CN104916490A - Permanent-magnet vacuum circuit breaker switching-on/off control method and permanent-magnet vacuum circuit breaker switching-on/off device - Google Patents

Abstract

The invention provides a permanent-magnet vacuum circuit breaker switching-on/off control device and a permanent-magnet vacuum circuit breaker switching-on/off method. A charge and discharge control unit charges and discharges an energy storage capacitor according to charge and discharge signals from a core control unit, and feeds the real-time voltage and current of the energy storage capacitor back to the core control unit. Before switching-on/off operation, the core control unit determines a PWM reference curve of the operation according to the current voltage value of the capacitor, and further determines the PWM duty cycle reference value corresponding to each moment of time in the switching-on/off process. The permanent-magnet vacuum circuit breaker switching-on/off control device and the permanent-magnet vacuum circuit breaker switching-on/off method provided by the invention have the advantage that the ripple of output current of the controller is reduced effectively, the output quality of current is improved, and the output current is closer to reference current on the premise of not increasing the burden on the system. By using the control device in switching-on/off, the stability of switching-on/off time is maintained, and the reliability of permanent-magnet vacuum circuit breaker switching-on/off is improved.

Description

A kind of control method of permanent magnetic vacuum breaker divide-shut brake and device

Technical field

The present invention relates to a kind of control device of permanent magnetic vacuum breaker divide-shut brake, also relate to a kind of control method of permanent magnetic vacuum breaker divide-shut brake.

Background technology

At present, permanent magnetic vacuum breaker generally adopts the control method of open loop, and namely circuit breaker is when carrying out divide-shut brake, and controller only sends an I/O signal, thus driving power break-over of device a period of time completes divide-shut brake process.Under open loop situations, the motion process of contact of breaker is not controlled, and the time of divide-shut brake can occur larger fluctuation with storage capacitor capacity and the impact of electric capacity initial voltage variation, in case of a fault, even may occur the situation that coil is damaged.Under higher operation voltage, carry out breaking-closing operating can make movement velocity unshakable in one's determination increase, and makes contact bear larger impulsive force, causes mechanism to be shortened useful life, and moving contact may be made to occur repeatedly to bounce, and impact closes reliability.If the patent No. is the patent of invention of CN201210461913.4, publication date is on February 13rd, 2013, disclose a kind of vacuum circuit-breaker control method based on coil current and device realization (patent 1), the control strategy of applied current closed loop realizes the control to vacuum circuit-breaker, namely by controlling the method that the coil current of permanent magnet mechanism and given current curve are consistent, improve the kinetic characteristic of moving contact, and ensure that at the same temperature, the closing time of circuit breaker is not with the impact of electric capacity initial voltage and capacitance, the closing time scatter under same temperature is made to reach ± 0.3ms.The patent No. is the patent of invention of CN201310088167.3, publication date is on September 18th, 2013, disclose a kind of VVVE permanent magnetic vacuum breaker shutting-brake control method (patent 2), on the basis of patent 1, achieve the coarse adjustment to the breaker closing time and fine setting, and provide a kind of computational methods of current reference curve, achieve the control to the breaker closing time very well.Two patents all realize by controlling switching current curve, its control core is all allow controller output closer to the electric current of preset reference current curve, can say that patent 1 solves basic control method problem, how patent 2 determines reference curve if solving, thus realize the problem that closing time regulates and combined floodgate characteristic adjusts.Their realization is all realize with modified model hysteresis control method thereof, and therefore the degree of closeness of controller output current and reference curve directly will affect precision and the reliability of control.To in the combined floodgate testing process of 27.5kV bistable permanent-magnet vacuum circuit breaker, because load is heavier, there is electric current curve of output as shown in Figure 1.Abscissa is time value in FIG, and unit is ms, and ordinate is AD sampled value.

Summary of the invention

Technical problem to be solved by this invention is the deficiency overcoming above-mentioned prior art, provides a kind of control device and method of permanent magnetic vacuum breaker divide-shut brake.

