Calibration device

Abstract

The application discloses a kind of calibration devices, it is related to test technical field, calibration device includes voltage source, current source, switching circuit module and detection circuit, voltage source is used to output calibration voltage;Current source is used to output calibration current;Switching circuit module one end is electrically connected with voltage source, current source, the other end of switching circuit module is used to be electrically connected with the equipment to be measured;Switching circuit module is used to switch the connection of voltage source and the equipment to be measured on, or switching current source and the connection of the equipment to be measured on;Detection circuit is electrically connected with the equipment to be measured, for detecting the actual voltage of equipment to be measured when voltage source and the equipment to be measured connection on, to carry out voltage calibration to equipment to be measured according to calibration voltage and actual voltage;Actual current of equipment to be measured is detected when current source and the equipment to be measured connection on, to carry out current calibration to equipment to be measured according to calibration current and actual current.The output current voltage of calibration current transformer and other equipment to be measured.

Description

Technical Field

[0001] This application relates to the field of testing technology, and more particularly to a calibration device. Background Technology

[0002] Equipment such as converters generally require calibration before leaving the factory or before use, especially current and voltage calibration. Taking energy storage converters as an example, as key equipment for connecting energy storage batteries to the power system, energy storage converters control the charging and discharging process of batteries, perform AC-DC conversion, and can directly supply power to AC loads in the absence of a power grid. Due to differences between different machines, the output voltage and current errors of the products can be significant, therefore, the voltage and current of energy storage converters need to be calibrated. Utility Model Content

[0003] The main purpose of this application is to provide a calibration device that aims to solve the technical problem of calibrating the output current and voltage of the device under test.

[0004] To achieve the above objectives, this application proposes a calibration device, comprising:

[0005] A voltage source used to output calibration voltage;

[0006] A current source is used to output a calibration current.

[0007] A switching circuit module, one end of which is electrically connected to the voltage source and the current source respectively, and the other end of which is used to be electrically connected to the device under test; the switching circuit module is used to switch the connection between the voltage source and the device under test, or to switch the connection between the current source and the device under test;

[0008] A detection circuit is configured to be electrically connected to the device under test (DUT), and to detect the actual voltage output by the DUT when the voltage source is connected to the DUT, so as to perform voltage calibration on the DUT based on the calibration voltage and the actual voltage; and to detect the actual current output by the DUT when the current source is connected to the DUT, so as to perform current calibration on the DUT based on the calibration current and the actual current.

[0009] In one embodiment, the switching circuit module includes a first gating circuit and a second gating circuit; one end of the first gating circuit is electrically connected to the voltage source, and the other end is used to electrically connect to the device under test; one end of the second gating circuit is electrically connected to the current source, and the other end is used to electrically connect to the device under test.

[0010] When the first gating circuit is closed and the second gating circuit is open, the voltage source is electrically connected to the device under test through the first gating circuit;

[0011] When the first gating circuit is open and the second gating circuit is closed, the current source is electrically connected to the device under test through the second gating circuit.

[0012] In one embodiment, the first gating circuit includes a forward voltage gating branch and a reverse voltage gating branch;

[0013] When the forward voltage gating branch is closed and the reverse voltage gating branch is open, the voltage source outputs a forward calibration voltage to the device under test.

[0014] When the forward voltage selection branch is open and the reverse voltage selection branch is closed, the voltage source outputs a reverse calibration voltage to the device under test.

[0015] In one embodiment, the second gating circuit includes a forward current gating branch and a reverse current gating branch;

[0016] When the forward current selection branch is closed and the reverse current selection branch is open, the current source outputs a forward calibration current to the device under test.

[0017] When the forward current selection branch is open and the reverse current selection branch is closed, the current source outputs a reverse calibration current to the device under test.

[0018] In one embodiment, the calibration device includes an output port group for connecting to the device under test, the output port group including an AC power port group, a neutral connection port and a DC power port group, the DC power port group including a first positive port, a first negative port, a second positive port and a second negative port;

[0019] Wherein, the first positive port and the first negative port form a first DC power supply circuit, and the second positive port and the second negative port form a second DC power supply circuit;

[0020] The AC power port group includes three phase interfaces, and a phase-to-phase reverse connection circuit is provided between the three phase interfaces.

[0021] In one embodiment, the three phase interfaces include interface R, interface S, and interface T, and the phase-to-phase reverse connection circuit includes a reverse connection switch, wherein interface R is connected to interface S through the reverse connection switch.

[0022] In one embodiment, the switching circuit module includes a first output terminal block and a second output terminal block, wherein the first output terminal block is electrically connected to the AC power port group, the first positive port, and the second positive port;

[0023] The second output terminal block is electrically connected to the AC power port group, the neutral wire connection port, the first negative terminal port, and the second negative terminal port.

[0024] In one embodiment, the calibration device further includes a control circuit and an aluminum-cased resistor, the aluminum-cased resistor being used to discharge electrical energy from the device under test;

[0025] The aluminum-cased resistor is connected between the first output terminal block and the second output terminal block. The control circuit is electrically connected to the aluminum-cased resistor and is used to control the aluminum-cased resistor to work after receiving a voltage calibration completion signal.

[0026] In one embodiment, the first selection circuit includes a first relay, a second relay, a third relay, a fourth relay, a first fuse, and a second fuse. The positive terminal of the voltage source is electrically connected to the first terminal of the first relay and the first terminal of the third relay, respectively. The negative terminal of the voltage source is electrically connected to the first terminal of the second relay and the first terminal of the fourth relay, respectively. The second terminals of the first relay and the second relay are electrically connected to the AC terminal and the positive terminal of the device under test, respectively, through the first fuse. The second terminals of the third relay and the fourth relay are electrically connected to the AC terminal, the neutral terminal, and the negative terminal of the device under test, respectively, through the second fuse.

[0027] In one embodiment, the second selection circuit includes a fifth relay, a sixth relay, a seventh relay, and an eighth relay. The positive terminal of the current source is electrically connected to the first terminal of the fifth relay and the first terminal of the seventh relay, respectively. The negative terminal of the current source is electrically connected to the first terminal of the sixth relay and the first terminal of the eighth relay, respectively. The second terminals of the fifth relay and the sixth relay are electrically connected to the AC terminal and the positive terminal of the device under test, respectively. The second terminals of the seventh relay and the eighth relay are electrically connected to the AC terminal, the neutral terminal, and the negative terminal of the device under test, respectively.

[0028] In one embodiment, the calibration device further includes a control circuit, which is electrically connected to the switching circuit module and is used to control the operation of the switching circuit module.

[0029] The control circuit is also connected to the detection circuit. Specifically, the control circuit is used to control the switching circuit module to work according to the actual voltage output by the device under test detected by the detection circuit. After receiving a voltage calibration completion signal, the control circuit module switches the connection between the voltage source and the device under test to disconnect; and when receiving a voltage safety signal, the control circuit module switches the connection between the current source and the device under test to connect.

