CN107271753A - Voltage flicker detection and device - Google Patents

Abstract

The invention provides a voltage flicker detection method and device. Applied to a digital flicker detector, the digital flicker detector stores a comparison table of amplitude modulation wave frequency and voltage fluctuation value, and the method includes: detecting voltage signals with multiple amplitude modulation wave frequencies to obtain multiple amplitude modulation wave frequency According to the dynamic vector method, the voltage signal of multiple amplitude modulation frequency is analyzed and calculated, and the voltage fluctuation value of multiple amplitude modulation frequency is obtained. According to the comparison table of amplitude modulation frequency and voltage fluctuation value, the voltage fluctuation value of multiple amplitude modulation frequency is calculated and processed, and the detection result of voltage flicker is obtained. Thus, the voltage flicker detection process is simplified, the calculation amount is small, the voltage flicker detection result can be obtained quickly, the detection efficiency and measurement accuracy are improved, and the detection error is reduced. It has a good prospect for engineering application and theoretical analysis.

Description

Voltage flicker detection method and device

technical field

The invention relates to the technical field of voltage detection, in particular to a voltage flicker detection method and device.

Background technique

New energy grid-connected power generation represented by wind power and photovoltaic power generation has become an irresistible development trend of new power systems. The output power of renewable energy such as solar energy and wind energy has strong fluctuations, which may easily cause voltage fluctuations and flicker at the public connection point of the power grid. The voltage flicker phenomenon will cause harm to people's life and work. The flickering of the lighting source will cause people's visual fatigue and damage people's eyes. Voltage flicker affects the normal operation of the motor and affects the work efficiency of the enterprise.

At present, the commonly used voltage fluctuation detection methods in the world mainly include square detection method, rectification detection method and effective value detection method. The digital realization of the rectification detection method and the effective value detection method is relatively difficult, and it cannot effectively detect the abrupt and non-stationary voltage flicker envelope signal.

In my country, the voltage flicker detection generally adopts the square detection method recommended by IEC. The square detection method recommended by IEC is stipulated in an analog way. There is no clear implementation method for each link, and the actual numerical calculation cannot be performed. The application needs to be based on IEC flicker The measurement principle is to design the digital filter of each link.

In the prior art, a digital flicker meter is often used for numerical calculation, but the calculation process is cumbersome and the measurement error is relatively large.

Contents of the invention

In order to overcome the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a voltage flicker detection method and device, which simplifies the voltage flicker detection process, has a small amount of calculation, and can quickly obtain the voltage flicker detection result , improve the detection efficiency and reduce the detection error.

The first object of the present invention is to provide a voltage flicker detection method, which is applied to a digital flicker detector, wherein a comparison table of amplitude modulation wave frequency and voltage fluctuation value is stored in the digital flicker detector, and the method include:

Detecting the voltage signal of multiple AM wave frequencies to obtain the voltage signal of multiple AM wave frequencies, analyzing and calculating the voltage signal of multiple AM wave frequencies according to the dynamic vector method, and obtaining the voltage fluctuation value of multiple AM wave frequencies;

The voltage fluctuation values of the multiple amplitude modulation frequencies are calculated and processed according to the comparison table of the amplitude modulation frequency and the voltage fluctuation value, and a voltage flicker detection result is obtained.

The second object of the present invention is a voltage flicker detection device, which is applied to a digital flicker detector. The digital flicker detector stores a comparison table of amplitude modulation frequency and voltage fluctuation value, and the device includes :

The detection and calculation module is used to detect the voltage signal of multiple AM wave frequencies to obtain the voltage signal of multiple AM wave frequencies, analyze and calculate the voltage signal of multiple AM wave frequencies according to the dynamic vector method, and obtain the voltage fluctuation of multiple AM wave frequencies value;

The calculation processing module is used to calculate and process the voltage fluctuation value of the multiple amplitude modulation frequency according to the comparison table of the amplitude modulation frequency and the voltage fluctuation value, and obtain the voltage flicker detection result.

