JP2004169666A - Operation control method and operation control device of pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately operate a pump for pumping by preventing over rotation speed driving of a motor. <P>SOLUTION: The motor 2m of the pump 2 for pumping is driven by pressure constant control. When the rotation speed of the motor 2m exceeds a set rotation speed by the pressure constant control, the driving control of the motor 2m is switched from the pressure constant control to rotation speed constant control to suppress over rising of the rotation speed of the motor 2m. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an operation control method and an operation control device for a pump used for pumping well water or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in remote islands and remote mountainous areas, well water is pumped up by a pump (water supply pump) and supplied from one or more water taps (faucet).
[0003]
Similarly, when pumping various liquids such as water and oil from wells and tanks and supplying them from valves such as water taps at one or a plurality of locations, the same pumping as the pump for pumping well water described above is used. Pump is used.
[0004]
In these pumps for pumping, brushless DC motors are frequently used as driving motors in terms of efficiency and the like (for example, see Patent Document 1).
[0005]
Further, a motor for driving this type of pump is conventionally driven by constant pressure control by feedback control (following servo control) such as PID control so as to keep the discharge pressure of the pump constant (for example, Patent Documents 1, 2, and 3).
[0006]
[Patent Document 1]
JP-A-11-210670 (pages 1-3, FIG. 1)
[Patent Document 2]
JP-A-60-79197 (page 1-2, FIG. 1)
[Patent Document 3]
JP-A-54-142602 (pages 1-3, FIGS. 6, 7)
[0007]
[Problems to be solved by the invention]
When the pump pressure is controlled to be constant by the constant pressure control as in the conventional case, for example, when all the valves are opened and the discharge pressure of the pump suddenly decreases, the motor is continuously rotated at an overspeed. In this state, the motor is continuously driven to rotate at full speed, causing abnormal heat generation and failure.
[0008]
On the other hand, in order to avoid the above-mentioned full rotation drive, if the motor is driven by the rotation speed constant control and the rotation speed of the motor is kept constant, it is possible to cope with the fluctuation of the discharge pressure due to the load fluctuation. However, for example, when the number of opening valves is small, there is a problem that the discharge pressure of the pump becomes excessive and the pump or a water supply (liquid supply) pipe is damaged.
[0009]
Even when there is only one valve, the same problem as described above occurs due to a change in the open state (amount).
[0010]
Next, it is conceivable to operate the pump by controlling the suction pressure to be constant instead of the discharge pressure by the constant pressure control, but also in this case, for example, the suction pressure required for pumping the well water increases the liquid level of the well. (Water surface) varies depending on the level, and the same problem as described above occurs.
[0011]
Similar problems occur when operating not only the pump for pumping well water but also the pump for pumping various liquids.
[0012]
SUMMARY OF THE INVENTION It is an object of the present invention to prevent a motor from rotating excessively and to appropriately operate this kind of pump for pumping.
[0013]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a pump operation control method according to claim 1 drives a pumping pump motor by constant pressure control, and the constant pressure control causes the motor rotation speed to exceed the set rotation speed. When it becomes higher, the drive control of the motor is switched from the constant pressure control to the constant rotation speed control to suppress an excessive increase in the rotation speed of the motor.
[0014]
Therefore, in the pump for pumping, usually, the motor is driven under constant pressure control so that the discharge pressure or the suction pressure is constant.
[0015]
Then, due to the so-called load fluctuation on the discharge side and the suction side, in the drive of the constant pressure control, the rotation speed of the motor becomes higher than the set rotation speed. The control is switched to the rotation speed constant control, and an excessive increase in the rotation speed of the motor is suppressed.
[0016]
Therefore, this type of pump for pumping is properly operated while preventing the motor from over-rotating.
[0017]
According to a second aspect of the present invention, there is provided a pump operation control method, wherein the pumping pump motor is driven by a constant pressure control so that the discharge pressure of the pump becomes a set pressure, and the rotation of the motor is controlled by the constant pressure control. When the number of revolutions becomes higher than the set number of revolutions, the drive control of the motor is switched from the constant pressure control to the constant number of revolutions control so that the number of revolutions of the motor becomes the set number of revolutions. When the discharge pressure of the pump becomes higher than the set pressure, the drive control of the motor is switched back from the constant rotation speed control to the constant pressure control.
