A method and system for calibrating flow feedback of an electronic pump

Abstract

The present application relates to an electronic pump flow feedback calibration method and system, and to the technical field of water pumps, a power calculation step, calculating the input power value of the motor, a standard establishment step, establishing a standard operation plane of the water pump according to a water pump of a performance standard, evenly setting a plurality of different water resistances therein, and obtaining a curve K1-Kn, adding a constant speed curve of a standard performance water pump to the operation plane, and the intersection of the constant speed curve and the water resistance curve is the steady-state operation point of the standard performance water pump at a speed of Ln under a Kn water resistance, and obtaining the operation parameters of the water pump at this steady-state operation point; a fitting step, fitting according to data, obtaining a standard flow equation O; a calibration step, obtaining an observed flow value B through the standard flow equation O, obtaining an actual flow value C, obtaining a flow deviation value ΔQ=C-B, and correcting the standard flow equation O with reference to the flow deviation value ΔQ to obtain a new standard flow equation N. The present application has the advantage of being able to reduce errors.

Description

Technical Field

[0001] The present application relates to the technical field of water pumps, and in particular to a flow feedback calibration method and system for an electronic pump. Background Art

[0002] With the popularity of electronic water pumps, stainless steel centrifugal pumps in various industries have been replaced by electronic water pumps in many occasions, such as cooling water pumps in chillers used in the laser field. This laser chiller system is generally equipped with a no-flow alarm system. This system originally used a turbine flow sensor to detect the flow rate. The advantages of this flow meter are its high precision and stability, and the disadvantage is that the performance of the flow meter will be affected by the distortion of the incoming flow velocity distribution and the rotational flow, causing the chiller to falsely alarm when there is flow. Therefore, the current material flow alarm system in the chiller market has gradually transformed into using an electronic pump with a flow feedback function to determine the current flow in the pipeline. This can not only optimize the overall system for the chiller, but also reduce costs. However, measuring the pipeline flow for electronic pumps also has the problem of accuracy deviation, because for a single pump, the flow can be adjusted according to the actual performance, but for mass-produced pumps, there are great differences between the motors and controllers produced by the theoretical design and the actual manufacturing process. If the flow is judged according to the performance of a single pump, there will be a large deviation for the flow on the mass-produced pump. Summary of the invention

[0003] In view of the deficiencies in the prior art, one of the purposes of the present application is to provide an electronic pump flow feedback calibration method and system, which has the advantage of being able to reduce errors.

[0004] The above-mentioned purpose of the present application is achieved through the following technical solutions:

[0005] An electronic pump flow feedback calibration method and system, power calculation steps, and calculation of the input power value of the motor , standard establishment step, according to the performance standard water pump, establish the standard operation plane of the water pump, evenly set a number of different water resistances in it, and get the curve K1-Kn. Add the constant speed curve of the standard performance water pump to the operation plane to get the curve L1-Ln. The intersection of the constant speed curve and the water resistance curve is the steady-state operation point of the standard performance water pump at the speed of Ln under the water resistance of Kn. At this steady-state operation point, get the operation parameters of the water pump, which include the flow rate of the current pipeline, the speed of the water pump and the input power of the water pump; fitting step, fit according to the data to get the standard flow equation O; calibration step, get the observed flow value B through the standard flow equation O, get the actual flow value C, get the flow deviation value ΔQ= CB, refer to the flow deviation value ΔQ to correct the standard flow equation O, and get a new standard flow equation N.

[0006] In a preferred example, the present application can be further configured as follows: when obtaining the observed flow value B, B is the average flow value within X time.

[0007] In a preferred example, the present application can be further configured as follows: the input power value of the motor It is obtained by the following formula: , where q and d represent the cross axis and direct axis respectively. is the quadrature axis voltage, is the quadrature axis current, is the direct axis voltage, is the direct axis current.

[0008] In a preferred example, the present application can be further configured as follows: it also includes a setting step, obtaining an actual flow curve through a standard flow equation N, and setting a response point on the actual flow curve.

