CN117471146A - Phase-locked closed-loop control method, device, equipment and medium for optical fiber current transformer - Google Patents
Phase-locked closed-loop control method, device, equipment and medium for optical fiber current transformer Download PDFInfo
- Publication number
- CN117471146A CN117471146A CN202311415719.7A CN202311415719A CN117471146A CN 117471146 A CN117471146 A CN 117471146A CN 202311415719 A CN202311415719 A CN 202311415719A CN 117471146 A CN117471146 A CN 117471146A
- Authority
- CN
- China
- Prior art keywords
- modulation
- phase
- signal
- sine wave
- optical fiber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 51
- 238000000034 method Methods 0.000 title claims abstract description 45
- 238000005070 sampling Methods 0.000 claims abstract description 28
- 238000012545 processing Methods 0.000 claims abstract description 14
- 230000003287 optical effect Effects 0.000 claims description 27
- 230000006870 function Effects 0.000 claims description 14
- 238000004590 computer program Methods 0.000 claims description 8
- 230000007704 transition Effects 0.000 claims description 8
- 238000003860 storage Methods 0.000 claims description 7
- 238000004364 calculation method Methods 0.000 claims description 5
- 238000001914 filtration Methods 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 4
- 238000011896 sensitive detection Methods 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 230000009471 action Effects 0.000 claims description 2
- 239000000835 fiber Substances 0.000 claims 1
- 238000005259 measurement Methods 0.000 description 9
- 230000010363 phase shift Effects 0.000 description 6
- 230000035945 sensitivity Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 230000004044 response Effects 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000010287 polarization Effects 0.000 description 3
- 238000003491 array Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000005658 nuclear physics Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/24—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices
- G01R15/247—Details of the circuitry or construction of devices covered by G01R15/241 - G01R15/246
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Gyroscopes (AREA)
Abstract
The invention relates to the technical field of optical fiber sensing, in particular to a phase-locked closed-loop control method, a device, equipment and a medium for an optical fiber current transformer, wherein the method comprises the following steps: forming an interference light path signal after the modulation of the electric signal, converting the interference light path signal into a sensing electric signal, and sending the sensing electric signal into an analog-to-digital converter for digital sampling; for a pair ofmWith a modulation periodTProcessing the sensing electric signal of (2) and processingmTDemodulating the sampling value in time to obtain a modulation depth error and a feedback phase error; generating a sine wave according to the modulation depth error; for a pair ofNWith a modulation periodTGenerates a sawtooth wave, whereinN=nm，nIs a positive integer; superposing the generated sine wave and sawtooth wave, and providing the superposed sine wave and sawtooth wave for a digital-to-analog converter to form a modulation signal; the modulating signal is converted into an electric signal through a digital-to-analog converter, so that the closed-loop control of the optical fiber current transformer is realized. In the present inventionThe measuring precision and the dynamic range of the optical fiber current transformer are improved, and the product cost is reduced.
Description
Technical Field
The invention relates to the technical field of optical fiber sensing, in particular to a phase-locked closed-loop control method, a phase-locked closed-loop control device, phase-locked closed-loop control equipment and a phase-locked closed-loop control medium for an optical fiber current transformer.
Background
The optical fiber current transformer adopts an all-optical fiber light path structure, and an optical fiber is used as an optical transmission medium and an optical sensor of a sensitive element, has the advantages of insulation, simple structure, high measurement precision, high response speed, strong electromagnetic interference resistance and the like, and has been widely applied to the fields of electric power, metallurgy and nuclear physics.
The principle of the optical fiber current transformer is as follows: light emitted by a light source is polarized by a polarizer to become linear polarized light, enters the fast axis and the slow axis of a polarization maintaining optical fiber through the melting point of the 45-degree optical fiber, is modulated by a phase modulator and then is transmitted along the polarization maintaining delay optical fiber, and is changed into two circular polarized lights with orthogonal rotation directions by a 1/4 wave plate, faraday phase shift is generated between the two circular polarized lights under the action of measured current, the two circular polarized lights return along an original path after passing through the end reflector of a sensitive optical fiber, the current phase difference is doubled, and the orthogonal linear polarized lights finally pass through the polarizer for polarization detection and interference after returning again through the original optical path.
The optical fiber current transformer can adopt an open loop scheme and a closed loop scheme according to different signal detection methods. The closed-loop optical fiber current transformer generally adopts superposition of square waves and ladder waves as modulation signals, the square waves are used for bias modulation, the ladder waves are used for feedback modulation, the measurement precision and the dynamic range of the transformer system are effectively improved, but the scheme has higher requirements on the device selection, modulation and demodulation bandwidths of the transformer, and the cost is higher.