[0030] In one embodiment, the calibration device further includes an isolation circuit, the output of which is electrically connected to the input of the voltage source and the current source, respectively, and the input of which is electrically connected to an external AC power source.

[0031] The voltage source is used to output the calibration voltage required for calibration, and the current source is used to output the calibration current required for calibration, so as to meet different calibration requirements.

[0032] The switching circuit module enables automatic switching between voltage and current sources. After voltage calibration is complete, the switching circuit module switches the connection between the voltage source and the device under test to the connection between the current source and the device under test. The switching circuit module not only reduces the time spent on manual wiring but also improves the safety of testing and effectively enhances calibration efficiency.

[0033] The detection circuit detects the actual voltage or current output of the device under test (DUT), enabling voltage or current calibration of the DUT. It is suitable for the calibration needs of different types of DUTs and ensures that the performance and sampling accuracy of the DUT meet the requirements. Attached Figure Description

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 One of the electrical schematic diagrams provided for an embodiment of the calibration device of this application;

[0037] Figure 2 A second electrical schematic diagram provided for an embodiment of the calibration device of this application;

[0038] Figure 3 Electrical schematic diagram three of an embodiment of the calibration device of this application;

[0039] Figure 4 Electrical schematic diagram four provided for an embodiment of the calibration device of this application;

[0040] Figure 5 Fifth electrical schematic diagram provided for an embodiment of the calibration device of this application;

[0041] Figure 6 Electrical schematic diagram six provided for an embodiment of the calibration device of this application;

[0042] Figure 7 This is a schematic diagram of a structure provided for one embodiment of the calibration device of this application.

[0043] Explanation of icon numbers:

[0044] 100. Voltage source;

[0045] 200. Current source;

[0046] 300. Switching circuit module;

[0047] 400. Control circuit;

[0048] 501, First terminal block; 502, Second terminal block; 503, Third terminal block.

[0049] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0050] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0051] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0052] Equipment such as converters generally require calibration before leaving the factory or before use. Taking a power storage converter (PCS) as an example, a PCS is a key device for connecting energy storage batteries to the power system. It controls the charging and discharging process of the battery, performs AC-DC conversion, and can directly supply power to AC loads in the absence of a power grid. In recent years, the energy storage industry has experienced rapid development. At the same time, issues such as cost control, safety assurance, equipment lifespan, and operation and maintenance of PCS have increasingly attracted attention. High protection and efficient heat dissipation capabilities are crucial to ensuring the reliability of power electronic equipment during operation. However, the components in the PCS sampling circuit have tolerances, and different machines vary, leading to significant errors in the output voltage and current. Therefore, it is necessary to calibrate the voltage and current sampling data of converters and other equipment to ensure sampling accuracy.

[0053] To achieve voltage and current calibration of the device under test, this application proposes a calibration device. (Refer to...) Figure 1The calibration device is used to calibrate the device under test (DUT) based on the voltage output by voltage source 100, the current output by current source 200, and the detected actual voltage and current of the DUT. The calibration device of this application includes a voltage source 100, a current source 200, a switching circuit module 300, and a detection circuit. Voltage source 100 is used to output a calibration voltage; current source 200 is used to output a calibration current. Voltage source 100, as a voltage simulation device, is typically optionally a DC voltage source used to output the calibration voltage required for calibration. The value of this calibration voltage is adjustable to meet different calibration requirements. Similarly, current source 200, as a current simulation device, is typically optionally a DC current source used to output the calibration current required for calibration, and the magnitude of the calibration current is also adjustable.

[0054] One end of the switching circuit module 300 is electrically connected to the voltage source 100 and the current source 200 respectively, and the other end of the switching circuit module 300 is used to electrically connect to the device under test; the switching circuit module 300 is used to switch the connection between the voltage source 100 and the device under test, or to switch the connection between the current source 200 and the device under test.

[0055] The detection circuit is used to electrically connect to the device under test (DUT) and to detect the actual voltage output by the DUT when the voltage source 100 is connected to the DUT, so as to perform voltage calibration on the DUT based on the calibration voltage and the actual voltage; and to detect the actual current output by the DUT when the current source 200 is connected to the DUT, so as to perform current calibration on the DUT based on the calibration current and the actual current.

[0056] Optionally, the switching circuit module 300 includes electronic components such as relays and circuit breakers, and the switching between different circuits is achieved by turning these components on or off. In the embodiments of this application, the switching circuit module 300 is designed with dual DC1 and DC2 branches or other forms of switching circuits to provide flexibility. When the switching circuit module 300 connects the voltage source 100 to the device under test, the voltage output by the voltage source 100 is used as a calibration voltage for voltage calibration of the device under test; and when the switching circuit module 300 connects the current source 200 to the device under test, the current output by the current source 200 is used as a calibration current for current calibration of the device under test.

[0057] During calibration, the switching circuit module 300 can automatically switch between the voltage source 100 and the current source 200. Specifically, one of the DC1 and DC2 branches is used as the voltage calibration circuit, and the other as the current calibration circuit. After voltage calibration is completed, the connection between the voltage source 100 and the device under test (DUT) is switched to the connection between the current source 200 and the DUT through automatic switching loop control, that is, the working branch is switched from the DC1 branch to the DC2 branch (or the DC2 branch is switched back to the DC1 branch). The switching circuit module 300 can switch the connection between the voltage source 100 or the current source 200 and the DUT manually; or it can automatically switch the connection between the voltage source 100 or the current source 200 and the DUT through host computer software or control logic, thereby further improving the automation and efficiency of calibration, reducing the time spent on manual line changes, improving test safety, and effectively improving calibration efficiency.

[0058] The detection circuit includes components such as sensors, amplifiers, and analog-to-digital converters, used to detect the actual voltage or current output by the device under test (DUT) when the voltage source 100 or current source 200 is connected. By comparing the detected actual voltage with the calibration voltage output by the voltage source 100, and by comparing the detected actual current with the calibration current output by the current source 200, the voltage or current of the DUT can be calibrated.

[0059] To address the need for calibrating the output voltage and current of the device under test (DUT) to ensure accurate sampling, this application's embodiment outputs the required calibration voltage via voltage source 100 and the required calibration current via current source 200. A switching circuit module 300 switches the connection between voltage source 100 and the DUT to achieve voltage calibration. By comparing the actual voltage detected by the detection circuit with the calibration voltage output by voltage source 100, voltage calibration of the DUT can be performed, ensuring the accuracy of voltage sampling. Similarly, switching the connection between current source 200 and the DUT via the switching circuit module 300 enables current calibration. By comparing the actual current detected by the detection circuit with the calibration current output by current source 200, current calibration of the DUT can be performed, ensuring the accuracy of current sampling. This not only improves testing safety and effectively enhances calibration efficiency but also ensures that the performance and sampling accuracy of the DUT meet requirements. Furthermore, the switching circuit module 300 supports multi-mode calibration, meeting the calibration needs of different types of converters and other DUTs.

