A full-load reheating flue gas damper control system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ANHUI HUADIAN SUZHOU POWER GENERATION
- Filing Date
- 2025-10-14
- Publication Date
- 2026-07-21
Smart Images
Figure CN224536375U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of reheat temperature control, specifically to a full-condition reheat flue gas damper control system. Background Technology
[0002] The reheat temperature control systems commonly used in current thermal power units, while possessing a certain regulatory capability under standard steady-state loads, gradually reveal their technical shortcomings when faced with dynamic disturbances and complex operating environments. They struggle to meet the comprehensive requirements of modern thermal power units for flexibility, response speed, and control precision. Traditional reheat temperature control systems primarily rely on the classic PID closed-loop control structure. This approach is based on assumptions such as system linearity, single-variable response, and predictable disturbances, to some extent ignoring the hysteresis, nonlinear behavior, and multivariable coupling relationships prevalent in reheat systems. Especially under conditions of variable load operation, start-stop switching, and rapid changes in reheat flue gas flow, the PID controller struggles to accurately and promptly capture the trend and magnitude of disturbances. Its output often exhibits hysteresis or over-regulation, leading to fluctuations in the high-temperature reheater outlet steam temperature. This not only affects system thermal efficiency but may also cause thermal fatigue damage to the equipment.
[0003] Furthermore, existing adjustment mechanisms and control systems are prone to getting caught in a cycle of frequent adjustments and error accumulation, which seriously affects the overall operational stability.
[0004] The current control system technology system has many bottlenecks in reheat system control, including insufficient ability to predict and compensate for disturbances, slow response of control structure, poor regulation quality and uneconomical operation of actuators. These defects have become key obstacles to the efficient operation of the unit and the improvement of deep adjustment adaptability.
[0005] Existing reheat system control systems exhibit significant shortcomings when facing complex operating conditions. Firstly, traditional PID control is slow to respond to load fluctuations, changes in furnace fuel composition, or other disturbances, making it difficult to provide precise temperature regulation. Reheater output often fluctuates significantly; if the control strategy lags or compensation is insufficient, steam temperature overshoot or undershoot can easily occur, affecting the unit's thermal economy and stable operation. Secondly, considering the current operating environment of thermal power plants, traditional control schemes rely heavily on fixed logic or single sensor feedback for disturbance identification and compensation, lacking system coordination and timely response to multiple influencing factors. This results in the system performing reasonably well under full-load steady-state conditions, but once it enters the load variation or peak-shaving phase, it falls into a state of frequent malfunctions and instability. Utility Model Content
[0006] To address the shortcomings of existing technologies, this invention proposes a full-condition reheat flue gas damper control system, which has stronger predictive capabilities, better dynamic response characteristics, and a novel control system that is friendly to actuators, adapting to the complex operating environment and stringent control requirements of thermal power units.
[0007] This utility model proposes a full-condition reheat flue gas damper control system, including a power supply module, a prediction module, a bus communication module, a microprocessor module, and a drive module; The power module is connected to the bus communication module, the bus communication module is connected to the prediction module, and the output of the bus communication module is connected to the microprocessor module and the driver module; the microprocessor module is connected to the driver module. The power supply module is equipped with a voltage conversion circuit, which is connected to the input terminal of the bus communication module; the microprocessor module is equipped with a microprocessor, which is bidirectionally connected to the bus communication module; the drive module is equipped with a drive circuit and a relay, the drive circuit is connected to the output terminal of the microprocessor and the input terminal of the relay, and the output terminal of the relay is connected to a baffle.
[0008] In some embodiments, the prediction module includes a prediction controller, a load baseline feedforward module, a low-temperature reheater feedforward compensation module, a high-temperature reheater wall temperature protection module, and a control signal superposition and weighting module.
[0009] In some embodiments, the predictive controller includes a feedback adjustment interface and a filter circuit consisting of multiple series resistors and parallel capacitors. The output of the filter circuit is connected to the input of the control signal superposition and weighting module; The control signal superposition and weighting module output is connected to the feedback adjustment interface.
[0010] In some embodiments, the control signal superposition and weighting module has multiple input ports, which are respectively connected to the output of the load baseline feedforward module, the output of the low-temperature reheater feedforward compensation module, and the output of the high-temperature reheater wall temperature protection module.
[0011] In some embodiments, the input of the load baseline feedforward module is connected to a sensor circuit; The load baseline feedforward module includes a baseline calculation circuit, which is a voltage divider network composed of an operational amplifier and several resistors; The output of the baseline calculation circuit is connected to the input of the signal superposition and weighting module.
[0012] In some embodiments, the low-temperature reheater feedforward compensation module is provided with a temperature signal input interface, which is connected to the temperature sensor of the low-temperature reheater. The low-temperature reheater feedforward compensation module includes a compensation calculation circuit, which includes a proportional-integral-differential arithmetic unit circuit built with an operational amplifier. The output of the proportional-integral-differential (PI-DI) arithmetic unit circuit is connected to the input of the signal superposition and weighting module.
