An automatic flow rate adjustment method and system for a groundwater sampling apparatus

Abstract

The present application relates to the field of automatic control technology, in particular to an automatic flow rate adjusting method and system for groundwater sampling equipment, comprising the following steps: receiving a target water flow rate, collecting voltage information and current information of a submersible pump and determining an operating power, determining a current water flow rate according to a preset corresponding relationship between the operating power and the water flow rate, comparing the target water flow rate with the current water flow rate and determining a deviation direction, forming a pulse width modulation duty cycle adjustment amount to control a brushless motor, and re-collecting the voltage information and the current information to continue adjusting. The present application forms a current water flow rate feedback through the operating power, and adjusts the operating state of the brushless motor according to the comparison result of the target water flow rate and the current water flow rate, so that the flow rate determination and the submersible pump driving form a cyclic control relationship, the flow rate fluctuation caused by manual repeated adjustment is reduced, and the water flow rate in the groundwater well washing and sampling process is continuously adjusted according to the target water flow rate.

Description

Technical Field

[0001] This invention relates to the field of automatic control technology, and in particular to an automatic flow rate regulation method and system for groundwater sampling equipment. Background Technology

[0002] The field of automatic control technology mainly focuses on the correspondence between equipment operating status and control objectives. It involves first acquiring detection signals generated during equipment operation, then judging the detection results based on pre-set control conditions, and transmitting the resulting control commands to the corresponding actuators. This causes the equipment to change its operating status according to the control commands, and subsequent detection results can continue to serve as the basis for control judgments. Specifically, the automatic flow rate adjustment method and system for traditional groundwater sampling equipment refers to a control method that adjusts the operation of the submersible pump based on the water output status during well washing and groundwater sampling. Typically, a flow detector installed in the outlet pipeline acquires the flow signal and transmits it to the controller. The controller determines the adjustment command based on the relationship between the detected flow rate and the set flow rate, then controls the submersible pump operation via a motor drive circuit, and continues to make corresponding judgments and adjustments based on subsequently acquired flow signals.

[0003] In traditional deep groundwater well flushing and sampling operations, the flow rate of submersible pumps is mostly adjusted by operators based on the on-site water conditions. Flow detection and submersible pump drive control rely on repeated manual intervention, making it difficult to convert flow changes into continuous control data in a timely manner. Under low flow conditions, flow fluctuations are prone to occur due to mismatch in adjustment range. Deep monitoring wells are also limited by well diameter and head, and the control equipment and power supply conditions increase the burden of field deployment. Therefore, the existing control methods have problems such as insufficient continuity of flow regulation and high dependence on on-site operation when performing low-flow well flushing and sampling in small-diameter deep wells. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic flow rate adjustment method and system for groundwater sampling equipment. The method involves collecting voltage and current information from a submersible pump during operation to determine its operating power, and determining the current flow rate based on a preset correspondence between the operating power and the outflow rate. A target flow rate is then compared with the current flow rate. Based on the flow rate comparison result, the deviation direction and degree of the current flow rate from the target flow rate are determined. A pulse width modulation (PWM) duty cycle adjustment amount is calculated based on the deviation direction and degree, and this PWM duty cycle adjustment amount controls the brushless motor of the submersible pump. This allows the current flow rate to be re-determined as the brushless motor's operating state changes, and the adjustment continues based on the updated flow rate comparison result until the current flow rate matches the target flow rate.

[0005] To achieve the above objectives, the present invention provides an automatic flow rate adjustment method for a groundwater sampling device, comprising the following steps: Obtain the target outflow rate for groundwater well flushing or sampling operations, start the submersible pump, and collect the voltage and current information of the submersible pump during operation; The operating power is determined based on the voltage and current information of the submersible pump, and the current water flow rate is determined based on the preset correspondence between the operating power and the water flow rate. The target effluent flow rate is compared with the current effluent flow rate to form a flow rate comparison result. Based on the flow rate comparison result, the deviation direction and degree of the current effluent flow rate from the target effluent flow rate are determined, and the pulse width modulation duty cycle adjustment amount is calculated based on the deviation direction and the degree of deviation. The brushless motor of the submersible pump is controlled according to the pulse width modulation duty cycle adjustment amount. The voltage and current information of the submersible pump during operation are re-acquired, the operating power and the current water flow rate are re-determined, and the flow rate comparison result is updated. The pulse width modulation duty cycle adjustment amount is continued to be generated based on the updated flow rate comparison result, and the brushless motor is controlled until the flow rate comparison result shows that the deviation between the current water flow rate and the target water flow rate is within the preset deviation threshold range and the set conditions are maintained, and the current control state of the brushless motor is maintained.

[0006] Furthermore, the target outflow rate is a pre-determined flow rate set value based on the groundwater well flushing or sampling operation before starting the submersible pump, and the target outflow rate remains constant during one groundwater well flushing or sampling operation. After starting the submersible pump, voltage and current information are collected synchronously according to the sampling cycle. The voltage and current information obtained at the same sampling moment are used as a set of corresponding data, and the operating power is determined based on each set of corresponding data. When the brushless motor is controlled according to the pulse width modulation duty cycle adjustment and the voltage and current information are collected again, the sampling cycle remains unchanged, and the voltage and current information obtained at the same sampling moment are used as a set of corresponding data. The operating power determined each time corresponds to the voltage and current information synchronously obtained under the corresponding operating state of the submersible pump.