The main technical schemes adopted according to the control method of a kind of permanent magnetic vacuum breaker divide-shut brake provided by the invention is: adopt mixed type PWM control technology, by fixed-frequency PWM control technology and Hysteresis control combine with technique, under the prerequisite not increasing system burden, improve the quality of controller output current, comprise the following steps

1) computation PWM is with reference to base value, under determining to correspond to specific divide-shut brake voltage, and the reference PWM base value that in divide-shut brake process, each moment is corresponding;

2) 4 medium filterings are utilized to calculate the real-time current value in each moment in divide-shut brake process;

3) utilize hysteresis control method thereof to calculate real-time current increment, and be according to setting the actual PWM duty ratio exported as R with increment ₁and R ₂.

The control method of permanent magnetic vacuum breaker divide-shut brake provided by the invention also can have following attached technical characteristic:

PWM with reference to formula in the computational methods of base value is, r=R _s+ n (R _e-R _s)/N,

In formula, n is in divide-shut brake process, and from the n-th sampling instant that moving contact motion starts, N is the sampling number completing the moment in divide-shut brake process from the moving contact initiating moment to divide-shut brake, and r is the reference PWM value of the n-th sampling instant, R _sfor the PWM duty ratio of divide-shut brake initial time, R _gfor the duty ratio of divide-shut brake end moment PWM, and:

$\left\{\begin{array}{c}{R}_s=1/\mathrm{\β}\\ R_e=\mathrm{\α}/\sqrt{{\mathrm{\β}}^2+({\mathrm{\α}}^2-1)/\mathrm{\γ}}\end{array}\right.$

When in formula, α is for obtaining reference curve, perform the divide-shut brake order end moment, the ratio of capacitance voltage and initial voltage, when β is normal divide-shut brake, the ratio of actual capacitance initial voltage and electric capacity initial voltage when obtaining reference curve, γ is the capacity chosen of actual divide-shut brake and the ratio of capacitance when obtaining reference curve.

Based on the reference PWM duty ratio r of the n-th sampling instant, the upper limit PWM value R that the calculating corresponding moment should export ₁, and lower limit PWM value R ₂, R ₁and R ₂that chooses should follow two principles:

1) be R in duty ratio ₁time, guarantee that controller output current is greater than reference current;

2) be R in duty ratio ₂time, guarantee that controller output current is less than reference current.

In whole divide-shut brake process, N is the sampling number of AD in whole divide-shut brake process, and n is the n-th sampling instant from start time of closing a floodgate.

After determining α value, under the capacitance that given γ value is corresponding, calculate the voltage reference value that the maximum reference variation amount of PWM is corresponding, wherein:

${\mathrm{\β}}_0=\sqrt{\frac{1-{\mathrm{\α}}^2}{\mathrm{\γ}(1-{\mathrm{\α}}^{2/3})}}$

β ₀be the voltage coefficient value that maximum PWM variable quantity is corresponding.

The main technical schemes adopted according to the control device of a kind of permanent magnetic vacuum breaker divide-shut brake provided by the invention is: comprise charge-discharge control unit, IGBT power stage unit, Phototube Coupling unit, analog signal conditioner unit and key control unit,

Storage capacitor real-time voltage and current feedback to energy storage capacitor discharge and recharge, and are given described key control unit according to the discharge and recharge signal from described key control unit by charge-discharge control unit;

Before breaking-closing operating, described key control unit, according to current capacitance voltage value, determines this PWM reference curve operated, thus determines the PWM duty cycle reference value that in divide-shut brake process, each moment is corresponding;

When carrying out breaking-closing operating, described Phototube Coupling unit carries out medium filtering and calculating current increment to the electric current gathered;

Key control unit, according to the duty cycle reference value of current time PWM, triggers IGBT by IGBT control unit and completes corresponding action, reach the object controlling electric current.

The control device of permanent magnetic vacuum breaker divide-shut brake provided by the invention also can have following attached technical characteristic:

Described control device adopts the control mode of coil current closed loop, and key control unit is by hysteresis control method thereof calculating current increment.

Described key control unit should have PWM controlling functions.

