Intelligent electric meter based on remote calibration of beidou satellite signal

Abstract

This application provides a smart meter based on remote calibration using BeiDou satellite signals, relating to the field of power metering instrument technology. The smart meter includes a satellite common-view synchronization unit, a voltage sampling and calibration unit, a current sampling and calibration unit, a conversion unit, and a control and communication unit. The satellite common-view synchronization unit receives BeiDou satellite signals to provide a unified time reference. The conversion unit includes a reciprocal V / F converter and a reciprocal I / F converter, realizing bidirectional conversion between voltage / current signals and frequency signals. The microcontroller switches between self-calibration mode and metering mode in response to host computer commands. In self-calibration mode, the reciprocal converter performs frequency calibration and measures and corrects the actual voltage division ratio coefficient and current division ratio coefficient. In metering mode, the voltage and current signals are dynamically corrected based on the corrected coefficients, and the electrical energy is calculated. This application achieves remote, high-precision self-calibration of the meter, with high metering accuracy, supports visualized centralized management, and significantly reduces operation and maintenance costs.

Description

Technical Field

[0001] This application relates to the field of power metering technology, and in particular to a smart meter based on remote calibration using BeiDou satellite signals. Background Technology

[0002] In the existing technology, the calibration of electricity meter energy measurement is mainly divided into two major systems: traditional on-site calibration and emerging remote calibration. (i) Traditional on-site calibration mainly involves manual carrying of high-precision standard meters and portable calibrators to the location where the meters are installed to conduct real / virtual load calibration. This requires disconnecting the metering circuit wiring and relies on on-site operation by calibration personnel. Not only does this result in long calibration cycles and high labor costs due to the large number and wide distribution of meters, but it also has problems such as insufficient error assessment under dynamic load, electromagnetic interference affecting calibration accuracy, and cumbersome traceability of calibration results. Furthermore, it is difficult to achieve dynamic monitoring at all times and at high frequencies.

[0003] (ii) Although remote calibration related technologies have been gradually developed, such as embedding lightweight adapter testers and connecting energy comparators into the metering circuit of electricity meters, combining 4G / 5G, WiFi and other Internet of Things communication technologies, and using satellite time synchronization to achieve clock synchronization, relying on the cloud platform to perform remote data comparison and error calculation, the initial goal of simultaneous metering and testing and unattended operation has been achieved.

[0004] Although existing technologies offer both on-site and remote calibration methods, these solutions still have many shortcomings: (i) Insufficient adaptability of metering accuracy, lack of technical design for dynamic correction of sampling coefficients, and inability to correct metering results in real time under actual power consumption conditions, resulting in deviation between metered values ​​and true values, making it difficult to meet the requirements of high-precision metering. (ii) The calibration mechanism has obvious defects. It cannot complete its own remote self-calibration during the idle period of the electricity meter, it is difficult to ensure that the accuracy of the module is consistent with the laboratory standard, and it is impossible to accurately obtain the actual measurement error of the electricity meter. (iii) The traceability and integration of measurement values ​​are low. Satellite common-view technology is not used to achieve accurate traceability of voltage and current parameters to the laboratory. Furthermore, an integrated structure has not been formed. When applied, the metering circuit of the electricity meter needs to be significantly modified, which not only results in poor compatibility but also increases the deployment cost and difficulty. (iv) The laboratory-side equipment is cumbersome in design, and the standard voltage source and standard constant current source are not highly integrated. The equipment structure is complex and difficult to operate, which increases the application cost and management burden of the laboratory. Summary of the Invention

[0005] This application provides a smart meter based on remote calibration using BeiDou satellite signals to solve at least one of the following technical problems: (i) It can dynamically correct the sampling coefficient and correct the measurement results in real time, which greatly improves the measurement accuracy and makes the measurement results consistent with the true value; (ii) The meter can be calibrated periodically when it is working or can perform remote self-calibration when it is idle, ensuring that the meter's accuracy is always consistent with the laboratory standard. (iii) Satellite common-view technology is used to achieve accurate traceability of voltage and current values ​​to the laboratory. At the same time, the self-calibration function of the meter is highly integrated with devices such as voltage source, constant current source, and reciprocating voltage-frequency conversion module to form an integrated smart meter. (iv) A simple, highly integrated laboratory module was developed in parallel, which integrates a standard voltage source and a standard constant current source, greatly simplifying the operation and management of laboratory equipment; (v) The entire system is also equipped with a dedicated human-computer interaction interface, which can be used to visualize and centrally manage all remotely calibrated smart energy meters on the laboratory host computer, and obtain a series of key information such as the model, location, current operating status and working status of the remotely calibrated smart energy meters in real time.