[0007] Furthermore, when determining the operating power based on each set of corresponding data, the voltage and current information obtained at the same sampling time are processed accordingly to obtain the instantaneous power corresponding to the sampling time; multiple instantaneous powers are obtained in chronological order of multiple consecutive sampling times, and the multiple instantaneous powers are averaged to obtain the operating power used to determine the current outflow rate. After re-collecting the voltage and current information, the same sampling time correspondence method and averaging method are used to re-determine the operating power, so that the operating power obtained each time has the same data processing caliber.

[0008] Furthermore, the preset correspondence is the pre-acquired and stored correspondence data between the operating power and the outflow rate. When determining the current outflow rate, the currently determined operating power is compared with multiple power data in the preset correspondence; when a match is found between the power data corresponding to the operating power, the flow rate data corresponding to the power data is determined as the current outflow rate; when no match can be found between the power data corresponding to the operating power, two power data located on both sides of the operating power and adjacent to the operating power are determined from the preset correspondence, and the current outflow rate is determined based on the flow rate data corresponding to the two power data.

[0009] Furthermore, when comparing the target effluent flow rate with the current effluent flow rate, a flow rate difference between the target effluent flow rate and the current effluent flow rate is determined, and a flow rate comparison result is formed based on the flow rate difference. When the current effluent flow rate is lower than the target effluent flow rate, the deviation direction is determined as the flow rate increasing direction; when the current effluent flow rate is higher than the target effluent flow rate, the deviation direction is determined as the flow rate decreasing direction; when the current effluent flow rate is the same as the target effluent flow rate, the flow rate comparison result is determined as a flow rate consistency state, and the formation of a new pulse width modulation duty cycle adjustment is stopped.

[0010] Furthermore, when adjusting the pulse width modulation duty cycle based on the deviation direction, the single adjustment amplitude of the duty cycle is determined according to the magnitude of the flow difference. Multiple flow difference intervals are pre-set, and corresponding duty cycle adjustment amplitudes are set for each interval. After determining the flow difference interval to which the flow difference belongs, the corresponding duty cycle adjustment amplitude is used as the single adjustment amplitude of the duty cycle. When the deviation direction is the direction of increasing flow, the pulse width modulation duty cycle is increased according to the single adjustment amplitude; when the deviation direction is the direction of decreasing flow, the pulse width modulation duty cycle is decreased according to the single adjustment amplitude, and the amplitude of this increase or decrease is determined as the pulse width modulation duty cycle adjustment amount.

[0011] Furthermore, when controlling the brushless motor according to the pulse width modulation duty cycle adjustment amount, a pulse width modulation drive signal is generated to control the drive circuit, which drives the brushless motor. The duty cycle before adjustment is used as the starting duty cycle for this adjustment. The adjustment direction of the pulse width modulation duty cycle adjustment amount corresponding to the starting duty cycle is determined according to the deviation direction, and the starting duty cycle is adjusted according to the pulse width modulation duty cycle adjustment amount to obtain the adjusted duty cycle corresponding to this control. The adjusted duty cycle is compared with a preset upper limit and a preset lower limit. When the adjusted duty cycle is between the preset upper limit and the preset lower limit, the pulse width modulation drive signal is output according to the adjusted duty cycle. When the adjusted duty cycle exceeds the preset upper limit, the preset upper limit is used as the duty cycle of the pulse width modulation drive signal. When the adjusted duty cycle is lower than the preset lower limit, the preset lower limit is used as the duty cycle of the pulse width modulation drive signal, and the brushless motor is controlled according to the limited pulse width modulation drive signal.

[0012] Furthermore, after controlling the brushless motor once according to the pulse width modulation duty cycle adjustment, the brushless motor remains in the adjusted operating state until the next pulse width modulation duty cycle adjustment is formed. In this adjusted operating state, the voltage and current information are re-acquired, and the operating power is re-determined based on the re-acquired voltage and current information. The current outflow rate is also re-determined according to the preset correspondence. The re-determined current outflow rate is compared with the target outflow rate. After obtaining the updated flow rate comparison result, the deviation direction is determined based on the updated flow rate comparison result, and the next pulse width modulation duty cycle adjustment is formed. This ensures that flow rate re-determination and flow rate comparison are sequentially completed between two adjacent controls of the brushless motor.

[0013] Furthermore, when forming the pulse width modulation duty cycle adjustment amount based on the updated flow comparison result, the newly determined deviation direction is compared with the deviation direction used when controlling the brushless motor last time. When the deviation directions determined in two consecutive tests are the same, the brushless motor is controlled in the same direction according to the pulse width modulation duty cycle adjustment amount formed this time; when the deviation directions determined in two consecutive tests are opposite, the adjustment amplitude level to which the adjustment amplitude used when controlling the brushless motor last time belongs is determined, the adjustment amplitude of the pulse width modulation duty cycle adjustment amount formed this time is switched to the adjustment amplitude corresponding to the next lower level adjacent to the adjustment amplitude level, and the brushless motor is controlled according to the adjusted pulse width modulation duty cycle adjustment amount; when the updated flow comparison result shows that the deviation between the current effluent flow rate and the target effluent flow rate is within the preset deviation threshold range and the set conditions are maintained, the current control state of the brushless motor is maintained, and no new pulse width modulation duty cycle adjustment amount is formed.

[0014] The present invention also provides an automatic flow rate regulation system for a groundwater sampling device, used to execute the above-mentioned automatic flow rate regulation method, including a handheld terminal, a control box and a submersible pump, wherein the submersible pump is equipped with a brushless motor, and the control box is equipped with a wireless communication module, a control module, a speed regulation module and a drive module.

