Automatic water pump control strategy and energy efficiency optimization method and system

Abstract

The invention relates to the technical field of variable frequency speed regulation, in particular to an automatic water pump control strategy and energy efficiency optimization method and system.The method comprises the following steps of obtaining water pump outlet flow data, calculating flow acceleration, determining the pressure gradient direction, matching the hydraulic power trend, calculating frequency instruction deviation and setting the adjustable range; lagging and current rising mark inertia disturbance, power frequency limitation is set, a compensation value is generated, the frequency rate is dynamically adjusted in combination with all factors, and the frequency conversion adjusting priority is generated. According to the method, through matching of the flow acceleration and the pressure gradient, the sensing capacity for dynamic changes of fluid is improved, frequency adjustment of a frequency converter is optimized in combination with frequency deviation calculation, energy consumption increase caused by lag is reduced, and based on correlation analysis of the motor rotating speed change rate and current fluctuation, inertia disturbance accurate recognition is achieved; the voltage compensation timeliness is improved by combining bus voltage dynamic monitoring and a reverse compression strategy, the frequency of the frequency converter is dynamically adjusted by combining multiple parameters, and the response speed and the energy efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of variable frequency speed regulation, and in particular to an automated water pump control strategy and energy efficiency optimization method and system. Background Art

[0002] The field of variable frequency speed regulation encompasses a system of technologies that regulate pump speed by changing the motor input frequency through power electronic devices. The core technology in this area involves using a frequency converter to adjust the frequency-voltage characteristics of the pump's drive motor, optimizing system energy efficiency by reconstructing the operating range of the pump's head-flow curve. Its technical architecture comprises a closed-loop control system consisting of a pressure sensor network, flow detection devices, an embedded controller, and a variable frequency actuator. This encompasses algorithm design for dynamic pump speed regulation, multi-physical quantity feedback compensation mechanisms, and power loss optimization models. Its applications include fluid transport scenarios such as building water supply, industrial circulation, and agricultural irrigation.

[0003] The automated water pump control strategy and energy efficiency optimization method refers to a technical solution that achieves energy consumption control by matching water pump operating parameters with the dynamic demands of the pipeline network. This method specifically includes frequency converter frequency compensation adjustment technology based on pipeline pressure fluctuations, constructing a pipeline network load prediction model using combined feedback data from pressure sensors and flow meters, and combining a PID algorithm to perform real-time corrections to the frequency converter output waveform parameters. Furthermore, cross-validation of multi-sensor data eliminates single-point measurement deviations, maintaining the water pump operating point within a preset efficiency range.

[0004] Existing technologies rely on a single pressure or flow feedback for frequency adjustment in variable frequency speed control, resulting in a lag in adjustment when the pipe network load suddenly changes, and an inability to quickly adapt to dynamic changes. This can easily cause the pump operating point to deviate from the optimal operating area, leading to increased energy consumption and increased equipment losses. The identification of inertia disturbances relies on a single signal of current or speed, and lacks a comprehensive judgment of motor load fluctuations, resulting in a lag in system adjustment when the load suddenly increases, which may cause the motor to overload or frequently start and stop. The bus voltage compensation strategy is based on fixed parameter settings and fails to make dynamic adjustments based on the actual operating status, resulting in insufficient compensation when the voltage drops, affecting equipment stability. Under complex hydraulic conditions, the inverter's adjustment strategy is difficult to take into account hydraulic characteristics, load requirements, and electrical stability at the same time, resulting in insufficient system responsiveness and reduced overall operating efficiency. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an automated water pump control strategy and energy efficiency optimization method and system.

[0006] In order to achieve the above objectives, the present invention adopts the following technical solution: an automated water pump control strategy and energy efficiency optimization method, comprising the following steps:

[0007] S1: Obtain the instantaneous flow data of the pump outlet pipe section, calculate the flow acceleration, determine the pressure gradient direction of the adjacent pipe section nodes, and generate the hydraulic trend determination result by cross-matching the flow acceleration and the pressure gradient direction;

[0008] S2: Based on the hydraulic trend determination result, the deviation between the current inverter output frequency command and the reference stable frequency is calculated, and the maximum adjustable frequency range within the period is set. If the frequency change rate exceeds the set ratio, the frequency adjustment is triggered to generate the inverter frequency correction value;

[0009] S3: Calling the inverter frequency correction value, calculating the motor speed change rate, and comparing it with the inverter output frequency increment. If the speed lags and the motor current continues to rise, it is marked as inertia disturbance, and the inverter power upper limit and the inverter maximum frequency change range are set to generate the inertia compensation power limit value;

[0010] S4: Based on the inertia compensation power limit value, the change amplitude of the DC bus voltage is calculated. If the bus voltage drops by more than the set ratio and recovers with lag, the change between the current inverter frequency and the set average frequency is calculated. If the change is positive, reverse compression is performed to generate the bus voltage compensation frequency adjustment value.

[0011] As a further solution of the present invention, the hydraulic trend judgment result includes flow change trend, pressure gradient direction, and hydraulic stability; the inverter frequency correction value includes frequency increment, frequency decrement, and frequency stability adjustment; the inertia compensation power limit value includes maximum power limit, frequency change constraint, and current upper limit setting; the bus voltage compensation frequency adjustment value includes voltage compensation increment, frequency adjustment amplitude, and reverse compression ratio.

[0012] As a further solution of the present invention, the specific steps of S1 are:

[0013] S101: Obtain instantaneous flow data of the water pump outlet pipe section, call the instantaneous flow values at adjacent moments, calculate the flow rate change rate within adjacent time intervals, calculate the flow acceleration based on the ratio of the flow rate change rate to the time interval, extract the change trend in the time series based on the calculated flow acceleration, and obtain the flow acceleration value;

[0014] S102: Based on the flow acceleration value, pressure data of adjacent pipe segment nodes are obtained, the pressure values of the adjacent nodes are called, and the pressure difference between the adjacent nodes is calculated. Based on the length of the pipe segment, the pressure gradient per unit length is calculated. Based on the calculated pressure gradient, the directionality of the pressure gradient is determined to obtain pressure gradient direction data.

[0015] S103: Call the flow acceleration value and the pressure gradient direction data, cross-match the directionality of the two, determine whether the direction of the flow acceleration is consistent with the pressure gradient direction, classify the trend of the hydraulic state based on the matching result, and obtain a hydraulic trend determination result.

[0016] As a further solution of the present invention, the specific steps of S2 are:

[0017] S201: Based on the hydraulic trend determination result, the current inverter output frequency command and the reference stable frequency are obtained, the offset between the two is calculated, the maximum adjustable frequency range within the set period is called, and it is determined whether the current offset exceeds the adjustable frequency range. If not, the current frequency command is maintained unchanged. If it exceeds, the excess ratio is calculated to obtain the offset excess ratio;

[0018] S202: Based on the offset excess ratio, the current frequency change rate is calculated, and a set ratio threshold is called to determine whether the frequency change rate exceeds the threshold. If not, the current frequency instruction is kept unchanged. If it exceeds, a correction amplitude is calculated to obtain the frequency correction amplitude.

[0019] S203: calling the frequency correction amplitude, adjusting the current inverter output frequency instruction, calculating the adjusted frequency value, and using the adjusted frequency value as the current inverter output frequency instruction to obtain the inverter frequency correction value.

[0020] As a further solution of the present invention, the specific steps of S3 are:

[0021] S301: Calling the frequency correction value of the inverter, obtaining the current motor speed and the output frequency increment of the inverter, calculating the rate of change of the motor speed, comparing the rate of change with the output frequency increment of the inverter, screening the time interval of speed lag, detecting the motor current change trend within the interval, extracting the continuous increase interval of the motor current, and obtaining the motor speed lag rate;

[0022] S302: Analyzing inertia disturbance characteristics based on the motor speed hysteresis rate to determine whether the motor speed hysteresis meets the inertia disturbance condition, extracting the time period that meets the condition, calculating the motor power fluctuation value within the inertia disturbance period, and establishing an inertia disturbance range based on the maximum frequency variation of the inverter to obtain the inertia disturbance amplitude;

[0023] S303: Call the inertia disturbance amplitude, set the inverter power upper limit, and combine it with the maximum frequency change amplitude of the inverter to calculate the power adjustment value within the inertia disturbance range, limit the frequency adjustment amplitude of the inverter, and generate the inertia compensation power limit value.

[0024] As a further solution of the present invention, the specific calculation formula for calculating the power adjustment value within the inertia disturbance range is:

[0025]

[0026] Among them, ΔW represents the power adjustment value within the inertia disturbance range, M represents the inertia value corresponding to the disturbance, Δf represents the frequency change amplitude of the disturbance, k represents the acceleration of the frequency change during the disturbance, d represents the duration of the disturbance, Q1, Q2, and Q3 represent the dynamic response power values under the three disturbance scenarios, ε represents the standard deviation of the inertia value in the three disturbances, and M m Represents the average value of the inertia in three disturbances.

[0027] As a further solution of the present invention, the specific steps of S4 are:

[0028] S401: Obtain the inertia compensation power limit value, detect the current value of the DC bus voltage, compare it with the bus voltage value at the previous moment, calculate the voltage change amplitude, and determine whether it exceeds the set ratio. If it exceeds the set ratio, continue to detect the recovery of the bus voltage, calculate the hysteresis degree, and generate the voltage drop and recovery hysteresis amount;

[0029] S402: Calculate the current frequency of the inverter based on the voltage drop and recovery hysteresis, compare it with the set average frequency, obtain a change between the two, and determine whether the change is a positive number. If the change is positive, determine that reverse compression is required to generate the inverter frequency change;

[0030] S403: calling the frequency change of the inverter, performing inverse compression calculation, adjusting the frequency adjustment value of the bus voltage compensation, screening the compensated voltage change that meets the set standard, and generating the bus voltage compensation frequency adjustment value.

[0031] As a further embodiment of the present invention, the method further comprises:

[0032] S5: calling the bus voltage compensation frequency adjustment value, combining the hydraulic trend level and the inertia disturbance state, giving priority to power limitation, and dynamically adjusting the frequency adjustment rate of the frequency converter according to the flow acceleration and pressure gradient to generate the frequency conversion adjustment priority;

[0033] The frequency conversion adjustment priority includes power priority, frequency adjustment priority, hydraulic trend priority

[0034] The specific steps of S5 are:

[0035] S501: calling the bus voltage compensation frequency adjustment value, obtaining the current hydraulic trend level, detecting the inertia disturbance state, calculating the deviation between the bus voltage compensation frequency adjustment value and the hydraulic trend level, performing preliminary screening of power limits based on the deviation and the inertia disturbance state, calculating the power limit threshold during the screening process, and comparing the bus voltage compensation frequency adjustment value with the power limit threshold to determine an initial power limit range and generate an initial power limit interval;

[0036] S502: Based on the initial power limit interval, the current flow acceleration and pressure gradient are obtained, the impact of the flow acceleration on the power limit is calculated, and the impact of the pressure gradient on the power output change is detected. Based on the two, an adjusted power limit range is calculated. The dynamic change trend of the frequency regulation rate of the inverter is determined by combining the bus voltage compensation frequency adjustment value and the adjusted power limit range to generate a frequency regulation dynamic change rate.

[0037] S503: Call the frequency regulation dynamic change rate, calculate the frequency change rate of the inverter at the difference time point, obtain the time distribution of the rate change, and detect the fluctuation amplitude in the difference time period, adjust the frequency regulation priority of the inverter according to the fluctuation amplitude, and generate the frequency regulation priority in combination with the current power limit range and the inverter operating status.

[0038] As a further solution of the present invention, the specific calculation formula for calculating the impact of flow acceleration on power limitation is:

[0039]

[0040] Where ΔP a,i represents the magnitude of the impact of flow acceleration on power limitation in the i-th control cycle, a f,j Represents the flow acceleration value collected by the jth measuring point in the current cycle, U j Represents the voltage difference between the input and output of the jth measuring point, namely U j =V in,j -V out,j , Z j Represents the equivalent impedance correction value of the jth measuring point, namely Z j =R j +β j , γ i represents the weight adjustment coefficient of the i-th control period, Represents the average flow acceleration of all measuring points in the i-th control cycle, and n represents the total number of measuring points.

[0041] An automated water pump control strategy and energy efficiency optimization system, comprising:

[0042] The hydraulic trend determination module collects instantaneous flow data from the pump outlet pipe section, calculates the flow difference between adjacent sampling points and divides it by the time interval to generate the flow acceleration. It also simultaneously extracts the pressure difference between adjacent nodes to determine the pressure gradient direction. Through the vector cross product operation of the flow acceleration and the pressure gradient direction, it determines the hydraulic imbalance state and generates the hydraulic trend determination result.

[0043] The frequency dynamic adjustment module calculates the absolute difference between the inverter output frequency and the reference stable frequency based on the hydraulic trend determination result to obtain the frequency offset amplitude. Combined with the maximum adjustable frequency range within the inverter rated range setting period, when the frequency change rate exceeds the range ratio, the inverter frequency correction value is generated according to the offset amplitude.

[0044] The inertia disturbance compensation module calls the inverter frequency correction value, calculates the motor speed change rate and compares it with the frequency increment. If the difference continues to increase and the motor current exceeds the steady-state threshold, the inverter power upper limit is set according to the rated power, the frequency correction amplitude threshold is limited, and the inertia compensation power limit value is generated;

[0045] The bus voltage regulation module calls the inertia compensation power limit value and calculates the absolute value of the difference between the DC bus voltage and the reference voltage in real time. When the difference exceeds a set ratio and does not recover within a duration, the module extracts the deviation between the inverter frequency and the average frequency. Under positive deviation, the correction amplitude is reversely compressed according to the difference ratio to generate a bus voltage compensation frequency adjustment value.