The open-loop optical fiber current transformer generally adopts sine waves as modulation signals, has simple working principle and easy realization, has low requirement on working bandwidth by sine wave modulation signals and lower equipment cost, but only has an open-loop demodulation scheme at present, needs to calculate an arctangent function, has lower sensitivity and small dynamic range, and can only be used in occasions with low requirements on measurement precision and measurement range.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Disclosure of Invention
The invention provides a phase-locked closed-loop control method, a device, equipment and a medium for an optical fiber current transformer, thereby effectively solving the problems in the background technology.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a phase-locked closed-loop control method for an optical fiber current transformer comprises the following steps:
an input optical signal entering a modulator in the optical fiber current transformer forms an interference optical path signal after the modulation effect of an electric signal, and the interference optical path signal is converted into a sensing electric signal which is sent to an analog-to-digital converter for digital sampling;
digital sampling is carried out on the sensing electric signals of m modulation periods T, and sampling values in mT time are demodulated to obtain modulation depth errors and feedback phase errors;
generating a sine wave according to the modulation depth error;
generating a sawtooth wave by processing the feedback phase errors of N modulation periods T, wherein N=nm and N is a positive integer;
superposing the generated sine wave and saw tooth wave, and providing the superposition to a digital-to-analog converter to form a modulation signal;
the modulating signal is converted into an electric signal through a digital-to-analog converter, and closed-loop control of the optical fiber current transformer is realized by utilizing the electric signal.
Further, the converting the interference optical path signal into a sensing electric signal and sending the sensing electric signal to an analog-to-digital converter for digital sampling includes:
converting the interference light path signal into a sensing electric signal through a photoelectric detector;
the sensing electric signal enters an analog-to-digital converter through a pre-amplifying circuit.
Further, the demodulating the sampling value in the mT time includes the following steps:
based on a digital phase-sensitive detection method, carrying out digital demodulation processing on the interference light path signal sampling values of m modulation periods T, and respectively taking the amplitudes H of first harmonic, second harmonic and fourth harmonic 1i 、H 2i And H 4i ；
Based on the ratio of the Bessel function of two and four ordersAnd modulation depth->Correspondence, combining two-four harmonic ratio +.> Calculate modulation depth +.>
Calculating a feedback phase error according to a formulaThe calculation formula is as follows:
further, the generating a sine wave according to the modulation depth error includes the following steps:
setting a sine wave period which is a modulation period T, and setting sine wave amplitude values to adjust every interval mT;
according to modulation depthCalculating the modulation depth error->Wherein->Modulating depth for a target;
according to the modulation depth errorCalculating sine wave amplitude error +.>Where k is the sine wave amplitude gain factor.
Further, the feedback phase error processing for the N modulation periods T generates a sawtooth wave, which includes the following steps:
setting the sawtooth wave period as N modulation periods T, and setting the sawtooth wave amplitude value to be adjusted at intervals NT;
according to the feedback phase errorCalculating feedback phase offset +.>
Based on the feedback phase offsetCalculating saw-tooth amplitude error +.>Where h is the saw tooth amplitude gain factor.
Further, the calculating feedback phase offsetThe method comprises the following steps:
feedback of phase error with demodulation values in m modulation periods TAs basic unit, analyzing the sampled values of N modulation periods T, and calculating to obtain N feedback phase errors +.>
Because of sawtooth voltage jump during sawtooth wave switching, j feedback phase errors are generated within the transition time tau after the jumpWherein j= [ τ/mT ]]，[]Representing the upward rounding from n feedback phase errors +.>J pieces of saw-tooth wave voltage jump post transition time tau are removed;
again for the remaining (n-j) feedback phase errorsFiltering to remove maximum value +.>And minimum->The feedback phase offset is:
further, the modulating signal after superimposing the sine wave and the sawtooth wave includes:
where sawroot () represents a magnitude of 1, with mnT as the period,for the sawtooth voltage signal of initial phase, V sm 、V tm Sine wave amplitude and saw tooth wave amplitude of the previous period, respectively, +.>Initial phases of sine wave and saw tooth wave respectively, deltaV ism Sine wave amplitude error of imT to (i+1) mT period, deltaV imnt The sawtooth amplitude error is imnT to (i+1) mnT.
Further, when the current is measured, a first phase-locked loop is formed by a sine wave modulation signal with a period of T and a sine wave amplitude error signal with a period of mT, and the current to be measured is responded quickly;
a second phase-locked loop is formed by the sawtooth wave modulation signal with the period of mnT and the sawtooth wave amplitude error signal with the same period, so that the optical fiber current transformer works near the highest sensitivity.