[0013] In some embodiments, the high-temperature reheater wall temperature protection module is connected to the wall temperature sensor of the high-temperature reheater through a wall temperature signal input port; The high-temperature reheater wall temperature protection module includes a protection logic judgment circuit, which includes a reference voltage setting circuit consisting of a comparator and multiple resistors. The output of the reference voltage setting circuit is connected to the input of the signal superposition and weighting module.
[0014] In some embodiments, the control signal superposition and weighting module includes a signal conditioning submodule, an adder, and a weighting coefficient setting circuit. The input terminal of the adder is connected to the output terminal of the weighting coefficient setting circuit, and the output terminal of the adder is connected to the input terminal of the signal conditioning submodule. The signal conditioning submodule includes a filter capacitor circuit and a limiting circuit, which are connected together to the prediction controller.
[0015] In some embodiments, the power module includes a VPS input circuit, a Vcc output circuit, and a Vdd output circuit; The VPS input circuit is connected to the input terminal of the power module, the power module is connected to the bus communication module through the Vcc output circuit, and the power module is connected to the interface indicator module through the Vdd output circuit.
[0016] In some embodiments, the bus communication module is bidirectionally connected to the prediction module via a Vbus circuit; The interface indicator module is interactively connected to the microprocessor via I / O circuitry; The relay is connected to the baffle via a VPS circuit.
[0017] The beneficial effects of this utility model are as follows: This utility model includes a power supply module, a prediction module, a bus communication module, a microprocessor module, and a driver module. The power supply module is connected to the bus communication module, the bus communication module is connected to the prediction module, and the output terminal of the bus communication module is connected to the microprocessor module and the driver module. The microprocessor module is connected to the driver module. The power supply module has a voltage conversion circuit, which is connected to the input terminal of the bus communication module. The microprocessor module has a microprocessor, which is bidirectionally connected to the bus communication module. The driver module has a driver circuit and a relay, the driver circuit is connected to the output terminal of the microprocessor and the input terminal of the relay, and the output terminal of the relay is connected to a baffle.
[0018] This system compensates for typical disturbances in advance by using multi-channel feedforward modules covering variable load, low-temperature reheater outlet temperature, and high-temperature reheater wall temperature. It also integrates the multi-channel feedforward output with the GPC output, thereby achieving robustness and dynamic adaptability of the overall control output and significantly improving the temperature control quality and system stability. Attached Figure Description
[0019] To better understand this invention, reference can be made to the embodiments shown in the following figures. Components in the figures are not necessarily drawn to scale, and related elements may be omitted, or in some cases the scale may have been enlarged to emphasize and clearly illustrate the novel features described herein. Additionally, as is known in the art, system components may be arranged differently. Furthermore, in the figures, the same reference numerals denote corresponding parts throughout several views.
[0020] Figure 1 A reference schematic diagram of the damper execution drive unit of a full-condition reheat flue gas damper control system of this utility model is shown.
[0021] Figure 2 A reference schematic diagram of the damper data transmission unit of a full-condition reheat flue gas damper control system according to this utility model is shown.
[0022] Figure 3 A reference schematic diagram of a full-condition reheat flue gas damper control system according to this utility model is shown. Detailed Implementation
[0023] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the present invention. Accordingly, all such modifications should be included within the scope of this invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the present invention.
[0024] This utility model proposes a full-condition reheat flue gas damper control system. Please refer to [link / reference]. Figure 1 and Figure 2 It includes a power module, a prediction module, a bus communication module, a microprocessor module, and a driver module; The power module is connected to the bus communication module, the bus communication module is connected to the prediction module, and the output of the bus communication module is connected to the microprocessor module and the driver module; the microprocessor module is connected to the driver module. The power supply module is equipped with a voltage conversion circuit, which is connected to the input terminal of the bus communication module; the microprocessor module is equipped with a microprocessor, which is bidirectionally connected to the bus communication module; the drive module is equipped with a drive circuit and a relay, the drive circuit is connected to the output terminal of the microprocessor and the input terminal of the relay, and the output terminal of the relay is connected to a baffle.
[0025] Figure 1 Each module in the system has a clearly defined and independent function. The power supply module focuses on power conversion and supply, the bus communication module is responsible for data transmission, and the microprocessor performs core control. The power supply module provides appropriate voltages to different modules, ensuring that each module operates in a stable power environment, reducing system failures caused by power supply issues, and improving system reliability. The bus communication module enables information exchange between the system and external systems, allowing the system to receive external commands and adjust according to actual conditions. The microprocessor, as the control center, precisely controls the opening of the reheat flue gas damper through the drive module, meeting control requirements under all operating conditions. The interface indicator module intuitively displays the system's operating status through LEDs, allowing operators to understand the system's operation in a timely manner and quickly identify and take appropriate measures when system failures occur, improving the system's operability and maintainability. The relays and drive circuits in the drive module provide sufficient drive capability, ensuring effective control of external equipment such as the reheat flue gas damper, guaranteeing the system's performance in practical applications.
