Sampling calibration device and calibration method

Abstract

The invention discloses a sampling calibration device and a calibration method, is applied to the field of sampling calibration of power electronic equipment, and aims to solve the problem of inconsistent sampling precision in a full power range caused by nonlinear errors and individual differences in the sampling calibration process of the existing power electronic equipment. A super capacitor is charged through an adjustable high-voltage power supply, then resistors with different resistance values are connected, a circuit of each resistor is controlled by a controllable thyristor, meanwhile, a standard current sensor is connected to each circuit to serve as a comparison reference, and a detected current sensor is connected to a post-stage circuit in series; the measured sensor and the reference sensor provide sampled data to the calibration controller contrl through different paths, and the sampled data are compared and calibrated in the calibration controller; sampling values of the reference sensor and the tested sensor are transmitted to the sampling calibration tool controller, and sampling data of the tested sensor are compared and calibrated through a corresponding algorithm in the sampling calibration tool controller.

Description

Technical Field

[0001] This invention belongs to the field of sampling and calibration of power electronic equipment, and specifically relates to a sampling and calibration device and calibration technology. Background Technology

[0002] Sampling and calibration of power electronic equipment (such as frequency converters, inverters, UPS, photovoltaic inverters, energy storage converters, etc.) is the foundation for ensuring their control accuracy, efficiency, power quality and safe and stable operation.

[0003] Currently, the main sampling calibration method in the industry is hardware calibration plus whole-machine software sampling parameter correction. Hardware calibration involves applying a precise standard source to the sampling board in the analog sampling circuit and adjusting the potentiometer to achieve sampling calibration. However, the accuracy is limited and the production efficiency is low. Whole-machine software sampling parameter correction uses software algorithms to compensate for errors in the hardware links. However, when calibrating the sampling coefficients, due to the non-linearity of sensor sampling accuracy and the differences in charging and discharging of the device itself, the final result is that low power is accurate but high power is inaccurate, or high power is accurate but low power is inaccurate. This means that only range calibration is possible, and accurate full-power full-range sampling cannot be achieved.

[0004] Meanwhile, in the process of shipping large quantities of power electronic equipment, sampling and calibration are basically located in the factory testing stage. During the factory verification process with tight project delivery schedules, a lot of debugging time is wasted on sampling and calibration.

[0005] In summary, the existing technology mainly has the following technical problems:

[0006] A: The problem of inconsistent sampling accuracy across the entire power range due to nonlinear errors and individual differences during the sampling calibration process of power electronic equipment;

[0007] B: The existing calibration process focuses on the whole machine testing stage, which consumes a lot of debugging time and affects production efficiency. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention proposes a sampling calibration device and calibration method. By employing a multi-level calibration method, the sampling calibration process is brought forward to the board testing stage, which improves the accuracy of the entire sampling calibration range and optimizes the equipment sampling calibration time in the project.

[0009] One of the technical solutions adopted in this invention is: a data acquisition and calibration device, comprising: an adjustable high-voltage power supply, a main circuit switch, a pre-charge switch, a pre-charge resistor, a supercapacitor, several parallel reference circuits, a subsequent circuit, a PCS sampling board, a PCS control motherboard, and a sampling and calibration controller; each reference circuit includes a controllable thyristor, a resistor, and a reference sensor connected in series; the subsequent circuit includes an inductor L1 and several series-connected sensors under test;

[0010] The positive terminal of the adjustable high-voltage power supply is connected to the first terminal of the main circuit switch, the second terminal of the main circuit switch is connected to the first terminal of the supercapacitor, and the second terminal of the supercapacitor is connected to the negative terminal of the adjustable high-voltage power supply; the first terminal of the precharge switch is connected to the first terminal of the main circuit switch, the second terminal of the precharge switch is connected to the first terminal of the precharge resistor, the second terminal of the precharge resistor is connected to the first terminal of the supercapacitor, the first terminal of each reference circuit is connected to the first terminal of the supercapacitor, the second terminal of each reference circuit is connected to the first terminal of the subsequent circuit, and the second terminal of the subsequent circuit is connected to the second terminal of the supercapacitor.

