CN113866705A - Harmonic correction method and device, electric energy metering equipment and readable storage medium - Google Patents
Harmonic correction method and device, electric energy metering equipment and readable storage medium Download PDFInfo
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Abstract
The invention discloses a harmonic correction method, which comprises the following steps: receiving an input harmonic signal and generating a frequency spectrum monitoring amplitude; acquiring a harmonic correction gain value corresponding to the harmonic signal in a preset harmonic correction gain value sequence table; taking the product of the spectrum monitoring amplitude and the harmonic correction gain value as the spectrum correction amplitude of the harmonic signal; and forming a harmonic spectrum according to the spectrum correction amplitude, and outputting the harmonic spectrum. The invention also discloses a device, electric energy metering equipment and a readable storage medium. By applying the harmonic correction method of the invention to the electric energy metering equipment, the output harmonic spectrum amplitude and the accuracy of the harmonic spectrum can be improved under the condition of continuously keeping the high-precision sampling of the electric energy metering equipment, the problem of serious distortion of the output harmonic spectrum amplitude is avoided, and the realization cost is extremely low.
Description
Technical Field
The invention relates to the field of power electronics, in particular to a harmonic correction method and device, electric energy metering equipment and a readable storage medium.
Background
With the rapid development of power electronic technology, the proportion of nonlinear load in the power grid gradually increases. At present, the harmonic pollution problem caused by nonlinear load in a power grid is increasingly highlighted, the attention of a power management department to harmonic monitoring is also increasingly improved, and the new-generation intelligent electric energy meter of the national power grid and the southern power grid is required to have a harmonic monitoring function. Analog sampling in high-precision electric energy metering equipment generally adopts sigma-delta type electric energy metering equipment with high resolution, high integration and high cost performance, but a digital decimation filter in the analog-to-digital conversion process of the existing sigma-delta type electric energy metering equipment can cause higher harmonic signal amplitude to generate larger distortion, and in addition, in order to obtain high-precision sampling, the digital decimation filter is most widely used in sinc3Topology, for sinc3The topological structure has the advantages that actually monitored harmonic signal frequency spectrum amplitudes with different frequencies have distortion with different degrees, and the accuracy requirement of power harmonic monitoring is exceeded. Therefore, there is a need to improve the harmonic monitoring accuracy of sigma-delta power metering devices.
Disclosure of Invention
The invention provides a harmonic correction method, a harmonic correction device, electric energy metering equipment and a readable storage medium, and aims to solve the technical problem of how to improve the harmonic monitoring accuracy of sigma-delta electric energy metering equipment.
In order to achieve the above object, the present invention provides a harmonic correction method, including the steps of:
receiving an input harmonic signal and generating a frequency spectrum monitoring amplitude;
acquiring a harmonic correction gain value corresponding to the harmonic signal in a preset harmonic correction gain value sequence table;
taking the product of the spectrum monitoring amplitude and the harmonic correction gain value as the spectrum correction amplitude of the harmonic signal;
and forming a harmonic spectrum according to the spectrum correction amplitude, and outputting the harmonic spectrum.
Optionally, the harmonic correction method is applied to a digital decimation filter sinc3(ii) a What is needed isThe step of receiving an input harmonic signal and generating a spectrally monitored amplitude may be preceded by the steps of:
calculating to obtain an oversampling rate according to a preset sampling rate and a preset modulation frequency;
determining a digital decimation filter sinc based on the oversampling ratio3And converting the transfer function into an amplitude-frequency response expression;
calculating all harmonic correction gain values corresponding to the harmonic signals of all frequencies according to the amplitude-frequency response expression to generate a harmonic correction gain value sequence table;
and taking the harmonic correction gain value sequence table as a preset harmonic correction gain value sequence table.
Optionally, the digital decimation filter sinc3The transfer function of (a) is:
H(z)＝[(1-z-N)/(N×(1-z-1))]3，
the amplitude-frequency response expression is as follows:
H(f)＝|sin(Nπf/fMOD)/(N×sin(πf/fMOD))|3，
wherein H (z) is a digital decimation filter sinc3The transfer function of (a); n is an oversampling ratio; z is an argument of the transfer function H (z); h (f) is a digital decimation filter sinc3The amplitude-frequency response of; f. ofMODIs a preset modulation frequency; f is the argument of the amplitude-frequency response H (f).
