Remote calibration method for alternating-current voltage source based on Beidou common-view method

Abstract

The invention discloses an AC voltage source remote calibration method based on a Beidou common-view method, and the method comprises the following steps: S1, respectively installing Beidou satellite receivers on standard equipment and calibrated side equipment, and enabling the standard equipment and the calibrated side equipment to receive second pulse signals of the same Beidou satellite; s2, alternating-current voltage signals output by the standard equipment and the calibrated side equipment are collected, and an alternating-current voltage frequency conversion module calculates an ideal frequency value according to the collected alternating-current voltage signals and outputs a pulse signal with the corresponding frequency based on the ideal frequency value; s3, measuring the time deviation between the pulse signal and the second pulse output by the Beidou satellite synchronous clock source; s4, actual output frequencies of the calibrated side device and the standard device are calculated based on the time deviation, and a relative frequency deviation is calculated according to the actual output frequencies; and S5, calculating a voltage difference between the calibrated side equipment and the standard equipment based on the relative frequency deviation, and adjusting the calibrated side equipment based on the voltage difference.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and in particular to a remote calibration method for an alternating current voltage source based on a Beidou common-view method. Background Art

[0002] The application of metrology technology has promoted the development of instruments and meters in science and technology and social economy, and its role in daily production and life has become increasingly prominent. Now the detection and calibration of power equipment is directly related to the accuracy and reliability of measurement in all links of power production, and indirectly affects the safe and stable operation of new power systems. The value transfer and traceability of measuring instruments and control equipment are achieved through metrological verification and calibration. From a technical point of view, verification and calibration are mostly achieved by comparison method. At present, laboratory measurement is carried out by traditional manual methods, and most of the methods need to be offline. At the same time, the measuring instruments need to be dismantled and sent to the metrology laboratory for verification or calibration, and static or steady-state test process is carried out under the prescribed experimental environment.

[0003] AC voltage is one of the important parameters in the power system, providing a traceability basis for electromagnetic measurement and other measurement fields. Due to its high accuracy and wide measurement range, AC standard voltage source is usually used as a standard device for preserving and reproducing AC voltage values ​​and is widely used in various measurement institutions. Traditional manual calibration is inefficient, requires many precautions and has a cumbersome operation process. The technical level and work experience of the calibrator have a great impact on the measurement results. Therefore, it is necessary to introduce an effective remote calibration procedure to ensure the quality of measurement transmission and improve the efficiency of value transmission. In particular, with the extensive use of intelligent electrical measuring equipment in new power systems, timely and effective identification of the measurement performance of each intelligent electrical measuring equipment and ensuring the accuracy and reliability of measurement data can provide important guarantees for the stable operation of new power systems.

[0004] There are three main ways to achieve remote value transfer and traceability: one is to use the method of transferring standard tables / sources for on-site calibration; the second is to place the standard tables / sources on-site; the third is to use the measurement standard to remotely calibrate the on-site instruments in the laboratory through the Internet. The third value transfer method is currently limited to the field of time and frequency. The AC voltage remote calibration method based on the Beidou satellite common view method is to convert the voltage signal into a pulse signal, and then compare it with the satellite time and frequency signal, and finally use the third value transfer method to achieve remote calibration of the AC voltage. At present, the conversion accuracy of the general voltage-frequency conversion module is low, usually less than 0.2%, which cannot meet the use requirements of the remote calibration system of the satellite common view method. For some DC voltage-frequency conversion modules, the DC voltage conversion frequency accuracy technical index is 0.02%, which can only achieve DC voltage-frequency conversion below 20V, which cannot meet the use requirements of power production, and there are many conversion links, which introduces more uncertainty components, which ultimately leads to the relative expanded uncertainty of the AC voltage remote calibration system based on the Beidou satellite common view method greater than 0.2%, which greatly limits the application scenarios of the AC voltage remote calibration system based on the Beidou satellite common view method.

