Servo energy-saving control system for water outlet pump

Abstract

The invention discloses a water affair water outlet pump servo energy-saving control system, which comprises a water outlet pump motor, a data acquisition system, a central control system and a servo drive control system, and is characterized in that the data acquisition system is used for acquiring real-time parameters in a water affair and water outlet pump operation process; the central control system is connected with the data acquisition system and is used for carrying out PID algorithm and intelligent fuzzy control algorithm operation according to set parameters and real-time parameters acquired by the data acquisition system to obtain a real-time target rotating speed of a water affair water outlet pump motor; the servo drive control system is connected with the central control system and used for receiving a target rotating speed signal sent by the central control system, driving a water outlet pump motor to operate at the corresponding rotating speed and feeding back the actual rotating speed of the water outlet pump motor to the central control system to form closed-loop control, so that intelligent and precise control over the water outlet pump is achieved. On the premise of ensuring stable water operation, the energy consumption is reduced to the maximum extent.

Description

Technical Field

[0001] This invention relates to the field of water treatment equipment control technology, specifically to a servo energy-saving control system for a water effluent pump. Background Technology

[0002] In water treatment processes such as waterworks that require membrane separation, the water effluent pump is the core power equipment. Its main function is to extract the clean water that has passed through membrane filtration from the waterworks, providing a stable water flow for subsequent water treatment processes. Currently, most water effluent pumps on the market use the traditional fixed-frequency control method, meaning that the pump always runs at a fixed speed, and the water output is controlled by adjusting the opening of the outlet valve.

[0003] This traditional control method has obvious drawbacks: On the one hand, valve throttling will generate significant energy loss. When adjusting the flow rate through valves in fixed-frequency control, the energy waste rate can reach 20%-40%, which does not meet the current industry requirements for energy conservation and environmental protection. On the other hand, the water level and membrane flux in the water system will change dynamically with factors such as influent load and membrane fouling. Fixed-frequency pumps cannot respond to these changes quickly, which can easily lead to excessive fluctuations in the water level. This not only affects the filtration efficiency and service life of the membrane module, but may also cause pump idling failure due to low water level, increasing equipment maintenance costs.

[0004] Some companies have attempted to retrofit their water effluent pumps using variable frequency control (VFD) technology. However, conventional VFD control systems rely solely on a single water level signal for speed adjustment, lacking comprehensive consideration of key parameters such as membrane flux, effluent pressure, and influent flow rate. This results in low adjustment accuracy and leaves room for energy savings. Furthermore, conventional VFD systems have a slow response time, making it difficult to adjust pump speed promptly when water levels change abruptly or influent loads shift, thus compromising system stability. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned related technologies, this application provides a servo energy-saving control system for water effluent pumps, which realizes intelligent and precise control of water effluent pumps and minimizes energy consumption while ensuring stable operation of water utilities.

[0006] This application provides a servo-driven energy-saving control system for a water effluent pump, including an effluent pump motor, a data acquisition system, a central control system, and a servo drive control system.

[0007] The data acquisition system is used to collect real-time parameters during the operation of water systems and water pumps. These real-time parameters include:

[0008] The central control system is connected to the data acquisition system and is used to calculate the real-time target speed of the water outlet pump motor by performing PID algorithm and intelligent fuzzy control algorithm calculations based on the set parameters and the real-time parameters collected by the data acquisition system.

[0009] The servo drive control system is connected to the central control system and is used to receive the target speed signal sent by the central control system, drive the water pump motor to run at the corresponding speed, and feed back the actual speed of the water pump motor to the central control system to form a closed-loop control.

[0010] Preferably, the control formula of the PID algorithm is:

[0011] Δu(k)=K′p[e(k)-e(k-1)]+K′ie(k)+K′d[e(k)-2e(k-1)+e(k-2)]

[0012] Where: Δu(k) is the control increment at the kth sampling time;

[0013] K′ p K′ i and K′ d These are the proportional, integral, and derivative parameters of the PID after dynamic adjustment by fuzzy control; e(k) is the deviation value at the kth sampling.

[0014] e(k-1) and e(k-2) are the deviation values ​​at the (k-1)th and (k-2)th sampling times, respectively.

[0015] Preferably, the deviation value includes the difference between the target water level and the actual water level and / or the difference between the target membrane flux and the actual membrane flux.

