Clock time keeping and time service method for intelligent electric meter
By combining high-precision punctuality and long-wave timing technology, smart meters can maintain high-precision timing in multiple scenarios, solving the problem of timing deviation in the long-term operation of the meter and ensuring the accuracy of power metering.
Patent Information
- Application Number
- CN202411815549.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-03-14
AI Technical Summary
There is a timing deviation problem in smart meters during long-term operation, which affects the accuracy of electricity metering.
The method of combining high-precision punctuality and long-wave timing is adopted to obtain high-precision clock signals through the temperature-compensated crystal oscillator, and the long-wave timing module is used to receive the timing signals in the atmosphere for calibration, so as to achieve high-precision punctuality and synchronization of the clock.
It significantly improves the timing accuracy of smart meters, ensures the reliability of electricity metering, and solves the timing deviation problem in the long-term operation of the meter.
Smart Images
Figure CN119620583A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of smart electric meters, and more particularly to a clock calibration method applied to smart electric meters. Background Art
[0002] At present, the clocks of electric meters in China all use real-time clocks. According to industry standards, the accuracy of the clock of electric meters is required to meet 1s / d within the operating temperature range of the meter. At a normal temperature of 23°C, the clock accuracy of the meter must meet 0.5s / d. When the meter is working, the aging of the crystal oscillator itself and environmental factors such as temperature and humidity will cause the crystal oscillator frequency to deviate, thereby increasing the error of the RTC clock of the meter.
[0003] At present, most meters are calibrated by broadcast time or by a host computer. The former is easily affected by noise in the power grid, while the latter has major defects in real-time performance and accuracy.
[0004] However, the timing accuracy of smart meters is crucial to energy measurement, but there is a timing deviation problem in long-term operation. The crystal oscillator of the meter RTC system will produce frequency drift due to factors such as temperature, resulting in the accumulation of timing errors. At the same time, there may also be deviations between the meter clock and the standard time. These deviations will affect the accuracy of energy measurement.
[0005] How to maintain high-precision timing during the long-term operation of the meter and keep it synchronized with standard time is a complex technical challenge. Summary of the invention
[0006] The purpose of the present invention is to solve the problem of maintaining high precision of the real-time clock of an electric energy meter, and to propose a clock timekeeping and timing method for an intelligent electric meter that combines high-precision timekeeping and long-wave timing, thereby ensuring that the real-time clock of the electric energy meter runs accurately in multiple scenarios.
[0007] The technical solution of the present invention is:
[0008] The present invention provides a clock timekeeping and timing method for a smart meter, wherein the smart meter comprises a metering core and a management core; the metering core is connected to a timekeeping module, and the management core is connected to a long-wave timing module and an expansion module. The method comprises the following steps:
[0009] Timing steps: measure the frequency of the input clock of the external temperature-compensated crystal oscillator in one cycle, obtain the system clock deviation based on the frequency deviation, and then correct the system frequency deviation through the frequency deviation compensation value;
[0010] Long-wave timing steps: Receive the timing signal in the atmosphere through the long-wave timing module, convert the received timing signal into a high- and low-level pulse sequence, send it to the expansion module for filtering and decoding to obtain the time information, and send the time information to the metering core through the dual-core synchronous interface of the smart meter to complete the time calibration.
[0011] Furthermore, the time keeping step is specifically as follows:
[0012] Measure the frequency F of the external temperature-compensated crystal oscillator in one cycle, and calculate the frequency deviation ΔF and time deviation ΔT. The time deviation ΔT of the frequency F of the external temperature-compensated crystal oscillator is equal to the system RTC clock deviation. Use the following formula to obtain the system RTC clock deviation ΔN:
[0013]
[0014] ΔN=0.1*(F-10);
[0015] The frequency deviation compensation value DFi is calculated using the following formula;
[0016]
[0017] The target value is corrected by the frequency deviation compensation value DFi to correct the frequency deviation of the system.
[0018] Furthermore, the timing step is specifically as follows:
[0019] Initialize the long-wave timing module, detect whether the level remains low within the first preset time, and switch to high level after the first preset time, use this as the frame header, and start receiving time code information;
[0020] After receiving 1 frame of data, decode the data;
[0021] The decoded time information is sent to the metering core of the smart meter to complete the clock time synchronization.