[0006] To achieve the above objectives, this application adopts the following technical solution: This application provides a smart meter based on remote calibration using BeiDou satellite signals, comprising: The satellite common-view synchronization unit is used to receive BeiDou satellite signals and output standard second pulse signals to provide a unified time reference for electricity meters. The voltage sampling and calibration unit includes a voltage divider circuit, a first switching node, a second sampling node, a reference voltage source, and a first analog-to-digital converter. The input terminal of the voltage divider circuit is connected to a live wire, and its output terminal is connected to a metering path and a calibration path via the first switching node. The second sampling node is connected to the sampling terminal of the voltage divider circuit and is used to collect the actual voltage division ratio coefficient of the voltage divider circuit. The current sampling and calibration unit includes a shunt, a third switching node, a fourth switching node, a fifth sampling node, a reference constant current source, and a second analog-to-digital converter. The shunt is connected in series in the live wire loop, and its two ends are connected to the metering path or the calibration path via the third switching node and the fourth switching node, respectively. The fifth sampling node is connected to the voltage sampling terminal of the shunt and is used to collect the actual shunt ratio coefficient of the shunt. The conversion unit includes a reciprocating voltage-to-frequency converter and a reciprocating I / F converter; the reciprocating voltage-to-frequency converter is used to realize bidirectional conversion between voltage signals and frequency signals, and the reciprocating I / F converter is used to realize bidirectional conversion between current signals and frequency signals. The control and communication unit includes a microcontroller and a communication module; the microcontroller is electrically connected to the satellite common-view synchronization unit, the first switching node, the second sampling node, the third switching node, the fourth switching node, the fifth sampling node, the reference voltage source, the reference constant current source, the first analog-to-digital converter, the second analog-to-digital converter, the reciprocal voltage-to-frequency converter, and the reciprocal I / F converter, and is configured as follows: In response to a calibration command received from the host computer via the communication module, the system switches between self-calibration mode and metrology mode. When in self-calibration mode: First, the frequency of the reciprocal voltage-frequency converter and the reciprocal I / F converter is calibrated. Then, the actual voltage division ratio coefficient and the actual current division ratio coefficient are measured and corrected using the reciprocal voltage-frequency converter, the reciprocal I / F converter, the reference voltage source and the reference constant current source calibrated by the satellite common-view synchronization unit. When in metering mode: control the first, third, and fourth switching nodes to switch to the metering path, and dynamically correct the voltage and current signals collected by the first analog-to-digital converter and the second analog-to-digital converter based on the corrected actual voltage division ratio coefficient and the actual current division ratio coefficient, and calculate the electrical energy. The measurement data and calibration results are uploaded to the host computer through the communication module.

[0007] Preferably, in the above-mentioned smart meter based on remote calibration using BeiDou satellite signals, the microcontroller is further configured to perform frequency calibration on the reciprocating voltage-to-frequency converter in the following manner: The initial voltage is obtained using the second pulse signal output by the satellite common-view synchronization unit as the time reference. Measure the time interval between the rising edges of the second pulse and the converted square wave pulse. and the number of pulses in the i-th second ,according to Calculate the initial standard voltage frequency And calculate the initial voltage forward conversion coefficient. and initial voltage reverse conversion coefficient ; Get the current voltage frequency ,like If an anomaly is detected, switch to reverse mode and, based on the... Voltage discrimination frequency with equal values Generate discrimination voltage ,contrast and :like Then let the current voltage forward conversion coefficient be... Increase the current voltage reverse conversion factor If it becomes smaller Then let the current voltage forward conversion coefficient be... Decreasing, current voltage reverse conversion factor Get bigger; The current voltage forward conversion factor Positive conversion coefficient to the initial voltage of storage By approximating and correcting, the corrected voltage frequency is obtained. Calculate voltage frequency deviation ,like Then repeat the correction until... .

[0008] Preferably, in the above-mentioned smart meter based on remote calibration using BeiDou satellite signals, the microcontroller is further configured to perform frequency calibration on the reciprocal I / F converter in the following manner: The reference current is obtained by using the second pulse signal output by the satellite common-view synchronization unit as the time reference. Measure the time interval between the rising edges of the second pulse and the converted square wave pulse. and the number of pulses in the i-th second ,according to Calculate the initial standard current frequency, and then calculate the initial current forward conversion factor. and the reverse conversion coefficient of the initial current ; Get current frequency ,like If an anomaly is detected, switch to reverse mode and, based on the... Current discrimination frequency with equal values Generate discrimination current ,contrast and :like This will increase the forward conversion factor of the current current and decrease the reverse conversion factor of the current current. This will decrease the forward conversion factor of the current current and increase the reverse conversion factor of the current current; Convert the current forward conversion factor to the initial current forward conversion factor. By approximating and correcting, the corrected current frequency is obtained. Calculate the current frequency deviation ,like Then repeat the correction until... .

[0009] Preferably, in the above-mentioned smart meter based on remote calibration using BeiDou satellite signals, the microcontroller is further configured to measure and correct the actual voltage division ratio coefficient in the following manner: Control the output voltage of the reference voltage source The sampled voltage is obtained after voltage division in the voltage divider circuit. Control the second sampling node to turn on. and The channel sequentially feeds the two voltage signals into the reciprocating voltage-to-frequency converter, converting them into corresponding frequency signals. and The actual partial pressure ratio coefficient is calculated using the following formula. And store corrections:

[0010] Preferably, in the above-mentioned smart meter based on remote calibration using BeiDou satellite signals, the microcontroller is further configured to measure and correct the actual shunt ratio coefficient in the following manner: Control the output current of the reference constant current source The voltage drop generated by the shunt results in a corresponding sampling voltage across the shunt. and Control the fifth sampling node to turn on. and The channel is converted into a corresponding frequency signal by the reciprocal frequency converter. and The actual split ratio coefficient is calculated using the following formula. And store corrections:

[0011] Preferably, in the above-mentioned smart meter based on remote calibration using BeiDou satellite signals, the microcontroller is further configured to calibrate the reference voltage source and the reference constant current source in the following manner: The communication module receives calibration data from a standard voltage source in the laboratory. Using the BeiDou satellite synchronous clock signal as the time reference, the voltage deviation between the calibrated voltage source and the standard voltage source is calculated according to the remote metrology model. : in, , These are the voltage-frequency conversion coefficients for the laboratory standard terminal and the field calibration terminal, respectively. , These represent the sum of the maximum and minimum time intervals between the laboratory standard terminal and the field calibration terminal, respectively.

[0012] Preferably, in the above-mentioned smart meter based on remote calibration using BeiDou satellite signals, when the microcontroller is further configured to execute the metering mode, the total electrical energy is calculated using the following formula: in, This is the original voltage sample value. This is the original current sampling value. This is the actual partial pressure ratio coefficient. This is the actual split ratio coefficient. and These are the upper and lower limits of the integral, respectively. It is a time variable.

[0013] Preferably, in the smart meter based on remote calibration using BeiDou satellite signals, the microcontroller is further configured to: execute a self-calibration mode once every set time when the meter is in working condition; and continuously execute the self-calibration mode when the meter is in an unpaid idle state.

