A voltage ripple control method and an electric energy meter

Abstract

This invention provides a voltage ripple control method and an energy meter for use in energy meters, relating to the field of power metering and load control technology. The method includes the following steps: sampling the grid voltage using an analog-to-digital converter to obtain a voltage digital signal containing ripple signals; performing digital filtering on the voltage digital signal to extract ripple signals within a specific frequency range; calculating the signal characteristics of the extracted ripple signals to convert them into a digital level signal sequence; parsing the digital level signal sequence according to a preset ripple control protocol to identify control commands; and executing corresponding control actions based on the identified control commands. This invention reduces system deployment and maintenance costs by integrating ripple control signal reception and decoding functions into the energy meter's microprocessor; supports flexible switching between multiple frequency points; and improves system maintainability.

Description

Technical Field

[0001] This invention relates to the field of power metering and load control technology, specifically to a voltage ripple control method for an electricity meter and an electricity meter. Background Technology

[0002] Power companies widely use ripple control systems for load management in power transmission and distribution services. These systems superimpose high-frequency, low-power control signals—the ripple signal—onto a normal AC voltage. This ripple signal is used to control the operation of loads such as streetlights and water heaters over a large area, or to execute other commands. The transmitting end modulates the control command into a ripple signal of a specific frequency and injects it into the power line. The receiving end needs to extract this frequency signal from the voltage data and parse the control command.

[0003] In traditional solutions, ripple control requires the deployment of a dedicated ripple receiver as a control node. This receiver exists independently of the electricity meter and is equipped with dedicated signal processing circuitry and a microprocessor for filtering, demodulating, and analyzing ripple signals. This architecture has significant drawbacks: First, dedicated hardware increases system deployment costs, as each control point requires an additional ripple receiver. Second, the maintenance cost of this independent device is high, with fault diagnosis and replacement requiring separate handling. Third, the ripple receiver and the smart meter need to interact via an interface, increasing system complexity.

[0004] In recent years, electricity meters have acquired sophisticated microprocessors and communication capabilities, but in ripple control applications, they remain passive devices, failing to fully utilize their computing and communication resources. Existing electricity meters already have internal AD converters for voltage and current sampling, and microprocessors with digital signal processing capabilities. Theoretically, these hardware resources can be used for ripple signal extraction and analysis, but currently, there is no mature technical solution to achieve this integration.

[0005] Current ripple reception technologies primarily employ analog filters or simple digital comparators for signal processing. While analog filters offer fast response times, they are susceptible to temperature and component aging, and their parameters are difficult to adjust once fixed, resulting in insufficient flexibility for applications requiring switching between multiple frequency points. Simple voltage comparison or pulse counting methods have limited fault tolerance in the presence of weak signals or interference, and fail to fully utilize the advantages of modern digital signal processing technologies.

[0006] Furthermore, the configuration parameters of traditional ripple receivers are fixed in hardware or firmware, requiring manual adjustments in the field, which cannot adapt to changes in the power grid environment or remote management needs. With the development of smart grids, power companies hope to be able to remotely and flexibly adjust the frequency, protocol type, and trigger threshold of ripple control, but the configurability of existing solutions is limited by the hardware architecture.

[0007] Chinese patent document CN107493119B discloses a DC bus carrier communication system based on VPPM utilizing power supply ripple. It discloses a technical solution that drives the converter circuit switching transistor through VPPM modulation to load data onto the DC bus ripple signal. This solution achieves the technical effect of eliminating dedicated modulation lines and reducing communication costs. However, this solution focuses on the signal modulation technology at the transmitting end and is mainly applied to DC bus carrier communication. The signal processing method at the receiving end is relatively simple, using only voltage comparators or hysteresis comparators for demodulation. The filtering accuracy and anti-interference capability are limited, and it does not involve deep integration with smart meters or remote configuration capabilities.

