CN102981136A - Method for calibrating dynamic performances of fiber optical current transducer (FOCT) based on voltage modulation - Google Patents

Abstract

The invention discloses a method for calibrating dynamic performances of an FOCT based on voltage modulation. Additional voltage modulation phases are introduced in a digital closed-loop signal processing process of the FOCT to simulate optical nonreciprocity Farady phases caused by power line currents, segment treatment is performed to output data of the FOCT by using a segment modulation phase method to calibrate scale factors of the FOCT, and the linearity, the symmetry and the repeatability of the scale factors of the FOCT are analyzed. According to the method, the method starts from a digital closed-loop signal processing process of the FOCT, dynamic performances of the FOCT are estimated overall, the method has the advantages of being simple and direct in testing process and high in calibration accuracy, and test calibration of a plurality of sets of FOCTs can be completed for one time.

Description

Optical fiber current mutual inductor dynamic property scaling method based on voltage modulated

Technical field

The invention belongs to the Electrical Measurement Technology field, relate to a kind of optical fiber current mutual inductor dynamic property quick calibrating method based on voltage modulated.

Background technology

Optical fiber current mutual inductor has overcome the limitation of electromagnetic current transducer at aspects such as accuracy, dynamic range and direct current measurements; not only first-harmonic is measured accurate; and direct current and each harmonic can both Measurement accuracies; have wide dynamic range, good insulation preformance, measuring accuracy advantages of higher; can satisfy the demand of the field developments such as the dynamic observation of electric energy metrical, electric energy quality monitoring, protection control, failure wave-recording and electrical network; represent the developing direction of current transformer, adapted to the growth requirement of intelligent grid.Optical fiber current mutual inductor is a member important in the sensory field of optic fibre, it is the optical interdferometer that is based upon on the Farady magneto-optic effect basis, the light wave that namely in closed light path, sends from same light source, process through polarization characteristic, form two bundle polarized lights of left and right sides circular polarization characteristic, propagate along identical direction, and converge to same sensing point and produce interference; If closed light path is subjected to the impact of current field, then two of left and right sides circular polarization characteristic bundle polarized lightwaves produce optical path difference, Farady phase differential corresponding to this optical path difference is directly proportional with the carrier magnitude of current, the signal processing system of optical fiber current mutual inductor obtains the carrier magnitude of current by carrying out modulation /demodulation to phase of light wave is poor.Optical fiber current mutual inductor is measured in real time the nonreciprocity phasing degree that is caused by magnetic field Farady effect in the light wave loop, and then is obtained foreign current information by using for reference optical fibre gyro photosignal digital closed loop feedback technique.Electromagnetic field-light wave inductive coupling technology and digital closed loop feedback signal treatment technology make optical fiber current mutual inductor have the advantages such as wide dynamic range, measuring accuracy height, good insulation preformance.Optical fiber current mutual inductor has overcome the weakness such as the existing hysteresis ﹠ saturation of electromagnetic current transducer, wave form distortion, satisfies modern power systems to the demand of current measurement value reliability.

At present, the static characteristics test of optical fiber current mutual inductor formed more unified method both at home and abroad, and be not a lot of to the research of the dynamic perfromance of optical fiber current mutual inductor, yet, the dynamic perfromance of optical fiber current mutual inductor is the important performance indexes that characterizes its reliability and environmental suitability, its quality has directly determined the range of application of optical fiber current mutual inductor, and the method for testing of optical fiber current mutual inductor is restricting the raising of optical fiber current mutual inductor precision to a certain extent.High-precision optical fiber current mutual inductor must possess good dynamic perfromance.When optical fiber current mutual inductor is applied to transmission of electricity, transformer substation system, there is very high requirement in system to the dynamic perfromance index of optical fiber current mutual inductor, therefore, the dynamic perfromance of test analysis optical fiber current mutual inductor is to determine the important evidence of optical fiber current mutual inductor reliability.

At present, the dynamic characteristic test calibration process of optical fiber current mutual inductor is to finish on the high-current test platform, in the test calibration process, need heavy current breaker, distinctive signal generator, caliberating device etc., owing to there are the problems such as energy resource consumption is large, equipment amortization in the test process, there is the limited technical indicators such as calibration with current signal scope restriction in the calibration with current signal device in addition, causes the optical fiber current mutual inductor dynamic characteristic test to have the problem of the aspects such as somewhat expensive, test process is loaded down with trivial details, efficient is low.

