Calibration device for measuring switches

Abstract

The present application relates to the technical field of measuring switches, and in particular to a calibration device for measuring switches, comprising a standard current signal generating module, a standard voltage signal generating module and a control module. The standard current signal generating module sends a standard current signal to a measuring unit, and the standard voltage signal generating module sends a standard voltage signal to the measuring unit. The measuring unit generates an actual measurement result according to the standard current signal and the standard voltage signal, and performs calibration according to the actual measurement result and the standard measurement result sent by the control module. The calibration device can calibrate the measuring switch without a large current calibration platform, thereby improving the calibration reliability and efficiency, and also reducing the cost.

Description

Technical Field

[0001] The present application relates to the technical field of measuring switches, and in particular to a calibration device for measuring switches. Background Art

[0002] Measuring switches, used within electricity meter boxes, provide high-precision metering capabilities and require calibration during production to achieve the required accuracy. Currently, calibration techniques typically involve whole-unit calibration. Because measuring switches have high rated currents, ranging from 125A to 250A, calibration requires a calibration platform capable of providing high currents. However, such high-current calibration platforms have a short current stabilization time, resulting in low calibration efficiency.

[0003] Patent publication number CN115598583A discloses a calibration method for an intelligent measuring switch. The method includes obtaining the measuring range of the intelligent measuring switch; powering the intelligent measuring switch with a standard power supply and setting a standard voltage; sequentially adjusting the standard current output by the standard power supply to calculate the standard electrical quantities and corresponding measured electrical quantities at different standard currents; calculating the error between the standard electrical quantities and the measured electrical quantities; and calibrating the measured electrical quantities of the intelligent measuring switch based on multiple sets of error values ​​and corresponding measured electrical quantities. This method sets the calibration current to an integer value between 1% and 10% of the rated current of the intelligent measuring switch, reducing the current source capacity requirement during calibration, thereby simplifying the configuration of the calibration equipment and improving the operability and flexibility of the calibration.

[0004] However, the calibration current of this calibration method is much lower than the actual working current. This method may result in a large deviation between the measured electrical quantity obtained by calibration at a lower current level and the measured electrical quantity of the measuring switch under actual high current working conditions, which in turn affects the accuracy and reliability of the calibration. As a result, the calibrated smart measuring switch may not meet the expected high-precision measurement requirements in actual applications. Summary of the Invention

[0005] Therefore, it is necessary to provide a calibration device for a measuring switch to address the problem that the existing calibration method for a measuring switch has low accuracy and reliability.

[0006] The present invention provides a calibration device for a measuring switch, comprising a standard current signal generating module, a standard voltage signal generating module, and a control module; a first end of the standard voltage signal generating module is connected to a power supply module, a second end of the standard voltage signal generating module and a first end of the standard current signal generating module are both connected to a first end of the control module, a second end of the standard current signal generating module and a third end of the standard voltage signal generating module are both connected to a first end of a measuring unit, and a second end of the control module is connected to a second end of the measuring unit;

[0007] The control module sends an analog voltage signal to the standard current signal generating module, and the standard current signal generating module generates a standard current signal according to the analog voltage signal and sends the standard current signal to the measuring unit;

[0008] The control module generates a voltage control signal according to the voltage signal output by the standard voltage signal generating module, and sends the voltage control signal to the standard voltage signal generating module; the standard voltage signal generating module generates a standard voltage signal according to the voltage control signal, and sends the standard voltage signal to the measuring unit;

[0009] The control module sends the standard measurement result to the measurement unit. The measurement unit generates an actual measurement result according to the standard current signal and the standard voltage signal, and performs calibration according to the standard measurement result and the actual measurement result.

[0010] In one embodiment, the standard current signal generating module includes a phase A current generating unit, a phase B current generating unit and a phase C current generating unit, and the standard voltage signal generating module includes a phase A voltage generating unit, a phase B voltage generating unit and a phase C voltage generating unit; the first end of the phase A current generating unit, the first end of the phase B current generating unit and the first end of the phase C current generating unit are all connected to the first end of the control module, and the second end of the phase A current generating unit, the second end of the phase B current generating unit and the second end of the phase C current generating unit are all connected to the first end of the measurement unit; the first end of the phase A voltage generating unit, the first end of the phase B voltage generating unit and the first end of the phase C voltage generating unit are all connected to the power supply module, the second end of the phase A voltage generating unit, the second end of the phase B voltage generating unit and the second end of the phase C voltage generating unit are all connected to the first end of the control module, and the third end of the phase A voltage generating unit, the third end of the phase B voltage generating unit and the third end of the phase C voltage generating unit are all connected to the first end of the measurement unit.

[0011] In one embodiment, the A-phase current generating unit, the B-phase current generating unit, and the C-phase current generating unit each include a voltage amplifying circuit, a voltage-current conversion circuit, and a current conversion circuit; a first end of the control module is connected to a first end of the voltage amplifying circuit, a second end of the voltage amplifying circuit is connected to a first end of the voltage-current conversion circuit, a second end of the voltage-current conversion circuit is connected to a first end of the current conversion circuit, and a second end of the current conversion circuit is connected to a first end of the measuring unit;

[0012] The voltage amplifier circuit amplifies the analog voltage signal sent by the control module and sends it to the voltage-current conversion circuit. The voltage-current conversion circuit converts the amplified analog voltage signal into an analog current signal and sends it to the current conversion circuit. The current conversion circuit converts the analog current signal into a standard current signal and sends it to the measurement unit.

[0013] In one embodiment, the voltage-to-current conversion circuit includes a switch tube V1 and a resistor R1, wherein the control end of the switch tube V1 is connected to the second end of the voltage amplification circuit, the first end of the switch tube V1 is connected to the first end of the current conversion circuit, the second end of the switch tube V1 is connected to the first end of the resistor R1, and the second end of the resistor R1 is grounded.

[0014] In one embodiment, the voltage amplification circuit includes an operational amplifier U1, the non-inverting input terminal of the operational amplifier U1 is connected to the first terminal of the control module, the output terminal of the operational amplifier U1 is connected to the control terminal of the switch tube V1, and the inverting input terminal of the operational amplifier U1 is connected to the second terminal of the switch tube V1.

[0015] In one embodiment, the current conversion circuit includes a current converter CT1 and a bipolar TVS tube Z1. The first end of the input side of the current converter CT1 is connected to the second end of the voltage-current conversion circuit, the second end of the input side of the current converter CT1 is connected to a voltage source, the first port IA+ of the output side of the current converter CT1 and the first end of the bipolar TVS tube Z1 are both connected to the positive current input end of the measurement unit, and the second port IA- of the output side of the current converter CT1 and the second end of the bipolar TVS tube Z1 are both connected to the negative current input end of the measurement unit.