[0005] Traditional voltage-frequency conversion is usually implemented based on hardware circuits, which has problems such as high cost, poor flexibility, and limited accuracy. With the development of software technology, signal conversion through software algorithms has higher flexibility and scalability, but the existing software algorithms are for signals with sampling points evenly distributed in the entire cycle. Considering the real-time output of the effective value of the sampled signal pulse signal, synchronous sampling is not advisable in the past, so fixed-frequency sampling is required. However, fixed-frequency sampling has the periodic integrity of the sampling data. At present, most sampling linear interpolation effective value algorithms and spline interpolation effective value algorithms have large errors when non-sinusoidal signals are used, and cannot meet the accuracy requirements of AC signal effective value to frequency conversion. At the same time, there is edge extreme value distortion, which affects the accuracy of the measured effective value. Summary of the invention

[0006] In view of the above-mentioned prior art, the present invention provides an AC voltage source remote calibration method based on the Beidou common-view method, which mainly solves the technical problems existing in the above-mentioned background technology.

[0007] To achieve the above object, the technical solution of the embodiment of the present invention is implemented as follows:

[0008] A method for remote calibration of an AC voltage source based on Beidou common-view method, the method comprising the following steps:

[0009] S1. Install BeiDou satellite receivers on the standard device and the device to be calibrated respectively, so that the standard device and the device to be calibrated receive the same BeiDou satellite pulse signal;

[0010] S2, collecting the AC voltage signals output by the standard device and the device to be calibrated, the AC voltage frequency conversion module calculates the ideal frequency value according to the collected AC voltage signal, and outputs a pulse signal of the corresponding frequency based on the ideal frequency value;

[0011] S3, based on the output pulse signal, measuring the time deviation between the pulse signal and the second pulse output by the Beidou satellite synchronization clock source;

[0012] S4, calculating the actual output frequencies of the calibrated device and the standard device based on the time deviation, and obtaining a relative frequency deviation according to the actual output frequencies;

[0013] S5. Calculate the voltage difference between the device to be calibrated and the standard device based on the relative frequency deviation, and adjust the device to be calibrated based on the voltage difference.

[0014] Optionally, the AC voltage frequency conversion module calculates the ideal frequency value according to the collected AC voltage signal, and outputs a pulse signal of a corresponding frequency based on the ideal frequency value. Specifically, the AC voltage frequency conversion module interpolates the collected AC voltage signal by a three-interval combined interpolation method, calculates the ideal frequency value based on the AC voltage signal after the interpolation processing, and outputs a pulse signal of a corresponding frequency based on the ideal frequency value;

[0015] Optionally, the collected AC voltage signal is interpolated by a three-interval combined interpolation method, specifically including:

[0016] Dividing the AC voltage signal into three intervals, wherein the first interval is a linear area near the zero-crossing point, the second interval is a nonlinear area, and the third interval is a parabolic area near the peak point;

[0017] For the first interval, linear interpolation is used to achieve interpolation;

[0018] For the second interval, the Lagrange interpolation polynomial method is used for interpolation;

[0019] For the third interval, parabolic interpolation is used.

[0020] Optionally, calculating the ideal frequency value based on the interpolated AC voltage signal specifically includes: calculating the voltage effective value of the interpolated AC voltage signal, and obtaining the ideal frequency value by multiplying the voltage effective value by a voltage-frequency conversion coefficient.

[0021] Optionally, a first time deviation between the pulse signal output by the standard device and the second pulse output by the Beidou satellite synchronization clock source is measured by a time interval counter, and a second time deviation between the pulse signal output by the calibrated device and the second pulse output by the Beidou satellite synchronization clock source is measured.

[0022] Optionally, the actual output frequencies of the calibrated device and the standard device are calculated respectively based on the time deviation, and a relative frequency deviation is calculated based on the actual output frequencies, specifically including: calculating the actual output frequency of the pulse signal converted by the standard device based on the first time deviation, calculating the actual output frequency of the pulse signal converted by the calibrated device based on the second time deviation, subtracting the actual output frequency of the calibrated device from the actual output frequency of the standard device to obtain the relative frequency deviation between the calibrated device and the standard device.

[0023] Optionally, calculating the voltage difference between the calibrated device and the standard device based on the relative frequency deviation specifically includes: dividing the relative frequency deviation by a voltage-frequency conversion coefficient to obtain the voltage difference.

[0024] Optionally, the AC voltage frequency conversion module includes a reference circuit, a sampling circuit, an ADC converter, and an MCU core, wherein the output ends of the reference circuit and the sampling circuit are connected to the ADC converter signal, the input end of the sampling circuit is connected to the standard device / calibrated device, the output end of the ADC converter is connected to the MCU core signal, and the MCU core is used to perform triple interpolation processing on the AC voltage signals output by the standard device and the calibrated device, calculate the ideal frequency value corresponding to the AC voltage signal, and output a pulse signal based on the ideal frequency value.

