A multi-parameter adaptive control device for power boiler feedwater system and a feedwater system

Abstract

A kind of power boiler feedwater system multi-parameter adaptive control device and feedwater system.It relates to the technical field of power boiler control, in view of the limited dimension of existing boiler feedwater control parameters, the insufficient adaptability of fixed parameter control and the dispersed problem of acquisition control execution structure, the following scheme is proposed: set up multi-parameter sensor module, embedded intelligent controller module and actuator control module, collect running signals by steam drum liquid level, feedwater flow, steam flow, feedwater pressure, steam drum pressure and feedwater temperature sensor, output control signals after signal conditioning, data preprocessing and multi-parameter fusion adaptive PID control, drive frequency converter to adjust feedwater pump motor, and configure fault diagnosis and control mode management.The present application is suitable for the closed-loop control of power boiler feedwater system in the field.

Description

Technical Field

[0001] This invention relates to the field of electric boiler control technology, and in particular to an independent control device for boiler feedwater systems that integrates multi-parameter monitoring, adaptive control, and intelligent diagnostic functions. Background Technology

[0002] The feedwater system of an electric power boiler is a crucial component of the boiler operation control in thermal power generating units. It is typically used to adjust the feedwater flow rate based on operating parameters such as boiler drum liquid level, feedwater flow rate, and steam flow rate, ensuring that the boiler feedwater flow rate matches the evaporation rate. Common methods in existing boiler feedwater control include single-impulse control, three-impulse control, and proportional-integral-derivative (PID) control based on programmable logic controllers (PLCs) or distributed control systems (DCS). These solutions usually acquire boiler operating signals through level sensors, flow sensors, or pressure sensors. The controller then outputs adjustment signals based on preset control parameters to control feedwater regulating valves or feedwater pumps, thereby completing the closed-loop regulation of the boiler feedwater process.

[0003] In actual operation, the feedwater system of an electric boiler is affected by factors such as boiler load changes, steam flow rate changes, feedwater status changes, and drum pressure changes, making it prone to lag and false water level phenomena in the drum. Although existing three-impulse control can compensate for the drum water level to some extent using feedwater and steam flow rates, its control information is usually concentrated on a few parameters such as water level and flow rate, making it difficult to simultaneously combine parameters such as feedwater pressure, drum pressure, and feedwater temperature to reflect the comprehensive operating status of the boiler feedwater system. When boiler operating conditions change, fixed control parameters cannot match the current operating state in a timely manner, resulting in limited adaptability of the control and regulation process to complex operating conditions.

[0004] Furthermore, some existing solutions rely on software control logic in programmable logic controllers or distributed control systems to complete parameter adjustment. Field sensors, control logic, and execution devices are relatively dispersed, making the control process susceptible to influences from communication links and the status of the upper-level control system. This hinders the development of independent control devices suitable for boiler feedwater applications. Simultaneously, existing feedwater control solutions primarily focus on level regulation under normal operating conditions, lacking fault diagnosis and degradation control mechanisms that align with the control mode for situations such as abnormal sensor signals, flow or pressure parameter failures, and level signal failures. This makes it difficult to switch to the appropriate control mode based on the fault type under abnormal operating conditions.

[0005] In summary, existing technologies suffer from limitations such as limited dimensions of boiler feedwater control parameters, difficulty in adaptively adjusting control parameters according to comprehensive operating conditions, insufficient integration of sensor acquisition, control, and execution structures, and lack of hierarchical control mode switching under abnormal signals. Summary of the Invention

[0006] To address the shortcomings of existing technologies, such as limited dimensions of boiler feedwater control parameters, difficulty in adaptively adjusting control parameters according to comprehensive operating conditions, insufficient integration of sensor acquisition, control, and execution structures, and lack of hierarchical control mode switching under abnormal signals, the technical solution provided by this invention is as follows: A multi-parameter adaptive control device for a power boiler feedwater system includes: Multi-parameter sensor module, embedded intelligent controller module, and actuator control module; The multi-parameter sensor module includes a boiler drum liquid level sensor, a feedwater flow sensor, a steam flow sensor, a feedwater pressure sensor, a boiler drum pressure sensor, and a feedwater temperature sensor, which are respectively installed in the boiler drum, feedwater pipeline, and steam outlet pipeline. The embedded intelligent controller module includes a signal conditioning and A / D conversion module, a data preprocessing unit, a multi-parameter fusion adaptive PID control unit, and a main control microprocessor. The input terminal of the signal conditioning and A / D conversion module is electrically connected to the signal output terminal of the multi-parameter sensor module. The output terminal of the signal conditioning and A / D conversion module is electrically connected to the multi-parameter fusion adaptive PID control unit via the data preprocessing unit. The multi-parameter fusion adaptive PID control unit is electrically connected to the main control microprocessor. The actuator control module includes a frequency converter and a feedwater pump motor. The control output terminal of the multi-parameter fusion adaptive PID control unit is electrically connected to the control input terminal of the frequency converter, and the drive output terminal of the frequency converter is electrically connected to the feedwater pump motor. The feedwater pump motor is connected to the feedwater pump in the boiler feedwater pipeline.

[0007] Furthermore, in a preferred embodiment, each sensor in the multi-parameter sensor module has an independent signal output terminal, and each signal output terminal is connected to the corresponding input channel of the signal conditioning and A / D conversion module.

[0008] Furthermore, in a preferred embodiment, the data preprocessing unit is located in the signal transmission link between the signal conditioning and A / D conversion module and the multi-parameter fusion adaptive PID control unit.

[0009] Furthermore, in a preferred embodiment, the multi-parameter fusion adaptive PID control unit includes a spurious water level correction module and a PID parameter tuning module. The input terminal of the spurious water level correction module receives the steam drum liquid level signal, the feedwater flow rate signal, and the steam flow rate signal, respectively. The output terminal of the spurious water level correction module is electrically connected to the PID parameter tuning module.

[0010] Furthermore, in a preferred embodiment, the PID parameter tuning module also receives the feedwater temperature signal and the steam drum pressure signal, respectively, and the output terminal of the PID parameter tuning module is electrically connected to the control input terminal of the frequency converter.