[0014] Preferably, in the smart meter based on remote calibration of Beidou satellite signals, when the microcontroller interacts with the remote host computer through the communication module, the data transmission adopts an encryption protocol; when the host computer exceeds a preset threshold, it automatically pops up an alarm and locates the meter position.

[0015] Preferably, in the smart meter based on remote calibration of BeiDou satellite signals, the voltage divider circuit includes a 200:1 voltage divider circuit composed of metal foil resistors; the shunt is a 0.05-class standard shunt; and both the first analog-to-digital converter and the second analog-to-digital converter are ADC chips.

[0016] The smart meter based on remote calibration using BeiDou satellite signals provided in this application has at least the following beneficial effects: 1. This application provides a unified time reference for electricity meters by receiving Beidou satellite signals and outputting standard second pulse signals. This allows the traceability of voltage and current parameters to rely on satellite clock signals as a non-physical standard transmission medium, eliminating the need for manual on-site operation with standard instruments. This eliminates additional errors such as transportation and electromagnetic interference in traditional calibration, ensuring the accuracy and reliability of traceability.

[0017] 2. This application sets up a self-calibration mode and a metering mode in the smart meter. The microcontroller can switch between the two modes in response to calibration commands from the host computer. In self-calibration mode, the frequency of the reciprocal V / F converter and the reciprocal I / F converter is first calibrated. Through iterative correction of the forward and reverse conversion coefficients, the frequency deviation is reduced to zero, achieving accurate bidirectional conversion between voltage and frequency signals, and between current and frequency signals. Based on this, the actual voltage division ratio coefficient and the actual current division ratio coefficient are measured and corrected using a reference voltage source and a reference constant current source calibrated by satellite common-view. The meter can perform self-calibration every 30 minutes during operation and continuously perform self-calibration during idle periods, thereby ensuring that the meter's accuracy is consistent with the laboratory standard in real time, solving the problems of insufficient dynamic load error assessment and long calibration cycles in traditional on-site calibration.

[0018] 3. This application dynamically measures and corrects the actual voltage division ratio of the voltage divider circuit and the actual current shunt ratio of the shunt, converting the two voltage or current signals into corresponding frequency signals. The actual sampling coefficient is calculated based on the frequency ratio and stored for correction. In metering mode, based on the corrected actual voltage division ratio and actual current shunt ratio, the voltage and current signals acquired by the analog-to-digital converter are dynamically corrected, and the total electrical energy is calculated by time integration using a trapezoidal integration algorithm with a sampling interval not exceeding fifteen seconds. This ensures that the uncertainties of the satellite common-view channel, voltage calibration channel, and current calibration channel are all controlled at extremely low levels, and the truncation error is effectively suppressed. The meter readings closely match the true values, meeting the requirements for high-precision power metering.

[0019] 4. This application highly integrates the satellite common-view synchronization unit, voltage sampling and calibration unit, current sampling and calibration unit, conversion unit including reciprocal V / F converter and reciprocal I / F converter, and control and communication unit into a single structure. This eliminates the need for significant hardware modifications to existing electricity metering circuits, resulting in strong adaptability. Simultaneously, the laboratory end highly integrates the standard voltage source and standard constant current source, simplifying the equipment structure and operating procedures.

[0020] 5. This application interacts with a remote host computer via a communication module. The microcontroller can upload metering data and calibration results to the host computer and receive calibration commands from the host computer. Data transmission uses an encrypted protocol. When the metering error exceeds a preset threshold, the host computer can automatically pop up an alarm and locate the meter. The laboratory host computer can centrally and visually manage all meters distributed in different areas, displaying key information such as meter model, installation location, operating status, working mode, calibration coefficient, and metering error in real time. It supports remote issuance of calibration commands and storage and retrieval of historical data, realizing large-scale and intelligent management of meter calibration and solving the problems of decentralized and inefficient management in existing technologies.

[0021] 6. This application requires no manual on-site operation throughout the entire process, saving the labor and time costs of traditional on-site calibration. The on-site end adopts an integrated structure, and the laboratory end equipment is highly integrated, reducing equipment procurement and management costs. The correction and update frequency of the actual voltage ratio coefficient and the actual current ratio coefficient reaches once every 100 milliseconds. The high-frequency real-time monitoring and automated calibration reduce metering disputes caused by metering errors, further reducing the hidden costs of power metering operation and maintenance. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] Figure 1A flowchart illustrating a smart meter based on remote calibration using BeiDou satellite signals, provided as an embodiment of this application; Figure 2 This application provides a structural diagram of a laboratory-side integrated standard module. Figure 3 This is a data processing flowchart of a microcontroller provided in an embodiment of this application; Figure 4 The working principle of the reciprocal voltage-frequency converter and the streaming-frequency converter provided in the embodiments of this application; Figure 5 A flowchart illustrating the satellite common-view calibration voltage source and constant current source process provided in this application embodiment; Figure 6 A flowchart illustrating the device self-calibration mode (voltage ratio and current ratio coefficient self-calibration) process provided in this application embodiment; Figure 7 This is a flowchart illustrating the state of the device metrology calibration mode provided in this application embodiment.

[0024] Explanation of reference numerals in the attached figures: 1. First switching node; 2. Second sampling node; 3. Third switching node; 4. Fourth switching node; 5. Fifth sampling node; 6. Beidou satellite receiving module; 7. Time interval counter; 8. First analog-to-digital converter; 9. Voltage divider circuit; 10. Reference voltage source; 11. Shunt; 12. Reference constant current source; 13. Second analog-to-digital converter; 14. Signal amplification circuit; 15. Reciprocal voltage-to-frequency converter; 16. Reciprocal I / F converter; 17. Communication module; 18. MCU; 19. Pulse counter; 20. Self-calibrating frequency meter; 21. Voltage comparator; 22. Frequency counter; 23. Power calculation chip.

[0025] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0026] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0027] The collection, storage, use, processing, transmission, provision, and disclosure of relevant data and information in the technical solution of this application all comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0028] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will be described below with reference to the accompanying drawings.

