CN114810565A - Full-variable-frequency constant-pressure water supply control system and control method - Google Patents
Full-variable-frequency constant-pressure water supply control system and control method Download PDFInfo
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 274
- 238000000034 method Methods 0.000 title claims description 45
- 238000006243 chemical reaction Methods 0.000 claims abstract description 26
- 230000001105 regulatory effect Effects 0.000 claims abstract description 4
- 230000009467 reduction Effects 0.000 claims description 10
- 238000004891 communication Methods 0.000 claims description 7
- 238000005086 pumping Methods 0.000 claims description 5
- 230000009471 action Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 5
- 238000005265 energy consumption Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 210000001503 joint Anatomy 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 239000008400 supply water Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/06—Control using electricity
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- E—FIXED CONSTRUCTIONS
- E03—WATER SUPPLY; SEWERAGE
- E03B—INSTALLATIONS OR METHODS FOR OBTAINING, COLLECTING, OR DISTRIBUTING WATER
- E03B11/00—Arrangements or adaptations of tanks for water supply
- E03B11/10—Arrangements or adaptations of tanks for water supply for public or like main water supply
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/02—Stopping, starting, unloading or idling control
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/10—Other safety measures
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/20—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by changing the driving speed
Abstract
The application provides a full frequency conversion constant voltage water supply control system, including water pump group (1) and converter group (2): the water pump sets (1) respectively correspond to the frequency converter sets (2); the frequency converter group (2): the pressure regulator is used for regulating the real-time pressure of the water pump set (1); full frequency conversion constant voltage water supply control system still includes: logic controller (4): is used for reading the operation data of the frequency converter group (2). The system detects the outlet pressure through a pressure sensor, compares the detected value with a set value, and determines the number of water pumps and the output frequency of a frequency converter so as to realize the purpose of constant-pressure water supply; is highly automated.
Description
Technical Field
The application relates to the field of water supply systems, in particular to the technical field of a full-variable-frequency constant-pressure water supply control system and a control method.
Background
At present, the existing frequency conversion constant-pressure water supply system generally adopts one frequency converter to control a plurality of water pumps to supply water in a circulating constant-pressure manner, which is called as 'one control more' for short, and the electrical technology of the system is quite mature.
The control method comprises the following steps: after the equipment is started, one main pump operates in a down-conversion mode under the control of a frequency converter, and when the water supply pressure reaches a set value and the flow rate and the water quantity are balanced, a water pump motor is stabilized at a certain rotating speed. When the water consumption increases, the water pump will accelerate to another stable rotation speed according to the speed set by the frequency converter. When the frequency conversion water pump reaches the maximum rotating speed and the water consumption is still increased, the frequency conversion pump is switched to the power frequency operation by the system, and then the frequency converter is switched to the other main pump for frequency conversion operation. And circulating the process until the water supply pressure is met.
When the frequency conversion water pump reduces the water pump rotating speed because of the reduction of the water consumption, the water consumption is further reduced, and the system closes one power frequency pump. Until one variable frequency pump is operated. When no one uses water, the system automatically enters a sleep state. When the system pressure drops to the wake-up pressure, the water pump is automatically put into operation.
The foregoing disadvantages of a multi-control system are:
(a) impact on device lifetime: when the motor is loaded with the water pump, the water pump is rapidly stopped under the action of water pressure at the moment of switching, so that a huge water hammer effect is generated, and the impact is caused on the water pump; and when the water pump is damaged, high water pressure is superposed with counter potential of the stator, and the motor can bear impact current more than 10 times of rated current, so that the service life of the motor is influenced.
(b) Influence on effluent pressure; when increasing or reducing the power frequency pump, the smooth transition can't be accomplished to the water supply pressure of above-mentioned system (i.e. prior art), when increasing the power frequency pump, can inevitably lead to the fact the impact to water supply pressure.
(c) Impact on water safety: because the system only has one frequency converter, if the frequency converter breaks down, the water safety is affected if the normal water supply is recovered on site for more than 3 days.
(d) Impact on energy consumption: when the pump is added or reduced, the system can cause the fluctuation of the system pressure, thereby reducing the operation efficiency of the pump set and increasing the energy consumption.
In order to solve the above problems, a full frequency conversion constant pressure water supply control system and a control method are needed.
Disclosure of Invention
The application discloses full frequency conversion constant voltage water supply control system includes water pump group and converter group:
the water pump groups respectively correspond to the frequency converter groups;
the frequency converter group: the pressure regulator is used for regulating the real-time pressure of the water pump set;
full frequency conversion constant voltage water supply control system still includes:
the logic controller: and the device is used for reading the operation data of the frequency converter group.
In a preferred example, the preset parameters include a wake-up pressure, a preset pressure value, a pumping delay, a transition time, a pump reduction frequency, a sleep delay time, a preset time, a proportional time and an integral time; the operation data comprises operation rotating speed, operation frequency, operation time, operation current and operation voltage; the real-time data comprises real-time pressure, real-time temperature and real-time flow; the proportional time is the P value, and the integral time is the I value.
