JP3324794B2 - Feed water pump control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water supply pump control system in which water is supplied using a pump driven at a variable speed by an electric motor whose speed is controlled by an inverter. The present invention relates to a water supply pump control device suitable for a system.

[0002]

2. Description of the Related Art A pump is required as a water supply system in an apartment house and various buildings. In such a case, the demand for water supply varies greatly depending on the date and time, such as daytime and nighttime, or work days and holidays. . For example, FIG. 10 shows a change in water supply demand in a certain water supply system in one day. As is clear from this, the water supply demand changes by several tens of times.

Therefore, in such a case, a pump driven at a variable speed by an electric motor whose speed is controlled by an inverter is conventionally used. At this time, the rating of a water supply device including the inverter, the electric motor, and the pump is as follows. The water supply load is selected according to the demand during the maximum time, and the inverter is used to reduce the number of revolutions of the motor from the rated value as the demand decreases, so that water supply that meets the demand can be performed. I was

[0004] That is, as shown in FIG. 11, the water supply amount Q of the pump will vary the rotational speed N as parameters, in the conventional water supply apparatus described above, the water supply amount Q _R at the rated rotational speed N _R to maximize water demand Q _M, i.e., Q _R = Q _M and selects the rated output of the motor so, was always to operate in the region below the rated rotational speed N _R.

[0005]

In the prior art, no consideration is given to the fact that the water supply system is operated at less than the maximum water supply load in many hours, and there is a problem in the efficient operation of the water supply system. was there. That is, in the prior art, for example, as shown in FIG. 10, in the case of a water supply system in which the water supply demand greatly fluctuates, the rating of the water supply device is shown in the demand during the time when the water supply load is maximum, for example, as shown in FIG. Water supply
(= Maximum water demand Q _M ).

However, as is apparent from FIG. 10, in many time zones, the amount of water used is much smaller, and the average water supply is considerably lower than the water supply a. Assuming that the capacity of the motor is selected according to the time when the demand for water supply is at its maximum,
In many situations , the motors and pumps are operated out of the point of maximum efficiency, which results in wasteful energy consumption and higher equipment costs. is there.

[0007] A first object of the present invention is to provide a link under a certain condition.
As continued overload operation enabled, efficiently normal in many of the time zone
It is an object of the present invention to provide a water supply pump control device which can be operated at a time and can suppress wasteful energy consumption and increase in equipment cost sufficiently. A second object of the present invention is to enable overload operation.
To, can be efficiently operated in a number of time zones, wasted energy - is sufficiently suppressed consumption and equipment cost increases, moreover Pont
When the pump is operated for a long period of time, a feedwater pump control device that can manage and display the service life limit of the motor from the cumulative addition value corresponding to the time when the motor is temporarily overloaded is provided. To provide. A third object of the present invention, in relation to the first object, is to provide a water supply pump control device which can be controlled so that the higher the temperature of the electric motor itself, the shorter the time that the electric motor is placed in an overload state. Is to do. A fourth object of the present invention is to enable efficient continuous operation in many time zones, to suppress unnecessary energy consumption and increase in equipment cost sufficiently, and when the temperature of the motor itself exceeds the allowable maximum temperature. It is an object of the present invention to provide a water supply pump control device in which a pump can be put into a shutdown state for the first time .

[0008]

SUMMARY OF THE INVENTION The first object of the present invention is to set the output frequency of the inverter to a value lower than the maximum water supply demand.
The drive frequency of the motor, which is predetermined according to the constant water supply
Inverter control means that can be controlled to be higher than
The motor is driven by the inverter control means.
Elapsed time from the start of operation beyond the operating frequency
Measurement means for measuring a value corresponding to the measurement means.
When the measured value exceeds a predetermined value set in advance
Sets the output frequency of the inverter below the drive frequency
It is achieved by configuring to set to . The second eye above
In general, the output frequency of the inverter must be
Of the motor that has been determined in advance corresponding to the predetermined
Invar that can be controlled to be higher than the drive frequency
Control means and the inverter control means.
Value corresponding to the time the machine has been operated above the above driving frequency
And a cumulative measuring means for cumulatively adding
Based on the measurement results by the measuring means, the service life of the motor
This is achieved by configuring to display degrees. The third object is that, in the measuring means, the measurement is performed by the electric motor.
As the temperature of the motor itself increases, the elapsed time is measured.
This is achieved by being measured as being greater than the value .
The fourth object is to increase the output frequency of the inverter to the maximum
Pre-determined for a given water supply that is less than the water demand
Can be controlled to be higher than the drive frequency of the
Inverter control means and
The motor starts to operate beyond the drive frequency
Measuring means for measuring the value according to the elapsed time from when
Temperature measurement means for measuring the temperature of the motor itself,
The measured value by the measuring means is a predetermined value set in advance.
If it exceeds, the inverter control means
The output frequency of the inverter should be set below the above drive frequency.
Control, while the motor itself is controlled by the temperature measuring means.
If the body temperature exceeds the maximum allowable temperature, the pump
Pump control means for controlling the operation of the
This is achieved by configuring

