Flow control method, circuit and apparatus

Abstract

The present application provides a flow control method, circuit and apparatus, applicable to the technical field of data processing. The method comprises: determining that a current flow rate of a liquid is greater than or equal to a first flow rate threshold, but less than a second flow rate threshold, and driving a first controller to control a valve, wherein the valve is used for controlling the flow of the liquid, and the second flow rate threshold is greater than the first flow rate threshold; inputting a difference result between the current flow rate of the liquid and the second flow rate threshold into a second controller to obtain a target control parameter for controlling the first controller; and using the target control parameter to adjust the first controller, so as to control the valve. In this way, the control parameter of the first controller is adjusted by the second controller, so as to increase the damping of the first controller. Stable control of a small liquid flow is achieved by means of two controllers, thereby improving the precision of flow control.

Description

Flow control method, circuit and device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 21, 2023, with application number 202311774621.0 and invention name “A flow control method, circuit and device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of data processing technology, and in particular to a flow control method, circuit, and device. Background Art

[0003] A turbine flowmeter consists of a turbine and an externally mounted sensor. When liquid flows into the turbine, the impeller rotates. The sensor detects the speed of the internal impeller and uses this speed to determine the flow rate of the liquid. In practice, a turbine flowmeter can achieve quantitative liquid flow by controlling a ball valve within the turbine.

[0004] When an impeller shifts from a stationary state to a rotating state, it must overcome its own rotational inertia to rotate. Therefore, when a turbine flowmeter operates at low flow rates, the impact of the small liquid flow rate is insufficient to drive the impeller's rotation, causing the measured flow rate to suddenly drop to zero. In this situation, the control feedback in the device suddenly increases, causing the control loop to oscillate and making it impossible to stably control the flow rate. Consequently, current turbine flowmeters have low control accuracy and are unable to stably control even small liquid flows. Summary of the Invention

[0005] In view of this, the present application provides a flow control method, circuit and device, which can improve the flow control accuracy and stably control smaller liquid flow rates.

[0006] To solve the above problems, the technical solutions provided by this application are as follows:

[0007] A first aspect of the present application provides a flow control method, the method comprising:

[0008] determining that a current flow rate of the liquid is greater than or equal to a first flow rate threshold but less than a second flow rate threshold, and driving a first controller to control a valve, the valve being used to control the flow rate of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold;

[0009] inputting a difference between the current flow rate of the liquid and the second flow rate threshold into a second controller to obtain a target control parameter for controlling the first controller;

[0010] The first controller is adjusted using the target control parameter to control the valve.

[0011] In one possible implementation, the method further includes:

[0012] Determine a minimum flow detection point by fine-tuning the valve controller, wherein the minimum flow detection point has a first flow rate threshold;

[0013] The first flow rate threshold value with a preset multiple is used as the second flow rate threshold value.

[0014] In one possible implementation, it is determined that the current flow rate of the liquid is less than a first flow rate threshold, and the method further includes: starting a small flow time resolver and a PWM flow controller;

[0015] Determining the closing time of the valve using the small flow time resolver;

[0016] Transmitting the closing time of the valve to the PWM flow controller to control the valve to close, and the first controller stops working;

[0017] After the closing time of the valve is reached, the current flow rate of the liquid is adjusted to the second flow rate threshold, the first controller is started, and the PWM flow controller is closed.

[0018] In one possible implementation, the method further includes:

[0019] Get the impeller speed;

[0020] A current flow rate of the liquid is determined based on the impeller rotational speed.

[0021] A second aspect of the present application provides a flow control circuit, the flow control circuit comprising:

[0022] A flow rate detection module, a first controller, a second controller, a flow rate threshold module, a differentiator, and a valve;

[0023] The input end of the first controller is respectively connected to the output end of the flow rate detection module, the output end of the second controller and the output end of the flow rate threshold module;

[0024] The input end of the second controller is connected to the output end of the differentiator;

[0025] The input end of the differentiator is connected to the output end of the flow rate detection module and the output end of the flow rate threshold module respectively;

[0026] The output end of the first controller is connected to the input end of the valve, and is used to control the flow of the liquid through the valve.

[0027] In one possible implementation, the flow control circuit further includes:

[0028] Flow recorder, small flow time resolver and PWM flow controller;

[0029] The input end of the flow recorder is connected to the output end of the flow velocity detection module, and the output end of the flow recorder is connected to the input end of the small flow time resolver;

[0030] The input end of the PWM flow controller is connected to the output end of the flow threshold module and the output end of the small flow time resolver respectively, and the output end of the PWM flow controller is connected to the input end of the valve.

[0031] A third aspect of the present application provides a flow control device, comprising:

[0032] a driving unit, configured to determine that a current flow rate of the liquid is greater than or equal to a first flow rate threshold but less than a second flow rate threshold, and drive a first controller to control a valve, the valve being configured to control a flow rate of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold;

[0033] an acquiring unit, configured to input a difference between the current flow rate of the liquid and the second flow rate threshold into a second controller to obtain a target control parameter for controlling the first controller;

[0034] A control unit is configured to adjust the first controller using the target control parameter to control the valve.

[0035] In one possible implementation, the apparatus further includes a first determining unit and a second determining unit:

[0036] The first determining unit is configured to determine a minimum flow detection point by fine-tuning the valve controller, wherein the minimum flow detection point has a first flow rate threshold;

[0037] The second determining unit is configured to use a preset multiple of the first flow rate threshold as the second flow rate threshold.

[0038] In one possible implementation, it is determined that the current flow rate of the liquid is less than a first flow rate threshold, and the apparatus further includes: a starting unit and an adjusting unit;

[0039] The starting unit is used to start the small flow time resolver and the PWM flow controller; and use the small flow time resolver to determine the closing time of the valve;

[0040] The driving unit is further configured to transmit the closing duration of the valve to the PWM flow controller to control the valve to close, and the first controller to stop working;

[0041] The adjustment unit is used to adjust the current flow rate of the liquid to the second flow rate threshold after the closing time of the valve is reached, start the first controller, and close the PWM flow controller.

[0042] In one possible implementation, the apparatus further includes a third determining unit:

[0043] The acquisition unit is further used to acquire the impeller speed;

[0044] The third determining unit is configured to determine a current flow rate of the liquid based on the impeller rotation speed.

[0045] It can be seen that this application has the following beneficial effects:

[0046] The present application provides a flow control method, which first determines that the current flow rate of the liquid is greater than or equal to a first flow rate threshold but less than a second flow rate threshold, drives a first controller to control a valve, and the valve is used to control the flow of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold; inputs the difference between the current flow rate of the liquid and the second flow rate threshold into a second controller to obtain a target control parameter for controlling the first controller; and uses the target control parameter to adjust the first controller to control the valve. In this way, the control parameters of the first controller are adjusted by the second controller to increase the damping of the first controller. The dual controller method is used to achieve stable control of smaller liquid flows and improve flow control accuracy.

[0047] The embodiments of the present application also provide a circuit for implementing the above method and a device corresponding to the above method, which have the same beneficial effects as the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG1 is a schematic structural diagram of a turbine flowmeter provided in an embodiment of the present application;

[0049] FIG2 is a schematic structural diagram of a flow control circuit provided in an embodiment of the present application;

[0050] FIG3 is a flow chart of a flow control method provided in an embodiment of the present application;

[0051] FIG4 is a waveform diagram of a flow control provided in an embodiment of the present application;

[0052] FIG5 is a schematic structural diagram of a flow control device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0054] In this application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0055] Turbine flow sensors are primarily categorized by detection type: photoelectric and electromagnetic. Photoelectric detection offers higher accuracy than electromagnetic detection, but has certain requirements for liquid transparency, while electromagnetic detection does not. It should be noted that the turbine flow sensors described in this application are not limited to the aforementioned types. For ease of description, the following detailed description will focus on an electromagnetic detection turbine flowmeter as an example.

[0056] Refer to Figure 1, which is a schematic structural diagram of a turbine flowmeter provided in an embodiment of the present application. The turbine flowmeter includes a blade 1 with a magnetic material, a turbine generator 2, a magnetic sensor (HALL sensor) 3, a ball valve 5 (valve) controlled by a motor 4, a water flow path 6, and a magnet (not shown in the figure). When liquid flows into the turbine flowmeter as shown in Figure 1, it causes the impeller to rotate. The HALL sensor 3 detects the rotation speed of its built-in impeller and uses the rotation speed to determine the flow rate of the liquid at this time. In addition, the turbine flowmeter can achieve the purpose of liquid quantification by controlling the ball valve 5.

