Multi-harmonic combination and accurate output electric energy meter calibrating device and method

Abstract

The invention discloses a multi-harmonic combination and accurate output electric energy meter calibrating device and method, and relates to the technical field of electric energy meter detection. Comprising a harmonic generation module used for generating a harmonic signal; the phase control module is used for adjusting the phase of the generated harmonic signal to obtain an adjusted harmonic signal; the power amplification module is used for amplifying the adjusted harmonic signal to obtain an amplified harmonic signal; the signal monitoring and feedback module is used for monitoring parameters of the amplified harmonic signals in real time and feeding back the monitored parameters; and the upper computer control module is used for receiving the input verification parameters and controlling the harmonic generation module, the phase control module and the power amplification module according to the verification parameters and the feedback parameters. Through the advanced harmonic generation circuit and the accurate phase control module, high accuracy of harmonic content and harmonic phase output is realized.

Description

Technical Field

[0001] This invention relates to the field of electricity meter testing technology, and more specifically to an electricity meter calibration device and method with multi-harmonic combination and accurate output. Background Technology

[0002] With the rapid development of new energy power generation technologies, distributed power sources such as wind power and photovoltaics are being connected to the power grid on a large scale. In addition, the widespread application of nonlinear loads such as electric vehicle charging piles, variable frequency air conditioners, and industrial rectifier equipment has led to increasingly complex harmonic components in the power grid and a more severe harmonic pollution problem. These harmonics not only cause distortion of the voltage and current waveforms of the power grid, but also pose a serious threat to the safe and stable operation of power equipment, with the metering accuracy of electricity meters being particularly affected.

[0003] Traditional electricity meter designs are primarily geared towards ideal sinusoidal power grid environments, and their metering algorithms and hardware structures are ill-suited to complex harmonic environments. In power grids containing multiple harmonics, electricity meters may exhibit measurement deviations. These deviations can range from minor inaccuracies leading to economic disputes between power suppliers and consumers to severe data distortion, impacting fair electricity market transactions and the economic operation of the power grid. Therefore, accurate testing of electricity meter performance under complex harmonic environments is crucial for ensuring fair and impartial electricity metering.

[0004] However, current electricity meter calibration devices on the market have many limitations. On the one hand, most devices can only generate a limited number of harmonics, usually limited to harmonics of the 3rd to 21st order, which cannot cover the wide range of harmonics of the 2nd to 50th orders that may occur in the actual power grid, making it difficult to simulate the real power grid harmonic environment. On the other hand, in terms of harmonic superposition capability, most existing devices can only superimpose harmonics of the 10th to 20th order, and the total harmonic content is usually limited to less than 100%, which is far from meeting the calibration requirements under complex harmonic scenarios and cannot effectively test the metering characteristics of electricity meters in high harmonic content environments.

[0005] More importantly, existing devices have significant shortcomings in terms of the accuracy of harmonic content and phase output. In harmonic content control, the error often exceeds 5%, making it difficult to accurately simulate power grid environments with different harmonic content ratios. In phase control, the phase deviation is typically greater than 1°, failing to accurately reproduce the phase relationship between different harmonics in a real power grid. This results in the inability to accurately detect metering errors in complex harmonic environments, leading to a large number of potentially defective meters entering the market and posing a potential risk to the economic operation of the power system.

[0006] Furthermore, existing calibration devices have a slow response speed, requiring a long stabilization time when switching between different harmonic combinations or adjusting harmonic parameters, thus reducing calibration efficiency. At the same time, their user interface is complex and lacks automation, requiring operators to possess high levels of professional skills, which hinders large-scale application.

