JPS6073702A - Number of revolution controller - Google Patents

Abstract

PURPOSE:To automatically change a number of revolution to one in which no abnormality occurs and, at the same time, to make operation which satisfies a control target value possible, by adding a setting of number of revolution changing device equipped with a prescribed function. CONSTITUTION:A setting of number of revolution changing device 10 is added. This changing device 10 is equipped with a function which automatically changes the setting of number of revolution from a number of revolution set in an operation inhibiting area to another number of revolution outside the operation inhibiting area when the first mentioned number of revolution is set in the operation inhibiting area in facilities provided with the operation inhibiting area in which no operation is allowed because abnormality occurs when operation is made in the fixed area within a number of revolution control range. Moreover, the pressure output signal 7a of a pressure detector 7, flow rate output signal 8a of a flow rate detector 8, and output signal 9a of a number of revolution detector 9 are inputted into the changing device 10 as signals for judgement. Therefore, setting of number of revolution can be changed automatically to a number of revolution in which no abnormality occurs and, at the same time, operation which satisfies a control target value can be realized.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to the improvement of a rotation speed control device, and in particular, the invention relates to the improvement of a rotation speed control device, and in particular, the prohibition of operation where operation is not possible due to an abnormality occurring when operating in a certain region within the rotation speed control range. The present invention relates to a rotational speed control device that automatically corrects the rotational speed setting to a rotational speed outside the prohibited operation area when the rotational speed is set within the prohibited operation area in equipment having a prohibited operation area.

[Technical background of the invention and its problems]

Recently, machine rotation speed control has been widely adopted in all fields for the purpose of energy-saving operation.

FIG. 1 shows a system configuration diagram for controlling the rotational speed of a pump in order to keep the water distribution pressure within a constant range in a water supply facility. This is pump 2, which distributes water from pump well 1.
, an electric motor 3 for driving this pump 2, a rotation speed controller 4 for controlling the rotation speed of this electric motor 3, a pressure setting device 5 for setting a target pressure, and a pressure of this pressure setting device 5. a rotation speed calculator 6 that calculates the rotation speeds of the pump 2 and the electric motor 30 and sets the rotation speeds to the rotation speed controller 4;
a pressure detector 7 for detecting the pressure and flow rate of water distribution;
It is composed of a flow rate detector 8 and a rotation speed detector 9 that detects the rotation speed of the electric motor 3. Note that the pressure output signal 7a of the pressure detector 7 and the flow rate output signal 8a of the flow rate detector 8 are as follows.
It is input to the rotation speed calculator 6 and used to calculate the rotation speed. In addition, the rotation speed output signal 9a of the rotation speed detector 9
is input to the rotation speed controller 4 and used as a rotation speed feedback signal.

FIG. 2 shows a control method when operating the system according to the system configuration diagram shown in FIG. 1, and FIG. 3 shows the state at that time.

FIG. 2 shows a function 21 that reads process flow rate, pressure, and set pressure; a function 22 that calculates the set rotation speed so that the pressure is within a range based on these read signals;
Function 2 to set the calculated redundant rotation speed to the rotation speed controller
3. It is comprised of a function 24 for controlling the rotation speed of the electric motor to a set value using a rotation speed controller.

The process state at this time is shown in FIGS. 3 to 5, and the flow rate output signal 8a of the flow rate detector 8 changes depending on the demand amount. If constant pressure control is being performed at this time, the pressure output signal 7a of the pressure detector 7 will be within a certain range (between P+ + P2) as shown in FIGS. The rotational speed output signal 9a of the rotational speed detector 9 changes approximately in proportion to the change in the flow rate output signal 8a.

However, as the rotation speed controller 4, a converter using a switching element such as a thyristor is often used, and in this case, a harmonic current is generated. Further, the frequency of this harmonic current changes depending on the rotational speed in the case of a secondary excitation method such as a thyristor Cervius, for example.

On the other hand, converters using these switching elements often take a lagging current, and a phase advance capacitor is inserted to compensate for this lagging current. For this reason, harmonic current is added between the transformer actance and the conductance of the phase advance capacitor in the power supply system, and when the resonant frequency of the reactance and conductance matches the frequency of the harmonic current, parallel resonance occurs and harmonics are generated. The current is abnormally amplified.

Therefore, when resonance occurs, harmonic current flows abnormally, the power supply voltage waveform is distorted, flicker occurs in the lighting lamp, and other inconveniences occur, so it is not preferable to operate within the rotational speed range where resonance occurs.

Furthermore, if the mechanical system including the pump and electric motor is operated in a range where the resonance frequency and rotational frequency match, problems such as increased vibration will occur, so it is not desirable to operate in a rotational speed range that matches the resonance frequency.

Conventionally, even when these inconveniences occur, the engine is operated within the full rotational speed control range with emphasis on constant pressure control, or when these inconveniences occur, the engine is operated in a control mode that manually sets the rotational speed. Switching and setting of the rotational speed that would cause problems were avoided, which resulted in pressure not being at a constant value, resulting in unsatisfactory operation.

[Purpose of the invention]

Therefore, an object of the present invention is to set the rotation setting signal so that when the rotation speed is such that an abnormality occurs when the machine is operated according to the rotation speed setting signal, the rotation speed is not set at that rotation speed and the control target value is satisfied. An object of the present invention is to provide a rotation speed control device that corrects the rotation speed.

[Summary of the invention]

In a rotation speed control device, the present invention provides a rotation speed setting that is output by a rotation speed calculator when there is an operation prohibited area in which the operation cannot be performed because an abnormality occurs if the operation is performed within a one-leg region within the rotation speed control range. If the traffic light is in a no-driving area, take precautions to avoid driving in the no-driving area.
If the rotation speed enters the operation prohibited area in the speed increase direction (deceleration direction), first there is a function to set the minimum (-R: large) rotation speed in the operation prohibited area and check whether the process amount is within the range. A function to judge and, if the process amount is within a certain range, the minimum (maximum) of the prohibited operation area.
It is characterized by being equipped with a rotation speed setting correction device that has the function of setting the rotation speed and, on the other hand, the function of setting the maximum (minimum) rotation speed in the operation prohibited area if the process amount completely deviates from a certain range. This is a rotation speed control device.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to all the drawings. As an embodiment of the present invention, a system configuration diagram is shown in FIG. 6, in which the rotational speed of a pump is controlled in order to keep the water distribution pressure within a certain range in a water supply facility.

FIG. 6 shows the configuration diagram of FIG. 1 with a rotational speed correction device IO added thereto. This rotation speed correction device 10 is used in equipment having an operation prohibited area where operation is prohibited due to an abnormality occurring if the engine is operated within a certain range within the rotation speed control range, and when the rotation speed is set within the operation prohibited area. , the rotation speed setting is automatically corrected to a rotation speed outside the prohibited driving range.

Moreover, the pressure output signal 7a of the pressure detector 7, the flow rate output signal 8a of the flow rate detector 8, and the rotation speed output signal 9a of the rotation speed detector 90 are input to the rotation speed correction device as signals for determination.

FIG. 7 shows the functions of the system configuration diagram of FIG. 6. This is a function to read process flow rate, pressure and set pressure 21. A function 22 that calculates the set rotation speed so that the pressure is within a certain range based on these read signals;
Function 2 to determine whether this set rotation speed is a rotation speed that can be operated.
5. If the set rotation speed is an operable rotation speed, the calculated setting rotation speed is automatically adjusted by the rotation speed setting correction device as shown below. It is comprised of a function 23 for setting the corrected rotation speed in the rotation speed controller, and a function 24 for controlling the rotation speed of the electric motor so that it becomes the set value by the rotation speed controller.

If the function 25 that determines whether the set rotational speed is an operable rotational speed or not allows operation, the following procedure is performed.

That is, when the rotation speed setting signal enters the operation prohibited area, the function 26 first determines whether or not the set rotation speed is in the speed increasing direction. In this case, the function 27 ('28) sets the minimum (maximum) rotation speed in the prohibited operation range, the function 29 determines whether the pressure is within a certain range, and if the pressure is within a certain range, the first step is to start the operation. It consists of a function 27 (28) to set the minimum (maximum) rotation speed in the prohibited area, and a function 28 (27) to set the maximum (minimum) rotation speed in the prohibited area if the pressure deviates from a certain range. , this set rotation speed is set in the function 23.

The case of operation using the system configuration diagram of FIG. 6 will be explained with reference to FIGS. 8 and 9 which show the state.

In the process shown in FIG. 6, the purpose is to control the rotation speed of the pump 2 so that the pressure detection signal 7ak of the pressure detector 7 falls within a certain range (between p, , and P).

As a reminder, there is a rotational speed at which abnormality occurs in this process, and this rotational speed is assumed to be between N1 and N. Therefore, these rotational speeds N1 and N! During this period, pump 2 must never be operated at full capacity.

