Current measuring device

Abstract

The invention relates to a current measuring device. The current measuring device comprises a power interface, a sampling resistor module, a current transmitting module, a Hall effect current sensing module, a giant magnetoresistance effect current sensing module, a tunnel magnetoresistance effect measuring module and a fluxgate current sensor module. The current measuring device is connected with an external power supply through the power interface. By adopting the method, the requirement of comprehensively comparing different current detection methods in teaching requirements can be met.

Description

Technical Field

[0001] The present application relates to the field of measurement technology, and in particular to a current measuring device. Background Art

[0002] In today's rapidly developing technological environment, current detection, as a basic component of electronic technology, plays a key role in various engineering applications and scientific research fields. However, traditional current detection experimental devices have a series of limitations, including large size, cumbersome use process and lack of adaptability, especially for users to apply current detection technology for training in actual projects, which faces considerable challenges.

[0003] At present, several current measuring devices such as portable resistance current detector, multimeter for current detection experiment with high safety and multifunctional ammeter for physical experiments have been proposed to efficiently train users on the mastery of current detection technology.

[0004] However, the above method cannot meet the requirements of comprehensive comparison of different current detection methods in teaching needs. Summary of the invention

[0005] Based on this, it is necessary to provide a current measuring device that can comprehensively compare different current detection methods to meet teaching needs in response to the above technical problems.

[0006] In a first aspect, the present application provides a current measuring device, comprising:

[0007] Power supply interface, sampling resistor module, current transmitter module, Hall effect current sensor module, giant magnetoresistance effect current sensor module, tunnel magnetoresistance effect measurement module and fluxgate current sensor module; the current measuring device is connected to the external power supply through the power supply interface;

[0008] The sampling resistor module is used to form an ohmic circuit, and a first measuring terminal is provided on the ohmic circuit; the first measuring terminal is used to provide a test port for the user to test the first current signal of the branch on the ohmic circuit;

[0009] The current transmitter module is used to form a current conversion circuit, and a second test terminal is provided on the current conversion circuit; the second test terminal is used to provide a test port for the user to test the second current signal of the branch on the current conversion circuit;

[0010] A Hall effect current sensing module is used to form a Hall circuit, and a third test terminal is provided on the Hall circuit; the third test terminal is used to provide a signal port for the user to test the third current signal of the branch on the Hall circuit;

[0011] A giant magnetoresistance effect current sensing module is used to form a giant magnetoresistance circuit, and a fourth test terminal is provided on the giant magnetoresistance circuit; the fourth test terminal is used to provide a signal port for users to test a fourth current signal of a branch on the giant magnetoresistance circuit;

[0012] A tunnel magnetoresistance effect measurement module is used to form a tunnel magnetoresistance circuit, and a fifth test terminal is provided on the tunnel magnetoresistance circuit; the fifth test terminal is used to provide a signal port for the user to test the fifth current signal of the branch on the tunnel magnetoresistance circuit;

[0013] The fluxgate current sensor module is used to form a fluxgate circuit and is provided with a sixth test terminal on the fluxgate circuit; the sixth test terminal is used to provide a signal port for users to test the sixth current signal of the branch on the fluxgate circuit.

[0014] In one embodiment, the sampling resistor module includes a resistor component, a socket component, a resistor access terminal, a resistor output terminal, a chip access terminal, and a chip output terminal;

[0015] The resistor assembly is connected to the resistor input terminal and the resistor output terminal respectively;

[0016] The socket assembly is connected to the chip input terminal and the chip output terminal respectively;

[0017] A socket assembly is used to amplify the current signal output by the current measuring device.

[0018] In one embodiment, the resistor assembly includes a plurality of first resistor elements with different resistance values;

[0019] The socket assembly includes a chip socket assembly and a resistor pin assembly. The chip socket assembly is used to connect chips of different packaging forms, and the resistor pin assembly is used to connect second resistor elements with different resistance values; the second resistor element is used to cooperate with the chip to output a current signal that meets the requirements.

[0020] In one embodiment, the current transmitter module includes a resistor access terminal, a first power access terminal, a first ground terminal and a current transmitter;

[0021] The current transmitter includes an input signal isolation circuit, a current conversion circuit and an output circuit.

[0022] In one embodiment, the model of the current transmitter is SIN-SDJI-5A, the current measurement range of the current transmitter is 0-5A, the output current range of the current transmitter is 4-20mA, and the working power supply of the current transmitter is 24VDC.

[0023] In one embodiment, the Hall effect current sensor module comprises a sensor chip, a first voltage output terminal, a second power supply access terminal, a second ground terminal and a measured circuit access interface;

[0024] The model of the sensor chip is ACS712, the current measurement range of the sensor chip is ±5A, and the frequency range of the sensor chip is 0-80kHz.

[0025] In one embodiment, the giant magnetoresistance effect current sensor module comprises a giant magnetoresistance chip, a third power supply access terminal, a third ground terminal, a current output terminal, a second voltage output terminal and a measured circuit access interface;

[0026] The giant magnetoresistance chip is an ACS70331 chip, the current detection range of the giant magnetoresistance chip is ±2.5A, the frequency range of the giant magnetoresistance chip is 0-1MHz, the operating temperature range of the giant magnetoresistance chip is -20°C - 85°C, and the sensitivity of the giant magnetoresistance chip is 200mV / A.

