A submersible digital pump and digital control system

Abstract

This application relates to the technical field of submersible pumps, and discloses a submersible digital pump and a digital control system. The digital control system includes a data acquisition module, a calculation module, an identification module, a strategy module, and a control module. Specifically: the data acquisition module collects the operating parameters and status parameters of the submersible digital pump; the calculation module calculates the operating efficiency and efficiency deviation value of the submersible digital pump; the identification module identifies the load responsiveness and structural compatibility of the efficiency deviation value, and identifies inefficient operating conditions of the submersible digital pump; the strategy module formulates an efficiency adjustment strategy; and the control module generates a speed control command based on the efficiency adjustment strategy, and adjusts the operating efficiency of the submersible digital pump in inefficient operating conditions based on the speed control command. This application achieves intelligent identification and adaptive control of the operating efficiency of the submersible digital pump, improving the operational stability of the submersible digital pump.

Description

Technical Field

[0001] This application relates to the technical field of submersible pumps, specifically to a submersible digital pump and its digital control system. Background Technology

[0002] With advancements in motor control and sensor technologies, traditional submersible pumps are gradually evolving towards digitalization, forming submersible digital pumps centered around digital motors and control systems. Digital motors offer high responsiveness and efficiency, while digital control systems provide more precise monitoring and control capabilities for the submersible pump's operating status. However, current submersible digital pump control technology still has some shortcomings.

[0003] Currently, most digital control systems rely solely on operating parameters such as current, voltage, and speed, lacking comprehensive monitoring of the submersible pump's internal operating and structural states. This leads to over-reliance on surface-level data in their adjustment strategies, making it difficult to determine whether efficiency decline is caused by operational deviations or other irregular disturbances. This blind adjustment approach easily triggers unnecessary adjustments, resulting in oscillations, over-adjustment, increased energy consumption, and ultimately, equipment damage. Traditional efficiency adjustment methods typically use the current efficiency deviation as input, lacking a global understanding of efficiency trends. In actual operation, efficiency fluctuations often exhibit short-cycle flickering or quasi-periodic pulse patterns, easily interfering with the adjustment algorithm. Consequently, the adjustment strategy not only fails to improve efficiency but may even exacerbate system load.

[0004] For example, Chinese patent application CN110529400A discloses a submersible pump control system and its control method. The submersible pump includes a submersible pump working body fixed to the bottom of a pool, a buoy device for suspending on the pool surface, an automatic rangefinder for controlling the power output of the submersible pump working body, a control module, a communication module for communication with a management client, and a management client. This solution uses the buoy device to suspend on the pool surface, ensuring that the automatic rangefinder measures effective water depth data. The corresponding data is then transmitted to the management client via the communication module, achieving real-time monitoring of the submersible pump's working status. When the management client directly controls the submersible pump's working status through the control module, it effectively avoids idling, over-operation, and low efficiency, thus improving the submersible pump's efficiency. However, this solution still suffers from the problem mentioned in the background of this application: a lack of monitoring of the submersible pump's internal operating and structural states, which can easily trigger adjustment operations unnecessarily.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The technical problem to be solved by this application is to overcome the defects of the prior art and provide a submersible digital pump and digital control system, so as to realize intelligent identification and adaptive control of the operating efficiency of the submersible digital pump and improve the operating stability of the submersible digital pump.

[0007] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0008] On the one hand, this application provides a digital control system, including a data acquisition module, a calculation module, a recognition module, a strategy module, and a control module; the functions of each module are as follows: Figure 2 As shown. Wherein:

[0009] The data acquisition module is used to collect the operating parameters and status parameters of the submersible digital pump;

[0010] The calculation module calculates the operating efficiency and efficiency deviation value of the submersible digital pump based on the operating parameters;

[0011] The identification module identifies the load responsiveness and structural coordination of efficiency deviation values ​​based on the operating parameters and status parameters, and identifies the inefficient operating conditions of the submersible digital pump based on the load responsiveness and structural coordination.

[0012] The strategy module is used to formulate efficiency adjustment strategies, including: setting adjustment cycles; calculating the efficiency density of each adjustment cycle based on the operating efficiency; and setting adjustment compensation factors based on the efficiency density.

[0013] The control module generates speed control commands based on the efficiency adjustment strategy, and adjusts the operating efficiency of the submersible digital pump in an inefficient operating condition based on the speed control commands.

[0014] As a preferred embodiment of the digital control system described in this application, the operating parameters include speed, motor current, and motor voltage; the status parameters include winding temperature, upper bearing temperature, and lower bearing temperature.

[0015] The calculation module includes a storage unit and a calculation unit; wherein, the storage unit is configured with the operating characteristic curves of the submersible digital pump at different speeds; the calculation unit calculates the operating efficiency and efficiency deviation value of the submersible digital pump based on the operating parameters and the operating characteristic curves;

[0016] The operating characteristic curves include flow-power curves and flow-head curves; any flow-power curve is the curve showing the change of input power of the submersible digital pump with flow rate at the corresponding speed; any flow-head curve is the curve showing the change of head of the submersible digital pump with flow rate at the corresponding speed.