[0009]

According to the present invention, the inverter control means controls the electric motor in accordance with the increase of the demand for water supply to a predetermined water supply amount smaller than the maximum water supply demand.
The rotation speed is equal to or higher than the predetermined rotation speed, and the pump operates to increase the water supply capacity of the pump. Therefore, the maximum efficiency output of the motor can be considerably smaller than the output required for the maximum water demand, for example, about 70%, and the average value of the load during the operation time is close to the maximum efficiency load.
Since the, it can improve average efficiency, and it is possible to reduce the equipment cost.

Further, total measuring means, since the electric motor to calculate the time in the overload condition, to predict a temperature rise of the motor, so returned to the following state maximum efficiency Load This result is further increase in temperature proceeds Therefore, the operation can be continued safely and the possibility that the water supply operation stops even though the motor is overloaded can be sufficiently eliminated. Furthermore, after actually measuring the temperature of the motor itself,
If the temperature is higher, the motor is kept under control to reduce the time during which the motor is in overload operation, or if the pump is stopped due to its temperature exceeding the maximum allowable temperature, the motor is temporarily turned off. While being allowed to be placed in an overloaded state, it can be efficiently protected from the overloaded state. Furthermore, overload operation is allowed
While the pump is running for a long time
Easily predicts that the service life of the motor will naturally be shortened
However, at this time, the motor is
If the time is cumulatively added, the previous cumulative addition
Use the results as a guide to determine if the service life of the motor at that time is acceptable.
It is easily known.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a water supply pump control device according to the present invention. FIG. 1 shows an embodiment of the present invention, in which 1 is a pump, 2 is a motor for driving the pump 1, and 3 is a motor for converting the input three-phase power into three-phase AC power of an arbitrary frequency to enable the motor 2. Inverter for shifting drive control, 4 is a pressure sensor for measuring the pressure on the pump discharge side, 5 is a pressure sensor for measuring the pressure on the pump suction side, 6 is a control device for controlling water supply operation, 7 is a controller, 8 is a temperature sensor for detecting the temperature of the motor 1, and 9 is a warning device (a lamp, a buzzer, etc.) for notifying that the motor 2 has reached an estimated useful life (lifetime).

The output of the motor 2 at the rated rotation speed N _R is
The maximum water supply demand Q _M required for this water supply device, for example, b which is 70% of the water supply amount shown in FIG.
The water demand as the rated water amount _{Q R (= 0.7 × Q M} ) indicated by this one which is selected to correspond to the rated water amount Q _R, is variable speed controlled by an inverter 3, the pump 1 It is driven to rotate, pressurizes water supplied from a suction side pipe 13 connected to a water main 12, and discharges a pipe 14
The water is supplied to the water supply line 15 via the.

The inverter 3 is controlled by a rotation speed (frequency) signal N supplied from the controller 7 and functions to supply AC power of a frequency corresponding to the rotation speed (frequency) to the electric motor 2 to perform a variable speed operation.

The pressure sensor 4 functions to detect the pressure of water in the pipe 14 on the discharge side, and to input the discharge pressure Hout to the controller 7, and the pressure sensor 5 functions to input the pipe 1 on the suction side.
The function of detecting the pressure of the water in 3 and inputting the inflow (suction) pressure Hin to the controller 7 is as follows. On the other hand, the temperature sensor 8
Functions to detect the temperature of the electric motor 1 and input the detected temperature to the controller 7.

