A centrifugal pump module and variable frequency operation adjustment method thereof

Abstract

The present invention relates to the field of centrifugal pump operation regulation, and specifically to a centrifugal pump module and a variable frequency operation regulation method thereof. The method first obtains the speed data of the pump shaft of the centrifugal pump at each moment in a preset time period, the flow data of the water outlet pipe, and the pressure data of the water inlet pipe and the water outlet pipe, and fits the data points composed of the speed data and flow data at the same moment to obtain the fitting flow data of each speed data, and calculates the flow deviation at each moment, and obtains the pressure fluctuation degree at each moment according to the fluctuation of the pressure data of the local water inlet pipe at each moment, the pressure difference between the water outlet pipe and the water inlet pipe, and optimizes the PID controller based on the difference in the flow deviation and the pressure fluctuation degree at each moment, and the correlation between the flow data and the pressure data at each moment, and then adjusts the operation frequency of the centrifugal pump. The present invention can accurately adjust the working frequency of the centrifugal pump and improve the operation performance of the centrifugal pump.

Description

Technical Field

[0001] The invention relates to the field of centrifugal pump operation regulation, and in particular to a centrifugal pump module and a variable frequency operation regulation method thereof. Background Art

[0002] Centrifugal pump modules usually integrate the pump body, drive motor and control system, and are widely used in water supply, drainage, thermal cycle and other fields. Traditional centrifugal pump systems have problems with low efficiency and performance during operation, and are difficult to adapt to complex and changeable usage environments and working conditions. Currently, the main method used is variable frequency operation adjustment, which controls the speed of the centrifugal pump by adjusting the operating frequency of the centrifugal pump, thereby achieving flow control and improving the operating efficiency of the centrifugal pump module.

[0003] In the related art, during the operation of the centrifugal pump, a control signal is output to the frequency converter through a fixed-parameter PID controller, and the operating frequency and speed of the centrifugal pump are controlled by the frequency converter to meet the water flow demand. However, since the water flow is easily affected by external factors such as pipeline water pressure, the water flow in the pipeline is unstable, which leads to the inability to accurately adjust the operating frequency of the centrifugal pump by using the fixed-parameter PID controller output signal to control the frequency converter, thereby reducing the operating performance of the centrifugal pump. Summary of the invention

[0004] In order to solve the technical problem that the working frequency of a centrifugal pump cannot be accurately adjusted and the operating performance of the centrifugal pump is reduced by controlling the frequency converter by using the output signal of a PID controller with fixed parameters, the object of the present invention is to provide a centrifugal pump module and a variable frequency operation adjustment method thereof. The technical scheme adopted is as follows:

[0005] The present invention proposes a centrifugal pump module variable frequency operation adjustment method, the method comprising:

[0006] Obtaining the pump shaft speed data, the flow rate data of the water outlet pipe, and the pressure data of the water inlet pipe and the water outlet pipe of the centrifugal pump at each moment in a preset time period;

[0007] Fitting the data points composed of the rotation speed data and the flow data at the same time to obtain the fitted flow data of each rotation speed data; taking any time as the target time, and obtaining the flow deviation at the target time according to the difference between the flow data at the target time and the fitted flow data of the rotation speed data at the target time; obtaining the pressure fluctuation degree at the target time according to the fluctuation of the pressure data at each time of the water inlet pipe within the preset time domain of the target time, and the difference of the pressure data between the water inlet pipe and the water outlet pipe at the target time;

[0008] According to the difference between the flow deviation and the pressure fluctuation degree at each moment, and the correlation between the flow data and the pressure data at each moment, a pressure fluctuation constraint coefficient of the centrifugal pump is obtained; based on the pressure fluctuation constraint coefficient, a PID controller of the centrifugal pump is optimized to obtain an optimized PID controller;

[0009] Based on the optimized PID controller and frequency converter of the centrifugal pump, the operating frequency of the centrifugal pump is adjusted.

[0010] Further, the obtaining of the flow deviation at the target time includes:

[0011] The absolute value of the difference between the flow rate data at the target time and the fitting flow rate data of the rotation speed data at the target time is taken as the flow rate deviation at the target time.

[0012] Further, obtaining the pressure fluctuation degree at the target time includes:

[0013] Obtaining a local pressure fluctuation parameter at the target time according to the difference of the pressure data of the water inlet pipe at each time within a preset time domain at the target time;

[0014] The absolute value of the difference between the pressure data of the water inlet pipe and the water outlet pipe at the target time is used as the pressure difference at the target time;

[0015] The product value of the pressure difference at the target time and the local pressure fluctuation parameter is used as the pressure fluctuation degree at the target time.

[0016] Furthermore, obtaining the local pressure fluctuation parameter at the target time according to the difference of the pressure data of the water inlet pipe at each time in the preset time domain at the target time includes:

[0017] The variance of the pressure data of the water inlet pipe at all times within a preset time domain at the target time is used as the local pressure fluctuation parameter at the target time.

