Automatic start-stop control system and method for multiple sets of water treatment equipment

Abstract

The present application relates to the field of sewage treatment, and provides a kind of multi-set water treatment equipment automatic start-stop control method, comprising: the number of fixed frequency booster pumps needing adjustment in k period is calculated;The frequency of variable frequency booster pump in k period is calculated using BP-pid algorithm, and the weighting coefficient in k+1 period is calculated;According to the frequency of variable frequency booster pump, the running time of variable frequency booster pump and the actual liquid level of surge tank, the number of fixed frequency booster pumps needing adjustment in k period is obtained by correction to obtain accurate;The number of fixed frequency booster pumps needing operation in k period is determined.The present application not only makes up the problem of accelerated equipment wear caused by the start-stop mode of the existing technology through segmented liquid level control of booster pump, but also significantly improves the intelligent control efficiency of surge tank booster pump system.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and in particular to an automatic start-stop control system and method for multiple sets of water treatment equipment. Background Technology

[0002] Urban drainage systems are complex networks consisting of collection wells, underground pipe networks, and storage tank systems for regulating flow and controlling pollution. Storage tank systems play a crucial role in mitigating peak loads and reducing water pollution.

[0003] The regulating reservoir system includes a regulating reservoir and multiple sets of water treatment equipment. The function of the regulating reservoir is to temporarily accommodate the excess sewage or rainwater when the runoff exceeds the instantaneous treatment capacity of the underground pipe network, so as to prevent urban flooding and relieve pressure on the underground pipe network. The multiple sets of water treatment equipment are used to regulate the water level of the regulating reservoir during the water storage process. The regulation method is to use a booster pump to pump out the sewage inside the regulating reservoir to ensure that the regulating reservoir does not lose its regulating capacity due to being full.

[0004] In the traditional process of regulating the water level of a storage tank using multiple sets of water treatment equipment, it is often necessary to manually observe the liquid level of the storage tank and start and stop multiple sets of water treatment equipment in a timely manner based on experience to ensure treatment efficiency and prevent the storage tank from becoming full. However, when there is an instantaneous fluctuation in the inflow of water into the storage tank, that is, when the inflow of water into the storage tank suddenly increases or decreases, manual intervention is prone to cause a delay in the control response.

[0005] Existing patent CN117350468A achieves regulation by establishing "segmented liquid levels" in the storage tank and controlling the start and stop of the booster pumps using these segmented liquid levels. When the liquid level in the storage tank rises to a certain segment, the number of booster pumps started automatically increases, and when the liquid level in the storage tank drops, the number of booster pumps started automatically decreases. This method has significant drawbacks. For example, it requires waiting for the liquid level to rise to the designated segment before changing the number of booster pumps. If the inflow into the storage tank surges, overflow may occur due to the delayed start of the booster pumps. If the storage tank fluctuates around the critical value of a certain segmented liquid level, it will cause frequent start and stop of the equipment, accelerating equipment wear and tear. Summary of the Invention

[0006] The purpose of this invention is to improve upon the shortcomings of the existing technology and provide an automatic start-stop control system for multiple sets of water treatment equipment, including: a water pump module, a main control module, and a sensor module;

[0007] The sensor module includes a level gauge, which is used to send the measured actual level of the storage tank to the main control module.

[0008] The water pump module includes at least one set of variable frequency lift pump units and multiple sets of fixed frequency lift pump units, both of which are controlled by the main control module.

[0009] The main control module is used to calculate the rate of change of the liquid level in the storage tank based on the rated flow rate of a single booster pump and the actual liquid level data of the storage tank, and to calculate the number of fixed-frequency booster pumps that need to be adjusted based on the rate of change of the liquid level in the storage tank. It also collects the operating frequency and operating time of the variable-frequency booster pump unit in the pump module, calculates the accurate number of fixed-frequency booster pumps that need to be adjusted based on the operating frequency and operating time, and finally adjusts the number of fixed-frequency booster pumps that are turned on.

[0010] Furthermore, the variable frequency booster pump unit includes a variable frequency booster pump and a variable frequency controller. The variable frequency controller is used to control the operating frequency of the variable frequency booster pump according to the instructions of the main control module. The fixed frequency booster pump unit includes a fixed frequency booster pump and a fixed frequency controller. The fixed frequency controller is used to control the start and stop of its corresponding booster pump according to the instructions of the main control module.

[0011] Furthermore, the automatic start-stop control system for multiple sets of water treatment equipment also includes a network module, which is used to acquire local rainfall data and transmit it to the main control module.

[0012] Furthermore, the method for automatically starting and stopping multiple sets of water treatment equipment based on an automatic start-stop control system includes the following steps:

[0013] S1. Calculate the number of constant-frequency booster pumps n that need to be adjusted for k cycles based on the rated flow rate Q0 of a single booster pump, the length L and width W of the storage tank, and the actual liquid level data of the storage tank. k ;

[0014] S2. Calculate the frequency of k cycles of the variable frequency booster pump using the BP-pid algorithm. And calculate the weighting coefficients for period k+1;

[0015] S3. Based on the frequency of the variable frequency booster pump, the operating time of the variable frequency booster pump, and the actual liquid level of the storage tank, n k To obtain the accurate k-cycle, the number of fixed-frequency booster pumps that need to be adjusted. ;

[0016] S4, with Determine the number N of constant-frequency booster pumps that need to run for k cycles. (k) .

