Sensorless flow and lift detection method and device for water pump system

Abstract

The invention belongs to the technical field of water pumps, and discloses a sensorless flow and lift detection method and device for a water pump system.The method comprises the steps that the flow value, the power value and the lift value of a water pump measured by changing the valve opening degree of the water pump at different rotating speeds are collected; fitting to obtain a power-flow equation and a lift-flow equation corresponding to each rotating speed; substituting the flow values into all the power-flow equations to obtain power values and corresponding rotating speeds, and fitting to obtain a power-rotating speed equation corresponding to each flow value; and obtaining a known rotating speed value and a power value of the water pump, substituting the rotating speed value and the power value into all the power-rotating speed equations, determining a flow value range, performing linear compensation in the flow value range to obtain a flow value, and substituting the flow value obtained by linear compensation calculation into the lift-flow equation at the corresponding rotating speed to obtain a lift value. According to the invention, flow and lift data are measured without a sensor, the performance test cost of the water pump system is reduced, and the measurement precision is high.

Description

Technical Field

[0001] The invention belongs to the technical field of water pumps, and in particular relates to a sensorless flow and head detection method and device for a water pump system. Background Art

[0002] A pump system is a complex system of mechanical devices that is used to transport fluids, such as water or other liquids. A pump system transports fluids by increasing the pressure (energy) of the fluid. Different types of pumps have different working principles. For example, a centrifugal pump transports fluids by generating centrifugal force through the rotating impeller, while a positive displacement pump transports fluids by periodically adding energy to a certain amount of water. The main parameters of a pump system include flow rate, head, speed, input power, output power and efficiency.

[0003] In a water pump system, flow rate and head are two key performance parameters, and their measurement methods are also crucial. The measurement of flow rate mainly includes the standard orifice flowmeter method and the weighing method. Electromagnetic flowmeter, ultrasonic flowmeter and other measuring instruments can also be used for flow measurement. The measurement of head mainly includes the pressure gauge and vacuum gauge method, pressure sensor method and direct observation method.

[0004] However, the current measurement methods still have certain defects. Among the flow measurement methods, traditional methods such as the standard orifice flowmeter method are simple and reliable, but the accuracy is relatively low. Although the weighing method has high accuracy, it is usually only applicable to small flows or occasions that require precise measurement, and the operation is relatively complicated. Although measuring instruments such as electromagnetic flowmeters and ultrasonic flowmeters are accurate and easy to operate, they are expensive and may increase the overall investment of the water pump system. Among the head measurement methods, pressure gauges and vacuum gauges are commonly used, but they are affected by factors such as instrument accuracy and reading errors, which may lead to inaccurate head measurement results. Although the pressure sensor method has the advantages of accurate measurement and good real-time performance, the accuracy and stability of the sensor itself will also affect the accuracy of the measurement results. The direct observation method is only applicable to small or simple water pump systems, and the error is large, which cannot meet the needs of high-precision measurement. Summary of the invention

[0005] The purpose of the present invention is to provide a sensorless flow and head detection method for a water pump system, which solves the problem of measuring flow and head data without a sensor, reduces the cost of water pump system performance testing, and has high measurement accuracy.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A sensorless flow and head detection method for a water pump system, the sensorless flow and head detection method for a water pump system comprising: Calibration stage: collect data at different speeds, change the valve opening of the water pump to measure the flow value, power value and head value of the water pump, and fit the power-flow equation and head-flow equation corresponding to each speed; The rated flow of the water pump is discretized according to the accuracy requirement to obtain a flow value array, each flow value in the flow value array is substituted into all power-flow equations to obtain a power value and a corresponding speed, and a power-speed equation corresponding to each flow value is obtained by fitting; Detection stage: Obtain the known speed and power values ​​of the water pump and substitute them into all power-speed equations to determine the flow value range, and perform linear compensation within the flow value range to obtain the flow value. Substitute the flow value calculated by linear compensation into the head-flow equation at the corresponding speed to obtain the head value.

[0007] Several optional methods are also provided below, but they are not intended to be additional limitations on the above-mentioned overall solution, but are merely further supplements or preferences. Under the premise that there are no technical or logical contradictions, each optional method can be combined with the above-mentioned overall solution separately, and multiple optional methods can also be combined.

[0008] Preferably, the step of discretizing the rated flow of the water pump according to the accuracy requirement to obtain a flow value array includes: According to the accuracy requirement, take equal parts that are greater than or equal to the accuracy requirement to divide the rated flow into equal parts to obtain a flow value array.