[0057] The HALL sensor 3 requires a magnetic field to participate in detection, so that the impeller and the magnet can generate a certain amount of attraction. At the same time, when the impeller switches from being stationary to rotating, it needs to overcome the rotational inertia required for its own rotation to rotate. Therefore, when the turbine flowmeter is operating at a low flow rate, the impact generated by the small liquid flow is not enough to drive the rotation of the impeller, causing the flow rate detection to suddenly drop to 0. The control feedback will suddenly increase, causing the control loop to oscillate, making it impossible to stably control the flow rate. In other words, the control accuracy of the current turbine flowmeter is low, and it is impossible to stably control the situation of small liquid flow rates.

[0058] Based on this, the present application provides a flow control method and device, as well as a flow control circuit to implement the flow control method. First, it is determined that the current flow rate of the liquid is greater than or equal to the first flow rate threshold, but less than the second flow rate threshold, and the first controller is driven to control the valve, which is used to control the flow of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold; the difference between the current flow rate of the liquid and the second flow rate threshold is input to the second controller to obtain the target control parameter for controlling the first controller; the target control parameter is used to adjust the first controller to control the valve. In this way, the control parameters of the first controller are adjusted by the second controller to increase the damping of the first controller. The dual controller method is used to achieve stable control of smaller liquid flows and improve the flow control accuracy.

[0059] To facilitate understanding of the technical solution provided by the embodiments of the present application, a flow control method, circuit, and device provided by the embodiments of the present application are described below with reference to the accompanying drawings.

[0060] Referring to FIG. 2 , FIG. 2 is a schematic diagram of the structure of a flow control circuit provided in an embodiment of the present application. The flow control circuit includes a flow rate detection module, a first controller, a second controller, a flow rate threshold module, a differentiator, and a valve. The first controller and the second controller are proportional-integral-differential (PID) controllers.

[0061] The input end of the first controller is respectively connected to the output end of the flow rate detection module, the output end of the second controller, and the output end of the flow rate threshold module. The output end of the first controller is connected to the input end of the valve, which is used to control the flow rate of the liquid through the valve. The input end of the second controller is connected to the output end of the differentiator, and the input end of the differentiator is respectively connected to the output end of the flow rate detection module and the output end of the flow rate threshold module.

[0062] The flow rate detection module is used to detect the current flow rate of the liquid. The differentiator is used to determine the difference between the current flow rate of the liquid and the second flow rate threshold. The flow rate threshold module is used to determine the first flow rate threshold and the second flow rate threshold. The second controller is used to adjust the PID control parameters of the first controller. Based on the output of the flow rate detection module, the output of the second controller, and the output of the flow rate threshold module, the first controller accurately controls the valve operation, achieving stable control of relatively small liquid flow rates.

[0063] To further reduce the flow meter's controllable lower limit, pulse width modulation (PWM) control technology can be added to the flow control circuit to achieve finer control of the flow rate. In one possible implementation, the flow control circuit also includes: a flow recorder, a low-flow time resolver, and a PWM flow controller.

[0064] The flow recorder's input is connected to the flow rate detection module's output, which is then connected to the input of the micro-flow time solver. The PWM flow controller's input is connected to the flow rate threshold module's output and the micro-flow time solver's output, respectively, while the PWM flow controller's output is connected to the valve's input.

[0065] The flow recorder is used to determine the cumulative flow rate of the liquid based on the current flow rate output by the flow rate detection module. The cumulative flow rate is the sum of the flow rates of the liquid flowing into the valve during a cycle from the start of the turbine flowmeter operation to the real time. The low flow time solver is used to determine the valve closing time.

[0066] The total amount of liquid required to be input within a cycle is a preset value. Flow rate calculation is performed within the detectable range. Specifically, a cycle is defined as the time it takes for the liquid flow rate to increase from the second flow rate threshold to the first flow rate threshold. The first flow rate threshold is the minimum flow rate detectable by the flow rate detection module. When the current flow rate of the detected liquid falls below the first flow rate threshold, i.e., the detected flow rate suddenly drops to zero, the cumulative flow rate of the liquid input meets the preset value required within the cycle.