[0011] Furthermore, in a preferred embodiment, the embedded intelligent controller module further includes a fault diagnosis and safety protection unit, the input terminal of which is electrically connected to the data preprocessing unit, and the output terminal of which is electrically connected to the multi-parameter fusion adaptive PID control unit.

[0012] Furthermore, in a preferred embodiment, the embedded intelligent controller module further includes a control mode management unit, which is electrically connected to the fault diagnosis and safety protection unit, the multi-parameter fusion adaptive PID control unit, and the control input terminal of the frequency converter.

[0013] Furthermore, in a preferred embodiment, the embedded intelligent controller module further includes a storage unit and a runtime cache unit, wherein the storage unit is electrically connected to the main control microprocessor, and the runtime cache unit is electrically connected to the main control microprocessor.

[0014] Furthermore, in a preferred embodiment, it also includes a human-machine interaction module, which is electrically connected to the embedded intelligent controller module and is used to input control mode commands and parameter setting signals to the embedded intelligent controller module.

[0015] A water supply system, including the aforementioned device.

[0016] A multi-parameter adaptive control method for a power boiler feedwater system, implemented based on the aforementioned device, includes: Collect the boiler feedwater system's drum liquid level signal, feedwater flow signal, steam flow signal, feedwater pressure signal, drum pressure signal, and feedwater temperature signal; The collected operating signals are subjected to signal conditioning, analog-to-digital conversion and data preprocessing to obtain the corresponding multi-parameter operating data; Feedforward compensation is performed on the steam drum liquid level signal based on the water flow signal and steam flow signal to obtain the corrected water level deviation signal; Based on the corrected water level deviation signal, the deviation change rate, and the comprehensive operating parameters formed by the feedwater temperature signal and the steam drum pressure signal, the PID control parameters are tuned and the feedwater control signal is generated. The water supply control signal is output to the frequency converter, which adjusts the speed of the water supply pump motor. Anomaly detection is performed on the multi-parameter operating data, and the multi-parameter adaptive control mode, single-impulse control mode, or manual control mode is switched according to the anomaly detection results.

[0017] Compared with the prior art, the advantages of the technical solution provided by the present invention are as follows: The multi-parameter sensor module simultaneously collects steam drum liquid level, feedwater flow rate, steam flow rate, feedwater pressure, steam drum pressure, and feedwater temperature. This allows the control device to no longer rely solely on steam drum liquid level or flow rate signals to determine the feedwater status. Instead, it can incorporate water level deviation, material inflow and outflow relationship, pressure status, and feedwater thermal status into the same control basis, thereby improving the problem of insufficient information dimensions in traditional single-impulse or three-impulse control.

[0018] The steam drum level sensor is used in conjunction with the feedwater flow sensor and the steam flow sensor to enable the steam drum level signal to be corrected based on the relationship between the feedwater and steam flow rates. This avoids adjustments based solely on the instantaneous rise and fall of the level when the load changes, thereby reducing the interference of false water levels on the direction and magnitude of feedwater regulation.

[0019] Feedwater pressure sensor, steam drum pressure sensor, and feedwater temperature sensor are integrated into the same data acquisition system, enabling the control device to identify the impact of feedwater-side pressure changes, steam drum-side pressure changes, and feedwater temperature changes on the feedwater regulation process. This improves the problem of insufficient response of existing control schemes to the comprehensive operating conditions of the boiler and provides more complete operating status input for subsequent adaptive adjustment of control parameters.

[0020] The signal conditioning and A / D conversion module is located between the multi-parameter sensor module and the embedded intelligent controller module. This allows the field analog signals output by each sensor to undergo unified conditioning and digital conversion before being input into the controller for fusion processing. This reduces the impact of inconsistent sensor signal specifications on control calculations and enables multiple operating parameters to be processed synchronously on the same control platform.

[0021] The embedded intelligent controller module integrates a main control microprocessor, Flash memory, SDRAM, and input / output interfaces, enabling multi-parameter acquisition, control algorithm execution, data caching, and execution signal output to be completed in a dedicated hardware device. It does not require real-time calculations based entirely on the software logic of the upper-level distributed control system, reducing response delays and control interruption risks caused by the dispersed field control links.

[0022] Flash memory is used to store multi-parameter fusion adaptive PID control algorithms, so that the control logic runs in the local control device. SDRAM is used for runtime data caching, so that real-time acquired multi-parameter data and intermediate control calculation quantities can be continuously called, thereby improving the controller's ability to continuously process load fluctuations and parameter changes.

[0023] The multi-parameter fusion adaptive PID control algorithm adjusts the PID control parameters in real time based on six operating parameters, so that the controller no longer uses fixed proportional, integral, and derivative parameters for a long time. Instead, it can correct the control parameters online according to the deviation of the steam drum liquid level, changes in flow rate, changes in pressure, and changes in temperature, thereby improving the problem of insufficient adaptability of fixed parameter control when the boiler operating conditions change.

[0024] By using the signals from the feedwater flow sensor and the steam flow sensor to feedforward compensate the signal from the steam drum level sensor, the controller can correct the level deviation signal based on the difference between the feedwater input and the steam output. When false water level phenomena such as expansion or contraction occur, the controller's misjudgment of apparent level changes is reduced, making the feedwater regulation closer to the actual water level requirement.

[0025] The fuzzy neural network model takes the corrected water level deviation, deviation change rate, and comprehensive operating condition parameters as inputs and outputs the PID control parameter adjustment amount. This makes the control parameter tuning no longer only focus on the water level deviation itself, but also make a comprehensive judgment based on the deviation change trend and the boiler load change trend, thereby improving the adaptability of control parameter adjustment to complex operating conditions.

[0026] The comprehensive operating parameters, calculated by weighting the feedwater temperature and steam drum pressure signals, are used to reflect the trend of boiler load changes. This enables the control algorithm to adjust the control parameters in advance when the steam drum pressure changes continuously or the feedwater thermal state changes, rather than passively adjusting them after the steam drum liquid level deviates significantly. This improves the problem of feedwater regulation lag in the early stage of load changes.

[0027] The fault diagnosis and safety protection unit performs real-time validity detection of sensor signals, enabling the control device to identify abnormal sensor signals and trigger alarms and protection actions. This prevents abnormal signals from continuing to participate in multi-parameter fusion control and causing incorrect adjustments, thereby improving the safety of water supply control under abnormal operating conditions.