Summary of the invention

Technical matters: the objective of the invention is to overcome a prior art difficult problem, in conjunction with the optical fiber current mutual inductor signal processing technology, provide a kind of need not to demarcate on-the-spot test at current transformer, simple in structure, reduced the requirement to test environment, and can single batch finish many optical fiber current mutual inductor dynamic characteristic tests and demarcate, workable, the optical fiber current mutual inductor dynamic property scaling method based on voltage modulated that efficient is high.

Technical scheme: the optical fiber current mutual inductor dynamic property scaling method based on voltage modulated of the present invention may further comprise the steps:

1) the electrooptical modulation signal input part with three optical fiber current mutual inductors links to each other with the voltage signal output end of a phase modulation voltage controller, and the signal output part of optical fiber current mutual inductor links to each other with the data recording device;

2) voltage of control phase modulation voltage controller output null value, the output sequence of values of record three optical fiber current mutual inductors this moment respectively, and the average that seeks out sequence of values is respectively F10, F20, F30;

3) according to the half-wave voltage parameter of integrated optics chip in the optical fiber current mutual inductor, get Δ U=(U _n)/n, Un is the half-wave voltage value of integrated optics chip, n is the integer greater than 5, regulate the phase modulation voltage controller and export successively, Δ U initial take 0.0V and be incremental change, until be incremented to the half-wave voltage parameter of integrated optics chip, forms the contact potential series of n magnitude of voltage composition, be 0.0V, Δ U, 2 Δ U ... U _nCorresponding different modulating voltage value, record respectively three optical fiber current mutual inductors output numerical value equal value sequence for F110, F120 ... F1n0 }, and F210, F220 ... F2n0 } and F310, F320 ... F3n0 }; Then, the equal value sequence of three optical fiber current mutual inductors output numerical value is deducted respectively step 2) in the average F10 of optical fiber current mutual inductor output numerical value of record, F20, F30, namely obtain the nothing zero inclined to one side average sequence { F11 of the output data of three optical fiber current mutual inductors under difference control magnitude of voltage, F12 ... F1n }, { F21, F22, F2n } and F31, F32 ... F3n };

4) after being closed, optical fiber current mutual inductor restarts again, with the positive and negative switching of the output voltage of phase modulation voltage controller, then controlling output voltage is null value, record respectively the output sequence of values of three optical fiber current mutual inductors this moment, and the average that seeks out sequence of values is respectively NF10, NF20, NF30;

5) the reverse voltage sequence that the output of control phase modulation voltage controller is opposite with contact potential series polarity in the step 3), amplitude equates, the average of the output numerical value when recording respectively the corresponding different voltage value of three unjacketed optical fiber current transformers is { NF110, NF120, NF1n0 }, { NF210, NF220, NF2n0 }, NF310, NF320 ... NF3n0 }; Then, the equal value sequence with three optical fiber current mutual inductor output numerical value deducts respectively the average NF10 that the optical fiber current mutual inductor that records in the step 4) is exported numerical value, NF20, NF30, namely obtain partially average sequence { NF11 of nothing zero that three optical fiber current mutual inductors oppositely control the output data under the magnitude of voltage in difference, NF12 ... NF1n }, { NF21, NF22 ... NF2n }, { NF31, NF32 ... NF3n };

The nothing zero of the output numerical value during the corresponding different voltage value of three optical fiber current mutual inductors that 6) obtains according to step 3) is average sequence { F11 partially, F12, ... F1n }, { F21, F22, ... F2n }, { F31, F32, ... F3n }, the nothing zero of the output numerical value during with the corresponding different voltage value of three optical fiber current mutual inductors of step 5) record is average sequence { NF11 partially, NF12 ... NF1n }, { NF21, NF22 ... NF2n }, { NF31, NF32, ... NF3n }, go out the range of optical fiber current mutual inductor by the half-wave voltage parameter value calculation of integrated optics chip, calculate the constant multiplier of optical fiber current mutual inductor according to the constant multiplier computing formula, the scale factory non-linearity degree, constant multiplier asymmetry and constant multiplier repeatability.