[0026] Figure 2The process involves data transmission and reception, with data exchange via a data bus and multiple control signal lines connecting various modules. When data needs to be transmitted, the transmission interrupt unit generates an interrupt signal XINT to notify the system of a transmission task. It acts as the trigger source for the transmission process, initiating the entire transmission operation.
[0027] The DXR (Data Transmit Register) is used to temporarily store data to be transmitted. When a transmit interrupt is triggered, data is placed in the DXR in preparation for transmission.
[0028] The XSR (Transmit Shift Register) acquires data from the DXR and shifts the data bit-by-bit according to the communication protocol format. It serves as a buffer and format conversion stage for the actual data transmission.
[0029] Transmit control circuit: Based on the system's control logic and state, it generates the control signal XWDONE (transmission complete signal) to indicate whether the data transmission operation is complete. It may also be responsible for coordinating timing and other control functions during the transmission process.
[0030] When the receive interrupt unit receives data, it generates an interrupt signal RINT to notify the system that new data has arrived. It is the trigger signal for the receive process.
[0031] The DRR (Data Receive Register) is used to store data received from external sources. After the data is processed through the receiving process, it is ultimately stored in the DRR for subsequent use by the system.
[0032] The Receive Buffer Register (RBR) acts as a buffer during data reception. It first receives data bits transmitted from the outside, and then transmits the complete data to the Receive Buffer Register (RSR).
[0033] The RSR (Receive Shift Register) reassembles the bit-by-bit data received through the data bus into complete data units according to the protocol format and transmits them to the RBR.
[0034] Receive control circuit: Generates the control signal RWDONE, i.e., the receive completion signal, used to indicate whether the data reception operation is complete. It is responsible for managing various control logics and timing during the reception process.
[0035] The data bus is the data transmission channel between the transmitting and receiving parts, responsible for transmitting data between registers such as DXR, XSR, RSR, RBR, and DRR.
[0036] Control signal lines are used to coordinate the operations of the sending and receiving parties, ensuring the synchronous and orderly transmission of data.
[0037] In some embodiments, the prediction module includes a prediction controller, a load baseline feedforward module, a low-temperature reheater feedforward compensation module, a high-temperature reheater wall temperature protection module, and a control signal superposition and weighting module.
[0038] The predictive controller connects to the load baseline feedforward module, enabling timely acquisition of load baseline information. This allows for predictions based on a more comprehensive understanding of operating conditions, improving the accuracy of predicting reheat flue gas damper opening adjustment commands. Connecting to the low-temperature reheater feedforward compensation module incorporates real-time temperature compensation information from the low-temperature reheater, ensuring the prediction fully considers its operating status and preventing prediction deviations due to changes in reheater operating conditions. Connecting to the high-temperature reheater wall temperature protection module allows for the receipt of wall temperature protection signals. When the high-temperature reheater wall temperature is abnormal, this signal allows for timely adjustments to the prediction results, preventing equipment damage due to overheating and ensuring system safety.
[0039] The control signal superposition and weighting module acts as a central hub, integrating the signals from the predictive controller, feedforward module, and protection module. Through appropriate weighting, it synthesizes the influence of various factors on the baffle opening.
[0040] In some embodiments, the predictive controller includes a feedback adjustment interface and a filter circuit consisting of multiple series resistors and parallel capacitors. The output of the filter circuit is connected to the input of the control signal superposition and weighting module; The control signal superposition and weighting module output is connected to the feedback adjustment interface.
[0041] The feedback adjustment interface of the predictive controller is connected to a filter circuit consisting of multiple series resistors and parallel capacitors. This filter circuit performs preliminary processing on the signal input to the predictive controller. The filter circuit composed of series resistors and parallel capacitors can effectively filter out high-frequency noise and interference components in the signal, making the signal entering the predictive controller purer and more stable. This provides high-quality input data for subsequent predictive control algorithms, helping to improve the accuracy of predictions.
[0042] The output of the filter circuit is connected to the input of the control signal superposition and weighting module. This allows the filtered signal to enter the module smoothly, where it is superimposed and weighted with other control signals to generate a more reasonable reheat flue gas damper opening adjustment command.
[0043] The output of the control signal superposition and weighting module is then connected back to the feedback adjustment interface of the predictive controller, forming a closed-loop feedback circuit. Through this circuit, the integrated adjustment command information can be fed back to the predictive controller, enabling it to adjust and optimize the predictive control algorithm in real time based on the actual output adjustment commands. This further enhances the system's adaptability to different operating conditions and improves the control performance and stability of the entire reheat flue gas damper control system.