[0027] In one embodiment, the tunnel magnetoresistance effect measurement module includes a fourth power supply access terminal, a fourth ground terminal, a third voltage output terminal and a plurality of first current sensors with different measuring ranges;

[0028] The first current sensor includes a current through-hole, and the current through-hole is used to penetrate the object to be measured;

[0029] The model of the first current sensor is TMR7401 current sensor, the power supply voltage of the first current sensor is 5V, and the rated output voltage of the first current sensor is 3.7V.

[0030] In one of the embodiments, the fluxgate current sensor module comprises a measured current input terminal, a measured current output terminal, a fifth power supply access terminal, a fifth ground terminal, a fourth voltage output terminal and a plurality of second current sensors with different measuring ranges;

[0031] The current and voltage relationships corresponding to the second current sensors with different ranges are different.

[0032] In one embodiment, the power interface, sampling resistor module, current transmitter module, Hall effect current sensor module, giant magnetoresistance effect current sensor module, tunnel magnetoresistance effect measurement module and fluxgate current sensor module all support a variety of different connection methods.

[0033] The above-mentioned current measuring device includes: a power interface, a sampling resistor module, a current transmission module, a Hall effect current sensing module, a giant magnetoresistance effect current sensing module, a tunnel magnetoresistance effect measurement module and a fluxgate current sensor module; the current measuring device is connected to an external power supply through the power interface; the sampling resistor module is used to form an ohmic circuit, and a first measuring terminal is provided on the ohmic circuit; the first measuring terminal is used to provide a user with a test port for testing a first current signal of a branch on the ohmic circuit; the current transmission module is used to form a current conversion circuit, and a second test terminal is provided on the current conversion circuit; the second test terminal is used to provide a user with a test port for testing a second current signal of a branch on the current conversion circuit; the Hall effect current sensing module is used to form a Hall circuit, and a third test terminal is provided on the Hall circuit Terminal; the third test terminal is used to provide the user with a signal port for testing the third current signal of the branch on the Hall circuit; the giant magnetoresistance effect current sensing module is used to form a giant magnetoresistance circuit, and a fourth test terminal is provided on the giant magnetoresistance circuit; the fourth test terminal is used to provide the user with a signal port for testing the fourth current signal of the branch on the giant magnetoresistance circuit; the tunnel magnetoresistance effect measurement module is used to form a tunnel magnetoresistance circuit, and a fifth test terminal is provided on the tunnel magnetoresistance circuit; the fifth test terminal is used to provide the user with a signal port for testing the fifth current signal of the branch on the tunnel magnetoresistance circuit; the fluxgate current sensor module is used to form a fluxgate circuit, and a sixth test terminal is provided on the fluxgate circuit; the sixth test terminal is used to provide the user with a signal port for testing the sixth current signal of the branch on the fluxgate circuit. The above method can meet the requirements of comprehensive comparison of different current detection methods in teaching needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] FIG1 is a diagram showing an application environment of a current measuring device according to an embodiment;

[0036] FIG2 is a schematic diagram of a current measuring device in one embodiment;

[0037] FIG3 is a schematic diagram of a sampling resistor module in one embodiment;

[0038] FIG4 is a schematic diagram of a socket assembly according to one embodiment;

[0039] FIG5 is a schematic diagram of the placement of the low end of the sampling resistor in one embodiment;

[0040] FIG6 is a schematic diagram of the placement of the high end of a sampling resistor in one embodiment;

[0041] FIG7 is a schematic diagram of a current transmitter module in one embodiment;

[0042] FIG8 is a schematic diagram of a Hall effect current sensing module according to one embodiment;

[0043] FIG9 is a schematic diagram of a giant magnetoresistance effect current sensing module in one embodiment;

[0044] FIG10 is a schematic diagram of a tunnel magnetoresistance effect measurement module in one embodiment;

[0045] FIG11 is a schematic diagram of a fluxgate current sensor module in one embodiment;

[0046] FIG12 is a schematic diagram of a fluxgate current sensor module in another embodiment;

[0047] Description of reference numerals:

[0048] 01-current measurement system; 10-current measurement device; 20-external power supply;

[0049] 100-power interface; 101-sampling resistor module; 102-current transmitter module;

[0050] 103-Hall effect current sensor module; 104-Giant magnetoresistance effect current sensor module;

[0051] 104- tunnel magnetoresistance effect measurement module; 106- fluxgate current sensor module;

[0052] 1010-first measuring terminal; 1020-second measuring terminal;

[0053] 1030-third test terminal; 1040-fourth test terminal;

[0054] 1050-fifth test terminal; 1060-sixth test terminal;

[0055] 1011-resistance assembly; 1012-socket assembly; 1013-resistance access terminal;

[0056] 1014-resistance connection terminal; 1015-chip connection terminal; 1016-chip connection terminal;