[0017] Further, step S1 specifically includes:

[0018] (1) Calculate the influence value a0 of a single booster pump on the rate of change of liquid level in the storage tank:

[0019]

[0020] Where Q0 (m 3 / h) is the rated maximum flow rate of the booster pump itself, and is the set value of the booster pump itself; L(m) is the length of the storage tank, W(m) is the width of the storage tank, and the constant 3600 is the conversion from the unit h to the unit s.

[0021] (2) Calculate the rate of change of the liquid level in the storage tank during period k. (k) :

[0022]

[0023] Where T represents the running time (s) of one cycle of the control program; h (k-2) h represents the actual liquid level (m) in the storage tank during cycle k-2. (k-1) This represents the actual liquid level (m) of the storage tank during period k-1. When k≤2, h (k-2) and h (k-1) h is 0; (k) This represents the actual liquid level (m) in the storage tank during the k-th period.

[0024] (3) Based on the influence value a0 of a single booster pump on the rate of change of the liquid level in the storage tank and the rate of change of the liquid level in the storage tank during the kth period, a (k) Calculate the number n of constant-frequency booster pumps that need to be adjusted for k cycles. k Specifically:

[0025] First, calculate the rate of change a of the liquid level in the storage tank for k periods. (k) The ratio g of the effect of a single booster pump on the rate of change of the liquid level in the storage tank to the value a0 is as follows:

[0026]

[0027] When the ratio g is greater than or equal to 0, we have:

[0028]

[0029] in This represents rounding down to the nearest integer value for g;

[0030] When the ratio g is less than 0, we have:

[0031]

[0032] in, This represents rounding up the value of g to the nearest integer.

[0033] Further, step S2 specifically includes:

[0034] A BP neural network consists of an input layer O, a hidden layer H, and an output layer L;

[0035] (1) Output of the input layer , is represented as:

[0036]

[0037]

[0038] in, This is the output of the U-th node in the input layer; U represents the index of the input layer node, and k is the periodic index. This is the input of the U-th node in the input layer, meaning the inputs of the 1st and 2nd nodes in the input layer are respectively... and , To set the liquid level r (k) (have , This is the upper limit setting value for the liquid level in the storage tank. (This can be modified according to the actual situation of the storage tank) and the actual liquid level h of the storage tank in the k-th cycle. (k) The difference ; The rate of change of the liquid level in the storage tank during the k-th cycle. ;

[0039] (2) Input of hidden layer , is represented as:

[0040]

[0041] in, This represents the input of the V-th node in the hidden layer; V represents the index of the number of nodes in the hidden layer. This represents the weighting coefficient between the Vth node of the hidden layer H and the Uth node of the input layer.

[0042] Output of hidden layer Represented as:

[0043]

[0044] in, This represents the output of the Vth node in the hidden layer; tanh(net) v,k ) indicates that net v,k Input into the tanh function.

[0045] (3) Input of output layer L , is represented as:

[0046]

[0047] in, This represents the input of the Mth node in the output layer; M represents the index of the number of nodes in the output layer. This represents the weighting coefficient between the Mth node of the output layer and the Vth node of the hidden layer.

[0048] The output of the output layer is :

[0049]

[0050] in, The output of the Mth node in the output layer is displayed. Indicates will The input is fed into the Sigmoid function;

[0051] Obtain the frequency of k cycles of the variable frequency booster pump. :

[0052] in, Let k be the frequency of the variable frequency booster pump in the kth cycle. Let k be the frequency of the (k-1)th cycle of the variable frequency booster pump. Let be the difference between the actual liquid level and the set liquid level in the storage tank during the k-th cycle. This represents the difference between the actual liquid level and the set liquid level in the storage tank during the (k-1)th cycle. Let be the difference between the actual liquid level and the set liquid level in the storage tank during the (k-2)th cycle, and ;

[0053] Step S2-2, after calculating the frequency u of the variable frequency booster pump k-cycle... (k) Then, using u (k) The weighting coefficients of the hidden layer H and the output layer L of a k+1 period BP neural network are calculated as follows:

[0054] (1) Calculate the weighting coefficients of the output layer L of the k+1 periodic BP neural network:

[0055]

[0056] in, This represents the learning rate, with a value ranging from 0.0 to 1.0. This represents the inertia coefficient, with a value ranging from 0.0 to 1.0.

[0057] (2) Calculate the weighting coefficients of the hidden layer H of the k+1 periodic BP neural network.

[0058]

[0059] in, This represents the learning rate, with a value ranging from 0.0 to 1.0. This represents the inertia coefficient, with a value ranging from 0.0 to 1.0.

[0060] Further, step S3 specifically includes:

[0061] (1) The variable frequency controller records the operating time and frequency of the variable frequency booster pump and transmits it to the main control module. When the variable frequency booster pump operates at full load frequency for more than the first time threshold, or when the actual liquid level h in the regulating tank... (k) Higher than the upper limit setting value h max If the current number of activated constant-frequency booster pumps is insufficient, then the number of constant-frequency booster pumps n that need to be adjusted for k cycles is [number missing]. k Make the following modifications:

[0062]

[0063] in, The number of fixed-frequency booster pumps that need to be adjusted for the accurate k-cycle;

[0064] (2) When the variable frequency booster pump fails to operate beyond the first time threshold, or when the actual liquid level h in the storage tank... (k) 0.1h below the lower limit of the liquid level setting. max If the number of currently activated fixed-frequency booster pumps is too large, then the number of fixed-frequency booster pumps n that need to be adjusted for k cycles is [number missing]. k Make the following modifications:

[0065]

[0066] in, The number of fixed-frequency booster pumps that need to be adjusted for the accurate k-cycle;

[0067] (3) When the operating frequency of the variable frequency booster pump and the actual liquid level h of the storage tank are... (k) If the situation does not fall under (1) and (2), it means that the number of fixed-frequency booster pumps currently in operation is just right, and there is no need to adjust the number of fixed-frequency booster pumps that need to be adjusted in k cycles. The following formula exists:

[0068]

[0069] in, This represents the number of fixed-frequency booster pumps that need to be adjusted for the accurate k-cycle.