[0009] Preferably, the step of obtaining the known speed value and power value of the water pump and substituting them into all power-speed equations to determine the flow value range includes: The initialization power upper limit is the maximum power of the water pump, and the initialization power lower limit is the minimum power of the water pump; Take a power-speed equation corresponding to a flow value, substitute the known speed value into the power-speed equation, and obtain the power value corresponding to the flow value; If the calculated power value is less than the known power value, and the calculated power value is closer to the known power value than the power lower limit, the power lower limit is updated to the calculated power value, and the power-speed equation corresponding to the next flow value is taken to calculate the power value and updated until the calculation of all power-speed equations is completed; If the calculated power value is greater than the known power value, and the calculated power value is closer to the known power value than the power upper limit, the power upper limit is updated to the calculated power value, and the power-speed equation corresponding to the next flow value is taken to calculate the power value and updated until the calculation of all power-speed equations is completed; If the calculated power value is equal to the known power value, both the upper power limit and the lower power limit are updated to the calculated power value, and the update of the upper power limit and the lower power limit is terminated; According to the corresponding relationship between the flow value and the power-speed equation, the flow value corresponding to the upper power limit is obtained as the flow upper limit, and the flow value corresponding to the lower power limit is obtained as the flow lower limit, thereby completing the flow value range determination.

[0010] Preferably, the linear compensation within the flow value range to obtain the flow value includes: In the formula, is the flow value obtained by linear compensation, Indicates the flow rate limit corresponding to the power limit. Indicates the lower flow limit corresponding to the power lower limit, represents a known power value, Indicates the lower power limit, Indicates the power cap.

[0011] Preferably, the step of substituting the calculated flow value into the head-flow equation at the corresponding speed to obtain the head value comprises: Traverse the speed values ​​corresponding to the head-flow equation. If there is a speed value corresponding to the head-flow equation that is equal to the known speed value, directly substitute the flow value calculated by linear compensation into the head-flow equation at the corresponding speed to obtain the head value. Otherwise, take the speed values ​​corresponding to the two head-flow equations closest to the known speed value, and take the one greater than the known speed value as the upper speed limit, and the other as the lower speed limit; Substitute the flow value obtained by linear compensation calculation into the head-flow equation corresponding to the upper limit of the speed to obtain the upper limit of the head. Substitute the flow value obtained by linear compensation calculation into the head-flow equation corresponding to the lower limit of the speed to obtain the lower limit of the head. Perform linear compensation within the range of the upper limit and the lower limit of the head to obtain the head value.

[0012] Preferably, the linear compensation within the range of the upper limit and the lower limit of the lift to obtain the lift value comprises: In the formula, Indicates the lift value obtained by linear compensation, Indicates the upper limit of lift. Indicates the lower limit of lift. represents a known speed value, Indicates the lower speed limit. Indicates the upper speed limit.

[0013] The present invention also provides a sensorless flow and head detection device for a water pump system, comprising a processor and a memory storing a plurality of computer instructions, wherein the computer instructions, when executed by the processor, implement the steps of the sensorless flow and head detection method for a water pump system.

[0014] The present invention provides a sensorless flow and head detection method and device for a water pump system. Without installing pressure sensors, flow meters and other sensors, the real-time flow and head data of the current water pump system can be calculated in the original water pump system by obtaining the speed and power data without increasing the hardware cost. The defects of the existing flow and head data obtained based on flow meters or pressure sensors are overcome. A method for measuring flow and head data without sensors is proposed, which reduces the cost of water pump system performance testing and ensures a higher measurement accuracy based on data fitting and compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a flow chart of a sensorless flow and head detection method for a water pump system. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0018] This embodiment provides a sensorless flow and head detection method for a water pump system, which is applied to a water pump system. The water pump system has valves, motors and other components. The busbar of the motor drive part has a current sampling and a voltage sampling, which can be used to calculate the overall power P of the water pump system. In the motor loop control part, the current speed N of the water pump system can be estimated through an estimator. The method of the present invention is mainly divided into a calibration stage and a detection stage. The calibration stage includes sample collection, curve fitting and quadratic fitting after equation conversion, and the detection stage mainly includes mean linear compensation.

[0019] like Figure 1 As shown, the sensorless flow and head detection method for a water pump system implemented in this embodiment includes the following steps: Step 1: On the measuring table, collect data at different speeds, change the valve opening, and measure the flow value Q1~Qn, power value P1~Pn and head value H1~Hn of the corresponding water pump based on the real-time flow.