[0007] Therefore, proposing a testing device and method for electricity meters with multi-harmonic combination and accurate output to solve the difficulties existing in the prior art is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of this, the present invention provides a device and method for testing electricity meters with multiple harmonic combinations and accurate output, so as to solve the problem that the existing electricity meter testing devices cannot flexibly generate multiple harmonics and the harmonic output accuracy is low, and can provide a reliable means for testing the performance of electricity meters in complex harmonic environments.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A multi-harmonic combination and precise output energy meter calibration device includes a harmonic generation module, a phase control module, a power amplification module, a signal monitoring and feedback module, and a host computer control module. The first output terminal of the host computer control module is sequentially connected to the first input terminal of the harmonic generation module, the first input terminal of the phase control module, the first input terminal of the power amplification module, and the input terminal of the signal monitoring and feedback module. The second output terminal of the host computer control module is connected to the second input terminal of the phase control module. The third output terminal of the host computer control module is connected to the second input terminal of the power amplification module. The first output terminal of the harmonic generation module is connected to the first input terminal of the host computer control module. The first output terminal of the phase control module is connected to the second input terminal of the host computer control module. The first output terminal of the power amplification module is connected to the third input terminal of the host computer control module. The output terminal of the signal monitoring and feedback module is connected to the fourth input terminal of the host computer control module.

[0011] Harmonic generation module, used to generate harmonic signals;

[0012] The phase control module is used to adjust the phase of the generated harmonic signal to obtain the adjusted harmonic signal.

[0013] The power amplifier module is used to amplify the regulated harmonic signal to obtain the amplified harmonic signal;

[0014] The signal monitoring and feedback module is used to monitor the parameters of the amplified harmonic signal in real time and feed back the monitored parameters.

[0015] The host computer control module is used to receive the input verification parameters and control the harmonic generation module, phase control module, and power amplification module based on the verification parameters and feedback parameters.

[0016] Optionally, the harmonic generation module employs a harmonic generator based on direct digital synthesis technology. The harmonic generator includes a multi-channel parallel direct digital synthesis structure, with each channel independently generating a harmonic signal. The outputs of multiple channels are superimposed through an adder.

[0017] Optionally, the harmonic generator uses a temperature-controlled crystal oscillator as the reference clock source, with the frequency stability of the temperature-controlled crystal oscillator on the order of ±10⁻¹¹.

[0018] Optionally, the phase control module includes a digital signal processing chip, a phase-locked loop circuit, and a real-time phase monitoring and calibration unit;

[0019] The digital signal processing chip is used to calculate the phase offset based on the set phase value and to adjust the initial phase of the phase accumulator during the generation of harmonic signals;

[0020] A phase-locked loop circuit is used to synchronize and lock the phase of each harmonic signal with a reference phase.

[0021] The real-time phase monitoring and calibration unit is used to measure the phase of the output harmonic signal in real time. When the deviation between the actual phase and the set phase exceeds the allowable range, the phase of the harmonic signal is corrected.

[0022] Optionally, the digital signal processing chip is a TMS320F28335, the phase measurement interval of the real-time phase monitoring and calibration unit is 100ms, and the allowable phase deviation range is ±0.1°.

[0023] Optionally, the parameters monitored by the signal monitoring and feedback module include harmonic content, phase, and amplitude.

[0024] Optionally, the host computer control module receives the input verification parameters through the human-machine interface. The verification parameters include harmonic order, harmonic content, and phase.

[0025] A method for verifying an energy meter with multi-harmonic combination and accurate output, comprising the following steps, using an energy meter verification device with multi-harmonic combination and accurate output that performs any of the above-mentioned functions:

[0026] S1. Receive the input verification parameters through the host computer control module;

[0027] S2. The host computer control module sends the calibration parameters to the harmonic generation module and the phase control module.

[0028] S3. The harmonic generation module generates harmonic signals based on the verification parameters.

[0029] S4. The phase control module controls the phase of the generated harmonic signal.

[0030] S5, the power amplifier module amplifies the phase-controlled harmonic signal and outputs it to the energy meter for verification;

[0031] S6, the signal monitoring and feedback module monitors the parameters of the output signal in real time and feeds back the monitored parameters to the host computer control module;

[0032] S7. The host computer control module adjusts the harmonic generation module, phase control module, and power amplification module based on the feedback parameters.

