Harmonic extraction method, device and equipment based on phase-locked amplifier and storage medium

文档序号：490286 发布日期：2022-01-04 浏览：43次中文

阅读说明：本技术 基于锁相放大器的谐波提取方法、装置、设备和存储介质 (Harmonic extraction method, device and equipment based on phase-locked amplifier and storage medium ) 是由曹旺胡边万元潘平衡刘章进唐伟于 2021-09-27 设计创作，主要内容包括：本申请涉及一种基于锁相放大器的谐波提取方法、装置、设备和存储介质。该方法包括：获取变压器油析出气体中含有光谱吸收信息的信号波,依据信号波的调制频率,将信号波和正弦参考信号、余弦参考信号一起作为输入信号；将输入信号经过乘法器后得到第一提取信号后,再通过CIC滤波器进行积分和抽取；在第一提取信号通过所述CIC滤波器后得到第二提取信号,将第二提取信号通过IIR滤波器进行谐波处理；在第二提取信号通过IIR滤波器后得到目的提取信号,将目的提取信号通过正交器进行整合,获取信号波的谐波。本申请将CIC滤波器与IIR滤波器联合使用,利用了CIC降采样的功效,又利用了IIR滤波器滤波效果好、计算量少的优点。(The application relates to a harmonic extraction method, a harmonic extraction device, harmonic extraction equipment and a storage medium based on a phase-locked amplifier. The method comprises the following steps: acquiring a signal wave containing spectral absorption information in the gas precipitated from the transformer oil, and taking the signal wave, a sine reference signal and a cosine reference signal as input signals according to the modulation frequency of the signal wave; after an input signal passes through a multiplier to obtain a first extraction signal, integrating and extracting the first extraction signal through a CIC filter; obtaining a second extraction signal after the first extraction signal passes through the CIC filter, and carrying out harmonic processing on the second extraction signal through an IIR filter; and obtaining a target extraction signal after the second extraction signal passes through an IIR filter, and integrating the target extraction signal through an orthogonalizer to obtain the harmonic wave of the signal wave. According to the method and the device, the CIC filter and the IIR filter are jointly used, the CIC down-sampling effect is utilized, and the advantages of good filtering effect and small calculation amount of the IIR filter are utilized.)

1. A method for harmonic extraction based on a lock-in amplifier, the method comprising:

acquiring a signal wave containing spectral absorption information in gas precipitated from transformer oil, and taking the signal wave, a sine reference signal and a cosine reference signal as input signals according to the modulation frequency of the signal wave;

the input signal is processed by a multiplier to obtain a first extraction signal, and then the first extraction signal is integrated and extracted by a CIC filter;

obtaining a second extraction signal after the first extraction signal passes through the CIC filter, and carrying out harmonic processing on the second extraction signal through an IIR filter;

and obtaining a target extraction signal after the second extraction signal passes through the IIR filter, and integrating the target extraction signal through an orthogonalizer to obtain the harmonic wave of the signal wave.

2. The harmonic extraction method based on the lock-in amplifier according to claim 1, wherein the step of subjecting the input signal to a multiplier to obtain a first extracted signal, and then subjecting the first extracted signal to integration and decimation by a CIC filter comprises:

acquiring an integral length of the first extraction signal, and performing integral processing on the first extraction signal according to the integral length to reduce random noise of the first extraction signal;

increasing the amplitude of the first extraction signal by performing integration processing on the first extraction signal;

and extracting the first extraction signal according to the extraction factor of the first extraction signal, and reducing the sampling frequency of the first extraction signal through extraction processing.

3. The lock-in amplifier based harmonic extraction method according to claim 1, wherein the obtaining a second extracted signal after the first extracted signal passes through the CIC filter, and performing harmonic processing on the second extracted signal by an IIR filter comprises:

filtering out sine reference signals and cosine reference signals included in the second extraction signals through the IIR filter;

the passband of the IIR filter is widened, and stopband attenuation is reduced, so that the gas signal with strong spectral absorption in the second extraction signal is stable;

and narrowing the pass band of the IIR filter, and increasing the attenuation of the stop band, so that the gas signal with weak spectral absorption in the second extraction signal is easy to extract.

4. The harmonic extraction method based on the lock-in amplifier as claimed in claim 1, wherein the obtaining of the target extraction signal after the second extraction signal passes through the IIR filter, and the integrating of the target extraction signal through the orthogonalizer to obtain the harmonic of the signal wave comprises:

the phase of the target extraction signal is integrated through the orthogonal device, so that the phases of the signal wave passing through the orthogonal device and the input signal are independent;

extracting harmonic waves of signal waves containing spectral absorption information, and acquiring the gas concentration in the transformer oil according to the harmonic waves.

