CN117294330A - Communication method and device of dual-mode module electric energy meter in power grid and electric energy meter - Google Patents
Communication method and device of dual-mode module electric energy meter in power grid and electric energy meter Download PDFInfo
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- H—ELECTRICITY
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B3/00—Line transmission systems
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The application discloses a communication method and device of a dual-mode module electric energy meter in a power grid and the electric energy meter, relates to the technical field of data transmission, and comprises the following steps: acquiring an input signal, randomly sampling the input signal, and acquiring a sampled discrete time signal; determining a local oscillator signal according to the target frequency range, wherein the local oscillator signal is used for amplifying or reducing an input signal according to the target frequency range; dividing the discrete time signal into a plurality of frequency components based on the discrete time signal and the local oscillator signal; obtaining a modulated analog signal according to the plurality of frequency components; the method can solve the problem that the transmission path fault in the prior art affects signal transmission, improves the efficiency of signal conversion, and enables signals to be transmitted in time.
Description
Technical Field
The present invention relates to the field of data transmission technologies, and in particular, to a communication method and apparatus for a dual-mode module electric energy meter in a power grid, and an electric energy meter.
Background
In order to monitor the service condition and the running state of the electric meters in real time, the electric meter data of each electric meter are generally collected through a collector, then the electric meter data are uploaded to a concentrator, the concentrator integrates or forwards the electric meter data so as to check the service condition of each electric meter, in the process of transmitting the electric meter data, a data transmission channel is generally constructed based on an HPLC (Highspeed Power Line Communication, high-speed power line carrier communication) module or an HRF (Highspeed Radio Frequency, high-speed micro-power wireless communication) module, and the data transmission channel is formed by the collector, the HPLC module and the concentrator so that the electric meter data are transmitted through the data transmission channel.
However, in the communication process of the electric energy meter, if a signal transmission path fails, communication is interrupted, so that the electric energy meter cannot communicate in time, and the communication method, the device and the electric energy meter of the double-module electric energy meter in the power grid are provided based on the fact that the electric energy meter fails to communicate in time.
Disclosure of Invention
According to the communication method and device for the dual-mode module electric energy meter in the power grid and the electric energy meter, the problem that in the prior art, a signal transmission path is affected by faults is solved, and the efficiency and accuracy of signal conversion are improved.
The embodiment of the application provides a communication method and device of a dual-mode module electric energy meter in a power grid and the electric energy meter, wherein the communication method comprises the following steps:
one or more technical solutions provided in the embodiments of the present application at least have the following technical effects or advantages:
acquiring an input signal, randomly sampling the input signal, and acquiring a sampled discrete time signal;
determining a local oscillator signal according to the target frequency range, wherein the local oscillator signal is used for amplifying or reducing an input signal according to the target frequency range;
dividing the discrete time signal into a plurality of frequency components based on the discrete time signal and the local oscillator signal; a modulated analog signal is obtained from the plurality of frequency components.
Extracting original data from the HPLC signal, and demodulating the original data into a baseband signal;
the baseband signal is converted into an RF signal according to the frequency range of the HPLC signal.
Matching the baseband signal with carrier signals with different frequencies, determining a converted target frequency range according to the frequency of the carrier signals, and determining a modulated RF signal according to the target frequency range;
the matching mode of the baseband signal is as follows:
s (t) =a×cos (2pi f1 t), when the baseband signal is "0";
s (t) =a×cos (2pi f2 t), when the baseband signal is "1";
wherein s (t) is a modulated RF signal, A is the amplitude of a baseband signal, f1 is the carrier signal frequency of "0" of the baseband signal, and f2 is the carrier signal frequency of "1" of the baseband signal;
dividing the baseband signal into a real part and an imaginary part according to the matching result of the baseband signal and the carrier signal;
acquiring carrier signals corresponding to the real part and the imaginary part of the baseband signal, and determining a modulated RF signal according to the carrier signal frequency;
the modulation scheme for the baseband signal is as follows:
s(t) = Re{A * cos(2πfct) * I(t)} - Im{A * sin(2πfct) * Q(t)}；
where s (t) is the modulated RF signal, a is the amplitude of the baseband signal, fc is the carrier signal frequency, I (t) and Q (t) are the real and imaginary parts of the baseband signal, re represents the real part of the RF signal, and Im represents the imaginary part of the RF signal.
Acquiring a signal of mixing an HPLC signal and an RF signal, and taking the signal as an input signal;
according to the target frequency range, determining a local oscillator frequency corresponding to the input signal, and carrying out frequency mixing operation on the input signal according to the local oscillator frequency;
dividing an input signal into a plurality of frequency components, and acquiring frequency components corresponding to a target frequency range;
and (3) filtering the frequency components, amplifying the filtered frequency component signals, and outputting frequency-converted RF signals.