Principle of the present invention is:

The ultimate principle of optical fiber current mutual inductor is based upon on the magneto-optic Farady effect basis exactly, and current field causes the two-beam ripple in the optical fiber to produce optical path difference, and then draws magneto-optic Farady phase place Φ correspondingly _S:

Φ _S=(4NV)*I _out （1）

Wherein, Φ _SBe the Farady effect phase differential that current field causes, N is the optical fiber number of turn, and V is the German number of Wei Er, I _OutBe the power line current amount, the parameters such as optical fiber number of turn N, the German number of Wei Er are definite value, therefore, and the output phase shift Φ of current transformer _SWith input current amount I _OutBe directly proportional; Optical fiber current mutual inductor utilizes magneto-optic Farady effect exactly, and by light beam in the fiber optic loop is carried out phase demodulating, and then the variation of responsive phase place comes the current information of perception outer carrier.

At present, aspect the processing of optical fiber current mutual inductor signal, all adopt the digital closed loop signal processing technology both at home and abroad.The digital closed loop optical fiber current mutual inductor is by add nonreciprocal compensating phase shift in fiber optic loop, offset by fiber optic loop and rotate the magneto-optic Farady phase shift that produces, this compensating phase shift and magneto-optic Farady phase shift equal and opposite in direction, opposite direction, make optical fiber current mutual inductor always work in phase place near zero point, draw the tach signal of optical fiber current mutual inductor by the size of obtaining this compensating phase shift.

Optical fiber current mutual inductor digital closed loop signal processing system mainly is comprised of light source, coupling mechanism, integrated optics modulation chip (IOC), wave plate, photodetector, fiber optic loop and catoptron.The light that light source sends is risen partially by polarizer through behind the coupling mechanism, forms linearly polarized light; Linearly polarized light injects polarization maintaining optical fibre with 45° angle, is on average injected X-axis and the Y-axis transmission of polarization maintaining optical fibre; Behind light process λ/4 wave plates of this two bundles orthogonal modes, change into respectively left-handed and circularly polarized light dextrorotation, enter sensor fibre; Because transmission current produces magnetic field Farady effect, two bundle circularly polarized lights are with different speed transmission in sensor fibre; Behind the mirror-reflection by the sensor fibre end face, the polarization modes of two bundle circularly polarized lights exchange, and again pass conduction optical fiber, and the magnetic field interaction that again produces with electric current, and the phase place of generation is doubled; Comprise the two-beam of Farady phase differential again by behind λ/4 wave plates, revert to linearly polarized light, and interfere at the polarizer place, interfere light wave to enter the PIN photoelectric detector through coupling mechanism.

The PIN detector detects the interference signal light intensity to be changed, amplify through photosignal, filtering, after the A/D conversion process, send into the FPGA/DSP signal processing system, form the close-loop feedback voltage signal and come the modulation electric optical phase modulator, make phase-modulator in fiber optic loop, add nonreciprocal feedback compensation phase shift, the Farady phase shift equal and opposite in direction that this feedback phase shift and foreign current cause, opposite direction, make the optical fiber current mutual inductor closed-loop system always work in phase place near zero point, signal processing system is by obtaining the size of this compensating phase shift, and conversion draws the current information of line of electric force through scale factor.

The optical interference signal that PIN detects is:

I=I ₀[1+cos(Φ _S+Φ _f+Φ _J)] （2）

Through opto-electronic conversion, the voltage signal of output is V=KI ₀[1+cos (Φ _S+ Φ _f+ Φ _J)], wherein, K is photoelectric conversion factors, Φ _SFor current signal produces nonreciprocal phase shift, Φ _S=(4NV) I _Out, I _OutBe tested electric current, Φ _fFor square wave produces the biasing nonreciprocal phase shift, be used for improving the sensitivity of input and differentiate direction of current, Φ _JFor staircase waveform produces nonreciprocal phase shift, N is the optical fiber number of turn, and V is the German number of Wei Er.

Square-wave signal produces phase shift in positive-negative half-cycle, the staircase waveform increment is used for compensating outside magneto-optic Farady phase shift, square wave and staircase waveform modulation signal all add after the phase-modulator, and the nonreciprocal phase shift that produces in current transformer is ΔΦ=Φ _S+ Φ _f+ Φ _J, at the positive half cycle of square wave, Φ _f=pi/2, the output signal of interferometer is:

V ₁=KI ₀[1-sin(Φ _S+Φ _J)] （3）

At the negative half period of square wave, Φ _f=-pi/2, the output signal of interferometer is:

V ₂=KI ₀[1+sin(Φ _S+Φ _J)] （4）

The positive half cycle signal of square wave (3) and negative half-cycle signal (4) are subtracted each other and can get:

ΔV=-2KI ₀sin(Φ _S+Φ _J) （5）

Make Φ by close-loop feedback _S=-Φ _JGuarantee Δ V=0, and when Δ V ≠ 0, just remove Control loop feedback staircase generator with Δ V as controlled quentity controlled variable, the change staircase waveform is in voltage increment, this voltage increment and the light wave phase shift phi of incremental stages generation _JProportional, make all the time Φ by close-loop feedback control _S+ Φ _J=0, when digital closed loop reached balance, the ladder height increment of staircase waveform was directly proportional with measured electric current, and the staircase waveform height gain is with regard to the current signal of corresponding optical fiber current mutual inductor output.Ideally, by close-loop feedback control, the interference signal that photodetector PIN detects is zero level.

In the present invention, the phase modulation voltage controller applies control voltage to phase-modulator, is equivalent to introduce in optical loop nonreciprocal optical phase Φ _IOC, at phase-modulator controllable voltage scope (in the all-wave voltage range, magnitude of voltage generally is no more than 12V), Φ _IOCWith voltage V _IOCBetween linear:

Φ _IOC=K _IOC*V _IOC （6）

Wherein, K _IOCBe the fixed proportion constant.

In this invention, when the electric current of wire that optical fiber current mutual inductor is surveyed was zero, because factors such as external magnetic fields, it was Φ that the optical fiber current mutual inductor fiber optic loop is sensed initial Farady phase place ₀, corresponding initial current is I ₀, in IOC, apply voltage V by the phase modulation voltage controller _IOC, in optical loop, added additional phase modulation Φ _C, total non-reciprocal phase is in the fiber optic loop at this moment:

Φ _T=Φ ₀+Φ _C （7）

Because Φ ₀Be steady state value, by measuring Φ under the different voltage input conditions _T, in conjunction with the signal processing of optical fiber current mutual inductor closed loop feedback system, can draw Φ _J, Φ _T, Φ _C, I _Out, Φ _T, V _IOCSatisfy following relation:

Φ _J＝-Φ _T （8）

Φ _C=Φ _T-Φ ₀=K _IOC*V _IOC （9）

Φ _C=(4NV)*I _out=K _IOC*V _IOC （10）

V _IOC=-[(4NV)/K _IOC]*I _out （11）

By the derivation of formula (7) to formula (11), can find out that the phase modulation voltage controller applies voltage V in IOC _IOCLinear with the electric current that optical fiber current mutual inductor is measured, according to this principle, can measure optical fiber current mutual inductor output corresponding to half-wave voltage of phase modulator (this voltage is no more than 12V usually), and can apply different magnitudes of voltage, measure different angular speed output, avoided current transformer to demarcate the complicated procedures of testing on the test platform, overcome the restriction of demarcating the test platform current amplitude, realized adopting low voltage signal to finish the quick test calibration of optical fiber current mutual inductor dynamic perfromance very much.

Beneficial effect: the present invention compared with prior art has the following advantages:

In existing optical fiber current mutual inductor dynamic perfromance calibration process, need the special strong current generator that is equipped with, the devices such as Transient Analysis instrument, tester need special experimental situation, have the deficiencies such as testing expense height, efficient are low; The present invention starts with from optical fiber current mutual inductor digital closed loop signal processing method, by in optical fiber current mutual inductor digital closed loop signal processing, introducing the additional modulation phase place, simulate the optics nonreciprocity Farady phase place that the foreign current amount causes, introduce the half-wave voltage modulator approach and come the range of measuring fiber current transformer, and the dynamic range of nominal light fiber current mutual inductor, in addition, adopt the way of segmentation phase modulation, optical fiber current mutual inductor output data are carried out staging treating, calculate the constant multiplier of optical fiber current mutual inductor, and the linearity of nominal light fiber current mutual inductor constant multiplier, symmetry, repeatability.

The present invention is directed to optical fiber current mutual inductor digital closed loop signal treatment characteristic, assess on the whole the dynamic perfromance of optical fiber current mutual inductor with a kind of brand-new method, have the advantages that test process is simple and direct, measurement range is large, stated accuracy is high, and can single finish the test calibration of many unjacketed optical fibers current transformer, have the high characteristics of efficient.Solved in existing calibration process, because method of testing and the restriction of calibration facility technical indicator cause the accuracy of test result relatively poor, measuring accuracy is lower, testing expense is high, inefficient problem.

Description of drawings

Fig. 1 is the structural drawing of optical fiber current mutual inductor,

Fig. 2 is the system construction drawing of the inventive method,

Fig. 3 is the process flow diagram of the inventive method.

Embodiment

The invention will be further described below in conjunction with the drawings and specific embodiments.

As seen from Figure 1, the optical fiber current mutual inductor digital closed-loop system mainly (claims again integrated optics chip, IOC), wave plate, photodetector and fiber optic loop form by light source, coupling mechanism, polarizer, phase-modulator.

The light that light source sends is through coupling mechanism, polarizer, form the light wave of two kinds of circular polarization states behind the wave plate, enter the optical sensor ring, the light wave of these two kinds of circular polarization states is propagated in fiber optic loop, the electric current motion of the induced electricity line of force, detecting the interference signal light intensity at the detector place changes, amplify through photosignal, filtering, after the A/D conversion process, send into the FPGA/DSP signal processing system, form the close-loop feedback voltage signal and come the modulation electric optical phase modulator, make phase-modulator in fiber optic loop, add nonreciprocal feedback compensation phase shift, the Farady phase shift equal and opposite in direction that this feedback phase shift and foreign current cause, opposite direction, make the optical fiber current mutual inductor closed-loop system always work in phase place near zero point, signal processing system is by obtaining the size of this compensating phase shift, and conversion draws the current information of line of electric force through scale factor.

As seen from Figure 2, the system of the inventive method is comprised of phase modulation voltage controller, tested optical fiber current transformer, data record apparatus and data analysis system.Optical fiber current mutual inductor output data export the data recording unit to according to serial data format, then reach data analysis system by the data recording unit rotary speed data that different modulating voltage is corresponding.

Optical fiber current mutual inductor dynamic property scaling method based on voltage modulated of the present invention may further comprise the steps:

1) the electrooptical modulation signal input part with three optical fiber current mutual inductors links to each other with the voltage signal output end of a phase modulation voltage controller, and the signal output part of optical fiber current mutual inductor links to each other with the data recording device;

2) voltage of control phase modulation voltage controller output null value, the output sequence of values of record three optical fiber current mutual inductors this moment respectively, and the average that seeks out sequence of values is respectively F10, F20, F30;

3) according to the half-wave voltage parameter of integrated optics chip in the optical fiber current mutual inductor, get Δ U=(U _n)/n, Un is the half-wave voltage value of integrated optics chip, n is the integer greater than 5, regulate the phase modulation voltage controller and export successively, Δ U initial take 0.0V and be incremental change, until be incremented to the half-wave voltage parameter of integrated optics chip, forms the contact potential series of n magnitude of voltage composition, be 0.0V, Δ U, 2 Δ U ... U _nCorresponding different modulating voltage value, record respectively three optical fiber current mutual inductors output numerical value equal value sequence for F110, F120 ... F1n0 }, and F210, F220 ... F2n0 } and F310, F320 ... F3n0 }; Then, the equal value sequence of three optical fiber current mutual inductors output numerical value is deducted respectively step 2) in the average F10 of optical fiber current mutual inductor output numerical value of record, F20, F30, namely obtain the nothing zero inclined to one side average sequence { F11 of the output data of three optical fiber current mutual inductors under difference control magnitude of voltage, F12 ... F1n }, { F21, F22, F2n } and F31, F32 ... F3n };

4) after being closed, optical fiber current mutual inductor restarts again, with the positive and negative switching of the output voltage of phase modulation voltage controller, then controlling output voltage is null value, record respectively the output sequence of values of three optical fiber current mutual inductors this moment, and the average that seeks out sequence of values is respectively NF10, NF20, NF30;

5) the reverse voltage sequence that the output of control phase modulation voltage controller is opposite with contact potential series polarity in the step 3), amplitude equates, the average of the output numerical value when recording respectively the corresponding different voltage value of three unjacketed optical fiber current transformers is { NF110, NF120, NF1n0 }, { NF210, NF220, NF2n0 }, NF310, NF320 ... NF3n0 }; Then, the equal value sequence with three optical fiber current mutual inductor output numerical value deducts respectively the average NF10 that the optical fiber current mutual inductor that records in the step 4) is exported numerical value, NF20, NF30, namely obtain partially average sequence { NF11 of nothing zero that three optical fiber current mutual inductors oppositely control the output data under the magnitude of voltage in difference, NF12 ... NF1n }, { NF21, NF22 ... NF2n }, { NF31, NF32 ... NF3n };

The nothing zero of the output numerical value during the corresponding different voltage value of three optical fiber current mutual inductors that 6) obtains according to step 3) is average sequence { F11 partially, F12, ... F1n }, { F21, F22, ... F2n }, { F31, F32, ... F3n }, the nothing zero of the output numerical value during with the corresponding different voltage value of three optical fiber current mutual inductors of step 5) record is average sequence { NF11 partially, NF12 ... NF1n }, { NF21, NF22 ... NF2n }, { NF31, NF32, ... NF3n }, go out the range of optical fiber current mutual inductor by the half-wave voltage parameter value calculation of integrated optics chip, calculate the constant multiplier of optical fiber current mutual inductor according to the constant multiplier computing formula, the scale factory non-linearity degree, constant multiplier asymmetry and constant multiplier repeatability.

The constant multiplier K computing method of optical fiber current mutual inductor are as follows:

If

Be j modulation input voltage V _jThe time, the mean value of N data of optical fiber current mutual inductor output, F _JpBe p data in N the data,

During for the test beginning, during acyclic homologically trioial voltage input processed, the average of optical fiber current mutual inductor output data; The constant multiplier computing method are seen formula (12) ~ (16):

${\stackrel{\‾}{F}}_j=\frac{1}{N}\underset{p=1}{\overset{1}{\mathrm{\Σ}}}{F}_{\mathrm{jp}}---\left(12\right)$

$F_j={\stackrel{\‾}{F}}_j-{\stackrel{\‾}{F}}_r---\left(13\right)$

Set up the linear model of optical fiber current mutual inductor input/output relation:

F _j＝K·V _j+F ₀+Δ _j （14）

Wherein, j modulation input voltage V _j, K is constant multiplier, F ₀Be match zero-bit, Δ _jBe error of fitting.

Ask K, F with least square method ₀:

$K=\frac{\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{V}_j\·F_j-\frac{1}{M}\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{V}_j\·\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{F}_j}{\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{V}_j^2-\frac{1}{M}{\left(\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{V}_j\right)}^2}---\left(15\right)$

$F_0=\frac{1}{M}\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{F}_j-\frac{K}{M}\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{V}_j---\left(16\right)$

Range (the I of optical fiber current mutual inductor _Max-I _Max+) computing method are as follows:

Modulation input voltage V _i=U _nThe time, calculate the average F that current transformer is exported data _Max+, modulation input voltage V _i=-U _nThe time, calculate the average F that current transformer is exported data _Max-, U wherein _nThe half-wave voltage of optical fiber current mutual inductor integrated optics chip.The range upper limit I of optical fiber current mutual inductor _Max-With lower limit I _Max+Computing formula as follows:

K _IOC*(F _max+/K)=(4NV)*I _max+ （17）

K _IOC*(F _max-/K)=(4NV)*I _max- （18）

Wherein, K _IOCBe the fixed proportion constant, N is the optical fiber number of turn, and V is the German number of Wei Er.

The scale factory non-linearity degree Kn computing method of optical fiber current mutual inductor are as follows:

Represent the optical fiber current mutual inductor input/output relation with fitting a straight line, as follows:

${\hat{F}}_j=K\·V_j+F_0---\left(19\right)$

By formula (20) calculate the nonlinearity α of optical fiber current mutual inductor output characteristics _j:

${\mathrm{\α}}_j=\frac{{\hat{F}}_j-F_j}{\left|F_m\right|}---\left(20\right)$

Wherein, F _mWhen equaling half-wave voltage for modulation voltage, the maximal value of optical fiber current mutual inductor output.

By formula (21) calculate scale factory non-linearity degree K _m:

K _n＝max|α _j| （21）

The constant multiplier asymmetry K α computing method of optical fiber current mutual inductor are as follows:

Obtain respectively positive voltage, reversal voltage scope inner fiber current transformer constant multiplier and mean value thereof, calculate constant multiplier asymmetry K _α:

$K_{\mathrm{\α}}=\frac{|K_{(+)}-K_{(-)}|}{\stackrel{\‾}{K}}---\left(22\right)$

$\stackrel{\‾}{K}=\frac{K_{(+)}+K_{(-)}}{2}---\left(23\right)$

The constant multiplier repeatability Kr computing method of optical fiber current mutual inductor are as follows:

Repeat (more than 6 times) measuring fiber current transformer constant multiplier Q time, optical fiber current mutual inductor shutdown certain hour between per twice test, and be cooled to room temperature.

By formula (24) calculate constant multiplier repeatability K _r:

$K_r=\frac{1}{\stackrel{\‾}{K}}{\left[\frac{1}{(Q-1)}\underset{i=1}{\overset{Q}{\mathrm{\Σ}}}{(K_i-\stackrel{\‾}{K})}^2\right]}^{\frac{1}{2}}---\left(24\right)$

Claims (1)

1. optical fiber current mutual inductor dynamic property scaling method based on voltage modulated is characterized in that the method may further comprise the steps:

1) the electrooptical modulation signal input part with three optical fiber current mutual inductors links to each other with the voltage signal output end of a phase modulation voltage controller, and the signal output part of optical fiber current mutual inductor links to each other with the data recording device;

2) voltage of control phase modulation voltage controller output null value, the output sequence of values of record three optical fiber current mutual inductors this moment respectively, and the average that seeks out sequence of values is respectively F10, F20, F30;

3) according to the half-wave voltage parameter of integrated optics chip in the optical fiber current mutual inductor, get Δ U=(U _n)/n, described Un is the half-wave voltage value of integrated optics chip, n is the integer greater than 5, regulate the phase modulation voltage controller and export successively, Δ U initial take 0.0V and be incremental change, until be incremented to the half-wave voltage parameter of integrated optics chip, forms the contact potential series of n magnitude of voltage composition, be 0.0V, Δ U, 2 Δ U ... U _nCorresponding different modulating voltage value, record respectively three optical fiber current mutual inductors output numerical value equal value sequence for F110, F120 ... F1n0 }, and F210, F220 ... F2n0 } and F310, F320 ... F3n0 }; Then, the equal value sequence of described three optical fiber current mutual inductors output numerical value is deducted respectively described step 2) in the average F10 of optical fiber current mutual inductor output numerical value of record, F20, F30, namely obtain the nothing zero inclined to one side average sequence { F11 of the output data of three optical fiber current mutual inductors under difference control magnitude of voltage, F12 ... F1n }, { F21, F22, F2n } and F31, F32 ... F3n };

4) after being closed, optical fiber current mutual inductor restarts again, with the positive and negative switching of the output voltage of phase modulation voltage controller, then controlling output voltage is null value, record respectively the output sequence of values of three optical fiber current mutual inductors this moment, and the average that seeks out sequence of values is respectively NF10, NF20, NF30;

5) the reverse voltage sequence that the output of control phase modulation voltage controller is opposite with contact potential series polarity in the described step 3), amplitude equates, the average of the output numerical value when recording respectively the corresponding different voltage value of three unjacketed optical fiber current transformers is { NF110, NF120, NF1n0 }, { NF210, NF220, NF2n0 }, NF310, NF320 ... NF3n0 }; Then, the equal value sequence with described three optical fiber current mutual inductors output numerical value deducts respectively the average NF10 that the optical fiber current mutual inductor that records in the described step 4) is exported numerical value, NF20, NF30, namely obtain partially average sequence { NF11 of nothing zero that three optical fiber current mutual inductors oppositely control the output data under the magnitude of voltage in difference, NF12 ... NF1n }, { NF21, NF22 ... NF2n }, { NF31, NF32 ... NF3n };

The nothing zero of the output numerical value during the corresponding different voltage value of three optical fiber current mutual inductors that 6) obtains according to described step 3) is average sequence { F11 partially, F12, ... F1n }, { F21, F22, ... F2n }, { F31, F32, ... F3n }, the nothing zero of the output numerical value during with the corresponding different voltage value of three optical fiber current mutual inductors of step 5) record is average sequence { NF11 partially, NF12 ... NF1n }, { NF21, NF22 ... NF2n }, { NF31, NF32, ... NF3n }, go out the range of optical fiber current mutual inductor by the half-wave voltage parameter value calculation of described integrated optics chip, calculate the constant multiplier of optical fiber current mutual inductor according to the constant multiplier computing formula, the scale factory non-linearity degree, constant multiplier asymmetry and constant multiplier repeatability.

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