Automatic control method of feed pump

Abstract

The invention provides an automatic control method for a water feeding pump, and relates to the technical field of industrial automation control. Setting a prediction period and a control period; determining a rotating speed demand based on the unit load; establishing a pump efficiency and energy loss model; calculating pump efficiency and energy loss parameters; establishing an optimization function model, and calculating an ideal rotating speed; converting the ideal rotating speed into instruction information and sending the instruction information to an electric actuator to adjust the rotating speed; repeating the steps at the beginning of the next control period to form closed-loop control; dynamic adjustment of the rotating speed of the water feeding pump is achieved by monitoring key parameters in real time and establishing an accurate prediction model and an optimization algorithm, so that the efficiency and the response speed of the system are improved, and the energy loss is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial automation control, and in particular to an automatic control method for a water supply pump. Background Art

[0002] With the continuous improvement of industrial automation level, the control accuracy and efficiency requirements for various industrial equipment are getting higher and higher. In the process of starting, stopping or overhauling the feedwater pump in a thermal power plant, the electric feedwater pump is one of the key equipment, and its operating efficiency directly affects the energy consumption and stability of the entire system. Traditional feedwater pump control systems mostly use fixed speed operation or simple frequency conversion control, which is difficult to adapt to the high-efficiency energy-saving needs under complex working conditions. In addition, due to the long control cycle, the system responds slowly to load changes and cannot adjust the feedwater pump speed in time, affecting the stability and reliability of the system.

[0003] At the same time, in traditional systems, the energy loss of the hydraulic coupling is large, especially when the speed of the water feed pump deviates from the optimal speed; manual adjustment of the speed of the water feed pump requires more manual intervention, which increases the complexity of operation and the possibility of error; because the control strategy is not intelligent enough, the equipment is prone to excessive wear, resulting in increased maintenance costs. Summary of the invention

[0004] The present invention provides an automatic control method for a water supply pump, which realizes dynamic adjustment of the rotation speed of the water supply pump by real-time monitoring of key parameters, establishing an accurate prediction model and an optimization algorithm, thereby improving the efficiency and response speed of the system and reducing energy loss.

[0005] The present invention provides an automatic control method for a water supply pump, comprising:

[0006] Step 1: Obtain key parameters of the water feed pump and hydraulic coupling in real time;

[0007] Step 2: pre-set the prediction period and control period, and the control period is shorter than the prediction period;

[0008] Step 3, matching the unit load with the forecast period, and determining the feedwater pump speed requirement at the end of each forecast period based on the relationship between the unit load and the feedwater pump speed;

[0009] Step 4, pre-establishing a pump efficiency model and a fluid coupling energy loss model;

[0010] Step 5: At the beginning of a control cycle, the current key parameters obtained in step 1 and the speed demand of the next prediction cycle determined in step 3 are correspondingly substituted into the model to obtain the pump efficiency parameters and energy loss parameters of the prediction cycle;

[0011] Step 6: Pre-establish an optimization function model, substitute the pump efficiency parameter and energy loss parameter of the prediction period into the function model for calculation, and determine the ideal speed required from the current moment to the end moment of the prediction period under the condition of minimizing the objective function;

[0012] Step 7, converting the ideal speed into command information and sending it to the electric actuator, and controlling the hydraulic coupling through the electric actuator, thereby adjusting the speed of the water pump to the ideal speed;

[0013] Step 8: Repeat steps 5 to 7 at the beginning of the next control cycle to form an automatic closed-loop control.

[0014] According to an automatic control method for a water supply pump provided by the present invention, in step one, the key parameters of the water supply pump and the hydraulic coupling include: water supply pump motor efficiency, input current, input voltage, fluid density, rated flow, head, maximum speed and minimum speed.

[0015] According to an automatic control method for a water supply pump provided by the present invention, in step 2, the prediction period is the time length for predicting future unit behavior, and the control period is the time interval for adjusting the speed of the water supply pump each time;

[0016] The control period is shorter than the prediction period, and is used to adjust the speed of the water feed pump multiple times within the prediction period to cope with changes in the unit.

[0017] According to an automatic control method for a feedwater pump provided by the present invention, in step three, matching the unit load with the forecast period, and determining the feedwater pump speed requirement at the end of each forecast period based on the relationship between the unit load and the feedwater pump speed includes the following steps:

[0018] Obtain historical unit load data and corresponding feedwater pump speed;

[0019] According to the characteristics of the unit and historical operating data, establish an empirical model of unit load and feedwater pump speed;

[0020] The historical data is classified according to the forecast period, and input into the empirical model accordingly to calculate the feedwater pump speed requirement at the end of each forecast period;

[0021] Perform a rationality check on the calculated speed demand to ensure that the speed demand is within the rated speed range of the feed water pump;

[0022] The feedwater pump speed requirement at the end of each forecast period is recorded and stored for use in subsequent steps.

[0023] According to an automatic control method for a water supply pump provided by the present invention, in step 4, the pre-established pump efficiency model is:

[0024]

[0025] Among them, η is the pump efficiency parameter, ρ is the fluid density, Q is the rated flow rate of the water pump, and H is the head; η m is the motor efficiency, I is the input current, V is the input voltage;

[0026] The pump efficiency parameter η represents the ratio of the effective output power of the feedwater pump to the input electrical power.

[0027] According to an automatic control method for a water supply pump provided by the present invention, in step 4, the energy loss model of the hydraulic coupling is:

[0028] ΔP loss =k(N X -N opt ) 2

[0029] Where ΔP loss is the energy loss parameter, k is the energy loss coefficient, which is used to quantify the relationship between the energy loss of the hydraulic coupling and the degree to which the speed of the feed pump deviates from the speed requirement; N opt is the speed requirement for the next prediction period determined in step 3, N X The ideal speed required to reach the end of the prediction cycle at the current moment;

[0030] The energy loss parameter ΔP loss represents the energy loss of the hydraulic coupling at different ideal speeds, and the energy loss parameter ΔP loss The result carries the unknown ideal speed N X .

[0031] According to an automatic control method for a water supply pump provided by the present invention, in step six, the optimization function model is established as follows:

[0032]

[0033] Among them, J is the optimization objective function value, T p+1 is the next forecast period, T p is the current prediction period; α is a trade-off factor between 0 and 1, which is used to balance two different goals, namely, reducing the energy loss of the hydraulic coupling and improving the efficiency of the feedwater pump;

[0034] The smaller the value of the optimization objective function is, the more efficient the system operation is, the smaller the energy loss of the hydraulic coupling is, and the higher the efficiency of the water feed pump is.

[0035] According to an automatic control method for a water supply pump provided by the present invention, in step six, the process of determining the ideal speed required from the current moment to the end moment of the prediction cycle under the condition of minimizing the objective function is:

[0036] Set the maximum speed and minimum speed of the water supply pump as constraints;

[0037] Calculate several optimization objective function values ​​J by linear programming method;

[0038] Screen and sort several optimization objective function values ​​J to determine the minimum objective function value J min ;

[0039] Based on minimizing the objective function value J min Determine the ideal speed N corresponding to it X .

[0040] According to an automatic control method for a water supply pump provided by the present invention, in step seven, the process of converting the ideal rotation speed into instruction information and sending it to the electric actuator is completed by a PID controller.

[0041] Compared with the prior art, the beneficial effects of this application are:

[0042] 1. By adjusting the speed of the water supply pump in real time to match the actual demand, the water supply flow rate can be controlled more accurately, thereby improving the overall efficiency of the water supply pump system;

[0043] 2. The use of hydraulic coupling energy loss model and optimization algorithm can effectively reduce the energy loss in the hydraulic coupling and further save energy;

[0044] 3. A shorter control cycle is used to adjust the speed of the water supply pump, so that the system can respond quickly to load changes, enhancing the stability and flexibility of the system;

[0045] 4. Through automated control technology, the need for manual intervention is reduced, the operation process is simplified, and the operation difficulty and error rate are reduced;

[0046] 5. By precisely controlling the working state of the water pump, unnecessary wear and overload can be avoided, which helps to extend the service life of the equipment;

[0047] 6. Reduce operating costs and improve economic benefits by improving efficiency and reducing energy consumption;

[0048] 7. Due to the adoption of more sophisticated control strategies, abnormal wear of equipment is reduced, and maintenance frequency and cost are reduced;

[0049] 8. The present invention realizes intelligent management of the system by establishing models and optimizing algorithms, which helps to achieve smarter and more efficient production management;

[0050] In summary, the present invention not only improves efficiency and response speed but also reduces energy consumption and maintenance costs by accurately controlling the operating state of the water supply pump, thus having significant economic and social benefits.

[0051] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0052] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0054] Figure 1 It is a flow chart of an automatic control method for a water supply pump provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0056] Embodiment 1:

[0057] The present invention provides an automatic control method for a water supply pump. Figure 1 ,include:

[0058] Step 1: Obtain key parameters of the water feed pump and hydraulic coupling in real time;

[0059] Step 2: pre-set the prediction period and control period, and the control period is shorter than the prediction period;

[0060] Step 3, matching the unit load with the forecast period, and determining the feedwater pump speed requirement at the end of each forecast period based on the relationship between the unit load and the feedwater pump speed;

[0061] Step 4, pre-establishing a pump efficiency model and a fluid coupling energy loss model;

[0062] Step 5: At the beginning of a control cycle, the current key parameters obtained in step 1 and the speed demand of the next prediction cycle determined in step 3 are correspondingly substituted into the model to obtain the pump efficiency parameters and energy loss parameters of the prediction cycle;

[0063] Step 6: Pre-establish an optimization function model, substitute the pump efficiency parameter and energy loss parameter of the prediction period into the function model for calculation, and determine the ideal speed required from the current moment to the end moment of the prediction period under the condition of minimizing the objective function;

[0064] Step 7: Convert the ideal speed into command information and send it to the electric actuator, and control the hydraulic coupling through the electric actuator to adjust the speed of the water pump to the ideal speed;

[0065] Step 8: Repeat steps 5 to 7 at the beginning of the next control cycle to form an automatic closed-loop control.

[0066] The principle of the above embodiment is: this embodiment obtains the key parameters of the water feed pump and the hydraulic coupling in real time to provide an accurate data basis for subsequent calculation and control; pre-sets the prediction period and the control period, wherein the control period is shorter than the prediction period, so as to adjust the speed of the water feed pump multiple times within the prediction period to better cope with the changes of the unit; matches the unit load with the prediction period, and determines the speed requirement of the water feed pump at the end of each prediction period according to the relationship between the unit load and the speed of the water feed pump, so as to ensure that the speed of the water feed pump can meet the operation requirements of the unit; pre-establishes a pump efficiency model and a hydraulic coupling energy loss model, and at the beginning of the control period, substitutes the current key parameters and the speed requirement of the next prediction period into the model to obtain the pump efficiency parameter and the energy loss parameter, so as to accurately evaluate the operation status of the water feed pump and the hydraulic coupling; then, pre-establishes an optimization function model, substitutes the pump efficiency parameter and the energy loss parameter into the model for calculation, and determines the ideal speed under the condition of minimizing the objective function, thereby realizing the optimization control of the speed of the water feed pump, so that the system improves the efficiency of the water feed pump while reducing the energy loss of the hydraulic coupling;

[0067] Finally, by converting the ideal speed into command information and sending it to the electric actuator, the electric actuator controls the hydraulic coupling's regulation action, adjusts the speed of the water pump to the ideal speed, and repeats the above process at the beginning of the next control cycle, forming an automatic closed-loop control, which continuously adjusts according to the system's operating status to ensure that the system is always in an efficient and stable operating state.

[0068] The beneficial effects of the above embodiment are: by acquiring key parameters in real time, establishing models and optimizing functions, it is possible to achieve accurate control of the speed of the electric water supply pump, thereby improving the operational stability and reliability of the system;

[0069] The optimization function determines the ideal speed by minimizing the objective function, which can reduce the energy loss of the hydraulic coupling and improve the efficiency of the water feed pump, thus achieving efficient operation of the system.

[0070] Automatically adjust the speed of the feedwater pump according to the load changes and forecast cycle of the unit, which can better adapt to different operating conditions and improve the adaptability and flexibility of the system;

[0071] Form an automatic closed-loop control, constantly adjust according to the system's operating status, ensure the system is always in the best operating state, and improve the system's control accuracy and stability;

[0072] Real-time acquisition of key parameters provides accurate data support for system operation and control, helps to discover and solve problems in a timely manner, and improves the maintenance and management level of the system.

[0073] In order to further optimize the above embodiment, in step one, the key parameters of the water feed pump and the hydraulic coupling include: water feed pump motor efficiency, input current, input voltage, fluid density, rated flow, head, maximum speed and minimum speed.

[0074] It should be noted that the efficiency of the water pump motor directly affects the energy efficiency of the entire system; the input current and input voltage can reflect the power consumption of the water pump; the fluid density is crucial to calculating the output power and efficiency of the pump; the rated flow and head are important indicators of the water pump performance, which determine its working capacity under different working conditions; the maximum speed and minimum speed provide limits for the operating range of the water pump to ensure control within a safe and reliable range;

[0075] By acquiring the above key parameters in real time, we can fully understand the operating status of the water feed pump and hydraulic coupling, and provide an accurate data basis for subsequent model establishment and optimization calculations, thereby achieving more precise and efficient automatic control.

[0076] In order to further optimize the above embodiment, in step 2, the prediction period is the time length for predicting the future unit behavior, and the control period is the time interval for each adjustment of the feedwater pump speed;

[0077] The control cycle is smaller than the prediction cycle and is used to adjust the feed water pump speed multiple times within the prediction cycle to cope with changes in the unit.

[0078] It should be noted that the setting of the prediction cycle enables the system to predict the future behavior of the unit to a certain extent, so as to plan the speed demand of the water feed pump in advance and provide guidance for subsequent control operations; and the control cycle is shorter than the prediction cycle, which ensures that the speed of the water feed pump can be adjusted multiple times within the prediction cycle; the advantage of this is that when the unit changes, the system can respond more promptly to avoid unstable system operation or inefficiency due to untimely adjustment; through frequent small adjustments, the speed of the water feed pump can be more accurately adapted to the dynamic changes of the unit, improving the adaptability and reliability of the entire system; at the same time, this multiple adjustment method also reduces the impact and risks that may be caused by a single large adjustment, which helps to extend the service life of the equipment and ensure the safe and stable operation of the system.

[0079] In order to further optimize the above embodiment, in step three, matching the unit load with the forecast period, and determining the feedwater pump speed requirement at the end of each forecast period based on the relationship between the unit load and the feedwater pump speed includes the following steps:

[0080] Obtain historical unit load data and corresponding feedwater pump speed;

[0081] According to the characteristics of the unit and historical operating data, establish an empirical model of unit load and feedwater pump speed;

[0082] The historical data is classified according to the forecast period, and input into the empirical model accordingly to calculate the feedwater pump speed requirement at the end of each forecast period;

[0083] Perform a rationality check on the calculated speed demand to ensure that the speed demand is within the rated speed range of the feed water pump;

[0084] The feedwater pump speed requirement at the end of each forecast period is recorded and stored for use in subsequent steps.

[0085] It should be noted that, first of all, obtaining historical unit load data and the corresponding feedwater pump speed provides a rich data basis for establishing an empirical model; by analyzing these historical data, we can better understand the relationship between unit load and feedwater pump speed, so as to establish a more accurate empirical model; the empirical model is set based on actual conditions, and algorithms such as machine learning can also be selected to achieve prediction functions;

[0086] The historical data is classified according to the forecast period and input into the empirical model for calculation. This can fully take into account the changing characteristics of the unit load in different time periods, so that the calculated feedwater pump speed demand is more in line with the actual situation. At the same time, the calculated speed demand is checked for rationality to ensure that it is within the rated speed range of the feedwater pump. This measure can effectively avoid damage to the equipment due to excessively high or low speed, and ensure the safe and stable operation of the system.

[0087] Finally, the feed water pump speed requirements at the end of each forecast cycle are recorded and stored, which facilitates the use of subsequent steps; this data can be quickly called when needed, improving the operating efficiency of the system and providing a reference for subsequent analysis and optimization.

[0088] In order to further optimize the above embodiment, in step 4, a pump efficiency model is pre-established as follows:

[0089]

[0090] Among them, η is the pump efficiency parameter, ρ is the fluid density, Q is the rated flow rate of the water pump, and H is the head; η m is the motor efficiency, I is the input current, V is the input voltage;

[0091] The pump efficiency parameter η represents the ratio of the effective output power of the feedwater pump to the input electrical power.

[0092] It should be noted that the pump efficiency model can accurately reflect the actual working efficiency of the water supply pump by incorporating key parameters such as fluid density, rated flow rate of the water supply pump, head, motor efficiency, input current and input voltage into the calculation;

[0093] Among them, the pump efficiency parameter represents the ratio of the effective output power of the water feed pump to the input electrical power, which allows us to intuitively understand the energy conversion efficiency of the water feed pump under different working conditions; through the monitoring and analysis of this parameter, we can promptly discover problems in the operation of the water feed pump, such as reduced motor efficiency, abnormal flow or head, etc., so as to take corresponding measures to optimize and adjust; in addition, the establishment of this model also provides a basis for the subsequent optimization function calculation; by substituting the pump efficiency parameter and the hydraulic coupling energy loss parameter into the optimization function model, the optimal control of the water feed pump speed can be achieved, so as to achieve the purpose of improving the overall efficiency of the system and reducing energy consumption.

[0094] In order to further optimize the above embodiment, in step 4, the fluid coupling energy loss model is:

[0095] ΔP loss =k(N X -N opt ) 2

[0096] Where ΔP loss is the energy loss parameter, k is the energy loss coefficient, which is used to quantify the relationship between the energy loss of the hydraulic coupling and the degree to which the speed of the feed pump deviates from the speed requirement; N opt is the speed requirement for the next prediction period determined in step 3, N X The ideal speed required to reach the end of the prediction cycle at the current moment;

[0097] Energy loss parameter ΔP loss Represents the energy loss of the hydraulic coupling at different ideal speeds, and the energy loss parameter ΔP loss The result carries the unknown ideal speed N X .

[0098] It should be noted that the energy loss coefficient quantifies the relationship between the energy loss of the hydraulic coupling and the degree to which the speed of the water feed pump deviates from the speed requirement, and can clearly understand the impact of the change in the speed of the water feed pump on the energy loss. The energy loss coefficient is obtained based on the manufacturing data of the supplier;

[0099] After the speed requirement for the next forecast period is determined, the model can be used to calculate the energy loss parameters at different ideal speeds. Since the energy loss parameter results carry unknown ideal speeds, this provides a target orientation for determining the optimal ideal speed through the optimization function model.

[0100] Although the speed requirement for the next forecast period is known, this requirement is only calculated based on historical data and empirical models, and does not fully consider the actual operating status of the current system and the energy loss of the hydraulic coupling;

[0101] The role of the optimization objective function in the next step is to comprehensively consider the two goals of reducing the energy loss of the hydraulic coupling and improving the efficiency of the water pump. If the speed demand of the next prediction cycle is directly used as the ideal speed, it will lead to a large energy loss of the hydraulic coupling, or the efficiency of the water pump will not reach the optimal state;

[0102] By establishing a pump efficiency model, a hydraulic coupling energy loss model and an optimization function model, and determining the ideal speed based on the condition of minimizing the objective function, it is possible to find an ideal speed that best balances energy loss and pump efficiency under various conditions of the current key parameters and forecast period, thereby achieving efficient operation of the system; rather than simply adopting the pre-calculated speed requirement for the next forecast period.

[0103] In order to further optimize the above embodiment, in step six, an optimization function model is established as follows:

[0104]

[0105] Among them, J is the optimization objective function value, T p+1 is the next forecast period, T p is the current prediction period; α is a trade-off factor between 0 and 1, which is used to balance two different goals, namely, reducing the energy loss of the hydraulic coupling and improving the efficiency of the feedwater pump;

[0106] The smaller the optimization objective function value is, the more efficient the system operation is, the smaller the energy loss of the hydraulic coupling is, and the higher the efficiency of the water feed pump is.

[0107] It should be noted that, firstly, by introducing the trade-off factor, the relative importance between the two objectives of reducing the energy loss of the hydraulic coupling and improving the efficiency of the water supply pump can be flexibly adjusted; according to the actual system operation requirements and performance requirements, the value of the trade-off factor can be dynamically adjusted to achieve the optimal control effect;

[0108] Secondly, the optimization objective function value comprehensively considers the energy loss of the hydraulic coupling and the efficiency of the water supply pump, and is calculated in the form of integration over the time interval, which can comprehensively reflect the operating performance of the system in the entire prediction period; when the optimization objective function value is smaller, it indicates that the system has achieved a better balance in reducing energy loss and improving efficiency, and the operation is more efficient;

[0109] In addition, this optimization function model provides a clear goal orientation for determining the ideal speed. In the process of determining the ideal speed based on minimizing the objective function, various optimization algorithms, such as linear programming methods, can be used to search for the ideal speed that minimizes the optimization objective function value. This ensures that the system is always adjusted in the optimal direction during operation, thereby improving the overall performance and stability of the system.

[0110] In order to further optimize the above embodiment, in step 6, the process of determining the ideal speed required to reach the end time of the prediction cycle from the current time under the condition of minimizing the objective function is as follows:

[0111] Set the maximum speed and minimum speed of the water supply pump as constraints;

[0112] Calculate several optimization objective function values ​​J by linear programming method;

[0113] Screen and sort several optimization objective function values ​​J to determine the minimum objective function value J min ;

[0114] Based on minimizing the objective function value J min Determine the ideal speed N corresponding to it X .

[0115] It should be noted that, firstly, the maximum speed and the minimum speed of the water feed pump are set as constraints to ensure that the safe operating range of the water feed pump will not be exceeded when determining the ideal speed; this helps to protect the equipment, avoid damage to the water feed pump due to excessively high or low speed, and ensure the stable operation of the system;

[0116] Secondly, by calculating several optimization objective function values ​​by linear programming method, the efficiency and accuracy of linear programming can be fully utilized; linear programming is a mature optimization algorithm that can quickly find the optimal solution or approximate optimal solution under given constraints; by calculating multiple optimization objective function values, different possible situations can be comprehensively evaluated to increase the possibility of finding the optimal ideal speed;

[0117] Then, the process of screening and sorting several optimization objective function values ​​and determining the process of minimizing the objective function value can effectively screen out the best solution from many possible results; through sorting, the advantages and disadvantages of different solutions can be clearly compared to ensure that the selected minimized objective function value is the most consistent with the system optimization goal;

[0118] Finally, the ideal speed corresponding to the minimization of the objective function value is determined, and automatic control oriented towards the optimization goal is realized; this ideal speed is determined after comprehensively considering factors such as the energy loss of the hydraulic coupling and the efficiency of the water pump, which can enable the system to reach the optimal operating state when it reaches the end of the prediction cycle at the current moment, thereby improving the overall performance and efficiency of the system.

[0119] In order to further optimize the above embodiment, in step seven, the process of converting the ideal rotation speed into instruction information and sending it to the electric actuator is completed by a PID controller.

[0120] It should be noted that, on the one hand, the PID controller has a wide range of applicability and a mature technical foundation; it can quickly and accurately adjust the output command according to the deviation between the actual speed and the ideal speed through the three links of proportion, integration and differentiation, so that the system can respond quickly and stabilize at the ideal speed state;

[0121] On the other hand, the PID controller can achieve precise control of the speed of the water feed pump; through continuous monitoring and adjustment, it can effectively eliminate various interference factors in the system and ensure that the speed of the water feed pump always remains near the optimal value, thereby improving the stability and reliability of the system;

[0122] In addition, the PID controller also has the characteristic of relatively simple parameter adjustment; according to the characteristics and operation requirements of the actual system, the three parameters of proportion, integration and differentiation can be reasonably adjusted to achieve the best control effect;

[0123] In summary, the use of PID controller to complete the process of converting the ideal speed into command information and sending it to the electric actuator can provide efficient, accurate and reliable guarantee for the automatic control of the electric water pump.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for automatically controlling a water supply pump, characterized in that: The following steps are involved: Step 1: Obtain key parameters of the water feed pump and hydraulic coupling in real time; Step 2: pre-set the prediction period and control period, and the control period is shorter than the prediction period; Step 3, matching the unit load with the forecast period, and determining the feedwater pump speed requirement at the end of each forecast period based on the relationship between the unit load and the feedwater pump speed; Step 4, pre-establishing a pump efficiency model and a fluid coupling energy loss model; Step 5: At the beginning of a control cycle, the current key parameters obtained in step 1 and the speed demand of the next prediction cycle determined in step 3 are correspondingly substituted into the model to obtain the pump efficiency parameters and energy loss parameters of the prediction cycle; Step 6: Pre-establish an optimization function model, substitute the pump efficiency parameter and energy loss parameter of the prediction period into the function model for calculation, and determine the ideal speed required from the current moment to the end moment of the prediction period under the condition of minimizing the objective function; Step 7, converting the ideal speed into command information and sending it to the electric actuator, and controlling the hydraulic coupling through the electric actuator, thereby adjusting the speed of the water pump to the ideal speed; Step 8: Repeat steps 5 to 7 at the beginning of the next control cycle to form an automatic closed-loop control.

2. The automatic control method of a water supply pump according to claim 1, characterized in that: In step one, the key parameters of the water feed pump and the hydraulic coupling include: water feed pump motor efficiency, input current, input voltage, fluid density, rated flow, head, maximum speed and minimum speed.

3. The automatic control method of a water supply pump according to claim 2, characterized in that: In step 2, the prediction period is the time length for predicting the future behavior of the unit, and the control period is the time interval for adjusting the speed of the feedwater pump each time; The control period is shorter than the prediction period, and is used to adjust the speed of the water feed pump multiple times within the prediction period to cope with changes in the unit.

4. The automatic control method of a water supply pump according to claim 1, characterized in that: In step three, matching the unit load with the forecast period and determining the feedwater pump speed requirement at the end of each forecast period based on the relationship between the unit load and the feedwater pump speed includes the following steps: Obtain historical unit load data and corresponding feedwater pump speed; According to the characteristics of the unit and historical operating data, establish an empirical model of unit load and feedwater pump speed; The historical data is classified according to the forecast period, and input into the empirical model accordingly to calculate the feedwater pump speed requirement at the end of each forecast period; Perform a rationality check on the calculated speed demand to ensure that the speed demand is within the rated speed range of the feed water pump; The feedwater pump speed requirement at the end of each forecast period is recorded and stored for use in subsequent steps.

5. The automatic control method of a water supply pump according to claim 3, characterized in that: In step 4, the pre-established pump efficiency model is: Among them, η is the pump efficiency parameter, ρ is the fluid density, Q is the rated flow rate of the water pump, and H is the head; η m is the motor efficiency, I is the input current, V is the input voltage; The pump efficiency parameter η represents the ratio of the effective output power of the feedwater pump to the input electrical power.

6. The automatic control method of a water supply pump according to claim 5, characterized in that: In step 4, the fluid coupling energy loss model is: ΔP loss =k(N x -N opt ) 2 Among them, ΔP loss is the energy loss parameter, k is the energy loss coefficient, which is used to quantify the relationship between the energy loss of the hydraulic coupling and the degree to which the speed of the feed pump deviates from the speed requirement; N opt is the speed requirement for the next prediction period determined in step 3, N X The ideal speed required to reach the end of the prediction cycle at the current moment; The energy loss parameter ΔP loss represents the energy loss of the hydraulic coupling at different ideal speeds, and the energy loss parameter ΔP loss The result carries the unknown ideal speed N X .

7. The automatic control method of a water supply pump according to claim 6, characterized in that: In step six, the optimization function model is established as follows: Among them, J is the optimization objective function value, T p+1 is the next forecast period, T p is the current prediction period; α is a trade-off factor between 0 and 1, which is used to balance two different goals, namely, reducing the energy loss of the hydraulic coupling and improving the efficiency of the feedwater pump; The smaller the value of the optimization objective function is, the more efficient the system operation is, the smaller the energy loss of the hydraulic coupling is, and the higher the efficiency of the water feed pump is.

8. The automatic control method of a water supply pump according to claim 7, characterized in that: In step 6, the process of determining the ideal speed required from the current moment to the end moment of the prediction cycle under the condition of minimizing the objective function is: Set the maximum speed and minimum speed of the water supply pump as constraints; Calculate several optimization objective function values ​​J by linear programming method; Screen and sort several optimization objective function values ​​J to determine the minimum objective function value J min ; Based on minimizing the objective function value J min Determine the ideal speed N corresponding to it X .

9. The automatic control method of a water supply pump according to claim 1, characterized in that: In step seven, the process of converting the ideal rotation speed into command information and sending it to the electric actuator is completed by a PID controller.

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