Further, the digital-to-analog converter converts the modulation signal into an electric signal, and the electric signal converted by the digital-to-analog converter is applied to an optical phase modulator in the optical fiber current transformer after passing through the gain amplifying circuit to form a modulation phase in an interference light path.
The invention also comprises a phase-locked closed-loop control device for the optical fiber current transformer, which comprises the following steps:
the sampling unit is used for forming an interference light path signal after the modulation of the electric signal, converting the interference light path signal into a sensing electric signal and sending the sensing electric signal into the analog-to-digital converter for digital sampling;
the demodulation unit is used for processing the sensing electric signals of m modulation periods T and demodulating sampling values in mT time to obtain modulation depth errors and feedback phase errors;
a sine wave generation unit for generating a sine wave according to the modulation depth error;
a sawtooth wave generating unit, configured to process the feedback phase errors of N modulation periods T, and generate a sawtooth wave, where n=nm, and N is a positive integer;
the modulation unit is used for superposing the generated sine wave and saw-tooth wave and providing the sine wave and saw-tooth wave for the digital-to-analog converter to form a modulation signal;
and the conversion unit is used for converting the modulation signal into an electric signal through a digital-to-analog converter so as to realize the closed-loop control of the optical fiber current transformer.
The invention also includes a computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, which processor implements the method as described above when executing the computer program.
The invention also includes a storage medium having stored thereon a computer program which, when executed by a processor, implements a method as described above.
The beneficial effects of the invention are as follows: the invention adopts a high-frequency sine wave signal to modulate, modulates an interference light path signal carrying current information to be detected into a high-frequency carrier signal, calculates and obtains feedback phase errors by digital demodulation of harmonic components in the interference light path signal, and uses the feedback phase errors as measurement output of a mutual inductor to realize quick response of current to be detected, and calculates and obtains sine wave modulation depth errors and sine wave amplitude errors as sine wave amplitude feedback adjustment input to form a first phase-locked loop system; the low-frequency sawtooth wave signal is adopted for modulation, and feedback phases with the same magnitude and opposite directions as the Faraday phase shift caused by the current to be measured are generated, so that the mutual inductor works near the highest sensitivity, and the feedback phase error and the sawtooth amplitude value error obtained through demodulation are combined to serve as sawtooth amplitude value feedback adjustment input, so that a second phase-locked closed loop system is formed. The invention realizes the low bandwidth adaptability requirement of the optical fiber current transformer on the modulation and demodulation circuit, improves the measurement precision and the dynamic range of the transformer, and effectively reduces the design and manufacturing difficulty and the product cost of the transformer.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings may be obtained according to the drawings without inventive effort to those skilled in the art.
FIG. 1 is a flow chart of the method in this embodiment;
FIG. 2 is a schematic view of the structure of the device in the present embodiment;
FIG. 3 is a flow chart of the digital phase-locked closed-loop control of the optical fiber current transformer in the present embodiment;
FIG. 4 is a waveform diagram of a sine wave modulated signal and an interference optical path signal in the present embodiment;
FIG. 5 is a graph showing the first, second and fourth Bessel functions in the present embodiment;
FIG. 6 is a waveform diagram of a sawtooth modulation signal and an interference optical path signal in the present embodiment;
fig. 7 is a schematic diagram of superposition of sine wave and saw tooth wave modulated signals in this embodiment.
Fig. 8 is a schematic diagram of the structure of the computer device in this embodiment.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments.
As shown in fig. 1: a phase-locked closed-loop control method for an optical fiber current transformer comprises the following steps:
an input optical signal entering a modulator in the optical fiber current sensor forms an interference optical path signal after the modulation effect of an electric signal, and the interference optical path signal is converted into a sensing electric signal which is sent to an analog-to-digital converter for digital sampling;
digital sampling is carried out on the sensing electric signals of m modulation periods T, and sampling values in mT time are demodulated to obtain modulation depth errors and feedback phase errors;
generating a sine wave according to the modulation depth error;
generating a sawtooth wave by processing feedback phase errors of N modulation periods T, wherein N=nm and N is a positive integer;
superposing the generated sine wave and sawtooth wave, and providing the superposed sine wave and sawtooth wave for a digital-to-analog converter to form a modulation signal;
the modulating signal is converted into an electric signal through a digital-to-analog converter, and the closed-loop control of the optical fiber current transformer is realized by utilizing the electric signal.