[0018]
Therefore, in the case of the second aspect, in the pump for pumping, the motor is normally driven under constant pressure control so that the discharge pressure thereof becomes the set pressure.
[0019]
During the driving of the constant pressure control, for example, when the load fluctuation (overload fluctuation) on the discharge side due to the opening of all the valves described above occurs and the rotation speed of the motor becomes higher than the set rotation speed, the motor is started. The drive control is switched from the constant pressure control to the constant rotation speed control, the rotation speed of the motor is regulated to the set rotation speed, and an excessive increase in the rotation speed is suppressed.
[0020]
Further, during this rotation speed constant control, when the load state on the discharge side changes and the discharge pressure of the pump becomes higher than the set pressure, the drive control of the motor is returned to the constant pressure control.
[0021]
Therefore, this kind of pump for pumping can be more appropriately operated according to the load state on the discharge side.
[0022]
Furthermore, a pump operation control method according to a third aspect is characterized in that the motor of the pump for pumping of the first and second aspects is a brushless DC motor.
[0023]
Next, the operation control device for a pump according to claim 4 includes a means for measuring a discharge pressure of the pump for pumping,
Means for measuring the number of revolutions of the pump motor;
A drive control unit that drives the motor based on the measurement results of the discharge pressure and the number of rotations,
In this drive control unit,
Means for arbitrarily driving a pump motor under constant pressure control based on the measurement result of the discharge pressure so that the discharge pressure is constant;
When the measured rotation speed of the motor exceeds the set rotation speed and rises to the upper limit rotation speed by the constant pressure control, the drive control of the motor is switched from the constant pressure control to the constant rotation speed control to measure the rotation speed. Means for driving the motor under constant rotation speed control based on the result so that the rotation speed of the motor becomes the set rotation speed;
Means for switching back the motor drive control from the constant rotational speed control to the constant pressure control when the measured discharge pressure of the pump rises to the upper limit pressure higher than the set pressure by the constant rotational speed control. It is.
[0024]
Therefore, it is possible to provide a specific operation control device that realizes the operation control method of the second aspect.
[0025]
The motor of the pump for pumping is preferably a brushless DC motor.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
As shown in the configuration diagram of the operation control device of the pump in FIG. 1, a pump 2 for pumping is installed near a well 1, and this pump 2 includes a pump body 2p and a motor 2m for driving the pump body 2p. Here, the motor 2m is a brushless DC motor.
[0027]
When the motor 2m is driven and the pump 2 is operated, the water 3 of the well 1 is drawn by the suction and discharge of the pump body 2p based on the rotation of the rotor of the motor 2m, as shown by the arrow line in the figure. The water is pumped through the suction pipe 4 and discharged from the pump body 2p to the water supply pipe 5.
[0028]
Further, the water 3 discharged to the water supply pipe 5 is sent to valves (water taps) provided at one or more locations of the water supply pipe 5 to be supplied (distributed).
[0029]
Next, a flow meter 6 and a pressure sensor 7 are provided near the discharge side of the pump body 2, the flow meter 6 measures the discharge flow rate of the pump 2, the pressure sensor 7 measures the discharge pressure of the pump 2, The sensor 7 is a unit for measuring the discharge pressure of the pump 2.
The flow meter 6 and the pressure sensor 7 may be built in the pump 2.
[0030]
Then, the measurement outputs of the flow meter 6 and the pressure sensor 7 are supplied to the drive control unit 8 of the motor 2m.
[0031]
The drive control unit 8 is built in, for example, the motor 2m. A temperature sensor 9 attached to the case measures the temperature of the motor 2m, and the measured output is supplied to the drive control unit 8.
[0032]
Although a dedicated PG sensor or the like may be provided as a means for measuring the number of rotations of the motor 2m, a Hall element sensor (Hall IC) 10 serving as a rotation position sensor of the motor 2m is provided here. A means for counting the number is formed, and the measurement output of the sensor 10 whose pulse interval changes according to the rotation speed of the motor 2m is supplied to the drive control unit 8 as the measurement output of the rotation speed of the motor 2m.