The current increment that described key control unit calculates according to hysteresis control method thereof, and export different dutyfactor values according to current increment, reach the object of Current adjustment.

Control device Real-Time Monitoring capacitance voltage, and before operation, calculate the reference value of PWM according to voltage, and in divide-shut brake control procedure, export different duty, carry out Current adjustment.

The beneficial effect adopting the control device of permanent magnetic vacuum breaker divide-shut brake provided by the invention and method to bring is:

1) avoid when using modified hysteresis control method thereof, increase integral coefficient and cause PWM regulating cycle to increase, the problem causing Current Control deviation to increase, makes controller output current near reference current, there will not be larger fluctuation, improves the output quality of electric current.

2) under Hysteresis control mode, output current and reference current are better coincide, usually require that system has higher sample rate, but due to control circuit output time delay, the time delay of transducer Gather and input, and the existence of the time delay such as control algolithm time delay, improve sampling and consider possibly fundamentally to solve the larger problem of current deviation.And apply this method and not only can reduce requirement to AD sample rate, alleviate the computation burden of processor in operation, the operational efficiency of raising system, and the output current of controller can be made more close to reference current curve, thus the raising making the quality of output current obtain to a great extent.When applying the method and realizing breaking-closing operating, can the reliability of effective guarantee breaking-closing operating.

Accompanying drawing explanation

Fig. 1 is that control current waveform in the present invention and reference waveform contrast block diagram.

Fig. 2 is the structured flowchart of the control device of permanent magnetic vacuum breaker divide-shut brake in the present invention.

Fig. 3 is that in the present invention, PWM control electric current and reference waveform contrast block diagram.

Fig. 4 is that the mixed type PWM in the present invention under oscilloscope controls current waveform figure.

Fig. 5 is that in the present invention, PWM control electric current and reference waveform contrast block diagram.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail:

As shown in Figures 1 to 5, according to the embodiment of the control device of a kind of permanent magnetic vacuum breaker divide-shut brake provided by the invention, comprise charge-discharge control unit, IGBT power stage unit, Phototube Coupling unit, analog signal conditioner unit and the key control unit with PWM controlling functions, storage capacitor real-time voltage and current feedback to energy storage capacitor discharge and recharge, and are given described key control unit according to the discharge and recharge signal from described key control unit by charge-discharge control unit;

Before breaking-closing operating, described key control unit, according to current capacitance voltage value, determines this PWM reference curve operated, thus determines the PWM duty cycle reference value that in divide-shut brake process, each moment is corresponding;

When carrying out breaking-closing operating, described Phototube Coupling unit carries out medium filtering and calculating current increment to the electric current gathered;

Key control unit, according to the duty cycle reference value of current time PWM, triggers IGBT by IGBT control unit and completes corresponding action, reach the object controlling electric current.Coil current can be made more close to reference current curve, reduce current ripples, improve electric current output quality.The method can make the controller of permanent magnetic vacuum breaker under the prerequisite not increasing control system burden, exports the electric current more close with reference current, realizes reliable and stable divide-shut brake.The method adopts mixed type PWM control technology, by fixed-frequency PWM control technology and Hysteresis control combine with technique, improves the quality of controller output current

Described control device adopts the control mode of coil current closed loop, and key control unit is by hysteresis control method thereof calculating current increment.

The current increment that described key control unit calculates according to hysteresis control method thereof, and export different dutyfactor values according to current increment, reach the object of Current adjustment.

Control device Real-Time Monitoring capacitance voltage, and before operation, calculate the reference value of PWM according to voltage, and in divide-shut brake control procedure, export different duty, carry out Current adjustment.