[0060] Taking voltage calibration as an example, the voltage of the device under test (DUT) is calibrated based on the actual voltage output by the DUT detected by the detection circuit. Specifically, this can be achieved by calculating correction parameters or other calibration values. After voltage calibration, the voltage source 100 is controlled to output the required calibration voltage. The detection circuit detects the actual voltage output by the DUT. If the difference between the detected actual voltage and the calibration voltage is within a preset range, the voltage calibration is considered successful. Once voltage calibration is complete, an automatic switching loop control switches the connection between the voltage source 100 and the DUT to that between the current source 200 and the DUT, thus switching the voltage calibration to current calibration. An example of current calibration can be referenced accordingly and will not be elaborated further here.

[0061] Reference Figure 1 In one embodiment, the switching circuit module 300 includes a first gating circuit and a second gating circuit. One end of the first gating circuit is electrically connected to the voltage source 100, and the other end is used for electrical connection to the device under test (DUT). One end of the second gating circuit is electrically connected to the current source 200, and the other end is used for electrical connection to the DUT. When the first gating circuit is closed and the second gating circuit is open, the voltage source 100 is electrically connected to the DUT through the first gating circuit; when the first gating circuit is open and the second gating circuit is closed, the current source 200 is electrically connected to the DUT through the second gating circuit.

[0062] The switching circuit module 300 is designed with dual branches, DC1 and DC2. One branch serves as a voltage calibration circuit (including a first gating circuit), and the other as a current calibration circuit (including a second gating circuit). One end of the first gating circuit is electrically connected to the voltage source 100, and the other end is used for electrical connection to the device under test (DUT). One end of the second gating circuit is electrically connected to the current source 200, and the other end is used for electrical connection to the DUT. The first and second gating circuits can be controlled independently. The main function of the first gating circuit is to control the electrical connection between the voltage source 100 and the DUT. During the voltage calibration phase, the first gating circuit is closed, allowing the voltage source 100 to connect to the DUT through this circuit, thereby calibrating the voltage output of the DUT. The main function of the second gating circuit is to control the electrical connection between the current source 200 and the DUT. During the current calibration phase, the second gating circuit is closed, allowing the current source 200 to connect to the DUT through this circuit, thereby calibrating the current output of the DUT.

[0063] The design of the first and second gating circuits provides the calibration device with efficient, flexible, and safe calibration functions, ensuring that the device under test can be accurately tested for voltage and current under different calibration conditions. Switching between these two gating circuits can be achieved through the on / off states of electronic components such as relays and circuit breakers located between them and within each circuit. This switching can be done manually or automatically through host computer software or control logic, thereby further improving the automation and efficiency of calibration.

[0064] Reference Figure 1 , Figure 2 In one embodiment, the calibration device further includes a control circuit 400, which is electrically connected to the switching circuit module 300. The control circuit 400 is used to control the operation of the switching circuit module 300. This control circuit can be used to control the connection between the voltage source 100 and the device under test; or, to control the connection between the current source 200 and the device under test.

[0065] In some alternative embodiments of this application, such as Figure 2 The control circuit 400 shown controls the operation of the switching circuit module 300 to achieve one or more of the following functions: controlling the connection between the voltage source 100 and the device under test (DUT); controlling the connection between the current source 200 and the DUT; and automatically switching the connection between the voltage source 100 and the DUT to the current source 200 and the DUT (i.e., automatic switching from voltage calibration to current calibration). Based on the received signal, the control circuit 400 controls the first and second gating circuits in the switching circuit module 300 to close or open, thereby completing voltage calibration, current calibration, and the automatic switching between them. This automates the calibration process, significantly reduces manual intervention, and effectively improves calibration efficiency, accuracy, and safety.

[0066] Taking voltage calibration as an example:

[0067] The control circuit 400 controls the voltage source 100 to output the required calibration voltage (e.g., ...). Figure 3 The output voltage shown is 24V calibration voltage. Based on the actual voltage output of the device under test (DUT) detected by the detection circuit, the DUT is calibrated. Specifically, this can be achieved by calculating correction parameters or other calibration values. After voltage calibration, the voltage source 100 outputs the required calibration voltage. The detection circuit detects the actual voltage output of the DUT. If the difference between the detected actual voltage and the calibration voltage is within a preset range, the voltage calibration is considered successful. Voltage calibration can be, but is not limited to, forward voltage calibration, reverse voltage calibration, and AC voltage calibration.

[0068] Taking current calibration as an example:

[0069] The control circuit 400 controls the current source 200 to output the required calibration current. Based on the actual current output by the device under test (DUT) detected by the detection circuit, the DUT is calibrated. This calibration can be achieved by calculating correction parameters or other calibration values. After calibration, the current source 200 outputs the required calibration current. The detection circuit detects the actual current output by the DUT. If the difference between the detected actual current and the calibration current is within a preset range, the current calibration is considered successful. Current calibration can be, but is not limited to, forward current calibration, reverse current calibration, and AC current calibration.

[0070] Reference Figure 3 The calibration device includes multiple switching circuits, including the aforementioned switching circuit module 300. A control circuit 400 is connected to the multiple switching circuits and is used to control the switching circuits to activate and execute corresponding calibration functions, or to control the switching circuits to deactivate and stop executing corresponding calibration functions. In addition to the aforementioned voltage and current calibrations, some of the multiple switching circuits are also used to implement emergency stop control (e.g., ...). Figure 3 The DI shown); some switching circuits are also used as reserved circuits (such as DI); Figure 3 The D0 shown can be used to achieve other calibration functions; the specific settings can be adjusted according to actual conditions, and are not limited here.

[0071] Reference Figure 1 In one embodiment, the calibration device further includes an aluminum-cased resistor used to discharge electrical energy from the device under test. The aluminum-cased resistor is connected between the first output terminal block S1 and the second output terminal block S2. The control circuit 400 is electrically connected to the aluminum-cased resistor and is used to control the aluminum-cased resistor to operate after receiving a voltage calibration completion signal.

[0072] The control circuit 400 is also connected to the detection circuit. The control circuit 400 is used to control the switching circuit module 300 to operate according to the actual voltage output of the device under test detected by the detection circuit, so as to control the switching circuit module 300 to switch the connection between the voltage source 100 and the device under test, or to control the switching circuit module 300 to switch the connection between the current source 200 and the device under test.

[0073] During the calibration process, the device under test may output excess electrical energy. This energy needs to be safely discharged through an aluminum-cased resistor to avoid energy accumulation that could damage the device and to achieve accurate, efficient, and safe calibration of the device under test.