[0009] In a preferred example, the present application can be further configured as follows: multiple response points can be set, and the multiple response points are not the same value.

[0010] The present application also discloses an electronic pump flow feedback calibration system, including a control module, a self-learning module and a flow estimation module. The flow estimation module stores a standard flow equation O. The control module sends a calibration signal to the self-learning module. After receiving the calibration signal, the self-learning module obtains an actual flow value C. The flow estimation module obtains the actual flow value C and calculates the observed flow value B. ΔQ is obtained through B and C, and the standard flow equation O is corrected with reference to the flow deviation value ΔQ to obtain a new standard flow equation N.

[0011] This application has the following advantages:

[0012] After completing the water pump standard curve, the water pump flow value can be calibrated through the user's external command, that is, the flow calibration self-learning function. Through flow self-learning and observation and monitoring of the water pump flow, the error can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the operating status diagram of the water pump in this application.

[0014] Figure 2 This is the calibration curve diagram of the water pump in this application.

[0015] Figure 3 This is the alarm point and recovery point diagram of this application. DETAILED DESCRIPTION

[0016] The present application is further described in detail below in conjunction with the accompanying drawings.

[0017] Reference Figure 1-Figure 3, is a flow feedback calibration method for an electronic pump disclosed in the present application, comprising the following steps: a power calculation step, calculating the input power value of the motor , the input power value of the motor It is obtained by the following formula: , where q and d represent the cross axis and direct axis respectively. is the quadrature axis voltage, in V. is the quadrature axis current, in A. is the direct axis voltage, unit V, is the direct-axis current, unit A, (the quadrature-axis voltage, quadrature-axis current, direct-axis voltage, and direct-axis current are the components of the fictitious dq coordinate system in the FOC control of the motor. They are the values ​​obtained after mathematical transformation (Park transformation and Clark transformation) of the abc three-phase current. In principle, they do not have actual units, but according to their actual meanings, their units can also be expressed in V, A). The standard establishment steps are to establish a standard operating plane for the water pump based on the performance standard, in which multiple different water resistances are evenly set, and the curve K1-Kn can be obtained. The constant speed curve of the standard performance water pump is added to the operation plane to obtain the curve L1-Ln. The intersection of the constant speed curve and the water resistance curve is the steady-state operation point of the standard performance water pump at Ln speed under Kn water resistance. At this steady-state operation point, the operation parameters of the water pump are obtained, including the flow rate of the current pipeline, the water pump speed and the water pump input power; the fitting step, fitting according to the data, to obtain the standard flow equation O; the calibration step, obtaining the observed flow value B through the standard flow equation O, obtaining the actual flow value C, obtaining the flow deviation value ΔQ= CB, and correcting the standard flow equation O with reference to the flow deviation value ΔQ to obtain a new standard flow equation N. When obtaining the observed flow value B, B is the average flow rate within X time. After amplifying the data obtained in the standard establishment step, perform unit conversion, and substitute the converted data into the fitting step. The setting step, obtain the actual flow curve through the standard flow equation N, set the response point on the actual flow curve, and multiple response points can be set, and multiple response points are not the same value. In this embodiment, there are two response points, one is an alarm point and the other is a recovery point.

[0018] The present application also discloses an electronic pump flow feedback calibration system, including a control module, a self-learning module and a flow estimation module. The flow estimation module stores a standard flow equation O. The control module sends a calibration signal to the self-learning module. After receiving the calibration signal, the self-learning module obtains an actual flow value C. The flow estimation module obtains the actual flow value C and calculates the observed flow value B. ΔQ is obtained through B and C, and the standard flow equation O is corrected with reference to the flow deviation value ΔQ to obtain a new standard flow equation N.

[0019] Furthermore, the above steps are further elaborated through the following description. It is worth noting that, in the following text, S100, S200, and S300 do not necessarily represent a certain order.

