CN104882181A - Delay eliminating method for signal of self-powered vanadium detector based on H-infinity filtering - Google Patents

Abstract

The invention discloses a delay eliminating method for a signal of a self-powered vanadium detector based on H-infinity filtering. The delay eliminating method sequentially comprises the following steps of 1, establishing a nuclear reaction model of vanadium and thermal neutrons; 2, establishing a discrete state equation corresponding to the nuclear reaction model through direct transform; 3, determining the instant response share of the current of the self-powered vanadium detector; and 4, carrying out delay elimination on a current signal of the self-powered vanadium detector by using a H-infinity filter. When the delay eliminating method is applied, a current signal of a self-powered vanadium neutron detector can be subjected to delay elimination, and noise can also be effectively inhibited, so that the self-powered vanadium neutron detector can also be normally used under the instantaneous condition of a reactor; in addition, due to the adoption of the H-infinity filter, the statistical property of an external disturbance input signal is not needed to be known in advance during delay elimination.

Description

Based on the vanadium self-powered detector signal delay removing method of H ∞ filtering

Technical field

The present invention relates to the treatment technology of vanadium self-power neutron detector signal in advanced reactor core measuring system (nuclear reactor power is distributed in line monitoring system) heap used, specifically based on the vanadium self-powered detector signal delay removing method of H ∞ filtering.

Background technology

As the vanadium self-power neutron detector of detector in advanced reactor core measuring system heap, there is β and to decay generation current in the secondary nucleic that its sensitive material vanadium and neutron reaction produce, under stable situation, this size of current is directly proportional to position flux, therefore can know its position neutron flux by inference by measuring vanadium self-powered detector.Because such detector current principal ingredient is produced by secondary nucleic β decay, in reactor transient state situation (situation of neutron-flux level change), such detector current can not reflect the change of flux level in real time, but having certain delay, delay time parameter decays consistent with the β of secondary nucleic.Therefore, utilizing vanadium self-power neutron detector to make the advanced reactor core measuring system of neutron measurement device, in order to ensure the accuracy of neutron flux measurement, needing the current signal visiting device to vanadium self-sufficiency to do to postpone Processing for removing.

Owing to being always attended by noise (process noise and measurement noises) in the measuring process of reality, utilizing direct mathematical inversion method to do to postpone elimination can amplify detector current signal noise, is maximumly amplified to 20 times, the precision that impact is measured.Therefore, in delay Processing for removing process, the amplification of effective restraint speckle is needed.

The elimination being applied to vanadium self-powered detector signal delay at present mainly realizes based on Kalman filter, must suppose that the external disturbance input signal of system is a white noise signal with known statistical property during its application, when the statistical property of input signal is difficult to obtain, the method is just difficult to application.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, provide a kind of vanadium self-powered detector signal delay removing method based on H ∞ filtering, delay Processing for removing can be carried out to the current signal of vanadium self-power neutron detector during its application, and can effective restraint speckle, vanadium self-power neutron detector also can normally be used when reactor transient condition, and owing to present invention employs H ∞ wave filter, without the need to knowing the statistical property of external disturbance input signal in advance when doing to postpone to eliminate.

The present invention solves the problem and is achieved through the following technical solutions: based on the vanadium self-powered detector signal delay removing method of H ∞ filtering, comprise the following steps:

Step 1, set up the nuclear reaction model of vanadium and thermal neutron:

Under reactor transient condition, the change of flux causes the change of vanadium self-power neutron detector electric current and asynchronous, and the latter has certain delayed compared with the former, the concrete formula describing above-mentioned reaction is as follows:

$\left\{\begin{array}{c}\frac{d}{\mathrm{dt}}{N}_{51}\left(t\right)=-N_{51}\left(t\right){\mathrm{\σ}}_{51}\mathrm{\Φ}\left(t\right)\\ \frac{d}{\mathrm{dt}}{N}_{52}\left(t\right)=N_{51}\left(t\right){\mathrm{\σ}}_{51}\mathrm{\Φ}\left(t\right)-{\mathrm{\λ}}_{52}{N}_{52}\left(t\right)\\ I\left(t\right)=K_{\mathrm{pv}}{N}_{51}\left(t\right){\mathrm{\σ}}_{51}\mathrm{\Φ}\left(t\right)+K_{\mathrm{gv}}{\mathrm{\λ}}_{52}{N}_{52}\left(t\right)\end{array}\right.---\left(1\right)$

