System and method for intelligently controlling pressure in alternate drip irrigation area based on head loss mapping

Abstract

The invention discloses a drip irrigation and rotation irrigation area pressure intelligent control system and method based on head loss mapping, and belongs to the technical field of agricultural irrigation. The system comprises a pump station, a partition valve, a controller, a head pressure sensor and a pressure loss database; the pressure loss database stores the pressure loss and compensation parameters of each alternate irrigation area for the controller to read the alternate irrigation area and pressure demand data; the partition valve provides a rotation irrigation area address signal for the controller; the controller inquires corresponding pressure demand data from the database according to the pressure demand data, and calculates and issues a head target pressure set value to the pump station; the pump station receives the instruction and stabilizes the outlet pressure within a set range through frequency conversion adjustment; the head pressure sensor monitors the pressure in real time and feeds back the pressure to the controller. According to the technical scheme, working conditions can be automatically recognized, parameters can be calculated, closed-loop adjustment can be completed, and continuity and reliability are improved while labor intensity is reduced; by adjusting the rotating speed of the pump station, the output pressure of the water pump is accurately matched with actual requirements, and energy consumption is reduced.

Description

Technical Field

[0001] This invention belongs to the field of agricultural irrigation technology, and specifically relates to an intelligent control system and method for pressure control in drip irrigation districts based on head loss mapping. Background Technology

[0002] Currently, in large-scale drip irrigation systems, the distance between different irrigation zones and the pump station is significant, and in hilly and mountainous areas, the varying altitudes of these zones further exacerbate the problem, leading to large differences in outlet water pressure. Irrigation zones farther from the pump station (or at higher elevations) experience severe pressure attenuation, while those closer (or at lower elevations) may face pressure redundancy. This pressure gradient distribution results in inconsistent head pressure requirements across different irrigation zones. Traditional solutions typically involve installing multiple pressure sensors at key nodes for real-time monitoring, but this is costly in terms of hardware deployment and maintenance, and the sensors are susceptible to environmental interference, exhibiting insufficient long-term stability. Alternatively, a fixed head pressure setting can be used, uniformly setting a baseline pressure value, but this cannot dynamically adapt to the actual needs of different irrigation zones, resulting in energy waste in near-end areas, uneven irrigation in far-end areas, and overall low water resource utilization efficiency. Furthermore, a fixed pressure mode may cause frequent pump start-ups and shutdowns, further increasing equipment wear and operating costs.

[0003] No effective solution to the above problems has yet been found. Summary of the Invention

[0004] The technical problem to be solved by this invention is the inconsistent head pressure required by each irrigation zone due to the difference in distance (height) between the irrigation zone and the pump station. It provides an intelligent control system and method for drip irrigation irrigation zone pressure based on head loss mapping. By calculating the head loss and height difference along the pipeline of each irrigation zone, the pressure demand mapping data from the irrigation zone to the head station is obtained. The pump station pressure is automatically adjusted when switching irrigation. Stable pressure supply can still be achieved without the need to install multiple pressure sensors, thereby improving irrigation uniformity and reducing energy consumption.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A smart pressure control system for drip irrigation districts based on head loss mapping includes pump stations, zone valves, controllers, head pressure sensors, and a pressure loss database. The pressure loss database stores the pipeline head loss value, local head loss value and elevation loss parameter corresponding to each irrigation zone, so that the controller can read the "irrigation zone - pressure demand" data when switching irrigation zones. The controller is used to identify the currently activated irrigation zone and query the corresponding total head loss value H from the "Irrigation Zone - Pressure Demand" data. i According to the preset end working pressure P end Generate and issue the head target pressure setpoint Pset,i The adjustment command is sent to the pumping station; The zone valve is used to control the opening and closing status of each irrigation zone and to provide the address signal of the irrigation zone to the controller; The pumping station receives adjustment commands from the controller and, through a frequency converter, provides head pressure to the activated irrigation area, maintaining the head pressure at the target head pressure setpoint P. set,i Within the set range; The head pressure sensor is used to monitor the head pressure at the pump station outlet in real time and feed the head pressure signal back to the controller.

[0006] Preferably, the total head loss value H i Including head loss value HW i and elevation loss value ΔH i ; The head loss value HW i Including head loss along the friction fretting (HF) i and local head loss value HJ i .

