A current verification device and method

Abstract

The application discloses a current verification device and method, and belongs to the technical field of current verification. The device comprises a control unit, a direct current power supply, an adjustable direct current boost circuit, an adjustable inverter circuit and a sampling feedback circuit connected with the control unit. The adjustable direct current boost circuit boosts and adjusts the direct current power supply to obtain a direct current voltage. The adjustable inverter circuit is used for inverting and adjusting the direct current voltage to obtain an alternating current voltage. The sampling feedback circuit is used for collecting a sampling current passing through a device to be verified and sending the sampling current to the control unit. The control unit is used for judging the sampling current, adjusting the adjustable direct current boost circuit according to a judgment result to adjust the direct current voltage, or adjusting the on-off of a power tube in the adjustable inverter circuit according to the judgment result to adjust the alternating current voltage. The application adopts a circuit structure and a thought of boosting first and then inverting to realize multi-layer accurate control and improve verification accuracy.

Description

Technical Field

[0001] This invention relates to a current verification device and method, belonging to the field of current verification technology. Background Technology

[0002] Current calibration devices are primarily used for measuring and calibrating current signals, and are widely used in power systems, industrial automation, instrumentation, and other fields. Their core function is to ensure the accuracy of current measurements and guarantee the normal operation of equipment. With the increasing complexity of power systems and the rising demands for accuracy in current measurements, coupled with the emergence of Industry 4.0 and smart manufacturing, even higher accuracy in current measurement is required.

[0003] Currently, the accuracy of portable current calibration devices is generally not high, so how to improve the accuracy of portable current calibration devices is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a current verification device and method, which solves the problem of low current verification accuracy in the prior art when using a current verification device for current verification.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a current verification device, comprising a control unit, a DC power supply, an adjustable DC boost circuit, an adjustable inverter circuit, and a sampling feedback circuit, all connected to the control unit.

[0007] An adjustable DC boost circuit is used to boost the electrical signal provided by the DC power supply to obtain a DC voltage; it is also used to adjust the magnitude of the DC voltage according to the control command of the control unit.

[0008] An adjustable inverter circuit is used to invert the DC voltage output by the adjustable DC boost circuit to obtain an AC voltage; it is also used to adjust the magnitude of the AC voltage according to the control command of the control unit; and it is also used to output the AC voltage to the device to be tested for current verification.

[0009] The sampling feedback circuit is used to collect the sampling current passing through the device to be calibrated and send it to the control unit;

[0010] The control unit is used to verify the sampling current according to the target current required by the device to be verified. If the sampling current does not meet the preset verification requirements, the control unit controls the adjustable DC boost circuit to adjust the magnitude of the DC voltage or controls the adjustable inverter circuit to adjust the magnitude of the AC voltage.

[0011] Furthermore, the adjustable DC boost circuit includes a boost module and a voltage regulation module;

[0012] The boost module includes an EG1164 chip, a MOSFET Q6, a MOSFET Q7, and a transistor Q8. The base of transistor Q8 is connected to the CP pin of the EG1164 chip, the emitter of transistor Q8 is connected to the first power supply, and the collector of transistor Q8 is connected to the SDLIN pin of the EG1164 chip. The drain of MOSFET Q6 is connected to the VS pin of the EG1164 chip, the gate of MOSFET Q6 is connected to the HO pin of the EG1164 chip, and the source of MOSFET Q6 is connected to the SDHIN pin of the EG1164 chip. The drain of MOSFET Q7 is connected to the VS pin of the EG1164 chip, the gate of MOSFET Q7 is connected to the LO pin of the EG1164 chip, and the source of MOSFET Q7 is connected to the SDLIN pin of the EG1164 chip.

[0013] The voltage regulation module includes resistor R27, capacitor C23, resistor R30, resistor R31, resistor R32 and digital potentiometer U1;

[0014] Resistors R31 and R32 are connected in parallel to form the first adjustment module. The first end of the first adjustment module is grounded, and the second end of the first adjustment module is connected to the FB pin of the EG1164 chip. The second end of the first adjustment module is also connected to the L pin of the digital potentiometer U1.

[0015] Resistor R27 and capacitor C23 are connected in series and then in parallel with resistor R30 to form a second regulation module, which is used to output the DC voltage. The first end of the second regulation module is connected to the second end of the first regulation module, and the second end of the second regulation module is connected to the source of MOS power transistor Q6.

[0016] The L pin of the digital potentiometer U1 is connected to the FB pin of the EG1164 chip.

[0017] Furthermore, the adjustable DC boost circuit also includes a voltage regulator chip U4, a series voltage divider module, a loop operational amplifier feedback module, a voltage regulator and filter module, an energy storage voltage regulator module, a current limiting protection module, a unidirectional protection module, a first power transistor protection module, and a second power transistor protection module;

[0018] The voltage regulator chip U4 converts the 12V DC power supply to a 3.3V DC power supply to power the REF pin of the EG1164 chip;

[0019] A series voltage divider module is positioned between the DC power supply and the EN pin of the EG1164 chip to provide a high level to the EN pin;

[0020] The loop operational amplifier feedback module includes a resistor R25 and a capacitor C22. One end of the resistor R25 is connected in series with the capacitor C22 and then connected to the EPRO pin of the EG1164 chip. The other end of the resistor R25 is connected to the FB pin of the EG1164 chip.

[0021] The voltage regulation and filtering module is used to regulate and filter the outputs of the voltage regulator chips U4 and EG1164;

[0022] Energy storage voltage regulator modules are used to store and regulate the voltage of DC power supplies.

[0023] The current limiting protection module is used to provide current limiting protection for the EG1164 chip;

[0024] The unidirectional protection module is used to provide DC reverse power protection for the EG1164 chip;

[0025] The first power transistor protection module is used to protect the MOSFET power transistor Q6, and the second power transistor protection module is used to protect the MOSFET power transistor Q7.

[0026] Furthermore, the series voltage divider module includes a voltage divider resistor R18 and a voltage divider resistor R22. The voltage divider resistor R18 is disposed between the DC power supply and the EN pin of the EG1164 chip, and one end of the voltage divider resistor R22 is connected to the EN pin of the EG1164 chip, while the other end of the voltage divider resistor R22 is grounded.