[0008] European patent document EP1555534A1 discloses an electronic power meter with a ripple control receiver. It discloses a technical solution that implements a digital filter in the power meter's microprocessor and uses the output of a voltage-to-digital converter to receive ripple signals. This solution achieves the technical effect of eliminating the need for independent ripple receiver hardware and reducing system costs. However, the solution does not provide detailed explanations of the design method and parameter configuration of the digital filter. It only mentions frequency-to-pulse conversion and telegraph template comparison. It lacks descriptions of specific filtering algorithms, multi-frequency support, protocol parsing details, and remote configuration functions. The operability and system flexibility of engineering implementation are still insufficient. Summary of the Invention

[0009] The purpose of this invention is to provide a voltage ripple control method and an energy meter for use in energy meters that do not require a dedicated ripple receiver, are low in cost, have stable and reliable signal processing, and support remote configuration.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A voltage ripple control method for an electricity meter, applied to an electricity meter including an analog-to-digital converter and a microprocessor, includes the following steps:

[0012] S1: Sample the grid voltage to obtain a digital voltage signal containing ripple signals;

[0013] S2: Perform digital filtering on the voltage digital signal to extract the ripple signal within a specific frequency range;

[0014] S3: Perform signal feature calculation on the extracted ripple signal and convert the ripple signal into a digital level signal sequence;

[0015] S4: Parse the digital level signal sequence according to the preset ripple control protocol and output control commands.

[0016] Further: the digital filtering process for the voltage digital signal in S2 includes:

[0017] S21: The voltage digital signal is filtered by a bandpass filter, wherein the passband frequency range of the bandpass filter is 100Hz to 1500Hz;

[0018] S22: Adjust the amplitude of the filtered signal according to a preset proportional coefficient.

[0019] Furthermore, the bandpass filter is an IIR bandpass filter, which filters the voltage digital signal through a cascaded method.

[0020] Further: the signal feature calculation of the extracted ripple signal in S3 includes:

[0021] S31; Calculate the root mean square value of the extracted ripple signal within a preset time window;

[0022] S32: Compare the root mean square value with a preset threshold. When the root mean square value is higher than the preset threshold, it is determined to be a high level. When the root mean square value is lower than or equal to the preset threshold, it is determined to be a low level.

[0023] S33: Repeat the above calculation and comparison with a sampling period of 10ms to 50ms to generate a digital level signal sequence.

[0024] Furthermore, the preset threshold is 0.5% to 5% of the effective voltage value.

[0025] Further: the step S4 of parsing the digital level signal sequence according to the preset ripple control protocol includes:

[0026] S41: Detect the start marker signal in the digital level signal sequence;

[0027] S42: Identify the data segment following the start identifier signal;

[0028] S43: Convert the level duration in the data segment into bit values ​​according to the preset protocol rules;

[0029] S44: Combine bit values ​​into control commands.

[0030] Furthermore, the preset protocol rules support at least one of the Decabit protocol and the Telenerg protocol. Different protocols define the correspondence between the level duration and the bit value through corresponding preset time parameters.

[0031] Furthermore: Before executing S1, the following is also included:

[0032] Receive remote configuration instructions and adjust the filtering frequency of digital filtering, the threshold value of signal feature calculation, or the protocol type of protocol parsing according to the remote configuration instructions.

[0033] An energy meter implementing the above method includes an analog-to-digital converter and a microprocessor, the microprocessor comprising:

[0034] A digital filtering module, the input of which is connected to the output of an analog-to-digital converter, is used to perform digital filtering on a voltage digital signal to extract ripple signals within a specific frequency range.

[0035] A signal determination module, the input of which is connected to the output of the digital filtering module, is used to perform signal feature calculation on the extracted ripple signal and convert it into a digital level signal sequence;

[0036] The protocol parsing module has its input connected to the output of the signal determination module and is used to parse the digital level signal sequence according to the preset ripple control protocol and output control commands.

[0037] The control execution module has its input connected to the output of the protocol parsing module and is used to receive control commands and control the load switch status.

[0038] Furthermore, the microprocessor also includes:

[0039] The configuration management module is connected to a remote communication interface and is used to receive remote configuration commands and adjust the filtering parameters of the digital filtering module, the threshold value of the signal determination module, or the protocol type of the protocol parsing module.

[0040] An energy calculation module, the input of which is connected to the output of an analog-to-digital converter, is used to calculate the energy consumption based on the sampling data of the analog-to-digital converter.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] I. This invention integrates the ripple control signal receiving and decoding function into the microprocessor of an electricity meter. It utilizes the existing analog-to-digital converter and microprocessor resources of the electricity meter to extract and analyze the ripple signal, allowing the electricity meter to directly control the operation of subsequent loads. Compared to traditional solutions that require additional independent ripple receiver hardware, this invention eliminates the need for dedicated equipment, saving on hardware procurement costs, installation and deployment costs, and subsequent maintenance costs.