[0074] For example, aluminum-cased resistors include, Figure 1The first aluminum-cased resistor R1 and the second aluminum-cased resistor R2 shown are used by the control circuit 400 to control the switching circuit module 300 to operate based on the actual voltage output by the device under test detected by the detection circuit. Specifically, it controls the switching circuit module 300 to switch the connection between the voltage source 100 and the device under test, and after receiving the voltage calibration completion signal, it controls the switching circuit module 300 to switch the connection between the voltage source 100 and the device under test, controlling... Figure 1 The aluminum-cased resistors R1 and R2 are shown to operate; and upon receiving a voltage safety signal, the switching circuit module 300 controls the switching circuit module 300 to switch the connection between the current source 200 and the device under test (DUT). This is used to calibrate the DUT using the voltage output of the voltage source 100 as the calibration voltage when the switching circuit module 300 connects the voltage source 100 to the DUT; after voltage calibration is completed, based on the received voltage calibration completion signal, the switching circuit module 300 controls the switching circuit module 300 to disconnect the connection between the voltage source 100 and the DUT, and controls the aluminum-cased resistors to operate, discharging the electrical energy of the DUT through the aluminum-cased resistors until the voltage of the DUT drops to a safe standard, at which point a voltage safety signal is received; based on the received voltage safety signal, the switching circuit module 300 controls the switching circuit module 300 to switch the connection between the current source 200 and the DUT, using the current output of the current source 200 as the calibration current when the switching circuit module 300 connects the current source 200 to the DUT, and performing current calibration on the DUT.

[0075] By incorporating an aluminum-cased resistor, after voltage calibration, the device under test (DUT) is discharged using the resistor until its voltage drops below a safe standard (e.g., 36V). Subsequently, the control circuit 400 reconnects the current source 200 to the DUT to achieve current calibration. The addition of the aluminum-cased resistor significantly reduces discharge time and improves calibration efficiency. Furthermore, the use of the aluminum-cased resistor enhances the safety of the calibration process, ensuring that the DUT is not damaged by energy accumulation during discharge.

[0076] Reference Figure 1 In one embodiment, the first gating circuit includes a forward voltage gating branch and a reverse voltage gating branch. When the forward voltage gating branch is closed and the reverse voltage gating branch is open, the voltage source 100 outputs a forward calibration voltage to the device under test; when the forward voltage gating branch is open and the reverse voltage gating branch is closed, the voltage source 100 outputs a reverse calibration voltage to the device under test.

[0077] The forward and reverse voltage selection branches of the first selection circuit are controlled to close or open by the control circuit 400, thereby determining the output direction of the voltage source 100. When the forward voltage selection branch is closed and the reverse voltage selection branch is open, the voltage source 100 outputs a forward calibration voltage to the device under test (DUT) through the forward voltage selection branch. This is used to calibrate the output accuracy of the DUT under forward voltage, ensuring the accuracy of the DUT in forward voltage operating mode. When the reverse voltage selection branch is closed and the forward voltage selection branch is open, the voltage source 100 outputs a reverse calibration voltage to the DUT through the reverse voltage selection branch. This is used to calibrate the output accuracy of the DUT under reverse voltage, ensuring the stability of the DUT in reverse voltage operating mode. By setting the forward and reverse voltage selection branches in this way, the first selection circuit can flexibly switch the output direction of the voltage source 100, achieving comprehensive calibration of the DUT, meeting the requirements of both forward and reverse voltage calibration, and improving calibration efficiency and accuracy.

[0078] Reference Figure 1 In one embodiment, the second gating circuit includes a forward current gating branch and a reverse current gating branch. When the forward current gating branch is closed and the reverse current gating branch is open, the current source 200 outputs a forward calibration current to the device under test; when the forward current gating branch is open and the reverse current gating branch is closed, the current source 200 outputs a reverse calibration current to the device under test.

[0079] The forward and reverse current selection branches of the second selection circuit are controlled to close or open by the control circuit 400, thereby determining the output direction of the current source 200: When the forward current selection branch is closed and the reverse current selection branch is open, the current source 200 outputs a forward calibration current to the device under test (DUT) through the forward current selection branch. This is used to calibrate the output accuracy of the DUT under forward current, ensuring the accuracy of the DUT in forward current operating mode. When the reverse current selection branch is closed and the forward current selection branch is open, the current source 200 outputs a reverse calibration current to the DUT through the reverse current selection branch. This is used to calibrate the output accuracy of the DUT under reverse current, ensuring the stability of the DUT in reverse current operating mode. By setting up the forward and reverse current selection branches in this way, the second selection circuit can flexibly switch the output direction of the current source 200, achieving comprehensive calibration of the DUT, meeting the requirements of both forward and reverse current calibration, and improving calibration efficiency and accuracy.

[0080] Reference Figure 1In one embodiment, the calibration device includes an output port group for connecting to the device under test. The output port group includes an AC power port group, a neutral connection port, and a DC power port group. The DC power port group includes a first positive port DC1+, a first negative port DC1-, a second positive port DC2+, and a second negative port DC2+.

[0081] The first positive port DC1+ and the first negative port DC1- form the first DC power supply loop, and the second positive port DC2+ and the second negative port DC2- form the second DC power supply loop. The AC power supply port group includes three phase interfaces, and a phase-to-phase reverse connection circuit is provided between the three phase interfaces.

[0082] The output port group serves as the connection interface between the calibration device and the device under test (DUT), used to transmit calibration signals and power. Specifically, the neutral connection port is used to connect to the neutral wire of the AC power supply, ensuring proper grounding; the AC power port group is used to provide AC power to the DUT during calibration, or, in some implementation scenarios, to detect the AC signal output by the DUT; the DC power interface group is used to provide DC power to the DUT during calibration, or, in some implementation scenarios, to detect the DC signal output by the DUT. Taking an application to a converter as an example (the converter can be a rectifier, inverter, etc.), the AC power port group, neutral connection port, and positive ports (first positive port DC1+, second positive port DC2+), negative ports (first negative port DC1-, second negative port DC12-) are connected to the AC terminal, neutral terminal, DC positive terminal, and DC negative terminal of the converter, respectively.

[0083] The DC power supply port group can achieve forward voltage calibration, reverse voltage calibration, forward current calibration, and reverse current calibration through two independent DC power supply loops; the AC power supply port group is used to connect a three-phase AC power supply, including three phase interfaces (interface R, interface S, and interface T), each phase interface is connected to the corresponding phase input terminal of the device under test.