5. A lock-in amplifier based harmonic extraction system, comprising:

the signal input module is used for acquiring a signal wave containing spectral absorption information in the gas precipitated from the transformer oil, and taking the signal wave, a sine reference signal and a cosine reference signal as input signals according to the modulation frequency of the signal wave;

the first filtering module is used for obtaining a first extraction signal after the input signal passes through a multiplier, and then integrating and extracting the first extraction signal through a CIC filter;

the second filtering module is used for obtaining a second extraction signal after the first extraction signal passes through the CIC filter and carrying out harmonic processing on the second extraction signal through an IIR filter;

and the harmonic acquisition module is used for acquiring a target extraction signal after the second extraction signal passes through the IIR filter, and integrating the target extraction signal through an orthogonality device to acquire the harmonic of the signal wave.

6. The lock-in amplifier based harmonic extraction system of claim 5, wherein the first filtering module comprises an integral decimation unit configured to:

increasing the amplitude of the first extraction signal by performing integration processing on the first extraction signal;

7. The lock-in amplifier based harmonic extraction system of claim 6, wherein the second filtering module further comprises a noise filtering unit configured to:

filtering out sine reference signals and cosine reference signals included in the second extraction signals through the IIR filter;

the passband of the IIR filter is widened, and stopband attenuation is reduced, so that the gas signal with strong spectral absorption in the second extraction signal is stable;

8. The lock-in amplifier based harmonic extraction system of claim 5, wherein the harmonic acquisition module comprises a signal integration unit configured to:

extracting harmonic waves of signal waves containing spectral absorption information, and acquiring the gas concentration in the transformer oil according to the harmonic waves.

9. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the steps of the method of any of claims 1 to 4 are implemented when the computer program is executed by the processor.

10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 4.

Technical Field

The present application relates to the field of power equipment, and in particular, to a harmonic extraction method and apparatus based on a lock-in amplifier, a computer device, and a storage medium.

Background

At present, most transformers of domestic power systems adopt insulating oil for insulation and heat dissipation. With long-term operation, the insulating oil and the solid insulating material in the transformer are gradually aged under the action of temperature, electric field, oxidation and other factors, and a small amount of H2 and low molecular hydrocarbon gas such as CH4, C2H6, C2H4 and the like are generated. The accuracy and stability of measuring the concentration in the transformer oil will be directly related to the identification of the transformer fault. Currently, TDLAS is an effective way to measure gases.

The lock-in amplifier is a core of the TDLAS and is used for extracting useful harmonic signals which can be used for concentration calculation from weak absorption signals. The principle of the lock-in amplifier is the theory related to the signal. The reference signal of the phase-locked amplifier has the same frequency and phase with the input signal, and the noise component in the input signal has random phase and frequency, so that the noise component is independent of the reference signal and can be filtered. In order to improve the signal-to-noise ratio of the input signal, the sampling frequency of the signal and the laser modulation frequency are generally set higher. And too high sampling frequency can lead to large calculation amount during data demodulation, and reduce the real-time performance of detection.

Disclosure of Invention

In view of the above, it is necessary to provide a method, an apparatus, a device and a storage medium for harmonic extraction based on a lock-in amplifier.

In a first aspect, an embodiment of the present invention provides a harmonic extraction method based on a lock-in amplifier, where the method includes the following steps:

the input signal is processed by a multiplier to obtain a first extraction signal, and then the first extraction signal is integrated and extracted by a CIC filter;

obtaining a second extraction signal after the first extraction signal passes through the CIC filter, and carrying out harmonic processing on the second extraction signal through an IIR filter;

Further, the obtaining a first extraction signal by passing the input signal through a multiplier, and then integrating and extracting the first extraction signal through a CIC filter includes:

increasing the amplitude of the first extraction signal by performing integration processing on the first extraction signal;

Further, the obtaining a second extracted signal after the first extracted signal passes through the CIC filter, and performing harmonic processing on the second extracted signal through an IIR filter includes:

filtering out sine reference signals and cosine reference signals included in the second extraction signals through the IIR filter;

the passband of the IIR filter is widened, and stopband attenuation is reduced, so that the gas signal with strong spectral absorption in the second extraction signal is stable;

Further, the obtaining a target extraction signal after the second extraction signal passes through the IIR filter, and integrating the target extraction signal through an orthogonalizer to obtain a harmonic of the signal wave includes:

extracting harmonic waves of signal waves containing spectral absorption information, and acquiring the gas concentration in the transformer oil according to the harmonic waves.