[0018] Further, obtaining the pressure fluctuation constraint coefficient of the centrifugal pump includes:

[0019] The time series consisting of the flow deviations at all times is used as the first vector of the centrifugal pump; the time series consisting of the pressure fluctuation degrees at all times is used as the second vector of the centrifugal pump; the absolute value of the cosine similarity between the first vector and the second vector is used as the similarity parameter of the centrifugal pump;

[0020] The time series consisting of the flow data at all times is used as the flow data sequence, the time series consisting of the pressure data of the water inlet pipe at all times is used as the pressure data sequence, and the absolute value of the Pearson correlation coefficient between the flow data sequence and the pressure data sequence is used as the correlation parameter of the centrifugal pump;

[0021] The product value of the correlation parameter and the similarity parameter is used as the pressure fluctuation restriction coefficient of the centrifugal pump.

[0022] Further, obtaining the optimized PID controller includes:

[0023] Using the pressure fluctuation constraint coefficient of the centrifugal pump, the original objective function used by the particle swarm optimization algorithm is adjusted to obtain an adjusted objective function of the particle swarm optimization algorithm;

[0024] Utilizing the particle swarm optimization algorithm using the adjustment objective function, the PID parameter combination of the PID controller of the centrifugal pump is optimized to obtain the optimal PID parameter combination of the PID controller;

[0025] The PID controller using the optimal PID parameter combination is used as the optimized PID controller.

[0026] Furthermore, the pressure fluctuation constraint coefficient of the centrifugal pump is used to adjust the original objective function used by the particle swarm optimization algorithm to obtain the adjusted objective function of the particle swarm optimization algorithm, which includes:

[0027] The original objective function used by the particle swarm optimization algorithm is added to the pressure fluctuation constraint coefficient of the centrifugal pump to obtain the adjusted objective function of the particle swarm optimization algorithm.

[0028] Furthermore, the optimized PID controller and frequency converter based on the centrifugal pump adjust the operating frequency of the centrifugal pump, including:

[0029] The optimized PID controller is used to output a control signal to the frequency converter, and the operating frequency of the centrifugal pump is adjusted through the frequency converter.

[0030] Furthermore, obtaining the fitting flow data for each speed data includes:

[0031] Mapping the data points composed of the rotation speed data and the flow rate data at the same time into a two-dimensional coordinate system, and fitting each data point in the two-dimensional coordinate system using the least square method to obtain a fitting function, wherein the horizontal axis of the two-dimensional coordinate system represents the rotation speed data, and the vertical axis represents the flow rate data;

[0032] Each rotation speed data is input into the fitting function to obtain the fitting flow data of each rotation speed data.

[0033] The present invention also proposes a centrifugal pump module, including a frequency converter, the centrifugal pump module also includes a frequency conversion control module for controlling the frequency converter, a pressure sensor for respectively collecting pressure data of the water inlet pipe and the water outlet pipe of the centrifugal pump, a flow sensor for collecting flow data of the water outlet pipe of the centrifugal pump, and a speed sensor for collecting speed data of the pump shaft of the centrifugal pump. The frequency conversion control module samples and connects the pressure sensor, the flow sensor and the speed sensor to obtain pressure data, flow data and speed data, and processes the pressure data, flow data and speed data to implement any one of the steps of the frequency conversion operation adjustment method of the centrifugal pump module.

[0034] The present invention has the following beneficial effects:

[0035] The present invention takes into account that by using the output signal of the PID controller with fixed parameters to control the frequency converter, it is impossible to accurately adjust the working frequency of the centrifugal pump, thereby reducing the operating performance of the centrifugal pump. First, the speed data of the pump shaft of the centrifugal pump at each moment in a preset time period, the flow data of the water outlet pipe, and the pressure data of the water inlet pipe and the water outlet pipe are obtained. Subsequently, various data can be comprehensively analyzed to adjust the working frequency of the centrifugal pump and improve its operating performance. Considering that under ideal conditions, the centrifugal pump corresponds to a specific flow size at a specific speed, which is the expected flow rate at the speed, but under the influence of the interference factor of unstable water pressure in the pipeline, the water flow in the pipeline is also unstable, which causes the actual flow at a specific speed to deviate from the expected flow rate. Therefore, the data points composed of the speed data and flow data at the same time are first fitted to obtain the fitted flow data for each speed data , it is considered that the fitting flow data is the flow data expected by the speed data, and then the flow deviation is reflected under the speed data at the target time, the deviation between the actual flow and the expected flow. Considering that the main factor causing the unstable flow in the pipeline is the unstable pressure in the pipeline, the present invention analyzes the fluctuation of the local pressure data of the water inlet pipeline at the target time, and combines the pressure data difference between the water inlet pipeline and the water outlet pipeline at the target time, reflects the pressure fluctuation of the centrifugal pump pipeline at the target time through the pressure fluctuation degree, and then reflects the influence and restriction of the pressure in the pipeline on the flow through the obtained pressure fluctuation constraint coefficient, and further through the pressure fluctuation constraint coefficient, realizes adding the pressure factor of the pipeline into the optimization process of the PID controller, improves the optimization effect of the PID controller, so that the working frequency of the centrifugal pump can be accurately adjusted, the interference of pipeline pressure changes on the flow is reduced, and the operation performance of the centrifugal pump is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A flow chart of a centrifugal pump module variable frequency operation adjustment method provided by one embodiment of the present invention;