Full frequency constant voltage water supply control system still includes:
a touch screen: the system comprises a full-variable-frequency constant-pressure water supply control system, a frequency converter, a frequency;
field instrument: the system is used for acquiring real-time data of the full-variable-frequency constant-pressure water supply control system and transmitting the real-time data to the logic controller;
the touch screen is also used for displaying the running states and the running data of the number of the water pump sets and the frequency converter sets.
The application also discloses a control method of the full-variable-frequency constant-pressure water supply control system, which comprises the following steps:
the full-variable-frequency constant-pressure water supply control system comprises a water pump set, a frequency converter set and a logic controller; the frequency converter group can control the water pump group; the frequency converter group is in communication connection with the logic controller;
the control method comprises the following steps:
the logic controller reads system real-time data and preset parameters; the logic controller compares the real-time data of the system with preset parameters, calculates the operating frequency and outputs the operating frequency to the frequency converter group; and the frequency converter group controls the operation of the water pump group according to the operation frequency.
In a preferred embodiment, the method is characterized in that:
the full-frequency constant-pressure water supply control system also comprises a touch screen; the touch screen is in communication connection with the logic controller;
the control method further comprises the following steps:
the logic controller reads the operation data of the water pump set and the operation data of the frequency converter set and sends the operation data to the touch screen for display;
the preset parameters are set through the touch screen.
In a preferred embodiment, the control method comprises a system starting mode;
when the full variable frequency constant pressure water supply control system is started, entering a system starting mode;
in a system start-up mode:
any set water pump in the water pump group is accessed in a frequency conversion mode and is soft started through a corresponding frequency converter in the frequency converter group; the logic controller calculates and adjusts the operating frequency of all frequency converters in the frequency converter group in a unified manner, and further controls the rotating speed of all water pumps in the water pump group, so that the pressure of a pipe network is kept constant.
In a preferred embodiment, a first control mode is included;
the preset parameters comprise preset pressure and pumping delay time, and the preset pressure is a pressure value or a pressure range; the system real-time data comprises real-time pressure;
when the real-time pressure is smaller than the preset pressure, entering a first control mode;
in the first control mode:
the logic controller adjusts the rotating speed of the water pump in a working state in the water pump group through the frequency converter group so as to increase the real-time pressure until the real-time pressure is equal to the preset pressure or the real-time pressure is in the preset pressure range;
the logic controller judges at a first judgment time node:
if the real-time pressure is equal to the preset pressure or the real-time pressure is within the preset pressure range, continuously operating the frequency converter group and the water pump group according to a set mode;
if the real-time pressure is smaller than the preset pressure, continuously judging whether a water pump in an unoperated state exists in the water pump set: if not, continuing to operate the frequency converter group and the water pump group according to a set mode; if the frequency converter exists, adding a water pump, wherein the operating frequency of the frequency converter corresponding to the newly added water pump is the same as the operating frequency of the frequency converter corresponding to the water pump in the working state, and meanwhile, updating the initial time point of the first judgment time node to be the operating time point of the newly added water pump by the logic controller;
the first judgment time node is a corresponding time point after the pump delay time from the initial time point; the starting point in time is by default the point in time of entering the first control mode.
In a preferred embodiment, the method further comprises a second control mode;
the preset parameters comprise preset pressure and pump reduction frequency, and the preset pressure is a pressure value or a pressure range; the system real-time data comprises real-time pressure;
when the real-time pressure is greater than the preset pressure, entering a second control mode;
in a second control mode:
the logic controller adjusts the rotating speed of the water pump in a working state in the water pump group through the frequency converter group so as to reduce the real-time pressure until the real-time pressure is equal to the preset pressure or the real-time pressure is in the preset pressure range;
the logic controller judges at a second judgment time node:
if the current real-time pressure is not greater than the preset pressure, continuing to operate the frequency converter group and the water pump group according to a set mode;
if the current real-time pressure is larger than the preset pressure, stopping the water pump started firstly, and meanwhile, updating the starting time point of the second judgment time node to be the stopping time point of the newly stopped water pump by the logic controller;
and the second judgment time node is a time point from the starting time point, the operating frequency of the frequency converter group is less than or equal to the pump reduction frequency for the first time, and the number of the water pumps in the working state in the water pump group is more than 1.