In this embodiment, converting the interference optical path signal into the sensing electric signal and sending the sensing electric signal to the analog-to-digital converter for digital sampling includes:
converting the interference light path signal into a sensing electric signal through a photoelectric detector;
the sensing electric signal enters an analog-to-digital converter through a pre-amplifying circuit.
Demodulating the sampling value in mT time, comprising the following steps:
based on a digital phase-sensitive detection method, digital demodulation processing is carried out on interference light path signal sampling values of m modulation periods T, and amplitudes H of first harmonic, second harmonic and fourth harmonic are respectively taken 1i 、H 2i And H 4i ；
Based on the ratio of the Bessel function of two and four ordersAnd modulation depth->Correspondence, combining two-four harmonic ratio +.> Calculate modulation depth +.>
Calculating a feedback phase error according to a formulaThe calculation formula is as follows:
generating a sine wave according to the modulation depth error, comprising the steps of:
setting a sine wave period which is a modulation period T, and setting sine wave amplitude values to adjust every interval mT;
according to modulation depthCalculating to obtain modulation depth error->Wherein->Modulating depth for a target;
according to modulation depth errorCalculating sine wave amplitude error +.>Where k is the sine wave amplitude gain factor.
The feedback phase error of N modulation periods T is processed to generate a sawtooth wave, and the method comprises the following steps:
setting the sawtooth wave period as N modulation periods T, and setting the sawtooth wave amplitude value to be adjusted at intervals NT;
according to feedback phase errorCalculating feedback phase offset +.>
Based on feedback phase offsetCalculating saw-tooth amplitude error +.>Where h is the saw tooth amplitude gain factor.
Calculating feedback phase offsetThe method comprises the following steps:
feedback of phase error with demodulation values in m modulation periods TAs basic unit, analyzing the sampled values of N modulation periods T, and calculating to obtain N feedback phase errors +.>
Because of sawtooth voltage jump during sawtooth wave switching, j feedback phase errors are generated within the transition time tau after the jumpWherein j= [ τ/mT ]]，[]Representing the upward rounding from n feedback phase errors +.>J pieces of saw-tooth wave voltage jump post transition time tau are removed;
again for the remaining (n-j) feedback phase errorsFiltering to remove maximum value +.>And minimum->The feedback phase offset is:
the modulated signal obtained by superposing the sine wave and the sawtooth wave comprises:
where sawroot () represents a magnitude of 1, with mnT as the period,for the sawtooth voltage signal of initial phase, V sm 、V tm Sine wave amplitude and saw tooth wave amplitude of the previous period, respectively, +.>Initial phases of sine wave and saw tooth wave respectively, deltaV ism Sine wave amplitude error of imT to (i+1) mT period, deltaV imnt The sawtooth amplitude error is imnT to (i+1) mnT.
When the current is measured, a first phase-locked closed loop is formed by a sine wave modulation signal with a period of T and a sine wave amplitude value adjustment signal with a period of mT, and the current to be measured is responded quickly;
a second phase-locked loop is formed by the sawtooth wave modulation signal with the period of mnT and the sawtooth wave amplitude adjustment signal with the same period, so that the optical fiber current transformer works near the highest sensitivity.
The digital-to-analog converter converts the modulation signal into an electric signal, and the electric signal converted by the digital-to-analog converter is applied to an optical phase modulator in the optical fiber current transformer after passing through the gain amplifying circuit to form a modulation phase in an interference light path.
In the embodiment, a high-frequency sine wave signal is adopted for modulation, an interference light path signal carrying current information to be detected is modulated into a high-frequency carrier signal, and each harmonic component in the interference light path signal is digitally demodulated, so that on one hand, a feedback phase error is calculated and used as a measurement output of a mutual inductor, quick response of current to be detected is realized, on the other hand, a sine wave modulation depth error is calculated and obtained and is used as a sine wave amplitude feedback adjustment input, and a first phase-locked closed loop system is formed; the low-frequency sawtooth wave signal is adopted for modulation, and feedback phases with the same magnitude and opposite directions as the Faraday phase shift caused by the current to be detected are generated, so that the mutual inductor works near the highest sensitivity, and the feedback phase error obtained by demodulation is combined as sawtooth amplitude value feedback adjustment input, so that a second phase-locked closed loop system is formed. The invention realizes the low bandwidth adaptability requirement of the optical fiber current transformer on the modulation and demodulation circuit, improves the measurement precision and the dynamic range of the transformer, and effectively reduces the design and manufacturing difficulty and the product cost of the transformer.
