CN104791757A - Coal-fired chain-grate boiler control system and control method thereof - Google Patents

Abstract

The invention discloses a coal-fired chain-grate boiler control system and a control method thereof. The coal-fired chain-grate boiler control system comprises a pressure detection module and a lower computer, wherein the pressure detection module is used for detecting an actual steam drum pressure measurement value PV (0) at the initial moment and an actual steam drum pressure measurement value PV (k) at the kth moment, and the lower computer is connected with a grate frequency converter and the pressure detection module, receives a given steam drum pressure value SV (0) at the initial moment and outputs a frequency control parameter u (k) at the kth moment to the grate frequency converter. The coal-fired chain-grate boiler control system can progressively track an actual steam drum value according to the guidance trajectory requirement, and response time is not prolonged while good control effect is obtained.

Description

Combustion coal chain boiler control system and control method thereof

Technical field

The present invention relates to combustion of industrial boiler control technology field, be specially a kind of combustion coal chain boiler control system and control method thereof.

Background technology

At present, combustion coal chain boiler remains leading position in boiler industry, accounts for more than 2/3 of all boiler total amounts.Domestic industry boiler design and manufacturing technology obtained very large development and raising in recent years, especially on the Design and manufacture of pressure-containing parts, large development is had, but, also there are some problems in combustion technology, complete auxiliaries and integral level, these problems make boiler operatiopn pressure often lower, generally be only about 50% of boiler rated operating pressure, boiler is often in underrun, and actual operating efficiency is generally low than boiler rated efficiency by more than 5% ~ 10%.Existing boiler is that the too small or load of capacity does not mate in the operating subject matter of use, and boiler combustion technology level is lower, causes final efficiency of combustion not high.

The task that industry boiler control system will complete mainly contains: 1. main steam flow will adapt to the change of load; 2. drum pressure remains in certain scope; 3. burner hearth keeps certain negative pressure; 4. steam water-level remains in certain scope.For boiler combustion process, mainly complete two tasks: 1. constant by regulating the hearth vacuum control loop of air inducing rotating speed to maintain combustion chamber draft; 2. constant by regulating the drum pressure control loop of fire grate rotating speed, coal supply rotating speed and air blast rotating speed to control drum pressure.

The Industrial Boiler of current Industrial Boiler, especially below 35t/h, its control program all adopts manual control mode or pid control mode usually, but for the violent combustion process of working conditions change, this kind of control program cannot realize good control.Although pid control mode obtains certain application on combustion of industrial boiler controls, it is difficult to take into account static characteristic and dynamic indicator, often because overshoot is excessive, saturation integral, fail good real-time matching controlled system characteristic and cause running collapse.Because drum pressure adjustment process has the difficult points such as time variation, hysteresis quality, Multivariable Coupling, so what have the drum pressure of many combustion coal chain boilers still to adopt at present is manual control mode.

For combustion coal chain boiler, the main controlled parameter realizing Combustion System comprises drum pressure, wind coal proportion and combustion chamber draft etc.Combustion coal chain boiler combustion process is a multiple-input and multiple-output complex process with Great inertia, long time delay, variable element, and pid control mode cannot provide high-quality control for the boiler combustion process with Great inertia, long time-delay and variable element.Particularly, pid control mode is main in combustion coal chain boiler Combustion System exists two class problems: when being 1. Spline smoothing for the Setting signal of drum pressure, due to the setting value of initial time drum pressure and measured value deviation excessive, often cause the overshoot that drum pressure is larger, occur the confusion controlled, this will cause potential safety hazard to boiler; 2. differential term is not made good use of, differential signal understands the control procedure of EVAC in control procedure to the amplification of noise, but because differential again can good predicated error to the controls in advance of error, reduce overshoot etc., so Appropriate application differential term also attracts the concern of numerous researcher all the time.

Summary of the invention

The present invention is directed to the proposition of above problem, and develop a kind of combustion coal chain boiler control system and control method thereof.

Technological means of the present invention is as follows:

A kind of combustion coal chain boiler control system, described combustion coal chain boiler comprises fire grate, blower motor, blower motor, coal supply motor and to hydroelectric machine; Described control system comprises:

The fire grate frequency converter be connected with described fire grate;

For the pressure detecting module of the actual drum pressure measured value PV (0) and actual drum pressure measured value PV (k) in kth moment of detecting initial time, wherein k order of representation, value are 1,2 ..., n;

Be connected with pressure detecting module with described fire grate frequency converter, and receive the drum pressure set-point SV (0) of initial time, and frequency control parameters u (k) in output kth moment is to the slave computer of fire grate frequency converter; The course of work of described slave computer is as follows:

1. SV is made _p(k)=SV _p(k-1)=PV (0), PV _p(k)=PV _p(k-1)=PV (0), u (k)=u (k-1)=0, k correct to n from 1; Wherein: SV _pthe location components of k drum pressure set-point that () is the kth moment, PV _pthe location components of k drum pressure measured value that () is the kth moment, SV _p(k-1) be the location components of the drum pressure set-point in kth-1 moment, PV _p(k-1) be the location components of the drum pressure measured value in kth-1 moment, u (k) is the frequency control parameters in kth moment, the frequency control parameters that u (k-1) is kth-1 moment, and k order of representation, value are 1,2 ..., n;

2. the location components PV of the drum pressure set-point SV (0) of initial time and the drum pressure measured value in kth moment is obtained _pdeviation e (k) between (k);

3. to the location components PV of the drum pressure set-point SV (0) of initial time with the drum pressure measured value in kth moment _pthe absolute value of deviation between (k) | e (k) |, limit DL1, dynamic deviation to limit DL2 to compare with steady-state deviation;