[0028] The control mode management unit switches between multi-parameter adaptive control mode, single-impulse control mode and manual control mode, enabling the device to select different operating modes according to the sensor fault type. Under normal operating conditions, multi-parameter fusion control is adopted. When some flow or pressure sensors fail, it degrades to single-impulse control with steam drum liquid level as the core. When the liquid level sensor fails or receives operator instructions, it switches to manual control, which improves the problem of the lack of a graded degraded operation mechanism in the existing control scheme.

[0029] The frequency converter in the actuator control module adjusts the speed of the water pump motor according to the control signal output by the embedded intelligent controller module, so that the water flow rate is adjusted by changing the pump speed, instead of simply relying on the throttling control of the water flow regulating valve. This allows the control output to directly act on the water supply power equipment, improving the consistency of execution between the control signal and the change in water flow rate.

[0030] The feedwater pump motor and frequency converter, as the actuators, work in conjunction with the embedded intelligent controller module to form a closed loop, creating a continuous control link between sensor acquisition, control parameter calculation, and feedwater pump speed regulation. This improves the problem of relatively dispersed acquisition, control, and execution links in existing solutions and enhances the integration of the boiler feedwater field control device.

[0031] The human-machine interface module is connected to the embedded intelligent controller module to display real-time data, set parameters, query historical curves, and issue alarm prompts. This allows operators to directly understand the multi-parameter operating and control status on-site and to set parameters or intervene in abnormal situations, thereby improving the operability of the device in on-site operation and maintenance.

[0032] The communication module connects to the distributed control system or remote monitoring center via RS485 and Ethernet communication interfaces, enabling independent control devices to upload operational data and receive remote commands while maintaining local closed-loop control capabilities. This balances the needs of real-time on-site control and monitoring by higher-level systems, avoiding complete reliance on remote systems to execute core control logic. Attached Figure Description

[0033] Figure 1 This is a block diagram of the overall structure of a multi-parameter adaptive control device for a power boiler feedwater system.

[0034] Figure 2 This is a schematic diagram of the installation of a multi-parameter sensor module in a multi-parameter adaptive control device for a power boiler feedwater system.

[0035] Figure 3 This is a hardware structure block diagram of an embedded intelligent controller module in a multi-parameter adaptive control device for a power boiler feedwater system.

[0036] Figure 4 This is a flowchart of a multi-parameter fusion adaptive PID control algorithm in a multi-parameter adaptive control device for a power boiler feedwater system.

[0037] Figure 5 This is a block diagram of the multi-parameter fusion adaptive PID control principle in a multi-parameter adaptive control device for a power boiler feedwater system.

[0038] Figure 6 This is a fault diagnosis and safety protection logic diagram for a multi-parameter adaptive control device for a power boiler feedwater system.

[0039] Figure 7 This is a state diagram showing the control mode switching in a multi-parameter adaptive control device for a power boiler feedwater system.

[0040] Figure 8This is a schematic diagram of the human-machine interface in a multi-parameter adaptive control device for a power boiler feedwater system.

[0041] In the attached diagram: 1. Steam drum level sensor; 2. Feedwater flow sensor; 3. Steam flow sensor; 4. Feedwater pressure sensor; 5. Steam drum pressure sensor; 6. Feedwater temperature sensor; 7. Signal conditioning and A / D conversion module; 8. Data preprocessing unit; 9. Multi-parameter fusion adaptive PID control unit; 10. Fault diagnosis and safety protection unit; 11. Control mode management unit; 12. Frequency converter; 13. Feedwater pump motor; 14. Human-machine interface module; 15. Communication module; 16. Main control microprocessor; 17. Multi-channel A / D conversion module; 18. D / A conversion and output module; 19. Flash memory; 20. SDRAM; 21. RS485 communication interface; 22. Ethernet communication interface; 23. Display interface; 24. Switch I / O interface; 25. Power supply module; 26. Real-time clock (RTC); 27. Watchdog timer (WDT); A. Multi-parameter sensor module; B. Embedded intelligent controller module; C. Actuator control module. Detailed Implementation

[0042] To make the advantages and benefits of the technical solution provided by the present invention clearer, the technical solution provided by the present invention will now be described in further detail with reference to the accompanying drawings, specifically: Implementation Method 1: This implementation method provides a multi-parameter adaptive control device for a power boiler feedwater system, comprising: Multi-parameter sensor module, embedded intelligent controller module, and actuator control module; The multi-parameter sensor module includes a boiler drum liquid level sensor, a feedwater flow sensor, a steam flow sensor, a feedwater pressure sensor, a boiler drum pressure sensor, and a feedwater temperature sensor, which are respectively installed in the boiler drum, feedwater pipeline, and steam outlet pipeline. The embedded intelligent controller module includes a signal conditioning and A / D conversion module, a data preprocessing unit, a multi-parameter fusion adaptive PID control unit, and a main control microprocessor. The input terminal of the signal conditioning and A / D conversion module is electrically connected to the signal output terminal of the multi-parameter sensor module. The output terminal of the signal conditioning and A / D conversion module is electrically connected to the multi-parameter fusion adaptive PID control unit via the data preprocessing unit. The multi-parameter fusion adaptive PID control unit is electrically connected to the main control microprocessor. The actuator control module includes a frequency converter and a feedwater pump motor. The control output terminal of the multi-parameter fusion adaptive PID control unit is electrically connected to the control input terminal of the frequency converter, and the drive output terminal of the frequency converter is electrically connected to the feedwater pump motor. The feedwater pump motor is connected to the feedwater pump in the boiler feedwater pipeline.

[0043] Each sensor in the multi-parameter sensor module has an independent signal output terminal, and each signal output terminal is connected to the corresponding input channel of the signal conditioning and A / D conversion module.

[0044] The data preprocessing unit is located in the signal transmission link between the signal conditioning and A / D conversion module and the multi-parameter fusion adaptive PID control unit.

[0045] The multi-parameter fusion adaptive PID control unit includes a false water level correction module and a PID parameter tuning module. The input terminal of the false water level correction module receives the steam drum liquid level signal, the feedwater flow signal, and the steam flow signal, respectively. The output terminal of the false water level correction module is electrically connected to the PID parameter tuning module.