[0025] The beneficial effects of the present invention are as follows: the method for remote measurement and calibration of AC voltage based on the Beidou satellite common-view method proposed in the present invention synchronizes the clock information on the Beidou satellite through a standard source and a satellite synchronization clock source on the calibrated side, and outputs two pulse signals with consistent standards. The higher the coincidence degree of the two signals, the higher the accuracy of the measurement and calibration system. The voltage signal conversion on the calibrated side is completed by designing a high-precision AC voltage frequency conversion module, and a continuous square wave pulse signal is output. The AC voltage frequency conversion module converts the AC voltage signals output by the standard and calibrated voltage sources into pulse signals of corresponding frequencies. The time interval counter measures the time deviation between this pulse and the second pulse output by the Beidou satellite synchronization clock source, and obtains the actual output frequency based on the time deviation, and finally obtains the relative frequency deviation based on the actual output frequency, calculates the voltage difference between the calibrated side device and the standard device based on the relative frequency deviation, and adjusts the calibrated side device based on the voltage difference, so as to realize remote measurement and calibration of multiple calibrated instruments and meters with the same time reference signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flowchart of a method for remote calibration of an AC voltage source based on the Beidou common-view method in an embodiment of the present application;

[0027] Figure 2This is a schematic diagram of the Beidou common-view method in the embodiment of this application;

[0028] Figure 3 This is a schematic diagram of the AC voltage signal partitioning intervals in the embodiment of the present application;

[0029] Figure 4 Schematic diagram of an AC voltage-frequency conversion module in an embodiment of the present application;

[0030] Figure 5 Schematic diagram of the PWM control circuit of the AC voltage-frequency conversion module in the embodiment of the present application. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further elaborated in detail below in conjunction with the drawings and specific embodiments of the specification. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the following description, the expression "some embodiments" is related to a subset of all possible embodiments, but it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0032] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0033] It should be understood that the present invention can be implemented in different forms and should not be interpreted as being limited to the embodiments proposed herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and the scope of the present invention will be fully conveyed to those skilled in the art. And the purpose of the terms used herein is only to describe specific embodiments and is not intended to be a limitation of the present invention. When used herein, the singular forms of "one", "one" and "said / the" are also intended to include plural forms, unless the context clearly indicates another way. It should also be understood that the terms "compose" and / or "include" when used in this specification determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0034] It should also be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "inside", "outside", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0035] In order to fully understand the present invention, a detailed structure will be proposed in the following description to illustrate the technical solution proposed by the present invention. The optional embodiments of the present invention are described in detail as follows, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0036] Please refer to the attached Figure 1 to Figure 2 The present application provides a method for remote calibration of an AC voltage source based on the Beidou common-view method, the method comprising the following steps:

[0037] S1. Install Beidou satellite receivers on the standard device and the device to be calibrated respectively, so that the standard device and the device to be calibrated receive the same Beidou satellite pulse signal, wherein the standard device is, for example, a standard voltage source, and the device to be calibrated is, for example, an AC voltage source;

[0038] S2, high-precision data acquisition equipment, collects the output AC voltage signals of the standard equipment and the equipment to be calibrated, collects the input AC voltage signals in real time through fixed-frequency oversampling technology, and converts them into digital signals. The collected digital signals are filtered, and advanced filtering algorithms including Hanning window, Hamming window or Blackman window (such as Hanning window, Hamming window or Blackman window, etc.) are used to eliminate noise and interference, and a reasonable zero-crossing detection threshold is set. Zero-crossing detection is performed on the filtered digital signal, and the time interval between two adjacent zero-crossing points is recorded, and the period of the AC voltage signal is accurately calculated based on this. The AC voltage frequency conversion module calculates the ideal frequency value according to the collected AC voltage signal, and outputs a pulse signal of the corresponding frequency based on the ideal frequency value;

[0039] S3, based on the output pulse signal, measuring the time deviation between the pulse signal and the second pulse output by the Beidou satellite synchronization clock source;

[0040] S4, calculating the actual output frequencies of the calibrated device and the standard device based on the time deviation, and obtaining a relative frequency deviation according to the actual output frequencies;

[0041] S5. Calculate the voltage difference between the device to be calibrated and the standard device based on the relative frequency deviation, and adjust the device to be calibrated based on the voltage difference.

