CN107218594A - Boiler Steam Temperature many reference amounts intelligence control system - Google Patents

Abstract

The invention discloses a boiler main steam temperature multi-parameter intelligent control system, comprising a water supply system and a main steam system, the main steam system is provided with a boiler steam drum, and a first-stage superheater sequentially arranged on the boiler steam drum output steam gas path , primary desuperheater, panel superheater, secondary desuperheater, secondary superheater and steam header, through internal model controller, desuperheating control system, third interference module, internal model module and adaptive The PID correction modules interact and cooperate with each other to realize the control of the main steam temperature, stabilize the main steam temperature, and reduce the accumulated deviation of the main steam temperature. Beneficial effects: the temperature of the main steam is stable, the response to the interference signal is quick, the influence of the interference on the main steam is reduced, and the accumulated error of the main steam is small.

Description

Boiler Main Steam Temperature Multi-parameter Intelligent Control System

technical field

The invention relates to the technical field of temperature control of thermal power boiler main steam, in particular to a multi-parameter intelligent control system for main steam temperature of a boiler.

Background technique

As one of the three important equipment (boiler, steam turbine and generator) in the process of thermal power generation, the boiler is the most important production equipment, and it is the key to power the steam turbine during the operation of the power plant.

In the process of power generation, the temperature of the main steam (also called superheated steam) at the final outlet of the boiler superheater is an important control parameter of the boiler unit, and its control quality directly affects the safe and economical operation of the entire unit. Since the superheater of the power plant boiler is in operation, its temperature is close to the maximum temperature of the metal of the superheater. If the steam temperature is too high, the strength of the superheater pipe will be reduced, and the service life will be shortened. If it is operated at a temperature of 10-20°C for a long time, its service life will be shortened. Half, long-term overheating will cause the superheater to deform and burst, affecting its safety; if the steam temperature is too low, the thermal efficiency of the entire unit cycle will decrease. Usually, every 5-10°C decrease in steam temperature will reduce its efficiency by about 1%. . For steam turbines, too high main steam temperature will cause excessive thermal stress and damage to the high-pressure cylinder turbine; too low main steam temperature will increase the humidity of the steam passing through the last few blades of the steam turbine, resulting in blade wear. In addition, temperature fluctuations will cause metal fatigue in the metal pipes and components of boilers and steam turbines, and will also cause changes in the expansion difference between the turbine cylinder and rotor, and even cause severe vibrations, endangering the safe operation of the unit. Therefore, the final main steam temperature at the outlet of the superheater must be strictly controlled within the specified range. It is usually required not to exceed -10～+5℃ of the rated value, and the deviation fluctuation range of long-term operation shall not exceed ±5℃. The rated operating temperature of the main steam is usually above 500°C.

As can be seen from Figure 1, it includes a water supply system and a main steam system, and the main steam system includes boiler drums connected in sequence, a primary superheater, a primary desuperheater, a panel superheater, a secondary desuperheater, Secondary superheater and steam header. The two-stage desuperheater is located between the two-stage superheaters. Its purpose is to ensure that the steam temperature of each stage is within the normal range, to ensure that the steam pipeline is not damaged, and to make the final main steam temperature parameters reach the required value. The saturated steam from the steam drum first passes through the first-stage superheater, then passes through the two-stage desuperheater to reduce the temperature, and finally outputs the required main steam from the second-stage superheater. The independent control of the outlet steam temperature of each desuperheater is realized by adjusting the desuperheating water flow rate of the two-stage desuperheater, and the desuperheater water of the two-stage desuperheater comes from the jellyfish pipe. Since the boiler drum liquid level is controlled by adjusting the opening of the main feedwater valve, the boiler feedwater pump supplies water quantitatively under the state of power frequency. In this way, the water pressure fluctuation of the feedwater mother pipe can be guaranteed to be small, and the disturbance to the desuperheating water flow is also small. , the outlet steam temperature of the two-stage desuperheater can meet the control requirements, and the final main steam temperature deviation is not large, so as to indirectly realize the control of the main steam temperature. However, in this working mode, because the maximum steam generated by the boiler is about 220t/h, and the power of each boiler feed water pump is about 1000kW, when the main feed water regulating valve is not fully opened, a large pressure difference will be generated before and after the valve. Cause throttling loss is too large.

In response to the national requirements for energy saving and consumption reduction, many domestic boilers are gradually undergoing frequency conversion energy-saving transformation, that is, adding frequency converter devices to the feed water pump, and then fully opening the main feed water regulating valve. By detecting the drum liquid level, according to the liquid level deviation through The frequency converter automatically adjusts the frequency of the feed water pump to control the feed water volume to control the liquid level of the steam drum. However, this modified operation mode has brought new problems. During the adjustment process, the water pressure of the main pipe will fluctuate with the change of the boiler steam volume, and the flow interference of the desuperheating water valve will also increase accordingly, resulting in various desuperheating. The control accuracy of the steam temperature at the outlet of the device is deteriorated. Since the current control method does not directly incorporate the required main steam temperature into the control system, the accumulation of steam temperature deviations in each control section will eventually cause the outlet main steam temperature to deviate from the required temperature value.

In the actual process, each control section adopts simple conventional PID control. When the main steam temperature deviates from the required temperature value range, the final main steam temperature value is manually observed, and the outlet steam of each desuperheater is manually set in sections. The temperature control value is used to indirectly control the final main steam temperature. Therefore, the requirements for operators are very high. Not only do they need rich relevant professional knowledge, but they must also have a proficient level of control. If the control is not timely, it is difficult to quickly It is obvious that this control method is difficult to achieve precise control of the main steam temperature. By consulting a large number of relevant literature, the current domestic boiler main steam temperature basically adopts this control method, that is, the current control method cannot meet the requirements of precise automatic control.

Due to the large inertia and delay of the controlled object in the process of boiler main steam temperature control, as well as various interference effects such as steam flow, flue gas heat, and desuperheating water flow fluctuations, the combined effect of these factors further reduces the influence on the main steam temperature. controllability index. Based on the above-mentioned system and its defects, the structure of the system cannot be greatly changed, and the independent water supply to the boiler drum, primary desuperheater, and secondary desuperheater cannot be carried out, and the defects of the main steam temperature control of the boiler cannot be changed.

In order to ensure that the control of the main steam temperature is safe and stable, it is more and more important to automatically control it. Therefore, how to realize the stability of the main steam temperature in the steam production process and improve the quality of the main steam temperature control has important practical significance and practical value.

Contents of the invention

Aiming at the above problems, the present invention provides a multi-parameter intelligent control system for boiler main steam temperature, which has rapid control, stable main steam temperature, small temperature error and high reliability.

In order to achieve the above object, the concrete technical scheme that the present invention adopts is as follows:

A boiler main steam temperature multi-parameter intelligent control system, including a water supply system and a main steam system, the main steam system is provided with a boiler drum, and a first-stage superheater and a first-stage reducer are sequentially arranged on the output steam path of the boiler drum. superheater, panel superheater, secondary desuperheater, secondary superheater and steam header, a first temperature monitor is set at the steam outlet of the primary desuperheater, and a first temperature monitor is installed at the steam outlet of the secondary The steam outlet of the desuperheater is provided with a second temperature monitor, and the steam outlet of the secondary superheater is provided with a third temperature monitor. The water supply system includes a water tank, and the water in the water tank is pumped by the water feeder. The water in the water tank is transported to the first-stage desuperheater through the water feeder pump and the first-stage desuperheating water flow valve, and the water in the water tank is also sent to the first-stage desuperheater through the water feeder pump and the second-stage desuperheating water The flow valve is delivered to the secondary desuperheater, the key lies in:

The main steam system is also provided with a main steam control system, the main steam control system includes an internal model controller, a temperature reduction control module, a third interference module and an internal model module; the internal model controller obtains the first difference signal ΔT ₁ and output the main steam temperature control signal T ₁ ; the desuperheating control module performs the desuperheating process of the first-stage desuperheater and the second-stage desuperheater step by step according to the main steam temperature control signal T ₁ control, so as to change the secondary superheated steam temperature value t ₃ of the output steam of the secondary superheater; the third disturbance module collects the third disturbance driving signal D ₀ and outputs the third disturbance signal g, the third disturbance signal g The actual temperature signal T ₀ of the main steam is obtained after making a difference with the temperature value t ₃ of the secondary superheated steam; the internal model module obtains the temperature control signal T ₁ of the main steam and outputs a tracking temperature signal T ₀ ′; The difference between the main steam actual temperature signal T ₀ and the tracking temperature signal T ₀ ′ is used to obtain the second difference signal ΔT ₂ , and the difference between the second difference signal ΔT ₂ and the main steam set temperature signal T is obtained. the first difference signal ΔT ₁ .

Through the above design, in order to realize the direct control of the final main steam temperature, its internal model is obtained by fitting calculation, and the influence of the pure lag formed in the main steam temperature transmission process on the control effect is reduced according to the internal model control principle, so that the temperature The adjustment response is more timely. To reduce the influence of time lag in the control process, the above scheme adopts the internal model control method in the main loop to incorporate the final main steam temperature into the control system to stabilize the main steam temperature. And the main steam temperature is interfered with to improve the stability of the main steam temperature. The cumulative error is small, the control is reliable, and the robustness is strong.

Further, the third interference driving signal D ₀ is a steam flow signal outputted through the steam drum of the boiler.

Using the above scheme, the main steam temperature is directly incorporated into the control system by using the outer main circuit, which reduces the deviation accumulation under the independent control of each control section. The main steam temperature is directly controlled through the outer main circuit.

To further describe, the temperature reduction control module includes a first temperature reduction control module and a second temperature reduction control module, the first temperature reduction control module obtains the main steam temperature control signal T ₁ , and controls the first stage The desuperheating process of the desuperheater is controlled so as to change the first desuperheating temperature value t ₁ of the output steam of the first-stage desuperheater, and the first desuperheating control module also generates according to the first desuperheating temperature value t ₁ The first desuperheating steam temperature signal T ₃ ; the second desuperheating control module acquires the first desuperheating steam temperature signal T ₃ , and controls the desuperheating process of the secondary desuperheater, thereby changing the The second desuperheating temperature value t ₂ of the steam output by the second-stage desuperheater, and then change the second-stage superheated steam temperature value t ₃ , and the second desuperheating control module is also based on the second-stage superheated steam temperature value t ₃ Generate said main steam actual temperature signal T ₀ .

Through the above design, the control of the first-stage desuperheater and the second-stage desuperheater are controlled as a separate control system, which are used to quickly stabilize the outlet steam temperature of the two-stage desuperheater, and the steam temperature of the second-stage desuperheater is set. The fixed value is given by the output steam temperature of the first-stage desuperheater, and the temperature setting value of the first-stage desuperheater is given by the main controller. The cumulative error is small and the control is reliable.

To further describe, the first temperature reduction control module includes a first temperature reduction controller, a first compensation module and a first interference module, and the first temperature reduction controller obtains the third difference signal ΔT ₃ and outputs the first The desuperheating control signal a, the first-stage desuperheating water flow valve changes the valve opening according to the first desuperheating control signal a, thereby changing the first-stage desuperheating water flow rate, and then changing the value collected by the first temperature monitor The first desuperheating temperature value t ₁ ; the first interference module obtains the first interference driving signal, and outputs the first interference signal d, and the first steam monitoring temperature is obtained by making a difference from the first interference signal d The first desuperheating steam temperature signal T ₃ ; the first compensation module obtains a first compensation driving signal, and outputs a first compensation signal c, the main steam temperature control signal T ₁ and the first desuperheating steam The temperature signal T ₃ and the first compensation signal c are sequentially subtracted to obtain the third difference signal ΔT ₃ .

With the above scheme, when the first disturbance signal d and the first compensation signal c act on the primary desuperheater, the first desuperheater controller responds quickly, and the internal model controller and the second desuperheater control module also respond The response of the two-stage desuperheater makes the outlet steam temperature quickly stabilize at the same temperature. The influence of the first stage desuperheater desuperheating process on the main steam temperature is weakened.

To further describe, the first disturbance driving signal is either the difference of the steam flow signal at the steam output port of the primary desuperheater at two adjacent moments, or the water flowing through the primary desuperheater at two adjacent moments The difference value of the water flow signal of the flow valve; the first compensation driving signal is either the difference value of the steam flow signal of the steam output port of the primary desuperheater at two adjacent moments, or the Describe the water flow signal difference of the first-stage desuperheating water flow valve.

Using the above scheme, according to different actual situations, avoid the fluctuation caused by the difference of the water flow signal flowing through the first-stage desuperheating water flow valve or the difference of the steam flow signal of the steam output port of the first-stage desuperheater on the desuperheating process. When there is a difference in water flow or steam volume, appropriate compensation and interference are performed on the desuperheating process of the primary desuperheater to enhance the stability of the desuperheater control of the primary desuperheater.

To further describe, the second temperature reduction control system includes a second temperature reduction controller, a second compensation module and a second interference module, and the second temperature reduction controller obtains the fourth difference signal ΔT ₄ and outputs the second The desuperheating control signal b, the two-stage desuperheating water flow valve controls the valve opening according to the second desuperheating control signal b, thereby changing the two-stage desuperheating water flow rate, and then changing the value collected by the second temperature monitor The second desuperheating temperature value t ₂ ; the second interference module obtains a second disturbance driving signal, and outputs a second disturbance signal f, and the second desuperheating temperature value t _{2 operates} with the second disturbance signal f After the difference, the second desuperheating steam temperature signal T ₄ is obtained; the second compensation module obtains the second compensation driving signal, and outputs a second compensation signal h, and the first desuperheating steam temperature signal T ₃ and the The second desuperheating steam temperature signal T ₄ and the second compensation signal h are sequentially subtracted to obtain the fourth difference signal ΔT ₄ .

When the second disturbance signal f and the second compensation signal h act on the secondary desuperheater, the second desuperheater controller responds quickly, and the internal model controller and the first desuperheater controller also respond accordingly, so that The outlet steam temperature of the two-stage desuperheater is quickly stabilized at the same temperature. Weaken the influence of the secondary desuperheater desuperheater control process on the main steam temperature.

To further describe, the second disturbance driving signal is either the difference of the steam flow signal at the steam output port of the secondary desuperheater at two adjacent moments, or the water flowing through the secondary desuperheater at two adjacent moments The difference of the water flow signal of the flow valve; the second compensation drive signal is either the difference of the steam flow signal of the steam output port of the secondary desuperheater at two adjacent moments, or the difference of the steam flow through the steam outlet at two adjacent moments Describe the water flow signal difference of the two-stage desuperheating water flow valve.

For different actual situations, avoid fluctuations in the desuperheating process caused by the difference of the water flow signal flowing through the secondary desuperheating water flow valve or the steam flow signal difference of the steam output port of the secondary desuperheater. Or when there is a difference in steam volume, appropriate compensation and interference are performed on the desuperheating process of the secondary desuperheater to enhance the stability of the desuperheater control of the secondary desuperheater.

To further describe, the main steam system is also provided with an adaptive PID correction module, the adaptive PID correction module takes input temperature deviation e and deviation change rate e _c as input, and the adaptive PID controller outputs parameter increment Signal Δk to the internal model controller;

The input temperature deviation e is the difference between the main steam set temperature signal T and the main steam actual temperature signal T ₀ ; the deviation change rate

Through the above design, the online real-time correction of the main loop controller parameters is realized. By introducing a fuzzy intelligent online correction unit, the temperature deviation of the main steam is analyzed. When the operating condition of the unit changes and the main steam temperature deviates from the set value range, the corresponding controller parameter correction value is given by the fuzzy intelligent online correction unit, and The new dynamic setting value of the controller is obtained after being superimposed with the original basic parameter setting value of the main controller, so as to realize the dynamic correction of the controller parameters. After the parameter correction, the controller outputs the appropriate control amount to the actuator according to the input deviation calculation, so as to control the main steam temperature, so as to improve the conventional control method. When the working conditions change, the fixed controller parameters can not be better. The disadvantage of controlling the main steam temperature makes the system have better adaptability.

Beneficial effects of the present invention:

Two-stage control is adopted, and the control of the first-stage desuperheater and the second-stage desuperheater are used as two single inner loop control loops, which are respectively used to quickly stabilize the outlet steam temperature of the two-stage desuperheater and the steam temperature of the second-stage desuperheater The setting value is given by the outlet steam temperature of the first-stage desuperheater, and the temperature setting value of the first-stage desuperheater is given by the internal model controller. It can quickly eliminate the temperature fluctuation of the main steam caused by disturbance factors such as the fluctuation of the desuperheating water flow, so that the system can be quickly stabilized. The effective coordination of the spray desuperheaters of the two control sections is ensured.

The main steam temperature is directly incorporated into the control system through the main loop of the outer ring, which reduces the deviation accumulation under the independent control of each control section.

The main loop adopts the internal model control method, and the two single inner loop loops are equivalent to the generalized controlled objects, and the internal model is obtained through fitting calculations, and the pure lag caused by the main steam temperature transmission process is reduced according to the internal model control principle The impact on the control effect makes the temperature adjustment response more timely.

Realize the online real-time correction of the parameters of the main loop controller. By introducing an adaptive PID online correction module, the main steam temperature deviation is analyzed. When the operating conditions of the unit change and the main steam temperature deviates from the set value range, the corresponding controller parameter correction value is given by the adaptive PID online correction module. , and superimposed with the original basic parameter setting value of the internal model controller to obtain a new dynamic setting value of the controller, so as to realize the dynamic correction of the controller parameters. After the parameter correction, the controller outputs the appropriate control amount to the actuator according to the input deviation calculation, so as to control the main steam temperature, so as to improve the conventional control method. When the working conditions change, the fixed controller parameters can not be better. The disadvantage of controlling the main steam temperature makes the system have better adaptability.

Description of drawings

Fig. 1 is a schematic diagram of the main steam production process of a single-seat coal-fired boiler of the present invention;

Fig. 2 is main steam generating process flow chart of the present invention;

Fig. 3 is a block diagram of the internal model control system of the present invention;

Fig. 4 is a schematic diagram of internal model control of the present invention;

Fig. 5 is the equivalent structural diagram of internal model control of the present invention;

Fig. 6 is a block diagram of the double-single-inner-loop cascade control system for boiler main steam temperature of the present invention.

Fig. 7 is a block diagram of the self-adaptive PID correction module of the present invention.

detailed description

The specific implementation manner and working principle of the present invention will be further described in detail below in conjunction with the accompanying drawings.

It can be seen from Fig. 1 and Fig. 2 that a boiler main steam temperature multi-parameter intelligent control system includes a water supply system and a main steam system. The first-level superheater, the first-level desuperheater, the panel superheater, the second-level desuperheater, the second-level superheater and the steam header are set.

It can also be seen from Fig. 1 that a first temperature monitor is arranged at the steam output port of the first-stage desuperheater, and a second temperature monitor is arranged at the steam output port of the second-stage desuperheater, The steam output port of the secondary superheater is provided with a third temperature monitor, and the water supply system includes a water tank, the water in the water tank is transported to the boiler steam drum through a water feeder pump, and the water in the water tank is also pumped to the boiler drum. The water feeder pump and the first-stage desuperheating water flow valve are sent to the first-stage desuperheater, and the water in the water tank is also sent to the second-stage desuperheater through the water feeder pump and the second-stage desuperheating water flow valve.

Preferably, a first steam flowmeter is arranged at the steam outlet of the boiler drum. A second steam flow meter is arranged at the steam outlet of the primary desuperheater. A third steam flowmeter is arranged at the steam outlet of the secondary desuperheater.

Preferably, a first desuperheating water flow meter is arranged on the desuperheating water pipeline of the primary desuperheater. A second desuperheating water flow meter is arranged on the desuperheating water pipeline of the secondary desuperheater.

As can be seen from Fig. 3, the main steam system is also provided with a main steam control system, and the main steam control system includes an internal model controller, a temperature reduction control module, a third interference module and an internal model module; the internal model The controller acquires the _first difference signal ΔT ₁ and outputs the main steam temperature control signal T ₁ ; The temperature reduction process of the superheater is controlled, thereby changing the secondary superheated steam temperature value t ₃ of the output steam of the secondary superheater; the third interference module collects the third interference driving signal D ₀ and outputs the third interference signal g , the third interference signal g and the temperature value _t3 of the secondary superheated steam are differenced to obtain the actual temperature signal T ₀ of the main steam; the internal model module obtains the temperature control signal T ₁ of the main steam and outputs a tracking Temperature signal T ₀ ′; the difference between the actual main steam temperature signal T ₀ and the tracking temperature signal T ₀ ′ is used to obtain a second difference signal ΔT ₂ , and the second difference signal ΔT ₂ is the same as the set temperature of the main steam The first difference signal ΔT ₁ is obtained after the signal T is subtracted.

Among them, the principle of internal model control can be seen in conjunction with Fig. 4, and Fig. 4 is converted equivalently to obtain an equivalent structure diagram. See Figure 5 for details.

The closed loop system has:

If the models match, that is, G _p (s) = G _m (s), formula (1) can be simplified as:

Y(s) _{＝ Gc} (s)Gp(s)R(s)+[1- _Gc (s)Gm( _s )] _Gd (s)D(s) (2)

At this point if satisfied Then there are:

Equation (3) shows that the internal model controller can achieve unbiased tracking of the reference input. However, the ideal controller characteristic is at It is obtained under the condition that exists and can be realized by the controller G _c (s). However, due to the existence of time lag and inertia links in the control process, There will be a pure lead and a pure differential link, so the conventional internal model controller can be designed according to the following method:

1) Divide G _m (s) into two items, namely:

G _m (s) = G _{m +} (s) G _{m -} (s) (4)

Among them: G _m+ (s) is the part of the model containing pure hysteresis and unstable zero point, and G _m- (s) is the minimum phase part of the model.

2) Find the internal model controller:

G _c (s) = f (s) / G _{m -} (s) (5)

where f(s) is a low-pass filter whose form is

Among them, the λ filtering parameter is the only design parameter of the internal model controller.

Design of internal model PID controller considering first-order time-delay process

Controlled object transfer function model:

Take the filter as:

From formula (5), the internal model controller can be obtained as:

The corresponding feedback controller is:

In order to make equation (10) have the form of a PID controller, the time-delay term is approximated by the first-order Taylor series

e ^-τs ＝1-τs (11)

Therefore, the form of the internal model PID controller can be obtained as follows:

Obviously (12) has the form of PI controller.

In this embodiment, the temperature reduction control module includes a first temperature reduction control module and a second temperature reduction control module, and the first temperature reduction control module includes a first temperature reduction controller, a first compensation module and a first interference module, so The first desuperheating controller acquires the _third difference signal ΔT3 and outputs the first desuperheating control signal a, and the first-stage desuperheating water flow valve changes the valve opening according to the first desuperheating control signal a, thereby changing the flow rate of the first-stage desuperheating water, and then changing the first desuperheating temperature value t ₁ collected by the first temperature monitor; the first interference module acquires a first interference driving signal, and outputs a first interference signal d, The first desuperheating steam temperature signal T3 is obtained after the difference between the first steam monitoring temperature and the first interference signal _d ; the first compensation module obtains a first compensation driving signal and outputs a first compensation signal c. The third difference signal ΔT ₃ is obtained by sequentially making a difference between the main steam temperature control signal T ₁ , the first desuperheating steam temperature signal T ₃ , and the first compensation signal c. The main steam temperature control signal T ₁ is used as the minuend, and the first desuperheated steam temperature signal T ₃ and the first compensation signal c are used as the subtrahend.

The second temperature reduction control system includes a second temperature reduction controller, a second compensation module and a second interference module, and the second temperature reduction controller obtains a fourth difference signal ΔT ₄ and outputs a second temperature reduction control signal b. The two-stage desuperheating water flow valve controls the valve opening according to the second desuperheating control signal b, thereby changing the secondary desuperheating water flow rate, and then changing the second desuperheating water collected by the second temperature monitor. temperature value t ₂ ; the second interference module obtains a second interference driving signal, and outputs a second interference signal f, and the second temperature reduction temperature value t ₂ is subtracted from the second interference signal f to obtain the The second desuperheating steam temperature signal T ₄ ; the second compensation module obtains the second compensation drive signal, and outputs a second compensation signal h, the first desuperheating steam temperature signal T ₃ and the second desuperheating steam temperature signal T 4 The steam temperature signal T ₄ and the second compensation signal h are sequentially subtracted to obtain the fourth difference signal ΔT ₄ . Wherein the first desuperheating steam temperature signal T ₃ is used as the minuend, the second desuperheating steam temperature signal T ₄ and the second compensation signal h are used as the subtrahend.

In this embodiment, the first disturbance driving signal is the difference ΔD ₁ of the steam flow signal at the steam output port of the primary desuperheater at two adjacent time points.

In this embodiment, the first compensation driving signal is the difference ΔD ₁ of the steam flow signal of the steam output port of the primary desuperheater at two adjacent time points.

Among them, the steam flow signal difference of the steam output port of the primary desuperheater ΔD ₁ =D _1i -D _1(i-1) , where D _1i is the steam flow signal of the steam output port of the primary desuperheater at time t _i , D _1(i-1) is the steam flow signal of the steam output port of the primary desuperheater at time t _i-1 .

In this embodiment, the second disturbance driving signal is the difference ΔD ₂ of the steam flow signal at the steam output port of the secondary desuperheater at two adjacent moments.

In this embodiment, the second compensation driving signal may be the difference ΔD ₂ of the steam flow signal at the steam output port of the secondary desuperheater at two adjacent moments.

The steam flow signal difference ΔD ₂ =D _2i -D _2(i-1) at the steam output port of the secondary desuperheater at two adjacent moments, where D _2i is the steam output of the primary desuperheater at time t _i D _2(i-1) is the steam flow signal of the steam output port of the primary desuperheater at time t _i-1 .

In this embodiment, the third disturbance driving signal D ₀ is a steam flow signal flowing through the steam drum outputted by the boiler.

As can be seen from Figure 6, the main steam system is also provided with an adaptive PID correction module, the adaptive PID correction module takes the input temperature deviation e and the deviation change rate e _c as input, and the adaptive PID controller outputs parameter incremental signal Δk to the internal model controller;

The input temperature deviation e is the difference between the main steam set temperature signal T and the main steam actual temperature signal T ₀ ; the deviation change rate

It can be seen from Figure 6 that the working principle of the self-adaptive PID online correction module is: firstly, the inference rules are formulated according to the experience of the operator, and then the input steam temperature deviation signal is fuzzy processed, and the fuzzy intelligent online correction unit is based on the rules The corresponding decision-making results are calculated by reasoning, and the results are defuzzified to obtain the required parameter correction value, that is, the parameter correction value of the internal model PID controller of the main loop, and the correction value is compared with the basic set value of the internal model PID After being superimposed, it is used as the new dynamic setting value of the internal model PID, thereby completing the online correction of the controller parameters. The expression of the parameter correction is as follows

k _p =k′ _p +Δk _p

k _i =k′ ₁ +Δk _i

k _d =k′ _d +Δk _d

In the formula, k′ _p , k′ _i , k′ _d are the basic set values of the controller, Δk _p , Δk _i , Δk _d are the correction values, and k _p , _ki , k _d are the dynamic settings of the controller after correction value.

Among them, the inference rules of this scheme design are:

1) When E is NB and EC is also NB, that is, the deviation is negatively large and tends to continue to be large. The measured main steam temperature is higher than the set value of 540°C and the deviation continues to increase. In order to eliminate the existing negative large The deviation and the trend of becoming larger need to increase the parameter value of the controller ratio P. In order to prevent the integral saturation, the value of the integral I needs to be reduced. In order to avoid excessive overshoot, the differential D takes a small value or zero, that is, ΔKp is PB , ΔKi is NB, ΔKd is PS, so that the controller parameters are within the control requirements, so that the main steam temperature stabilizes quickly.

2) When E is ZO and EC is NS, that is, the deviation is zero and tends to increase. The measured main steam temperature is equal to the set value of 540°C but has an upward trend. At this time, the value of controller P should be increased to improve the response speed , Properly reducing the value of the integral I improves the stability of the system, taking an appropriate value for the differential link reduces the oscillation during stability, that is, ΔKp is PS, ΔKi is NS, and ΔKd is NS.

3) When E is PB and EC is also PB, that is, the deviation is positive and has an increasing trend, and the measured main steam temperature is lower than the set value of 540°C and continues to decrease. In order to eliminate the existing positive deviation and suppress the further increase of the deviation, it is necessary to reduce the value of the controller P, and increase the value of the integral and differential of the controller, so that the system can obtain better steady-state performance, that is, ΔKp is NB, ΔKi is PB, and ΔKd is PB.

By analyzing various situations one by one, the fuzzy rule table of the controller parameter fuzzy intelligent online correction unit can be obtained, as shown in the following tables 1-3:

Table 1 Fuzzy rule table of ΔK _p

Table 2 Fuzzy rule table of ΔK _i

Table 3 Fuzzy rule table of ΔK _d

In this scheme, e and ec are input temperature deviation and deviation change rate, and E and EC are temperature deviation and deviation change rate after fuzzy processing. NB (Negative Big, Negative Big), NM (Negative Medium, Negative Medium), NS (Negative Small, Negative Small), ZO (Zero, Zero), PS (Positive Small, Postive Small), PM (Positive Medium, Postive Medium) , PB (Positive Big, Postive Big).

It should be noted that the above description is not intended to limit the present invention, and the present invention is not limited to the above-mentioned examples. Those skilled in the art may make changes, modifications, additions or replacements within the scope of the present invention. It should also belong to the protection scope of the present invention.

Claims (8)

1. a kind of Boiler Steam Temperature many reference amounts intelligence control system, including water supply system and main steam system, the main steaming Vapour system is provided with primary superheater, the one-level desuperheat set gradually on boiler-steam dome, and boiler-steam dome output steam gas circuit Device, pendant superheater, two grades of attemperators, two-stage superheater and steam collecting container, at the steam outlet of the one-level attemperator The first temperature monitoring is provided with, second temperature monitor is provided with the steam outlet of two grades of attemperators, it is described Two-stage superheater steam outlet is provided with the 3rd temperature monitoring, and the water supply system includes the water in water tank, the water tank The water being pumped into through feeding engine in the boiler-steam dome, the water tank is also conveyed through feed water pump, one-level attemperation water flow valve To one-level attemperator, the water in the water tank is also transported to two grades of attemperators through feed water pump, two grades of attemperation water flow valves, It is characterized in that：

The main steam system is additionally provided with main steam control system, and the main steam control system includes internal mode controller, subtracted Warm control module, the 3rd interference module and internal model module；

The internal mode controller obtains the first difference signal Δ T₁And export Main Steam Temperature Control signal T₁；

The attemperation control module is according to the Main Steam Temperature Control signal T₁Step by step to the one-level attemperator, two grades of desuperheats The desuperheating process of device is controlled, so as to change the secondary superheater steam temperature value t that the two-stage superheater exports steam₃；

Drive signal D is disturbed in the 3rd interference module collection the 3rd₀And export the 3rd interference signal g, the 3rd interference signal g With the secondary superheater steam temperature value t₃The main steam actual temperature signal T is obtained after making difference₀；

The internal model module obtains the Main Steam Temperature Control signal T₁And output tracking temperature signal T₀’；The main steaming Vapour actual temperature signal T₀With the tracking temperature signal T₀' make difference after obtain the second difference signal Δ T₂, second difference signal ΔT₂The first difference signal Δ T is obtained after making difference with main steam design temperature signal T₁。

2. Boiler Steam Temperature many reference amounts intelligence control system according to claim 1, it is characterised in that：Described 3rd Disturb drive signal D₀To flow through the steam flow signal of the boiler-steam dome output.

3. Boiler Steam Temperature many reference amounts intelligence control system according to claim 1 or 2, it is characterised in that：It is described Attemperation control module includes the first attemperation control module and the second attemperation control module, and the first attemperation control module obtains institute State Main Steam Temperature Control signal T₁, and the desuperheating process of the one-level attemperator is controlled, so as to change the one-level Attemperator exports the first desuperheat temperature value t of steam₁, the first attemperation control module is always according to the first desuperheat temperature value t₁It is raw Into the first desuperheated system temperature signal T₃；

The second attemperation control module obtains the first desuperheated system temperature signal T₃, and two grades of attemperators are subtracted Warm process is controlled, so as to change the second desuperheat temperature value t that two grades of attemperators export steam₂, and then change described Secondary superheater steam temperature value t₃, the second attemperation control module is always according to the secondary superheater steam temperature value t₃Generation institute State main steam actual temperature signal T₀。

4. Boiler Steam Temperature many reference amounts intelligence control system according to claim 3, it is characterised in that：Described first Attemperation control module includes the first attemperation control device, the first compensating module and the first interference module, the first attemperation control device Obtain the 3rd difference signal Δ T₃And the first attemperation control signal a is exported, the one-level attemperation water flow valve is according to described first Attemperation control signal a changes valve opening, so as to change one-level attemperation water flow, and then changes first temperature monitoring The first desuperheat temperature value t of collection₁；

First interference module obtains first and disturbs drive signal, and exports the first interference signal d, the first steam monitoring Temperature obtains the first desuperheated system temperature signal T after making difference with the first interference signal d₃；

First compensating module obtains first and compensates drive signal, and exports the first thermal compensation signal c, the main steam temperature control Signal T processed₁With the first desuperheated system temperature signal T₃, the first thermal compensation signal c make to obtain the 3rd difference letter successively after difference Number Δ T₃。

5. Boiler Steam Temperature many reference amounts intelligence control system according to claim 4, it is characterised in that：Described first Drive signal or the steam flow signal difference for one-level attemperator steam outlet described in the two neighboring moment are disturbed, or is phase Adjacent two moment flow through the water flow signal difference of the one-level attemperation water flow valve；

The first compensation drive signal is believed for the steam flow of one-level attemperator steam outlet described in the two neighboring moment Number difference, or flow through for the two neighboring moment water flow signal difference of the one-level attemperation water flow valve.

6. Boiler Steam Temperature many reference amounts intelligence control system according to claim 4, it is characterised in that：Described second Attemperation control system includes the second attemperation control device, the second compensating module and the second interference module, the second attemperation control device Obtain the 4th difference signal Δ T₄And the second attemperation control signal b is exported, two grades of attemperation water flow valves are according to described second Attemperation control signal b carrys out control valve aperture, so as to change two grades of attemperation water flows, and then changes the second temperature monitor The second desuperheat temperature value t of collection₂；

Second interference module obtains second and disturbs drive signal, and exports the second interference signal f, the second desuperheat temperature Value t₂The second desuperheated system temperature signal T is obtained after making difference with the second interference signal f₄；

Second compensating module obtains second and compensates drive signal, and exports the second thermal compensation signal h, first desuperheated system Temperature signal T₃With the second desuperheated system temperature signal T₄, the second thermal compensation signal h makees to obtain the 4th difference after difference successively Signal delta T₄。

7. Boiler Steam Temperature many reference amounts intelligence control system according to claim 6, it is characterised in that：Described second Drive signal or the steam flow signal difference for two grades of attemperator steam outlets described in the two neighboring moment are disturbed, or is phase Adjacent two moment flow through the water flow signal difference of two grades of attemperation water flow valves；

The second compensation drive signal or the steam flow letter for two grades of attemperator steam outlets described in the two neighboring moment Number difference, or flow through for the two neighboring moment water flow signal difference of two grades of attemperation water flow valves.

8. Boiler Steam Temperature many reference amounts intelligence control system according to claim 2, it is characterised in that：The main steaming Vapour system is additionally provided with self-adaptive PID correcting module, and the self-adaptive PID correcting module is become with input temp deviation e and deviation Rate e_cAs input, the self-adaptive PID controller output parameter increment signal Δ k to the internal mode controller；

The input temp deviation e is the main steam design temperature signal T and main steam actual temperature signal T₀Difference Value；The deviation variation rate