On the other hand, the embodiment of the invention also provides a harmonic extraction system based on the lock-in amplifier, which comprises:

Further, the first filtering module includes an integral decimation unit, and the integral decimation unit is configured to:

increasing the amplitude of the first extraction signal by performing integration processing on the first extraction signal;

Further, the second filtering module further includes a noise filtering unit, and the noise filtering unit is configured to:

filtering out sine reference signals and cosine reference signals included in the second extraction signals through the IIR filter;

the passband of the IIR filter is widened, and stopband attenuation is reduced, so that the gas signal with strong spectral absorption in the second extraction signal is stable;

Further, the harmonic acquisition module includes a signal integration unit, and the signal integration unit is configured to:

extracting harmonic waves of signal waves containing spectral absorption information, and acquiring the gas concentration in the transformer oil according to the harmonic waves.

The embodiment of the present invention further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor, and when the processor executes the computer program, the following steps are implemented:

the input signal is processed by a multiplier to obtain a first extraction signal, and then the first extraction signal is integrated and extracted by a CIC filter;

obtaining a second extraction signal after the first extraction signal passes through the CIC filter, and carrying out harmonic processing on the second extraction signal through an IIR filter;

An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the following steps:

the input signal is processed by a multiplier to obtain a first extraction signal, and then the first extraction signal is integrated and extracted by a CIC filter;

obtaining a second extraction signal after the first extraction signal passes through the CIC filter, and carrying out harmonic processing on the second extraction signal through an IIR filter;

The harmonic extraction method, the harmonic extraction device, the computer equipment and the storage medium based on the lock-in amplifier comprise the following steps: acquiring a signal wave containing spectral absorption information in gas precipitated from transformer oil, and taking the signal wave, a sine reference signal and a cosine reference signal as input signals according to the modulation frequency of the signal wave; the input signal is processed by a multiplier to obtain a first extraction signal, and then the first extraction signal is integrated and extracted by a CIC filter; obtaining a second extraction signal after the first extraction signal passes through the CIC filter, and carrying out harmonic processing on the second extraction signal through an IIR filter; and obtaining a target extraction signal after the second extraction signal passes through the IIR filter, and integrating the target extraction signal through an orthogonalizer to obtain the harmonic wave of the signal wave. This application obtains the harmonic of signal wave and then obtains the calculation of carrying out gas concentration through combining factors such as interference killing feature, amplitude size, and this application is just enough through one-level CIC in obtaining the harmonic, need not half band filter and continues to fall the sampling, prevents to fall the low excessively that falls the sampling rate, leads to the useful information in the signal too little. Meanwhile, the CIC filter and the IIR filter are used together, the CIC down-sampling effect is fully utilized, the advantages of good filtering effect and small calculation amount of the IIR filter are utilized, different low-pass filters are arranged aiming at different gases dissolved in the transformer oil, the characteristics of the gases can be better utilized, the optimal demodulation effect is achieved, and therefore the gas concentration is calculated more accurately.

Drawings

FIG. 1 is a schematic flow chart of a harmonic extraction method based on a lock-in amplifier according to an embodiment;

FIG. 2 is a schematic diagram of a process for performing integration and decimation by a CIC filter in one embodiment;

FIG. 3 is a flow diagram illustrating filtering by an IIR filter in one embodiment;

FIG. 4 is a schematic diagram of a signal integration process for signal waves according to an embodiment;

FIG. 5 is a block diagram of a harmonic extraction system based on a lock-in amplifier in one embodiment;

FIG. 6 is a diagram illustrating an internal structure of a computer device according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In one embodiment, as shown in fig. 1, there is provided a harmonic extraction method based on a lock-in amplifier, comprising the steps of:

step 101, acquiring a signal wave containing spectral absorption information in gas precipitated from transformer oil, and taking the signal wave, a sine reference signal and a cosine reference signal as input signals according to the modulation frequency of the signal wave;

step 102, obtaining a first extraction signal after the input signal passes through a multiplier, and then integrating and extracting the first extraction signal through a CIC filter;

103, obtaining a second extraction signal after the first extraction signal passes through the CIC filter, and performing harmonic processing on the second extraction signal through an IIR filter;

and 104, obtaining a target extraction signal after the second extraction signal passes through the IIR filter, and integrating the target extraction signal through an orthogonalizer to obtain a harmonic wave of the signal wave.