Compared with the prior art, the present invention has the following beneficial effects:

The invention provides a voltage flicker detection method and device. Applied to a digital flicker detector, the digital flicker detector stores a comparison table of amplitude modulation wave frequency and voltage fluctuation value, and the method includes: detecting voltage signals with multiple amplitude modulation wave frequencies to obtain multiple amplitude modulation wave frequency According to the dynamic vector method, the voltage signal of multiple amplitude modulation frequency is analyzed and calculated, and the voltage fluctuation value of multiple amplitude modulation frequency is obtained. The voltage fluctuation values of the multiple amplitude modulation frequencies are calculated and processed according to the comparison table of the amplitude modulation frequency and the voltage fluctuation value, and a voltage flicker detection result is obtained. Therefore, the voltage flicker detection process is simplified, the calculation amount is small, the voltage flicker detection result can be obtained quickly, the detection efficiency and measurement accuracy are improved, and the detection error is reduced. It has a good prospect for engineering application and theoretical analysis.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 is a schematic block diagram of a digital flicker detector provided by a preferred embodiment of the present invention.

Fig. 2 is one of the flow charts of the steps of the method for detecting voltage flicker provided by the first embodiment of the present invention.

Fig. 3 is the second flowchart of steps of the method for detecting voltage flicker provided by the first embodiment of the present invention.

FIG. 4 is a flowchart of substeps of step S110 shown in FIG. 3 provided by the first embodiment of the present invention.

FIG. 5 is a sub-step flowchart of sub-step S111 shown in FIG. 4 provided by the first embodiment of the present invention.

FIG. 6 is a flow chart of sub-steps of step S120 shown in FIG. 2 provided by the first embodiment of the present invention.

FIG. 7 is a flow chart of sub-steps of step S130 shown in FIG. 2 provided by the first embodiment of the present invention.

FIG. 8 is a functional block diagram of a voltage flicker detection device provided by a second embodiment of the present invention.

Icons: 100-digital flicker detector; 110-memory; 120-processor; 200-voltage flicker detection device; 210-detection calculation module; 220-calculation processing module.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some of the embodiments of the present invention, but not all of them. The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations. Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

It should be noted that like numerals and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures. In addition, the terms "first", "second", etc. are only used for distinguishing descriptions, and should not be construed as indicating or implying relative importance.

Please refer to FIG. 1 . FIG. 1 is a schematic block diagram of a digital flicker detector 100 provided by a preferred embodiment of the present invention. The digital flicker detector 100 includes a memory 110 , a voltage flicker detection device 200 and a processor 120 .

The memory 110 and the processor 120 are electrically connected to each other directly or indirectly to realize data transmission or interaction. For example, these components may be electrically connected to each other through one or more communication buses or signal lines. A voltage flicker detection device 200 is stored in the memory 110, and the voltage flicker detection device 200 includes at least one software function module that can be stored in the memory 110 in the form of software or firmware (firmware), and the processor 120 passes The software programs and modules stored in the memory 110 are executed to perform various functional applications and data processing.

Wherein, the memory 110 may be, but not limited to, random access memory (Random Access Memory, RAM), read-only memory (Read Only Memory, ROM), programmable read-only memory (Programmable Read-Only Memory, PROM), which can Erasable Programmable Read-Only Memory (EPROM), Electric Erasable Programmable Read-Only Memory (EEPROM), etc. Wherein, the memory 110 is used to store a program, and the processor 120 executes the program after receiving an execution instruction. Further, the software programs and modules in the memory 110 may also include an operating system, which may include various software components and/or drivers for managing system tasks (such as memory management, storage device control, power management, etc.), and It can communicate with various hardware or software components to provide an operating environment for other software components.

The processor 120 may be an integrated circuit chip and has a signal processing capability. The aforementioned processor 120 may be a general processor, including a central processing unit (Central Processing Unit, CPU), a network processor (Network Processor, NP), and the like. Various methods, steps and logic block diagrams disclosed in the embodiments of the present invention may be implemented or executed. A general-purpose processor may be a microprocessor, or the processor may be any conventional processor, and the like.