[0057] 10110-first resistor element; 1012-socket assembly; 10120-chip socket assembly;

[0058] 10121-resistance pin assembly; 10122-chip; 10123-second resistance element;

[0059] 1020 resistor access terminal; 1021 - first power access terminal; 1022 - first ground terminal;

[0060] 1023-current transmitter; 10230-input signal isolation circuit; 10231-current conversion circuit; 10232-output circuit; 1030-sensor chip; 1031-first voltage output terminal;

[0061] 1032-second power supply access terminal; 1033-second ground terminal; 1034-test circuit access interface;

[0062] 1040-giant magnetoresistive chip; 1041-third power supply access terminal; 1042-third ground terminal;

[0063] 1043 - current output terminal; 1044 - second voltage output terminal; 1045 - measured circuit access interface;

[0064] 1050- fourth power supply input; 1051- fourth ground terminal; 1052- third voltage output terminal;

[0065] 1053 - a first current sensor; 1060 - a measured current input terminal; 1061 - a measured current output terminal;

[0066] 1062-fifth power supply input terminal; 1063-fifth ground terminal; 1064-fourth voltage output terminal;

[0067] 1065 - Second current sensor. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application 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 application and are not used to limit the present application.

[0069] In today's rapidly developing technological environment, current detection, as a basic component of electronic technology, plays a key role in various engineering applications and scientific research fields. However, traditional current detection experimental devices have a series of limitations, such as large size, cumbersome use process and lack of adaptability. These limitations make users face considerable challenges when training personnel on relevant current detection technology.

[0070] To avoid the above limitations, various current measuring devices have been proposed, including portable resistor current detectors, multimeters for current detection experiments with high safety, and multifunctional ammeters for physical experiments. The portable resistor current detectors make resistor current detectors more portable, while the multimeters for current detection experiments with high safety introduce safety measures such as waterproofing, electric shock prevention, and high current protection to solve safety issues in laboratories and teaching environments during current measurement. In addition, the multifunctional ammeters for physical experiments can detect data such as voltage, current, and resistance of various devices in the circuit.

[0071] However, the above current testing devices still have a common limitation, that is, they only focus on a single current detection principle and lack the integrated development of current detection methods based on different principles. This makes it impossible to meet the requirements of comprehensive comparison of different current detection methods in teaching needs. This application aims to solve this problem.

[0072] After the above introduction to the background technology of the current measuring device provided in the embodiment of the present application, the implementation environment involved in the current measuring device provided in the embodiment of the present application will be briefly described below. The current measuring device provided in the embodiment of the present application can be applied in the application environment as shown in Figure 1. Among them, the current measurement system 01 includes a current measuring device 10 and an external power supply 20. The current measuring device 10 is connected to the external power supply 20, and the user operates different current measurement components on the current measuring device 10 and uses different current measurement principles (for example, Ohm's law, Hall effect, giant magnetoresistance effect, tunnel magnetoresistance effect, fluxgate effect) to measure the corresponding current.

[0073] Those skilled in the art will understand that the structure shown in FIG. 1 is merely a block diagram of a partial structure related to the scheme of the present application, and does not constitute a limitation on the application environment to which the scheme of the present application is applied. The specific application environment may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0074] After introducing the application scenarios of the current measuring device 10 provided in the embodiment of the present application, the current measuring device 10 described in the present application is introduced in detail below. As shown in FIG2 , the battery stack simulation device 10 includes: a power interface 100, a sampling resistor module 101, a current transmitter module 102, a Hall effect current sensor module 103, a giant magnetoresistance effect current sensor module 104, a tunnel magnetoresistance effect measurement module 105 and a fluxgate current sensor module 106; the current measuring device 10 is connected to an external power supply 20 via the power interface 100;

[0075] The sampling resistor module 101 is used to form an ohmic circuit, and a first measuring terminal 1010 is provided on the ohmic circuit; the first measuring terminal 1010 is used to provide a test port for the user to test the first current signal of the branch on the ohmic circuit;

[0076] The current transmitter module 102 is used to form a current conversion circuit, and a second test terminal 1020 is provided on the current conversion circuit; the second test terminal 1020 is used to provide a test port for the user to test the second current signal of the branch on the current conversion circuit;

[0077] The Hall effect current sensing module 103 is used to form a Hall circuit, and a third test terminal 1030 is provided on the Hall circuit; the third test terminal 1030 is used to provide a signal port for the user to test the third current signal of the branch on the Hall circuit;

[0078] The giant magnetoresistance effect current sensing module 104 is used to form a giant magnetoresistance circuit, and a fourth test terminal 1040 is provided on the giant magnetoresistance circuit; the fourth test terminal 1040 is used to provide a signal port for the user to test the fourth current signal of the branch on the giant magnetoresistance circuit;

[0079] The tunnel magnetoresistance effect measurement module 105 is used to form a tunnel magnetoresistance circuit, and a fifth test terminal 1050 is provided on the tunnel magnetoresistance circuit; the fifth test terminal 1050 is used to provide a signal port for the user to test the fifth current signal of the branch on the tunnel magnetoresistance circuit;

[0080] The fluxgate current sensor module 106 is used to form a fluxgate circuit, and a sixth test terminal 1060 is provided on the fluxgate circuit; the sixth test terminal 1060 is used to provide a signal port for users to test the sixth current signal of the branch on the fluxgate circuit.