[0046] The PID parameter tuning module also receives feedwater temperature signal and steam drum pressure signal respectively, and the output terminal of the PID parameter tuning module is electrically connected to the control input terminal of the frequency converter.

[0047] The embedded intelligent controller module also includes a fault diagnosis and safety protection unit. The input terminal of the fault diagnosis and safety protection unit is electrically connected to the data preprocessing unit, and the output terminal of the fault diagnosis and safety protection unit is electrically connected to the multi-parameter fusion adaptive PID control unit.

[0048] The embedded intelligent controller module also includes a control mode management unit, which is electrically connected to the fault diagnosis and safety protection unit, the multi-parameter fusion adaptive PID control unit, and the control input terminal of the frequency converter.

[0049] The embedded intelligent controller module further includes a storage unit and a runtime cache unit. The storage unit is electrically connected to the main control microprocessor, and the runtime cache unit is electrically connected to the main control microprocessor.

[0050] It also includes a human-computer interaction module, which is electrically connected to the embedded intelligent controller module and is used to input control mode commands and parameter setting signals to the embedded intelligent controller module.

[0051] A water supply system, including the aforementioned device.

[0052] A multi-parameter adaptive control method for a power boiler feedwater system, implemented based on the aforementioned device, includes: Collect the boiler feedwater system's drum liquid level signal, feedwater flow signal, steam flow signal, feedwater pressure signal, drum pressure signal, and feedwater temperature signal; The collected operating signals are subjected to signal conditioning, analog-to-digital conversion and data preprocessing to obtain the corresponding multi-parameter operating data; Feedforward compensation is performed on the steam drum liquid level signal based on the water flow signal and steam flow signal to obtain the corrected water level deviation signal; Based on the corrected water level deviation signal, the deviation change rate, and the comprehensive operating parameters formed by the feedwater temperature signal and the steam drum pressure signal, the PID control parameters are tuned and the feedwater control signal is generated. The water supply control signal is output to the frequency converter, which adjusts the speed of the water supply pump motor. Anomaly detection is performed on the multi-parameter operating data, and the multi-parameter adaptive control mode, single-impulse control mode, or manual control mode is switched according to the anomaly detection results.

[0053] Implementation Method Two: This implementation method is a further detailed description of the technical solution provided in Implementation Method One, specifically: This embodiment provides a multi-parameter adaptive control device for a power boiler feedwater system, including a multi-parameter sensor module A, an embedded intelligent controller module B, and an actuator control module C. The multi-parameter sensor module A is located at the parameter detection position of the boiler feedwater system. The embedded intelligent controller module B is set as an independent control unit. The output terminal of the multi-parameter sensor module A is electrically connected to the input terminal of the embedded intelligent controller module B, and the output terminal of the embedded intelligent controller module B is electrically connected to the input terminal of the actuator control module C. The actuator control module C is connected to the feedwater equipment, so that the operating signals collected by the multi-parameter sensor module A are processed by the embedded intelligent controller module B and then output to the actuator control module C.

[0054] The multi-parameter sensor module A includes a steam drum level sensor 1, a feedwater flow sensor 2, a steam flow sensor 3, a feedwater pressure sensor 4, a steam drum pressure sensor 5, and a feedwater temperature sensor 6. The steam drum level sensor 1 is located at the level detection position on the boiler drum. The feedwater flow sensor 2, feedwater pressure sensor 4, and feedwater temperature sensor 6 are installed along the feedwater pipeline. The steam flow sensor 3 is installed on the steam outlet pipeline of the steam drum, and the steam drum pressure sensor 5 is installed at the pressure detection position on the steam drum. The signal output terminals of each sensor are connected to the embedded intelligent controller module B, allowing the steam drum level signal, feedwater flow signal, steam flow signal, feedwater pressure signal, steam drum pressure signal, and feedwater temperature signal to be transmitted to the embedded intelligent controller module B respectively.

[0055] The embedded intelligent controller module B includes a signal conditioning and A / D conversion module 7, a data preprocessing unit 8, a multi-parameter fusion adaptive PID control unit 9, a fault diagnosis and safety protection unit 10, a control mode management unit 11, a main control microprocessor 16, a multi-channel A / D conversion module 17, a D / A conversion and output module 18, a Flash memory 19, an SDRAM 20, a digital I / O interface 24, and a power supply module 25. The input terminal of the signal conditioning and A / D conversion module 7 is electrically connected to the multi-parameter sensor module A, and the output terminal of the signal conditioning and A / D conversion module 7 is electrically connected to the multi-channel A / D conversion module 17. The multi-channel A / D conversion module 17 is electrically connected to the main control microprocessor 16, enabling the analog signals output from each sensor to be conditioned and converted from analog to digital before being input to the main control microprocessor 16.

[0056] The main control microprocessor 16 is electrically connected to the data preprocessing unit 8, the multi-parameter fusion adaptive PID control unit 9, the fault diagnosis and safety protection unit 10, the control mode management unit 11, the Flash memory 19, and the SDRAM 20. The Flash memory 19 is used to store the control program called by the multi-parameter fusion adaptive PID control unit 9, and the SDRAM 20 is used to cache sensor-acquired data and control calculation data. The data preprocessing unit 8 is located in the signal processing link between the multi-channel A / D conversion module 17 and the multi-parameter fusion adaptive PID control unit 9, so that the multiple signals input to the multi-parameter fusion adaptive PID control unit 9 have a unified data format.

[0057] The multi-parameter fusion adaptive PID control unit 9 is signal-connected to the data preprocessing unit 8 and receives the steam drum liquid level signal, feedwater flow rate signal, steam flow rate signal, feedwater pressure signal, steam drum pressure signal, and feedwater temperature signal, respectively. The multi-parameter fusion adaptive PID control unit 9 is equipped with a feedforward compensation operation structure and a parameter tuning operation structure. The feedforward compensation operation structure receives the feedwater flow rate signal, steam flow rate signal, and steam drum liquid level signal to generate a corrected water level deviation signal. The parameter tuning operation structure receives the corrected water level deviation signal, the deviation change rate, and the comprehensive operating condition signal formed by the feedwater temperature signal and the steam drum pressure signal, and transmits the control output to the D / A conversion and output module 18.