[0070] Further, step S5 specifically involves: calculating the number N of booster pumps that need to be adjusted based on the updated number of adjustment devices and the device operating time.

[0071] (1) When When this happens, it means that period k needs to stop compared to period k-1. Given a fixed-frequency booster pump, the number of fixed-frequency booster pumps operating for k cycles can be calculated. The expression is as follows:

[0072]

[0073] in, The number of constant-frequency booster pumps operating in cycle k-1;

[0074] (2) When When this happens, it means that the k-period needs to be extended compared to the k-1-period. Given a fixed-frequency booster pump, the number of fixed-frequency booster pumps operating for k cycles can be calculated. The expression is as follows:

[0075]

[0076] in, The number of constant-frequency booster pumps operating in cycle k-1;

[0077] (3) When If the number of fixed-frequency booster pumps does not need to be changed compared to the k-1 period, then the number of fixed-frequency booster pumps operating in the k-period can be calculated. The expression is as follows:

[0078]

[0079] in, This represents the number of constant-frequency booster pumps operating in cycle k-1.

[0080] Furthermore, monitor the liquid level in the event of rainfall. The calculation method is as follows:

[0081]

[0082] in, Represents the warning level, and ; Indicates the liquid level correction factor; x represents the real-time precipitation per unit time (mm); F represents the catchment area covered by the pipe network (m²). 2N0 represents the total number of booster pumps, the value of which is determined by the actual deployment in practice; ψ represents the runoff coefficient 0.1 < ψ < 1.0; q represents the rainfall intensity (mm / h) obtained by the cloud platform; Q d Indicates the design comprehensive domestic sewage volume (m³) 3 / h); Q0 represents the rated flow rate of the booster pump (m³ / h); 3 / h); Q m Indicates the design industrial wastewater volume (m³) 3 / h); T represents the residence time of sewage in the storage tank (h); t represents the unit time 1h; ρ represents the correction coefficient.

[0083] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention constructs a regulating reservoir booster pump system by constructing multiple sets of fixed-frequency booster pump units and at least one set of variable-frequency booster pump units. It calculates the number of adjustment devices for the booster pump by utilizing the influence of a single booster pump on the booster pump and the rate of change of the regulating reservoir liquid level. The operating state of the booster pump is adjusted based on the number of adjustment devices. Furthermore, fine adjustments are made using a single variable-frequency booster pump, achieving higher liquid level control accuracy while avoiding the risk of equipment damage caused by frequent start-ups and shutdowns. Compared with traditional control schemes that rely solely on the current liquid level value for booster pump start-up and shutdown switching, this scheme uses the rate of liquid level change as the basis for regulation, achieving a faster response speed and significantly improving the intelligence level and overall operational efficiency of the regulating reservoir booster pump system. The present invention also proposes a liquid level calculation method that comprehensively considers rainfall, the catchment area of ​​the pipeline network, and the intensity of the rainstorm during rainfall, further reducing the risk of regulating reservoir overflow and the energy consumption of the booster pump during non-rainfall conditions. Attached Figure Description

[0084] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0085] Figure 1 This is a schematic diagram of an automatic start-stop control system for multiple sets of water treatment equipment involved in an embodiment of the present invention.

[0086] Figure 2 This is a schematic diagram of the water pump module of the automatic start-stop control system for multiple sets of water treatment equipment involved in the embodiments of the present invention.

[0087] Figure 3 This is a flowchart of the automatic start-stop control method for multiple sets of water treatment equipment involved in the embodiments of the present invention.

[0088] Figure 4 This is a schematic diagram of the BP-pid control structure involved in the embodiments of the present invention.

[0089] Figure 5 This is a schematic diagram of a BP network involved in an embodiment of the present invention. Detailed Implementation

[0090] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0091] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance, or suggesting any such actual relationship or order between these entities or operations. Additionally, the terms "connected," "linked," etc., can refer to a direct connection between elements or an indirect connection via other elements.

[0092] like Figure 1 As shown, the automatic start-stop control system for multiple sets of water treatment equipment includes: a water pump module, a main control module, and a sensor module.

[0093] The sensor module includes a level gauge, which in this embodiment is an ultrasonic level gauge. The ultrasonic level gauge is installed on the wall of the storage tank to measure the actual liquid level in the storage tank in real time and send the actual liquid level of the storage tank to the main control module.

[0094] The main control module is used to calculate the impact value of a single booster pump on the rate of change of the liquid level in the storage tank, the rate of change of the liquid level in the storage tank, and to calculate the number of booster pumps that need to be adjusted based on the impact value of a single booster pump on the rate of change of the liquid level in the storage tank and the rate of change of the liquid level in the storage tank.

[0095] The main control module obtains the set liquid level and sends the difference between the set liquid level and the actual liquid level in the storage tank, as well as the rate of change of the liquid level in the storage tank, to the water pump module.