[0081] The sampling resistor module 101, the current transmitter module 102, the Hall effect current sensor module 103, the giant magnetoresistance effect current sensor module 104, the tunnel magnetoresistance effect measurement module 105 and the fluxgate current sensor module 106 are described in detail below:

[0082] First, for the sampling resistor module 101, referring to FIG. 3, the sampling resistor module 101 includes a resistor component 1011, a socket component 1012, a resistor input terminal 1013, a resistor output terminal 1014, a chip input terminal 1015, and a chip output terminal 1016;

[0083] The resistor assembly 1011 is connected to the resistor input terminal 1013 and the resistor output terminal 1014 respectively;

[0084] The socket assembly 1012 is connected to the chip input terminal 1015 and the chip output terminal 1016 respectively;

[0085] The socket assembly 1012 is used to amplify the current signal output by the current measuring device 10 .

[0086] Among them, the resistance component 1011 includes multiple first resistance elements 10110 with different resistance values. Referring to Figure 3, four first resistance elements 10110 with different resistance values ​​are shown, namely 1W1Ω, 1W10Ω, 1 / 4W1Ω, and 1 / 4W10Ω with a precision of one ten-thousandth.

[0087] Among them, referring to Figure 4, the socket assembly 1012 includes a chip socket assembly 10120 and a resistor pin assembly 10121. The chip socket assembly 10120 is used to connect chips 10122 of different packaging forms, and the resistor pin assembly 10121 is used to connect second resistor elements 10123 with different resistance values; the second resistor element 10123 is used to cooperate with the chip 10122 to output a current signal that meets the requirements.

[0088] In the embodiment of the present application, the first resistance element 10110 in the circuit is a precision resistor with a known resistance value, and the current in the first resistance element 10110 is calculated using Ohm's law by measuring the voltage on the first resistance element 10110. It should be noted that common series connection methods of the first resistance element 10110 include low-end placement and high-end placement.

[0089] Referring to FIG5 , low-end placement means that one end of the first resistor element 10110 is grounded. The advantage is that when the measuring instrument (such as the "ground" terminal of a non-isolated oscilloscope) shares a common ground with the power supply, it is convenient to directly measure the voltage on the first resistor element 10110. When using a differential operational amplifier for gain amplification, low-end placement can make the common mode voltage lower, which can reduce the cost of ordinary operational amplifiers. The disadvantage of low-end placement is that one end must be grounded and cannot be applied to any part of the circuit; the current-sense resistor introduces ground level interference or affects the load.

[0090] As shown in Figure 6, the high-end placement is that the first resistor element 10110 is not grounded and only needs to be connected in series with the circuit under test. The advantage of this method is that the position is flexible and does not affect the grounding of the original circuit. The disadvantage is that it is impossible to directly use a probe with one end grounded to measure the voltage signal on the sampling resistor; when using a differential op amp for gain amplification, the common-mode voltage requirement of the op amp is relatively high, which may lead to higher costs.

[0091] The above-mentioned sampling resistor module is equipped with 4 first resistor elements of 1W1Ω, 1W10Ω, 1 / 4W1Ω, and 1 / 4W10Ω with a precision of 1 / 10,000, which can be applied to different power / current occasions. In addition, the experimental box is also equipped with a chip socket assembly 10120 and a resistor pin assembly 10121. The chip socket assembly 10120 and the resistor pin assembly 10121 are used to design differential amplifier circuits with different parameters. The chip socket assembly 10120 can hold chips of different packaging forms, and the resistor pin assembly 10121 can hold second resistor elements 10123 of different resistance values.

[0092] Among them, the chip socket assembly 10120 can be a chip socket assembly in the form of a DIP14 package, or a chip socket assembly in the form of a DIP8 package.

[0093] 3 , the chip socket assembly 10120 is connected to the chip input terminal 1015 and the chip output terminal 1016 respectively, and is used to amplify the current signal output by the current measuring device 10 .

[0094] It should be noted that the chip input terminal 1015, the chip output terminal 1016, the resistor input terminal 1013 and the resistor output terminal 1014 all support different wiring connections and can meet a variety of different wiring requirements.

[0095] In the embodiment of the present application, the design of the sampling resistor module 101 provides the necessary hardware support for designing a resistance sampling method measurement circuit. The user can connect the first resistor element 10110 in series to the circuit in a "high-end placement" or "low-end placement" manner as needed, and then use the chip 10122 and the second resistor element 10123 reserved on the sampling resistor module 101 to implement a circuit design that meets the needs of various scenarios without the need for additional auxiliary tools such as a breadboard.