[0058] The input terminal of the D / A conversion and output module 18 is electrically connected to the main control microprocessor 16, and the output terminal of the D / A conversion and output module 18 is electrically connected to the actuator control module C. The actuator control module C includes a frequency converter 12 and a water pump motor 13. The control input terminal of the frequency converter 12 is electrically connected to the D / A conversion and output module 18, and the drive output terminal of the frequency converter 12 is electrically connected to the water pump motor 13. This allows the control signal output by the embedded intelligent controller module B to be input to the frequency converter 12 after D / A conversion, and the frequency converter 12 to regulate the speed of the water pump motor 13.

[0059] The fault diagnosis and safety protection unit 10 is electrically connected to the data preprocessing unit 8, the control mode management unit 11, and the digital I / O interface 24. The fault diagnosis and safety protection unit 10 receives the sensor signals processed by the data preprocessing unit 8 and outputs a fault type signal to the control mode management unit 11. The digital I / O interface 24 is electrically connected to external start / stop terminals, alarm terminals, and interlock protection terminals, enabling the output of alarm signals or interlock protection signals through the digital I / O interface 24 when sensor signals are abnormal.

[0060] The control mode management unit 11 is connected to the multi-parameter fusion adaptive PID control unit 9, the fault diagnosis and safety protection unit 10, the human-machine interface module 14, and the D / A conversion and output module 18. The control mode management unit 11 is configured with a multi-parameter adaptive control mode, a single-impulse control mode, and a manual control mode. When the fault diagnosis and safety protection unit 10 outputs an abnormal signal from a flow or pressure sensor, the control mode management unit 11 switches the control link to the single-impulse control mode. When the fault diagnosis and safety protection unit 10 outputs an abnormal signal from the steam drum level sensor 1 or the human-machine interface module 14 inputs a manual control command, the control mode management unit 11 switches the control link to the manual control mode.

[0061] This device also includes a human-machine interface module 14 and a communication module 15. The human-machine interface module 14 is electrically connected to the main control microprocessor 16 via a display screen interface 23. The signal input terminal of the human-machine interface module 14 is electrically connected to the control mode management unit 11, enabling the transmission of setting parameters or control mode commands input by the operator to the control mode management unit 11. The communication module 15 includes an RS485 communication interface 21 and an Ethernet communication interface 22. The RS485 communication interface 21 and the Ethernet communication interface 22 are electrically connected to the main control microprocessor 16 and are used for communication with a distributed control system or remote monitoring center, enabling the embedded intelligent controller module B to upload operating data and receive remote commands.

[0062] The power supply module 25 is electrically connected to the main control microprocessor 16, the multi-channel A / D conversion module 17, the D / A conversion and output module 18, the Flash memory 19, the SDRAM 20, the human-machine interaction module 14, and the communication module 15, respectively. The embedded intelligent controller module B also includes a real-time clock 26 and a watchdog timer 27. The real-time clock 26 is electrically connected to the main control microprocessor 16 and is used to provide time signals for the running data. The watchdog timer 27 is electrically connected to the main control microprocessor 16 and is used to output a reset signal to the main control microprocessor 16 when the main control microprocessor 16 malfunctions.

[0063] In use, the multi-parameter sensor module A collects six operating signals from the boiler feedwater system and the steam drum. Each operating signal is input to the main control microprocessor 16 via the signal conditioning and A / D conversion module 7 and the multi-channel A / D conversion module 17. The main control microprocessor 16 calls the control program in the Flash memory 19 and performs calculations in combination with the cached data in the SDRAM 20. The resulting control output is transmitted to the frequency converter 12 via the D / A conversion and output module 18. The frequency converter 12 drives the feedwater pump motor 13 to change its speed. When the signal is abnormal, the fault diagnosis and safety protection unit 10 transmits the fault type signal to the control mode management unit 11. The control mode management unit 11 adjusts the control link according to the fault type and outputs the corresponding alarm signal or interlock protection signal through the switch I / O interface 24.

[0064] A multi-parameter adaptive control method for a power boiler feedwater system is disclosed, applicable to closed-loop control of boiler drum water level and feedwater flow rate. During the control process, the following signals are collected: boiler drum water level sensor, feedwater flow rate sensor, steam flow rate sensor, feedwater pressure sensor, boiler drum pressure sensor, and feedwater temperature sensor.

[0065] The operating signals output from each sensor are input to the signal conditioning and A / D conversion module. After signal conditioning and analog-to-digital conversion, they are converted into digital signals and then input to the data preprocessing unit. The data preprocessing unit filters, calibrates, and normalizes each digital signal to form multi-parameter operating data in a unified format, including steam drum level, feedwater flow rate, steam flow rate, feedwater pressure, steam drum pressure, and feedwater temperature.

[0066] During normal control, the relationship between the feedwater input and steam output is determined based on the feedwater flow and steam flow signals. This relationship is then used as a feedforward compensation factor to the drum level signal, resulting in a corrected level deviation signal. Through this process, the control process does not rely solely on the instantaneous change in the drum level; instead, it combines feedwater and steam flow rates to correct the drum level.

[0067] Subsequently, the water level deviation is calculated based on the corrected water level deviation signal, and the deviation change rate is calculated based on the water level deviation changes in adjacent control cycles. Simultaneously, comprehensive operating parameters are formed based on the feedwater temperature signal and the steam drum pressure signal. These comprehensive operating parameters serve as auxiliary inputs reflecting the boiler load change trend and are input together with the water level deviation and deviation change rate into the multi-parameter fusion adaptive PID control unit.

[0068] The multi-parameter fusion adaptive PID control unit tunes the PID control parameters online based on water level deviation, deviation change rate, and comprehensive operating parameters to obtain the adjustment amounts of proportional, integral, and derivative parameters. It then generates a feedwater control signal based on the adjusted PID control parameters. This feedwater control signal is converted from a digital signal to an analog-to-digital converter (D / A converter) and output to the frequency converter. The frequency converter adjusts the feedwater pump motor speed according to the feedwater control signal to change the water flow rate in the boiler feedwater pipeline.

[0069] During the control process, the fault diagnosis and safety protection unit continuously receives pre-processed multi-parameter operating data and determines whether the signals of each sensor are within the valid range. When all sensor signals are normal, the control mode management unit maintains the multi-parameter adaptive control mode; when the feedwater flow signal, steam flow signal, feedwater pressure signal, or steam drum pressure signal is abnormal, the control mode management unit switches to the single-impulse control mode and uses the steam drum liquid level signal as the main control basis; when the steam drum liquid level signal is abnormal or a manual control command is received from the operator, the control mode management unit switches to the manual control mode, and the operator sets the operating frequency of the feedwater pump motor.