[0015] The wireless communication module receives the target water flow rate input by the handheld terminal and sends it to the control module.

[0016] The control module collects the voltage and current information of the submersible pump, determines the operating power, and determines the current water flow rate based on the preset correspondence between the operating power and the water flow rate. It compares the target water flow rate with the current water flow rate to form a flow rate comparison result, determines the deviation direction based on the flow rate comparison result, and forms a pulse width modulation duty cycle adjustment amount based on the deviation direction.

[0017] The speed control module controls the drive module to drive the brushless motor according to the pulse width modulation duty cycle adjustment.

[0018] After the brushless motor's operating state changes, the control module re-collects the voltage and current information, updates the operating power, the current outflow rate, and the flow rate comparison result, and generates a new pulse width modulation duty cycle adjustment amount based on the updated flow rate comparison result.

[0019] Compared with the prior art, the advantages and positive effects of the present invention are as follows: In this invention, the operating power is determined by collecting voltage and current information during submersible pump operation. The current outlet flow rate is then determined based on a preset correspondence between the operating power and the outlet flow rate. This allows the submersible pump's operating electrical parameters to serve as feedback for flow rate adjustment, reducing reliance on independent flow detection and manual observation. The deviation direction is determined by comparing the target outlet flow rate with the current outlet flow rate, and a pulse width modulation duty cycle adjustment is used to control the brushless motor, enabling the submersible pump's outlet state to adjust according to flow deviations. After the brushless motor's operating state changes, voltage and current information are collected again, and the current outlet flow rate and flow comparison result are determined again. This creates continuous feedback between the previous and subsequent adjustment processes, reducing flow fluctuations caused by repeated manual adjustments. This allows the outlet flow rate during groundwater well washing and sampling to gradually approach the target outlet flow rate, maintaining a correspondence between subsequent adjustment criteria and the actual operating state of the submersible pump. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the overall process for automatic flow regulation of groundwater sampling equipment; Figure 2 A schematic diagram showing the relationship between operating power and outflow rate, and the current outflow rate; Figure 3 A schematic diagram illustrating pulse width modulation duty cycle adjustment and duty cycle boundary limitation; Figure 4 A diagram illustrating the flow feedback update and adjustment level switching; Figure 5 This is a schematic diagram of the automatic flow rate regulation system for a groundwater sampling device. Detailed Implementation

[0022] To make the technical solution and working process of the present invention clearer, the specific embodiments of the present invention will be further described below with reference to the accompanying drawings. The groundwater well flushing or sampling operation of the present invention refers to the process of using a submersible pump to pump water from a groundwater monitoring well or a water intake location corresponding to groundwater collection, and performing well flushing or sampling according to a predetermined target outflow rate. The target outflow rate is a flow rate set value determined before the start of a groundwater well flushing or sampling operation; voltage and current information respectively characterize the voltage and current states corresponding to the power supply state during the operation of the submersible pump; the operating power is determined by the voltage and current information obtained at the same sampling moment; the current outflow rate is the flow rate result obtained based on the operating power and a pre-established correspondence between the operating power and the outflow rate.

[0023] The flow comparison result indicates the comparison status between the current effluent flow rate and the target effluent flow rate. The deviation direction indicates whether the current effluent flow rate should be adjusted in the direction of increasing or decreasing flow rate relative to the target effluent flow rate. The pulse width modulation duty cycle adjustment amount indicates the magnitude of the duty cycle adjustment required relative to the current pulse width modulation duty cycle. The pulse width modulation drive signal is used to control the operation of the brushless motor. The adjusted duty cycle is the duty cycle obtained after adjusting the initial duty cycle according to the deviation direction and the pulse width modulation duty cycle adjustment amount.

[0024] The preset upper and lower duty cycle limits define the range of duty cycles that the pulse width modulation drive signal can use. Their specific values ​​are determined based on the permissible drive range of the submersible pump and brushless motor. The sampling period defines the interval between the acquisition of two consecutive sets of voltage and current information, maintaining consistency throughout a single groundwater well flushing or sampling operation. The sampling period should be sufficient to continuously acquire voltage and current information at multiple sampling times after a duty cycle adjustment, enabling the re-determination of operating power and current outflow rate.

[0025] Example 1 Please see Figure 1-4 This embodiment provides an automatic flow rate regulation method for a groundwater sampling device. The automatic flow rate regulation method uses the target outflow rate as the regulation benchmark and the voltage and current information of the submersible pump during operation as the operating status input. It obtains the current outflow rate through a preset correspondence between operating power and outflow rate, and then generates a pulse width modulation duty cycle adjustment amount based on the comparison between the current outflow rate and the target outflow rate. This adjustment amount is then used to control the brushless motor. After one regulation is completed, the voltage and current information are re-acquired, and the newly determined current outflow rate is used in the next flow rate comparison, thus forming a continuous flow feedback regulation process.

[0026] S1: Obtain the target outflow rate for groundwater well washing or sampling operations, start the submersible pump, and collect voltage and current information during submersible pump operation.

[0027] Before groundwater well flushing or sampling operations begin, the target effluent flow rate for this operation is determined. The target effluent flow rate remains constant throughout a single groundwater well flushing or sampling operation; therefore, all subsequent flow rate comparisons use the same target effluent flow rate as the comparison benchmark. When employing the automatic flow regulation system method described later, the target effluent flow rate is input via a handheld terminal and transmitted to the control module via a wireless communication module. The control module receives and saves the target effluent flow rate for later retrieval when determining flow rate comparison results.