[0011] Each reference sensor is connected to the first terminal of the sampling calibration controller via the first sampling line; each sensor under test is connected to the first terminal of the PCS sampling board via the second sampling line; the second terminal of the PCS sampling board is connected to the first terminal of the PCS control motherboard; the second terminal of the PCS control motherboard is connected to the second terminal of the sampling calibration controller; and the third terminal of the sampling calibration controller is connected to the gate of each controllable thyristor.

[0012] The second technical solution adopted in this invention is: a current sensor sampling calibration method, comprising:

[0013] A1. Charge the supercapacitor using an adjustable high-voltage power supply. Once the supercapacitor is fully charged, disconnect the main circuit switch and the pre-charge switch.

[0014] A2. The sampling calibration controller performs a closing operation on one of the controllable thyristors each time, so that the corresponding reference circuit is connected to the subsequent circuit; each reference circuit is configured with a different measurement range;

[0015] A3. The calibration controller calibrates the sensor under test based on the data sampled by the sensor under test and the reference sensor.

[0016] A4. The calibration controller sends the calibrated current value of the sensor under test to the PCS control motherboard to update the sampling value of the sensor under test.

[0017] The beneficial effects of this invention are as follows: This invention constructs multiple reference circuits, each configured with resistors of different resistance values ​​to achieve testing at various current levels; by comparing the sampling curves of the reference sensor and the sensor under test, the result of whether software calibration is required is obtained; when software calibration is required, the sampling value of the sensor under test is calibrated by combining the zero-point offset of the sensor under test and the reference sensor, as well as the gain calibration coefficient; this invention achieves multi-level calibration, improving the accuracy of sampling calibration across the entire range. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the sampling device of the present invention;

[0019] Figure 2 This is a schematic diagram of the sampling circuit of the present invention;

[0020] Figure 3 This is a schematic diagram of the sampling and calibration fixture of the present invention;

[0021] Figure 4 This is a comparison chart of the sampling curves of the reference sensor and the sensor under test in this invention;

[0022] Figure 5 This is a comparison chart of the sampling curves of the reference sensor and the sensor under test after multiple sampling calibrations according to the present invention. Detailed Implementation

[0023] To facilitate understanding of the technical content of this invention by those skilled in the art, the following description, in conjunction with the accompanying drawings, further illustrates the invention.

[0024] In the field of power electronic equipment, excessive sampling errors can lead to a series of serious consequences. These include inaccurate power control in control systems, reduced system conversion efficiency, and damage to protective devices due to malfunctions. However, due to the limitations of sensor sampling accuracy, particularly its high nonlinearity, the same sampling parameters are difficult to adapt to all operating conditions of the equipment, posing control risks and significantly impacting project delivery time. This invention constructs a board-level testing fixture and method prior to overall system testing. It specifically addresses the nonlinear characteristics of sensors, improving the overall sampling accuracy across all operating conditions. Furthermore, it moves sampling calibration forward to the factory testing phase, completing all sampling calibrations at the board level and shortening project delivery time.

[0025] Given the importance of sampling calibration for power electronic equipment, this invention employs a multi-level calibration method, advancing the sampling calibration process to the board testing stage. This improves the accuracy of sampling calibration across the entire range and optimizes the equipment sampling calibration time in the project.

[0026] Due to the nonlinear characteristics of the sensor, conventional calibration methods have the greatest error when approaching zero and full scale. The multi-level calibration method adopted in this invention allows for the setting of denser segment points in areas where conventional methods have large errors, enabling local fine correction and reducing the error from 2% to less than 0.5%.

[0027] like Figure 1 As shown, the acquisition and calibration device of the present invention includes: an adjustable high-voltage power supply, a main circuit switch, a pre-charge switch, a pre-charge resistor, a supercapacitor, several parallel reference circuits, a subsequent circuit, a PCS sampling board, a PCS control motherboard, and a sampling and calibration controller; each reference circuit includes a controllable thyristor, a resistor, and a reference sensor connected in series; the subsequent circuit includes an inductor L1 and several sensors under test connected in series.

