KR101183907B1 - Inverter booster pump system and method for controlling using this - Google Patents

Abstract

PURPOSE: An inverter booster pump system equipped with pumps in a row and a control method thereof are provided to reduce power consumption as the pumps are optimally maintained with same output. CONSTITUTION: An inverter booster pump system comprises an pressure sensor(30), a pump unit(70), and a control unit(40). The pressure sensor measures the pressure of a supply pipe. The pump unit comprises a plurality of pumps connected in a row, and provides discharge power to the supply pipe. The control unit comprises an inverter and a controller. The inverter changes the driving frequency of each pump. The controller controls the pump unit.

Description

Inverter booster pump system and method for controlling using this}

The present invention relates to a pump, and more particularly, to a pump system having a plurality of pumps connected in parallel and a control method for controlling the same.

The booster pump system refers to a pump system made by connecting two induction motors of Xiang. These booster pump systems are widely used in apartment complexes, buildings, and residential buildings.

When the booster pump system calculates the required water pressure and inputs it to the controller connected to the booster pump system, the controller plays a role of keeping the current pressure constant so as to correspond to the set pressure through PID control.

In this case, an inverter is used to control the electric motor, and the inverter uses a voltage / frequency (V / F) control scheme to change an output by changing a three-phase frequency.

The control method of such a booster pump system is disclosed in Republic of Korea Patent No. 10-2033927, Republic of Korea Patent No. 10-0300305.

However, the control method of the booster pump system according to the prior art described above does not drive the pump of the highest efficiency among pumps capable of pumping the required capacity in driving the pump, but the maximum pumping amount of any one pump. And the remaining pump or sub small pump for the excess capacity is controlled. Accordingly, in the case of the booster pump system according to the prior art there is a problem that the energy efficiency is not good.

The present invention is to solve the problems of the prior art as described above, an object of the present invention is to provide an inverter booster pump control method excellent in energy efficiency.

In particular, it is an object of the present invention to provide a pump system control method with improved efficiency by appropriately controlling a booster pump in an environment that is not significantly affected by a lift.

According to a feature of the present invention for achieving the object as described above, the present invention is connected to a supply pipe for supplying a fluid to the use space to provide a pressure for discharging the fluid, a plurality of which are connected in parallel In the inverter booster pump, a pressure sensor for measuring the pressure of the supply pipe, a pump unit connected to the plurality of pumps in parallel to provide the output power to the supply pipe, drive frequency of each pump constituting the pump unit And a control unit including an inverter for varying the controller and a controller for controlling the pump unit, wherein the control unit includes: i) if the measured pressure measured by the pressure sensor has an error with the set pressure; Increase the drive frequency of at least one pump that is running, or Or ii) reduce the drive frequency of at least one pump already in operation, or stop the operation of any one of the pumps, and the control unit controls the at least one pump in operation to have the same output in conjunction. do.

When the measured pressure measured by the pressure sensor is smaller than the set pressure, the control unit is 1 when the sum of the n pump outputs currently operating among the total N pumps is equal to the minimum output of n + 1 pumps. Additional pumps

When the measured pressure measured by the pressure sensor is larger than the set pressure, the control unit is one of the total of N pumps, when the minimum output of the currently operating n pumps is equal to the output of the n-1 pumps. Stop the pump.

The control unit calculates an error by comparing the measured pressure and the set pressure measured by the pressure sensor, and calculates the output value through the PID calculation with the error.

According to another feature of the invention, connected to the supply pipe for supplying a fluid to the use space to provide a pressure for discharging the fluid, a plurality of the control method of the inverter booster pump used in parallel, pressure sensor According to the measuring step of measuring the pressure of the supply pipe, the comparison step of comparing the measured pressure and the set pressure of the supply pipe measured by the pressure sensor, and the error generated in the comparison step, i) at least Reducing the driving frequency of one or more pumps or stopping the operation of any one pump; or ii) increasing the driving frequency of the at least one pump that is already in operation or additionally operating the idle pump; The remaining multiple pumps operating after being controlled have the same output power and correspond to the set pressure. It is configured to include a lock control method comprising: sync.

