Electric steam and electricity drive boiler water supply system and water supply pressure self-adaptive control method

Abstract

The invention discloses a steam and electricity combined drive boiler water supply system and a water supply pressure self-adaptive control method, and relates to the technical field of boiler water supply regulation. The steam and electricity combined drive boiler water supply system comprises a power driving module, a monitoring data module, a pressure analysis module, a dynamic regulation module and a fault processing module; the power driving module provides a power source for driving the water feeding pump; the monitoring data module is used for collecting operation parameters and providing operation data for the pressure analysis module; the pressure analysis module is used for analyzing to obtain PID parameters according to the operation data of the monitoring data module; the dynamic adjusting module is used for adjusting the water supply system according to the PID parameters; and the fault processing module is used for monitoring the operation condition of the driving equipment, judging the working state of the driving equipment, realizing steam-electricity combined driving, effectively utilizing waste heat, reducing the dependence on electric power and reducing the total energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler feed water regulation, and in particular to a steam-electricity coupled drive boiler feed water system and a feed water pressure adaptive control method. Background Art

[0002] As one of the key equipment for thermal power generation or cogeneration, the power consumption and operating efficiency of the boiler feed pump directly affect the energy efficiency of the entire power generation or cogeneration system. With the continuous improvement of the national energy conservation and carbon reduction requirements, thermal power or cogeneration units pay more and more attention to recovering the low-pressure steam discharged by the power generation turbine. For this reason, quite a number of units have adopted steam-driven induced draft fan exhaust steam heating technology. However, the existing units that have been put into production generally have a phenomenon of reduced steam flow of small turbines when running at low load, and there is a lack of effective means to adjust the steam intake.

[0003] In addition, seasonal heat load and day and night heat load fluctuations make the adjustment of working conditions complicated; in the gas boiler system, the boiler feed water pump system is one of the key systems to ensure boiler water supply, and its feed water flow and pressure are key parameters affecting the precise control of boiler feed water flow and drum water level;

[0004] In order to reduce the energy consumption of the feedwater pump and achieve more efficient water pressure control, open-loop control is adopted in the prior art. The feedwater pump is mainly driven by an electric motor and an auxiliary driven by a small steam turbine. The electric motor is remotely controlled and operated through the existing DCS control system. Problems exist in actual operation: the feedwater pump pressure is not designed with an automatic control function, and the feedwater pump is variable frequency speed regulation. The operating personnel can only adjust the feedwater pump pressure based on experience, which is labor-intensive and prone to fatigue of the monitoring panel. It is very easy to have overshoot, undershoot, untimely adjustment and other phenomena, which affect the stable operation of the unit;

[0005] The patent document with the authorization announcement number CN114483552A discloses a control method for a steam-electric dual-drive feed water pump system, which includes a feed water pump, a motor, an overrunning clutch, a steam turbine, an inlet steam regulating valve, and a main steam valve. The motor is connected to the feed water pump, the overrunning clutch is connected to the feed water pump, the steam turbine is connected to the overrunning clutch, and the inlet steam regulating valve and the main steam valve are respectively connected to the steam turbine. For the control method used in this system, when the system starts, the motor starts and the steam turbine shuts down. The motor drives the feed water pump to the rated output power. Then the steam turbine starts and its speed is increased to the rated speed of the motor. The feed water pump is switched from being driven by the motor to being driven by the steam turbine. At this time, the motor operates at the critical point of power generation and electromotion. When the system stops, the feed water pump is switched from being driven by the steam turbine to being driven by the motor, and then the steam turbine is stopped, and then the motor is stopped to stop the operation of the feed water pump. When the steam turbine fails, the feed water pump will also be switched to be driven by the motor and the steam turbine will be stopped. During the start-up process of the steam turbine, warm-up needs to be carried out first. After the warm-up is completed, the speed is increased to the rated speed of the motor to complete the drive switching. When the system stops, the steam turbine first reduces the speed to the rated speed of the motor, then performs the drive switching, and then stops the steam turbine and the motor. This control method can achieve flexible drive switching between the steam turbine and the motor for the feed water pump to achieve the purpose of reducing energy consumption and ensuring the stable operation of the system;

[0006] However, the above method has relatively low control accuracy. It is only based on start-stop and switching logic, lacking a fine control algorithm and full consideration of the system's dynamic characteristics, fault modes, and energy consumption optimization; lacking self-adaptive ability and identification and adjustment of system parameters, and no system stability analysis is carried out. Therefore, the control accuracy is not high, the response speed is slow, and the stability is poor, making it difficult to cope with various working conditions and disturbances. Summary of the Invention

[0007] The purpose of the present invention is to provide a steam-electric combined drive boiler feed water system and a feed water pressure self-adaptive control method to solve the problems raised in the prior art.

[0008] To solve the above technical problems, the present invention provides the following technical solutions: A steam-electric combined drive boiler feed water system includes a power drive module, a monitoring data module, a pressure analysis module, a dynamic adjustment module, and a fault handling module;

[0009] Power drive module: Provides the power source for driving the feed water pump;

[0010] Monitoring data module: Collects operating parameters and provides operating data for the pressure analysis module;

[0011] Pressure analysis module: Analyzes and obtains PID parameters based on the operating data of the monitoring data module;

[0012] Dynamic adjustment module: Adjusts the feed water system according to the PID parameters;

[0013] Fault handling module: Monitor the operation of the drive device and determine the working status of the drive device;

[0014] The power drive module is connected to the monitoring data module, the dynamic adjustment module, and the fault handling module;

[0015] The monitoring data module is connected to the pressure analysis module;

[0016] The pressure analysis module is connected to the dynamic adjustment module.

[0017] Furthermore, the power drive module includes a motor unit, a small steam turbine unit, an overrunning clutch unit, and a fuse unit:

[0018] Motor unit: The motor 2-7 provides the initial power to drive the feed water pump 2-8;

[0019] Small steam turbine unit: The outlet of the heating steam main pipe is connected to the steam inlet of the small steam turbine 2-1. When the feed water pump 2-8 reaches the rated output, the small steam turbine 2-1 starts to operate and drives the feed water pump 2-8 to provide auxiliary operation;

[0020] Overrunning clutch unit: The overrunning clutch 2-3 is the component that realizes seamless switching between the motor 2-7 and the small steam turbine 2-1. The small steam turbine 2-1 is connected to the motor 2-7 through the overrunning clutch 2-3. When the speed of the small steam turbine exceeds the speed of the motor, the overrunning clutch will automatically engage, so that the motor and the small steam turbine drive the feed water pump at the same time;

[0021] Fuse unit: The fuse, as a protection component, is located on the power supply lines of the motor 2-7 and the small steam turbine 2-1. When the current exceeds the set value, the fuse will quickly blow, thus cutting off the power supply;

[0022] The motor provides the initial power and handles low-load operation, while the small steam turbine provides auxiliary operation, thereby reducing the load on the motor and improving the overall energy efficiency;

[0023] The design of the fuse ensures the safety of the system under abnormal working conditions and avoids potential equipment damage and shutdown risks;

[0024] Fully utilize the advantages of the two power sources. The motor provides reliable reference power, while the small steam turbine utilizes waste heat, thereby reducing power consumption and improving the environmental footprint of the system. Using a pure electric system would lack the energy-saving advantage of waste heat utilization, and using a pure steam drive system may have a slow response to rapid load changes. Compared with the traditional system, this hybrid method can reduce energy consumption in the steam-electric combined drive boiler feed water system;

[0025] The overrunning clutch is a key component for seamless switching between the motor and the small steam turbine driver. When the speed of the small steam turbine exceeds that of the motor, the overrunning clutch automatically engages, enabling the small steam turbine to drive the feed water pump. The overrunning clutch ensures that the small steam turbine provides assistance only when it can function effectively, preventing it from becoming a drag on the system during low efficiency periods. Direct coupling without using a clutch would force the small steam turbine to operate continuously, potentially reducing efficiency under load conditions. The application of the overrunning clutch enables a smooth transition between power sources, minimizing component stress and maximizing energy efficiency.

[0026] Furthermore, the monitoring data module includes a pressure transmitter unit:

[0027] Pressure transmitter unit: The pressure transmitter 3-1 is installed on the outlet pipeline of the feed water pump to monitor the pressure value of the outlet pressure and upload the pressure value to the pressure analysis module. The pressure transmitter 2-2 is used to monitor the pressure of the feed water system;

[0028] The pressure transmitter provides real-time feedback of the pressure, enabling the controller to make adjustments to maintain the required pressure setpoint. Accurate pressure measurement is crucial for effective closed-loop control.

[0029] Furthermore, the pressure analysis module includes a fuzzy adaptive PID control algorithm unit:

[0030] Fuzzy adaptive PID control algorithm unit: Preset the pressure setpoint of the outlet pressure, obtain the pressure value of the outlet pressure in the monitoring data module, calculate the pressure deviation value and the deviation change rate of the outlet pressure, dynamically adjust the PID control parameters through fuzzy logic, and input the PID control parameters into the dynamic adjustment module;

[0031] The fuzzy logic system is used to adjust the PID parameters in real-time according to the pressure deviation and the change rate, providing robust and adaptive control. Fuzzy logic is good at dealing with non-linear system behavior and uncertainties, making it an ideal choice for adapting the PID controller to changing operating conditions and disturbances. The PID controller provides precise and stable control. A traditional PID controller without fuzzy logic adaptation is difficult to maintain optimal performance under various operating conditions encountered in the boiler feed water system. Compared with a system with fixed PID parameters, fuzzy PID control has higher control accuracy, faster response time, and higher stability.

[0032] Furthermore, the dynamic adjustment module includes a motor adjustment unit and a small steam turbine adjustment unit;

[0033] Motor adjustment unit: The motor PID controller 2-4 dynamically adjusts the speed of the motor by regulating the variable voltage variable frequency (VVVF) converter according to the PID control parameters;

[0034] Mini steam turbine adjustment unit: The mini steam turbine PID controller 1-2 adjusts the opening of the steam inlet control valve 1-3 of the mini steam turbine according to the PID control parameters to control the steam flow rate flowing into the mini steam turbine, and further adjusts the power output of the mini steam turbine.

[0035] The steam inlet control valve controls the steam flow rate flowing into the mini steam turbine, allowing for precise adjustment of the power output of the mini steam turbine according to system requirements. Its precise control of the steam flow rate is crucial for optimizing the performance of the mini steam turbine and matching its output with system requirements.

[0036] Furthermore, the fault handling module monitors the operating conditions of the drive equipment and judges the working state of the drive equipment, including the following:

[0037] When a fault occurs in the mini steam turbine 2-1, the mini steam turbine PID controller 1-2 immediately stops the mini steam turbine and automatically disengages the overrunning clutch 2-3, and the feed water pump 2-8 will be continuously driven by the motor 2-7.

[0038] To better implement the above system, a self-adaptive control method for the steam-electricity combined drive boiler feed water pressure is also proposed. The method includes:

[0039] Step S100: Start the motor to drive the feed water pump, monitor the output value of the feed water pump, and determine the start time of the mini steam turbine.

[0040] Step S200: Collect operation parameters and provide operation data for the pressure analysis module.

[0041] Step S300: Analyze the operation data of the monitoring data module to obtain the PID parameters.

[0042] Step S400: Adjust the feed water system according to the PID parameters.

[0043] Step S500: Monitor the operation conditions of the drive equipment. When a fault occurs in the mini steam turbine, the mini steam turbine PID controller immediately stops the mini steam turbine and automatically disengages the overrunning clutch, and the feed water pump will be continuously driven by the motor.

[0044] Furthermore, step S100 includes the following steps:

[0045] Step S101: Obtain the output value of the feed water pump. When the output value reaches the rated output, the mini steam turbine starts.

[0046] Step S102: Monitor the speed of the motor and the speed of the mini steam turbine. When the speed of the mini steam turbine exceeds the speed of the motor, the overrunning clutch will automatically engage, so that the motor and the mini steam turbine drive the feed water pump at the same time.

[0047] Gradually opening the regulating valve can enable the steam turbine to gradually enter the working state, avoid excessive load suddenly acting on the unit, reduce the impact on the equipment during the startup process, and improve the smoothness of startup;

[0048] By monitoring the speed of the small steam turbine, when its speed exceeds that of the motor, the overrunning clutch is automatically engaged, which enables seamless connection between the drives of the small steam turbine and the motor, avoids the uncertainties that may be brought by manual operation, and effectively improves the operating efficiency;

[0049] Once the speed of the small steam turbine exceeds that of the motor, the system will automatically start the steam-electric combined drive mode, which can not only utilize the power of the small steam turbine but also be assisted by the motor drive, improving the overall operating efficiency and reliability of the system. The coordinated work between the small steam turbine and the motor can better share the load, making the overall system more efficient.

[0050] Further, step S300 includes the following steps:

[0051] Step S301: Preset the pressure set value of the outlet pressure, obtain the pressure value of the outlet pressure in the monitoring data module, and calculate the pressure deviation value and deviation change rate of the outlet pressure;

[0052] Step S302: Dynamically adjust the PID control parameters through fuzzy logic and input the PID control parameters into the dynamic adjustment module;

[0053] By using a pressure transmitter to continuously monitor the outlet pressure of the boiler feed pump, and dynamically adjusting the PID control parameters according to the pressure deviation and change rate, the system can quickly respond during load fluctuations, maintain stable operation, avoid violent pressure fluctuations, ensure the stability of boiler water supply. Dynamically adjusting the PID parameters through fuzzy logic can accurately adapt to different working conditions, optimize the adjustment accuracy, reduce errors caused by human factors, and improve the system response speed and stability;

[0054] This method can automatically adjust the system according to the PID control algorithm without manual intervention, improving the accuracy and reaction speed of system control.

[0055] Further, step S400 includes the following steps:

[0056] Step S401: Obtain the adjustment parameters of the motor PID controller and the adjustment parameters of the small steam turbine PID controller corresponding to the PID control parameters;

[0057] Step S402: The motor PID controller dynamically adjusts the speed of the motor by adjusting the frequency converter according to the adjustment parameters of the motor PID controller. The small steam turbine PID controller adjusts the opening of the steam inlet control valve of the small steam turbine according to the adjustment parameters of the small steam turbine PID controller to control the steam flow rate flowing into the small steam turbine, and then adjusts the power output of the small steam turbine;

[0058] By separately obtaining the PID adjustment parameters of the motor and the small steam turbine, the system can more accurately adjust the operating states of various drive modes. By dynamically adjusting the speed through the frequency converter, the system can quickly respond to pressure changes when the load changes, reduce pressure fluctuations, improve the stability of water supply. By controlling the steam flow rate through the steam inlet control valve, the power output of the small steam turbine is accurately adjusted to achieve a more stable dynamic adjustment;

[0059] By optimizing the steam flow rate adjustment of the small steam turbine, steam waste is avoided, and the overall thermal efficiency of the boiler is improved. Combining the dynamic adjustment of the motor speed by the frequency converter and the steam flow rate adjustment of the small steam turbine, the system can automatically adjust according to the load demand of the boiler, avoiding unstable water supply caused by severe pressure fluctuations.

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows: The adaptive fuzzy PID control system greatly improves the accuracy and stability of the feed water pressure control. By dynamically adjusting the PID parameters according to real-time conditions, the system can effectively compensate for nonlinearity and interference, thereby achieving a more stable and reliable operation; The control system based on fuzzy logic can respond faster to pressure fluctuations and load changes. This fast response can ensure that the system maintains a stable pressure even under harsh operating conditions; The dual-drive system with an automatic switching function can provide redundancy to ensure continuous operation even when the steam turbine fails; The overrunning clutch can prevent the small steam turbine from dragging down the system when it is not needed, thereby further improving the reliability. The steam-electric combined drive system can effectively utilize waste heat, reduce the dependence on electricity, and lower the overall energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a schematic flow chart of a steam-electric combined drive boiler feed water system of the present invention;

[0062] Figure 2 It is a schematic flow chart of a steam-electric combined drive boiler feed water pressure adaptive control method of the present invention;

[0063] Figure 3 It is a working principle diagram of a pressure analysis module in a steam-electric combined drive boiler feed water system of the present invention;

[0064] Figure 4 It is a schematic diagram of the main circuit of the feed water pump in a steam-electric combined drive boiler feed water system of the present invention;

[0065] Figure 5 This is a schematic flowchart of the pressure analysis module in a steam - electricity combined - drive boiler feed - water system of the present invention. Specific embodiments

[0066] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0067] Please refer to Figures 1 - 5 , the present invention provides a technical solution: a steam - electricity combined - drive boiler feed - water system, the system includes a power drive module, a monitoring data module, a pressure analysis module, a dynamic adjustment module, and a fault handling module;

[0068] Power drive module: provides the power source for driving the feed water pump;

[0069] Among them, the power drive module includes a motor unit, a small steam turbine unit, an overrunning clutch unit, and a fuse unit:

[0070] Motor unit: The motor 2 - 7 provides the initial power to drive the feed water pump 2 - 8;

[0071] Small steam turbine unit: The outlet of the heating steam main pipe is connected to the steam inlet of the small steam turbine 2 - 1. When the feed water pump 2 - 8 reaches the rated output, the small steam turbine 2 - 1 starts to operate, driving the feed water pump 2 - 8 to provide auxiliary operation;

[0072] Overrunning clutch unit: The overrunning clutch 2 - 3 is an element that realizes seamless switching between the motor 2 - 7 and the small steam turbine 2 - 1. The small steam turbine 2 - 1 is connected to the motor 2 - 7 through the overrunning clutch 2 - 3. When the rotational speed of the small steam turbine exceeds that of the motor, the overrunning clutch will automatically engage, so that both the motor and the small steam turbine drive the feed water pump simultaneously;

[0073] Fuse unit: The fuse, as a protection element, is located on the power supply lines of the motor 2 - 7 and the small steam turbine 2 - 1. When the current exceeds the set value, the fuse will quickly blow, thus cutting off the power supply;

[0074] For example Figure 4 As shown, the input ends of the four fuses FU are respectively connected to the neutral line N and the three - phase AC power input ends L1, L2, and L3;

[0075] The output ends of the fuses FU in L1, L2, and L3 are respectively connected to the input ends 1, 3, and 5 of the circuit breaker QF;

[0076] The output terminals of the circuit breakers QF in L1, L2, and L3 are respectively connected to the input terminals 2, 4, and 6 of the variable frequency drive VVVF;

[0077] The output terminals of the variable frequency drive VVVF in L1, L2, and L3 are respectively connected to the input terminals 1, 3, and 5 of the thermal relay;

[0078] The output terminals 2, 4, and 6 of the thermal relay in L1, L2, and L3 are connected to the three-phase input terminals U1, V1, and W1 of the motor M1 in the feed water pump M1;

[0079] The PE terminal of the motor M1 in the feed water pump M1 is grounded.

[0080] Monitoring data module: Collects operating parameters and provides operating data for the pressure analysis module;

[0081] Among them, the monitoring data module includes a pressure transmitter unit:

[0082] Pressure transmitter unit: The pressure transmitter 3-1 is installed on the outlet pipeline of the feed water pump to monitor the pressure value of the outlet pressure and upload the pressure value to the pressure analysis module. The pressure transmitter 2-2 is used to monitor the pressure of the feed water system.

[0083] Pressure analysis module: Analyzes and obtains PID parameters based on the operating data of the monitoring data module;

[0084] Among them, the pressure analysis module includes a fuzzy adaptive PID control algorithm unit:

[0085] Fuzzy adaptive PID control algorithm unit: Presets the pressure set value of the outlet pressure, obtains the pressure value of the outlet pressure in the monitoring data module, calculates the pressure deviation value and deviation change rate of the outlet pressure, dynamically adjusts the PID control parameters through fuzzy logic, and inputs the PID control parameters into the dynamic adjustment module.

[0086] Dynamic adjustment module: Adjusts the feed water system according to the PID parameters;

[0087] Among them, the dynamic adjustment module includes a motor adjustment unit and a small steam turbine adjustment unit;

[0088] Motor adjustment unit: The motor PID controller 2-4 dynamically adjusts the speed of the motor by adjusting the variable frequency drive VVVF according to the PID control parameters;

[0089] Small steam turbine adjustment unit: The small steam turbine PID controller 1-2 adjusts the opening of the steam inlet regulating valve 1-3 of the small steam turbine according to the PID control parameters to control the steam flow rate flowing into the small steam turbine, and then adjusts the power output of the small steam turbine;

[0090] For example Figure 5As shown, a pressure set value is received. Through a subtractor, the deviation e between the current pressure and the set pressure is calculated;

[0091] The deviation e and its rate of change de / dt are sent to a fuzzification module to convert the continuous values into fuzzy linguistic variables. Fuzzy inference makes decisions based on a fuzzy rule base to determine a suitable control strategy;

[0092] Defuzzification converts the fuzzy control output back to a specific value, such as ΔK p 、ΔK i 、ΔK d , and the result after defuzzification is sent to a PID controller for precisely adjusting the output value.

[0093] The pressure sensor detects the pressure in real time and feeds it back to the PID controller. The control quantity calculated by the PID controller acts on the steam - electric linkage driven feed water pump.

[0094] Fault handling module: Monitors the operating conditions of the driving equipment and judges the working state of the driving equipment;

[0095] Among them, the fault handling module monitors the operating conditions of the driving equipment and judges the working state of the driving equipment, including the following:

[0096] When the small steam turbine 2 - 1 fails, the small steam turbine PID controller 1 - 2 immediately stops the small steam turbine and automatically disengages the overrunning clutch 2 - 3, and the feed water pump 2 - 8 will be continuously driven by the motor 2 - 7;

[0097] For example Figure 1 As shown, the heating steam main pipe is connected to the small steam turbine PID controllers 1 - 2 and 1 - 1;

[0098] The small steam turbine PID controller 1 - 2 is connected to the pressure transmitter 2 - 2, the pressure transmitter 3 - 1, and the steam inlet regulating valve 1 - 3;

[0099] The steam inlet regulating valve 1 - 3 is connected to the small steam turbine 2 - 1, the temperature indicator 1 - 7, the electric actuator 1 - 4. The electric actuator 1 - 4 is connected to the flow regulating valve 1 - 6 and the pressure regulating valve 1 - 5;

[0100] The small steam turbine 2 - 1 is connected to the temperature indicator 1 - 9, the pressure indicator 1 - 8, the low - pressure deaerator heating steam main pipe, and the overrunning clutch 2 - 3;

[0101] The overrunning clutch 2 - 3 is connected to the motor PID controller 2 - 4;

[0102] The motor PID controller 2 - 4 is connected to the motor 2 - 7 and the electric actuator 2 - 6

[0103] The electric actuator 2 - 6 is connected to the speed regulating valve 2 - 5

[0104] The motor 2-7 is connected to the feed water pump 2-8;

[0105] The water pump 2-8 is connected to the pressure transmitter 3-1 and the pressure indicator 2-9.

[0106] In order to better implement the above system, a steam-electric combined drive boiler feed water pressure adaptive control method is also proposed. The method includes:

[0107] Step S100: Start the motor to drive the feed water pump, monitor the output value of the feed water pump, and determine the starting time of the small steam turbine;

[0108] Among them, step S100 includes the following steps:

[0109] Step S101: Obtain the output value of the feed water pump. When the output value reaches the rated output, the small steam turbine starts;

[0110] Step S102: Monitor the rotational speed of the motor and the rotational speed of the small steam turbine. When the rotational speed of the small steam turbine exceeds the rotational speed of the motor, the overrunning clutch will automatically engage, so that the motor and the small steam turbine drive the feed water pump simultaneously.

[0111] For example, the motor starts, drives the feed water pump to the rated output power, detects the outlet pressure to ensure the normal operation of the feed water pump. After the motor runs, the small steam turbine gradually starts. According to the pressure feedback, the steam inlet regulating valve is adjusted to maintain the set back pressure value. When the rotational speed of the small steam turbine increases and exceeds the rotational speed of the motor, the overrunning clutch automatically engages.

[0112] Step S200: Collect operation parameters and provide operation data for the pressure analysis module;

[0113] Step S300: Analyze and obtain the PID parameters according to the operation data of the monitoring data module;

[0114] Among them, step S300 includes the following steps:

[0115] Step S301: Preset the pressure set value of the outlet pressure, obtain the pressure value of the outlet pressure in the monitoring data module, and calculate the pressure deviation value and the deviation change rate of the outlet pressure;

[0116] Step S302: Dynamically adjust the PID control parameters through fuzzy logic and input the PID control parameters into the dynamic adjustment module;

[0117] For example Figure 3As described above, the first pin of the DCS controller is used to receive the pressure set value input by the interface. The second pin of the DCS controller is connected to the variable frequency drive VVVF through Modbus and Ethernet / IP networks. The third pin of the DCS controller is used to receive the pressure feedback value and is connected to the pressure sensor B1;

[0118] The PID controller calculates the PID control parameters, including proportional control:

[0119] P = K p ×E;

[0120] Integral control:

[0121] I = K i ×∫Edt;

[0122] Integral control:

[0123]

[0124] Among them, P is the proportional control output, K p is the proportional gain, and E is the difference between the pressure set value and the outlet pressure; I is the integral control output, K i is the integral gain, and ∫Edt is the sum of the errors accumulated over time; D is the derivative control output, K d is the derivative gain, is the rate of change of the error over time;

[0125] The outlet pressure set value is set through the interface. The pressure set value is in the range of 12.5 Mpa - 13.5 Mpa. The pressure transmitter feeds back the current outlet pressure through an analog signal. This signal is collected by the AI port of the DCS interface board and transmitted to the DCS controller. The DCS controller is connected to the variable frequency drive through a fieldbus (such as Modbus and Ethernet / IP) and sets the frequency set value of the variable frequency drive;

[0126] When the outlet pressure is less than the set value, the motor starts and drives the feed water pump to the rated output power. At this time, the pressure value of the current outlet pressure is obtained through the pressure transmitter. If the outlet pressure is less than the set value, the steam inlet control valve is fully open;

[0127] The pressure deviation value and the deviation change rate are inferred according to the fuzzy rules. Among them, when the pressure deviation value is negative large and the deviation change rate is negative small, the PID control parameter is positive large; when the pressure deviation value is negative small and the deviation change rate is zero, the PID control parameter is positive small;

[0128] When the outlet pressure is greater than the set value, reasoning is carried out according to fuzzy rules. Among them, when the pressure deviation value is large positive and the deviation change rate is small positive, the PID control parameter is large negative; when the pressure deviation value is small positive and the deviation change rate is zero, the PID control parameter is small negative.

[0129] Step S400: Adjust the feed water system according to the PID parameters;

[0130] Among them, step S400 includes the following steps:

[0131] Step S401: Obtain the adjustment parameters of the motor PID controller and the adjustment parameters of the small steam turbine PID controller corresponding to the PID control parameters;

[0132] Step S402: The motor PID controller dynamically adjusts the speed of the motor by adjusting the frequency converter according to the adjustment parameters of the motor PID controller. The small steam turbine PID controller adjusts the opening of the steam inlet regulating valve of the small steam turbine according to the adjustment parameters of the small steam turbine PID controller to control the steam flow rate flowing into the small steam turbine, and then adjusts the power output of the small steam turbine;

[0133] For example, when the PID control parameter is large positive or small positive, the motor PID controller adjusts the output frequency of the motor through the frequency converter to increase the flow rate, and the small steam turbine PID controller continuously adjusts the opening of the steam inlet valve according to the new pressure deviation;

[0134] When the PID control parameter is large negative or small negative, the motor PID controller reduces the speed of the motor through the frequency converter, and the small steam turbine PID controller reduces the opening of the steam inlet valve according to the new pressure deviation to reduce the steam flow rate entering the small steam turbine;

[0135] If the speed of the small steam turbine is lower than the speed of the motor, the overrunning clutch remains engaged, and the system operates with dual steam and electric drive. If the load of the small steam turbine is too low, the system can automatically switch to single motor drive.

[0136] Step S500: Monitor the operation of the drive device. When a failure occurs in the small steam turbine, the small steam turbine PID controller immediately stops the small steam turbine and automatically disengages the overrunning clutch, and the feed water pump will continue to be driven by the motor.

[0137] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, in any respect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

Claims

1. A steam-electric combined drive boiler feed water system, characterized in that, The system includes a power drive module, a monitoring data module, a pressure analysis module, a dynamic adjustment module, and a fault handling module; The power drive module: provides the power source for driving the feed water pump; The monitoring data module: collects operation parameters and provides operation data for the pressure analysis module; The pressure analysis module: analyzes the operation data of the monitoring data module to obtain PID parameters; The dynamic adjustment module: adjusts the feed water system according to the PID parameters; The fault handling module: monitors the operation of the driving equipment and judges the working state of the driving equipment; The power drive module is connected to the monitoring data module, the dynamic adjustment module, and the fault handling module; The monitoring data module is connected to the pressure analysis module; The pressure analysis module is connected to the dynamic adjustment module.

2. The steam-electric combined drive boiler feed water system according to claim 1, wherein The power drive module includes a motor unit, a small steam turbine unit, an overrunning clutch unit, and a fuse unit: The motor unit: The motor 2-7 provides the initial power to drive the feed water pump 2-8; The small steam turbine unit: The outlet of the heating steam main pipe is connected to the steam inlet of the small steam turbine 2-1. When the feed water pump 2-8 reaches the rated output, the small steam turbine 2-1 starts to operate and drives the feed water pump 2-8 to provide auxiliary operation; The overrunning clutch unit: The overrunning clutch 2-3 is an element that realizes seamless switching between the motor 2-7 and the small steam turbine 2-1. The small steam turbine 2-1 is connected to the motor 2-7 through the overrunning clutch 2-3. When the speed of the small steam turbine exceeds the speed of the motor, the overrunning clutch will automatically engage, so that the motor and the small steam turbine drive the feed water pump at the same time; The fuse unit: The fuse, as a protection element, is located on the power supply lines of the motor 2-7 and the small steam turbine 2-1. When the current exceeds the set value, the fuse will quickly blow, thus cutting off the power supply.