[0028] The positive terminal of the adjustable high-voltage power supply is connected to the first terminal of the main circuit switch, the second terminal of the main circuit switch is connected to the first terminal of the supercapacitor, and the second terminal of the supercapacitor is connected to the negative terminal of the adjustable high-voltage power supply; the first terminal of the precharge switch is connected to the first terminal of the main circuit switch, the second terminal of the precharge switch is connected to the first terminal of the precharge resistor, the second terminal of the precharge resistor is connected to the first terminal of the supercapacitor, the first terminal of each reference circuit is connected to the first terminal of the supercapacitor, the second terminal of each reference circuit is connected to the first terminal of the subsequent circuit, and the second terminal of the subsequent circuit is connected to the second terminal of the supercapacitor.

[0029] Each reference sensor is connected to the first terminal of the sampling calibration controller via the first sampling line; each sensor under test is connected to the first terminal of the PCS sampling board via the second sampling line; the second terminal of the PCS sampling board is connected to the first terminal of the PCS control motherboard; the second terminal of the PCS control motherboard is connected to the second terminal of the sampling calibration controller; and the third terminal of the sampling calibration controller is connected to the gate of each controllable thyristor.

[0030] like Figure 1 The anode of the controllable thyristor shown is connected to the positive terminal of the supercapacitor, and the cathode of the thyristor is connected to the resistor.

[0031] It also includes a voltage acquisition sensor connected to both ends of the supercapacitor, which is also connected to the PCS sampling board via a cable. The PCS sampling board transmits the acquired supercapacitor voltage to the sampling calibration controller via the PCS control motherboard. When the sampling calibration controller detects that the supercapacitor voltage reaches 0.9 times the adjustable power supply output voltage, it controls the main circuit switch to close.

[0032] The calibration process for the current sensor provided by this invention is as follows:

[0033] A1. Charge the supercapacitor using an adjustable high-voltage power supply;

[0034] A2. The sampling calibration controller closes one of the controllable thyristors each time, making the corresponding reference circuit and the subsequent circuit conduct; each reference circuit is equipped with a resistor of different resistance value;

[0035] A3. The calibration controller calibrates the sensor under test based on the data sampled by the sensor under test and the reference sensor.

[0036] A4. The calibration controller sends the calibrated current value of the sensor under test to the PCS control motherboard to update the sampling value of the sensor under test.

[0037] The implementation process of step A1 is as follows:

[0038] A11. The adjustable high-voltage power supply voltage range should be selected based on the rated DC voltage of the power electronic equipment under test, and the full voltage range should cover the sensor under test.

[0039] A12. The capacitor is pre-charged by the pre-charging resistor. When the detected voltage reaches 0.9 times the output voltage of the adjustable power supply, the main circuit switch is closed to charge the capacitor to full voltage.

[0040] Step A2 is as follows:

[0041] By using switching transistors Q1-Qn, only one switching transistor is closed at a time, making a single circuit conduct, and the switching transistors are controllable, enabling single-pulse conduction;

[0042] By using resistors R1-Rn with different resistance values, various current values ​​can be achieved in the circuit. Under the same power and voltage, the smaller the resistance value, the larger the current, and the larger the resistance value, the smaller the current, thus achieving different current levels.

[0043] In this embodiment, the reference sensors 1-n are selected from known sensors with the highest accuracy at each current level, and the current values ​​measured by the known sensors are used as reference currents for calibration and comparison of the sensors under test. The value of n is generally 3-5 segments. Assuming the range of the sensor under test is 0-1000A, it can be divided into five segments: 200A, 400A, 600A, 800A, and 1000A for calibration. If calibration in three segments does not meet the accuracy requirements, it is divided into four or five segments until the accuracy meets the standard. Generally, the larger the range of the sensor under test, the more pronounced the nonlinearity across the entire range may be, requiring more segments.