[0070] Implementation Method 3: This implementation method is described in detail with reference to the accompanying drawings. Specific embodiments are provided to further illustrate the technical solution provided above. Specifically: This embodiment discloses a multi-parameter adaptive control device for a power boiler feedwater system, comprising a multi-parameter sensor module A, which includes a steam drum level sensor 1, a feedwater flow sensor 2, a steam flow sensor 3, a feedwater pressure sensor 4, a steam drum pressure sensor 5, and a feedwater temperature sensor 6, used to collect signals of six key operating parameters of the boiler feedwater system; an embedded intelligent controller module B, whose input terminal is connected to the multi-parameter sensor module A via a signal conditioning and A / D conversion module 7; the embedded intelligent controller module B includes a main control microprocessor 16, a Flash memory 19 for storing a multi-parameter fusion adaptive PID control algorithm, an SDRAM 20 for runtime data caching, and input / output interfaces connected to the sensors and actuators; the multi-parameter fusion adaptive PID control algorithm is used to adjust the PID control parameters in real time according to the signals of the six parameters and output control signals; and an actuator control module C, whose input terminal is connected to the output terminal of the embedded intelligent controller module B, used to receive the control signals and drive the feedwater equipment.

[0071] The embedded intelligent controller module B also integrates a fault diagnosis and safety protection unit 10, which is used to realize sensor fault diagnosis, equipment interlock protection and control mode switching. The fault diagnosis and safety protection unit 10 integrated in the embedded intelligent controller module B mainly performs real-time validity detection of sensor signals. When an abnormal signal is detected, an alarm is triggered and corresponding protection actions are executed. At the same time, the control mode is automatically switched according to the fault type to ensure that the system can operate safely and reliably under any working conditions.

[0072] The control mode switching includes switching between multi-parameter adaptive control mode, single-impulse control mode, and manual control mode. Specifically, when the flow or pressure sensor fails, it automatically degrades to single-impulse control mode; when the level sensor fails or an operator command is received, it switches to manual control mode. This control mode switching mechanism enables the system to operate under multi-level degradation capabilities. The multi-parameter adaptive control mode is the default operating mode under normal conditions, utilizing all six parameters for integrated control. The single-impulse control mode performs basic PID control based solely on the steam drum level when a minor sensor fails. The manual control mode allows operators to directly set the feedwater pump output frequency, ensuring the system can continue operating safely or shut down smoothly under any sensor failure or abnormal operating conditions.

[0073] The multi-parameter fusion adaptive PID control algorithm includes using the signals from the water flow sensor 2 and the steam flow sensor 3 to perform feedforward compensation on the signal from the steam drum level sensor 1 to correct false water levels. The feedforward compensation mechanism uses the water flow and steam flow signals to calculate the material balance deviation, thereby correcting the false water level phenomenon caused by changes in operating conditions such as expansion or contraction, so that the controller obtains a more realistic level deviation signal, effectively improving control accuracy and system stability.

[0074] The multi-parameter fusion adaptive PID control algorithm adopts a fuzzy neural network model. The fuzzy neural network model uses the corrected water level deviation E, the deviation change rate EC, and a comprehensive operating condition parameter W, which reflects the boiler load change trend and is calculated by weighting the feedwater temperature and steam drum pressure signals, as feedforward compensation inputs. The adjustment amounts ΔKp, ΔKi, and ΔKd of the PID control parameters are tuned online. The fuzzy neural network model innovatively introduces feedwater temperature and steam drum pressure as auxiliary parameters to achieve predictive control. When the steam drum pressure is detected to be continuously decreasing, the model interprets it as a precursor to an upcoming increase in boiler load and adjusts the PID parameters in advance to make the feedwater flow increase gradually, thereby achieving a qualitative change from passive response to active prediction.

[0075] The actuator control module C includes a frequency converter 12 and a water pump motor 13. The frequency converter 12 adjusts the speed of the water pump motor 13 according to the control signal. The main function of the frequency converter 12 and the water pump motor 13 in the actuator control module C is to convert the control signal output by the embedded intelligent controller module B into precise adjustment of the water pump speed. By replacing the throttling control of the traditional water supply regulating valve with frequency conversion speed regulation, the throttling loss is avoided, and precise control of water supply flow with high efficiency and energy saving is achieved.

[0076] It also includes a human-machine interaction module 14 and a communication module 15, both connected to the embedded intelligent controller module B; the communication module 15 includes an RS485 communication interface 21 and / or an Ethernet communication interface 22, and the human-machine interaction module 14 is a touch screen display used to display real-time data, set parameters, query historical curves, and issue alarm prompts; the communication module 15 is used to upload the device's operating data to the power plant's distributed control system (DCS) or remote monitoring center and receive remote commands, thereby realizing a complete closed-loop function from data acquisition, intelligent decision-making, frequency conversion execution to fault diagnosis, safety protection, and human-machine interaction.

[0077] The advantages of this technology in optimizing the control of power boiler feedwater systems are as follows: 1. This implementation method uses a multi-parameter sensor module A to collect six key operating parameters in real time: steam drum liquid level, feedwater flow rate, steam flow rate, feedwater pressure, steam drum pressure, and feedwater temperature. This far exceeds the two to three parameters commonly found in existing technologies. Combined with the fuzzy neural network adaptive PID control algorithm integrated within the embedded intelligent controller module B, feedwater temperature and steam drum pressure are innovatively introduced as feedforward compensation parameters, realizing predictive control. This enables the system to shift from passively responding to deviations to actively predicting operating conditions, greatly improving control accuracy and system stability under drastic load changes. Simulation tests show that under a simulated 50% step load disturbance, the maximum deviation of the steam drum water level is reduced by more than 60%, and the adjustment time is shortened by about 40%.