[0027] Furthermore, the voltage regulation and filtering module includes capacitors C25, C13, C14, C15, C16, and C17. One end of capacitor C25 is grounded, and the other end of capacitor C25 is connected to the output terminal of voltage regulator chip U4 and the REF pin of EG1164 chip, respectively. One end of capacitor C13 is grounded, and the other end of capacitor C13 is connected to the REF pin of EG1164 chip. One end of capacitor C14 is grounded, and the other end of capacitor C14 is connected to the SS pin of EG1164 chip. The two ends of capacitor C15 are connected to the VS pin and VB pin of EG1164 chip, respectively. One end of capacitor C16 is grounded, and the other end of capacitor C16 is connected to the CP pin of EG1164 chip, respectively. The two ends of capacitor C17 are connected to the VCC pin and COM pin of EG1164 chip, respectively.

[0028] The energy storage and voltage regulation module includes capacitors C10, C11, and C12 connected in parallel, and the DC power supply is grounded through the energy storage and voltage regulation module.

[0029] The current limiting protection module includes a current limiting resistor R17 connected in series between the DC power supply and the VCC pin of the EG1164 chip.

[0030] The unidirectional protection module includes a diode D6, and the VB pin of the EG1164 chip is connected to the DC power supply after being connected in reverse series with the diode D6.

[0031] The first power transistor protection module includes resistors R19 and R20 and diode D7. The gate of the MOS power transistor Q6 is connected to the HO pin of the EG1164 chip after series with resistor R19 and diode D7. The drain of the MOS power transistor Q6 is connected to the SDHIN pin of the EG1164 chip after series with resistor R20.

[0032] The second power transistor protection module includes resistors R23 and R24 and diode D8. Resistor R23 and diode D8 are connected in series and then in parallel with resistor R24. The second power transistor protection module is located between the gate of MOS power transistor Q7 and the LO pin of EG1164 chip.

[0033] Furthermore, the adjustable inverter circuit includes a driver board U2, a common-mode inductor L1, MOS power transistors Q1, Q2, Q3, and Q4, a digital potentiometer U5, resistors R1 and R2;

[0034] MOS power transistors Q1, Q2, Q3, and Q4 form a bridge inverter circuit; the driver board U2 is connected to the gates of MOS power transistors Q1, Q3, Q2, and Q4 respectively through different interfaces.

[0035] The output terminal of the bridge inverter circuit is connected in series with a common-mode inductor L1, and the output terminal of the common-mode inductor L1 is used to output AC voltage. The common-mode inductor L1 includes a first winding and a second winding wound on the same magnetic core. The first winding is connected to the drive board U2, the source of MOS power transistor Q1 and the drain of MOS power transistor Q3, respectively. The second winding is connected to the drive board U2, the source of MOS power transistor Q2 and the drain of MOS power transistor Q4, respectively.

[0036] The driver board U2 controls the switching on and off of MOS power transistors Q1 and Q3 to achieve the conversion of AC voltage polarity; the driver board U2 controls the on and off time and ratio of MOS power transistors Q2 and Q4 by outputting PWM waves to adjust the magnitude of AC voltage.

[0037] The digital potentiometer U1 is connected to ground via a series resistor R1, and the series resistor R2 is connected to the output terminal of the common-mode inductor L1 to form a feedback module. The driver board U2 obtains the AC voltage output from the inverter circuit from the feedback module, corrects the PWM wave according to the output AC voltage, and realizes feedback regulation of the AC voltage according to the corrected PWM wave.

[0038] Furthermore, each of the MOS power transistors Q1, Q2, Q3, and Q4 is equipped with its own power transistor protection module; the driver board U2 is connected to the gate signal of each MOS power transistor through the power transistor protection module.

[0039] The power transistor protection module includes a first protection resistor, a second protection resistor, and a protection diode. The first protection resistor and the protection diode are connected in parallel and then connected to the gate of the corresponding MOS power transistor. At the same time, the second protection resistor is connected in series and then connected to the source of the corresponding MOS power transistor.

[0040] Furthermore, the preset verification requirement is that the ratio 'a' of the sampling current to the target current must meet the following requirements:

[0041] 0.99≤a≤1.01.

[0042] In a second aspect, the present invention provides a current verification method based on the current verification device according to any one of the first aspects, executed by the control unit, comprising:

[0043] In response to the detection of the connected device to be verified, the target current value required by the device to be verified is obtained;

[0044] Obtain the sampled current passing through the device to be tested from the sampling feedback circuit;

[0045] Calculate the ratio 'a' between the sampled current and the target current, and perform the following steps based on the value of 'a' until 0.99 ≤ a ≤ 1.01:

[0046] If 0.9≤a<0.99 or 1.01<a≤1.1, then adjust the on / off state of the power transistor in the adjustable inverter circuit, reacquire the sampling current, recalculate the ratio a of the sampling current to the target current, and control the adjustable DC boost circuit to adjust the magnitude of the DC voltage or control the adjustable inverter circuit to adjust the magnitude of the AC voltage based on the value of a.

[0047] If a < 0.9 or a > 1.1, the adjustable DC boost circuit is adjusted to reacquire the sampling current, and the ratio a of the sampling current to the target current is recalculated. Based on the value of a, the adjustable DC boost circuit is controlled to adjust the magnitude of the DC voltage, or the adjustable inverter circuit is controlled to adjust the magnitude of the AC voltage.

[0048] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0049] This invention provides a current calibration device and method that employs a circuit structure and approach of boosting and then inverting the voltage. This allows for further control of the output during both the boosting and inversion processes, resulting in higher accuracy of the output power supply and thus improved current calibration precision. Furthermore, the boost-and-invert approach yields a wide-range adjustable AC power supply. This allows for control over the magnitude of the DC boost at the front end, eliminating the need for directly boosting the DC to 400V as in existing technologies. Instead, the output can be adjusted over a wide range according to specific needs, improving conversion efficiency and extending the operating time of the portable current calibration device. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of a current verification device provided in Embodiment 2;

[0051] Figure 2 This is a schematic diagram of the DC boost circuit provided in Example 2;

[0052] Figure 3 This is a schematic diagram of the inverter circuit provided in Example 2;

[0053] Figure 4 This is a schematic diagram of the AC / DC conversion control circuit provided in Embodiment 2;

[0054] Figure 5 This is a flowchart of the current verification device provided in Embodiment 2. Detailed Implementation

[0055] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0056] Example 1

[0057] This embodiment provides a current verification device, including a control unit, a DC power supply, an adjustable DC boost circuit, an adjustable inverter circuit, and a sampling feedback circuit, all connected to the control unit.