[0020] The measuring bench used here is a test bench for the calibration phase. A water pump system is arranged on the measuring bench for actual data collection in order to fit the equation that is closest to the real data, where n is the number of samples, and there are n sample data at each speed.

[0021] Step 2: Based on the sample data, multiple power-flow equations P(Q) and head-flow equations H(Q) at different speeds are fitted.

[0022] Take the flow value Q1~Qn and power value P1~Pn at a certain speed, use the existing data fitting method to fit the power-flow equation P(Q) at the speed, fit at different speeds, and obtain multiple power-flow equations P(Q) at different speeds. When collecting samples, by comparing the data characteristics, it is found that at the same speed, the increase in flow and power increases at almost the same ratio. Therefore, this embodiment fits the power-flow equation P(Q) to a first-order equation. In this embodiment, the power is y and the flow is x. The format of the multiple power-flow equations P(Q) at different speeds obtained by fitting is shown in Table 1.

[0023] Table 1 P(Q) format of multiple power-flow equations at different speeds Speed x coefficient constant N0 k0 b0 N1 k1 b1 N2 k2 b2 N3 k3 b3 N4 k4 b4 Take the flow value Q1~Qn and the head value H1~Hn at a certain speed, use the existing data fitting method to fit the head-flow equation H(Q) at the speed, fit at different speeds, and obtain multiple head-flow equations H(Q) at different speeds. By comparing the data characteristics, it is found that at the same speed, the relationship between flow and head satisfies the quadratic equation. Therefore, this embodiment fits the head-flow equation H(Q) into a quadratic equation. In this embodiment, the head is y and the flow is x. The formats of the multiple head-flow equations H(Q) at different speeds obtained by fitting are shown in Table 2.

[0024] Table 2 Multiple head-flow H(Q) formats at different speeds Speed <![CDATA[x 2 Coefficient]]> x coefficient constant N0 a0 b0 c0 N1 a1 b1 c1 N2 a2 b2 c2 N3 a3 b3 c3 N4 a4 b4 c4 It should be noted that the above are the linear fitting and polynomial fitting results provided in this embodiment. In other embodiments, the power-flow equation P(Q) and the head-flow equation H(Q) can be obtained based on other data fitting methods. The equations are not limited to linear equations or quadratic equations, and the actual data fitting results shall prevail.

[0025] Step 3: Based on the equation fitted in step 2, the rated flow of the water pump is discretized according to the average principle and the accuracy requirement to obtain an arithmetic flow value array. Each flow value in the flow value array is substituted into the power-flow equation P(Q), and multiple sets of speed and power data under different flow rates can be calculated.

[0026] When the rated flow is discretized, it is preferred to use equal discretization. Since the final detection error of the present invention is much smaller than the accuracy requirement, when the rated flow is divided into equal parts using the accuracy requirement, the accuracy requirement can be directly used as the equal part, or the calculation can be simplified to take a value greater than the accuracy requirement as the equal part for the equal division operation. When taking the equal parts, it can be directly set based on experience, it can be determined by trial and error, or it can be determined by fitting the relationship between the adopted accuracy requirement and the accuracy error of the final output value, which is not limited in this embodiment.

[0027] For each flow value, all power-flow equations P(Q) are substituted to obtain multiple sets of power values ​​corresponding to different speeds, that is, multiple sets of speed and power value data corresponding to each flow value are obtained.

[0028] Step 4: According to the speed and power value data calculated in step 3, multiple power-speed equations P(N) under different flow rates are fitted.

[0029] Take multiple groups of speed and power value data under a flow value, use the existing data fitting method to fit the power-speed equation P(N) under the flow value, and fit different flow values ​​to obtain multiple power-speed equations P(N) under different flow values. By comparing the data characteristics, it is found that under the same flow value, the relationship between power and speed satisfies a cubic equation. Therefore, in this embodiment, the power-speed equation P(N) is fitted into a cubic equation. In this embodiment, the power is y and the speed is x. The format of the multiple power-speed equations P(N) under different flow values ​​obtained by fitting is shown in Table 3.

[0030] Table 3 Format of multiple power-speed equations P(N) at different flow values flow <![CDATA[x 3 Coefficient]]> <![CDATA[x 2 Coefficient]]> x coefficient constant L0 a0 b0 c0 d0 L1 a1 b1 c1 d1 L2 a2 b2 c2 d2 L3 a3 b3 c3 d3 L4 a4 b4 c4 d4 It should be noted that the above is the polynomial fitting result provided in this embodiment. In other embodiments, the power-speed equation P(N) can be obtained based on other data fitting methods. The equation is not limited to a cubic equation, and the actual data fitting result shall prevail.

[0031] Step 5: By using the known speed and power, the real-time speed and power are substituted into all the power-speed equations P(N) to determine the flow value Q range, and then linear compensation is performed within the range to calculate the flow value.

[0032] Step 5.1: Initialize power cap The maximum power of the water pump, initializing the lower power limit The maximum power and the minimum power depend on the water pump motor and are determined by the hardware structure, which will not be described in detail in this embodiment.

[0033] Step 5.2: Take a power-speed equation corresponding to a flow value, substitute the known speed value into the power-speed equation P(N), and obtain the power value corresponding to the flow value.

[0034] Step 5.3: If the calculated power value is less than the known power value, and the calculated power value is closer to the known power value than the power lower limit, then the power lower limit is increased. Update to the calculated power value. If there is a power-speed equation P(N) that is not involved in the calculation, take the power-speed equation P(N) corresponding to the next flow value and return to step 5.2, otherwise execute step 5.4.

[0035] If the calculated power value is greater than the known power value, and the calculated power value is closer to the known power value than the power cap, the power cap is set. Update to the calculated power value. If there is a power-speed equation P(N) that is not involved in the calculation, take the power-speed equation P(N) corresponding to the next flow value and return to step 5.2, otherwise execute step 5.4.

[0036] If the calculated power value is equal to the known power value, the power cap is set. and power lower limit The power cap is ended. and power lower limit To update, proceed to step 5.4.

[0037] Otherwise, when none of the above three conditions are met, the currently calculated power value is discarded. If there is a power-speed equation P(N) that is not involved in the calculation, the power-speed equation P(N) corresponding to the next flow value is taken, and return to step 5.2, otherwise execute step 5.4.

[0038] In order to improve the reliability of data calculation and avoid the influence of abnormal data, the power upper limit is obtained. and power lower limit After that, you can also set the power cap and power lower limit Perform validity verification, including data type verification, data length verification or range verification, etc. If the validity verification passes, continue with the subsequent steps, otherwise it is considered that the current real-time speed and power are abnormal, end this calculation, and discard the current real-time speed and power.

[0039] Step 5.4: According to the corresponding relationship between the flow value and the power-speed equation, the power upper limit is obtained. The corresponding flow value is used as the flow upper limit , get the power lower limit The corresponding flow value is used as the flow lower limit , complete the flow value range determination.

[0040] Step 5.5: Perform linear compensation within the flow value range to obtain the flow value, including: In the formula, is the flow value obtained by linear compensation, Represents a known power value.

[0041] Step 6: Substitute the flow value calculated in step 5 into the head-flow equation H(Q) fitted in step 2 to determine the range of the head H. Then, linear compensation is performed within the range to calculate the accurate head value.

[0042] Traverse the speed values ​​corresponding to the head-flow equation H(Q). If there is a speed value corresponding to the head-flow equation H(Q) that is equal to the known speed value, directly substitute the flow value calculated by linear compensation into the head-flow equation H(Q) at the corresponding speed to obtain the head value.

[0043] Otherwise, take the speed values ​​corresponding to the two head-flow equations closest to the known speed value, and take the speed value greater than the known speed value as the speed upper limit. , and the other as the lower speed limit .

[0044] Substitute the flow value obtained by linear compensation calculation into the speed upper limit The corresponding head-flow equation gives the upper limit of the head , substitute the flow value obtained by linear compensation calculation into the lower speed limit The corresponding head-flow equation gives the lower limit of the head , and perform linear compensation within the upper and lower limits of the lift to obtain the lift value: In the formula, Indicates the lift value obtained by linear compensation, Indicates the upper limit of lift. Indicates the lower limit of lift. represents a known speed value, Indicates the lower speed limit. Indicates the upper speed limit.

[0045] In order to prove the effectiveness of the method of the present invention, this embodiment uses flow calculation as an example to conduct an experiment. The water pump parameters used in the experiment are: power 90W, speed 4500rpm, rated flow 75L / min, and rated head 9 meters.

[0046] The experimental steps are as follows: 500 rpm, 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm and 4500 rpm are used as the speeds set for data collection, and 11 flow values ​​Q and power values ​​P are measured at each speed by changing the valve opening of the water pump. In the equation fitting, the value of x should not be too large, so as to avoid the equation coefficient being too small to increase the error. Therefore, in this embodiment, the collected flow value Q is reduced by 10 times, and the collected speed is reduced by 100 times before curve fitting. The power (y)-flow (x) equation obtained by fitting is a quadratic equation, and the coefficients are recorded as shown in Table 4.