[0044] In some embodiments, the control signal superposition and weighting module has multiple input ports, which are respectively connected to the output of the load baseline feedforward module, the output of the low-temperature reheater feedforward compensation module, and the output of the high-temperature reheater wall temperature protection module.
[0045] The load baseline feedforward module, the low-temperature reheater feedforward compensation module, and the high-temperature reheater wall temperature protection module provide control signals from different perspectives. Multiple input ports allow these signals to converge simultaneously into the control signal superposition and weighting module, providing a comprehensive data foundation for generating integrated control commands. The signals from different modules reflect the system's operating status and requirements in different aspects. Through superposition and weighting processing, factors such as load changes, low-temperature reheater compensation, and high-temperature reheater wall temperature protection can be comprehensively considered, making the final generated reheat flue gas damper opening adjustment command more consistent with actual operating conditions and improving control accuracy.
[0046] In some embodiments, the input of the load baseline feedforward module is connected to a sensor circuit; The load baseline feedforward module includes a baseline calculation circuit, which is a voltage divider network composed of an operational amplifier and several resistors; The output of the baseline calculation circuit is connected to the input of the signal superposition and weighting module.
[0047] The load baseline feedforward module is connected to the sensor circuit at its input end, which can directly acquire the raw signal reflecting the load condition, ensuring the timeliness and originality of the data source. The baseline calculation circuit consists of an operational amplifier and a voltage divider network composed of several resistors. The operational amplifier can amplify and buffer the input signal to enhance the signal's driving capability and stability. The voltage divider network can adjust the signal according to preset rules to calculate the load baseline feedforward signal.
[0048] In some embodiments, the low-temperature reheater feedforward compensation module is provided with a temperature signal input interface, which is connected to the temperature sensor of the low-temperature reheater. The low-temperature reheater feedforward compensation module includes a compensation calculation circuit, which includes a proportional-integral-differential arithmetic unit circuit built with an operational amplifier. The output of the proportional-integral-differential (PI-DI) arithmetic unit circuit is connected to the input of the signal superposition and weighting module.
[0049] The temperature signal input interface of the low-temperature reheater feedforward compensation module is directly connected to the temperature sensor of the low-temperature reheater, avoiding data delay or distortion caused by too many intermediate links, and enabling the module to quickly sense the temperature changes of the low-temperature reheater.
[0050] The compensation calculation circuit employs a proportional-integral-derivative (PID) arithmetic unit circuit built with operational amplifiers. Its input is connected to the temperature signal input interface, enabling rapid and accurate processing of the temperature signal. The PID arithmetic unit calculates a suitable compensation signal based on the temperature deviation, following the rules of proportional, integral, and derivative operations. The output of the PID arithmetic unit circuit is connected to the input of the signal superposition and weighting module, achieving feedforward compensation control, improving the system's response to temperature changes in the cryogenic reheater, and ensuring system operational stability.
[0051] In some embodiments, the high-temperature reheater wall temperature protection module is connected to the wall temperature sensor of the high-temperature reheater through a wall temperature signal input port; The high-temperature reheater wall temperature protection module includes a protection logic judgment circuit, which includes a reference voltage setting circuit consisting of a comparator and multiple resistors. The output of the reference voltage setting circuit is connected to the input of the signal superposition and weighting module.
[0052] The high-temperature reheater wall temperature protection module connects directly to the wall temperature sensor of the high-temperature reheater via the wall temperature signal input port, enabling it to quickly and accurately acquire real-time wall temperature data. This effectively avoids signal attenuation and interference during transmission, ensuring the authenticity and timeliness of the wall temperature information.
[0053] In the protection logic judgment circuit, a reference voltage setting circuit, consisting of a comparator and multiple resistors, is connected to the wall temperature signal input port. This circuit allows for rapid comparison and judgment between the input wall temperature signal and the reference voltage of the preset wall temperature protection threshold. The output of the reference voltage setting circuit is connected to the input of the signal superposition and weighting module, ensuring that the judgment result is promptly incorporated into the generation of comprehensive control commands. Once the wall temperature exceeds the threshold, the protection signal quickly influences the reheat flue gas damper opening adjustment command, promptly adjusting the damper opening to protect the high-temperature reheater, preventing equipment damage due to excessively high wall temperatures, and ensuring the safe and stable operation of the entire system.
[0054] In some embodiments, the control signal superposition and weighting module includes a signal conditioning submodule, an adder, and a weighting coefficient setting circuit. The input terminal of the adder is connected to the output terminal of the weighting coefficient setting circuit, and the output terminal of the adder is connected to the input terminal of the signal conditioning submodule. The signal conditioning submodule includes a filter capacitor circuit and a limiting circuit, which are connected together to the prediction controller.
[0055] The input of the adder is connected to the output of the weighting coefficient setting circuit, which can superimpose the control signals after the weighting coefficients have been adjusted.