It can be understood that the structure shown in FIG. 1 is only for illustration, and the digital flicker detector 100 may also include more or less components than those shown in FIG. 1 , or have a configuration different from that shown in FIG. 1 . Each component shown in Fig. 1 may be implemented by hardware, software or a combination thereof.

first embodiment

Please refer to FIG. 2 . FIG. 2 is one of the flowcharts of the steps of the voltage flicker detection method provided by the first embodiment of the present invention. The method is applied to the digital flicker detector 100, and the digital flicker detector 100 stores a comparison table of amplitude modulation wave frequency and voltage fluctuation value. The specific flow of the voltage flicker detection method will be described in detail below.

Step S120, detecting the voltage signal of multiple AM frequency to obtain the voltage signal of multiple AM frequency, analyzing and calculating the voltage signal of multiple AM frequency according to the dynamic vector method, and obtaining the voltage fluctuation value of multiple AM frequency.

Step S130 , according to the comparison table of the amplitude modulation wave frequency and the voltage fluctuation value, calculate and process the voltage fluctuation values of the multiple amplitude modulation wave frequencies to obtain a voltage flicker detection result.

Please refer to FIG. 3 . FIG. 3 is the second flowchart of steps of the method for detecting voltage flicker provided by the first embodiment of the present invention. The method also includes:

Step S110 , detecting a plurality of voltage signals with different single AM wave frequencies to obtain corresponding voltage signals, analyzing and calculating the voltage signals according to the dynamic vector method, and obtaining a comparison table of AM wave frequencies and voltage fluctuation values.

In this embodiment, in order to establish a comparison table between the AM frequency and the voltage fluctuation value, it is necessary to perform multiple detections of the voltage signal of a single AM frequency for multiple different AM frequencies.

Please refer to FIG. 4 . FIG. 4 is a flowchart of substeps of step S110 shown in FIG. 3 provided by the first embodiment of the present invention. The step S110 includes a sub-step S111 and a sub-step S112.

In sub-step S111, the voltage signal of each single AM wave frequency is detected to obtain the corresponding voltage signal, and the voltage signal is analyzed and calculated according to the dynamic vector method to obtain the contrast relationship between the AM wave frequency and the voltage fluctuation value.

Please refer to FIG. 5 . FIG. 5 is a sub-step flowchart of sub-step S111 shown in FIG. 4 provided by the first embodiment of the present invention. The sub-step S111 includes sub-step S1110, sub-step S1111 and sub-step S1112.

Sub-step S1110, when detecting the voltage signal of a single AM wave frequency each time, collect the voltage signal of the currently detected AM wave frequency within a preset period according to the preset sampling time interval, and perform the collected voltage signal The root mean square value is calculated to obtain the root mean square series.

In this embodiment, the collected voltage signal is a voltage signal collected at a new energy grid-connected location, and the new energy grid-connected location refers to a location where photovoltaic or wind power is connected to the grid.

In this embodiment, the digital flicker detector 100 collects the voltage signal of the currently detected AM wave frequency within a preset period (for example, 10s) according to a preset sampling time interval (for example, 20ms), and Perform preliminary processing on each collected voltage signal to obtain the instantaneous value of the voltage signal:

u(t)＝A(1+mcos2πf _m )cos2πf _s t

The digital flicker detector 100 calculates the root mean square value (RMS, Root MeanSquare) of the instantaneous value of the voltage signal to obtain the root mean square sequence (for example, y(t)), and the expression of the root mean square sequence y(t) is as follows:

Among them, A is the amplitude of the power frequency carrier voltage, f _s is the frequency of the power frequency carrier voltage, f _s =50Hz, m is the relative amplitude of the amplitude modulation wave voltage. f _m is the frequency of the amplitude modulation wave voltage, T=0.02s,

In this embodiment, root mean square (RMS), also known as root mean square, is the most common mathematical method for defining the effective voltage or current of alternating current (Alternating Current, AC). The order of calculation is square first, then average, and finally square root.

Sub-step S1111, perform Fourier transform on the root-mean-square sequence according to the dynamic vector method to obtain a dynamic vector.