[0044] In this embodiment, one to n sensors under test are connected in series on a single circuit and calibrated simultaneously, thereby improving efficiency.

[0045] Step A3 is as follows:

[0046] A31. The sensor under test and the reference sensor provide the sampled data to the calibration controller (contrl) through different paths, and the sampled data is compared and calibrated in the controller.

[0047] like Figure 2 As shown, the reference sensor directly transmits the sampled reference current value to the sampling calibration fixture controller through the sampling line, and the conversion from analog to digital quantity is completed in the sampling calibration fixture controller.

[0048] The sampling data acquisition of the sensor under test is connected according to the actual power electronic equipment sampling circuit. Taking the sampling circuit of the energy storage converter as an example, the sampling signal of the sensor under test is first transmitted to the PCS sampling board. In the PCS board, the real signal is converted into a small signal, and then the sampling information is transmitted to the AD chip on the PCS control motherboard to complete the analog-to-digital conversion, so that the PCS main controller can complete real-time sampling. For example, the current sensor may transmit a 5V signal, which needs to be converted into a 3.3V signal required by the AD chip on the main control board; the same applies to voltage, directly sampling 400V and converting it into a 3.3V signal; that is, the signal transmitted to the AD chip on the PCS control motherboard during the current calibration process is a voltage signal. The control chip, such as the DSP, performs proportional calculations on the data transmitted from the AD chip to obtain the sampling data, and transmits this data to the calibration fixture controller through the communication protocol, where data comparison is performed during this period.

[0049] The PCS controller communicates with the sampling and calibration fixture controller via the external interface on the mainboard, transmitting the data samples from the PCS to the sampling and calibration controller, where sampling comparison and calibration are performed.

[0050] A32. The initial sampled values ​​of both the reference sensor and the sensor under test are transmitted to the sampling calibration fixture controller. The sampling calibration fixture controller compares and calibrates the sampled data of the sensor under test through the following calibration process, including the following steps:

[0051] A321. The reference sensor samples the data to the sampling calibration fixture controller. In the sampling calibration fixture controller, the fitted curve of the data collected during a single pulse closing is as follows: Figure 4 As shown, the horizontal axis represents time, and the vertical axis represents current value. All sampling data after the switch is closed is saved in the sampling calibration fixture controller for actual comparison and calibration. For ease of visualization by operators, as shown... Figure 3 As shown, the sampled data, along with the timestamp, is packaged and sent to the screen display via physical interfaces such as RS485 / Ethernet and communication protocols such as Modbus / Ethernet. The screen display generates a visual smooth and continuous curve through coordinate mapping and drawing.

[0052] When the capacitor is fully charged, the voltage is U, the current I through resistor R1 is 0, and the sampling values ​​of both the reference sensor and the sensor under test are 0.

[0053] like Figure 1 As shown, the sampled data enters the sampling calibration controller in two paths: one is the device's own reference sampling circuit, and the other is the complete board-level sampling circuit for the power electronic equipment. The sampling calibration controller acts as the main processor, analyzing and comparing the sampled data, sending sampling parameters to the controller of the device under test, and controlling the opening and closing of the thyristors in the sampling calibration device. The final output is a complete sampling circuit of the device under test with full sampling calibration.

[0054] like Figure 1 As shown, the sampling calibration fixture controller sends a closing signal to the first switching transistor, causing thyristor Q1 to close. At this time, the main circuit switch connected to the power supply is off, and the voltage source of the sampling circuit is the charge in the capacitor. At the instant of closing, the voltage across the capacitor is... The transient voltage across resistor R1 is 0, and the maximum current in the circuit at this time is... When the current reaches its peak, the charge loss within the capacitor will cause the voltage at the peak to be slightly lower than the peak voltage. At this point, voltage loss is negligible.

[0055] By controlling a reasonable voltage With resistance The value of makes the maximum current value when the circuit is turned on each time. Within the sampling range of the reference sensor in this loop, the reliability of the reference sensor sampling data is ensured.