[0056] The adder output is connected to the signal conditioning submodule input, and the superimposed signal can immediately enter the signal conditioning submodule for processing. The filter capacitor circuit can filter out high-frequency noise in the signal, making the signal smoother and more stable; the limiting circuit can limit the amplitude range of the signal to prevent the signal from being too large and causing damage to subsequent circuits.
[0057] In some embodiments, the power module includes a VPS input circuit, a Vcc output circuit, and a Vdd output circuit; The VPS input circuit is connected to the input terminal of the power module, the power module is connected to the bus communication module through the Vcc output circuit, and the power module is connected to the interface indicator module through the Vdd output circuit.
[0058] This reduces communication errors or interruptions caused by power fluctuations, ensuring the stability and accuracy of data transmission between the system and external systems.
[0059] In some embodiments, the bus communication module is bidirectionally connected to the prediction module via a Vbus circuit; The interface indicator module is interactively connected to the microprocessor via I / O circuitry; The relay is connected to the baffle via a VPS circuit.
[0060] The bus communication module achieves real-time information exchange through bidirectional connection with the prediction module via the Vbus circuit. The interface indicator module interacts with the microprocessor through the IO circuit, enabling the microprocessor to accurately control the working state of the interface indicator module. The interface indicator module feeds back its own state to the microprocessor.
[0061] The relay is connected to the baffle via the VPS circuit, ensuring that the control signal can be transmitted to the baffle stably and reliably, achieving precise control of the baffle opening. This reduces intermediate links in signal transmission, lowers the risk of signal interference and loss, and guarantees the effectiveness and stability of baffle control.
[0062] In some embodiments, this utility model provides a full-condition reheat flue gas damper control system. Please refer to [link / reference]. Figure 3 ,include: A data acquisition and preprocessing unit 100 is configured to generate preprocessed parameters. A dynamic identification modeling unit 200, the input of which is connected to the output of the data acquisition and preprocessing unit, is configured to generate the response characteristics of reheat temperature as a function of load change and damper opening. A generalized predictive control unit 300, the input of which is connected to the output of the dynamic identification modeling unit, is configured to receive the response characteristics of the reheat temperature with load change and damper opening, and generate an adjustment command for the reheat flue gas damper opening. An actuator drive unit 400, the input of which is connected to the output of the generalized predictive control unit, is configured to receive the adjustment command for the opening of the reheat flue gas damper and control the electric or pneumatic actuator of the flue gas damper.
[0063] In this embodiment, the prediction module is defined as a generalized prediction control unit, and the driving module is an actuator driving unit.
[0064] This utility model belongs to the field of thermal power generation technology, and specifically discloses a full-condition reheat flue gas damper control system based on generalized predictive control and intelligent feedforward, which is suitable for the precise control of high-temperature reheater steam temperature in the reheater system of supercritical units.
[0065] This system introduces Generalized Predictive Control (GPC) as its core control structure. Addressing issues such as multivariable coupling, time-delay characteristics, and non-compliance with linear assumptions in reheat systems, it constructs a mathematical model to predict future system behavior, thereby achieving forward-looking and precise temperature control and effectively compensating for the response lag and control blind spots of existing methods. By constructing a multi-channel feedforward model covering variable load, low-temperature reheater outlet temperature, and high-temperature reheater wall temperature, typical disturbances are compensated for in advance. Furthermore, the multi-channel feedforward output is superimposed and fused with the GPC output, achieving robustness and dynamic adaptability of the overall control output, significantly improving temperature control quality and system stability.
[0066] The data acquisition unit is used to collect multiple operating parameters from the unit site, including at least the current unit load, the low-temperature reheater outlet temperature, the high-temperature reheater furnace-side gas temperature, the high-temperature reheater outlet wall temperature, and the current reheat flue gas damper opening. The data is transmitted in real-time to the data preprocessing module via a communication module. This module incorporates industrial noise filtering algorithms and data anomaly removal logic to ensure the accuracy of subsequent modeling and the stability of control strategy execution.
[0067] This unit is used to construct the dynamic response model of the system. A neural network algorithm or recursive least squares algorithm is employed to establish a transfer function model between the unit's input and output based on the collected parameters. The model input includes the five operating parameters mentioned above, and the output is the outlet temperature of the high-temperature reheater on the turbine side. The constructed model can describe the response characteristics of the reheat temperature with load changes and damper opening, serving as the core model for predictive controllers.
[0068] The control signal is output from the weighted module and then transmitted to the actuator drive unit, which controls the electric or pneumatic actuator of the flue gas damper. The actuator responds to the control command to achieve precise angle adjustment. This unit is equipped with a position feedback system that can detect the current position of the damper in real time, ensuring closed-loop control of the actuator's operation.