[0028] Once the target outflow rate is determined, the submersible pump is started, putting it into pumping operation. After the submersible pump starts, voltage and current information are collected according to the sampling period. Each sampling moment corresponds to one voltage and one current information, making the two pieces of information obtained at the same sampling moment a set of corresponding data. Thus, the voltage and current information in a set of corresponding data correspond to the power supply status of the submersible pump at the same operating state and the same sampling moment, avoiding the mixing of voltage and current status obtained at different sampling moments.

[0029] When multiple sets of corresponding data are continuously acquired during the control process, the data are arranged in chronological order of sampling time. For re-acquisition processes after the same adjustment, the same sampling period and synchronous acquisition method are used, ensuring that the data formation method remains unchanged despite a single adjustment of the brushless motor. Therefore, the corresponding data obtained before and after adjustment have a consistent acquisition scope, and the subsequently determined operating power can correspond to the actual operating state of the submersible pump after each adjustment.

[0030] In practice, it is only necessary to ensure that the sampling interval for re-determining the operating power includes multiple consecutive sampling moments, and that voltage and current information are synchronously generated into corresponding data at the same sampling moment. After the previous round of adjustment is completed, the sampling period remains unchanged so that the same data acquisition method is used between adjacent control cycles.

[0031] S2 determines the operating power based on the voltage and current information of the submersible pump, and determines the current water flow rate based on the preset correspondence between the operating power and the water flow rate.

[0032] For each set of corresponding data generated by S1, the voltage and current information obtained at the same sampling time are processed to obtain the instantaneous power corresponding to that sampling time. The instantaneous power is determined only using the voltage and current information from the same set of corresponding data, without using voltage or current information from other sampling times. Multiple instantaneous powers can be obtained sequentially according to the order of multiple consecutive sampling times.

[0033] After obtaining the instantaneous power, multiple instantaneous power values ​​belonging to the same operating state sampling interval are averaged, and the average result is used as the operating power for this flow determination. The averaging process is performed on multiple consecutively sampled instantaneous power values ​​to ensure that voltage or current changes at a single sampling moment are not used as the sole basis for flow determination. When re-collecting voltage and current information after a change in the brushless motor's operating state, the same sampling time correspondence and averaging method are used to re-determine the operating power, ensuring consistency in the data processing for each subsequent determination of operating power.

[0034] The preset correspondence consists of pre-acquired and stored data linking operating power and effluent flow rate. This correspondence is established under preset calibration conditions, including preset head ranges or water level variation ranges. When establishing the preset correspondence, within the working domain corresponding to the calibration conditions, each operating power data point is monotonically correlated with one effluent flow rate data point. Multiple sets of operating power and effluent flow rate data constitute a queryable set of corresponding data. The effluent flow rate data is acquired through flow measurement equipment and should characterize the actual effluent flow rate matching the corresponding operating power state at the time the preset correspondence is established. After establishment, the preset correspondence is stored in the local storage location used for the flow rate determination process and is retrieved each time a new operating power is obtained.

[0035] When determining the current outflow rate, the determined operating power is compared with multiple power data in a preset correspondence. If a power data matching the current operating power exists in the preset correspondence, the flow rate corresponding to that power data is read and determined as the current outflow rate. This forms a continuous data processing chain from the collected voltage and current information, through instantaneous power and operating power, to the current outflow rate.

[0036] When no power data that can be directly matched with the current operating power cannot be found in the preset correspondence, two power data points located on either side of the current operating power and adjacent to it are determined according to the magnitude relationship of the power data in the preset correspondence. Then, the flow data corresponding to the two power data points are read, and the current effluent flow rate is determined based on the two flow data points. For the specific flow value form used between the two adjacent power data points, it is only required that the current effluent flow rate is jointly determined by the power data adjacent to the operating power on both sides and their corresponding flow data.

[0037] Since voltage and current information are re-acquired each time the control state of the brushless motor changes, the corresponding operating power is also re-determined based on the re-acquired data. The re-determined operating power is then queried again using the same preset correspondence or determined from adjacent data to obtain a new current outlet flow rate corresponding to the adjusted operating state of the submersible pump.

[0038] S3. Compare the target effluent flow rate with the current effluent flow rate to form a flow rate comparison result. Based on the flow rate comparison result, determine the deviation direction and degree of the target effluent flow rate corresponding to the current effluent flow rate, and calculate the pulse width modulation duty cycle adjustment amount based on the deviation direction and degree of deviation.

[0039] After obtaining the current effluent flow rate, the target effluent flow rate, which is predetermined and remains unchanged in S1, is read. The current effluent flow rate is compared with the target effluent flow rate, and the flow difference between the two is determined. The flow difference is used to characterize the degree of difference between the current effluent flow rate and the target effluent flow rate. The flow comparison result reflects both the magnitude relationship between the two and whether they have reached a consistent state.

[0040] When the current effluent flow rate is lower than the target effluent flow rate, the deviation direction is determined as the flow rate increase direction; when the current effluent flow rate is higher than the target effluent flow rate, the deviation direction is determined as the flow rate decrease direction; when the current effluent flow rate is the same as the target effluent flow rate, the flow rate comparison result is determined as a flow rate consistency state. Once the deviation direction is formed, it serves as the direction input for subsequent pulse width modulation duty cycle adjustment, and the flow rate difference serves as the basis for determining the magnitude of this duty cycle adjustment.