4. as | e (k) | > DL2 and e (k) > 0 time, the valve position controlling described fire grate frequency converter reaches the upper limit, namely sets frequency control parameters u (the k)=u (k) in kth moment _maxand export u (k) to described fire grate frequency converter, wherein u (k) _maxrepresent valve position higher limit, make k=k+1, return 2.;

5. as | e (k) | > DL2 and e (k) < 0 time, control described fire grate frequency converter valve position and reach lower limit, namely set frequency control parameters u (the k)=u (k) in kth moment _minand export u (k) to described fire grate frequency converter, wherein u (k) _minrepresent valve position lower limit, make k=k+1, return 2.;

6. as DL1 < | e (k) | < DL2, judges | SV _p(k)-PV (0) | whether be less than 0.95 × | SV (0)-PV (0) |, be perform 8., otherwise make SV _p(k)=SV _p(k-1)=PV (0), makes k=k+1, returns 2.;

7. as | e (k) | during < DL1, make SV _p(k)=SV _p(k-1) 9.=SV (0), perform;

8. according to formula $S{V}_P\left(k\right)=\frac{\mathrm{SV}\left(0\right)-\mathrm{PV}\left(0\right)}{T+1}+\frac{[S{V}_P(k-1)-\mathrm{PV}\left(0\right)]\&times;T}{T+1}+\mathrm{PV}\left(0\right)$ Draw the location components SV of the drum pressure set-point in kth moment _p(k), wherein T is time term regulating parameter, performs 9.;

9. according to formula S V _v(k)=SV _p' (k) draws the velocity component SV of the drum pressure set-point in kth moment _v(k), and according to formula PV _v(k)=PV _p' (k) draws the velocity component PV of the drum pressure measured value in kth moment _v(k), wherein, SV _pthe location components SV of the drum pressure set-point that ' (k) is the kth moment _pthe first derivative of (k), PV _pthe location components PV of the drum pressure measured value that ' (k) is the kth moment _pk 10. the first derivative of (), perform;

10. by formula Δ u (k)=A _p[SV _p(k)-PV _p(k)]+A _v[SV _v(k)-PV _v(k)] draw the variation delta u (k) of frequency control parameters u (k) in kth moment, wherein, A _pfor location entries regulating parameter, A _vfor speed term regulating parameter, perform ;

formula u (k)=u (k-1)+Δ u (k) is utilized to draw frequency control parameters u (k) in kth moment, and output frequency controling parameters u (k) to fire grate frequency converter to control the output frequency of described fire grate frequency converter, and then regulate the rotating speed of fire grate to realize the control of boiler-steam dome pressure, wherein, the frequency control parameters that u (k-1) is kth-1 moment, make k=k+1, return 2.;

In addition, described control system also comprises the flow sensor of the temperature sensor for detecting fire box temperature, the liquid level sensor detecting steam water-level and detection main steam flow; Described slave computer also for receiving steam water-level setting value, and adopts pid control mode to realize steam water-level closed-loop control according to the deviation of steam water-level setting value and actual steam water-level value;

In addition, described control system also comprises:

The air inducing frequency converter be connected with blower motor, the air blast frequency converter be connected with blower motor, the coal supply frequency converter be connected with coal supply motor, the feedwater frequency converter be connected with to hydroelectric machine;

Further, described slave computer receives the signal of pressure detecting module, temperature sensor, liquid level sensor and flow sensor output via field control cabinet, and realizes the control of fire grate frequency converter, air inducing frequency converter, air blast frequency converter, coal supply frequency converter and feedwater frequency converter.

A kind of combustion coal chain boiler control method, described combustion coal chain boiler comprises fire grate; Described fire grate is connected with fire grate frequency converter; Described control method comprises the steps:

S1: the actual drum pressure measured value PV (0) detecting initial time, and provide the drum pressure set-point SV (0) of initial time, perform S2;

S2: make SV _p(k)=SV _p(k-1)=PV (0), PV _p(k)=PV _p(k-1)=PV (0), u (k)=u (k-1)=0, k correct to n from 1; Wherein: SV _pthe location components of k drum pressure set-point that () is the kth moment, PV _pthe location components of k drum pressure measured value that () is the kth moment, SV _p(k-1) be the location components of the drum pressure set-point in kth-1 moment, PV _p(k-1) be the location components of the drum pressure measured value in kth-1 moment, u (k) is the frequency control parameters in kth moment, the frequency control parameters that u (k-1) is kth-1 moment, k order of representation, value are 1,2 ..., n, performs S3;

S3: actual drum pressure measured value PV (k) detecting the kth moment, and make the location components PV of the drum pressure measured value in kth moment _pk () is constantly equal to actual drum pressure measured value PV (k) in kth moment, perform S4;

S4: the location components PV obtaining the drum pressure set-point SV (0) of initial time and the drum pressure measured value in kth moment _pk the deviation e (k) between (), performs S5;

S5: to the location components PV of the drum pressure set-point SV (0) of initial time with the drum pressure measured value in kth moment _pthe absolute value of deviation between (k) | e (k) |, DL1, dynamic deviation is limit to limit DL2 to compare with steady-state deviation, when | e (k) | during > DL2, perform S6, as DL1 < | e (k) | < DL2, perform S7, when | e (k) | during < DL1, perform S12;

S6: as e (k) > 0, the valve position controlling described fire grate frequency converter reaches the upper limit, namely sets frequency control parameters u (the k)=u (k) in kth moment _maxand export u (k) to described fire grate frequency converter, as e (k) < 0, control described fire grate frequency converter valve position and reach lower limit, namely set frequency control parameters u (the k)=u (k) in kth moment _minand export u (k) to described fire grate frequency converter, and wherein, u (k) _maxrepresent valve position higher limit, u (k) _minrepresent valve position lower limit, make k=k+1, return S4;

S7: judge | SV _p(k)-PV (0) | whether be less than 0.95 × | SV (0)-PV (0) |, be perform S8, otherwise make SV _p(k)=SV _p(k-1)=PV (0), makes k=k+1, returns S4;

S8: according to formula $S{V}_P\left(k\right)=\frac{\mathrm{SV}\left(0\right)-\mathrm{PV}\left(0\right)}{T+1}+\frac{[S{V}_P(k-1)-\mathrm{PV}\left(0\right)]\&times;T}{T+1}+\mathrm{PV}\left(0\right)$ Draw the location components SV of the drum pressure set-point in kth moment _p(k), wherein T is time term regulating parameter, performs S9;

S9: according to formula S V _v(k)=SV _p' (k) draws the velocity component SV of the drum pressure set-point in kth moment _v(k), and according to formula PV _v(k)=PV _p' (k) draws the velocity component PV of the drum pressure measured value in kth moment _v(k), wherein, SV _pthe location components SV of the drum pressure set-point that ' (k) is the kth moment _pthe first derivative of (k), PV _pthe location components PV of the drum pressure measured value that ' (k) is the kth moment _pk the first derivative of (), performs S10;

S10: by formula Δ u (k)=A _p[SV _p(k)-PV _p(k)]+A _v[SV _v(k)-PV _v(k)] draw the variation delta u (k) of frequency control parameters u (k) in kth moment, wherein, A _pfor location entries regulating parameter, A _vfor speed term regulating parameter, perform S11;

S11: utilize formula u (k)=u (k-1)+Δ u (k) to draw frequency control parameters u (k) in kth moment, and output frequency controling parameters u (k) to fire grate frequency converter to control the output frequency of described fire grate frequency converter, and then regulate the rotating speed of fire grate to realize the control of boiler-steam dome pressure, wherein, the frequency control parameters that u (k-1) is kth-1 moment, make k=k+1, return S4;

S12: make SV _p(k)=SV _p(k-1)=SV (0), returns S9.

Owing to have employed technique scheme, combustion coal chain boiler control system provided by the invention and control method thereof, actual drum pressure value can be made according to one order inertia to lead the requirement of track, incremental tracking, response time can not be extended while the good control effects of acquisition, effectively can control uncertain large dead time non-linear object simultaneously, to the Combustion System of combustion coal chain boiler, there is good regulation quality, effectively can suppress the overshoot of drum pressure, vapour requirement is used when meeting, during main steam flow change, combustion coal chain boiler still stably can run under automatic control state.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is the structured flowchart of combustion coal chain boiler control system of the present invention;

Fig. 2, Fig. 3 are the flow charts of combustion coal chain boiler control method of the present invention;

Fig. 4 is the structural representation of existing combustion coal chain boiler;

Fig. 5 is the schematic diagram in the air output control loop of combustion coal chain boiler, air blast control loop, coal supply control loop and stocker control loop;

Fig. 6 is the schematic diagram of the feedwater control loop of combustion coal chain boiler;

Fig. 7 is the principle schematic that one order inertia leads control strategy;

Fig. 8 is the step response conditional curve figure of first order inertial loop;

Fig. 9 is the simulation curve figure that one order inertia leads control strategy;

Figure 10 is the operation curve schematic diagram adopting the present invention to realize combustion coal chain boiler control.

In figure: 1, water, 2, drum, 3, burner hearth, 4, coal bunker, 5, coal supply motor, 6, fire grate, 7, fire grate, 8, flue gas, 9, deduster, 10, blower motor, 11, air, 12, blower motor, 13, air preheater, 14, economizer, 15, chimney, 16, steam, 17, steam main, 18, feed main, 19, to hydroelectric machine.

Detailed description of the invention

For making the object of the embodiment of the present invention, technical scheme and advantage clearly, below in conjunction with the accompanying drawing in the embodiment of the present invention, technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making other embodiments all obtained under creative work prerequisite, belong to the scope of protection of the invention.

A kind of combustion coal chain boiler control system as shown in Figure 1, described combustion coal chain boiler comprise fire grate, blower motor, blower motor, coal supply motor and give hydroelectric machine; Described control system comprises: the fire grate frequency converter be connected with described fire grate; For the pressure detecting module of the actual drum pressure measured value PV (0) and actual drum pressure measured value PV (k) in kth moment of detecting initial time, wherein k order of representation, value are 1,2 ..., n; Be connected with pressure detecting module with described fire grate frequency converter, and receive the drum pressure set-point SV (0) of initial time, and frequency control parameters u (k) in output kth moment is to the slave computer of fire grate frequency converter; The course of work of described slave computer is as follows:

1. SV is made _p(k)=SV _p(k-1)=PV (0), PV _p(k)=PV _p(k-1)=PV (0), u (k)=u (k-1)=0, k correct to n from 1; Wherein: SV _pthe location components of k drum pressure set-point that () is the kth moment, PV _pthe location components of k drum pressure measured value that () is the kth moment, SV _p(k-1) be the location components of the drum pressure set-point in kth-1 moment, PV _p(k-1) be the location components of the drum pressure measured value in kth-1 moment, u (k) is the frequency control parameters in kth moment, the frequency control parameters that u (k-1) is kth-1 moment, and k order of representation, value are 1,2 ..., n;

2. the location components PV of the drum pressure set-point SV (0) of initial time and the drum pressure measured value in kth moment is obtained _pdeviation e (k) between (k);

3. to the location components PV of the drum pressure set-point SV (0) of initial time with the drum pressure measured value in kth moment _pthe absolute value of deviation between (k) | e (k) |, limit DL1, dynamic deviation to limit DL2 to compare with steady-state deviation;

4. as | e (k) | > DL2 and e (k) > 0 time, the valve position controlling described fire grate frequency converter reaches the upper limit, namely sets frequency control parameters u (the k)=u (k) in kth moment _maxand export u (k) to described fire grate frequency converter, wherein u (k) _maxrepresent valve position higher limit, make k=k+1, return 2.;

5. as | e (k) | > DL2 and e (k) < 0 time, control described fire grate frequency converter valve position and reach lower limit, namely set frequency control parameters u (the k)=u (k) in kth moment _minand export u (k) to described fire grate frequency converter, wherein u (k) _minrepresent valve position lower limit, make k=k+1, return 2.;

6. as DL1 < | e (k) | < DL2, judges | SV _p(k)-PV (0) | whether be less than 0.95 × | SV (0)-PV (0) |, be perform 8., otherwise make SV _p(k)=SV _p(k-1)=PV (0), makes k=k+1, returns 2.;

7. as | e (k) | during < DL1, make SV _p(k)=SV _p(k-1) 9.=SV (0), perform;

8. according to formula $S{V}_P\left(k\right)=\frac{\mathrm{SV}\left(0\right)-\mathrm{PV}\left(0\right)}{T+1}+\frac{[S{V}_P(k-1)-\mathrm{PV}\left(0\right)]\&times;T}{T+1}+\mathrm{PV}\left(0\right)$ Draw the location components SV of the drum pressure set-point in kth moment _p(k), wherein T is time term regulating parameter, performs 9.;

9. according to formula S V _v(k)=SV _p' (k) draws the velocity component SV of the drum pressure set-point in kth moment _v(k), and according to formula PV _v(k)=PV _p' (k) draws the velocity component PV of the drum pressure measured value in kth moment _v(k), wherein, SV _pthe location components SV of the drum pressure set-point that ' (k) is the kth moment _pthe first derivative of (k), PV _pthe location components PV of the drum pressure measured value that ' (k) is the kth moment _pk 10. the first derivative of (), perform;

10. by formula Δ u (k)=A _p[SV _p(k)-PV _p(k)]+A _v[SV _v(k)-PV _v(k)] draw the variation delta u (k) of frequency control parameters u (k) in kth moment, wherein, A _pfor location entries regulating parameter, A _vfor speed term regulating parameter, perform ;

formula u (k)=u (k-1)+Δ u (k) is utilized to draw frequency control parameters u (k) in kth moment, and output frequency controling parameters u (k) to fire grate frequency converter to control the output frequency of described fire grate frequency converter, and then regulate the rotating speed of fire grate to realize the control of boiler-steam dome pressure, wherein, the frequency control parameters that u (k-1) is kth-1 moment, make k=k+1, return 2.;

In addition, described control system also comprises the flow sensor of the temperature sensor for detecting fire box temperature, the liquid level sensor detecting steam water-level and detection main steam flow; Described slave computer also for receiving steam water-level setting value, and adopts pid control mode to realize steam water-level closed-loop control according to the deviation of steam water-level setting value and actual steam water-level value; In addition, described control system also comprises: the air inducing frequency converter be connected with blower motor, the air blast frequency converter be connected with blower motor, the coal supply frequency converter be connected with coal supply motor, the feedwater frequency converter be connected with to hydroelectric machine; Further, described slave computer receives the signal of pressure detecting module, temperature sensor, liquid level sensor and flow sensor output via field control cabinet, and realizes the control of fire grate frequency converter, air inducing frequency converter, air blast frequency converter, coal supply frequency converter and feedwater frequency converter.Described control system also comprises the host computer be connected with host computer; The drum pressure set-point SV (0) of described initial time is inputted by host computer by operator, and is passed to slave computer, and described host computer can adopt industrial computer, and described slave computer can adopt PLC.

A kind of combustion coal chain boiler control method as shown in Figures 2 and 3, described combustion coal chain boiler comprises fire grate; Described fire grate is connected with fire grate frequency converter; Described control method comprises the steps:

S1: the actual drum pressure measured value PV (0) detecting initial time, and provide the drum pressure set-point SV (0) of initial time, perform S2;

S2: make SV _p(k)=SV _p(k-1)=PV (0), PV _p(k)=PV _p(k-1)=PV (0), u (k)=u (k-1)=0, k correct to n from 1; Wherein: SV _pthe location components of k drum pressure set-point that () is the kth moment, PV _pthe location components of k drum pressure measured value that () is the kth moment, SV _p(k-1) be the location components of the drum pressure set-point in kth-1 moment, PV _p(k-1) be the location components of the drum pressure measured value in kth-1 moment, u (k) is the frequency control parameters in kth moment, the frequency control parameters that u (k-1) is kth-1 moment, k order of representation, value are 1,2 ..., n, performs S3;

S3: actual drum pressure measured value PV (k) detecting the kth moment, and make the location components PV of the drum pressure measured value in kth moment _pk () is constantly equal to actual drum pressure measured value PV (k) in kth moment, perform S4;

S4: the location components PV obtaining the drum pressure set-point SV (0) of initial time and the drum pressure measured value in kth moment _pk the deviation e (k) between (), performs S5;

S5: to the location components PV of the drum pressure set-point SV (0) of initial time with the drum pressure measured value in kth moment _pthe absolute value of deviation between (k) | e (k) |, DL1, dynamic deviation is limit to limit DL2 to compare with steady-state deviation, when | e (k) | during > DL2, perform S6, as DL1 < | e (k) | < DL2, perform S7, when | e (k) | during < DL1, perform S12;

S6: as e (k) > 0, the valve position controlling described fire grate frequency converter reaches the upper limit, namely sets frequency control parameters u (the k)=u (k) in kth moment _maxand export u (k) to described fire grate frequency converter, as e (k) < 0, control described fire grate frequency converter valve position and reach lower limit, namely set frequency control parameters u (the k)=u (k) in kth moment _minand export u (k) to described fire grate frequency converter, and wherein, u (k) _maxrepresent valve position higher limit, u (k) _minrepresent valve position lower limit, make k=k+1, return S4;

S7: judge | SV _p(k)-PV (0) | whether be less than 0.95 × | SV (0)-PV (0) |, be perform S8, otherwise make SV _p(k)=SV _p(k-1)=PV (0), makes k=k+1, returns S4;

S8: according to formula $S{V}_P\left(k\right)=\frac{\mathrm{SV}\left(0\right)-\mathrm{PV}\left(0\right)}{T+1}+\frac{[S{V}_P(k-1)-\mathrm{PV}\left(0\right)]\&times;T}{T+1}+\mathrm{PV}\left(0\right)$ Draw the location components SV of the drum pressure set-point in kth moment _p(k), wherein T is time term regulating parameter, performs S9;

S9: according to formula S V _v(k)=SV _p' (k) draws the velocity component SV of the drum pressure set-point in kth moment _v(k), and according to formula PV _v(k)=PV _p' (k) draws the velocity component PV of the drum pressure measured value in kth moment _v(k), wherein, SV _pthe location components SV of the drum pressure set-point that ' (k) is the kth moment _pthe first derivative of (k), PV _pthe location components PV of the drum pressure measured value that ' (k) is the kth moment _pk the first derivative of (), performs S10;

S10: by formula Δ u (k)=A _p[SV _p(k)-PV _p(k)]+A _v[SV _v(k)-PV _v(k)] draw the variation delta u (k) of frequency control parameters u (k) in kth moment, wherein, A _pfor location entries regulating parameter, A _vfor speed term regulating parameter, perform S11;

S11: utilize formula u (k)=u (k-1)+Δ u (k) to draw frequency control parameters u (k) in kth moment, and output frequency controling parameters u (k) to fire grate frequency converter to control the output frequency of described fire grate frequency converter, and then regulate the rotating speed of fire grate to realize the control of boiler-steam dome pressure, wherein, the frequency control parameters that u (k-1) is kth-1 moment, make k=k+1, return S4;

S12: make SV _p(k)=SV _p(k-1)=SV (0), returns S9.

Fig. 4 shows the structural representation of existing combustion coal chain boiler, as shown in Figure 4, combustion coal chain boiler mainly comprise drum 2, burner hearth 3, coal bunker 4, fire grate 7, deduster 9, air preheater 13, economizer 14, chimney 15, feed main 18, steam main 17, blower motor 10, blower motor 12, coal supply motor 5, to hydroelectric machine 19 and fire grate 6; The operation principle of combustion coal chain boiler be a kind of utilize coal combustion after the heat energy that discharges pass to water 1 in container, make water 1 reach the heat power equipment of required temperature or certain pressure steam 16.Boiler carries out at " pot " and " stove " two parts simultaneously, and after water 1 enters boiler, in boiler circuit, the heat transmission feedwater 1 that boiler heating surface will absorb, makes water 1 be heated into the steam 16 of uniform temperature and pressure, by extraction application.Air 11 imports by blower motor 12, and in combustion apparatus part, coal combustion constantly releases heat, and the high-temperature flue gas 8 that burning produces, by the propagation of heat, transfer heat to boiler heating surface, and self-temperature reduces gradually, finally discharged by chimney 15.

Fig. 5 shows the air output control loop of combustion coal chain boiler, air blast control loop, coal supply control loop and stocker control loop, as shown in Figure 5, air output control circuit controls be the rotating speed of blower motor, PID is adopted to control, and then it is stable to make combustion chamber draft maintain near tiny structure, wherein the rotating speed of blower motor is the feedforward amount in air output control loop; What air blast control loop controlled is the rotating speed of blower motor, according to the ratio of coal supply motor speed and then the coal-air ratio controlling boiler combustion, also adopts PID to control; What coal supply control loop controlled is the rotating speed of coal supply motor, according to the ratio of fire-grating motor speed, controls the rotating speed of coal supply motor, and the same PID of employing controls; Namely the realization for air output control loop, air blast control loop and coal supply control loop still adopts existing pid control mode; For stocker control loop, its controlled device is drum pressure, because existing pid control mode is difficult to the rotating speed regulating fire grate along with the change of load, and then realize controlling stable requirement to drum pressure, and the main controlled volume that drum pressure controls as boiler combustion, therefore adopt control mode of the present invention effectively to control drum pressure, wherein main steam flow is the feedforward amount in stocker control loop.Fig. 6 shows the schematic diagram of the feedwater control loop of combustion coal chain boiler, what feedwater control loop controlled is to the rotating speed of hydroelectric machine, thus make steam water-level maintain in certain stability range, still adopt PID to control, wherein main steam flow and feedwater flow are two feedforward amounts of feedwater control loop.

Control method of the present invention also can be described as one order inertia and leads control method; Steady-state deviation limit DL1 of the present invention and dynamic deviation limit DL2 is the deviation limit value of setting, wherein: DL1 and DL2, according to technological requirement setting, is positive number, and DL1 < DL2.When | e (k) | > DL2, i.e. the location components PV of the drum pressure set-point SV (0) of initial time and the drum pressure measured value in kth moment _pk the absolute value of the deviation between () is greater than dynamically limits DL2, then illustrate that the deviation between the setting value of controlled device and actual value is larger, in order to the desired value making controlled volume arrive setting fast, employing is needed to carry out control strategy efficiently, be specially: as | e (k) | > DL2 and e (k) > 0 time, control described fire grate frequency converter valve position and reach the upper limit, namely set frequency control parameters u (the k)=u (k) in kth moment _maxand export u (k) to described fire grate frequency converter; As | e (k) | > DL2 and e (k) < 0 time, control described fire grate frequency converter valve position and reach lower limit, namely set frequency control parameters u (the k)=u (k) in kth moment _minand export u (k) to described fire grate frequency converter.As DL1 < | e (k) | the location components PV of the drum pressure set-point SV (0) of < DL2 and initial time and the drum pressure measured value in kth moment _pk the absolute value of the deviation between (), between steady-state deviation limit DL1 and dynamic deviation limit DL2, so in order to make controlled volume arrive setting value stably, being eliminated concussion and overshoot as much as possible, being adopted one order inertia to lead control strategy, being specially: when | SV _p(k)-PV (0) | be less than 0.95 × | SV (0)-PV (0) | time, according to formula $S{V}_P\left(k\right)=\frac{\mathrm{SV}\left(0\right)-\mathrm{PV}\left(0\right)}{T+1}+\frac{[S{V}_P(k-1)-\mathrm{PV}\left(0\right)]\&times;T}{T+1}+\mathrm{PV}\left(0\right)$ Draw the location components SV of the drum pressure set-point in kth moment _pk (), wherein T is time term regulating parameter, then according to formula S V _v(k)=SV _p' (k) draws the velocity component SV of the drum pressure set-point in kth moment _v(k), and according to formula PV _v(k)=PV _p' (k) draws the velocity component PV of the drum pressure measured value in kth moment _v(k), then by formula Δ u (k)=A _p[SV _p(k)-PV _p(k)]+A _v[SV _v(k)-PV _v(k)] draw the variation delta u (k) of frequency control parameters u (k) in kth moment, formula u (k)=u (k-1)+Δ u (k) is finally utilized to draw frequency control parameters u (k) in kth moment, and output frequency controling parameters u (k) to fire grate frequency converter to control the output frequency of described fire grate frequency converter, and then regulate the rotating speed of fire grate to realize the control of boiler-steam dome pressure

Fig. 7 shows the principle schematic that one order inertia leads control strategy, and for the present invention, the controlled device in Fig. 7 is drum pressure, and particularly, one order inertia leads the increment type equation of control strategy to be:

Δu(k)＝A _P[SV _P(k)-PV _P(k)]+A _V[SV _V(k)-PV _V(k)]

Δu(k)＝A _P[SV _P(k)-PV _P(k)]+A _V[SV _P′(k)-PV _P′(k)]

Δu(k)＝A _P[SV _P(k)-PV _P(k)]+A _V[SV _P(k)-PV _P(k)]′

Δu(k)＝A _Pe ^*(k)+A _VΔe ^*(k)

Δu(k)＝A _Pe ^*(k)+A _V[e ^*(k)-e ^*(k-1)]

Wherein, Δ u (k) be frequency control parameters u (k) variable quantity, A _pfor location entries regulating parameter, SV _plocation components, the PV of k drum pressure set-point that () is the kth moment _plocation components, the A of k drum pressure measured value that () is the kth moment _vfor speed term regulating parameter, SV _vvelocity component, the PV of k drum pressure set-point that () is the kth moment _vvelocity component, the SV of k drum pressure measured value that () is the kth moment _pthe location components SV of the drum pressure set-point that ' (k) is the kth moment _pthe first derivative of (k), PV _pthe location components PV of the drum pressure measured value that ' (k) is the kth moment _pthe first derivative of (k), wherein: e ^*k () is the location components SV of drum pressure set-point _pthe location components PV of (k) and drum pressure measured value _pk the deviation between () is e ^*(k)=SV _p(k)-PV _p(k); Δ e ^*k () is e ^*k the differential of (), i.e. first derivative are Δ e ^*(k)=e ^*(k)-e ^*(k-1)=SV _v(k)-PV _v(k).Time term regulating parameter T of the present invention, location entries regulating parameter A _pwith speed term regulating parameter A _vall artificially preset, can be found out by increment type equation, the differential of location components is exactly velocity component, allow the velocity component of velocity component tracing preset value of measured value, " differential " using both differences as error, just can eliminate the amplification of differential to noise, and then can have controls in advance effect to error, can also good predicated error, reduce overshoot etc.; Therefore the process control simultaneously to course location and two the aspect combinations of process speed is converted to the control of simple target position to, the control better realized position by the control to advanced speed.And A _plocation entries weight coefficient, in conjunction with the location components SV of the drum pressure set-point in kth moment _pthe location components PV of the drum pressure measured value in (k) and kth moment _pdeviation e between (k) ^*(k), then the control action of position will be had an effect; And A _vspeed term weight coefficient, in conjunction with the velocity component SV of the drum pressure set-point in kth moment _vthe velocity component PV of the drum pressure measured value in (k) and kth moment _vdeviation delta e between (k) ^*k (), then the control action of speed will be had an effect, and reaches control object by combination control position and control rate two kinds of means.

Fig. 8 shows the step response conditional curve figure of first order inertial loop, and Fig. 9 shows the simulation curve figure that one order inertia leads control strategy; As shown in Figure 8, Figure 9, original Step reference value is after first order inertial loop leads, convert the location components (i.e. the step response transient process of first order inertial loop) of Step reference value to, the location components of Step reference value becomes the velocity component of Step reference value after differential process (first derivative process); The location components of actual measured value that is measured value, the location components of measured value becomes the velocity component of measured value after differential process (first derivative process).Utilize the velocity component of measured value to follow the velocity component of (step) set-point, namely follow one order inertia and lead track, carry out controls in advance to system, co-located item controls to coordinate to reach better control effects together.In boiler implosion application of the present invention, topmost controlled device is drum pressure, by coordinating time term regulating parameter T, location entries regulating parameter A _pwith speed term regulating parameter A _vdrum pressure can be made to obtain good control effects.When | e (k) | during < DL1, namely actual drum pressure measured value has entered in steady-state deviation limit DL1, represents that controlled volume is very close to setting value, thinks that system reaches technique stable state.

Figure 10 shows the operation curve schematic diagram adopting the present invention to realize combustion coal chain boiler to control, and as shown in Figure 10, adopts the operation conditions of the 15t/h combustion coal chain boiler of control system of the present invention or control method in some day 24h.Wherein 0 ~ 4h and 20 ~ 24h is the blowing out stage, 5 ~ 19h is for burning heater stage, and be automatic burning state of a control, in the 5 ~ 12h in the morning these 7 hours, drum pressure setting value is 0.33Mpa, in 12 ~ 19h in the afternoon these 7 hours, drum pressure setting value is 0.44Mpa, when main steam flow fluctuation is larger, owing to have employed control system of the present invention or control method, make drum pressure stable maintenance near drum pressure setting value, and deviation is little; Given drum pressure setting value step signal during 12h at noon, drum pressure is also transitioned into 0.44Mpa more reposefully from 0.33Mpa.Corresponding, the control system being core in regulatory PID control mode or controlling party rule are difficult to control well drum pressure, still easily produce larger fluctuation with external load change.For this large time constant system of boiler combustion system, control system of the present invention or control method are better than with regulatory PID control mode be core control system or control method.

Combustion coal chain boiler control system provided by the invention and control method thereof, actual drum pressure value can be made according to one order inertia to lead the requirement of track, incremental tracking, response time can not be extended while the good control effects of acquisition, effectively can control uncertain large dead time non-linear object simultaneously, to the Combustion System of combustion coal chain boiler, there is good regulation quality, effectively can suppress the overshoot of drum pressure, vapour requirement is used when meeting, during main steam flow change, combustion coal chain boiler still stably can run under automatic control state.

The above; be only the present invention's preferably detailed description of the invention; but protection scope of the present invention is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses; be equal to according to technical scheme of the present invention and inventive concept thereof and replace or change, all should be encompassed within protection scope of the present invention.

Claims (5)

1. a combustion coal chain boiler control system, described combustion coal chain boiler comprise fire grate, blower motor, blower motor, coal supply motor and give hydroelectric machine; It is characterized in that, described control system comprises:

The fire grate frequency converter be connected with described fire grate;

For the pressure detecting module of the actual drum pressure measured value PV (0) and actual drum pressure measured value PV (k) in kth moment of detecting initial time, wherein k order of representation, value are 1,2 ..., n;

Be connected with pressure detecting module with described fire grate frequency converter, and receive the drum pressure set-point SV (0) of initial time, and frequency control parameters u (k) in output kth moment is to the slave computer of fire grate frequency converter; The course of work of described slave computer is as follows:

1. SV is made _p(k)=SV _p(k-1)=PV (0), PV _p(k)=PV _p(k-1)=PV (0), u (k)=u (k-1)=0, k correct to n from 1; Wherein: SV _pthe location components of k drum pressure set-point that () is the kth moment, PV _pthe location components of k drum pressure measured value that () is the kth moment, SV _p(k-1) be the location components of the drum pressure set-point in kth-1 moment, PV _p(k-1) be the location components of the drum pressure measured value in kth-1 moment, u (k) is the frequency control parameters in kth moment, the frequency control parameters that u (k-1) is kth-1 moment, and k order of representation, value are 1,2 ..., n;

2. the location components PV of the drum pressure set-point SV (0) of initial time and the drum pressure measured value in kth moment is obtained _pdeviation e (k) between (k);

3. to the location components PV of the drum pressure set-point SV (0) of initial time with the drum pressure measured value in kth moment _pthe absolute value of deviation between (k) | e (k) |, limit DL1, dynamic deviation to limit DL2 to compare with steady-state deviation;

4. as | e (k) | > DL2 and e (k) > 0 time, the valve position controlling described fire grate frequency converter reaches the upper limit, namely sets frequency control parameters u (the k)=u (k) in kth moment _maxand export u (k) to described fire grate frequency converter, wherein u (k) _maxrepresent valve position higher limit, make k=k+1, return 2.;

5. as | e (k) | > DL2 and e (k) < 0 time, control described fire grate frequency converter valve position and reach lower limit, namely set frequency control parameters u (the k)=u (k) in kth moment _minand export u (k) to described fire grate frequency converter, wherein u (k) _minrepresent valve position lower limit, make k=k+1, return 2.;

6. as DL1 < | e (k) | < DL2, judges | SV _p(k)-PV (0) | whether be less than 0.95 × | SV (0)-PV (0) |, be perform 8., otherwise make SV _p(k)=SV _p(k-1)=PV (0), makes k=k+1, returns 2.;

7. as | e (k) | during < DL1, make SV _p(k)=SV _p(k-1) 9.=SV (0), perform;

8. according to formula ${\mathrm{SV}}_P\left(k\right)=\frac{\mathrm{SV}\left(0\right)-\mathrm{PV}\left(0\right)}{T+1}+\frac{[{\mathrm{SV}}_P(k-1)-\mathrm{PV}\left(0\right)]\&times;T}{T+1}+\mathrm{PV}\left(0\right)$ Draw the location components SV of the drum pressure set-point in kth moment _p(k), wherein T is time term regulating parameter, performs 9.;

9. according to formula S V _v(k)=SV _p' (k) draws the velocity component SV of the drum pressure set-point in kth moment _v(k), and according to formula PV _v(k)=PV _p' (k) draws the velocity component PV of the drum pressure measured value in kth moment _v(k), wherein, SV _pthe location components SV of the drum pressure set-point that ' (k) is the kth moment _pthe first derivative of (k), PV _pthe location components PV of the drum pressure measured value that ' (k) is the kth moment _pk 10. the first derivative of (), perform;

10. by formula Δ u (k)=A _p[SV _p(k)-PV _p(k)]+A _v[SV _v(k)-PV _v(k)] draw the variation delta u (k) of frequency control parameters u (k) in kth moment, wherein, A _pfor location entries regulating parameter, A _vfor speed term regulating parameter, perform

formula u (k)=u (k-1)+Δ u (k) is utilized to draw frequency control parameters u (k) in kth moment, and output frequency controling parameters u (k) to fire grate frequency converter to control the output frequency of described fire grate frequency converter, and then regulate the rotating speed of fire grate to realize the control of boiler-steam dome pressure, wherein, the frequency control parameters that u (k-1) is kth-1 moment, make k=k+1, return 2..

2. combustion coal chain boiler control system according to claim 1, is characterized in that, described control system also comprises the flow sensor of the temperature sensor for detecting fire box temperature, the liquid level sensor detecting steam water-level and detection main steam flow; Described slave computer also for receiving steam water-level setting value, and adopts pid control mode to realize steam water-level closed-loop control according to the deviation of steam water-level setting value and actual steam water-level value.

3. combustion coal chain boiler control system according to claim 1, is characterized in that described control system also comprises:

The air inducing frequency converter be connected with blower motor, the air blast frequency converter be connected with blower motor, the coal supply frequency converter be connected with coal supply motor, the feedwater frequency converter be connected with to hydroelectric machine.

4. combustion coal chain boiler control system according to claim 3, it is characterized in that described slave computer receives the signal of pressure detecting module, temperature sensor, liquid level sensor and flow sensor output via field control cabinet, and realize the control of fire grate frequency converter, air inducing frequency converter, air blast frequency converter, coal supply frequency converter and feedwater frequency converter.

5. a combustion coal chain boiler control method, described combustion coal chain boiler comprises fire grate; Described fire grate is connected with fire grate frequency converter; It is characterized in that, described control method comprises the steps:

S1: the actual drum pressure measured value PV (0) detecting initial time, and provide the drum pressure set-point SV (0) of initial time, perform S2;

S2: make SV _p(k)=SV _p(k-1)=PV (0), PV _p(k)=PV _p(k-1)=PV (0), u (k)=u (k-1)=0, k correct to n from 1; Wherein: SV _pthe location components of k drum pressure set-point that () is the kth moment, PV _pthe location components of k drum pressure measured value that () is the kth moment, SV _p(k-1) be the location components of the drum pressure set-point in kth-1 moment, PV _p(k-1) be the location components of the drum pressure measured value in kth-1 moment, u (k) is the frequency control parameters in kth moment, the frequency control parameters that u (k-1) is kth-1 moment, k order of representation, value are 1,2 ..., n, performs S3;

S3: actual drum pressure measured value PV (k) detecting the kth moment, and make the location components PV of the drum pressure measured value in kth moment _pk () is constantly equal to actual drum pressure measured value PV (k) in kth moment, perform S4;

S4: the location components PV obtaining the drum pressure set-point SV (0) of initial time and the drum pressure measured value in kth moment _pk the deviation e (k) between (), performs S5;

S5: to the location components PV of the drum pressure set-point SV (0) of initial time with the drum pressure measured value in kth moment _pthe absolute value of deviation between (k) | e (k) |, DL1, dynamic deviation is limit to limit DL2 to compare with steady-state deviation, when | e (k) | during > DL2, perform S6, as DL1 < | e (k) | < DL2, perform S7, when | e (k) | during < DL1, perform S12;

S6: as e (k) > 0, the valve position controlling described fire grate frequency converter reaches the upper limit, namely sets frequency control parameters u (the k)=u (k) in kth moment _maxand export u (k) to described fire grate frequency converter, as e (k) < 0, control described fire grate frequency converter valve position and reach lower limit, namely set frequency control parameters u (the k)=u (k) in kth moment _minand export u (k) to described fire grate frequency converter, and wherein, u (k) _maxrepresent valve position higher limit, u (k) _minrepresent valve position lower limit, make k=k+1, return S4;

S7: judge | SV _p(k)-PV (0) | whether be less than 0.95 × | SV (0)-PV (0) |, be perform S8, otherwise make SV _p(k)=SV _p(k-1)=PV (0), makes k=k+1, returns S4;

S8: according to formula ${\mathrm{SV}}_P\left(k\right)=\frac{\mathrm{SV}\left(0\right)-\mathrm{PV}\left(0\right)}{T+1}+\frac{[{\mathrm{SV}}_P(k-1)-\mathrm{PV}\left(0\right)]\&times;T}{T+1}+\mathrm{PV}\left(0\right)$ Draw the location components SV of the drum pressure set-point in kth moment _p(k), wherein T is time term regulating parameter, performs S9;

S9: according to formula S V _v(k)=SV _p' (k) draws the velocity component SV of the drum pressure set-point in kth moment _v(k), and according to formula PV _v(k)=PV _p' (k) draws the velocity component PV of the drum pressure measured value in kth moment _v(k), wherein, SV _pthe location components SV of the drum pressure set-point that ' (k) is the kth moment _pthe first derivative of (k), PV _pthe location components PV of the drum pressure measured value that ' (k) is the kth moment _pk the first derivative of (), performs S10;

S10: by formula Δ u (k)=A _p[SV _p(k)-PV _p(k)]+A _v[SV _v(k)-PV _v(k)] draw the variation delta u (k) of frequency control parameters u (k) in kth moment, wherein, A _pfor location entries regulating parameter, A _vfor speed term regulating parameter, perform S11;

S11: utilize formula u (k)=u (k-1)+Δ u (k) to draw frequency control parameters u (k) in kth moment, and output frequency controling parameters u (k) to fire grate frequency converter to control the output frequency of described fire grate frequency converter, and then regulate the rotating speed of fire grate to realize the control of boiler-steam dome pressure, wherein, the frequency control parameters that u (k-1) is kth-1 moment, make k=k+1, return S4;

S12: make SV _p(k)=SV _p(k-1)=SV (0), returns S9.