[0016] In one embodiment, the A-phase voltage generating unit, the B-phase voltage generating unit, and the C-phase voltage generating unit each include a voltage generating circuit and an output voltage feedback circuit, a first end of the voltage generating circuit is connected to the power module, a second end of the voltage generating circuit is connected to the first end of the measuring unit, a first end of the output voltage feedback circuit is connected to the second end of the voltage generating circuit, and a second end of the output voltage feedback circuit is connected to the first end of the control module;

[0017] The output voltage feedback circuit collects the voltage signal output by the voltage generating circuit and sends the voltage signal to the control module. The control module generates a voltage control signal based on the voltage signal and sends the voltage control signal to the voltage generating circuit. The voltage generating circuit generates a standard voltage signal based on the voltage control signal.

[0018] In one embodiment, the voltage generating circuit includes a switch tube Z2, a switch tube Z3, a switch tube Z4, a switch tube Z5, an inductor L1, an inductor L2, and a transformer T1; the control ends of the switch tubes Z2, Z3, Z4, and Z5 are all connected to the first end of the control module, the first end of the switch tube Z2 and the first end of the switch tube Z3 are both connected to the first end of the power module, the second end of the switch tube Z2 is connected to the first end of the switch tube Z4, the second end of the switch tube Z3 is connected to the first end of the switch tube Z5, the second end of the switch tube Z4 and the second end of the switch tube Z5 are both connected to the second end of the power module, the second end of the switch tube Z2 and the second end of the switch tube Z3 are both connected to the first end of the inductor L1, the second end of the inductor L1 is connected to the first end of the input side of the transformer T1, the first end of the inductor L2 is connected to the second end of the switch tube Z3, the second end of the inductor L2 is connected to the second end of the input side of the transformer T1, and the output side of the transformer T1 is connected to the voltage input end of the measurement unit.

[0019] In one embodiment, the output voltage feedback circuit includes a resistor R6, a voltage transformer PT1, a resistor R4, a resistor R2, a resistor R5, a resistor R3 and an operational amplifier U2; the first end of the resistor R6 is connected to the first output end of the voltage generating circuit, the second end of the resistor R6 is connected to the first end of the input side of the voltage transformer PT1, the second end of the input side of PT1 is connected to the second output end of the voltage generating circuit, the first end of the resistor R2 and the first end of the resistor R4 are both connected to the first end of the output side of PT1, the first end of the resistor R5 and the second end of the resistor R4 are both connected to the second end of the output side of PT1, the second end of the resistor R5 and the inverting input end of the operational amplifier U2 are both connected to the reference potential point, the second end of the resistor R2 and the first end of the resistor R3 are both connected to the non-inverting input end of the operational amplifier U2, and the second end of the resistor R3 and the first end of the control module are both connected to the output end of the operational amplifier U2.

[0020] In one embodiment, the control module includes a PC host computer, an MCU, an analog-to-digital conversion unit, a digital-to-analog conversion unit, a first RS485 communication unit, and a second RS485 communication unit. The first end of the PC host computer is connected to the first end of the first RS485 communication unit, the second end of the first RS485 communication unit is connected to the second end of the measuring unit, the second end of the PC host computer is connected to the first end of the second RS485 communication unit, the second end of the second RS485 communication unit is connected to the first end of the MCU, the second end of the MCU is connected to the first end of the digital-to-analog conversion unit, the second end of the digital-to-analog conversion unit is connected to the first end of the standard current signal generating module, the third end of the MCU is connected to the first end of the analog-to-digital conversion unit, the second end of the analog-to-digital conversion unit is connected to the second end of the standard voltage signal generating module, and the fourth end of the MCU is connected to the second end of the standard voltage signal generating module.

[0021] The PC sends a voltage output setting instruction to the MCU. The analog-to-digital conversion unit collects the voltage signal output by the standard voltage signal generation module and sends it to the MCU. The MCU generates a voltage control signal based on the voltage output setting instruction and the voltage signal output by the standard voltage signal generation module, and sends the voltage control signal to the standard voltage signal generation module.

[0022] The PC host computer sends a current output setting instruction to the MCU. The MCU generates a current output control signal according to the current output setting instruction and sends the current output control signal to the digital-to-analog conversion unit. The digital-to-analog conversion unit generates an analog voltage signal according to the current output control signal and sends the analog voltage signal to the standard current signal generation module.

[0023] The calibration device for the above-mentioned measuring switch includes a standard current signal generating module, a standard voltage signal generating module and a control module. The standard current signal generating module sends a standard current signal to the measuring unit, and the standard voltage signal generating module sends a standard voltage signal to the measuring unit. The measuring unit generates an actual measurement result based on the standard current signal and the standard voltage signal, and calibrates based on the standard measurement result and the actual measurement result sent by the control module. The calibration device can calibrate the measuring switch without a large current calibration platform, thereby improving calibration reliability and efficiency, and also reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of a calibration device for a measuring switch in one embodiment;

[0025] Figure 2 is a schematic structural diagram of a calibration device for a measuring switch in another embodiment;

[0026] Figure 3 is a schematic structural diagram of a calibration device for a measuring switch in yet another embodiment;

[0027] Figure 4 A schematic structural diagram of a calibration device for a measuring switch in yet another embodiment;

[0028] Figure 5 FIG. 1 is a schematic structural diagram of a calibration system for a measuring switch in one embodiment. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0030] The structural characteristics of the measuring switch are that the metering portion is separated from the switch body, with the metering portion located within a pluggable measuring unit. The transformer within the switch body converts the primary high-current signal into a secondary low-current signal, which is then output to the measuring unit. The transformer's transformation ratio accuracy and angular difference accuracy are fixed within a certain range, with excellent consistency. Therefore, if the measuring unit is calibrated separately, a high-current signal is not required. The calibration device for the measuring switch provided in this application is used to calibrate the measuring unit within the measuring switch. After the measuring unit is calibrated, the calibration of the measuring switch is completed by inserting the calibrated measuring unit into the switch body.

[0031] In one embodiment, Figure 1 As shown, a calibration device for a measuring switch is provided, including a standard current signal generating module 100, a standard voltage signal generating module 200 and a control module 300; the first end of the standard voltage signal generating module 200 is connected to the power module, the second end of the standard voltage signal generating module 200 and the first end of the standard current signal generating module 100 are both connected to the first end of the control module 300, the second end of the standard current signal generating module 100 and the third end of the standard voltage signal generating module 200 are both connected to the first end of the measuring unit, and the second end of the control module 300 is connected to the second end of the measuring unit.