As shown in fig. 2, the embodiment further includes a phase-locked closed-loop control device for an optical fiber current transformer, where the method includes:
the sampling unit is used for forming an interference light path signal after the modulation of the electric signal, converting the interference light path signal into a sensing electric signal and sending the sensing electric signal into the analog-to-digital converter for digital sampling;
the demodulation unit is used for processing the sensing electric signals of m modulation periods T and demodulating sampling values in mT time to obtain modulation depth errors and feedback phase errors;
a sine wave generation unit for generating a sine wave according to the modulation depth error;
the sawtooth wave generation unit is used for processing the feedback phase errors of N modulation periods T to generate sawtooth waves, wherein N=nm, and N is a positive integer;
the modulation unit is used for superposing the generated sine wave and the sawtooth wave and providing the sine wave and the sawtooth wave for the digital-to-analog converter to form a modulation signal;
the conversion unit is used for converting the modulation signal into an electric signal through the digital-to-analog converter, so that closed-loop control of the optical fiber current transformer is realized.
As shown in fig. 3, the sine wave modulation signal generation/adjustment method proposed in the present embodiment is as follows:
the generated sine wave period is a modulation period T;
based on the ratio of the Bessel function of two and four ordersAnd modulation depth->Correspondence, combining two-four harmonic ratio +.> Calculate modulation depth +.>
According to modulation depthCalculating to obtain modulation depth error-> For the target modulation depth, further calculate sine wave amplitude error +.>k is the gain coefficient, assuming that the sine wave amplitude of the previous period is V sm The generated sine wave has a magnitude of (V sm +ΔV ism ) The sine wave amplitude is adjusted once every interval mT time, and the generated sine wave modulation signal is that
The modulation phase generated by the sine wave modulation signal is proportional to the sine wave modulation voltage, and has
The sawtooth wave modulation signal generation/adjustment method provided by the invention comprises the following steps:
based on first and second order Bessel functionsAnd the amplitude H of the first and second harmonics 1i 、H 2i Calculating feedback phase error->The calculation formula is as follows:
analyzing the sampled values of the N modulation periods T (or mnT), and calculating to obtain N feedback phase errors
Because of sawtooth voltage jump during sawtooth wave switching, j feedback phase errors are generated within the transition time tau after the jumpWherein j= [ τ/mT ]]，[]Representing the upward rounding from n feedback phase errors +.>J saw-tooth voltage jumps are removed from the voltage sequence;
again for the remaining (n-j) feedback phase errorsFiltering to remove maximum value +.>And minimum->Feedback phase offset
Saw tooth amplitude errorh is the gain coefficient, assuming that the saw-tooth amplitude of the previous period is V tm The generated sawtooth wave has a magnitude of (V tm +ΔV imnt ) The amplitude of the sawtooth wave is adjusted once at intervals NT (or mnT), the period of the sawtooth wave is NT (or mnT), and the generated sawtooth wave modulation signal is
The modulation phase generated by the sawtooth modulation signal is proportional to the sawtooth modulation voltage, and has
The modulated signals after the sine wave and saw-tooth wave signals are overlapped are as follows:
where sawroot () represents a magnitude of 1, with mnT as the period,for the sawtooth voltage signal of initial phase, V sm 、V tm Sine wave and saw tooth wave amplitudes of previous period, respectively, +.>Initial phases of sine wave and saw tooth wave respectively, deltaV ism Sine wave amplitude error of imT to (i+1) mT period, deltaV imnt The sawtooth amplitude error is imnT to (i+1) mnT.
Based on the digital phase-locked closed-loop control method, when the optical fiber current transformer adopts sine wave and sawtooth wave modulation signals, the interference light path signals output by the photoelectric detector are
In (8)For the Faraday phase shift of the current to be measured, the feedback phase is generated by the sine wave and sawtooth wave modulation signals>Wherein->The modulation phases generated by the sine wave and saw tooth wave modulation signals are respectively, and tau is the transit time of the transmission optical signal in the mutual inductor.
For the first digital phase-locked closed-loop control, when the sine wave signal modulation is adopted, the modulation phase difference formed in the interference light path signal is
In (9)For modulating depth of sine wave, V sm Is the amplitude of sine wave, K sm The sine wave modulation period is T, which is the modulation factor of the phase modulator.
By substituting formula (9) into formula (8), the interference optical path signal can be rewritten as
In the aboveRepresenting the feedback phase error between the faraday phase shift and the sawtooth modulated signal phase.
Applied to the first class of Bessel function expansion (10), the interference optical path signal can be further expressed as
J in the above x Representing a first class of x-order Bessel functions. From equation (11), the feedback phase errorZero, inputThe output signal only contains even harmonic wave of modulation frequency; feedback phase error->When not zero, odd harmonics of the modulation frequency will appear in the output optical signal, as shown in fig. 4.