[0029] This application provides a smart meter based on remote calibration using BeiDou satellite signals, such as... Figure 1 As shown, the smart meter includes a satellite co-view synchronization unit, a voltage sampling and calibration unit, a current sampling and calibration unit, a conversion unit, and a control and communication unit; their specific connection relationships are as follows: The satellite common-view synchronization unit includes a BeiDou satellite receiving module 6 and a time interval counter 7, which are used to receive satellite timing signals to achieve time synchronization and provide a time reference for sampling and calibration.

[0030] The voltage sampling and calibration unit includes a voltage divider circuit 9, a first switching node 1, a second sampling node 2, a reference voltage source 10, and a first analog-to-digital converter 8. The first switching node 1 is controlled by a host computer and is used to switch between the metering mode (node ​​upper-level path) and the calibration mode (node ​​lower-level path). The second sampling node 2 is controlled by a host computer and collects the voltage division ratio coefficient generated by the resistor voltage divider network in real time. The first analog-to-digital converter 8 is selected as an ADC chip, and the first analog-to-digital converter 8 is connected to the voltage divider circuit 9 to form a voltage sampling module.

[0031] The current sampling and calibration unit includes a shunt 11, a third switching node 3, a fourth switching node 4, a fifth sampling node 5, a reference constant current source 12, and a second analog-to-digital converter 13. The third switching node 3 and the fourth switching node 4 are controlled by a host computer to synchronously switch between metering mode (node ​​upper-level path) and calibration mode (node ​​lower-level path). The fifth sampling node 5 is controlled by a host computer to collect the shunt coefficient generated by the shunt in real time. The second analog-to-digital converter 13 is selected as an ADC chip. The shunt 11 is connected to the second analog-to-digital converter 13 through a signal amplification circuit 14 to form a current sampling module.

[0032] The conversion unit may include a V / F converter (input voltage range 0-1000V, conversion accuracy ≤0.1%FS), an I / F converter (input current range 0-500A, conversion deviation ≤0.2%FS), a reciprocal voltage-to-frequency converter 15, and a reciprocal I / F converter 16, to achieve bidirectional conversion between voltage / current signals and frequency signals. In this embodiment, the conversion unit may only include the reciprocal voltage-to-frequency converter 15 and the reciprocal I / F converter 16, which can also achieve the purpose of bidirectional conversion.

[0033] The control and communication unit includes a microcontroller and a communication module 17. The microcontroller is electrically connected to the satellite co-view synchronization unit, the first switching node 1, the second sampling node 2, the third switching node 3, the fourth switching node 4, the fifth sampling node 5, the reference voltage source 10, the reference constant current source 11, the first analog-to-digital converter 8, the second analog-to-digital converter 13, the reciprocal voltage-to-frequency converter 15, and the reciprocal I / F converter 16. The microcontroller uses an MCU18 as the main control chip (the model in this embodiment is STM32H7), and integrates a pulse counter 19, a self-calibrating frequency meter 20, a voltage comparator 21, and a frequency counter 22. The MCU18 is also connected to a power calculation chip 23, and together with the communication module 17 supporting 4G / 5G or IoT communication, it realizes data processing, command reception, and feedback.

[0034] In terms of connection, the live wire L1 is connected to the voltage sampling module in parallel through the first switching node 1, and the live wire L1 is connected to the current sampling module in series through the third switching node 3. After flowing out through the fourth switching node 4, it is connected to the inside of the meter. The communication module 17 is remotely connected to the host computer.

[0035] In specific implementation, combined with Figure 2As shown, the laboratory-end integrated standard module has a highly integrated structure. Its core components include: a laboratory-end BeiDou satellite receiving module, a laboratory-end standard voltage source (0.01-level accuracy), a laboratory-end standard constant current source (0.01-level accuracy, output range 0-500A), a laboratory-end time interval counter, a laboratory-end pulse counter, and a laboratory-end communication module. The laboratory-end standard voltage source differs from the field-end reference voltage source; the former serves as a high-precision calibration benchmark, while the latter is the object being calibrated. Similarly, the laboratory-end standard constant current source is distinguished from the field-end reference constant current source. Although the names of the laboratory-end BeiDou satellite receiving module, time interval counter, pulse counter, and communication module are similar to their corresponding field-end modules, they are independently configured devices, each performing different functions: the field-end module receives satellite signals and provides a time benchmark and data acquisition for its own sampling and calibration, while the laboratory-end module performs common-view comparison with the field end, providing benchmark data for measurement traceability. All the above components are integrated into the same housing. A data link is established between the laboratory-end communication module and the field-end remote calibration smart energy meter, providing a traceability benchmark for the field end. The structure is simple and the operation is convenient.

[0036] The host computer visualization management system is deployed in the laboratory and equipped with a dedicated human-machine interface. It connects with all field-end remote calibration smart meters through a communication network, supports centralized visualization management, and can display the model, installation location, current working status (in use / out of payment / idle) of each meter in real time, as well as the working mode (metering mode / self-calibration mode), calibration coefficient, metering error and other key information of the remote calibration smart meters. It also supports the issuance of calibration commands and the storage and query of historical data.

[0037] In this embodiment, as Figure 3 As shown, the microcontroller is configured to perform the following steps S201-S204: S201: In response to a calibration command received from the host computer via the communication module, switch between self-calibration mode and metrology mode.

[0038] In this embodiment, the microcontroller listens in real time for calibration commands from the laboratory host computer via a communication module. The communication module uses 4G / 5G or IoT communication protocols to establish an encrypted data link with the host computer. When the microcontroller receives a calibration command from the host computer, it first parses the command type. If the command requires entering self-calibration mode, the microcontroller switches its internal working status flag to self-calibration mode and records the switching timestamp; if the command requires entering metering mode, it switches to metering mode. When no explicit command is received, the microcontroller maintains the current working mode by default and periodically reports the current mode status to the host computer to ensure synchronization between the host and host computers. Furthermore, the microcontroller can also autonomously trigger mode switching based on a preset time strategy or the meter's idle state, without waiting for commands from the host computer.