[0042] The method for remote measurement and calibration of AC voltage based on the Beidou satellite common-view method proposed in the present invention synchronizes the clock information on the Beidou satellite through a standard source and a satellite synchronization clock source to be calibrated, and outputs two pulse signals with the same standard. The higher the coincidence degree of the two signals, the higher the accuracy of the measurement and calibration system. The voltage signal conversion of the calibrated side is completed by designing a high-precision AC voltage frequency conversion module, and a continuous square wave pulse signal is output. The AC voltage frequency conversion module converts the AC voltage signals output by the standard and calibrated voltage sources into pulse signals of corresponding frequencies. The time interval counter measures the time deviation between this pulse and the second pulse output by the Beidou satellite synchronization clock source, and obtains the actual output frequency based on the time deviation, and finally obtains the relative frequency deviation based on the actual output frequency, calculates the voltage difference between the calibrated side device and the standard device based on the relative frequency deviation, and adjusts the calibrated side device based on the voltage difference.

[0043] Furthermore, the voltage-frequency conversion module converts the input AC voltage value of 10V-1kV, 45Hz~65Hz into a pulse signal. The frequency of the pulse signal is linearly related to the numerical value of the AC voltage. The output range is: 10Hz~1MHz, the voltage-frequency conversion accuracy is better than 0.02%, and the annual stability is better than 0.03%. After the module converts the AC voltage signal into a pulse signal, the chip in the module design can significantly enhance the signal's anti-interference ability, and is also conducive to the high-precision long-distance transmission of the voltage-frequency conversion module based on the Beidou satellite common-view method.

[0044] In an optional implementation, the AC voltage frequency conversion module calculates an ideal frequency value according to the collected AC voltage signal, and outputs a pulse signal of a corresponding frequency based on the ideal frequency value. Specifically, the AC voltage frequency conversion module interpolates the collected AC voltage signal by a three-interval combined interpolation method, calculates an ideal frequency value based on the AC voltage signal after the interpolation processing, and outputs a pulse signal of a corresponding frequency based on the ideal frequency value;

[0045] like Figure 3 As shown, further, the collected AC voltage signal is interpolated by a three-interval combined interpolation method, specifically including:

[0046] Dividing the AC voltage signal into three intervals, wherein the first interval is a linear area near the zero-crossing point, the second interval is a nonlinear area, and the third interval is a parabolic area near the peak point;

[0047] For the first interval, the two intervals [h, a] and [d, e] are near the zero crossing point, which is close to the linear characteristic, and the linear interpolation method is used to realize the interpolation; for the given two sampling points (x0, y0) and (x1, y1), the corresponding voltage value y of any point x in the interval [x1, x2] can be obtained through interpolation processing. The continuous and accurate voltage signal curve of the first interval can be obtained, where the expression of y is:

[0048]

[0049] For the second interval, [a,b], [c,d], [e,f], [g,h], these intervals are in the nonlinear region, and polynomial interpolation is achieved, specifically using Lagrange interpolation polynomials. For the given n data points (x0,y0), (x1,y1), ..., (x n ,y n ), construct the Lagrange interpolation polynomial Through interpolation processing, a continuous and accurate voltage signal curve in the second interval can be obtained, where:

[0050]

[0051] For the third interval, [b, c] and [f, g] are at the peak points of the AC signal, which is approximate to a parabola. The parabola interpolation method is used to implement interpolation. The specific formula is: y=ax^2+bx+c, where the coefficients a, b, and c are obtained by substituting the coordinates of the three sampling points to solve the equation group. For the three sampling points (x1, y1), (x2, y2), and (x3, y3), the parabola interpolation function in the interval (x1, y3) is y=ax^2+bx+c. 2 +bx+c, where coefficients a, b, and c are obtained by substituting the coordinates of the three sampling points into the interpolation function and solving the equations. Through interpolation processing, a continuous and accurate voltage signal curve for interval 3 can be obtained.

[0052] Compared with traditional hardware conversion methods, the three-interval combined interpolation method can perform high-precision interpolation between given data points, thereby more accurately restoring the true form of the AC voltage signal and improving the accuracy of effective value calculation. Through efficient interpolation algorithms and optimized calculation processes, the AC voltage signal can be quickly processed to achieve real-time output frequency values ​​and meet the requirements for system response speed. The algorithm is suitable for various types of AC voltage signals, including sinusoidal waves, non-sinusoidal waves, and signals containing noise and interference, and has strong adaptability. The implementation process of the algorithm is relatively simple, does not require complex hardware equipment and expensive sensors, and can be easily integrated and applied in existing power electronic systems.