[0033]
The drive control unit 8 is formed as shown in the circuit block diagram of FIG. 2, and the measurement output (measurement result) of the flow meter 6 and the sensors 7, 9, 10 every moment is digitally converted by the A / D converter 11. The data is converted into data and taken into the controller 12 having a microcomputer configuration.
[0034]
The controller 12 has the following units (i) to (iii) formed by software based on a preset control program.
(I) A means for driving the motor 2m under constant pressure control based on the measurement result of the discharge pressure of the pump 2 so that the discharge pressure becomes constant. (Ii) The measured rotation speed of the motor 2m by constant pressure control. When the rotation speed exceeds the set rotation speed and rises to the upper limit rotation speed, the drive control of the motor 2m is switched from the constant pressure control to the constant rotation speed control, and based on the measurement result of the rotation speed of the motor 2m, Means for driving the motor 2m by the constant rotation speed control so that the rotation speed becomes the set rotation speed (iii) The measured discharge pressure of the pump 2 rises to the upper limit pressure higher than the set pressure by the constant rotation speed control. Means for switching back the drive control of the motor 2m from the constant rotation speed control to the constant pressure control.
Incidentally, the constant pressure control and the constant rotation speed control are feedback control (following servo control) such as PID control based on the discharge pressure of the pump 2 and the rotation speed of the motor 2m, and the PWM formed by these controls. The motor driver 13 supplies an on-current having a pulse waveform corresponding to the drive pulse to the motor 2m by a motor drive pulse (duty output) having a waveform, and controls the drive of the motor 2m.
[0036]
In addition, the controller 12 also has a means for starting and stopping the pump 2 in addition to the means (i) to (iii) described above.
[0037]
Then, the measurement results of the flow meter 6 and the temperature sensor 9 are sent to an abnormality monitoring unit 14 in the controller 12, and the monitoring unit 14 determines the discharge flow rate of the pump 2 based on the measurement results of the flow meter 6 and the temperature sensor 9. When the heat generation of the motor 2m is monitored and an abnormality in the discharge flow rate or overheating due to the abnormal heat generation of the motor 2m is detected, the motor driver 13 is instructed to stop driving, the driving of the motor 2m is stopped, and the pump 2 is stopped.
[0038]
Next, specific drive control of the motor 2m by the drive control unit 8 will be described.
First, the set pressure Pa is set to an appropriate pressure in the range of 16 m to 24 m in terms of water pressure, and the starting pressure Ps before operation is the set pressure -4 m in terms of water pressure.
[0039]
In order to prevent hunting of control switching, the upper limit pressure Pb is set to a set pressure +0.1 m in terms of hydraulic pressure.
[0040]
Next, the set rotational speed Ra is 3500 rpm, and the upper limit rotational speed Rb is set to the set rotational speed + 10 rpm in order to prevent hunting of control switching.
[0041]
Then, when the operation of the pump 2 is started by pressing a start button (not shown), the means for starting the pump 2 is operated, and the motor driver 13 outputs the three-phase current (motor current) having the maximum pulse width of the PWM control to the motor. The motor is sequentially supplied to the windings of each phase of 2 m to generate a rotating field and start the motor 2 m.
[0042]
After starting of the motor 2m, as shown in the flow chart of the drive control of the Figure 3, the process proceeds from step S ₁ to step S _2, the feedback control of preferentially pressure constant control is performed, via step S ₃ Step by moving to S _4, as the discharge pressure of the pump 2 becomes the set pressure Pa, the motor current is PWM controlled.
[0043]
Then, the process returns to step _{S 1} through step _{S 5} from step _{S 4,} usually, the loop control in step _S 1 to S _5, the pump 2 is operated at constant pressure control.
[0044]
Next, for example, when all valves of the water supply pipe 5 are opened to cause load fluctuation on the discharge side of the pump 2 and the discharge pressure decreases, the rotation speed of the motor 2m increases to compensate for the pressure decrease.
[0045]
Then, the rotational speed of the motor 2m becomes higher than the set rotational speed Ra, reaches the upper limit rotational speed Rb, proceeds from step S ₃ to step S _6, the drive control of the motor 2m is the rotational speed constant control from the pressure constant control Switch.