[0046] The frequency conversion regulation optimization module integrates the bus voltage compensation frequency adjustment value, the hydraulic trend determination result, and the inertia compensation power limit value, and uses the power limit value as the priority judgment basis. If the critical condition of the inverter power upper limit setting is reached, the regulation action is frozen. Otherwise, the amplitude change of the frequency correction is adjusted according to the matching degree of the angle between the flow acceleration and the pressure gradient direction to generate the frequency conversion regulation priority.

[0047] Compared with the prior art, the advantages and positive effects of the present invention are:

[0048] In the present invention, the ability to perceive dynamic changes in the fluid is improved by matching flow acceleration with pressure gradient, and the frequency adjustment of the inverter is optimized in combination with frequency offset calculation to reduce the increase in energy consumption caused by hysteresis. Based on the correlation analysis between the motor speed change rate and current fluctuation, accurate identification of inertia disturbance is achieved. The bus voltage dynamic monitoring and reverse compression strategy are combined to improve the timeliness of voltage compensation. The inverter frequency is dynamically adjusted in combination with multiple parameters to improve response speed and energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the steps of the present invention

[0050] Figure 2It is a system module diagram of the present invention. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0052] In the description of the present invention, it should be understood that the terms "length," "width," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," and the like, indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, in the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

[0053] See also Figure 1 , an automated water pump control strategy and energy efficiency optimization method, comprising the following steps:

[0054] S1: Obtain the instantaneous flow data of the pump outlet pipe section, calculate the flow acceleration, determine the pressure gradient direction of the adjacent pipe section nodes, and generate the hydraulic trend determination result by cross-matching the flow acceleration and the pressure gradient direction;

[0055] S2: Based on the hydraulic trend determination result, calculate the deviation between the current inverter output frequency command and the reference stable frequency, set the maximum adjustable frequency range within the cycle, and trigger frequency adjustment if the frequency change rate exceeds the set ratio to generate the inverter frequency correction value;

[0056] S3: Call the inverter frequency correction value, calculate the motor speed change rate, and compare it with the inverter output frequency increment. If the speed lags and the motor current continues to rise, it is marked as inertia disturbance, and the inverter power upper limit and the inverter maximum frequency change range are set to generate the inertia compensation power limit value;

[0057] S4: Based on the inertia compensation power limit value, the change amplitude of the DC bus voltage is calculated. If the bus voltage drops by more than the set ratio and recovers with lag, the change between the current inverter frequency and the set average frequency is calculated. If the change is positive, reverse compression is performed to generate the bus voltage compensation frequency adjustment value.

[0058] S5: Call the bus voltage compensation frequency adjustment value, combine the hydraulic trend level and inertia disturbance status, prioritize power limitation, and dynamically adjust the frequency regulation rate of the frequency converter according to the flow acceleration and pressure gradient to generate the frequency conversion regulation priority.

[0059] The hydraulic trend determination results include flow change trend, pressure gradient direction, and hydraulic stability. The inverter frequency correction value includes frequency increment, frequency decrement, and frequency stability adjustment. The inertia compensation power limit value includes maximum power limit, frequency change constraint, and current upper limit setting. The bus voltage compensation frequency adjustment value includes voltage compensation increment, frequency adjustment amplitude, and reverse compression ratio. The frequency conversion adjustment priority includes power priority, frequency adjustment priority, and hydraulic trend priority.

[0060] The specific steps of S1 are:

[0061] S101: Obtain instantaneous flow data of the water pump outlet pipe section, call the instantaneous flow values at adjacent moments, calculate the flow rate change rate within adjacent time intervals, calculate the flow acceleration based on the ratio of the flow rate change rate to the time interval, extract the change trend in the time series based on the calculated flow acceleration, and obtain the flow acceleration value;

[0062] First, install a flow sensor, such as an electromagnetic flowmeter or ultrasonic flowmeter, at the outlet pipe section of the water pump, and record the instantaneous flow value and timestamp at a sampling frequency of 1 Hz. The recorded data is stored in a time series and used for subsequent calculations. After recording the flow data, compare the instantaneous flow values at adjacent time points and calculate the flow rate change rate within adjacent time intervals. For example, if the flow rate is 10 L / s at a certain moment and 12 L / s at the next moment, the flow rate change rate is 2 L / s per second. Continue to calculate the flow acceleration based on the flow rate change rate, that is, the change amplitude of the flow rate change rate per unit time. For example, the flow rate change rate at the previous moment was 1.5 L / s 2 , the rate of change at this moment is 2L / s 2 , the flow rate acceleration increases by 0.5L / s per second 3 ,Then, the calculated flow acceleration is subjected to time series trend analysis, and the sliding average or difference method is used to smooth the data or extract the trend. For example, the average acceleration of the last three measurements is calculated. If the flow accelerations at the first three moments are 2, 3, and 4 L / s respectively, 3 , the average value is 3L / s 3 , which can reflect the overall change of flow acceleration and finally obtain the flow acceleration value.

[0063] S102: Based on the flow acceleration value, pressure data of adjacent pipe segment nodes are obtained, the pressure values of the adjacent nodes are called, and the pressure difference between the adjacent nodes is calculated. Based on the length of the pipe segment, the pressure gradient per unit length is calculated. Based on the calculated pressure gradient, the directionality of the pressure gradient is determined to obtain pressure gradient direction data;

[0064] First, install pressure sensors, such as pressure transmitters, at key nodes in the pipeline and record pressure data at the same time interval as the flow measurement. Assuming that the pressures at two adjacent measuring points are 200kPa and 180kPa respectively, the pressure difference is 20kPa. Then, calculate the pressure gradient per unit length based on the length of the pipe section. For example, if the pipeline length is 100m, the pressure gradient decreases by 0.2kPa per meter. Next, determine the directionality of the pressure gradient. If the upstream pressure is higher than the downstream pressure, the fluid flows in the direction of the pressure gradient; otherwise, the direction is opposite. Finally, obtain the pressure gradient direction data.

[0065] S103: Calling the flow acceleration value and the pressure gradient direction data, cross-matching the directionality of the two, determining whether the direction of the flow acceleration is consistent with the pressure gradient direction, and classifying the hydraulic state trend based on the matching result to obtain a hydraulic trend determination result;

[0066] Assuming that the flow acceleration is positive and the pressure gradient is negative at a certain moment, it means that the flow increases but the pressure decreases, and the directions are opposite. If the flow acceleration is negative and the pressure gradient is positive, the flow decreases but the pressure increases, and the directions are also opposite. If both are positive or negative, the directions are consistent. By traversing the time series data, calculating the matching situation, and setting classification standards, for example, if the direction of the flow acceleration is opposite to the direction of the pressure gradient accounts for more than 60%, it is judged that the trend is unstable. If the directions are consistent for more than 80%, it is judged that the trend is stable. Finally, the hydraulic trend judgment result is obtained.

