A low-power consumption measurement method for an electric energy meter in a power-off state

Abstract

This invention discloses a method for measuring low power consumption in an electricity meter under power failure conditions, belonging to the field of low power consumption detection technology for electricity meters. The method includes the following components: S1, initial factory temperature calibration and basic data acquisition; S2, second factory temperature calibration and comparative data acquisition; S3, establishing a temperature-sampled value-low power consumption correlation curve; S4, real-time sampling and temperature derivation after power failure; and S5, low power consumption value correction calculation and display. This invention, through environmental consistency calibration technology and multiple temperature calibrations, combined with a weighted correction algorithm, establishes two correlation curves: temperature sampled value-meter internal temperature and meter internal temperature-low power consumption. This effectively improves the temperature measurement accuracy of the electricity meter under power failure conditions. Simultaneously, it employs abnormal data fault tolerance technology and dual-path redundancy control technology to ensure the continuity of backup power supply and the reliability of measurement data after power failure, maintaining high measurement accuracy even in complex environments.

Description

Technical Field

[0001] This invention relates to the field of low power consumption detection technology for electricity meters, specifically a method for measuring low power consumption of electricity meters in the power-off state. Background Technology

[0002] With the rapid development of smart grids, electricity meters, as core equipment for electricity metering and management, directly affect the operating efficiency of the power system and the quality of service for users. In practical applications, electricity meters often face abnormal situations such as power outages. At this time, electricity meters need to rely on backup power to maintain basic functions, such as data recording and time retention.

[0003] Traditional electricity meters often employ a single temperature correction model for low-power measurements during power outages. This model ignores the impact of power supply voltage fluctuations and component temperature sensitivity on the measurement results, leading to significant measurement errors. Furthermore, traditional methods lack high-precision calibration techniques and anti-interference measures for temperature measurement, making it difficult to guarantee accuracy in complex environments. In addition, backup power switching mechanisms often carry the risk of single-point failures; a failure in the switching device will cause the entire measurement system to shut down, severely impacting the reliability and data integrity of the electricity meter. Regarding data storage, traditional methods lack effective encryption and verification mechanisms, compromising data security and recoverability.

[0004] In view of the shortcomings of traditional technologies in measuring low power consumption of electricity meters when the power is off, this invention proposes a method for measuring low power consumption of electricity meters when the power is off, which is of particular importance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for measuring low power consumption in the power-off state of an electricity meter. This method establishes high-precision correlation curves between temperature sampling values ​​and internal meter temperature, and between internal meter temperature and low power consumption, through environmental consistency calibration technology and multiple temperature calibrations combined with a weighted correction algorithm. This effectively improves temperature measurement accuracy. Simultaneously, it employs anomaly data fault tolerance technology and dual-path redundancy control technology to ensure the continuity of backup power supply and the reliability of measurement data. Furthermore, through temperature compensation algorithms and real-time sampling values ​​of backup power supply voltage, it achieves accurate correction of low power consumption values. Combined with wake-up-sleep adaptive technology for the display circuit, it effectively reduces the power consumption of the display circuit and extends the operating time of the backup power supply.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for measuring low power consumption in an electricity meter under power-off conditions, the specific steps of which are as follows: S1. First temperature calibration and basic data acquisition before leaving the factory: Using the environmental consistency calibration process, the first calibration temperature T1 is set, and the energy meter is placed in this constant temperature environment for a preset time. After the energy meter is powered on, the power detection circuit samples the backup power supply voltage to obtain V1. After filtering and voltage division, it is input into the MCU to calculate the real-time power supply voltage V2. The temperature measurement circuit samples simultaneously to obtain V3. The MCU records the low-power reference value P1 and stores the relevant data through a combination of encrypted backup and hierarchical storage. S2. Second temperature calibration and comparison data acquisition before leaving the factory: Continue the environmental consistency calibration process, switch to the second calibration temperature T2, keep other states unchanged, the power detection circuit samples V1' and calculates V2', the temperature measurement circuit samples V3', and the MCU records and stores the low power consumption value P2. S3. Establish temperature-sampled value-low power consumption curves: The MCU calls the calibration data twice, uses a weighted correction algorithm to establish and store two correlation curves: temperature sampled value-in-table temperature and in-table temperature-low power consumption. S4. Real-time sampling and temperature derivation after power failure: Automatic switching of backup power supply is achieved through dual-path redundancy control technology. The temperature measurement circuit uses shielded sampling and multi-dimensional filtering technology to collect real-time sampled values ​​V3”. The power detection circuit uses multi-cycle synchronous verification technology to sample V1” and calculate V2”. The MCU derives the current temperature T based on the corresponding curve and abnormal data fault tolerance technology. S5. Low power consumption value correction calculation and display: The MCU queries the correction curve based on the current temperature T, and uses the temperature compensation algorithm combined with V2” correction to obtain the low power consumption value P. The storage circuit manages the data through hierarchical storage and cyclic overlay technology. The display circuit adopts wake-up-sleep adaptive technology, which can be triggered by preset operation to display P.