[0032] The control module 300 sends the analog voltage signal to the standard current signal generating module 100 . The standard current signal generating module 100 generates a standard current signal according to the analog voltage signal and sends the standard current signal to the measuring unit.

[0033] The standard current signal is used to simulate the current conditions that the measurement unit may encounter during actual operation, thereby calibrating the measurement unit. The analog voltage signal is a sinusoidal analog voltage signal used to control the output current of the standard current signal generating module 100. Specifically, the control module 300 can generate a corresponding analog voltage signal based on user-entered parameters or a preset measurement unit calibration algorithm and send it to the standard current signal generating module 100.

[0034] The control module 300 generates a voltage control signal according to the voltage signal output by the standard voltage signal generating module 200 and sends the voltage control signal to the standard voltage signal generating module 200; the standard voltage signal generating module 200 generates a standard voltage signal according to the voltage control signal and sends the standard voltage signal to the measuring unit.

[0035] The standard voltage signal is used to simulate voltage conditions that the measurement unit may encounter during actual operation, ensuring the accuracy of the measurement unit's voltage measurements. Specifically, the standard voltage signal generating module 200 is powered by the power module. The control module 300 uses the collected voltage signal output by the standard voltage signal generating module 200 as a feedback signal to regulate and control the output of the standard voltage signal by the standard voltage signal generating module 200.

[0036] The control module 300 sends the standard measurement result to the measurement unit. The measurement unit generates an actual measurement result according to the standard current signal and the standard voltage signal, and performs calibration according to the standard measurement result and the actual measurement result.

[0037] The standard measurement results may include, but are not limited to, voltage, current, phase angle, power, etc. Specifically, during the calibration process, the control module 300 notifies the measurement unit of the current voltage, current, phase angle, power, etc. through a communication protocol. The measurement unit measures the standard current signal and the standard voltage signal to obtain actual measurement results, and then compares the actual measurement results with the standard measurement results. If any differences exist, the measurement unit automatically adjusts its internal parameters, such as gain and offset, to reduce errors.

[0038] Furthermore, after calibration is complete, the measurement unit can provide feedback to the control module 300 regarding the calibration results, which may include measurement error and stability parameters. The control module 300 can then compare the data before and after calibration, assess whether the error is within an acceptable range, and analyze the stability of the measurement unit. Based on the analysis results, the control module 300 then evaluates whether the calibration results meet predetermined requirements or standards. If the expected requirements are not met, the control module 300 can send a verification instruction to the measurement unit. The measurement unit, in response to the verification instruction, remeasures the same standard voltage and current signals to verify the accuracy and stability of the calibration.

[0039] The calibration device for the measuring switch in this embodiment includes a standard current signal generating module 100, a standard voltage signal generating module 200, and a control module 300. The standard current signal generating module 100 sends a standard current signal to the measuring unit, and the standard voltage signal generating module 200 sends a standard voltage signal to the measuring unit. The measuring unit generates an actual measurement result based on the standard current signal and the standard voltage signal, and performs calibration based on the standard measurement result and the actual measurement result sent by the control module 300, thereby achieving calibration of the measuring unit in the measuring switch. At the same time, the calibration device does not require a large current calibration platform, which simplifies the process, reduces costs, and improves calibration efficiency and reliability.

[0040] In order to further improve the accuracy and flexibility of the calibration device, in one embodiment, as Figure 2As shown, the standard current signal generating module 100 includes an A-phase current generating unit 110, a B-phase current generating unit 120, and a C-phase current generating unit 130, and the standard voltage signal generating module 200 includes an A-phase voltage generating unit 210, a B-phase voltage generating unit 220, and a C-phase voltage generating unit 230; the first end of the A-phase current generating unit 110, the first end of the B-phase current generating unit 120, and the first end of the C-phase current generating unit 130 are all connected to the first end of the control module 300, and the second end of the A-phase current generating unit 110, the second end of the B-phase current generating unit 120, and the C-phase current generating unit 130 are connected to the first end of the control module 300. The second end of the current generating unit 130 is connected to the first end of the measuring unit; the first end of the A-phase voltage generating unit 210, the first end of the B-phase voltage generating unit 220 and the first end of the C-phase voltage generating unit 230 are all connected to the power supply module, the second end of the A-phase voltage generating unit 210, the second end of the B-phase voltage generating unit 220 and the second end of the C-phase voltage generating unit 230 are all connected to the first end of the control module 300, and the third end of the A-phase voltage generating unit 210, the third end of the B-phase voltage generating unit 220 and the third end of the C-phase voltage generating unit 230 are all connected to the first end of the measuring unit.

[0041] Among them, the standard current signal generating module 100 includes an A-phase current generating unit 110, a B-phase current generating unit 120, and a C-phase current generating unit 130. These three independent and structurally identical current generating units respectively simulate the current of each phase in the three-phase current system. The first ends of the three current generating units are connected to the control module 300 to receive the analog voltage signal from the control module 300, while their second ends are connected to the measurement unit to provide an accurate standard current signal for calibration. In addition, in order to provide a reliable calibration current signal to the measurement unit, the control module 300 controls the phase angles of the standard current signals output by the A-phase current generating unit 110, the B-phase current generating unit 120, and the C-phase current generating unit 130 to be the same.

[0042] Similarly, the standard voltage signal generating module 200 includes an A-phase voltage generating unit 210, a B-phase voltage generating unit 220, and a C-phase voltage generating unit 230. The first end of each of these voltage generating units is connected to the power supply module to obtain a stable power supply; the second end is connected to the control module 300 to receive a voltage control signal to adjust the output voltage value; and the third end is connected to the measurement unit to transmit a standard voltage signal for calibration. Similarly, the control module 300 controls the phase angle of the standard voltage signals output by the A-phase voltage generating unit 210, the B-phase voltage generating unit 220, and the C-phase voltage generating unit 230 to be the same, and also the same as the phase angle of the standard current signals output by the A-phase current generating unit 110, the B-phase current generating unit 120, and the C-phase current generating unit 130.

[0043] The calibration device in this embodiment uses the A-phase current generating unit 110 to generate a standard A-phase current signal, the B-phase current generating unit 120 to generate a standard B-phase current signal, and the C-phase current generating unit 130 to generate a standard C-phase current signal. Furthermore, the A-phase voltage generating unit 210 generates a standard A-phase voltage signal, the B-phase voltage generating unit 220 generates a standard B-phase voltage signal, and the C-phase voltage generating unit 230 generates a standard C-phase voltage signal. This allows the measurement accuracy of the measurement unit to be fully verified and calibrated in a three-phase environment. Furthermore, by independently controlling the current and voltage of each phase, the accuracy and flexibility of the calibration are further improved.