[0067] The closing time required for the valve is calculated according to the micro-flow time solver, that is, the time the valve is kept in the closed state is calculated. In one possible implementation, the closing time of the valve is calculated by the micro-flow time solver based on the data of the flow recorder. If the flow value of the input liquid has reached the preset value at a certain time point in the cycle, the valve can be closed for the remaining time in the cycle to wait for the next cycle to execute liquid input again. That is, the difference between the cycle length and the time used to input the preset value of liquid is the closing time of the valve. The closing time of the valve is transmitted to the PWM flow controller to control the valve to close, and accordingly, the first controller stops working.

[0068] After the closing time is reached, the valve opens, adjusting the current flow rate of the liquid to the second flow rate threshold. When the current flow rate of the liquid reaches the second flow rate threshold, the next cycle begins, the PWM flow controller stops operating, and the first controller starts operating. By comprehensively calculating the flow rate from the second flow rate threshold to the first flow rate threshold and the valve closing time, a control method with higher accuracy than the minimum flow rate detected by the magnetic sensor is achieved.

[0069] An overdamped dual PID control loop combined with PWM technology achieves control of relatively small flow rates. The first controller in the overdamped dual PID control system is a flow control PID. Its input is the current flow rate of the liquid, and its output is the valve opening. Valve opening refers to the degree to which the valve is open or closed, i.e., the volume occupied by the valve or channel over a given time period due to changes in its seat volume or channel volume. The second controller is a control PID for the PID parameters of the first controller. Its input is the difference between the current flow rate and a second flow rate threshold, and its output is the target control parameter of the first controller. This increases the control damping of the first controller to prevent the flow rate from suddenly dropping to zero.

[0070] The flow control method provided in the embodiment of the present application can be applied to the flow control circuit provided in the above embodiment. Referring to FIG3 , FIG3 is a flow chart of the flow control method provided in the embodiment of the present application, which specifically includes S301 - S303 .

[0071] S301: Determine that the current flow rate of the liquid is greater than or equal to a first flow rate threshold but less than a second flow rate threshold, drive a first controller to control a valve, the valve being used to control the flow of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold.

[0072] The current flow rate of the liquid is detected. When the current flow rate of the liquid reaches the second flow rate threshold with a decreasing trend but is not lower than the first flow rate threshold, the first controller is driven to control the valve.

[0073] In one possible implementation, the current flow rate of the liquid can be obtained based on the impeller speed. The method further includes: obtaining the impeller speed; and determining the current flow rate of the liquid based on the impeller speed. The impeller speed can be obtained by a Hall sensor 3. The impeller speed is related to the liquid flow rate, and the current flow rate of the liquid can be calculated based on the impeller speed.

[0074] The second flow rate threshold, also known as the non-steady-state threshold, is used to distinguish between stable and unstable flow intervals. If the current flow rate is greater than or equal to the first flow rate threshold but less than the second flow rate threshold, it indicates that the flow rate is in the non-stable interval and is slow. A second controller can be used to achieve more precise control.

[0075] In one possible implementation, the method further includes: determining a minimum flow detection point by fine-tuning a valve controller, the minimum flow detection point having a first flow rate threshold; and using a preset multiple of the first flow rate threshold as the second flow rate threshold.

[0076] It should be noted that the minimum control accuracy of the turbine flowmeter is determined by the physical parameters of the entire device, mainly depending on the minimum control accuracy of the valve. The control accuracy of each device may vary.

[0077] The valve controller is used to control the size of the valve opening. By fine-tuning the valve controller, the minimum flow detection point can be determined. The minimum flow detection point has a minimum flow rate, and the minimum flow rate is used as the first flow rate threshold. The first flow rate threshold with a preset multiple is used as the second flow rate threshold. The preset multiple can be set based on actual conditions. In the embodiment of the present application, the preset multiple can be any value between 1.5 times and 2 times. In the embodiment of the present application, the unstable interval is between the first flow rate threshold and the second flow rate threshold. Using the preset multiple of the first flow rate threshold as the second flow rate threshold can control the valve before the minimum flow rate is reached to prevent the flow rate from suddenly dropping to 0.

[0078] In another possible implementation, under normal flow control parameter regulation, the maximum flow rate change that does not result in the flow rate detection module measuring 0 is used as the second flow rate threshold. The second flow rate threshold can be fine-tuned to an appropriate point during production.

[0079] When it is determined that the current flow rate has reached the second flow rate threshold with a decreasing trend but has not reached the first flow rate threshold, the second controller is activated to control the PID control parameters of the first controller. The PID control parameters of the first controller are adjusted based on the second controller (the default setting is slight overdamping before adjustment) to control the opening of the valve.

[0080] S302: Inputting the difference between the current flow rate of the liquid and the second flow rate threshold into the second controller to obtain a target control parameter for controlling the first controller.

[0081] The PID control parameters of the first controller are adjusted by the second controller. Specifically, based on the differential result calculated by the differentiator between the current flow rate of the liquid and the second flow rate threshold, the second controller determines the target control parameters for controlling the first controller based on the differential result, thereby increasing the damping of the overall control effect of the first controller.

[0082] S303: Utilize the target control parameter to adjust the first controller to control the valve.

[0083] The PID control parameters of the first controller are adjusted to the target control parameters so that the first controller controls the valve to operate at low flow, thereby achieving minimal fluctuation and controlling the current flow rate of the liquid to approach the second flow rate threshold to ensure stable operation of the turbine flowmeter.

[0084] Based on the contents of steps S301 to S303, it can be seen that when the current flow rate of the liquid is greater than or equal to the first flow rate threshold but less than the second flow rate threshold, the first controller controls the valve and inputs the difference between the current flow rate of the liquid and the second flow rate threshold into the second controller to obtain the target control parameter for controlling the first controller. The target control parameter is used to adjust the first controller to control the valve to achieve the purpose of controlling the liquid flow. The control parameters of the first controller are controlled by the second controller to increase the damping of the first controller. The dual controller approach achieves stable control of smaller liquid flow rates and improves flow control accuracy.

[0085] In another embodiment of the present application, when the current flow rate of the liquid is less than the minimum measurable flow rate, the dual PID controller cannot meet the flow control purpose, that is, the current flow rate of the liquid is less than the first flow rate threshold, the first controller controls the valve to adjust in the closing direction, and the flow rate detection module detects a flow rate of 0, which will start the micro-flow time resolver and the PWM flow controller.

[0086] In one possible implementation, it is determined that the current flow rate of the liquid is less than a first flow rate threshold, and the method further includes: starting a micro-flow time resolver and a PWM flow controller; using the micro-flow time resolver to determine the closing time of the valve; transmitting the closing time of the valve to the PWM flow controller, controlling the valve to close, and stopping the first controller; after the closing time of the valve is reached, adjusting the current flow rate of the liquid to the second flow rate threshold, starting the first controller, and closing the PWM flow controller.

[0087] The total amount of liquid required to be input within a cycle is a preset value. The time it takes for the liquid flow rate to drop from the second flow rate threshold to the first flow rate threshold is a cycle. The cycle is a detectable unstable interval, and flow calculation is performed within the detectable unstable interval.

[0088] When the current flow rate of the detected liquid is less than the first flow rate threshold, that is, the detected flow rate suddenly drops to 0, indicating that the cumulative flow value of the liquid input during this cycle meets the required preset value. The small flow time solver is used to determine the closing time of the valve, that is, calculate the closing time from the valve closing to the next cycle.

[0089] The valve closing time is calculated by a micro-flow time solver based on data from the flow recorder. If the incoming liquid flow rate reaches the preset value at a certain point in the cycle, the valve is closed for the remaining time in the cycle, waiting for the next cycle to resume liquid input. The difference between the cycle duration and the time it takes to input the preset value of liquid is the valve closing time. This valve closing time is then transmitted to the PWM flow controller, which controls the valve closing and deactivates the first controller.

[0090] After the valve closing time is reached, the valve opens and adjusts the current flow rate of the liquid to the second flow rate threshold. When the current flow rate of the liquid reaches the second flow rate threshold, the next cycle begins, the PWM flow controller stops working, and the first controller starts working.

[0091] After the valve is opened, the liquid flow rate is controlled and adjusted to the second flow rate threshold. When the current flow rate of the liquid reaches the second flow rate threshold, the next cycle begins. The flow recorder's recorded data is reset, and the flow recorder records the accumulated flow value for the next cycle. The flow rate detection module normally detects the current flow rate of the liquid.

[0092] Since there are calculation errors when the valve is closed and opened, the flow value in this stage is calibrated to achieve more accurate flow control. By comprehensively calculating the flow rate in the unstable range and the valve closing time, smaller flow control can be achieved.

[0093] It should be noted that the liquid is continuously supplied to the turbine flowmeter, and after the valve is opened, the flow rate of the liquid increases from the first flow rate threshold to the second flow rate threshold within the detectable unstable range.