[0039] S202: When in self-calibration mode, first perform frequency calibration on the reciprocal voltage-frequency converter and the reciprocal I / F converter. Then, using the reciprocal voltage-frequency converter, the reciprocal I / F converter, the reference voltage source, and the reference constant current source calibrated by the satellite common-view synchronization unit, measure and correct the actual voltage division ratio coefficient and the actual current division ratio coefficient.

[0040] When the microcontroller executes self-calibration mode, it first performs frequency calibration on the reciprocal voltage-to-frequency converter and the reciprocal I / F converter. Taking the reciprocal voltage-to-frequency converter as an example, the microcontroller controls the satellite common-view synchronization unit to output a standard second pulse signal as a time reference. A known reference voltage is input, and the forward conversion circuit of the reciprocal voltage-to-frequency converter converts the reference voltage into a square wave pulse signal whose frequency is proportional to the voltage. Simultaneously, a time interval counter measures the time interval between the rising edge of the second pulse and the square wave pulse, and a pulse counter counts the number of pulses in each second pulse cycle to calculate the initial standard frequency. Then, the forward and reverse conversion coefficients are calculated and stored. Afterward, the microcontroller acquires the current frequency in real time. If the current frequency is not equal to the initial standard frequency, the reciprocal voltage-to-frequency converter is switched to reverse mode. A discrimination frequency equal to the initial standard frequency is input, generating a discrimination voltage. A voltage comparator compares the reference voltage and the discrimination voltage to determine the direction of change in the conversion coefficients. Then, the forward conversion coefficient is adjusted sequentially to approach the initial forward conversion coefficient, repeating the correction until the frequency deviation is zero, and the stored conversion coefficients are updated. The frequency calibration process for the reciprocal I / F converter is similar, except that the voltage is replaced with a current. After frequency calibration, the microcontroller uses the calibrated reciprocal voltage-to-frequency converter, the reciprocal I / F converter, and the reference voltage source and reference constant current source calibrated by satellite common-view to measure and correct the actual voltage division ratio and the actual current shunt ratio: the output voltage of the reference voltage source is controlled to enter the voltage divider circuit, and after voltage division, a sampled voltage is obtained. The two voltage channels are then turned on through the second sampling node, and the two voltage signals are sequentially sent to the reciprocal voltage-to-frequency converter, converted into corresponding frequency signals, and the actual voltage division ratio is calculated and corrected according to the frequency ratio. Similarly, the output current of the reference constant current source is controlled, and a voltage drop is generated through the shunt to obtain two sampled voltages. These are then turned on through the fifth sampling node and converted into corresponding frequency signals by the reciprocal voltage-to-frequency converter. The actual current shunt ratio is calculated and corrected according to the frequency ratio. The above correction update frequency can be 100ms / time to ensure the real-time accuracy of the sampling coefficients.

[0041] S203: When in metering mode, control the first, third and fourth switching nodes to switch to the metering path, and dynamically correct the voltage and current signals collected by the first analog-to-digital converter and the second analog-to-digital converter based on the corrected actual voltage division ratio coefficient and the actual current division ratio coefficient, and calculate the electrical energy.

[0042] In this embodiment, when the microcontroller is in metering mode, it controls the first, third, and fourth switching nodes to switch to the metering path, thus connecting the direct path between the live wire and the voltage sampling module, as well as the current sampling loop. In the voltage sampling channel, the voltage signal from the live wire is attenuated by a voltage divider circuit and then sent to the first analog-to-digital converter (ADC) to be converted into a digital signal. The microcontroller obtains the corrected actual voltage division ratio coefficient in real time through the second sampling node, dynamically reconstructs the attenuated digital voltage value, and obtains the original voltage value multiplied by the actual voltage division ratio coefficient. In the current sampling channel, the current flows through the shunt to generate a potential difference, which is amplified by a signal amplifier circuit and then sent to the second ADC to be converted into a digital signal. The microcontroller obtains the corrected actual shunt ratio coefficient in real time through the fifth sampling node, dynamically reconstructs the sampled current value, and obtains the original current value multiplied by the actual shunt ratio coefficient. The microcontroller uses a trapezoidal integral algorithm to calculate the total electrical energy, with a sampling interval of no more than fifteen seconds and a truncation error controlled within an extremely low range. During the calculation process, the microcontroller monitors the instantaneous values ​​of voltage and current in real time and dynamically compensates for changes in the sampling coefficient caused by temperature and load fluctuations, ensuring the accuracy of the metering results.

[0043] S204: Upload the measurement data and calibration results to the host computer via the communication module.

[0044] In this embodiment, after the microcontroller completes the acquisition of metering data or updates the calibration results, it packages the data according to a preset communication protocol. The metering data includes, but is not limited to, instantaneous voltage, instantaneous current, active power, total energy, and the currently used voltage divider ratio and current divider ratio. The calibration results include correction records for each conversion coefficient in self-calibration mode, a confirmation flag indicating that the frequency deviation has returned to zero, and a calibration timestamp. The microcontroller uploads the packaged data to the laboratory host computer via the communication module using an encrypted protocol. The upload frequency is configurable, typically uploading real-time metering data once per second, and uploading the calibration results immediately after each self-calibration. Simultaneously, the microcontroller receives confirmation commands or new calibration parameters from the host computer. If a communication failure occurs during the upload process, the microcontroller temporarily stores the data in its local non-volatile memory and automatically re-uploads it after communication is restored, ensuring data integrity. After receiving the data, the laboratory host computer updates the corresponding meter parameters in real time on the human-machine interface and determines whether the metering error exceeds the preset threshold. If it does, an automatic pop-up alarm is triggered, and the meter's location is identified. Simultaneously, maintenance personnel can issue new calibration commands to the meter via the host computer.