Wherein, Φ (t) is neutron flux, N ₅₁(t) be ⁵¹the cuclear density of V, N ₅₂(t) be ⁵²the cuclear density of V, σ ₅₁for ⁵¹the neutron-absorption cross-section of V, λ ₅₂for ⁵²the decay constant of V, I (t) is vanadium self-powered detector output current, K _pvfor the sensitivity of transient member, K _gvfor the sensitivity of transient member;

Formula (1) distortion is obtained following equation:

$\frac{\∂m_1\left(t\right)}{\∂t}=-\mathrm{an}\left(t\right)---\left(2\right)$

$\frac{\∂m_2\left(t\right)}{\∂t}=-\mathrm{an}\left(t\right)-\mathrm{\λ}{m}_2---\left(3\right)$

I(t)＝cn(t)+λm ₂(t) (4)

Wherein, m ₁(t), m ₂t () represents respectively ⁵¹v, ⁵²the storage of V, c is the instantaneous share of electric current, and a is the β decay share of electric current;

Step 2, employing Direct Transform obtain discrete state equations corresponding to nuclear reaction model:

Make J _a(t)=λ m ₂t () substitutes in formula (2), formula (3) and formula (4), the ordinary differential equation of continuous time is directly carried out discretize, and adds noise item, obtain following discrete state equations:

$X(k+1)=\left[\begin{array}{cc}{e}^{-\mathrm{\λ}\·\mathrm{Ts}}& (1-e^{-\mathrm{\λ}.\·\mathrm{Ts}})\\ 0& 1\end{array}\right]\·X\left(k\right)+\left[\begin{array}{c}0\\ 1\end{array}\right]W---\left(k\right)---\left(5\right)$

I(k)＝[1 c]·X(k)+[1]·V(k) (6)

n(k)＝[0 1]·X(k) (7)

Wherein, $X\left(k\right)=\left[\begin{array}{c}{J}_a\left(k\right)\\ n\left(k\right)\end{array}\right]$

Initial value is

$X\left(0\right)=\left[\begin{array}{c}{J}_a\left(0\right)\\ n\left(0\right)\end{array}\right]=\left[\begin{array}{c}I\left(0\right)\\ I\left(0\right)\end{array}\right]---\left(8\right)$

Step 3, determine the transient response share of vanadium self-powered detector electric current;

Step 4, utilize H ∞ wave filter to vanadium self-powered detector current signal do postpone eliminate:

For a discrete control procedure system, this system can describe with a state equation:

$\begin{array}{c}x(k+1)=\mathrm{Ax}\left(k\right)+\mathrm{Bw}\left(k\right)\\ y\left(k\right)=\mathrm{Cx}\left(k\right)+\mathrm{Sw}\left(k\right)\\ z\left(k\right)=\mathrm{Lx}\left(k\right)\end{array}---\left(9\right)$

Wherein, the n dimension state vector that x (k) is kth time sampled point, w (k) contains systematic procedure noise and systematic observation white noise, and y (k) is the measured value of kth time sampled point, z (k) 1 ties up and waits to ask vector, and L is that l*n ties up matrix;

Assuming that system is asymptotically stable, then to given constant γ >0, require design one asymptotically stable full rank linear filter

$\begin{array}{c}\hat{x}(k+1)=A_f\hat{x}\left(k\right)+B_f\hat{y}\left(k\right)\\ \hat{z}\left(k\right)=C_f\hat{x}\left(k\right)\end{array}---\left(10\right)$

There is a H ∞ wave filter in system, and if only if, and following LMI is set up

$\left[\begin{array}{cccccc}Z& Z& \mathrm{ZA}& \mathrm{ZA}& \mathrm{ZB}& 0\\ *& Y& \mathrm{YA}+\mathrm{FC}+Q& \mathrm{YA}+\mathrm{FC}& \mathrm{YB}+\mathrm{FD}& 0\\ *& *& Z& Z& 0& L^{\′}-G^{\′}\\ *& *& *& Y& 0& L^{\′}\\ *& *& *& *& I& 0\\ *& *& *& *& *& {\mathrm{\γ}}^{2}I\end{array}\right]>0---\left(11\right)$

Wherein Y, Z are symmetric positive definite matrix to be solved, and Q, G, F are general matrix to be solved;

After obtaining above-mentioned matrix, the correlation matrix of H ∞ wave filter is expressed as follows:

A _f＝-Y ^-1Q(I-Y ^-1Z) ^-1,B _f＝-Y ^-1F,C _f＝G(I-Y ^-1Z) ^-1(12)

For vanadium self-powered detector, by the homography in the known equation of its discrete state equations (9) be:

$A=\left[\begin{array}{cc}{e}^{-\mathrm{\λ}\·\mathrm{Ts}}& (1-e^{-\mathrm{\λ}\·\mathrm{Ts}})\\ 0& 1\end{array}\right]$

$B=\left[\begin{array}{cc}0& 0\\ 1& 0\end{array}\right]$

C＝[1 c]

D＝[0 1]

L＝[0 1]

By solving LMI (11), H ∞ electric-wave filter matrix A can be obtained _f, B _f, C _f, thus can obtain by following steps the detector current value eliminated and postpone rear any time:

By initial current measured value can obtain $\hat{x}\left(0\right)=\left[\begin{array}{c}\hat{y}\left(0\right)\\ \hat{y}\left(0\right)\end{array}\right],$ Initial 0 moment postpones to eliminate after-current value $\hat{z}\left(0\right)=C_f\hat{x}\left(0\right);$

For any k+1 (k=0,1 ...) and the moment, and the k+1 moment postpone eliminate after current value be $\hat{z}(k+1)=C_f\hat{x}(k+1).$

Nuclear reaction model is the basis that filter application carries out postponing to eliminate, and the present invention is by first principle, and step one derives variable mathematics model continuous time corresponding to this physical process of vanadium self-powered detector generation signal.Current signal due to detector is all obtained by discrete sampling, and the continuous state equation that step 1 is set up by step 2 is converted to discrete state equations.

H ∞ Filter Principle is utilized when the present invention applies, in delay elimination process, can the amplification of restraint speckle effectively, noise suppression effect is better, carryover effects can be deteriorated gradually, therefore, needs suitable regulating parameter to make delay eradicating efficacy and squelch reach optimum balance when the present invention applies.

Vanadium self-powered detector transient response share c generally can be estimated by theory, but do not mate the decline that will cause filter effect between theoretical assessment with actual value, in order to determine transient response share c exactly, further, described step 3 determines that the transient response share of vanadium self-powered detector electric current specifically comprises the steps: in the reactor start-up Physical Experiment stage, power step is formed by lifting/lowering reactor capability, record corresponding ex-core detector signal measured value and vanadium self-powered detector signal measured value, wherein, ex-core detector can the change of transient response neutron flux, corresponding measured value can think real neutron flux, by the given N number of different transient response share predicted value of theoretical value of adjustment transient response share, again ex-core detector signal measured value is substituted into discrete state equations, N group vanadium self-powered detector signal theory value can be obtained, theoretical value and vanadium self-powered detector signal measured value are compared, gets certain best group theoretical value corresponding transient response share predicted value of wherein matching degree for subsequent delay and eliminate the transient response share adopted.

When the neutron-flux density needing detection compared with great dynamic range, also need the current signal detecting great dynamic range accordingly, and this problem just concentrates on analog to digital converter.In order to adapt to the quantification of the electric current of great dynamic range, the analog to digital converter sampling step resistance of vanadium self-powered detector, when current signal is in wide variation, will there is the conversion of resistance gear in analog to digital converter.Because each gear does not mate completely, the switching between each gear can cause the sudden change being similar to step of output signal.

The sudden change component that gearshift causes can seriously be amplified after entering and postponing cancellation module, the step in time domain is suddenlyd change and is seriously amplified, affect the quality (serious distortion of Mutational part signal) that final signal postpones elimination.In the gearshift time period, the change of signal, primarily of gearshift sudden change contribution, comparatively speaking, changes by neutron-flux density the current signal caused and changes and can ignore.

In order to process the sign mutation problem that gear shift causes, further, when there being gearshift, also comprise and by following signal processing method, original signal being processed: in gear shift region, suppose that neutron flux remains unchanged, then the anti-current signal pushing away neutron-flux density and produce, then subtract each other with detector actual output current, obtain gearshift sudden change component; Outside gear shift region, detector output current deducts gearshift sudden change component, obtains the current signal that neutron-flux density produces, and then carries out delay Processing for removing to this current signal.

Further, described gear shift zone design structure is as follows:

(k in gear shift region ₁≤ k≤k ₂), suppose that neutron-flux density is constant, then have:

n(k+1)＝n(k) (13)

J _a(k+1)＝e ^-λ·TsJ _a(k)+(1-e ^-λ·Ts)n(k) (14)

Instead can release vanadium self-powered detector current signal is:

I(k+1)＝J _a(k+1)+cn(k+1) (15)

By the anti-electric current (15) that pushes away as detector actual output current, then carry out delay and eliminate;

At gear shift border zone time k ₂place, the current offset amount that gear shift causes can be estimated by following formula:

$D=I\left(k_2\right)-\hat{y}\left(k_2\right)---\left(16\right)$

Wherein, represent at k ₂the detector actual output current in moment;

Outside gear shift region, detector actual output current is added the current offset amount that gear shift that above formula (16) represents causes, obtain the current signal that neutron-flux density produces, and then delays elimination is carried out to this current signal.