[0017] As a preferred embodiment of the digital control system described in this application, the calculation of the operating efficiency of the submersible digital pump specifically includes:

[0018] Calculate the current input power of the submersible digital pump based on the motor current and motor voltage;

[0019] Based on the rotational speed, obtain the corresponding flow-power curve and flow-head curve; based on the flow-power curve, query the flow rate corresponding to the current input power to obtain the current flow rate;

[0020] Based on the flow-head curve, query the head corresponding to the current flow rate to obtain the current head;

[0021] Calculate the operating power of the submersible digital pump based on the current flow rate and current head;

[0022] The operating efficiency of a submersible digital pump is calculated based on its operating power and current input power; wherein, the operating efficiency is the ratio of the operating power of the submersible digital pump to the current input power.

[0023] As a preferred embodiment of the digital control system described in this application, the storage unit is further configured with a reference operating efficiency and an efficiency deviation threshold for the submersible digital pump; the calculation unit calculates the efficiency deviation value of the submersible digital pump based on the operating efficiency and the reference operating efficiency; if the operating efficiency is greater than or equal to the reference operating efficiency, the efficiency deviation value is 0; otherwise, the efficiency deviation value is the difference between the reference operating efficiency and the operating efficiency; if the efficiency deviation value is greater than the efficiency deviation threshold for at least m consecutive time points, the calculation unit sends an identification command to the identification module to trigger the identification of the inefficient operating condition of the submersible digital pump; m is a positive integer.

[0024] As a preferred embodiment of the digital control system described in this application, if the efficiency deviation value has at least one of load responsiveness and structural synergy, the submersible digital pump is in an inefficient operating condition.

[0025] The identification module includes a first identification unit; the first identification unit is configured with a first identification strategy for identifying the load responsiveness of efficiency deviation values; the first identification strategy specifically includes:

[0026] The efficiency deviation values ​​at each time point are arranged in chronological order to form a time series of efficiency deviation values.

[0027] Organize the motor current at each time point into a time series of motor current; organize the winding temperature at each time point into a time series of winding temperature;

[0028] Calculate the mean of all elements in the time series of motor current to obtain the average current; calculate the mean of all elements in the time series of winding temperature to obtain the average winding temperature; calculate the cross-correlation coefficient between the time series of motor current and winding temperature and the time series of efficiency deviation.

[0029] The first identification unit is also configured with a current threshold, a winding temperature threshold, and a load correlation threshold; if the average current is greater than the current threshold, the average winding temperature is greater than the winding temperature threshold, and the cross-correlation coefficient is greater than the load correlation threshold, then the efficiency deviation value exhibits load responsiveness.

[0030] In a preferred embodiment of the digital control system described in this application, the identification module further includes a second identification unit; the second identification unit is configured with a second identification strategy for identifying the structural synergy of efficiency deviation values; the second identification strategy specifically includes:

[0031] Calculate the average of the upper and lower bearing temperatures at each time point, and use this as the bearing temperature at each time point; then arrange the bearing temperatures at each time point in chronological order to form a time series of bearing temperatures.

[0032] The mean of all elements in the time series of bearing temperature is calculated as the average bearing temperature; the bearing temperature is predicted based on the time series of bearing temperature to obtain the predicted bearing temperature for at least n consecutive time points in the future; n is a positive integer;

[0033] The second identification unit is also equipped with a bearing temperature threshold. If the average bearing temperature and the predicted bearing temperature at n time points are both greater than the bearing temperature threshold, then the efficiency deviation value exhibits structural synergy.

[0034] In a preferred embodiment of the digital control system described in this application, the strategy module includes an efficiency identification unit and an adjustment compensation unit; wherein the efficiency identification unit is used to set the adjustment period and calculate the efficiency density for each adjustment period; specifically including:

[0035] The operational efficiency at each point in time is organized into a time series of operational efficiency in chronological order.

[0036] Set the cycle length of the adjustment period; divide the time series of operating efficiency into continuous adjustment periods based on the cycle length;

[0037] Each operating efficiency in each adjustment cycle is discretized to obtain the operating efficiency label at each time point in each adjustment cycle;

[0038] For any adjustment cycle, count the number of times each operating efficiency label appears, and mark the operating efficiency label with the most occurrences as the dominant efficiency label;

[0039] The efficiency density of each adjustment cycle is calculated based on the dominant efficiency label; whereby the efficiency density of any adjustment cycle is the ratio of the number of occurrences of the dominant efficiency label to the cycle length.

[0040] In a preferred embodiment of the digital control system described in this application, the efficiency identification unit is further configured to calculate the efficiency density gradient for each adjustment cycle, specifically including:

[0041] For any adjustment period, calculate the absolute value of the difference between the number of occurrences of the dominant efficiency label and the number of occurrences of the dominant efficiency label in the adjacent previous adjustment period, and use it as the efficiency density change for the corresponding adjustment period; calculate the ratio of the efficiency density change to the period length to obtain the efficiency density gradient.