[0094] Referring to FIG4 , FIG4 is a waveform diagram of a flow control provided by an embodiment of the present application, wherein S1 represents the stage in which the first controller operates, and S2 represents the stage in which the PWM flow controller operates. When the current flow rate of the liquid is less than the second flow rate threshold but greater than the first flow rate threshold, the first controller is in the operating state and the PWM flow controller is in the off state. When the current flow rate of the liquid is less than the first flow rate threshold, the first controller is in the off state and the PWM flow controller is in the operating state. This enables highly accurate flow control.

[0095] It should be noted that the embodiment of the present application uses an electromagnetic detection type turbine flowmeter as an example for illustration. Since the electromagnetic detection type turbine flowmeter has a smaller flow rate working condition and higher working accuracy when working, the application of the solution described in the embodiment of the present application can expand the application range of this type of flowmeter. Although the photoelectric detection type flowmeter does not involve the magnetic field attraction, it also needs to overcome the thrust required for its own rotation. Therefore, the solution described in the embodiment of the present application can also be used to achieve a more accurate flow detection result. The embodiment of the present application is a turbine flowmeter, which improves its control accuracy, but does not limit the object of use. The solution of the embodiment of the present application is also applicable to other control devices with a starting step to achieve high-precision control.

[0096] The aforementioned embodiment of the present application provides a flow control method based on the above. Next, a flow control device provided in the embodiment of the present application is described. This device is applied to a flow control circuit and executes the method shown in FIG3 . The function of the flow control device is described. A schematic structural diagram of the flow control device is shown in FIG5 , which includes a drive unit 501 , an acquisition unit 502 , and a control unit 503 .

[0097] a driving unit 501 configured to determine that a current flow rate of the liquid is greater than or equal to a first flow rate threshold but less than a second flow rate threshold, and to drive a first controller to control a valve configured to control a flow rate of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold;

[0098] an acquiring unit 502 for inputting a difference between the current flow rate of the liquid and the second flow rate threshold into a second controller to obtain a target control parameter for controlling the first controller;

[0099] The control unit 503 is configured to adjust the first controller using the target control parameter to control the valve.

[0100] In one possible implementation, the apparatus further includes a first determining unit and a second determining unit:

[0101] The first determining unit is configured to determine a minimum flow detection point by fine-tuning the valve controller, wherein the minimum flow detection point has a first flow rate threshold;

[0102] The second determining unit is configured to use a preset multiple of the first flow rate threshold as the second flow rate threshold.

[0103] In one possible implementation, it is determined that the current flow rate of the liquid is less than a first flow rate threshold, and the apparatus further includes: a starting unit and an adjusting unit;

[0104] The starting unit is used to start the small flow time resolver and the PWM flow controller; and use the small flow time resolver to determine the closing time of the valve;

[0105] The driving unit 501 is further configured to transmit the closing duration of the valve to the PWM flow controller to control the valve to close, and the first controller to stop working;

[0106] The adjustment unit is used to adjust the current flow rate of the liquid to the second flow rate threshold after the closing time of the valve is reached, start the first controller, and close the PWM flow controller.

[0107] In one possible implementation, the apparatus further includes a third determining unit:

[0108] The acquisition unit 502 is further used to acquire the impeller speed;

[0109] The third determining unit is configured to determine a current flow rate of the liquid based on the impeller rotation speed.

[0110] An embodiment of the present application provides a flow control device, comprising a drive unit, an acquisition unit, and a control unit. The drive unit is used to determine whether the current flow rate of the liquid is greater than or equal to a first flow rate threshold, but less than a second flow rate threshold, and drive the first controller to control the valve, the valve being used to control the flow of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold; the acquisition unit is used to input the difference between the current flow rate of the liquid and the second flow rate threshold into the second controller to obtain a target control parameter for controlling the first controller; the control unit is used to use the target control parameter to adjust the first controller to control the valve. The control parameters of the first controller are adjusted by the second controller to increase the damping of the first controller. The dual controller method is used to achieve stable control of smaller liquid flows and improve flow control accuracy.

[0111] Example:

[0112] Embodiment 1: A flow control method, wherein the method comprises:

[0113] determining that a current flow rate of the liquid is greater than or equal to a first flow rate threshold but less than a second flow rate threshold, and driving a first controller to control a valve, the valve being used to control the flow rate of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold;

[0114] inputting a difference between the current flow rate of the liquid and the second flow rate threshold into a second controller to obtain a target control parameter for controlling the first controller;

[0115] The first controller is adjusted using the target control parameter to control the valve.

[0116] Embodiment 2: The flow control method according to embodiment 1, wherein the method further comprises:

[0117] Determine a minimum flow detection point by fine-tuning the valve controller, wherein the minimum flow detection point has a first flow rate threshold;

[0118] The first flow rate threshold value with a preset multiple is used as the second flow rate threshold value.

[0119] Embodiment 3: The flow control method according to embodiment 1 or 2, wherein it is determined that the current flow rate of the liquid is less than the first flow rate threshold, the method further comprising: starting a small flow time resolver and a PWM flow controller;

[0120] Determining the closing time of the valve using the small flow time resolver;

[0121] Transmitting the closing time of the valve to the PWM flow controller to control the valve to close, and the first controller stops working;

[0122] After the closing time of the valve is reached, the current flow rate of the liquid is adjusted to the second flow rate threshold, the first controller is started, and the PWM flow controller is closed.

[0123] Embodiment 4: The flow control method according to any one of embodiments 1 to 3, wherein the method further comprises:

[0124] Get the impeller speed;

[0125] A current flow rate of the liquid is determined based on the impeller rotational speed.

[0126] Embodiment 5: A flow control circuit, wherein the flow control circuit comprises:

[0127] A flow rate detection module, a first controller, a second controller, a flow rate threshold module, a differentiator, and a valve;

[0128] The input end of the first controller is respectively connected to the output end of the flow rate detection module, the output end of the second controller and the output end of the flow rate threshold module;

[0129] The input end of the second controller is connected to the output end of the differentiator;

[0130] The input end of the differentiator is connected to the output end of the flow rate detection module and the output end of the flow rate threshold module respectively;

[0131] The output end of the first controller is connected to the input end of the valve, and is used to control the flow of the liquid through the valve.

[0132] Embodiment 6: The flow control circuit according to embodiment 5, wherein the flow control circuit further comprises:

[0133] Flow recorder, small flow time resolver and PWM flow controller;

[0134] The input end of the flow recorder is connected to the output end of the flow velocity detection module, and the output end of the flow recorder is connected to the input end of the small flow time resolver;

[0135] The input end of the PWM flow controller is connected to the output end of the flow threshold module and the output end of the small flow time resolver respectively, and the output end of the PWM flow controller is connected to the input end of the valve.

[0136] Embodiment 7: A flow control device, wherein the device comprises:

[0137] a driving unit, configured to determine that a current flow rate of the liquid is greater than or equal to a first flow rate threshold but less than a second flow rate threshold, and drive a first controller to control a valve, the valve being configured to control a flow rate of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold;

[0138] an acquiring unit, configured to input a difference between the current flow rate of the liquid and the second flow rate threshold into a second controller to obtain a target control parameter for controlling the first controller;

[0139] A control unit is configured to adjust the first controller using the target control parameter to control the valve.

[0140] Embodiment 8: The flow control device according to embodiment 7, wherein the device further comprises a first determining unit and a second determining unit:

[0141] The first determining unit is configured to determine a minimum flow detection point by fine-tuning the valve controller, wherein the minimum flow detection point has a first flow rate threshold;

[0142] The second determining unit is configured to use a preset multiple of the first flow rate threshold as the second flow rate threshold.

[0143] Embodiment 9: The flow control device according to embodiment 7 or 8, wherein it is determined that the current flow rate of the liquid is less than the first flow rate threshold, the device further comprises: a starting unit and an adjusting unit;

[0144] The starting unit is used to start the small flow time resolver and the PWM flow controller; and use the small flow time resolver to determine the closing time of the valve;

[0145] The driving unit is further configured to transmit the closing duration of the valve to the PWM flow controller to control the valve to close, and the first controller to stop working;

[0146] The adjustment unit is used to adjust the current flow rate of the liquid to the second flow rate threshold after the closing time of the valve is reached, start the first controller, and close the PWM flow controller.

[0147] Embodiment 10: The flow control device according to any one of embodiments 7 to 9, wherein the device further comprises a third determining unit:

[0148] The acquisition unit is further used to acquire the impeller speed;

[0149] The third determining unit is configured to determine a current flow rate of the liquid based on the impeller rotation speed.