[0041] In order to enable different flow difference values ​​to correspond to different duty cycle adjustment ranges, multiple flow difference ranges are preset, and duty cycle adjustment ranges corresponding to each flow difference range are set. The settings should be such that each flow difference value that needs to be adjusted can determine the flow difference range to which it belongs, and a corresponding duty cycle adjustment range can be obtained from the flow difference range.

[0042] After determining the flow difference range to which the current flow difference belongs, the duty cycle adjustment amplitude corresponding to this flow difference range is read and used as the single duty cycle adjustment amplitude for this operation. When the deviation direction is the direction of increasing flow, the single duty cycle adjustment amplitude is used to generate the adjustment amount for increasing the pulse width modulation duty cycle; when the deviation direction is the direction of decreasing flow, the single duty cycle adjustment amplitude is used to generate the adjustment amount for decreasing the pulse width modulation duty cycle. The duty cycle change amplitude determined in this operation is used as the pulse width modulation duty cycle adjustment amount and is transmitted to S4 along with the deviation direction.

[0043] Multiple duty cycle adjustment amplitudes can also be configured with corresponding adjustment amplitude levels according to their magnitude, so that each duty cycle adjustment amplitude has an adjustment amplitude level that can be identified in order of magnitude. The adjustment amplitude level is used to determine the adjustment amplitude of the next level when two adjacent deviation directions reverse. The specific number of levels is determined by the number of duty cycle adjustment amplitudes that have been set, without adding any control parameters independent of the duty cycle adjustment amplitude.

[0044] S4. Control the brushless motor of the submersible pump according to the pulse width modulation duty cycle adjustment amount, re-collect the voltage and current information of the submersible pump during operation, redetermine the operating power and current water flow rate, and update the flow comparison result. Based on the updated flow comparison result, continue to generate the pulse width modulation duty cycle adjustment amount and control the brushless motor until the flow comparison result shows that the deviation between the current water flow rate and the target water flow rate is within the preset deviation threshold range and the set conditions are maintained.

[0045] When performing a duty cycle adjustment, a pulse width modulation (PWM) drive signal for controlling the brushless motor is first generated, and the duty cycle used by the PWM drive signal before the start of this adjustment is taken as the initial duty cycle. The deviation direction and PWM duty cycle adjustment amount generated in S3 are read. Based on the deviation direction, the adjustment direction relative to the initial duty cycle is determined. Then, the initial duty cycle is adjusted once according to the PWM duty cycle adjustment amount to obtain the adjusted duty cycle corresponding to this control.

[0046] After obtaining the adjusted duty cycle, it is not directly used as the final driving duty cycle. Instead, it is first compared with the preset upper and lower duty cycle limits. When the adjusted duty cycle is between the preset upper and lower limits, the pulse width modulation (PWM) driving signal is output according to the adjusted duty cycle. When the adjusted duty cycle exceeds the preset upper limit, the preset upper limit is used as the duty cycle of the PWM driving signal; when the adjusted duty cycle is lower than the preset lower limit, the preset lower limit is used as the duty cycle of the PWM driving signal. Thus, the PWM duty cycle adjustment amount first forms candidate adjusted duty cycles, and then, after being bounded by the preset upper and lower limits, forms the actual output duty cycle.

[0047] After controlling the brushless motor according to the boundary-defined pulse width modulation drive signal, the brushless motor is kept in the operating state after this adjustment. Before the next pulse width modulation duty cycle adjustment is formed, the duty cycle is not changed continuously immediately. Instead, after a preset stabilization delay in the operating state, the acquisition of voltage and current information is re-executed, so that the next flow judgment is based on the stable operating state achieved after this adjustment.

[0048] When the brushless motor is in the adjusted operating state, voltage and current information are re-acquired according to the same sampling period as in S1, and the operating power is re-determined according to the same processing method as in S2. After obtaining the operating power again, the current outflow rate is re-determined based on the same preset correspondence established under the preset calibration conditions. Thus, the change in the brushless motor's operating state caused by this duty cycle adjustment is reflected in the new operating power through the re-acquired voltage and current information, and further reflected in the new current outflow rate.

[0049] The newly determined current effluent flow rate is compared again with the target effluent flow rate, the flow rate comparison result is updated, and the direction of deviation is redefined. Since the target effluent flow rate remains unchanged during a single operation, each update uses the same target effluent flow rate as the comparison benchmark, while the current effluent flow rate is redefined based on the operating status after the previous duty cycle control.

[0050] When two consecutive deviation directions are the same, it indicates that the current outflow rates in both instances are located on the same side of the target outflow rate. At this point, the duty cycle adjustment amplitude is re-acquired according to the flow difference interval to which the current flow difference belongs, forming the current pulse width modulation duty cycle adjustment amount. The brushless motor continues to be controlled along the same deviation direction. After the control process is completed, the voltage and current information are re-acquired.

[0051] When two consecutive deviation directions are determined to be opposite, first determine the adjustment amplitude level corresponding to the adjustment amplitude used in the previous control of the brushless motor, and then switch the adjustment amplitude of the pulse width modulation duty cycle adjustment amount formed this time to the adjustment amplitude corresponding to the next lower level adjacent to that adjustment amplitude level; if the adjustment amplitude used last time is already at the lowest level, then keep the adjustment amplitude corresponding to the lowest level unchanged. After completing the adjustment amplitude level switching or maintenance, determine the current adjustment direction based on the deviation direction, and control the brushless motor according to the adjusted pulse width modulation duty cycle adjustment amount. The level switching is performed on the duty cycle adjustment amplitude and does not change the target effluent flow rate, sampling period, preset correspondence, or the method of forming the flow comparison result.

[0052] After completing the above control, the voltage and current information are collected again along the same path, the operating power and current outflow rate are re-determined, and the flow comparison result is updated again. Thus, between two adjacent brushless motor control operations, a complete flow re-determination process and a flow comparison process are set up. The output state of the previous control forms the basis for the operation of the next data acquisition, and the flow comparison result formed in the next operation determines whether to continue to form the pulse width modulation duty cycle adjustment.

[0053] When the updated flow comparison results indicate that the deviation between the current effluent flow rate and the target effluent flow rate is within the preset deviation threshold range and the set conditions are maintained, no new pulse width modulation duty cycle adjustment is generated, and the current control state of the brushless motor is maintained. At this time, the current effluent flow rate is determined by the voltage and current information re-acquired under the current operating state, rather than directly using the historical flow state before adjustment. Therefore, the termination condition of this round of closed-loop adjustment can be judged by whether the flow comparison result enters the flow consistency state.

[0054] During a groundwater well flushing or sampling operation, if it is necessary to confirm the current operating status later, voltage and current information can continue to be obtained according to the same sampling cycle, and the current effluent flow rate can be determined using the same preset correspondence mentioned above. As long as the flow rate comparison result still indicates that the deviation between the current effluent flow rate and the target effluent flow rate is within the preset deviation threshold range and the set conditions are maintained, that is, the current control state of the brushless motor is maintained; when the re-determined flow rate comparison result is no longer in a flow rate consistency state, the comparison, adjustment quantity formation, and control path of S3 and S4 are re-processed, so that the judgment object, control object, and feedback object of the method always remain in correspondence.

[0055] Example 2 Please see Figure 5 This embodiment provides an automatic flow rate regulation system for a groundwater sampling device. The automatic flow rate regulation system is used to execute the automatic flow rate regulation method of Embodiment 1. The automatic flow rate regulation system includes a handheld terminal, a control box, and a submersible pump. The submersible pump is equipped with a brushless motor, and the control box includes a wireless communication module, a control module, a speed regulation module, and a drive module. The various components of the system form a closed loop according to the sequence of target effluent flow rate input, operating status acquisition, flow rate determination, comparison and judgment, duty cycle adjustment, drive execution, and re-acquisition. This does not change the technical meaning of the target effluent flow rate, operating power, current effluent flow rate, flow rate comparison result, deviation direction, and pulse width modulation duty cycle adjustment amount in Embodiment 1.

[0056] The handheld terminal receives the target effluent flow rate used in groundwater well flushing or sampling operations and transmits it to the wireless communication module. The handheld terminal serves as the input for the target effluent flow rate in this system and does not participate in determining the operating power or current effluent flow rate. After receiving the target effluent flow rate from the handheld terminal, the wireless communication module transmits it to the control module, enabling the control module to obtain a flow rate comparison benchmark for this operation.

[0057] After receiving the target effluent flow rate, the control module collects the submersible pump's voltage and current information during startup. The control module establishes a correspondence between the voltage and current information at the same sampling time and determines the operating power based on the corresponding data from multiple consecutive sampling times. The control module reads the preset correspondence between operating power and effluent flow rate, and determines the current effluent flow rate based on the matching result of the operating power in the preset correspondence or adjacent power data.

[0058] After obtaining the current effluent flow rate, the control module compares it with the target effluent flow rate to form a flow comparison result, and determines the direction of deviation based on the result. The control module also obtains the corresponding duty cycle adjustment range based on the flow difference interval to which the flow difference belongs, thus forming the pulse width modulation duty cycle adjustment amount. Therefore, the control information output by the control module to the speed control module includes at least information that can determine the direction and magnitude of the current duty cycle change.

[0059] The speed control module receives the pulse width modulation (PWM) duty cycle adjustment amount and controls the drive module accordingly. When the speed control module performs duty cycle adjustment, it uses the duty cycle before the adjustment as the starting duty cycle, obtains the adjusted duty cycle based on the deviation direction and the PWM duty cycle adjustment amount, and limits the adjusted duty cycle according to preset upper and lower duty cycle limits. The duty cycle after boundary limitation is used as the basis for controlling the duty cycle of the drive module.

[0060] The drive module receives the control result from the speed control module and drives the brushless motor according to the corresponding pulse width modulation drive signal. After responding to the pulse width modulation drive signal, the brushless motor changes its operating state, and the submersible pump's operating state changes accordingly. During this process, the drive module acts as the actuator between the speed control module and the brushless motor, without altering the deviation direction or pulse width modulation duty cycle adjustment determined by the control module.

[0061] After the brushless motor's operating state changes, the control module re-collects the submersible pump's voltage and current information, and updates the operating power, current outlet flow rate, and flow comparison result using the same acquisition and processing method as the previous round. If the updated flow comparison result still does not indicate that the current outlet flow rate matches the target outlet flow rate, the control module generates a new pulse width modulation duty cycle adjustment and sends it again to the speed control module; the speed control module then controls the drive module to continue driving the brushless motor. When the updated flow comparison result indicates that the current outlet flow rate matches the target outlet flow rate, the control module stops generating new pulse width modulation duty cycle adjustments, and the brushless motor maintains its current control state.