FIG. 2 is a detailed view of the controller 7, in which 71 is a central processing unit (CPU), 72 is a storage device (SRAM) having a backup power supply, and 73 is an input / output circuit (I
/ O) a and a pressure sensor 4,5 or we feed was signals,
Via the input / output circuit 73, the central processing unit 71 takes in the data representing the discharge pressure Hout and the inflow pressure Hin, and the signal supplied from the temperature sensor 8 is data representing the temperature t of the electric motor 1. Central processing unit 71
It is taken in.

The central processing unit 71 performs arithmetic processing based on these various data, outputs a rotation speed signal N to control the number of rotations of the electric motor 2 , and measures and accumulates (accumulates) the operation time. Processing such as addition) . And
Data representing the accumulated operation time is stored in a storage device 72 having a backup power supply so that the data does not disappear even when the power supply of the system is turned off. Further, when the central processing unit 71 determines that the accumulated operating time has reached the estimated life, the central processing unit 71 also executes a process of issuing a warning by the warning device 9.

Next, the operation of this embodiment will be described with reference to FIGS.
This will be described with reference to the flowchart shown in FIG. First, in FIG. 3, in a main process 30, after the power is turned on, the pump discharge side pressure Hout is lower than the starting pressure H3, and the pump inflow pressure H
in the running target pressure SH0 ejection outlet side control 40 if care is beyond the suction, the target pressure S pump inlet pressure Hin is suction
If H0 less adapted to perform a suction write-side control 50. After the power is turned on , a sequential time calculation process 90 is executed.

[0018] Figure 4 is a detail of the ejection outlet side control 40, the process examines the discharge-side pressure Hout, it ejection outcome target pressure H
If it is 0 or less running speed increasing control 60, when the discharge-side pressure Hout exceeds the ejection outcome target pressure H0 is adapted to perform the deceleration control 70.

[0019] Figure 5 is a detail of the intake write side control 50, this processing, if the pump inlet pressure Hin exceeds the pump-stop pressure Hsp, the pump inlet pressure Hin is suction write targets pressure S
H0 running Tei lever acceleration control 60 exceeds a deceleration control if the pump inlet pressure Hin is Re der less suction target pressure SH0 7
0 is executed. However , if the pump inflow pressure Hin is equal to or lower than the pump emergency stop pressure Hsp, the water
To abnormal reduction in hydraulic Dohon tube 12 is prevented, the pump
1 is an emergency stop .

FIG. 6 shows the details of the speed increasing control 60. In this processing, if the electric motor 2 and the pump 1 are stopped, the electric motor 2 and the pump 1 are soft-started from the minimum number of revolutions. > The processing for increasing the rotation speed of the machine 2 and the pump 1 is executed. At this time, the central processing unit 71, as long as the discharge-side pressure Hout is smaller than the ejection outcome target pressure H0, the rotational speed of the motor 2 above the rated speed N _R, in FIG. 11, for example The frequency signal N is controlled so as to reach the high-speed rotation speed N _{H as} shown above, and the water supply capacity exceeding the rating is exhibited.
Although the motor 1 having the rated rotation speed N _R is used, it is possible to sufficiently cope with the time zone in which the maximum water supply demand Q _M shown in FIG. 10 is required.

[0021] Figure 7 is a detail of the deceleration control 70, this process is less discharged water is flow - switch Fs (FIG. 1
Is not shown), the pump stop processing 80
Is executed, otherwise, a process of reducing the rotation speed of the electric motor 2 and the pump 1 is executed. FIG. 8 shows the details of the pump stop process. In this process, after the operation within the pump stop determination speed Ns is continued for about 2 minutes, the operation speed is reduced.
After the pressure is raised to Nst and sufficient water is stored in the pressure tank, a process of soft-stopping the electric motor 2 and the pump 1 is executed.

[0022] Figure 9 is a detailed time arithmetic processing 90, the process monitors the rotational speed signal N at all times, each time the motor 2 is ready to be operated beyond the rated speed N _R, the each time the operation time from exceeding the rated speed N _R (elapsed
Time) T measurement is started. Then, at this time, the temperature t of the electric motor 2 detected by the temperature sensor 8 is compared with a preset allowable maximum temperature tmax, and a coefficient n (n ( ΔT) to be added to the operation time T according to the deviation is added. n = 1, 2,
4,8 ... ... ...) changed, has become the integration time T _C a (≧ T) so as to Starring <br/> calculated.

Here, the allowable maximum temperature tmax is set according to the insulation specification of the electric motor 2. For example, in the case of an electric motor using an E type insulating material, the allowable maximum temperature tmax is set. Is set as tmax = 120 ° C
Has become . When the temperature t of the electric motor 2 becomes equal to or higher than the permissible maximum temperature tmax + 30 ° C., the electric motor 2 is immediately stopped and the operation of the pump 1 is stopped, so that an abnormal temperature rise due to the overload operation is prevented. Is to be prevented.

On the other hand, in parallel with this, the central processing unit 71 constantly monitors the accumulated time T _C, and when the accumulated time T _C reaches a preset reference time T _S (T _C ≧ T _S ), this is also reset.
Until a predetermined time T ₀ that is set because elapses, regardless of the water supply amount that is required at that time, as the rotational speed of the motor 2 is equal to or less than the rated rotational speed N _R, to output a frequency signal N You. Here, the predetermined time T ₀ As the motor 2
May be set so as to give a sufficient time for the temperature t to drop below the allowable maximum temperature tmax.

Next, the central processing unit 71 calculates the integrated time
Each time T _C is obtained, it is stored in storage device 72 by then.
The stored cumulative time TA, that is, the cumulative
By adding to the calculated been accumulated time T _C, determine the new <br/> accumulated time TA, monitors this, it motor 2
When the time to reach the useful limits, for example, it reaches 2 × 10 ⁴ h, the signal sent to the warning device 9, that perform processing for notifying it.

[0026] Therefore, according to this embodiment, despite using the electric motor 2 to 70% of the rated required rotational speed (output), fully corresponds to the maximum water supply demand Q _M, the request Can be ensured, and as a result, operation close to the rated output can be obtained on average, and the efficiency is greatly improved, so that the power consumption is reduced and the facility cost is sufficiently reduced. be able to.

If, for some reason, the time during which the electric motor 2 has been operated beyond the rated speed is extended for some reason, the electric motor 2 is operated in accordance with the elapsed time and the temperature of the electric motor 2. Since the motor 2 is returned to the rated operation, it is possible to prevent the occurrence of an abnormality in the motor 2 and, even at this time, the water supply operation is not stopped but the water supply amount is reduced. Since the water supply operation is continued, the reliability can be sufficiently maintained.

Further, according to this embodiment, an alarm is issued by accumulating the time during which the motor 2 has been operated at the rated speed or higher. At this time, the accumulated time is the length of time during which the electric motor 2 is overloaded.
Therefore, since it is possible to estimate whether or not the electric motor 2 has reached the service limit (lifetime) based on the length of the time, predetermined maintenance can be performed by the above-mentioned alarm, and the device is broken down and the water supply is stopped. Such a situation can be prevented from occurring, and the reliability can be further improved.

In the above embodiment, the case where the present invention is applied to a water supply device has been described. However, the present invention can also be applied to a compressor and a blower using an electric motor.

[0030]

According to the present invention, since the speed is increased by increasing the rotation speed by the inverter, the rated output corresponding to the water supply amount less than the maximum water supply amount (about 70% of the maximum water amount) is obtained. Since an electric motor can be selected, equipment costs can be sufficiently reduced, and the capacity of power supply equipment and the like can be reduced.

Further, according to the present invention, since the operation in the maximum efficiency state can be obtained for a long time on average, the efficiency is largely improved and energy saving is obtained, so that there is an effect that a low running cost can be achieved.

Further, according to the present invention, a motor having a rated output smaller than the required output is used, and the maximum demand is met by the rotation speed higher than the rated speed.
Although there is a possibility of operating time is long becomes an abnormality occurs at this time, in the present invention, response time that is operated beyond the rated
Integrating the Flip value, since this totalized value is returned to the rated operating conditions Once reaches a predetermined value, there is no possibility of occurrence of abnormality, it is possible to obtain sufficient reliability.

Furthermore , according to the present invention, the electric motor itself
If the temperature of the pump exceeds the maximum allowable
Not only can the motor be stopped, but it can be estimated that the motor has reached the end of its useful life (lifetime), so that a warning can be given beforehand, so that the maintenance time can be known, and the operation can be stopped by appropriate measures. Can be reliably avoided, so that the reliability can be further improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a feedwater pump control device according to the present invention.