[0043] II. This invention employs an IIR bandpass filter based on the CMSIS-DSP library for digital filtering, supporting signal extraction from multiple frequency points within a wide frequency range of 175Hz to 1500Hz. The digital filter is unaffected by temperature and component aging, exhibiting high stability. Filter parameters can be adjusted via software programming, flexibly supporting switching between different frequency points, offering greater adaptability compared to the limitations of fixed parameters in traditional analog filters.

[0044] Third, this invention utilizes the built-in remote communication function of the electricity meter to remotely adjust all key parameters of ripple reception, including filtering frequency, judgment threshold, protocol type, etc., without requiring on-site manual operation. When the power grid environment changes or the ripple control protocol needs to be changed, the configuration can be updated via remote commands, significantly reducing the workload of on-site maintenance and improving the system's flexibility and maintainability. Attached Figure Description

[0045] Figure 1 The present invention provides a flowchart of a voltage ripple control method for an electricity meter;

[0046] Figure 2 A schematic diagram of the structure of an energy meter applying a voltage ripple control method is provided by the present invention.

[0047] Figure 3 This invention provides a schematic diagram of the working process of a voltage ripple control method for an electricity meter.

[0048] Figure 4 This is a schematic diagram of the data frame structure in one embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the Decabit protocol in one embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram of the Telenerg protocol in one embodiment of the present invention. Detailed Implementation

[0051] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Example 1

[0053] like Figure 1 and Figure 3 As shown, this invention provides a voltage ripple control method for electricity meters, applied to electricity meters including analog-to-digital converters and microprocessors, comprising the following steps:

[0054] S1: Sample the grid voltage to obtain a digital voltage signal containing ripple signals;

[0055] S2: Perform digital filtering on the voltage digital signal to extract the ripple signal within a specific frequency range;

[0056] S3: Perform signal feature calculation on the extracted ripple signal and convert the ripple signal into a digital level signal sequence;

[0057] S4: Parse the digital level signal sequence according to the preset ripple control protocol and output control commands. Specifically, such as... Figure 4 As shown, the energy meter uses an HCT5821B chip to convert the input voltage signal into a discrete signal via an ADC. It reads the ADC data output through an SPI interface, processes the read data according to the data frame structure, and repeats the reading process to obtain continuous discrete signal values. The discrete voltage signal is then input to a microprocessor for further processing, completing the entire process from signal acquisition to control execution. Figure 4 Specifically, this represents the frame structure of the ADC data output. The first byte is all 0s, indicating the start. The next three bytes are the ADCA value, with the first two bytes being data and the last byte being 0. The next three bytes are the ADCB value, with the first two bytes being data and the last byte being 0. ADCA and ADCB correspond to voltage and current data, respectively. The last byte is the checksum, which is the sum of the six bytes of ADCA and ADCB plus the value of 0x5A. By integrating the ripple control signal reception and decoding function, the energy meter can directly control the operation of subsequent loads without the need to deploy a dedicated ripple receiver, reducing deployment and maintenance costs.

[0058] In one specific embodiment of this example, digital filtering of the voltage digital signal includes: filtering the voltage digital signal using a bandpass filter with a passband frequency range of 100Hz to 1500Hz; and adjusting the amplitude of the filtered signal according to a preset scaling factor. The ripple signal injected by the power company typically has a frequency range of 100Hz to 1400Hz, and the bandpass filter is set to a passband range of 100Hz to 1500Hz, which can cover all commonly used ripple frequencies. The filtered signal needs to be scaled by multiplying by a specific scaling factor, which is calculated along with the filter parameters. Bandpass filtering separates the ripple signal of a specific frequency from the voltage signal containing the fundamental frequency and various harmonics, providing an accurate ripple waveform for subsequent signal determination.

[0059] In one specific embodiment of this example, the bandpass filter is an IIR bandpass filter, which filters the voltage digital signal through a cascaded approach. The IIR bandpass filter is implemented based on the CMSIS-DSP library, and the required filter parameters are calculated using the fdatool tool in MATLAB to obtain a filter for a specific ripple frequency. Cascaded filtering refers to using multiple filters in series to progressively improve the filtering effect. Compared to analog filters, IIR filters are not affected by temperature and component aging, and their parameters are programmable, flexibly supporting various frequency switching requirements. Currently, it supports signal filtering at multiple frequency points between 175Hz and 1500Hz.