[0033] Optionally, the harmonic generation module in S3 generates corresponding harmonic signals of the 2nd to 50th order according to the verification parameters, and superimposes any 36th harmonic signal to make the total harmonic content of the superimposed signal ≤250%.

[0034] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a device and method for calibrating energy meters with multi-harmonic combination and accurate output, the beneficial effects of which are:

[0035] 1) This invention can support the generation of 2nd to 50th harmonics, and can arbitrarily superimpose 36th harmonics. The total harmonic content can be effectively controlled within the range of ≤250%, which greatly enriches the harmonic environment that can be simulated and can more realistically reflect the complex harmonic situation in the actual power grid.

[0036] 2) Through advanced harmonic generation circuits and precise phase control modules, high accuracy of harmonic content and harmonic phase output is achieved, providing a reliable means for performance testing of electricity meters in complex harmonic environments, which helps to improve the metering accuracy and reliability of electricity meters and ensure the safe and stable operation of the power system.

[0037] 3) The overall architecture of the device is reasonably designed, with each module working together and easy to operate. Various verification parameters can be easily set through the host computer control module, and the signal monitoring and feedback module can monitor the output signal in real time, ensuring the stability and accuracy of the device operation. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0039] Figure 1The structural diagram of the energy meter calibration device with multi-harmonic combination and accurate output provided by the present invention is shown.

[0040] Figure 2 The flowchart illustrates the method for calibrating an energy meter with multi-harmonic combination and accurate output provided by this invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0042] See Figure 1 As shown, the energy meter calibration device with multi-harmonic combination and accurate output includes a harmonic generation module, a phase control module, a power amplification module, a signal monitoring and feedback module, and a host computer control module. The first output terminal of the host computer control module is sequentially connected to the first input terminal of the harmonic generation module, the first input terminal of the phase control module, the first input terminal of the power amplification module, and the input terminal of the signal monitoring and feedback module. The second output terminal of the host computer control module is connected to the second input terminal of the phase control module. The third output terminal of the host computer control module is connected to the second input terminal of the power amplification module. The first output terminal of the harmonic generation module is connected to the first input terminal of the host computer control module. The first output terminal of the phase control module is connected to the second input terminal of the host computer control module. The first output terminal of the power amplification module is connected to the third input terminal of the host computer control module. The output terminal of the signal monitoring and feedback module is connected to the fourth input terminal of the host computer control module.

[0043] Harmonic generation module, used to generate harmonic signals;

[0044] The phase control module is used to adjust the phase of the generated harmonic signal to obtain the adjusted harmonic signal.

[0045] The power amplifier module is used to amplify the regulated harmonic signal to obtain the amplified harmonic signal;

[0046] The signal monitoring and feedback module is used to monitor the parameters of the amplified harmonic signal in real time and feed back the monitored parameters.

[0047] The host computer control module is used to receive the input verification parameters and control the harmonic generation module, phase control module, and power amplification module based on the verification parameters and feedback parameters.

[0048] The specific workflow is as follows: First, the operator sets the required harmonic parameters, including harmonic order, harmonic content, and phase, in the host computer control module interface. The host computer control module sends these parameters to the harmonic generation module and the phase control module. The harmonic generation module generates the corresponding harmonic signal using direct digital synthesis technology based on the set harmonic order. The phase control module precisely adjusts the phase of the harmonic signal according to the set phase value. The generated harmonic signal is amplified by the power amplifier module and then output to the energy meter for verification. During the verification process, the signal monitoring and feedback module monitors the parameters of the output signal in real time and feeds these parameters back to the host computer. Based on the feedback information, the host computer monitors and adjusts the operating status of the device in real time to ensure the accuracy and stability of the output signal. If the parameters of the output signal are found to be inconsistent with the set requirements, the host computer control module will automatically issue instructions to adjust the harmonic generation module, phase control module, or power amplifier module accordingly to ensure the smooth progress of the verification work.

[0049] Furthermore, the harmonic generation module adopts a harmonic generator based on direct digital synthesis technology. The harmonic generator includes a multi-channel parallel direct digital synthesis structure, with each channel independently generating a harmonic signal, and the outputs of multiple channels are superimposed by an adder.

[0050] Specifically, this invention employs direct digital synthesis (DDS) technology to generate harmonic signals. DDS synthesizes waveforms digitally, offering advantages such as fast frequency conversion speed, high frequency resolution, and good phase continuity. Its working principle is as follows: A phase accumulator is used to increment the phase value according to a set frequency control word within each clock cycle. The output of the phase accumulator serves as an address, retrieving the corresponding sine amplitude data from a sine lookup table. This data is converted into an analog signal by a digital-to-analog converter (DAC), and then smoothed by a low-pass filter to obtain the desired sine wave signal. For example, to generate the 5th harmonic, simply set the frequency control word to five times the fundamental frequency control word, and the 5th harmonic signal will be obtained at the output.

[0051] To achieve the simultaneous generation and superposition of multiple harmonics, this device employs a multi-channel parallel direct digital synthesis (DDS) structure. Each channel independently generates a harmonic signal, and the outputs of multiple channels are superimposed through an adder. This allows for flexible combination of harmonics of different orders and concentrations. For example, to generate a composite signal containing 3rd, 7th, and 11th harmonics, these three harmonics can be generated separately through three independent DDS channels, and then added together in the adder to obtain the final composite harmonic signal. Each channel uses a high-performance DDS chip, such as the AD9854, which features a high-speed clock frequency and a high-resolution phase accumulator, meeting the requirements for high-precision harmonic generation.

[0052] Furthermore, the harmonic generator uses a temperature-controlled crystal oscillator as the reference clock source, and the frequency stability of the temperature-controlled crystal oscillator is on the order of ±10⁻¹¹.

[0053] Specifically, the accuracy of the harmonic generation circuit depends on a stable and high-precision reference clock. This invention uses a oven-controlled crystal oscillator as the reference clock source. Oven-controlled crystal oscillators have extremely low frequency drift and stability, providing a stable clock signal for the direct digital synthesis chip, thereby ensuring the frequency accuracy of the harmonic signal. For example, the selected oven-controlled crystal oscillator can achieve a frequency stability on the order of ±10⁻¹¹, ensuring that the frequency deviation of the harmonic signal remains within a very small range during long-term operation, meeting the stringent requirements for harmonic frequency accuracy in energy meter calibration.

[0054] Furthermore, the phase control module includes a digital signal processing chip, a phase-locked loop circuit, and a real-time phase monitoring and calibration unit;

[0055] The digital signal processing chip is used to calculate the phase offset based on the set phase value and to adjust the initial phase of the phase accumulator during the generation of harmonic signals;

[0056] Specifically, digital signal processing technology is used to precisely control the phase of the harmonic signal. First, the corresponding phase offset is calculated based on the set phase value. Then, during the digital signal processing to generate the harmonic signal, the initial phase of the phase accumulator is adjusted. For example, if the phase of a certain harmonic is to be lagging by 30°, the corresponding phase offset is calculated by the algorithm and added during the initialization of the phase accumulator, so that the generated harmonic signal has a 30° phase lag at output.

[0057] A phase-locked loop circuit is used to synchronize and lock the phase of each harmonic signal with a reference phase.

[0058] Specifically, to ensure the accuracy of the phase relationship between different harmonics, this device employs phase synchronization and locking technology. A phase-locked loop (PLL) circuit synchronizes the phase of each harmonic signal with a common reference phase. The PLL circuit automatically tracks changes in the reference phase and adjusts the phase of the harmonic signals to maintain a fixed phase difference with the reference phase. For example, in a composite signal containing multiple harmonics, the PLL circuit ensures that the phase difference between the 3rd harmonic and the fundamental wave remains at a set value, such as 90°, and the phase difference between the 7th harmonic and the fundamental wave remains at 180°, etc. This accurately simulates the complex harmonic phase relationships in a real power grid, providing a more realistic testing environment for the calibration of electricity meters.