[0053] Furthermore, the ideal frequency value is calculated based on the AC voltage signal after interpolation processing, specifically including: calculating the voltage effective value of the AC voltage signal after interpolation processing, and obtaining the ideal frequency value after multiplying the voltage effective value by the voltage-frequency conversion coefficient. Compared with the traditional hardware conversion method, it has the advantages of low cost, high flexibility, easy maintenance and upgrade, etc. Through fixed-frequency oversampling, filtering the digital signal, zero-crossing detection signal period, calculating the AC voltage effective value after performing cubic spline interpolation through the signal period, and adjusting the output signal frequency through the effective value control frequency word, etc., the accuracy and stability of the conversion are effectively improved, which can meet various application scenarios that require the conversion of AC voltage signals into pulse signals.

[0054] By using this method, the frequency range of the input AC voltage signal can be set to 50Hz-60Hz, and the sampling frequency can be set to 1kHz. After the AC voltage signal is collected by the sensor and converted into a digital signal, the time interval between adjacent zero crossing points can be accurately detected in the zero crossing detection. After frequency calculation and median filtering (selecting 5 adjacent frequency values ​​for median filtering), a stable and accurate frequency output signal is obtained by the three-interval combination algorithm. For AC voltage signals with an input frequency range of 20Hz-100Hz, the sampling frequency is increased to 2kHz. In addition, only appropriate parameter adjustments are needed for the zero crossing detection and filtering processing to adapt to different input signal characteristics.

[0055] In an optional embodiment, a first time deviation between the pulse signal output by the standard device and the second pulse output by the Beidou satellite synchronization clock source is measured by a time interval counter, and a second time deviation between the pulse signal output by the calibrated device and the second pulse output by the Beidou satellite synchronization clock source is measured.

[0056] Specifically, during the observation period, the Beidou satellite receiver at the standard device / the device being calibrated records the pseudorange (Pseudorange), carrier phase (Carrier Phase) and other data of the satellite at the standard device / the device being calibrated. For each observation moment, the pseudorange difference of the same satellite received by the standard end and the calibrated source side is calculated. Since the standard end and the calibrated source side observe the same satellite at the same time, the common errors they are subject to (such as satellite clock error, ionospheric delay, tropospheric delay, etc.) are the same. Therefore, the pseudorange difference mainly reflects the time deviation between the two stations. Dividing the pseudorange difference by the speed of light can obtain the time deviation between the calibrated device and the standard device.

[0057] Furthermore, the actual output frequencies of the calibrated device and the standard device are calculated respectively based on the time deviation, and the relative frequency deviation is calculated according to the actual output frequencies, specifically including: calculating the actual output frequency of the pulse signal converted by the standard device based on the first time deviation, calculating the actual output frequency of the pulse signal converted by the calibrated device based on the second time deviation, subtracting the actual output frequency of the calibrated device from the actual output frequency of the standard device to obtain the relative frequency deviation between the calibrated device and the standard device.

[0058] Specifically, the actual output frequency of a standard device is calculated as:

[0059]

[0060] The method for calculating the actual output frequency of the device being calibrated is:

[0061]

[0062] Where Δt A is the first time deviation, Δt B is the second time deviation, f0 A is the ideal output frequency of the standard device, f0 B is the ideal output frequency of the device being calibrated, and T is the sampling period.

[0063] Further, the voltage difference between the calibrated device and the standard device is calculated based on the relative frequency deviation, specifically including: dividing the relative frequency deviation by the voltage-frequency conversion coefficient to obtain the voltage difference. Specifically, the voltage difference is calculated as follows:

[0064]

[0065] Where λ is the voltage-to-frequency conversion coefficient.

[0066] See also Figure 4-Figure 5 In an optional embodiment, the AC voltage frequency conversion module includes a reference circuit, a sampling circuit, an ADC converter, and an MCU core, wherein the output ends of the reference circuit and the sampling circuit are connected to the ADC converter signal, the input end of the sampling circuit is connected to the standard device / calibrated device, the output end of the ADC converter is connected to the MCU core signal, and the MCU core is used to perform triple interpolation processing on the AC voltage signals output by the standard device and the calibrated device, calculate the ideal frequency value corresponding to the AC voltage signal, and output a pulse signal based on the ideal frequency value.