In the controlling step, as a result of comparing the measured pressure and the set pressure in the comparing step, i) when the measured pressure is less than the set pressure, the driving frequency of the at least one pump which is already in operation is increased or the pump being idle is additionally operated. , ii) when the measured pressure is greater than the set pressure, it is characterized in that the driving frequency of at least one or more pumps in operation is reduced or the operation of any one pump is stopped.

In the controlling step, when the measured pressure and the set pressure are compared in the comparing step, i) when the measured pressure is smaller than the set pressure and the sum of the maximum outputs of the n pumps being operated is greater than the set pressure, Increasing the driving frequency of the two pumps; Iii) if the measured pressure is greater than the set pressure and the sum of the minimum outputs of the n pumps in operation is less than the set pressure, reduce the drive frequency of the n pumps in operation and iv) If the sum of the minimum outputs of the n pumps in operation and greater than the set pressure is greater than the set pressure, the operation of any one of the n pumps in operation is stopped.

In the controlling step, i) control to additionally operate one idle pump is performed at a point where the minimum output of n + 1 pumps is equal to the output of n pumps in operation, and ii) n pumps in operation. The control to stop the operation of any one of the pumps is made when the minimum output of the n pumps in operation is equal to the output of the n-1 pumps.

After the output of at least one pump is equalized through the sinking step, the pressure sensor returns to the measuring step of measuring the pressure in the supply pipe and repeats each step, and further control or stoppage of the pump is necessary in the control step. In this case, after the at least one pre-operated pump enters a proper operation state, a delay step for causing the pump to be additionally operated or stopped is further included.

In the control step, an output value is calculated through PID calculation with the error calculated in the comparison step.

In the inverter inverter booster pump system and the control method of the inverter booster pump system using the same according to the present invention as described above, the following effects can be expected.

In the present invention, since a plurality of pumps connected in parallel to each other is controlled to maintain the optimum value while having the same output to each other by the control unit, there is an effect that can reduce the power consumption.

Particularly, in the present invention, the additional pump is not driven after any one pump is driven at the maximum load ratio, but a plurality of pumps are appropriately distributed and driven to have the same output with each other, thereby preventing wear of a specific pump. You can also expect the effect.

In the present invention, the drive frequency of the booster pump is increased or decreased by the inverter, and at the time of adjusting the driving frequency, the output of the n pumps is equal to the output of the n + 1 pumps. By starting or stopping, excessive torque on a particular pump can be prevented.

1 is a schematic structural view showing the structure of a preferred embodiment of an inverter booster pump system according to the present invention;
Figure 2 is a flow chart showing sequentially a method for controlling the booster pump system using an embodiment of the present invention.
3 and 4 are graphs showing the output generated in the process of sequentially operating the booster pump using an embodiment of the present invention.
Figure 5 is a graph showing the pressure, power and efficiency in the case of controlling the output using a conventional individual pump system.
Figure 6 is a graph showing the pressure, power and efficiency when controlling the output using the inverter booster pump system according to the present invention.
7 is a graph comparing the efficiency of the conventional individual pump system shown in FIGS. 5 and 6 with the inverter booster pump system according to the present invention.
8 is a table showing the results of testing the existing individual pump system shown in Figures 5 and 6 and the inverter booster pump system according to the present invention.

Hereinafter, a specific embodiment of the inverter booster pump system and the control method of the inverter booster pump system using the same according to the present invention as described above will be described in detail with reference to the accompanying drawings.

1 shows a structural diagram of a preferred embodiment of an inverter booster pump system according to the present invention.

Accordingly, the inverter booster pump system according to the embodiment of the present invention is provided with a reservoir T1 for storing fluid, and the fluid filled in the reservoir T1 is introduced into the inlet pipe 10 by the pump unit 70 to be described below. Inflow to the), the fluid of the inlet pipe 10 is distributed to each space through the supply pipe (20).