[0084] Optionally, the AC power port group includes a first AC port, a second AC port, and a third AC port, corresponding to interface R, interface S, and interface T of the three phase interfaces, respectively. In the embodiments of this application, the phase-to-phase reverse connection circuit includes a reverse connection switch KZ22, and interface R is connected to interface S through the reverse connection switch KZ22. The phase-to-phase reverse connection circuit is set between the three phase interfaces to detect and prevent phase wiring errors. When a phase wiring error occurs, the phase-to-phase reverse connection circuit can issue an alarm or automatically switch phases to ensure the safety and accuracy of the calibration process. In addition, the phase-to-phase reverse connection short circuit is also used to implement the RS phase short circuit test. Through the RS phase short circuit test, the return current of the device under test can be verified to be normal before calibration, preventing faults from occurring during the calibration process, thereby avoiding damage to the converter product.

[0085] Reference Figure 1 In one embodiment, the switching circuit module 300 includes a first output terminal block S1 and a second output terminal block S2. The first output terminal block S1 is electrically connected to the AC power port group (interface R, interface S and interface T), the first positive port DC1+, and the second positive port DC2+.

[0086] The second output terminal block S2 is electrically connected to the AC power port group (interface R, interface S and interface T), the neutral connection port N, the first negative port DC1-, and the second negative port DC2-.

[0087] Through the first output terminal block S1 and the second output terminal block S2, the switching circuit module achieves electrical isolation and protection functions, effectively preventing damage to the circuit module and the converter under test caused by abnormal conditions such as excessive current, excessive voltage, or short circuit. At the same time, the first output terminal block S1 and the second output terminal block S2 also provide a safer, more reliable, and flexible connection method, allowing for easy adjustment of the connection relationship in different application scenarios to meet diverse testing needs.

[0088] The first selection circuit includes a first relay KZ1, a second relay KZ2, a third relay KZ3, a fourth relay KZ4, a first fuse FU3, and a second fuse FU4. The positive terminal of the voltage source 100 is electrically connected to the first terminal of the first relay KZ1 and the first terminal of the third relay KZ3, respectively. The negative terminal of the voltage source 100 is electrically connected to the first terminal of the second relay KZ2 and the first terminal of the fourth relay KZ4, respectively. The second terminals of the first relay KZ1 and the second relay KZ2 are electrically connected to the AC terminal and the positive terminal of the device under test through the first fuse FU3, respectively. The second terminals of the third relay KZ3 and the fourth relay KZ4 are electrically connected to the AC terminal, the neutral terminal, and the negative terminal of the device under test through the second fuse FU4, respectively.

[0089] Specifically, the second terminals of the first relay KZ1 and the second relay KZ2 are electrically connected to the second output terminal block S1 via the first fuse FU3, respectively, to achieve electrical connection with the AC terminal and positive terminal of the device under test (DUT). The second terminals of the third relay KZ3 and the fourth relay KZ4 are electrically connected to the second output terminal block S2 via the second fuse FU4, respectively, to achieve electrical connection with the AC terminal, neutral terminal, and negative terminal of the DUT. The switching circuit module 300 can flexibly switch the output direction of the voltage source 100 to achieve positive and reverse voltage calibration functions, meeting the calibration requirements of the DUT in different operating modes. Specifically, the switching circuit module 300 controls the on / off states of different relays (KZ1, KZ2, KZ3, KZ4) to achieve connection switching between the voltage source 100 and the AC power port group (interfaces R, S, T) and the DC power port (DC1+, DC1-, DC2+, DC2-). During forward voltage calibration, the first relay KZ1 and the second relay KZ2 are closed, while the third relay KZ3 and the fourth relay KZ4 are open. Voltage source 100 outputs a forward calibration voltage to the device under test (DUT) through the forward path formed by the closed first relay KZ1 and the second relay KZ2. During reverse voltage calibration, the third relay KZ3 and the fourth relay KZ4 are closed, while the first relay KZ1 and the second relay KZ2 are open. Voltage source 100 outputs a reverse calibration voltage to the DUT through the reverse path formed by the closed third relay KZ3 and the fourth relay KZ4. The on / off state of each relay is precisely controlled by control circuit 400. Control circuit 400 dynamically adjusts the on / off state of the relays based on feedback signals from the detection circuit to ensure the automation and accuracy of the calibration process.

[0090] Fuses (FU3, FU4) are connected in series in the circuit to provide overcurrent protection. When the current exceeds the set value, the fuse will automatically disconnect the circuit to prevent equipment damage due to overload. This not only achieves the calibration functions of forward voltage, reverse voltage, forward current, and reverse current, but also reduces manual intervention, improving calibration efficiency and safety.

[0091] Reference Figure 1 In one embodiment, the second gating circuit includes a fifth relay KZ5, a sixth relay KZ6, a seventh relay KZ7, and an eighth relay KZ8. The positive terminal of the current source 200 is electrically connected to the first terminal of the fifth relay KZ5 and the first terminal of the seventh relay KZ7, respectively. The negative terminal of the current source 200 is electrically connected to the first terminal of the sixth relay KZ6 and the first terminal of the eighth relay KZ8, respectively. The second terminal of the fifth relay KZ5 and the second terminal of the sixth relay KZ6 are electrically connected to the AC terminal and the positive terminal of the device under test, respectively. The second terminal of the seventh relay KZ7 and the second terminal of the eighth relay KZ8 are electrically connected to the AC terminal, the neutral terminal, and the negative terminal of the device under test, respectively.

[0092] Specifically, the second terminal of the fifth relay KZ5 and the second terminal of the sixth relay KZ6 are electrically connected to the first output terminal block S1 (and specifically to the first terminal of the first output terminal block S1) to achieve electrical connection with the AC terminal and positive terminal of the device under test; the second terminal of the seventh relay KZ7 and the second terminal of the eighth relay KZ8 are electrically connected to the second output terminal block S2 (and specifically to the first terminal of the second output terminal block S2) to achieve electrical connection with the AC terminal, neutral terminal and negative terminal of the device under test.

[0093] The switching circuit module 300 can flexibly switch the output direction of the current source 200 to achieve forward and reverse current calibration functions, meeting the calibration requirements of the device under test in different operating modes. Specifically, the switching circuit module 300 controls the on / off states of different relays (KZ5, KZ6, KZ7, KZ8) to switch the connection between the current source 200 and the AC power port group (interfaces R, S, T) and the DC power port (DC1+, DC1-, DC2+, DC2-). During forward current calibration, the fifth relay KZ5 and the sixth relay KZ6 are closed, and the seventh relay KZ7 and the eighth relay KZ8 are open. The current source 200 outputs a forward calibration current to the device under test through the forward path formed by the closed fifth relay KZ5 and the sixth relay KZ6. During reverse current calibration, the seventh relay KZ7 and the eighth relay KZ8 are closed, while the fifth relay KZ5 and the sixth relay KZ6 are open. The current source 200 outputs a reverse calibration current to the device under test through the reverse path formed by the closed seventh relay KZ7 and the eighth relay KZ8. The on / off state of each relay is precisely controlled by the control circuit 400. The control circuit 400 dynamically adjusts the on / off state of the relays based on the feedback signal from the detection circuit to ensure the automation and accuracy of the calibration process.