[0007] Furthermore, the factory calibration process employs environmental consistency calibration technology. The specific steps are as follows: Before calibration, the energy meter is placed in a high-precision constant temperature chamber. The chamber temperature is first set to 25℃ and stabilized for 2 hours. Then, a standard temperature sensor is used to calibrate the installation position of the internal temperature measuring circuit. The output deviation value of the temperature measuring circuit is recorded and stored in the MCU. During the first calibration, T1=25℃ is set, and the temperature fluctuation of the constant temperature chamber is controlled within ±0.2℃. The energy meter is powered on and preheated for 30 minutes before sampling is started to ensure stable circuit operation. The second calibration is performed at T2=60℃. During calibration, the constant temperature chamber is heated to 60℃ at a rate of 5℃ / minute and stabilized for 2 hours before sampling to avoid instability of component characteristics caused by sudden temperature changes. During the two calibration processes, the low power consumption values ​​P1 and P2 of the energy meter are measured using a high-precision power analyzer and used as calibration reference values. After calibration, the energy meter is placed in a 40℃ environment to stabilize for 1 hour and a verification measurement is performed. If the deviation between the derived low power consumption value and the measured value exceeds ±2%, the calibration is repeated. This technology ensures the initial accuracy of the temperature-low power consumption curve by optimizing the calibration environment control and reference value calibration process.

[0008] Furthermore, the curve corresponding to the temperature sample value and the temperature in the table in S3 is established using a weighted correction algorithm, the formula of which is: ,in This is the real-time temperature inside the electricity meter after a power outage. This refers to the voltage sampling value collected in real time by the temperature measuring circuit after a power outage. For the second calibration temperature The voltage sampling value of the lower temperature measurement circuit. , Temperature weighting coefficient, The accuracy calibration coefficient for the temperature measurement circuit is derived by fitting the nominal accuracy of the thermistor NTC1 with the temperature coefficient of the low-temperature drift resistor R20. The correction factor for the influence of power supply voltage is determined by the ratio of V2 to V2' in the two calibrations. This is the nominal resistance value of R20. The resistance deviation of R20 at the actual calibration temperature is calculated by the difference between the resistance value of R20 measured by a high-precision instrument at T1 and T2 before leaving the factory and the nominal value. The environmental adaptability correction factor, ranging from 0.98 to 1.02, is determined based on the gradient fitting of the difference between the common transportation and storage temperature range of the electricity meter and the calibration temperature range. The baseline temperature offset of the system is determined by calibrating the output deviation value of the temperature measuring circuit under a standard constant temperature environment of 0℃. This ensures the mapping accuracy between the sampled value and the temperature in different temperature ranges. The algorithm breaks through the limitations of traditional linear mapping and achieves accurate temperature derivation over a wide temperature range through multi-dimensional parameter weighting.

[0009] Furthermore, the power detection circuit in S4 employs multi-cycle synchronous verification technology for real-time sampling of the backup power supply voltage. The specific implementation steps are as follows: the MCU controls the power detection circuit to continuously collect 5 sets of voltage sampling values ​​with a sampling cycle of 10ms; each set of sampling values ​​is filtered to remove abnormal data exceeding ±3% of the average value; the arithmetic mean of the remaining valid sampling values ​​is calculated as the final V1”; the voltage change rate ΔV of adjacent sampling cycles is detected synchronously. If ΔV > 0.5%, the sampling cycle is automatically increased to 5ms, and 10 sets of data are continuously sampled before re-filtering and calculation; after sampling, the MCU compares V1” with the factory-calibrated V2 and V2'. If the deviation between V1” and V2 exceeds ±10%, a power stability warning is triggered. Simultaneously, the voltage-power consumption correction coefficient table of the backup power supply in the storage circuit is called for secondary calibration to ensure the accuracy of the power sampling values ​​in supporting temperature derivation and power consumption calculation. This technology solves the sampling error problem caused by backup power supply voltage fluctuations by dynamically adjusting the sampling frequency and the abnormal data removal mechanism.

[0010] Furthermore, the anti-interference optimization of the temperature measurement circuit in S4 adopts a combination of shielded sampling and multi-dimensional filtering technology. The specific implementation steps are as follows: In the PCB routing stage of the temperature measurement circuit, the voltage divider circuit area composed of NTC1 thermistor, R20 low-temperature drift resistor and filter capacitor C27 is wrapped with a metal shielding layer, and the shielding layer is grounded to reduce external electromagnetic interference; the MCU processes the temperature measurement sampling value V3” using a dual mechanism of hardware filtering + software filtering. At the hardware level, high-frequency interference is filtered out through C27, and at the software level, a moving average filtering algorithm is used to sort the 10 consecutive sets of sampling values ​​in chronological order and remove the maximum and minimum values. The average of the remaining 8 sets of data is calculated as the effective sampled value V3. During the sampling process, the MCU synchronously detects the power supply voltage VCC of the temperature measuring circuit. If the VCC fluctuation exceeds ±2%, the current sampling is paused and restarted after VCC stabilizes. At the same time, every 30 sets of effective sampled values ​​are collected, and trend analysis is performed on them. If the rate of change of 5 consecutive sets of data exceeds ±2℃ / s, it is determined to be abnormal interference. The interference correction table of the same model of energy meter temperature measuring circuit is called in the storage circuit for compensation. This technology effectively reduces the impact of electromagnetic interference and voltage fluctuation on temperature measurement accuracy, and controls the temperature measurement error within ±0.3℃.