[0058] An adjustable DC boost circuit is used to boost the electrical signal provided by the DC power supply to obtain a DC voltage; it is also used to adjust the magnitude of the DC voltage according to the control command of the control unit.

[0059] An adjustable inverter circuit is used to invert the DC voltage output by the adjustable DC boost circuit to obtain an AC voltage; it is also used to adjust the magnitude of the AC voltage according to the control command of the control unit; and it is also used to output the AC voltage to the device to be tested for current verification.

[0060] The sampling feedback circuit is used to collect the sampling current passing through the device to be calibrated and send it to the control unit;

[0061] The control unit is used to verify the sampling current according to the target current required by the device to be verified. If the sampling current does not meet the preset verification requirements, the control unit controls the adjustable DC boost circuit to adjust the magnitude of the DC voltage or controls the adjustable inverter circuit to adjust the magnitude of the AC voltage.

[0062] This invention employs a circuit structure and approach of boosting voltage before inversion. This allows for further control of the output during both the boosting and inversion processes, resulting in higher accuracy of the current calibration device's output power and thus improved current calibration precision. Furthermore, by using this boosting-before-inversion approach, the resulting AC voltage is a wide-range adjustable AC power supply. This allows for control over the magnitude of the DC boost at the front end, eliminating the need for directly boosting the DC to 400V as in existing technologies. Instead, the output can be adjusted wide-range according to specific needs, improving conversion efficiency and extending the operating time of the portable current calibration device.

[0063] Example 2

[0064] like Figure 1 As shown, this embodiment provides a current verification device, including a control unit (specifically an MCU control center in this embodiment), a sampling feedback circuit, an adjustable DC boost circuit, an adjustable inverter circuit, and a DC power supply, as well as a mobile APP.

[0065] MCU stands for Micro Control Unit. APP stands for Application Software.

[0066] The MCU control center primarily relies on an ARM chip to control the system. The ARM chip selects the output power mode, determining whether the device under test (DUT) will undergo AC or direct calibration. It adjusts the resistance of the voltage regulation module in the DC-DC boost circuit to control the voltage boost. The ARM chip also regulates the output AC voltage by switching the power transistors in the adjustable inverter circuit. The sampling feedback circuit uses the ARM chip to collect the current sampled through the sampling resistor (the DUT). Based on the sampled current, it further adjusts the voltage regulation module and the power transistors in the adjustable inverter circuit to ensure more accurate output current. A mobile app connects to the MCU control center via Bluetooth. All commands can be sent and received from the app, and information such as the output current of the calibration device can also be displayed on the app. This avoids direct contact between operators and the calibration device, reducing manual operation and making the overall operation safer and more efficient, thus automating and intelligently transforming the portable current calibration device.

[0067] like Figure 2 As shown, in the adjustable DC boost circuit of this embodiment, the EG1164 chip (i.e. Figure 2U3 in the circuit serves as the control chip for the adjustable DC-DC boost circuit. The roles of each component in the adjustable DC-DC boost circuit are as follows: Voltage regulator chip U4 converts the 12V DC power supply to 3.3V DC power, supplying power to the VCC pin of the EG1164 chip. One end of capacitor C25 is grounded, and the other end is connected to the output terminal of voltage regulator chip U4 and the REF pin of the EG1164 chip, thus providing voltage regulation and filtering. The EG1164 chip, as the core component of the adjustable DC-DC boost circuit, controls the circuit's operation. Capacitors C10, C11, and C12 are connected in parallel with the DC power supply, providing energy storage and voltage regulation. Resistor R17 is connected in series between the adjustable DC power supply and the COM pin of the EG1164 chip, providing current limiting protection. Resistors R18 and R22 are connected in series to divide the voltage and are then connected to the EN pin of the EG1164 chip. This voltage divider provides a high level to the EN pin of the EG1164 chip, enabling the EG1164 chip to operate. One end of capacitor C13 is grounded, and the other end is connected to the REF pin of the EG1164 chip. One end of capacitor C14 is grounded, and the other end is connected to the SS pin of the EG1164 chip. The two ends of capacitor C15 are connected to the VS and VB pins of the EG1164 chip, respectively. One end of capacitor C16 is grounded, and the other end is connected to the CP pin of the EG1164 chip. The two ends of capacitor C17 are connected to the VCC and COM pins of the EG1164 chip, respectively. These capacitors all serve as voltage regulators and filters. Diode D6 is connected in series between the DC power supply and the VB pin of the EG1164 chip. Here, the current can only conduct in one direction, preventing the EG1164 chip from burning out if the positive and negative terminals of the DC power supply are reversed, thus providing protection. Resistor R19 and diode D7 are connected in series and then in parallel with resistor R20, which protects MOS power transistor Q6. MOS power transistor is a metal-oxide-semiconductor field-effect transistor. Resistor R23 and diode D8 are connected in series and then in parallel with resistor R24, which protects MOS power transistor Q7.The switching of MOSFETs Q6 and Q7 causes the DC power supply voltage to rise. Resistor R20 is connected in series between the high-level output and the SDHIN pin of the EG1164 chip. Resistor R26, connected in series with constantan wire R29, is then connected in series with the low-level output and the SDLIN pin of the EG1164 chip. Resistor R28 is connected in series with MOSFET Q8 to provide feedback on the current flowing through MOSFETs Q6 and Q7. When the current flowing through the MOSFETs exceeds a threshold, the EG1164 chip will turn off the MOSFETs, thus providing circuit protection. Resistor R25 and capacitor C22 are connected in series as a loop operational amplifier feedback module. One end of resistor R25, after being connected in series with capacitor C22, is connected to the EPRO pin of the EG1164 chip, and the other end of resistor R25 is connected to the FB pin of the EG1164 chip. Resistor R27 and capacitor C23 are connected in series, then in parallel with resistor R30. This parallel connection is then combined with a combination of resistors R31 and R32, and the output resistor of digital potentiometer U1. The output DC voltage is changed by adjusting the output resistance of digital potentiometer U1 through the microcontroller, thereby changing the output voltage. Capacitors C18, C19, and C20 are connected in parallel with the output power supply, acting as voltage regulators and filters for the output voltage, providing a stable DC source for the subsequent circuits.

