Forward differential accelerator and first-stage superheated steam temperature control system

Abstract

The present application discloses a forward differential accelerator and a first-stage superheated steam temperature control system. The input end of a first differentiator is used to receive an input signal. The output end of the first differentiator is connected to the input end of a positive feedback accelerator and the input end of an addition link, respectively. The positive feedback accelerator is used to accelerate the output signal of the first differentiator. The output end of the positive feedback accelerator is connected to the input end of a second differentiator. The output end of the second differentiator is connected to the input end of a forward output controller. The output end of the forward output controller is connected to the input end of the addition link. The output end of the addition link is used to output a forward differential acceleration signal. This enables the early output of positive signals with an upward trend in process signals, thereby performing forward overtemperature control in advance and reducing control lag. This can solve the forward overtemperature problem existing in the first-stage superheated steam temperature control system and enhance the control effect.

Description

Technical Field

[0001] The present application relates to the technical field of process control of thermal power units, and in particular to a forward differential accelerator and a first-stage superheated steam temperature control system. Background Art

[0002] In the practical control of thermal power plant processes, the primary superheated steam temperature control system often experiences large deviations in the primary superheated steam temperature. This means that the primary superheated steam temperature deviates significantly from the set value. Positive overtemperature (i.e., the primary superheated steam temperature exceeds the set value) is a more serious problem in primary superheated steam temperature control systems.

[0003] Currently, the existing technology for addressing the positive overtemperature problem in the first-stage superheated steam temperature control system uses a one-position control method. Specifically, when the positive deviation of the first-stage superheated steam temperature exceeds a certain level, the desuperheating water valve is opened at a fixed angle to control the water flow in and out of the valve, thereby achieving temperature control. However, this first-stage superheated steam temperature control system suffers from control lag, resulting in limited control effectiveness. Summary of the Invention

[0004] The present application provides a forward differential accelerator and a first-stage superheated steam temperature control system to solve the technical problem of control lag in the current first-stage superheated steam temperature control system.

[0005] In order to solve the above technical problems, in a first aspect, the present application provides a forward differential accelerator, comprising a first differentiator, a positive feedback accelerator, a second differentiator, a forward output controller and an addition link;

[0006] The input end of the first differentiator is used to receive an input signal, and the output end of the first differentiator is connected to the input end of the positive feedback accelerator and the input end of the addition link respectively, wherein the positive feedback accelerator is used to accelerate the output signal of the first differentiator;

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

[0008] The output end of the second differentiator is connected to the input end of the forward output controller;

[0009] The output end of the forward output controller is connected to the input end of the adding link, and the output end of the adding link is used to output a forward differential acceleration signal.

[0010] Preferably, the first differentiator is:

[0011]

[0012] Where DA(s) is the transfer function of the first differentiator, TDA is the differential time constant of the first differentiator, and s is the Laplace operator.

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

[0014] The input end of the positive feedback link is connected to the output end of the first differentiator and the output end of the integral accelerator respectively, and the output end of the positive feedback link is connected to the input end of the differentiator and the input end of the integral accelerator respectively;

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

[0016] Preferably, the integral accelerator is:

[0017]

[0018] The integral limiter is:

[0019]

[0020] Where I(s) is the transfer function of the integral accelerator, T I is the integration time constant of the integration accelerator, s is the Laplace operator, I(t) is the output signal of the integration accelerator, PV I (t) is the output signal of the first differentiator.

[0021] Preferably, the second differentiator is:

[0022]

[0023] Where DB(s) is the transfer function of the second differentiator, T DB is the differential time constant of the second differentiator, and s is the Laplace operator.

[0024] Preferably, the forward output controller is:

[0025]

[0026] Wherein, FOC(t) is the output signal of the forward output controller, and DB(t) is the output signal of the second differentiator.

[0027] Preferably, the addition step is:

[0028] A(t)=DA(t)+FOC(t);

[0029] Wherein, A(t) is the output signal of the adding link, DA(t) is the output signal of the first differentiator, and FOC(t) is the output signal of the forward output controller.

[0030] In a second aspect, the present application provides a first-stage superheated steam temperature control system, comprising a controller, wherein the controller comprises a cascade proportional controller, an engineering fastest integrator, and the forward differential accelerator as described in the first aspect;

[0031] The cascade proportional controller is connected to the engineering fastest integrator and the forward differentiator respectively, and the input signal of the cascade proportional controller is the deviation signal between the first-stage superheated steam temperature signal and the first-stage superheated steam temperature set signal of the first-stage superheated steam temperature system;

[0032] The controller is:

[0033] C(s)=K cpc [FDSA(s)+EFI(s)];

[0034] Where C(s) is the transfer function of the controller, EFI(s) is the transfer function of the engineering fastest integrator, FDSA(s) is the transfer function of the forward differential accelerator, and K cpc is the gain of the cascade proportional controller.

[0035] Preferably, the transfer function of the engineering fastest integrator is:

[0036]

[0037] Where EFPI(s) is the transfer function of the fastest engineering integrator, s is the Laplace operator, n is the order of the fastest engineering integrator, T EFI is the time constant of the fastest working integrator.

[0038] Preferably, the transfer function of the forward differential accelerator is:

[0039]

[0040]

[0041] Among them, T DA is the differential time constant of the first differentiator, s is the Laplace operator, I(t) is the output signal of the integral accelerator, T I is the integral time constant of the integral accelerator, T DB is the differential time constant of the second differentiator, K DB is the gain of the second differentiator, DA(t) is the output signal of the first differentiator, and DB(t) is the output signal of the second differentiator.

[0042] Compared with the prior art, this application has at least the following beneficial effects:

[0043] The forward differential accelerator of the present application includes a first differentiator, a positive feedback accelerator, a second differentiator, a forward output controller, and an addition link. The input end of the first differentiator is used to receive an input signal, and the output end of the first differentiator is connected to the input end of the positive feedback accelerator and the input end of the addition link, respectively, wherein the positive feedback accelerator is used to accelerate the output signal of the first differentiator. The output end of the positive feedback accelerator is connected to the input end of the second differentiator. The output end of the second differentiator is connected to the input end of the forward output controller. The output end of the forward output controller is connected to the input end of the addition link, and the output end of the addition link is used to output a forward differential acceleration signal. The present application uses a forward differential accelerator to forward accelerate the process signal so that the positive signal with an upward trend in the process signal is output in advance, thereby performing forward overtemperature control in advance and reducing control lag. This can solve the forward overtemperature problem existing in the first-stage superheated steam temperature control system and enhance the control effect.

[0044] In addition, the present application performs conditional limiting on the output of the integral accelerator through an integral limiter, and cooperates with the forward input controller and the second differentiator to solve the current control lag problem and output signal control in advance, thereby improving the first-level superheated steam temperature control effect of the first-level superheated steam temperature control system of the thermal power unit and suppressing forward overtemperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic structural diagram of a forward differential accelerator according to an embodiment of the present application;

[0046] Figure 2 This is a schematic structural diagram of a forward differential accelerator according to another embodiment of the present application;

[0047] Figure 3 Schematic diagram of the signal flow of the forward differential accelerator shown in the embodiment of the present application

[0048] Figure 4 This is a schematic diagram of the extraction results of the forward differential accelerator shown in an embodiment of the present application;

[0049] Figure 5 This is a schematic structural diagram of a first-stage superheated steam temperature control system according to an embodiment of the present application;

[0050] Figure 6 This is a schematic diagram of the control results of the first-stage superheated steam temperature control system shown in an embodiment of the present application. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0052] It should be understood that the step numbers used herein are only for convenience of description and are not intended to limit the order in which the steps are to be executed.

[0053] It should be understood that the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit this application. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0054] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0055] The term "and / or" refers to and includes any and all possible combinations of one or more of the associated listed items.

[0056] Any process or method description described in this application may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing specific logical functions or process steps, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed in a different order than shown or discussed, including performing functions in a substantially simultaneous manner or in a reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0057] The logic and / or steps described in this application, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied 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 system that can fetch instructions from and execute instructions on an instruction execution system, apparatus, or device), or in conjunction with such instruction execution system, apparatus, or device. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by an instruction execution system, apparatus, or device, or in conjunction with such instruction execution system, apparatus, or device.

[0058] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a forward differential accelerator provided in an embodiment of the present application. The forward differential accelerator in the embodiment of the present application can be integrated into a computer device, including but not limited to a smartphone, a laptop, a tablet computer, a desktop computer, a physical server, a cloud server, and other devices. Figure 1 As shown, the forward differential accelerator of this embodiment includes a first differentiator 11, a positive feedback accelerator 12, a second differentiator 13, a forward output controller 14 and an addition link 15;

[0059] The input end of the first differentiator 11 is used to receive an input signal, and the output end of the first differentiator 11 is connected to the input end of the positive feedback accelerator 12 and the input end of the adding link 15 respectively, wherein the positive feedback accelerator 12 is used to accelerate the output signal of the first differentiator 11;

[0060] The output end of the positive feedback accelerator 12 is connected to the input end of the second differentiator 13;

[0061] The output end of the second differentiator 13 is connected to the input end of the forward output controller 14;

[0062] The output end of the forward output controller 14 is connected to the input end of the adding link 15 , and the output end of the adding link 15 is used to output a forward differential acceleration signal.

[0063] In this embodiment, the input signal is a process signal, which is a deviation signal between the first-stage superheated steam temperature signal of the first-stage superheated steam temperature system and the first-stage superheated steam temperature given signal, so as to suppress the positive overtemperature of the first-stage superheated steam temperature control system.

[0064] Optionally, the first differentiator is:

[0065]

[0066] Where DA(s) is the transfer function of the first differentiator, T DA is the differential time constant of the first differentiator, and s is the Laplace operator.

[0067] In this optional embodiment, the input signal is input into the first differentiator so that the first differentiator extracts the positive signal from the input signal, thereby facilitating the subsequent advance extraction of the positive signal that affects the forward overtemperature, thereby enabling the control system to observe the input signal in advance and perform signal control, thereby reducing the control lag problem.

[0068] In some embodiments, as Figure 2 As shown, the positive feedback accelerator 12 includes a positive feedback link 121, an integral accelerator 122 and an integral limiter 123;

[0069] The input end of the positive feedback link 121 is connected to the output end of the first differentiator 11 and the output end of the integral accelerator 122 respectively, and the output end of the positive feedback link 121 is connected to the input end of the second differentiator 13 and the input end of the integral accelerator 122 respectively;

[0070] The integral limiter 123 is connected to the integral accelerator 122 and is used to perform acceleration limiting on the integral accelerator 122 .

[0071] In this embodiment, the signal output by the first differentiator is input into a positive feedback loop, which controls the acceleration of the integral accelerator. The positive signal in the signal output by the first differentiator is limited by an integral limiter, causing the integral accelerator to accelerate the positive signal. The positive acceleration signal output by the integral accelerator is conditionally limited by the integral limiter and fed back into the positive feedback loop. When the positive feedback loop confirms that the acceleration process of the integral accelerator has ended, the acceleration signal is input into a second differentiator, which extracts the differential signal from the acceleration signal. Finally, the differential signal is input into a forward output controller to extract the positive acceleration signal, thereby achieving forward acceleration.

[0072] Optionally, the integral accelerator is:

[0073]

[0074] The integral limiter is:

[0075]

[0076] Where I(s) is the transfer function of the integral accelerator, T I is the integration time constant of the integration accelerator, s is the Laplace operator, I(t) is the output signal of the integration accelerator, PV I (t) is the output signal of the first differentiator.

[0077] Optionally, the second differentiator is:

[0078]

[0079] Where DB(s) is the transfer function of the second differentiator, T DB is the differential time constant of the second differentiator, and s is the Laplace operator.

[0080] In this optional embodiment, the second differentiator extracts the differential signal of the acceleration signal to enable the forward output controller to perform forward output.

[0081] Optionally, the forward output controller is:

[0082]

[0083] Wherein, FOC(t) is the output signal of the forward output controller, and DB(t) is the output signal of the second differentiator.

[0084] Optionally, the addition step is:

[0085] A(t)=DA(t)+FOC(t);

[0086] Wherein, A(t) is the output signal of the adding link, DA(t) is the output signal of the first differentiator, and FOC(t) is the output signal of the forward output controller.

[0087] In this optional embodiment, the output signal with an upward trend output by the forward output controller and the output signal of the first differentiator are synthesized through an addition link to generate a complete forward differential acceleration signal, thereby realizing advance extraction of the process signal, so that the control system can observe the process signal in advance and perform signal control in advance.

[0088] By way of example and not limitation, Figure 3 The signal flow diagram of the forward differential accelerator is shown in FIG. The forward differential signal acceleration observation of the unit step input signal of the three order inertia process (TOIP) is performed. Among them, the three order inertia process TOIP is:

[0089]

[0090] Where TOIP(s) is the transfer function of the third-order inertial process TOIP, T TOIP is the TOIP time constant, in s.

[0091] In T I =100s, T DA =T DB =100s, T TOIP = 100s, TOIP input is a unit step signal, and the process forward differential signal acceleration observation result is obtained, such as Figure 4 PV TOIP (t) is the output signal of the third-order inertial process TOIP under a positive unit step input, PV D：A (t) is the output signal of the first differentiator, PV FDSA (t) is the output signal of the forward differential accelerator. It can be seen that the process output signal of FDSA is significantly ahead of the process output signal of differentiator A.

[0092] See Figure 5 , this application also provides a structural diagram of a first-level superheated steam temperature control system. Figure 5 As shown, the system includes a controller (Controller, C) and a control process (Controller Process, CP), wherein the controller includes a cascade proportional controller CPC, an engineering fastest integrator EFI and Figure 1 or Figure 2 The forward differential accelerator FDSA;

[0093] The cascade proportional controller is connected to the engineering fastest integrator and the forward differentiator respectively, and the input signal of the cascade proportional controller is the deviation signal between the first-stage superheated steam temperature signal and the first-stage superheated steam temperature set signal of the first-stage superheated steam temperature system;

[0094] The controller is:

[0095] C(s)=K cpc [FDSA(s)+EFI(s)];

[0096] Where C(s) is the transfer function of the controller, EFI(s) is the transfer function of the engineering fastest integrator, FDSA(s) is the transfer function of the forward differential accelerator, and K cpc is the gain of the cascade proportional controller.

[0097] Optionally, the transfer function of the engineering fastest integrator is:

[0098]

[0099] Where EFPI(s) is the transfer function of the fastest engineering integrator, s is the Laplace operator, n is the order of the fastest engineering integrator, T EFI is the time constant of the fastest working integrator.

[0100] Optionally, the transfer function of the forward differential accelerator is:

[0101]

[0102] Among them, T DA is the differential time constant of the first differentiator, s is the Laplace operator, I(t) is the output signal of the integral accelerator, T I is the integral time constant of the integral accelerator, T Dt is the differential time constant of the second differentiator, K DB is the gain of the second differentiator, DA(t) is the output signal of the first differentiator, and DB(t) is the output signal of the second differentiator.

[0103] As an example and not a limitation, the controller C is applied to the primary superheated steam temperature control system of a 1000MW supercritical thermal power unit in a power plant, and the control results are as follows: Figure 6 As shown in the figure, after 11:00, the forward differential accelerator (FDSA) was added. Before the FDSA was added, the maximum positive deviation of the first-stage superheated steam temperature relative to the set value was 14.4°C. After the FDSA was added, the maximum positive deviation of the first-stage superheated steam temperature was 8.7°C. This shows that the FDSA is effective in suppressing positive deviations of the first-stage superheated steam temperature.

[0104] In several embodiments provided in the present application, it is understood that each box in the flow chart or block diagram can represent a part of a module, program segment or code, and the part of the module, program segment or code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which depends on the functions involved.

[0105] If the 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 this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the 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 enabling a terminal device to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, and other media that can store program codes.

[0106] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application by those skilled in the art should be included within the scope of protection of this application.

Claims

1. A forward differential accelerator, characterized in that: It includes a first differentiator, a positive feedback accelerator, a second differentiator, a forward output controller and an adding link; The input end of the first differentiator is used to receive an input signal, and the output end of the first differentiator is connected to the input end of the positive feedback accelerator and the input end of the addition link respectively, wherein the positive feedback accelerator is used to accelerate the output signal of the first differentiator; The output end of the positive feedback accelerator is connected to the input end of the second differentiator; The output end of the second differentiator is connected to the input end of the forward output controller; The output end of the forward output controller is connected to the input end of the adding link, and the output end of the adding link is used to output a forward differential acceleration signal; The positive feedback accelerator includes a positive feedback link, an integral accelerator and an integral limiter; The input end of the positive feedback link is connected to the output end of the first differentiator and the output end of the integral accelerator respectively, and the output end of the positive feedback link is connected to the input end of the second differentiator and the input end of the integral accelerator respectively; The integral limiter is connected to the integral accelerator and is used to perform acceleration limiting on the integral accelerator; The forward output controller is: Wherein, FOC(t) is the output signal of the forward output controller, and DB(t) is the output signal of the second differentiator.

2. The forward differential accelerator according to claim 1, wherein: The first differentiator is: Where DA(s) is the transfer function of the first differentiator, T DA is the differential time constant of the first differentiator, and s is the Laplace operator.

3. The forward differential accelerator according to claim 1, wherein: The integral accelerator is: The integral limiter is: Where I(s) is the transfer function of the integral accelerator, T I is the integration time constant of the integration accelerator, s is the Laplace operator, I(t) is the output signal of the integration accelerator, PV I (t) is the output signal of the first differentiator.

4. The forward differential accelerator according to claim 1, wherein: The second differentiator is: Where DB(s) is the transfer function of the second differentiator, T DB is the differential time constant of the second differentiator, and s is the Laplace operator.

5. The forward differential accelerator according to claim 1, wherein: The addition step is: A(t)=DA(t)+FOC(t); Wherein, A(t) is the output signal of the adding link, DA(t) is the output signal of the first differentiator, and FOC(t) is the output signal of the forward output controller.

6. A first-stage superheated steam temperature control system, characterized in that: comprising a controller comprising a cascade proportional controller, an engineering fastest integrator, and a forward differential accelerator according to any one of claims 1 to 5; The cascade proportional controller is connected to the engineering fastest integrator and the forward differential accelerator respectively, and the input signal of the cascade proportional controller is the deviation signal between the first-stage superheated steam temperature signal and the first-stage superheated steam temperature given signal of the first-stage superheated steam temperature system; The controller is: C(s)=K cpc [FDSA(s)+EFI(s)]; Where C(s) is the transfer function of the controller, EFI(s) is the transfer function of the engineering fastest integrator, FDSA(s) is the transfer function of the forward differential accelerator, and K cpc is the gain of the cascade proportional controller.

7. The primary superheated steam temperature control system according to claim 6, characterized in that: The transfer function of the engineering fastest integrator is: Where EFI(s) is the transfer function of the fastest engineering integrator, s is the Laplace operator, n is the order of the fastest engineering integrator, T EFI is the time constant of the fastest working integrator.

8. The primary superheated steam temperature control system according to claim 6, characterized in that: The transfer function of the forward differential accelerator is: Among them, T DA is the differential time constant of the first differentiator, s is the Laplace operator, I(t) is the output signal of the integral accelerator, T I is the integral time constant of the integral accelerator, T DB is the differential time constant of the second differentiator, K DB is the gain of the second differentiator, DA(t) is the output signal of the first differentiator, and DB(t) is the output signal of the second differentiator.

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