Based on digital phase-sensitive detection method, the amplitude of the first harmonic component, the second harmonic component and the fourth harmonic component of the demodulation interference light path signal is provided with
In the above, K a Representing the gain coefficient of the interference light path signal through the photoelectric detector, the pre-amplifying circuit and the analog-to-digital converter.
The first, second and fourth order Bessel function curves and the second, fourth order values are shown in figure 5. Based on the ratio of the Bessel function of two and four ordersAnd modulation depth->Correspondence, combining two-four harmonic amplitude ratioModulation depth->Is that
Assuming a target modulation depth ofCalculating to obtain modulation depth error->Modulation depth according to formula (9)>Amplitude V of sine wave sm Linear correlation, and thus sine wave amplitude error +.>k is the gain factor. Let the sine wave amplitude of the previous period be V sm The amplitude of the sine wave after feedback is (V sm +ΔV sm ) The sine wave amplitude is adjusted once every interval mT time, so that the generated sine wave modulation signal is
The modulation phase generated by the sine wave signal is proportional to the sine wave modulation voltage, and has
For the second digital phase-locked closed loop control, sawtooth signal modulation is used, as shown in fig. 6. Let the amplitude of the sawtooth wave be V tm The modulation period is mnT, and the modulation phase difference generated in the (mnT-tau) time period is equal to V in one modulation period tm T/mnT linear correlation, modulation phase difference of T time period and-V tm (mnT- τ)/mnT, there is
As can be seen from (12), the sampling value in the ith mT period is demodulated based on the first and second harmonic amplitude H 1i 、H 2i And first and second order Bessel functionsDemodulation feedback phase error->Is that
By analyzing the sampling value of the sawtooth wave in one modulation period mnT time, n feedback phase errors can be obtained by calculationBecause of sawtooth voltage jump when the sawtooth signal is switched, j feedback phase errors are generated within the transition time tau after the jump>Wherein j= [ τ/mT ]]，[]Representing the upward rounding from n feedback phase errors +.>J saw-tooth voltage jumps are removed from the voltage sequence; then for the remaining (n-j) feedback phase errors +.>Filtering to remove maximum value +.>And minimum->Feedback phase offset
Modulating phase according to sawtooth wave (16)And saw-tooth wave amplitude V tm Linear correlation, calculating the saw-tooth amplitude error +.>h is the gain factor. Let the saw-tooth wave amplitude of the previous period be V tm The period of the sawtooth wave is mnT, and the amplitude of the sawtooth wave after feedback adjustment is (V tm +ΔV mnt ) The amplitude of the sawtooth wave is adjusted once every mnT time, and the initial phase is +.>The generated sawtooth wave modulation signal is
The modulation phase generated by the sawtooth modulation signal is proportional to the sawtooth modulation voltage, and has
As shown in fig. 7, the modulated signals formed by superimposing the sine wave and saw-tooth wave signals are:
to sum up, on the one hand, feedback phase error is adoptedAnd sawtooth modulation phase->As the demodulation output of the current to be measured, the rapid response of the current to be measured can be realized. On the other hand, feedback phase error +.>Used as a feedback input for sawtooth modulated signals such that the Faraday phase shift is +.>Modulation phase with sawtooth wave>Difference betweenThe first harmonic component in the formula (12) shows that the transformer always works at the highest sensitivity point, so that the measurement accuracy and the dynamic range of the transformer are improved. In addition, the bandwidth requirement of a system modulation and demodulation circuit and the design and manufacturing cost of a transformer product are effectively reduced by adopting a high-frequency sine wave modulation signal and a low-frequency sawtooth wave modulation signal.
Please refer to fig. 8, which illustrates a schematic structural diagram of a computer device provided in an embodiment of the present application. The embodiment of the present application provides a computer device 400, including: a processor 410 and a memory 420, the memory 420 storing a computer program executable by the processor 410, which when executed by the processor 410 performs the method as described above.
The present embodiment also provides a storage medium 430, on which storage medium 430 a computer program is stored which, when executed by the processor 410, performs a method as above.
The storage medium 430 may be implemented by any type or combination of volatile or nonvolatile Memory devices, such as a static random access Memory (Static Random Access Memory, SRAM), an electrically erasable Programmable Read-Only Memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), an erasable Programmable Read-Only Memory (Erasable Programmable Read Only Memory, EPROM), a Programmable Read-Only Memory (PROM), a Read-Only Memory (ROM), a magnetic Memory, a flash Memory, a magnetic disk, or an optical disk.