[0068] exist Figure 2 In the middle, the EG1164 chip (i.e. Figure 2 The explanations of each port in U3 are as follows:

[0069] REF pin, 3.3V reference voltage pin;

[0070] EN pin, enable control pin;

[0071] The SD pin, when high, is the control terminal for shutting down the PWM output;

[0072] SS pin, soft-start control pin;

[0073] VSS pin, signal ground pin;

[0074] CP pin, oscillator capacitor pin;

[0075] The ERRO pin is the output port of the voltage loop op-amp.

[0076] FB pin, the negative input port of the voltage loop op-amp;

[0077] SDLIN pin, the input port of the low-side MOSFET current comparator;

[0078] The LO pin is the first power output control pin, which controls the on / off state of the low-side MOSFET.

[0079] The COM pin, the first high-side floating ground, is used to connect to the gate of the high-side MOSFET.

[0080] VCC pin, power input pin;

[0081] SDHIN pin, the input port of the high-side MOSFET current comparator;

[0082] The VS pin, the second high-side floating ground, is used to connect to the drain of the high-side MOSFET;

[0083] VB pin, high-side floating power supply, is used to provide floating power to the high-side MOSFET;

[0084] The HO pin is the second power output control pin, which controls the output port that controls the on / off state of the high-side MOSFET.

[0085] Figure 2 The pin explanations for each pin of the digital potentiometer U1 are as follows:

[0086] The SCLK pin is the SPI clock line, the DIN pin is the SPI input line, the CS# pin is the chip select, the VDD pin is the positive power input, the GND pin is the ground, the H pin is the high-side output, the W pin is the sliding end output, and the L pin is the low-side output.

[0087] Figure 3 The pin explanations for digital potentiometer U5 are the same as those for digital potentiometer U1, and will not be repeated here.

[0088] Figure 4 The pin explanations for each pin in the digital potentiometer U6 are as follows:

[0089] The OUT pin is the output pin, the VCC pin is the power input pin, the GND pin is the ground, the VP pin is the positive terminal of the differential input signal, and the VN pin is the negative terminal of the differential input signal.

[0090] Figure 2 The specific connection relationships of each component are described below:

[0091] The adjustable DC boost circuit includes an EG1164 chip, a voltage regulator chip U4, a series voltage divider module, a boost module, a loop operational amplifier feedback module, and a voltage regulation module.

[0092] The voltage regulator chip U4 connects the DC power supply and the power input terminal of the EG1164 chip to regulate the voltage of the DC power supply to a first set voltage. In this embodiment, the first set voltage is 3.3V, that is, the 12V DC power supply is converted into a 3.3V DC power supply to power the REF pin of the EG1164 chip.

[0093] The series voltage divider module is placed between the DC power supply and the EN pin of the EG1164 chip to provide a high level to the EN pin;

[0094] The boost module includes an EG1164 chip, MOSFETs Q6 and Q7, and a transistor Q8. The base of transistor Q8 is connected to the CP pin of the EG1164 chip, the emitter of transistor Q8 is connected to the +3.3V power supply, and the collector of transistor Q8 is connected to the SDLIN pin of the EG1164 chip. The drain of MOSFET Q6 is connected to the VS pin of the EG1164 chip, the gate of MOSFET Q6 is connected to the HO pin of the EG1164 chip, and the source of MOSFET Q6 is connected to the SDHIN pin of the EG1164 chip. The drain of MOSFET Q7 is connected to the VS pin of the EG1164 chip, the gate of MOSFET Q7 is connected to the LO pin of the EG1164 chip, and the source of MOSFET Q7 is connected to the SDLIN pin of the EG1164 chip.

[0095] The loop operational amplifier feedback module includes a resistor R25 and a capacitor C22. One end of the resistor R25 is connected in series with the capacitor C22 and then connected to the EPRO pin of the EG1164 chip. The other end of the resistor R25 is connected to the FB pin of the EG1164 chip.

[0096] The voltage regulation module includes resistor R27, capacitor C23, resistor R30, resistor R31, resistor R32, and digital potentiometer U1.

[0097] Resistors R31 and R32 are connected in parallel to form the first adjustment module. The first end of the first adjustment module is grounded, and the second end of the first adjustment module is connected to the FB pin of the EG1164 chip. The second end of the first adjustment module is also connected to the L pin of the digital potentiometer U1.

[0098] Resistor R27 and capacitor C23 are connected in series and then in parallel with resistor R30 to form a second regulation module, which is used to output the DC voltage. The first end of the second regulation module is connected to the second end of the first regulation module, and the second end of the second regulation module is connected to the source of MOS power transistor Q6.

[0099] The L pin of the digital potentiometer U1 is connected to the FB pin of the EG1164 chip.

[0100] The series voltage divider module includes voltage divider resistors R18 and R22. Voltage divider resistor R18 is placed between the DC power supply and the EN pin of the EG1164 chip. One end of voltage divider resistor R22 is connected to the EN pin of the EG1164 chip, and the other end of voltage divider resistor R22 is grounded.

[0101] The adjustable DC boost circuit also includes a voltage regulator and filter module, an energy storage voltage regulator module, a current limiting protection module, a unidirectional protection module, a first power transistor protection module, and a second power transistor protection module;

[0102] The voltage regulation and filtering module is used to regulate and filter the outputs of the voltage regulator chips U4 and EG1164;

[0103] Energy storage voltage regulator modules are used to store and regulate the voltage of DC power supplies.

[0104] The current limiting protection module is used to provide current limiting protection for the EG1164 chip;

[0105] The unidirectional protection module is used to prevent damage to the EG1164 chip caused by reverse connection of the positive and negative terminals of the DC power supply;

[0106] The first power transistor protection module is used to protect the MOSFET power transistor Q6, and the second power transistor protection module is used to protect the MOSFET power transistor Q7.