[0056] A322. The sampling data from the sensor under test is not simply the acquisition of sensor data, but rather an integration of the entire sampling process of the power electronic equipment. The fitting curve of the sampling data is as follows: Figure 4 As shown.

[0057] The sampling process of the energy storage converter is as follows: the PCS sampling board collects all the data from the sensors under test, performs corresponding signal conversion processing, and transmits the signal to the AD chip on the PCS control motherboard for analog-to-digital conversion. The PCS control motherboard software program reads the digital value from the AD chip to obtain the original PCS sampling data.

[0058] During the initial sampling process, the sampling software parameters in the PCS control motherboard should be set to their initial values ​​to complete the sampling data acquisition of the hardware loop. In subsequent calibrations, if the difference between the sampled data and the reference sensor sampling is within the hardware sampling loop error range, the software sampling parameters should be corrected and calibrated. If the difference exceeds the hardware error range, a hardware loop problem should be considered, and hardware sampling loop components such as sensors and analog sampling boards should be checked and replaced sequentially.

[0059] The software sampling parameter calibration process is as follows: after the first sampling, the original sampling current of the PCS is obtained. The sampling calibration current is calculated by the sampling calibration fixture controller using a subsequent segmented calibration method. ,Will The communication protocol is used to send the signal to the PCS control motherboard, causing the PCS control motherboard to correct the sampling current. .

[0060] A323. Compare and analyze the sampling data from the two channels in the sampling calibration controller.

[0061] The collected sampling data from the sensor under test and the sampling data from the reference sensor are placed on the same time axis, and the data of the two curves are compared and analyzed as follows. The curves of the reference sensor and the sensor under test should have the same trend. Since power electronic equipment itself will operate under various operating conditions, it is necessary to ensure that the sensor characteristics are consistent.

[0062] A3231. First, with the circuit not connected (i.e., none of the switching transistors Q1-Qn are closed), take readings from the reference sampling sensor and the sensor under test respectively, and average the data for at least 3 minutes to obtain the current zero point of the reference sampling sensor. Zero point of the sensor under test ;

[0063] A3232. By using the sampling calibration fixture controller and performing a closing operation, the reference sampling curve and the measured calibration sampling curve are obtained respectively. The curves of the reference sensor and the measured sensor are compared one by one, such as... Figure 4 As shown. The reference sensor and the sensor under test have the same trend. At this time, we need to consider whether the sampling of the sensor under test is qualified. Taking the energy storage converter as an example, the basic requirement in the industry is that the grid-connected current accuracy is ±1%. When the sampling of the sensor under test exceeds ±1% compared with the reference sensor, after ruling out hardware problems, we perform software sampling calibration, that is, execute steps A3233-A3235.

[0064] Since the sensor's sampling accuracy is only sufficient and the sampled data is truly valid when the current passing through the test circuit is within its own calibration range, the reference sensor's sampling data is segmented according to the sensor's own calibration value. For example, if the maximum current of the device under test is 1000A, it can be divided into 5 segments for calibration sampling, selecting the sensor's maximum calibration values ​​as 200A, 400A, 600A, 800A, and 1000A respectively. The root mean square of the curve within the current range is used as comparison data. The effective value RMS0 of the reference sensor sampling is calculated as follows:

[0065]

[0066] in, Indicates the number of sampling points. This represents the current value at the nth sampling point;

[0067] Similarly, the effective value of the sampled sensor under test is calculated. 1. This yields two sampled values;

[0068] A3233. Assume that the original sampled value obtained by the measured sensor circuit at this time is... First, calculate the zero-point offset:

[0069]

[0070] Gain calibration factor:

[0071]

[0072] in, This is the effective value of the sampled sensor currently being tested, calculated in the same way as RMS0.

[0073] When the thyristor is closed, the original sampling current of the sensor under test is obtained. Based on zero-point offset and gain calibration coefficient Perform calibration; complete calibration formula:

[0074]

[0075] Substituting the actual parameters, we obtain the final formula:

[0076]

[0077] in, The original sampling current of the sensor under test. Calibrate the current of the sensor under test;

[0078] A3234. After comparing and calculating the sampling error using the sampling calibration fixture controller, the calibration parameters are... The settings are sent to the PCS control motherboard to update the sampling parameters of the device under test.