In the description of the present invention, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. The meaning of "a plurality of" is two or more, unless specifically defined otherwise.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily for the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and further implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
Logic and/or steps represented in the flowcharts or otherwise described herein, e.g., a ordered listing of executable instructions for implementing logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program is printed, as the program may be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.
It is to be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.
Those of ordinary skill in the art will appreciate that all or a portion of the steps carried out in the method of the above-described embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a computer readable storage medium, and where the program, when executed, includes one or a combination of the steps of the method embodiments.
The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, or the like. While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (11)
1. A phase-locked closed-loop control method for an optical fiber current transformer is characterized by comprising the following steps:
an input optical signal entering a modulator in the optical fiber current transformer forms an interference optical path signal after the modulation action of an electric signal, and the interference optical path signal is converted into a sensing electric signal and is digitally sampled;
digital sampling is carried out on the sensing electric signals of m modulation periods T, and sampling values in mT time are demodulated to obtain modulation depth errors and feedback phase errors;
generating a sine wave according to the modulation depth error;
generating a sawtooth wave for the feedback phase error processing of N modulation periods T, wherein N=nm, and N is a positive integer;
superposing the generated sine wave and saw tooth wave under a set period to form a modulation signal;
and converting the modulation signal into an electric signal, and realizing closed-loop control of the optical fiber current transformer by utilizing the electric signal.
2. The phase-locked closed loop control method for a fiber current transformer according to claim 1, wherein demodulating the sampling value in mT time comprises the steps of:
based on a digital phase-sensitive detection method, carrying out digital processing on the interference light path signals of m modulation periods T, and respectively taking the amplitudes H of first harmonic, second harmonic and fourth harmonic 1i 、H 2i And H 4i ；
Based on the ratio of the Bessel function of two and four ordersAnd modulation depth->The corresponding relation satisfies +.>Calculate modulation depth +.>
Calculating a feedback phase error according to a formulaThe calculation formula is as follows:
3. the phase-locked closed-loop control method for an optical fiber current transformer according to claim 2, wherein the generating a sine wave according to the modulation depth error comprises the steps of:
setting a sine wave period as a modulation period T, and setting sine wave amplitude values to be adjusted at intervals mT;
according to modulation depthCalculating the modulation depth error->Wherein->Modulating depth for a target;
according to the modulation depth errorCalculating sine wave amplitude error +.>Where k is the sine wave amplitude gain factor.
4. A phase-locked closed-loop control method for an optical fiber current transformer according to claim 3, wherein said feedback phase error processing for N modulation periods T generates a sawtooth wave, comprising the steps of:
setting the sawtooth wave period as N modulation periods T, and setting the sawtooth wave amplitude value to be adjusted at intervals NT;
according to the feedback phase errorCalculating feedback phase offset +.>
Based on the feedback phase offsetCalculating saw-tooth amplitude error +.>Where h is the saw tooth amplitude gain factor.
5. The phase-locked loop control method for an optical fiber current transformer according to claim 4, wherein said calculating a feedback phase offsetThe method comprises the following steps:
feedback of phase error with demodulation values in m modulation periods TAs basic unit, analyzing the sampled values of N modulation periods T, and calculating to obtain N feedback phase errors +.>
Because of saw-tooth voltage jump exists during saw-tooth wave switching, j feedback phase errors are generated within the transition time tau after the jumpWherein j= [ τ/mT ]]，[]Representing the upward rounding from n feedback phase errors +.>J pieces of saw-tooth wave voltage jump post transition time tau are removed;
again for the remaining (n-j) feedback phase errorsFiltering to remove maximum value +.>And minimum valueThe feedback phase offset is:
6. the phase-locked closed-loop control method for an optical fiber current transformer according to claim 4, wherein the modulating signal obtained by superimposing the sine wave and the sawtooth wave comprises:
where sawroot () represents a magnitude of 1, with mnT as the period,for the sawtooth voltage signal of initial phase, V sm 、V tm Sine wave amplitude and saw tooth wave amplitude of the previous period, respectively, +.>Initial phases of sine wave and saw tooth wave respectively, deltaV ism Sine wave amplitude error of imT to (i+1) mT period, deltaV imnt The sawtooth amplitude error is imnT to (i+1) mnT.
7. The phase-locked loop control method for an optical fiber current transformer according to claim 4, wherein a first phase-locked loop is formed by a sine wave modulation signal with a period of T and a sine wave amplitude error signal with a period of mT when measuring a current;
a second phase-locked loop is formed from a sawtooth modulated signal of period mnT and a sawtooth amplitude error signal of the same period.