See Fig. 1 to Fig. 5, according to the control method of permanent magnetic vacuum breaker divide-shut brake provided by the invention, PWM with reference to formula in the computational methods of base value is, r=R _s+ n (R _e-R _s)/N,

In formula, n is in divide-shut brake process, and from the n-th sampling instant that moving contact motion starts, N is the sampling number completing the moment in divide-shut brake process from the moving contact initiating moment to divide-shut brake, and r is the reference PWM value of the n-th sampling instant, R _sfor the PWM duty ratio of divide-shut brake initial time, R _gfor the duty ratio of divide-shut brake end moment PWM, and:

$\left\{\begin{array}{c}{R}_s=1/\mathrm{\β}\\ R_e=\mathrm{\α}/\sqrt{{\mathrm{\β}}^2+({\mathrm{\α}}^2-1)/\mathrm{\γ}}\end{array}\right.$

When in formula, α is for obtaining reference curve, perform the divide-shut brake order end moment, the ratio of capacitance voltage and initial voltage, when β is normal divide-shut brake, the ratio of actual capacitance initial voltage and electric capacity initial voltage when obtaining reference curve, γ is the capacity chosen of actual divide-shut brake and the ratio of capacitance when obtaining reference curve.Before moving contact motion, the reference base value getting PWM is R _s.

See Fig. 1 to Fig. 5, according to the control method of permanent magnetic vacuum breaker divide-shut brake provided by the invention, based on the reference PWM duty ratio r of the n-th sampling instant, the upper limit PWM value R that the calculating corresponding moment should export ₁, and lower limit PWM value R ₂, R ₁and R ₂that chooses should follow two principles:

1) be R in duty ratio ₁time, guarantee that controller output current is greater than reference current;

2) be R in duty ratio ₂time, guarantee that controller output current is less than reference current.

See Fig. 1 to Fig. 5, according to the control method of permanent magnetic vacuum breaker divide-shut brake provided by the invention, for specific control system, after determining α value, under the capacitance that given γ value is corresponding, calculate the voltage reference value that the maximum reference variation amount of PWM is corresponding, wherein:

${\mathrm{\β}}_0=\sqrt{\frac{1-{\mathrm{\α}}^2}{\mathrm{\γ}(1-{\mathrm{\α}}^{2/3})}}$

β ₀be the voltage coefficient value that maximum PWM variable quantity is corresponding, can be choosing of practical operation voltage and reference is provided.

The value of Real-time Collection load current, and carry out data filtering according to formula (1), obtain the sampled current value i in the n-th moment _n:

$i_n=[\underset{k=n-3}{\overset{n}{\mathrm{\Σ}}}{x}_k-\mathrm{Max}(x_{n-3},x_{n-2},x_{n-1},x_n)-\mathrm{Min}(x_{n-3},x_{n-2},x_{n-1},x_n)]/2---\left(1\right)$

X in formula _kfor the current value that the kth moment is obtained by AD sampling, Max represent to get in bracket comprise the maximum of sampled value, Min represents and gets minimum value.

Through type (2) calculates s _nvalue

$\left\{\begin{array}{c}{y}_n=K_P(i_n-I_n)-K_D(i_n-i_{n-1})+K_I\underset{j=1}{\overset{n}{\mathrm{\&Sigma;}}}(i_j-I_j)\\ s_n=\left\{\begin{array}{cc}1& y_n>{\mathrm{\&Delta;I}}_M\\ 0& -{\mathrm{\&Delta;I}}_M\&le;y_n\&le;{\mathrm{\&Delta;I}}_M\\ -1& y_n<-{\mathrm{\&Delta;I}}_M\end{array}\right.\end{array}\right.---\left(2\right)$

I in formula _nbe the n-th moment reference current value, Δ I _mfor hysteresis band, K _p, K _d, K _ibe respectively ratio, differential and integral coefficient, work as s _nwhen value is 1, the duty ratio arranging PWM is R ₁, work as s _nfor-1 time, the duty ratio arranging PWM is R ₂, work as s _nwhen being 0, PWM duty ratio keeps current set point and does not make any change.

When closing a floodgate to 27.5kV bistable permanent-magnet vacuum circuit breaker, because the current waveform shown in controller output map 1 can make circuit breaker separate immediately after combined floodgate, namely cannot close a floodgate puts in place and keeps, and waveform sawtooth is obvious.When using mixed type PWM control methods instead, and to arrange PWM control cycle be 100 microseconds, R ₁be 100%, R ₂when being 86%, current output waveform as shown in Figure 3 can be obtained.As shown in Figure 3, switching current and reference current are very identical, also achieve reliable closing operation simultaneously, and its control effects is much better than the situation only using modified model Hysteresis control.Above-mentioned adjustment process does not increase the sample rate of AD, thus the more calculating avoiding raising sample rate and need carry out.