[0107] The voltage regulation and filtering module includes capacitors C25, C13, C14, C15, C16, and C17. One end of capacitor C25 is grounded, and the other end of capacitor C25 is connected to the output terminal of voltage regulator chip U4 and the REF pin of EG1164 chip. One end of capacitor C13 is grounded, and the other end of capacitor C13 is connected to the REF pin of EG1164 chip. One end of capacitor C14 is grounded, and the other end of capacitor C14 is connected to the SS pin of EG1164 chip. The two ends of capacitor C15 are connected to the VS pin and VB pin of EG1164 chip, respectively. One end of capacitor C16 is grounded, and the other end of capacitor C16 is connected to the CP pin of EG1164 chip. The two ends of capacitor C17 are connected to the VCC pin and COM pin of EG1164 chip, respectively.

[0108] The energy storage voltage regulator module includes capacitors C10, C11, and C12 connected in parallel, and the DC power supply is grounded through the energy storage voltage regulator module.

[0109] The current limiting protection module includes a current limiting resistor R17 connected in series between the DC power supply and the VCC pin of the EG1164 chip.

[0110] The unidirectional protection module includes diode D6. The VB pin of the EG1164 chip is connected in reverse series with diode D6 and then connected to the DC power supply.

[0111] The first power transistor protection module includes resistors R19 and R20 and diode D7. The gate of MOS power transistor Q6 is connected to the HO pin of the EG1164 chip after series resistor R19 and diode D7. The drain of MOS power transistor Q6 is connected to the SDHIN pin of the EG1164 chip after series resistor R20.

[0112] The second power transistor protection module includes resistors R23 and R24 and diode D8. Resistor R23 and diode D8 are connected in series and then in parallel with resistor R24. The second power transistor protection module is located between the gate of MOS power transistor Q7 and the LO pin of EG1164 chip.

[0113] Based on the connection relationship of the adjustable DC boost circuit described above, the operating principle of the adjustable DC boost circuit in this embodiment can be described as follows: The 12V DC power supply is converted into a 3.3V DC power supply by the voltage regulator chip U4, which powers the REF pin between the LO pins of the EG1164 chip. The voltage regulator chip U4 in this embodiment is specifically model AMS1117-3.3. The 12V DC power supply is divided to 2V by two voltage divider resistors of 100K and 20K, keeping the EN pin of the EG1164 chip high, thus putting the EG1164 chip into operation. The 12V DC power supply is boosted through a power inductor. The EG1164 chip controls the switching of the high-side and low-side MOSFETs by outputting a PWM wave, thereby achieving DC boost. The microcontroller controls the digital potentiometer U1 to adjust the control resistor, thereby controlling the output DC voltage. Here, an adjustable DC output from 10V to 250V can be achieved. In this embodiment, the digital potentiometer U1 is specifically model TPL0501-100DCNR. For the output voltage, a 51K resistor is used to measure the current through the MOSFET power transistor. When the current exceeds the threshold, the boost power module U3 shuts down both the high-side and low-side MOSFET power transistors, causing the entire adjustable DC boost circuit to stop working, thus providing protection.

[0114] like Figure 3As shown, in the adjustable inverter circuit of this embodiment, the driver board U2 (composed of chips EG8010 and IR2110S) is used as the control center of the adjustable inverter circuit to control the voltage magnitude and polarity of the inverter output power supply (i.e., the AC voltage output by the inverter circuit). It also has an overcurrent protection function. When the current through the MOS power transistor is too large, the driver board U2 will turn off the MOS power transistor to protect the circuit. Resistor R4 and diode D1 are connected in parallel and then in series with the gate of driver board U2 and MOS power transistor Q1. Resistor R6 is connected in series between the source and gate of MOS power transistor Q1. Resistor R8 and diode D4 are connected in parallel and then in series with the gate of driver board U2 and MOS power transistor Q3. Resistor R10 is connected in series between the source and gate of MOS power transistor Q3, providing protection for MOS power transistors Q1 and Q3. Driver board U2 controls the polarity switching of MOS power transistors Q1 and Q3. When MOS power transistor Q1 is on and MOS power transistor Q3 is off, the second pin of common mode inductor L1 is always at a high level, and the voltage at the L end is higher than the voltage at the N end. When MOS power transistor Q1 is off and MOS power transistor Q3 is on, the second pin of common mode inductor L1 is always at a low level, and the voltage at the L end is lower than the voltage at the N end. Resistor R5 and diode D2 are connected in parallel. The resistor R7 is connected in series with the gate of the MOS power transistor Q2 and the drive board U2. The resistor R9 and diode D3 are connected in parallel and then connected in series with the gate of the drive board U2 and the MOS power transistor Q4. The resistor R11 is connected in series with the source and gate of the MOS power transistor Q4 to protect the MOS power transistors Q2 and Q4. The drive board U2 controls the voltage by controlling the MOS power transistors Q2 and Q4. When the MOS power transistor Q2 is on and the MOS power transistor Q4 is off, the first pin of the common mode inductor L1 is at a high level. When the MOS power transistor Q2 is off and the MOS power transistor Q4 is on, the first pin of the common mode inductor L1 is at a low level. The drive board U2 outputs a PWM wave to control the on and off time and percentage of the MOS power transistors Q2 and Q4, thereby adjusting the output AC voltage. The output AC voltage is filtered and regulated into a stable AC power supply through a power inductor and capacitor; the digital potentiometer U1 is grounded after being connected in series with resistor R1, and the series resistor R2 is connected to the output terminal of the common mode inductor L1 to form a feedback module. The driver board U2 obtains the information of the output AC voltage by reading the information of the feedback circuit, and then corrects the PWM wave to further adjust the output AC voltage to ensure that the required voltage is obtained.

[0115] Figure 3 The specific connection relationships of each component are described below:

[0116] The adjustable inverter circuit includes a driver board U2, a feedback module, a common-mode inductor L1, MOS power transistors Q1, Q2, Q3, and Q4.

[0117] MOS power transistors Q1, Q2, Q3, and Q4 form a bridge inverter circuit; the driver board U2 is connected to the gates of MOS power transistors Q1, Q3, Q2, and Q4 respectively through different interfaces.