[0096] In the embodiment of the present application, when using the sampling resistor module to measure current, the measured circuit can be connected to any first resistor element 10110 according to actual needs, and the corresponding current waveform can be determined by measuring the voltage waveform of the first resistor element 10110 and the voltage waveform of the first resistor element 10110 and the resistance value corresponding to the first resistor element 10110. In addition, if the measured voltage signal of the first resistor element 10110 is too small, a chip 10122 of a suitable size can be placed on the chip socket assembly 10120 to amplify the smaller voltage signal. In other words, the structure of the above-mentioned sampling resistor module 101 provides great convenience for current measurement using a current sampling scheme.

[0097] Second, regarding the current transducer module 102, referring to FIG. 7, the current transducer module 102 includes a resistor access terminal 1020, a first power access terminal 1021, a first ground terminal 1022 and a current transducer 1023;

[0098] The current transmitter 1023 includes an input signal isolation circuit 10230 , a current conversion circuit 10231 and an output circuit 10232 .

[0099] The model of the current transmitter 1023 is SIN-SDJI-5A, the current measurement range of the current transmitter 1023 is 0-5A, the output current range of the current transmitter 1023 is 4-20mA, and the working power supply of the current transmitter 1023 is 24VDC.

[0100] In the embodiment of the present application, the current transmitter 1023 can convert a larger AC current signal into an AC current signal in the form of a 4-20mA standard signal, and provide the AC current signal in the form of a 4-20mA standard signal to a computer or a display instrument or a PLC for control. In other words, the current transmitter 1023 is a device for detecting AC current. The function of the current transmitter 1023 is to convert a larger AC current into a smaller AC current in a linear proportion for easy detection.

[0101] Among them, the current conversion circuit 10231 is the core of the current transmitter. The current conversion circuit 10231 is a precision full-wave rectifier circuit, which can convert the measured current into the corresponding output power. The current conversion circuit 10231 is characterized by simple circuit and good linearity, and its disadvantage is that the waveform distortion has a greater impact on it.

[0102] Among them, the advantages of the input signal isolation circuit 10230 include: (1) it has driving capability, and the output current is generally large; (2) low cost; (3) it does not require an auxiliary power supply when working, and is easy to use; (4) it can measure high-frequency AC signals that the Hall sensor cannot measure. The disadvantages of the input signal isolation circuit 10230 include: (1) because the output is large, secondary isolation is required for the microcontroller MCU acquisition in order to protect the device; (2) there is a phase difference between the primary and secondary sides, and when the MCU is collecting, the phase needs to be compensated in the software, which is more troublesome; (3) to measure large currents, it requires a larger volume, which affects installation.

[0103] In the embodiment of the present application, the model of the current conversion circuit 10231 is SIN-SDJI-5A, the current measurement range is 0-5A, the output current range is 4-20mA, and the accuracy is 0.5. The working power supply is 24VDC, which needs to be matched with a 250Ω resistor to convert into a voltage signal.

[0104] It should be noted that when using the current conversion circuit 10231 to measure the current, the second resistance element 10123 in the sampling resistance module 101 can be connected to achieve it, the measured current wire is inserted into the current through-hole in the direction of the arrow in the current conversion circuit 10231 in FIG. 7, and the resistance access terminal 1020 is connected to a 250Ω resistor to measure the voltage value of the resistor, and the current value of the measured circuit is determined according to the voltage value of the resistor.

[0105] It should be noted that the resistor access terminal 1020 , the first power access terminal 1021 , and the first ground terminal 1022 all support different wiring connections and can meet a variety of different wiring requirements.

[0106] Third, referring to FIG8 , the Hall effect current sensor module 103 includes a sensor chip 1030 , a first voltage output terminal 1031 , a second power supply access terminal 1032 , a second ground terminal 1033 and a measured circuit access interface 1034 ;

[0107] The model of the sensor chip 1030 is ACS712, the current measurement range of the sensor chip 1030 is ±5A, and the frequency range of the sensor chip 1030 is 0-80kHz.

[0108] It should be noted that the Hall effect refers to the situation where a small current passes through a semiconductor sheet placed in a magnetic field. Under the influence of the magnetic field, the current will be deflected, and a voltage difference will be formed on both sides of the semiconductor in the vertical direction of the current. This voltage difference is the Hall voltage. The magnitude of the Hall voltage is proportional to the strength of the magnetic field and the current passing through the semiconductor. According to the positive proportional relationship between the Hall voltage and the magnetic field strength, a current measuring device is designed to provide a constant control current. Then the magnitude of the Hall current is only affected by one factor, the magnetic field strength, and the change in the Hall voltage can reflect the change in the magnetic field strength. The magnetic field is generated by the corresponding current and has a clear linkage relationship with the current. The above is the basic principle of using Hall elements to measure current intensity.

[0109] The characteristic of the Hall sensor is that it can measure DC-200kHz AC and DC currents, which is different from the current transmitter module 102. The current transmitter module 102 cannot measure DC current but can only measure AC current.