In sum, the present invention has following beneficial effect: the overall operation of (1) the present invention is simple, be convenient to realize, delay Processing for removing can be carried out to the current signal of vanadium self-power neutron detector, and can effective restraint speckle, vanadium self-power neutron detector also can normally be used when reactor transient condition; The present invention is based on H ∞ wave filter to realize, also can normal use when the statistical property of input signal cannot obtain; When the present invention applies, design of filter is converted into corresponding linear MATRIX INEQUALITIES to calculate, convenient calculating, can use the LMI Toolbox of Matlab to solve easily.

(2) problem is eliminated in the delay that the invention solves vanadium self-power neutron detector signal in advanced reactor core measuring system (nuclear reactor power is distributed in line monitoring system) heap used.Delay is eliminated, level and smooth, noise reduction process to utilize H ∞ wave filter to carry out vanadium self-power neutron detector signal, by suitably choosing H ∞ filter parameter, can be good at the optimum balance reaching signal delay eradicating efficacy and noise suppression effect.The present invention can ensure that vanadium self-powered detector current signal is directly used in the follow-up link of advanced reactor core measuring system, and does not lose accuracy.

(3) the present invention carries out delay Processing for removing to the current signal of vanadium self-power neutron detector, the response time (during step variations of flux, signal recuperation to steady-state current 90% needed for time) in 2 ~ 10 seconds.

(4) the present invention postpones in elimination process to the current signal of vanadium self-power neutron detector, carry out noise reduction process to measurement current signal, noise enlargement factor (postponing the ratio of the electric current relative error after Processing for removing and noise) suppresses at 1 ~ 8 times.

(5) the present invention can effectively process because hardware shifts gears the step caused to the impact postponing eradicating efficacy.

Accompanying drawing explanation

Fig. 1 is vanadium self-power neutron detector structural drawing of the present invention;

Fig. 2 is the processing flow chart of the present invention's specific embodiment;

Fig. 3 is vanadium and thermal neutron nuclear reaction figure.

Mark and corresponding parts title in accompanying drawing: 1-emitter, 2-insulation course, 3-collector, 4-wire, 5-containment vessel, 6-insulated cable, 7-current line, 8-tourism background trend line, 9-sealed tube, 10-current output terminal.

Embodiment

Below in conjunction with embodiment and accompanying drawing, detailed description is further done to the present invention, but embodiments of the present invention are not limited thereto.

Embodiment:

Vanadium self-power neutron detector structural drawing as shown in Figure 1, wherein the parts title of each sequence number corresponds to: 1-emitter, 2-insulation course, 3-collector; 4-wire, 5-containment vessel, 6-insulated cable, 7-current line; 8-tourism background trend line, 9-sealed tube, 10-current output terminal.The characterisitic parameter of this vanadium self-power neutron detector is: λ ₁=ln2/42.3s ^-1=0.016386s ^-1, λ ₂=ln2/4.34/60s ^-1=0.00266186s ^-1, c=0.06, a ₁=0.879, a ₂=0.061.Fig. 3 is vanadium and neutron nuclear reaction principle procedure chart, in the course of reaction of Fig. 3, adopts the device of Fig. 1 to measure.As shown in Figure 2, eliminate the method for vanadium self-powered detector signal delay based on H ∞ filtering, comprise the following steps of carrying out successively: step 1, set up the nuclear reaction model of vanadium and thermal neutron; Step 2, employing Direct Transform set up discrete state equations corresponding to nuclear reaction model; Step 3, determine the transient response share of vanadium self-powered detector electric current; Step 4, utilize H ∞ wave filter to vanadium self-powered detector current signal do postpone eliminate.