[0011] Furthermore, the derivation of the current temperature T in S4 employs anomaly data fault tolerance technology. The specific implementation steps are as follows: After the MCU calls the temperature sampling value - the corresponding curve of the meter temperature to derive the current temperature T, it immediately compares T with the operating temperature limit range of the energy meter. If T exceeds this range, it is determined to be a sampling anomaly. At this time, the MCU controls the temperature measurement circuit to re-collect three sets of V3" data, deriving three temperature values ​​T1~T3 respectively, and calculating the variance of the three temperature values. If the variance ≤ 0.5℃², the average value is taken as the final T; if the variance > 0.5℃², the average value is taken as the final T. If the temperature reaches ℃², the pre-stored backup temperature curve in the storage circuit is invoked. Based on the statistical average characteristics of the same batch of energy meters, the backup temperature is derived by combining the current V2” value. At the same time, the MCU stores the abnormal sampling information in the storage circuit and uploads the abnormal information to the background management system the next time the energy meter is powered on. If five consecutive samples are determined to be abnormal, a fault prompt is triggered in the temperature measurement circuit, and Err-T is displayed cyclically through the display circuit. This technology effectively copes with abnormal temperature derivation caused by instantaneous interference or minor faults in the temperature measurement circuit, and improves the robustness of the measurement system.

[0012] Furthermore, the backup power supply switching employs dual-path redundancy control technology. The specific implementation steps are as follows: A main switching diode D5 and a backup switching diode D6 are set in the power switching circuit, connected in reverse parallel between the backup power supply output terminal and the system power supply bus. When the energy meter is powered on, the 5V power supply terminal monitors the output voltage in real time through a voltage detection circuit. When the 5V voltage stabilizes in the 4.8V~5.2V range, the MCU outputs a control signal to cut off the backup power supply circuit. At this time, both the main and backup diodes are in the off state. When the 5V voltage is detected to be lower than 4.5V, the MCU immediately triggers a backup power supply switching command, and the main switching diode... Diode D5 is turned on first, while the backup diode D6 is in standby mode. During the switching process, the MCU monitors the system power supply bus voltage in real time. If the bus voltage is lower than 3.0V and lasts for more than 200μs, the main switching diode is determined to be faulty, the backup diode D6 is immediately turned on, and the fault information is stored in the storage circuit. In the power-off state, the MCU monitors the backup power supply voltage every minute. When the voltage is lower than 3.2V, the control display circuit flashes to indicate low power. This redundant switching technology ensures the continuity and reliability of backup power supply after power failure and avoids the measurement system from shutting down due to the failure of a single switching device.

[0013] Furthermore, the correction calculation of the low power consumption value P in S5 adopts a temperature compensation algorithm, and the formula is as follows: ,in This represents the precise low-power consumption value at the current temperature after the electricity meter loses power. For the first calibration temperature The low power consumption reference value for the electricity meter. For the second calibration temperature The low power consumption value of the electricity meter. This is the initial factory calibration temperature. This is the second factory calibration temperature. The slope of the temperature-power-based change. This refers to the backup power supply voltage value collected in real time by the power supply detection circuit after a power outage. For the first calibration temperature The real-time voltage value of the backup power supply. This is the difference between the real-time temperature and the initial calibration temperature. This represents the percentage of voltage fluctuation in the backup power supply. This is the difference between the real-time temperature and the reference temperature. The power supply voltage fluctuation compensation coefficient is determined based on the allowable fluctuation range between the rated voltage and the actual operating voltage of the backup power supply. It is obtained by fitting the coefficient after repeatedly changing the backup power supply voltage and measuring the rate of change of power consumption. The temperature sensitivity compensation coefficient is determined based on the power consumption temperature sensitivity curve of the core components of the electricity meter. It is obtained by supplementing the calibration at five intermediate temperature points between T1 and T2, and then fitting the coefficient using the least squares method. Using temperature as a reference, this formula integrates three major influencing factors: temperature difference, power supply voltage fluctuation, and component temperature sensitivity, to achieve accurate correction of low power consumption values. Compared with the traditional single temperature correction model, the error is reduced by more than 40%.

[0014] Furthermore, the data storage of the storage circuit adopts encrypted backup and verification technology. The specific implementation steps are as follows: when storing factory calibration data and real-time measurement data, the data is encrypted using the AES-128 encryption algorithm. The encryption key is generated by combining the unique hardware serial number of the energy meter with the SHA-256 hash algorithm. The storage circuit is divided into a main storage area and a backup storage area. The main storage area stores the data updated in real time, and the backup storage area synchronously updates the data in the main storage area every 30 minutes. At the same time, after each data write, a 16-bit CRC check code is generated and stored at the end of the corresponding data block. Each time the MCU reads data, it first calculates the CRC check code of the read data and compares it with the stored check code. If they do not match, the corresponding data is read from the backup storage area, and the main storage area data is marked as abnormal. When the data in the backup storage area also fails to be verified, the MCU automatically calls the factory-preset default curve parameters for calculation and displays a data abnormality prompt through the display circuit. This technology ensures the security, integrity, and recoverability of critical data and avoids measurement failure due to storage failure.

