JPS63253894A - Controller for motor - Google Patents

Abstract

PURPOSE:To reduce the variation of the rotational speed of a motor at the time of the abnormal state of a controller, by switching the command value of an inverter to a setting unit storing the output value of the controller, when the abnormal state of the output of the controller is detected. CONSTITUTION:When an abnormal state is generated on a controlling circuit 1, detection signal 3a, or a controller 21, then the output 21a of the controller 21 is varied. The variation of the output 21a in this case is quickly performed in any abnormal state, because the responding speed of the controller 21 is quickly performed. However, because there is a delay element 20, the variation of input to an inverter 6 and input to a setting unit 8 is slowly performed. Accordingly, by an abnormal state detector 10, the abnormal state of the output 21a of the controller 21 is quickly detected, and the input to the inverter 6 is to be switched to the output of the setting unit 8, and so the variation of the input to the inverter 6 is reduced also at the time of the abnormal state of the controlling circuit, and the variation of the rotational speed of a motor is also reduced.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a secondary i-circulation pump drive motor of a fast breeder reactor driven by an inverter and an internal pump drive machine of a boiling water reactor. This relates to control devices such as the following.

(Prior Art) Fig. 3 shows a conventional control device. 1 is an upstream control circuit whose output is the speed reference of the motor, 2 is a speed detector that detects the rotational speed of the motor, and 3 is a speed detector 2. 4 is an adder that performs subtraction between the speed reference and the speed detection signal, and 5 is the speed controller consisting of an integral controller, a proportional controller, etc. Adder 4
The frequency reference 5a of the inverter 6 is output based on the output of the inverter 6.

The switching device 7 is a sequence circuit that outputs signal switching and condition signals, and the automatic/manual switching signal is sent from the automatic/manual switching device 9 as a switching signal, and also monitors the output level of the speed controller 5 to detect abnormalities. A switching signal is input from an abnormality detector 1O which outputs a switching signal to the switching device 7 when detected. When the frequency reference 5a is normal during automatic operation, the setting device 8
The frequency reference 5a is inputted through the switch 7, and the output of the setting device 8 is made to follow the frequency reference 5a. The condition for the follow-up operation is when the follow-up command signal 7a from the switch 7 is input. That is, this is the case when the frequency reference 5a is normal during automatic operation, and in FIG.
This is the case when the contacts are closed. When the frequency reference 5a becomes abnormal, the conditions of the switch 7 change due to the switching signal from the abnormality detector 10 and the follow-up command signal 7a is no longer input, so the setter 8 stops tracking and changes the output to the follow-up command signal. 7a
is held at the value immediately before it disappears. After the follow-up command signal 7a disappears, the setting device 8 is controlled by the increase/decrease setting device 11.
This is a device that allows the output to be changed, and is commonly used as a setting device. The setting device 8 has an analog quantity storage element, and converts the input analog quantity of the frequency reference 5a into a digital quantity in order to eliminate the attenuation of the stored quantity over time, and further converts the digital quantity into an analog quantity. Since the data is stored in digital quantities, there is no attenuation due to time.

12 is an electric motor driven by the inverter 6, and 13 is a pump driven by the electric motor 12.

As mentioned above, in automatic operation, the speed controller 5 controls the motor 1 to the rotational speed reference value, which is the output of the upstream control circuit 1.
The two rotational speeds are controlled to match. In that state, speed controller 5. When the frequency reference 5a becomes abnormal due to an abnormality in the speed detector 2° converter 3 and adder 4 or the upstream control circuit, the frequency reference input to the inverter 6 is the frequency reference 8a output from the setting device 8. Therefore, until the increase/decrease setting device 11 is operated, the frequency reference input to the inverter 6 is a value corresponding to the frequency reference 5a immediately before the abnormality is detected. By performing switching in the event of an abnormality in this way, even if the control circuit is abnormal, the motor continues to operate as much as possible, thereby increasing the reliability of the system. Note that even if the inverter 6 and the electric motor 12 become abnormal, the output 5a of the speed controller 5 becomes abnormal as described above.
Since it is impossible to continue operation even if an abnormality is detected and switching is performed, and a protective operation cannot be performed by other detection, abnormalities in the inverter and electric motor will not be dealt with here.

(Problems to be Solved by the Invention) 'In the case of a secondary main circulation pump drive motor of a fast breeder reactor or an internal pump drive motor of a boiling water reactor, in which the conventional control device shown in Fig. 3 is used, The rotational speed of the electric motor changes slowly, and rapid changes in the rotational speed are considered undesirable. This is because, in the case of a secondary main circulation pump, a sudden change in the rotational speed of the electric motor puts thermal stress on the circulation system including the reactor, and in the case of an internal pump, the flow rate of the reactor coolant is reduced. This is because changes can lead to sudden changes in reactor output.