[0045] In some embodiments, when the microcontroller executes self-calibration mode, it first performs self-calibration of the reciprocal V / F converter and the reciprocal I / F converter, such as... Figure 4The diagram shown illustrates the working principle of the reciprocal voltage-to-frequency and current-to-frequency converters provided in this embodiment. The self-calibration process of the reciprocal V / F converter and the reciprocal I / F converter is as follows: steps ① and ②.

[0046] ① After the reciprocating V / F converter (voltage-frequency bidirectional conversion) module starts up, it first completes hardware status detection and configuration of the MCU's I / O interface, timer, and communication interface. Then it switches to forward mode and inputs the reference voltage. The satellite common-view module receives atomic clock signals from the BeiDou satellite and outputs a second pulse signal, which is then converted into an initial voltage signal by a voltage-frequency circuit. The signal is converted into a continuous square wave pulse signal with a frequency proportional to the voltage. A time interval counter is used to measure the time interval between the rising edges of the second pulse and the square wave pulse. The pulse counter counts the number of pulses in the i-th second. According to the formula Calculate the initial voltage standard frequency Then through and Solve for the initial voltage forward (voltage-frequency) and initial voltage reverse (frequency-voltage) initial conversion coefficients. ,Will , The initial voltage forward / reverse conversion coefficient is stored in the data storage unit; under normal conditions, the module maintains forward mode; subsequently, the MCU collects the current frequency in real time at preset intervals. and In comparison, if If an error is detected, switch to reverse mode and input the same as... Equal voltage discrimination frequency (numerically) ), generate discrimination voltage Compare using a voltage comparator and :like Then determine the current voltage forward conversion coefficient. Increase, current voltage reverse conversion factor Decrease; if Then determine Reduce Enlarge; then make Towards To align with and correct, to make the corrected The corrected frequency is obtained by applying it to the forward mode. According to the formula Calculate the frequency deviation, if Then repeat the correction until... It updates the correction parameters in the data storage unit, completes real-time calibration, and requires no manual on-site operation throughout the process, realizing automated bidirectional conversion and precise calibration of voltage and frequency.

[0047] ②The current conversion principle is similar. After the reciprocating I / F converter (current-frequency bidirectional conversion) module is started, it completes the hardware and interface configuration, and inputs the reference current in forward mode. After being synchronized by the satellite common-view module, the pulse is converted into a proportional square wave pulse through a current-frequency reversible circuit and then collected. and according to Calculate and store initial parameters; monitor and collect the current frequency in real time during routine monitoring. Switch to reverse input mode in case of an error. generate Determined by current comparator Trend changes, corrected to The parameters are updated afterward, enabling automated bidirectional conversion and precise calibration of current and frequency without manual intervention.

[0048] Specifically, the reference current is obtained by using the second pulse signal output by the satellite common-view synchronization unit as the time reference. Measure the time interval between the rising edges of the second pulse and the converted square wave pulse. and the number of pulses in the i-th second ,according to Calculate the initial standard current frequency, and then calculate the initial current forward conversion factor. and the reverse conversion coefficient of the initial current Get the current frequency ,like If an anomaly is detected, switch to reverse mode and, based on the... Current discrimination frequency with equal values Generate discrimination current ,contrast and :like This will increase the forward conversion factor of the current current and decrease the reverse conversion factor of the current current. This will decrease the current forward conversion factor and increase the current reverse conversion factor; the current forward conversion factor will be converted back to the initial current forward conversion factor. By approximating and correcting, the corrected current frequency is obtained. Calculate the current frequency deviation ,like Then repeat the correction until... .

[0049] In some embodiments, such as Figure 5The diagram shows the process flow for the satellite common-view calibration of the voltage source and constant current source, as improved in this embodiment. The calibration of the reference voltage source and reference constant current source involves waiting for the reciprocal V / F converter and reciprocal I / F converter to complete their self-calibration before calibrating the reference voltage source and reference constant current source using the satellite common-view method. ① The workflow for satellite common-view calibration voltage is as follows: Using the BeiDou satellite synchronization clock signal as a non-physical standard transmission medium, the entire system is divided into a laboratory standard end and a field calibration end. The standard voltage source at the laboratory standard end and the voltage source at the field calibration end establish a consistent time reference by receiving a unified 1pps second pulse signal from the satellite synchronization clock source. Subsequently, the DC voltages at both ends are converted into continuous square wave pulse signals with a frequency proportional to the voltage by a calibrated, standard-compatible reciprocal V / F converter. The time interval counter, frequency counter, and pulse counter are started simultaneously to measure the rise time interval between the satellite second pulse and the converted pulse signal, the frequency of the converted pulse signal, and the number of pulses in each second pulse cycle. At the same time, the voltage-frequency conversion coefficient at both ends is recorded. (Laboratory standard end) (On-site calibration end), based on the unified time reference provided by satellite common viewing, the collected data (sum of the maximum and minimum time intervals) from the laboratory standard end and the on-site calibration end are combined. Or the difference between adjacent time intervals Pulse count The data is transmitted to the host computer via the network and then substituted into the remote measurement model. The voltage deviation between the two ends is calculated to achieve remote and precise calibration of the voltage source being calibrated. For example, after the laboratory host computer calculates the voltage deviation between the standard and the calibrated ends, it converts this deviation value into a calibration compensation value and sends it to the field smart meter via the network. Upon receiving the calibration command, the field microcontroller automatically adjusts the output voltage parameters of the reference voltage source according to the sign and magnitude of the voltage deviation, bringing the output value of the calibrated voltage source closer to the laboratory standard voltage source. After adjustment, the microcontroller verifies the calibration effect again through satellite common-view comparison. If a deviation still exists, it is repeated until the deviation meets the accuracy requirements, thus achieving remote and precise calibration of the voltage source being calibrated.