The concrete implementation step that the present embodiment sets up the nuclear reaction model of vanadium and thermal neutron is as follows: under reactor transient condition, the change of flux causes the change of vanadium self-power neutron detector electric current and asynchronous, the latter has certain delayed compared with the former, the concrete formula describing above-mentioned reaction is as follows:

$\left\{\begin{array}{c}\frac{d}{\mathrm{dt}}{N}_{51}\left(t\right)=-N_{51}\left(t\right){\mathrm{\σ}}_{51}\mathrm{\Φ}\left(t\right)\\ \frac{d}{\mathrm{dt}}{N}_{52}\left(t\right)=N_{51}\left(t\right){\mathrm{\σ}}_{51}\mathrm{\Φ}\left(t\right)-{\mathrm{\λ}}_{52}{N}_{52}\left(t\right)\\ I\left(t\right)=K_{\mathrm{pv}}{N}_{51}\left(t\right){\mathrm{\σ}}_{51}\mathrm{\Φ}\left(t\right)+K_{\mathrm{gv}}{\mathrm{\λ}}_{52}{N}_{52}\left(t\right)\end{array}\right.---\left(1\right)$

Wherein, Φ (t) is neutron flux, N ₅₁(t) be ⁵¹the cuclear density of V, N ₅₂(t) be ⁵²the cuclear density of V, σ ₅₁for ⁵¹the neutron-absorption cross-section of V, λ ₅₂for ⁵²the decay constant of V, I (t) is vanadium self-powered detector output current, K _pvfor the sensitivity of transient member, K _gvfor the sensitivity of transient member;

Formula (1) distortion is obtained following equation:

$\frac{\∂m_1\left(t\right)}{\∂t}=-\mathrm{an}\left(t\right)---\left(2\right)$

$\frac{\∂m_2\left(t\right)}{\∂t}=-\mathrm{an}\left(t\right)-\mathrm{\λ}{m}_2---\left(3\right)$

I(t)＝cn(t)+λm ₂(t) (4)

Wherein, m ₁(t), m ₂t () represents respectively ⁵¹v, ⁵²the storage of V, c is the instantaneous share of electric current, and a is the β decay share of electric current.

The concrete implementation step that the present embodiment employing Direct Transform sets up discrete state equations corresponding to nuclear reaction model is as follows:

Make J _a(t)=λ m ₂t () substitutes in formula (2), formula (3) and formula (4), the ordinary differential equation of continuous time is directly carried out discretize, and adds noise item, obtain following discrete state equations:

$X(k+1)=\left[\begin{array}{cc}{e}^{-\mathrm{\λ}\·\mathrm{Ts}}& (1-e^{-\mathrm{\λ}.\·\mathrm{Ts}})\\ 0& 1\end{array}\right]\·X\left(k\right)+\left[\begin{array}{c}0\\ 1\end{array}\right]W---\left(k\right)---\left(5\right)$

I(k)＝[1 c]·X(k)+[1]·V(k) (6)

n(k)＝[0 1]·X(k) (7)

Wherein, $X\left(k\right)=\left[\begin{array}{c}{J}_a\left(k\right)\\ n\left(k\right)\end{array}\right]$

Initial value is

$X\left(0\right)=\left[\begin{array}{c}{J}_a\left(0\right)\\ n\left(0\right)\end{array}\right]=\left[\begin{array}{c}I\left(0\right)\\ I\left(0\right)\end{array}\right]---\left(8\right).$

The concrete implementation step of the transient response share of the present embodiment determination vanadium self-powered detector electric current is as follows: in the reactor start-up Physical Experiment stage, form power step by lifting/lowering reactor capability, record corresponding ex-core detector signal measured value and vanadium self-powered detector signal measured value.Ex-core detector can the change of transient response neutron flux, and corresponding measured value can think real neutron flux.By the given N number of different transient response share predicted value of theoretical value of adjustment transient response share, again ex-core detector signal measured value is substituted into discrete state equations, N group vanadium self-powered detector signal theory value can be obtained, theoretical value and vanadium self-powered detector signal measured value are compared, gets certain best group theoretical value corresponding transient response share predicted value of wherein matching degree for subsequent delay and eliminate the transient response share adopted.

The concrete implementation step that the present embodiment utilizes H ∞ wave filter to do to postpone to eliminate to vanadium self-powered detector current signal is as follows:

For a discrete control procedure system, this system can describe with a state equation:

$\begin{array}{c}x(k+1)=\mathrm{Ax}\left(k\right)+\mathrm{Bw}\left(k\right)\\ y\left(k\right)=\mathrm{Cx}\left(k\right)+\mathrm{Sw}\left(k\right)\\ z\left(k\right)=\mathrm{Lx}\left(k\right)\end{array}---\left(8\right)$

Wherein, the n dimension state vector that x (k) is kth time sampled point, w (k) contains systematic procedure noise and systematic observation white noise, and y (k) is the measured value of kth time sampled point, z (k) 1 ties up and waits to ask vector, and L is that l*n ties up matrix;