[0060] In one specific embodiment of this example, the signal feature calculation of the extracted ripple signal includes: calculating the root mean square (RMS) value of the extracted ripple signal within a preset time window; comparing the RMS value with a preset threshold, determining a high level when the RMS value is higher than the preset threshold, and a low level when the RMS value is lower than or equal to the preset threshold; repeating the above calculation and comparison at a sampling period of 10ms to 50ms to generate a digital level signal sequence. The filtered ripple signal is still a series of discrete data, and its RMS value needs to be calculated to obtain the effective value of the ripple signal. The effective value is compared with a set judgment threshold; if it is higher than the threshold, it is determined to be a high level; otherwise, it is a low level. One signal point is acquired in each sampling period, and continuous sampling forms a high-low level sequence. In a specific implementation, the sampling period is set to 20ms, that is, one signal point is acquired every 20ms. Through RMS value calculation and threshold comparison, the analog ripple signal is converted into a high-low level sequence that is easy to digitally process.

[0061] In one specific embodiment of this example, the preset threshold is 0.5% to 5% of the effective voltage value. The amplitude of the ripple signal is typically 1% to 5% of the grid voltage. Setting the judgment threshold to 1% of the effective voltage value can effectively identify the presence of the ripple signal. A threshold value that is too low will lead to false triggering, while a threshold value that is too high will lead to missed detection. The range of 0.5% to 5% can accommodate the ripple signal intensity under different grid environments.

[0062] In one specific embodiment of this example, parsing a digital level signal sequence according to a preset ripple control protocol includes: detecting a start identifier signal in the digital level signal sequence; identifying data segments following the start identifier signal; converting the level duration in the data segments into bit values ​​according to preset protocol rules; and combining the bit values ​​into a control command. The ripple control protocol represents control commands through specific high and low level combinations. The start identifier signal is used to mark the beginning of a command. After identifying the start identifier, subsequent data segments are parsed according to the timing rules specified in the protocol. Different durations of high and low levels correspond to different bit values; combining the parsed bit values ​​in sequence yields a complete control command. By repeatedly executing the above steps, continuous ripple high and low level signals can be obtained. Control commands are then parsed according to the protocol, and the energy meter performs corresponding actions based on the command content agreed upon in the protocol.

[0063] In one specific implementation of this embodiment, such as Figures 5-6 As shown, the preset protocol rules support at least one of the Decabit and Telenerg protocols. Different protocols define the correspondence between the level duration and the bit value through corresponding preset time parameters. In the Decabit protocol, a 600ms high level indicates the start of a control command, and subsequent signals every 600ms represent one bit. A 600ms high level represents bit 1, and a 600ms low level represents bit 0. A command is 10 bits long, and a 600ms low level indicates the end of the command. In the Telenerg protocol, a 1650ms high level and a 600ms low level indicate the start of a control command, and subsequent signals every 1000ms represent one bit. The first 400ms are high, followed by a 600ms low level to represent bit 1, and a 1000ms low level to represent bit 0. By supporting multiple protocols, the energy meter can be adapted to the ripple control standards used by different power companies.

[0064] In one specific embodiment of this example, before executing step 1, the method further includes: receiving a remote configuration command, and adjusting the filtering frequency of the digital filtering process, the threshold value for signal feature calculation, or the protocol type for protocol parsing according to the remote configuration command. The electricity meter itself supports remote communication and can remotely adjust the ripple receiving configuration as needed. The remote configuration content includes switching the ripple control function, changing the receiving frequency, changing the ripple protocol, adjusting the signal strength threshold, etc. After receiving the remote configuration command, the microprocessor updates the corresponding parameter settings, and subsequent ripple detection is performed according to the new configuration. The remote configuration function allows the electricity meter to flexibly adapt to different application scenarios, and parameter adjustments can be completed without on-site operation, improving the maintainability of the system.

[0065] Example 2

[0066] like Figure 2As shown, an energy meter implementing the above method according to the present invention includes an analog-to-digital converter and a microprocessor. The microprocessor includes: a digital filtering module, the input of which is connected to the voltage sampling output of the analog-to-digital converter; a signal determination module, connected to the output of the digital filtering module; a protocol parsing module, connected to the output of the signal determination module; and a control execution module, connected to the output of the protocol parsing module. The digital filtering module implements bandpass filtering to extract ripple signals from the voltage sampling data. The signal determination module calculates the root mean square value of the ripple signal and compares it with a threshold to generate a high-low level sequence. The protocol parsing module parses the high-low level sequence according to preset protocol rules and identifies control commands. The control execution module executes corresponding actions according to the control commands, such as opening and closing a relay. By integrating the above functional modules into the energy meter microprocessor, ripple control and energy metering are integrated, eliminating the need for a dedicated ripple receiver.