[0079] A3235. After the initial sampling calibration, the same thyristor circuit is subjected to multiple closing steps. Each time, a new gain coefficient is obtained based on the previous one. Through multiple sampling calibration tests, errors are eliminated, and the calibration is refined.

[0080]

[0081] like Figure 5 As shown, after three sampling calibrations, the sampling curve of the sensor under test is basically consistent with the sampling curve of the reference sensor, and the sampling value of the sensor under test is within ±1% of the sampling value of the reference sensor. Therefore, this sampling segment is considered to meet its own requirements.

[0082] A324. Repeat the process in A323, but in order to perform closing, sampling, comparative analysis, and calibration work on Q2, Q3, and so on, individually. Since the resistance values ​​in the test circuit increase or decrease sequentially, closing each circuit will satisfy a current range. At the minimum resistance value, the maximum current should be equal to the maximum rated current of the power electronic equipment used in the tested sampling circuit.

[0083] If the maximum current that the power electronic equipment can withstand is Imax, then a corresponding resistor value is selected for each channel to meet the requirements of 0.2Imax, 0.4Imax, 0.6Imax, 0.8Imax, Imax, etc. The more resistor levels there are, the more accurate the overall sampling will be.

[0084] When the measurement phase is divided into n stages, i.e., there are n measurement loops, integrating the sampling and calibration parameters yields the following formula, which makes... It has sufficiently high accuracy throughout the entire calibration range of power electronic equipment.

[0085]

[0086] in, , … Let represent the gain calibration coefficients for each of the n current levels, and b represent the zero-point offset. Represents the original sampled value. Indicates the calibration sample value. These are the current ranges corresponding to each of the n current levels.

[0087] A4. The sampling parameters obtained from the above formula The settings are sent to the PCS control motherboard, and the calibration is completed once the current is sampled.

[0088] Those skilled in the art will recognize that the embodiments described herein are for the purpose of helping to understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of the claims of the invention.

Claims

1. A data acquisition and calibration device, characterized in that, include: The system includes an adjustable high-voltage power supply, a main circuit switch, a pre-charge switch, a pre-charge resistor, a supercapacitor, several parallel reference circuits, a downstream circuit, a PCS sampling board, a PCS control motherboard, and a sampling calibration controller. Each reference circuit includes a controllable thyristor, a resistor, and a reference sensor connected in series. The downstream circuit includes an inductor L1 and several sensors under test connected in series. The positive terminal of the adjustable high-voltage power supply is connected to the first terminal of the main circuit switch, the second terminal of the main circuit switch is connected to the first terminal of the supercapacitor, and the second terminal of the supercapacitor is connected to the negative terminal of the adjustable high-voltage power supply; the first terminal of the precharge switch is connected to the first terminal of the main circuit switch, the second terminal of the precharge switch is connected to the first terminal of the precharge resistor, the second terminal of the precharge resistor is connected to the first terminal of the supercapacitor, the first terminal of each reference circuit is connected to the first terminal of the supercapacitor, the second terminal of each reference circuit is connected to the first terminal of the subsequent circuit, and the second terminal of the subsequent circuit is connected to the second terminal of the supercapacitor. Each reference sensor is connected to the first terminal of the sampling calibration controller via the first sampling line; each sensor under test is connected to the first terminal of the PCS sampling board via the second sampling line; the second terminal of the PCS sampling board is connected to the first terminal of the PCS control motherboard; the second terminal of the PCS control motherboard is connected to the second terminal of the sampling calibration controller; and the third terminal of the sampling calibration controller is connected to the gate of each controllable thyristor.

2. The data acquisition and calibration device according to claim 1, characterized in that, Each reference circuit corresponds to a different measurement range, and the resistors and reference sensors in the reference circuit are configured based on the measurement range corresponding to that reference circuit.