[0047] Table 4 Power-flow equation coefficient table Speed ​​(rpm) <![CDATA[x 2 Coefficient]]> x coefficient constant 5 0 0.1817 2.2046 10 -0.0616 0.8955 3.057 15 -0.1069 2.0369 4.8283 20 -0.1956 3.9346 7.2611 25 -0.1673 5.6161 11.894 30 -0.2181 8.2945 17.859 35 0 9.795 26.04 40 0 13.456 38.352 45 0 16.612 51.977 The accuracy requirement of flow detection is set to 3.3 L / min. Under the premise of meeting the accuracy requirement, the equal volume is taken as 8.333 L / min according to the empirical value. Since the flow rate is reduced by 10 times in the experiment, the rated flow rate used for calculation is 7.5 L / min, so the final equal volume in the experiment is 0.8333 L / min, and the discretized flow value array is {0, 0.8333, 1.6667, 2.5, 3.3333, 4.1667, 5, 5.8333, 6.6667, 7.5}. Each flow value is substituted into all the power-flow equations in Table 4 to obtain the power value and the corresponding speed, and the power (y)-speed (x) equation corresponding to each flow value is fitted as a quadratic equation, and the coefficients are recorded as shown in Table 5.

[0048] Table 5 Power-speed equation coefficient table Flow rate (L / min) <![CDATA[x 2 Coefficient]]> x coefficient constant 0 0.042 -0.9771 9.3821 0.8333 0.0476 -0.9188 8.9349 1.6667 0.0539 -0.8911 8.6277 2.5 0.0608 -0.894 8.4607 3.3333 0.0683 -0.9274 8.4338 4.1667 0.0765 -0.9915 8.547 5 0.0853 -1.0862 8.8003 5.8333 0.0948 -1.2114 9.1938 6.6667 0.1049 -1.3673 9.7273 7.5 0.1157 -1.5538 10.401 In the detection stage, the known speed value and power value of the water pump are obtained. The actual flow value is recorded in the experiment at the same time. The speed value is reduced by 100 times and then substituted into all power-speed equations with the power value to determine the flow value range. Linear compensation is performed within the flow value range to obtain the flow value. The flow value directly obtained by linear compensation is also the flow value reduced by 10 times. For the convenience of comparison, the actual flow value recorded in this embodiment and the calculated flow value after amplification by 10 times are shown in Table 6.

[0049] Table 6 Actual flow value and calculated flow value record table Speed ​​(rpm) Actual power (W) Actual flow rate (L / min) Calculated flow value (L / min) Flow rate difference (L / min) 10 9.7 30.10 31.19 1.09 10 9.3 26.70 28.36 1.66 10 8.8 23.50 24.85 1.35 10 8.3 20.20 21.79 1.59 10 7.7 16.70 18.12 1.42 10 7.1 13.40 14.72 1.32 10 6.5 10.20 11.49 1.29 10 5.9 6.90 8.26 1.36 10 5.2 3.40 4.85 1.45 It can be seen from Table 6 that when the accuracy requirement of flow detection is set to 3.3 L / min, the method of the present invention can not only quickly and easily obtain the flow value, but also the difference between the calculated flow value and the actual flow value is much smaller than the accuracy requirement, that is, the method of the present invention has high measurement accuracy.

[0050] In another embodiment, the present invention also provides a sensorless flow and head detection device for a water pump system, comprising a processor and a memory storing a plurality of computer instructions, wherein the computer instructions, when executed by the processor, implement the steps of the sensorless flow and head detection method for a water pump system.

[0051] For the specific limitations on the sensorless flow and head detection device for a water pump system, please refer to the limitations on the sensorless flow and head detection method for a water pump system in the above text, which will not be repeated here.

[0052] The memory and the processor are electrically connected directly or indirectly to achieve data transmission or interaction. For example, these elements can be electrically connected to each other through one or more communication buses or signal lines. The memory stores a computer program that can be run on the processor, and the processor implements the method of the present invention by running the computer program stored in the memory.

[0053] The memory may be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), etc. The memory is used to store a program, and the processor executes the program after receiving an execution instruction.