[0110] In the embodiment of the present application, the Hall element chip model selected by the sensor chip 1030 is ACS712, which is an integrated linear current sensor chip based on the Hall effect, which can provide an economical and accurate solution. The sensor chip 1030 is powered by a 5V power supply, the current measurement range is ±5A, the accuracy is 1.5, and the frequency range is 0-80kHz. The output of the sensor chip 1030 model ACS712 is superimposed on 0.5Vcc, and the relationship between its output voltage and current is shown in the following formula (1):

[0111]

[0112] In the embodiment of the present application, referring to FIG8 , when the Hall effect current sensor module 103 is used to measure the current, the first voltage output terminal VCC and the second ground terminal GND are connected to the positive pole of the 5V power supply and the ground respectively, and the two measured circuit access interfaces 1034 on the right side of the sensor chip 1030 are connected in series to the measured circuit. At this time, the relationship between the voltage output by the second power access terminal 1032OUT and the current in the actual measured circuit is shown in the above formula (1). That is, by measuring the voltage at the second power access terminal OUT, the measured current value can be obtained by conversion of formula (1).

[0113] It should be noted that the first voltage output terminal 1031 , the second power supply input terminal 1032 , the second ground terminal 1033 and the measured circuit input interface 1034 all support different wiring connections and can meet a variety of different wiring requirements.

[0114] Fourth, a giant magnetoresistance effect current sensor module 104, see FIG9 , comprising a giant magnetoresistance chip 1040, a third power supply access terminal 1041, a third ground terminal 1042, a current output terminal 1043, a second voltage output terminal 1044 and a measured circuit access interface 1045;

[0115] The giant magnetoresistance chip 1040 is an ACS70331 chip. The current detection range of the giant magnetoresistance chip 1040 is ±2.5A. The frequency range of the giant magnetoresistance chip 1040 is 0-1MHz. The operating temperature range of the giant magnetoresistance chip 1040 is -20°C -85°C. The sensitivity of the giant magnetoresistance chip 1040 is 200mV / A.

[0116] The Giant Magneto Resistance (GMR) effect refers to the fact that a slight change in an external magnetic field can cause a dramatic change in the resistance of a certain multilayer film (the magnitude of the reduction in resistivity can be up to 10 times that of general magnetic materials and alloy materials). This phenomenon is very obvious in Permalloy and ferromagnetic materials. GMR sensors have been widely used in the measurement of current, magnetic field, angular displacement, acceleration, etc.

[0117] The GMR effect has a greater magnetoresistance change rate. GMR elements are more sensitive to weak magnetic fields and can accurately measure DC and AC currents. They have advantages such as small size, wide response frequency, and no residual magnetic field. The disadvantage is that the process is relatively complex and the cost is also high. They are mainly used for high-precision small current measurements. GMR sensors are more sensitive than Hall sensors and have a wider range of applications.

[0118] In the embodiment of the present application, the chip model selected for the giant magnetoresistive chip 1040 is ACS70331, which is powered by a single 3.3V power supply, has a current detection range of ±2.5A, a frequency range of 0-1MHz, and an operating temperature range of -20°C to 85°C. Its sensitivity is 200mV / A, that is, when measuring a current of 1A, the voltage at its output end is 200mV.

[0119] Referring to FIG9 , when the Hall effect current sensor module 103 is used to measure the current, the positive pole of the 3.3V external power supply and the ground are connected between the third power supply access terminal VCC and the third ground terminal, the second voltage output terminal Dout is not connected, the current output terminal Aout is the output current value, and the measured current is connected by the measured circuit access interface 1045 on the right side of FIG9 . By measuring the voltage of the current output terminal Aout, it is converted into the measured current value according to the 200mV / A sensitivity described above.

[0120] It should be noted that the third power supply input terminal 1041, the third ground terminal 1042, the current output terminal 1043, the second voltage output terminal 1044 and the measured circuit input interface 1045 all support different wiring connections and can meet a variety of different wiring requirements.

[0121] Fifth, a tunnel magnetoresistance effect measurement module 105, see FIG10, comprising a fourth power supply input 1050, a fourth ground terminal 1051, a third voltage output terminal 1052 and a plurality of first current sensors 1053 with different measuring ranges;

[0122] The first current sensor 1053 includes a current through-hole, and the current through-hole is used to penetrate the object to be measured;

[0123] The model of the first current sensor 1053 is TMR7401 current sensor, the power supply voltage of the first current sensor 1053 is 5V, and the rated output voltage of the first current sensor 1053 is 3.7V.

[0124] Among them, the tunnel magnetoresistance effect (TMR) refers to the effect that the tunnel resistance in the ferromagnetic-insulator film (about 1 nanometer)-ferromagnetic material changes with the relative direction of the ferromagnetic materials on both sides. The TMR effect is the fourth generation of magnetic sensor application technology due to its advantages such as large magnetoresistance effect and high magnetic field sensitivity. TMR sensors have the advantages of high precision, high sensitivity, low power consumption, small size, good temperature stability, and wide operating temperature range.