[0050] ② The current calibration principle is similar, and its workflow is as follows: A time reference is established using the BeiDou 1pps second pulse. A high-precision I / F converter converts the DC current at both ends into a proportional square wave pulse. Relevant time, frequency, pulse count, and conversion coefficient are simultaneously acquired. The data is transmitted over the network to the host computer and substituted into the corresponding model to calculate the current deviation. This process enables remote and precise calibration of the current source under calibration, meeting metrological traceability requirements. For example, after calculating the current deviation between the standard and calibrated terminals, the laboratory's host computer converts the deviation value into calibration compensation parameters and sends them to the field smart meter via the network. Upon receiving the calibration command, the field microcontroller automatically corrects the output current value of the reference constant current source based on the direction and magnitude of the current deviation, gradually approximating the output of the laboratory's standard constant current source. After correction, the microcontroller performs a common-view comparison for confirmation, iteratively adjusting as necessary until the current deviation is eliminated, completing the remote and precise calibration of the current source under calibration.

[0051] In some embodiments, such as Figure 6 The diagram shown is a flowchart of the device self-calibration mode (voltage ratio and current ratio coefficient self-calibration) process improved in this application embodiment. In the self-calibration mode, the voltage ratio coefficient is adjusted in the following manner. , split ratio coefficient Perform calibration: A calibrated, standard reference voltage source, through its output voltage The voltage is fed into a resistor divider network, which divides the voltage into a sampling voltage. Node 2 is controlled to conduction via a host computer software algorithm. and The channel sequentially feeds the two voltage signals into a reciprocating V / F converter, converting them into frequency signals proportional to the voltage. (correspond )and (correspond ); then the precise measurements obtained and The data is transmitted to the MCU together; the MCU then uses the formula... The actual voltage division ratio of the resistive voltage divider is calculated and dynamically stored in real time, thereby correcting deviations from the theoretical voltage division ratio. Finally, the power metering chip uses the calibrated actual voltage division ratio to measure the sampled voltage. It restores the original voltage signal accurately, enabling remote automated self-calibration of the resistor divider without the need for an external reference source or manual intervention.

[0052] The principle of current calibration is the same, with the reference current source output. A voltage drop is generated across the shunt, and the sampling voltage corresponding to the reference current is obtained across the shunt. and Node 5 is controlled to conduct through a host computer software algorithm. and The channel is converted into a corresponding frequency signal by a reciprocal V / F converter. / MCU according to The actual shunt ratio is calculated and corrected. The power metering chip restores the original signal based on the calibrated shunt ratio and sampled current, realizing remote automatic self-calibration of the shunt without the need for external reference or manual intervention.

[0053] At this point, the self-calibration mode stage has calculated the partial pressure ratio coefficient. Flow split ratio calibration Finish.

[0054] In some embodiments, such as Figure 7 The diagram shown is a state flowchart of the improved device metering calibration mode in this application embodiment. In metering mode, when the meter is in working state, the first switching node 1, the third switching node 3, and the fourth switching node 4 are all controlled by the host computer to realize the connection of the node host path. In the voltage sampling channel, the voltage signal of the live wire L1 is attenuated by the voltage divider circuit and then sent to the 16-bit ADC chip to be converted into a digital signal. The MCU collects the voltage division ratio coefficient in real time through node 2 and corrects the voltage division ratio coefficient in real time by combining the dynamic compensation algorithm. This restores the attenuated signal to its original voltage value. In the current sampling channel, the current flows through the shunt to generate a potential difference, which is converted into a digital signal by the ADC chip. The MCU acquires the shunt coefficient in real time through node 5 and corrects the shunt ratio coefficient in real time using a linear compensation algorithm. Restored to the original current value The MCU employs a trapezoidal integral algorithm (sampling interval ≤ 15s, truncation error ≤ 0.005%) to measure instantaneous power. By integrating over time, the total electrical energy can be obtained. After the metering mode operation ends, the comparison data is uploaded to the host computer in real time, realizing online monitoring of the metering.

[0055] In addition, the laboratory host computer receives the uploaded data from all remotely calibrated smart energy meters in real time through the communication module. The human-computer interaction interface displays information such as the model, location, working status, working mode, real-time metering error, and calibration coefficient of each meter. Staff can remotely issue calibration instructions and view historical data to achieve large-scale centralized management.

[0056] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A smart meter based on remote calibration of Beidou satellite signals, characterized in that, include: The satellite common-view synchronization unit is used to receive BeiDou satellite signals and output standard second pulse signals to provide a unified time reference for electricity meters. The voltage sampling and calibration unit includes a voltage divider circuit, a first switching node, a second sampling node, a reference voltage source, and a first analog-to-digital converter. The input terminal of the voltage divider circuit is connected to a live wire, and its output terminal is connected to a metering path and a calibration path via the first switching node. The second sampling node is connected to the sampling terminal of the voltage divider circuit and is used to collect the actual voltage division ratio coefficient of the voltage divider circuit. The current sampling and calibration unit includes a shunt, a third switching node, a fourth switching node, a fifth sampling node, a reference constant current source, and a second analog-to-digital converter. The shunt is connected in series in the live wire loop, and its two ends are connected to the metering path or the calibration path via the third switching node and the fourth switching node, respectively. The fifth sampling node is connected to the voltage sampling terminal of the shunt and is used to collect the actual shunt ratio coefficient of the shunt. The conversion unit includes a reciprocating voltage-to-frequency converter and a reciprocating I / F converter; the reciprocating voltage-to-frequency converter is used to realize bidirectional conversion between voltage signals and frequency signals, and the reciprocating I / F converter is used to realize bidirectional conversion between current signals and frequency signals. The control and communication unit includes a microcontroller and a communication module; the microcontroller is electrically connected to the satellite common-view synchronization unit, the first switching node, the second sampling node, the third switching node, the fourth switching node, the fifth sampling node, the reference voltage source, the reference constant current source, the first analog-to-digital converter, the second analog-to-digital converter, the reciprocal voltage-to-frequency converter, and the reciprocal I / F converter, and is configured as follows: In response to a calibration command received from the host computer via the communication module, the system switches between self-calibration mode and metrology mode. When in self-calibration mode: First, the frequency of the reciprocal voltage-frequency converter and the reciprocal I / F converter is calibrated. Then, the actual voltage division ratio coefficient and the actual current division ratio coefficient are measured and corrected using the reciprocal voltage-frequency converter, the reciprocal I / F converter, the reference voltage source and the reference constant current source calibrated by the satellite common-view synchronization unit. When in metering mode: control the first, third, and fourth switching nodes to switch to the metering path, and dynamically correct the voltage and current signals collected by the first analog-to-digital converter and the second analog-to-digital converter based on the corrected actual voltage division ratio coefficient and the actual current division ratio coefficient, and calculate the electrical energy. The measurement data and calibration results are uploaded to the host computer through the communication module.