[0016] Preferred formula for adjusting PID parameters using fuzzy control:

[0017] K′p=Kp0+ΔKp

[0018] K′i=Ki0+ΔKi

[0019] K′d=Kd0+ΔKd

[0020] in:

[0021] K p0 K i0 and K d0 These are the initial baseline parameters for the PID controller;

[0022] ΔK p ΔK i and ΔK d These are the adjustment values ​​for the PID parameters output by the fuzzy control, specifically:

[0023] ΔK p =F1(E, EC), ΔK i =F2(E,EC), ΔKd=F3(E,EC)

[0024] Where E is the deviation vector, EC is the deviation rate vector, and F1, F2, and F3 are fuzzy control rule functions.

[0025] Preferably, the defuzzification formula for the fuzzy control is:

[0026]

[0027] Where: ΔKp is the adjustment amount of the PID proportional parameter after defuzzification;

[0028] μi is the membership degree of the i-th fuzzy rule;

[0029] ΔKpi is the center value of the output ΔKp corresponding to the i-th fuzzy rule;

[0030] The same applies to the defuzzification calculation of ΔKi and ΔKd.

[0031] Preferably, the speed deviation formula for the closed-loop control is:

[0032] Δn=n target (k)-n actual (k)

[0033] Where: Δn is the rotational speed deviation;

[0034] n target (k) represents the target rotational speed calculated by the central control system at the kth sampling time;

[0035] n actual (k): The actual rotational speed fed back by the servo motor at the kth sampling.

[0036] Preferably, the water pump motor is a permanent magnet synchronous servo motor, and the electromagnetic torque formula of the permanent magnet synchronous servo motor is:

[0037] T e =1.5p[ψ f i q +(L d -L q )i d i q ]

[0038] Wherein: T e This refers to the electromagnetic torque of the motor.

[0039] p is the number of pole pairs of the motor;

[0040] ψ f For rotor permanent magnet flux linkage;

[0041] i d and i q These are the stator current components along the d-axis and q-axis, respectively.

[0042] L d and L q These are the stator inductances along the d-axis and q-axis, respectively.

[0043] Preferably, the central control module is equipped with a safety threshold. When the parameters collected by the parameter acquisition module exceed the safety threshold, the central control module triggers a fault signal, issues an alarm through the human-machine interaction module, and controls the servo drive controller to adjust the speed of the permanent magnet synchronous servo motor or stop its operation.

[0044] A method for operating a servo energy-saving control system for a water effluent pump includes the following steps:

[0045] S1 sets target parameters and safety thresholds in the central control system. The target parameters include target water level, target membrane flux, and target effluent pressure.

[0046] The S2 parameter acquisition module collects parameters in real time, including water level, membrane flux, influent flow rate, outlet pump motor current, outlet pump motor voltage, and outlet pressure, and transmits the data to the central control system.

[0047] The S3 central control system receives real-time parameters from the parameter acquisition module, processes them, compares them with the target parameters set by the user, and calculates the deviation value.

[0048] The S4 central control system uses a PID combined with fuzzy control algorithm to calculate the target speed of the water pump motor and sends the target speed signal to the servo drive controller.

[0049] The S5 servo drive controller drives the water pump motor to run at the corresponding speed according to the target speed signal, and adjusts the water output. At the same time, it feeds back the actual speed of the water pump motor to the central control system to form a closed-loop control.

[0050] When the real-time parameters acquired by the parameter acquisition module exceed the safety threshold, the central control module triggers a fault signal, issues an alarm through the human-machine interface module, and controls the servo drive controller to adjust the speed of the permanent magnet synchronous servo motor or stop its operation, while simultaneously activating safety protection measures.

[0051] Compared with related technologies, the present invention has the following advantages:

[0052] The central control system of this invention combines PID algorithm with intelligent fuzzy control algorithm. It continuously adjusts the target speed of the water pump motor according to the real-time parameters collected by the data acquisition system. The servo drive controller drives the water pump motor according to the target speed. The actual speed of the water pump motor is fed back to the central control system to form a closed-loop control, so as to continuously optimize the working state of the water pump motor, thereby minimizing energy consumption while ensuring stable water supply operation.

[0053] When the real-time parameters collected by the parameter acquisition module exceed the safety threshold, the central control module triggers a fault signal, issues an alarm through the human-machine interface module, and controls the servo drive controller to adjust the speed of the permanent magnet synchronous servo motor or stop its operation. At the same time, safety protection measures are activated to ensure production safety. Detailed Implementation

[0054] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0055] A servo-driven energy-saving control system for water effluent pumps, taking a membrane tank effluent pump servo-driven energy-saving control system as an example, includes an effluent pump motor, a data acquisition system, a central control system, and a servo drive control system.

[0056] The data acquisition system is used to collect real-time parameters during the operation of the membrane tank and the effluent pump. The real-time parameters include membrane tank water level, membrane flux, influent flow rate, effluent pump motor current, effluent pump motor voltage and effluent pressure, and transmit the data to the central control system.

[0057] The central control system is connected to the data acquisition system and is used to calculate the real-time target speed of the membrane tank effluent pump motor based on the set parameters and the real-time parameters acquired by the data acquisition system using PID algorithm and intelligent fuzzy control algorithm. The control formula of the PID algorithm is as follows:

[0058] Δu(k)=K′p[e(k)-e(k-1)]+K′ie(k)+K′d[e(k)-2e(k-1)+e(k-2)]

[0059] Where: Δu(k) is the control increment at the kth sampling; K′ p K′ i and K′ d These are the proportional, integral, and derivative parameters of the PID controller after dynamic adjustment via fuzzy control; e(k) is the deviation value at the k-th sampling (e.g., the difference between the target water level h0 and the actual water level h). (k) The difference e h =h0-h (k) The target membrane flux J0 and the actual membrane flux J (k) The difference e J =J0-J (k) e(k-1) and e(k-2) are the deviation values ​​at the (k-1)th and (k-2)th sampling times, respectively.

[0060] Formula for adjusting PID parameters in fuzzy control:

[0061] K′p=Kp0+ΔKp

[0062] K′i=Ki0+ΔKi

[0063] K′d=Kd0+ΔKd

[0064] Where: K p0 K i0 and K d0 These are the initial baseline parameters for the PID controller; ΔK p ΔK i and ΔK d These are the PID parameter adjustments for the fuzzy control output, specifically: ΔK p =F1(E, EC), ΔK i =F2(E, EC), ΔKd = F3(E, EC), where E is the deviation vector (e.g., e h e J e Qin EC is the deviation change rate vector (e.g., Δh / Δt, ΔJ / Δt, ΔQin / Δt), and F1, F2 and F3 are fuzzy control rule functions.

[0065] The defuzzification formula for fuzzy control is:

[0066]

[0067] Where: ΔKp is the adjustment amount of the PID proportional parameter after defuzzification; μi is the membership degree of the i-th fuzzy rule; ΔKpi is the center value of the output ΔKp corresponding to the i-th fuzzy rule; similarly, the defuzzification calculation of ΔKi and ΔKd is applied.

[0068] The formula for the speed deviation in closed-loop control is:

[0069] Δn=n target (k)-n actual (k)

[0070] Where: Δn is the rotational speed deviation; n target (k) represents the target rotational speed calculated by the central control system at the k-th sampling time; n actual (k): The actual rotational speed fed back by the servo motor at the kth sampling.

[0071] The servo drive control system is connected to the central control system to receive the target speed signal from the central control system, drive the outlet pump motor to run at the corresponding speed, and feed back the actual speed of the outlet pump motor to the central control system to form a closed-loop control. The outlet pump motor is a permanent magnet synchronous servo motor, and the electromagnetic torque formula of the permanent magnet synchronous servo motor is:

[0072] T e=1.5p[ψ f i q +(L d -L q )i d i q ]

[0073] Wherein: T e ψ is the electromagnetic torque of the motor; p is the number of pole pairs of the motor; f For rotor permanent magnet flux linkage; i d and i q These are the d-axis and q-axis stator current components, respectively; L d and L q These are the stator inductances along the d-axis and q-axis, respectively.

[0074] The central control module is set with a safety threshold. When the parameters collected by the parameter acquisition module exceed the safety threshold, the central control module triggers a fault signal, issues an alarm through the human-machine interaction module, and controls the servo drive controller to adjust the speed of the permanent magnet synchronous servo motor or stop its operation.

[0075] The working method of the above-mentioned membrane tank effluent pump servo energy-saving control system includes the following steps:

[0076] S1 sets target parameters and safety thresholds in the central control system. The target parameters include target water level, target membrane flux, and target effluent pressure.

[0077] The S2 parameter acquisition module collects parameters in real time, including membrane tank water level, membrane flux, influent flow rate, effluent pump motor current, effluent pump motor voltage, and effluent pressure, and transmits the data to the central control system.