[0096] like Figure 2As shown, the water pump module includes at least one set of variable frequency lift pump units and multiple sets of fixed frequency lift pump units. In this embodiment, one set of variable frequency lift pump units is used. The variable frequency lift pump unit includes a variable frequency lift pump and a variable frequency controller connected to the variable frequency lift pump. The variable frequency controller includes a variable frequency PLC controller and a BP-pid controller connected to the variable frequency PLC controller. The BP-pid controller calculates the frequency of the variable frequency lift pump based on the difference between the set liquid level and the actual liquid level in the storage tank, and the rate of change of the liquid level in the storage tank. It then controls the variable frequency lift pump to operate according to the obtained frequency. The variable frequency PLC controller acquires the operating time and frequency of the variable frequency lift pump and transmits this information to the main control module.

[0097] The fixed-frequency booster pump unit includes a fixed-frequency booster pump and a fixed-frequency controller connected to the fixed-frequency booster pump. The fixed-frequency controller is a fixed-frequency PLC controller.

[0098] After receiving the running time and frequency of the variable frequency booster pump and the actual liquid level of the storage tank, the main control module compares the data to obtain the accurate number of fixed frequency booster pumps that need to be adjusted. Finally, based on the accurate number of fixed frequency booster pumps that need to be adjusted, the module adjusts the number of fixed frequency booster pumps that need to be turned on and sends control signals to the corresponding fixed frequency PLC controller.

[0099] The fixed-frequency PLC controller is used to control the start and stop of its corresponding fixed-frequency booster pump according to the control signal sent by the main control module.

[0100] The calculation methods and control processes involved in the above embodiments will be described in detail in the subsequent embodiments of the automatic start-stop control method for multiple sets of water treatment equipment.

[0101] This system changes the operating frequency of the variable frequency lift pump, utilizing the variable frequency lift pump to handle the impact of critical liquid level fluctuations, thus preventing the fixed frequency lift pump from frequently starting and stopping during critical liquid level fluctuations.

[0102] like Figure 3 As shown, this embodiment provides an automatic start-stop control method for multiple sets of water treatment equipment, specifically including steps S1-S4:

[0103] S1. Based on the rated flow rate Q0 of a single booster pump, the length L and width W of the storage tank, and the actual liquid level of the storage tank, calculate the number n of constant-frequency booster pumps that need to be adjusted in the k-th cycle (k≥1). k The specific calculation process is as follows:

[0104] (1) Calculate the influence value a0 of a single booster pump (the variable frequency booster pump or any fixed frequency booster pump in the pump module) on the rate of change of the liquid level in the storage tank:

[0105]

[0106] Where Q0 (m 3 / h) is the rated maximum flow rate of a single booster pump, which is the set value of the booster pump itself; L(m) is the length of the storage tank, W(m) is the width of the storage tank, and the constant 3600 is the conversion from hours to seconds.

[0107] It should be noted that the single booster pump specifically refers to a variable frequency booster pump or any fixed frequency booster pump in the water pump module. In this embodiment, regardless of whether it is a variable frequency booster pump or any fixed frequency booster pump, the rated maximum flow rate is the same. It can show the effect of a booster pump operating at its rated maximum flow rate on the rate of change of the liquid level in the storage tank.

[0108] (2) Calculate the rate of change a of the liquid level in the storage tank during the k-th cycle. (k) :

[0109]

[0110] Where T represents the running time (s) of one cycle of the control program; h (k-2) h represents the actual liquid level (m) in the storage tank during the (k-2)th cycle. (k-1) This represents the actual liquid level (m) of the storage tank in the (k-1)th cycle. When k≤2, h (k-2) and h (k-1) h is 0; (k) This represents the actual liquid level (m) of the storage tank in the k-th cycle.

[0111] As an example when k=1, since k≤2, h (k-2) and h (k-1) If it is 0, then:

[0112]

[0113] As an example when k=2, since k≤2, h (k-2) and h (k-1) If it is 0, then:

[0114]

[0115] As an example when k=3, since k>2, we have:

[0116]

[0117] (3) Based on the influence value a0 of a single booster pump on the rate of change of the liquid level in the storage tank and the rate of change of the liquid level in the storage tank during the kth period, a (k) Calculate the number n of constant-frequency booster pumps that need to be adjusted in the k-th cycle.k Specifically:

[0118] First, calculate the rate of change 'a' of the liquid level in the storage tank during the k-th cycle. (k) The ratio g of the effect of a single booster pump on the rate of change of the liquid level in the storage tank to the value a0 is as follows:

[0119]

[0120] When the ratio g is greater than or equal to 0, we have:

[0121]

[0122] in This represents rounding down to the nearest integer value for g;

[0123] When the ratio g is less than 0, we have:

[0124]

[0125] in, Representative to Round the value up to the nearest integer.

[0126] As an example when the ratio g is greater than or equal to 0, suppose , Then there is Since g is greater than or equal to 0, the value of g is rounded down. .

[0127] As an example when the ratio g is less than 0, suppose , Then there is Since g is less than 0, the value of g is rounded up. .

[0128] S2. Calculate the frequency of the variable frequency booster pump using a BP-pid controller, and calculate the weighting coefficients of the hidden layer and output layer in the (k+1)th cycle.

[0129] Step S2-1, as follows Figure 4 and Figure 5 As shown, the BP-PID controller incorporates a BP neural network within a PID controller. During operation, the BP neural network receives the set liquid level r. (k) The actual liquid level h of the regulating reservoir in the kth cycle (k) The difference in liquid level e (k) and the rate of change of the liquid level in the storage tank during the kth period The output is related to K in the PID controller. p,k (proportion), K i,k (integral) and K d,kThe output value corresponding to the (differential) parameter drives the PID controller to control the variable frequency booster pump.