[0094] Reference Figure 1 Furthermore, the second end of the first output terminal block S1 is connected to port R via relay KZ9; the second end of the first output terminal block S1 is connected to port S via relay KZ11; the second end of the first output terminal block S1 is connected to port T via relay KZ13; the second end of the second output terminal block S2 is connected to port R via relay KZ10; the second end of the second output terminal block S2 is connected to port S via relay KZ12; the second end of the second output terminal block S2 is connected to port T via relay KZ14; and the second end of the second output terminal block S12 is connected to port N via relay KZ15.

[0095] Specifically, the second end of the first output terminal block S1 is connected to the first positive port DC1+ via relay KZ16; the second end of the first output terminal block S1 is connected to the second positive port DC2+ via relay KZ18; the second end of the second output terminal block S2 is connected to the first negative port DC1- via relay KZ17; the second end of the second output terminal block S2 is connected to the second negative port DC2- via relay KZ19; and the second end of the second output terminal block S2 is also connected to the second positive port DC2+ via relay KZ23.

[0096] The above settings enable automatic switching between DC dual branches. During dual-branch model calibration, after voltage calibration, the system automatically switches to current switching. Previously, related technologies required manual measurement of voltage and manual wire switching before current calibration. However, the improved device in this application adds an additional branch and automatically switches the circuit via host computer software, reducing manual wire switching time and ensuring personnel safety during testing.

[0097] The aforementioned aluminum-cased resistor is used to discharge electrical energy from the device under test. The aluminum-cased resistor can be connected between the first output terminal block S1 and the second output terminal block S2. The control circuit 400 is electrically connected to the aluminum-cased resistor and is used to control the operation of the aluminum-cased resistor after receiving a voltage calibration completion signal.

[0098] In some embodiments, there are two aluminum-cased resistors, including a first aluminum-cased resistor R1 and a second aluminum-cased resistor R2. The first end of aluminum-cased resistor R1 is connected to the first end of aluminum-cased resistor R2. The second end of aluminum-cased resistor R1 is connected to the second output terminal block S2 through relay KZ20. The second end of aluminum-cased resistor R2 is connected to the first output terminal block S1 through relay KZ21. This allows the electrical energy of the device under test to be discharged after voltage calibration is completed, until the voltage of the device under test drops below the safety standard.

[0099] The first relay KZ1, the second relay KZ2, the fuse FU3, the first output terminal block S1, the first positive port DC1+, and the second positive port DC2+ are configured as the aforementioned positive voltage selection branch. The positive terminal of the voltage source 100 is connected to the first output terminal block S1 through the first relay KZ1 and the fuse FU3; the negative terminal of the voltage source 100 is connected to the first output terminal block S1 through the second relay KZ2 and the fuse FU3; this is used to output a positive voltage to the device under test.

[0100] The third relay KZ3, the fourth relay KZ4, the fuse FU4, the second output terminal block S2, the first negative port DC1-, and the second negative port DC2- are configured as the aforementioned reverse voltage selection branch. The positive terminal of the voltage source 100 is connected to the second output terminal block S2 through the third relay KZ3 and the fuse FU4; the negative terminal is connected to the second output terminal block S2 through the fourth relay KZ4 and the fuse FU4. The voltage source 100 outputs a reverse voltage to the device under test.

[0101] The fifth relay KZ5, the sixth relay KZ6, the first output terminal block S1, the first positive port DC1+, and the second positive port DC2+ are configured as the aforementioned positive current selection branch. The positive terminal of the current source 200 is connected to the first output terminal block S1 through the fifth relay KZ5, and the negative terminal of the current source 200 is connected to the first output terminal block S1 through the sixth relay KZ6; this is used to output positive current to the device under test.

[0102] The seventh relay KZ7, the eighth relay KZ8, the first output terminal block S1, the first negative port DC1-, and the second negative port DC2- are configured as the aforementioned reverse current selection branch. The positive terminal of the current source 200 is connected to the first output terminal block S1 through the seventh relay KZ7, and the negative terminal of the current source 200 is connected to the second output terminal block S2 through the eighth relay KZ8, for outputting reverse current to the device under test.

[0103] like Figure 4 As shown, in some embodiments, the calibration device is powered by a three-phase power supply, drawing 220V. The calibration device is equipped with a control switch, which is used to start calibration by closing the switch or to stop calibration by closing the switch.

[0104] Reference Figure 5 In one embodiment, the calibration device further includes an isolation circuit, the output of which is electrically connected to the input of the voltage source 100 and the current source 200, respectively, and the input of which is electrically connected to an external AC power source.

[0105] Optionally, the input terminals of voltage source 100 and current source 200 are both used to connect to the power bus. The input terminal of voltage source 100 is connected to the second terminal of circuit breaker Q2 through circuit breaker Q3, and the input terminal of current source 200 is connected to the second terminal of circuit breaker Q2 through circuit breaker Q4; the first terminal of circuit breaker Q2 is connected to the AC power supply, and an isolation transformer T1 is connected between the AC power supply and circuit breaker Q2; the input terminal of isolation transformer T1 is connected to the AC power supply.

[0106] The isolation circuit includes an isolation transformer T1, which isolates the power supply. During the test, when the device under test is started or when a product failure occurs, the isolation transformer plays a protective role, preventing surge voltage from damaging other electrical components.

[0107] When an external AC power source supplies electrical energy to the isolation circuit, the isolation circuit isolates and converts the energy through the isolation transformer T1, then supplies the required electrical energy to the voltage source 100 and the current source 200 respectively. The isolation transformer T1 not only achieves electrical isolation between the input and output circuits, but also ensures a stable and suitable power supply to the voltage source 100 and the current source 200 through its voltage transformation function. During testing, the isolation transformer T1 plays a crucial protective role. When the calibration device starts up or malfunctions, the isolation transformer T1 effectively prevents surge voltages from damaging other electrical components, thereby ensuring the safety and reliability of the entire calibration system.

[0108] Reference Figure 5 Furthermore, the output of the isolation transformer T1 provides AC power to the voltage source 100, current source 200, and the test platform, as well as the display screen. The display screen primarily displays information detected during calibration, parameter information of the device under test, etc. Specifically, the test device also includes a first terminal block 501, a second terminal block 502, and a third terminal block 503. The first terminal block 501 supplies power to the circuit breaker connected to the voltage source 100; the second terminal block 502 supplies power to the circuit breaker connected to the current source 200; and the third terminal block 503 supplies power to the computer (host computer, main unit), other components of the calibration device, and other output devices such as the display screen.