Assuming that system is asymptotically stable, then to given constant γ >0, require design one asymptotically stable full rank linear filter

$\begin{array}{c}\hat{x}(k+1)=A_f\hat{x}\left(k\right)+B_f\hat{y}\left(k\right)\\ \hat{z}\left(k\right)=C_f\hat{x}\left(k\right)\end{array}---\left(9\right)$

There is a H ∞ wave filter in system, and if only if, and following LMI is set up

$\left[\begin{array}{cccccc}Z& Z& \mathrm{ZA}& \mathrm{ZA}& \mathrm{ZB}& 0\\ *& Y& \mathrm{YA}+\mathrm{FC}+Q& \mathrm{YA}+\mathrm{FC}& \mathrm{YB}+\mathrm{FD}& 0\\ *& *& Z& Z& 0& L^{\′}-G^{\′}\\ *& *& *& Y& 0& L^{\′}\\ *& *& *& *& I& 0\\ *& *& *& *& *& {\mathrm{\γ}}^{2}I\end{array}\right]>0---\left(10\right)$

Wherein Y, Z are symmetric positive definite matrix to be solved, and Q, G, F are general matrix to be solved;

After obtaining above-mentioned matrix, the correlation matrix of H ∞ wave filter is expressed as follows:

A _f＝-Y ^-1Q(I-Y ^-1Z) ^-1,B _f＝-Y ^-1F,C _f＝G(I-Y ^-1Z) ^-1(11)

For vanadium self-powered detector, by the homography in the known equation of its discrete state equations (8) be:

$A=\left[\begin{array}{cc}{e}^{-\mathrm{\λ}\·\mathrm{Ts}}& (1-e^{-\mathrm{\λ}\·\mathrm{Ts}})\\ 0& 1\end{array}\right]$

$B=\left[\begin{array}{cc}0& 0\\ 1& 0\end{array}\right]$

C＝[1 c]

D＝[0 1]

L＝[0 1]

By solving LMI (11), (12), H ∞ electric-wave filter matrix A can be obtained _f, B _f, C _f, thus can obtain by following steps the detector current value eliminated and postpone rear any time:

By initial current measured value can obtain $\hat{x}\left(0\right)=\left[\begin{array}{c}\hat{y}\left(0\right)\\ \hat{y}\left(0\right)\end{array}\right],$ Initial 0 moment postpones to eliminate after-current value $\hat{z}\left(0\right)=C_f\hat{x}\left(0\right);$

For any k+1 (k=0,1 ...) and the moment, and the k+1 moment postpone eliminate after current value be $\hat{z}(k+1)=C_f\hat{x}(k+1).$

Embodiment 2:

The present embodiment has made following restriction further on the basis of embodiment 1: when there being gearshift, also comprise and by following signal processing method, original signal being processed: in gear shift region, suppose that neutron flux remains unchanged, then the anti-current signal pushing away neutron-flux density and produce, subtract each other with detector actual output current again, obtain gearshift sudden change component; Outside gear shift region, detector output current deducts gearshift sudden change component, obtains the current signal that neutron-flux density produces, and then carries out delay Processing for removing to this current signal.

The gear shift zone design structure of the present embodiment is as follows:

(k in gear shift region ₁≤ k≤k ₂), suppose that neutron-flux density is constant, then have:

n(k+1)＝n(k) (13)

J _a(k+1)＝e ^-λ·TsJ _a(k)+(1-e ^-λ·Ts)n(k) (14)

Instead can release vanadium self-powered detector current signal is:

I(k+1)＝J _a(k+1)+cn(k+1) (15)

By the anti-electric current (15) that pushes away as detector actual output current, then carry out delay and eliminate;

At gear shift border zone time k ₂place, the current offset amount that gear shift causes can be estimated by following formula:

$D=I\left(k_2\right)-\hat{y}\left(k_2\right)---\left(16\right)$

Wherein, represent at k ₂the detector actual output current in moment;

Outside gear shift region, need to carry out on detector actual output current the impact that bias compensation brings to offset gear shift, detector actual output current is added the current offset amount that gear shift that above formula (16) represents causes, obtain the current signal that neutron-flux density produces, and then delay elimination is carried out to this current signal.

The above is only preferred embodiment of the present invention, not does any pro forma restriction to the present invention, every according in technical spirit of the present invention to any simple modification, equivalent variations that above embodiment is done, all fall within protection scope of the present invention.

Claims (4)

1., based on the vanadium self-powered detector signal delay removing method of H ∞ filtering, it is characterized in that: comprise the following steps:

Step 1, set up the nuclear reaction model of vanadium and thermal neutron:

Under reactor transient condition, the change of flux causes the change of vanadium self-power neutron detector electric current and asynchronous, and the latter has certain delayed compared with the former, the concrete formula describing above-mentioned reaction is as follows:

$\left\{\begin{array}{c}\frac{d}{\mathrm{dt}}{N}_{51}\left(t\right)=-N_{51}\left(t\right){\mathrm{\σ}}_{51}\mathrm{\Φ}\left(t\right)\\ \frac{d}{\mathrm{dt}}{N}_{52}\left(t\right)=N_{51}\left(t\right){\mathrm{\σ}}_{51}\mathrm{\Φ}\left(t\right)-{\mathrm{\λ}}_{52}{N}_{52}\left(t\right)\\ I\left(t\right)=K_{\mathrm{pv}}{N}_{51}\left(t\right){\mathrm{\σ}}_{51}\mathrm{\Φ}\left(t\right)+K_{\mathrm{gv}}{\mathrm{\λ}}_{52}{N}_{52}\left(t\right)\end{array}\right.---\left(1\right)$

Wherein, Φ (t) is neutron flux, N ₅₁(t) be ⁵¹the cuclear density of V, N ₅₂(t) be ⁵²the cuclear density of V, σ ₅₁for ⁵¹the neutron-absorption cross-section of V, λ ₅₂for ⁵²the decay constant of V, I (t) is vanadium self-powered detector output current, K _pvfor the sensitivity of transient member, K _gvfor the sensitivity of transient member;

Formula (1) distortion is obtained following equation:

$\frac{{\∂m}_1\left(t\right)}{\∂t}=-\mathrm{an}\left(t\right)---\left(2\right)$

$\frac{{\∂m}_2\left(t\right)}{\∂t}=\mathrm{an}\left(t\right)-\mathrm{\λ}{m}_2\left(t\right)---\left(3\right)$

I(t)＝cn(t)+λm ₂(t) (4)

Wherein, m ₁(t), m ₂t () represents respectively ⁵¹v, ⁵²the storage of V, c is the instantaneous share of electric current, and a is the β decay share of electric current;

Step 2, employing Direct Transform obtain discrete state equations corresponding to nuclear reaction model:

Make J _a(t)=λ m ₂t () substitutes in formula (2), formula (3) and formula (4), the ordinary differential equation of continuous time is directly carried out discretize, and adds noise item, obtain following discrete state equations:

$X(k+1)=\left[\begin{array}{cc}{e}^{-\mathrm{\λ}\·\mathrm{Ts}}& (1-e^{-\mathrm{\λ}\·\mathrm{Ts}})\\ 0& 1\end{array}\right]\·X\left(k\right)+\left[\begin{array}{c}0\\ 1\end{array}\right]W\left(k\right)---\left(5\right)$

I(k)＝[1 c]·X(k)+[1]·V(k) (6)

n(k)＝[0 1]·X(k) (7)

Wherein, $X\left(k\right)=\left[\begin{array}{c}{J}_a\left(k\right)\\ n\left(k\right)\end{array}\right]$

Initial value is

$X\left(0\right)=\left[\begin{array}{c}{J}_a\left(0\right)\\ n\left(0\right)\end{array}\right]=\left[\begin{array}{c}I\left(0\right)\\ I\left(0\right)\end{array}\right]---\left(8\right)$

Step 3, determine the transient response share of vanadium self-powered detector electric current;

Step 4, utilize H ∞ wave filter to vanadium self-powered detector current signal do postpone eliminate:

For a discrete control procedure system, this system can describe with a state equation:

x(k+1)＝Ax(k)+Bw(k)

y(k)＝Cx(k)+Dw(k) (9)

z(k)＝Lx(k)

Wherein, the n dimension state vector that x (k) is kth time sampled point, w (k) contains systematic procedure noise and systematic observation white noise, and y (k) is the measured value of kth time sampled point, z (k) 1 ties up and waits to ask vector, and L is that l*n ties up matrix;

Assuming that system is asymptotically stable, then to given constant γ >0, require design one asymptotically stable full rank linear filter

$\begin{array}{c}\hat{x}(k+1)=A_f\hat{x}\left(k\right)+B_f\hat{y}\left(k\right)\\ \hat{z}\left(k\right)=C_f\hat{x}\left(k\right)\end{array}---\left(10\right)$

There is a H ∞ wave filter in system, and if only if, and following LMI is set up

$\left[\begin{array}{cccccc}Z& Z& \mathrm{ZA}& \mathrm{ZA}& \mathrm{ZB}& 0\\ *& Y& \mathrm{YA}+\mathrm{FC}+Q& \mathrm{YA}+\mathrm{FC}& \mathrm{YB}+\mathrm{FD}& 0\\ *& *& Z& Z& 0& L^{\′}-G^{\′}\\ *& *& *& Y& 0& L^{\′}\\ *& *& *& *& I& 0\\ *& *& *& *& *& {\mathrm{\γ}}^{2}I\end{array}\right]>0---\left(11\right)$

Wherein Y, Z are symmetric positive definite matrix to be solved, and Q, G, F are general matrix to be solved;

After obtaining above-mentioned matrix, the correlation matrix of H ∞ wave filter is expressed as follows:

A _f＝-Y ^-1Q(I-Y ^-1Z) ^-1,B _f＝-Y ^-1F,C _f＝G(I-Y ^-1Z) ^-1(12)

For vanadium self-powered detector, by the homography in the known equation of its discrete state equations (9) be:

$A=\left[\begin{array}{cc}{e}^{-\mathrm{\λ}\·\mathrm{Ts}}& (1-e^{-\mathrm{\λ}\·\mathrm{Ts}})\\ 0& 1\end{array}\right]$

$B=\left[\begin{array}{cc}0& 0\\ 1& 0\end{array}\right]$

C＝[1 c]

D＝[0 1]

L＝[0 1]

By solving LMI (11), H ∞ electric-wave filter matrix A can be obtained _f, B _f, C _f, thus can obtain by following steps the detector current value eliminated and postpone rear any time:

By initial current measured value can obtain $\hat{x}\left(0\right)=\left[\begin{array}{c}\hat{y}\left(0\right)\\ \hat{y}\left(0\right)\end{array}\right],$ Initial 0 moment postpones to eliminate after-current value $\hat{z}\left(0\right)=C_f\hat{x}\left(0\right);$

For any k+1 (k=0,1 ...) and the moment, and the k+1 moment postpone eliminate after current value be $\hat{z}(k+1)=C_f\hat{x}(k+1).$

2. the vanadium self-powered detector signal delay removing method based on H ∞ filtering according to claim 1, it is characterized in that, described step 3 determines that the transient response share of vanadium self-powered detector electric current specifically comprises the steps: in the reactor start-up Physical Experiment stage, power step is formed by lifting/lowering reactor capability, record corresponding ex-core detector signal measured value and vanadium self-powered detector signal measured value, wherein, ex-core detector can the change of transient response neutron flux, and corresponding measured value can think real neutron flux; By the given N number of different transient response share predicted value of theoretical value of adjustment transient response share, again ex-core detector signal measured value is substituted into discrete state equations, N group vanadium self-powered detector signal theory value can be obtained, theoretical value and vanadium self-powered detector signal measured value are compared, gets certain best group theoretical value corresponding transient response share predicted value of wherein matching degree for subsequent delay and eliminate the transient response share adopted.

3. the vanadium self-powered detector signal delay removing method based on H ∞ filtering according to claim 1 and 2, it is characterized in that, when there being gearshift, also comprise and by following signal processing method, original signal being processed: in gear shift region, suppose that neutron flux remains unchanged, then the anti-current signal pushing away neutron-flux density and produce, then subtract each other with detector actual output current, obtain gearshift sudden change component; Outside gear shift region, detector output current deducts gearshift sudden change component, obtains the current signal that neutron-flux density produces, and then carries out delay Processing for removing to this current signal.

4. the vanadium self-powered detector signal delay removing method based on H ∞ filtering according to claim 3, it is characterized in that, described gear shift zone design structure is as follows:

(k in gear shift region ₁≤ k≤k ₂), suppose that neutron-flux density is constant, then have:

n(k+1)＝n(k) (13)

J _a(k+1)＝e ^-λ·TsJ _a(k)+(1-e ^-λ·Ts)n(k) (14)

Instead can release vanadium self-powered detector current signal is:

I(k+1)＝J _a(k+1)+cn(k+1) (15)

By the anti-electric current (15) that pushes away as detector actual output current, then carry out delay and eliminate;

At gear shift border zone time k ₂place, the current offset amount that gear shift causes can be estimated by following formula:

$D=I\left(k_2\right)-\hat{y}\left(k_2\right)---\left(16\right)$

Wherein, represent at k ₂the detector actual output current in moment;

Outside gear shift region, detector actual output current is added the current offset amount that gear shift that above formula (16) represents causes, obtain the current signal that neutron-flux density produces, and then delays elimination is carried out to this current signal.