Specifically, the embodiment acquires the harmonic wave of the signal wave by combining factors such as the anti-interference capability and the amplitude and then acquires the calculation of the gas concentration, wherein it is enough to pass through the first-stage CIC in acquiring the harmonic wave, and the half-band filter is not needed to continue down-sampling, so that the situation that the sampling rate is too low to cause too little useful information in the signal is prevented. The signal wave is a signal containing spectral absorption information obtained by superimposing a sawtooth wave and a sine wave, and if the laser modulation frequency is W, the frequencies of the sine and cosine reference signals are also set to the same frequency during demodulation. Meanwhile, the CIC filter and the IIR filter are used together, the CIC down-sampling effect is fully utilized, the advantages of good filtering effect and small calculation amount of the IIR filter are utilized, different low-pass filters are arranged aiming at different gases dissolved in the transformer oil, the characteristics of the gases can be better utilized, the optimal demodulation effect is achieved, and therefore the gas concentration is calculated more accurately.

Wherein, the TDLAS technology is used for measuring the concentration of the gas, and the potential hidden faults of the transformer are estimated according to the concentration of the gas. The TDLAS technique is a technique for calculating the component and state information of a gaseous substance by applying a tuning signal to a diode laser to scan the wavelength and obtain the absorption spectrum of the gaseous substance, and is widely applied to gas detection in the industrial and environmental fields. In the actual detection process, the peak-to-peak value of the gas absorption peak in the second harmonic is usually used as the basis for concentration calculation, and the first-order relationship between the peak-to-peak value and the concentration of the gas absorption peak in the second harmonic is calculated by introducing gas with known concentration into the white cell.

In one embodiment, as shown in fig. 2, the integrating and decimating by the CIC filter includes:

step 201, acquiring an integral length of the first extraction signal, and performing integral processing on the first extraction signal according to the integral length to reduce random noise of the first extraction signal;

step 202, increasing the amplitude of the first extraction signal by performing integration processing on the first extraction signal;

step 203, performing decimation on the first extraction signal according to the decimation factor of the first extraction signal, and reducing the sampling frequency of the first extraction signal through decimation processing.

Specifically, the CIC filter is divided into two steps of integration and decimation. Integration needs to determine an integration length R firstly, the influence of random noise in a signal can be reduced under the action of the integration, the amplitude of the signal is increased to a certain extent, the coefficient of peak-to-peak reverse concentration is reduced, and the stability of concentration detection is enhanced. The purpose of extraction is to reduce the sampling frequency, on one hand, reduce the number of data points and improve the calculation time, and on the other hand, a filter with a narrow passband can be arranged. And the required adopted signal is obtained after integration and extraction of the CIC filter respectively, so that subsequent further filtering and integration are facilitated.

In one embodiment, as shown in fig. 3, the flow of the filtering process performed by the IIR filter includes:

step 301, filtering out sine reference signals and cosine reference signals included in the second extraction signal through the IIR filter;

step 302, widening the passband of the IIR filter and reducing stopband attenuation, so that the gas signal with strong spectral absorption in the second extraction signal is stable;

and 303, narrowing the pass band of the IIR filter, and increasing the attenuation of the stop band, so that the gas signal with weak spectral absorption in the second extraction signal is easy to extract.

Specifically, after the signal passes through the CIC filter, the sampling frequency is reduced, and then the reference signal and the noise are filtered out by the low pass filter. The selection of the low-pass filter is directly related to the high quality of harmonic waves, and the high quality is realized by adopting an IIR filter, so that the large calculation amount of the FIR filter is avoided. For C2H4, CH4, C2H2 and CO2 with strong spectrum absorption in transformer oil, the passband of the low-pass filter can be properly widened, and the stopband attenuation can be properly reduced, so that the distortion of signals can be prevented. The passband of the filter for absorbing the C2H6 and CO gas with weak absorption is as narrow as possible, and the attenuation is as large as possible, so as to prevent the useful signal from being submerged by noise and being unable to be extracted.

In one embodiment, as shown in fig. 4, the process of signal integration of the signal wave includes:

step 401, integrating the phases of the target extraction signals through the orthogonalizer, so that the phases of the signal waves passing through the orthogonalizer and the input signals are independent of each other;

step 402 extracts harmonics of the signal waves containing spectral absorption information, and obtains the gas concentration in the transformer oil according to the harmonics.