[0042] The strategy module also includes an adjustment and compensation unit;

[0043] The adjustment and compensation unit is used to set the adjustment and compensation factor, specifically including:

[0044] Set the value range of the adjustment compensation factor; set the adjustment compensation factor for each adjustment period; specifically, based on the efficiency density and efficiency density gradient of each adjustment period, assign a value to the adjustment compensation factor in the value range, and the magnitude of the efficiency density is positively correlated with the value of the adjustment compensation factor, and the magnitude of the efficiency density gradient is negatively correlated with the value of the adjustment compensation factor.

[0045] As a preferred embodiment of the digital control system described in this application, the control module includes a speed calculation unit and a control command unit. The speed calculation unit calculates the speed adjustment amount based on the efficiency deviation value in each adjustment cycle. The control command unit adjusts and compensates the speed adjustment amount based on an adjustment compensation factor and generates a speed control command. Specifically, this includes calculating the product of the adjustment compensation factor and the speed adjustment amount as the adjusted and compensated speed adjustment amount, and generating a speed control command containing the speed adjustment amount. The control command unit sends the speed control command to the digital motor of the submersible digital pump, and the digital motor adjusts the speed of the submersible digital pump based on the speed adjustment amount contained in the speed control command.

[0046] The speed calculation unit is equipped with a PID controller, and calculates the speed adjustment amount based on the PID controller. Specifically, it includes: inputting the time series of the efficiency deviation value into the PID controller, the PID controller automatically calculating the derivative and integral of the efficiency deviation value over time, and calculating the speed adjustment amount based on the efficiency deviation value and its derivative and integral.

[0047] Secondly, this application provides a submersible digital pump, including a pump head, a digital motor, and the digital control system described in this application; wherein:

[0048] The pump head is used for the intake, pressurization, and output of liquids;

[0049] The digital motor includes a winding core, a rotor assembly, an upper bearing, and a lower bearing, and is used to provide driving force for the operation of the pump head;

[0050] The digital control system is used to monitor the operating efficiency of the pump head and the digital motor; if the pump head and the digital motor are in an inefficient operating condition, the digital control system improves the operating efficiency by adjusting the speed of the rotor assembly in the digital motor.

[0051] Compared with the prior art, the beneficial effects achieved by this application are as follows:

[0052] This application enables real-time monitoring and intelligent control of the operating status of submersible digital pumps, which can trigger corresponding adjustment actions when the pump body is in an inefficient operating condition, thereby effectively improving the operating efficiency of submersible digital pumps and enhancing the adaptability of digital pumps under different loads and operating conditions.

[0053] This application can distinguish between the actual efficiency decline caused by the deterioration of pump operating conditions and the abnormal efficiency fluctuations caused by external disturbances, thus avoiding unnecessary adjustment operations due to misjudgment and reducing the risk of adjustment oscillation.

[0054] This application dynamically assesses the stability and trend of operating efficiency through efficiency density and efficiency density gradient, thereby achieving flexible adjustment and compensation, which enhances the intelligence level and efficiency adjustment capability of submersible digital pumps. Attached Figure Description

[0055] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0056] Figure 1 A schematic diagram of the structure of a digital control system provided in this application;

[0057] Figure 2 A functional schematic diagram of a digital control system provided in this application.

[0058] Figure 3 This is a structural schematic diagram of a submersible digital pump provided in this application. Detailed Implementation

[0059] The technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of this application, rather than limitations thereof. In the absence of conflict, the embodiments and technical features in the embodiments can be combined with each other.

[0060] Example 1

[0061] This embodiment describes a digital control system, referring to... Figure 1 The system includes a data acquisition module, a calculation module, a recognition module, a strategy module, and a control module; among which:

[0062] The data acquisition module is used to collect the operating parameters and status parameters of the submersible digital pump;

[0063] The data acquisition module includes an operation monitoring unit and a status monitoring unit; wherein, the operation monitoring unit is used to acquire the operating parameters of the submersible digital pump; the operating parameters include speed, motor current, and motor voltage; the speed is the speed of the rotor assembly of the digital motor in the submersible digital pump;

[0064] The status monitoring unit is used to collect status parameters of the submersible digital pump, including winding temperature, upper bearing temperature, and lower bearing temperature. The status monitoring unit is equipped with thermistors installed at the winding core of the digital motor in the submersible digital pump, as well as at the upper and lower bearings, enabling real-time collection of status parameters including winding temperature, upper bearing temperature, and lower bearing temperature.

[0065] The calculation module calculates the operating efficiency and efficiency deviation value of the submersible digital pump based on the operating parameters;

[0066] The calculation module includes a storage unit and a calculation unit. The storage unit is configured with operating characteristic curves of the submersible digital pump at different speeds. The calculation unit calculates the operating efficiency and efficiency deviation of the submersible digital pump based on the operating parameters and the operating characteristic curves. The operating characteristic curves include a flow-power curve and a flow-head curve. Each flow-power curve represents the change in input power of the submersible digital pump with flow rate at a corresponding speed. Each point on the flow-power curve corresponds to a flow rate and input power, indicating the input power required for the submersible digital pump to maintain the corresponding flow rate. The greater the flow rate, the greater the water resistance, and the greater the input power required for the submersible digital pump to drive the impeller to overcome the resistance.

[0067] Any flow-head curve represents the change in head of a submersible digital pump with flow rate at a corresponding speed. Each point on the flow-head curve corresponds to a flow rate and a head, indicating the magnitude of the head output by the submersible digital pump at the corresponding flow rate.

[0068] The calculation of the operating efficiency of the submersible digital pump specifically includes:

[0069] Calculate the current input power of the submersible digital pump based on the motor current and motor voltage;

[0070] Based on the rotational speed, obtain the corresponding flow-power curve and flow-head curve; based on the flow-power curve, query the flow rate corresponding to the current input power to obtain the current flow rate;

[0071] Based on the flow-head curve, query the head corresponding to the current flow rate to obtain the current head;

[0072] The operating power of the submersible digital pump is calculated based on the current flow rate and current head; the formula is as follows:

[0073] ;

[0074] Where P represents operating power, The value represents the liquid density, g represents the gravitational acceleration, Q represents the current flow rate, and H represents the current head.

[0075] The operating efficiency of a submersible digital pump is calculated based on its operating power and current input power; wherein, the operating efficiency is the ratio of the operating power of the submersible digital pump to the current input power.

[0076] The storage unit is also configured with a reference operating efficiency and an efficiency deviation threshold for the submersible digital pump; the calculation unit calculates the efficiency deviation value of the submersible digital pump based on the operating efficiency and the reference operating efficiency; if the operating efficiency is greater than or equal to the reference operating efficiency, the efficiency deviation value is 0; otherwise, the efficiency deviation value is the difference between the reference operating efficiency and the operating efficiency; if the efficiency deviation value is greater than the efficiency deviation threshold for at least m consecutive time points, the calculation unit sends an identification command to the identification module to trigger the identification of the inefficient operating condition of the submersible digital pump; m is a positive integer.

[0077] The identification module identifies the load responsiveness and structural coordination of efficiency deviation values ​​based on the operating parameters and status parameters, and identifies the inefficient operating conditions of the submersible digital pump based on the load responsiveness and structural coordination.

[0078] If the efficiency deviation value exhibits at least one of the characteristics of load responsiveness and structural synergy, the submersible digital pump is operating in an inefficient condition.

[0079] The identification module includes a first identification unit and a second identification unit; wherein, the first identification unit is configured with a first identification strategy for identifying the load responsiveness of efficiency deviation values; the first identification strategy specifically includes:

[0080] The efficiency deviation values ​​at each time point are arranged in chronological order to form a time series of efficiency deviation values.

[0081] Organize the motor current at each time point into a time series of motor current; organize the winding temperature at each time point into a time series of winding temperature;

[0082] Calculate the mean of all elements in the time series of motor current to obtain the average current; calculate the mean of all elements in the time series of winding temperature to obtain the average winding temperature; calculate the cross-correlation coefficient between the time series of any one of the motor current and winding temperature and the time series of efficiency deviation.

[0083] Optionally, the cross-correlation coefficient between the time series of motor current or winding temperature and the time series of efficiency deviation values ​​is calculated based on the cross-correlation function at different lag times. A lag time window is set, and the maximum cross-correlation coefficient at all lag times within the lag time window is taken. The lag time window is set based on experimental data or experience to limit the range of lag time values, preventing the lag time from being too large, which would cause the cross-correlation coefficient to lose its practical significance and fail to reflect the correlation between the decrease in operating efficiency and the increase in motor current or winding temperature.

[0084] The first identification unit is also configured with a current threshold, a winding temperature threshold, and a load correlation threshold; if the average current is greater than the current threshold, the average winding temperature is greater than the winding temperature threshold, and the cross-correlation coefficient is greater than the load correlation threshold, then the efficiency deviation value exhibits load responsiveness.

[0085] When the electromagnetic load on a submersible digital pump increases, such as due to inlet blockage or increased liquid impurity content, the operating power increases while the flow rate decreases, resulting in low operating efficiency. The submersible digital pump operates in an inefficient condition that allows for proactive intervention. For example, appropriately reducing the speed can decrease the load, reduce shear losses in the pumped liquid, prevent overloading of the digital motor, and restore operating efficiency to the expected level. If the electromagnetic load increases, the motor current increases, leading to a corresponding increase in winding temperature. This application uses a first identification strategy to distinguish this abnormal operating efficiency caused by increased electromagnetic load, i.e., to determine whether the efficiency deviation value exhibits load responsiveness. If so, it confirms that the electromagnetic load has increased, allowing for proactive intervention.

[0086] The second identification unit is configured with a second identification strategy for identifying the structural synergy of efficiency deviation values; the second identification strategy specifically includes:

[0087] Calculate the average of the upper and lower bearing temperatures at each time point, and use this as the bearing temperature at each time point; then arrange the bearing temperatures at each time point in chronological order to form a time series of bearing temperatures.

[0088] The mean of all elements in the time series of bearing temperature is calculated as the average bearing temperature; the bearing temperature is predicted based on the time series of bearing temperature to obtain the predicted bearing temperature for at least n consecutive time points in the future; n is a positive integer;

[0089] Optionally, the second identification unit is equipped with a trained time series prediction model, which is any one of a long short-term memory network model, a gated recurrent unit model, an autoregressive moving average model, etc.; the second identification unit performs supplementary prediction on the time series of bearing temperature based on the time series prediction model to obtain the predicted value of bearing temperature.

[0090] The second identification unit is also equipped with a bearing temperature threshold. If the average bearing temperature and the predicted bearing temperature at n time points are both greater than the bearing temperature threshold, then the efficiency deviation value exhibits structural synergy.

[0091] When a submersible digital pump has structural abnormalities such as impeller wear or insufficient bearing lubrication, the rotor assembly may become misaligned or obstructed, leading to increased bearing friction and vibration. This results in mechanical power loss, placing the submersible digital pump in an inefficient operating condition where active intervention can be applied. For example, appropriately reducing the rotational speed can reduce the inertial torque and mitigate vibration impact, thereby reducing power loss. If the bearing load abnormally increases, the bearing temperature will also abnormally increase. This application uses a second identification strategy to distinguish the correlation between abnormal operating efficiency and structural abnormalities, i.e., whether there is structural synergy in the efficiency deviation value. If so, the bearing load abnormality is confirmed, and active intervention can be carried out.

[0092] This application uses a first identification strategy and a second identification strategy to confirm whether a submersible digital pump is in an inefficient operating condition that can be actively intervened in, thereby improving the targeting of regulation and avoiding ineffective regulation. Existing control systems trigger speed adjustment to restore operating efficiency when abnormally low operating efficiency is detected. However, in the actual operation of submersible pumps, there are efficiency declines that do not require active intervention, such as power grid fluctuations and water pressure fluctuations at downstream users. These can all cause a decrease in the operating efficiency of the submersible pump. These efficiency declines are not caused by poor operating conditions of the submersible pump itself. In these cases, intervening in the speed or motor current cannot effectively restore operating efficiency, but may instead cause a disturbance amplification effect, resulting in over-adjustment or oscillation.

[0093] The strategy module is used to formulate efficiency adjustment strategies, including: setting adjustment cycles; calculating the efficiency density of each adjustment cycle based on the operating efficiency; and setting adjustment compensation factors based on the efficiency density.

[0094] The strategy module includes an efficiency identification unit and an adjustment compensation unit; wherein, the efficiency identification unit is used to set the adjustment period and calculate the efficiency density for each adjustment period; specifically, it includes:

[0095] The operational efficiency at each point in time is organized into a time series of operational efficiency in chronological order.

[0096] Set the cycle length of the adjustment period; divide the time series of operating efficiency into continuous adjustment periods based on the cycle length;

[0097] In this embodiment, the length of the adjustment cycle is represented by the number of time points included in the adjustment cycle; the length of each adjustment cycle is the same.

[0098] Each operating efficiency in each adjustment cycle is discretized to obtain the operating efficiency label at each time point in each adjustment cycle;

[0099] Optionally, the operating efficiency of the submersible digital pump can be divided into different value ranges; for example, if the interval length of each value range is set to 0.05, then two adjacent value ranges can be set to... , Number each range of operating efficiency; for any operating efficiency in any adjustment cycle, determine the range in which it falls and use the range number as its operating efficiency label.

[0100] For any adjustment cycle, count the number of times each operating efficiency label appears, and mark the operating efficiency label with the most occurrences as the dominant efficiency label;

[0101] The efficiency density of each adjustment cycle is calculated based on the dominant efficiency label; whereby the efficiency density of any adjustment cycle is the ratio of the number of occurrences of the dominant efficiency label to the cycle length.

[0102] Efficiency density reflects the concentration trend of operating efficiency during the adjustment cycle; the higher the efficiency density, the more obvious the concentration trend of operating efficiency, the more stable the operating state of the submersible digital pump, and the more suitable it is for aggressive adjustment.

[0103] The efficiency identification unit is also used to calculate the efficiency density gradient for each adjustment cycle, specifically including:

[0104] For any adjustment period, the absolute value of the difference between the number of occurrences of the dominant efficiency label and the number of occurrences of the dominant efficiency label in the adjacent previous adjustment period is calculated as the efficiency density change for the corresponding adjustment period; the ratio of the efficiency density change to the period length is calculated to obtain the efficiency density gradient.

[0105] The efficiency density gradient reflects the change in operating efficiency during the corresponding adjustment cycle. A large efficiency density gradient indicates significant fluctuations in operating efficiency, suggesting that the submersible digital pump is experiencing oscillations or is recovering on its own. In this case, a conservative adjustment strategy is appropriate.

[0106] The adjustment and compensation unit is used to set the adjustment and compensation factor, specifically including:

[0107] Set the value range of the adjustment compensation factor; the value range of the adjustment compensation factor can be set according to experience or experimental data, so that when the adjustment compensation factor is assigned any value in the value range, it can stably and effectively adjust the operating efficiency of the submersible digital pump.

[0108] Setting an adjustment compensation factor for each adjustment cycle; specifically, this includes: assigning a value to the adjustment compensation factor in the assigned range based on the efficiency density and efficiency density gradient of each adjustment cycle, wherein the magnitude of the efficiency density is positively correlated with the value of the adjustment compensation factor, and the magnitude of the efficiency density gradient is negatively correlated with the value of the adjustment compensation factor.

[0109] Existing control systems mostly adjust submersible digital pumps based on real-time operating efficiency, but changes in operating efficiency often exhibit flickering effects or instantaneous abnormal pulses. This application sets adjustment compensation factors based on efficiency density and efficiency density gradient, which can overcome the problem of over-response that is easily caused by directly using real-time operating efficiency as the adjustment basis in existing solutions.

[0110] The control module generates speed control commands based on the efficiency adjustment strategy, and adjusts the operating efficiency of the submersible digital pump in an inefficient operating condition based on the speed control commands.

[0111] The control module includes a speed calculation unit and a control command unit. The speed calculation unit calculates the speed adjustment amount based on the efficiency deviation value in each adjustment cycle. The control command unit adjusts and compensates the speed adjustment amount based on an adjustment compensation factor and generates a speed control command. Specifically, this includes calculating the product of the adjustment compensation factor and the speed adjustment amount as the adjusted and compensated speed adjustment amount, and generating a speed control command containing the speed adjustment amount. The control command unit sends the speed control command to the digital motor of the submersible digital pump. The digital motor adjusts the speed of the submersible digital pump based on the speed adjustment amount contained in the speed control command. By adjusting the speed, the flow rate and head of the submersible digital pump are indirectly changed, thereby changing the actual operating power of the submersible digital pump and maintaining its operating efficiency within a high range.

[0112] The speed calculation unit is equipped with a PID controller and calculates the speed adjustment based on the PID controller, specifically including:

[0113] The time series of the efficiency deviation value is input into the PID controller. The PID controller automatically calculates the derivative and integral of the efficiency deviation value over time, and calculates the speed adjustment based on the efficiency deviation value and its derivative and integral.

[0114] The speed regulation amount is the adjustment amount applied to the rotational speed of the rotor assembly in the digital motor. Data is collected through experiments or simulations to train the PID controller, enabling it to calculate the speed regulation amount that gradually brings the operating efficiency closer to the reference operating efficiency (i.e., brings the efficiency deviation value closer to 0) based on the deviation between the operating efficiency of the submersible digital pump and a reference operating efficiency (i.e., the efficiency deviation value) and its derivative and integral over time. The PID controller can achieve continuous tracking control of the efficiency deviation value. In this embodiment, the adjustment amount of the PID controller output is adjusted and compensated based on efficiency density, which enhances the PID controller's ability to adjust for nonlinear changes and uncertain trends in the efficiency deviation value.

[0115] Example 2

[0116] This embodiment is the second embodiment of this application; it is based on the same inventive concept as Embodiment 1, and refers to... Figure 3 This embodiment describes a submersible digital pump, including a pump head, a digital motor, and a digital control system as described in Embodiment 1; wherein:

[0117] The pump head is used for the intake, pressurization, and output of liquids;

[0118] The digital motor includes a winding core, a rotor assembly, an upper bearing, and a lower bearing, and is used to provide driving force for the operation of the pump head;

[0119] The digital control system monitors the operating efficiency of the pump head and the digital motor; if the pump head and the digital motor are operating inefficiently, the digital control system improves the operating efficiency by adjusting the speed of the rotor assembly in the digital motor. Figure 3 As shown, the digital control system uses thermistors installed at the winding core of the digital motor and at the upper and lower bearings to collect real-time status parameters such as winding temperature, upper bearing temperature, and lower bearing temperature, which serve as part of the data basis for monitoring the operating efficiency of the pump head and the digital motor.

[0120] Optionally, the pump head includes an outlet guide vane, an impeller, and a pump body inlet ring; the impeller rotates under the drive of a digital motor, applying kinetic energy to the liquid to achieve liquid intake and pressurization; the outlet guide vane is used to guide the liquid discharged by the impeller to the outlet to complete the liquid output; the pump body inlet ring and the impeller form a sealing fit to limit liquid backflow and improve the overall pressurization and sealing performance of the pump head.

[0121] like Figure 3As shown, the pump head also includes a cable welding block and a leakage probe; the cable welding block is used to install the cable and ensure that there are no gaps at the cable installation point to prevent water from entering the digital motor; the leakage probe is used to monitor whether the motor is leaking water. Sealing rings are provided at the pump body inlet ring and other parts to enhance sealing and prevent liquid leakage; impellers and other components are fixed with set screws to ensure the stability of the pump head structure.

[0122] Optionally, the digital motor adopts a permanent magnet synchronous motor design; after the winding core is energized, it generates a rotating magnetic field, which drives the rotor assembly to rotate; the rotor assembly generates torque under the action of the rotating magnetic field, which is used to drive the impeller in the pump head to rotate; the upper bearing and the lower bearing are used to support the rotating shaft of the rotor assembly, ensuring its mechanical stability and coaxiality during high-speed operation, and reducing vibration and wear.

[0123] like Figure 3 As shown, the digital motor also includes an upper mechanical seal, a lower mechanical seal, an oil lifter, and an exhaust port. Specifically, an upper mechanical seal is installed inside the water outlet guide vane to prevent external liquid from entering the digital motor. The outer periphery of the upper mechanical seal is an oil chamber, and the oil lifter lifts the mechanical oil in the oil chamber to continuously lubricate and cool the upper mechanical seal. A lower mechanical seal is installed at the impeller to prevent external liquid from entering the oil chamber. An exhaust port is provided inside the water outlet guide vane to promptly remove gas from the upper space of the impeller and prevent cavitation of the impeller.

[0124] The specific structure and function implementation of the digital control system are described in the relevant content of Example 1, and will not be repeated here.

[0125] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0126] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of protection of this application, and these forms are all within the protection scope of this application.

Claims

1. A digital control system, characterized in that: It includes a data acquisition module, a calculation module, a recognition module, a strategy module, and a control module; among which: The data acquisition module is used to collect the operating parameters and status parameters of the submersible digital pump; The calculation module calculates the operating efficiency and efficiency deviation value of the submersible digital pump based on the operating parameters; The operating parameters include speed, motor current, and motor voltage; the status parameters include winding temperature, upper bearing temperature, and lower bearing temperature. The calculation module includes a storage unit and a calculation unit; wherein, the storage unit is configured with the operating characteristic curves of the submersible digital pump at different speeds; the calculation unit calculates the operating efficiency and efficiency deviation value of the submersible digital pump based on the operating parameters and the operating characteristic curves; The operating characteristic curves include flow-power curves and flow-head curves; any flow-power curve is the curve showing the change of input power of the submersible digital pump with flow rate at the corresponding speed; any flow-head curve is the curve showing the change of head of the submersible digital pump with flow rate at the corresponding speed. The calculation of the operating efficiency of the submersible digital pump specifically includes: Calculate the current input power of the submersible digital pump based on the motor current and motor voltage; Based on the rotational speed, obtain the corresponding flow-power curve and flow-head curve; based on the flow-power curve, query the flow rate corresponding to the current input power to obtain the current flow rate; Based on the flow-head curve, query the head corresponding to the current flow rate to obtain the current head; Calculate the operating power of the submersible digital pump based on the current flow rate and current head; The operating efficiency of a submersible digital pump is calculated based on its operating power and current input power; wherein, the operating efficiency is the ratio of the submersible digital pump's operating power to its current input power. The storage unit is also configured with a reference operating efficiency and an efficiency deviation threshold for the submersible digital pump; the calculation unit calculates the efficiency deviation value of the submersible digital pump based on the operating efficiency and the reference operating efficiency; if the operating efficiency is greater than or equal to the reference operating efficiency, the efficiency deviation value is 0; otherwise, the efficiency deviation value is the difference between the reference operating efficiency and the operating efficiency; if the efficiency deviation value is greater than the efficiency deviation threshold for at least m consecutive time points, the calculation unit sends an identification command to the identification module to trigger the identification of the inefficient operating condition of the submersible digital pump; m is a positive integer; The identification module identifies the load responsiveness and structural coordination of efficiency deviation values ​​based on the operating parameters and status parameters, and identifies the inefficient operating conditions of the submersible digital pump based on the load responsiveness and structural coordination. If the efficiency deviation value exhibits at least one of the characteristics of load responsiveness and structural synergy, the submersible digital pump is operating in an inefficient condition. The identification module includes a first identification unit; the first identification unit is configured with a first identification strategy for identifying the load responsiveness of efficiency deviation values; the first identification strategy specifically includes: The efficiency deviation values ​​at each time point are arranged in chronological order to form a time series of efficiency deviation values. Organize the motor current at each time point into a time series of motor current; organize the winding temperature at each time point into a time series of winding temperature; Calculate the mean of all elements in the time series of motor current to obtain the average current; calculate the mean of all elements in the time series of winding temperature to obtain the average winding temperature; calculate the cross-correlation coefficient between the time series of motor current and winding temperature and the time series of efficiency deviation. The first identification unit is also configured with a current threshold, a winding temperature threshold, and a load correlation threshold; if the average current is greater than the current threshold, the average winding temperature is greater than the winding temperature threshold, and the cross-correlation coefficient is greater than the load correlation threshold, then the efficiency deviation value exhibits load responsiveness. The identification module further includes a second identification unit; the second identification unit is configured with a second identification strategy for identifying the structural synergy of efficiency deviation values; the second identification strategy specifically includes: Calculate the average of the upper and lower bearing temperatures at each time point, and use this as the bearing temperature at each time point; then arrange the bearing temperatures at each time point in chronological order to form a time series of bearing temperatures. The mean of all elements in the time series of bearing temperature is calculated as the average bearing temperature; the bearing temperature is predicted based on the time series of bearing temperature to obtain the predicted bearing temperature for at least n consecutive time points in the future; n is a positive integer; The second identification unit is also equipped with a bearing temperature threshold. If the average bearing temperature and the predicted bearing temperature at n time points are both greater than the bearing temperature threshold, then the efficiency deviation value exhibits structural synergy. The strategy module is used to formulate efficiency adjustment strategies, including: setting adjustment cycles; calculating the efficiency density of each adjustment cycle based on the operating efficiency; and setting adjustment compensation factors based on the efficiency density. The strategy module includes an efficiency identification unit and an adjustment compensation unit; wherein, the efficiency identification unit is used to set the adjustment period and calculate the efficiency density for each adjustment period; specifically, it includes: The operational efficiency at each point in time is organized into a time series of operational efficiency in chronological order. Set the cycle length of the adjustment period; divide the time series of operating efficiency into continuous adjustment periods based on the cycle length; Each operating efficiency in each adjustment cycle is discretized to obtain the operating efficiency label at each time point in each adjustment cycle; For any adjustment cycle, count the number of times each operating efficiency label appears, and mark the operating efficiency label with the most occurrences as the dominant efficiency label; The efficiency density of each adjustment cycle is calculated based on the dominant efficiency label; whereby the efficiency density of any adjustment cycle is the ratio of the number of occurrences of the dominant efficiency label to the cycle length. The control module generates speed control commands based on the efficiency adjustment strategy, and adjusts the operating efficiency of the submersible digital pump in an inefficient operating condition based on the speed control commands.