[0062] If two consecutive deviations occur in opposite directions, the adjustment level corresponding to the previous adjustment amplitude used to control the brushless motor is determined, and the adjustment amplitude of the current pulse width modulation duty cycle is switched to the next lower level adjacent to the previous adjustment amplitude level. If the previous adjustment amplitude was already at the lowest level, the adjustment amplitude corresponding to the lowest level remains unchanged. After completing the adjustment amplitude switching or maintenance, the adjusted pulse width modulation duty cycle is used to generate a pulse width modulation drive signal to drive the brushless motor, and then the process of acquiring voltage and current information is restarted.

[0063] Thus, the handheld terminal and the wireless communication module form the input and transmission path of the target outflow rate, the control module forms the data processing path from voltage and current information to operating power, current outflow rate, flow comparison result, deviation direction, and pulse width modulation duty cycle adjustment amount, the speed control module and the drive module form the control execution path from pulse width modulation duty cycle adjustment amount to brushless motor, and the voltage and current information re-acquired after the submersible pump's operating state changes forms the feedback input, enabling each component of the system to operate in closed loop according to the method of Embodiment 1.

[0064] The above embodiments, including the steps, data correspondence, flow comparison, duty cycle adjustment, module division of labor, and information transmission relationships, illustrate the specific execution process of the technical solution described in this invention in groundwater well washing or sampling equipment. The specific quantities or values ​​of the sampling period, flow difference range, duty cycle adjustment amplitude, adjustment amplitude level, preset upper duty cycle limit, and preset lower duty cycle limit can be determined within the scope of the technical solution described in this invention based on the actual operating range of the submersible pump and brushless motor. Any equivalent adjustments to the execution subjects of the steps, the equivalent inheritance relationships between modules, the equivalent naming methods of data, and the equivalent adjustments to the control process do not alter the technical closed loop formed by the determination of operating power, current effluent flow rate, flow comparison, duty cycle adjustment, and feedback updates in this invention, and should fall under the protection of this patent.

Claims

1. An automatic flow rate adjustment method for a groundwater sampling device, characterized in that, Includes the following steps: Obtain the target outflow rate for groundwater well flushing or sampling operations, start the submersible pump, and collect the voltage and current information of the submersible pump during operation; The operating power is determined based on the voltage and current information of the submersible pump, and the current water flow rate is determined based on the preset correspondence between the operating power and the water flow rate. The target effluent flow rate is compared with the current effluent flow rate to form a flow rate comparison result. Based on the flow rate comparison result, the deviation direction and degree of the current effluent flow rate from the target effluent flow rate are determined, and the pulse width modulation duty cycle adjustment amount is calculated based on the deviation direction and the degree of deviation. The brushless motor of the submersible pump is controlled according to the pulse width modulation duty cycle adjustment amount. The voltage and current information of the submersible pump during operation are re-acquired, the operating power and the current water flow rate are re-determined, and the flow rate comparison result is updated. The pulse width modulation duty cycle adjustment amount is continued to be generated based on the updated flow rate comparison result, and the brushless motor is controlled until the flow rate comparison result shows that the deviation between the current water flow rate and the target water flow rate is within the preset deviation threshold range and the set conditions are maintained, and the current control state of the brushless motor is maintained.

2. The automatic flow rate adjustment method for groundwater sampling equipment according to claim 1, characterized in that, The target outflow rate is a predetermined flow rate set value based on the groundwater well flushing or sampling operation before starting the submersible pump, and the target outflow rate remains unchanged during one groundwater well flushing or sampling operation. After the submersible pump is started, the voltage information and the current information are collected synchronously according to the sampling period. The voltage information and current information obtained at the same sampling time are taken as a set of corresponding data, and the operating power is determined according to each set of corresponding data. When the brushless motor is controlled according to the pulse width modulation duty cycle adjustment amount and the voltage and current information are collected again, the sampling period remains unchanged, and the voltage and current information obtained at the same sampling time are used as a set of corresponding data. The operating power determined each time is corresponding to the voltage and current information obtained synchronously under the corresponding operating state of the submersible pump.

3. The automatic flow rate adjustment method for groundwater sampling equipment according to claim 2, characterized in that, When determining the operating power based on the corresponding data for each group, the voltage information and current information obtained at the same sampling time are processed accordingly to obtain the instantaneous power corresponding to the sampling time; Multiple instantaneous powers are acquired in sequence from multiple consecutive sampling times, and the multiple instantaneous powers are averaged to obtain the operating power used to determine the current outflow rate. After re-acquiring the voltage and current information, the operating power is re-determined using the same sampling time correspondence method and averaging processing method, so that the operating power obtained each time has the same data processing caliber.

4. The automatic flow rate adjustment method for the groundwater sampling equipment according to claim 3, characterized in that, The preset correspondence is the pre-acquired and stored data relating the operating power to the outflow rate; When determining the current outflow rate, the determined operating power is compared with multiple power data in the preset correspondence relationship. When the power data corresponding to the operating power is matched, the flow rate data corresponding to the power data is determined as the current outflow rate. When power data corresponding to the operating power cannot be matched, two power data located on both sides of the operating power and adjacent to the operating power are determined from the preset correspondence, and the current outflow rate is determined based on the flow data corresponding to the two power data.

5. The automatic flow rate adjustment method for the groundwater sampling equipment according to claim 4, characterized in that, When comparing the target effluent flow rate with the current effluent flow rate, the flow rate difference between the target effluent flow rate and the current effluent flow rate is determined, and the flow rate comparison result is formed based on the flow rate difference. When the current outflow rate is lower than the target outflow rate, the deviation direction is determined as the direction of flow increase; When the current outflow rate is higher than the target outflow rate, the deviation direction is determined as the direction of flow rate reduction; When the current outflow rate is consistent with the target outflow rate, the flow rate comparison result is determined to be in a consistent flow rate state, and the generation of a new pulse width modulation duty cycle adjustment amount is stopped.