[0069] The generalized prediction control unit includes a prediction model module; The prediction model module includes a prediction controller, a load baseline feedforward module, a low-temperature reheater feedforward compensation module, a high-temperature reheater wall temperature protection module, and a control signal superposition and weighting module.
[0070] The generalized predictive control unit comprises three parts: a predictive model module, a rolling optimization module, and a feedback correction module. Its control objective is to minimize the deviation between the high-temperature reheater outlet temperature and the setpoint, while suppressing the drastic changes in the control input. This unit constructs a dynamic predictive model based on the upper-level modeling results, and outputs control commands under the optimization function by setting the prediction time domain and control time domain windows.
[0071] High-temperature reheaters exhibit significant thermal delay. Predictive models can anticipate future temperature trends, avoiding overshoot or oscillation caused by lag in traditional feedback control. By setting a prediction time domain, the optimization objective can cover temperature deviations at multiple future points, achieving a smoother control trajectory.
[0072] At each sampling time, the rolling optimization module solves the finite-time optimization problem based on the prediction model and the current state to generate the optimal fuel flow adjustment.
[0073] The feedback correction module utilizes the deviation between real-time temperature measurements and predicted values to correct the prediction model through a feedback correction mechanism, compensating for unmodeled dynamics and external disturbances. This feedback mechanism forms a closed-loop control, ensuring stable system operation even with disturbances or model errors, thus avoiding the divergence risk of open-loop predictive control. The predictive controller is configured to receive the response characteristics of the reheat temperature as a function of load and damper opening, and generate a predictive control output signal.
[0074] The controller output is an adjustment command for the opening of the reheat flue gas damper, which has adaptive capability and can dynamically respond to load changes.
[0075] The controller dynamically adjusts the predictive model parameters by monitoring load signals in real time, ensuring that the control strategy matches the current operating conditions. Traditional PID control may fail to tune parameters due to load changes. By dynamically adjusting the optimization target, the controller ensures that the damper action is neither too aggressive nor too delayed.
[0076] The load baseline feedforward module is configured to receive historical load operation data collected by the data acquisition and preprocessing unit, establish a baseline mapping curve of load-baffle opening, and generate a corresponding load baseline value signal.
[0077] This module establishes a baseline mapping curve between load and damper opening based on historical load operation data, uses a clustering algorithm to divide typical load operation intervals, and generates continuously callable baseline curves through an interpolation function. When the load changes, this module provides a feedforward command for the corresponding damper opening as a reference for the predictive controller's control quantity, improving the overall control system's response speed and accuracy to load changes.
[0078] This solution introduces a load-cluster-based feedforward control baseline to replace the traditional setpoint start-stop logic. The difference lies in that this solution establishes the load-damper opening curve through clustering of historical operating data, rather than using fixed damper settings or manual adjustments. Compared to existing fixed-point damper control, it offers more precise response and significantly improves reheat steam temperature stability under varying load conditions.
[0079] By clustering historical data, including load, damper opening, temperature deviation, and flue gas temperature, different operating condition clusters are automatically identified, and corresponding damper opening curves are generated.
[0080] In some embodiments, please refer to Figure 3 The input terminal of the low-temperature reheater feedforward compensation module is connected to the outlet of the low-temperature reheater and is configured to perform delay correction based on the temperature change trend of the low-temperature reheater outlet to generate a low-temperature outlet feedforward signal.
[0081] This module is used to adjust the opening of the reheat flue gas damper in advance based on the changing trend of the cryogenic reheater outlet temperature. The module contains a feedforward separator that, by judging the rate and direction of temperature change, adds delay correction logic after the compensation output to ensure that the feedforward command is withdrawn in a timely manner after the cryogenic reheater outlet temperature stabilizes, avoiding system over-response. Its output signal is processed and superimposed on the output signal of the predictive controller.
[0082] A dynamic trend feedforward and separation recovery mechanism for the outlet temperature of the low-temperature reheater is added. The difference lies in that this scheme introduces a temperature change rate function and superimposes delayed withdrawal logic, rather than directly using the low-temperature setpoint for constant compensation. This solves the problem of lag and over-adjustment in low-temperature disturbance feedback and improves the disturbance resistance and accuracy of high-temperature reheat temperature control.
[0083] By calculating the temperature change rate, rising or falling temperature trends can be identified in advance, and the compensation strategy can be dynamically adjusted. If the temperature change rate exceeds the threshold, it indicates that the flue gas temperature is excessive. In this case, the compensation amount should be reduced or the compensation should be withdrawn in advance to avoid overshoot. If the temperature change rate is below the threshold, it indicates that the flue gas temperature is insufficient. In this case, the compensation amount should be increased or the compensation time should be extended to prevent undershoot.
[0084] Introducing a compensation withdrawal delay time prevents frequent compensation switching due to temperature fluctuations.
[0085] The input terminal of the high-temperature reheater wall temperature protection module is connected to the high-temperature reheater and is configured to predict the wall temperature of the high-temperature reheater and generate a corresponding wall temperature deviation protection signal based on the predicted wall temperature and heating rate.