[0125] In the embodiment of the present application, two ranges of the first current sensor 1053 are included, namely, the first current sensor 1053 of 300mA range and the first current sensor 1053 of 600mA range. For the first current sensor 1053 of 300mA range, the output voltage With the measured current Satisfies the following formula (2):

[0126]

[0127] For the first current sensor 1053 with a range of 600 mA, the output voltage With the measured current Satisfies the following formula (3):

[0128]

[0129] In the embodiment of the present application, referring to FIG. 10 , the measured current passes through the current through-hole in the first current sensor 1053 in the direction of the current “I” in the figure, and the “+5V” and “GND” are respectively connected to the positive pole of the +5V power supply and the ground, and the voltage at “Vout” is measured. The current value can be obtained according to the conversion relationship shown in formula (2) or (3) (depending on whether the first current sensor with a range of 300mA or the first current sensor with a range of 600mA is selected).

[0130] It should be noted that the fourth power supply input 1050, the fourth ground terminal 1051, and the third voltage output terminal 1052 all support different wiring connections and can meet a variety of different wiring requirements.

[0131] Sixth, the fluxgate current sensor module 106, see FIG11, includes a measured current input terminal 1060, a measured current output terminal 1061, a fifth power supply access terminal 1062, a fifth ground terminal 1063, a fourth voltage output terminal 1064 and a plurality of second current sensors 1065 with different ranges;

[0132] The second current sensors 1065 with different ranges correspond to different current and voltage relationships.

[0133] Among them, the fluxgate principle refers to the fact that the inductance of a saturable magnetic core changes with the magnitude of the excitation current under the action of the excitation current, and the change in inductance causes the change in magnetic flux. The magnetic flux is opened or closed like a door, so it is vividly called the fluxgate principle. The characteristics of the fluxgate principle are that the upper limit of the current can be very large, and it is less affected by temperature, has low heat generation, and high precision. Its measurement accuracy is much higher than that of ordinary Hall sensors. Because the fluxgate probe is based on magnetic materials, it has a much more stable temperature characteristic than the Hall principle. The disadvantage of the fluxgate is that the internal circuit is relatively susceptible to interference from the external magnetic field.

[0134] As shown in FIG11 , the fluxgate current sensor module 106 is equipped with four types of second current sensors 1065 based on fluxgate technology, namely CAFR-6A, CAFR-15A, HIT30 and RIT02M (only CAFR-6A and CAFR-15A are shown in FIG11 ). They adopt excitation closed-loop control technology, which eliminates the complex magnetic shielding system design compared with traditional solutions, and also adopts self-excitation demagnetization technology, with small zero drift and expanded range width. Among them, the second current sensor 1065 of the CAFR series has a power supply voltage of 5V, and the current measurement range is ±20A (CAFR-6A) and ±50A (CAFR-15A), respectively, with an accuracy of 0.8% and a frequency range of 0-300kHz.

[0135] The relationship between the output voltage Vout and the measured current I of the second current sensor 1065 of CAFR-6A is shown in the following formula (4), and the relationship between the output voltage Vout and the measured current I of the second current sensor 1065 of CAFR-15A is shown in the following formula (5):

[0136]

[0137]

[0138] Among them, the second current sensor 1065 of HIT30 is powered by ±15V, the current measurement range is ±30A, the accuracy is 0.5%, and the frequency range is 0-100kHz. The relationship between the measured current I and the voltage Vout across the resistor of the second current sensor 1065 of HIT30 is shown in the following formula (6):

[0139]

[0140] Among them, the second current sensor 1065 of RIT02M is powered by ±15V, the current measurement range is ±0.2A, the accuracy is 0.2%, and the frequency range is 0-100kHz. The relationship between the measured current I and the voltage Vout across the resistor of the second current sensor 1065 of RIT02M is shown in the following formula (7):

[0141]

[0142] It should be noted that the measured current input terminal 1060, the measured current output terminal 1061, the fifth power supply input terminal 1062, the fifth ground terminal 1063, and the fourth voltage output terminal 1064 all support different wiring connections and can meet a variety of different wiring requirements.

[0143] In the embodiment of the present application, referring to FIG. 11 , taking the second current sensor 1065 of CAFR-6A as an example, the three measured current input terminals 1060 on the top of the chip CAFR-6A (these three terminals are interconnected, i.e., at the same potential, and three are provided to increase the current carrying capacity), and the three measured current output terminals 1061 on the bottom (these three terminals are interconnected, i.e., at the same potential, and three are provided to increase the current carrying capacity), the "+5V" and "0" on the experimental box are connected to the positive pole of the external 5V power supply and the ground, and the voltage of "Vout" relative to "Ref" is measured, and it can be converted into a current value according to the above formula (4) or formula (5).

[0144] It should be noted that the enlarged view of the second current sensor 1065 of HIT30 and the second current sensor 1065 of RIT02M is shown in FIG12 , wherein the direction of “I” is the direction through which the measured current passes, wherein “V+” and “V-” are respectively connected to the positive and negative poles of the ±15V power supply, and the voltage of “OUT” relative to “GND” is measured. The current value can be obtained according to the conversion formula of the above formula (6) or formula (7).