6. The automatic flow rate adjustment method for the groundwater sampling equipment according to claim 5, characterized in that, When the pulse width modulation duty cycle adjustment amount is formed according to the deviation direction, the single adjustment amplitude of the duty cycle is determined according to the magnitude of the flow difference. Multiple flow difference intervals are preset, and duty cycle adjustment ranges corresponding to the flow difference intervals are set respectively. After determining the flow difference interval to which the flow difference belongs, the corresponding duty cycle adjustment range is used as the single duty cycle adjustment range. When the deviation direction is the direction of the increased flow rate, the pulse width modulation duty cycle is increased by the single adjustment amplitude according to the duty cycle; When the deviation direction is the direction of decreasing flow, the pulse width modulation duty cycle is reduced according to the single adjustment amplitude of the duty cycle, and the amplitude of the increase or decrease of the duty cycle is determined as the adjustment amount of the pulse width modulation duty cycle.

7. The automatic flow rate adjustment method for the groundwater sampling equipment according to claim 1, characterized in that, When controlling the brushless motor according to the pulse width modulation duty cycle adjustment amount, a pulse width modulation drive signal is generated to control the drive circuit, and the brushless motor is driven through the drive circuit, with the duty cycle before adjustment being used as the starting duty cycle for this adjustment. Based on the deviation direction, determine the adjustment direction of the pulse width modulation duty cycle adjustment amount corresponding to the initial duty cycle, and adjust the initial duty cycle according to the pulse width modulation duty cycle adjustment amount to obtain the adjusted duty cycle corresponding to this control. The adjusted duty cycle is compared with the preset upper limit and the preset lower limit of the duty cycle. When the adjusted duty cycle is between the preset upper limit and the preset lower limit of the duty cycle, the pulse width modulation drive signal is output according to the adjusted duty cycle. When the adjusted duty cycle exceeds the preset upper limit of the duty cycle, the preset upper limit of the duty cycle is used as the duty cycle of the pulse width modulation drive signal. When the adjusted duty cycle is lower than the preset lower limit of the duty cycle, the preset lower limit of the duty cycle is used as the duty cycle of the pulse width modulation drive signal, and the brushless motor is controlled according to the limited pulse width modulation drive signal.

8. The automatic flow rate adjustment method for the groundwater sampling equipment according to claim 7, characterized in that, After controlling the brushless motor once according to the pulse width modulation duty cycle adjustment amount, the brushless motor is kept in the operating state after the current adjustment until the next pulse width modulation duty cycle adjustment amount is formed. Under the adjusted operating conditions, the voltage and current information are re-acquired, the operating power is re-determined based on the re-acquired voltage and current information, and the current outflow rate is re-determined based on the preset correspondence. The current outflow rate is redefined and compared with the target outflow rate. After obtaining the updated flow rate comparison result, the deviation direction is determined based on the updated flow rate comparison result, and the next pulse width modulation duty cycle adjustment amount is formed. This allows the flow rate to be redefined and compared sequentially between two adjacent control operations on the brushless motor.

9. The automatic flow rate adjustment method for the groundwater sampling equipment according to claim 8, characterized in that, When continuing to form the pulse width modulation duty cycle adjustment amount based on the updated flow comparison result, the newly determined deviation direction is compared with the deviation direction used when controlling the brushless motor last time; When the deviation directions determined in two consecutive steps are the same, the brushless motor continues to be controlled in the same direction according to the pulse width modulation duty cycle adjustment amount formed in this step. When the deviation directions determined in two consecutive steps are opposite, the adjustment amplitude level to which the adjustment amplitude used when controlling the brushless motor last time is determined, the adjustment amplitude of the pulse width modulation duty cycle adjustment amount formed this time is switched to the adjustment amplitude corresponding to the next lower level adjacent to the adjustment amplitude level, and the brushless motor is controlled according to the adjusted pulse width modulation duty cycle adjustment amount. When the updated flow comparison result indicates that the deviation between the current outflow rate and the target outflow rate is within the preset deviation threshold range and the set conditions are maintained, the current control state of the brushless motor is maintained, and no new pulse width modulation duty cycle adjustment is generated.

10. An automatic flow rate regulation system for a groundwater sampling device, used to execute the automatic flow rate regulation method according to any one of claims 1 to 9, characterized in that, It includes a handheld terminal, a control box, and a submersible pump. The submersible pump is equipped with a brushless motor, and the control box is equipped with a wireless communication module, a control module, a speed regulation module, and a drive module. The wireless communication module receives the target water flow rate input by the handheld terminal and sends it to the control module; The control module collects the voltage and current information of the submersible pump, determines the operating power, and determines the current water flow rate according to the preset correspondence between the operating power and the water flow rate. It compares the target water flow rate with the current water flow rate to form a flow rate comparison result, determines the deviation direction based on the flow rate comparison result, and forms a pulse width modulation duty cycle adjustment amount based on the deviation direction. The speed control module controls the drive module to drive the brushless motor according to the pulse width modulation duty cycle adjustment amount; After the brushless motor's operating state changes, the control module re-collects the voltage and current information, updates the operating power, the current outflow rate, and the flow rate comparison result, and generates a new pulse width modulation duty cycle adjustment amount based on the updated flow rate comparison result.

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