[0086] This module includes a wall temperature prediction unit and deviation judgment logic. The wall temperature prediction unit uses a thermal inertia model to predict the wall temperature in real time two minutes later. If the predicted value exceeds the set upper limit temperature and the heating rate exceeds the protection threshold, emergency control logic is triggered. This prioritizes modifying the damper opening command to immediately reduce the flue gas flow, preventing the wall temperature from exceeding the limit and ensuring the structural safety of the equipment. This module has the highest priority command channel, and control signals can forcibly override ordinary control commands.
[0087] The wall temperature prediction and deviation protection logic can forcibly override control commands to achieve proactive safety. The difference lies in that this solution uses a wall temperature rise trend prediction and difference triggering strategy to actively modify control commands, rather than relying on traditional alarm interlock protection. This improves the response speed to abnormal wall temperatures, achieves feedforward protection for critical heat exchanger structures, and enhances equipment safety margins.
[0088] By calculating the wall temperature change rate and fitting a trend curve using historical data, future wall temperature values can be predicted. A dynamic prediction model is constructed by correlating the wall temperature change rate with parameters such as load change rate, flue gas temperature, and steam flow rate.
[0089] Increased load leads to higher flue gas temperature. The prediction model increases the weight of overheat risk and triggers regulation 20 seconds in advance.
[0090] A decrease in load leads to a reduction in steam flow, which reduces the sensitivity of the wall temperature change rate. The prediction model extends the prediction time window to avoid false triggering.
[0091] The input of the control signal superposition and weighting module is connected to the output of the predictive controller, the load baseline feedforward module, the low-temperature reheater feedforward compensation module, and the high-temperature reheater wall temperature protection module. It is configured to weight and fuse the predictive control output signal, the low-temperature outlet feedforward signal, the wall temperature deviation protection signal, and the load baseline value signal to obtain the adjustment command for the opening of the reheat flue gas damper.
[0092] The system includes a control signal superposition and weighting unit to fuse multiple control signals output from the aforementioned control modules (including predictive control output, cryogenic outlet feedforward, wall temperature deviation protection, and load baseline value). Each signal is multiplied by its corresponding adjustable weighting coefficient and then aggregated into the final execution command. Users can manually or adaptively set the weighting values according to operating conditions to meet the control performance requirements at different operating stages. Its mathematical form is: in, To determine the final output reheat flue gas damper opening, Output the reheat flue gas damper opening to the GPC controller. The feedforward opening is based on the outlet temperature of the cryogenic reheater. To protect the outlet wall temperature from deviations during high-temperature reheating, the baffle opening is adjusted accordingly. For baseline feedforward based on unit load, to The weighting coefficients are adjustable.
[0093] The predictive control output signal predicts future wall temperature change trends based on historical data and real-time operating conditions (such as load and flue gas temperature), and generates adjustment commands in advance.
[0094] The low-temperature outlet feedforward signal quickly adjusts the damper opening based on the temperature change at the low-temperature reheater outlet to compensate for the heat transfer delay on the flue gas side.
[0095] The wall temperature deviation protection signal forces an increase in the adjustment range when the wall temperature approaches or exceeds the threshold, ensuring safety.
[0096] The load baseline value signal dynamically adjusts the weight of each signal according to the current load level. The weight of the predictive control signal is increased when the load is high, and the weight of the wall temperature deviation signal is increased when the load is low.
[0097] If only the wall temperature deviation protection signal is used, the protection threshold may not match the actual risk due to changes in operating conditions. Predictive control signals and low-temperature outlet feedforward signals are used to suppress the rising trend of wall temperature in advance, keeping the wall temperature below the safe threshold. When the wall temperature deviation protection signal is triggered, the damper opening is adjusted according to the over-temperature amplitude, while simultaneously limiting the rate of steam temperature decrease to avoid thermal stress shock. The protection threshold is dynamically adjusted based on the load baseline value to match the metal's temperature resistance under different operating conditions.
[0098] The feedforward compensation module of the low-temperature reheater is equipped with a feedforward separator, which is configured to determine the rate and direction of temperature change.
[0099] Conventional feedforward signals only reflect changes in operating conditions but cannot distinguish dynamic differences in temperature changes under the same operating conditions. The priority of feedforward signals is dynamically adjusted based on the rate and direction of temperature change. When the temperature rises rapidly, the temperature feedforward signal is given the highest priority, and adjustment requests from pressure and flow feedforward signals are blocked. When the temperature stabilizes, weighted fusion control of multivariable feedforward signals is restored.
[0100] The high-temperature reheater wall temperature protection module is configured to generate a wall temperature deviation protection signal that prioritizes modifying the baffle opening command when the predicted wall temperature exceeds the preset upper limit temperature and the heating rate exceeds the preset protection threshold.