[0007] Preferably, the pressure loss database calculates the head loss along the pipeline segment by segment according to the Hazen–Williams formula for each irrigation area i, including the main and branch pipe segments. The calculation formula is: in: : Head loss along the pipe section, in meters of water column; L: The length of the pipe section, in meters; Q: The volumetric flow rate through this pipe section, in cubic meters per second; D: Pipe inner diameter, in meters; C: Hazen–Williams roughness coefficient, a dimensionless constant; The head loss value along the friction HF i The head loss along each pipeline (h) f The sum calculation, that is: Head loss value HW i for: HW i =HF i +HJ i Among them, HJ i HJ represents the local head loss value. i ≈ (10 ± 0.5)%HF i ; Elevation loss value ΔHi for: ΔH i =Hi end Hi start Among them, Hi end It is the elevation of the endpoint, Hi start It is the elevation of the starting point; Total head loss value H i for: H i =HW i +ΔH i .

[0008] Preferably, the head target pressure setpoint P set,i for: P set,i =P end +H i +M Among them, P end To preset the terminal working pressure, H i Let M be the total head loss value of irrigation area i, and M be the safety margin.

[0009] A method for implementing an intelligent pressure control system for drip irrigation districts based on head loss mapping includes the following steps: S1: The controller reads the solenoid valve control signal of the zone valve, identifies the irrigation zone i that needs to be irrigated, and proceeds to step S2; S2: The controller queries the pressure loss database for the total head loss value H corresponding to irrigation zone i based on the zone valve number. i Proceed to step S3; S3: The controller determines the preset end working pressure P. end Total head loss value H i The head target pressure setpoint P for irrigation zone i in this cycle was calculated. set,i The controller generates a pressure regulation command and sends it to the pump station, proceeding to step S4; S4: The pump station receives the pressure regulation command from the controller and adjusts the pump output pressure through the frequency converter to make the head pressure value of the pump station approach the head target pressure set value P. set,i Perform stable irrigation operations and proceed to step S5; S5: During irrigation, the head pressure sensor monitors the head pressure at the pump station outlet in real time and feeds back the head pressure signal to the controller, then proceeds to step S6; S6: The controller will synchronously collect the pump station's operating frequency N(t), main pipeline flow rate Q(t), and system stable operating parameters N in real time. stable,i Q stable, The absolute differences ΔN and ΔQ of i and the deviation ΔN from the pump station operating frequency threshold.threshold , Main flow rate threshold deviation ΔQ threshold Compare and determine whether the normal operating conditions are met; If ΔQ≤ΔQ threshold And ΔN≤ΔN threshold If the condition is met, proceed to step S7. If ΔQ>ΔQ threshold , or ΔN>ΔN threshold If so, it is determined that there is an abnormal working condition, and the process proceeds to step S8; S7: The controller is in self-learning mode, correcting the total head loss value H. i And the corrected H i Update to the pressure loss database; after irrigation of irrigation zone i is completed, switch irrigation zones, open the valve of the next zone, close the valve of irrigation zone i, and return to step S1; S8: Enter protection mode, stop learning and correcting the head loss value Hi along the flow path, alarm and control to stop irrigation.

[0010] Preferably, in step S7, when the system is in self-learning mode, the system maintains the target head pressure P. set,i Under these conditions, when the actual operating flow rate Q(t) of the main pipeline is higher than the stable operating flow rate Qt... stable,i When the actual total head loss of the system is less than the total head loss value Hi recorded in the pressure loss database, then the total head loss value H is reduced. i When the actual operating flow rate Q(t) of the main pipeline is lower than the stable operating flow rate Qt... stable,i When this happens, the total head loss value H is increased. i .

[0011] The present invention adopts the above technical solution and has the following advantages compared with the prior art: 1. The technical solution of this invention adjusts the pump station speed by using a frequency converter, so that the water pump output pressure is precisely matched with the actual demand, avoiding energy waste in non-design conditions and significantly reducing system energy consumption.

[0012] 2. The entire process of this invention requires no manual intervention. The system automatically identifies the working conditions, calculates parameters, and completes closed-loop adjustments. This not only significantly reduces labor intensity but also minimizes the risk of human error, ensuring the continuity and reliability of irrigation operations. 3. The technical solution of this invention can adapt to the differences in terrain, area, pipeline layout, etc. of different irrigation areas, and has the ability to handle complex irrigation networks, and has strong versatility. Attached Figure Description

[0013] Appendix Figure 1This is a schematic diagram of the working principle of the intelligent control system for drip irrigation wheel pressure in the irrigation area based on head loss mapping in an embodiment of the present invention; Appendix Figure 2 This is a flowchart of the intelligent pressure control method for drip irrigation wheel irrigation area based on head loss mapping in an embodiment of the present invention. Detailed Implementation

[0014] The present invention will be further described below. Those skilled in the art should understand through the following embodiments that these embodiments are not intended to limit the technical solution of the present invention, but merely to fully illustrate how to implement it.

[0015] Examples, such as Figure 1 As shown, the intelligent control system for drip irrigation district pressure based on head loss mapping includes a pump station, zone valves, controllers, a pressure loss database, and a head pressure sensor.

[0016] The pumping station is used to adjust the water supply pressure of the irrigation system according to the target headwater pressure setpoint issued by the controller. The pumping station is equipped with a frequency converter, which receives adjustment commands from the controller and uses the frequency converter to provide headwater pressure to the activated irrigation areas, maintaining the headwater pressure at the target headwater pressure setpoint P. set,i Within the set range; at the same time, the pump station receives feedback signals from the head pressure sensor to realize automatic adjustment and stable control of the head pressure.

[0017] The zone valve is used to control the opening and closing status of each irrigation zone. The address signal of the valve enables the controller to identify the irrigation zone that is currently irrigated, realizing the sequential switching between irrigation zones, so that only one irrigation zone is irrigated at any given time. The zone valve is a solenoid valve.

[0018] The pressure loss database stores the pipeline head loss value, local head loss value and elevation loss parameter corresponding to each irrigation zone, and forms a "irrigation zone - pressure demand" mapping relationship based on the pre-calculated hydraulic results, so that the controller can read the "irrigation zone - pressure demand" data when switching irrigation zones.

[0019] The head pressure sensor is used to monitor the head pressure at the pump station outlet in real time and feed the pressure signal back to the controller, so that the controller outputs adjustment commands to the frequency converter according to the pressure deviation, thereby realizing closed-loop automatic adjustment of the head pressure of the pump station and providing pressure anomaly monitoring and protection during the switching of irrigation zones.

[0020] The controller identifies the currently activated irrigation zone and retrieves the corresponding total head loss value H from the "Irrigation Zone - Pressure Demand" data based on the zone valve number. i The controller operates based on the preset end working pressure P. end Generate the head target pressure setpoint P for the corresponding irrigation area. set,iIt also sends pressure regulation commands to the pumping station.

[0021] During the installation phase, the system assigns a unique valve number to each zone valve and stores the corresponding hydraulic characteristics, such as pipe length, pipe diameter, local loss parameters, and terrain elevation differences, in the pressure loss database. Each irrigation zone is equipped with a soil moisture sensor that measures soil moisture content and transmits the signal to the controller. The controller controls the opening and closing of the zone valves based on the received soil moisture information. When soil moisture falls below a set threshold, the zone valve automatically opens. The controller calculates the irrigation volume based on preset parameters such as upper and lower soil moisture limits, irrigation wetting ratio, soil bulk density, and target irrigation depth. Irrigation stops when the calculated irrigation volume is reached. The controller automatically identifies the irrigation zone requiring irrigation via the valve's address signal. After irrigation of the current zone is completed, it switches to the next zone until all irrigation zones are completed, achieving automatic irrigation switching between zones.

[0022] Specifically, the controller identifies the currently open irrigation zone by reading the solenoid valve switching signals of the zoning valves in each irrigation zone. Based on the preset mapping relationship between valve numbers and the spatial location of the irrigation zone, it determines the main pipe length and head loss parameters along the pipeline between the irrigation zone and the pumping station, and then selects the corresponding total head loss value H from the pressure loss database. i .