[0078] 2. This implementation method embeds the control algorithm into an independent embedded hardware platform, and the control logic runs at high speed in the local main control microprocessor 16 with a control cycle of up to 100ms. This completely avoids the communication delay and host computer failure risk that exist in the DCS system software solution. At the same time, it integrates the fault diagnosis and safety protection unit 10 and the control mode management unit 11, realizing sensor fault self-diagnosis, multi-level safety protection and multi-mode degradation operation strategy, ensuring that the system can continue to operate or shut down smoothly in the safest and most reliable way under any sensor failure or abnormal working conditions.

[0079] 3. This implementation method uses the frequency converter 12 in the actuator control module C to precisely control the speed of the water pump motor 13 to regulate the flow rate, replacing the throttling control method of the traditional water supply regulating valve, avoiding throttling losses and achieving high efficiency and energy saving; at the same time, it integrates a complete closed-loop function from data acquisition, intelligent decision-making, frequency conversion execution to fault diagnosis, safety protection, human-machine interaction and remote communication in a single device, providing a one-stop solution and significantly improving the system integration and reliability.

[0080] Please see Figure 1-8 This embodiment describes a multi-parameter adaptive control device for a power boiler feedwater system. It consists of three main functional modules and two auxiliary modules: a multi-parameter sensor module A, an embedded intelligent controller module B, an actuator control module C, a human-machine interface module 14, and a communication module 15. The signal flow between the three main functional modules is as follows: the multi-parameter sensor module A outputs six collected analog signals to the embedded intelligent controller module B; after data processing and algorithm calculation, the embedded intelligent controller module B outputs control signals to the actuator control module C, forming a complete closed-loop control circuit.

[0081] Specifically: such as Figure 2As shown, the installation locations of the multi-parameter sensor module A cover the key nodes of the boiler feedwater system. Steam drum level sensor 1 is installed on the side wall of the boiler steam drum to directly measure the steam drum water level, with a range of -300mm to +300mm. Feedwater flow sensor 2 is installed on the feedwater pipe before entering the boiler, with a range of 0-150t / h. Feedwater pressure sensor 4 is installed on the feedwater pipe, with a range of 0-25MPa. Feedwater temperature sensor 6 is installed on the feedwater pipe, with a range of 0-350℃. Steam flow sensor 3 is installed on the steam outlet pipe of the steam drum, with a range of 0-200t / h. Steam drum pressure sensor 5 is installed on the top of the steam drum, with a range of 0-10MPa. All of the above sensors convert the collected physical quantities into a standard 4-20mA current signal output. These analog signals are first sent to the signal conditioning and A / D conversion module 7 of the embedded intelligent controller module B. This module is responsible for photoelectric isolation, low-pass filtering and linear amplification of the signals. Then, they are converted into digital signals by a 16-bit high-precision analog-to-digital converter (ADC) with a sampling accuracy of up to 0.01%FS.

[0082] like Figure 3 As shown, the core of the embedded intelligent controller module B is a high-performance 32-bit main control microprocessor 16, using an ARM Cortex-M4 core MCU with a main frequency of 168MHz. It connects to various peripherals through an internal bus. A multi-channel A / D conversion module 17 receives signals from sensors. The main control microprocessor 16 reads data from the A / D conversion module 17 and processes it in the internal SDRAM 20. The control algorithm and system program are stored in the Flash memory 19. The real-time clock RTC 26 provides precise timestamps for data recording and trend analysis. The watchdog timer WDT 27 ensures the system can automatically reset in case of unexpected situations, improving system reliability. The digital I / O interface 24 receives external start / stop commands and outputs alarm and interlock signals. The D / A conversion and output module 18 converts the control results calculated by the processor into 4-20mA analog signals, which are output to the inverter 12 through the inverter control interface. The human-machine interface module 14 connects to the main control microprocessor 16 through the display interface 23. The communication module 15 communicates with the host computer system via RS485 communication interface 21 or Ethernet communication interface 22. The entire module is powered by a stable 24V DC power supply module 25. The control cycle of the entire controller is set to 100ms, the RS485 communication rate of the communication module 15 is 9600bps, and the Ethernet communication rate is 10 / 100Mbps adaptive.

[0083] like Figure 4 and Figure 5As shown, the multi-parameter fusion adaptive PID control unit 9 within the main control microprocessor 16 is the control core. Within a 100ms control cycle, its workflow is as follows: First, the signal conditioning and A / D conversion module 7 synchronously acquires data from six sensors; then, the data preprocessing unit 8 performs digital filtering on the received sensor signals, using weighted moving average filtering, scaling transformation, and normalization to eliminate noise interference and unify the data format; next, the fault diagnosis and safety protection unit 10 performs validity testing on the preprocessed data to determine if the signal is within a reasonable range; subsequently, the feedwater flow rate and steam flow rate signals are used to perform feedforward compensation on the drum liquid level signal to calculate the deviation in material balance, thereby correcting the false water level caused by changes in operating conditions and obtaining a more realistic liquid level deviation signal; then, the corrected water level deviation E and its rate of change EC are used as the main input, while feedwater temperature and drum pressure are introduced as auxiliary inputs. Through a preset fuzzy neural network model, inference calculations are performed to output the real-time adjustment amounts ΔKp, ΔKi, of the PID parameters. ΔKd; Finally, the final control output u(t) is calculated based on the adjusted PID parameters. This output is converted into a standard 4-20mA current signal or digital frequency signal and sent to the frequency converter 12 to control the speed of the water pump motor 13.

[0084] like Figure 6 As shown, the fault diagnosis and safety protection unit 10 judges the validity of sensor signals and the safety of key process parameters such as the steam drum water level in parallel. Regarding sensor fault diagnosis, the system monitors in real time whether the signals of each sensor are within a reasonable range, such as signal disconnection or exceeding the range, analyzes the signal jump rate, and diagnoses and alarms abnormal signals. Regarding equipment interlock protection, when dangerous conditions such as the steam drum water level exceeding the high-high HH limit or falling below the low-low LL limit, or abnormal feedwater pressure are detected, the interlock protection logic is triggered, forcibly adjusting or stopping the feedwater pump, and issuing audible and visual alarm signals.

[0085] like Figure 7 As shown, the control mode management unit 11 can switch between the following three modes: multi-parameter adaptive control mode is the default operating mode under normal working conditions, which uses all six parameters for integrated control; single-impulse control mode automatically degrades and switches when secondary sensors such as flow or pressure fail, and only performs basic PID control based on the steam drum liquid level to ensure the basic operation of the system; manual control mode switches when critical liquid level sensor fails or when operator instructions are received, and the operator manually sets the output frequency of the feedwater pump through the human-machine interaction module 14.

