring of the corresponding clamp-type current sensor match; the inner diameter of the centering wheel, the inner diameter of the eccentric wheel and the outer diameter of the corresponding guide wire match.

5. The calibration device for the clamp current sensor according to claim 1, characterized in that: The bracket is made of metal or plastic, and the carrier back plate, fixing strap, centering wheel and eccentric wheel are made of plastic.

6. The calibration device for the clamp current sensor according to claim 1, characterized in that: During calibration, the two ends of the guide wire are connected to an electronic load and a current source respectively, the clamp current sensor to be calibrated is fixed on the corresponding centering wheel or eccentric wheel on the guide wire, and the clamp current sensor to be calibrated is connected to a data acquisition device and an excitation voltage source.

7. A method for calibrating a clamp current sensor using the calibration device of any one of claims 1 to 6, characterized in that: The steps include: Step 1, the electronic load and the current source are respectively connected to the two ends of the corresponding guide wire, and a loop is formed between the current source, the calibration device, and the electronic load; the clamp current sensor to be calibrated is fixed on the corresponding centering wheel on the guide wire, and the clamp current sensor to be calibrated is connected to the data acquisition device and the excitation voltage source; Step 2, the electronic load is connected to the PC end, and the PC end is used to control the electronic load to provide an input current signal to the clamp current sensor to be calibrated, and the indication of the electronic load is fed back to the PC end; the excitation voltage source is connected to the PC end, and the PC end is used to control the excitation voltage source to provide an excitation voltage to the clamp current sensor to be calibrated; the data collector is connected to the PC end, and the PC end is used to control the data collector to collect the output signal of the clamp current sensor to be calibrated, and the data collector feeds the collected data back to the PC end; set parameters on the PC end, including the model, serial number, calibration range, and excitation voltage of the clamp current sensor to be calibrated; Step 3: Turn on the excitation voltage source, electronic load, and current source; Step 4. The PC end divides the calibration into N calibration points according to the calibration range of the clamp current sensor to be calibrated, controls the electronic load to input current from 0 to N and then to 0 calibration points, controls the data acquisition device to start recording the current output voltage signal value of the clamp current sensor when the input current and output signal are stable, and feeds back the input current value and the output voltage signal value to the PC end interface, forming a coordinate system with x and y as the current and voltage as the two-dimensional arrays, which can be displayed in real time on the interface, thereby completing a calibration process for the forward and reverse travel of the clamp current sensor; After repeating this calibration process several times, x and y are averaged; Step 5: After the calibration is completed, the PC controls to turn off the current source, electronic load, and excitation voltage source; Step 6. Then select the parameters to be displayed on the PC interface, including zero output, full scale output, sensitivity, and nonlinearity; Step 7. After obtaining the above parameters, compare them with the calibration requirements. If they meet the requirements, choose to output the Excel report, so that a complete calibration report can be generated; if there are any problems, recalibrate or repair the clamp current sensor.

8. The calibration method according to the calibration device of the clamp current sensor according to claim 7, characterized in that: Step 4: After repeating this calibration process 2-3 times, average x and y.

9. The calibration method according to the calibration device of the clamp current sensor according to claim 7, characterized in that: The data logger model is NIPCI 6154.

10. The calibration method of the clamp current sensor calibration device according to claim 7, characterized in that: When the uniformity of the magnetic field strength inside the magnetic ring of the clamp current sensor needs to be calibrated, fix the clamp current sensor on the corresponding eccentric wheel on the guide wire, and follow the above steps to obtain the parameters of the magnetic ring of the clamp current sensor in different directions, including zero point output, full scale output, sensitivity, and nonlinearity.

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