[0109] Reference Figure 6 In some embodiments of this application, the calibration device further includes a communication module, and the control circuit 400 is electrically connected to the communication module to realize communication and communication calibration of the device under test.

[0110] Control circuit 400 via, for example Figure 6 Communication module Figure 7 The interface receives control signals from external sources (such as user input, host computer control commands, sensor signals, etc.) and transmits these signals to sources such as... Figure 1 The switching circuit module 300 is shown. Based on the received signal, the control circuit 400 controls the first and second gating circuits in the switching circuit module 300 to close or open, thereby completing voltage calibration, current calibration, and automatic switching between them. Additionally, the control circuit 400 is also used to transmit control signals via electrical connection to, for example,... Figure 3 The switching circuit shown, such as Figure 6The communication module or other circuit module shown can be used to implement other corresponding calibration functions.

[0111] Taking the device under test as an inverter, rectifier, or other converter as an example, the calibration device of this application can be used to implement any one or more of the following solutions:

[0112] RS phase short-circuit test:

[0113] The R interface of the three phase interfaces is connected to the S interface via the second relay KZ22 to form a phase-to-phase reverse short circuit and to perform RS phase short circuit testing. When an RS phase short circuit test is required, the second relay KZ22 is closed, so that the R interface is directly connected to the S interface, forming a short circuit.

[0114] Under short-circuit conditions, the voltage and current characteristics of the device under test (DUT) are tested when the RS phase is short-circuited, and the normal operation of the product's protection mechanism is verified. By measuring the voltage and current after short-circuiting and comparing them with standard values, it is ensured that the product's performance under phase-to-phase short-circuit conditions meets the requirements. This is used to verify that the return current of the DUT is normal before calibration by passing the RS phase short-circuit test, preventing malfunctions during the calibration process, or even damage to the DUT.

[0115] Automatic switching function for voltage-current calibration

[0116] The host computer software or other terminal devices control components such as relays KZ9-KZ23 through the control circuit 400 to achieve automatic switching from voltage calibration to current calibration. Specifically, the switching circuit module 300 automatically switches the voltage source 100 to be electrically connected to the converter under test via the first gating circuit, and the current source 200 to be electrically connected to the converter under test via the second gating circuit. More specifically, after voltage calibration is completed, the second relay KZ23 is closed, thereby achieving automatic switching between the DC1 branch and the DC2 branch (or vice versa).

[0117] The testing device automatically switches to different power branches, automatically switching from voltage calibration to current calibration, eliminating the need for manual measurement and wire changing. The automatic switching function also reduces manual operation time, improves calibration efficiency, and ensures the safety of testing personnel.

[0118] DC voltage calibration (including forward voltage calibration and reverse voltage calibration)

[0119] Forward voltage calibration:

[0120] Close the first relay KZ1 and the second relay KZ2, so that the positive terminal of the voltage source 100 is connected to the first output terminal block S1 through the first relay KZ1 and the fuse FU3; the negative terminal of the voltage source 100 is connected to the first output terminal block S1 through KZ2 and the fuse FU3. At this time, the voltage source 100 is used to output a positive calibration voltage to the device under test.

[0121] By controlling the voltage output of voltage source 100 to reach the calibration voltage required by the device under test, and simultaneously using a detection circuit (or other high-precision voltage measuring device) to detect the actual voltage of the device under test, the detected actual voltage of the device under test is compared with the calibration voltage, and adjustments are made based on the comparison results until the voltage error of the device under test is within an acceptable range.

[0122] Reverse voltage calibration:

[0123] Close the third relay KZ3 and the fourth relay KZ4, so that the positive terminal of the voltage source 100 is connected to the second output terminal block S2 through the third relay KZ3 and the fuse FU4; the negative terminal is connected to the second output terminal block S2 through the fourth relay KZ4 and the fuse FU4. At this time, the voltage source 100 outputs a reverse calibration voltage to the device under test.

[0124] Similar to the aforementioned forward voltage calibration implementation scheme, during reverse voltage calibration, the output voltage of the voltage source 100 can be adjusted to reach the reverse calibration voltage required by the device under test (DUT). Simultaneously, the actual voltage of the DUT is detected, and the detected actual voltage of the DUT is compared with the reverse calibration voltage. Adjustments are made based on the comparison results until the voltage error of the DUT is within an acceptable range.

[0125] DC current calibration (including forward current calibration and reverse current calibration)

[0126] Forward current calibration:

[0127] Close the fifth relay KZ5 and the sixth relay KZ6, so that the positive terminal of the current source 200 is connected to the first output terminal block S1 through the fifth relay KZ5, and the negative terminal of the current source 200 is connected to the first output terminal block S1 through the sixth relay KZ6. At this time, the current source 200 is used to output a positive calibration current to the device under test.

[0128] The output current of the current source 200 is adjusted to reach the calibration current required by the device under test (DUT). Simultaneously, a detection circuit (or other high-precision current measurement device) is used to detect the actual current of the DUT. The detected actual current is compared with the calibration current, and adjustments are made based on the comparison results until the current error of the DUT is within an acceptable range.

[0129] Reverse current calibration:

[0130] Close the seventh relay KZ7 and the eighth relay KZ8, so that the positive terminal of the current source 200 is connected to the first output terminal block S1 through the seventh relay KZ7, and the negative terminal of the current source 200 is connected to the second output terminal block S2 through the eighth relay KZ8. At this time, the current source 200 is used to output reverse current to the device under test.

[0131] Similar to the aforementioned forward current calibration implementation, during reverse current calibration, the output current of the current source 200 can be adjusted to achieve the reverse calibration current required by the device under test (DUT). Simultaneously, a detection circuit (or other high-precision current measurement device) is used to detect the actual current of the DUT, and the detected actual current is compared with the reverse calibration current. Adjustments are made based on the comparison results until the current error of the DUT is within an acceptable range.

[0132] AC voltage calibration

[0133] The AC power from the AC power supply is output through the isolation transformer T1 to power the voltage source 100, the current source 200, the test platform, and the display screen. At the same time, the AC power from the AC power supply is also connected to the output port group of the device under test (such as interface R, interface S, interface T, and neutral connection port N in the AC power supply port group) through circuit breakers Q2, Q3, Q4, etc.

[0134] Adjust the output voltage of the AC power supply to reach the calibration voltage required by the device under test (DUT); at the same time, use a detection circuit (or a high-precision voltage measuring device) to detect the actual current of the DUT, compare the detected actual current of the DUT with the calibration voltage, and adjust according to the comparison result until the AC voltage error of the DUT is within an acceptable range.

[0135] AC current calibration

[0136] AC power is output to the AC power port of the device under test through components such as AC power supply and isolation transformer T1, while the actual current of the device under test is detected.