2. The smart meter based on Beidou satellite signal remote calibration according to claim 1, characterized in that, The microcontroller is further configured to perform frequency calibration on the reciprocating voltage-to-frequency converter in the following manner: Taking the second pulse signal outputted by the satellite common view synchronization unit as the time reference, the initial voltage is obtained , the time interval between the rising edges of the second pulse and the converted back wave pulse is measured , and the number of pulses in the i-th second is measured , the initial standard voltage frequency is calculated according to the formula , the initial voltage forward conversion coefficient and the initial voltage reverse conversion coefficient are calculated ; Get the current voltage frequency ,like If an anomaly is detected, switch to reverse mode and, based on the... Voltage discrimination frequency with equal values Generate discrimination voltage ,contrast and :like Then let the current voltage forward conversion coefficient be... Increase the current voltage reverse conversion factor If it becomes smaller Then let the current voltage forward conversion coefficient be... Decreasing, current voltage reverse conversion factor Get bigger; The current voltage forward conversion factor Positive conversion coefficient to the initial voltage of storage By approximating and correcting, the corrected voltage frequency is obtained. Calculate voltage frequency deviation ,like Then repeat the correction until... .

3. The smart meter based on remote calibration using BeiDou satellite signals according to claim 1, characterized in that, The microcontroller is further configured to perform frequency calibration on the reciprocal I / F converter in the following manner: The reference current is obtained by using the second pulse signal output by the satellite common-view synchronization unit as the time reference. Measure the time interval between the rising edges of the second pulse and the converted square wave pulse. and the number of pulses in the i-th second ,according to Calculate the initial standard current frequency, and then calculate the initial current forward conversion factor. and the reverse conversion coefficient of the initial current ; Get current frequency ,like If an anomaly is detected, switch to reverse mode and, based on the... Current discrimination frequency with equal values Generate discrimination current ,contrast and :like This will increase the forward conversion factor of the current current and decrease the reverse conversion factor of the current current. This will decrease the forward conversion factor of the current current and increase the reverse conversion factor of the current current; Convert the current forward conversion factor to the initial current forward conversion factor. By approximating and correcting, the corrected current frequency is obtained. Calculate the current frequency deviation ,like Then repeat the correction until... .

4. The smart meter based on remote calibration using BeiDou satellite signals according to claim 1, characterized in that, The microcontroller is further configured to measure and correct the actual partial pressure ratio coefficient in the following manner: Control the output voltage of the reference voltage source The sampled voltage is obtained after voltage division in the voltage divider circuit. Control the second sampling node to turn on. and The channel sequentially feeds the two voltage signals into the reciprocating voltage-to-frequency converter, converting them into corresponding frequency signals. and The actual partial pressure ratio coefficient is calculated using the following formula. And store corrections: 。 5. The smart meter based on remote calibration using BeiDou satellite signals according to claim 1, characterized in that, The microcontroller is further configured to measure and correct the actual shunt ratio coefficient in the following manner: Control the output current of the reference constant current source The voltage drop generated by the shunt results in a corresponding sampling voltage across the shunt. and Control the fifth sampling node to turn on. and The channel is converted into a corresponding frequency signal by the reciprocal frequency converter. and The actual split ratio coefficient is calculated using the following formula. And store corrections: 。 6. The smart meter based on remote calibration using BeiDou satellite signals according to claim 1, characterized in that, The microcontroller is further configured to calibrate the reference voltage source and the reference constant current source in the following manner: The communication module receives calibration data from a standard voltage source in the laboratory. Using the BeiDou satellite synchronous clock signal as the time reference, the voltage deviation between the calibrated voltage source and the standard voltage source is calculated according to the remote metrology model. : in, , These are the voltage-frequency conversion coefficients for the laboratory standard terminal and the field calibration terminal, respectively. , These represent the sum of the maximum and minimum time intervals between the laboratory standard terminal and the field calibration terminal, respectively.

7. The smart meter based on remote calibration using BeiDou satellite signals according to claim 1, characterized in that, When the microcontroller is further configured to execute metering mode, the total electrical energy is calculated using the following formula: in, This is the original voltage sample value. This is the original current sampling value. This is the actual partial pressure ratio coefficient. This is the actual split ratio coefficient. and These are the upper and lower limits of the integral, respectively. It is a time variable.

8. The smart meter based on remote calibration using BeiDou satellite signals according to claim 1, characterized in that, The microcontroller is also configured to: execute a self-calibration mode once every set time when the meter is in working condition; and continuously execute the self-calibration mode when the meter is in an arrears-paid idle state.

9. The smart meter based on remote calibration using BeiDou satellite signals according to claim 1, characterized in that, When the microcontroller interacts with the remote host computer through the communication module, the data transmission adopts an encryption protocol; when the measurement error exceeds the preset threshold, the host computer automatically pops up an alarm and locates the meter position.

10. The smart meter based on remote calibration using BeiDou satellite signals according to claim 1, characterized in that, The voltage divider circuit includes a 200:1 voltage divider circuit composed of metal foil resistors; the shunt is a 0.05-level standard shunt; the first analog-to-digital converter and the second analog-to-digital converter are both ADC chips.

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