[0130] A BP neural network consists of an input layer O, a hidden layer H, and an output layer L. In this embodiment, there are 2 nodes in the input layer, 6 nodes in the hidden layer, and 3 nodes in the output layer. In actual use, the number of nodes in each layer of the BP neural network can be adjusted as needed.

[0131] (1) Output of the input layer Represented as:

[0132]

[0133]

[0134] in, This is the output of the U-th node in the input layer; U represents the index of the input layer node, and k is the periodic index. This is the input of the U-th node in the input layer, meaning the inputs of the 1st and 2nd nodes in the input layer are respectively... and , To set the liquid level r (k) (have , This is the upper limit setting value for the liquid level in the storage tank. (This can be modified according to the actual situation of the storage tank) and the actual liquid level h of the storage tank in the k-th cycle. (k) The difference ; The rate of change of the liquid level in the storage tank during the k-th cycle. .

[0135] (2) Input of hidden layer Represented as:

[0136]

[0137] in, This represents the input of the V-th node in the hidden layer; V represents the index of the number of nodes in the hidden layer. This represents the weighting coefficient between the Vth node of the hidden layer H and the Uth node of the input layer.

[0138] Hidden layer output Represented as:

[0139]

[0140] in, This represents the output of the Vth node in the hidden layer; tanh(net) v,k ) indicates that net v,kInput into the tanh function.

[0141] (3) Input of output layer L Represented as:

[0142]

[0143] in, This represents the input of the Mth node in the output layer; M represents the index of the number of nodes in the output layer. This represents the weighting coefficient between the Mth node of the output layer and the Vth node of the hidden layer.

[0144] The output of the output layer is :

[0145]

[0146] in, The output of the Mth node in the output layer is displayed. Indicates will The input is fed into the Sigmoid function.

[0147] It should be noted that when k=1, and The value is set automatically by the computer system. This method is existing technology and will not be elaborated here. Furthermore, the setting method is unrelated to the main idea of ​​this invention. When k>1, and The method for calculating the value is described later.

[0148] In this embodiment, the output layer of the BP neural network has three output values, namely... , and The PID controller obtains the output value of the BP neural network as its own K. p,k (proportion), K i,k (integral) and K d,k The (differential) parameter values ​​are as follows:

[0149]

[0150] Obtain the frequency of k cycles of the variable frequency booster pump. :

[0151]

[0152] in, Let k be the frequency of the variable frequency booster pump in the kth cycle. Let k be the frequency of the (k-1)th cycle of the variable frequency booster pump. Let be the difference between the actual liquid level and the set liquid level in the storage tank during the k-th cycle. This represents the difference between the actual liquid level and the set liquid level in the storage tank during the (k-1)th cycle. Let be the difference between the actual liquid level and the set liquid level in the storage tank during the (k-2)th cycle, and .

[0153] Calculate the frequency of the variable frequency booster pump in the kth cycle. Then, the variable frequency booster pump will change its own frequency to match... same.

[0154] Step S2-2, based on the frequency u of the variable frequency booster pump in the kth cycle (k) The weighting coefficients of the hidden layer H and the output layer L of the BP neural network in the (k+1)th cycle are calculated as follows:

[0155] (1) Calculate the weighting coefficients of the output layer L of the (k+1)th cycle of the BP neural network:

[0156]

[0157] in, This represents the learning rate, with a value ranging from 0.0 to 1.0. In practical applications, it needs to be adjusted according to the system. This represents the inertia coefficient, which ranges from 0.0 to 1.0 and needs to be adjusted according to the actual system.

[0158] (2) Calculate the weighting coefficients of the hidden layer H of the BP neural network in the (k+1)th cycle.

[0159]

[0160] in, This represents the learning rate, with a value ranging from 0.0 to 1.0. In practical applications, it needs to be adjusted according to the system. This represents the inertia coefficient, which ranges from 0.0 to 1.0. In practical applications, it needs to be adjusted according to the system.

[0161] It should be noted that the value calculated in step S2-2 of the k-th period is... and This will be used in step S2-1 of the (k+1)th cycle. Taking k=2 as an example, the calculation process is as follows:

[0162] (1) Output of the input layer Represented as:

[0163]

[0164] (2) Input of hidden layer Represented as:

[0165]

[0166] (3) Output of the hidden layer Represented as:

[0167]

[0168] (4) Input of output layer L Represented as:

[0169]

[0170] (5) The output of the output layer is :

[0171]

[0172] (6) Calculate the frequency u of the variable frequency booster pump in the second cycle. (2) :

[0173]

[0174] The frequency u of the second cycle of the variable frequency booster pump was calculated. (2) Then, using u (2) The weighting coefficients of the hidden layer H and the output layer L of the BP neural network in the third cycle are calculated as follows:

[0175] (1) Calculate the weighting coefficients of the output layer L of the BP neural network in the third cycle:

[0176]

[0177] in, This represents the learning rate, with a value ranging from 0.0 to 1.0. In practical applications, it needs to be adjusted according to the system. This represents the inertia coefficient, which ranges from 0.0 to 1.0 and needs to be adjusted according to the actual system.