[0020] S100: The instantaneous change in motor control can be obtained through the motor control module to calculate the input power of the motor

[0021]

[0022] In the formula, q and d represent the quadrature axis and the direct axis respectively. is the quadrature axis voltage, is the quadrature axis current, is the direct axis voltage, is the direct axis current;

[0023] The controller can calculate the input power value of the motor under the corresponding working conditions through the above formula. .

[0024] S200: See Figure 1 , a standard operating plane of the water pump can be established based on a water pump with standard performance, and multiple different water resistances can be evenly set in it to obtain K1-Kn. Then the constant speed curve of the standard performance water pump is added to the operating plane to obtain L1-Ln. The intersection of the constant speed curve and the water resistance curve is the steady-state operating point of the standard performance water pump at Ln speed under Kn water resistance. At this steady-state operating point, the operating parameters of the water pump can be obtained, including the current pipeline flow, water pump speed and water pump input power;

[0025] Generally speaking, in situations where motors are used, a general formula is followed.

[0026] in is the input power, in KW, is the speed, unit is r / min, It is the torque, in N·m.

[0027] This also introduces three concepts: constant power operation, constant speed operation and constant torque operation. In the water pump industry, when the load is light (that is, when the output torque is small), it is generally operated at a constant speed, that is, It can maintain the maximum speed, at this time the input power It increases mainly with the increase of load (i.e. output torque). When the load (i.e. output torque) and input power gradually increase to a certain extent, it switches to constant power operation. At this time, if the load (i.e. output torque) continues to increase, the pump will reduce the speed. To maintain a constant input power.

[0028] Figure 1 In the figure, K1-K8 are different water resistance curves; L1-L3 are constant speed curves at different speeds;

[0029] Different valve openings correspond to different water resistance curves. The intersection points of the water resistance curve and the constant speed curve, J1-J8 (recorded as marking points), are connected into a curve, which is the actual operation curve corresponding to the water pump when the valve is switched on and off. Therefore, the flow, speed and power values ​​at each marking point can be obtained.

[0030] Figure 1 The reasons why J6, J7, and J8 are not on the same constant speed curve are as follows:

[0031] After measuring J6, the motor starts to enter the constant power mode (the input power at J6 To limit power ), that is, according to the above formula, before reaching the limit power, Follow becomes larger as the power reaches the limit, Get bigger, Therefore, after J6, the running speed of the motor will slowly decrease as the valve becomes larger, causing J7 and J8 to be on different constant speed curves.

[0032] According to this principle, the water resistance curve, that is, the valve opening, can be evenly set, and the running speed of the motor can be controlled to make the water pump run at Figure 1 At points J1, J2, J3, J4, J5, J6, J7, and J8 in the circuit, the input power, actual speed, and actual flow rate of the water pump when the motor is running at these points are taken out to obtain a set of water pump operation data.

[0033] S300: fitting the data to obtain a standard flow equation O; entering the standard flow equation O into a flow estimation module, and the flow estimation module can obtain a standard flow value by calculating the equation;

[0034] Software simulation can be used to fit the above data, so that each data is calibrated to the corresponding plane or curved surface, thereby calculating the standard flow equation O.

[0035] S400: Calibrate the batch water pump through the flow self-learning module and the flow estimation module;

[0036] S410: Reference Figure 2, by obtaining the observed flow value (such as 1050L / min, flow B) and the actual flow value (such as 1120L / min, flow C) at a certain flow point (such as setting 1000L / min, flow A) (e.g., 1050L / min obtained by the controller according to the above standard flow equation) and the actual flow value (e.g., 1120L / min obtained by the sensor, flow C), the flow deviation value ΔQ (CB) is obtained;

[0037] S420: By using the flow deviation value ΔQ (CB), the standard flow formula is increased by the deviation to obtain a new flow equation N: F(x,y,z)=f(x,y,z)+ΔQ to obtain the actual flow curve. The new flow equation N: F(x,y,z) is the standard flow equation for this batch of water production pumps. It is worth noting that in Figure 2 There are two observation curves in the figure, which means that the observation curve is different from the actual flow curve for different pumps. Therefore, whether the observed curve is above or below the actual flow curve should be determined according to the actual situation. Therefore, two curves are drawn here.

[0038] S500: Set alarm point and recovery point;

[0039] like Figure 3 As shown in the figure, after obtaining the actual flow curve, the response points (flow alarm point and recovery point) are set. When the flow is lower than the alarm point, the alarm signal is output through the controller for alarm or other actions. In order to avoid frequent alarms or excessive feedback, the recovery point is set higher than the alarm point. When the flow recovers, it will not be restored until it exceeds the recovery point, that is, the alarm is cancelled. The state between the recovery point and the alarm point is maintained, that is, in the middle hysteresis zone, the state before entering the hysteresis zone is kept unchanged, that is, it is in the alarm state.

[0040] In this method, the calibration point can be set as the alarm point, and the water pump is installed in a pipeline with a fixed flow rate as the calibration point flow rate. After the water pump flow rate stabilizes, a calibration instruction is sent to the controller. After the controller receives this instruction, it starts to monitor and filter the current flow value. After X seconds, the controller will observe an average flow value during this period of time. According to the error between this observed value and the actual flow value, ΔQ can be obtained. The controller can obtain the actual observation curve by translating the observation curve up and down by the value of ΔQ.

[0041] The implementation principle of this embodiment is: after completing the water pump standard curve, a calibration of the water pump flow value can be achieved through the user's external command, that is, the flow calibration self-learning function, to achieve observation and monitoring of the water pump flow, and precise control of the flow alarm point and recovery point.

[0042] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for calibrating flow feedback of an electronic pump, characterized in that: Power calculation steps, calculate the input power value of the motor , standard establishment steps, according to the performance standard water pump, establish the standard operation plane of the water pump, evenly set a number of different water resistances in it, and obtain the water resistance curve K1-Kn, add the constant speed curve of the standard performance water pump to the operation plane, and you can get the curve L1-Ln, the intersection of the constant speed curve and the water resistance curve is the steady-state operation point of the standard performance water pump at the speed of Ln under the water resistance of Kn, at this steady-state operation point, get the operation parameters of the water pump, the operation parameters include the current pipeline flow, water pump speed and water pump input power; The fitting step is to fit the operating parameters to obtain the standard flow equation O; The calibration step is to obtain the observed flow value B through the standard flow equation O, obtain the actual flow value C, and obtain the flow deviation value ΔQ= CB. The standard flow equation O is corrected with reference to the flow deviation value ΔQ to obtain a new standard flow equation N.

2. The electronic pump flow feedback calibration method according to claim 1, characterized in that: When obtaining the observed flow value B, B is the average flow value within the X time period.

3. The electronic pump flow feedback calibration method according to claim 1, characterized in that: Motor input power value It is obtained by the following formula: , where q and d represent the cross axis and direct axis respectively. is the quadrature axis voltage, is the quadrature axis current, is the direct axis voltage, is the direct axis current.

4. The electronic pump flow feedback calibration method according to claim 1, characterized in that: The method also includes a setting step of obtaining an actual flow curve through a standard flow equation N and setting a response point on the actual flow curve.

5. The electronic pump flow feedback calibration method according to claim 4, characterized in that: Multiple response points can be set, and multiple response points do not have the same value.

6. An electronic pump flow feedback calibration system, using an electronic pump flow feedback calibration method as claimed in any one of claims 1 to 5, characterized in that: It includes a control module, a self-learning module and a flow estimation module. The flow estimation module stores a standard flow equation O. The control module sends a calibration signal to the self-learning module. After receiving the calibration signal, the self-learning module obtains the actual flow value C. The flow estimation module obtains the actual flow value C and calculates the observed flow value B. ΔQ is obtained through B and C, and the standard flow equation O is corrected with reference to the flow deviation value ΔQ to obtain a new standard flow equation N.

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