[0101] By directly connecting the wall temperature deviation protection signal to the high priority of the baffle actuator, the conventional control logic is bypassed, ensuring that the command is executed quickly.
[0102] The control signal superposition and weighting module is configured for manually or adaptively setting weights.
[0103] The adaptive algorithm continuously updates the system model parameters using real-time data and dynamically adjusts the weights to match model changes.
[0104] The above embodiments are possible examples of implementation of this utility model, and are provided only to enable those skilled in the art to clearly understand the principles of this utility model. Those skilled in the art should understand that the above discussion of any embodiment is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of this utility model is limited to these examples. Under the overall concept of this utility model, the technical features of the above embodiments or different embodiments can also be combined with each other, resulting in many other variations of different aspects of the embodiments of this utility model as described above. For the sake of brevity, these variations are not provided in the specific embodiments. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this utility model should be included within the protection scope claimed by this utility model.
Claims
1. A full-condition reheat flue gas damper control system, characterized in that, It includes a power supply module, a prediction module, a bus communication module, a microprocessor module, and a driver module; The power supply module is connected to the bus communication module, which in turn is connected to the prediction module. The output of the bus communication module is connected to the microprocessor module and the driver module. The microprocessor module is connected to the driver module. The prediction module includes a prediction controller, a load baseline feedforward module, a low-temperature reheater feedforward compensation module, a high-temperature reheater wall temperature protection module, and a control signal superposition and weighting module. The prediction controller includes a feedback adjustment interface and a filter circuit composed of multiple series resistors and parallel capacitors. The load baseline feedforward module includes a baseline calculation circuit, which is a voltage divider network composed of an operational amplifier and several resistors. The low-temperature reheater feedforward compensation module includes a compensation calculation circuit, which includes a proportional-integral-differential (PI-DI) arithmetic unit circuit built with an operational amplifier. The high-temperature reheater wall temperature protection module includes a protection logic judgment circuit, which includes a reference voltage setting circuit composed of a comparator and multiple resistors. The control signal superposition and weighting module includes a signal conditioning submodule, an adder, and a weighting coefficient setting circuit. The power supply module is equipped with a voltage conversion circuit, which is connected to the input terminal of the bus communication module; the microprocessor module is equipped with a microprocessor, which is bidirectionally connected to the bus communication module; the drive module is equipped with a drive circuit and a relay, the drive circuit is connected to the output terminal of the microprocessor and the input terminal of the relay, and the output terminal of the relay is connected to an existing baffle.
2. The full-condition reheat flue gas damper control system according to claim 1, characterized in that, The output of the filter circuit is connected to the input of the control signal superposition and weighting module; The control signal superposition and weighting module output is connected to the feedback adjustment interface.
3. The full-condition reheat flue gas damper control system according to claim 2, characterized in that, The control signal superposition and weighting module has multiple input ports, which are respectively connected to the output of the load baseline feedforward module, the output of the low temperature reheater feedforward compensation module, and the output of the high temperature reheater wall temperature protection module.
4. The full-condition reheat flue gas damper control system according to claim 3, characterized in that, The input terminal of the load baseline feedforward module is connected to the sensor circuit; The output of the baseline calculation circuit is connected to the input of the signal superposition and weighting module.
5. The full-condition reheat flue gas damper control system according to claim 3, characterized in that, The low-temperature reheater feedforward compensation module is equipped with a temperature signal input interface, which is connected to the temperature sensor of the low-temperature reheater. The output of the proportional-integral-differential (PI-DI) arithmetic unit circuit is connected to the input of the signal superposition and weighting module.
6. The full-condition reheat flue gas damper control system according to claim 3, characterized in that, The high-temperature reheater wall temperature protection module is connected to the high-temperature reheater wall temperature sensor through the wall temperature signal input port. The output of the reference voltage setting circuit is connected to the input of the signal superposition and weighting module.
7. The full-condition reheat flue gas damper control system according to claim 1, characterized in that, The input terminal of the adder is connected to the output terminal of the weighting coefficient setting circuit, and the output terminal of the adder is connected to the input terminal of the signal conditioning submodule. The signal conditioning submodule includes a filter capacitor circuit and a limiting circuit, which are connected together to the prediction controller.
8. The full-condition reheat flue gas damper control system according to claim 1, characterized in that, The power module is equipped with a VPS input circuit, a Vcc output circuit, and a Vdd output circuit. The VPS input circuit is connected to the input terminal of the power module, the power module is connected to the bus communication module through the Vcc output circuit, and the power module is connected to the interface indicator module through the Vdd output circuit.
9. The full-condition reheat flue gas damper control system according to claim 8, characterized in that, The bus communication module is bidirectionally connected to the prediction module via a Vbus circuit. The interface indicator module is interactively connected to the microprocessor via I / O circuitry; The relay is connected to the baffle via a VPS circuit.