[0178] (2) Calculate the weighting coefficients of the hidden layer H of the BP neural network in the third cycle:

[0179]

[0180] in, This represents the learning rate, with a value ranging from 0.0 to 1.0. In practical applications, it needs to be adjusted according to the system. This represents the inertia coefficient, which ranges from 0.0 to 1.0. In practical applications, it needs to be adjusted according to the system.

[0181] It's easy to understand that when k=3, we have:

[0182] (1) Output of the input layer Represented as:

[0183]

[0184] (2) Input of hidden layer Represented as:

[0185]

[0186] (3) Output of the hidden layer Represented as:

[0187]

[0188] (4) Input of output layer L Represented as:

[0189]

[0190] (5) The output of the output layer is :

[0191]

[0192] S3. Based on the frequency, operating time, and storage tank level of the variable frequency booster pump, determine the number n of fixed frequency booster pumps that need adjustment in the k-th cycle. k The correction includes the following steps:

[0193] (1) The variable frequency controller records the operating time and frequency of the variable frequency booster pump and transmits it to the main control module. When the variable frequency booster pump operates at full load for more than 600 seconds (the specific time can be adjusted according to the actual deployment) or the actual liquid level of the storage tank is h (k) Higher than the upper limit setting value h max If the current number of activated constant-frequency booster pumps is insufficient, then the number of constant-frequency booster pumps n that need to be adjusted for k cycles is [number missing]. k Make the following modifications:

[0194]

[0195] in, This represents the number of fixed-frequency booster pumps that need to be adjusted for the accurate k-cycle.

[0196] (2) When the variable frequency booster pump has not been running for more than 600 seconds (the specific time can be adjusted according to the actual deployment) or the actual liquid level of the storage tank is h (k) 0.1h below the lower limit of the liquid level setting. maxIf the number of currently activated fixed-frequency booster pumps is too large, then the number of fixed-frequency booster pumps n that need to be adjusted for k cycles is [number missing]. k Make the following modifications:

[0197]

[0198] in, This represents the number of fixed-frequency booster pumps that need to be adjusted for the accurate k-cycle.

[0199] (3) When the operating frequency of the variable frequency booster pump and the actual liquid level h of the storage tank are... (k) If the situation does not fall under (1) and (2), it means that the number of fixed-frequency booster pumps currently in operation is just right, and there is no need to adjust the number of fixed-frequency booster pumps that need to be adjusted in k cycles. The following formula exists:

[0200]

[0201] in, This represents the number of fixed-frequency booster pumps that need to be adjusted for the accurate k-cycle.

[0202] S4. The number of fixed-frequency booster pumps that need to be adjusted accurately in k cycles. Determine the number N of constant-frequency booster pumps that need to run for k cycles. (k) The adjustment process can be divided into the following three situations:

[0203] (1) When When this happens, it means that period k needs to stop compared to period k-1. Given a fixed-frequency booster pump, the number of fixed-frequency booster pumps operating for k cycles can be calculated. The expression is as follows:

[0204]

[0205] in, This represents the number of constant-frequency booster pumps operating in cycle k-1.

[0206] (2) When When this happens, it means that the k-period needs to be extended compared to the k-1-period. Given a fixed-frequency booster pump, the number of fixed-frequency booster pumps operating for k cycles can be calculated. The expression is as follows:

[0207]

[0208] in, This represents the number of constant-frequency booster pumps operating in cycle k-1.

[0209] (3) When If the number of fixed-frequency booster pumps does not need to be changed compared to the k-1 period, then the number of fixed-frequency booster pumps operating in the k-period can be calculated. The expression is as follows:

[0210]

[0211] in, This represents the number of constant-frequency booster pumps operating in cycle k-1.

[0212] In step S4, the three cases represented by (1), (2) and (3) are mutually exclusive, that is, in a given period k, only one of the three cases (1), (2) and (3) will be executed and will necessarily be executed.

[0213] In some embodiments, local real-time rainfall information is obtained by using a cloud server network API. When there is heavy rainfall, the water level in the storage tank needs to be set to r to reduce the risk of overflow. (k) Adjust to the warning level to prepare for a sudden increase in inflow. The warning level is also set for special operating conditions such as rainfall. The calculation method is as follows:

[0214]

[0215] in, Represents the warning level, and ; Indicates the liquid level correction factor; x represents the real-time precipitation per unit time (mm); F represents the catchment area covered by the pipe network (m²). 2 N0 represents the total number of booster pumps, the value of which is determined by the actual deployment in practice; ψ represents the runoff coefficient 0.1 < ψ < 1.0; q represents the rainfall intensity (mm / h) obtained by the cloud platform; Q d Indicates the design comprehensive domestic sewage volume (m³) 3 / h); Q0 represents the rated flow rate of the booster pump (m³ / h); 3 / h); Q m Indicates the design industrial wastewater volume (m³) 3 / h); T represents the residence time of sewage in the storage tank (h); t represents the unit time 1h; ρ represents the correction coefficient 0.0<ρ<30.0.

[0216] It's easy to understand that during rainfall, there can be a sudden increase in water inflow, posing a risk of overflow to the storage tank. Therefore, a liquid level r will be set. (k) Adjust to warning level Due to the warning level ≤ Set liquid level r (k)This allows the storage tank to withstand the impact of a sudden increase in influent flow, reducing the risk of overflow.