As shown in FIG. 6, the flow rate output signal 8a of the flow rate detector 8
changes depending on the amount demanded. Since constant pressure control is being performed at this time, the pressure output signal 7a of the pressure detector 7 is
As shown in the figure, it falls within a certain range (between Pr and P2). As the demand increases and the flow rate detection signal 8a of the flow rate detector 8 increases, the pressure gradually decreases, so the rotation speed calculator 6 gives a rotation speed increase command to the rotation speed controller 4. Electric motor 3 and pump 2 will speed up.

However, it is assumed that the lower limit N2 of the rotation speed in the operation prohibited region has been reached. If there is no prohibited driving area, there will be no problem if the speed is increased as is, but the speed cannot be increased as is. Therefore,
When the lower limit N2 of the rotation speed in this operation prohibited area is reached (A
The pressure output signal 7a of the pressure detector 7 is monitored while maintaining the rotation speed N2k, and when the pressure output signal 7a is about to deviate from the lower limit P2ffi of the constant pressure range (point B), the operation is prohibited. Upper limit of rotation speed N1'! i-Set (point C).

At this time, the rotation speed passes through the operation prohibited area, but it is for a short time so there is no problem with the total heat.

If the demand increases further, the rotational speed setting signal becomes a rotational speed outside the operation prohibited area (point D), so it is sufficient to operate at the calculated rotational speed.

The above explanation is for the case where the demand quantity increases, but the same can be done when the demand quantity decreases.

However, in this case, the lower limit N2 of the rotation speed needs to be read as the upper limit P1 of the rotation speed, and the lower limit P of the pressure needs to be read as the upper limit P1 of the pressure.

As explained above, according to this embodiment, the rotation speed in the prohibited operation range is set? Even if the engine is operated at a rotation speed outside the prohibited range, the pressure can always be kept within a certain range.

〔Effect of the invention〕

As explained above, according to the present invention, even if an abnormality occurs when the machine is operated according to the rotation speed setting signal, the rotation speed is automatically corrected to a value that does not cause the abnormality, and moreover, satisfies the control target value. You can drive as if

[Brief Description of the Drawings] Fig. 1 is a configuration diagram of a conventional device, Fig. 2 is a functional explanatory diagram of a conventional device, Figs. 3 to 5 are state explanatory diagrams of Fig. 2, and Fig. 6 is a diagram of the present invention. FIG. 7 is a functional diagram of FIG. 6, and FIGS. 8 and 9 are state diagrams of FIG. 7. ■...Pump well 2...Pump 3...Electric machine 4...Rotation speed controller 5...Pressure setting device 6...Rotation speed calculator 7...Pressure detector 7a
...Pressure output signal 8...Flow rate detector 8a...Flow rate output signal 9...Rotation speed detector 9a...Rotation speed output signal lO...Rotation speed setting correction device agent Patent attorney Rules Kensuke Chika (and 1 other person) Figure 1 Figure 2 Figure 5 Shakudo, h power. 27 h power j゛-foot control lI [l hei 1: Chikiyodan; installation mouth Toshiyuki 22 14, i. 23 'f is applied to the fixed rotation number control device. Fig. 3: 1 hour interval - Fig. 6 - Fig. 7

Claims (1)

[Claims] A machine that changes the process amount by changing the rotation speed, a drive machine for driving this machine, a process amount setting device for setting the process t to a predetermined value,
A process amount detector for detecting a process amount, and a rotation for comparing the output signal of the process amount setting device with the output signal of the process amount detector and converting the output signal into a rotation speed setting signal that makes both equal. a number calculator, a rotation speed controller for changing the rotation speed of the drive machine to a predetermined process amount based on an output signal of the rotation speed calculator, and a rotation speed controller for detecting the rotation speed of the drive machine. In a rotation speed control device consisting of a rotation speed detector, if there is an operation prohibited area where operation cannot be performed because an abnormality will occur if the operation is performed within a certain range within the rotation speed control range, the rotation speed calculator will output an output signal. If the rotation speed setting signal to be input is within the operation prohibited area, then
When the rotational speed enters the operation prohibited area in the acceleration direction or deceleration direction, a function first sets the minimum or maximum rotational speed of the operation prohibited area, and a function determines whether the process amount is within a certain range. and, if the process amount is within a certain range, the minimum or maximum rotation speed of the prohibited operation area is set as is, and on the other hand, if the process amount deviates from the specified range, the maximum or minimum rotation speed of the prohibited operation area is set. A rotation speed control device comprising a rotation speed setting correction device having a function of setting a rotation speed.