8. The phase-locked loop control method for an optical fiber current transformer according to claim 1, wherein the digital-to-analog converter converts the modulated signal into an electrical signal, and the electrical signal converted by the digital-to-analog converter is applied to an optical phase modulator in the optical fiber current transformer after passing through a gain amplifying circuit to form a modulation phase in an interference optical path.
9. A phase-locked closed loop control device for an optical fiber current transformer, characterized by using the method as claimed in any one of claims 1 to 8, comprising:
the sampling unit is used for forming an interference light path signal after the modulation of the electric signal, converting the interference light path signal into a sensing electric signal and sending the sensing electric signal into the analog-to-digital converter for digital sampling;
the demodulation unit is used for processing the sensing electric signals of m modulation periods T and demodulating sampling values in mT time to obtain modulation depth errors and feedback phase errors;
a sine wave generation unit for generating a sine wave according to the modulation depth error;
a sawtooth wave generating unit, configured to process the feedback phase errors of N modulation periods T, and generate a sawtooth wave, where n=nm, and N is a positive integer;
the modulation unit is used for superposing the generated sine wave and saw-tooth wave and providing the sine wave and saw-tooth wave for the digital-to-analog converter to form a modulation signal;
and the conversion unit is used for converting the modulation signal into an electric signal through a digital-to-analog converter so as to realize the closed-loop control of the optical fiber current transformer.
10. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the method of any of claims 1-8 when executing the computer program.
11. A storage medium having stored thereon a computer program which, when executed by a processor, implements the method of any of claims 1-8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311415719.7A CN117471146A (en) | 2023-10-27 | 2023-10-27 | Phase-locked closed-loop control method, device, equipment and medium for optical fiber current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311415719.7A CN117471146A (en) | 2023-10-27 | 2023-10-27 | Phase-locked closed-loop control method, device, equipment and medium for optical fiber current transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117471146A true CN117471146A (en) | 2024-01-30 |
Family
ID=89623169
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311415719.7A Pending CN117471146A (en) | 2023-10-27 | 2023-10-27 | Phase-locked closed-loop control method, device, equipment and medium for optical fiber current transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117471146A (en) |
-
2023
- 2023-10-27 CN CN202311415719.7A patent/CN117471146A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8175465B2 (en) | Bias control apparatus and method for optical modulator | |
| US10209321B2 (en) | External magnetic field angle determination | |
| US9124206B2 (en) | Method and arrangement for determining the position of a rotor in a brushless motor or in stepper motor | |
| US8004274B2 (en) | Inductive position sensor | |
| US8823362B2 (en) | Current sensor arrangement for measuring currents in a primary conductor | |
| JPS63284480A (en) | Digitizing and linearizing system of transducer having quasi-sinusoid period characteristic | |
| JP4937803B2 (en) | Optical gyroscope digital feedback system and method | |
| Magnani et al. | Self-mixing digital closed-loop vibrometer for high accuracy vibration measurements | |
| CN108414951B (en) | Method and device for periodically modulating sensitivity of magnetic sensor to reduce noise of device | |
| JP2007132941A (en) | Asynchronous demodulation in optical fiber gyroscope | |
| EP2593799A1 (en) | Current measurement apparatus and current measurement method thereof | |
| US10491236B2 (en) | Offset compensation circuit for a tracking loop | |
| US4039946A (en) | Tachometer | |
| KR20220025699A (en) | An electronic circuit that measures the angle and strength of an external magnetic field. | |
| CN117471146A (en) | Phase-locked closed-loop control method, device, equipment and medium for optical fiber current transformer | |
| US8278915B2 (en) | Minimizing magnetic interference in a variable reluctance resolver | |
| CN108132062B (en) | Optical fiber gyroscope optical path power detection method and device based on four-frequency-division four-state modulation | |
| US3983475A (en) | Frequency selective detecting system for detecting alternating magnetic fields | |
| CN1347554A (en) | Device for scanning rotating information carrier | |
| US5555235A (en) | Optical fiber gyro with memory storing data measured under application of angular velocity | |
| US20210165013A1 (en) | Adaptive filter for motor speed measurement system | |
| JPH0743404A (en) | Phase difference detecting method, circuit and apparatus | |
| JPS6047782B2 (en) | Light emitting element output stabilization circuit | |
| JPH05508222A (en) | Single-stage demodulator using reference signal phase fluctuation method | |
| CN109814047B (en) | TMR sensor with low 1/f noise |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |