阅读说明：本技术 一种给水泵系统的控制方法及给水泵系统 (Control method of water feed pump system and water feed pump system ) 是由 刘卫伟 陆志勇 刘强 刘传之 于 2020-04-09 设计创作，主要内容包括：本发明公开了一种给水泵系统的控制方法,包括步骤一、建立所述给水泵系统的专有模型；步骤二、在所述变频控制器中设定一个允许频率偏差；步骤三、在水泵实际运行时,获取水泵出水端的实际流量,并计算得到此时所述给水泵系统的需求扬程；步骤四、根据水泵性能的实际流量和需求扬程代入至水泵性能模型中,得到水泵的转速,并将转速换算成变频器的计算运行频率；步骤五、所述变频控制器获取此时变频器的实际运行频率,并获得计算运行频率与实际运行频率的频率差值,比较所述频率差值与允许频率偏差,选择变频器的输出频率。本发明能够降低给水泵系统的能量消耗,另外本发明还提供了一种给水泵系统。(The invention discloses a control method of a water supply pump system, which comprises the following steps of firstly, establishing a special model of the water supply pump system; setting an allowable frequency deviation in the variable frequency controller; step three, when the water pump actually runs, acquiring the actual flow of the water outlet end of the water pump, and calculating to obtain the required lift of the water supply pump system at the moment; step four, substituting the actual flow and the required lift according to the performance of the water pump into a water pump performance model to obtain the rotating speed of the water pump, and converting the rotating speed into the calculated operating frequency of the frequency converter; and step five, the frequency conversion controller acquires the actual operating frequency of the frequency converter at the moment, acquires the frequency difference value between the calculated operating frequency and the actual operating frequency, compares the frequency difference value with the allowable frequency deviation, and selects the output frequency of the frequency converter. The invention can reduce the energy consumption of the water feeding pump system, and in addition, the invention also provides the water feeding pump system.)

1. A method of controlling a feed water pump system, comprising the steps of:

step one, testing the pump lift of a water pump and the flow of a water outlet end of the water pump when the water pump system operates, and establishing a special model of the water pump system according to the measured pump lift and flow;

fitting a test performance table of a water pump in the water feed pump system to a water pump performance model, inputting the water pump performance model into a variable frequency controller for controlling the water feed pump system, and setting an allowable frequency deviation in the variable frequency controller;

step three, when the water pump is actually operated, the frequency conversion controller obtains the actual flow of the water outlet end of the water pump, substitutes the actual flow into a special model of the water supply pump system, and calculates to obtain the required lift of the water supply pump system at the moment;

step four, the variable frequency controller is substituted into a water pump performance model according to the actual flow and the required lift of the water pump to obtain the rotating speed of the water pump, and the rotating speed is converted into the calculated operating frequency of the frequency converter;

and step five, the frequency conversion controller acquires the actual running frequency of the frequency converter at the moment, acquires the frequency difference value between the calculated running frequency and the actual running frequency, compares the frequency difference value with the allowable frequency deviation, controls the frequency converter to run according to the calculated running frequency if the frequency difference value is larger than the allowable frequency deviation, and controls the frequency converter to run according to the actual running frequency if the frequency difference value is smaller than the allowable frequency deviation.

2. The method as claimed in claim 1, wherein the step one of establishing a model specific to the feed water pump system comprises:

a. a calculation formula which accords with a pipeline characteristic curve is set in a variable frequency controller in advance: h = k × Q²+H₀Wherein k is constant, H is head, H₀The system required head is when the flow is 0;

b. after the water feeding pump system is installed, starting the water pump, and setting the output frequency of the frequency converter to be f₁And the variable frequency controller acquires the flow Q of the water outlet end of the water feeding pump system at the moment₁And the pressure difference P between the water inlet and the water outlet of the water pump₁Converting the pressure difference into a lift H₁；

c. Setting the output frequency of the frequency converter to f₂And the variable frequency controller acquires the flow Q of the water outlet end of the water feeding pump system at the moment₂And the pressure difference P between the water inlet end and the water outlet end of the water pump₂Converting the pressure difference into a lift H₂；

d. Respectively converting the flow Q obtained in the step b₁Lift H₁And the flow rate Q obtained in step c₂Sum lift Q₂Substituting into the calculation formula set in the step a to obtain k and H₀Thereby creating a proprietary model of the feedwater pump system.

3. The control method of the water pump system as claimed in claim 2, wherein the transformation formula of the pressure difference between the water inlet end and the water outlet end of the water pump and the lift is as follows: h = P/rho, wherein H is the lift, P is the pressure difference between the water inlet end and the water outlet end of the water pump, and rho is the density of liquid in the water pump.

4. The control method of the feed water pump system as claimed in claim 1, wherein the allowable frequency deviation is 1-5 Hz.

5. A water supply pump system using the control method according to any one of claims 1 to 4, comprising a water tank (1), a first pipeline (2), a water pump (3), a second pipeline (4) and a water outlet pipe (5), wherein the water tank (1) is communicated with the water pump (3) through the first pipeline (2), the water pump (3) is connected with the water outlet pipe (5) through the second pipeline (4), a first pressure sensor for detecting the pressure of the water inlet end of the water pump (3) is installed on the first pipeline (2), a second pressure sensor for detecting the pressure of the water outlet end of the water pump (3) is installed on the second pipeline (4), a flow sensor (6) is installed on the water outlet pipe (5), the water pump (3) is connected with a frequency converter (7), the frequency converter (7) is controlled by a frequency conversion controller, and the first pressure sensor, And the second pressure sensor and the flow sensor (6) are respectively connected with the variable frequency controller and transmit data to the variable frequency controller.

6. A feed pump system according to claim 5, characterised in that the first (2) and second (4) conduits are provided with control valves, respectively.

Technical Field

The invention relates to control of a water supply system pipeline, in particular to a control method of a water supply pump system and the water supply pump system.

Background

As shown in fig. 1, a bypass pipe is commonly provided in the water supply piping system to drain excess water from the system out of the system through the bypass pipe or back to the water supply source of the system. To this end, the bypass line is typically provided with a pressure or differential pressure controlled relief valve. However, from the energy consumption efficiency of the system operation, the bypass pipe is arranged to reduce the system operation efficiency and increase the energy consumption of the system operation. The excess water is returned to the water pool from the bypass after absorbing energy power from the water pump, which is energy waste. In order to reduce the energy consumption of the system, frequency conversion constant pressure control is adopted, specifically, a pressure sensor is arranged near an outlet pipeline of the pump, and the water pump runs in a frequency conversion mode. The frequency converter controller sets a pressure value, feeds back a water pump outlet pressure value signal detected by the pressure sensor to the frequency converter controller, and the frequency converter controller compares the detected numerical value with a set value, adjusts the output frequency of the frequency converter through a specific price value, and adjusts the rotating speed of the water pump, so that the pressure value at the outlet of the water pump is changed to be consistent with the set pressure. However, the flow provided by the water pump can change along with the change of the system requirement, but the pump lift is constant by the variable-frequency constant-voltage control, the higher the lift of the water pump is at the same flow, the larger the required power is, and the low efficiency of the system operation can be caused by the variable-frequency constant-voltage control.

Disclosure of Invention

In order to solve the technical problems, the invention provides a control method of a water supply pump system, which comprises the following specific steps:

step one, testing the pump lift of a water pump and the flow of a water outlet end of the water pump when the water pump system operates, and establishing a special model of the water pump system according to the measured pump lift and flow;

fitting a test performance table of a water pump in the water feed pump system to a water pump performance model, inputting the water pump performance model into a variable frequency controller for controlling the water feed pump system, and setting an allowable frequency deviation in the variable frequency controller;

step three, when the water pump is actually operated, the frequency conversion controller obtains the actual flow of the water outlet end of the water pump, substitutes the actual flow into a special model of the water supply pump system, and calculates to obtain the required lift of the water supply pump system at the moment;

step four, the variable frequency controller is substituted into a water pump performance model according to the actual flow and the required lift of the water pump to obtain the rotating speed of the water pump, and the rotating speed is converted into the calculated operating frequency of the frequency converter;

and step five, the frequency conversion controller acquires the actual running frequency of the frequency converter at the moment, acquires the frequency difference value between the calculated running frequency and the actual running frequency, compares the frequency difference value with the allowable frequency deviation, controls the frequency converter to run according to the calculated running frequency if the frequency difference value is larger than the allowable frequency deviation, and controls the frequency converter to run according to the actual running frequency if the frequency difference value is smaller than the allowable frequency deviation.

Further, the process of establishing the proprietary model of the water pump system in the first step includes:

a. a calculation formula which accords with a pipeline characteristic curve is set in a variable frequency controller in advance: h = k × Q²+H₀Wherein k is constant, H is head, H₀The system required head is when the flow is 0;

b. after the water feeding pump system is installed, starting the water pump, and setting the output frequency of the frequency converter to be f₁And the variable frequency controller acquires the flow Q of the water outlet end of the water feeding pump system at the moment₁And the pressure difference P between the water inlet and the water outlet of the water pump₁Converting the pressure difference into a lift H₁；

c. Setting the output frequency of the frequency converter to f₂And the variable frequency controller acquires the flow Q of the water outlet end of the water feeding pump system at the moment₂And the pressure difference P between the water inlet end and the water outlet end of the water pump₂Converting the pressure difference into a lift H₂；

d. Respectively converting the flow Q obtained in the step b₁Lift H₁And the flow rate Q obtained in step c₂Sum lift Q₂Substituting into the calculation formula set in the step a to obtain k and H₀Thereby creating a proprietary model of the feedwater pump system.

Further, the conversion formula of the pressure difference between the water inlet end and the water outlet end of the water pump and the lift is as follows: h = P/rho, wherein H is the lift, P is the pressure difference between the water inlet end and the water outlet end of the water pump, and rho is the density of liquid in the water pump.

Furthermore, the allowable frequency deviation is 1-5 Hz.

In addition, the invention also provides a water feeding pump system adopting the control method, which comprises a water pool, a first pipeline, a water pump, a second pipeline and a water outlet pipe, wherein the water pool is communicated with the water pump through the first pipeline, the water pump is connected with the water outlet pipe through the second pipeline, the first pipeline is provided with a first pressure sensor for detecting the pressure of the water inlet end of the water pump, the second pipeline is provided with a second pressure sensor for detecting the pressure of the water outlet end of the water pump, the water outlet pipe is provided with a flow sensor, the water pump is connected with a frequency converter, the frequency converter is controlled through a frequency conversion controller, and the first pressure sensor, the second pressure sensor and the flow sensor are respectively connected with the frequency conversion controller and transmit data to the frequency conversion controller.

Furthermore, control valves are respectively arranged on the first pipeline and the second pipeline.

Has the advantages that: 1. according to the invention, the output frequency of the frequency converter is adjusted according to the required lift under different flow conditions when the water feeding pump system operates, so that the actual operating lift of the water pump is changed when the flow is changed, and the energy consumption of the operation of the water pump is reduced;

2. the control method of the invention respectively calculates and controls according to each set of water supply pump system, realizes a customized operation mode, and optimizes the energy consumption of the water supply pump system to the maximum extent;

3. the invention monitors the change of the flow in real time in the running process, and can quickly adjust the output frequency of the frequency converter when the interior of the water supply pump system changes;

4. the invention prevents the repeated change of the output frequency of the frequency converter caused by the tiny flow change by setting the allowable frequency deviation, thereby improving the practicability.

Drawings

FIG. 1 is a schematic view of a bypass line bleed feed pump system;

FIG. 2 is a block diagram of a feedwater pump system control method of the present invention;

FIG. 3 is a schematic view of the feed water pump system of the present invention.

Reference numerals: 1-a water pool; 2-a first conduit; 3-a water pump; 4-a second conduit; 5-water outlet pipe; 6-a flow sensor; 7-frequency converter.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 2, the present invention discloses a control method for a water supply pump system, which specifically comprises:

step one, testing the pump lift of a water pump and the flow of a water outlet end of the water pump when the water pump system operates, and establishing a special model of the water pump system according to the measured pump lift and flow;

fitting a test performance table of a water pump in the water feed pump system to a water pump performance model, inputting the water pump performance model into a variable frequency controller for controlling the water feed pump system, and setting an allowable frequency deviation delta f in the variable frequency controller; and allowing the frequency deviation delta f to be 1-5 Hz, wherein the performance model is used for describing the relation between the flow, the lift and the rotating speed of the water pump.

Step three, when the water pump is actually operated, the variable frequency controller obtains the actual flow Q of the water outlet end of the water pump, substitutes the actual flow Q into a special model of the water supply pump system, and calculates to obtain the required lift H of the water supply pump system at the moment;

step four, the variable frequency controller substitutes the actual flow Q and the required lift H of the water pump into a water pump performance model to obtain the rotating speed n of the water pump, and the rotating speed n is converted into the calculated operating frequency f of the frequency converter;

and step five, the frequency conversion controller obtains the actual operation frequency ft of the frequency converter at the moment, obtains a frequency difference value between the calculated operation frequency f and the actual operation frequency ft, compares the frequency difference value delta f with an allowable frequency deviation, controls the frequency converter to operate according to the calculated operation frequency f if the frequency difference value is greater than the allowable frequency deviation, namely | f-ft | > delta f, and controls the frequency converter to operate according to the actual operation frequency ft if the frequency difference value is less than the allowable frequency deviation, namely | f-ft | < delta f.

As shown in fig. 1, when the constant-pressure variable-frequency control is adopted, since the pressure of the variable-frequency water pump is controlled at a constant value, the lift of the variable-frequency water pump is approximately equal to the pressure difference between the outlet and the inlet of the pump, and thus the lift of the variable-frequency water pump is fixed at a constant value, when the flow changes, the output frequency of the frequency converter is directly changed without changing the lift, which results in the waste of power. In the control process, firstly, a special model describing the relation between the flow rate of the water pump and the required lift is obtained according to the actual measurement of the water supply pump system, then the actual required lift at the moment is obtained through the special model after the actual flow rate is measured in the actual control process, and then the rotating speed of the water pump and the output frequency of the frequency converter are obtained according to the actual required lift. And the invention also sets allowable frequency deviation, and correspondingly selects the output frequency of the frequency converter by comparing and calculating the relationship between the frequency difference value of the operating frequency and the actual operating frequency and the allowable frequency deviation, thereby avoiding the influence of tiny flow change on the output frequency.

In this embodiment, the actual flow Q of the water outlet end of the water pump is obtained by the frequency conversion controller in the third step, and the output frequency of the frequency converter is controlled by the frequency conversion controller in the fifth step to be a cycle, and the frequency conversion controller obtains the actual flow data of the flow sensor once at regular time intervals, where the time intervals are the time of one cycle.

Further, the invention comprises a process for establishing a proprietary model of a feedwater pump system, comprising:

a. a calculation formula which accords with a pipeline characteristic curve is set in a variable frequency controller in advance: h = k × Q²+H₀Wherein k is constant, H is head, H₀The system required head is when the flow is 0;

b. after the water feeding pump system is installed, starting the water pump, and setting the output frequency of the frequency converter to be f₁And the variable frequency controller acquires the flow Q of the water outlet end of the water feeding pump system at the moment₁And the pressure difference P between the water inlet and the water outlet of the water pump₁Converting the pressure difference into a lift H₁；

c. Setting the output frequency of the frequency converter to f₂And the variable frequency controller acquires the flow Q of the water outlet end of the water feeding pump system at the moment₂And the pressure difference P between the water inlet end and the water outlet end of the water pump₂Converting the pressure difference into a lift H₂；

d. Respectively converting the flow Q obtained in the step b₁Lift H₁And the flow rate Q obtained in step c₂Sum lift Q₂Substituting into the calculation formula set in the step a to obtain k and H₀Thereby creating a proprietary model of the feedwater pump system.

The conversion formula of the pressure difference and the lift of the water inlet end and the water outlet end of the water pump is as follows: h = P/rho, wherein H is the lift, P is the pressure difference between the water inlet end and the water outlet end of the water pump, and rho is the density of liquid in the water pump.

In addition, the invention also discloses a water feeding pump system adopting the control method, which comprises a water tank 1, a first pipeline 2, a water pump 3, a second pipeline 4 and a water outlet pipe 5, wherein the water tank 1 is communicated with the water pump 3 through the first pipeline 2, the water pump 3 is connected with the water outlet pipe 5 through the second pipeline 4, a first pressure sensor for detecting the pressure of the water inlet end of the water pump 3 is installed on the first pipeline 2, a second pressure sensor for detecting the pressure of the water outlet end of the water pump 3 is installed on the second pipeline 4, a flow sensor 6 is installed on the water outlet pipe 5, the water pump 3 is connected with a frequency converter 7, the frequency converter 7 is controlled through a frequency conversion controller, and the first pressure sensor, the second pressure sensor and the flow sensor 6 are respectively connected with the frequency conversion controller and transmit data to the frequency conversion controller. Control valves are respectively arranged on the first pipeline 2 and the second pipeline 4.

The invention controls the output power of the frequency converter through the frequency conversion controller by the control method, avoids the energy loss of bypass discharge and reduces the operation energy consumption of the water pump.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.