[0046]
In this case, the process proceeds to step S ₄ from step S ₆ through step S _7, as the rotation speed of the motor 2m is set rotational speed Ra, the motor current is PWM controlled.
[0047]
Until the discharge pressure rises to the upper limit pressure Pb, the pump 2 is operated with the rotation speed constant control by the loop control of steps S ₁ , S ₆ , S ₇ , S ₄ , and S ₅ .
[0048]
Therefore, even if a load change (overload change) occurs, the rotation speed of the motor 2m is regulated to the set rotation speed and the rise is suppressed, and an abnormal increase in the rotation speed of the motor 2m is prevented.
[0049]
Next, reduces the number of valves of unplugging state, the discharge pressure by the rotation speed constant control becomes higher than the set pressure Pa, reaches the upper limit pressure Pb, returns from step S ₇ to step S _1, at this time, step by moving from S ₁ to step S _2, the drive control of the motor 2m is switchback to the pressure constant control from the rotational speed constant control.
[0050]
Then, until the rotational speed of the motor 2m to rise again to the upper limit rotational speed, the loop control step S ₁ to S _5, the pump 2 is operated at constant pressure control.
[0051]
Therefore, even if a load fluctuation on the discharge side of the pump 2 occurs, the motor 2m does not over-rotate, preventing a failure due to abnormal heat generation of the motor 2m, and is extremely safe. The pump 2 can be appropriately operated in combination with the constant control.
[0052]
When the rotational speed of the motor 2m rises by the hysteresis from the set rotational speed Ra and reaches the upper limit rotational speed Rb, the pressure is switched from the constant pressure control to the constant rotational speed control of the set rotational speed Ra, and the discharge pressure is set to the set pressure Pa. When the hysteresis further increases and reaches the upper limit pressure Pb, the control is switched back from the constant rotation speed control to the constant pressure control of the set pressure Pa, so that the hunting of the switching of the drive control of the motor 2 does not occur.
[0053]
FIG. 4 shows, for example, changes over time in the discharge pressure of the pump 2 and the rotation speed of the motor 2m due to the load fluctuation.
[0054]
In the figure, a solid line A indicates a change in the discharge pressure of the pump 2, a solid line B indicates a change in the number of revolutions of the motor 2m, and a thick solid line C indicates the drive control of the motor 2m started at t _S at t ₁ It switched to the rotation speed constant control from the pressure constant control, when it is switchback pressure constant control from the rotational speed constant control at t _2, illustrating a control state (operating state).
[0055]
Further, the flow rate and the pressure in the operating state of the pump 2 by the drive control of FIG. 4 indicate, for example, the relationship indicated by the solid line d in FIG.
[0056]
Next, in order to surely prevent the hunting, the condition that the rotation speed and the discharge pressure are equal to or higher than the upper limit rotation speed Rb and the upper limit pressure Pb for a certain period of time (for example, 5 seconds) is set in practice. It is preferable to switch from pressure constant control to rotational speed constant control and vice versa.
[0057]
In the above-described embodiment, the pressure sensor 7 is provided on the discharge side of the pump 2. However, the pressure sensor 7 is provided on the suction side of the pump 2, and the motor is operated in accordance with a change in suction pressure due to a change in the liquid level of the well 1. The 2 m drive control may be switched from the constant pressure control to the constant rotation speed control and vice versa.
[0058]
The present invention can be similarly applied not only to wells but also to pumps for pumping various liquids such as water and oil from tanks and the like.
[0059]
At this time, the pump motor is not limited to the brushless DC motor, and the feedback control of the constant pressure control and the constant rotation speed control is not limited to the PID control.
[0060]
Further, the set pressure Pa, the upper limit pressure Pb, the set rotation speed Ra, the upper limit rotation speed Rb, and the like may be set appropriately according to the capacity of the motor 2m, the conditions of the well, and the like.
[0061]
【The invention's effect】
The present invention has the following effects.
First, in the case of the pump operation control method of claim 1, the pump 2 for pumping is normally driven by the motor 2m under constant pressure control so that the discharge pressure or the suction pressure is constant, and the discharge side and Due to the so-called load fluctuation on the suction side, the rotation speed of the motor 2m becomes higher than the set rotation speed in the drive of the constant pressure control, and when the motor is over-driven, the drive control of the motor 2m is changed from the constant pressure control to the constant rotation speed. By switching to control, an excessive increase in the rotation speed of the motor 2m can be suppressed.