Sampling an input signal, sampling the input signal according to a certain time interval, and outputting the input signal as a discrete time signal; the certain time interval refers to the sampling frequency of a discrete time signal; the sampling frequency of the discrete-time signal is at least twice the highest frequency of the input signal;
filtering the discrete time signals to obtain filtered discrete time signals;
determining a local oscillation signal according to the frequency range of the RF signal, and determining an output analog signal according to the discrete time signal and the local oscillation signal;
from the analog signal, an output RF signal is determined.
According to the discrete time signal and the local oscillation signal, the output analog signal expression formula is as follows:
y(n) = x(n) * cos(2πf_c nT) - x(n) * sin(2πf_c nT)；
wherein y (n) is an analog signal, x (n) is a discrete time signal, f_c is the frequency of the local oscillator signal, n is a discrete time point, and T is a sampling interval.
Acquiring an input signal and a target frequency range, determining a local oscillation signal, converting the local oscillation signal and the input signal into complex forms, and sequentially acquiring real parts and imaginary parts of the local oscillation signal and the input signal;
and acquiring the finally output analog RF signal according to the real part and the imaginary part of the local oscillation signal and the input signal.
Acquiring the input frequency of an input signal, and reducing the frequency of the input signal according to a preset frequency division ratio;
acquiring a delay signal frequency based on a target frequency range, and carrying out delay processing on an input signal according to the delay signal frequency to obtain a delay signal;
and modulating the delay signal, and outputting a modulated analog HPLC signal.
A communication device for a dual-mode module power meter in a power grid, comprising: the signal sampling module is used for sampling the input signal according to a certain time interval, and the sampling frequency is at least twice the highest frequency of the input signal;
the signal filtering module is used for filtering the input signal according to the target frequency range and dividing the target signal into a plurality of frequency components according to discrete time;
the first conversion module is used for converting the HPLC signal into an RF signal according to the target frequency range;
and the second conversion module is used for converting the RF signal into an HPLC signal according to the target frequency range.
A communication electric energy meter of a double-module electric energy meter in a power grid comprises a double-module and a communication module;
the dual-mode module is used for selecting a communication mode of the electric energy meter according to the signal conversion frequency;
the communication module is used for establishing connection of the external terminal according to the converted frequency.
One or more technical solutions provided in the embodiments of the present application at least have the following technical effects or advantages:
through adjusting input signal and local oscillator signal, output after converting HPLC signal and RF signal into digital signal, can make when carrying out a large amount of data signal conversion, the data signal accuracy that obtains is higher, reduces the influence of a large amount of data conversion to efficiency and accuracy.
Drawings
FIG. 1 is a schematic flow chart of input signal processing of a communication method of a dual-module electric energy meter in a power grid;
FIG. 2 is a schematic flow chart of HPLC signal conversion RF signal of a communication method of a dual-mode module electric energy meter in a power grid;
FIG. 3 is a schematic flow chart of baseband signal modulation of a communication method of a dual-mode module electric energy meter in a power grid;
FIG. 4 is a schematic flow chart of the frequency range adjustment of the HPLC signal conversion RF signal in the communication method of the dual-module electric energy meter in the power grid;
FIG. 5 is a schematic flow chart of a first method of communication of a dual-mode module electric energy meter in a power grid based on digital signal processing of an input signal;
FIG. 6 is a schematic flow chart of a second method of communication of a dual-mode module power meter in a power grid based on digital signal processing of an input signal;
fig. 7 is a schematic flow chart of converting an input signal of a communication method of a dual-mode module electric energy meter in a power grid into an HPLC signal;
FIG. 8 is a schematic diagram of a communication device of a dual-module power meter in a power grid;
fig. 9 is a schematic diagram of a system for a communication electric energy meter of a dual-mode module electric energy meter in a power grid.
Detailed Description
It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.
The technical scheme in the prior art has the following technical problems:
the existing dual-mode module electric energy meter has two communication modes: HPLC communication mode and RF communication mode. The HPLC communication mode realizes communication through a power line, the RF communication mode realizes communication through radio frequency, and the electric energy meter of the dual-mode module can carry out data transmission in different communication modes through mutual conversion between the communication modes. However, in the communication process, adjustment needs to be performed between the HPLC and RF communication modes, so as to realize reliability and stability of electric energy meter communication.
The invention can switch the communication modes in time through the following two points, thereby improving the reliability and stability of the electric energy meter communication:
first point: in HPLC communication mode, data transmission is performed through a power line, so that HPLC signals need to be converted into RF signals in order to communicate on radio frequencies; the invention provides an HPLC to RF converter which receives the HPLC signal and converts it to an RF signal; the converter can demodulate and modulate the HPLC signal into an RF signal by using a digital signal processing technology; while converting the low frequency signal of the HPLC signal into the high frequency signal of the RF signal.