2. The digital control system as described in claim 1, characterized in that: The efficiency identification unit is also used to calculate the efficiency density gradient for each adjustment cycle, specifically including: For any adjustment period, calculate the absolute value of the difference between the number of occurrences of the dominant efficiency label and the number of occurrences of the dominant efficiency label in the adjacent previous adjustment period, and use it as the efficiency density change for the corresponding adjustment period; calculate the ratio of the efficiency density change to the period length to obtain the efficiency density gradient. The strategy module also includes an adjustment and compensation unit; The adjustment and compensation unit is used to set the adjustment and compensation factor, specifically including: Set the value range of the adjustment compensation factor; set the adjustment compensation factor for each adjustment period; specifically, based on the efficiency density and efficiency density gradient of each adjustment period, assign a value to the adjustment compensation factor in the value range, and the magnitude of the efficiency density is positively correlated with the value of the adjustment compensation factor, and the magnitude of the efficiency density gradient is negatively correlated with the value of the adjustment compensation factor.

3. A digital control system as described in claim 2, characterized in that: The control module includes a speed calculation unit and a control command unit. The speed calculation unit calculates the speed adjustment amount based on the efficiency deviation value in each adjustment cycle. The control command unit adjusts and compensates the speed adjustment amount based on an adjustment compensation factor and generates a speed control command. Specifically, this includes: calculating the product of the adjustment compensation factor and the speed adjustment amount as the adjusted and compensated speed adjustment amount, and generating a speed control command containing the speed adjustment amount. The control command unit sends the speed control command to the digital motor of the submersible digital pump, and the digital motor adjusts the speed of the submersible digital pump based on the speed adjustment amount contained in the speed control command. The speed calculation unit is equipped with a PID controller, and calculates the speed adjustment amount based on the PID controller. Specifically, it includes: inputting the time series of the efficiency deviation value into the PID controller, the PID controller automatically calculating the derivative and integral of the efficiency deviation value over time, and calculating the speed adjustment amount based on the efficiency deviation value and its derivative and integral.

4. A submersible digital pump, characterized in that: It includes a pump head, a digital motor, and a digital control system as described in any one of claims 1-3; wherein: The pump head is used for the intake, pressurization, and output of liquids; The digital motor includes a winding core, a rotor assembly, an upper bearing, and a lower bearing, and is used to provide driving force for the operation of the pump head; The digital control system is used to monitor the operating efficiency of the pump head and the digital motor; if the pump head and the digital motor are in an inefficient operating condition, the digital control system improves the operating efficiency by adjusting the speed of the rotor assembly in the digital motor.

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