Denitration control signal accelerator, acceleration observation method and denitration control system

Abstract

The present application discloses a denitration control signal accelerator, an acceleration observation method and a denitration control system. The denitration control signal accelerator includes an input integrator, a positive feedback accelerator, a differentiator and a forward output controller. The input end of the input integrator is used to receive the denitration control signal, the output end of the input integrator is connected to the input end of the positive feedback accelerator, and the positive feedback accelerator is used to accelerate the output signal of the input integrator. The output end of the positive feedback accelerator is connected to the input end of the differentiator. The output end of the differentiator is connected to the input end of the forward output controller, and the output end of the forward output controller is used to output the denitration control acceleration signal corresponding to the denitration control signal. By converting the denitration control signal into an integral signal and accelerating the denitration control signal, an acceleration effect is accompanied at the start of zero deviation, reducing control lag, so as to be able to assist the denitration control system to maximize the reduction of nitrogen oxide deviation and enhance the control effect.

Description

Technical Field

[0001] The present application relates to the technical field of thermal power unit process control, and particularly relates to a denitration control signal accelerator, an acceleration observation method, and a denitration control system. Background Art

[0002] The denitration control system of a coal-fired thermal power unit is used to remove nitrogen oxides (NO X ) from the flue gas discharged by the boiler. X Currently, the denitration control system mainly has the problem of a large positive deviation of NO X , that is, the deviation of the NO X quantity relative to the NO X setpoint is large, resulting in an increase in the operating cost of the denitration control system.

[0003] Currently, in order to solve the problem of a large positive deviation of NO X , a proportional-integral controller (PI) is mainly used for control, but the PI cannot maximize the reduction of the NO Deviation, so it is necessary to provide an auxiliary control technology for the denitration control system.

[0004] The present application provides a denitration control signal accelerator, an acceleration observation method, and a denitration control system to solve the technical problem that the current PI cannot maximize the reduction of the NO X deviation.

[0005] To solve the above technical problems, in a first aspect, the present application provides a denitration control signal accelerator, including an input integrator, a positive feedback accelerator, a differentiator, and a positive output controller;

[0006] The input end of the input integrator is used to receive a denitration control signal, and the output end of the input integrator is connected to the input end of the positive feedback accelerator, and the positive feedback accelerator is used to accelerate the output signal of the input integrator;

[0007] The output end of the positive feedback accelerator is connected to the input end of the differentiator;

[0008] The output end of the differentiator is connected to the input end of the positive output controller, and the output end of the positive output controller is used to output a denitration control acceleration signal corresponding to the denitration control signal.

[0009] Preferably, the denitration control signal is a deviation signal between the nitrogen oxide signal and the nitrogen oxide setpoint signal of the denitration control system.

[0010] Preferably, the input integrator is:

[0011]

[0012] Among them, INI(s) is the transfer function of the input integrator, and T INI is the integration time constant of the input integrator, and s is the Laplace operator.

[0013] Preferably, the positive feedback accelerator includes a positive feedback link, an integration accelerator, and an integration limiter;

[0014] The input end of the positive feedback link is used to receive the denitration control signal and the output signal of the integration accelerator, and the output end of the positive feedback link is respectively connected to the input end of the differentiator and the input end of the integration accelerator;

[0015] The integration limiter is connected to the integration accelerator and is used to perform acceleration limiting on the integration accelerator.

[0016] Preferably, the integration limiter is:

[0017]

[0018] Among them, I(t) is the output signal of the integration accelerator, and T I is the integration time constant of the integration accelerator, and PV INI (t) is the output signal of the input integrator.

[0019] Preferably, the differentiator is:

[0020]

[0021] Among them, D(s) is the transfer function of the differentiator, and K D is the gain of the differentiator, and T D is the differentiation time constant of the differentiator, and s is the Laplace operator.

[0022] Preferably, the forward output controller is:

[0023]

[0024] Among them, FOC(t) is the output signal of the forward input controller, and D(t) is the output signal of the differentiator.

[0025] In a second aspect, the present application provides an acceleration observation method for a denitration control signal, including:

[0026] Input a unit step input signal into a third-order inertial process to obtain a process signal;

[0027] Input the process signal into the denitration control signal accelerator as described in the first aspect to obtain a denitration control acceleration signal.

[0028] In a third aspect, the present application provides a denitration control system, including a controller, the controller includes a cascade proportional controller, a conventional integrator, a negative proportional link, an addition link, and a denitration control signal accelerator as described in the first aspect;

[0029] The input end of the cascade proportional controller is used to receive a denitration control signal, the denitration control signal is a deviation signal between the nitrogen oxide signal and the nitrogen oxide set signal of the denitration control system, the output end of the cascade proportional controller is respectively connected to the input end of the conventional integrator and the input end of the addition link, the output end of the conventional integrator is connected to the input end of the denitration control signal accelerator, the output end of the denitration control signal accelerator is connected to the input end of the addition link, the output end of the addition link is connected to the input end of the negative proportional link, and the output end of the negative proportional link is used to output an accelerated denitration control signal;

[0030] The controller is:

[0031] C(s) = K cpc [1 + ISA(s)];

[0032] where, C(s) is the transfer function of the controller, ISA(s) is the transfer function of the denitration control signal accelerator, and K cpc is the gain of the cascade proportional controller.

[0033] Preferably, the transfer function of the denitration control signal accelerator is:

[0034]

[0035] where, T INI is the integral time constant of the input integrator, is the Laplace operator, T I is the integral time constant of the integral accelerator, T D is the differential time constant of the differentiator, K D is the gain of the differentiator, INI(t) is the output signal of the input integrator, and I(t) is the output signal of the integral accelerator.

[0036] Compared with the prior art, the present application has at least the following beneficial effects:

[0037] The denitration control signal accelerator of the present application includes an input integrator, a positive feedback accelerator, a differentiator, and a forward output controller; the input end of the input integrator is used to receive a denitration control signal, the output end of the input integrator is connected to the input end of the positive feedback accelerator, and the positive feedback accelerator is used to accelerate the output signal of the input integrator; the output end of the positive feedback accelerator is connected to the input end of the differentiator; the output end of the differentiator is connected to the input end of the forward output controller, and the output end of the forward output controller is used to output a denitration control acceleration signal corresponding to the denitration control signal.

[0038] The denitration control signal is converted into a denitration control signal through the input integrator, and the denitration control signal is accelerated through the positive feedback accelerator to accompany the acceleration effect at the start of zero deviation, reducing the control lag. Therefore, the denitration control signal accelerator applied to the denitration control system can assist the denitration control system to maximize the reduction of nitrogen oxide deviation and enhance the control effect. Description of the Drawings

[0039] Figure 1 It is a schematic structural diagram of the denitration control signal accelerator shown in an embodiment of the present application;

[0040] Figure 2 It is a schematic structural diagram of the denitration control signal accelerator shown in another embodiment of the present application;

[0041] Figure 3 It is a schematic flowchart of the acceleration observation method shown in an embodiment of the present application;

[0042] Figure 4 It is a schematic diagram of the acceleration observation result shown in an embodiment of the present application

[0043] Figure 5 It is a schematic structural diagram of the denitration control system shown in an embodiment of the present application;

[0044] Figure 6 It is a schematic diagram of the control result of the denitration control system shown in an embodiment of the present application. Detailed Embodiments

[0045] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0046] It should be understood that the step numbers used in the text are only for convenient description and do not limit the execution order of the steps.

[0047] It should be understood that the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. As used in the specification of this application and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0048] The terms "comprising" and "including" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0049] The term "and / or" refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0050] Any process or method description described in this application can be understood to represent a module, segment or part of code including one or more executable instructions for implementing a specific logical function or process, and the scope of the preferred embodiments of this application includes additional implementations, where the functions can be executed in a substantially simultaneous manner or in the reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the technical field to which the embodiments of this application belong.

[0051] The logic and / or steps described in this application, for example, can be considered as a defined sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus or device (such as a computer-based system, a system including a processor, or other systems that can fetch instructions from the instruction execution system, apparatus or device and execute the instructions), or in combination with these instruction execution systems, apparatus or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by or in combination with an instruction execution system, apparatus or device.

[0052] Please refer to Figure 1 , Figure 1 FIG. [FIGURE NUMBER] is a schematic structural diagram of a denitration control signal accelerator provided for the embodiments of this application. The denitration control signal accelerator of the embodiments of this application can be integrated into a computer device, and the computer device includes but is not limited to devices such as smart phones, laptop computers, tablet computers, desktop computers, physical servers and cloud servers. As Figure 1 shown, the denitration control signal accelerator of this embodiment includes an input integrator 11, a positive feedback accelerator 12, a differentiator 13 and a forward output controller 14;

[0053] Note: In the above translation, [FIGURE NUMBER] should be replaced with the actual figure number in the original text. If there is no specific figure number provided in the original text, it can be left as it is or adjusted according to the actual situation.The input end of the input integrator 11 is used to receive the denitration control signal. The output end of the input integrator 11 is connected to the input end of the positive feedback accelerator 12, and the positive feedback accelerator 12 is used to accelerate the output signal of the input integrator.

[0054] The output end of the positive feedback accelerator 12 is connected to the input end of the differentiator 13.

[0055] The output end of the differentiator 13 is connected to the input end of the positive output controller 14, and the output end of the positive output controller 14 is used to output the denitration control acceleration signal corresponding to the denitration control signal.

[0056] In this embodiment, the input signal (denitration control signal) is converted into a denitration control signal through the input integrator, so as to facilitate the use of the positive feedback accelerator to accelerate the denitration control signal, thereby facilitating subsequent deviation control in cooperation with conventional integrators such as the proportional-integral controller. Among them, by observing the acceleration of the denitration control signal through the positive feedback accelerator, the deviation of the given system process can be stably and quickly suppressed. Taking a thermal power unit as an example, it takes a certain amount of time for nitrogen oxides to change from zero deviation to a certain positive deviation. And the positive feedback accelerator of the present application has an accelerating effect, so that the amount of nitrogen oxides decreases with the acceleration of the positive feedback accelerator after starting from zero deviation, thus reducing the control lag problem. Therefore, it has a good effect on suppressing nitrogen oxides in the denitration control system.

[0057] Optionally, the denitration control signal is a deviation signal between the nitrogen oxide signal of the denitration control system and the nitrogen oxide given signal.

[0058] Optionally, the input integrator is:

[0059]

[0060] where INI(s) is the transfer function of the input integrator, T INI is the integration time constant of the input integrator, and s is the Laplace operator.

[0061] In some embodiments, as Figure 2 shown, the positive feedback accelerator 12 includes a positive feedback link 121, an integration accelerator 122, and an integration limiter 123;

[0062] The input end of the positive feedback link 121 is used to receive the denitration control signal and the output signal of the integration accelerator 122. The output end of the positive feedback link 121 is respectively connected to the input end of the differentiator 13 and the input end of the integration accelerator 122.

[0063] The integral limiter 123 is connected to the integral accelerator 122 and is used to perform acceleration limiting on the integral accelerator 122.

[0064] In this embodiment, an integral limiter is introduced on the basis of the integral accelerator to avoid the problem that the integral accelerator does not converge when controlling the output in the positive feedback link, and to ensure the convergence of the signal output.

[0065] Optionally, the integral accelerator is:

[0066]

[0067] where I(s) is the transfer function of the integral accelerator, s is the Laplace operator, and T I is the integral time constant of the integral accelerator.

[0068] Optionally, the integral limiter is:

[0069]

[0070] where I(t) is the output signal of the integral accelerator, T I is the integral time constant of the integral accelerator, and PV INI (t) is the output signal of the input integrator.

[0071] Optionally, the differentiator is:

[0072]

[0073] where D(s) is the transfer function of the differentiator, K D is the gain of the differentiator, T D is the differential time constant of the differentiator, and s is the Laplace operator.

[0074] Optionally, the forward output controller is:

[0075]

[0076] where FOC(t) is the output signal of the forward input controller, and D(t) is the output signal of the differentiator.

[0077] Please refer to Figure 3 , which shows a schematic flow chart of an acceleration observation method for denitration control signals provided by this application. As Figure 3 shown, the method includes:

[0078] Step S301: Input a unit step input signal into a third-order inertial process to obtain a process signal;

[0079] Step S302: Input the process signal into the denitration control signal accelerator as shown in Figure 1 or Figure 2 to obtain the denitration control acceleration signal.

[0080] In this embodiment, the deviation signal between the process output signal and the given signal of the three-order inertia process (TOIP) under a unit step input is observed for the denitration control signal acceleration.

[0081] Among them, the three-order inertia process TOIP is:

[0082]

[0083] TOIP(s) is the transfer function of the three-order inertia process TOIP, and T TOIP is the TOIP time constant, with the unit of s.

[0084] As an example rather than a limitation, when T INI = T I = 100 s, T D = 100 s, K D = 4, T TOIP = 100 s, the TOIP input is a unit step signal, the process set value is 1 (dimensionless), and the observed results of the output signal of the input integrator INI and the output signal of the denitration control signal accelerator ISA between the TOIP process output signal and the process set signal are as shown in Figure 4 . PV INI (t) is the output signal of the input integrator, and PV ISA (t) is the output signal of the ISA for the accelerated observation of PV INI (t). It can be seen that the output signal of the ISA significantly leads the output signal of the INI.

[0085] Please refer to Figure 5 , and this application also provides a structural schematic diagram of a denitration control system. As shown in Figure 5 , the system includes a controller (Controller, C) and a control process (Controller Process, CP). The controller includes a cascade proportional controller CPC, a conventional integrator I, a negative proportional link (-1), an addition link A, and a denitration control signal accelerator ISA as shown in Figure 1 or Figure 2 ;

[0086] The input end of the cascade proportional controller is used to receive the denitration control signal, which is the deviation signal between the nitrogen oxide signal of the denitration control system and the nitrogen oxide setpoint signal. The output end of the cascade proportional controller is respectively connected to the input end of the conventional integrator and the input end of the adder. The output end of the conventional integrator is connected to the input end of the denitration control signal accelerator. The output end of the denitration control signal accelerator is connected to the input end of the adder. The output end of the adder is connected to the input end of the negative proportional link. The output end of the negative proportional link is used to output the accelerated denitration control signal;

[0087] The controller is:

[0088] C(s) = K cpc [1 + ISA(s)];

[0089] where C(s) is the transfer function of the controller, ISA(s) is the transfer function of the denitration control signal accelerator, and K cpc is the gain of the cascade proportional controller.

[0090] Optionally, the transfer function of the denitration control signal accelerator is:

[0091]

[0092] where T INI is the integral time constant of the input integrator, s is the Laplace operator, T I is the integral time constant of the integral accelerator, T D is the differential time constant of the differentiator, K D is the gain of the differentiator, INI(t) is the output signal of the input integrator, and I(t) is the output signal of the integral accelerator.

[0093] As an example rather than a limitation, applying the controller C to the denitration control of a 1000MW ultra-supercritical thermal power unit in a certain power plant, the control results are obtained as Figure 5 shown. The denitration control signal accelerator ISA is added after 11:00. Before adding ISA, the positive deviation of NOx is 4.7 mg / m3 relative to the NOx setpoint; after adding ISA, the positive deviation of NOx is 2.2 mg / m3 relative to the NOx setpoint. It can be seen that ISA has a good effect on reducing the positive deviation of NOx.

[0094] In several embodiments provided in the present application, it can be understood that each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, the program segment, or the part of code includes one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved.

[0095] If the above functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a terminal device to execute all or part of the steps of the methods described in the various embodiments of the present application. The foregoing storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs.

[0096] The specific embodiments described above further elaborate on the purpose, technical solution, and beneficial effects of the present application. It should be understood that the above description is only for the specific embodiments of the present application and is not used to limit the protection scope of the present application. It is particularly pointed out that for those skilled in the art, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A denitration control signal accelerator, characterized in that, It includes an input integrator, a positive feedback accelerator, a differentiator, and a forward output controller; The input end of the input integrator is used to receive a denitration control signal. The output end of the input integrator is connected to the input end of the positive feedback accelerator, and the positive feedback accelerator is used to accelerate the output signal of the input integrator; The output end of the positive feedback accelerator is connected to the input end of the differentiator; The output end of the differentiator is connected to the input end of the forward output controller, and the output end of the forward output controller is used to output a denitration control acceleration signal corresponding to the denitration control signal; Among them, the forward output controller is: Among them, FOC(t) is the output signal of the forward output controller, and D(t) is the output signal of the differentiator; The positive feedback accelerator includes a positive feedback link, an integral accelerator, and an integral limiter. The integral accelerator is: Among them, I(s) is the transfer function of the integrating accelerator, s is the Laplace operator, and T I is the integration time constant of the integrating accelerator; The input end of the positive feedback link is used to receive the denitration control signal and the output signal of the integral accelerator. The output end of the positive feedback link is respectively connected to the input end of the differentiator and the input end of the integral accelerator; The integral limiter is connected to the integral accelerator and is used to perform acceleration limiting on the integral accelerator.

2. The denitration control signal accelerator according to claim 1, wherein The denitration control signal is the deviation signal between the nitrogen oxide signal and the nitrogen oxide set signal of the denitration control system.

3. The denitration control signal accelerator according to claim 1, characterized in that, The input integrator is: where, INI(s) is the transfer function of the input integrator, T INI is the integration time constant of the input integrator, and s is the Laplace operator.

4. The denitration control signal accelerator according to claim 1, characterized in that, The integral limiter is: where I(t) is the output signal of the integral accelerator, and T I is the integral time constant of the integral accelerator, and PV INI (t) is the output signal of the input integrator.

5. The denitration control signal accelerator according to claim 1, characterized in that, The differentiator is: where D(s) is the transfer function of the differentiator, and K D is the gain of the differentiator, T D is the differentiation time constant of the differentiator, and s is the Laplace operator.

6. An acceleration observation method for denitration control signals, characterized in that, It includes: Input a unit step input signal into a third-order inertial process to obtain a process signal; Input the process signal into the denitration control signal accelerator as described in any one of claims 1 to 5 to obtain a denitration control acceleration signal.

7. A denitration control system, characterized in that, It includes a controller. The controller includes a cascade proportional controller, a conventional integrator, a negative proportional link, an addition link, and the denitration control signal accelerator as described in any one of claims 1 to 5; The input end of the cascade proportional controller is used to receive a denitration control signal. The denitration control signal is the deviation signal between the nitrogen oxide signal and the nitrogen oxide set signal of the denitration control system. The output end of the cascade proportional controller is respectively connected to the input end of the conventional integrator and the input end of the addition link. The output end of the conventional integrator is connected to the input end of the denitration control signal accelerator. The output end of the denitration control signal accelerator is connected to the input end of the addition link. The output end of the addition link is connected to the input end of the negative proportional link. The output end of the negative proportional link is used to output the accelerated denitration control signal; The controller is: C(s) = K cpc [1 + ISA(s)]; Among them, C(s) is the transfer function of the controller, ISA(s) is the transfer function of the denitration control signal accelerator, and K cpc is the gain of the cascade proportional controller.

8. The denitration control system according to claim 7, wherein, The transfer function of the denitration control signal accelerator is: where T INI is the integration time constant of the input integrator, s is the Laplace operator, and T I is the integration time constant of the integration accelerator, and T D is the differentiation time constant of the differentiator, K D is the gain of the differentiator, PV INI (t) is the output signal of the input integrator, and I(t) is the output signal of the integration accelerator.

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