Second point: in the RF communication mode, data transmission is performed by radio frequency; therefore, conversion of the RF signal to an HPLC signal is required in order to communicate over the power line; the invention is mainly provided with an RF-to-HPLC converter which receives the RF signal and converts it into an HPLC signal. The converter can use the radio frequency front-end module to demodulate and modulate signals; the converter also needs to perform frequency conversion to convert the high frequency signal of the RF signal into the low frequency signal of the HPLC signal.
Wherein HPLC and RF communication techniques may use different communication protocols, and thus require protocol conversion to ensure proper transmission of data between different communication modes; in HPLC to RF conversion, data of the HPLC protocol needs to be converted into data of the RF protocol; this may involve conversion in terms of data format, encoding, decoding, etc.
In RF-to-HPLC conversion, it is necessary to convert data of the RF protocol into data of the HPLC protocol. Again, this involves conversion in terms of data format, encoding, decoding, etc.
In summary, the invention realizes the stable communication of the electric energy meter by adjusting the protocol conversion methods of the two communication modes.
For the interconversion between HPLC signals and RF signals, as shown in fig. 1, the processing mode for the input signal can be implemented by the following steps:
s1, acquiring an input signal, randomly sampling the input signal, and acquiring a sampled discrete time signal;
s2, determining a local oscillator signal according to the target frequency range, wherein the local oscillator signal is used for amplifying or reducing an input signal according to the target frequency range;
s3, dividing the discrete time signal into a plurality of frequency components based on the discrete time signal and the local oscillation signal; a modulated analog signal is obtained from the plurality of frequency components.
The invention mainly determines the local oscillation signal used according to the required target frequency range, obtains the processed analog signal according to the local oscillation signal and the input discrete time signal, and the output analog signal can be an RF signal or an HPLC signal.
The key point is that the method for converting the HPLC signal into the RF signal can improve the communication time and stability of the electric energy meter by realizing the rapid conversion of the HPLC signal, so the application provides the following scheme, as shown in fig. 2, the specific scheme is as follows:
s101, extracting original data from an HPLC signal, and demodulating the original data into a baseband signal;
the HPLC signal is a power carrier signal, the frequency range of the HPLC signal is usually below 2MHz, the original data is usually extracted from the HPLC signal, and the demodulator is used to demodulate the original data and convert the demodulated original data into a recognizable signal, namely a baseband signal.
S102, converting the baseband signal into an RF signal according to the frequency range of the HPLC signal. In general, a baseband signal is converted into a high-frequency signal of an RF signal through modulation, and how to select a processing mode of the signal in the modulation process affects the conversion effect of the signal. The common modulation method comprises FSK modulation and QAM modulation, and the invention improves the effect during modulation by combining FSK and QAM modulation modes.
Specifically, as shown in fig. 3, the implementation of modulation on the baseband signal is as follows:
when the acquired baseband signal is a binary signal sequence, frequency shift keying FSK is used for matching the baseband signal with carrier signals with different frequencies, so that signal conversion is realized.
S201, matching a baseband signal with carrier signals with different frequencies, determining a converted target frequency range according to the frequency of the carrier signals, and determining a modulated RF signal according to the target frequency range;
when the baseband signal is matched with the carrier signal, the frequency of the matched carrier signal is marked as f1 when the baseband signal is 0, the frequency of the carrier signal is marked as f2 when the baseband signal is 1, and the matched baseband signal is output as an RF signal.
Specifically, the matching manner of the baseband signal is as follows:
s (t) =a×cos (2pi f1 t), when the baseband signal is "0";
s (t) =a×cos (2pi f2 t), when the baseband signal is "1";
where s (t) is a modulated RF signal, a is the amplitude of the baseband signal, f1 is the carrier signal frequency of "0" for the baseband signal, and f2 is the carrier signal frequency of "1" for the baseband signal.
0 and 1 are phases corresponding to the carrier signal frequency, the frequency shift keying FSK is used for transmitting digital information through the carrier frequency, the baseband signal is matched with the carrier signal according to the amplitude, and the frequency is switched according to the different carrier signals corresponding to the baseband signal, so that the phase of the baseband signal is adjusted. The modulating process is to take the waveform of the baseband signal as the amplitude, so as to change the amplitude of the carrier signal, further change the frequency range of the HPLC signal, so that a higher frequency range can be achieved, and the signal can be converted into an RF signal to realize the communication of the electric energy meter dual-mode module.
For the modulation mode of the RF signal, a Quadrature Amplitude Modulation (QAM) modulation mode can be used, and the baseband signal is processed at the same time to divide the baseband signal into a real part and an imaginary part, wherein the real part and the imaginary part correspond to different carrier signals, so that the efficiency and the accuracy of the modulation of the baseband signal are improved; specifically, the following is shown:
s202, dividing the baseband signal into a real part and an imaginary part according to a matching result of the baseband signal and the carrier signal;
s203, carrier signals corresponding to the real part and the imaginary part of the baseband signal are acquired, and the modulated RF signals are determined according to the carrier signal frequency.