[0044] In one embodiment, Figure 3 As shown, the A-phase current generating unit 110, the B-phase current generating unit 120, and the C-phase current generating unit 130 each include a voltage amplifying circuit 111, a voltage-current conversion circuit 112, and a current conversion circuit 113; a first end of the control module 300 is connected to a first end of the voltage amplifying circuit 111, a second end of the voltage amplifying circuit 111 is connected to a first end of the voltage-current conversion circuit 112, a second end of the voltage-current conversion circuit 112 is connected to a first end of the current conversion circuit 113, and a second end of the current conversion circuit 113 is connected to a first end of the measuring unit;

[0045] The voltage amplifier circuit 111 amplifies the analog voltage signal sent by the control module 300 and sends it to the voltage-current conversion circuit 112. The voltage-current conversion circuit 112 converts the amplified analog voltage signal into an analog current signal and sends it to the current conversion circuit 113. The current conversion circuit 113 converts the analog current signal into a standard current signal and sends it to the measurement unit.

[0046] Specifically, the voltage amplifier circuit 111 is the first stage of the current generating unit, which is responsible for receiving the weak analog voltage signal from the control module 300 and amplifying it to a level suitable for subsequent circuit processing. The amplification factor can be designed according to system requirements to ensure the accuracy and stability of the signal. The amplified analog voltage signal is sent to the voltage-current conversion circuit 112. The voltage-current conversion circuit 112 usually uses the characteristics of certain components, such as MOSFET, BJT, op amp and resistor combination, to convert the input analog voltage signal into a corresponding analog current signal, and then sends the analog current signal to the current conversion circuit 113. After receiving the analog current signal, the current conversion circuit 113 converts it into a current signal that meets specific standards, such as a 0~75mA standard sinusoidal current signal to meet the current range of the measurement unit.

[0047] In this embodiment, the A-phase current generating unit 110, the B-phase current generating unit 120, and the C-phase current generating unit 130 all include a voltage amplifier circuit 111, a voltage-to-current conversion circuit 112, and a current conversion circuit 113. These circuits work together at multiple levels to achieve high-precision control of the standard current signal output, thereby significantly improving the reliability of the measurement switch calibration process. In addition, by flexibly adjusting key parameters such as the gain of the voltage amplifier circuit 111, the conversion coefficient of the voltage-to-current conversion circuit 112, and the conversion ratio of the current conversion circuit 113, the calibration device can adapt to the needs of a variety of different application scenarios and accurately calibrate different types of measurement units. At the same time, the modular design makes troubleshooting and maintenance more convenient and efficient.

[0048] In one embodiment, Figure 4 As shown, the voltage-current conversion circuit 112 includes a switch tube V1 and a resistor R1. The control end of the switch tube V1 is connected to the second end of the voltage amplifier circuit 111, the first end of the switch tube V1 is connected to the first end of the current conversion circuit 113, the second end of the switch tube V1 is connected to the first end of the resistor R1, and the second end of the resistor R1 is grounded.

[0049] The output voltage of the voltage amplifier circuit 111 can control the conduction level of the switch V1, thereby varying the current output by the switch V1. Specifically, when the output of the voltage amplifier circuit 111 changes, the conduction current of the switch V1 also changes accordingly, thereby changing the current flowing into the current conversion circuit 113. The current conversion circuit 113 then converts this current into a standard current signal and transmits it to the measurement unit.

[0050] Further, such as Figure 4 As shown in FIG, when the switch tube is a MOSFET, a body diode can be connected between its source and drain to prevent the MOS tube from burning out.

[0051] In this embodiment, the voltage-to-current conversion circuit 112 includes a switch tube V1 and a resistor R1. The conduction degree of the switch tube V1 is adjusted by the voltage output by the voltage amplifier circuit 111, so that the magnitude and accuracy of the output current can be flexibly controlled.

[0052] In one embodiment, the voltage amplification circuit 111 includes an operational amplifier U1, the non-inverting input terminal of the operational amplifier U1 is connected to the first terminal of the control module 300, the output terminal of the operational amplifier U1 is connected to the control terminal of the switch tube V1, and the inverting input terminal of the operational amplifier U1 is connected to the second terminal of the switch tube V1.

[0053] Specifically, after the non-inverting input terminal of the operational amplifier U1 obtains the analog voltage signal sent by the control module 300, its output terminal outputs the amplified analog voltage signal to the control terminal of the switch tube V1. The amplitude of the voltage signal is determined by the gain of the operational amplifier U1. When the output voltage of the operational amplifier U1 changes, the conduction current of the switch tube V1 will also change accordingly. When this current passes through the resistor R1, a voltage drop will be generated on R1. This voltage drop is fed back to the inverting input terminal of the operational amplifier U1 and compared with the voltage at the non-inverting input terminal. Through the negative feedback mechanism, the operational amplifier U1 continuously adjusts its output until the circuit reaches a stable state. Furthermore, those skilled in the art can adjust the gain of the operational amplifier U1 by designing different resistor divider networks of the operational amplifier U1 according to the actual measurement scenario to achieve calibration of measurement units of different ranges.

[0054] This embodiment uses an operational amplifier to amplify the analog voltage signal sent by the control module 300, which can effectively suppress noise and distortion, thereby improving the reliability of the standard current signal.

[0055] In one embodiment, the current conversion circuit 113 includes a current converter CT1 and a bipolar TVS transistor Z1. The first end of the input side of the current converter CT1 is connected to the second end of the voltage-current conversion circuit 112, and the second end of the input side of the current converter CT1 is connected to a voltage source. The first port IA+ on the output side of the current converter CT1 and the first end of the bipolar TVS transistor Z1 are both connected to the positive current input terminal of the measurement unit. The second port IA- on the output side of the current converter CT1 and the second end of the bipolar TVS transistor Z1 are both connected to the negative current input terminal of the measurement unit.

[0056] Among them, the first end of the measuring unit includes a positive current input end and a negative current input end, the first port IA+ on the output side of the current converter CT1 in the A-phase current generating unit 110, the B-phase current generating unit 120 and the C-phase current generating unit 130 and the first end of the bipolar TVS tube Z1 are both connected to the positive current input end of the measuring unit, and the second port IA- on the output side of the current converter CT1 and the second end of the bipolar TVS tube Z1 are both connected to the negative current input end of the measuring unit.

[0057] Specifically, the input side of current transformer CT1 is connected to a voltage source and the second terminal of voltage-to-current conversion circuit 112 to measure the current flowing out of voltage-to-current conversion circuit 112. After this current is converted by current transformer CT1, a current signal proportional to the input current is generated at the output side of current transformer CT1. A bipolar TVS diode Z1 is connected in parallel with the output side of current transformer CT1 to protect the measurement unit from transient overvoltages. When an overvoltage occurs in the circuit, the TVS diode quickly turns on, providing bidirectional overvoltage protection.