[0145] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0146] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A current measuring device, characterized in that: The current measuring device comprises: a power supply interface, a sampling resistor module, a current transmitter module, a Hall effect current sensor module, a giant magnetoresistance effect current sensor module, a tunnel magnetoresistance effect measurement module and a fluxgate current sensor module; the current measuring device is connected to an external power supply through the power supply interface; The sampling resistor module is used to form an ohmic circuit, and a first measuring terminal is provided on the ohmic circuit; the first measuring terminal is used to provide a test port for the user to test the first current signal of the branch on the ohmic circuit; The current transmitter module is used to form a current conversion circuit, and a second test terminal is provided on the current conversion circuit; the second test terminal is used to provide the user with a test port for testing a second current signal of a branch on the current conversion circuit; The Hall effect current sensing module is used to form a Hall circuit, and a third test terminal is provided on the Hall circuit; the third test terminal is used to provide the user with a signal port for testing a third current signal of a branch on the Hall circuit; The giant magnetoresistance effect current sensing module is used to form a giant magnetoresistance circuit, and a fourth test terminal is provided on the giant magnetoresistance circuit; the fourth test terminal is used to provide the user with a signal port for testing a fourth current signal of a branch on the giant magnetoresistance circuit; The tunnel magnetoresistance effect measurement module is used to form a tunnel magnetoresistance circuit, and a fifth test terminal is provided on the tunnel magnetoresistance circuit; the fifth test terminal is used to provide the user with a signal port for testing a fifth current signal of a branch on the tunnel magnetoresistance circuit; The fluxgate current sensor module is used to form a fluxgate circuit, and a sixth test terminal is provided on the fluxgate circuit; the sixth test terminal is used to provide the user with a signal port for testing a sixth current signal of a branch on the fluxgate circuit.

2. The current measuring device according to claim 1, characterized in that: The sampling resistor module includes a resistor component, a socket component, a resistor access terminal, a resistor output terminal, a chip access terminal and a chip output terminal; The resistor assembly is connected to the resistor input terminal and the resistor output terminal respectively; The socket assembly is connected to the chip input terminal and the chip output terminal respectively; The socket assembly is used to amplify the current signal output by the current measuring device.

3. The current measuring device according to claim 2, characterized in that: The resistor assembly includes a plurality of first resistor elements with different resistance values; The socket assembly includes a chip socket assembly and a resistor pin assembly. The chip socket assembly is used to connect chips of different packaging forms, and the resistor pin assembly is used to connect a second resistor element with different resistance values; the second resistor element is used to cooperate with the chip to output a current signal that meets the requirements.

4. The current measuring device according to claim 1, characterized in that: The current transmitter module includes a resistor access terminal, a first power access terminal, a first ground terminal and a current transmitter; The current transmitter comprises an input signal isolation circuit, a current conversion circuit and an output circuit.

5. The current measuring device according to claim 4, characterized in that: The model of the current transmitter is SIN-SDJI-5A, the current measurement range of the current transmitter is 0-5A, the output current range of the current transmitter is 4-20mA, and the working power supply of the current transmitter is 24VDC.

6. The current measuring device according to claim 1, characterized in that: The Hall effect current sensing module comprises a sensor chip, a first voltage output terminal, a second power supply access terminal, a second ground terminal and a measured circuit access interface; The model of the sensor chip is ACS712, the current measurement range of the sensor chip is ±5A, and the frequency range of the sensor chip is 0-80kHz.

7. The current measuring device according to claim 1, characterized in that: The giant magnetoresistance effect current sensing module comprises a giant magnetoresistance chip, a third power supply access terminal, a third ground terminal, a current output terminal, a second voltage output terminal and a measured circuit access interface; The giant magnetoresistance chip is an ACS70331 chip, the current detection range of the giant magnetoresistance chip is ±2.5A, the frequency range of the giant magnetoresistance chip is 0-1MHz, the operating temperature range of the giant magnetoresistance chip is -20°C - 85°C, and the sensitivity of the giant magnetoresistance chip is 200mV / A.

8. The current measuring device according to claim 1, characterized in that: The tunnel magnetoresistance effect measurement module includes a fourth power supply access terminal, a fourth ground terminal, a third voltage output terminal and a plurality of first current sensors with different measuring ranges; The first current sensor comprises a current through-hole, and the current through-hole is used to penetrate the object to be measured; The model of the first current sensor is TMR7401 current sensor, the power supply voltage of the first current sensor is 5V, and the rated output voltage of the first current sensor is 3.7V.

9. The current measuring device according to claim 1, characterized in that: The fluxgate current sensor module comprises a measured current input terminal, a measured current output terminal, a fifth power supply access terminal, a fifth ground terminal, a fourth voltage output terminal and a plurality of second current sensors with different measuring ranges; The current and voltage relationships corresponding to the second current sensors with different ranges are different.

10. The current measuring device according to any one of claims 1 to 9, characterized in that: The power interface, the sampling resistor module, the current transmitter module, the Hall effect current sensor module, the giant magnetoresistance effect current sensor module, the tunnel magnetoresistance effect measurement module and the fluxgate current sensor module all support a variety of different connection methods.

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