The modulation scheme for the baseband signal is as follows:
s(t) = Re{A * cos(2πfct) * I(t)} - Im{A * sin(2πfct) * Q(t)}；
where s (t) is the modulated RF signal, a is the amplitude of the baseband signal, fc is the carrier signal frequency, I (t) and Q (t) are the real and imaginary parts of the baseband signal, re represents the real part of the RF signal, and Im represents the imaginary part of the RF signal.
The real part is the projection or component of the complex number on the real axis, which is the part of a real number, usually denoted by Re; the imaginary part represents the projection or component of the complex number on the imaginary axis, which is the imaginary part of the complex number, and the imaginary part is generally represented by the symbol Im.
The waveform of the real part and the imaginary part of the RF signal is determined according to the carrier signal frequency corresponding to the real part and the imaginary part, and the amplitude of the influence of the carrier signal frequency between the real part and the imaginary part is determined according to the set trigonometric function, thereby determining the obtained carrier signal.
A complex number may be represented by a combination of real and imaginary parts, in the form a+bi, where a is the real part, b is the imaginary part, and i is the imaginary unit, satisfying i_j= -1.
The real and imaginary parts play an important role in the geometrical interpretation of the complex numbers. The complex number may be represented as a point on the complex plane, with the real part corresponding to the abscissa on the complex plane and the imaginary part corresponding to the ordinate on the complex plane. The real and imaginary parts determine the position of the complex number in the complex plane, which together express the magnitude and direction of the complex number.
For example, for complex number z=3+4i, its real part is 3 and its imaginary part is 4. This complex number is represented on the complex plane as a point (3, 4), at a distance of 5 from the origin, and at an angle arctan (4/3). The real and imaginary parts provide important information about the complex position and nature.
In signal processing and communication systems, the real and imaginary parts are often used to represent modulated signals, spectral characteristics of complex signals, orthogonality of signals, etc. The computation and processing of real and imaginary parts also plays an important role in many fields, such as signal processing, image processing, control systems, etc.
In this step, the baseband signal is divided into a real part and an imaginary part, the real part and the imaginary part correspond to different carrier signals, and the waveform of the modulated RF signal can be determined according to the carrier signal frequencies of the real part and the imaginary part; the real and imaginary parts of the modulated RF signal can be determined by the baseband signal and carrier signal frequencies, so that the frequency range of the RF signal is known.
In one embodiment of the invention, the mode of converting the HPLC signal into the RF signal can also be realized by directly adjusting the frequency range, and the efficiency and effect of signal conversion can be improved according to the direct modification of the frequency range; as shown in fig. 4, a specific implementation is as follows:
s301, acquiring a signal obtained by mixing an HPLC signal and an RF signal, and taking the signal as an input signal.
At the moment, the HPLC signal and the RF signal are mixed and input into the mixer, and on the premise of not considering the type of the signal, only the factors such as the frequency range, the power requirement and the linearity of the mixer are considered; and determining the conversion effect of the HPLC signal according to the frequency range of the signal and the local oscillation frequency set by the mixer.
S302, determining a local oscillation frequency corresponding to the input signal according to the target frequency range, and carrying out frequency mixing operation on the input signal according to the local oscillation frequency.
The local oscillator frequency is a parameter on the mixer that is used to convert the input signal to the desired frequency range; the target frequency range refers to the frequency range of RF communication, and the local oscillation frequency set according to the target frequency range enables the HPLC signal to be converted into the RF frequency range.
S303, dividing the input signal into a plurality of frequency components, and acquiring frequency components corresponding to the target frequency range.
During mixing operation, an input signal is divided into a plurality of frequency components, frequency components in a target frequency range are selected for processing, abnormal frequency components in the frequency components are removed by filtering, and signals in the target frequency range are amplified, so that the obtained signal expression form is more complete and conversion is more convenient.
S304, filtering the frequency components, amplifying the filtered frequency component signals, and outputting frequency-converted RF signals.
Since the HPLC signal and the RF signal have different ranges, the frequency range of the RF signal is large, and at this time, it is necessary to select a frequency component close to the set target frequency range for the input signal, divide the frequency component by an unnecessary frequency component, and amplify the frequency component to the frequency range of the RF signal, thereby obtaining the converted RF signal.
In this step, all the input signals are converted into the desired RF signals without considering the type of the input signals, thereby reducing the limitation in frequency conversion and improving the effect of frequency conversion.
Preferably, the input signal is converted into a digital signal, and frequency conversion is achieved according to the processing of the digital signal, as shown in fig. 5, and the first method for processing the input signal based on the digital signal is as follows:
s401, sampling an input signal, sampling the input signal according to a certain time interval, and outputting the input signal as a discrete time signal; the certain time interval refers to the sampling frequency of a discrete time signal; the discrete-time signal should have a periodic repeating characteristic at intervals of 2pi and be point-symmetrical at a folding frequency, i.e., ω=pi, and should be converted when the sampling frequency of the discrete-time signal is at least twice the highest frequency of the input signal.
In the step, the input signal is a digital signal, and the input signal is sampled according to the set sampling frequency according to the specific digital signal processing, so as to obtain signal information corresponding to each specific time value in discrete time, thereby obtaining signals which are discrete enough and meet the processing.
S402, filtering the discrete time signals to obtain filtered discrete time signals;
the step uses a digital filter to process the discrete time signal to filter out unwanted frequency components; in the frequency domain, the digital filter performs two-dimensional filtering on the input signal with a transfer function H (z), where z is a complex variable; the input discrete time signals are accumulated or multiplied to select the output discrete time signals.
S403, determining a local oscillation signal according to the frequency range of the RF signal, and determining an output analog signal according to the discrete time signal and the local oscillation signal; the local oscillation signal is used for converting the frequency range of the discrete time signal into the frequency range of a digital signal corresponding to the RF signal;
preferably, according to the discrete time signal and the local oscillation signal, the output analog signal expression formula is as follows:
y(n) = x(n) * cos(2πf_c nT) - x(n) * sin(2πf_c nT)；
wherein y (n) is an analog signal, x (n) is a discrete time signal, f_c is the frequency of the local oscillator signal, n is a discrete time point, and T is a sampling interval. The discrete time point corresponding to n is a specific time value or time on the discrete time, T is a time interval of a set sampling frequency, and the signal range of the sampling point corresponding to the local oscillation signal frequency and the input discrete time signal can be known by subtracting a cosine function and a sine function corresponding to the discrete time signal, so that an analog signal which can be converted into an RF signal is obtained.
The above formula is only used for reference, and it should be noted that when determining the range of the analog signal according to the discrete time signal and the local oscillator signal, the frequency of the local oscillator signal needs to be adjusted according to the target range, so as to adjust the frequency range of signal conversion. And meanwhile, after the analog signal is determined, the analog signal needs to be converted into a normal communication signal from a digital signal mode.
S404, determining an output RF signal according to the analog signal.
y(t) = ∑[y(n) * δ(t -nT)]；
Where y (T) is an RF signal, y (n) is an analog signal, δ (T) is a unit pulse function, n is a discrete time point, and T is a sampling interval. The product of nT represents a specific time point when each discrete time signal is acquired, delta (t-nT) is obtained as a unit pulse at a time point corresponding to each analog signal, and a unit pulse function is used for representing corresponding impact of the signals, such as amplitude response, phase-frequency response and the like of the signals, so that stability of output amplitude and frequency when the analog signals are converted into RF signals is determined, and thus the sufficiently accurate RF signals are obtained.
Preferably, when processing signal conversion using trigonometric functions, it is difficult to cope with a large amount of signal data, so that the efficiency of data conversion is reduced, and in order to reduce the influence of a large amount of repeated data on signal processing, in one embodiment of the present invention, as shown in fig. 6, the second processing manner of input signals based on digital signals may be further implemented as follows:
s501, acquiring an input signal and a target frequency range, determining a local oscillation signal, converting the local oscillation signal and the input signal into complex forms, and sequentially acquiring real parts and imaginary parts of the local oscillation signal and the input signal.
For example, assume that the input signal is x (n), the local oscillator signal is y (n), where n is a discrete point in time. X (n) and y (n) are expressed as complex numbers, and can be obtained:
x(n) = x_r(n) + jx_i(n)；
y(n) = y_r(n) + jy_i(n)；
wherein x_r (n) and x_i (n) are the real and imaginary parts of x (n), respectively, y_r (n) and y_i (n) are the real and imaginary parts of y (n), respectively, and j is the imaginary unit.
The signal data generally has two parts, a real part and an imaginary part, which can be represented by complex numbers; complex numbers are used to describe signals or data having phase and amplitude information; complex numbers are mathematical objects composed of real and imaginary numbers, typically expressed in the form: a+bi, where a is the real part, b is the imaginary part, and i is the imaginary unit. The real part represents the projection of the complex number on the real number axis, and the imaginary part represents the projection of the complex number on the imaginary number axis; complex forms of data can more fully describe the characteristics of a signal because they can capture both phase and amplitude information.
S502, obtaining the finally output analog RF signal according to the real part and the imaginary part of the local oscillation signal and the input signal.