[0023] The controller determines the system's operating status based on operating data such as the pump station's frequency converter operating frequency, main flow rate, and headwater pressure to identify whether the system is under normal operating conditions. When the system is determined to be under normal operating conditions, the controller stabilizes the headwater pressure at the target pressure setpoint P. set,i Under the premise of collecting the actual operating frequency, output power or main flow of the pumping station, and comparing it with the design operating parameters of the irrigation area, the total head loss value H is determined based on its long-term deviation. i The system is updated to adaptively correct the head loss parameters along the route; when the operating data meets the abnormal operating condition judgment conditions, the system transitions from normal operating condition to abnormal operating condition, and the controller stops the total head loss value H. i The system corrects and learns, outputs alarm information, and controls the cessation of irrigation. Abnormal operating conditions include pipe rupture, system leakage, dripper blockage, or filter clogging.

[0024] When the controller detects the opening signal of a certain zone valve, it queries the pressure loss database for the corresponding irrigation zone i location and total head loss value H based on the zone valve number. i And generate the head target pressure setpoint P for irrigation zone i. set,i Then control the pump station to output the corresponding head target pressure setpoint P set,iSimultaneously, the controller automatically corrects the total head loss value H based on the operating frequency and preset parameters. i It can identify abnormal operating conditions such as blockages and pipe bursts along the pipeline and develop self-learning capabilities.

[0025] Total head loss H in irrigation area i i Including head loss value HW i and elevation loss value ΔH i The head loss value HW i Including head loss along the friction fretting (HF) i and local head loss value HJ i Local head loss value HJ i According to the head loss value along the route HF i The elevation loss value ΔH is calculated as 10% ± 0.5%. i It is the potential energy of a fluid due to changes in its position and height. The irrigation area i is divided into flat, hilly and other terrains. ΔHi can be positive or negative. A positive result indicates flow from low to high, and a negative result indicates flow from high to low.

[0026] The pressure loss database of this invention pre-stores the Hazen-Williams coefficient C or absolute roughness k for different pipe materials, which is used to calculate the friction head loss HF value for irrigation zone i. i The Hazen–Williams formula was used to calculate the head loss h along the pipeline for each irrigation area i, corresponding to the main and branch pipe segments. f The friction head loss HF value for irrigation zone i is obtained by summing the values ​​according to the pipeline structure. i Total head loss value H i With the preset end working pressure P end Together they constitute the head target pressure setpoint P set,i The computational basis.

[0027] Specifically, under clean water and normal temperature conditions, the head loss along each pipeline is calculated using the Hazen–Williams empirical formula. The formula is: in: : Head loss along the pipe section, in meters of water column (m water column); L: The length of the pipe section, in meters (m); Q: The volumetric flow rate through this pipe section, expressed in cubic meters per second (m³ / s). D: Pipe inner diameter, in meters (m); C: Hazen–Williams roughness coefficient, a dimensionless constant.

[0028] For PVC / PE water pipes commonly used in agricultural irrigation, the Hazen–Williams coefficient C is preferably 140–150, with 140 or 145 being the preferred values; for steel pipes, cast iron pipes, and concrete pipes, the ranges shown in Table 1 are selected. Table 1 is a table of roughness coefficients for different pipe types.

[0029] Table 1 Pipe type Status / Description Hazen–Williams coefficient C (recommended) PVC pipes (rigid polyvinyl chloride for water supply) New pipe 145–155 (150 or 140–150 are commonly used) PE pipe (polyethylene drip irrigation / water supply pipe) New pipe 140–150 (140 is commonly used) HDPE pipe New pipe 135–145 Fiberglass reinforced plastic (FRP) pipe with smooth inner wall New pipe 150–160 copper pipes, brass pipes New pipe 130–140 galvanized steel pipe New pipe 120–130 Low carbon steel pipe / ordinary steel pipe New pipe 110–130 Ductile iron pipe New pipe 120–140 Ordinary cast iron pipe New pipe 100–120 Old cast iron pipes (with scale and corrosion) running for many years 80–100 Concrete pipe The surface is relatively smooth 110–130 Concrete pipe (rough, aged) Deposits / Roughness 90–110 asbestos cement pipe General situation 120–140 For a pipeline consisting of multiple sections of different diameters or materials, the friction head loss HF from the pumping station to the inlet of irrigation area i is... i The head loss along each pipeline (h) f The sum calculation, that is: Head loss value HW i for: HW i =HF i +HJ i Among them, HJ i HJ represents the local head loss value. i ≈ (10 ± 0.5)%HF i ; Elevation loss value ΔH i for: ΔH i =Hi end Hi start Among them, Hi end It is the elevation of the endpoint, Hi start It is the elevation of the starting point, in meters; Total head loss value H i for: H i =HW i +ΔH i Head target pressure setpoint P set,i Calculate according to the following formula: P set,i =P end +H i +M Among them, P end To preset the terminal working pressure, H i Let M be the total head loss value of irrigation area i, and M be the safety margin.

[0030] The controller periodically collects data on the headwater pressure Pmeas(t), pump station operating frequency N(t), main pipeline flow rate Q(t), and valve status of the zone valves during actual operation. After the irrigation in the rotating irrigation area i stabilizes, the headwater pressure P is calculated.stable,i Pump station operating frequency N stable,i (Including design flow rate), main pipeline flow rate Q stable,i (Including design frequency). The operating frequency N(t) of the pump station directly determines its head pressure Pmeas(t). The higher the operating frequency N(t), the greater the head pressure Pmeas(t), and the corresponding increase in the main pipeline flow rate Q(t). Conversely, the lower the operating frequency N(t), the smaller the head pressure Pmeas(t), and the corresponding decrease in the main pipeline flow rate Q(t).

[0031] Specifically, when switching irrigation zone i, the absolute difference in main pipeline flow rate ΔQ and the absolute difference in pump station operating frequency ΔN are respectively: ΔQ=|Q(t)-Q stable,i | ΔN=|N(t)-N stable,i | in: Q stable,i : The flow rate of the main pipeline during stable operation (including the design flow rate); N stable,i The operating frequency of a stable pumping station (including the design frequency); Preset pump station operating frequency threshold deviation ΔN within the controller threshold , Main flow rate threshold deviation ΔQ threshold The controller compares the absolute difference in flow rate ΔQ in the main pipeline with the main pipeline flow rate threshold ΔQ. threshold Compare the absolute difference in pump station operating frequency ΔN with the operating frequency threshold ΔN. threshold Comparison is used to determine the system's operating condition.

[0032] When ΔQ>ΔQ threshold , or ΔN>ΔN threshold If the controller determines that the system is in an abnormal operating condition, such as pipe rupture, drip tape detachment, large-scale leakage, dripper blockage, or filter blockage, the controller will enter an abnormal protection mode, and the system will stop monitoring the total head loss value H. i It learns and corrects errors, outputs alarms for abnormal operating conditions, and stops irrigation; When ΔQ≤ΔQ threshold And ΔN≤ΔN threshold If the controller determines that the system meets normal operating conditions, the controller enters self-learning mode, and the system corrects the total head loss value H. i The controller maintains the target pressure setpoint P at the pump station. set,i The system automatically corrects the total head loss value H of the corresponding irrigation area based on the deviation between the actual operating frequency, output power, or main pipeline flow rate and the preset main pipeline flow rate. i In order to develop self-learning ability.

[0033] like Figure 2 As shown, the method for an intelligent control system of drip irrigation district pressure based on head loss mapping includes the following steps: S1: The controller reads the solenoid valve control signal of the zone valve, identifies the irrigation zone i that needs to be irrigated, and proceeds to step S2; S2: The controller queries the pressure loss database for the total head loss value H corresponding to irrigation zone i based on the zone valve number. i Proceed to step S3; S3: The controller determines the preset end working pressure P. end Total head loss value H i The head target pressure setpoint P for irrigation zone i in this cycle was calculated. set,i The controller generates a pressure regulation command and sends it to the pump station, proceeding to step S4; S4: The pump station receives the pressure regulation command from the controller and adjusts the pump's output head pressure via the frequency converter, so that the head pressure value of the pump station approaches the head target pressure set value P. set,i Perform stable irrigation operations and proceed to step S5; S5: During irrigation, the head pressure sensor monitors the head pressure at the pump station outlet in real time and feeds back the head pressure signal to the controller, then proceeds to step S6; S6: The controller will synchronously collect the pump station's operating frequency N(t), main pipeline flow rate Q(t), and system stable operating parameters N in real time. stable,i Q stable,i The absolute differences ΔN and ΔQ and the deviation ΔN from the operating frequency threshold of the pumping station threshold , Main flow rate threshold deviation ΔQ threshold Compare and determine whether the system meets normal operating conditions; If ΔQ≤ΔQ threshold And ΔN≤ΔN threshold If the system meets the normal operating conditions, proceed to step S7. If ΔQ>ΔQ threshold , or ΔN>ΔN threshold If so, it is determined that the system has an abnormal operating condition, and the process proceeds to step S8; S7: The controller is in self-learning mode, and the system corrects the total head loss value H. i And the corrected H i Update to the pressure loss database; after irrigation of irrigation zone i is completed, switch irrigation zones, open the valve of the next zone, close the valve of irrigation zone i, and return to step S1; In self-learning mode, the system maintains the initial target pressure P. set,i Under these conditions, when the actual operating flow rate Q(t) of the main pipeline is higher than the stable operating flow rate Qt... stable,iWhen this occurs, it indicates that the actual total head loss of the system is less than the total head loss value H recorded in the pressure loss database. i This reduces the total head loss value H. i When the actual operating flow rate Q(t) of the main pipeline is lower than the stable operating flow rate Qt... stable,i When this happens, the total head loss value H is increased. i The corrected total head loss value H i Maintain the target head pressure P of the system set,i ; S8: The system transitions from normal to abnormal operation; the controller enters abnormal protection mode, and the system stops monitoring the total head loss value H. i It learns and corrects, alarms, and controls to stop irrigation.

[0034] Specifically, for example, a modern agricultural demonstration zone has a corn drip irrigation area of ​​300,000 square meters. The terrain is flat, and the plot is a rectangle with a length of 1,500 meters and a width of 200 meters. It is divided into 10 rotation irrigation areas, and the irrigation head is located in one corner of the plot.

[0035] The corn rows are spaced 1.2m apart, with drip irrigation tape laid in each row. The drippers are spaced 30cm apart and the flow rate per dripper is 0.8L / h. The main pipe is a 110mm diameter PVC pipe laid along the length of the plot.

[0036] Calculate the irrigation flow rate. The flow rate per row of drip irrigation tape is approximately 0.8 × (1 ÷ 0.3) × 200 m ≈ 533 L / h. Each irrigation zone has 165 rows of drip irrigation tape, and the total flow rate for each irrigation zone is approximately 165 × 533 L / h ≈ 88 m³ / h.

[0037] The pressure loss database stores the total head loss value H corresponding to each irrigation district i. i The system calculates local losses and elevation differences, and establishes a "rotational irrigation area - pressure demand" mapping relationship based on pre-calculated hydraulic results. This mapping relationship is then read by the controller during rotational irrigation area switching to generate the initial target pressure setpoint P for that rotational irrigation area. set,i .

[0038] The Hazen–Williams formula is used, with a Hazen–Williams roughness coefficient C of 140, and a preset end working pressure P. end 1.2 bar ≈ 12 m water column, safety margin M is 2 m, due to flat terrain, elevation loss ΔH i Neglecting other factors, the total head loss H1 of the farthest 1500m main pipeline, calculated using the formula, is approximately 18.6m water column; the total head loss H1 of the nearest 150m main pipeline is... 10 A water column of approximately 1.9 meters.

[0039] The setpoint P for the farthest target pressure set1 :P set1 ≈12+18.6+2=32.6m (approximately 3.3 bar); The nearest target pressure setting value P set10 :P set10 ≈12+1.9+2=15.9m (approximately 1.6 bar); Similarly, the head target pressure setpoint P for each irrigation district can be calculated. set,i .

[0040] During the system design phase, the controller is based on the head target pressure setpoint P. set,i The system calculates the initial pump frequency and gradually increases the voltage to allow the motor to start smoothly, preventing sudden pressure rises and water hammer. A head pressure sensor monitors the head pressure in real time, and the controller dynamically adjusts the pump speed based on the deviation between the set and actual values, stabilizing the pressure difference within ±0.1 bar. When switching irrigation zones, automatic pressure reduction and re-increase control quickly stabilizes the irrigation zone pressure within 5–10 seconds, preventing water hammer and flow fluctuations. When the pressure difference exceeds 0.3 bar, the frequency is automatically reduced and an alarm is triggered. By monitoring the operating frequency of the irrigation zones and changes in the main pipeline flow rate in real time, abnormalities in the drip irrigation system can be quickly identified.

[0041] This demonstration area is divided into 10 irrigation zones. Each irrigation zone is equipped with a soil moisture sensor. The soil moisture sensor measures the soil moisture content. When the soil moisture is lower than the set threshold, the sensor transmits a signal to the control system, and the system will automatically start irrigation.