[0038] Figure 2 A flow chart of a method for obtaining the degree of pressure fluctuation at a target moment provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a centrifugal pump module and its variable frequency operation adjustment method proposed by the present invention, its specific implementation method, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0040] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0041] The specific scheme of a centrifugal pump module and its variable frequency operation adjustment method provided by the present invention is described in detail below with reference to the accompanying drawings.

[0042] See also Figure 1 , which shows a flow chart of a centrifugal pump module variable frequency operation adjustment method provided by an embodiment of the present invention, the method comprising:

[0043] Step S1: obtaining the rotation speed data of the pump shaft of the centrifugal pump, the flow data of the water outlet pipe, and the pressure data of the water inlet pipe and the water outlet pipe at each moment within a preset time period.

[0044] A centrifugal pump is a pump that uses the centrifugal force generated by the rotation of the impeller to transport liquid. In actual applications, in order to meet the needs of different working conditions, improve the operating performance of the centrifugal pump and reduce energy consumption, a centrifugal pump with a variable frequency operation function is usually used to accurately control the liquid transportation process. Therefore, the centrifugal pump, frequency converter and frequency conversion control module are usually integrated into a centrifugal pump module. The frequency conversion control module in the module outputs a control signal to the frequency converter, and the frequency converter adjusts the operating frequency of the centrifugal pump to achieve control of the speed of the centrifugal pump, thereby more accurately controlling the liquid flow in the centrifugal pump. The operating frequency of the centrifugal pump specifically refers to the power frequency of the centrifugal pump when it is working.

[0045] The embodiment of the present invention first installs a speed sensor on the pump shaft of a centrifugal pump, installs a flow sensor on the inner wall of a water outlet pipe of the centrifugal pump, and respectively installs a pressure sensor on the inner wall of a water inlet pipe and an inner wall of a water outlet pipe of the centrifugal pump, and utilizes the speed sensor, the flow sensor, and the pressure sensor to respectively collect the speed data of the pump shaft, the flow data of the water outlet pipe, and the pressure data of the water inlet pipe and the water outlet pipe of the centrifugal pump at each moment within a preset time period, wherein the preset time period is set to 2 hours, and the time intervals for collecting data from each sensor are the same, which is set to 1 minute. The preset time period and the time interval for data collection may also be set by the implementer according to the specific implementation scenario, which is not limited here.

[0046] It should be noted that the pressure sensor, flow sensor and speed sensor are all connected to the frequency conversion control module of the centrifugal pump module. In the subsequent steps, the frequency conversion control module can conduct a comprehensive analysis of various data to adjust the working frequency of the centrifugal pump and improve its operating performance.

[0047] Step S2: Fit the data points composed of the rotational speed data and the flow data at the same time to obtain the fitted flow data of each rotational speed data; take any time as the target time, and obtain the flow deviation at the target time according to the difference between the flow data at the target time and the fitted flow data of the rotational speed data at the target time; obtain the pressure fluctuation degree at the target time according to the fluctuation of the pressure data of the water inlet pipe at each time within the preset time domain of the target time, and the difference in the pressure data between the water inlet pipe and the water outlet pipe at the target time.

[0048] In order to achieve efficient operation of the centrifugal pump while reducing energy consumption, the power supply frequency of the pump is usually adjusted by a frequency converter, thereby changing the speed of the pump to control the flow rate and meet the flow rate demand. Under dynamic conditions, in order to ensure that the centrifugal pump system can supply water or transport liquid on demand to avoid excessive or insufficient conditions, the speed of the centrifugal pump is directly related to the flow rate. Therefore, it is necessary to analyze the relationship between the speed and the flow rate, and adjust the speed of the centrifugal pump according to actual needs to accurately control the output flow rate of the centrifugal pump. Ideally, the centrifugal pump corresponds to a specific flow rate at a specific speed, which is the expected flow rate at the speed. However, under the influence of interference factors such as unstable water pressure in the pipeline, the water flow rate in the pipeline is also unstable, which leads to a deviation between the actual flow rate at a specific speed and the expected flow rate. Therefore, the embodiment of the present invention first fits the data points composed of the speed data and the flow data at the same time to obtain the fitted flow data of each speed data, wherein the fitted flow data can be considered as the expected flow rate at each speed, providing a data basis for the subsequent calculation of the flow deviation at each time.