[0058] The current conversion circuit 113 in this embodiment includes a current converter CT1, which can accurately convert the current signal on the input side into a current signal that is convenient for measurement by the measurement unit, facilitating subsequent measurement by the measurement unit. In addition, by introducing a bipolar TVS diode, bidirectional overvoltage protection is provided for the current conversion circuit 113, thereby effectively preventing overvoltage damage to the measurement unit and subsequent circuits, thereby improving the reliability and stability of the entire system.

[0059] In one embodiment, Figure 3 As shown, the A-phase voltage generating unit 210, the B-phase voltage generating unit 220 and the C-phase voltage generating unit 230 all include a voltage generating circuit 211 and an output voltage feedback circuit 212, the first end of the voltage generating circuit 211 is connected to the power supply module, the second end of the voltage generating circuit 211 is connected to the first end of the measuring unit, the first end of the output voltage feedback circuit 212 is connected to the second end of the voltage generating circuit 211, and the second end of the output voltage feedback circuit 212 is connected to the first end of the control module 300.

[0060] The output voltage feedback circuit 212 collects the voltage signal output by the voltage generating circuit 211 and sends the voltage signal to the control module 300. The control module 300 generates a voltage control signal based on the voltage signal and sends the voltage control signal to the voltage generating circuit 211. The voltage generating circuit 211 generates a standard voltage signal based on the voltage control signal.

[0061] Specifically, after receiving power from the power module, the voltage generating circuit 211 generates a voltage signal based on the voltage control signal from the control module 300. The output voltage feedback circuit 212 monitors the voltage output by the voltage generating circuit 211 in real time and feeds this information back to the control module 300. The control module 300 compares the feedback voltage signal with a preset voltage target value and generates an adjusted voltage control signal. After receiving the adjusted voltage control signal, the voltage generating circuit 211 adjusts its output voltage to be consistent with the preset target value or within a predetermined accuracy range, thereby stably generating the required standard voltage signal.

[0062] The A-phase voltage generating unit 210, the B-phase voltage generating unit 220 and the C-phase voltage generating unit 230 in this embodiment can monitor and adjust the output of the voltage generating circuit 211 in real time by introducing a closed-loop control mechanism of the output voltage feedback circuit 212 and the control module 300, thereby ensuring that the output three-phase voltage signal has high precision and stability.

[0063] In one embodiment, Figure 4As shown, the voltage generating circuit 211 includes a switch tube Z2, a switch tube Z3, a switch tube Z4, a switch tube Z5, an inductor L1, an inductor L2, and a transformer T1; the control ends of the switch tubes Z2, Z3, Z4, and Z5 are all connected to the first end of the control module 300, the first end of the switch tube Z2 and the first end of the switch tube Z3 are both connected to the first end of the power module, the second end of the switch tube Z2 is connected to the first end of the switch tube Z4, the second end of the switch tube Z3 is connected to the first end of the switch tube Z5, the second end of the switch tube Z4 and the second end of the switch tube Z5 are both connected to the second end of the power module, the second end of the switch tube Z2 and the second end of the switch tube Z3 are both connected to the first end of the inductor L1, the second end of the inductor L1 is connected to the first end of the input side of the transformer T1, the first end of the inductor L2 is connected to the second end of the switch tube Z3, the second end of the inductor L2 is connected to the second end of the input side of the transformer T1, and the output side of the transformer T1 is connected to the voltage input end of the measurement unit.

[0064] The first end of the measurement unit includes a voltage input terminal, which may include a positive voltage input terminal and a negative voltage input terminal. The first output terminal of transformer T1 in phase A voltage generating unit 210, phase B voltage generating unit 220, and phase C voltage generating unit 230 can be connected to the positive voltage input terminal of the measurement unit, and the second output terminal of transformer T1 can be connected to the negative voltage input terminal of the measurement unit. The operating states of switching transistors Z2, Z3, Z4, and Z5 are uniformly controlled by control module 300. Control module 300 generates control signals for each switching transistor based on the voltage signal sent by output voltage feedback circuit 212 and a preset target value to adjust the switching state of each switching transistor, thereby controlling the output voltage. Inductors L1 and L2 are used to store and release energy to smooth the voltage waveform and assist in voltage regulation. Transformer T1 performs a voltage conversion function, converting the input electrical energy into the required voltage level within the measurement range of the measurement unit.

[0065] Specifically, when the control module 300 issues a control signal, the switches Z2, Z3, Z4, and Z5 switch according to the control signal, controlling the current flow path in the circuit. By adjusting the on-off time and frequency of the switches, the current through inductors L1 and L2 can be controlled, thereby affecting the input voltage and output voltage of transformer T1. Transformer T1 converts the input electrical energy into the required voltage level and outputs it. This output voltage is fed back to the control module 300 in real time via the output voltage feedback circuit 212. By comparing the feedback voltage with the preset target value, the control module 300 continuously adjusts the control signal until the output voltage stabilizes at the preset value or reaches a predetermined accuracy range, thereby generating the required standard voltage signal.

[0066] The voltage generation circuit 211 of this embodiment achieves highly accurate and flexible voltage output regulation through the synergistic effect of a switch control strategy, an inductor, and a transformer. The control module 300 responds to voltage feedback signals in real time, rapidly adjusting the operating state of the switch to precisely control the output voltage to a preset target value, improving the system's response speed and anti-interference capabilities.

[0067] In one embodiment, Figure 4 As shown, the output voltage feedback circuit 212 includes a resistor R6, a voltage transformer PT1, a resistor R4, a resistor R2, a resistor R5, a resistor R3 and an operational amplifier U2; the first end of the resistor R6 is connected to the first output end of the voltage generating circuit 211, the second end of the resistor R6 is connected to the first end of the input side of the voltage transformer PT1, the second end of the input side of PT1 is connected to the second output end of the voltage generating circuit 211, the first end of the resistor R2 and the first end of the resistor R4 are both connected to the first end of the output side of PT1, the first end of the resistor R5 and the second end of the resistor R4 are both connected to the second end of the output side of PT1, the second end of the resistor R5 and the inverting input end of the operational amplifier U2 are both connected to the reference potential point, the second end of the resistor R2 and the first end of the resistor R3 are both connected to the non-inverting input end of the operational amplifier U2, and the second end of the resistor R3 and the first end of the control module 300 are both connected to the output end of the operational amplifier U2.