[0078] The S3 central control system receives real-time acquired parameters from the parameter acquisition module, processes them, compares them with the target parameters set by the user, and calculates the deviation value.

[0079] The S4 central control system uses a PID combined with fuzzy control algorithm to calculate the target speed of the water pump motor and sends the target speed signal to the servo drive controller.

[0080] The S5 servo drive controller drives the water pump motor to run at the corresponding speed according to the target speed signal, and adjusts the water output; at the same time, it feeds back the actual speed of the motor to the central control system to form a closed-loop control.

[0081] When the real-time parameters acquired by the parameter acquisition module exceed the safety threshold, the central control module triggers a fault signal, issues an alarm through the human-machine interface module, and controls the servo drive controller to adjust the speed of the permanent magnet synchronous servo motor or stop its operation, while simultaneously activating safety protection measures.

[0082] Example 1

[0083] Before the upgrade: The Jiangdong Water Plant's membrane workshop used submerged ultrafiltration membrane technology, with a production capacity of 200,000 tons / day. It had 24 membrane tanks, each equipped with one set of effluent pumps. The workshop had high energy consumption, primarily due to the electrical energy consumed by the motors of the effluent pumps. Each membrane tank's motor had a power of 18.5kW. The effluent pump motors were ordinary asynchronous three-phase motors controlled by frequency converters. Each membrane tank's control system was independent, consisting of a PLC controller and related modules, ultimately connecting to the central control system.

[0084] Current configuration of main equipment for a single membrane tank effluent pump (ordinary variable frequency system)

[0085]

[0086] The energy-saving control system of the membrane tank outlet pump is modified using the technical solution of this invention.

[0087] The overall energy-saving control system consists of a servo vector control system and a PID algorithm and intelligent fuzzy control algorithm control system.

[0088] 1. The servo vector control system consists of a synchronous servo motor, a servo vector drive controller, and a rotary encoder. It replaces the original frequency converter system and asynchronous three-phase motor in the membrane tank. Synchronous servo motors are characterized by high precision, fast response, and low energy consumption. They also feature low speed and high torque, and since high speeds are often not required in actual operation, energy efficiency is significantly improved. The servo vector drive controller and the synchronous servo motor use digital control signals, while the frequency converter uses analog signals. Digital signals are superior to analog signals in terms of accuracy, transmission speed, and anti-interference capability.

[0089] 2. The Fuzzy PID Logic Intelligent (AI) Algorithm Control System is the core of a control system composed of a PLC controller, AI / AO modules, etc. It is responsible for connecting with the production system in the central control room and controlling the operation of the servo vector control system. The control system uses a fuzzy PID logic intelligent (AI) algorithm [application of a fuzzy PID control intelligent algorithm based on fuzzy predictive (AI) control and classical PID control to respond promptly to environmental and load changes. During the control process, through the collection of rich information such as frequency signals, pressure, and flow, and utilizing high-speed computing, tracking, judgment, and reasoning capabilities, the control logic model integrates the operating information of the entire system, optimizes and dynamically adjusts the operating parameters of the servo control system, and achieves coordinated system operation to achieve optimal overall system performance]. Adjustments are made according to the characteristics of the servo vector drive controller, and a three-way closed loop is formed between the speed and position signals of the servo motor and the current inside the drive controller, improving the overall adaptability of the control system. Simultaneously, the fuzzy PID intelligent algorithm can automatically adjust the output power of the motor according to the torque load and speed changes of the servo motor, achieving precise control and optimal operation, thus realizing overall energy-saving control of the system.

[0090] The No. 24 membrane tank effluent pump was upgraded and transformed through a "hardware + software" energy-saving control system, achieving energy saving and consumption reduction while ensuring safe operation.

[0091] Effect verification:

[0092]

[0093]

[0094] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A servo-energy-saving control system for a water effluent pump, characterized in that, This includes the water pump motor, data acquisition system, central control system, and servo drive control system. The data acquisition system is used to collect real-time parameters during the operation of water supply and water pumps. The central control system is connected to the data acquisition system and is used to calculate the real-time target speed of the water outlet pump motor by performing PID algorithm and intelligent fuzzy control algorithm calculations based on the set parameters and the real-time parameters collected by the data acquisition system. The servo drive control system is connected to the central control system and is used to receive the target speed signal sent by the central control system, drive the water pump motor to run at the corresponding speed, and feed back the actual speed of the water pump motor to the central control system to form a closed-loop control.