[0015] Furthermore, the low-power control of the display circuit in S5 adopts a wake-up-sleep adaptive technology. The specific implementation steps are as follows: In the power-off state, the display circuit is in sleep mode by default, retaining only the level detection function of the scrolling display button. At this time, the power consumption of the display circuit is controlled below 1μA. When a trigger signal of pressing and holding the scrolling display button for 3 seconds is detected, the MCU outputs a wake-up command to the display circuit. The display circuit starts and loads the stored current low-power value P, displaying it in a clear digital format for a duration of 10 seconds. During the display period, if the scrolling display button is pressed again, the display time will be interrupted. The timeout period is extended to 30 seconds. After the timeout, the MCU automatically outputs a sleep command to the display circuit, shutting off the power supply to the display driver module and retaining only the button detection function. At the same time, the MCU adjusts the display brightness according to the backup power supply voltage. When the backup power supply voltage is higher than 3.4V, the display brightness is 100%; when the voltage is between 3.2V and 3.4V, the display brightness drops to 50%; when the voltage is lower than 3.2V, the display brightness drops to 30%. This technology minimizes the power consumption of the display circuit and extends the working time of the backup power supply while ensuring the display function.

[0016] Compared with existing technologies, this low-power measurement method for electricity meters in the power-off state has the following advantages: I. This invention establishes two correlation curves—one between the temperature sampling value and the internal temperature, and the other between the internal temperature and low power consumption—through environmental consistency calibration technology and multiple temperature calibrations, combined with a weighted correction algorithm. This effectively improves the temperature measurement accuracy of the energy meter under power failure conditions. At the same time, it employs abnormal data fault tolerance technology and dual-path redundancy control technology to ensure the continuity of backup power supply and the reliability of measurement data after power failure, maintaining high measurement accuracy even in complex environments.

[0017] Second, this invention uses a temperature compensation algorithm combined with real-time sampling of backup power supply voltage to accurately correct low power consumption values, avoiding the errors of traditional single temperature correction models and achieving precise management of low power consumption values. At the same time, the display circuit adopts wake-up-sleep adaptive technology, which minimizes the power consumption of the display circuit while ensuring display function, effectively extending the working time of backup power supply and improving the overall energy efficiency and reliability of the electricity meter.

[0018] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0020] Figure 1 This is a low-power measurement method for electricity meters in the power-off state; Figure 2 This is a low-power measurement method for electricity meters in the power-off state; Figure 3 This is a low-power measurement method for electricity meters in the power-off state. Detailed Implementation

[0021] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0022] Example 1 Before leaving the factory, the electricity meter undergoes its first calibration according to the environmental consistency calibration process. The electricity meter is first placed in a high-precision constant temperature chamber, with the initial temperature set at 25℃. The electricity meter is allowed to stabilize in this constant temperature environment for 2 hours, during which the temperature fluctuation of the constant temperature chamber is strictly controlled within ±0.2℃. Then, the electricity meter is powered on and preheated for 30 minutes before sampling is started. The power detection circuit samples the backup power supply voltage to obtain the original voltage value V1. V1 is filtered and divided before being input to the MCU, which calculates the real-time power supply voltage V2. At the same time, the temperature measurement circuit samples synchronously to obtain the voltage sampling value V3. The MCU records the low power consumption reference value P1 of the electricity meter at this time and uses the AES-128 encryption algorithm to encrypt the relevant data such as P1, V2, and V3. Then, through a combination of encrypted backup and hierarchical storage, the encrypted data is stored in the main storage area of ​​the storage circuit.

[0023] Following the environmental consistency calibration process, a second calibration was performed. The temperature of the constant temperature chamber was switched to 60℃, while keeping other operating states of the energy meter unchanged. After the temperature chamber was heated to 60℃ at a rate of 5℃ / minute, the energy meter was allowed to stabilize at this temperature for 2 hours before sampling was initiated. During the sampling process, the power detection circuit sampled the backup power supply voltage to obtain V1', which was then processed and calculated by the MCU to obtain V2'. The temperature measurement circuit simultaneously sampled to obtain V3'. The MCU recorded the low power consumption value P2 of the energy meter at this time and stored the data such as V2', V3', and P2 using the same encryption and storage method as the first calibration. After calibration, the energy meter was placed in a 40℃ environment and stabilized for 1 hour for verification measurement. The deviation between the derived low power consumption value and the measured value was within ±2%, indicating that the calibration result was valid. Figure 2 As shown.

[0024] Before the electricity meter leaves the factory, the MCU calls the first and second calibration data and uses a weighted correction algorithm to establish two correlation curves: one between the temperature sampling value and the internal temperature of the meter, and the other between the internal temperature of the meter and the low power consumption. The formula is as follows: ,in This is the real-time temperature inside the electricity meter after a power outage. This refers to the voltage sampling value collected in real time by the temperature measuring circuit after a power outage. For the second calibration temperature The voltage sampling value of the lower temperature measurement circuit. , Temperature weighting coefficient, This is the accuracy calibration coefficient for the temperature measurement circuit. This is a correction factor for the influence of power supply voltage. This is the nominal resistance value of R20. This represents the resistance deviation of R20 at the actual calibration temperature. This is the environmental adaptability correction factor. To measure the system baseline temperature offset, after the curves are established, both curve data are stored in the storage circuit according to the same encrypted storage rules, providing data support for subsequent measurements after power failure. Figure 1 As shown.

[0025] During household use, if the mains power suddenly fails, the electricity meter will trigger a power-down state. At this time, the power switching circuit uses dual-path redundancy control technology to automatically switch to backup power: in the power switching circuit, the main switching diode D5 and the backup switching diode D6 are connected in reverse parallel between the backup power output terminal and the system power supply bus. After the mains power is interrupted, the voltage at the 5V power supply terminal drops below 4.5V, and the MCU immediately triggers the backup power switching command. The main switching diode D5 is turned on first, and the backup diode D6 is in standby mode. At the same time, the MCU monitors the system power supply bus voltage in real time.