FIG. 2 is an explanatory diagram of a controller according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a main process in one embodiment of the present invention.

FIG. 4 is a flowchart showing discharge-side control in one embodiment of the present invention.

FIG. 5 is a flowchart showing suction-side control in one embodiment of the present invention.

FIG. 6 is a flowchart showing speed increasing control in one embodiment of the present invention.

FIG. 7 is a flowchart showing deceleration control in one embodiment of the present invention.

FIG. 8 is a flowchart showing pump stop control in one embodiment of the present invention.

FIG. 9 is a flowchart showing a time calculation process in one embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a change in water supply demand.

FIG. 11 is a characteristic curve diagram of a pump.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pump, 2 ... Electric motor, 3 ... Inverter, 4, 5 ... Pressure sensor, 6 ... Control device, 7 ... Controller, 8 ... Temperature sensor, 9 ... Warning device, 12 ... Water main line, 13 ... Piping on suction side , 14 ... Discharge side piping, 15 ... Water supply line

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masao Yoshida 7-1-1, Higashi Narashino, Narashino City, Chiba Prefecture Inside the Narashino Plant, Hitachi, Ltd. JP-A-4-121470 (JP, A) JP-A-60-190191 (JP, A) JP-A-2-54390 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 15 / 00 F04B 49/00-49/10

Claims (4)

(57) [Claims] 1. An electric motor whose speed is controlled by an inverter.
And a pump that is rotated by this motor.
Pump according to the amount of water supplyButVariable speed driveAnd constant
The pump is allowed to operate while the conditions permit continuous overload operation.
It is always drivenWater pumpcontrolapparatusSo
The output frequency of the above inverter from the maximum water demand.
Pre-determined electric motor corresponding to the specified water supply amount
Control that can be controlled to be higher than the drive frequency of
Data control means and the inverter control means.
From when the motive begins to operate beyond the above drive frequency
Measurement means for measuring the value corresponding to the elapsed time of
Measured by the measuring means exceeds the preset value.
The output frequency of the inverter
Water supply characterized by being configured to set the frequency below
Pump control device. 2. An electric motor whose speed is controlled by an inverter, and a pump that is rotationally driven by the electric motor, wherein the pump is driven at a variable speed according to the amount of supplied water , and
The pump is operated for a long period of time while
When the motor is used, the service life of the motor is managed and displayed.
A water supply pump control device , wherein the output frequency of the inverter is controllable so as to be higher than a drive frequency of a predetermined electric motor corresponding to a predetermined water supply amount smaller than a maximum water supply demand amount. Control means; and accumulative timer means for accumulatively adding and counting the time during which the motor has been operated beyond the drive frequency by the inverter control means. Based on the result of measurement by the accumulative timer means, a service life limit of the motor is provided. The feedwater pump control device, characterized in that it is displayed. The method according to claim 3 wherein said gauge measuring means, to the extent the temperature of the electric motor itself is measured by the electric motor is high, the water supply pump control apparatus according to claim 1, wherein the elapsed time is measured as larger than actual value . 4. An electric motor whose speed is controlled by an inverter.
And a pump that is rotated by this motor.
Pump according to the amount of water supplyButVariable speed driveAnd constant
The pump is allowed to operate while the conditions permit continuous overload operation.
Although the motor is always running, the temperature of the motor itself is the maximum allowable temperature.
The above-mentioned pump shuts down for the first time due to excessive degree
I was put in a stateWater pumpcontrolapparatusSo
The output frequency of the above inverter from the maximum water demand.
Pre-determined electric motor corresponding to the specified water supply amount
Control that can be controlled to be higher than the drive frequency of
Data control means and the inverter control means.
From when the motive begins to operate beyond the above drive frequency
Measuring means for measuring a value corresponding to the elapsed time of
Temperature measuring means for measuring the temperature of the machine itself, and the measuring means
When the measured value exceeds a predetermined value set in advance
Is output from the inverter via the inverter control means.
Control to set the force frequency below the drive frequency.
On the other hand, the temperature of the motor itself by the temperature measurement means is allowed.
If the maximum temperature is exceeded, the pump will stop operating.
Pump control means for controlling
And a feed water pump control device.