In a preferred embodiment, a third control mode is also included;
the preset parameters comprise preset pressure, sleep frequency, sleep delay and awakening pressure, and the preset pressure is a pressure value or a pressure range; the system real-time data comprises real-time pressure; when the full-variable-frequency constant-pressure water supply control system simultaneously meets the first condition, the second condition and the third condition, entering a third control mode;
the first condition is that one and only one water pump in the water pump group is in a working state;
the second condition is that the real-time pressure is greater than the preset pressure;
the third condition is that the running frequency of a frequency converter corresponding to the water pump in the working state is less than the sleep frequency, and the duration time of the state that the running frequency is less than the sleep frequency is greater than the sleep delay;
in a third control mode:
the logic controller stops the operation of the water pump in the water pump set, and the full variable frequency constant pressure water supply control system enters a sleep state;
when the full-variable-frequency constant-pressure water supply control system simultaneously meets a fourth condition and a fifth condition, entering a system starting mode;
the fourth condition is that the full variable frequency constant pressure water supply control system is in a sleep state;
the fifth condition is that the real-time pressure is less than or equal to the wake-up pressure.
In a preferred example, the starting weight of each water pump in the water pump group is inversely proportional to the running time; and each water pump in the water pump set determines a starting sequence according to the starting weight, namely the longer the running time of the water pump is, the later the starting sequence is.
In a preferred embodiment, a fourth control mode is further included;
entering a fourth control mode when any one or more of the plurality of water pump groups fails;
in a fourth control mode:
and eliminating any one or more water pumps which have failed in the water pump group.
Compared with the prior art, the full-variable-frequency constant-pressure water supply control system and the control method have the following beneficial effects:
1. the system detects the outlet pressure through a pressure sensor, compares the detected value with a set value, and determines the number of water pumps and the output frequency of a frequency converter so as to realize the purpose of constant-pressure water supply;
2. high automation: the system realizes full-automatic control, a logic controller, a human-computer interface and the like are standardized, the running state and parameters of the water pump can be displayed on the touch screen in real time, the real-time running state of the equipment is simulated in a configuration picture and curve mode, and the running parameters and fault information can be recorded and inquired, so that the system is more intelligent.
3. Energy conservation: the frequency of a plurality of variable frequency water pumps is uniformly adjusted, the efficiency under the operation condition is balanced, no matter how the operation condition of the system changes, the water pumps always operate in a high-efficiency area, the phenomenon of energy consumption waste can not occur, and a more ideal energy-saving effect is achieved.
4. Prevent the generation of water hammer: the system is operated in a full frequency conversion mode, seamless butt joint and stable transition are realized in the switching process of the addition pump and the subtraction pump, huge impact on a water pump and a pipe network caused by instant stop is avoided, and the safety of the pipe network is ensured;
5. ensuring the water safety: when one or more frequency converters or pumps of the system have faults, the system automatically skips the fault pump to form a new system, so that normal water supply on site is ensured;
6. meanwhile, the system further comprises: the functions of idle running prevention, freezing prevention of temperature signals, automatic reset after power failure, fault alarm and the like are achieved according to the water level signals.
The present specification describes a number of technical features distributed throughout the various technical aspects, and if all possible combinations of technical features (i.e. technical aspects) of the present specification are listed, the description is made excessively long. In order to avoid this problem, the respective technical features disclosed in the above summary of the invention of the present application, the respective technical features disclosed in the following embodiments and examples, and the respective technical features disclosed in the drawings may be freely combined with each other to constitute various new technical solutions (which should be regarded as having been described in the present specification) unless such a combination of the technical features is technically infeasible. For example, in one example, the feature a + B + C is disclosed, in another example, the feature a + B + D + E is disclosed, and the features C and D are equivalent technical means for the same purpose, and technically only one feature is used, but not simultaneously employed, and the feature E can be technically combined with the feature C, then the solution of a + B + C + D should not be considered as being described because the technology is not feasible, and the solution of a + B + C + E should be considered as being described.
Drawings
Fig. 1 is a schematic diagram of a full-variable-frequency constant-pressure water supply control system and a control method provided by the present application.
Fig. 2 is a schematic diagram of a full-variable-frequency constant-pressure water supply control system and a control method provided by the present application.
Fig. 3 is a schematic diagram of a full-variable-frequency constant-pressure water supply control system and a control method provided by the present application.
Fig. 4 is a schematic structural diagram of a full-frequency-conversion constant-pressure water supply control system and a control method provided by the present application.
Reference numerals
1. Water pump set
2. Frequency converter group
3. Touch screen
4. Logic controller
Detailed Description
In the following description, numerous technical details are set forth in order to provide a better understanding of the present application. However, it will be understood by those skilled in the art that the technical solutions claimed in the present application may be implemented without these technical details and with various changes and modifications based on the following embodiments.
The application discloses full frequency conversion constant voltage water supply control system, including water pump group 1 and converter group 2: the water pump sets 1 respectively correspond to the frequency converter sets 2; the frequency converter group 2: used for adjusting the real-time pressure of the water pump set 1; full frequency conversion constant voltage water supply control system still includes: the logic controller 4: for reading the operating data of the group of frequency converters 2.
The preset parameters comprise awakening pressure, a preset pressure value, pumping delay, conversion time, pump reduction frequency, sleep delay time, preset time, a P value and an I value; the operation data comprises operation rotating speed, operation frequency, operation time, operation current and operation voltage; the real-time data comprises real-time pressure, real-time temperature and real-time flow; full frequency constant voltage water supply control system still includes: the touch screen 3: the system comprises a full-variable-frequency constant-pressure water supply control system, a frequency converter, a frequency; the field instrument 5: the system is used for collecting the real-time data of the full-variable-frequency constant-pressure water supply control system and transmitting the real-time data to the logic controller 4; the touch screen 3 is also used for displaying the running states and the running data of the number of the water pump sets 1 and the frequency converter sets 2.
The application also discloses a control method of the full-variable-frequency constant-pressure water supply control system, wherein the full-variable-frequency constant-pressure water supply control system comprises a water pump set 1, a frequency converter set 2 and a logic controller 4; the frequency converter group 2 can control the water pump group 1; the frequency converter group 2 is in communication connection with a logic controller 4;
the control method comprises the following steps:
the logic controller 4 reads system real-time data and preset parameters; the logic controller 4 compares the real-time data of the system with preset parameters, calculates the operating frequency and outputs the operating frequency to the frequency converter group 2; the frequency converter group 2 controls the operation of the water pump group 1 according to the operation frequency.
The full-frequency constant-pressure water supply control system also comprises a touch screen 3; the touch screen 3 is in communication connection with the logic controller 4; the control method further comprises the following steps: the logic controller 4 reads the operation data of the water pump set 1 and the operation data of the frequency converter set 2 and sends the operation data to the touch screen 3 for display; the preset parameters are set through the touch screen 3.
The control method comprises a system starting mode; when the full variable frequency constant pressure water supply control system is started, entering a system starting mode; in a system start-up mode: any set water pump in the water pump group 1 is accessed in a frequency conversion mode and is soft started through a corresponding frequency converter in the frequency converter group 2; the logic controller 4 calculates and adjusts the operating frequency of all the frequency converters in the frequency converter group 2 in a unified manner, and further controls the rotating speed of all the water pumps in the water pump group 1, so that the pressure of a pipe network is kept constant.
The control method provided by the application comprises a first control mode; the preset parameters comprise preset pressure and pumping delay time, and the preset pressure is a pressure value or a pressure range; the system real-time data comprises real-time pressure; when the real-time pressure is smaller than the preset pressure, entering a first control mode; in the first control mode: the logic controller 4 adjusts the rotating speed of the water pump in the working state in the water pump set 1 through the frequency converter set 2 to increase the real-time pressure until the real-time pressure is equal to the preset pressure or the real-time pressure is within the preset pressure range; the logic controller 4 judges at a first judgment time node: if the real-time pressure is equal to the preset pressure or the real-time pressure is within the preset pressure range, the frequency converter group 2 and the water pump group 1 continue to operate according to a set mode; if the real-time pressure is smaller than the preset pressure, whether a water pump in an unoperated state exists in the water pump set 1 is continuously judged: if the frequency converter group 2 and the water pump group 1 do not exist, the frequency converter group 2 and the water pump group 1 are continuously operated according to a set mode; if the frequency converter exists, adding a water pump, wherein the operating frequency of the frequency converter corresponding to the newly added water pump is the same as the operating frequency of the frequency converter corresponding to the water pump in the working state, and meanwhile, updating the starting time point of the first judgment time node to be the operating time point of the newly added water pump by the logic controller 4; the first judgment time node is a corresponding time point after the pump delay time from the initial time point; the starting point in time is by default the point in time of entering the first control mode.
The control method provided by the application further comprises a second control mode; the preset parameters comprise preset pressure and pump reduction frequency, and the preset pressure is a pressure value or a pressure range; the system real-time data comprises real-time pressure; when the real-time pressure is greater than the preset pressure, entering a second control mode; in a second control mode: the logic controller 4 adjusts the rotating speed of the water pump in the working state in the water pump group 1 through the frequency converter group 2 so as to reduce the real-time pressure until the real-time pressure is equal to the preset pressure or the real-time pressure is in the preset pressure range; the logic controller 4 makes a judgment at a second judgment time node: if the current real-time pressure is not greater than the preset pressure, continuing to operate the frequency converter group 2 and the water pump group 1 according to a set mode; if the current real-time pressure is greater than the preset pressure, stopping the water pump started firstly, and meanwhile, updating the starting time point of the second judgment time node to be the stopping time point of the newly stopped water pump by the logic controller 4; the second judgment time node is a time point when the operating frequency of the frequency converter group 2 is less than or equal to the pump reduction frequency for the first time from the starting time point and the number of the water pumps in the working state in the water pump group 1 is greater than 1.