[0067] The specific steps of S2 are:

[0068] S201: Based on the hydraulic trend determination result, the current inverter output frequency command and the reference stable frequency are obtained, the offset between the two is calculated, the maximum adjustable frequency range within the set period is called, and it is determined whether the current offset exceeds the adjustable frequency range. If not, the current frequency command is maintained unchanged. If it exceeds, the excess ratio is calculated to obtain the offset excess ratio;

[0069] First, real-time monitoring is required to collect hydraulic parameters such as the pump station's inlet flow rate, head, and pipe network pressure. The system then compares the direction and magnitude of change in the current values with historical hydraulic data from a set period. For example, if the pressure and flow rate have both decreased over the past 10 minutes, the trend can be preliminarily determined to be attenuating. Further, expert rules or models can be used to determine the type of hydraulic trend. Once the trend has been determined, the system retrieves the current inverter's output frequency command and reads the set stable operating frequency as a reference. The difference between the two is then compared to determine the frequency offset. For example, if the current frequency is 48 Hz and the reference frequency is 50 Hz, the offset is 2 Hz. The system then retrieves the maximum adjustable frequency range specified in the settings file, e.g., 3 Hz, to determine if the offset is within this range. If 2 Hz is within this range, the frequency remains unchanged. If the offset exceeds this range, for example, if the offset is 4 Hz and the maximum range is only 3 Hz, the percentage of excess offset is calculated. This percentage is determined by comparing the current offset value with the maximum allowable value and is used to subsequently modify frequency control, ultimately determining the excess offset ratio.

[0070] S202: Based on the offset excess ratio, the current frequency change rate is calculated, and the set ratio threshold is called to determine whether the frequency change rate exceeds the threshold. If not, the current frequency instruction is kept unchanged. If it exceeds, the correction amplitude is calculated to obtain the frequency correction amplitude.

[0071] The obtained offset exceeds the ratio, and the set frequency adjustment time period is called. The frequency change rate is calculated by numerically processing the period and the offset ratio. For example, in a scenario where the frequency offset is 4 Hz and the adjustment period is 5 seconds, the frequency change rate can be obtained by a simple ratio of the change value to the time, that is, the frequency amount to be adjusted per unit time. Then the set frequency change rate threshold is called. This threshold is preset when designing the control strategy, for example, it is set to 0.6 Hz per second. The frequency change rate is judged by comparing the size relationship between the frequency change rate and the set threshold. If the currently calculated frequency change rate is less than the threshold, no adjustment is required to the frequency command; if the frequency change rate is greater than the threshold, the required correction amplitude is calculated based on the difference between the excess part and the threshold. For example, when the change rate is 0.8 Hz per second and the threshold is 0.6 Hz per second, the frequency correction amplitude is the difference between the two, and the frequency correction amplitude is finally obtained.

[0072] S203: Calling the frequency correction amplitude, adjusting the current inverter output frequency command, calculating the adjusted frequency value, and using the adjusted frequency value as the current inverter output frequency command to obtain the inverter frequency correction value;

[0073] After calling the frequency correction amplitude obtained above, the frequency instruction of the current inverter is corrected. The correction direction can be determined by the relationship between the current frequency and the reference frequency. If the current frequency is lower than the reference value, the frequency should be increased, otherwise the frequency should be reduced. In actual operation, the frequency increase or decrease value required for this round of adjustment is calculated according to the set adjustment cycle and correction amplitude, and the increase or decrease value is superimposed on the current frequency value to obtain a new frequency instruction value. For example, if the current frequency is 48Hz, the correction amplitude is set to 0.2Hz per second, and the adjustment cycle is 5 seconds, the frequency is adjusted to 49Hz in the current cycle, and then 49Hz is set as the new frequency output instruction of the inverter. This process can be repeated in the next cycle until the frequency returns to the reference frequency range, and finally the inverter frequency correction value is obtained.

[0074] The specific steps of S3 are:

[0075] S301: Call the frequency correction value of the inverter to obtain the current motor speed and the inverter output frequency increment, calculate the rate of change of the motor speed, compare the rate of change with the inverter output frequency increment, select the time interval of speed lag, detect the motor current change trend within the interval, extract the continuous increase interval of the motor current, and obtain the motor speed lag rate;

[0076] After calling the frequency correction value of the inverter, you first need to obtain the inverter output frequency and its change increment in real time. For example, in an industrial conveyor belt, the inverter frequency increases from 45 Hz to 50 Hz in a certain cycle, that is, the frequency increment is 5 Hz. At the same time, call the data of the motor speed sensor to record the change of the motor speed during this period. For example, the speed increases from 1350 rpm to 1370 rpm, and the speed change is 20 rpm. Then, based on the length of the time period, assuming it is 2 seconds, the actual speed change rate of the motor is calculated to be 10 rpm per second. At the same time, according to the rated parameters, 50 Hz corresponds to 1500 rpm. It can be seen that each Hz is approximately equal to a change of 30 rpm. If the inverter increases by 5 Hz, the expected motor speed should increase by 150 rpm, and the speed should increase by 100 rpm per second. The actual speed is 75 rpm, and then the actual speed is compared with the expected speed, and the hysteresis rate of the speed response is 13.3%. If the hysteresis rate threshold is set to 20%, the current situation does not belong to the hysteresis period. However, if the motor speed in other intervals only increases by 10 rpm and the frequency changes by 5 Hz, the hysteresis rate is 93.3%. In this case, the interval is identified as the hysteresis period. Next, the motor current data analysis link of this interval is entered, and the current detection module is called to obtain the motor current change sequence within this period. For example, if the data is 10 A, 12 A, 15 A, and 18 A, it is identified that it shows a monotonically increasing trend and three consecutive points meet the increasing conditions. It is judged to be a continuous increasing trend. The time period is recorded as a window with outstanding hysteresis performance. Finally, the motor speed hysteresis rate is extracted through this processing flow.

[0077] S302: Based on the motor speed hysteresis, analyze the inertia disturbance characteristics to determine whether the motor speed hysteresis meets the inertia disturbance condition. Then, extract the time period that meets the condition and calculate the motor power fluctuation value within the inertia disturbance period. Combined with the maximum frequency variation of the inverter, establish the inertia disturbance range and obtain the inertia disturbance amplitude.

[0078] Based on the extracted motor speed hysteresis rate, subsequent analysis is performed. Assuming that the hysteresis rate is 85% in a certain operating cycle, which is significantly higher than the set threshold of 50%, it is determined to be a high hysteresis behavior. Next, analyze whether the time period is in an inertia disturbance state and detect whether the current change rate exceeds the set standard. For example, if the current rises from 10A to 20A, the change amplitude is 10A, and the duration is more than 2 seconds, the disturbance judgment condition is met. Mark the period as an inertia disturbance period and extract the motor power change in this period from the historical power curve. For example, if the power rises from 4A to 20A, the change amplitude is 10A and the duration is more than 2 seconds, the disturbance judgment condition is met. The kilowatts increase to 7.5 kilowatts, and the fluctuation value is 3.5 kilowatts. Combined with the rated frequency change capability of the inverter, for example, the allowable frequency adjustment range is 40 to 50 Hz, and the maximum is 10 Hz, a response range between power and frequency is established. If empirical data or calibration data show that each Hz frequency change can bring about a power fluctuation of 0.7 kilowatts, then the current disturbance performance can be summarized as corresponding to the 5 Hz variation range. On this basis, the inertia disturbance amplitude is extracted based on the maximum fluctuation value within the actual disturbance time, which is used as an important parameter for subsequent dynamic response adjustment.

[0079] S303: Call the inertia disturbance amplitude to set the inverter power upper limit. Combined with the maximum frequency change amplitude of the inverter, the power adjustment value within the inertia disturbance range is calculated to limit the frequency adjustment amplitude of the inverter and generate the inertia compensation power limit value.

[0080] The specific calculation formula for calculating the power adjustment value within the inertia disturbance range is:

[0081]

[0082] Among them, ΔW represents the power adjustment value within the inertia disturbance range, M represents the inertia value corresponding to the disturbance, Δf represents the frequency change amplitude of the disturbance, k represents the acceleration of the frequency change during the disturbance, d represents the duration of the disturbance, Q1, Q2, and Q3 represent the dynamic response power values under the three disturbance scenarios, ε represents the standard deviation of the inertia value in the three disturbances, and M m Represents the average value of inertia in three disturbances;

[0083] Detailed explanation of the formula and calculation process:

[0084] ΔW calculates the power change under specific disturbance conditions by monitoring the actual operating data of the system.

[0085] M is calculated through physical models, combining the mass distribution and geometry of the system to obtain a specific value.

[0086] Δf is monitored and recorded in real time through a frequency meter or data acquisition system.

[0087] k is calculated as the ratio of the frequency change amplitude Δf to the square root of the disturbance duration d, that is, k = Δf / √d.

[0088] d. Accurately record the start and end times of the disturbance using an event recorder or time synchronization system, and calculate the duration.

[0089] Q1, Q2, and Q3 are measured experimentally or analyzed by simulation, and the power response values of the systems are recorded respectively under the same disturbance conditions.

[0090] ε calculates the standard deviation of the inertia value under multiple disturbances, reflecting the stability of the system inertia.

[0091] M m Calculate the average value of the inertia under multiple disturbances as the representative value of the system inertia.

[0092] Formula calculation derivation process:

[0093] Calculate the frequency change acceleration k:

[0094] formula:

[0095] Calculation process: Assume that in a disturbance, the frequency change amplitude Δf is 2Hz and the duration d is 0.5s, then

[0096] Calculate the average dynamic response power:

[0097] formula:

[0098] Calculation process: Assuming that the power response values under three disturbances are Q1 = 100W, Q2 = 110W, and Q3 = 105W, the average value is

[0099] Calculate the standard deviation of inertia ε:

[0100] formula:

[0101] Assume that the inertia values under the five disturbances are M1 = 1.2 kg·m 2 , M2=1.3kg·m 2 , M3=1.1kg·m 2 , M4=1.2kg·m 2 , M5=1.3kg·m 2, average value M m =1.22kg·m 2 ,but

[0102] Calculate the average inertia M m :

[0103] formula:

[0104] Calculation process: Same as above,

[0105] Calculate the power adjustment value ΔW:

[0106] formula:

[0107]

[0108] Calculation process:

[0109] Assume that in a disturbance, M = 1.2 kg·m 2 , Δf=2Hz, d=0.5s, k≈2.828Hz / s^0.5, Q1=100W, Q2=110W, Q3=105W, ε≈0.081kg·m 2 , M m =1.22kg·m 2 .

[0110] First, calculate the part within the brackets:

[0111]

[0112] Then, calculate the denominator in the formula:

[0113]

[0114] Finally, calculate ΔW:

[0115]

[0116] Result description:

[0117] The calculation results show that the power adjustment value after considering the inertia disturbance is 89.88 W. This means that during the disturbance, the inverter needs to adjust the power by 89.88 W to ensure system stability and frequency control.

[0118] The specific steps of S4 are:

[0119] S401: Obtain the inertia compensation power limit value, detect the current value of the DC bus voltage, compare it with the bus voltage value at the previous moment, calculate the voltage change amplitude, and determine whether it exceeds the set ratio. If it exceeds the set ratio, continue to detect the recovery of the bus voltage, calculate the hysteresis degree, and generate the voltage drop and recovery hysteresis;

[0120] After obtaining the inertia compensation power limit, the current DC bus voltage is monitored. This process involves using a voltage sensor to read voltage data in real time. The current voltage value is then compared with the previous bus voltage value and the voltage change is calculated. If the change exceeds a set proportional threshold, it indicates possible voltage fluctuation or instability. The set proportional is determined by safe operating parameters, for example, 5% of the voltage. Detecting a voltage change exceeding the threshold automatically triggers further diagnostics. This includes detecting the bus voltage recovery, monitoring the speed and stability of voltage recovery, and calculating the degree of hysteresis. Through this series of actions, the impact of voltage fluctuations on overall equipment operation is assessed, and a quantitative report is generated containing voltage sag and recovery hysteresis. This report is crucial for adjusting operating parameters. This operation observes the bus voltage changes over a specific period and compares them with the set threshold to determine whether there are any anomalies, thereby generating voltage sag and recovery hysteresis. This process is critical for maintaining stable operation.

[0121] S402: Based on the voltage drop and recovery hysteresis, the current inverter frequency is calculated and compared with the set average frequency to obtain the difference between the two. It is determined whether the difference is a positive number. If the difference is positive, it is determined that reverse compression is required to generate the inverter frequency change.

[0122] First, the current inverter frequency is calculated and compared with the set average frequency. This process is mainly completed by internal control software, which includes obtaining real-time frequency data of the inverter, which is obtained through a frequency sensor or directly from the feedback signal of the inverter control unit. At the same time, the set average frequency is a standard value calculated based on the optimal operating conditions. By comparing these two frequencies, it is possible to determine whether the current operating status is normal. If the calculation result shows that the current frequency is higher than the average frequency, that is, the change is positive, it is determined that reverse compression is required to adjust the frequency. This decision is based on the dynamic relationship between voltage and frequency and the need for stable operation. For example, in grid frequency regulation, reverse compression is one of the commonly used technologies used to balance grid load and power generation. In this way, not only the voltage and frequency are kept stable, but also the distribution and utilization of energy can be effectively managed to generate inverter frequency changes.

[0123] S403: Call the frequency change of the inverter, perform inverse compression calculation, adjust the frequency adjustment value of the bus voltage compensation, screen the compensated voltage changes that meet the set standards, and generate the bus voltage compensation frequency adjustment value;

[0124] After the frequency change of the inverter is called, the inverse compression calculation will be performed, which involves a series of adjustment and optimization steps. The first is to adapt to the actual voltage demand by adjusting the output frequency of the inverter. This is set in the control unit of the inverter. According to the frequency change, the frequency is automatically adjusted to match the actual change in voltage. Next is the screening process, which will check whether the adjusted bus voltage meets the set operating standards. During this process, the voltage response after each frequency adjustment will be recorded to determine which adjustment values can restore the bus voltage to the set normal range. This set standard is pre-set according to the safety and efficiency requirements of the equipment. For example, the bus voltage needs to be kept within a specific voltage range to ensure the safe operation and energy efficiency of the equipment, and finally a bus voltage compensation frequency adjustment value is generated.

[0125] The specific steps of S5 are:

[0126] S501: Call the bus voltage compensation frequency adjustment value, obtain the current hydraulic trend level, detect the inertia disturbance state, calculate the deviation between the bus voltage compensation frequency adjustment value and the hydraulic trend level, perform preliminary power limit screening based on the deviation and the inertia disturbance state, calculate the power limit threshold during the screening process, and compare the bus voltage compensation frequency adjustment value with the power limit threshold to determine the initial power limit range and generate the initial power limit interval;

[0127] After calling the bus voltage compensation frequency adjustment value, the current hydraulic trend level is first obtained from the field sensor module. This level can be calculated by weighting factors such as the water level change rate, turbine flow adjustment speed and total potential energy of the incoming water. For example, the water level change trend is monitored in minutes and divided into five levels. Level one means that the flow is stable and unchanged, and level five means that the incoming water surges by more than 20% of the established flow in a short period of time. Then the current inertia disturbance state is read. This state is judged by the equipment operation monitoring, including load surge, short-term voltage drop, rotational inertia change trend, etc. The corresponding logic bit is triggered by the sensor. When the disturbance state is activated, it participates in the subsequent control logic judgment. Next, the voltage compensation frequency adjustment value is compared with the frequency level corresponding to the current hydraulic trend level to calculate the deviation between the two. For example, the compensation frequency is 47 Hz, and the current hydraulic trend corresponds to an ideal frequency of 45 Hz. The deviation is 2 Hz. The power limitation scheme is preliminarily screened based on the deviation and the disturbance state. The screening strategy can be set to use the high limit gear if the deviation is greater than two Hz and the disturbance is activated, otherwise the medium and low gears are used. The power limit threshold needs to be calculated during the screening. The threshold can be calculated by weighting the bus voltage, motor characteristics, and hydraulic level. For example, if the bus voltage is 800 volts, the corresponding rated limit power is 200 kilowatts, which is adjusted to 180 kilowatts under the disturbance state. The power mapping value corresponding to the current frequency adjustment value is then compared with the above threshold. For example, the current frequency of 47 Hz corresponds to a power output of 190 kilowatts, which exceeds the threshold. It is preliminarily judged that power should be limited. The result will be used to determine the initial range of power limit and provide an initial power limit interval as output, for example, defined as a range of 160 to 180 kilowatts. This range will continue to be dynamically adjusted in the next step.

[0128] S502: Based on the initial power limit range, the current flow acceleration and pressure gradient are obtained, the impact of the flow acceleration on the power limit is calculated, and the impact of the pressure gradient on the power output change is detected. Based on the two, an adjusted power limit range is calculated. The dynamic change trend of the frequency regulation rate of the inverter is determined by combining the bus voltage compensation frequency adjustment value with the adjusted power limit range to generate a dynamic change rate of the frequency regulation.

[0129] The specific calculation formula for calculating the impact of flow acceleration on power limitation is:

[0130]

[0131] Where ΔP a,i represents the magnitude of the impact of flow acceleration on power limitation in the i-th control cycle, a f,j Represents the flow acceleration value collected by the jth measuring point in the current cycle, U j Represents the voltage difference between the input and output of the jth measuring point, namely U j =Vin,j -V out,j , Z j Represents the equivalent impedance correction value of the jth measuring point, namely Z j =R j +β j , γ i represents the weight adjustment coefficient of the i-th control period, represents the average flow acceleration of all measuring points in the i-th control cycle, and n represents the total number of measuring points;

[0132] Detailed explanation of the formula and the process of formula calculation and derivation:

[0133] a f,j The velocity change is collected in real time by a high-frequency thermal anemometer in the pipeline and the difference is calculated;

[0134] U j The voltage sensor collects V in,j and V out,j Then make the difference calculation;

[0135] Z j The measured pipeline equivalent resistance R j and the cycle pressure difference ratio coefficient β j Add together to get;

[0136] γ i Through system sensitivity experiment setting, the weight is increased when the error fluctuates violently, and is currently set to 0.85;

[0137] It is obtained by averaging all flow acceleration values collected in the current cycle.

[0138] Set the total number of measurement points to 3:

[0139] Measuring point 1: flow acceleration is 0.5m / s 2 , the inlet voltage is 220V, the outlet voltage is 210V, the equivalent resistance is 5Ω, and the cycle pressure difference ratio coefficient is 0.1;

[0140] Measuring point 2: flow acceleration is 0.7m / s 2 , the inlet voltage is 230V, the outlet voltage is 215V, the equivalent resistance is 6Ω, and the cycle pressure difference ratio coefficient is 0.15;

[0141] Measuring point 3: flow acceleration is 0.6m / s 2 , the inlet voltage is 225V, the outlet voltage is 220V, the equivalent resistance is 5.5Ω, and the cycle pressure difference ratio coefficient is 0.12.

[0142] Based on the above data, the calculation steps are as follows:

[0143] Calculate the voltage difference at each measuring point:

[0144] U1=220-210=10V,

[0145] U2=230-215=15V,

[0146] U3=225-220=5V.

[0147] Calculate the equivalent impedance correction for each measuring point:

[0148] Z1=5+0.1=5.1Ω,

[0149] Z2=6+0.15=6.15Ω,

[0150] Z3=5.5+0.12=5.62Ω.

[0151] Calculate the average acceleration during the cycle:

[0152]

[0153] Calculate the itemized scores for the weighted average section:

[0154] Measuring point 1 is

[0155]

[0156] Measuring point 2 is

[0157]

[0158] The three measuring points are

[0159]

[0160] Sum the three items and divide by the number of measurement points:

[0161]

[0162] Calculate the weighted terms:

[0163]

[0164] Finally, enter the formula for calculation:

[0165] ΔP a,i =|0.3296-0.51|=|-0.1804|=0.1804;

[0166] The results show that the impact of flow acceleration on the current power limit in the i-th control cycle is 0.1804. This value serves as an important basis for adjusting the power limit interval in subsequent steps. It is also used as one of the input factors for determining the frequency regulation trend. The higher the value, the stronger the coupling effect of the current cycle flow disturbance on the system output power, and the need to improve the response intensity of the dynamic adjustment of the power limit.

[0167] S503: Invoke the frequency regulation dynamic change rate to calculate the frequency change rate of the inverter at the difference time point, obtain the time distribution of the rate change, and detect the fluctuation amplitude in the difference time period. Adjust the frequency regulation priority of the inverter according to the fluctuation amplitude, and generate the frequency regulation priority based on the current power limit range and the inverter operating status;

[0168] After calling the frequency adjustment dynamic change rate, the change rate is input into the frequency prediction and control module to calculate and analyze the output frequency change rate of the inverter at multiple different time points. For example, the difference time point interval is set to 10 seconds, and the frequency values at 10 seconds, 20 seconds, and 30 seconds are observed. If the frequency values at these time points are 46.5, 46.3, and 46.0 Hz respectively, the change rate in each interval is 0.02 Hz, 0.03 Hz, and 0.03 Hz per second. Based on these rate data, a time distribution diagram is compiled, and it is concluded that the frequency change is slow in the early stage and tends to accelerate in the later stage. Then, the fluctuation detection stage is entered to determine whether the frequency fluctuation amplitude in these time periods is Exceeding the set allowable range, for example, the set fluctuation allowable is ±0.2 Hz. If the frequency rises to 46.8 Hz for a short time in a certain period of time and then falls back, the fluctuation is 0.8 Hz, which exceeds the allowable value and is marked as an unstable segment. The frequency regulation priority of the inverter is adjusted accordingly. The priority is divided into three levels: high, medium and low. For example, a medium priority is given in a stable segment and a high priority is set in an unstable segment, so that the response in future control is faster. Combined with the current power limit range and the current operating status of the inverter, for example, if it is currently running in a half-load state and the output power is 175 kWh, the frequency change priority will be corrected to a medium-high level, and finally the frequency regulation priority for the next cycle control logic call is generated.

[0169] See also Figure 2 , an automated water pump control strategy and energy efficiency optimization system, including:

[0170] The hydraulic trend determination module collects instantaneous flow data from the pump outlet pipe section, calculates the flow difference between adjacent sampling points and divides it by the time interval to generate the flow acceleration. It also simultaneously extracts the pressure difference between adjacent nodes to determine the pressure gradient direction. Through the vector cross product operation of the flow acceleration and the pressure gradient direction, it determines the hydraulic imbalance state and generates the hydraulic trend determination result.

[0171] The frequency dynamic adjustment module calculates the absolute difference between the inverter output frequency and the reference stable frequency based on the hydraulic trend determination result to obtain the frequency offset amplitude. Combined with the inverter's rated range to set the maximum adjustable frequency range within the cycle, when the frequency change rate exceeds the range ratio, the inverter frequency correction value is generated according to the offset amplitude.

[0172] The inertia disturbance compensation module calls the inverter frequency correction value, calculates the motor speed change rate, and compares it with the frequency increment. If the difference continues to increase and the motor current exceeds the steady-state threshold, the inverter power upper limit is set according to the rated power, the frequency correction amplitude threshold is limited, and the inertia compensation power limit value is generated;

[0173] The bus voltage regulation module uses the inertia compensation power limit value to calculate the absolute value of the difference between the DC bus voltage and the reference voltage in real time. When the difference exceeds the set ratio and does not recover within the duration, it extracts the deviation between the inverter frequency and the average frequency. Under positive deviation, the correction amplitude is reversely compressed according to the difference ratio to generate the bus voltage compensation frequency adjustment value.

[0174] The frequency conversion regulation optimization module integrates the bus voltage compensation frequency adjustment value, hydraulic trend judgment result and inertia compensation power limit value, and uses the power limit value as the priority judgment basis. If the critical condition of the inverter power upper limit setting is reached, the regulation action is frozen. Otherwise, the amplitude change of the frequency correction is adjusted according to the matching degree of the angle between the flow acceleration and the pressure gradient direction to generate the frequency conversion regulation priority.

[0175] The above are merely preferred embodiments of the present invention and do not limit the present invention in any other form. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An automated water pump control strategy and energy efficiency optimization method, characterized in that: The following steps are involved: S1: Obtain the instantaneous flow data of the pump outlet pipe section, calculate the flow acceleration, determine the pressure gradient direction of the adjacent pipe section nodes, and generate the hydraulic trend determination result by cross-matching the flow acceleration and the pressure gradient direction; S2: Based on the hydraulic trend determination result, the deviation between the current inverter output frequency command and the reference stable frequency is calculated, and the maximum adjustable frequency range within the period is set. If the frequency change rate exceeds the set ratio, the frequency adjustment is triggered to generate the inverter frequency correction value; S3: Calling the inverter frequency correction value, calculating the motor speed change rate, and comparing it with the inverter output frequency increment. If the speed lags and the motor current continues to rise, it is marked as inertia disturbance, and the inverter power upper limit and the inverter maximum frequency change range are set to generate the inertia compensation power limit value; S4: Based on the inertia compensation power limit value, the change amplitude of the DC bus voltage is calculated. If the bus voltage drops by more than the set ratio and recovers with lag, the change between the current inverter frequency and the set average frequency is calculated. If the change is positive, reverse compression is performed to generate the bus voltage compensation frequency adjustment value.

2. The automatic water pump control strategy and energy efficiency optimization method according to claim 1 is characterized in that: The hydraulic trend determination result includes flow change trend, pressure gradient direction, and hydraulic stability; the inverter frequency correction value includes frequency increment, frequency decrement, and frequency stability adjustment; the inertia compensation power limit value includes maximum power limit, frequency change constraint, and current upper limit setting; the bus voltage compensation frequency adjustment value includes voltage compensation increment, frequency adjustment amplitude, and reverse compression ratio.

3. The automatic water pump control strategy and energy efficiency optimization method according to claim 1 is characterized in that: The specific steps of S1 are: S101: Obtain instantaneous flow data of the water pump outlet pipe section, call the instantaneous flow values at adjacent moments, calculate the flow rate change rate within adjacent time intervals, calculate the flow acceleration based on the ratio of the flow rate change rate to the time interval, extract the change trend in the time series based on the calculated flow acceleration, and obtain the flow acceleration value; S102: Based on the flow acceleration value, pressure data of adjacent pipe segment nodes are obtained, the pressure values of the adjacent nodes are called, and the pressure difference between the adjacent nodes is calculated. Based on the length of the pipe segment, the pressure gradient per unit length is calculated. Based on the calculated pressure gradient, the directionality of the pressure gradient is determined to obtain pressure gradient direction data. S103: Call the flow acceleration value and the pressure gradient direction data, cross-match the directionality of the two, determine whether the direction of the flow acceleration is consistent with the pressure gradient direction, classify the trend of the hydraulic state based on the matching result, and obtain a hydraulic trend determination result.

4. The automatic water pump control strategy and energy efficiency optimization method according to claim 3 is characterized in that: The specific steps of S2 are: S201: Based on the hydraulic trend determination result, the current inverter output frequency command and the reference stable frequency are obtained, the offset between the two is calculated, the maximum adjustable frequency range within the set period is called, and it is determined whether the current offset exceeds the adjustable frequency range. If not, the current frequency command is maintained unchanged. If it exceeds, the excess ratio is calculated to obtain the offset excess ratio; S202: Based on the offset excess ratio, the current frequency change rate is calculated, and a set ratio threshold is called to determine whether the frequency change rate exceeds the threshold. If not, the current frequency instruction is kept unchanged. If it exceeds, a correction amplitude is calculated to obtain the frequency correction amplitude. S203: calling the frequency correction amplitude, adjusting the current inverter output frequency instruction, calculating the adjusted frequency value, and using the adjusted frequency value as the current inverter output frequency instruction to obtain the inverter frequency correction value.

5. The automatic water pump control strategy and energy efficiency optimization method according to claim 4 is characterized in that: The specific steps of S3 are: S301: Calling the frequency correction value of the inverter, obtaining the current motor speed and the output frequency increment of the inverter, calculating the rate of change of the motor speed, comparing the rate of change with the output frequency increment of the inverter, screening the time interval of speed lag, detecting the motor current change trend within the interval, extracting the continuous increase interval of the motor current, and obtaining the motor speed lag rate; S302: Analyzing inertia disturbance characteristics based on the motor speed hysteresis rate to determine whether the motor speed hysteresis meets the inertia disturbance condition, extracting the time period that meets the condition, calculating the motor power fluctuation value within the inertia disturbance period, and establishing an inertia disturbance range based on the maximum frequency variation of the inverter to obtain the inertia disturbance amplitude; S303: Call the inertia disturbance amplitude, set the inverter power upper limit, and combine it with the maximum frequency change amplitude of the inverter to calculate the power adjustment value within the inertia disturbance range, limit the frequency adjustment amplitude of the inverter, and generate the inertia compensation power limit value.

6. The automatic water pump control strategy and energy efficiency optimization method according to claim 5, characterized in that: The specific calculation formula for the power adjustment value within the inertia disturbance range is: Among them, ΔW represents the power adjustment value within the inertia disturbance range, M represents the inertia value corresponding to the disturbance, Δf represents the frequency change amplitude of the disturbance, k represents the acceleration of the frequency change during the disturbance, d represents the duration of the disturbance, Q1, Q2, and Q3 represent the dynamic response power values under the three disturbance scenarios, ε represents the standard deviation of the inertia value in the three disturbances, and M m Represents the average value of the inertia in three disturbances.

7. The automatic water pump control strategy and energy efficiency optimization method according to claim 5, characterized in that: The specific steps of S4 are: S401: Obtain the inertia compensation power limit value, detect the current value of the DC bus voltage, compare it with the bus voltage value at the previous moment, calculate the voltage change amplitude, and determine whether it exceeds the set ratio. If it exceeds the set ratio, continue to detect the recovery of the bus voltage, calculate the hysteresis degree, and generate the voltage drop and recovery hysteresis amount; S402: Calculate the current frequency of the inverter based on the voltage drop and recovery hysteresis, compare it with the set average frequency, obtain a change between the two, and determine whether the change is a positive number. If the change is positive, determine that reverse compression is required to generate the inverter frequency change; S403: calling the frequency change of the inverter, performing inverse compression calculation, adjusting the frequency adjustment value of the bus voltage compensation, screening the compensated voltage change that meets the set standard, and generating the bus voltage compensation frequency adjustment value.

8. The automatic water pump control strategy and energy efficiency optimization method according to claim 7, characterized in that: The method further comprises: S5: calling the bus voltage compensation frequency adjustment value, combining the hydraulic trend level and the inertia disturbance state, giving priority to power limitation, and dynamically adjusting the frequency adjustment rate of the frequency converter according to the flow acceleration and pressure gradient to generate the frequency conversion adjustment priority; The frequency conversion adjustment priority includes power priority, frequency adjustment priority, and hydraulic trend priority. The specific steps of S5 are: S501: calling the bus voltage compensation frequency adjustment value, obtaining the current hydraulic trend level, detecting the inertia disturbance state, calculating the deviation between the bus voltage compensation frequency adjustment value and the hydraulic trend level, performing preliminary screening of power limits based on the deviation and the inertia disturbance state, calculating the power limit threshold during the screening process, and comparing the bus voltage compensation frequency adjustment value with the power limit threshold to determine an initial power limit range and generate an initial power limit interval; S502: Based on the initial power limit interval, the current flow acceleration and pressure gradient are obtained, the impact of the flow acceleration on the power limit is calculated, and the impact of the pressure gradient on the power output change is detected. Based on the two, an adjusted power limit range is calculated. The dynamic change trend of the frequency regulation rate of the inverter is determined by combining the bus voltage compensation frequency adjustment value and the adjusted power limit range to generate a frequency regulation dynamic change rate. S503: Call the frequency regulation dynamic change rate, calculate the frequency change rate of the inverter at the difference time point, obtain the time distribution of the rate change, and detect the fluctuation amplitude in the difference time period, adjust the frequency regulation priority of the inverter according to the fluctuation amplitude, and generate the frequency regulation priority in combination with the current power limit range and the inverter operating status.

9. The automatic water pump control strategy and energy efficiency optimization method according to claim 8, characterized in that: The specific calculation formula for calculating the impact of flow acceleration on power limitation is: Where ΔP a,i represents the magnitude of the impact of flow acceleration on power limitation in the i-th control cycle, a f,j Represents the flow acceleration value collected by the jth measuring point in the current cycle, U j Represents the voltage difference between the input and output of the jth measuring point, namely U j =V in,j -V out,j , Z j Represents the equivalent impedance correction value of the jth measuring point, namely Z j =R j +β j , γ i represents the weight adjustment coefficient of the i-th control period, Represents the average flow acceleration of all measuring points in the i-th control cycle, and n represents the total number of measuring points.

10. An automated water pump control strategy and energy efficiency optimization system, characterized in that: According to an automated water pump control strategy and energy efficiency optimization method according to any one of claims 1 to 9, the system comprises: The hydraulic trend determination module collects instantaneous flow data from the pump outlet pipe section, calculates the flow difference between adjacent sampling points and divides it by the time interval to generate the flow acceleration. It also simultaneously extracts the pressure difference between adjacent nodes to determine the pressure gradient direction. Through the vector cross product operation of the flow acceleration and the pressure gradient direction, it determines the hydraulic imbalance state and generates the hydraulic trend determination result. The frequency dynamic adjustment module calculates the absolute difference between the inverter output frequency and the reference stable frequency based on the hydraulic trend determination result to obtain the frequency offset amplitude. Combined with the maximum adjustable frequency range within the inverter rated range setting period, when the frequency change rate exceeds the range ratio, the inverter frequency correction value is generated according to the offset amplitude. The inertia disturbance compensation module calls the inverter frequency correction value, calculates the motor speed change rate and compares it with the frequency increment. If the difference continues to increase and the motor current exceeds the steady-state threshold, the inverter power upper limit is set according to the rated power, the frequency correction amplitude threshold is limited, and the inertia compensation power limit value is generated; The bus voltage regulation module calls the inertia compensation power limit value and calculates the absolute value of the difference between the DC bus voltage and the reference voltage in real time. When the difference exceeds a set ratio and does not recover within a duration, the module extracts the deviation between the inverter frequency and the average frequency. Under positive deviation, the correction amplitude is reversely compressed according to the difference ratio to generate a bus voltage compensation frequency adjustment value. The frequency conversion regulation optimization module integrates the bus voltage compensation frequency adjustment value, the hydraulic trend determination result, and the inertia compensation power limit value, and uses the power limit value as the priority judgment basis. If the critical condition of the inverter power upper limit setting is reached, the regulation action is frozen. Otherwise, the amplitude change of the frequency correction is adjusted according to the matching degree of the angle between the flow acceleration and the pressure gradient direction to generate the frequency conversion regulation priority.

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