[0068] The second end of the voltage generating circuit 211 includes a first output end and a second output end. Resistor R6 is used to sample the output voltage of the voltage generating circuit 211. The voltage transformer PT1 is used to measure and convert the voltage difference between the two output ends of the voltage generating circuit 211, converting the high voltage signal into a low voltage signal for subsequent processing. The first ends of resistors R2 and R4 are connected to the first end of the output side of PT1, forming a voltage divider network for the PT1 output voltage. The first end of resistor R5 is connected to the second end of the output side of PT1, while the second end of resistor R5 is connected to a reference potential point (such as ground). Together, R5 and R4 form another voltage divider network for generating a voltage signal related to the PT1 output voltage, which is used as a reference or comparison signal. The operational amplifier U2 amplifies the voltage difference between its inverting and non-inverting inputs. If the sampled value of the voltage signal output by the voltage generating circuit 211 is higher than the reference voltage, the operational amplifier will output a negative error voltage; otherwise, it will output a positive error voltage. The magnitude of this error voltage reflects the degree of deviation between the voltage signal output by the voltage generating circuit 211 and the expected value.

[0069] The output voltage feedback circuit 212 in this embodiment improves the stability and accuracy of the output voltage through precise voltage measurement and feedback mechanism, and enhances the anti-interference capability and dynamic performance of the calibration device.

[0070] In one embodiment, Figure 4 As shown, the control module 300 includes a PC host computer, an MCU, an analog-to-digital conversion unit, a digital-to-analog conversion unit, a first RS485 communication unit and a second RS485 communication unit. The first end of the PC host computer is connected to the first end of the first RS485 communication unit, the second end of the first RS485 communication unit is connected to the second end of the measuring unit, the second end of the PC host computer is connected to the first end of the second RS485 communication unit, the second end of the second RS485 communication unit is connected to the first end of the MCU, the second end of the MCU is connected to the first end of the digital-to-analog conversion unit, the second end of the digital-to-analog conversion unit is connected to the first end of the standard current signal generating module 100, the third end of the MCU is connected to the first end of the analog-to-digital conversion unit, the second end of the analog-to-digital conversion unit is connected to the second end of the standard voltage signal generating module 200, and the fourth end of the MCU is connected to the second end of the standard voltage signal generating module 200.

[0071] The PC host computer sends a voltage output setting instruction to the MCU, the analog-to-digital conversion unit collects the voltage signal output by the standard voltage signal generating module 200 and sends it to the MCU, the MCU generates a voltage control signal based on the voltage output setting instruction and the voltage signal output by the standard voltage signal generating module 200, and sends the voltage control signal to the standard voltage signal generating module 200; the standard voltage signal generating module 200 adjusts its output voltage according to the voltage control signal.

[0072] The PC sends a current output setting instruction to the MCU. The MCU generates a current output control signal based on the current output setting instruction and sends the current output control signal to the digital-to-analog conversion unit. The digital-to-analog conversion unit generates an analog voltage signal based on the current output control signal and sends the analog voltage signal to the standard current signal generation module 100. The standard current signal generation module 100 adjusts its output current based on the analog voltage signal.

[0073] The control module 300 in this embodiment includes a PC host computer, an MCU, an analog-to-digital conversion unit, a digital-to-analog conversion unit, a first RS485 communication unit, and a second RS485 communication unit. Through remote control and real-time data feedback from the PC host computer, the user can conveniently adjust the calibration voltage and calibration current of the measurement unit.

[0074] In order to better understand the calibration device of the measuring unit in the above embodiment, a more detailed embodiment is provided below for description.

[0075] In one embodiment, Figure 4As shown, a measurement unit calibration device is provided, including a PC host computer, a first RS485 communication unit, a second RS485 communication unit, an MCU (microcontroller unit), an ADC chip (analog-to-digital conversion unit), a DAC chip (digital-to-analog conversion unit), an A-phase current generating unit 110, a B-phase current generating unit 120, a C-phase current generating unit 130, an A-phase voltage generating unit 210, a B-phase voltage generating unit 220, a C-phase voltage generating unit 230, and a power module. The A-phase current generating unit 110, the B-phase current generating unit 120, and the C-phase current generating unit 130 have the same structure. For example, the A-phase current generating unit 110 includes an operational amplifier U1, a switch V1, a resistor R1, a current transformer CT1, and a bipolar TVS diode Z1. Phase A voltage generating unit 210, phase B voltage generating unit 220, and phase C voltage generating unit 230 have the same structure. Taking phase A voltage generating unit 210 as an example, it includes switches Z2, Z3, Z4, and Z5, inductors L1 and L2, transformer T1, resistor R6, voltage transformer PT1, resistors R4, R2, R5, and R3, and operational amplifier U2. In this embodiment, switch V1 is a MOS transistor with a body diode connected between its source and drain. Switches Z2, Z3, Z4, and Z5 are all thyristors, and filter capacitor C1 is a polarized capacitor.

[0076] The first terminal of the PC host computer is connected to the second terminal of the measurement unit via a first RS485 communication unit, and the second terminal of the PC host computer is connected to the first terminal of the MCU via a second RS485 communication unit. The MCU is connected to the DAC chip via the SPI1 interface. The DAC_IA interface of the DAC chip is connected to the non-inverting input terminal of the operational amplifier U1; the DAC_IB interface of the DAC chip is connected to the non-inverting input terminal of the operational amplifier in the B-phase current generating unit 120; and the DAC_IC interface of the DAC chip is connected to the non-inverting input terminal of the operational amplifier in the C-phase current generating unit 130.

[0077] Taking the A-phase current generating unit 110 as an example, the output end of the operational amplifier U1 is connected to the gate of the MOS tube V1, the source of the MOS tube V1 is connected to the first end of the resistor R1, the second end of the resistor R1 is grounded, the inverting input end of the operational amplifier U1 is connected to the source of the MOS tube V1, forming a feedback loop, the drain of the MOS tube V1 is connected to the first end (6) of the input side of the current converter CT1, the second end (1) of the input side of the current converter CT1 is connected to V12P0 (voltage source), the first port (4) of the output side of the current converter CT1 is connected to the first end of the bipolar TVS tube, the second port (3) of the output side of the current converter CT1 is connected to the second end of the bipolar TVS tube, the first end of the bipolar TVS tube is connected to the positive current input end of the measuring unit, and the second end of the bipolar TVS tube is connected to the negative current input end of the measuring unit. The principle of the current generating unit generating a standard current signal is as follows: the MCU is connected to the DAC chip via SPI, and controls the DAC to output an analog voltage signal of a 50Hz sinusoidal waveform, so that the current generating circuit can output an AC0~75mA standard sinusoidal current signal. At the same time, the MCU controls the phase angles of the standard current signals output by the A-phase current generating unit 110 , the B-phase current generating unit 120 , and the C-phase current generating unit 130 through the DAC chip to be 120°.