The control method provided by the application further comprises a third control mode; the preset parameters comprise preset pressure, sleep frequency, sleep delay and awakening pressure, and the preset pressure is a pressure value or a pressure range; the system real-time data comprises real-time pressure; when the full-variable-frequency constant-pressure water supply control system simultaneously meets the first condition, the second condition and the third condition, entering a third control mode; the first condition is that one and only one water pump in the water pump group 1 is in a working state; the second condition is that the real-time pressure is greater than the preset pressure; the third condition is that the running frequency of a frequency converter corresponding to the water pump in the working state is less than the sleep frequency, and the duration of the state that the running frequency is less than the sleep frequency is longer than the sleep delay; in a third control mode: the logic controller 4 stops the operation of the water pump in the water pump set 1, and the full variable frequency constant pressure water supply control system enters a sleep state; when the full-variable-frequency constant-pressure water supply control system simultaneously meets a fourth condition and a fifth condition, entering a system starting mode; the fourth condition is that the full variable frequency constant pressure water supply control system is in a sleep state; the fifth condition is that the real-time pressure is less than or equal to the wake-up pressure.
The starting weight of each water pump in the water pump set 1 is inversely proportional to the running time; the water pumps in the water pump group 1 determine a starting sequence according to the starting weight, namely the longer the running time of the water pumps is, the later the starting sequence is.
The control method provided by the application further comprises a fourth control mode; when any one or more of the water pump groups 1 fails, entering a fourth control mode; in a fourth control mode: any one or any plurality of water pumps that have failed in the water pump group 1 are eliminated.
The following further describes the full-variable-frequency constant-pressure water supply control system and control method provided by the present application:
the number of the water pumps and the frequency converters is in one-to-one correspondence.
In fig. 4, a water pump group 1(M1, M2, M3) and a frequency converter group 2(VVVF1, VVVF2, VVVF3) are in a one-to-one correspondence relationship, and one frequency converter controls one water pump; the logic controller 4(PLC) reads the operation data (rotating speed, current, voltage and the like) of the frequency converter group 2 through the RS485 communication interface; parameters (set pressure, pump adding delay, pump reducing frequency, alternation time, P value, I value and the like) required by the system are set on a touch screen 3(HMI), and the running state and the running data of the water pump group 1 and the frequency converter group 2 of the system are displayed at the same time; the field instrument 5 collects system real-time data (pressure, temperature, flow rate and the like) and transmits the data to the logic controller 4 (PLC); the logic controller 4(PLC) compares the set pressure with the actual pressure on site, calculates and outputs corresponding proper operating frequency to the frequency converter group 2(VVVF1, VVF2 and VVF3) through PID to adjust the operation of the water pump group 1(M1, M2 and M3), so that the water supply equipment can maintain constant-pressure operation, and closed-loop control is realized.
The specific working principle of the full-variable-frequency constant-pressure water supply control system (hereinafter referred to as the system) in actual operation provided by the application is as follows:
(a) when the system is started, any water pump is connected in a frequency conversion mode, and soft start is realized through a frequency converter.
(b) And the logic controller 4 uniformly adjusts the rotating speed of all variable frequency water pumps through PID operation to keep the pressure of the pipe network constant.
(c) Along with the increase of water consumption, namely a first control mode, when the pressure detected at the water outlet pipeline of the system is smaller than the set pressure value of the system, the rotating speed of the water pump is automatically increased to enable the outlet pressure to be increased to be close to the set pressure value, the logic controller 4 judges at a first judgment time node, if the pressure is not constant within the pump adding delay time (which can be set), the system puts another variable frequency pump into the system, the operating frequencies of the two variable frequency pumps are consistent, the frequencies are uniformly adjusted, and the pumps are added in a circulating mode until the pressure is constant.
(d) Along with the reduction of the water consumption, namely a second control mode, when the pressure detected at the water outlet pipeline of the system is greater than the set pressure value of the system, the rotating speed of all frequency conversion pumps is automatically reduced, so that the outlet pressure is reduced to be close to the set pressure value, and the logic controller 4 carries out judgment at a second judgment time node; if the frequency of the variable frequency pump is reduced to a frequency reduced pump (can be set), the outlet pressure is still larger than a set pressure value, and the system stops the operation of the water pump by the principle of starting and stopping firstly until the pressure is constant.
(e) When only one variable frequency pump is left to operate, namely the third control mode, if the water consumption is further reduced, the operating frequency of the variable frequency pump is reduced to the sleep frequency (which can be set), after the sleep delay (which can be set) for a certain time, the system automatically stops the operation of the pump, enters the sleep state, and when the system pressure is reduced to the awakening pressure (which can be set), the water pump automatically operates.
(f) Under the condition that all water pumps are started after being stopped or the time (which can be set) is alternated, the water pumps alternately operate, and the working time of each pump is ensured to be the same, so that a certain pump is prevented from operating for a long time, and the failure rate is increased.