Because controller has carried out filtering to input signal in sampling process, the current waveform shown in Fig. 3, does not find out the adjustment process of PWM, and Fig. 4 gives the current waveform at oscilloscope down-sampling.Significantly can find out from Fig. 4 the vestige that PWM regulates, namely in Hysteresis control, be R when arranging PWM duty ratio ₂time, current waveform is with a small amount of burr.As can be seen from Figure 3, in the later stage of Hysteresis control, electric current is slightly higher, if in later stage control voltage still in higher level, so probably cause and get R in duty ratio ₂during value, electric current cannot decline, and Hysteresis control cannot normally be carried out.Therefore, in control method, the setting of PWM duty ratio realizes the very crucial factor of control program.For enabling control method obtain good control effects, must to R ₁and R ₂value analyze.

For obtaining R ₁and R ₂value, roughly can determine the curve that the value of PWM duty ratio in a divide-shut brake process linearly changes first on the whole, and with this curve as a reference, choose suitable R ₁and R ₂value.Because the object of current following in divide-shut brake process ensures that each divide-shut brake process travel path is consistent, therefore, can think that the energy approximation that each divide-shut brake consumes is equal, namely the energy of each electric capacity output is equal.When setting reference curve, reference voltage is U, and capacitance is C, and when completing feed motion, capacitance voltage drops to α U, then, when obtaining reference curve, the energy that electric capacity exports is:

W＝(1-α ²)CU ²/2， (3)

If actual switching voltage is β U, capacitance is γ C, so after combined floodgate completes, the voltage U of its electric capacity ' should be:

$U^{\&prime;}=\sqrt{({\mathrm{\&beta;}}^2\mathrm{\&gamma;}{\mathrm{CU}}^2/2-W)/(\mathrm{\&gamma;C}/2)}=U\sqrt{{\mathrm{\&beta;}}^2+({\mathrm{\&alpha;}}^2-1)/\mathrm{\&gamma;}},---\left(4\right)$

Because combined floodgate initial time capacitance voltage is β U, then according to the impulse equivalency principle of PWM, can set combined floodgate initial time PWM duty ratio is R _s=1/ β, requires β>=1 here, and namely practical operation voltage must on the voltage obtaining predetermined current curve.Meanwhile, General Requirements γ >=1, namely capacitance also must on the capacitance obtaining reference curve, and so initial time electric current should be able to be approximate consistent with reference current.In like manner in the combined floodgate end moment, the duty ratio of PWM should be:

$R_e=\mathrm{\&alpha;U}/U^{\&prime;}=\mathrm{\&alpha;}/\sqrt{{\mathrm{\&beta;}}^2+({\mathrm{\&alpha;}}^2-1)/\mathrm{\&gamma;}}---\left(5\right).$

In divide-shut brake process, because the whole operating process time is shorter, when moving contact does not start action, can think that voltage is substantially constant, now, PWM duty ratio can not regulate, after the initiating moment, can think approximate in the process that voltage moves at moving contact linearly to decline, thus the regulated value of PWM also can be thought approximate and linearly changes.It can thus be appreciated that, in divide-shut brake process, from the reference value of any time PWM after the moving contact initiating moment be:

r＝R _s+n(R _e-R _s)/N (6),

In formula, N is from the initiating moment to the sampling number having operated moment AD in divide-shut brake process, and n is n-th sampling, and its value is the integer from 0 to N.Because the initiating moment is generally little, therefore, above formula can be applied to whole making process, now, needs suitable increase R ₁value, and reduce R ₂value, thus make whole operating process electric current normally rise or to decline.

After the PWM reference value obtaining making process any time, R ₁with R ₂value can be added and subtracted on the basis of reference value.Due to R ₁value actual current increase ratio reference value must be made faster, therefore its value must be greater than reference value, in addition for avoiding the too fast of rising, electric current is caused to occur larger ripple, realize other compensation for leaving enough wish amounts simultaneously, and avoid occurring division calculation in adjustment process, simplify computational process, recommend R ₁reference value be (1+1/8) r, decline time, get R according to symmetry principle ₂value be (1-1/8) r.When practical application, other variable quantities can be chosen as required, as (1+1/16) r, (1+1/4) r etc.

After the PWM reference value obtaining making process any time, R ₁with R ₂value can be added and subtracted on the basis of reference value, and the variable quantity of PWM reference value is f (β), that is:

$f\left(\mathrm{\&beta;}\right)=R_e-R_s=\mathrm{\&alpha;}/\sqrt{{\mathrm{\&beta;}}^2+({\mathrm{\&alpha;}}^2-1)/\mathrm{\&gamma;}}-1/\mathrm{\&beta;}---\left(7\right).$

When practical application, capacitance is determined, namely γ is constant, but the operating voltage of divide-shut brake might not be stablized, and particularly in the situation of multiple shot reclosing, can obtain formula (7) differentiate:

f'(β)＝1/β ²-αβ/(β ²+(α ²-1)/γ) ^3/2(8)

From formula (8), f'(β) root be

$\mathrm{\&beta;}=\&PlusMinus;\sqrt{\frac{1-{\mathrm{\&alpha;}}^2}{\mathrm{\&gamma;}(1-{\mathrm{\&alpha;}}^{2/3})}}=\&PlusMinus;{\mathrm{\&beta;}}_0---\left(9\right)$

Can prove when meeting β ²during γ>=1, f (β)≤0 perseverance is set up, when reality uses, due to β>=1, and γ>=1, therefore β ²γ>=1 perseverance is set up.Because the value perseverance of β is greater than 1, therefore for formula (9) without the need to considering that root gets the situation of negative value.As β < β ₀time, f'(β) < 0, and as β > β ₀, f'(β) and > 0.It can thus be appreciated that f (β) is at β ₀place obtains minimum, again f (β)≤0 perseverance set up, that is now PWM reference value at β ₀point obtains unique minimum, and now the variable quantity of PWM value is maximum.In addition, from formula (9), β ₀value and the characteristic (namely load is larger, and electric capacity pressure drop is larger) of load and the actual capacitance used relevant.

Table 1 gives when γ=1, α value and β ₀and the relation between the maximum variable quantity of PWM.As shown in Table 1, when the capacitance obtaining reference curve is identical with the capacity of actual breaking-closing operating, the value of α is less, and the variable quantity of PWM reference value is larger.When γ=1 (under identical capacitance), the large I of load is directly reflected by α value, and α value is larger, then load is lighter, otherwise load is heavier.When α=1, namely electric capacity is close to time unloaded, and PWM reference value perseverance is constant, now need not carry out the correction of PWM reference value.

Table 1 α value and β ₀and the relation of the maximum variable quantity of PWM

Table 2 and table 3 sets forth when α=0.6 and α=0.9, the change of γ value and β ₀and the relation between the maximum variable quantity of PWM.From table 2 and table 3, increase with capacitance, the variable quantity of PWM reference value increases, and therefore, when capacitance increases, generally PWM value should not be approximately constant.Capacitive differential is larger, needed for the PWM correction value of carrying out also larger.

During table 2 α=0.6, γ value and β ₀and the relation of the maximum variable quantity of PWM

During table 3 α=0.9, γ value and β ₀and the relation of the maximum variable quantity of PWM

When obtaining good dynamic characteristic, usually require that capacitance is less, this can bring the impact of two aspects, during first acquisition reference curve, the pressure drop of electric capacity is general larger, namely α is less, it is two when being normal runnings, if the capacitance obtaining reference curve is less, then during practical application, capacitance must strengthen to tackle other special circumstances such as multiple shot reclosing, γ value is general larger in this case, from the data analysis of formula (9) and table 1 ~ table 3, both of these case all can make the variable quantity of PWM increase.That is the current reference curve obtained in this case, its PWM value generally can not be equivalent to constant value, must carry out linear revise, otherwise easily cause larger current fluctuation.

Be specifically described for the closing operation shown in Fig. 1.Voltage when obtaining reference curve shown in Fig. 1 is 220V, and the voltage of practical operation is 235V, and capacitance is identical with capacity when obtaining reference curve.It can thus be appreciated that β=1.068, γ=1, therefore can determine that the duty cycle reference value of initial time is R _s=93.6%, when obtaining reference curve, the end moment voltage that closes a floodgate approximately drops to 191V, and therefore α value is about 81.3%.

For this control system, when its PWM change measures maximum, the value of β is

${\mathrm{\&beta;}}_0=\sqrt{(1-{0.813}^2)/(1-{0.813}^{2/3})}=1.622$

Now

$f\left(\mathrm{\&beta;}\right)=0.813/\sqrt{{1.622}^2+{0.813}^2-1}-1/1.622=-0.0795$

It can thus be appreciated that for this system, the maximum variable quantity of reference value of its PWM is no more than 8%, changing value is also little, this is because the capacitance that reference curve obtains is the Capacitance parallel connection of 2 22000 μ F, capacitance is comparatively large, and the electric capacity obtaining reference curve is identical with the capacitance of normal running.

Value condition according to virtual voltage has:

$R_e=0.813/\sqrt{{1.086}^2+{0.813}^2-1}=0.908$

Sampling number during combined floodgate is 350 points, and therefore each PWM reference value change curve is:

r＝0.936+n(0.908-0.936)/N

From above formula, the change of each duty ratio is less, and therefore, desirable PWM reference value is constant 0.93, according to R ₁recommended range

R ₁＝1.125×0.93＝1.04

Because PWM duty ratio maximum is 100%, therefore desirable R ₁=100%, get R according to upper and lower symmetry principle ₂=86%, then can obtain waveform as shown in Figure 3.In figure 3, later stage electric current is slightly bigger than normal, this is because close a floodgate latter stage PWM reference value close to 90.8%, R ₂actual value is 86%, close to reference value, and R ₁be 100%, depart from reference value comparatively large, thus it is fast to make electric current increase, decline slow, current value ratio reference value is slightly higher.Now, suitably R can be reduced ₂value, to make actual current more close to reference current.When getting R ₂=84%, current curve as shown in Figure 5 can be obtained.

It is to be noted if make the reference value of PWM be constant, so must the r value that calculates of utility formula (6) at interval (R ₁, R ₂) within, and keep r value at (R as far as possible ₁+ R ₂)/about 2, thus ensure that electric current can rise reliably or decline.Comparison diagram 3 is known, at the controlling curve of later stage Fig. 5 more close to reference curve.Therefore there is better control effects.

As the above analysis, by mixed type PWM control to make controller output current and reference current more close, thus make on/off switch process more reliable.For ensureing that the stability of branch wire time provides reliable control method.

Claims (10)

1. a control method for permanent magnetic vacuum breaker divide-shut brake, is characterized in that: adopt mixed type PWM control technology, by fixed-frequency PWM control technology and Hysteresis control combine with technique, under the prerequisite not increasing system burden, improve the quality of controller output current, comprise the following steps

1) computation PWM is with reference to base value, under determining to correspond to specific divide-shut brake voltage, and the reference PWM base value that in divide-shut brake process, each moment is corresponding;

2) 4 medium filterings are utilized to calculate the real-time current value in each moment in divide-shut brake process;

3) utilize hysteresis control method thereof to calculate real-time current increment, and be according to setting the actual PWM duty ratio exported as R with increment ₁and R ₂.