[0078] The MCU is connected to the ADC chip through the SPI2 interface. The ADC_UA interface of the ADC chip is connected to the output end of the operational amplifier U2. The ADC_UB interface is connected to the output end of the operational amplifier in the B-phase voltage generating unit 220. The ADC_UC interface is connected to the output end of the operational amplifier in the C-phase voltage generating unit 230.

[0079] The power supply module includes an AC voltage source V2, a transformer T2, a rectifier bridge D1, and a filter capacitor C1. The positive electrode of the AC voltage source V2 is connected to the first end (1) of the input side of the transformer T2, the negative electrode is connected to the second end (2) of the input side of the transformer T2, the first end (4) of the output side of the transformer T2 is connected to the first end (1) of the rectifier bridge D1, the second end (3) of the output side of the transformer T2 is connected to the second end (2) of the rectifier bridge D1, the third end (3) of the rectifier bridge D1 is connected to the positive electrode of the capacitor C1, and the fourth end (4) of the rectifier bridge D1 is connected to the negative electrode of the capacitor C1.

[0080] Taking the A-phase voltage generating unit 210 as an example, the positive electrode of the capacitor C1 is connected to the first end of the switch tube Z2 and the first end of the switch tube Z3, the negative electrode of the capacitor C1 is connected to the second end of the switch tube Z4 and the second end of the switch tube Z5, the second end of the switch tube Z2 and the second end of the switch tube Z3 are both connected to the first end of the inductor L1, the second end of the inductor L2 is connected to the first end (1) of the input side of the transformer T1, the first end of the switch tube Z4 and the first end of the switch tube Z5 are both connected to the first end of the inductor L2, and the second end of the inductor L2 is connected to the second end (2) of the input side of the transformer T1. The control end of the switch tube Z2 is connected to the CTRLA1 interface of the MCU, the control end of the switch tube Z3 is connected to the CTRLA2 interface of the MCU, the control end of the switch tube Z4 is connected to the CTRLA3 interface of the MCU, and the control end of the switch tube Z5 is connected to the CTRLA4 interface of the MCU. The first end (4) of the output side of the transformer T1 is connected to the positive voltage input end of the measurement unit, and the second end (3) of the output side of the transformer T1 is connected to the negative voltage input end of the measurement unit. The first end of the resistor R6 is connected to the first end (4) of the output side of the transformer T1, the second end of the resistor R6 is connected to the first end (4) of the input side of the voltage transformer PT1, the second end (3) of the output side of the transformer T1 is connected to the second end (3) of the input side of the voltage transformer PT1, the first ends of the resistor R2 and the resistor R4 are both connected to the first end (1) of the output side of the voltage transformer PT1, the second end of the resistor R4 and the first end of the resistor R5 are both connected to the second end (6) of the output side of the voltage transformer PT1, the second end of the resistor R2 and the first end of the resistor R3 are both connected to the non-inverting input terminal of the operational amplifier U2, the second end of the resistor R5 and the inverting input terminal of the operational amplifier U2 are both connected to the reference potential point, and the second end of the resistor R3 is connected to the output terminal of the operational amplifier U2.

[0081] The A-phase voltage generator unit 210 generates a standard voltage signal as follows: The MCU uses an IO port to output control signals (CTRLA1 to CTRLA4). These signals precisely control the on / off states of switches Z2 to Z5, thereby dynamically managing the circuitry within the voltage generator unit to generate the required AC voltage signal. This AC voltage signal is then sampled by a sampling circuit comprising voltage transformer PT1, resistors R4, R2, R5, R3, and operational amplifier U2. The MCU connects to an ADC chip via the SPI2 interface to digitally sample the voltage signal. The MCU uses the collected voltage signal characteristics as feedback signals and adjusts the output of the standard AC 0-380V voltage signal from the control unit based on these feedback signals. The B-phase and C-phase voltage generator units 230 generate standard voltage signals in the same manner as the A-phase. Furthermore, the MCU uses the ADC chip to control the output of the standard voltage signals from the A-phase, B-phase, and C-phase voltage generator units 210, 220, and 230 to maintain a phase angle of 120°.

[0082] The PC communicates with the MCU via the RS485 bus. During calibration, voltage and current output setting instructions are sent to the MCU via the communication protocol, informing the MCU to output the corresponding voltage and current signals.

[0083] The PC communicates with the measurement unit via the RS485 bus. During calibration, the measurement unit is notified of the current voltage / current / phase angle / power values ​​of the source via the communication protocol, and the measurement unit performs calibration. After calibration, the measurement unit is placed into the measurement switch body to verify accuracy.

[0084] In addition, if Figure 5 As shown, this embodiment also provides a calibration system for a measuring unit, including a calibration device for at least one measuring unit, wherein the first end of each calibration device is connected to a PC host computer, and the second end of each calibration device is connected to a different measuring unit, so that one measuring unit can be calibrated separately. Among them, each calibration device can be uniformly managed by a PC host computer, and the remaining structure is the same as the structure of the above-mentioned calibration device, including a first RS485 communication unit, a second RS485 communication unit, an MCU, an ADC chip, a DAC chip, an A-phase current generating unit 110, a B-phase current generating unit 120, a C-phase current generating unit 130, an A-phase voltage generating unit 210, a B-phase voltage generating unit 220, a C-phase voltage generating unit 230 and a power supply module. The calibration system adopts a method of connecting multiple calibration devices in parallel to realize the simultaneous calibration of multiple measuring units. The detailed calibration process can refer to the calibration process of the above-mentioned calibration device, which will not be repeated here.

[0085] The calibration device for the measurement unit in this embodiment greatly improves the calibration efficiency and reliability of the measurement switch, and is low-cost, which can greatly reduce the economic investment in calibration equipment. In addition, the calibration system for the measurement unit in this embodiment can realize the simultaneous calibration of multiple measurement units, further improving the calibration efficiency of the measurement switch.

[0086] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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 specification.