(g) When any one or more frequency converters or water pumps in the system are in failure, namely in the fourth control mode, the system automatically removes the failed pumps to form a new system, so that normal water supply on site is ensured, and the working efficiency of the system is improved.
The inventor of the present invention has made extensive and intensive studies and discloses a full variable frequency constant pressure water supply control system and a control method, wherein in a conventional one-control-multiple control system, each pump is provided with a frequency converter, and the system comprises: n water pumps (N is less than or equal to 6), N frequency converters (N is less than or equal to 6), a logic controller, a touch screen, a field data acquisition unit and the like;
the number N of the water pumps and the frequency converters is an integer which is more than or equal to 2 and less than or equal to 6.
The attached figures 1,2 and 3 are schematic diagrams of a three-frequency-conversion constant-pressure water supply control system, and the control system comprises: three frequency converters (VVVF1, VVVF2, VVVF3), three circuit breakers (QF10, QF11 and QF12), three water pumps (M1, M2 and M3), a logic controller (PLC), a touch screen (HMI), two fuses (FU1 and FU2), five intermediate relays (KA1 and KA2, KA3, KA4 and KA5), five indicator lamps (HL1, HL2, HL3, HL4 and HL5), four transfer switches (SA1, SA2, SA3 and SA4), a switching power supply (S), a float Switch (SL) and a pressure transmitter (BYR).
In the figure 1, (L1, L2, L3 and N) are 380V/50Hz three-phase four-wire system power inlet wires for supplying power to a system, and circuit breakers (QF10, QF11 and QF12) are respectively connected with three frequency converters (VVVF1, VVVVF 2 and VVVF3) for protecting circuits from overheating, overload, open phase, short circuit and the like;
in the attached figure 1, three frequency converters (VVVF1, VVVF2 and VVVF3) are respectively connected with three water pumps (M1, M2 and M3) to control the operation of the water pumps; meanwhile, the operation parameters (current, voltage, frequency and the like) of the frequency converter are communicated and transmitted with a logic controller (PLC) in the attached figure 2 through an RS485 interface, the logic controller (PLC) outputs the operation frequency of the water pump through PID operation, and the operation frequency is transmitted to three frequency converters (VVVF1, VVVF2 and VVF3) through voltage signals of 0-10V to control the operation of the water pump.
The three frequency converters (VVVF1, VVVF2 and VVVF3) in the figure 1 output frequency converter faults to a logic controller (PLC) in the figure 2 by switching value signals. When the frequency converter is in fault, the fault frequency converter can be eliminated through a logic controller (PLC) written by a corresponding program to form a new system, and normal water supply of the system is ensured.
In the attached figure 2, a logic controller (PLC) and a touch screen (HMI) set parameters (set pressure, pump adding delay, pump reducing frequency, rotation time, P value, I value and the like) required by a system on the touch screen (HMI) through an RS485 interface, and simultaneously display and store the running state and running data (running state, fault state, pressure, frequency, liquid level, current, voltage and the like) of the system.
The logic controller (PLC) in fig. 2 receiving the switching value signal from fig. 3 includes: the automatic operation signal KA4, the water level signal KA5 and the 4-20 mA outlet pressure signal detected by the pressure transmitter (BYR). When the automatic signal KA4 is closed, the system is automatically put into operation, the system compares and calculates the output operation frequency according to the outlet pressure and the set pressure, and the output operation frequency is transmitted to frequency converters (VVVF1, VVVF2 and VVVF3) in the attached diagram 1 through 4-20 mA current signals so as to keep the system in constant-voltage operation.
The logic controller (PLC) in figure 2 is programmed to increase or decrease the pump according to the comparison between the outlet pressure and the set pressure, the output of the PLC is connected with the coil of the intermediate relay (KA1, KA2, KA3), and the PLC controls the input and the cut-off of the frequency converters (VVVF1, VVF2, VVF3) in figure 1 respectively.
In the attached figure 2, an intermediate relay KA5 is a water level signal, and when the opening point of KA5 is closed, the water level signal is a water shortage signal, at the moment, the system stops running, and the water pump is prevented from idling.
In fig. 2, an indicator lamp HL5 is a flashing buzzer, and when the system has a fault, an alarm sound is given.
In fig. 3, an indicator lamp HL1 is used for power supply indication, so that the lamp is on, and the lamp is off after power failure. The indicator lamps (HL2, HL3 and HL4) are running indicator lamps of the water pump, the running indicator lamps are on, and the running indicator lamps are off when the running indicator lamps stop.
In fig. 3, a change-over switch SA1 is used for selecting automatic or manual operation of the system, and the automatic operation is selected, and the system operates under the control of outlet pressure; when the manual operation is selected, the start and stop of the three pumps are respectively and manually controlled by the change-over switches (SA2, SA3 and SA 4).