2. The water effluent pump servo energy-saving control system according to claim 1, characterized in that, The control formula for the PID algorithm is: Δu(k)=K′p[e(k)-e(k-1)]+K′ie(k)+K′d[e(k)-2e(k-1)+e(k-2)] Where: Δu(k) is the control increment at the kth sampling time; K′ p K′ i and K′ d These are the PID proportional, integral, and derivative parameters after dynamic adjustment via fuzzy control; e(k) is the deviation value at the kth sampling point; e(k-1) and e(k-2) are the deviation values ​​at the (k-1)th and (k-2)th sampling times, respectively.

3. The water effluent pump servo energy-saving control system according to claim 2, characterized in that, The deviation value includes the difference between the target water level and the actual water level and / or the difference between the target membrane flux and the actual membrane flux.

4. The water effluent pump servo energy-saving control system according to claim 1, characterized in that, Formula for adjusting PID parameters in fuzzy control: K′p=Kp0+ΔKp K′i=Ki0+ΔKi K′d=Kd0+ΔKd in: K p0 K i0 and K d0 These are the initial baseline parameters for the PID controller; ΔK p ΔK i and ΔK d These are the adjustment values ​​for the PID parameters output by the fuzzy control, specifically: ΔK p =F1(E,EC),ΔK i =F2(E,EC),ΔKd=F3(E,EC) Where E is the deviation vector, EC is the deviation rate vector, and F1, F2, and F3 are fuzzy control rule functions.

5. The water effluent pump servo energy-saving control system according to claim 1, characterized in that, The defuzzification formula for the fuzzy control is: Where: ΔKp is the adjustment amount of the PID proportional parameter after defuzzification; μi is the membership degree of the i-th fuzzy rule; ΔKpi is the center value of the output ΔKp corresponding to the i-th fuzzy rule; The same applies to the defuzzification calculation of ΔKi and ΔKd.

6. The water effluent pump servo energy-saving control system according to claim 1, characterized in that, The speed deviation formula for the closed-loop control is: Δn=n target (k)-n actual (k) Where: Δn is the rotational speed deviation; n target (k) represents the target rotational speed calculated by the central control system at the kth sampling time; n actual (k): The actual rotational speed fed back by the servo motor at the kth sampling.

7. The water effluent pump servo energy-saving control system according to claim 1, characterized in that, The water pump motor is a permanent magnet synchronous servo motor, and the electromagnetic torque formula of the permanent magnet synchronous servo motor is: T e =1.5p[ψ f i q +(L d -L q )i d i q ] Wherein: T e This refers to the electromagnetic torque of the motor. p is the number of pole pairs of the motor; ψ f For rotor permanent magnet flux linkage; i d and i q These are the stator current components along the d-axis and q-axis, respectively. L d and L q These are the stator inductances along the d-axis and q-axis, respectively.

8. The water effluent pump servo energy-saving control system according to claim 1, characterized in that, The central control module is set with a safety threshold. When the parameters collected by the parameter acquisition module exceed the safety threshold, the central control module triggers a fault signal, issues an alarm through the human-machine interface module, and controls the servo drive controller to adjust the speed of the permanent magnet synchronous servo motor or stop its operation.

9. The working method of the water supply pump servo energy-saving control system as described in claims 1-8, characterized in that, Includes the following steps: S1 sets target parameters and safety thresholds in the central control system. The target parameters include target water level, target membrane flux, and target effluent pressure. The S2 parameter acquisition module collects parameters in real time, including water level, membrane flux, influent flow rate, outlet pump motor current, outlet pump motor voltage, and outlet pressure, and transmits the data to the central control system. The S3 central control system receives real-time acquired parameters from the parameter acquisition module, processes them, compares them with the target parameters set by the user, and calculates the deviation value. The S4 central control system uses a PID combined with fuzzy control algorithm to calculate the target speed of the water pump motor and sends the target speed signal to the servo drive controller. The S5 servo drive controller drives the water pump motor to run at the corresponding speed according to the target speed signal, and adjusts the water output; at the same time, it feeds back the actual speed of the motor to the central control system to form a closed-loop control. When the real-time parameters acquired by the parameter acquisition module exceed the safety threshold, the central control module triggers a fault signal, issues an alarm through the human-machine interface module, and controls the servo drive controller to adjust the speed of the permanent magnet synchronous servo motor or stop its operation, while simultaneously activating safety protection measures.

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