[0042] The system is configured to start irrigation from the furthest irrigation zone 1 in this demonstration area. The method for a drip irrigation rotation zone pressure intelligent control system based on head loss mapping includes the following steps: S1: The controller reads the solenoid valve control signal of the zone valve, identifies the rotational irrigation zone 1 that needs to be irrigated, and proceeds to step S2; S2: The controller queries the pressure loss database for the total head loss value H1 corresponding to irrigation zone 1 based on the zone valve number, and proceeds to step S3; S3: The controller determines the preset end working pressure P. end The head pressure setpoint P for irrigation area 1 was calculated from the total head loss value H1. set,1 The controller generates a pressure regulation command and sends it to the pump station, proceeding to step S4; S4: The pump station receives the pressure regulation command from the controller and adjusts the pump output pressure through the frequency converter to make the head pressure value of the pump station approach the head target pressure set value P. set,1 Perform stable irrigation operations and proceed to step S5; S5: During irrigation, the head pressure sensor monitors the head pressure at the pump station outlet in real time and feeds back the head pressure signal to the controller, then proceeds to step S6; S6: The controller will synchronously collect the pump station's operating frequency N(t), main pipeline flow rate Q(t), and system stable operating parameters N in real time. stable,1 Q stable,1 The absolute differences ΔN and ΔQ and the deviation ΔN from the operating frequency threshold of the pumping station threshold , Main flow rate threshold deviation ΔQ threshold Compare and determine whether the system meets normal operating conditions; If ΔQ≤ΔQ threshold And ΔN≤ΔN threshold If the system meets the normal operating conditions, proceed to step S7. If ΔQ>ΔQ threshold , or ΔN>ΔN threshold If so, it is determined that the system has an abnormal operating condition, and the process proceeds to step S8; S7: The controller is in self-learning mode, corrects the total head loss value H1, and updates the corrected H1 to the pressure loss database; after the irrigation of irrigation zone 1 is completed, the irrigation zone is switched, the valve of the next zone is opened, the valve of irrigation zone 1 is closed, and the process returns to step S1. In self-learning mode, the system maintains the initial target pressure P. set,1 Under these conditions, when the actual operating flow rate Q(t) of the main pipeline is higher than the stable operating flow rate Qt... stable,1 When the actual total head loss of the system is less than the total H1 recorded in the pressure loss database, the total head loss value H1 is reduced; when the actual operating flow rate Q(t) of the main pipeline is lower than the flow rate Q during stable operation... stable,1 If the total head loss value H1 is increased, the corrected total head loss value H1 will maintain the target head pressure of the system. Pset,1 ; S8: The system transitions from normal operating conditions to abnormal operating conditions, enters abnormal protection mode, stops learning and correcting the total head loss value H1, alarms, and controls the cessation of irrigation.

[0043] Under normal operating conditions, the system automatically controls the irrigation of irrigation zones 1-10 in sequence. Through the technical solution of this invention, the pressure supply of irrigation zones at both the far and near ends is stable, and the pressure of the end dripper is maintained at 1.15-1.25 bar; the uniformity is improved by 10-18%, the system saves energy by 15-25%, and the system operates reliably, achieving stable pressure, improved uniformity, and energy saving and cost reduction.

[0044] The above description provides examples of the preferred embodiments of the present invention. Parts not detailed herein are common knowledge to those skilled in the art. The scope of protection of the present invention is determined by the claims. Any equivalent modifications based on the technical teachings of the present invention are also within the scope of protection of the present invention.

Claims

1. A smart pressure control system for drip irrigation districts based on head loss mapping, characterized in that: This includes pump stations, zone valves, controllers, head pressure sensors, and a pressure loss database; The pressure loss database stores the pipeline head loss value, local head loss value and elevation loss parameter corresponding to each irrigation zone, so that the controller can read the "irrigation zone - pressure demand" data when switching irrigation zones. The controller is used to identify the currently activated irrigation zone and query the corresponding total head loss value H from the "Irrigation Zone - Pressure Demand" data. i According to the preset end working pressure P end Generate and issue the head target pressure setpoint P set,i The adjustment command is sent to the pumping station; The zone valve is used to control the opening and closing status of each irrigation zone and to provide the address signal of the irrigation zone to the controller; The pumping station receives adjustment commands from the controller and, through a frequency converter, provides head pressure to the activated irrigation area, maintaining the head pressure at the target head pressure setpoint P. set,i Within the set range; The head pressure sensor is used to monitor the head pressure at the pump station outlet in real time and feed the head pressure signal back to the controller.