[0150] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device or device embodiment, since it is basically similar to the method embodiment, the description is relatively simple. For the relevant parts, refer to the partial description of the method embodiment. The device and device embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without making any creative efforts.

[0151] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flow control method, characterized in that: The method comprises: Determining that the current flow rate of the liquid is greater than or equal to a first flow rate threshold but less than a second flow rate threshold, driving a first controller to control a valve, the valve being used to control the flow rate of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold; Inputting the difference between the current flow rate of the liquid and the second flow rate threshold into the second controller to obtain a target control parameter for controlling the first controller; The first controller is adjusted using the target control parameter to control the valve.

2. The flow control method according to claim 1, characterized in that: The method further comprises: Determine a minimum flow detection point by fine-tuning the valve controller, wherein the minimum flow detection point has a first flow rate threshold; A preset multiple of the first flow rate threshold is used as the second flow rate threshold.

3. The flow control method according to claim 1, characterized in that: Determining that the current flow rate of the liquid is less than a first flow rate threshold, the method further comprises: starting a micro-flow time resolver and a PWM flow controller; Determining the closing time of the valve using the micro-flow time resolver; Transmitting the closing time of the valve to the PWM flow controller to control the valve to close, and the first controller stops working; After the closing time of the valve is reached, the current flow rate of the liquid is adjusted to the second flow rate threshold, the first controller is started, and the PWM flow controller is closed.

4. The flow control method according to claim 1, characterized in that: The method further comprises: Get the impeller speed; A current flow rate of the liquid is determined based on the impeller rotation speed.

5. A flow control circuit, characterized in that: The flow control circuit comprises: A flow rate detection module, a first controller, a second controller, a flow rate threshold module, a differentiator and a valve; The input end of the first controller is respectively connected to the output end of the flow rate detection module, the output end of the second controller and the output end of the flow rate threshold module; The input end of the second controller is connected to the output end of the differentiator; The input end of the differentiator is respectively connected to the output end of the flow rate detection module and the output end of the flow rate threshold module; The output end of the first controller is connected to the input end of the valve, and is used to control the flow of the liquid through the valve.

6. The flow control circuit according to claim 5, characterized in that: The flow control circuit also includes: Flow recorder, micro flow time resolver and PWM flow controller; The input end of the flow recorder is connected to the output end of the flow velocity detection module, and the output end of the flow recorder is connected to the input end of the small flow time resolver; The input end of the PWM flow controller is connected to the output end of the flow threshold module and the output end of the small flow time resolver respectively, and the output end of the PWM flow controller is connected to the input end of the valve.

7. A flow control device, characterized in that: The device comprises: a driving unit, configured to determine that a current flow rate of the liquid is greater than or equal to a first flow rate threshold but less than a second flow rate threshold, and drive a first controller to control a valve, wherein the valve is configured to control a flow rate of the liquid, wherein the second flow rate threshold is greater than the first flow rate threshold; an acquisition unit, configured to input a difference result between the current flow rate of the liquid and the second flow rate threshold into a second controller to obtain a target control parameter for controlling the first controller; A control unit is used to adjust the first controller using the target control parameter to control the valve.

8. The flow control device according to claim 7, characterized in that: The device also includes a first determining unit and a second determining unit: The first determination unit is used to determine a minimum flow detection point by fine-tuning the valve controller, and the minimum flow detection point has a first flow rate threshold; The second determining unit is configured to use a preset multiple of the first flow rate threshold as the second flow rate threshold.

9. The flow control device according to claim 7, characterized in that: Determining that the current flow rate of the liquid is less than a first flow rate threshold, the device further comprises: a starting unit and an adjusting unit; The starting unit is used to start the micro-flow time resolver and the PWM flow controller; and use the micro-flow time resolver to determine the closing time of the valve; The driving unit is further used to transmit the closing time of the valve to the PWM flow controller to control the valve to close, and the first controller stops working; The adjustment unit is used to adjust the current flow rate of the liquid to the second flow rate threshold after the closing time of the valve is reached, start the first controller, and close the PWM flow controller.

10. The flow control device according to claim 7, characterized in that: The device also includes a third determining unit: The acquisition unit is also used to acquire the impeller rotation speed; The third determination unit is used to determine the current flow rate of the liquid based on the impeller rotation speed.

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