[0067] The voltage-frequency conversion module converts the analog voltage into a pulse signal. The frequency of the output pulse signal is proportional to the input voltage, indicating that the pulse signal information can reflect the voltage information. After the voltage signal is converted into a pulse signal, the anti-interference ability of the signal can be significantly enhanced, which is also conducive to long-distance transmission. The system provides a continuously adjustable high-precision test reference source voltage, and the voltage is sent to the integrated chip for V / F conversion after precise amplification and biasing.

[0068] Sampling circuit: Use high-precision, low-temperature floating voltage divider resistors to switch sampling according to the gear position.

[0069] Reference circuit: Using ADR1399, the ADR1399 precision shunt reference has excellent temperature stability over a wide range of voltage, temperature, and quiescent current. The ADR1399 combines a temperature stabilization loop and an active Zener on a monolithic substrate to virtually eliminate voltage variations with temperature. The ADR1399 precision shunt reference is designed for applications such as ultra-stable digital voltmeters, precision calibration equipment, and super repeatable analog-to-digital converters (ADCs).

[0070] ADC chip: 20-bit SAR high-speed ADC is used to achieve high-speed sampling output. The ADC chip is to be LTC2378-20, which is a low-noise, low-power, high-speed 20-bit successive approximation register (SAR) ADC. LTC2378-20 uses a single 2.5V power supply and supports a large and flexible ±VREF fully differential input range (VREF changes from 2.5V to 5.1V), making it very suitable for high-performance applications that require a wide dynamic range.

[0071] Power module: adopts extremely low noise LDO design, which can effectively reduce noise.

[0072] Frequency output interface: adopts full isolation scheme, which can effectively ground and prevent damage.

[0073] MCU core and algorithm: MUC core uses large-scale imported integrated circuits, high-speed digital processors (ARM), and complex programmable logic arrays (FPGA). It is planned to use XC7Z020 from Xilinx's ZYNQ series chips. The chip has a dual-core Cortex-A9 ARM, and runs at a speed of up to 800MHz, with a processing performance of up to 4000M mips. It also supports multiple operating systems such as UCOS, QNX, and Linux. The ARM part has common peripherals such as USB, Ethernet, CAN, UARR, and SPI. At the same time, the chip has a built-in FPGA with a capacity of 85K logic gates, which is suitable for system expansion and provides 200 general-purpose programmable IO pins. The algorithm uses a three-interval combined interpolation method to perform high-precision interpolation between given data points, thereby more accurately restoring the true form of the AC voltage signal and improving the accuracy of the effective value calculation. Through efficient interpolation algorithms and optimized calculation processes, the AC voltage signal can be quickly processed to achieve real-time output frequency values, meeting the requirements for system response speed.

[0074] The MCU core uses a three-interval combined interpolation method to perform high-precision interpolation between given data points, thereby more accurately restoring the true form of the AC voltage signal and improving the accuracy of effective value calculation. Through efficient interpolation algorithms and optimized calculation processes, the AC voltage signal can be quickly processed to achieve real-time output frequency values ​​and meet the requirements for system response speed. The algorithm is suitable for various types of AC voltage signals, including sine waves, non-sinusoidal waves, and signals containing noise and interference. It has strong adaptability and robustness. The implementation process of the algorithm is relatively simple and does not require complex hardware equipment and expensive sensors.

[0075] Furthermore, the voltage-frequency conversion module also includes an instrument amplifier, which is mainly used to amplify input signals in the case of two high-impedance inputs, because the signal source is usually a high-impedance output. If a classic differential amplifier is used, the input impedance of the amplifier will inevitably lower the input voltage. Therefore, this application specifically adopts an instrument amplifier.

[0076] Furthermore, the PWM output signal of the MCU core uses optocoupler isolation output. Generally, the voltage of the control circuit is low, but the external devices are often complex, with high voltage and large interference. Therefore, usually some isolation circuits are needed at both the input and output ends to prevent external spike pulse signals from destroying the control circuit, such as the optocoupler isolation circuit summarized in this article. The optocoupler isolation circuit mainly uses the combination of light-emitting diodes and phototransistors to achieve electrical signal isolation.