[0026] During the sampling phase, the temperature measurement circuit employs a combination of shielded sampling and multi-dimensional filtering techniques to acquire real-time sampled values ​​V3”. In the PCB routing phase, the voltage divider circuit area composed of the NTC1 thermistor, R20 low-temperature drift resistor, and filter capacitor C27 in the temperature measurement circuit is encased in a metal shield and grounded. At the hardware level, C27 filters out high-frequency interference. At the software level, a moving average filtering algorithm is used to sort 10 consecutive sets of sampled values ​​in chronological order, remove the maximum and minimum values, and calculate the average of the remaining 8 sets of data as the valid sampled value V3”. During the sampling process, the MCU synchronously monitors the power supply voltage VCC of the temperature measurement circuit. If the VCC fluctuation does not exceed ±2%, sampling continues. Trend analysis is performed every 30 sets of valid sampled values, and no abnormal situation occurred where the rate of change of 5 consecutive sets of data exceeded ±2℃ / s.

[0027] The power detection circuit uses multi-cycle synchronous verification technology to sample V1”: The MCU controls the power detection circuit to continuously collect 5 sets of voltage sampling values ​​with a sampling cycle of 10ms. After filtering each set of sampling values, abnormal data exceeding ±3% of the average value are removed. The arithmetic mean of the remaining valid sampling values ​​is calculated as the final V1”, and then V2” is calculated by the MCU. The voltage change rate ΔV of adjacent sampling cycles is detected synchronously. If ΔV does not exceed 0.5%, there is no need to adjust the sampling cycle. Then, V1” is compared with the factory-calibrated V2. If the deviation does not exceed ±10%, there is no need to trigger a power stability warning.

[0028] Finally, the MCU, based on the stored temperature measurement sample value - meter internal temperature corresponding curve and combined with abnormal data fault tolerance technology, derives the current meter internal temperature T: The derived T is compared with the operating temperature limit range of the energy meter; if T is within the normal range, the sampling is deemed valid, and the current temperature T is finally determined. Figure 3 As shown.

[0029] Based on the derived current temperature T, the MCU queries the stored temperature-low power correction curve and applies a temperature compensation algorithm, the formula of which is: ,in This represents the precise low-power consumption value at the current temperature after the electricity meter loses power. For the first calibration temperature The low power consumption reference value for the electricity meter. For the second calibration temperature The low power consumption value of the electricity meter. This is the initial factory calibration temperature. This is the second factory calibration temperature. The slope of the temperature-power-based change. This refers to the backup power supply voltage value collected in real time by the power supply detection circuit after a power outage. For the first calibration temperature The real-time voltage value of the backup power supply. This is the difference between the real-time temperature and the initial calibration temperature. This represents the percentage of voltage fluctuation in the backup power supply. This is the difference between the real-time temperature and the reference temperature. This is the power supply voltage fluctuation compensation coefficient. This is the temperature-sensitive compensation coefficient. Using the reference temperature and the V2” calculated in real time, the low power consumption value is corrected, and finally the accurate low power consumption value P at the current temperature after the power meter is lost is obtained.

[0030] The storage circuit manages data through hierarchical storage and cyclic overwrite technology: the main storage area updates P and related sampling data in real time, and the backup storage area updates the main storage area data synchronously every 30 minutes. After each data write, a 16-bit CRC check code is generated and stored at the end of the corresponding data block.

[0031] The display circuit adopts wake-up-sleep adaptive technology: In the power-off state, the display circuit is in sleep mode by default, only retaining the level detection function of the scrolling display button. At this time, the power consumption of the display circuit is controlled below 1μA. When the user presses and holds the scrolling display button for 3 seconds, the MCU detects the trigger signal and outputs a wake-up command to the display circuit. The display circuit starts and loads the stored current low power value P, which is displayed in a clear digital format. The display duration is set to 10 seconds. If the user does not press the scrolling display button again during the timeout, the MCU automatically outputs a sleep command to the display circuit after the display timeout, turns off the power supply to the display driver module, and retains only the button detection function.

[0032] Example 2 During the factory calibration phase of the electricity meter, the first temperature calibration is performed. The electricity meter is placed in a high-precision constant temperature chamber, and the temperature of the chamber is set to 25°C. After stabilizing for 2 hours, a standard temperature sensor is used to calibrate the installation position of the internal temperature measuring circuit. The output deviation value of the temperature measuring circuit is recorded and stored in the MCU. Then, the temperature of the constant temperature chamber is maintained at 25°C, and the electricity meter is powered on and preheated for 30 minutes before sampling is started. The power detection circuit samples the backup power supply voltage to obtain V1. After filtering and voltage division, the MCU calculates V2. The temperature measuring circuit simultaneously samples to obtain V3. The high-precision power analyzer measures the low power consumption reference value P1 at this time. After the MCU records P1, all relevant data is encrypted using the AES-128 encryption algorithm and stored in the storage circuit through a combination of encrypted backup and hierarchical storage.

[0033] Following the environmental consistency calibration procedure, a second calibration was performed. The target temperature of the constant temperature chamber was set to 60℃, and the temperature was increased to 60℃ at a rate of 5℃ / minute, then stabilized for 2 hours. After sampling was initiated, the power detection circuit sampled V1' and the MCU calculated V2', the temperature measurement circuit sampled V3', and the high-precision power analyzer measured the low power consumption value P2. The MCU recorded and encrypted the relevant data. After calibration, the energy meter was placed in a 40℃ environment and stabilized for 1 hour for verification measurement. The deviation between the derived low power consumption value and the measured value was ±1.5%, which meets the requirement of ≤±2%, indicating that the calibration was valid. Figure 2 As shown.

[0034] The MCU retrieves all data acquired during the two calibrations and uses a weighted correction algorithm to construct two correlation curves: one between the temperature sample value and the internal temperature, and the other between the internal temperature and low power consumption. The curve data is encrypted and stored in a storage circuit, providing an accurate data model for power-down measurements in industrial environments. Figure 1 As shown.

[0035] The industrial workshop experienced a power outage due to equipment maintenance, causing the electricity meter to go into a power-down state. The power switching circuit immediately activated dual-path redundancy control: the 5V power supply voltage rapidly dropped below 4.5V, the MCU triggered a backup power switching command, the main switching diode D5 turned on, and the MCU monitored the system power supply bus voltage in real time. No voltage drop below 3.0V for more than 200μs was observed, and the backup diode D6 remained in standby mode.

[0036] Temperature measurement circuit sampling starts: Due to electromagnetic interference in the workshop environment, the temperature measurement circuit initially filters out interference through a metal shielding layer and C27 hardware filtering. At the software level, the sampling data is processed according to the moving average filtering algorithm. After collecting 10 sets of data, the extreme values ​​are removed, and the average value of the remaining 8 sets is taken as V3”. During the sampling process, the MCU detected a fluctuation of ±1.8% in the power supply voltage VCC of the temperature measurement circuit, which did not exceed ±2%, so there was no need to stop sampling. After collecting 30 sets of valid sampling values, trend analysis was performed, and it was found that the change rate of 3 consecutive sets of data was close to ±2℃ / s, but did not exceed the threshold, so interference compensation was not triggered.

[0037] The power supply detection circuit continuously collects 5 sets of V1” data with a sampling period of 10ms. After filtering, one set of abnormal data exceeding the average value by ±3% is removed. The arithmetic mean of the remaining 4 sets is calculated as the final V1”, and V2” is derived. The synchronous detection voltage change rate ΔV is 0.6%. If it exceeds 0.5%, the sampling period is automatically adjusted to 5ms. After continuously sampling 10 sets of data, the data is re-filtered and calculated to finally obtain a stable V2”. V2” is compared with the factory-calibrated V2. The deviation is ±8%, which does not exceed ±10%, so there is no need to trigger a power supply stability warning.

[0038] The MCU calls the temperature sampling value and the internal temperature curve to derive the current temperature T. Finding that T is close to the upper limit of the energy meter's operating temperature, it immediately compares T with the limit range and determines that it is within the range. However, to ensure accuracy, according to the abnormal data fault tolerance technical requirements, the temperature measuring circuit is controlled to re-collect three sets of V3 data, deriving three temperature values ​​T1~T3 respectively. The variance of the three temperature values ​​is calculated to be 0.3℃², ≤0.5℃², and the average value is taken as the final current temperature T. Figure 1 As shown.

[0039] Based on the final determined current temperature T, the MCU queries the correction curve, uses a temperature compensation algorithm, and combines real-time V2” to correct the low power consumption value. It fully considers factors such as the slope of the temperature-power consumption base change, the proportion of backup power supply voltage fluctuation, and the difference between real-time temperature and reference temperature, and finally obtains an accurate low power consumption value P.

[0040] The storage circuit manages data using hierarchical storage and cyclic overlay technology. The main storage area updates P and related sampling data, and the backup storage area is updated synchronously. At the same time, a 16-bit CRC check code is generated and stored. When the MCU reads the data later, it first calculates the CRC check code of the read data and compares it with the stored check code to ensure data consistency.

[0041] The display circuit is in sleep mode by default, with power consumption controlled below 1μA. Workshop staff can wake the display circuit by pressing and holding the scrolling display button for 3 seconds. The display circuit will then load and display "P". If the staff briefly presses the scrolling display button within 10 seconds, the display duration will be extended to 30 seconds. After the timeout, the display circuit will automatically go into sleep mode and return to low-power mode. During power outages, the MCU monitors the backup power supply voltage every minute, and the voltage remains above 3.2V, without triggering a low-battery flashing warning.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A low-power consumption measurement method for an electric energy meter in a power-off state, characterized in that, The specific steps of this method are as follows: S1. First temperature calibration and basic data acquisition before leaving the factory: Using the environmental consistency calibration process, the first calibration temperature T1 is set, and the energy meter is placed in this constant temperature environment for a preset time. After the energy meter is powered on, the power detection circuit samples the backup power supply voltage to obtain V1. After filtering and voltage division, it is input into the MCU to calculate the real-time power supply voltage V2. The temperature measurement circuit samples simultaneously to obtain V3. The MCU records the low-power reference value P1 and stores the relevant data through a combination of encrypted backup and hierarchical storage. S2. Second temperature calibration and comparison data acquisition before leaving the factory: Continue the environmental consistency calibration process, switch to the second calibration temperature T2, keep other states unchanged, the power detection circuit samples V1' and calculates V2', the temperature measurement circuit samples V3', and the MCU records and stores the low power consumption value P2. S3. Establish temperature-sampled value-low power consumption curves: The MCU calls the calibration data twice, uses a weighted correction algorithm to establish and store two correlation curves: temperature sampled value-in-table temperature and in-table temperature-low power consumption. S4. Real-time sampling and temperature derivation after power failure: Automatic switching of backup power supply is achieved through dual-path redundancy control technology. The temperature measurement circuit uses shielded sampling and multi-dimensional filtering technology to collect real-time sampled values ​​V3”. The power detection circuit uses multi-cycle synchronous verification technology to sample V1” and calculate V2”. The MCU derives the current temperature T based on the corresponding curve and abnormal data fault tolerance technology. S5. Low power consumption value correction calculation and display: The MCU queries the correction curve based on the current temperature T, and uses the temperature compensation algorithm combined with V2” correction to obtain the low power consumption value P. The storage circuit manages the data through hierarchical storage and cyclic overlay technology, and the display circuit adopts wake-up-sleep adaptive technology.

2. The low-power consumption measurement method for an electric energy meter in a power-off state according to claim 1, characterized in that, The factory calibration process adopts environmental consistency calibration technology. The specific implementation steps are as follows: Before calibration, the energy meter is placed in a high-precision constant temperature chamber. The temperature of the constant temperature chamber is first set to 25°C. After stabilizing for 2 hours, a standard temperature sensor is used to calibrate the installation position of the temperature measuring circuit inside the meter. The output deviation value of the temperature measuring circuit is recorded and stored in the MCU. When setting T1=25℃ for the first calibration, the temperature fluctuation of the constant temperature chamber should be controlled within ±0.2℃. The energy meter should be powered on and preheated for 30 minutes before sampling is started. When performing the second calibration at T2=60℃, the constant temperature chamber was heated to 60℃ at a rate of 5℃ / minute and stabilized for 2 hours before sampling. During both calibrations, the low power consumption values ​​P1 and P2 of the energy meter were measured using a high-precision power analyzer and used as calibration reference values. After calibration, the energy meter was placed in a 40℃ environment and stabilized for 1 hour for verification measurement. If the deviation between the derived low power consumption value and the measured value exceeded ±2%, the calibration was repeated.

3. The method for measuring low power consumption of an energy meter in a power-off state according to claim 1, characterized in that, The establishment of the temperature sampling value-in-table temperature corresponding curve in the S3 adopts a weighted correction algorithm, and the formula is: , wherein is the real-time temperature in the table after the power failure of the electric energy meter, is the voltage sampling value collected by the temperature measurement circuit in real time after the power failure, is the second calibration temperature is the voltage sampling value of the lower temperature measurement circuit, , is the temperature weight coefficient, is the precision calibration coefficient of the temperature measurement circuit, is the power voltage influence correction coefficient, is the nominal resistance value of R20, is the resistance deviation amount of R20 at the actual calibration temperature; is the environmental adaptability correction coefficient, is the system baseline temperature offset.

4. The method for measuring low power consumption of an energy meter in a power-off state according to claim 1, characterized in that, The power detection circuit in S4 uses multi-cycle synchronous verification technology for real-time sampling of the backup power supply voltage. The specific implementation steps are as follows: The MCU controls the power detection circuit to continuously collect 5 sets of voltage sampling values ​​with a sampling cycle of 10ms; each set of sampling values ​​is filtered to remove abnormal data that exceed the average value by ±3%; the arithmetic mean of the remaining valid sampling values ​​is calculated as the final V1”; the voltage change rate ΔV of adjacent sampling cycles is detected synchronously. If ΔV > 0.5%, the sampling cycle is automatically increased to 5ms, and 10 sets of data are continuously sampled before re-filtering and calculation; after sampling, the MCU compares V1” with the factory-calibrated V2 and V2'. If the deviation between V1” and V2 exceeds ±10%, a power stability warning is triggered, and the voltage-power consumption correction coefficient table of the backup power supply in the storage circuit is called for secondary calibration.

5. The method for measuring low power consumption of an energy meter in a power-off state according to claim 1, characterized in that, The anti-interference optimization of the temperature measurement circuit in S4 adopts a combination of shielded sampling and multi-dimensional filtering technology. The specific implementation steps are as follows: During the PCB routing stage of the temperature measurement circuit, the voltage divider circuit area composed of NTC1 thermistor, R20 low-temperature drift resistor and filter capacitor C27 is wrapped with a metal shielding layer, and the shielding layer is grounded; The MCU processes the temperature measurement sampling value V3” using a dual mechanism of hardware filtering + software filtering. At the hardware level, high-frequency interference is filtered out through C27. At the software level, a moving average filtering algorithm is used to sort 10 consecutive sets of sampling values ​​in chronological order, remove the maximum and minimum values, and calculate the average value of the remaining 8 sets of data as the effective sampling value V3”; During the sampling process, the MCU synchronously detects the power supply voltage VCC of the temperature measurement circuit. If the VCC fluctuation exceeds ±2%, the current sampling is paused, and sampling is restarted after VCC stabilizes; At the same time, every 30 sets of effective sampling values ​​are collected, and trend analysis is performed on them. If the change rate of 5 consecutive sets of data exceeds ±2℃ / s, it is determined to be abnormal interference, and the interference correction table of the same model of energy meter temperature measurement circuit stored in the storage circuit is called for compensation.