In particular, the role of the quadrature device is to integrate the phase so that the demodulated harmonics are not affected by the input signal phase. The harmonic wave of the signal wave of the target gas is obtained after phase integration, and the concentration information of the gas is obtained according to the harmonic wave, so that different low-pass filters are arranged for different gases dissolved in the transformer oil, the characteristics of the gas can be better utilized, the optimal demodulation effect is achieved, and the gas concentration is calculated more accurately.

It should be understood that, although the steps in the above-described flowcharts are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least a portion of the steps in the above-described flowcharts may include multiple sub-steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of performing the sub-steps or the stages is not necessarily sequential, but may be performed alternately or alternatingly with other steps or at least a portion of the sub-steps or stages of other steps.

In one embodiment, as shown in fig. 5, there is provided a harmonic extraction system based on a lock-in amplifier, comprising:

the signal input module 501 is configured to acquire a signal wave containing spectral absorption information in gas precipitated from transformer oil, and use the signal wave, a sine reference signal and a cosine reference signal as input signals according to modulation frequency of the signal wave;

a first filtering module 502, configured to obtain a first extracted signal after the input signal passes through a multiplier, and then integrate and extract the first extracted signal through a CIC filter;

a second filtering module 503, configured to obtain a second extracted signal after the first extracted signal passes through the CIC filter, and perform harmonic processing on the second extracted signal through an IIR filter;

a harmonic obtaining module 504, configured to obtain a target extracted signal after the second extracted signal passes through the IIR filter, and integrate the target extracted signal through an orthogonalizer to obtain a harmonic of the signal wave.

In one embodiment, as shown in fig. 5, the first filtering module 502 includes an integral decimation unit 5021, and the integral decimation unit 5021 is configured to:

increasing the amplitude of the first extraction signal by performing integration processing on the first extraction signal;

In one embodiment, as shown in fig. 5, the second filtering module 503 further includes a noise filtering unit 5031, and the noise filtering unit 5031 is configured to:

filtering out sine reference signals and cosine reference signals included in the second extraction signals through the IIR filter;

the passband of the IIR filter is widened, and stopband attenuation is reduced, so that the gas signal with strong spectral absorption in the second extraction signal is stable;

In one embodiment, as shown in fig. 5, the harmonic acquisition module 504 includes a signal integration unit 5041, the signal integration unit 5041 is configured to:

extracting harmonic waves of signal waves containing spectral absorption information, and acquiring the gas concentration in the transformer oil according to the harmonic waves.

For specific limitations of the harmonic extraction system based on the lock-in amplifier, reference may be made to the above limitations of the harmonic extraction method based on the lock-in amplifier, which are not described herein again. The various modules in the above-described lock-in amplifier based harmonic extraction system may be implemented in whole or in part by software, hardware, and combinations thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

FIG. 6 is a diagram illustrating an internal structure of a computer device in one embodiment. As shown in fig. 6, the computer apparatus includes a processor, a memory, a network interface, an input device, and a display screen connected through a system bus. Wherein the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program that, when executed by the processor, causes the processor to implement a lock-in amplifier based harmonic extraction method. The internal memory may also have stored therein a computer program that, when executed by the processor, causes the processor to perform a method for harmonic extraction based on a lock-in amplifier. The display screen of the computer equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on the shell of the computer equipment, an external keyboard, a touch pad or a mouse and the like.

Those skilled in the art will appreciate that the architecture shown in fig. 6 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.

In one embodiment, a computer device is provided, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor implementing the following steps when executing the computer program:

the input signal is processed by a multiplier to obtain a first extraction signal, and then the first extraction signal is integrated and extracted by a CIC filter;

obtaining a second extraction signal after the first extraction signal passes through the CIC filter, and carrying out harmonic processing on the second extraction signal through an IIR filter;

In one embodiment, the processor, when executing the computer program, further performs the steps of:

increasing the amplitude of the first extraction signal by performing integration processing on the first extraction signal;

In one embodiment, the processor, when executing the computer program, further performs the steps of:

filtering out sine reference signals and cosine reference signals included in the second extraction signals through the IIR filter;

the passband of the IIR filter is widened, and stopband attenuation is reduced, so that the gas signal with strong spectral absorption in the second extraction signal is stable;

In one embodiment, the processor, when executing the computer program, further performs the steps of:

extracting harmonic waves of signal waves containing spectral absorption information, and acquiring the gas concentration in the transformer oil according to the harmonic waves.

In one embodiment, a computer-readable storage medium is provided, having a computer program stored thereon, which when executed by a processor, performs the steps of: