Multi-controller switching control method and device, storage medium and steam temperature control system

Abstract

The application provides a kind of multi-controller switching control method, device, storage medium and steam temperature control system, belongs to thermal automatic control technical field.The method includes: based on the value of scheduling variable, and using the applicability function constructed based on Gaussian function, the applicability of each controller of target steam temperature system is determined;Using the preset weight function, the applicability of each controller is normalized, and the weight of each controller is obtained;According to the error signal of target control quantity, the output of each controller is obtained;Based on the output of each controller and the weight of each controller, the fusion output is obtained, and the fusion output is converted into control instruction, and the multi-controller is switched control.The application uses Gaussian function as controller applicability function, realizes the smooth switching between multi-controller, fundamentally eliminates the control quantity jump problem.

Description

Technical Field

[0001] This invention relates to the field of thermal automatic control technology, and more specifically to a multi-controller switching control method, device, storage medium, and steam temperature control system. Background Technology

[0002] With the continuous increase in the proportion of new energy power generation, the demand for grid peak shaving is growing. As the main peak shaving resource, thermal power units need to operate stably within a wide load range. Under deep peak shaving conditions, the unit load drops from 100% of the rated load to 30% or even lower, with load changes exceeding 70%, posing a severe challenge to the steam temperature control system. Main steam temperature is a key parameter affecting unit efficiency and equipment safety. Excessive temperature can accelerate the creep of metal materials, while excessively low temperature will reduce unit efficiency and increase humidity. Therefore, steam temperature control is one of the core tasks of the thermal power unit control system.

[0003] In existing technologies, gain-based scheduling methods are commonly used to address changes in operating conditions. These methods adjust controller parameters or switch controllers online based on scheduling variables such as load or main steam flow. Existing gain-based scheduling techniques typically employ linear interpolation or triangular membership functions to achieve controller switching. However, linear interpolation only guarantees continuity at switching boundary points but is not differentiable. The continuous nature of the control variable leads to abrupt changes in its rate of change; the membership function of the triangle is also non-differentiable at the vertices, resulting in a jump in the rate of change. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-controller switching control method, device, storage medium, and steam temperature control system, aiming to achieve smooth switching control of the steam temperature system for deep peak shaving conditions.

[0005] To achieve the above objectives, embodiments of the present invention provide a multi-controller switching control method for a steam temperature system. The multi-controller switching control method includes: acquiring the values ​​of scheduling variables representing the current operating parameters of the target steam temperature system; determining the suitability of each controller in the target steam temperature system based on the acquired values ​​of the scheduling variables and using a suitability function constructed based on a Gaussian function; normalizing the determined suitability of each controller using a preset weight function to obtain the weight of each controller; obtaining the output quantity of each controller based on the error signal of the target control quantity of the target steam temperature system; and obtaining a fused output quantity based on the obtained output quantities of each controller and the weights of each controller, and converting the obtained fused output quantity into a control command to perform switching control on the multiple controllers.

[0006] In an optional implementation, before determining the suitability of each controller in the target steam temperature system using the suitability function constructed based on the Gaussian function, the multi-controller switching control method further includes: constructing a Gaussian function-based suitability function using the scheduling variable, the center point of each controller, and the width coefficient of the shape parameter used to characterize the suitability function. Wherein, the center point of each controller is the value of the scheduling variable corresponding to the preset operating condition of each controller.

[0007] In an optional implementation, the controller is represented by the following formula. applicability function :

[0008] in, Represents an exponential function. Represents the scheduling variable. Indicates controller The center point, This represents the width coefficient.

[0009] In an optional implementation, the multi-controller switching control method further includes: setting a rate-of-change constraint on the actuator of the target steam temperature system based on the Lipschitz constant constraint; and setting a limit constraint on the width coefficient based on the rate-of-change constraint on the actuator of the target steam temperature system.

[0010] In an optional implementation, the width coefficient is represented by the following formula. Boundary constraints:

[0011]

[0012] in, This represents the maximum distance between the center points of adjacent controllers. This represents the maximum difference in steady-state output between adjacent controllers. This represents the rate of change constraint of the scheduling variable. This indicates the rate of change constraint of the actuator. This represents the minimum distance between the center points of adjacent controllers. This represents the applicability decay threshold.

[0013] In an optional implementation, the multi-controller switching control method further includes: determining whether the fused output quantity satisfies the rate of change constraint of the actuator of the target steam temperature system; if the fused output quantity satisfies the rate of change constraint of the actuator of the target steam temperature system, then performing the step of converting the obtained fused output quantity into a control command to perform switching control on the multi-controller; and if the fused output quantity does not satisfy the rate of change constraint of the actuator of the target steam temperature system, then constraining the Lipschitz constant of the preset weighting function.

[0014] This invention also provides a control device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the computer program to implement the multi-controller switching control method described above.

[0015] This invention also provides a machine-readable storage medium storing instructions that cause a machine to execute the multi-controller switching control method described above.

[0016] This invention also provides a steam temperature control system, which includes multiple controllers, the aforementioned control device, and the actuator.

[0017] In an optional implementation, each of the plurality of controllers sets a center point according to a preset operating condition. The center point is the value of a scheduling variable corresponding to the preset operating condition of each controller.

[0018] The multi-controller switching control method for a steam temperature system provided by the present invention, through the above technical solution, includes: obtaining the values ​​of scheduling variables used to characterize the current operating parameters of the target steam temperature system; determining the suitability of each controller of the target steam temperature system based on the obtained values ​​of scheduling variables and using a suitability function constructed based on a Gaussian function; normalizing the determined suitability of each controller using a preset weight function to obtain the weight of each controller; obtaining the output of each controller based on the error signal of the target control quantity of the target steam temperature system; and obtaining a fused output quantity based on the obtained output quantity and weight of each controller, and converting the obtained fused output quantity into a control command to perform switching control on the multiple controllers. The present invention, by using a Gaussian function as the controller suitability function, achieves smooth switching between multiple controllers, fundamentally eliminating the problem of control quantity jumps; based on the normalized weight fusion mechanism, the system achieves smooth adaptive control strategy changes with operating conditions, eliminating control quantity jumps during switching, avoiding temperature fluctuations and prolonged adjustment time caused by switching, and significantly improving the stability of steam temperature control under deep peak shaving conditions.

[0019] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the multi-controller switching control method for a steam temperature system provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the framework for example multi-controller switching control provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of an example of multi-controller switching control provided in an embodiment of the present invention. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0022] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application all comply with the relevant provisions of national laws and regulations. In the embodiments of this application, certain existing industry solutions such as software, components, and models may be mentioned. These should be considered exemplary, intended only to illustrate the feasibility of implementing the technical solution of this application, and do not imply that the applicant has already used or necessarily used such solutions.

[0023] Please refer to Figure 1 This invention provides a multi-controller switching control method for a steam temperature system, which may include the following steps: Step S110: Obtain the values ​​of the scheduling variables used by the target steam temperature system to characterize the operating parameters under the current operating conditions.

[0024] In the embodiments of this application, please refer to Figure 2 scheduling variables The controlled variable is the current operating parameter (e.g., main steam flow rate, real-time steam temperature, etc.) used to characterize the target steam temperature system (which can be simply referred to as the system). For the physical quantity that needs to be controlled (e.g., main steam temperature and error), the control quantity is... To adjust the controlled variable's operating quantity, the actuator is a device that executes control commands. The system is configured with multiple controllers (e.g., Each controller is optimized for a specific operating point (i.e., the design operating point), achieving optimal control performance near its design operating point. The controller outputs are respectively... Through weight By performing weighted fusion, a fused output can be obtained. As input instructions for the actuator.

[0025] Please refer to Figure 2 and Figure 3 For example, obtaining the value of the scheduling variable means collecting the operating parameters of the current peak-shaving condition.

[0026] Step S120: Based on the obtained values ​​of the scheduling variables, and using the suitability function constructed based on the Gaussian function, determine the suitability of each controller of the target steam temperature system.

[0027] Wherein, the applicability function Using scheduling variables as independent variables, the controller is characterized. Applicability under current working conditions.

[0028] In a preferred embodiment of the present invention, before determining the suitability of each controller of the target steam temperature system using a suitability function constructed based on a Gaussian function, the multi-controller switching control method may further include: constructing a Gaussian function-based suitability function using scheduling variables, the center point of each controller, and a width coefficient representing the shape parameter of the suitability function. The center point of each controller is the value of the scheduling variable corresponding to the preset operating condition of each controller.

[0029] In a preferred embodiment of the present invention, the controller can be represented by the following formula. applicability function :

[0030] in, Represents an exponential function. Represents the scheduling variable. Indicates controller The center point, This represents the width coefficient.

[0031] This invention employs a Gaussian function as the suitability function for each controller (hereinafter referred to as the Gaussian suitability function) to achieve smooth switching between multiple controllers, fundamentally eliminating the problem of control variable jumps. Since the Gaussian function is infinitely differentiable, the weighting function and its derivatives are continuous throughout the entire scheduling variable range, and the fused output is also continuously differentiable, resulting in no jumps in the rate of change of the control variable and no disturbances during the switching process. Among these, the width coefficient... The shape parameter of the Gaussian fitness function determines the rate at which fitness decays with changes in scheduling variables. (Center point) For controller The scheduling variable value corresponding to the design condition represents the peak position of the applicability function. In this embodiment of the invention, when the scheduling variable equals the center point... When the scheduling variable deviates from the center point, the applicability reaches its maximum value of 1; when the scheduling variable deviates from the center point, the applicability decays smoothly, and the decay rate is determined by the width coefficient. Decide.

[0032] Please refer to Figure 2 and Figure 3 Following the example above, we can use equation (1) to calculate the suitability of each controller.

[0033] Step S130: Using a preset weighting function, normalize the applicability of each controller to obtain the weight of each controller.

[0034] In a preferred embodiment of the present invention, a preset weighting function is used. It can be obtained by normalizing the applicability, and can be expressed by the following formula:

[0035] in, For the number of controllers, Indicates controller .

[0036] In this embodiment of the invention, weight Indicates controller The contribution ratio of the output to the fused output satisfies the normalization condition. Therefore, normalization ensures that the sum of all weights is 1, guaranteeing the continuity of the fused output. When the scheduling variable approaches the center point of a controller, the suitability of that controller approaches 1, while the suitability of other controllers approaches 0. Consequently, the weight of that controller approaches 1, and the weights of other controllers approach 0. When the scheduling variable is between two center points, the weights of the two controllers can exhibit a smooth transition, with one increasing and the other decreasing.

[0037] Please refer to Figure 2 and Figure 3 Following the example above, we can use equation (2) to calculate the weights of each controller.

[0038] Step S140: Obtain the output of each controller based on the error signal of the target control quantity of the target steam temperature system.

[0039] Please refer to Figure 2 and Figure 3Following the example above, each controller can calculate its own output based on the error signal of the target control quantity (i.e., the controlled quantity).

[0040] Step S150: Based on the output quantities and weights of each controller, obtain the fused output quantity, and convert the obtained fused output quantity into control commands to switch the multiple controllers.

[0041] Fusion output Output to each controller Its corresponding weight The sum of the products of can be expressed by the following formula:

[0042] Therefore, since the weighting function is continuously differentiable and the fused output is also continuously differentiable, the rate of change of the control quantity does not jump, which can fundamentally eliminate the switching disturbance.

[0043] Please refer to Figure 2 and Figure 3 Following the example above, the outputs of each controller are multiplied by their corresponding weights and then summed to obtain the fused output. This fused output can be used as an input command for the actuator to regulate the controlled variable.

[0044] In a preferred embodiment of the present invention, the multi-controller switching control method may further include: setting a rate-of-change constraint on the actuator of the target steam temperature system based on the Lipschitz constant constraint; and setting a limit constraint on the width coefficient based on the rate-of-change constraint on the actuator of the target steam temperature system.

[0045] In this embodiment of the invention, the derivative property of the weighting function can be used to ensure that the rate of change of the fused output does not exceed the rate of change constraint (also known as the rate constraint or rate limit) of the actuator. The derivative of the weighting function with respect to the scheduling variable can be expressed as follows:

[0046] in, Let be the derivative of the fitness function with respect to the scheduling variable. The analytical expression for the derivative of the fitness function is given by the following equation:

[0047] As shown in equation (5), the derivative of the fitness function is directly proportional to the deviation between the scheduling variable and the centroid, and inversely proportional to the square of the width coefficient. The absolute value of the derivative... exist At this point, the value reaches its maximum. .

[0048] Therefore, the absolute value of the derivative of the weighting function has an upper bound. For two adjacent controllers... and In the interval midpoint At this point, the derivative of the weighting function reaches its maximum value: .

[0049] when When (ensuring overlap between the domains of the two controllers), this maximum value approximately satisfies the following:

[0050] in, Maximum distance between the center points of adjacent controllers (units) (Same as above), where L is the Lipschitz constant of the weighting function, reflecting the steepness of the weight change.

[0051] In a preferred embodiment of the present invention, the width coefficient can be expressed by the following formula. Boundary constraints:

[0052]

[0053] in, This represents the maximum distance between the center points of adjacent controllers. This represents the maximum difference in steady-state output between adjacent controllers. This represents the rate of change constraint of the scheduling variable. This indicates the rate of change constraint of the actuator. This represents the minimum distance between the center points of adjacent controllers. This represents the applicability decay threshold.

[0054] As mentioned earlier, the Lipschitz constant of the weighting function reflects the steepness of the weight change. In this embodiment of the invention, the rate constraint of the actuator can be transformed into a Lipschitz constant constraint. This is based on the rate of change constraint of the scheduling variable. Difference between steady-state output and adjacent controller The rate of change of the fused output satisfies: Ignoring internal controller dynamics, to ensure that the actuator rate limit is not exceeded. , must meet Combining equation (6), the width coefficient can be obtained. The lower bound is shown in equation (7). Equation (7) establishes the control algorithm parameters ( ) and physical constraints of the actuator ( ), system operation constraints ( ) explicit associations between.

[0055] In this embodiment of the invention, to prevent the width coefficient Excessive weighting of the width coefficient σ can lead to excessive overlap of the scopes of adjacent controllers, causing the system to remain in a multimodal "average" state for an extended period and lose its optimal performance at a single point. To address this, an upper bound constraint based on scope boundary decay can be established. Multimodality can be understood as a system state where multiple controllers simultaneously have non-zero weights, typically occurring in the transition region between the central points of adjacent controllers, where the system's control output is contributed collaboratively by multiple controllers. The multimodal "average" state can be understood as when the weights of two controllers are nearly equal (e.g., approximately 0.5 each), the fused output is a simple average of the two controller outputs, potentially causing the system to lose the optimal control performance of any controller at its design operating point. By appropriately setting an upper bound constraint on the width coefficient σ, this state can be avoided from persisting in the system for an extended period.

[0056] In this embodiment of the invention, an applicability decay threshold can be defined. (For example, the value is) ,Right now, When the applicability decays to a peak value of 1. When the value is multiplied, it serves as the boundary of the controller's scope. The midpoint of the line connecting the center points of two adjacent controllers is used as the boundary. The applicability is as follows:

[0057] In this embodiment of the invention, the value can be set to be no greater than the peak value. times, that is, The upper bound of the width coefficient can be obtained as shown in equation (8).

[0058] Therefore, equations (7) and (8) constitute The complete settings range, ensuring the selection... It satisfies the actuator rate limit while avoiding the degradation of control performance caused by excessive overlap of the action domain.

[0059] In a preferred embodiment of the present invention, the multi-controller switching control method may further include: determining whether the fused output quantity satisfies the rate of change constraint of the actuator of the target steam temperature system; if the fused output quantity satisfies the rate of change constraint of the actuator of the target steam temperature system, then performing the step of converting the obtained fused output quantity into a control command to perform switching control on the multi-controller; and if the fused output quantity does not satisfy the rate of change constraint of the actuator of the target steam temperature system, then constraining the Lipschitz constant of the preset weighting function.

[0060] Please refer to Figure 2 and Figure 3 The rate limit and width factor of the actuator The boundary constraints can be used to verify the system configuration during system initialization; or during system operation, to determine whether the fused output meets the rate of change constraint of the actuator of the target steam temperature system.

[0061] The rate limit of the actuator is a physical constraint, which can be expressed as:

[0062] in, The upper limit of the rate of change of the controlled quantity is determined by the physical characteristics of the actuator. For example, the stroke change rate of an electric control valve is limited by the motor speed, with a value such as... The movement speed of a hydraulic actuator is limited by the flow rate.

[0063] In this embodiment of the invention, the rate of change of the fused output may include weight changes and controller output changes, as shown in the following formula:

[0064] As shown in equation (11), the rate of change of the fused output is affected by the rate of change of the weights, the rate of change of the scheduling variables, and the rate of change of the controller output. Therefore, the contribution of the switching term to the rate of change of the fused output can be controlled by constraining the rate of change of the weights (i.e., constraining the Lipschitz constant).

[0065] In this embodiment of the invention, the rate of change of the scheduling variable is also limited by system operation constraints, as shown in the following formula:

[0066] in, This represents the upper limit of the rate of change of the scheduling variable. For example, the load change rate of thermal power units is limited by the ramp rate, with a value such as... .

[0067] Accordingly, the multi-controller switching control method for a steam temperature system provided in this embodiment of the invention includes: acquiring the values ​​of scheduling variables used to characterize the current operating parameters of the target steam temperature system; determining the suitability of each controller of the target steam temperature system based on the acquired values ​​of scheduling variables and using a suitability function constructed based on a Gaussian function; normalizing the determined suitability of each controller using a preset weight function to obtain the weight of each controller; obtaining the output of each controller based on the error signal of the target control quantity of the target steam temperature system; and obtaining a fused output quantity based on the obtained output quantities of each controller and the weight of each controller, and converting the obtained fused output quantity into a control command to perform switching control on the multiple controllers. This embodiment of the invention achieves smooth switching between multiple controllers by using a Gaussian function as the controller suitability function, fundamentally eliminating the problem of control quantity jumps; based on the normalized weight fusion mechanism, the system achieves smooth adaptive control strategy changes with operating conditions, eliminating control quantity jumps during switching, avoiding temperature fluctuations and prolonged adjustment time caused by switching, and significantly improving the stability of steam temperature control under deep peak shaving conditions.

[0068] Furthermore, this embodiment of the invention establishes a correlation between control algorithm parameters and physical constraints of the actuator, ensuring that the weight change rate is always within the actuator's tracking capability range, reducing mechanical shock and wear on the desuperheating water regulating valve, and extending the actuator's service life. By determining the lower bound of the width coefficient through Lipschitz constraints, the switching speed is ensured to match the actuator's capability, achieving a shift from post-event compensation to pre-event prevention.

[0069] Furthermore, the embodiments of the present invention can use a separate architecture of parameter design layer and real-time computing layer to place complex constraint satisfaction verification (e.g., as shown in equations (6), (7) and (8)) in the offline design stage. In the online operation stage, only exponential operation and weighted summation are involved, which reduces the computational burden and makes it easy to deploy and implement in existing DCS systems without requiring hardware modifications to the actuator.

[0070] The embodiments of this invention have cross-domain versatility and can be applied to other control systems that employ a multi-controller structure. Examples include steam temperature control in thermal power units, temperature control in chemical processes, and frequency control in power systems.

[0071] In a preferred embodiment of the present invention, the width coefficient determined above can be used. Within the feasible range, fine-tune online based on real-time control performance. This further enhances the system's adaptability to complex working conditions.

[0072] In embodiments of the present invention, a performance cost function J (e.g., the integral of the absolute value of the controlled variable error ITAE) can be defined to... To optimize variables. The adaptive update can be expressed in gradient descent form, as shown in the following equation:

[0073] in, For learning rate, To update the time index. After each update, you can... Project back to the feasible interval determined by equations (7) and (8) As shown in the following formula:

[0074] To ensure the updated Always meet the actuator rate limit and scope boundary constraints.

[0075] In an embodiment of the present invention, An analytical gradient exists, and numerical differencing is not required. Equation (1) is used to... Direct differentiation yields the analytical partial derivative of the applicability function with respect to the width coefficient, as shown in the following equation:

[0076] Through the chain rule The performance metrics can be adjusted accordingly. The gradient decomposes into four terms, where, J / u is calculated in real time from the error of the controlled variable. (Directly derived from equation (3)) By differentiating equation (2), we can obtain that The above equation is derived. The entire chain-like differentiation process only involves multiplication, addition, and exponentiation operations. The computational load is on the same order of magnitude as the original online calculation process (Equations (1) to (3)), making it suitable for implementation in existing DCS systems.

[0077] In terms of control effectiveness, when the system experiences rapid load changes, performance indicators deteriorate, and gradient descent automatically decreases. To accelerate controller switching response; when the system approaches steady state, gradient descent automatically increases. This reduces unnecessary controller switching actions and lowers the frequency of actuator movements. The aforementioned adaptive adjustment is used for fine-tuning within existing safety boundaries. The value of can be chosen without changing the core framework of the original technical solution.

[0078] This invention also provides a control device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the computer program to implement the above-described multi-controller switching control method.

[0079] This invention also provides a machine-readable storage medium storing instructions that cause a machine to execute the multi-controller switching control method described above.

[0080] It should be noted that the above-mentioned control device and machine-readable storage medium can implement the multi-controller switching control method provided in the above embodiments. For specific implementation methods, please refer to the description of the multi-controller switching control method in the above embodiments, which will not be repeated here.

[0081] This invention also provides a steam temperature control system, which may include multiple controllers, the aforementioned control devices, and actuators.

[0082] In a preferred embodiment of the present invention, each of the plurality of controllers sets a center point according to a preset operating condition. The center point is the value of the scheduling variable corresponding to the preset operating condition of each controller.

[0083] It should be noted that the steam temperature control system can implement the multi-controller switching control method provided in the above embodiments. For the specific implementation method, please refer to the description of the multi-controller switching control method in the above embodiments, which will not be repeated here.

[0084] The following text combines Figure 2 The embodiments of the present invention are explained in detail using a scenario of a 300MW thermal power unit participating in deep peak-shaving operation as an example. The rated main steam flow rate of this unit is, for example, [missing information]. The range of main steam flow variation under deep peak shaving conditions is, for example, as follows: to This corresponds to 30% to 100% of the rated load. The main steam temperature setpoint is, for example, [value missing]. Temperature control is achieved by adjusting the flow rate of the desuperheating water. The desuperheating water flow rate range is, for example, 0 to... (Corresponding to the stroke of the regulating valve) The temperature is controlled by a desuperheating water regulating valve, and the rate of change of the regulating valve stroke, for example, does not exceed [a certain percentage]. The corresponding upper limit of the rate of change of flow, for example .

[0085] Example steam temperature control system configuration includes, for example, a controller. controller and controller An equidistant arrangement strategy is adopted to cover the entire load range of deep peak shaving. Controller For example, in designs for low-load operating conditions, the center point ; controller For example, in medium-load condition design, the center point ; controller For example, in designs for high-load operating conditions, the center point The system, for example, uses a preset width factor. This value can be verified during the configuration phase using equation (7): the distance between the center points of adjacent controllers. Estimate the steady-state output difference between adjacent controllers ,but Further, based on equation (8), verify the upper bound constraint. Minimum distance between adjacent controllers. (For example, and (Center point spacing), take the applicability attenuation threshold. (That is, the applicability must decay to below 10% of the peak value at the midpoint to ensure a clear boundary between the two controller domains), then: Select value It is within a safe range and retains sufficient smoothness margin.

[0086] exist At that moment, the unit was operating under low-load steady-state conditions, and the main steam flow rate was... Main steam temperature Cooling water flow rate At this point, according to equation (1), the suitability of each controller is calculated: Controller applicability controller applicability controller applicability According to equation (2), after normalization, the weight distribution is as follows: At this point, the system is in a single-mode control state, and the controller... Main control output, controller and It is in standby mode. According to equation (3), the fused output... The desuperheating water regulating valve remains stable at the corresponding opening degree.

[0087] exist Time (based on load change rate) It took from 300 to 450. (seconds), main steam flow rate rises to (Located in the controller) and (The geometric midpoint of the line connecting the center points). At this point, according to equation (1), the suitability of each controller is calculated: ; .

[0088] According to equation (2), after normalization, the weight distribution is as follows: , , At this point, the system smoothly transitions from single-mode control to a dual-mode cooperative state, and the control strategy begins to balance low-load robustness with medium-load responsiveness. (Controller) The weight decreases from 1 to 0.5, and the controller... The weight increases from 0 to 0.5, and the weight transfer process is smooth and continuous without any jumps.

[0089] Calculate the derivative of the fitness function according to equation (5). Location, controller derivative of the fitness function controller derivative of the fitness function According to equation (4), the derivative of the weighting function can be calculated as follows: Its absolute value did not exceed the upper bound of the Lipschitz constant. According to equation (6) ), Upper bound of Lipschitz constant weight change rate It precisely reached the theoretical upper limit, further verifying the correctness of the embodiments of the present invention.

[0090] According to equation (11), the rate of change of the fused output includes both weight changes and controller output changes. In the switching transition region, weight changes dominate. Since the weight function satisfies the Lipschitz constraint, the rate of change of the weights is bounded; therefore, the rate of change of the fused output is also bounded. According to equation (10), the rate of change of the control quantity does not exceed the actuator rate limit. This ensures that the desuperheating water regulating valve can track control commands.

[0091] exist Time (from 300 to 600, change of 300, duration) (seconds), the main steam flow rate continued to rise to To reach the controller The center point. At this time, according to equation (1), the suitability of each controller is calculated: controller applicability controller applicability controller applicability According to equation (2), after normalization, the weight distribution is as follows: At this point, the system completes the transfer from the controller. To the controller The controller switches back to single-mode control mode. The main control output is activated. The entire switching process takes approximately 300 seconds (from...). arrive As the midpoint, from arrive (Completed), during which the weights migrate smoothly, the control quantity changes continuously, and there are no jumps.

[0092] exist Time (from 300 to 750, change of 450, duration) (seconds), the main steam flow rate continued to rise to At this point, according to equation (1), the suitability of each controller is calculated: Controller applicability controller applicability controller applicability After normalization according to equation (2), the weight distribution is as follows: At this point, the system re-enters the dual-modal cooperative state, and the controller... and controller Working in tandem, the control strategy balances medium-load responsiveness with high-load stability.

[0093] exist Time (from 300 to 900, change of 600, duration) (seconds), main steam flow rate rises to To reach the controller The center point. At this time, according to equation (1), the suitability of each controller is calculated: controller applicability controller applicability controller applicability According to equation (2), after normalization, the weight distribution is as follows: , , At this point, the system completes the transfer from the controller. To the controller The system switches to a high-load steady-state operation.

[0094] During the load increase process, the system underwent two controller switches: from controller Switch to controller Then from the controller Switch to controller During each switching process, the weights smoothly transition according to equation (2), and the fused output changes continuously according to equation (3). Due to the infinite differentiability of the Gaussian function, the weight function and its derivative are continuous throughout the switching process, ensuring that the rate of change of the control quantity does not jump. The system uses a preset width coefficient. (The system configuration phase has been verified to meet the actuator rate limit according to formula (7), ensuring that the switching speed matches the actuator capability.)

[0095] If the existing triangular membership function is used, it becomes non-differentiable at the switching boundary point, causing a sudden change in the derivative of the weighting function at the boundary point, resulting in a jump in the rate of change of the control variable. If a hard switching method is used, in... The control quantity may be from Jump to Jump variables reach Even under the ideal assumption of instantaneous switching (step transition), the rate of change of the control variable theoretically tends to infinity; if we consider that even the fastest switching in a real system requires a certain amount of time (e.g., 1 second), then the rate of change reaches... Exceeding the desuperheating water regulating valve ( The limitation of stroke rate causes the control valve to fail to track the command, resulting in switching disturbances. However, this embodiment of the invention employs Gaussian weighted fusion, in... Under these conditions, the weighted smooth transition feature time is approximately Seconds, the actual rate of change of the controlled quantity does not exceed ( ), satisfying the constraints of the implementing agency.

[0096] exist to During this period (1200 seconds of high-load steady-state operation), the unit operated stably under high-load conditions, with the main steam flow maintained at [value missing]. Nearby, the main steam temperature stabilized at the set value. Nearby. Controller The main control output is maintained at the desuperheating water flow rate. about.