Optionally, the step of calculating all harmonic correction gain values corresponding to the harmonic signals of all frequencies according to the amplitude-frequency response expression includes:
G(n)＝1/H(nfi)＝|(N×sin(πnfi/fMOD))/sin(Nπnfi/fMOD)|3
wherein f isiIs a preset frequency interval; n is the serial number of the frequency value, and G (n) is the correction gain value corresponding to the frequency value with the serial number of n; h (nf)i) To a frequency of nfiTime-digital decimation filter sinc3The amplitude-frequency response of; n is an oversampling ratio; f. ofMODIs a preset modulation frequency.
Optionally, the step of calculating an oversampling rate according to a preset sampling rate and a preset modulation frequency includes:
and calculating a proportional value of the preset modulation frequency and the preset sampling rate, and taking the proportional value as an oversampling rate.
Optionally, the step of generating a harmonic correction gain value sequence table includes:
and associating and storing the frequency values of the harmonic signals of all the frequencies and all the harmonic correction gain values to a preset table to generate a harmonic correction gain value sequence table.
Optionally, the step of receiving an input harmonic signal and generating a spectrum monitoring amplitude comprises:
receiving an input harmonic analog signal and converting the harmonic analog signal into a harmonic digital signal;
and converting the harmonic digital signal into a frequency spectrum monitoring amplitude.
Further, to achieve the above object, the present invention also provides a harmonic correction apparatus including:
the signal receiving module is used for receiving an input harmonic signal and generating a frequency spectrum monitoring amplitude;
the monitoring and correcting module is used for acquiring a harmonic correction gain value corresponding to the harmonic signal in a preset harmonic correction gain value sequence table; taking the product of the spectrum monitoring amplitude and the harmonic correction gain value as the spectrum correction amplitude of the harmonic signal;
and the frequency spectrum output module is used for forming a harmonic frequency spectrum according to the frequency spectrum correction amplitude and outputting the harmonic frequency spectrum.
Further, to achieve the above object, the present invention also provides an electric energy metering apparatus including a memory, a processor, and a harmonic correction program stored on the memory and executable on the processor, wherein: the harmonic correction program when executed by the processor implements the steps of the harmonic correction method as described above.
Further, to achieve the above object, the present invention also provides a readable storage medium having stored thereon a harmonic correction program, which when executed by a processor, implements the steps of the harmonic correction method as described above.
The harmonic correction method comprises the steps of receiving input harmonic signals, generating all frequency spectrum monitoring amplitudes, obtaining harmonic correction gain values corresponding to the harmonic signals in a preset harmonic correction gain value sequence table, taking the product of the frequency spectrum monitoring amplitudes and the harmonic correction gain values as all frequency spectrum correction amplitudes of the harmonic signals, forming harmonic frequency spectrums according to the frequency spectrum correction amplitudes, and outputting the harmonic frequency spectrums. The frequency spectrum monitoring amplitude can be automatically corrected when the sigma-delta type electric energy metering equipment monitors harmonic waves, the problem that the output harmonic frequency spectrum amplitude is seriously distorted is avoided, namely, the harmonic frequency spectrum amplitude and the harmonic frequency spectrum which are more accurate can be output, the precision requirement of the sigma-delta type electric energy metering equipment for monitoring the harmonic waves is met, and the realization cost is extremely low.
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FIG. 1 is a schematic flow chart of a harmonic correction method according to a first embodiment of the present invention;
FIG. 2 is a schematic flow chart of a harmonic correction method according to a second embodiment of the present invention;
FIG. 3 is a schematic diagram of a harmonic correction apparatus according to the harmonic correction method of the present invention;
FIG. 4 is a block diagram of an analog-to-digital converter in an electric energy metering device related to the harmonic correction method of the present invention;
FIG. 5 is a graph of the spectrum amplitude error output by the electric energy metering device before correction according to the harmonic correction method of the present invention;
FIG. 6 is a diagram illustrating an error of the corrected spectrum amplitude output by the electric energy metering device according to the harmonic correction method of the present invention.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1, fig. 1 is a schematic flow chart of a first embodiment of the harmonic correction method of the present invention, and fig. 4 is a schematic flow chart of an analog-to-digital converter in an electric energy metering device according to the harmonic correction method of the present invention, the electric energy metering device may be a sigma-delta type electric energy metering device, the sigma-delta type electric energy metering device includes the sigma-delta analog-to-digital converter, in this embodiment, a description is given by taking a sigma-delta type electric energy metering device as an example, but not limited to the sigma-delta type electric energy metering device; the harmonic correction method includes:
step S10, receiving the input harmonic signal and generating a frequency spectrum monitoring amplitude;
the present embodiment can be applied to sigma-delta analog-to-digital converters of any brand or specification, as shown in fig. 4, the sigma-delta analog-to-digital converter is composed of two parts, the first part is an analog sigma-delta modulator, the second part is a digital decimation filter, the sigma-delta modulator samples the input analog signal at an extremely high sampling frequency, and performs low-bit quantization on the difference between the two samples, so as to obtain a digital signal expressed by a low-bit code, i.e., a sigma-delta code; and then the sigma-delta code is sent to a digital decimation filter of a second part for decimation filtering, so that a high-resolution linear pulse code modulation digital signal is obtained. Harmonics are electric quantities contained in a current at frequencies that are integral multiples of the fundamental wave, and are generally called harmonics, while the fundamental wave is a component having the same frequency as the power frequency (50 Hz).
The sigma-delta type electric energy metering equipment also needs to receive and monitor harmonic signals in the power grid in the working process of measuring and recording the generated energy, the power supply quantity, the line loss electric quantity, the power consumption of users and the like. In particular, the sigma-delta modulator follows a modulation frequency f set in advanceMODSampling the analog signal of the harmonic wave, quantizing the analog signal into a digital signal of the harmonic wave, and filtering the digital signal of the harmonic wave through the extraction of a digital extraction filter, thereby continuously generating the frequency spectrum monitoring amplitude of the harmonic wave signal. The frequency spectrum monitoring amplitude is a harmonic frequency spectrum amplitude monitored by the sigma-delta type electric energy metering equipment without any correction.
Step S20, obtaining a harmonic correction gain value corresponding to the harmonic signal in a preset harmonic correction gain value sequence table;
since the harmonics are all integer multiples of the fundamental wave (50Hz), the harmonics can be divided into harmonics of different orders to be distinguished according to the integer multiples of the fundamental wave, and for example, the harmonics of 100Hz and 500Hz can be divided into 2 nd order harmonics and 10 th order harmonics. The harmonic correction gain value sequence table is pre-stored in a system of the electric energy metering device, wherein data in the table are harmonic correction gain values corresponding to harmonic signals of various frequencies or various wave orders, the harmonic correction gain values are obtained by performing a series of conversion and calculation on the harmonic signals, specifically, an oversampling rate of a sigma-delta analog-to-digital converter is obtained first, a topological structure function of a digital decimation filter is converted to obtain an amplitude-frequency response expression of a harmonic, and finally, the harmonic correction gain value corresponding to the harmonic signal can be obtained through calculation according to the amplitude-frequency response expression, a modulation frequency of a sigma-delta modulator and the oversampling rate, and the frequency or the wave order of the harmonic signal and the corresponding harmonic correction gain value are stored in an associated manner to generate the harmonic correction gain value sequence table. The harmonic correction gain values of which harmonic signals are required can be calculated according to actual needs to generate a harmonic correction gain value sequence table containing the harmonic signals, so that after the harmonic signals are received, the harmonic correction gain values corresponding to the harmonic signals can be searched and obtained in the harmonic correction gain value sequence table. If the harmonic signal received by the sigma-delta modulator does not have a corresponding harmonic correction gain value in the harmonic correction gain value sequence table, the harmonic correction gain value of the harmonic signal can be directly calculated by using the above calculation mode, and then the harmonic correction gain value is used for correcting the frequency spectrum monitoring amplitude of the harmonic signal. In addition, the newly calculated harmonic correction gain value can be added into the original harmonic correction gain value sequence table.
Step S30, taking the product of the spectrum monitoring amplitude and the harmonic correction gain value as the spectrum correction amplitude of the harmonic signal.
The frequency spectrum monitoring amplitude is a dynamically changing numerical value, and is continuously generated by the sigma-delta type electric energy metering equipment according to a certain frequency, so that the frequency spectrum monitoring amplitude can be one numerical value or a plurality of numerical values. For example, the correction gain value corresponding to the harmonic signal acquired in the harmonic correction gain value sequence table at 150Hz is 1.0007, one of the spectrum monitoring amplitudes of the harmonic signal is 60A, 60.042A is obtained by multiplying 60A by 1.0007, and 60.042A is used as one of the spectrum correction amplitudes.
And step S40, forming a harmonic spectrum according to the spectrum correction amplitude, and outputting the harmonic spectrum.
The frequency spectrum monitoring amplitude of the harmonic signal continuously generated by the sigma-delta type electric energy metering equipment according to a certain frequency is converted into the frequency spectrum of the harmonic, and the frequency spectrum monitoring amplitude and the harmonic frequency spectrum of the harmonic signal are continuously output.
The harmonic correction method comprises the steps of receiving an input harmonic signal, generating a frequency spectrum monitoring amplitude, obtaining a harmonic correction gain value corresponding to the harmonic signal in a preset harmonic correction gain value sequence table, taking the product of the frequency spectrum monitoring amplitude and the harmonic correction gain value as a frequency spectrum correction amplitude of the harmonic signal, forming a harmonic frequency spectrum according to the frequency spectrum correction amplitude, and outputting the harmonic frequency spectrum. The frequency spectrum monitoring amplitude can be automatically corrected when the sigma-delta type electric energy metering equipment monitors harmonic waves, the problem that the output harmonic frequency spectrum amplitude is seriously distorted is avoided, namely, the harmonic frequency spectrum amplitude and the harmonic frequency spectrum which are more accurate can be output, the precision requirement of the sigma-delta type electric energy metering equipment for monitoring the harmonic waves is met, and the realization cost is extremely low.
As shown in fig. 2, a second embodiment of the harmonic correction method of the present invention is further proposed based on the first embodiment of the harmonic correction method of the present invention, which is applied to the digital decimation filter sinc in this embodiment3(ii) a Step S10 is preceded by:
step S100, calculating to obtain an oversampling rate according to a preset sampling rate and a preset modulation frequency;
specifically, the ratio of the preset modulation frequency to the preset sampling rate is used as the oversampling rate, wherein both the modulation frequency and the sampling rate can be preset according to the implementation situation.
Step S110, determining a digital decimation filter sinc according to the oversampling rate3And converting the transfer function into an amplitude-frequency response expression；
The embodiment is applied to sinc3Digital decimation filter of structure, sinc3The transfer function of the structure is converted into an expression of the amplitude-frequency response, which is the ratio of the amplitude of the output harmonic signal to the amplitude of the signal at its input.
In particular according to sinc3Transfer function of the structure: h (z) [ (1-z-N)/(N × (1-z-1))]3,
Since the z-transform on the unit circle is the fourier transform of the sequence, let z be ejωWhere ω is 2 π f/fs＝2πf/fMODTo obtain a digital decimation filter sinc3The frequency response expression of (a):
H(ejω)＝[(1-e-jωN)/(N×(1-e-jω))]3
according to the euler formula:
cos(x)＝(ejx+e-jx)/2
sin(x)＝(ejx-e-jx)/2j
or
ejx＝cos(x)+j sin(x)
e-jx＝cos(x)-j sin(x)
Using the above relationship, H (e) is simplifiedjω)＝[(1-e-jωN)/(N×(1-e-jω))]3To obtain
Then, the modulus is taken to obtain the sinc of the digital decimation filter3The amplitude-frequency response expression of (1):
by using
To obtain H (f) ═ sin (N pi f/f)MOD)/(N×sin(πf/fMOD))|3Where H (z) is a digital decimation filter sinc3The transfer function of (a); n is an oversampling ratio; z is an argument of the transfer function H (z); h (f) is a digital decimation filter sinc3The amplitude-frequency response of; f. ofMODIs a preset modulation frequency; f is the argument of the amplitude-frequency response h (f) and is also the frequency of the actual input signal, and ω is the circular frequency, i.e. the digital angular frequency, of the relative discrete system and discrete signal.
Step S120, calculating all harmonic correction gain values corresponding to harmonic signals of all frequencies according to the amplitude-frequency response expression, and generating a harmonic correction gain value sequence table;
specifically, g (n) ═ 1/H (nf)i)＝|(N×sin(πnfi/fMOD))/sin(Nπnfi/fMOD)|3
Wherein f isiThe value of the preset frequency interval is 50 Hz; n is the serial number of the frequency value, and G (n) is the correction gain value corresponding to the frequency value with the serial number of n; h (nf)i) To a frequency of nfiTime-digital decimation filter sinc3The amplitude-frequency response of; n is an oversampling ratio; f. ofMODIs the modulation frequency.
The step of generating a sequence list of harmonic correction gain values comprises: and associating and storing the frequency values of the harmonic signals of all the frequencies and all the harmonic correction gain values to a preset table to generate a harmonic correction gain value sequence table.
The sigma-delta type electric energy metering equipment can store the frequency value of the harmonic of each frequency, such as the frequency value of 100Hz, and the harmonic correction gain value of the harmonic of each frequency obtained by calculation in a well-established table in a system in an associated manner, for example, the harmonic correction gain value of the harmonic of 100Hz is 1.0007, the keywords of 100Hz and 1.0007 can be stored in the table in the system in an associated manner, the frequency value of the harmonic of each frequency and the harmonic correction gain value of the harmonic of each frequency are stored in the table in the system in an associated manner, a harmonic correction gain value sequence table is generated, if the harmonic of a certain frequency is not in the generated harmonic correction gain value sequence table, the harmonic of the certain frequency and the harmonic correction gain value of the harmonic obtained by calculation can be stored in the original harmonic correction gain value sequence table in an associated manner, namely, the harmonic correction gain value sequence table is not invariable, and may be varied according to the actual circumstances. In addition, the harmonics corresponding to the harmonics of each frequency and the harmonic correction gain value of the harmonic may be stored in a table created in the system in an associated manner, for example, the harmonic correction gain value of the harmonic of 200Hz is calculated to be 1.0009, and the keyword 4 corresponding to the harmonic of 200Hz and 1.0009 are stored in the table in the system in an associated manner.
For example, an electric energy metering device including a sigma-delta analog-to-digital converter of the company model ADS131M08 is used, and the preset sampling rate is fsThe modulation frequency of the ADS131M08 sigma-delta analog-to-digital converter is f at 12.8kHzMOD3.2768MHz, thereby setting the oversampling of the ADS131M08 sigma-delta analog-to-digital converter to N-fMOD/fs256. The resulting correction gain sequences at 50Hz frequency intervals in the 50-2500Hz frequency range are expressed in the following array:
G[1:50]＝{1.0001,1.0003,1.0007,1.0012,1.0019,1.0027,1.0037,1.0048,1.0061,1.0076,1.0092,1.0109,1.0128,1.0149,1.0171,1.0195,1.0220,1.0247,1.0276,1.0306,1.0338,1.0372,1.0407,1.0445,1.0483,1.0524,1.0566,1.0611,1.0657,1.0704,1.0754,1.0806,1.0859,1.0915,1.0973,1.1032,1.1094,1.1158,1.1223,1.1291,1.1362,1.1434,1.1509,1.1586,1.1666,1.1748,1.1832,1.1919,1.2008,1.2101}。
the harmonic signals of the corresponding frequencies are corrected by using the correction gain sequence, and the spectrum amplitude errors of the output before and after correction are respectively shown in fig. 5 and fig. 6. It can be easily seen from the graph that before correction, it is monitored that the spectrum amplitude error increases with the increase of the frequency value, the spectrum amplitude error of the 25 th frequency value (i.e. 25 th harmonic, frequency value 1250Hz) reaches-5%, and the spectrum amplitude error of the 50 th frequency value (i.e. 50 th harmonic, frequency value 2500Hz) reaches-17%; after correction, the frequency spectrum amplitude errors from the 1 st frequency to the 50 th frequency (namely, in the frequency range of 50-2500 Hz) are within +/-0.2%, so that the accuracy of the sigma-delta type electric energy metering equipment for harmonic monitoring is effectively improved.
And step S130, taking the harmonic correction gain value sequence table as a preset harmonic correction gain value sequence table.
For example, the harmonic correction gain value sequence table described above may be pre-stored in a system of the electric energy metering device as a preset harmonic correction gain value sequence table.
Further, a third embodiment of the harmonic correction method of the present invention is proposed based on the second embodiment of the harmonic correction method of the present invention, and in this embodiment, the step of receiving an input harmonic signal and generating a spectrum monitoring amplitude includes:
step a, receiving an input harmonic analog signal and converting the harmonic analog signal into a harmonic digital signal;
step b, converting the harmonic digital signal into a frequency spectrum monitoring amplitude
Referring to fig. 4, unlike a general ADC, the sigma-delta type ADC does not perform quantization coding directly according to the size of each sample of sample data, but performs quantization coding according to the difference between a previous magnitude and a subsequent magnitude, i.e., the size of a so-called increment. The sigma-delta modulator samples an input harmonic analog signal at a preset extremely high sampling frequency, and carries out low-order quantization on a difference value between two samples, so that a harmonic digital signal expressed by a low-order number, namely a sigma-delta code of a harmonic, is obtained; and then the sigma-delta code is sent to a digital decimation filter of a second part for decimation filtering, so that a harmonic digital signal modulated by the high-resolution linear pulse code is obtained, and the harmonic digital signal modulated by the high-resolution linear pulse code is used as a spectrum monitoring amplitude of the harmonic.
Further, referring to fig. 3, the present invention also proposes a harmonic correction apparatus including:
the signal receiving module A10 is used for receiving an input harmonic signal and generating a frequency spectrum monitoring amplitude;
the monitoring correction module A20 is configured to obtain a harmonic correction gain value corresponding to the harmonic signal in a preset harmonic correction gain value sequence table; taking the product of the spectrum monitoring amplitude and the harmonic correction gain value as the spectrum correction amplitude of the harmonic signal;
and the frequency spectrum output module A30 is used for forming a harmonic frequency spectrum according to the frequency spectrum correction amplitude and outputting the harmonic frequency spectrum.
Optionally, the monitoring and correcting module a20 is further configured to:
calculating to obtain an oversampling rate according to a preset sampling rate and a preset modulation frequency;
determining a digital decimation filter sinc based on the oversampling ratio3And converting the transfer function into an amplitude-frequency response expression;
calculating all harmonic correction gain values corresponding to the harmonic signals of all frequencies according to the amplitude-frequency response expression to generate a harmonic correction gain value sequence table;
and taking the harmonic correction gain value sequence table as a preset harmonic correction gain value sequence table.
Optionally, the monitoring and correcting module a20 is further configured to:
the digital decimation filter sinc3The transfer function of (a) is:
H(z)＝[(1-z-N)/(N×(1-z-1))]3，
the amplitude-frequency response expression is as follows:
H(f)＝|sin(Nπf/fMOD)/(N×sin(πf/fMOD))|3，
wherein H (z) is a digital decimation filter sinc3The transfer function of (a); n is an oversampling ratio; z is an argument of the transfer function H (z); h (f) is a digital decimation filter sinc3The amplitude-frequency response of; f. ofMODIs a preset modulation frequency; f is the argument of the amplitude-frequency response H (f).
Optionally, the monitoring and correcting module a20 is further configured to:
G(n)＝1/H(nfi)＝|(N×sin(πnfi/fMOD))/sin(Nπnfi/fMOD)|3
wherein f isiIs a preset frequency interval; n is the serial number of the frequency value, and G (n) is the correction gain value corresponding to the frequency value with the serial number of n; h (nf)i) To a frequency of nfiTime-digital decimation filter sinc3The amplitude-frequency response of; n is an oversampling ratio; f. ofMODIs a preset modulation frequency.
Optionally, the monitoring and correcting module a20 is further configured to:
and calculating a proportional value of the preset modulation frequency and the preset sampling rate, and taking the proportional value as an oversampling rate.
Optionally, the monitoring and correcting module a20 is further configured to:
and associating and storing the frequency values of the harmonic signals of all the frequencies and all the harmonic correction gain values to a preset table to generate a harmonic correction gain value sequence table.
Optionally, the signal receiving module a10 is further configured to:
receiving an input harmonic analog signal and converting the harmonic analog signal into a harmonic digital signal;
and converting the harmonic digital signal into a frequency spectrum monitoring amplitude.
In addition, the present invention further provides an electric energy metering device, which includes a memory, a processor, and a harmonic correction program stored on the memory and executable on the processor, and the processor implements the steps of the harmonic correction method according to the above embodiment when executing the harmonic correction program.
The specific implementation of the electric energy metering device of the present invention is basically the same as the embodiments of the harmonic correction method described above, and is not described herein again.
Furthermore, the present invention also proposes a readable storage medium, characterized in that the readable storage medium comprises a harmonic correction program, which when executed by a processor implements the steps of the harmonic correction method as described in the above embodiments.
The specific implementation of the readable storage medium of the present invention is substantially the same as the embodiments of the harmonic correction method described above, and will not be described herein again.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) as described above and includes instructions for enabling a terminal device (e.g., a television, a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present invention.
In the present invention, the terms "first", "second", "third", "fourth" and "fifth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance, and those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific situations.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although the embodiment of the present invention has been shown and described, the scope of the present invention is not limited thereto, it should be understood that the above embodiment is illustrative and not to be construed as limiting the present invention, and that those skilled in the art can make changes, modifications and substitutions to the above embodiment within the scope of the present invention, and that these changes, modifications and substitutions should be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A harmonic correction method, characterized by comprising the steps of:
receiving an input harmonic signal and generating a frequency spectrum monitoring amplitude;
acquiring a harmonic correction gain value corresponding to the harmonic signal in a preset harmonic correction gain value sequence table;
taking the product of the spectrum monitoring amplitude and the harmonic correction gain value as the spectrum correction amplitude of the harmonic signal;
and forming a harmonic spectrum according to the spectrum correction amplitude, and outputting the harmonic spectrum.
2. The harmonic correction method of claim 1 applied to a digital decimation filter sinc3(ii) a The step of receiving an input harmonic signal and generating a spectrum monitoring amplitude comprises the steps of:
calculating to obtain an oversampling rate according to a preset sampling rate and a preset modulation frequency;
determining a digital decimation filter sinc based on the oversampling ratio3And converting the transfer function into an amplitude-frequency response expression;
calculating all harmonic correction gain values corresponding to the harmonic signals of all frequencies according to the amplitude-frequency response expression to generate a harmonic correction gain value sequence table;
and taking the harmonic correction gain value sequence table as a preset harmonic correction gain value sequence table.
3. The harmonic correction method of claim 2, wherein the digital decimation filter sinc3The transfer function of (a) is:
H(z)＝[(1-z-N)/(N×(1-z-1))]3，
the amplitude-frequency response expression is as follows:
H(f)＝|sin(Nπf/fMOD)/(N×sin(πf/fMOD))|3，
wherein H (z) is a digital decimation filter sinc3The transfer function of (a); n is an oversampling ratio; z is an argument of the transfer function H (z); h (f) is a digital decimation filter sinc3The amplitude-frequency response of; f. ofMODIs a preset modulation frequency; f is the argument of the amplitude-frequency response H (f).
4. The harmonic correction method of claim 2, wherein the step of calculating all harmonic correction gain values corresponding to harmonic signals of all frequencies according to the magnitude-frequency response expression comprises:
G(n)＝1/H(nfi)＝|(N×sin(πnfi/fMOD))/sin(Nπnfi/fMOD)|3
wherein f isiIs a preset frequency interval; n is the serial number of the frequency value, and G (n) is the correction gain value corresponding to the frequency value with the serial number of n; h (nf)i) To a frequency of nfiTime-digital decimation filter sinc3The amplitude-frequency response of; n is an oversampling ratio; f. ofMODIs a preset modulation frequency.
5. The harmonic correction method of claim 2, wherein the step of calculating the oversampling rate based on the preset sampling rate and the preset modulation frequency comprises:
and calculating a proportional value of the preset modulation frequency and the preset sampling rate, and taking the proportional value as an oversampling rate.
6. The harmonic correction method of claim 2, wherein the step of generating a sequence list of harmonic correction gain values comprises:
and associating and storing the frequency values of the harmonic signals of all the frequencies and all the harmonic correction gain values to a preset table to generate a harmonic correction gain value sequence table.
7. The harmonic correction method of claim 1, wherein the step of receiving an input harmonic signal and generating a spectrally monitored amplitude comprises:
receiving an input harmonic analog signal and converting the harmonic analog signal into a harmonic digital signal;
and converting the harmonic digital signal into a frequency spectrum monitoring amplitude.
8. A harmonic correction apparatus, characterized in that the harmonic correction apparatus comprises:
the signal receiving module is used for receiving an input harmonic signal and generating a frequency spectrum monitoring amplitude;
the monitoring and correcting module is used for acquiring a harmonic correction gain value corresponding to the harmonic signal in a preset harmonic correction gain value sequence table; taking the product of the spectrum monitoring amplitude and the harmonic correction gain value as the spectrum correction amplitude of the harmonic signal;
and the frequency spectrum output module is used for forming a harmonic frequency spectrum according to the frequency spectrum correction amplitude and outputting the harmonic frequency spectrum.
9. An electrical energy metering device comprising a memory, a processor, and a harmonic correction program stored on the memory and executable on the processor, wherein: the harmonic correction program when executed by the processor implements the steps of the harmonic correction method of any one of claims 1 to 7.
10. A readable storage medium, characterized in that the readable storage medium has stored thereon a harmonic correction program which, when executed by a processor, implements the steps of the harmonic correction method according to any one of claims 1 to 7.
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