[0049] Preferably, in one embodiment of the present invention, the method for acquiring the fitting flow data of each speed data specifically includes:

[0050] The data points consisting of the speed data and flow data at the same time are mapped to a two-dimensional coordinate system, and the least squares method is used to fit each data point in the two-dimensional coordinate system to obtain a fitting function. The fitting function is the functional form of the curve that appears in the fitting. The independent variable is the speed data, and the dependent variable is the flow data. The horizontal axis of the two-dimensional coordinate system represents the speed data, and the vertical axis represents the flow data. That is to say, the first dimension data of the data point is the speed data, and the second dimension data is the flow data.

[0051] Then, each speed data is input into the fitting function, and the output result of the function is used as the fitting flow data of each speed data, wherein the least square method is a technical means well known to those skilled in the art and will not be elaborated here.

[0052] Due to the fluctuation of water pressure in the centrifugal pump pipeline, there is a certain deviation between the actual flow rate of the centrifugal pump and the expected flow rate at a specific speed. Therefore, the embodiment of the present invention first analyzes any moment, takes any moment as the target moment, and analyzes the difference between the flow data at the target moment and the fitted flow data of the speed data at the target moment. The flow deviation is reflected in the speed data at the target moment. The deviation between the actual flow rate and the expected flow rate provides a data basis for subsequently reducing the impact of unstable water pressure factors in the pipeline on the flow rate and achieving more accurate frequency conversion regulation.

[0053] Preferably, in one embodiment of the present invention, the method for obtaining the flow deviation at the target time specifically includes:

[0054] The absolute value of the difference between the flow rate data at the target time and the fitting flow rate data of the rotation speed data at the target time is taken as the flow rate deviation at the target time.

[0055] As an example, in one embodiment of the present invention, the expression of the flow deviation at the target time may be specifically, for example, as follows:

[0056]

[0057] in, Indicates the flow deviation at the target time; Indicates the traffic data at the target time; This represents the fitted flow rate data of the rotation speed data at the target time.

[0058] The flow deviation at each moment can be obtained by the same method as above.

[0059] Since the main factor causing the instability of the flow in the pipeline is the instability of the pressure in the pipeline, when the pressure in the pipeline fluctuates greatly, the centrifugal pump must overcome the pressure fluctuation in the pipeline to maintain the flow demand. The pressure fluctuation in the pipeline often directly affects the stability of the flow, thereby affecting the operating performance of the centrifugal pump. At the same time, the flow in the pipeline of the centrifugal pump is also affected by the pressure difference between the water inlet pipeline and the water outlet pipeline. Since the embodiment of the present invention has the pressure data of the water inlet pipeline and the pressure data of the water outlet pipeline, in one embodiment of the present invention, the pressure data of the water inlet pipeline is selected for fluctuation analysis, and in other embodiments of the present invention, the pressure data of the water outlet pipeline can also be selected for fluctuation analysis. The analysis is not limited here, so firstly, the fluctuation of the local pressure data of the water inlet pipe at the target time is analyzed, and combined with the difference in pressure data between the water inlet pipe and the water outlet pipe at the target time, the pressure fluctuation degree is used to reflect the pressure fluctuation of the centrifugal pump pipe at the target time. The greater the pressure fluctuation degree, the more obvious the local pressure fluctuation of the centrifugal pump pipe at the target time. Subsequently, based on the pressure fluctuation degree at each moment and the flow deviation at each moment obtained as mentioned above, the restrictive effect of pressure fluctuation on flow can be accurately analyzed, thereby realizing precise adjustment of the working frequency of the centrifugal pump, more accurate control of flow, reducing deviation, and improving the operating performance of the centrifugal pump.

[0060] Among them, the length of the preset time domain of the target moment is set to 7, that is, the preset time domain includes the target moment and the 6 other moments closest to the target moment. The specific length of the preset time domain can also be set by the implementer according to the specific implementation scenario, and is not limited here.

[0061] Preferably, in one embodiment of the present invention, the method for obtaining the pressure fluctuation degree at the target moment specifically includes:

[0062] See also Figure 2 , which shows a flow chart of a method for obtaining the pressure fluctuation degree at a target moment provided by an embodiment of the present invention.

[0063] Step S201: obtaining a local pressure fluctuation parameter at a target time according to the difference in pressure data of the water inlet pipe at each time within a preset time domain at the target time.