[0054] The processor may be an integrated circuit chip with data processing capabilities. The above-mentioned processor may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc. The methods, steps and logic block diagrams disclosed in the embodiments of the present invention may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0055] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0056] The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A sensorless flow and head detection method for a water pump system, characterized in that: The sensorless flow and head detection method for a water pump system comprises: Calibration stage: collect data at different speeds, change the valve opening of the water pump to measure the flow value, power value and head value of the water pump, and fit the power-flow equation and head-flow equation corresponding to each speed; The rated flow of the water pump is discretized according to the accuracy requirement to obtain a flow value array, each flow value in the flow value array is substituted into all power-flow equations to obtain a power value and a corresponding speed, and a power-speed equation corresponding to each flow value is obtained by fitting; Detection stage: Obtain the known speed and power values ​​of the water pump and substitute them into all power-speed equations to determine the flow value range, and perform linear compensation within the flow value range to obtain the flow value. Substitute the flow value calculated by linear compensation into the head-flow equation at the corresponding speed to obtain the head value.

2. The sensorless flow and head detection method for a water pump system according to claim 1, characterized in that: The method of discretizing the rated flow of the water pump according to the accuracy requirement to obtain a flow value array includes: According to the accuracy requirement, take equal parts that are greater than or equal to the accuracy requirement to divide the rated flow into equal parts to obtain a flow value array.

3. The sensorless flow and head detection method for a water pump system according to claim 1, characterized in that: The known speed and power values ​​of the water pump are obtained and substituted into all power-speed equations to determine the flow value range, including: The initialization power upper limit is the maximum power of the water pump, and the initialization power lower limit is the minimum power of the water pump; Take a power-speed equation corresponding to a flow value, substitute the known speed value into the power-speed equation, and obtain the power value corresponding to the flow value; If the calculated power value is less than the known power value, and the calculated power value is closer to the known power value than the power lower limit, the power lower limit is updated to the calculated power value, and the power-speed equation corresponding to the next flow value is taken to calculate the power value and updated until the calculation of all power-speed equations is completed; If the calculated power value is greater than the known power value, and the calculated power value is closer to the known power value than the power upper limit, the power upper limit is updated to the calculated power value, and the power-speed equation corresponding to the next flow value is taken to calculate the power value and updated until the calculation of all power-speed equations is completed; If the calculated power value is equal to the known power value, both the upper power limit and the lower power limit are updated to the calculated power value, and the update of the upper power limit and the lower power limit is terminated; According to the corresponding relationship between the flow value and the power-speed equation, the flow value corresponding to the upper power limit is obtained as the flow upper limit, and the flow value corresponding to the lower power limit is obtained as the flow lower limit, thereby completing the flow value range determination.

4. The sensorless flow and head detection method for a water pump system according to claim 3, characterized in that: The linear compensation within the flow value range to obtain the flow value includes: In the formula, is the flow value obtained by linear compensation, Indicates the flow rate limit corresponding to the power limit. Indicates the lower flow limit corresponding to the power lower limit, represents a known power value, Indicates the lower power limit, Indicates the power cap.

5. The sensorless flow and head detection method for a water pump system according to claim 1, characterized in that: Substituting the calculated flow value into the head-flow equation at the corresponding speed to obtain the head value includes: Traverse the speed values ​​corresponding to the head-flow equation. If there is a speed value corresponding to the head-flow equation that is equal to the known speed value, directly substitute the flow value calculated by linear compensation into the head-flow equation at the corresponding speed to obtain the head value. Otherwise, take the speed values ​​corresponding to the two head-flow equations closest to the known speed value, and take the one greater than the known speed value as the upper speed limit, and the other as the lower speed limit; Substitute the flow value obtained by linear compensation calculation into the head-flow equation corresponding to the upper limit of the speed to obtain the upper limit of the head. Substitute the flow value obtained by linear compensation calculation into the head-flow equation corresponding to the lower limit of the speed to obtain the lower limit of the head. Perform linear compensation within the range of the upper limit and the lower limit of the head to obtain the head value.

6. The sensorless flow and head detection method for a water pump system according to claim 5, characterized in that: The linear compensation within the range of the upper limit and the lower limit of the lift to obtain the lift value includes: In the formula, Indicates the lift value obtained by linear compensation, Indicates the upper limit of lift. Indicates the lower limit of lift. represents a known speed value, Indicates the lower speed limit. Indicates the upper speed limit.

7. A sensorless flow and head detection device for a water pump system, comprising a processor and a memory storing a plurality of computer instructions, characterized in that: When the computer instructions are executed by the processor, the steps of the sensorless flow and head detection method for a water pump system described in any one of claims 1 to 6 are implemented.

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