Therefore, the response speed of the speed controller 5 is also slow. - Although it is sufficient that the follow-up speed of the force setter 8, that is, the time it takes for the frequency reference 8a to match the frequency reference 5a, is slow, the follow-up speed is comparatively faster than manufacturing restrictions. If the following speed is increased, the frequency reference 8a, which is the output of the setting device 8, will also change between the time an abnormality is detected and the switching is performed, and the rotational speed of the motor will change before and after the abnormality occurs. As mentioned above, if the response speed of the speed controller 5 is slow, the frequency reference 5a will also change slowly when the speed detector 2, converter 3, and upstream control circuit 1 are abnormal, so when an abnormality is detected, the motor This means that the rotation speed has changed significantly. Furthermore, due to an abnormality in the speed controller 5, the frequency reference 5
If a suddenly changes, the frequency reference input to the inverter will change rapidly until an abnormality is detected and switching is performed.

As described above, conventional control devices have the disadvantage that the rotational speed of the motor changes significantly when the control circuit is abnormal.

Therefore, it is an object of the present invention to provide a control circuit for an electric motor in which the change in the rotational speed of the electric motor is reduced even when the control circuit is abnormal.

[Structure of the invention]

(Means for Solving the Problems) FIG. 1 shows a control circuit for an electric motor according to the present invention. Paying attention to the fact that the response speed of the control system is slow as described above, the delay element 20 is connected to the output of the controller 21, and the response speed of the control system is determined by the response speed of the controller 21 and the delay element 20.
In combination with this, the response speed is as slow as the conventional one.

Since the delay element 20 is present, the response speed of the controller 21 is faster than that of a conventional controller. Further, the frequency reference input to the setting device 8 is assumed to be the output 20a of the slow element 20.

(Function) When the control circuit is normal during automatic operation, the output of the controller 21 passes through the delay element 20 and further via the switching device 7, and is given to the inverter 6 as a frequency reference. When an abnormality occurs in the upstream control circuit 1, the detection signal 3a, or the controller 21, the output 21a of the controller 21 changes. 21a at this time
Since the response speed of the controller 21 is fast, the change in is a fast change in any of the abnormal cases mentioned above. However, delay element 2
0, the input to the inverter 6 and the input to the setting device 8 change slowly. Therefore, the abnormality detector 10 quickly detects an abnormality in the output 21a of the controller 21 and switches the input to the inverter 6 to the output of the setting device 8, so the input to the inverter 6 does not change even when the control circuit is abnormal. Become smaller, i! ! 1! Changes in the rotational speed of the II machine will also be small.

(Embodiment) Fig. 2 shows an embodiment of the present invention. Fig. 2 is a diagram in which the delay element 20 described in Fig. 1, which shows the present invention, is added to Fig. 3, which shows a conventional control device. be. The speed controller 30 is the first
Like the controller 21 in the figure, the response speed is faster than that of the speed control lI5 in FIG.

In the embodiment of FIG. 2, as explained in FIG. 1 showing the present invention, the upstream control circuit 1, the speed detector 2. When an abnormality occurs in the converter 3 or the speed controller 30, the abnormality is detected by the abnormality detector 1G and the input to the inverter 6 is delayed to output 2 of the element 20.
0a to the output of the setting device 8a. When an abnormality occurs, the output 30a of the speed controller 3o, that is, the input of the abnormality detector, changes quickly, but the change in the output 20a of the delay element 20 is slow, so the change in the output 8a of the setting device 8 is also slow. This makes it possible to reduce changes in the rotational speed of the electric motor.

As mentioned above, the embodiment shown in FIG. 2 has the advantage that the change in the rotational speed of the motor can be reduced in response to abnormalities in the control circuit.

The embodiment shown in FIG. 2 shows a rotational speed control system that detects the rotational speed of the electric motor and controls the rotational speed of the electric motor. In an internal pump for a water reactor, a flow rate control system may be used that detects the flow rate of reactor coolant and controls the flow rate.

〔Effect of the invention〕

As described above, the present invention has the effect of reducing the change in the rotational speed of the motor even in the event of an abnormality in the control circuit. For example, if used in the secondary main circulation pump drive motor system of a fast breeder reactor, the effect of changes in the rotational speed of the electric motor, that is, the rotational speed of the pump, can be reduced. The stress can be reduced, and if used in the internal pump drive motor system of a boiling water reactor, the effect of preventing sudden changes in reactor output can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the electric motor control device of the present invention, and FIG.
The figure is a block diagram showing an embodiment of the present invention, and FIG. 3 is a block diagram of a conventional electric motor control device. 1... Upstream control circuit 2... Speed detector 3...
・Conversion Jl14...Adder 5.30...Speed controller 5a, 8a, 20a, 21a, 30a-Frequency reference 6.
...Inverter 7...Switcher 7a...Following command signal 8...Setting device 9...Auto/manual switch 10...Abnormality detector 11...Increase/decrease setting #112
...Electric motor 13...Pump 20...
Delay element 21...controller

Claims (1)

[Claims] a controller that controls the rotational speed of the electric motor; an inverter that operates using the output of the controller as a frequency reference; an electric motor that is driven by the output of the inverter; In a device that is equipped with a setting device that stores memory and is configured to switch the inverter command value to the output of the setting device when an abnormality in the output of the controller is detected, there is a delay factor in the output of the controller. A control device for an electric motor, characterized in that the setting device stores the output of the delay element to reduce changes in the rotational speed of the motor when a control circuit including the controller is abnormal.