[0022] Furthermore, the first preset time is 900ms.
[0023] Furthermore, after receiving the timing signal in the atmosphere, the long-wave timing module performs filtering processing to extract a valid signal.
[0024] Furthermore, in the timing step, the filtering and decoding processing by the filter extension module to obtain the time information specifically includes:
[0025] Divide the received pulse high level time into multiple intervals, corresponding to different binary codes respectively;
[0026] It is determined whether the expansion module can decode successfully for multiple times in a row within the second preset time. If the decoding time interval is consistent with the timing, it is determined that the decoding is successful, and the time information is sent to the metering core for synchronization.
[0027] Furthermore, the second preset time is 5 minutes.
[0028] Furthermore, the metering core is used for electric energy metering, clock management and data storage, and the management core is used for human-computer interaction, communication management and fee control management.
[0029] Furthermore, the long-wave timing module includes a cylindrical ferrite antenna, a front-end amplifier, a tuned amplifier, an AGC gain control circuit and a detection circuit: the front-end amplifier and the tuned amplifier are used to receive the long-wave timing signal, and the gain of the front-stage amplifier is adjusted by the rear-end AGC gain control circuit and the detection circuit, and the processed timing signal is converted into a regular high and low level pulse sequence.
[0030] Furthermore, in the timing step: the frequency of the clock signal of the external temperature-compensated crystal oscillator is 10 MHz; the crystal oscillator of the smart meter RTC system is 32.768 KHz.
[0031] Beneficial effects of the present invention:
[0032] The present invention obtains a high-precision clock signal through a temperature-compensated crystal oscillator, measures the frequency deviation of the RTC crystal oscillator, calculates and calibrates the time deviation of the real-time clock to achieve a high-precision timekeeping function, and does not require external equipment to calibrate the clock of the meter.
[0033] The present invention uses a long-wave timing module to receive and demodulate the timing signal, extract standard time information to calibrate the meter clock. When multiple timing information is received within a preset time period, the present invention can also determine the accuracy of the timing information and select the most accurate information for calibration. The long-wave timing station is a relatively reliable high-precision timing system currently used in my country, with a signal accuracy within ±1 microsecond; the system uses the propagation characteristics of long waves, which propagate on the surface and in the ionosphere in the atmosphere. This timing method can provide timing for the electric energy meter in terms of coverage area and signal propagation characteristics.
[0034] The method of the present invention integrates two technologies, namely, RTC crystal oscillator frequency calibration and long-wave timing calibration, which not only ensures the long-term stability of the meter clock, but also realizes synchronization with the standard time; through the multiple calibration mechanism, the timing accuracy of the smart meter is significantly improved, a reliable time reference is provided for electric energy measurement, and the timing deviation problem in the long-term operation of the meter is effectively solved.
[0035] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.
[0037] Figure 1 It is a principle block diagram of the smart meter of the present invention.
[0038] Figure 2 It is a schematic block diagram of the high-precision timekeeping of the present invention.
[0039] Figure 3 It is a schematic diagram of time code analysis in the long-wave timing step of the present invention. DETAILED DESCRIPTION
[0040] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.
[0041] The present invention provides a timekeeping and timing method for a smart meter clock, wherein the smart meter is Figure 1 As shown, it includes a metering core and a management core; the metering core is connected to a timekeeping module, and the management core is connected to a long-wave timing module and an expansion module. The method includes the following steps;
[0042] Timing steps: measure the frequency of the input clock of the external temperature-compensated crystal oscillator in one cycle, obtain the system clock deviation based on the frequency deviation, and then correct the system frequency deviation through the frequency deviation compensation value;
[0043] Long-wave timing steps: Receive the timing signal in the atmosphere through the long-wave timing module, convert the received timing signal into a high- and low-level pulse sequence, send it to the expansion module for filtering and decoding to obtain the time information, and send the time information to the metering core through the dual-core synchronous interface of the smart meter to complete the time calibration.
[0044] In this embodiment, the 10MHz output of the meter's TCXO temperature compensated crystal oscillator is used as a reference, and the meter's RTC is calibrated in real time to achieve high-precision timekeeping. When the meter time deviation is large, the external timing module calibrates the meter accurately and quickly in real time, so that the smart meter can ensure high-precision time operation in multiple scenarios.