In this embodiment, the digital flicker detector 100 uses the dynamic vector method to obtain the result of the root-mean-square sequence y(t) undergoing Fourier transform, and obtains the K-th value of y(t) after Fourier transform. The secondary output value, that is, the kth order dynamic vector of y(t), the expression is as follows:

Among them, according to the sampling time interval is 20ms, the preset period is T ₀ =10s, it can be obtained The frequency resolution is 0.1HZ, that is, the fundamental frequency after Fourier transform is 0.1Hz.

In sub-step S1112, the dynamic vector is brought into a preset formula for calculation, and the voltage fluctuation value corresponding to the frequency of the AM wave is obtained.

In this embodiment, the digital flicker detector 100 brings the dynamic vector into the preset formula for calculation, and can obtain the instantaneous flicker severity index S= The RMS voltage fluctuation value ΔU _rms of 1. Among them, the subjective visual response of illuminance fluctuations caused by voltage fluctuations is called instantaneous flicker visual sensitivity. Usually, the flicker detection rate is 50% as the measurement unit of instantaneous flicker visual sensitivity, that is, instantaneous flicker visual sensitivity S=1.

In this embodiment, the preset formula may be the relative value of the frequency amplitude obtained by using the DC component (0-order dynamic vector) as a reference value, wherein the relative value of the frequency amplitude is the current detected single amplitude modulation wave Under frequency, make half of the RMS fluctuation value ΔU _rms corresponding to S=1. Calculated as follows:

Among them, w _mi =2πf _i is the angular frequency of the i-th AM wave, and the denominator <y> ₀ represents the 0th-order dynamic vector, that is, the DC component of y(t) after Fourier transform. The fi in <y> _fi/0.1 represents the flicker frequency after Fourier transform, since the fundamental frequency is 0.1Hz, that is, <y> _k =<y> _fi/0.1 .

In this embodiment, by calculating the formulas on the left and right sides of the first equal sign in the above formula, the relative value of the frequency amplitude can be obtained B _fi can be obtained by multiplying the relative value of the frequency amplitude by 2, and B _fi is the RMS voltage fluctuation value (ie, _{ΔU rms} ) that makes S=1 when the frequency of the AM wave is fi. In this way, the comparison relationship between the current AM wave frequency and the voltage fluctuation value can be obtained.

In this embodiment, this scheme uses the dynamic vector method to analyze the voltage flicker of new energy grid-connected, and gives a specific analytical expression, which provides a new direction for the study of digital flicker detection.

Sub-step S112 , generating and storing a comparison table of AM wave frequency and voltage fluctuation value according to the obtained correspondence between multiple AM wave frequencies and voltage fluctuation values.

In this embodiment, the digital flicker detector 100 generates and stores a comparison table of AM wave frequency and voltage fluctuation value according to the obtained correspondence between multiple AM wave frequencies and voltage fluctuation values. Based on the above description, the comparison table of AM frequency and voltage fluctuation value may be a comparison table of AM frequency (f) and RMS voltage fluctuation value (ΔU _rms ).

In this embodiment, since human eyes can only perceive voltage fluctuations within 0.05-35 Hz, direct current and frequencies above 35 Hz do not need to be recorded in the table.

Step S120 in FIG. 2 will be described below based on the above description.

Please refer to FIG. 6 . FIG. 6 is a flowchart of substeps of step S120 shown in FIG. 2 provided by the first embodiment of the present invention. The step S120 includes a sub-step S121 and a sub-step S122.

Sub-step S121, collecting voltage signals of multiple AM wave frequencies, performing modulation conversion on the collected voltage signals of multiple AM wave frequencies, and calculating the root mean square value of the modulated converted voltage signals to obtain the root mean square sequence of multiple AM wave frequencies.

In this embodiment, the digital flicker detector 100 collects voltage signals with multiple amplitude modulation wave frequencies at the new energy grid-connected place, and modulates and converts the voltage signals into voltages in the form of sinusoidal multiple amplitude modulation waves signal, the formula is as follows:

Among them, U is the amplitude of the power frequency carrier voltage, K is the total number of AM waves, mi is the relative amplitude of the _i -th AM wave, f _i is the frequency of the i-th AM wave, and f _sys is the power frequency The frequency of the carrier voltage.