[0062]
Therefore, it is possible to prevent the motor 2m from being over-rotated and to appropriately operate this kind of pump 2 for pumping.
[0063]
Further, in the case of the pump operation control method according to the second aspect, a load fluctuation (overload fluctuation) on the discharge side due to, for example, opening of all valves occurs during driving of the constant pressure control of the motor 2m of the pump 2. When the rotational speed of the motor 2m becomes higher than the set rotational speed, the drive control of the motor 2m is switched from the constant pressure control to the constant rotational speed control, and the rotational speed of the motor 2m is regulated to the set rotational speed, and the rotational speed of the motor 2m is increased. The rise can be suppressed.
[0064]
Further, during this rotation speed constant control, when the load state on the discharge side changes and the discharge pressure of the pump 2 becomes higher than the set pressure, the drive control of the motor 2m can be returned to the constant pressure control.
[0065]
Therefore, this kind of pump 2 for pumping can be more appropriately operated according to the load condition on the discharge side.
[0066]
In the pump operation control method according to claims 1 and 2, the motor 2m is preferably a brushless DC motor.
[0067]
Next, in the case of the operation control device for a pump according to claim 4, it is possible to provide an operation control device having a specific configuration for realizing the operation control method according to claim 2.
[0068]
In the pump operation control device according to the fourth aspect, the motor 2m is preferably a brushless DC motor.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a configuration according to an embodiment of the present invention.
FIG. 2 is a detailed circuit block diagram of a part of FIG. 1;
FIG. 3 is a flowchart for explaining the operation of FIG. 2;
FIG. 4 is a control characteristic diagram of the pump of FIG. 1;
FIG. 5 is a relationship diagram between a flow rate and a pressure of the pump in FIG. 1;
[Explanation of symbols]
2 Pump for pumping 2 m Pump 7 Pressure sensor 8 Drive control unit Pa Set pressure Pb Upper limit pressure Ra Set rotation speed Rb Upper rotation speed

Claims (5)

The pump motor for pumping is driven by constant pressure control,
By the constant pressure control, when the rotation speed of the motor becomes higher than a set rotation speed, the drive control of the motor is switched from the constant pressure control to the constant rotation speed control,
An operation control method for a pump, wherein an excessive increase in the rotation speed of the motor is suppressed. The pump motor for pumping is driven by constant pressure control so that the discharge pressure of the pump becomes a set pressure,
By the constant pressure control, when the rotation speed of the motor becomes higher than a set rotation speed, the drive control of the motor is changed from the constant pressure control so that the rotation speed of the motor becomes the set rotation speed. Switch to constant rotation speed control,
When the discharge pressure of the pump becomes higher than the set pressure by the rotation speed constant control, the drive control of the motor is switched back from the rotation speed constant control to the pressure constant control. Pump operation control method. 3. The pump operation control method according to claim 1, wherein a motor of the pump for pumping is a brushless DC motor. Means for measuring the discharge pressure of the pump for pumping;
Means for measuring the number of rotations of the pump motor,
A drive control unit that drives the motor based on the measurement result of the discharge pressure and the number of rotations,
In the drive control unit,
Means for driving the motor of the pump under the pressure constant control, based on the measurement result of the discharge pressure, so that the discharge pressure is constant,
By the constant pressure control, when the measured rotational speed of the motor exceeds the set rotational speed and rises to the upper limit rotational speed, the drive control of the motor is switched from the constant pressure control to the constant rotational speed control, Means for driving the motor under the rotation speed constant control, based on the measurement result of the rotation speed, so that the rotation speed of the motor becomes the set rotation speed;
When the measured discharge pressure of the pump increases to the upper limit pressure higher than the set pressure by the rotation speed constant control, the drive control of the motor is switched from the rotation speed constant control to the pressure constant control. An operation control device for a pump, comprising a return means. The operation control device for a pump according to claim 4, wherein the motor of the pump for pumping is a brushless DC motor.

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