[0217] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An automatic start-stop control system for multiple sets of water treatment equipment, characterized in that, include: Water pump module, main control module, and sensor module; The sensor module includes a level gauge, which is used to send the measured actual level of the storage tank to the main control module. The water pump module includes at least one set of variable frequency lift pump units and multiple sets of fixed frequency lift pump units, both of which are controlled by the main control module. The main control module is used to calculate the rate of change of the liquid level in the storage tank based on the rated flow rate of a single booster pump and the actual liquid level data of the storage tank, and to calculate the number of fixed-frequency booster pumps that need to be adjusted based on the rate of change of the liquid level in the storage tank, specifically: (1) Calculate the influence value a0 of a single booster pump on the rate of change of liquid level in the storage tank: Where Q0 (m 3 / h) is the rated maximum flow rate of the booster pump itself, and is the set value of the booster pump itself; L(m) is the length of the storage tank, W(m) is the width of the storage tank, and the constant 3600 is the conversion from the unit h to the unit s; (2) Calculate the rate of change of the liquid level in the storage tank during period k, a (k) : Where T` represents the running time (s) of one cycle of the control program; h (k-2) h represents the actual liquid level (m) in the storage tank during cycle k-2. (k-1) This represents the actual liquid level (m) of the storage tank during period k-1. When k≤2, h (k-2) and h (k-1) h is 0; (k) This represents the actual liquid level (m) of the storage tank in the kth period; (3) Based on the influence value a0 of a single booster pump on the rate of change of the liquid level in the storage tank and the rate of change of the liquid level in the storage tank during the kth period, a (k) Calculate the number n of constant-frequency booster pumps that need to be adjusted for k cycles. k Specifically: First, calculate the rate of change a of the liquid level in the storage tank for k periods. (k) The ratio g of the effect of a single booster pump on the rate of change of the liquid level in the storage tank to the value a0 is as follows: When the ratio g is greater than or equal to 0, we have: in This represents rounding down to the nearest integer value for g; When the ratio g is less than 0, we have: in, This represents rounding up the value of g to the nearest integer. Furthermore, the operating frequency and operating time of the variable frequency booster pump unit in the water pump module are collected, and the accurate number of fixed frequency booster pumps that need to be adjusted is calculated based on the operating frequency and operating time. Finally, the number of fixed frequency booster pumps that are turned on is adjusted.

2. The automatic start-stop control system for multiple sets of water treatment equipment according to claim 1, characterized in that, The variable frequency booster pump unit includes a variable frequency booster pump and a variable frequency controller. The variable frequency controller is used to control the operating frequency of the variable frequency booster pump according to the instructions of the main control module. The fixed frequency booster pump unit includes a fixed frequency booster pump and a fixed frequency controller. The fixed frequency controller is used to control the start and stop of its corresponding booster pump according to the instructions of the main control module.

3. The automatic start-stop control system for multiple sets of water treatment equipment according to claim 1, characterized in that, It also includes a network module, which is used to acquire local rainfall data and transmit it to the main control module.

4. An automatic start-stop control method for multiple sets of water treatment equipment, implemented based on the automatic start-stop control system for multiple sets of water treatment equipment as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Calculate the number of constant-frequency booster pumps n that need to be adjusted for k cycles based on the rated flow rate Q0 of a single booster pump, the length L and width W of the storage tank, and the actual liquid level data of the storage tank. k ; Specifically, S1 is: (1) Calculate the influence value a0 of a single booster pump on the rate of change of liquid level in the storage tank: Where Q0 (m 3 / h) is the rated maximum flow rate of the booster pump itself, and is the set value of the booster pump itself; L(m) is the length of the storage tank, W(m) is the width of the storage tank, and the constant 3600 is the conversion from the unit h to the unit s; (2) Calculate the rate of change of the liquid level in the storage tank during period k, a (k) : Where T` represents the running time (s) of one cycle of the control program; h (k-2) h represents the actual liquid level (m) in the storage tank during cycle k-2. (k-1) This represents the actual liquid level (m) of the storage tank during period k-1. When k≤2, h (k-2) and h (k-1) h is 0; (k) This represents the actual liquid level (m) of the storage tank in the kth period; (3) Based on the influence value a0 of a single booster pump on the rate of change of the liquid level in the storage tank and the rate of change of the liquid level in the storage tank during the kth period, a (k) Calculate the number n of constant-frequency booster pumps that need to be adjusted for k cycles. k Specifically: First, calculate the rate of change a of the liquid level in the storage tank for k periods. (k) The ratio g of the effect of a single booster pump on the rate of change of the liquid level in the storage tank to the value a0 is as follows: When the ratio g is greater than or equal to 0, we have: in This represents rounding down to the nearest integer value for g; When the ratio g is less than 0, we have: in, This represents rounding up the value of g to the nearest integer. S2. Calculate the frequency of k cycles of the variable frequency booster pump using the BP-PID algorithm. And calculate the weighting coefficients for period k+1; S3. Based on the frequency of the variable frequency booster pump, the operating time of the variable frequency booster pump, and the actual liquid level of the storage tank, n k To obtain the accurate k-cycle, the number of fixed-frequency booster pumps that need to be adjusted. ; S4, with Determine the number N of constant-frequency booster pumps that need to run for k cycles. (k) .