[0045] In one example, the time keeping step is specifically as follows:
[0046] Measure the frequency F of the external temperature-compensated crystal oscillator in one cycle, and calculate the frequency deviation ΔF and time deviation ΔT. The time deviation ΔT of the frequency F of the external temperature-compensated crystal oscillator is equal to the system RTC clock deviation. Use the following formula to obtain the system RTC clock deviation ΔN:
[0047]
[0048] ΔN=0.1*(F-10);
[0049] The frequency deviation compensation value DFi is calculated using the following formula;
[0050]
[0051] The target value is corrected by the frequency deviation compensation value DFi to correct the frequency deviation of the system.
[0052] In one example, the timing step is specifically as follows:
[0053] Initialize the long-wave timing module, detect whether the level remains low within 900ms, and switch to high level after 900ms, using this as the frame header to start receiving time code information;
[0054] After receiving 1 frame of data, decode the data;
[0055] Divide the received pulse high level time into multiple intervals, corresponding to different binary codes respectively;
[0056] Determine whether the expansion module can successfully decode multiple times within 5 minutes. If the decoding time interval is consistent with the timing, it is determined that the decoding is successful and the time information is sent to the metering chip for synchronization.
[0057] Specifically, the timing module communicates with the expansion module of the smart meter, and the timing module is powered by an external battery. The main implementation method of the timing part of the present invention is to detect the signal output by the timing module through the expansion module, decode it, and then pass it to the metering core to complete the timing. When the high and low levels output by the timing module are sent to the expansion module, the expansion module recognizes the high level of the signal and decodes it according to the principle of BPC encoding. The schematic diagram of decoding is shown in FIG. Figure 3 shown.
[0058] First, determine whether the received timing signal maintains a low level for about 1s. If so, continue to receive the subsequent fixed-length time coding information. If not, continue to wait until the complete frame header information is received before receiving the subsequent time code information. In reality, the long-wave timing signal is limited by factors such as weather, terrain, and climate, and the signal quality may be affected. Therefore, a suitable filtering algorithm is needed to filter the waveform emitted by the timing module, filter out clutter, and improve the signal-to-noise ratio.
[0059] Long-wave timing signals contain time information. In these pulses, the pulse widths of 100ms, 200ms, 300ms, and 400ms correspond to quaternary 0, 1, 2, and 3, respectively, and to binary 00, 01, 10, and 11. The algorithm divides the effective high-level time of the received pulse into multiple intervals: 50ms-145ms, 150ms-245ms, 250ms-345ms, and 350ms-445ms. The levels of these intervals correspond to 100ms, 200ms, 300ms, and 400ms, respectively.
[0060] The specific operation of the filtering algorithm is as follows: when the expansion module decodes successfully for the first time, it records the current decoding time, performs timing, and continues the decoding operation. If the subsequent decoding is successful, the subsequent decoding time is compared with the first decoding time to determine whether the time difference between the two is consistent with the timing time. Continuous decoding is required within 5 minutes, and the decoding must be correct at least twice before the expansion module determines that the decoding is successful and sends the decoded time information to the metering core for time synchronization.
[0061] In one example, the metering core is used for power metering, clock management and data storage, and the management core is used for human-computer interaction, communication management and fee control management;
[0062] The long-wave timing module comprises a cylindrical ferrite antenna, a front-end amplifier, a tuned amplifier, an AGC gain control circuit and a detection circuit: the front-end amplifier and the tuned amplifier are used to receive long-wave timing signals, and the gain of the front-stage amplifier is adjusted by the rear-end AGC gain control circuit and the detection circuit, and the processed timing signal is converted into a regular high and low level pulse sequence.
[0063] When implementing:
[0064] A high-precision clock signal output by a temperature-compensated crystal oscillator is obtained, wherein the frequency of the high-precision clock signal is 10 MHz; and a frequency deviation of a 32.768 KHz crystal oscillator of a smart meter within one cycle is measured using the high-precision clock signal to obtain a frequency deviation value.
[0065] According to the frequency deviation value, the time deviation value of the real-time clock of the smart meter is calculated; according to the time deviation value, the real-time clock of the smart meter is calibrated to obtain a calibrated high-precision real-time clock.