2. the control method of permanent magnetic vacuum breaker divide-shut brake as claimed in claim 1, is characterized in that, and: PWM with reference to formula in the computational methods of base value is, r=R _s+ n (R _e-R _s)/N,

In formula, n is in divide-shut brake process, and from the n-th sampling instant that moving contact motion starts, N is the sampling number completing the moment in divide-shut brake process from the moving contact initiating moment to divide-shut brake, and r is the reference PWM value of the n-th sampling instant, R _sfor the PWM duty ratio of divide-shut brake initial time, R _gfor the duty ratio of divide-shut brake end moment PWM, and:

$\left\{\begin{array}{c}{R}_s=1/\mathrm{\&beta;}\\ R_e=\mathrm{\&alpha;}/\sqrt{{\mathrm{\&beta;}}^2+({\mathrm{\&alpha;}}^2-1)/\mathrm{\&gamma;}}\end{array}\right.$

When in formula, α is for obtaining reference curve, perform the divide-shut brake order end moment, the ratio of capacitance voltage and initial voltage, when β is normal divide-shut brake, the ratio of actual capacitance initial voltage and electric capacity initial voltage when obtaining reference curve, γ is the capacity chosen of actual divide-shut brake and the ratio of capacitance when obtaining reference curve.

3. the control method of permanent magnetic vacuum breaker divide-shut brake as claimed in claim 1, is characterized in that: based on the reference PWM duty ratio r of the n-th sampling instant, the upper limit PWM value R that the calculating corresponding moment should export ₁, and lower limit PWM value R ₂, R ₁and R ₂that chooses should follow two principles:

1) be R in duty ratio ₁time, guarantee that controller output current is greater than reference current;

2) be R in duty ratio ₂time, guarantee that controller output current is less than reference current.

4. the control method of permanent magnetic vacuum breaker divide-shut brake as claimed in claim 2, it is characterized in that: when PWM change in duty cycle amount is less, PWM reference value gets constant R to simplify the processing method of control procedure, wherein: PWM reference value constant gets R=(Re+Rs)/2.

5. the control method of permanent magnetic vacuum breaker divide-shut brake as claimed in claim 2, is characterized in that: after determining α value, under the capacitance that given γ value is corresponding, calculates the voltage reference value that the maximum reference variation amount of PWM is corresponding, wherein:

${\mathrm{\&beta;}}_0=\sqrt{\frac{1-{\mathrm{\&alpha;}}^2}{\mathrm{\&gamma;}(1-{\mathrm{\&alpha;}}^{2/3})}}$

β ₀be the voltage coefficient value that maximum PWM variable quantity is corresponding.

6. a control device for permanent magnetic vacuum breaker divide-shut brake, comprises charge-discharge control unit, IGBT power stage unit, Phototube Coupling unit, analog signal conditioner unit and key control unit, it is characterized in that:

Storage capacitor real-time voltage and current feedback to energy storage capacitor discharge and recharge, and are given described key control unit according to the discharge and recharge signal from described key control unit by charge-discharge control unit;

Before breaking-closing operating, described key control unit, according to current capacitance voltage value, determines this PWM reference curve operated, thus determines the PWM duty cycle reference value that in divide-shut brake process, each moment is corresponding;

When carrying out breaking-closing operating, described Phototube Coupling unit carries out medium filtering and calculating current increment to the electric current gathered;

Key control unit, according to the duty cycle reference value of current time PWM, triggers IGBT by IGBT control unit and completes corresponding action, reach the object controlling electric current.

7. the control device of permanent magnetic vacuum breaker divide-shut brake as claimed in claim 6, it is characterized in that: described control device adopts the control mode of coil current closed loop, key control unit is by hysteresis control method thereof calculating current increment.

8. the control device of permanent magnetic vacuum breaker divide-shut brake as claimed in claim 6, is characterized in that: described key control unit should have PWM controlling functions.

9. the control device of permanent magnetic vacuum breaker divide-shut brake as claimed in claim 6, it is characterized in that: the current increment that described key control unit calculates according to hysteresis control method thereof, and export different dutyfactor values according to current increment, reach the object of Current adjustment.

10. the control device of permanent magnetic vacuum breaker divide-shut brake as claimed in claim 6, is characterized in that: control device Real-Time Monitoring capacitance voltage, and before operation, the reference value of PWM is calculated according to voltage, and in divide-shut brake control procedure, export different duty, carry out Current adjustment.