The switching power supply (S) of fig. 3 converts AC220V to DC24V, which powers the logic controller (PLC) and outlet pressure transmitter (BYR) of fig. 2, respectively.
Known in this embodiment, a special converter is all independently configured to every water pump, and the converter is according to logic controller PLC's PID output automatically regulated water pump rotational speed, realizes the frequency and transfers in unison, reaches the efficiency equilibrium under the many water pump operational aspect, no matter how the system operating condition changes, and the water pump is moved in the high efficiency district all the time, can not appear the extravagant phenomenon of energy consumption, reaches more ideal energy-conserving effect.
Meanwhile, the system also has the advantages of soft start and soft stop, overpressure protection, water shortage protection, fault pump crossing, stable pressure switching of the water pump and the like. The stability, the safety and the reliability of the system are greatly improved.
It is noted that, in the present patent application, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the use of the verb "comprise a" to define an element does not exclude the presence of another, same element in a process, method, article, or apparatus that comprises the element. In the present patent application, if it is mentioned that a certain action is executed according to a certain element, it means that the action is executed according to at least the element, and two cases are included: performing the action based only on the element, and performing the action based on the element and other elements. The expression of a plurality of, a plurality of and the like includes 2, 2 and more than 2, more than 2 and more than 2.
This specification includes combinations of the various embodiments described herein. Separate references to "one embodiment" or a particular embodiment, etc., do not necessarily refer to the same embodiment; however, these embodiments are not mutually exclusive, unless indicated as mutually exclusive or as would be apparent to one of ordinary skill in the art. It should be noted that the term "or" is used in this specification in a non-exclusive sense unless the context clearly dictates otherwise.
All documents mentioned in this application are to be considered as being incorporated in their entirety into the disclosure of this application so as to be subject to modification as necessary. Further, it is understood that various changes or modifications may be made to the present application by those skilled in the art after reading the above disclosure of the present application, and such equivalents are also within the scope of the present application as claimed.
Claims (10)
1. A full frequency conversion constant pressure water supply control system is characterized by comprising a water pump set (1) and a frequency converter set (2):
the water pump sets (1) respectively correspond to the frequency converter sets (2);
the frequency converter group (2): the pressure regulator is used for regulating the real-time pressure of the water pump set (1);
full frequency conversion constant voltage water supply control system still includes:
logic controller (4): is used for reading the operation data of the frequency converter group (2).
2. The full variable frequency constant pressure water supply control system according to claim 1, wherein the preset parameters include a wake-up pressure, a preset pressure value, a pump adding delay, a switching time, a pump reducing frequency, a sleep delay time, a preset time, a proportional time, and an integral time; the operation data comprises operation rotating speed, operation frequency, operation time, operation current and operation voltage; the real-time data comprises real-time pressure, real-time temperature and real-time flow;
full frequency constant voltage water supply control system still includes:
touch screen (3): the system comprises a full-variable-frequency constant-pressure water supply control system, a frequency converter, a frequency;
field instrument (5): the system is used for acquiring real-time data of the full-variable-frequency constant-pressure water supply control system and transmitting the real-time data to the logic controller (4);
the touch screen (3) is also used for displaying the running states and the running data of the number of the water pump sets (1) and the frequency converter sets (2).
3. A control method of a full frequency conversion constant pressure water supply control system is characterized in that:
the full-variable-frequency constant-pressure water supply control system comprises a water pump set (1), a frequency converter set (2) and a logic controller (4); the frequency converter group (2) can control the water pump group (1); the frequency converter group (2) is in communication connection with the logic controller (4);
the control method comprises the following steps:
the logic controller (4) reads system real-time data and preset parameters; the logic controller (4) compares the real-time data of the system with preset parameters, calculates the operating frequency and outputs the operating frequency to the frequency converter group (2); the frequency converter group (2) controls the operation of the water pump group (1) according to the operation frequency.
4. The control method of the full variable frequency constant pressure water supply control system according to claim 3, characterized in that:
the full-frequency constant-pressure water supply control system also comprises a touch screen (3); the touch screen (3) is in communication connection with the logic controller (4);
the control method further comprises the following steps:
the logic controller (4) reads the operation data of the water pump set (1) and the operation data of the frequency converter set (2), and sends the operation data to the touch screen (3) for display;
the preset parameters are set through the touch screen (3).
5. The control method of the full variable frequency constant pressure water supply control system as claimed in claim 3 or 4, wherein the control method comprises a system start mode;
when the full variable frequency constant pressure water supply control system is started, entering a system starting mode;
in a system start-up mode:
any set water pump in the water pump group (1) is accessed in a frequency conversion mode and is soft started through a corresponding frequency converter in the frequency converter group (2); the logic controller (4) calculates and adjusts the operating frequency of all frequency converters in the frequency converter group (2) in a unified manner, and further controls the rotating speed of all water pumps in the water pump group (1), so that the pressure of a pipe network is kept constant.