In this embodiment, the operation of calculating the root-mean-square value of the modulated and converted voltage signal to obtain the root-mean-square sequence of multiple AM wave frequencies is the same as the operation at a single AM wave frequency. For details, please refer to the above sub-step S1110. related description.

In sub-step S122, the root-mean-square sequence of the multi-amplitude frequency is calculated and processed according to the dynamic vector method to obtain the voltage fluctuation value of the multi-amplitude frequency.

In this embodiment, the digital flicker detector 100 calculates and processes the root-mean-square sequence of the multi-amplitude frequency according to the dynamic vector method, and obtains the voltage fluctuation value (A _fi ) of the multi-amplitude frequency, wherein, The operation of processing the root-mean-square sequence of multiple AM frequencies according to the dynamic vector method is the same as the operation at a single AM frequency. For details, please refer to the relevant descriptions of sub-step S1111 and sub-step S1112 above.

Step S130 in FIG. 2 will be described below based on the above description.

Please refer to FIG. 7 . FIG. 7 is a flow chart of sub-steps of step S130 shown in FIG. 2 provided by the first embodiment of the present invention. The step S130 includes a sub-step S131 and a sub-step S132.

Sub-step S131 , according to the comparison table of AM wave frequency and voltage fluctuation value, calculate the voltage fluctuation value of multiple AM wave frequencies, and obtain the instantaneous flicker value corresponding to each AM wave frequency.

In this embodiment, the digital flicker detector 100 obtains the voltage fluctuation value (B _fi ) corresponding to each AM wave frequency by querying a pre-stored comparison table of AM wave frequency and voltage fluctuation value. The digital flicker detector 100 brings each voltage fluctuation value (B _fi ) and the voltage fluctuation value (A _fi ) of multiple amplitude modulation waves obtained from the query into the preset flicker value formula for calculation, and obtains the corresponding The instantaneous flicker value (S _fi ). The specific formula is as follows:

Among them, S _fi refers to the instantaneous flicker value when the frequency of the AM wave is the _fi component.

In this embodiment, the frequency of the AM wave within the frequency range of the human eye's maximum perception of voltage flicker (the frequency of the AM wave between 0.05 and 35 Hz) can be obtained by querying the comparison between the frequency of the AM wave and the voltage fluctuation value. The voltage fluctuation value (B _fi ) corresponding to each AM wave frequency is obtained from the table. Therefore, the instantaneous flicker value (S _fi ) can be quickly calculated, and the detection speed can be accelerated.

In this embodiment, when performing multiple amplitude modulation frequency voltage flicker detection, the data in the comparison table of amplitude modulation frequency and voltage fluctuation value obtained by using the dynamic vector method in the above step S110 can be directly used for analysis and calculation, which speeds up The detection speed reduces the harm caused by the voltage flicker, reduces the error of the voltage flicker detection algorithm, and improves the measurement accuracy of the voltage flicker.

In sub-step S132, the summation and root calculation are performed on the multiple instantaneous flicker values to obtain the short-term flicker value.

In this embodiment, the digital flicker detector 100 can sum a plurality of instantaneous flicker values (S _fi ) to obtain a total instantaneous flicker value (S), and the summation formula is as follows:

The digital flicker detector 100 performs root calculation on the total instantaneous flicker value (S) to obtain the short-term flicker value (P _st ). For periodic stable voltage fluctuations, the calculation formula for short-term flicker value is as follows:

In this embodiment, this scheme applies the dynamic vector to the grid voltage flicker monitoring and analysis, which breaks through the limitation of the quasi-steady state assumption and considers the dynamic change of the phasor amplitude. The traditional vector method has a small amount of calculation and physical The concept is clear, and to a certain extent, it takes into account the accuracy of electromagnetic transient calculations.

second embodiment

Please refer to FIG. 8 , which is a functional block diagram of a voltage flicker detection device 200 according to a second embodiment of the present invention. The voltage flicker detection device 200 is applied to the digital flicker detector 100 . The device includes: a detection calculation module 210 and a calculation processing module 220 .

The detection calculation module 210 is used to detect the voltage signal of multiple AM wave frequencies to obtain the voltage signal of multiple AM wave frequencies, analyze and calculate the voltage signal of multiple AM wave frequencies according to the dynamic vector method, and obtain the voltage signal of multiple AM wave frequencies fluctuation value.