[0086] like Figure 8As shown, the human-machine interaction module 14 has an intuitive and user-friendly interface design. Operators can use this interface to intuitively monitor all key parameters of the boiler feedwater system, view real-time and historical trend curves, set control parameters, and receive alarm information, which greatly facilitates on-site operation and maintenance.

[0087] The working principle of this implementation is as follows: During operation, the multi-parameter sensor module A collects six key operating parameters of the boiler feedwater system in real time and converts them into standard current signals. After processing by the signal conditioning and A / D conversion module 7, the signals are sent to the embedded intelligent controller module B. The main control microprocessor 16 preprocesses the data and corrects for false water levels. Then, it comprehensively analyzes the changing trends of the six parameters through a fuzzy neural network adaptive PID control algorithm, adjusts the PID control parameters online in real time, and calculates the optimal control output. This control signal is output to the frequency converter 12 in the actuator control module C via the D / A conversion and output module 18 to precisely adjust the speed of the feedwater pump motor 13 and achieve precise control of the feedwater flow. At the same time, the fault diagnosis and safety protection unit 10 continuously monitors the system operating status and automatically switches the control mode or executes interlock protection under abnormal operating conditions to ensure the safe and stable operation of the boiler.

[0088] The above description of several specific embodiments further details the technical solution provided by the present invention in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the above-described specific embodiments are not intended to limit the present invention. Any reasonable modifications and improvements to the present invention, combinations of embodiments, and equivalent substitutions based on the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-parameter adaptive control device for a power boiler feedwater system, characterized in that, include: Multi-parameter sensor module, embedded intelligent controller module, and actuator control module; The multi-parameter sensor module includes a boiler drum liquid level sensor, a feedwater flow sensor, a steam flow sensor, a feedwater pressure sensor, a boiler drum pressure sensor, and a feedwater temperature sensor, which are respectively installed in the boiler drum, feedwater pipeline, and steam outlet pipeline. The embedded intelligent controller module includes a signal conditioning and A / D conversion module, a data preprocessing unit, a multi-parameter fusion adaptive PID control unit, and a main control microprocessor. The input terminal of the signal conditioning and A / D conversion module is electrically connected to the signal output terminal of the multi-parameter sensor module. The output terminal of the signal conditioning and A / D conversion module is electrically connected to the multi-parameter fusion adaptive PID control unit via the data preprocessing unit. The multi-parameter fusion adaptive PID control unit is electrically connected to the main control microprocessor. The actuator control module includes a frequency converter and a feedwater pump motor. The control output terminal of the multi-parameter fusion adaptive PID control unit is electrically connected to the control input terminal of the frequency converter, and the drive output terminal of the frequency converter is electrically connected to the feedwater pump motor. The feedwater pump motor is connected to the feedwater pump in the boiler feedwater pipeline.

2. The multi-parameter adaptive control device for a power boiler feedwater system according to claim 1, characterized in that, Each sensor in the multi-parameter sensor module has an independent signal output terminal, and each signal output terminal is connected to the corresponding input channel of the signal conditioning and A / D conversion module.

3. The multi-parameter adaptive control device for a power boiler feedwater system according to claim 1, characterized in that, The data preprocessing unit is located in the signal transmission link between the signal conditioning and A / D conversion module and the multi-parameter fusion adaptive PID control unit.

4. The multi-parameter adaptive control device for a power boiler feedwater system according to claim 1, characterized in that, The multi-parameter fusion adaptive PID control unit includes a false water level correction module and a PID parameter tuning module. The input terminal of the false water level correction module receives the steam drum liquid level signal, the feedwater flow signal, and the steam flow signal, respectively. The output terminal of the false water level correction module is electrically connected to the PID parameter tuning module.

5. The multi-parameter adaptive control device for a power boiler feedwater system according to claim 1, characterized in that, The PID parameter tuning module also receives feedwater temperature signal and steam drum pressure signal respectively, and the output terminal of the PID parameter tuning module is electrically connected to the control input terminal of the frequency converter.

6. The multi-parameter adaptive control device for a power boiler feedwater system according to claim 1, characterized in that, The embedded intelligent controller module also includes a fault diagnosis and safety protection unit. The input terminal of the fault diagnosis and safety protection unit is electrically connected to the data preprocessing unit, and the output terminal of the fault diagnosis and safety protection unit is electrically connected to the multi-parameter fusion adaptive PID control unit.

7. A multi-parameter adaptive control device for a power boiler feedwater system according to claim 6, characterized in that, The embedded intelligent controller module also includes a control mode management unit, which is electrically connected to the fault diagnosis and safety protection unit, the multi-parameter fusion adaptive PID control unit, and the control input terminal of the frequency converter.

8. A multi-parameter adaptive control device for a power boiler feedwater system according to claim 1, characterized in that, The embedded intelligent controller module further includes a storage unit and a runtime cache unit. The storage unit is electrically connected to the main control microprocessor, and the runtime cache unit is electrically connected to the main control microprocessor.

9. A water supply system, characterized in that, Includes the apparatus as described in claim 1.

10. A multi-parameter adaptive control method for a power boiler feedwater system, characterized in that, Based on the device described in claim 1, it includes: Collect the boiler feedwater system's drum liquid level signal, feedwater flow signal, steam flow signal, feedwater pressure signal, drum pressure signal, and feedwater temperature signal; The collected operating signals are subjected to signal conditioning, analog-to-digital conversion and data preprocessing to obtain the corresponding multi-parameter operating data; Feedforward compensation is performed on the steam drum liquid level signal based on the water flow signal and steam flow signal to obtain the corrected water level deviation signal; Based on the corrected water level deviation signal, the deviation change rate, and the comprehensive operating parameters formed by the feedwater temperature signal and the steam drum pressure signal, the PID control parameters are tuned and the feedwater control signal is generated. The water supply control signal is output to the frequency converter, which adjusts the speed of the water supply pump motor. Anomaly detection is performed on the multi-parameter operating data, and the multi-parameter adaptive control mode, single-impulse control mode, or manual control mode is switched according to the anomaly detection results.

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