6. The control method of the full variable frequency constant pressure water supply control system as claimed in claim 5, comprising a first control mode;
the preset parameters comprise preset pressure and pumping delay time, and the preset pressure is a pressure value or a pressure range; the system real-time data comprises real-time pressure;
when the real-time pressure is smaller than the preset pressure, entering a first control mode;
in the first control mode:
the logic controller (4) adjusts the rotating speed of the water pump in the working state in the water pump set (1) through the frequency converter set (2) to increase the real-time pressure until the real-time pressure is equal to the preset pressure or the real-time pressure is within the preset pressure range;
the logic controller (4) judges at a first judgment time node:
if the real-time pressure is equal to the preset pressure or the real-time pressure is within the preset pressure range, the frequency converter group (2) and the water pump group (1) continue to operate according to a set mode;
if the real-time pressure is smaller than the preset pressure, whether a water pump in an unoperated state exists in the water pump set (1) or not is continuously judged: if the frequency converter group does not exist, the frequency converter group (2) and the water pump group (1) are continuously operated according to a set mode; if the frequency converter exists, adding a water pump, wherein the operating frequency of the frequency converter corresponding to the newly added water pump is the same as the operating frequency of the frequency converter corresponding to the water pump in the working state, and meanwhile, updating the starting time point of the first judgment time node to be the operating time point of the newly added water pump by the logic controller (4);
the first judgment time node is a corresponding time point after the pump delay time from the initial time point; the starting point in time is by default the point in time of entering the first control mode.
7. The control method of the full frequency conversion constant pressure water supply control system according to claim 5, further comprising a second control mode;
the preset parameters comprise preset pressure and pump reduction frequency, and the preset pressure is a pressure value or a pressure range; the system real-time data comprises real-time pressure;
when the real-time pressure is greater than the preset pressure, entering a second control mode;
in a second control mode:
the logic controller (4) adjusts the rotating speed of the water pump in the working state in the water pump set (1) through the frequency converter set (2) to reduce the real-time pressure until the real-time pressure is equal to the preset pressure or the real-time pressure is in the preset pressure range;
the logic controller (4) judges at a second judgment time node:
if the current real-time pressure is not greater than the preset pressure, the frequency converter group (2) and the water pump group (1) continue to operate according to a set mode;
if the current real-time pressure is larger than the preset pressure, stopping the water pump started firstly, and meanwhile, updating the starting time point of the second judgment time node to be the stopping time point of the newly stopped water pump by the logic controller (4);
and the second judgment time node is a time point from the starting time point, the operating frequency of the frequency converter group (2) is less than or equal to the pump reduction frequency for the first time, and the number of the water pumps in the working state in the water pump group (1) is greater than 1.
8. The control method of the full variable frequency constant pressure water supply control system as claimed in claim 5, further comprising a third control mode;
the preset parameters comprise preset pressure, sleep frequency, sleep delay and awakening pressure, and the preset pressure is a pressure value or a pressure range; the system real-time data comprises real-time pressure; when the full-variable-frequency constant-pressure water supply control system simultaneously meets the first condition, the second condition and the third condition, entering a third control mode;
the first condition is that one and only one water pump in the water pump group (1) is in a working state;
the second condition is that the real-time pressure is greater than the preset pressure;
the third condition is that the running frequency of a frequency converter corresponding to the water pump in the working state is less than the sleep frequency, and the duration time of the state that the running frequency is less than the sleep frequency is greater than the sleep delay;
in a third control mode:
the logic controller (4) stops the operation of the water pump in the water pump set (1), and the full variable frequency constant pressure water supply control system enters a sleep state;
when the full-variable-frequency constant-pressure water supply control system simultaneously meets a fourth condition and a fifth condition, entering a system starting mode;
the fourth condition is that the full variable frequency constant pressure water supply control system is in a sleep state;
the fifth condition is that the real-time pressure is less than or equal to the wake-up pressure.
9. The control method of a full variable frequency constant pressure water supply control system according to claim 5, wherein the start weight of each water pump in the water pump set (1) is inversely proportional to the operation time; and each water pump in the water pump set (1) determines a starting sequence according to the starting weight, namely the longer the running time of the water pump is, the later the starting sequence is.
10. The control method of a full variable frequency constant pressure water supply control system according to claim 3, further comprising a fourth control mode;
entering a fourth control mode when any one or more of the plurality of water pump groups (1) fails;
in a fourth control mode:
and (2) eliminating any one or more water pumps which have failed in the water pump group (1).
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| CN202110112025.0A CN114810565A (en) | 2021-01-27 | 2021-01-27 | Full-variable-frequency constant-pressure water supply control system and control method |
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| CN202110112025.0A CN114810565A (en) | 2021-01-27 | 2021-01-27 | Full-variable-frequency constant-pressure water supply control system and control method |
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Application publication date: 20220729 |