In this embodiment, the detection calculation module 210 is configured to execute step S120 in FIG. 2 . For a specific description of the detection calculation module 210 , reference may be made to the description of step S120 in FIG. 2 .

The calculation processing module 220 is configured to calculate and process the voltage fluctuation values of the multiple amplitude modulation frequency frequencies according to the comparison table of the amplitude modulation frequency and the voltage fluctuation value, so as to obtain a voltage flicker detection result.

In this embodiment, the calculation processing module 220 is configured to execute step S130 in FIG. 2 . For a specific description of the calculation processing module 220 , reference may be made to the description of step S130 in FIG. 2 .

The detection and calculation module 210 is also used to detect a plurality of different voltage signals of a single amplitude modulation wave frequency to obtain corresponding voltage signals, analyze and calculate the voltage signals according to the dynamic vector method, and obtain amplitude modulation frequency and voltage fluctuation values comparison table.

In this embodiment, the detection and calculation module 210 is further configured to execute step S110 in FIG. 3 . For a specific description of the detection and calculation module 210 , reference may also be made to the description of step S110 in FIG. 3 .

To sum up, the present invention provides a voltage flicker detection method and device. Applied to a digital flicker detector, the digital flicker detector stores a comparison table of amplitude modulation wave frequency and voltage fluctuation value, and the method includes: detecting voltage signals with multiple amplitude modulation wave frequencies to obtain multiple amplitude modulation wave frequency According to the dynamic vector method, the voltage signal of multiple amplitude modulation frequency is analyzed and calculated, and the voltage fluctuation value of multiple amplitude modulation frequency is obtained. The voltage fluctuation values of the multiple amplitude modulation frequencies are calculated and processed according to the comparison table of the amplitude modulation frequency and the voltage fluctuation value, and a voltage flicker detection result is obtained.