5. The automatic start-stop control method for multiple sets of water treatment equipment according to claim 4, characterized in that, Specifically, S2 is: A BP neural network consists of an input layer O, a hidden layer H, and an output layer L; (1) Output of the input layer , is represented as: in, This is the output of the U-th node in the input layer; U represents the index of the input layer node, and k is the periodic index. This is the input of the U-th node in the input layer, meaning the inputs of the 1st and 2nd nodes in the input layer are respectively... and , To set the liquid level r (k) The actual liquid level h of the storage tank in the kth cycle (k) The difference ; The rate of change of the liquid level in the storage tank during the k-th cycle. ; (2) Input of hidden layer , is represented as: in, This represents the input of the V-th node in the hidden layer; V represents the index of the number of nodes in the hidden layer. This represents the weighting coefficient between the V-th node of the hidden layer H and the U-th node of the input layer; Output of hidden layer Represented as: in, This represents the output of the Vth node in the hidden layer; tanh(net) v,k ) indicates that net v,k Input into the tanh function; (3) Input of output layer L , is represented as: in, This represents the input of the Mth node in the output layer; M represents the index of the number of nodes in the output layer. This represents the weighting coefficient between the Mth node of the output layer and the Vth node of the hidden layer; The output of the output layer is : in, The output of the Mth node in the output layer is displayed. Indicates will Input into the Sigmoid function; Obtain the frequency of k cycles of the variable frequency booster pump. : in, Let k be the frequency of the variable frequency booster pump in the kth cycle. Let k be the frequency of the (k-1)th cycle of the variable frequency booster pump. Let be the difference between the actual liquid level and the set liquid level in the storage tank during the k-th cycle. This represents the difference between the actual liquid level and the set liquid level in the storage tank during the (k-1)th cycle. Let be the difference between the actual liquid level and the set liquid level in the storage tank during the (k-2)th cycle, and ; Step S2-2, after calculating the frequency u of the variable frequency booster pump k-cycle... (k) Then, using u (k) The weighting coefficients of the hidden layer H and the output layer L of a k+1 period BP neural network are calculated as follows: (1) Calculate the weighting coefficients of the output layer L of the k+1 periodic BP neural network: in, This represents the learning rate, with a value ranging from 0.0 to 1.

0. This represents the inertia coefficient, with a value ranging from 0.0 to 1.

0. (2) Calculate the weighting coefficients of the hidden layer H of the k+1 periodic BP neural network. in, This represents the learning rate, with a value ranging from 0.0 to 1.

0. This represents the inertia coefficient, with a value ranging from 0.0 to 1.

0.

6. The automatic start-stop control method for multiple sets of water treatment equipment according to claim 5, characterized in that, Specifically, S3 is: (1) The variable frequency controller records the operating time and frequency of the variable frequency booster pump and transmits it to the main control module. When the variable frequency booster pump operates at full load frequency for more than the first time threshold, or when the actual liquid level h in the regulating tank... (k) Higher than the upper limit setting value h max If the current number of activated constant-frequency booster pumps is insufficient, then the number of constant-frequency booster pumps n that need to be adjusted for k cycles is [number missing]. k Make the following modifications: in, The number of fixed-frequency booster pumps that need to be adjusted for the accurate k-cycle; (2) When the variable frequency booster pump fails to operate beyond the first time threshold, or when the actual liquid level h in the storage tank... (k) 0.1h below the lower limit of the liquid level setting. max If the number of currently activated fixed-frequency booster pumps is too large, then the number of fixed-frequency booster pumps n that need to be adjusted for k cycles is [number missing]. k Make the following modifications: in, The number of fixed-frequency booster pumps that need to be adjusted for the accurate k-cycle; (3) When the operating frequency of the variable frequency booster pump and the actual liquid level h of the storage tank are... (k) If neither (1) nor (2) applies, it means that the number of fixed-frequency booster pumps currently in operation is just right, and there is no need to adjust the number of fixed-frequency booster pumps that need to be adjusted in k cycles. The following formula exists: in, This represents the number of fixed-frequency booster pumps that need to be adjusted for the accurate k-cycle.

7. The automatic start-stop control method for multiple sets of water treatment equipment according to claim 6, characterized in that, This also includes S5, specifically: calculating the number N of booster pumps that need to be adjusted based on the updated number of adjusted equipment and equipment operating time. (1) When When this happens, it means that period k needs to stop compared to period k-1. Given a fixed-frequency booster pump, calculate the number of fixed-frequency booster pumps that operate for k cycles. The expression is as follows: in, The number of constant-frequency booster pumps operating in cycle k-1; (2) When When this happens, it means that the k-period needs to be extended compared to the k-1-period. Given a fixed-frequency booster pump, calculate the number of fixed-frequency booster pumps that operate for k cycles. The expression is as follows: in, The number of constant-frequency booster pumps operating in cycle k-1; (3) When If the number of fixed-frequency booster pumps does not need to be changed compared to the k-1 period, then the number of fixed-frequency booster pumps operating in the k period can be calculated. The expression is as follows: in, This represents the number of fixed-frequency booster pumps operating in cycle k-1.

8. The automatic start-stop control method for multiple sets of water treatment equipment according to any one of claims 4-7, characterized in that, Warning of water level in case of rainfall The calculation method is as follows: in, Represents the warning level, and ; Indicates the liquid level correction factor; x represents the real-time precipitation per unit time (mm); F represents the catchment area covered by the pipe network (m²). 2 N0 represents the total number of booster pumps, the value of which is determined by the actual deployment in practice; ψ represents the runoff coefficient 0.1 < ψ < 1.0; q represents the rainfall intensity (mm / h) obtained by the cloud platform; Q d Indicates the design total domestic sewage volume (m³) 3 / h); Q0 represents the rated flow rate of the booster pump (m³ / h); 3 / h); Q m Indicates the design industrial wastewater volume (m³) 3 / h); T represents the residence time of sewage in the storage tank (h); t represents the unit time 1h; ρ represents the correction coefficient.

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