[0137] Adjust the output current of the AC power supply to reach the calibration current required by the device under test; at the same time, use a detection circuit (or a high-precision voltage measuring device) to detect the actual current of the device under test, compare the detected actual current with the calibration current, and adjust according to the comparison result until the AC current error of the device under test is within an acceptable range.

[0138] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A calibration device, characterized in that, include: Voltage source (100) for outputting calibration voltage; A current source (200) is used to output calibration current; A switching circuit module (300) is provided, one end of which is electrically connected to the voltage source (100) and the current source (200) respectively, and the other end of which is used to be electrically connected to the device under test; the switching circuit module (300) is used to switch the connection between the voltage source (100) and the device under test, or to switch the connection between the current source (200) and the device under test; The detection circuit is used to be electrically connected to the device under test, and is used to detect the actual voltage output by the device under test when the voltage source (100) is connected to the device under test, so as to perform voltage calibration on the device under test according to the calibration voltage and the actual voltage. In addition, when the current source (200) is connected to the device under test, the actual current output by the device under test is detected so as to perform current calibration on the device under test based on the calibration current and the actual current.

2. The calibration device as described in claim 1, characterized in that, The switching circuit module (300) includes a first gating circuit and a second gating circuit; one end of the first gating circuit is electrically connected to the voltage source (100), and the other end is used to be electrically connected to the device under test; one end of the second gating circuit is electrically connected to the current source (200), and the other end is used to be electrically connected to the device under test. When the first gating circuit is closed and the second gating circuit is open, the voltage source (100) is electrically connected to the device under test through the first gating circuit; When the first gating circuit is open and the second gating circuit is closed, the current source (200) is electrically connected to the device under test through the second gating circuit.

3. The calibration device as described in claim 2, characterized in that, The first gating circuit includes a forward voltage gating branch and a reverse voltage gating branch; When the forward voltage selection branch is closed and the reverse voltage selection branch is open, the voltage source (100) outputs a forward calibration voltage to the device under test; When the forward voltage selection branch is open and the reverse voltage selection branch is closed, the voltage source (100) outputs a reverse calibration voltage to the device under test.

4. The calibration device as described in claim 2, characterized in that, The second gating circuit includes a forward current gating branch and a reverse current gating branch; When the forward current selection branch is closed and the reverse current selection branch is open, the current source (200) outputs a forward calibration current to the device under test; When the forward current selection branch is open and the reverse current selection branch is closed, the current source (200) outputs a reverse calibration current to the device under test.

5. The calibration device as described in claim 2, characterized in that, The calibration device includes an output port group for connecting to the device under test. The output port group includes an AC power port group, a neutral wire connection port, and a DC power port group. The DC power port group includes a first positive port (DC1+), a first negative port (DC1-), a second positive port (DC2+), and a second negative port (DC2-). The first positive port (DC1+) and the first negative port (DC1-) form a first DC power supply circuit, and the second positive port (DC2+) and the second negative port (DC2-) form a second DC power supply circuit. The AC power port group includes three phase interfaces, and a phase-to-phase reverse connection circuit is provided between the three phase interfaces.

6. The calibration apparatus as described in claim 5, characterized in that, The three phase interfaces include interface R, interface S and interface T. The phase-to-phase reverse connection circuit includes a reverse connection switch (KZ22). Interface R is connected to interface S through the reverse connection switch (KZ22).

7. The calibration apparatus as described in claim 5, characterized in that, The switching circuit module (300) includes a first output terminal block (S1) and a second output terminal block (S2). The first output terminal block (S1) is electrically connected to the AC power port group, the first positive port (DC1+), and the second positive port (DC2+). The second output terminal block (S2) is electrically connected to the AC power port group, the neutral connection port, the first negative port (DC1-), and the second negative port (DC2-).

8. The calibration apparatus as described in claim 7, characterized in that, The calibration device also includes a control circuit (400) and an aluminum-cased resistor, which is used to discharge electrical energy from the device under test. The aluminum-cased resistor is connected between the first output terminal block (S1) and the second output terminal block (S2). The control circuit (400) is electrically connected to the aluminum-cased resistor and is used to control the aluminum-cased resistor to work after receiving the voltage calibration completion signal.

9. The calibration apparatus as described in claim 2, characterized in that, The first selection circuit includes a first relay (KZ1), a second relay (KZ2), a third relay (KZ3), a fourth relay (KZ4), a first fuse (FU3), and a second fuse (FU4). The positive terminal of the voltage source (100) is electrically connected to the first terminal of the first relay (KZ1) and the first terminal of the third relay (KZ3), respectively. The negative terminal of the voltage source (100) is electrically connected to the first terminal of the second relay (KZ2) and the first terminal of the fourth relay (KZ4), respectively. The second terminal of the first relay (KZ1) and the second terminal of the second relay (KZ2) are electrically connected to the AC terminal and the positive terminal of the device under test through the first fuse (FU3), respectively. The second terminal of the third relay (KZ3) and the second terminal of the fourth relay (KZ4) are electrically connected to the AC terminal, the neutral terminal, and the negative terminal of the device under test through the second fuse (FU4), respectively.

10. The calibration apparatus as described in claim 2, characterized in that, The second selection circuit includes a fifth relay (KZ5), a sixth relay (KZ6), a seventh relay (KZ7), and an eighth relay (KZ8). The positive terminal of the current source (200) is electrically connected to the first terminal of the fifth relay (KZ5) and the first terminal of the seventh relay (KZ7), respectively. The negative terminal of the current source (200) is electrically connected to the first terminal of the sixth relay (KZ6) and the first terminal of the eighth relay (KZ8), respectively. The second terminal of the fifth relay (KZ5) and the second terminal of the sixth relay (KZ6) are electrically connected to the AC terminal and the positive terminal of the device under test, respectively. The second terminal of the seventh relay (KZ7) and the second terminal of the eighth relay (KZ8) are electrically connected to the AC terminal, the neutral terminal, and the negative terminal of the device under test, respectively.

11. The calibration apparatus as claimed in claim 1, characterized in that, The calibration device further includes a control circuit (400), which is electrically connected to the switching circuit module (300) and is used to control the operation of the switching circuit module (300). The control circuit (400) is also connected to the detection circuit. Specifically, the control circuit (400) is used to control the switching circuit module (300) to work according to the actual voltage output by the device under test detected by the detection circuit. After receiving the voltage calibration completion signal, the control circuit module (300) switches the connection between the voltage source (100) and the device under test to disconnect. And when a voltage safety signal is received, the switching circuit module (300) is controlled to switch the connection between the current source (200) and the device under test.

12. The calibration apparatus according to any one of claims 1-11, characterized in that, The calibration device further includes an isolation circuit, the output of which is electrically connected to the input of the voltage source (100) and the current source (200), respectively, and the input of which is used to be electrically connected to an external AC power supply.

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