Therefore, the voltage flicker detection process is simplified, the calculation amount is small, the voltage flicker detection result can be obtained quickly, the detection efficiency and measurement accuracy are improved, and the detection error is reduced. It has a good prospect for engineering application and theoretical analysis.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A voltage flicker detection method, applied to a digital flicker detector, is characterized in that, a comparison table of amplitude modulation wave frequency and voltage fluctuation value is stored in the digital flicker detector, and the method comprises: Detecting the voltage signal of multiple AM wave frequencies to obtain the voltage signal of multiple AM wave frequencies, analyzing and calculating the voltage signal of multiple AM wave frequencies according to the dynamic vector method, and obtaining the voltage fluctuation value of multiple AM wave frequencies; The voltage fluctuation values of the multiple amplitude modulation frequencies are calculated and processed according to the comparison table of the amplitude modulation frequency and the voltage fluctuation value, and a voltage flicker detection result is obtained. 2. The method according to claim 1, characterized in that the method further comprises: Detect multiple voltage signals of different single AM wave frequency to obtain the corresponding voltage signal, analyze and calculate the voltage signal according to the dynamic vector method, and obtain the comparison table of AM wave frequency and voltage fluctuation value. 3. The method according to claim 2, characterized in that, the described voltage signals of a plurality of different single amplitude modulation wave frequencies are detected to obtain corresponding voltage signals, and the voltage signals are analyzed and calculated according to the dynamic vector method to obtain The steps of the comparison table of AM wave frequency and voltage fluctuation value include: Detecting the voltage signal of each single amplitude modulation wave frequency respectively to obtain the corresponding voltage signal, analyzing and calculating the voltage signal according to the dynamic vector method to obtain the contrast relationship between the amplitude modulation wave frequency and the voltage fluctuation value; A comparison table of amplitude modulation frequency and voltage fluctuation value is generated and stored according to the obtained correspondence between multiple amplitude modulation wave frequencies and voltage fluctuation values. 4. The method according to claim 3, wherein the voltage signal of each single AM wave frequency is detected respectively to obtain a corresponding voltage signal, and the voltage signal is analyzed and calculated according to the dynamic vector method, The steps for obtaining the contrast relationship between the amplitude modulation wave frequency and the voltage fluctuation value include: Each time a voltage signal of a single AM wave frequency is detected, the voltage signal of the currently detected AM wave frequency is collected within a preset period according to the preset sampling time interval, and the root mean square value of the collected voltage signal is calculated to obtain RMS series; Carry out Fourier transform to described root-mean-square sequence according to dynamic vector method, obtain dynamic vector; The dynamic vector is brought into a preset formula for calculation to obtain the voltage fluctuation value corresponding to the frequency of the AM wave. 5. The method according to claim 4, characterized in that, the voltage signal of multiple amplitude modulation frequency is detected, and the voltage signal of multiple amplitude modulation frequency is obtained, and the voltage signal of multiple amplitude modulation frequency is carried out according to the dynamic vector method Analyzing and calculating, the steps of obtaining the voltage fluctuation value of multiple AM wave frequencies include: Acquiring voltage signals of multiple AM wave frequencies, performing modulation conversion on the collected voltage signals of multiple AM wave frequencies, and calculating the root mean square value of the modulated converted voltage signals to obtain the root mean square sequence of multiple AM wave frequencies; The root-mean-square sequence of the multi-amplitude frequency is calculated and processed according to the dynamic vector method to obtain the voltage fluctuation value of the multi-amplitude frequency. 6. according to the described method of claim 1 or 5, it is characterized in that, according to the comparison table of amplitude modulation wave frequency and voltage fluctuation value, the voltage fluctuation value of multiple amplitude modulation wave frequencies is calculated and processed, and the voltage flicker detection result is obtained Steps include: According to the comparison table of AM wave frequency and voltage fluctuation value, the voltage fluctuation value of multiple AM wave frequencies is calculated, and the instantaneous flicker value corresponding to each AM wave frequency is obtained; The summation and root calculation of multiple instantaneous flicker values are carried out to obtain the short-term flicker value. 7. The method according to claim 6, characterized in that, the progressive calculation of the voltage fluctuation values of multiple AM frequency frequencies according to the comparison table of AM wave frequencies and voltage fluctuation values obtains the instantaneous flicker corresponding to each AM wave frequency Value steps include: Query the comparison table of AM wave frequency and voltage fluctuation value, and obtain the voltage fluctuation value corresponding to each AM wave frequency; Bring each voltage fluctuation value obtained from the query and the voltage fluctuation value of multiple AM wave frequencies into the preset flicker value formula for calculation, and obtain the corresponding instantaneous flicker value. 8. A voltage flicker detection device, which is applied to a digital flicker detector, is characterized in that, a comparison table of amplitude modulation frequency and voltage fluctuation value is stored in the digital flicker detector, and the device includes: The detection and calculation module is used to detect the voltage signal of multiple AM wave frequencies to obtain the voltage signal of multiple AM wave frequencies, analyze and calculate the voltage signal of multiple AM wave frequencies according to the dynamic vector method, and obtain the voltage fluctuation of multiple AM wave frequencies value; The calculation processing module is used to calculate and process the voltage fluctuation values of the multiple amplitude modulation frequency according to the comparison table of the amplitude modulation frequency and the voltage fluctuation value, so as to obtain the voltage flicker detection result. 9. The device according to claim 8, characterized in that: The detection and calculation module is also used to detect a plurality of different voltage signals of a single amplitude modulation wave frequency to obtain corresponding voltage signals, analyze and calculate the voltage signals according to the dynamic vector method, and obtain the frequency of the amplitude modulation wave and the voltage fluctuation value Chart. 10. The device according to claim 8, characterized in that, the calculation processing module calculates and processes the voltage fluctuation values of multiple amplitude modulation frequency frequencies according to the comparison table of amplitude modulation frequency and voltage fluctuation value, and obtains the voltage flicker detection result Ways include: According to the comparison table of AM wave frequency and voltage fluctuation value, the voltage fluctuation value of multiple AM wave frequencies is calculated, and the instantaneous flicker value corresponding to each AM wave frequency is obtained; The summation and root calculation of multiple instantaneous flicker values are carried out to obtain the short-term flicker value.