6. The method for measuring low power consumption of an energy meter in a power-off state according to claim 1, characterized in that, The derivation of the current temperature T in S4 adopts an abnormal data fault tolerance technology. The specific implementation steps are as follows: After the MCU calls the curve corresponding to the temperature sampling value and the temperature in the meter to derive the current temperature T, it immediately compares T with the working temperature limit range of the energy meter. If T exceeds the range, it is determined to be a sampling abnormality. At this time, the MCU controls the temperature measurement circuit to re-collect three sets of V3” data, derive three temperature values ​​T1~T3 respectively, and calculate the variance of the three temperature values. If the variance is ≤0.5℃², the average value is taken as the final T; if the variance is >0.5℃², the backup temperature curve stored in the storage circuit is called up, and the backup temperature is derived by combining it with the current V2” value. At the same time, the MCU stores the abnormal sampling information to the storage circuit, and uploads the abnormal information to the background management system the next time the energy meter is powered on. If five consecutive samples are determined to be abnormal, a fault indication is triggered in the temperature measurement circuit, and Err-T is displayed cyclically on the display circuit.

7. The method for measuring low power consumption of an energy meter in a power-off state according to claim 1, characterized in that, The backup power supply switching adopts dual-path redundancy control technology. The specific implementation steps are as follows: A main switching diode D5 and a backup switching diode D6 are set in the power switching circuit, connected in reverse parallel between the backup power supply output terminal and the system power supply bus. When the energy meter is powered on, the 5V power supply terminal monitors the output voltage in real time through a voltage detection circuit. When the 5V voltage stabilizes in the range of 4.8V~5.2V, the MCU outputs a control signal to cut off the backup power supply circuit. At this time, both the main and backup diodes are in the off state. When the 5V voltage is detected to be lower than 4.5V, the MCU immediately triggers a backup power supply switching command. The main switching diode D5 is turned on first, while the backup diode D6 is in a standby state. During the switching process, the MCU monitors the system power supply bus voltage in real time. If the bus voltage is lower than 3.0V and the duration exceeds 200μs, the main switching diode is determined to be faulty, the backup diode D6 is immediately turned on, and the fault information is stored in the storage circuit. In the power-off state, the MCU monitors the backup power supply voltage every minute. When the voltage is lower than 3.2V, the control display circuit flashes to indicate low power.

8. The method for measuring low power consumption of an energy meter in a power-off state according to claim 1, characterized in that, The correction calculation for the low power consumption value P in S5 uses a temperature compensation algorithm, and the formula is as follows: ,in This represents the precise low-power consumption value at the current temperature after the electricity meter loses power. For the first calibration temperature The low power consumption reference value for the electricity meter. For the second calibration temperature The low power consumption value of the electricity meter. This is the initial factory calibration temperature. This is the second factory calibration temperature. The slope of the temperature-power-based change. This refers to the backup power supply voltage value collected in real time by the power supply detection circuit after a power outage. For the first calibration temperature The real-time voltage value of the backup power supply. This is the difference between the real-time temperature and the initial calibration temperature. This represents the percentage of voltage fluctuation in the backup power supply. This is the difference between the real-time temperature and the reference temperature. This is the power supply voltage fluctuation compensation coefficient. This is the temperature-sensitive compensation coefficient. This is the reference temperature.

9. A method for measuring low power consumption in an energy meter under power-off conditions according to claim 1, characterized in that, The storage circuit employs encrypted backup and verification technology for data storage. The specific implementation steps are as follows: When storing factory calibration data and real-time measurement data, the AES-128 encryption algorithm is used to encrypt the data. The encryption key is generated by combining the unique hardware serial number of the energy meter with the SHA-256 hash algorithm. The storage circuit is divided into a main storage area and a backup storage area. The main storage area stores data that is updated in real time, and the backup storage area updates the main storage area data synchronously every 30 minutes. At the same time, after each data write, a 16-bit CRC check code is generated and stored at the end of the corresponding data block. Each time the MCU reads data, it first calculates the CRC checksum of the data to be read and compares it with the stored checksum. If they do not match, the corresponding data is read from the backup storage area, and the main storage area is marked as abnormal. When the data in the backup storage area also fails to be verified, the MCU automatically calls the factory-preset default curve parameters for calculation and displays a data abnormality prompt through the display circuit.

10. A method for measuring low power consumption in an energy meter under power-off conditions according to claim 1, characterized in that, The low-power control of the display circuit in S5 adopts wake-up-sleep adaptive technology. The specific implementation steps are as follows: In the power-off state, the display circuit is in sleep mode by default, only retaining the level detection function of the scrolling display button. At this time, the power consumption of the display circuit is controlled below 1μA. When a trigger signal of pressing and holding the scrolling display button for 3 seconds is detected, the MCU outputs a wake-up command to the display circuit. The display circuit starts and loads the stored current low-power value P, which is displayed in a clear digital format. The display duration is set to 10 seconds. During the display, if the scrolling display button is pressed again, the display duration is extended to 30 seconds. After the display timeout, the MCU automatically outputs a sleep command to the display circuit, turns off the power supply to the display driver module, and retains only the button detection function.

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