2. The control system according to claim 1, characterized in that: The total head loss value H i Including head loss value HW i and elevation loss value ΔH i ; The head loss value HW i This includes the head loss along the friction length (HFi) and the local head loss (HJ). i .

3. The control system according to claim 2, characterized in that: The pressure loss database calculates the head loss along the pipeline segment by segment based on the Hazen–Williams formula for each irrigation zone i, corresponding to the main and branch pipe sections. The calculation formula is: in: : Head loss along the pipe section, in meters of water column; L: The length of this pipe section, in meters; Q: The volumetric flow rate through this pipe section, in cubic meters per second; D: Pipe inner diameter, in meters; C: Hazen–Williams roughness coefficient, a dimensionless constant; The head loss value along the friction HF i The head loss along each pipeline (h) f The sum calculation, that is: Head loss value HW i for: HW i =HF i +HJ i Among them, HJ i HJ represents the local head loss value. i ≈ (10 ± 0.5)%HF i ; Elevation loss value ΔH i for: ΔH i =Hi end -Hi start Among them, Hi end It is the elevation of the endpoint, Hi start It is the elevation of the starting point; Total head loss value H i for: H i =HW i +ΔH i 。 4. The control system according to claim 3, characterized in that, The head target pressure set value P set,i for: P set,i =P end +H i +M Among them, P end To preset the terminal working pressure, H i Let M be the total head loss value of irrigation area i, and M be the safety margin.

5. A method for implementing the intelligent pressure control system for drip irrigation reel irrigation areas based on head loss mapping as described in claims 1-4, characterized in that, Includes the following steps: S1: The controller reads the solenoid valve control signal of the zone valve, identifies the irrigation zone i that needs to be irrigated, and proceeds to step S2; S2: The controller queries the pressure loss database for the total head loss value H corresponding to irrigation zone i based on the zone valve number. i Proceed to step S3; S3: The controller determines the preset end working pressure P. end Total head loss value H i The head target pressure setpoint P for irrigation area i in this cycle was calculated. set,i The controller generates a pressure regulation command and sends it to the pump station, proceeding to step S4; S4: The pump station receives the pressure regulation command from the controller and adjusts the pump output pressure through the frequency converter to make the head pressure value of the pump station approach the head target pressure set value P. set,i Perform stable irrigation operations and proceed to step S5; S5: During irrigation, the head pressure sensor monitors the head pressure at the pump station outlet in real time and feeds back the head pressure signal to the controller, then proceeds to step S6; S6: The controller will synchronously collect the pump station's operating frequency N(t), main pipeline flow rate Q(t), and system stable operating parameters N in real time. stable,i Q stable,i The absolute differences ΔN and ΔQ and the deviation ΔN from the operating frequency threshold of the pumping station threshold , Main flow rate threshold deviation ΔQ threshold Compare and determine whether the normal operating conditions are met; If ΔQ≤ΔQ threshold And ΔN≤ΔN threshold If the condition is met, proceed to step S7. If ΔQ>ΔQ threshold , or ΔN>ΔN threshold If so, it is determined that there is an abnormal working condition, and the process proceeds to step S8; S7: The controller is in self-learning mode, correcting the total head loss value H. i And the corrected H i Update to the pressure loss database; after irrigation of irrigation zone i is completed, switch irrigation zones, open the valve of the next zone, close the valve of irrigation zone i, and return to step S1; S8: Enter protection mode and stop monitoring the head loss value H along the friction path. i It learns and corrects, alarms, and controls to stop irrigation.

6. The control method based on claim 5, characterized in that, In step S7, when the system is in self-learning mode, the system maintains the target pressure P at the head. set,i Under these conditions, when the actual operating flow rate Q(t) of the main pipeline is higher than the stable operating flow rate Qt... stable,i At that time, the actual total head loss of the system is less than the total head loss value H recorded in the pressure loss database. i This reduces the total head loss value H. i When the actual operating flow rate Q(t) of the main pipeline is lower than the stable operating flow rate Qt... stable,i When this happens, the total head loss value H is increased. i .

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