At this time, the fluid delivered from the inlet pipe 10 may be temporarily stored in the pressure tank (T2). The pressure tank (T2) serves to prevent a sudden change in the pressure of the fluid exiting the outside through the supply pipe 20 by temporarily storing the fluid.

On the other hand, the supply pipe 20 is provided with a pressure sensor (30). The pressure sensor 30 is for measuring the pressure of the fluid discharged to the outside through the supply pipe 20, for this purpose, the pressure sensor 30 is preferably installed on the outlet side of the supply pipe (20).

The control unit 40 is connected to the pump unit 70. The control unit 40 is to change the frequency supplied to the pump to adjust the rotational speed of the pump, or to adjust the number of pumps that are operated to change the pressure of the resulting fluid, in this embodiment It is configured to include an inverter module 60 and the controller 50.

The inverter module 60 is connected to the booster pump to adjust the driving frequency of each pump. In FIG. 1, a total of three inverters 61, 63, and 65 are connected to separate pumps, respectively. The inverter module 60 increases or decreases the driving frequency of the booster pump according to the command signal of the controller 50, and as a result, adjusts the output of the pump unit 70. In this case, the command signal transmitted from the controller 50 may be pulse wide modulation (PWM).

The controller 50 controls the pump unit 70 by transmitting an appropriate control signal to the inverter module 60 to compare the measured pressure and the set pressure transmitted from the pressure sensor 30 to send an appropriate control signal. do. In addition, the controller 50 generates an overall operation logic for driving the inverter booster pump system, such as PID control, which will be described below, or serves to control the system through the input from the user.

More precisely, if the measured pressure measured by the pressure sensor 30 is in error with the set pressure, i) increase the drive frequency of at least one pump already in operation, or Additionally operating the idle pump, or ii) reducing the drive frequency of at least one pump that is already in operation, or controlling to stop the operation of any one of the pumps.

That is, when the pressure of the fluid discharged through the supply pipe 20 is smaller or larger than the desired set pressure, the control unit 40 performs an operation of correcting the pressure to be close to the set pressure.

At this time, the control unit 40 is controlled so that at least one or more pumps being operated to have the same output. This is for the most efficient operation of a plurality of booster pumps connected in parallel with each other, the details of which will be described below.

Hereinafter, a method of controlling the system using the inverter booster pump system will be described in detail with reference to the accompanying drawings.

2 is a sequential flowchart illustrating a method of controlling a booster pump system using an embodiment of the present invention.

As shown in the figure, the pressure sensor 30 first measures the pressure of the pressure sensor 30 in the supply pipe 20. (S100) This is for measuring the flow rate discharged through the supply pipe 20 will be.

Then, the measured pressure and the set pressure of the supply pipe 20 measured by the pressure sensor 30 are compared. (S101) The comparison operation is performed by the controller 50. If an error occurs as a result, the following operation is performed.

That is, according to the error generated in the comparison step, if the measured pressure is less than the set pressure, because the flow rate is insufficient, the pressure must be increased, thus increasing the drive frequency of the pump or start the additional pump.

In other words, first compare the possible pressure (flow rate) and the set pressure (flow rate) to the maximum output of the n pumps already in operation (S102), and if the sum of the maximum output of the n pumps is greater than the set pressure is already operating The driving frequency of the n pumps being increased is increased (S103). This is because the desired flow rate can be obtained by increasing the pressure by controlling the n already operating pumps without additional pump starting.

And, comparing the sum of the maximum output of the n pumps already in operation and the set pressure (S102), if the set pressure is greater, the desired flow rate can not be obtained by adjusting the drive frequency of the pump already in operation, the additional pump start This is necessary. (S104)

At this time, as will be described again below, the minimum output of the n + 1 pump is set to the set pressure so as to be more advantageous in terms of efficiency and durability of the pump, rather than comparing the sum of the maximum output of the n pumps and the set pressure. If the same, additional pumps can be started.

More precisely,

"Maximum output power that can be driven by n pumps = n + 1 pump minimum power"

In the previous step, if the 'maximum output <set pressure' that can be driven by n pumps in the previous step S102, an additional pump is started in addition to the current n pumps. The same can be applied when determining the stop of driving.)

For example, when the minimum output of each pump is 50% and two pumps are running, the optimum maximum output of the two pumps is equal to the minimum output of three pumps, that is 150%. Therefore, if the output value is insufficient, the driving frequency is increased first, and when the output of the two pumps becomes 150%, the other pump is additionally driven.

On the contrary, the optimum maximum output of the pump can be calculated from the input value. More precisely,

"Maximum power consumption (input) required for running n pumps = power consumption required for minimum operation of n + 1 pumps (input)"

With the maximum power consumption (input) value pre-input, the pressure (flow rate) <set pressure (flow rate) possible at the optimum maximum power consumption required for the operation of n pumps, An additional pump will be started.

Of course, the optimum maximum output power or the optimum maximum power consumption of the pump may be calculated in advance through experimental data. For example, the most appropriate maximum output value is calculated in consideration of the wear rate of the pump, the amount of power consumed, and the like is compared with the set pressure.

In addition, by applying the fuzzy theory, the control unit 40 may be set to optimize the currently driven system in response to the characteristics change according to the aging of the pump or other environmental changes.

On the other hand, if the measured pressure is larger by comparing the set pressure and the measured pressure (S101), the sum of the minimum outputs of the n pumps already in operation is compared with the set pressure (S110). The flow rate should be reduced by reducing the driving frequency of the pump in operation. (S111) Since the set pressure is greater than the pressure due to the minimum output from the n pumps in operation, the flow rate is sufficiently reduced by reducing the driving frequency of the pump in operation. Because it can reduce.

For example, if the set pressure results in a flow rate of 110%, the measured flow rate is 120%, and two pumps with a minimum output of 50% each are in operation, the excess 10% flow rate will be two pumps. By reducing the output of each by 5%, it is possible to meet the set value. Even if the output is reduced by 5%, each pump will have 50% of output, so it is possible because it is within the range of the minimum output.

When the sum of the minimum outputs of the n pumps already in operation is compared with the set pressure (S110), if the set pressure is smaller, the output frequency is lower than the set pressure even if the output is reduced by reducing the driving frequency of the n pumps already in operation. Since it becomes high, it is necessary to stop either pump. (S112)

That is, one of the n pumps in operation is stopped and as a result, only n-1 pumps are driven.

 For example, if the changed set pressure results in a flow rate of 141%, the measured flow rate is 180%, and three pumps with a minimum output of 50% are in operation, the excess 39% flow rate is three The pump outputs must be reduced by 13% each, but each pump will have a power output of 47%, exceeding the minimum output. In this case, therefore, an operation for stopping any one of the three pumps is required.

On the other hand, after adjusting the output of the booster pump (S103, S111) or the operation of adjusting the number of pumps (S104, S112) in this way, the same output (drive frequency) by interlocking a plurality of pumps that are operated The sink is adjusted to have a (S120).

Such a sink is for driving the most efficient system, which will be described with reference to the table shown in FIG. 8.

8 is a table showing the results of testing the existing individual pump system and the inverter booster pump system according to the present invention, the left side represents the experimental value based on one individual pump system, the right side using the present invention The values tested with two pumps are shown. Here, the output pressure represents the pressure measured by the pressure sensor 30, the input power means the power entered to drive the pump, and the leftmost drive frequency represents the frequency related to the rotation of the driven pump. And efficiency is output pressure divided by input power.

As shown in the figure, in order to increase the output pressure, the driving frequency of the pump must be increased to increase the rotation speed.

At this time, in order to compare the two experimental examples at a specific value, looking at the point where the output pressure is 2.63bar, the conventional one pump system is required drive frequency is 60hz, while in the present invention it can be seen that the required frequency is 40hz have. It can be seen that the case of the present invention can obtain the same output pressure at a lower driving frequency. In the case of the present invention, since it is an experiment with two pumps, it is necessary to accurately determine the efficiency based on this.

The input power related to efficiency is proportional to the power of the pump, that is, the shaft horsepower, and according to the similar law of the pump, the shaft horsepower of the pump is proportional to the cube of the rotational speed (driving frequency) of the pump. Therefore, when calculating the efficiency of the present invention in the previous example,

(40/60) ³ = 0.296,

With two pumps, this results in approximately 0.59 or 59% of the power of one conventional pump system.

As such, it can be seen that in terms of efficiency, it is more efficient to distribute the output to a plurality of pumps as compared to implementing a specific pressure with one pump. In particular, this system can be applied more efficiently in the environment where flow rate is important without being greatly affected by the head.

5 and 6 show the results of experiments with one conventional pump system described above and two pump systems using the present invention. In this case, the efficiency indicates an output pressure / input power and is intended to indicate a rough efficiency. 7 shows a graph comparing the efficiency of these two cases, as can be seen that the efficiency of the present invention is better.

The above control steps are summarized below. That is, the control step is a result of comparing the measured pressure and the set pressure in the comparison step,

i) If the measured pressure is less than the set pressure and the proper maximum output of the n pumps in operation is greater than the set pressure, increase the drive frequency of the n pumps in operation.

ii) If the measured pressure is less than the set pressure and the proper maximum output power of the n running pumps does not reach the set pressure, one additional idle pump is started in addition to the running n pumps.

iii) If the measured pressure is greater than the set pressure and the sum of the minimum outputs of the n pumps in operation is less than the set pressure, reduce the drive frequency of the n pumps in operation.

iv) If the measured pressure is greater than the set pressure and the sum of the minimum outputs of the n pumps in operation is greater than the set pressure, then one of the n pumps in operation is stopped.

At this time, the additional start or stop of the pump is preferably made as follows. That is, in the control step,

i) Control to additionally operate one idle pump is made when the output of the already running n pumps is equal to the minimum output of n + 1 pumps,

ii) The control to stop the operation of any one of the n pumps in operation is made when the output of the n pumps in operation is equal to the proper maximum output of n-1 pumps.

This is more efficient in the case of booster pump systems in which many are connected in parallel, as shown above, and the distribution of the number of pumps is selected with the minimum output of the pump.

For reference, FIGS. 3 and 4 show graphs showing outputs generated by sequentially operating booster pumps using two booster pump systems and three booster pump systems, respectively.

As can be seen, the n + 1 th pump is started at a specific point in the case of a gas flow shortage, and finally each pump is maintained to operate with the same output.

On the other hand, back to Figure 2, after the sink step (S120), and maintains the proper operation state (S130) In the proper operation state, a plurality of booster pumps having the same output through the sink for a predetermined time or more. By starting, the output is maintained for a predetermined time before the output is re-measured by the pressure sensor 30. This prevents the pump from being damaged due to a sudden change in the output of the pump during repeated control processes.

In other words, if the pump is required to further operate or stop in the control step, a delay step may be further performed so that the pump is additionally operated or stopped after the at least one pump which is already in operation enters the proper operation state. It is. Of course, such a proper operating state can be made under various conditions depending on the selection and input of the operator.

Finally, as the above process is repeated, the control process is repeated so that the set pressure and the measured pressure are close to each other. That is, after the output of at least one pump is equalized through the sinking step, the pressure sensor 30 returns to the measuring step of measuring the pressure of the supply pipe 20 and repeats each step.

Meanwhile, in the control process, interlocked PID control may be utilized. That is, the output value is calculated through PID calculation using the error calculated in the comparing step. When it is difficult to derive an accurate mathematical model, tuning through PID control is performed by Ziegler-Nichols tuning rule. It is also possible.

The rights of the present invention are not limited to the embodiments described above, but are defined by the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. It is self-evident.

20: supply piping 30: pressure sensor
40: control unit 70: pump unit

Claims (9)

In the inverter booster pump is connected to the supply pipe for supplying the fluid to the use space to provide a pressure for discharging the fluid, a plurality of them are connected in parallel,
A pressure sensor for measuring the pressure in the supply pipe,
A pump unit for connecting a plurality of pumps in parallel to provide a soil output to the supply pipe;
And a control unit including an inverter for varying a driving frequency of each pump constituting the pump unit and a controller for controlling the pump unit.
If the measured pressure measured by the pressure sensor is in error with the set pressure, i) increase the drive frequency of the at least one pump that is already in operation, or further operate the idle pump; or ii Reduce the drive frequency of at least one pump that is already running, or deactivate any one pump,
The control unit is an inverter booster pump system, characterized in that for controlling at least one pump in operation to have the same output.
According to claim 1, wherein when the measured pressure measured by the pressure sensor is less than the set pressure, the control unit of the total of N pumps, the sum of the n pump outputs currently operating of n + 1 pump If it is equal to the minimum output, let 1 pump run additionally,
If the measured pressure measured by the pressure sensor is greater than the set pressure, the control unit deactivates one pump if the minimum output of the currently operating n pumps out of the total N pumps is less than the set pressure. Inverter booster pump system, characterized in that.
The method of claim 1 or 2, wherein the control unit calculates an error by comparing the measured pressure measured by the pressure sensor and the set pressure, and calculates the output value through the PID calculation with the error. Inverter booster pump system, characterized in that.
In the control method of the inverter booster pump is connected to the supply pipe for supplying the fluid to the use space to provide a pressure for discharging the fluid, a plurality of them are connected in parallel,
A measuring step of measuring a pressure of the supply pipe by a pressure sensor;
A comparison step of comparing the measured pressure and the set pressure of the supply pipe measured by the pressure sensor;
Depending on the error generated in the comparison step, i) reduce the drive frequency of at least one pump in operation or stop the operation of any one pump, or ii) increase the drive frequency of at least one pump in operation or A control step for additionally operating the idle pump;
And a sink step of controlling the remaining plurality of pumps being operated after being controlled by the control step to correspond to the set pressure while having the same output to each other.
The method of claim 4, wherein the control step, as a result of comparing the measured pressure and the set pressure in the comparison step,
i) if the measured pressure is less than the set pressure, increase the drive frequency of at least one pump that is already in operation or
ii) when the measured pressure is greater than the set pressure, the control method of the inverter booster pump system, characterized in that to reduce the drive frequency of at least one or more pumps in operation or to stop the operation of any one pump.
The method of claim 4, wherein the control step, as a result of comparing the measured pressure and the set pressure in the comparison step,
i) If the measured pressure is less than the set pressure and the proper maximum output of the n pumps in operation is greater than the set pressure, increase the drive frequency of the n pumps in operation.
ii) If the measured pressure is less than the set pressure and the proper maximum output power of the n running pumps does not reach the set pressure, one additional idle pump is started in addition to the running n pumps.
iii) If the measured pressure is greater than the set pressure and the sum of the minimum outputs of the n pumps in operation is less than the set pressure, reduce the drive frequency of the n pumps in operation.
iv) When the measured pressure is greater than the set pressure and the sum of the minimum outputs of the n pumps in operation is greater than the set pressure, the inverter booster pump characterized in that the operation of any one of the n pumps in operation is stopped. Control method of the system.
The method of claim 5 or 6, wherein in the control step,
i) Control to additionally operate one idle pump is made when the minimum power of n + 1 pumps is equal to the output of n running pumps,
ii) Inverter booster pump, characterized in that the control to stop the operation of any one of the n pumps in operation is made when the output of the n pumps in operation is equal to the optimum maximum output of n-1 pumps. Control method of the system.
8. The method of claim 7, wherein after the output of the at least one pump is equalized through the sinking step, the pressure sensor returns to the measuring step of measuring the pressure in the supply pipe and repeats each step, and adding the pump in the control step. If operation or shutdown is necessary, further control is provided for the inverter booster pump system further comprising a delay step for the pump to be started or stopped after at least one pump is in proper operating condition. Way.
9. The control method of claim 8, wherein the control step calculates an output value through a coordinated PID calculation with the error calculated in the comparing step.

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