[0118] The output of the bridge inverter circuit is connected in series with a common-mode inductor L1. The output of the common-mode inductor L1 is used to output AC voltage. The common-mode inductor L1 includes a first winding and a second winding wound on the same magnetic core. The first winding is connected to the drive board U2, the source of MOS power transistor Q1 and the drain of MOS power transistor Q3, respectively. The second winding is connected to the drive board U2, the source of MOS power transistor Q2 and the drain of MOS power transistor Q4, respectively.

[0119] The driver board U2 controls the switching on and off of MOS power transistors Q1 and Q3 to achieve the conversion of AC voltage polarity; the driver board U2 controls the on and off time and ratio of MOS power transistors Q2 and Q4 by outputting PWM waves to adjust the magnitude of AC voltage.

[0120] The digital potentiometer U1 is connected to ground via a series resistor R1, and the series resistor R2 is connected to the output terminal of the common-mode inductor L1 to form a feedback module. The driver board U2 obtains the AC voltage output from the inverter circuit from the feedback module, corrects the PWM wave according to the output AC voltage, and realizes feedback regulation of the AC voltage according to the corrected PWM wave.

[0121] The adjustable inverter circuit also includes a third power transistor protection module, a fourth power transistor protection module, a fifth power transistor protection module, and a sixth power transistor protection module.

[0122] The third power transistor protection module includes resistor R4, diode D1 and resistor R6. Resistor R4 and diode D1 are connected in parallel and then connected in series with the driver board U2 and the gate of MOS power transistor Q1. Resistor R6 is connected in series between the source and gate of MOS power transistor Q1.

[0123] The fourth power transistor protection module includes resistor R5, diode D2 and resistor R7. Resistor R5 and diode D2 are connected in parallel and then connected in series with the driver board U2 and the gate of MOS power transistor Q2. Resistor R7 is connected in series between the source and gate of MOS power transistor Q2.

[0124] The fifth power transistor protection module includes resistor R8, diode D4 and resistor R10. Resistor R8 and diode D4 are connected in parallel and then connected in series with the driver board U2 and the gate of MOS power transistor Q3. Resistor R10 is connected in series between the source and gate of MOS power transistor Q3.

[0125] The sixth power transistor protection module includes resistor R9, diode D3 and resistor R11. Resistor R9 and diode D3 are connected in parallel and then connected in series with the driver board U2 and the gate of MOS power transistor Q4. Resistor R11 is connected in series between the source and gate of MOS power transistor Q4.

[0126] The driver board U2 controls the switching on and off of MOSFETs Q1 and Q3 to achieve AC voltage polarity conversion, including:

[0127] When the driver board U2 controls the MOS power transistor Q1 to be off and the MOS power transistor Q3 to be on, the second pin of the common mode inductor L1 is always at a low level. At this time, the L-terminal voltage of the common mode inductor L1 is lower than the N-terminal voltage.

[0128] Based on the connection relationship of the adjustable inverter circuit described above, the operating principle of the adjustable inverter circuit in this embodiment can be described as follows: A driver board U2, composed of chips EG8010 and IR2110S, serves as the control board to control the on / off state of four MOS power transistors (i.e., MOS power transistors Q1, Q2, Q3, and Q4, specifically model IRF840APBF in this embodiment). Two of the MOS power transistors control the polarity of the output power supply, and the other two control the voltage of the output power supply. The output power supply is converted into standard AC power through a common-mode inductor and capacitor connected in series. A microcontroller controls a digital potentiometer U5 (specifically model TPL0501-100DCNR in this embodiment) to adjust the feedback resistor, further adjusting the output voltage to make the output result more accurate.

[0129] like Figure 4As shown, in the AC / DC conversion control circuit, the state of the dual-channel relay K1 is controlled by a microcontroller to achieve the AC / DC conversion function. Resistor R13 is connected in series in the AC / DC conversion control circuit, serving as a current-limiting protection element in the circuit. Gas discharge tube F1 is connected in parallel between the output terminals J1 and J2 of the AC / DC conversion control circuit to prevent excessive voltage applied to the device under test, thus preventing damage and providing protection. Rectifier bridge D5 converts AC power to DC power, and rectifier bridge D6 is the feedback circuit, converting the detection power from AC to DC. Capacitor C3 is connected in parallel across the DC output terminals of rectifier bridge D6, serving as an energy storage and voltage regulator. Resistor R15 is the sampling resistor. Resistors R14 and R16 are connected in parallel and then in series with resistor R15, providing current-limiting protection. The current amplifier U6 amplifies the current passing through the sampling resistor for easy sampling. The capacitor C4 is connected in parallel to the power supply terminal of the current amplifier U6 to provide filtering and voltage regulation for the power supply of the current amplifier U6. Resistors R21, R22 and R24 serve as current limiting protection.

[0130] The control unit connects to the digital potentiometer U1 in the DC boost circuit via the SPI bus, and controls the output DC voltage by controlling the output resistance of the digital potentiometer U1. The control unit also connects to the digital potentiometer U5 in the inverter circuit via the SPI bus, and controls the output AC voltage by controlling the output resistance of the digital potentiometer U5. The control unit measures the output current through the ADC pin and controls the state of the relay K1 through the I / O port to achieve AC / DC output conversion. The control unit interacts with a mobile APP via Bluetooth module.

[0131] like Figure 5 As shown, the current verification device provided in this embodiment has the following working process:

[0132] Step 1: Microcontroller initialization;

[0133] Step 2: Select the output power mode to confirm whether the device to be calibrated is AC or DC calibrated;

[0134] Step 3: Input the target current value required for the device to be tested;

[0135] Step 4: Adjust the output resistance of the digital potentiometer in the DC boost circuit and the digital potentiometer in the inverter circuit;

[0136] Step 5: Collect the sampling current of the device to be calibrated, and calculate the ratio a of the sampling current to the target current. If 0.99≤a≤1.01, proceed to step 9; otherwise, proceed to step 6.

[0137] Step 6: Determine if 0.9≤a≤1.1 is true. If yes, proceed to step 7; otherwise, proceed to step 8.

[0138] Step 7: Adjust the output resistance of the digital potentiometer in the adjustable inverter circuit, and then proceed to step 5;

[0139] Step 8: Adjust the output resistance of the digital potentiometer in the adjustable DC boost circuit, and then proceed to step 5;

[0140] Step 9: End the process.