3. A sampling and calibration method for a current sensor, characterized in that, Both the reference sensor and the sensor under test are current sensors. The calibration process includes: A1. Charge the supercapacitor using an adjustable high-voltage power supply. Once the supercapacitor is fully charged, disconnect the main circuit switch and the pre-charge switch. A2. The sampling calibration controller performs a closing operation on one of the controllable thyristors each time, so that the corresponding reference circuit is connected to the subsequent circuit; each reference circuit is configured with a different measurement range; A3. The calibration controller calibrates the sensor under test based on the data sampled by the sensor under test and the reference sensor. A4. The calibration controller sends the calibrated current value of the sensor under test to the PCS control motherboard to update the sampling value of the sensor under test.

4. The current sensor sampling calibration method according to claim 3, characterized in that, The implementation process of step A1 is as follows: A11. The adjustable high-voltage power supply precharges the supercapacitor via a pre-charging resistor; A12. Once the supercapacitor voltage is detected to reach 0.9 times the adjustable power supply output voltage, the main circuit switch is closed to charge the supercapacitor to full voltage.

5. The current sensor sampling calibration method according to claim 4, characterized in that, The implementation process of step A3 is as follows: A31. The reference sensor transmits the sampled reference current value to the sampling calibration fixture controller through the sampling line, and the conversion from analog to digital quantity is completed in the sampling calibration fixture controller. The sampling signal of the sensor under test is transmitted to the PCS sampling board. The PCS board converts the real signal into a small signal and then transmits the sampling information to the AD chip on the PCS control motherboard to complete the analog-to-digital conversion, enabling the PCS main controller to perform real-time sampling. A32. The PCS main controller transmits the sampled data from the sensor under test after analog-to-digital conversion to the sampling calibration fixture controller. The sampling calibration fixture controller compares and calibrates the sampled data from the sensor under test, which includes the following steps: A321. Obtain the reference sensor fitting curve based on the sampling data of all reference sensors after the same controllable thyristor is closed; A322. Obtain the fitting curve of the sensor under test based on the sampling data of all the sensors under test after the same controllable thyristor is turned on. A323. On the same time axis, compare and analyze the fitting curve of the reference sensor and the fitting curve of the sensor under test. After ruling out hardware problems, when the sampling of the sensor under test exceeds ±1% compared with the reference sensor, perform software calibration on the sensor under test.

6. The current sensor sampling calibration method according to claim 5, characterized in that, The software calibration process described in step A323 is as follows: B1. When the circuit is not connected, read values ​​from the reference sensor and the sensor under test respectively, and average the reading values ​​over a set time period to obtain the zero point of the reference sampling sensor. Zero point of the sampling calibration loop under test ;according to and Calculate the zero-point offset: ； B2. Calculate the effective value RMS0 of the reference sensor and the effective value of the sensor under test, respectively. 1; Based on RMS0 and 1. Calculate the gain calibration factor: ； B3. After the thyristor is switched on, the original sampling current of the sensor under test is obtained. ,according to and right Perform calibration to obtain the calibrated current of the sensor under test in the current measurement range: ； in, The original sampling current of the sensor under test. Calibrate the current of the sensor under test; B4. Calibration parameters The settings are sent to the PCS control motherboard to update the sampling parameters of the device under test.

7. The current sensor sampling calibration method according to claim 6, characterized in that, The process involves repeatedly disconnecting and then reconnecting the same thyristor. Before each reconnection, the gain calibration coefficient is calculated according to step B2. After the thyristor is reconnected, the original sampling current of the sensor under test is acquired. ,according to Compare with all calculated gain calibration coefficients Perform calibration to obtain the calibrated current of the sensor under test in the current measurement range: ； in, The gain calibration coefficient is calculated based on step B2 before the first closing of the circuit. The gain calibration coefficient calculated based on step B2 before the second closing; This is the gain calibration coefficient calculated according to step B2 before a certain closing operation in the middle; This is the gain calibration coefficient calculated according to step B2 before the nth closing.

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