[0059] The real-time phase monitoring and calibration unit is used to measure the phase of the output harmonic signal in real time. When the deviation between the actual phase and the set phase exceeds the allowable range, the phase of the harmonic signal is corrected.

[0060] Specifically, to further improve the accuracy of the phase output, this device is equipped with a real-time phase monitoring and calibration system. A high-precision phase detection circuit measures the phase of the output harmonic signal in real time and compares it with a set value. If a phase deviation exists, the system will automatically initiate a calibration procedure, correcting the phase of the harmonic signal by adjusting the phase control parameters in the digital signal processing. For example, at regular time intervals (e.g., 100ms), the phase detection circuit measures the phase of the output harmonic signal. If the actual phase of a harmonic is found to differ from the set phase by more than the allowable error range (e.g., ±0.1°), the system immediately performs calibration to ensure that the accuracy of the phase output always meets the requirements.

[0061] Furthermore, the digital signal processing chip is model TMS320F28335, the phase measurement interval of the real-time phase monitoring and calibration unit is 100ms, and the allowable phase deviation range is ±0.1°.

[0062] Specifically, the digital signal processing chip selected is Texas Instruments' TMS320F28335, which has high-speed data processing capabilities and abundant on-chip resources, enabling it to execute phase control algorithms quickly and accurately.

[0063] Furthermore, the parameters monitored by the signal monitoring and feedback module include harmonic content, phase, and amplitude.

[0064] Furthermore, the host computer control module receives the input verification parameters through the human-machine interface. The verification parameters include harmonic order, harmonic content, and phase.

[0065] and Figure 1 Corresponding to the aforementioned device, this invention also proposes a method for calibrating energy meters with multi-harmonic combination and accurate output, used for... Figure 1 For a detailed implementation of the device, please refer to the flowchart. Figure 2 As shown, it includes the following steps:

[0066] S1. Receive the input verification parameters through the host computer control module;

[0067] S2. The host computer control module sends the calibration parameters to the harmonic generation module and the phase control module.

[0068] S3. The harmonic generation module generates harmonic signals based on the verification parameters.

[0069] S4. The phase control module controls the phase of the generated harmonic signal.

[0070] S5, the power amplifier module amplifies the phase-controlled harmonic signal and outputs it to the energy meter for verification;

[0071] S6, the signal monitoring and feedback module monitors the parameters of the output signal in real time and feeds back the monitored parameters to the host computer control module;

[0072] S7. The host computer control module adjusts the harmonic generation module, phase control module, and power amplification module based on the feedback parameters.

[0073] Furthermore, the harmonic generation module in S3 generates corresponding harmonic signals of the 2nd to 50th order according to the verification parameters, and superimposes any 36th harmonic signal to make the total harmonic content of the superimposed signal ≤250%.

[0074] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0075] The system disclosed in the embodiments is described in a relatively simple manner because it corresponds to the method disclosed in the embodiments. For relevant details, please refer to the method section.