[0087] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A calibration device for a measuring switch, characterized in that: The device comprises a standard current signal generating module, a standard voltage signal generating module and a control module; the standard current signal generating module comprises an A-phase current generating unit, a B-phase current generating unit and a C-phase current generating unit, and the standard voltage signal generating module comprises an A-phase voltage generating unit, a B-phase voltage generating unit and a C-phase voltage generating unit; the A-phase current generating unit, the B-phase current generating unit and the C-phase current generating unit all comprise a voltage amplifying circuit, a voltage-current conversion circuit and a current conversion circuit; the first end of the control module is connected to the first end of the voltage amplifying circuit, the second end of the voltage amplifying circuit is connected to the first end of the voltage-current conversion circuit, the second end of the voltage-current conversion circuit is connected to the first end of the current conversion circuit, and the second end of the current conversion circuit is connected to the first end of the measuring unit; Wherein, the current conversion circuit includes a current converter CT1 and a bipolar TVS tube Z1, the first end of the input side of the current converter CT1 is connected to the second end of the voltage-current conversion circuit, the second end of the input side of the current converter CT1 is connected to a voltage source, the first port IA+ on the output side of the current converter CT1 and the first end of the bipolar TVS tube Z1 are both connected to the positive current input end of the measuring unit, and the second port IA- on the output side of the current converter CT1 and the second end of the bipolar TVS tube Z1 are both connected to the negative current input end of the measuring unit; The A-phase voltage generating unit, the B-phase voltage generating unit and the C-phase voltage generating unit each include a voltage generating circuit and an output voltage feedback circuit; a first end of the voltage generating circuit is connected to a power module, a second end of the voltage generating circuit is connected to a first end of the measuring unit, a first end of the output voltage feedback circuit is connected to a second end of the voltage generating circuit, and a second end of the output voltage feedback circuit is connected to a first end of the control module; The voltage generating circuit includes a switch tube Z2, a switch tube Z3, a switch tube Z4, a switch tube Z5, an inductor L1, an inductor L2 and a transformer T1; the control end of the switch tube Z2, the control end of the switch tube Z3, the control end of the switch tube Z4 and the control end of the switch tube Z5 are all connected to the first end of the control module, the first end of the switch tube Z2 and the first end of the switch tube Z3 are both connected to the first end of the power module, the second end of the switch tube Z2 is connected to the first end of the switch tube Z4, and the second end of the switch tube Z3 is connected to The first end of the switch tube Z5, the second end of the switch tube Z4 and the second end of the switch tube Z5 are all connected to the second end of the power module, the second end of the switch tube Z2 and the second end of the switch tube Z3 are all connected to the first end of the inductor L1, the second end of the inductor L1 is connected to the first end of the input side of the transformer T1, the first end of the inductor L2 is connected to the second end of the switch tube Z3, the second end of the inductor L2 is connected to the second end of the input side of the transformer T1, and the output side of the transformer T1 is connected to the voltage input end of the measuring unit; The output voltage feedback circuit includes a resistor R6, a voltage transformer PT1, a resistor R4, a resistor R2, a resistor R5, a resistor R3 and an operational amplifier U2; the first end of the resistor R6 is connected to the first output end of the voltage generating circuit, the second end of the resistor R6 is connected to the first end of the input side of the voltage transformer PT1, the second end of the PT1 input side is connected to the second output end of the voltage generating circuit, the first end of the resistor R2 and the first end of the resistor R4 are both connected to the first end of the output side of the PT1, the first end of the resistor R5 and the second end of the resistor R4 are both connected to the second end of the output side of the PT1, the second end of the resistor R5 and the inverting input end of the operational amplifier U2 are both connected to a reference potential point, the second end of the resistor R2 and the first end of the resistor R3 are both connected to the non-inverting input end of the operational amplifier U2, and the second end of the resistor R3 and the first end of the control module are both connected to the output end of the operational amplifier U2; The control module sends an analog voltage signal to the voltage amplifying circuit, the voltage amplifying circuit amplifies the analog voltage signal and sends it to the voltage-current conversion circuit, the voltage-current conversion circuit converts the amplified analog voltage signal into an analog current signal and sends it to the current conversion circuit, the current conversion circuit converts the analog current signal into the standard current signal and sends it to the measuring unit; The output voltage feedback circuit collects the voltage signal output by the voltage generating circuit, and sends the voltage signal to the control module; the control module generates a voltage control signal according to the voltage signal, and sends the voltage control signal to the voltage generating circuit; the voltage generating circuit generates a standard voltage signal according to the voltage control signal, and sends the standard voltage signal to the measuring unit; The control module sends the standard measurement result to the measurement unit, and the measurement unit generates an actual measurement result according to the standard current signal and the standard voltage signal, and performs calibration according to the standard measurement result and the actual measurement result.

2. The calibration device for a measuring switch according to claim 1, characterized in that: The voltage-current conversion circuit includes a switch tube V1 and a resistor R1, the control end of the switch tube V1 is connected to the second end of the voltage amplification circuit, the first end of the switch tube V1 is connected to the first end of the current conversion circuit, the second end of the switch tube V1 is connected to the first end of the resistor R1, and the second end of the resistor R1 is grounded.

3. The calibration device for a measuring switch according to claim 2, characterized in that: The voltage amplifier circuit includes an operational amplifier U1, a non-inverting input terminal of the operational amplifier U1 is connected to a first terminal of the control module, an output terminal of the operational amplifier U1 is connected to a control terminal of the switch tube V1, and an inverting input terminal of the operational amplifier U1 is connected to a second terminal of the switch tube V1.

4. The calibration device for a measuring switch according to claim 1, characterized in that: The control module includes a PC host computer, an MCU, an analog-to-digital conversion unit, a digital-to-analog conversion unit, a first RS485 communication unit and a second RS485 communication unit, wherein a first end of the PC host computer is connected to a first end of the first RS485 communication unit, a second end of the first RS485 communication unit is connected to a second end of the measuring unit, a second end of the PC host computer is connected to a first end of the second RS485 communication unit, a second end of the second RS485 communication unit is connected to a first end of the MCU, a second end of the MCU is connected to a first end of the digital-to-analog conversion unit, a second end of the digital-to-analog conversion unit is connected to a first end of the standard current signal generating module, a third end of the MCU is connected to a first end of the analog-to-digital conversion unit, a second end of the analog-to-digital conversion unit is connected to a second end of the standard voltage signal generating module, and a fourth end of the MCU is connected to a second end of the standard voltage signal generating module; The PC host computer sends a voltage output setting instruction to the MCU, the analog-to-digital conversion unit collects the voltage signal output by the standard voltage signal generating module and sends it to the MCU, the MCU generates the voltage control signal according to the voltage output setting instruction and the voltage signal output by the standard voltage signal generating module, and sends the voltage control signal to the standard voltage signal generating module; The PC host computer sends a current output setting instruction to the MCU, the MCU generates a current output control signal according to the current output setting instruction, and sends the current output control signal to the digital-to-analog conversion unit, the digital-to-analog conversion unit generates the analog voltage signal according to the current output control signal, and sends the analog voltage signal to the standard current signal generating module.

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