[0066] The long-wave timing signal in the atmosphere is received by the long-wave timing module, and the long-wave timing signal is demodulated to obtain timing information. The validity of the timing information is determined, and if the timing information is valid, the standard time information in the timing information is extracted.
[0067] The standard time information is sent to a metering module of the smart meter, and the high-precision real-time clock of the smart meter is calibrated according to the standard time information to obtain a smart meter clock after timing calibration.
[0068] If multiple valid timing information is received within a preset time period, the decoding time and timing information of the multiple timing information are compared to determine the accuracy of the timing information, and the timing information with the highest accuracy is selected to calibrate the smart meter clock.
[0069] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.
Claims
1. A timekeeping and timing method for a smart meter clock, characterized in that: The smart electric meter comprises a metering core and a management core; the metering core is connected to a timekeeping module, and the management core is connected to a long-wave timing module and an expansion module. The method comprises the following steps; Timing steps: measure the frequency of the input clock of the external temperature-compensated crystal oscillator in one cycle, obtain the system clock deviation based on the frequency deviation, and then correct the system frequency deviation through the frequency deviation compensation value; Long-wave timing steps: Receive the timing signal in the atmosphere through the long-wave timing module, convert the received timing signal into a high- and low-level pulse sequence, send it to the expansion module for filtering and decoding to obtain the time information, and send the time information to the metering core through the dual-core synchronous interface of the smart meter to complete the time calibration.
2. The method for keeping time and providing time for a smart meter clock according to claim 1, characterized in that: The time keeping steps are specifically as follows: Measure the frequency F of the external temperature-compensated crystal oscillator in one cycle, and calculate the frequency deviation ΔF and time deviation ΔT. The time deviation ΔT of the frequency F of the external temperature-compensated crystal oscillator is equal to the system RTC clock deviation. Use the following formula to obtain the system RTC clock deviation ΔN: ΔN=0.1*(F-10); The frequency deviation compensation value DFi is calculated using the following formula; The target value is corrected by the frequency deviation compensation value DFi to correct the frequency deviation of the system.
3. The time keeping and timing method for a smart meter clock according to claim 1, characterized in that: The timing steps are specifically as follows: Initialize the long-wave timing module, detect whether the level remains low within the first preset time, and switch to high level after the first preset time, use this as the frame header, and start receiving time code information; After receiving 1 frame of data, decode the data; The decoded time information is sent to the metering core of the smart meter to complete the clock time synchronization.
4. The method for keeping time and providing time for a smart meter clock according to claim 3, characterized in that: The first preset time is 900ms.
5. The time keeping and timing method for a smart meter clock according to claim 3, characterized in that: After receiving the timing signal in the atmosphere, the long-wave timing module performs filtering processing to extract the effective signal.
6. The time keeping and timing method for a smart meter clock according to claim 5, characterized in that: In the timing step, the filtering and decoding processing by the filter extension module to obtain the time information specifically includes: Divide the received pulse high level time into multiple intervals, corresponding to different binary codes respectively; It is determined whether the expansion module can successfully decode multiple times in a row within the second preset time. If the decoding time interval is consistent with the timing, it is determined that the decoding is successful, and the time information is sent to the metering core for synchronization.
7. The time keeping and timing method for a smart meter clock according to claim 6, characterized in that: The second preset time is 5 minutes.
8. The time keeping and timing method for a smart meter clock according to any one of claims 1 to 7, characterized in that: The metering core is used for electric energy metering, clock management and data storage, and the management core is used for human-computer interaction, communication management and fee control management.
9. The time keeping and timing method for a smart meter clock according to claim 8, characterized in that: The long-wave timing module comprises a cylindrical ferrite antenna, a front-end amplifier, a tuned amplifier, an AGC gain control circuit and a detection circuit: the front-end amplifier and the tuned amplifier are used to receive long-wave timing signals, and the gain of the front-stage amplifier is adjusted by the rear-end AGC gain control circuit and the detection circuit, and the processed timing signal is converted into a regular high and low level pulse sequence.
10. The time keeping and timing method for a smart meter clock according to claim 1, characterized in that In the timing step: the frequency of the clock signal of the external temperature-compensated crystal oscillator is 10MHz; the crystal oscillator of the smart meter RTC system is 32.768KHz.