[0067] In one specific embodiment of this example, the microprocessor further includes: a configuration management module, connected to a remote communication interface, used to receive remote configuration commands and adjust the filtering parameters of the digital filtering module, the threshold value of the signal determination module, or the protocol type of the protocol parsing module; and an energy calculation module, used to calculate energy consumption based on the sampling data from the analog-to-digital converter. The configuration management module receives configuration commands through the remote communication interface, parses the command content, and modifies the parameters of the corresponding modules. The energy calculation module implements the basic metering function of the energy meter, calculating energy consumption based on voltage and current sampling data. The configuration management module and the energy calculation module are integrated with the ripple control-related modules in the same microprocessor, realizing the fusion of metering and control functions, improving equipment integration and resource utilization.

[0068] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A voltage ripple control method for an electricity meter, characterized in that: Includes the following steps: S1: Sample the grid voltage to obtain a digital voltage signal containing ripple signals; S2: Perform digital filtering on the voltage digital signal to extract the ripple signal within a specific frequency range; S3: Perform signal feature calculation on the extracted ripple signal and convert the ripple signal into a digital level signal sequence; S4: Parse the digital level signal sequence according to the preset ripple control protocol and output control commands. The digital filtering process for the voltage digital signal in step S2 includes: S21: The voltage digital signal is filtered by a bandpass filter, wherein the passband frequency range of the bandpass filter is 100Hz to 1500Hz; S22: Adjust the amplitude of the filtered signal according to a preset proportional coefficient; The bandpass filter is an IIR bandpass filter, which filters the voltage digital signal through cascading. The signal feature calculation for the extracted ripple signal in step S3 includes: S31; Calculate the root mean square value of the extracted ripple signal within a preset time window; S32: Compare the root mean square value with a preset threshold. When the root mean square value is higher than the preset threshold, it is determined to be a high level. When the root mean square value is lower than or equal to the preset threshold, it is determined to be a low level. S33: Repeat the above calculation and comparison with a sampling period of 10ms to 50ms to generate a digital level signal sequence; Before executing S1, the following also applies: The system receives remote configuration commands and adjusts the filtering frequency of digital filtering, the threshold value of signal characteristic calculation, or the protocol type of protocol parsing according to the remote configuration commands. By integrating the ripple control signal receiving and decoding function into the microprocessor of the energy meter, the system uses the existing analog-to-digital converter and microprocessor resources of the energy meter to complete the extraction and parsing of the ripple signal, and the energy meter directly controls the operation of subsequent loads.

2. The voltage ripple control method for an electricity meter according to claim 1, characterized in that: The preset threshold is 0.5% to 5% of the effective voltage value.

3. The voltage ripple control method for an electricity meter according to claim 1, characterized in that: The step S4, which involves parsing the digital level signal sequence according to a preset ripple control protocol, includes: S41: Detect the start marker signal in the digital level signal sequence; S42: Identify the data segment following the start identifier signal; S43: Convert the level duration in the data segment into bit values ​​according to the preset protocol rules; S44: Combine bit values ​​into control commands.

4. A voltage ripple control method for an electricity meter according to claim 3, characterized in that: The preset protocol rules support at least one of Decabit and Telenerg protocols. Different protocols define the correspondence between the level duration and the bit value through corresponding preset time parameters.

5. An energy meter implementing the method of any one of claims 1 to 4, comprising an analog-to-digital converter and a microprocessor, characterized in that, The microprocessor includes: A digital filtering module, the input of which is connected to the output of an analog-to-digital converter, is used to perform digital filtering on a voltage digital signal to extract ripple signals within a specific frequency range. A signal determination module, the input of which is connected to the output of the digital filtering module, is used to perform signal feature calculation on the extracted ripple signal and convert it into a digital level signal sequence; The protocol parsing module has its input connected to the output of the signal determination module and is used to parse the digital level signal sequence according to the preset ripple control protocol and output control commands. The control execution module has its input connected to the output of the protocol parsing module and is used to receive control commands and control the load switch status.

6. The electricity meter according to claim 5, characterized in that, The microprocessor also includes: The configuration management module is connected to a remote communication interface and is used to receive remote configuration commands and adjust the filtering parameters of the digital filtering module, the threshold value of the signal determination module, or the protocol type of the protocol parsing module. An energy calculation module, the input of which is connected to the output of an analog-to-digital converter, is used to calculate the energy consumption based on the sampling data of the analog-to-digital converter.

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