[0064] Since the greater the difference in pressure data at each moment of the water inlet pipe within the preset time domain of the target moment, the more obvious the fluctuation phenomenon of the pressure data of the water inlet pipe within the preset time domain of the target moment, the difference in pressure data at each moment of the water inlet pipe within the preset time domain of the target moment can be used to obtain the local pressure fluctuation parameter of the target moment. The larger the local pressure fluctuation parameter is, the greater the degree of local pressure fluctuation of the water inlet pipe at the target moment is, thereby providing a data basis for the subsequent calculation of the degree of pressure fluctuation at the target moment.

[0065] Preferably, in one embodiment of the present invention, the method for obtaining the local pressure fluctuation parameter at the target moment specifically includes:

[0066] The variance of the pressure data of the water inlet pipe at all times within the preset time domain of the target moment is used as the local pressure fluctuation parameter of the target moment. In other embodiments of the present invention, the standard deviation of the pressure data of the water inlet pipe at all times within the preset time domain of the target moment can also be used as the local pressure fluctuation parameter of the target moment, which is not limited here.

[0067] Step S202: taking the absolute value of the difference between the pressure data of the water inlet pipe and the water outlet pipe at the target time as the pressure difference at the target time.

[0068] Since the flow rate in the centrifugal pump pipeline is also affected by the pressure difference between the water inlet pipeline and the water outlet pipeline, for example, if the water inlet pipeline pressure is low and the water outlet pipeline pressure is high, the workload of the pump will increase and the flow rate will be significantly reduced. When the water inlet pipeline pressure is sufficient and the water outlet pipeline pressure is moderate, the flow rate will be relatively high and stable. Therefore, the embodiment of the present invention uses the absolute value of the difference in pressure data between the water inlet pipeline and the water outlet pipeline at the target moment as the pressure difference at the target moment. Subsequently, the pressure difference between the water inlet pipeline and the water outlet pipeline at the target moment can be added to the calculation of the pressure fluctuation degree at the target moment, thereby achieving subsequent precise control of the flow rate and improving the operating performance of the centrifugal pump.

[0069] As an example, in one embodiment of the present invention, the expression of the pressure difference at the target time may be specifically, for example, as follows:

[0070]

[0071] in, Indicates the pressure difference at the target moment; Indicates the pressure data of the water inlet pipe at the target time; Indicates the pressure data of the water outlet pipe at the target time.

[0072] Step S203: taking the product of the pressure difference at the target time and the local pressure fluctuation parameter as the pressure fluctuation degree at the target time.

[0073] The larger the local pressure fluctuation parameter and the pressure difference at the target time, the more obvious the pressure fluctuation that affects the flow stability of the centrifugal pump is. Therefore, the product of the pressure difference at the target time and the local pressure fluctuation parameter can be used as the pressure fluctuation degree at the target time.

[0074] As an example, in one embodiment of the present invention, the expression of the pressure fluctuation degree at the target time may be specifically, for example, as follows:

[0075]

[0076] in, Indicates the degree of pressure fluctuation at the target moment; Indicates the pressure difference at the target moment; It represents the variance of the pressure data of the water inlet pipe at all times within the preset time domain at the target time, that is, the local pressure fluctuation parameter at the target time.

[0077] The pressure fluctuation degree at each moment can be obtained by the same method as above.

[0078] Step S3: According to the difference in flow deviation and pressure fluctuation degree at each moment, and the correlation between flow data and pressure data at each moment, the pressure fluctuation constraint coefficient of the centrifugal pump is obtained; based on the pressure fluctuation constraint coefficient, the PID controller of the centrifugal pump is optimized to obtain an optimized PID controller.

[0079] Since the change and fluctuation of the pressure in the centrifugal pump pipeline is the main factor affecting the instability of the flow in the pipeline, in order to reduce the interference of the pressure fluctuation in the centrifugal pump pipeline on the flow through the frequency conversion regulation function, it is necessary to perform a correlation analysis on the flow deviation and the pressure fluctuation degree at each moment, so as to better understand the restriction and influence of the pressure fluctuation on the flow, and facilitate the subsequent realization of more precise control of the flow in the centrifugal pump pipeline and improve the operating performance of the centrifugal pump. Therefore, the embodiment of the present invention analyzes the differences in the flow deviation and the pressure fluctuation degree at each moment, and at the same time combines the correlation between the flow data and the pressure data at each moment, and reflects the restriction of the pressure fluctuation in the centrifugal pump pipeline on the flow through the obtained pressure fluctuation restriction coefficient. The larger the pressure fluctuation restriction coefficient, the stronger the restriction of the pressure fluctuation on the flow, and the greater the degree of flow deviation caused by the pressure fluctuation. The PID controller can be optimized based on the pressure fluctuation restriction coefficient of the centrifugal pump module, so as to more accurately control the working frequency of the centrifugal pump.

[0080] Preferably, in one embodiment of the present invention, the method for obtaining the pressure fluctuation constraint coefficient of the centrifugal pump specifically includes:

[0081] First, a time series consisting of flow deviations at all moments is taken as the first vector of the centrifugal pump; a time series consisting of pressure fluctuation degrees at all moments is taken as the second vector of the centrifugal pump; the absolute value of the cosine similarity between the first vector and the second vector is taken as the similarity parameter of the centrifugal pump. The larger the similarity parameter is, the stronger the correlation between the pressure fluctuation and the flow deviation in the centrifugal pump pipeline is, and further the stronger the restrictive effect of the pressure fluctuation on the flow deviation is. Subsequently, the pressure fluctuation restriction coefficient of the centrifugal pump can be accurately calculated based on the similarity parameter. In other embodiments of the present invention, the Euclidean distance or Manhattan distance between the first vector and the second vector can also be analyzed to calculate the similarity parameter of the centrifugal pump. For example, the Euclidean distance or Manhattan distance between the first vector and the second vector can be negatively correlated to obtain the similarity parameter of the centrifugal pump, which is not limited here.

[0082] Then, the time series composed of the flow data at all moments is taken as the flow data sequence, and the time series composed of the pressure data of the water inlet pipe at all moments is taken as the pressure data sequence. The absolute value of the Pearson correlation coefficient between the flow data sequence and the pressure data sequence is taken as the correlation parameter of the centrifugal pump. The larger the correlation parameter is, the stronger the correlation between the pressure and flow of the centrifugal pump pipeline is, and further the higher the confidence level of the similarity parameters of the centrifugal pump obtained above is. In other embodiments of the present invention, for example, the Spearman rank correlation coefficient or the Kendall rank correlation coefficient may also be used, which is not limited here.

[0083] Furthermore, the product value of the correlation parameter and the similarity parameter can be used as the pressure fluctuation constraint coefficient of the centrifugal pump, wherein the correlation parameter is used as the confidence factor to weight the similarity parameter to improve the calculation accuracy of the pressure fluctuation constraint coefficient.

[0084] As an example, in one embodiment of the present invention, the expression of the pressure fluctuation restriction coefficient of the centrifugal pump can be specifically, for example, as follows:

[0085]

[0086] in, Indicates the pressure fluctuation restriction coefficient of the centrifugal pump; represents the Pearson correlation coefficient between the flow data series and the pressure data series; Represents the correlation parameters of the centrifugal pump; and and respectively represent a first vector and a second vector of a centrifugal pump; represents the cosine similarity between the first vector and the second vector; Represents the similarity parameter of the centrifugal pump.

[0087] Usually, the frequency conversion regulation module of a centrifugal pump with frequency conversion regulation function has a built-in PID controller, and the traditional frequency conversion regulation method of a centrifugal pump is usually to output a control signal to the frequency converter by using a fixed-parameter PID controller, and control the working frequency and speed of the centrifugal pump by the frequency converter, without considering the influence of external factors such as pressure fluctuations in the centrifugal pump pipeline on the flow rate, resulting in poor regulation effect on the working frequency of the centrifugal pump, and unable to effectively improve the operating performance of the centrifugal pump. The pressure fluctuation constraint coefficient obtained above reflects the restrictive influence of pressure fluctuations in the centrifugal pump pipeline on the flow rate. Therefore, the PID controller of the centrifugal pump can be optimized based on the pressure fluctuation constraint coefficient of the centrifugal pump to obtain an optimized PID controller. Subsequently, a more accurate control signal can be output to the frequency converter by the optimized PID controller, thereby accurately adjusting the working frequency of the centrifugal pump and improving the operating performance of the centrifugal pump.

[0088] Preferably, in one embodiment of the present invention, the method for obtaining the optimized PID controller of the centrifugal pump specifically includes:

[0089] Firstly, the pressure fluctuation constraint coefficient of the centrifugal pump is used to adjust the original objective function used by the particle swarm optimization algorithm to obtain the adjusted objective function of the particle swarm optimization algorithm. Here, the pressure fluctuation constraint coefficient is used as the influencing term of the original objective function. That is to say, the pressure fluctuation constraint coefficient of the centrifugal pump is introduced into the original objective function used by the particle swarm optimization algorithm, so that the obtained adjusted objective function takes into account the restrictive influence of pressure fluctuation on flow rate, thereby realizing a more effective optimization of the PID controller in the future. The particle swarm optimization algorithm is a technical means well known to those skilled in the art and will not be elaborated here.

[0090] Preferably, in one embodiment of the present invention, the method for obtaining the adjusted objective function of the particle swarm optimization algorithm specifically includes:

[0091] The original objective function used by the particle swarm optimization algorithm is added to the pressure fluctuation constraint coefficient of the centrifugal pump to obtain the adjusted objective function of the particle swarm optimization algorithm.