[0097] exist At that moment, the power grid dispatch command instructed the generating unit to reduce its load, and the main steam flow began to decrease. The system, following the reverse sequence of the aforementioned load increase process, sequentially processed the load from the controller... Switch to controller Then from the controller Switch to controller . At time (1200 seconds of load reduction), the main steam flow rate drops to... The system enters / Dual-modal collaboration; in The moment, descending The system enters Single-mode; in The moment, descending The system enters / Dual-modal; in At that moment, the main steam flow rate dropped to The unit returned to low-load steady-state operation. (Controller) Regain control of the output, and restore the desuperheating water flow rate to [previous level]. The deep peak shaving cycle ended, and the system completed a full operating cycle from low load to high load and back to low load, lasting 6000 seconds (100 minutes). During this period, there were four controller switches, each of which was smooth and without disturbance.

[0098] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0099] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0100] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0101] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0102] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0103] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0104] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0105] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0106] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A multi-controller switching control method for a steam temperature system, characterized in that, The multi-controller switching control method includes: Obtain the values ​​of the scheduling variables used to characterize the current operating parameters of the target steam temperature system; Based on the obtained values ​​of the scheduling variables, and using the suitability function constructed based on the Gaussian function, the suitability of each controller of the target steam temperature system is determined; Using a preset weighting function, the applicability of each controller is normalized to obtain the weight of each controller. Based on the error signal of the target control quantity of the target steam temperature system, the output quantity of each controller is obtained; and Based on the output quantities and weights of each controller, a fused output quantity is obtained, and the fused output quantity is converted into a control command to switch the multiple controllers.

2. The multi-controller switching control method according to claim 1, characterized in that, Before determining the suitability of each controller in the target steam temperature system using the suitability function constructed based on the Gaussian function, the multi-controller switching control method further includes: An application function based on a Gaussian function is constructed using the scheduling variables, the center points of each controller, and the width coefficient, which is used to characterize the application function's shape parameter. The center point of each controller is the value of the scheduling variable corresponding to the preset operating condition of each controller.

3. The multi-controller switching control method according to claim 2, characterized in that, The controller is represented by the following formula. applicability function : in, Represents an exponential function. Represents the scheduling variable. Indicates controller The center point, This represents the width coefficient.

4. The multi-controller switching control method according to claim 2, characterized in that, The multi-controller switching control method further includes: Based on the Lipschitz constant constraint, the rate of change constraint of the actuator of the target steam temperature system is set; and Based on the rate of change constraint of the actuator of the target steam temperature system, the limit constraint of the width coefficient is set.

5. The multi-controller switching control method according to claim 4, characterized in that, The width coefficient is expressed by the following formula. Boundary constraints: in, This represents the maximum distance between the center points of adjacent controllers. This represents the maximum difference in steady-state output between adjacent controllers. This represents the rate of change constraint of the scheduling variable. This indicates the rate of change constraint of the actuator. This represents the minimum distance between the center points of adjacent controllers. This represents the applicability decay threshold.

6. The multi-controller switching control method according to claim 1, characterized in that, The multi-controller switching control method further includes: Determine whether the fused output quantity satisfies the rate of change constraint of the actuator of the target steam temperature system; If the fused output satisfies the rate of change constraint of the actuator of the target steam temperature system, then the step of converting the obtained fused output into control commands to switch control of multiple controllers is executed; and If the fused output does not meet the rate of change constraint of the actuator of the target steam temperature system, then the Lipschitz constant of the preset weighting function is constrained.

7. A control device, characterized in that, The control device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the multi-controller switching control method according to any one of claims 1-6.

8. A machine-readable storage medium, characterized in that, The machine-readable storage medium stores instructions that cause the machine to perform the multi-controller switching control method according to any one of claims 1-6.

9. A steam temperature control system, characterized in that, The steam temperature control system includes multiple controllers, the control device and actuator as described in claim 7.

10. The steam temperature control system according to claim 9, characterized in that, Each of the multiple controllers sets a center point according to preset operating conditions. The center point is the value of the scheduling variable corresponding to the preset operating conditions of each controller.

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