Multiplying x (n) and y (n) to obtain a final output analog RF signal z (n):
z(n) = x(n) * y(n) = (x_r(n) + jx_i(n)) * (y_r(n) + jy_i(n))；
= (x_r(n)y_r(n) - x_i(n)y_i(n)) + j(x_r(n)y_i(n) + x_i(n)y_r(n))；
where (x_r (n) y_r (n) -x_i (n) y_i (n)) is the real part of the analog signal z (n) and (x_r (n) y_i (n) +x_i (n) y_r (n)) is the imaginary part of the analog signal z (n).
Thus, the final output analog RF signal can be expressed by the following formula:
real(z(n)) = x_r(n)y_r(n) - x_i(n)y_i(n)；
imag(z(n)) = x_r(n)y_i(n) + x_i(n)y_r(n)；
where real (z (n)) is the real part of the analog RF signal and imag (z (n)) is the imaginary part of the analog RF signal. Therefore, the efficiency of signal conversion can be improved, and the accuracy of signal processing can be improved. The final output complex signal is the analog signal that is output.
For ease of understanding, the present invention provides the following exemplary illustrations:
let us assume that we have the following input signals and local oscillator signals:
input signal x (n) = [1, 2, 3, 4];
local oscillation signal y (n) = [0, 1, 0, -1];
first, an input signal and a local oscillation signal are expressed as complex forms:
x(n) = [1 + j0, 2 + j0, 3 + j0, 4 + j0]；
y(n) = [0 + j0, 1 + j0, 0 + j0, -1 + j0]；
then, the input signal and the local oscillation signal are multiplied to obtain an analog signal z (n):
z(n) = x(n) * y(n)；
= [(1 + j0) * (0 + j0), (2 + j0) * (1 + j0), (3 + j0) * (0 + j0), (4 + j0) * (-1 + j0)]；
= [0 + j0, 2 + j0, 0 + j0, -4 + j0]；
finally, the analog RF signal z (n) is decomposed into real and imaginary parts:
real (z (n)) = [0, 2, 0, -4];
imaginary imag (z (n))= [0, 0, 0, 0];
thus we have obtained mixed real and imaginary signals. By the complex operation method, the calculation process of the digital mixer can be simplified, the calculation of trigonometric functions is avoided, and the calculation efficiency and accuracy are improved.
In this embodiment, by converting the HPLC signal into the analog RF signal, when the HPLC signal and the RF signal are mixed, the frequency of the output signal can be adjusted too fast, so as to improve the communication effect and switch the communication modes in time.
In order to make the obtained signal conversion frequency faster, the signal communication effect obtained by outputting is better, in one embodiment of the present invention, as shown in fig. 7, the signal conversion manner may be the following manner:
the technical scheme in the embodiment of the application at least has the following technical effects or advantages:
through adjusting input signal and local oscillator signal, output after converting HPLC signal into digital signal, can make when carrying out a large amount of data signal conversion, the data signal accuracy that obtains is higher, reduces the influence of a large amount of data conversion to efficiency and accuracy.
In one embodiment of the invention, when the input signal is required to be converted into an HPLC signal, dividing the input signal according to a set output frequency, and reducing the input frequency to obtain an input signal close to the HPLC frequency range;
s601, obtaining the input frequency of the input signal, and reducing the frequency of the input signal according to a preset frequency division ratio.
As implemented using the following formula,
division ratio = input frequency/output frequency;
the input frequency refers to the frequency of the input signal, and the output frequency refers to the frequency of the signal after frequency division. The division ratio must be an integer or a fraction. For example, if the input frequency is 100 MHz and it is required to divide it by 10 MHz, then the division ratio is:
division ratio = 100 MHz/10 MHz = 10;
this means that one output period is generated every 10 input periods, and frequency division by a factor of 10 is achieved, so that the input signal input too high is reduced.
Further, the frequency of the input signal is reduced according to the set delay signal frequency until the input signal frequency is within the target frequency range, wherein the target frequency range is the frequency range corresponding to the HPLC signal, and the frequency range of the HPLC signal is reduced relative to the frequency range of the RF signal, so that the frequency is reduced in a delayed mode.
S602, acquiring a delay signal frequency based on a target frequency range, and carrying out delay processing on an input signal according to the delay signal frequency to obtain a delay signal;
delay modulation is a method of reducing the frequency of a signal by multiplying the signal with a varying delay signal. The formula for delay modulation can be expressed as:
delay signal=input signal×cos (2pi_delay×t)
The delay signal is a signal obtained after delay processing, the input signal is an original signal, f_delay is the frequency of the delay signal, and t is a time variable.
In delay modulation, the frequency of the delayed signal determines the degree of frequency reduction of the signal. By adjusting the frequency of the delay signal, different degrees of frequency reduction can be achieved. For example, if the frequency of the delay signal is f_delay, then the frequency of the output signal will be reduced to f_delay/2.
It is noted that delay modulation typically requires a multiplication between the input signal and the delay signal. In practical applications, delay modulation may be implemented using analog circuitry or Digital Signal Processing (DSP) systems, and the specific implementation and formulation may vary.
S603, modulating the delay signal, and outputting a modulated analog HPLC signal;
the processing form for the delayed signal can be expressed as:
[y(t) = f(x(t - tau))]
where x (t) is the delay signal, y (t) is the modulated analog HPLC signal, tau is the delay time, and f (x (t-tau)) represents the modulation function for modulating the delay signal.
The modulation function may vary depending on the particular modulation scheme, such as phase modulation, frequency modulation, amplitude modulation, and the like. The specific modulation function form and parameters will vary depending on the modulation scheme selected. When the delay time and the delay signal change, the frequency of the obtained HPLC signal also changes, so that the display condition of the signal in the asynchronous time domain is obtained.
In this embodiment, the input signals are respectively delayed and modulated, so that the obtained signals can be converted in time according to the frequency of the signals, thereby improving the communication mode of the electric energy meter.
In one embodiment of the present invention, as shown in fig. 8, there is provided a communication device of a dual-mode module electric energy meter in a power grid, including:
the signal sampling module is used for sampling the input signal according to a certain time interval, and the sampling frequency is at least twice the highest frequency of the input signal;
the signal filtering module is used for filtering the input signal according to the target frequency range and dividing the target signal into a plurality of frequency components according to discrete time;
the first conversion module is used for converting the HPLC signal into an RF signal according to the target frequency range;
the second conversion module is used for converting the RF signal into an HPLC signal according to the target frequency range;
after discrete signals are acquired through the signal sampling module, filtering is carried out according to the obtained discrete time signals and the target frequency range, and the filtered discrete time signals are converted into required signals according to the required signal range.
In one embodiment of the present invention, there is provided a communication electric energy meter of a dual-mode module electric energy meter in a power grid, as shown in fig. 9, including: a dual mode module and a communication module.
The dual-mode module is used for selecting a communication mode of the electric energy meter according to the signal conversion frequency.
The communication module is used for establishing connection of the external terminal according to the converted frequency.
Specifically, the communication modes of the electric energy meter include an HPLC communication mode and an RF communication mode; the HPLC communication mode enables communication via a power line and the RF communication mode enables communication via radio frequency.
In an HPLC communication mode, the electric energy meter communicates with other equipment through a power line; the power line carrier signal is used for data transmission, and the power line carrier signal has the characteristics of long communication distance, strong anti-interference capability and the like.
In the RF communication mode, the electric energy meter communicates with other devices via radio frequencies; the wireless data transmission device can utilize radio frequency to carry out data transmission, and has the characteristics of short communication distance, high transmission speed and the like.
The dual-mode module electric energy meter can select a proper communication mode according to different communication requirements so as to adapt to different environments and application scenes. Meanwhile, the electric energy meter also has a dual-mode module design, so that the electric energy meter can support HPLC and RF communication simultaneously, and further communication selection and flexibility are provided.
The invention also provides an electronic device, which comprises:
at least one processor;
a memory;
at least one application, wherein the at least one application is stored in memory and configured to be executed by at least one processor, the at least one application configured to: and executing the communication method of the dual-mode module electric energy meter in the power grid.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A communication method of a dual-mode module electric energy meter in a power grid, comprising the steps of: acquiring an input signal, randomly sampling the input signal, and acquiring a sampled discrete time signal;
determining a local oscillator signal according to the target frequency range, wherein the local oscillator signal is used for amplifying or reducing an input signal according to the target frequency range;
dividing the discrete time signal into a plurality of frequency components based on the discrete time signal and the local oscillator signal; a modulated analog signal is obtained from the plurality of frequency components.
2. The method for communication of a dual-mode module electric energy meter in a power grid according to claim 1, wherein the method is characterized in that raw data is extracted from HPLC signals and demodulated into baseband signals;
the baseband signal is converted into an RF signal according to the frequency range of the HPLC signal.
3. The communication method of a dual-mode module electric energy meter in a power grid according to claim 1, wherein the baseband signal is matched with carrier signals with different frequencies, a converted target frequency range is determined according to the frequency of the carrier signals, and a modulated RF signal is determined according to the target frequency range;
the matching mode of the baseband signal is as follows:
s (t) =a×cos (2pi f1 t), when the baseband signal is "0";
s (t) =a×cos (2pi f2 t), when the baseband signal is "1";
wherein s (t) is a modulated RF signal, A is the amplitude of a baseband signal, f1 is the carrier signal frequency of "0" of the baseband signal, and f2 is the carrier signal frequency of "1" of the baseband signal;
dividing the baseband signal into a real part and an imaginary part according to the matching result of the baseband signal and the carrier signal;
acquiring carrier signals corresponding to the real part and the imaginary part of the baseband signal, and determining a modulated RF signal according to the carrier signal frequency;
the modulation scheme for the baseband signal is as follows:
s(t) = Re{A * cos(2πfct) * I(t)} - Im{A * sin(2πfct) * Q(t)}；
where s (t) is the modulated RF signal, a is the amplitude of the baseband signal, fc is the carrier signal frequency, I (t) and Q (t) are the real and imaginary parts of the baseband signal, re represents the real part of the RF signal, and Im represents the imaginary part of the RF signal.
4. The method for communication of a dual-mode module electric energy meter in a power grid according to claim 1, wherein a signal obtained by mixing an HPLC signal and an RF signal is regarded as an input signal;
according to the target frequency range, determining a local oscillator frequency corresponding to the input signal, and carrying out frequency mixing operation on the input signal according to the local oscillator frequency;
dividing an input signal into a plurality of frequency components, and acquiring frequency components corresponding to a target frequency range;
and (3) filtering the frequency components, amplifying the filtered frequency component signals, and outputting frequency-converted RF signals.
5. The communication method of a dual-mode module electric energy meter in a power grid according to claim 1, wherein the input signal is sampled, and the input signal is sampled at a certain time interval and output as a discrete time signal; the certain time interval refers to the sampling frequency of a discrete time signal; the sampling frequency of the discrete-time signal is at least twice the highest frequency of the input signal;
filtering the discrete time signals to obtain filtered discrete time signals;
determining a local oscillation signal according to the frequency range of the RF signal, and determining an output analog signal according to the discrete time signal and the local oscillation signal;
from the analog signal, an output RF signal is determined.
6. The method for communication of a dual-mode module electric energy meter in a power grid according to claim 5, wherein the output analog signal expression formula is as follows according to the discrete time signal and the local oscillation signal:
y(n) = x(n) * cos(2πf_c nT) - x(n) * sin(2πf_c nT)；
wherein y (n) is an analog signal, x (n) is a discrete time signal, f_c is the frequency of the local oscillator signal, n is a discrete time point, and T is a sampling interval.
7. The communication method of a dual-mode module electric energy meter in a power grid according to claim 1, wherein an input signal and a target frequency range are acquired, a local oscillation signal is determined, the local oscillation signal and the input signal are converted into complex forms, and a real part and an imaginary part of the local oscillation signal and the input signal are sequentially acquired;
and acquiring the finally output analog RF signal according to the real part and the imaginary part of the local oscillation signal and the input signal.
8. The communication method of a dual-mode module electric energy meter in a power grid according to claim 1, wherein the input frequency of an input signal is obtained, and the frequency of the input signal is reduced according to a preset frequency division ratio;
acquiring a delay signal frequency based on a target frequency range, and carrying out delay processing on an input signal according to the delay signal frequency to obtain a delay signal;
and modulating the delay signal, and outputting a modulated analog HPLC signal.
9. A communication device of a dual-mode module electric energy meter in a power grid, comprising: the signal sampling module is used for sampling the input signal according to a certain time interval, and the sampling frequency is at least twice the highest frequency of the input signal;
the signal filtering module is used for filtering the input signal according to the target frequency range and dividing the target signal into a plurality of frequency components according to discrete time;
the first conversion module is used for converting the HPLC signal into an RF signal according to the target frequency range;
and the second conversion module is used for converting the RF signal into an HPLC signal according to the target frequency range.
10. The communication electric energy meter of the dual-mode module in the electric network is characterized by comprising a dual-mode module and a communication module;
the dual-mode module is used for selecting a communication mode of the electric energy meter according to the signal conversion frequency;
the communication module is used for establishing connection of the external terminal according to the converted frequency.
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| JP2015220524A (en) * | 2014-05-15 | 2015-12-07 | 日本電信電話株式会社 | Distributed wireless communication base station system and communication method |
| CN105450258A (en) * | 2015-11-12 | 2016-03-30 | 北京华美讯联科技有限公司 | Wireless bridging carrier communication device |
| CN112260723A (en) * | 2020-10-23 | 2021-01-22 | 全球能源互联网研究院有限公司 | Fusion transmitting device, fusion receiving method, fusion system and fusion equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015220524A (en) * | 2014-05-15 | 2015-12-07 | 日本電信電話株式会社 | Distributed wireless communication base station system and communication method |
| CN105450258A (en) * | 2015-11-12 | 2016-03-30 | 北京华美讯联科技有限公司 | Wireless bridging carrier communication device |
| CN112260723A (en) * | 2020-10-23 | 2021-01-22 | 全球能源互联网研究院有限公司 | Fusion transmitting device, fusion receiving method, fusion system and fusion equipment |
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Application publication date: 20231226 |