[0092] As an example, in one embodiment of the present invention, the expression of the adjustment objective function of the particle swarm optimization algorithm can be specifically, for example, as follows:

[0093]

[0094] in, represents the adjusted objective function of the particle swarm optimization algorithm; Represents the original objective function used by the particle swarm optimization algorithm, which is a known function of the particle swarm optimization algorithm; Indicates the pressure fluctuation restriction coefficient of the centrifugal pump.

[0095] Then, the PID parameter combination of the PID controller of the centrifugal pump is optimized by using the particle swarm optimization algorithm with an adjusted objective function to obtain the optimal PID parameter combination of the PID controller, and then the PID controller using the optimal PID parameter combination is used as the optimized PID controller.

[0096] At this point, the optimized PID controller of the centrifugal pump has been obtained. Subsequently, the optimized PID controller can be used to output a more accurate control signal to the frequency converter of the centrifugal pump, thereby achieving precise adjustment of the operating frequency of the centrifugal pump and improving the operating performance of the centrifugal pump.

[0097] Step S4: Based on the optimized PID controller and frequency converter of the centrifugal pump, the operating frequency of the centrifugal pump is adjusted.

[0098] The optimized PID controller takes into account the influence of pressure fluctuations in the centrifugal pump pipeline when outputting control signals. Therefore, the control signal output by the optimized PID controller is more accurate. After the frequency converter receives the control signal of the optimized PID controller, it can more accurately adjust the working frequency of the centrifugal pump and more accurately control the output flow of the centrifugal pump. Therefore, based on the optimized PID controller and frequency converter of the centrifugal pump, the operating frequency of the centrifugal pump can be adjusted to improve the operating performance of the centrifugal pump.

[0099] Preferably, in one embodiment of the present invention, the method for adjusting the operating frequency of the centrifugal pump specifically includes:

[0100] The optimized PID controller is used to output a control signal to the frequency converter, and the operating frequency of the centrifugal pump is adjusted through the frequency converter. The centrifugal pump with variable frequency regulation can adjust the speed to achieve precise control of the output flow.

[0101] An embodiment of the present invention provides a centrifugal pump module, including a frequency converter, the centrifugal pump module also includes a frequency conversion control module for controlling the frequency converter, a pressure sensor for respectively collecting pressure data of an inlet pipe and an outlet pipe of the centrifugal pump, a flow sensor for collecting flow data of the outlet pipe of the centrifugal pump, and a speed sensor for collecting speed data of a pump shaft of the centrifugal pump. The frequency conversion control module samples and connects the pressure sensor, the flow sensor, and the speed sensor to obtain pressure data, flow data, and speed data, and processes the pressure data, flow data, and speed data to implement the method described in steps S1 to S4.

[0102] In summary, the embodiment of the present invention first obtains the speed data of the pump shaft, the flow data of the outlet pipe, and the pressure data of the inlet pipe and the outlet pipe of the centrifugal pump at each moment within a preset time period; fits the data points composed of the speed data and the flow data at the same moment to obtain the fitted flow data of each speed data; takes any moment as the target moment, and obtains the flow deviation at the target moment according to the difference between the flow data at the target moment and the fitted flow data of the speed data at the target moment; obtains the pressure fluctuation degree at the target moment according to the fluctuation of the pressure data of the inlet pipe at each moment within the preset time domain of the target moment, and the difference in the pressure data between the inlet pipe and the outlet pipe at the target moment; obtains the pressure fluctuation constraint coefficient of the centrifugal pump according to the difference in the flow deviation and the pressure fluctuation degree at each moment, and the correlation between the flow data and the pressure data at each moment; optimizes the PID controller of the centrifugal pump based on the pressure fluctuation constraint coefficient to obtain the optimized PID controller; adjusts the operating frequency of the centrifugal pump based on the optimized PID controller and the frequency converter of the centrifugal pump.

[0103] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0104] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A method for adjusting the frequency conversion operation of a centrifugal pump module, characterized in that: The method comprises: Obtaining the pump shaft speed data, the flow rate data of the water outlet pipe, and the pressure data of the water inlet pipe and the water outlet pipe of the centrifugal pump at each moment in a preset time period; Fitting the data points composed of the rotation speed data and the flow data at the same time to obtain the fitted flow data of each rotation speed data; taking any time as the target time, and obtaining the flow deviation at the target time according to the difference between the flow data at the target time and the fitted flow data of the rotation speed data at the target time; obtaining the pressure fluctuation degree at the target time according to the fluctuation of the pressure data at each time of the water inlet pipe within the preset time domain of the target time, and the difference of the pressure data between the water inlet pipe and the water outlet pipe at the target time; According to the difference between the flow deviation and the pressure fluctuation degree at each moment, and the correlation between the flow data and the pressure data at each moment, a pressure fluctuation constraint coefficient of the centrifugal pump is obtained; based on the pressure fluctuation constraint coefficient, a PID controller of the centrifugal pump is optimized to obtain an optimized PID controller; Based on the optimized PID controller and frequency converter of the centrifugal pump, the operating frequency of the centrifugal pump is adjusted.

2. A centrifugal pump module variable frequency operation adjustment method according to claim 1, characterized in that: The flow deviation at the target time is obtained as follows: The absolute value of the difference between the flow rate data at the target time and the fitting flow rate data of the rotation speed data at the target time is taken as the flow rate deviation at the target time.

3. A centrifugal pump module variable frequency operation adjustment method according to claim 1, characterized in that: The pressure fluctuation degree of obtaining the target time includes: Obtaining a local pressure fluctuation parameter at the target time according to the difference of the pressure data of the water inlet pipe at each time within a preset time domain at the target time; The absolute value of the difference between the pressure data of the water inlet pipe and the water outlet pipe at the target time is used as the pressure difference at the target time; The product value of the pressure difference at the target time and the local pressure fluctuation parameter is used as the pressure fluctuation degree at the target time.

4. A centrifugal pump module variable frequency operation adjustment method according to claim 3, characterized in that: The step of obtaining the local pressure fluctuation parameter at the target time according to the difference of the pressure data of the water inlet pipe at each time within the preset time domain at the target time comprises: The variance of the pressure data of the water inlet pipe at all times within a preset time domain at the target time is used as the local pressure fluctuation parameter at the target time.

5. A centrifugal pump module variable frequency operation adjustment method according to claim 1, characterized in that: The method of obtaining the pressure fluctuation restriction coefficient of the centrifugal pump comprises: The time series consisting of the flow deviations at all times is used as the first vector of the centrifugal pump; the time series consisting of the pressure fluctuation degrees at all times is used as the second vector of the centrifugal pump; the absolute value of the cosine similarity between the first vector and the second vector is used as the similarity parameter of the centrifugal pump; The time series consisting of the flow data at all times is used as the flow data sequence, the time series consisting of the pressure data of the water inlet pipe at all times is used as the pressure data sequence, and the absolute value of the Pearson correlation coefficient between the flow data sequence and the pressure data sequence is used as the correlation parameter of the centrifugal pump; The product value of the correlation parameter and the similarity parameter is used as the pressure fluctuation restriction coefficient of the centrifugal pump.

6. A centrifugal pump module variable frequency operation adjustment method according to claim 1, characterized in that: The obtaining of the optimized PID controller comprises: Using the pressure fluctuation constraint coefficient of the centrifugal pump, the original objective function used by the particle swarm optimization algorithm is adjusted to obtain an adjusted objective function of the particle swarm optimization algorithm; Utilizing the particle swarm optimization algorithm using the adjustment objective function, the PID parameter combination of the PID controller of the centrifugal pump is optimized to obtain the optimal PID parameter combination of the PID controller; The PID controller using the optimal PID parameter combination is used as the optimized PID controller.

7. A centrifugal pump module variable frequency operation adjustment method according to claim 6, characterized in that: The method of adjusting the original objective function used by the particle swarm optimization algorithm by using the pressure fluctuation constraint coefficient of the centrifugal pump to obtain the adjusted objective function of the particle swarm optimization algorithm includes: The original objective function used by the particle swarm optimization algorithm is added to the pressure fluctuation constraint coefficient of the centrifugal pump to obtain the adjusted objective function of the particle swarm optimization algorithm.

8. A centrifugal pump module variable frequency operation adjustment method according to claim 1, characterized in that: The optimized PID controller and frequency converter based on the centrifugal pump adjust the operating frequency of the centrifugal pump, including: The optimized PID controller is used to output a control signal to the frequency converter, and the operating frequency of the centrifugal pump is adjusted through the frequency converter.

9. A centrifugal pump module variable frequency operation adjustment method according to claim 1, characterized in that: The obtaining of the fitting flow data for each speed data comprises: Mapping the data points composed of the rotation speed data and the flow rate data at the same time into a two-dimensional coordinate system, and fitting each data point in the two-dimensional coordinate system using the least square method to obtain a fitting function, wherein the horizontal axis of the two-dimensional coordinate system represents the rotation speed data, and the vertical axis represents the flow rate data; Each rotation speed data is input into the fitting function to obtain the fitting flow data of each rotation speed data.

10. A centrifugal pump module, comprising a frequency converter, characterized in that: The centrifugal pump module also includes a frequency conversion control module for controlling the frequency converter, a pressure sensor for respectively collecting pressure data of the water inlet pipe and the water outlet pipe of the centrifugal pump, a flow sensor for collecting flow data of the water outlet pipe of the centrifugal pump, and a speed sensor for collecting speed data of the pump shaft of the centrifugal pump. The frequency conversion control module samples and connects the pressure sensor, flow sensor and speed sensor to obtain pressure data, flow data and speed data, and processes the pressure data, flow data and speed data to implement the steps of the method as described in any one of claims 1 to 9.

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