3. A method for a steam-electric combined drive boiler feed water system according to claim 2, characterized in that The monitoring data module includes a pressure transmitter unit: The pressure transmitter unit: The pressure transmitter 3-1 is installed on the outlet pipeline of the feed water pump to monitor the pressure value of the outlet pressure and upload the pressure value to the pressure analysis module. The pressure transmitter 2-2 is used to monitor the pressure of the feed water system.

4. The steam-electric combined drive boiler feed water system according to claim 3, characterized in that, The pressure analysis module includes a fuzzy adaptive PID control algorithm unit: The fuzzy adaptive PID control algorithm unit: Presets the pressure set value of the outlet pressure, obtains the pressure value of the outlet pressure in the monitoring data module, calculates the pressure deviation value and the deviation change rate of the outlet pressure, dynamically adjusts the PID control parameters through fuzzy logic, and inputs the PID control parameters into the dynamic adjustment module.

5. The steam-electric combined drive boiler feed water system according to claim 4, characterized in that, The dynamic adjustment module includes a motor adjustment unit and a small steam turbine adjustment unit; The motor adjustment unit: The motor PID controller 2-4 dynamically adjusts the speed of the motor by adjusting the frequency converter VVVF according to the PID control parameters; The small steam turbine adjustment unit: The small steam turbine PID controller 1-2 adjusts the opening of the steam inlet control valve 1-3 of the small steam turbine according to the PID control parameters to control the steam flow rate flowing into the small steam turbine, and then adjusts the power output of the small steam turbine.

6. The steam-electric combined drive boiler feed water system according to claim 5, characterized in that, The fault handling module monitors the operation of the drive device and judges the working state of the drive device, including the following: When the small steam turbine 2-1 fails, the small steam turbine PID controller 1-2 immediately stops the small steam turbine and automatically disengages the overrunning clutch 2-3, and the feed water pump 2-8 will continue to be driven by the motor 2-7.

7. A method for adaptively controlling the feed water pressure of a steam-electric combined drive boiler, which is used to implement the steam-electric combined drive boiler feed water system described in any one of claims 1-6, characterized in that, The method includes: Step S100: Start the motor to drive the feed water pump, monitor the output value of the feed water pump, and determine the starting time of the small steam turbine; Step S200: Collect operation parameters and provide operation data for the pressure analysis module; Step S300: Analyze and obtain the PID parameters according to the operation data of the monitoring data module; Step S400: Adjust the feed water system according to the PID parameters; Step S500: Monitor the operation of the drive device. When the small steam turbine fails, the small steam turbine PID controller immediately stops the small steam turbine and automatically disengages the overrunning clutch, and the feed water pump will continue to be driven by the motor.

8. A steam-electric combined drive boiler feed water pressure adaptive control method according to claim 7, characterized in that The said step S100 includes the following steps: Step S101: Obtain the output value of the feed water pump. When the output value reaches the rated output, the small steam turbine starts; Step S102: Monitor the rotational speed of the motor and the rotational speed of the small steam turbine. When the rotational speed of the small steam turbine exceeds the rotational speed of the motor, the overrunning clutch will automatically engage, so that the motor and the small steam turbine drive the feed water pump at the same time.

9. The self-adaptive control method for the feed water pressure of a steam-electric combined drive boiler according to claim 8, wherein The said step S300 includes the following steps: Step S301: Preset the pressure set value of the outlet pressure, obtain the pressure value of the outlet pressure in the monitoring data module, and calculate the pressure deviation value and deviation change rate of the outlet pressure; Step S302: Dynamically adjust the PID control parameters through fuzzy logic and input the PID control parameters into the dynamic adjustment module.

10. The adaptive control method for the feed water pressure of a steam-electric combined drive boiler according to claim 9, wherein The said step S400 includes the following steps: Step S401: Obtain the adjustment parameters of the motor PID controller and the adjustment parameters of the small steam turbine PID controller corresponding to the PID control parameters; Step S402: The motor PID controller dynamically adjusts the rotational speed of the motor by adjusting the frequency converter according to the adjustment parameters of the motor PID controller. The small steam turbine PID controller adjusts the opening of the steam inlet regulating valve of the small steam turbine according to the adjustment parameters of the small steam turbine PID controller to control the steam flow rate flowing into the small steam turbine, and then adjusts the power output of the small steam turbine.

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