[0076] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power meter calibration device with multi-harmonic combination and precise output, characterized in that, It includes a harmonic generation module, a phase control module, a power amplification module, a signal monitoring and feedback module, and a host computer control module. The first output terminal of the host computer control module is sequentially connected to the first input terminal of the harmonic generation module, the first input terminal of the phase control module, the first input terminal of the power amplification module, and the input terminal of the signal monitoring and feedback module. The second output terminal of the host computer control module is connected to the second input terminal of the phase control module. The third output terminal of the host computer control module is connected to the second input terminal of the power amplification module. The first output terminal of the harmonic generation module is connected to the first input terminal of the host computer control module. The first output terminal of the phase control module is connected to the second input terminal of the host computer control module. The first output terminal of the power amplification module is connected to the third input terminal of the host computer control module. The output terminal of the signal monitoring and feedback module is connected to the fourth input terminal of the host computer control module. Harmonic generation module, used to generate harmonic signals; The phase control module is used to adjust the phase of the generated harmonic signal to obtain the adjusted harmonic signal. The power amplifier module is used to amplify the regulated harmonic signal to obtain the amplified harmonic signal; The signal monitoring and feedback module is used to monitor the parameters of the amplified harmonic signal in real time and feed back the monitored parameters. The host computer control module is used to receive the input verification parameters and control the harmonic generation module, phase control module, and power amplification module based on the verification parameters and feedback parameters.

2. The energy meter calibration device with multi-harmonic combination and accurate output according to claim 1, characterized in that, The harmonic generation module uses a harmonic generator based on direct digital synthesis technology. The harmonic generator includes a multi-channel parallel direct digital synthesis structure. Each channel independently generates a harmonic signal, and the outputs of multiple channels are superimposed by an adder.

3. The energy meter calibration device with multi-harmonic combination and accurate output according to claim 2, characterized in that, The harmonic generator uses a temperature-controlled crystal oscillator as the reference clock source, and the frequency stability of the temperature-controlled crystal oscillator is on the order of ±10⁻¹¹.

4. The energy meter calibration device with multi-harmonic combination and accurate output according to claim 1, characterized in that, The phase control module includes a digital signal processing chip, a phase-locked loop circuit, and a real-time phase monitoring and calibration unit; The digital signal processing chip is used to calculate the phase offset based on the set phase value and to adjust the initial phase of the phase accumulator during the generation of harmonic signals; A phase-locked loop circuit is used to synchronize and lock the phase of each harmonic signal with a reference phase. The real-time phase monitoring and calibration unit is used to measure the phase of the output harmonic signal in real time. When the deviation between the actual phase and the set phase exceeds the allowable range, the phase of the harmonic signal is corrected.

5. The energy meter calibration device with multi-harmonic combination and accurate output according to claim 4, characterized in that, The digital signal processing chip is model TMS320F28335. The phase measurement interval of the real-time phase monitoring and calibration unit is 100ms, and the allowable phase deviation range is ±0.1°.

6. The energy meter calibration device with multi-harmonic combination and accurate output according to claim 1, characterized in that, The parameters monitored by the signal monitoring and feedback module include harmonic content, phase, and amplitude.

7. The energy meter calibration device with multi-harmonic combination and accurate output according to claim 1, characterized in that, The host computer control module receives the input verification parameters through the human-machine interface. The verification parameters include harmonic order, harmonic content and phase.

8. A method for calibrating an energy meter with multiple harmonic combinations and accurate output, characterized in that, The energy meter calibration device with multi-harmonic combination and accurate output as described in any one of claims 1-7 includes the following steps: S1. Receive the input verification parameters through the host computer control module; S2. The host computer control module sends the calibration parameters to the harmonic generation module and the phase control module. S3. The harmonic generation module generates harmonic signals based on the verification parameters. S4. The phase control module controls the phase of the generated harmonic signal. S5, the power amplifier module amplifies the phase-controlled harmonic signal and outputs it to the energy meter for verification; S6, the signal monitoring and feedback module monitors the parameters of the output signal in real time and feeds back the monitored parameters to the host computer control module; S7. The host computer control module adjusts the harmonic generation module, phase control module, and power amplification module based on the feedback parameters.

9. The method for calibrating an energy meter with multi-harmonic combination and accurate output according to claim 8, characterized in that, The harmonic generation module in S3 generates corresponding harmonic signals from the 2nd to the 50th order according to the verification parameters, and superimposes any 36th harmonic signal to make the total harmonic content of the superimposed signal ≤250%.

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