Submersible digital pump and digital control system

Abstract

The invention relates to the technical field of submersible pumps, and discloses a submersible digital pump and a digital control system, the digital control system comprises a data acquisition module, a calculation module, an identification module, a strategy module and a control module; wherein the data acquisition module is used for acquiring operation parameters and state parameters of the submersible digital pump; the calculation module is used for calculating the operation efficiency and the efficiency deviation value of the submersible digital pump; the identification module is used for identifying the load responsiveness and the structure collaboration of the efficiency deviation value and identifying the low-efficiency operation condition of the submersible digital pump; the strategy module is used for formulating an efficiency adjustment strategy; and the control module generates a rotating speed control instruction based on the efficiency adjustment strategy, and adjusts the operation efficiency of the submersible digital pump in the low-efficiency operation condition based on the rotating speed control instruction. According to the application, intelligent identification and self-adaptive regulation and control of the operation efficiency of the submersible digital pump are realized, and the operation stability of the submersible digital pump is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of submersible pumps, in particular to a submersible digital pump and a digital control system. BACKGROUND

[0002] With the progress of motor control technology and sensor technology, traditional submersible pumps gradually evolve towards digitization, forming a submersible digital pump with a digital motor and a control system as the core. The digital motor has the characteristics of high responsiveness and high efficiency, and the digital control system provides more precise monitoring and control capabilities for the operating state of the submersible pump. However, the current control technology of submersible digital pumps still has some defects.

[0003] Most current digital control systems are based on operating parameters such as current, voltage, and speed, and lack system monitoring of the internal operating state and structural state of the submersible pump, resulting in the control system relying too much on surface data in the adjustment strategy and being difficult to determine whether the efficiency decline is caused by operating condition deviation or other irregular disturbances. This blind adjustment method is likely to trigger adjustment operations in unnecessary situations, leading to oscillation, over-regulation, increased energy consumption, and further inducing equipment damage. The traditional operating efficiency adjustment method usually takes the efficiency deviation at the current time as input, lacking overall understanding of the efficiency trend. In actual operation, the efficiency fluctuation often presents a short-period flickering or quasi-periodic pulse mode, which easily interferes with the adjustment algorithm, making the adjustment strategy not only unable to improve efficiency, but also likely to exacerbate system load.

[0004] Chinese patent application CN110529400A discloses a submersible pump control system and a control method thereof. The submersible pump includes a submersible pump working body fixed at the bottom of a pool, a suspended buoy device for suspending on the pool surface, an automatic range finder for controlling the power output of the submersible pump working body, a control module, a communication module for communication connection with a management client, and a management client. The scheme suspends the suspended buoy device on the pool surface to ensure that the automatic range finder measures effective pool water depth data, and then transmits the corresponding data to the management client through the communication module to achieve the purpose of real-time monitoring of the working condition of the submersible pump working body. When the management client directly controls the working state of the submersible pump working body through the control module, it effectively avoids the occurrence of idling, over-running, and low working efficiency of the submersible pump working body, and improves the working efficiency of the submersible pump. However, this scheme still has the problem mentioned in the background of the present application: lack of monitoring of the internal operating state and structural state of the submersible pump, which is likely to trigger adjustment operations in unnecessary situations.

[0005] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general background of the present application and does not necessarily constitute an acknowledgement or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the defects of the prior art, and provide a submersible digital pump and a digital control system, which realize intelligent identification and self-adaptive regulation and control of the operation efficiency of the submersible digital pump, and improve the operation stability of the submersible digital pump.

[0007] To solve the above technical problems, the present application provides the following technical solutions:

[0008] On the one hand, the present application provides a digital control system, which comprises a data acquisition module, a calculation module, an identification module, a strategy module and a control module; the functions of the modules are as shown in the accompanying drawings. Figure 2 Among them:

[0009] The data acquisition module is used for acquiring operation parameters and state parameters of the submersible digital pump;

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

[0011] The identification module identifies the load responsiveness and the structural cooperativity of the efficiency deviation value based on the operation parameters and the state parameters, and identifies the low-efficiency operation condition of the submersible digital pump based on the load responsiveness and the structural cooperativity;

[0012] The strategy module is used for formulating an efficiency adjustment strategy, which comprises: setting an adjustment period; calculating the efficiency density of each adjustment period based on the operation efficiency, and setting an adjustment compensation factor based on the efficiency density;

[0013] The control module generates a rotating speed control instruction based on the efficiency adjustment strategy, and adjusts the operation efficiency of the submersible digital pump in the low-efficiency operation condition based on the rotating speed control instruction.

[0014] As a preferred scheme of the digital control system described in the present application, wherein: the operation parameters comprise rotating speed, motor current and motor voltage; the state parameters comprise winding temperature, upper bearing temperature and lower bearing temperature;

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

[0016] The operation characteristic curve comprises a flow rate-power curve and a flow rate-head curve; any flow rate-power curve is a curve of input power of the submersible digital pump varying with flow rate at a corresponding rotating speed; and any flow rate-head curve is a curve of head of the submersible digital pump varying with flow rate at a corresponding rotating speed.

[0017] As a preferred scheme of the digital control system described in the application, the calculating of the operation efficiency of the submersible digital pump specifically comprises:

[0018] The input power of the submersible digital pump at present is calculated based on the motor current and the motor voltage;

[0019] The corresponding flow rate-power curve and flow rate-head curve are obtained based on the rotating speed; the flow rate corresponding to the current input power is obtained by inquiring the flow rate-power curve;

[0020] The head corresponding to the current flow rate is obtained by inquiring the flow rate-head curve, to obtain the current head;

[0021] The operation power of the submersible digital pump is calculated based on the current flow rate and the current head;

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

[0023] As a preferred scheme of the digital control system described in the application, the storage unit is further configured with a reference operation efficiency of the submersible digital pump and an efficiency deviation threshold value; the calculating unit calculates an efficiency deviation value of the submersible digital pump based on the operation efficiency and the reference operation efficiency; if the operation efficiency is greater than or equal to the reference operation efficiency, the efficiency deviation value is 0; otherwise, the efficiency deviation value is the difference between the reference operation efficiency and the operation efficiency; if the efficiency deviation values of at least m consecutive time points are greater than the efficiency deviation threshold value, the calculating unit sends an identification instruction to the identification module to trigger identification of the low-efficiency operation condition of the submersible digital pump; m is a positive integer.

[0024] As a preferred scheme of the digital control system described in the application, if the efficiency deviation value has at least one of load responsiveness and structural synergy, the submersible digital pump is in a low-efficiency operation condition;

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

[0026] The efficiency deviation values of each time point are arranged in time sequence into a time sequence of efficiency deviation values;

[0027] arranging the motor current of each time point into a time sequence of motor current, and arranging the winding temperature of each time point into a time sequence of winding temperature;

[0028] calculating the mean value of all elements in the time sequence of motor current to obtain an average current, calculating the mean value of all elements in the time sequence of winding temperature to obtain an average winding temperature, and calculating the cross-correlation coefficient between the time sequence of any one of the motor current and the winding temperature and the time sequence of the efficiency deviation value;

[0029] The first identification unit is further 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, the efficiency deviation value has load responsiveness.

[0030] As a preferred scheme of the digital control system described in the present application, the identification module further comprises a second identification unit, the second identification unit is configured with a second identification strategy for identifying structural synergy of the efficiency deviation value, and the second identification strategy specifically comprises:

[0031] calculating the mean value of the upper bearing temperature and the lower bearing temperature of each time point as the bearing temperature of each time point, and arranging the bearing temperature of each time point in time sequence into a time sequence of bearing temperature;

[0032] calculating the mean value of all elements in the time sequence of bearing temperature as an average bearing temperature, predicting the bearing temperature based on the time sequence of bearing temperature to obtain the predicted value of the bearing temperature of at least n consecutive time points in the future, and n is a positive integer;

[0033] The second identification unit is further configured with a bearing temperature threshold. If the average bearing temperature and the predicted value of the bearing temperature of n time points are both greater than the bearing temperature threshold, the efficiency deviation value has structural synergy.

[0034] As a preferred scheme of the digital control system described in the present application, the strategy module comprises an efficiency identification unit and an adjustment compensation unit. The efficiency identification unit is used to set an adjustment period and calculate the efficiency density of each adjustment period. Specifically, the efficiency identification unit comprises:

[0035] arranging the operating efficiency of each time point in time sequence into a time sequence of operating efficiency;

[0036] setting the cycle length of the adjustment period, and dividing the time sequence of operating efficiency into continuous adjustment periods based on the cycle length;

[0037] discretizing each operating efficiency in each adjustment period to obtain the operating efficiency label of each time point in each adjustment period.

[0038] For any adjustment period, the number of occurrences of each operating efficiency label is counted, and the operating efficiency label with the most occurrences is marked as the dominant efficiency label;

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

[0040] As a preferred scheme of the digital control system described in the present application, wherein: the efficiency identification unit is further configured to calculate the efficiency density gradient of each adjustment period, specifically comprising:

[0041] 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 of the corresponding adjustment period; the ratio of the efficiency density change to the length of the period is calculated to obtain the efficiency density gradient;

[0042] The strategy module further comprises an adjustment compensation unit;

[0043] The adjustment compensation unit is configured to set an adjustment compensation factor, specifically comprising:

[0044] An assignment interval of the adjustment compensation factor is set; the adjustment compensation factor is set for each adjustment period; specifically comprising: based on the efficiency density and the efficiency density gradient of each adjustment period, the adjustment compensation factor is assigned in the assignment interval, and the size of the efficiency density is positively correlated with the value of the adjustment compensation factor, and the size of the efficiency density gradient is negatively correlated with the value of the adjustment compensation factor.

[0045] As a preferred scheme of the digital control system described in the present application, wherein: the control module comprises a speed calculation unit and a control instruction unit; wherein the speed calculation unit is configured to calculate a speed adjustment amount based on the efficiency deviation value in each adjustment period; the control instruction unit adjusts the speed adjustment amount based on the adjustment compensation factor and generates a speed control instruction; specifically comprising: calculating the product of the adjustment compensation factor and the speed adjustment amount as the speed adjustment amount after adjustment compensation, and generating a speed control instruction containing the speed adjustment amount; the control instruction unit sends the speed control instruction 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 instruction;

[0046] The speed calculation unit is configured with a PID controller, and the speed adjustment amount is calculated based on the PID controller, specifically comprising: inputting the time series of the efficiency deviation value into the PID controller, and the PID controller automatically calculates the derivative and integral of the efficiency deviation value over time, and calculates the speed adjustment amount based on the efficiency deviation value and its derivative and integral.

[0047] In a second aspect, the application provides a submersible digital pump, comprising a pump head, a digital motor, and a digital control system as described in the application; wherein:

[0048] The pump head is used for liquid suction, pressurization and output;

[0049] The digital motor comprises 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 a low-efficiency operating condition, the digital control system adjusts the rotating speed of the rotor assembly in the digital motor to improve the operating efficiency.

[0051] Compared with the prior art, the application has the following beneficial effects:

[0052] The application can trigger corresponding adjustment actions when the pump body is in a low-efficiency operating condition by real-time monitoring and intelligent control of the operating state of the submersible digital pump, thereby effectively improving the operating efficiency of the submersible digital pump and improving the self-adaptive ability of the digital pump under different loads and operating conditions.

[0053] The application can distinguish between real efficiency decline caused by pump body operating condition deterioration and abnormal efficiency fluctuation caused by external disturbance, avoid unnecessary adjustment operations caused by misjudgment, and reduce adjustment shock risk.

[0054] The application dynamically evaluates the stability and change trend of the operating efficiency through efficiency density and efficiency density gradient, and realizes flexible adjustment compensation, thereby enhancing the intelligent level and efficiency adjustment ability of the submersible digital pump. BRIEF DESCRIPTION OF DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0056] Figure 1 A structural schematic diagram of a digital control system provided by the application;

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

[0058] Figure 3 A structural schematic diagram of a submersible digital pump provided by the application. DETAILED DESCRIPTION

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

[0060] Embodiment 1

[0061] This embodiment introduces a digital control system, which refers to Figure 1 The system comprises a data acquisition module, a calculation module, an identification module, a strategy module, and a control module, wherein:

[0062] The data acquisition module is used to acquire the operating parameters and state parameters of the submersible digital pump.

[0063] The data acquisition module comprises an operating monitoring unit and a state monitoring unit. The operating monitoring unit is used to acquire the operating parameters of the submersible digital pump. The operating parameters include the rotational speed, motor current, and motor voltage. The rotational speed is the rotational speed of the rotor assembly of the digital motor in the submersible digital pump.

[0064] The state monitoring unit is used to acquire the state parameters of the submersible digital pump. The state parameters include the winding temperature, upper bearing temperature, and lower bearing temperature. The state monitoring unit is configured with thermistors installed at the winding core of the digital motor in the submersible digital pump and at the upper bearing and lower bearing, and can acquire the state parameters including the winding temperature, upper bearing temperature, and lower bearing temperature in real time.

[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 comprises a storage unit and a calculation unit. The storage unit is configured with operating characteristic curves of the submersible digital pump at different rotational 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 the flow rate-power curve and the flow rate-lift curve. Any flow rate-power curve is a curve of the input power of the submersible digital pump varying with the flow rate at a corresponding rotational speed. Each point on the flow rate-power curve corresponds to a flow rate and an input power, indicating the input power required by the submersible digital pump to maintain the corresponding flow rate. The greater the flow rate, the greater the water resistance, and the submersible digital pump needs greater input power to drive the impeller to overcome the resistance.

[0067] Any flow rate-lift curve is a curve of the lift of the submersible digital pump varying with the flow rate at a corresponding rotational speed. Each point in the flow rate-lift curve corresponds to a flow rate and a lift, indicating the size of the lift output by the submersible digital pump at the corresponding flow rate.

[0068] The operation efficiency of the submersible digital pump is calculated, specifically including:

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

[0070] The corresponding flow power curve and flow head curve are obtained based on the rotational speed; the current flow is obtained by querying the flow power curve corresponding to the current input power;

[0071] The current head is obtained by querying the flow head curve corresponding to the current flow;

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

[0073] ;

[0074] Wherein, P represents the operation power, represents the liquid density, g represents the gravitational acceleration; Q represents the current flow; H represents the current head.

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

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

[0077] The identification module identifies the load responsiveness and structural synergy of the efficiency deviation value based on the operation parameters and the state parameters, and identifies the low-efficiency operation condition of the submersible digital pump based on the load responsiveness and the structural synergy;

[0078] If the efficiency deviation value has at least one of the load responsiveness and the structural synergy, the submersible digital pump is in a low-efficiency operation 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 the efficiency deviation value; the first identification strategy specifically includes:

[0080] arranging the efficiency deviation values at each time point in time sequence to form a time sequence of efficiency deviation values;

[0081] arranging the motor current at each time point in time sequence to form a time sequence of motor current; arranging the winding temperature at each time point in time sequence to form a time sequence of winding temperature;

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

[0083] Optionally, the cross-correlation coefficient between the time sequence of motor current or winding temperature and the time sequence of efficiency deviation value at different lag times is calculated based on the cross-correlation function, and a lag time window is set to take the maximum cross-correlation coefficient at all lag times in the lag time window. The lag time window is set based on experimental data or experience, for limiting the value range of lag time, preventing the lag time from being too large, causing the cross-correlation coefficient to lose practical significance and unable to reflect the correlation between the running efficiency decline and the increase of 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, the efficiency deviation value has load responsiveness.

[0085] When the electromagnetic load of the submersible digital pump increases, for example, the water inlet is blocked, the content of liquid impurities increases, etc., it will cause the running power to rise but the flow to decrease, the running efficiency to be low, and the submersible digital pump to be in a low-efficiency running condition that can be actively intervened; for example, appropriately reducing the speed can reduce the load, reduce the shear loss of the transported liquid, avoid overloading of the digital motor, and restore the running efficiency to the expected level. If the electromagnetic load increases, the motor current increases, causing the winding temperature to increase synchronously; the present application distinguishes the running efficiency anomaly caused by the increase of electromagnetic load through the first identification strategy, that is, distinguishes whether the efficiency deviation value has load responsiveness, and if so, confirms that the electromagnetic load is heavy, and active intervention can be performed.

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

[0087] calculating the mean value of the upper bearing temperature and the lower bearing temperature at each time point as the bearing temperature at each time point; arranging the bearing temperature at each time point in time sequence to form a time sequence of bearing temperature;

[0088] calculating a mean value of all elements in the time sequence of the bearing temperature as an average bearing temperature; predicting the bearing temperature based on the time sequence of the bearing temperature to obtain predicted values of the bearing temperature at at least n continuous future time points; n is a positive integer;

[0089] Optionally, the second identification unit is configured with a trained time series prediction model, and the time series prediction model 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 sequence of the bearing temperature based on the time series prediction model to obtain the predicted value of the bearing temperature.

[0090] The second identification unit is also configured with a bearing temperature threshold value, and if the average bearing temperature and the predicted values of the bearing temperature at the n time points are all greater than the bearing temperature threshold value, the efficiency deviation value has structural synergy.

[0091] When the submersible digital pump has structural abnormalities such as impeller wear and insufficient bearing lubrication, the rotor assembly will be deflected or blocked, causing the bearing friction and vibration to intensify, resulting in mechanical loss of operating power, and the submersible digital pump is in a low-efficiency operating condition that can be actively intervened; for example, appropriately reducing the rotating speed can reduce the inertial torque and reduce the vibration impact, thereby reducing the power loss. If the bearing load abnormally increases, the bearing temperature will also abnormally increase; the present application distinguishes the correlation between the operating efficiency anomaly and the structural anomaly through the second identification strategy, i.e., whether the efficiency deviation value has structural synergy, and if so, it is confirmed that the bearing load is abnormal, and active intervention can be performed.

[0092] The present application confirms whether the submersible digital pump is in a low-efficiency operating condition that can be actively intervened through the first identification strategy and the second identification strategy, which can improve the pertinence of adjustment and avoid ineffective adjustment. The existing control system reaches the rotating speed adjustment to restore the operating efficiency when monitoring that the operating efficiency is abnormally low. However, in the actual operation of the submersible pump, there are efficiency decreases that do not require active intervention, such as power grid fluctuations and downstream user end water pressure fluctuations, which will cause the operating efficiency of the submersible pump to decrease. These efficiency decreases are not caused by poor operating conditions of the submersible pump itself, and at this time, applying intervention to the rotating speed or motor current cannot effectively restore the operating efficiency, but will cause a disturbance amplification effect, causing over-regulation or oscillation.

[0093] The strategy module is used to formulate an efficiency adjustment strategy, including: setting an adjustment period; calculating an efficiency density of each adjustment period based on the operating efficiency, and setting an adjustment compensation factor 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 an adjustment period and calculate an efficiency density of each adjustment period; specifically including:

[0095] arranging the running efficiencies at each time point in time sequence into a time sequence of running efficiencies;

[0096] setting a cycle length of the adjustment cycle; and dividing the time sequence of running efficiencies into continuous adjustment cycles based on the cycle length;

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

[0098] discretizing each running efficiency in each adjustment cycle to obtain a running efficiency label of each time point in each adjustment cycle;

[0099] Optionally, the running efficiency of the submersible digital pump is divided into different value intervals; for example, if the interval length of each value interval is set to 0.05, two adjacent value intervals can be set as , Each value interval of the running efficiency is numbered; for any running efficiency in any adjustment cycle, the value interval in which the running efficiency is located is determined, and the number of the value interval is taken as the running efficiency label of the running efficiency.

[0100] For any adjustment cycle, the number of occurrences of each running efficiency label is counted, and the running efficiency label with the largest number of occurrences is marked as a dominant efficiency label.

[0101] The efficiency density of each adjustment cycle is calculated based on the dominant efficiency label; wherein 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] The efficiency density reflects the concentration trend of the running efficiency in the adjustment cycle; the greater the efficiency density, the more obvious the concentration trend of the running efficiency, the more stable the running state of the submersible digital pump, and the more suitable for aggressive adjustment.

[0103] The efficiency identification unit is also configured to calculate the efficiency density gradient of each adjustment cycle, and specifically includes:

[0104] For any adjustment cycle, 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 cycle is calculated as the efficiency density change of the corresponding adjustment cycle; and the ratio of the efficiency density change to the cycle length is calculated to obtain the efficiency density gradient.

[0105] The efficiency density gradient reflects the change of the running efficiency in the corresponding adjustment cycle. The greater the efficiency density gradient, the more significant the fluctuation of the running efficiency, the more the running state of the submersible digital pump is in shock or is recovering itself, and thus it is suitable to execute a conservative adjustment strategy.

[0106] The adjustment compensation unit is configured to set an adjustment compensation factor, and specifically comprises:

[0107] An assignment interval of the adjustment compensation factor is set. The assignment interval of the adjustment compensation factor can be set according to experience or experimental data, so that when the adjustment compensation factor is assigned as any value in the assignment interval, the operation efficiency of the submersible digital pump can be stably and effectively adjusted.

[0108] The adjustment compensation factor is set for each adjustment period. Specifically, the adjustment compensation factor is assigned in the assignment interval based on the efficiency density and the efficiency density gradient of each adjustment period, and the size of the efficiency density is positively correlated with the value of the adjustment compensation factor, and the size of the efficiency density gradient is negatively correlated with the value of the adjustment compensation factor.

[0109] The existing control system adjusts the submersible digital pump based on the real-time operation efficiency, but the operation efficiency change often has a stroboscopic effect or a transient abnormal pulse. The adjustment compensation factor is set based on the efficiency density and the efficiency density gradient in the present application, which can overcome the problem that the real-time operation efficiency is directly used as the adjustment basis in the existing scheme, which is easy to over-respond.

[0110] The control module generates a speed control instruction based on the efficiency adjustment strategy, and adjusts the operation efficiency of the submersible digital pump in the low-efficiency operation condition based on the speed control instruction.

[0111] The control module comprises a speed calculation unit and a control instruction unit. The speed calculation unit is configured to calculate a speed adjustment amount based on an efficiency deviation value in each adjustment period. The control instruction unit adjusts and compensates the speed adjustment amount based on the adjustment compensation factor, and generates a speed control instruction. Specifically, the product of the adjustment compensation factor and the speed adjustment amount is calculated as the speed adjustment amount after adjustment and compensation, and a speed control instruction containing the speed adjustment amount is generated. The control instruction unit sends the speed control instruction 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 instruction. By adjusting the speed, the flow and the head of the submersible digital pump are indirectly changed, so that the actual operation power of the submersible digital pump is changed, and the operation efficiency of the submersible digital pump can be kept in a higher interval.

[0112] The speed calculation unit is configured with a PID controller, and the speed adjustment amount is calculated based on the PID controller. Specifically, the PID controller is configured to:

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

[0114] The speed adjustment amount is the adjustment amount applied to the speed of the rotor assembly in the digital motor. By collecting data through experiments or simulations to train the PID controller, the PID controller can calculate the speed adjustment amount that gradually brings the operating efficiency closer to the reference operating efficiency (i.e., the efficiency deviation value) based on the deviation between the operating efficiency of the submersible digital pump and the reference operating efficiency (i.e., the efficiency deviation value) and its differential and integral over time. The PID controller can achieve continuous tracking control of the efficiency deviation value; the embodiment of the present application adjusts and compensates the adjustment amount output by the PID controller based on the efficiency density, which can enhance the PID controller's ability to adjust to nonlinear changes and uncertain trends in the efficiency deviation value.

[0115] Example 2

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

[0117] The pump head is used for sucking, pressurizing and outputting liquid;

[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 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 state, 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 collects state parameters such as winding temperature, upper bearing temperature, and lower bearing temperature in real time through thermistors set at the winding core of the digital motor and the upper bearing and lower bearing, 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 a water outlet guide vane, an impeller, and a pump body mouth ring; the impeller rotates under the drive of a digital motor, applying kinetic energy to the liquid to achieve liquid suction and pressurization; the water outlet guide vane is used to guide the liquid discharged by the impeller to flow to the water outlet, completing the output of the liquid; a sealing fitting relationship is formed between the pump body mouth ring and the impeller, which is used to limit liquid reflux and improve the overall pressurization performance and sealing performance of the pump head.

[0121] like Figure 3As shown, the pump head further comprises a cable welding block and a water leakage probe; the cable welding block is used for installing the cable and ensuring that there is no gap at the cable installation position to prevent the digital motor from being waterlogged; the water leakage probe is used for monitoring whether the motor leaks water. A sealing ring is arranged at the pump body mouth ring and other positions to enhance the sealing property and prevent liquid leakage; the impeller and other components are fixed by a set screw to ensure the stability of the pump head structure.

[0122] Optionally, the digital motor adopts a permanent magnet synchronous motor design; the winding iron core generates a rotating magnetic field after being electrified to drive the rotor assembly to rotate; the rotor assembly generates torque under the action of the rotating magnetic field to drive the impeller in the pump head to rotate; the upper bearing and the lower bearing are used for supporting the rotating shaft of the rotor assembly to ensure the mechanical stability and coaxiality thereof during high-speed operation and reduce vibration and wear.

[0123] As shown in Figure 3 The digital motor further comprises an upper motor seal, a lower motor seal, an oil lifting device and an exhaust hole; specifically, the upper motor seal is arranged inside the water outlet guide vane to prevent external liquid from entering the inside of the digital motor; the periphery of the upper motor seal is an oil cavity, and the mechanical oil in the oil cavity is lifted by the oil lifting device to continuously lubricate and cool the upper motor seal; the lower motor seal is installed at the impeller to prevent external liquid from entering the oil cavity; the exhaust hole is arranged inside the water outlet guide vane to timely exhaust the gas in the space above the impeller to prevent the impeller from being subjected to cavitation.

[0124] The specific structure and function implementation of the digital control system refer to the related contents in Embodiment 1, and will not be described herein.

[0125] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can adopt a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0126] The embodiments of the present application are described above with reference to the drawings, but the present application is not limited to the above-described specific embodiments, and the above-described specific embodiments are only illustrative but not limiting, and those skilled in the art can make many forms under the inspiration of the present application without departing from the purpose and the protected scope of the present application, and these all belong to the protection of the present application.

Claims

1. A digital control system, characterized in that: It includes data acquisition module, calculation module, identification module, strategy module and 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 the efficiency deviation value of the submersible digital pump based on the operating parameters; The identification module identifies the load responsiveness and structural coordination of the efficiency deviation value based on the operating parameters and the state parameters, and identifies the inefficient operating condition of the submersible digital pump based on the load responsiveness and the structural coordination; The strategy module is used to formulate an efficiency adjustment strategy, including: setting an adjustment cycle; calculating the efficiency density of each adjustment cycle based on the operating efficiency, and setting an adjustment compensation factor based on the efficiency density; The control module generates a speed control instruction based on the efficiency adjustment strategy, and adjusts the operating efficiency of the submersible digital pump in a low-efficiency operating condition based on the speed control instruction.

2. A digital control system according to claim 1, characterized in that: The operating parameters include speed, motor current, and motor voltage; the state 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 an operating characteristic curve 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 curve; The operating characteristic curve includes a flow-power curve and a flow-head curve; any flow-power curve is a curve showing that the input power of the submersible digital pump changes with the flow rate at the corresponding speed; any flow-head curve is a curve showing that the head of the submersible digital pump changes with the flow rate at the corresponding speed.

3. A digital control system according to claim 2, characterized in that: The calculation of the operating efficiency of the submersible digital pump specifically includes: Calculating the current input power of the submersible digital pump based on the motor current and the motor voltage; Based on the speed, a corresponding flow-power curve and a flow-head curve are obtained; based on the flow-power curve, a flow corresponding to the current input power is queried to obtain the current flow; Based on the flow-head curve, query the head corresponding to the current flow and 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 the submersible digital pump is calculated based on the operating power of the submersible digital pump and the current input power; wherein the operating efficiency is the ratio of the operating power of the submersible digital pump to the current input power.

4. A digital control system according to claim 3, characterized in that: The storage unit is further configured with a reference operating efficiency and an efficiency deviation threshold of 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 at at least m consecutive time points is greater than the efficiency deviation threshold, the calculation unit sends an identification instruction to the identification module to trigger the identification of the inefficient operating condition of the submersible digital pump; m is a positive integer.

5. A digital control system according to claim 4, characterized in that: If the efficiency deviation value has at least one of load responsiveness and structural coordination, the submersible digital pump is in an inefficient operating 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 the efficiency deviation value; The first identification strategy specifically includes: Arrange the efficiency deviation value at each time point into a time series of efficiency deviation values ​​in chronological order; Arrange the motor current at each time point into a time series of the motor current; Arrange the winding temperature at each time point into a time series of the winding temperature; Calculate the mean of all elements in the time series of the motor current to obtain the average current; calculate the mean of all elements in the time series of the winding temperature to obtain the average winding temperature; calculate the correlation coefficient between the time series of any one of the motor current and winding temperature and the time series of the efficiency deviation value; The first identification unit is further configured with a current threshold, a winding temperature threshold, and a load correlation threshold; if the average current is greater than the current threshold, and the average winding temperature is greater than the winding temperature threshold, and the correlation coefficient is greater than the load correlation threshold, then the efficiency deviation value is load responsive.

6. A digital control system according to claim 5, characterized in that: 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 the efficiency deviation value; The second identification strategy specifically includes: Calculate the average of the upper bearing temperature and the lower bearing temperature at each time point as the bearing temperature at each time point; organize the bearing temperatures at each time point into a time series of bearing temperatures in chronological order; Calculating the mean of all elements in the time series of the bearing temperature as the average bearing temperature; predicting the bearing temperature based on the time series of the bearing temperature to obtain predicted values ​​of the bearing temperature for at least n consecutive time points in the future, where n is a positive integer; The second identification unit is further configured with a bearing temperature threshold. If the average bearing temperature and the predicted values ​​of the bearing temperatures at n time points are both greater than the bearing temperature threshold, the efficiency deviation value has structural synergy.

7. A digital control system according to claim 6, characterized in that: The strategy module includes an efficiency identification unit and an adjustment compensation unit; wherein the efficiency identification unit is used to set an adjustment cycle and calculate the efficiency density of each adjustment cycle; specifically, it includes: Arrange the operating efficiency at each time point into a time series of operating efficiency in chronological order; Set the cycle length of the adjustment cycle; divide the time series of the operating efficiency into consecutive adjustment cycles based on the cycle length; Discretize each operating efficiency in each adjustment cycle to obtain the operating efficiency label at each time point in each adjustment cycle; For any adjustment period, count the number of occurrences of each operating efficiency label, 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; wherein the efficiency density of any adjustment cycle is the ratio of the number of occurrences of the dominant efficiency label to the cycle length.

8. A digital control system according to claim 7, characterized in that: The efficiency identification unit is also used to calculate the efficiency density gradient of each adjustment cycle, including: For any adjustment cycle, 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 previous adjacent adjustment cycle is calculated as the efficiency density change of the corresponding adjustment cycle; the ratio of the efficiency density change to the cycle length is calculated to obtain the efficiency density gradient; The strategy module also includes an adjustment and compensation unit; The adjustment compensation unit is used to set the adjustment compensation factor, specifically including: Setting an assignment interval for the adjustment compensation factor; setting the adjustment compensation factor for each adjustment cycle; specifically including: assigning a value to the adjustment compensation factor within the assignment interval based on the efficiency density and efficiency density gradient of each adjustment cycle, and the size of the efficiency density is positively correlated with the value of the adjustment compensation factor, and the size of the efficiency density gradient is negatively correlated with the value of the adjustment compensation factor.

9. A digital control system according to claim 8, characterized in that: The control module includes a speed calculation unit and a control instruction unit; wherein the speed calculation unit is used to calculate the speed adjustment amount based on the efficiency deviation value in each adjustment cycle; the control instruction unit adjusts and compensates the speed adjustment amount based on the adjustment compensation factor and generates a speed control instruction; specifically, the steps include: calculating the product of the adjustment compensation factor and the speed adjustment amount as the speed adjustment amount after adjustment and compensation, and generating a speed control instruction including the speed adjustment amount; the control instruction unit sends the speed control instruction 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 included in the speed control instruction; The speed calculation unit is configured with a PID controller and calculates the speed adjustment amount based on the PID controller, specifically including: inputting the time series of the efficiency deviation value into the PID controller, the PID controller automatically calculating the differential and integral of the efficiency deviation value over time, and calculating the speed adjustment amount based on the efficiency deviation value and its differential and integral.

10. A submersible digital pump, characterized in that: The device comprises a pump head, a digital motor, and a digital control system according to any one of claims 1 to 9; wherein: The pump head is used for sucking, pressurizing and outputting liquid; 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 rotational speed of the rotor assembly in the digital motor.

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