[0141] In this embodiment, the DC voltage output by the adjustable DC boost circuit is Vout1 = (1 + R1 / R2) * 1.2, where R1 represents the fixed feedback resistance value in the adjustable DC boost circuit, and R2 represents the output resistance value of the digital potentiometer U1 in the adjustable DC boost circuit; the AC voltage output by the adjustable inverter circuit is Vout2 = (1 + R4 / R3) * 3.3, where R3 represents the fixed feedback resistance value in the adjustable inverter circuit, and R4 represents the output resistance value of the digital potentiometer U5 in the adjustable inverter circuit; taking R3 = 10KΩ and R1 = 200 KΩ as an example, since the operating voltage of the device under test is mostly 3.3V DC or 5V DC, and the withstand voltage of the components used in the device will also be higher than 5V, after setting the current required by the device under test as the target current I0, the inverter circuit is initially set to output 5V AC power. At this time, R4 = 5.15 KΩ and R2 = 63.16 KΩ. The actual sampling current I1 passing through the device under test is measured, and a = When I1 / I0, if 0.99≤a≤1.01 (Formula 1), the output resistance of the two digital potentiometers remains unchanged; when Formula 1 is not true and 0.9≤a≤1.1 (Formula 2), the output resistance R2 of digital potentiometer U1 remains unchanged, and the output resistance R4 of digital potentiometer U5 becomes (500*a-330) / 33KΩ. Then, the next round of sampling and iteration calculation is performed until 0.99≤a≤1.01 (Formula 3); when neither Formula 1 nor Formula 2 is true, the output resistance R2 of digital potentiometer U1 becomes 1200 / (25*a-6)KΩ, and the output resistance R4 of digital potentiometer U5 becomes (500*a-330) / 33KΩ. Then, the next round of sampling and iteration calculation is performed until 0.99≤a≤1.01.

[0142] Example 3

[0143] This embodiment provides a current verification method, executed by the control unit in Embodiment 1 or Embodiment 2, including:

[0144] In response to the detection of the connected device to be verified, the target current value required by the device to be verified is obtained;

[0145] Obtain the sampled current passing through the device to be tested from the sampling feedback circuit;

[0146] Calculate the ratio 'a' between the sampled current and the target current, and perform the following steps based on the value of 'a' until 0.99 ≤ a ≤ 1.01:

[0147] If 0.9≤a<0.99 or 1.01<a≤1.1, then adjust the on / off state of the power transistor in the adjustable inverter circuit, re-acquire the sampling current, recalculate the ratio a of the sampling current to the target current, and control the adjustable DC boost circuit to adjust the magnitude of the DC voltage or control the adjustable inverter circuit to adjust the magnitude of the AC voltage based on the value of a.

[0148] If a < 0.9 or a > 1.1, the adjustable DC boost circuit is adjusted, the sampling current is reacquired, and the ratio a of the sampling current to the target current is recalculated. Based on the value of a, the adjustable DC boost circuit is controlled to adjust the magnitude of the DC voltage, or the adjustable inverter circuit is controlled to adjust the magnitude of the AC voltage.

[0149] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0150] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0151] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0152] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0153] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A current verification device, characterized in that, It includes a control unit, a DC power supply, an adjustable DC boost circuit, an adjustable inverter circuit, and a sampling feedback circuit, all connected to the control unit. An adjustable DC boost circuit is used to boost the electrical signal provided by the DC power supply to obtain a DC voltage; it is also used to adjust the magnitude of the DC voltage according to the control command of the control unit. An adjustable inverter circuit is used to invert the DC voltage output by the adjustable DC boost circuit to obtain an AC voltage; it is also used to adjust the magnitude of the AC voltage according to the control command of the control unit; and it is also used to output the AC voltage to the device to be tested for current verification. The sampling feedback circuit is used to collect the sampling current passing through the device to be calibrated and send it to the control unit; The control unit is used to verify the sampling current according to the target current required by the device to be verified. If the sampling current does not meet the preset verification requirements, the control unit controls the adjustable DC boost circuit to adjust the magnitude of the DC voltage or controls the adjustable inverter circuit to adjust the magnitude of the AC voltage. The adjustable DC boost circuit includes a boost module and a voltage regulation module; The boost module includes an EG1164 chip, a MOSFET Q6, a MOSFET Q7, and a transistor Q8. The base of transistor Q8 is connected to the CP pin of the EG1164 chip, the emitter of transistor Q8 is connected to the first power supply, and the collector of transistor Q8 is connected to the SDLIN pin of the EG1164 chip. The drain of MOSFET Q6 is connected to the VS pin of the EG1164 chip, the gate of MOSFET Q6 is connected to the HO pin of the EG1164 chip, and the source of MOSFET Q6 is connected to the SDHIN pin of the EG1164 chip. The drain of MOSFET Q7 is connected to the VS pin of the EG1164 chip, the gate of MOSFET Q7 is connected to the LO pin of the EG1164 chip, and the source of MOSFET Q7 is connected to the SDLIN pin of the EG1164 chip. The voltage regulation module includes resistor R27, capacitor C23, resistor R30, resistor R31, resistor R32 and digital potentiometer U1; Resistors R31 and R32 are connected in parallel to form the first adjustment module. The first end of the first adjustment module is grounded, and the second end of the first adjustment module is connected to the FB pin of the EG1164 chip. The second end of the first adjustment module is also connected to the L pin of the digital potentiometer U1. Resistor R27 and capacitor C23 are connected in series and then in parallel with resistor R30 to form a second regulation module, which is used to output the DC voltage. The first end of the second regulation module is connected to the second end of the first regulation module, and the second end of the second regulation module is connected to the source of MOS power transistor Q6. The L pin of the digital potentiometer U1 is connected to the FB pin of the EG1164 chip.