[0077] After the design of the AC voltage-frequency conversion module based on the Beidou satellite common-view method was completed, it was experimentally verified. The experimental data is shown in the following table:

[0078]

[0079]

[0080] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. The protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for remote calibration of an AC voltage source based on Beidou common-view method, characterized in that: The method comprises the following steps: S1. Install BeiDou satellite receivers on the standard device and the device to be calibrated respectively, so that the standard device and the device to be calibrated receive the same BeiDou satellite pulse signal; S2, collecting the AC voltage signals output by the standard device and the device to be calibrated, the AC voltage frequency conversion module calculates the ideal frequency value according to the collected AC voltage signal, and outputs a pulse signal of the corresponding frequency based on the ideal frequency value; S3, based on the output pulse signal, measuring the time deviation between the pulse signal and the second pulse output by the Beidou satellite synchronization clock source; S4, calculating the actual output frequencies of the calibrated device and the standard device based on the time deviation, and obtaining a relative frequency deviation according to the actual output frequencies; S5. Calculate the voltage difference between the device to be calibrated and the standard device based on the relative frequency deviation, and adjust the device to be calibrated based on the voltage difference.

2. The method for remote calibration of an AC voltage source based on Beidou common-view method according to claim 1, characterized in that: The AC voltage frequency conversion module calculates the ideal frequency value according to the collected AC voltage signal, and outputs a pulse signal of the corresponding frequency based on the ideal frequency value. Specifically, the AC voltage frequency conversion module interpolates the collected AC voltage signal through a three-interval combined interpolation method, calculates the ideal frequency value based on the AC voltage signal after the interpolation processing, and outputs a pulse signal of the corresponding frequency based on the ideal frequency value; 3. The method for remote calibration of an AC voltage source based on Beidou common-view method according to claim 2, characterized in that: The collected AC voltage signal is interpolated by a three-interval combined interpolation method, specifically including: Dividing the AC voltage signal into three intervals, wherein the first interval is a linear area near the zero-crossing point, the second interval is a nonlinear area, and the third interval is a parabolic area near the peak point; For the first interval, linear interpolation is used to achieve interpolation; For the second interval, the Lagrange interpolation polynomial method is used for interpolation; For the third interval, parabolic interpolation is used.

4. The method for remote calibration of an AC voltage source based on Beidou common-view method according to claim 3, characterized in that: Calculating the ideal frequency value based on the interpolated AC voltage signal specifically includes: calculating the voltage effective value of the interpolated AC voltage signal, and multiplying the voltage effective value by a voltage-frequency conversion coefficient to obtain the ideal frequency value.

5. The method for remote calibration of an AC voltage source based on Beidou common-view method according to claim 4, characterized in that: The first time deviation between the pulse signal output by the standard device and the second pulse output by the Beidou satellite synchronization clock source is measured by a time interval counter, and the second time deviation between the pulse signal output by the calibration device and the second pulse output by the Beidou satellite synchronization clock source is measured.

6. The method for remote calibration of an AC voltage source based on Beidou common-view method according to claim 5, characterized in that: Based on the time deviation, the actual output frequencies of the calibrated device and the standard device are calculated respectively, and the relative frequency deviation is calculated according to the actual output frequencies, specifically including: based on the first time deviation, calculating the actual output frequency of the pulse signal converted by the standard device, based on the second time deviation, calculating the actual output frequency of the pulse signal converted by the calibrated device, subtracting the actual output frequency of the calibrated device from the actual output frequency of the standard device, and obtaining the relative frequency deviation between the calibrated device and the standard device.

7. The method for remote calibration of an AC voltage source based on Beidou common-view method according to claim 6, characterized in that: Calculating the voltage difference between the calibrated device and the standard device based on the relative frequency deviation specifically includes: dividing the relative frequency deviation by a voltage-frequency conversion coefficient to obtain the voltage difference.

8. A method for remote calibration of an AC voltage source based on Beidou common-view method according to any one of claims 1 to 7, characterized in that: The AC voltage frequency conversion module includes a reference circuit, a sampling circuit, an ADC converter, and an MCU core, wherein the output ends of the reference circuit and the sampling circuit are connected to the ADC converter signal, the input end of the sampling circuit is connected to the standard device / calibrated device, the output end of the ADC converter is connected to the MCU core signal, and the MCU core is used to perform triple interpolation processing on the AC voltage signals output by the standard device and the calibrated device, calculate the ideal frequency value corresponding to the AC voltage signal, and output a pulse signal based on the ideal frequency value.

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