2. The current verification device according to claim 1, characterized in that, The adjustable DC boost circuit also includes a voltage regulator chip U4, a series voltage divider module, a loop operational amplifier feedback module, a voltage regulator and filter module, an energy storage voltage regulator module, a current limiting protection module, a unidirectional protection module, a first power transistor protection module, and a second power transistor protection module. The voltage regulator chip U4 converts the 12V DC power supply to a 3.3V DC power supply to power the REF pin of the EG1164 chip; A series voltage divider module is positioned between the DC power supply and the EN pin of the EG1164 chip to provide a high level to the EN pin; The loop operational amplifier feedback module includes a resistor R25 and a capacitor C22. One end of the resistor R25 is connected in series with the capacitor C22 and then connected to the EPRO pin of the EG1164 chip. The other end of the resistor R25 is connected to the FB pin of the EG1164 chip. The voltage regulation and filtering module is used to regulate and filter the outputs of the voltage regulator chips U4 and EG1164; Energy storage voltage regulator modules are used to store and regulate the voltage of DC power supplies. The current limiting protection module is used to provide current limiting protection for the EG1164 chip; The unidirectional protection module is used to provide DC reverse power protection for the EG1164 chip; The first power transistor protection module is used to protect the MOSFET power transistor Q6, and the second power transistor protection module is used to protect the MOSFET power transistor Q7.

3. The current verification device according to claim 2, characterized in that, The series voltage divider module includes a voltage divider resistor R18 and a voltage divider resistor R22. The voltage divider resistor R18 is located between the DC power supply and the EN pin of the EG1164 chip. One end of the voltage divider resistor R22 is connected to the EN pin of the EG1164 chip, and the other end of the voltage divider resistor R22 is grounded.

4. The current verification device according to claim 2, characterized in that, The voltage stabilizing and filtering module includes capacitors C25, C13, C14, C15, C16, and C17. The output terminal of the voltage regulator chip U4 is connected to ground after being connected in series with capacitor C25. The REF pin of the EG1164 chip is connected to ground after being connected in series with capacitor C13; The SS pin of the EG1164 chip is connected to ground after being connected in series with capacitor C14; The CP pin of the EG1164 chip is connected to ground after being connected in series with capacitor C16; The two ends of capacitor C15 are connected to the VS pin and VB pin of the EG1164 chip, respectively; The two ends of capacitor C17 are connected to the VCC pin and the COM pin of the EG1164 chip, respectively; The energy storage and voltage regulation module includes capacitors C10, C11, and C12 connected in parallel, and the DC power supply is grounded through the energy storage and voltage regulation module. The current limiting protection module includes a current limiting resistor R17 connected in series between the DC power supply and the VCC pin of the EG1164 chip. The unidirectional protection module includes a diode D6, and the VB pin of the EG1164 chip is connected to the DC power supply after being connected in reverse series with the diode D6. The first power transistor protection module includes resistors R19 and R20 and diode D7. The gate of the MOS power transistor Q6 is connected to the HO pin of the EG1164 chip after series with resistor R19 and diode D7. The drain of the MOS power transistor Q6 is connected to the SDHIN pin of the EG1164 chip after series with resistor R20. The second power transistor protection module includes resistors R23 and R24 and diode D8. Resistor R23 and diode D8 are connected in series and then in parallel with resistor R24. The second power transistor protection module is located between the gate of MOS power transistor Q7 and the LO pin of EG1164 chip.

5. The current verification device according to claim 1, characterized in that, The adjustable inverter circuit includes a driver board U2, a common-mode inductor L1, MOS power transistors Q1, Q2, Q3, and Q4, a digital potentiometer U5, resistors R1 and R2. MOS power transistors Q1, Q2, Q3, and Q4 form a bridge inverter circuit; the driver board U2 is connected to the gates of MOS power transistors Q1, Q3, Q2, and Q4 respectively through different interfaces. The output terminal of the bridge inverter circuit is connected in series with a common-mode inductor L1, and the output terminal of the common-mode inductor L1 is used to output AC voltage. The common-mode inductor L1 includes a first winding and a second winding wound on the same magnetic core. The first winding is connected to the drive board U2, the source of MOS power transistor Q1 and the drain of MOS power transistor Q3, respectively. The second winding is connected to the drive board U2, the source of MOS power transistor Q2 and the drain of MOS power transistor Q4, respectively. The driver board U2 controls the switching on and off of MOS power transistors Q1 and Q3 to achieve the conversion of AC voltage polarity; the driver board U2 controls the on and off time and ratio of MOS power transistors Q2 and Q4 by outputting PWM waves to adjust the magnitude of AC voltage. The digital potentiometer U1 is connected to ground via a series resistor R1, and the series resistor R2 is connected to the output terminal of the common-mode inductor L1 to form a feedback module. The driver board U2 obtains the AC voltage output from the inverter circuit from the feedback module, corrects the PWM wave according to the output AC voltage, and realizes feedback regulation of the AC voltage according to the corrected PWM wave.

6. The current verification device according to claim 5, characterized in that, Each of the MOS power transistors Q1, Q2, Q3, and Q4 is equipped with its own power transistor protection module; the driver board U2 is connected to the gate signal of each MOS power transistor through the power transistor protection module. The power transistor protection module includes a first protection resistor, a second protection resistor, and a protection diode. The first protection resistor and the protection diode are connected in parallel and then connected to the gate of the corresponding MOS power transistor. At the same time, the second protection resistor is connected in series and then connected to the source of the corresponding MOS power transistor.

7. The current verification device according to claim 1, characterized in that, The preset verification requirement is that the ratio 'a' of the sampling current to the target current must meet the following requirements: 0.99≤a≤1.01。 8. A current verification method based on the current verification device according to any one of claims 1 to 7, characterized in that, Executed by the control unit, including: In response to the detection of the connected device to be verified, the target current value required by the device to be verified is obtained; Obtain the sampled current passing through the device to be tested from the sampling feedback circuit; Calculate the ratio 'a' between the sampled current and the target current, and perform the following steps based on the value of 'a' until 0.99 ≤ a ≤ 1.01: If 0.9≤a<0.99 or 1.01<a≤1.1, then adjust the on / off state of the power transistor in the adjustable inverter circuit, reacquire the sampling current, recalculate the ratio a of the sampling current to the target current, and control the adjustable DC boost circuit to adjust the magnitude of the DC voltage or control the adjustable inverter circuit to adjust the magnitude of the AC voltage based on the value of a. If a < 0.9 or a > 1.1, the adjustable DC boost circuit is adjusted to reacquire the sampling current, and the ratio a of the sampling current to the target current is recalculated. Based on the value of a, the adjustable DC boost circuit is controlled to adjust the magnitude of the DC voltage, or the adjustable inverter circuit is controlled to adjust the magnitude of the AC voltage.

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