JPH11352276A - Variable voltage and variable frequency power source for recirculating pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously operate recirculating pumps by quickly switching the control system to a standby system during anomaly occurrence, such as over-voltage due to smoothing capacitor in a control program of a velocity controller and the semiconductor power converter. SOLUTION: A variable voltage and variable frequency power source 16 for a recirculating pump consists of a semiconductor power converter 17 of a voltage-type inverter provided with a smoothing capacitor 20 and a velocity controller 18. By providing a plural control systems of the velocity controllers 18, redundancy is taken and a protective circuit 30 which continuously operates the recirculating pump 1 is provided so that the anomaly in the variable voltage and variable frequency power source 16 is detected and the control system of the velocity controller 18 is switched from an operation system 31 to a standby system 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable voltage variable frequency power supply for driving a recirculation pump for a reactor coolant, and more particularly to a variable voltage variable frequency power supply in which the control state of the variable voltage variable power supply becomes abnormal. The present invention relates to a variable voltage variable frequency power supply device for a recirculation pump that continues operation without stopping a recirculation pump.

[0002]

2. Description of the Related Art A recirculation pump for a core coolant used in a nuclear reactor of a nuclear power plant, and a variable voltage variable frequency power supply as a drive power supply for controlling the speed of the pump are described below.
As shown in the longitudinal sectional view of FIG. 9, the recirculation pump 1 with a built-in reactor is installed at the bottom of the reactor pressure vessel 3 in the pump casing 2 and circulates the core coolant to reduce the flow rate. Reactor power is controlled by changing it.

[0003] Inside the pump casing 2, a pump impeller 6 is attached to the tip of a pump shaft 5 integrated with the motor rotor 4, and a pump diffuser 7 is arranged around the pump impeller. Upper journal bearing 8
And a lower journal bearing 9 rotatably supported.

Further, a motor stator 10 and a stator winding 11 are provided inside the pump casing 2, and a motor terminal box 12 connected to the stator winding 11 is provided outside the pump casing 2. Further, a static type variable voltage variable frequency power supply device composed of a semiconductor element is connected to a motor terminal box 12 of the recirculation pump 1 from a bus 13 in the office via an input circuit breaker 14 as a driving power supply.
15 are connected.

The variable voltage / variable frequency power supply device 15 comprises a semiconductor power conversion device and a speed control device, and the speed control device responds to a speed request from a flow control device for controlling a core flow rate. By controlling the ratio between the output voltage and the output frequency of the power converter to be constant,
Variable speed control of the recirculation pump 1 is performed.

Further, the speed control device has a dual redundant configuration of an operation system and a standby system, and when any abnormality occurs in the semiconductor power conversion device or the speed control device, the abnormality is detected. The system is quickly switched from the operation system to the standby system, and the standby system restarts the recirculation pump 1 before it stops due to its inertial motion.

As a result, since the recirculation pump 1 is operated without stopping, even when an abnormality occurs in the variable voltage / variable frequency power supply device 15, it is possible to continuously operate the reactor with no large fluctuation in the reactor power. Can be. The method of detecting the abnormality is based on the assumption that, for the semiconductor power converter, a set value corresponding to the rating of the constituent parts is used, and for the speed controller, the built-in control program operates normally. Originally, any abnormality was judged by detecting the abnormality of the constituting parts.

[0008]

However, the control program incorporated in the speed control device changes for some reason, and the control signal from the speed control device to the semiconductor power converter according to the speed of the recirculation pump 1 is changed. For example, even if a command signal for controlling the firing angle of the thyristor deviates from a command value corresponding to the speed, there is no method for detecting this.

In a semiconductor power conversion device of a voltage type inverter having a smoothing capacitor in a smoothing circuit portion, if an excessive charge is accumulated in the smoothing capacitor for some reason and an overvoltage state is caused by this, Upon detecting this overvoltage state, the speed control device is quickly switched to the standby system, and the recirculation pump 1 is quickly restarted by the speed control device of the standby system.

However, at the time of switching to the standby system, the speed control device and the semiconductor power converter of the standby system are operated under the precondition that they are in a normal state.
Had to be restarted. In this case, in the semiconductor power conversion device, when the smoothing capacitor is restarted from the overvoltage state, excessive charges accumulated in the smoothing capacitor are released at a stretch, so that the recirculation pump 1 receives an overcurrent as an inrush current. Occurs.

An overcurrent in the recirculation pump 1 is detected by an overcurrent protection device separately provided for protecting the variable voltage variable frequency power supply and the like, and the variable voltage variable frequency power supply is stopped. Accordingly, there is a possibility that the recirculation pump 1 temporarily stops after the inertial operation. In such a case, it is impossible to continue the operation without stopping the recirculation pump 1, and therefore, the circulation flow rate of the coolant in the core changes, which affects the fluctuation of the reactor power. Will be.

An object of the present invention is to provide a variable voltage variable frequency power supply for a reactor coolant recirculation pump, in which a control signal for a semiconductor power converter deviates from a limit value due to a control program abnormality of a speed control device. In the case or when excessive charge is accumulated in the smoothing capacitor provided in the semiconductor power conversion device, the system is promptly switched to the standby system and the recirculation pump is restarted to continue without stopping the recirculation pump. To provide a variable voltage and variable frequency power supply for a recirculation pump that is operated in a controlled manner.

[0013]

In order to achieve the above object, a variable voltage variable frequency power supply for a recirculation pump according to the present invention is provided with a semiconductor power converter for a voltage type inverter provided with a smoothing capacitor. A variable voltage variable frequency power supply for a recirculation pump comprising a speed control device, wherein the speed control device is provided with a plurality of redundant control systems, and the speed control is performed by detecting an abnormality in the variable voltage variable frequency power supply device. A protection circuit is provided for switching the control system of the device from the operation system to the standby system and performing the continuous operation of the recirculation pump.

[0014] The protection circuit provided in the speed control device, based on various information input from the variable voltage variable frequency power supply device,
The output for driving the recirculation pump detects, for example, an overvoltage caused by excessive charge accumulation in the smoothing capacitor of the semiconductor power conversion device and an abnormality of the overcurrent caused by the overvoltage.

Further, in the protection circuit, the recirculation pump is restarted by switching from the operation system of the control system made redundant by the speed control device to the standby system in response to the detected abnormal state. The overcurrent is prevented from affecting the operation of the recirculation pump, and the continuous operation is performed without stopping the recirculation pump.

According to a second aspect of the present invention, in the variable voltage variable frequency power supply for a recirculation pump according to the first aspect, when the control system is switched from the operation system to the standby system in the protection circuit, the semiconductor power conversion is performed. An abnormality is determined when the output current in the device exceeds the limit value, and the recirculation pump is restarted by suppressing the occurrence of overcurrent by limiting the output for a certain period of time.

The protection circuit determines that the output current of the semiconductor power converter has exceeded the limit value and determines that the output current is abnormal, restricts the output for a certain period of time, suppresses the occurrence of overvoltage, and switches to the standby system to recirculate. No excessive rush current flows when the pump is restarted.

According to a third aspect of the present invention, in the variable voltage variable frequency power supply device for a recirculation pump according to the first aspect, when the control system is switched from the operation system to the standby system in the protection circuit, the semiconductor power conversion is performed. Abnormality is determined when the output current in the device exceeds the limit value, the occurrence of overcurrent is suppressed by limiting the output for a certain period of time, and when the recirculation pump is restarted, the residual voltage phase of the recirculation pump and the standby system voltage It is characterized in that synchronization with the phase is confirmed.

In the protection circuit, when the output current of the semiconductor power conversion device exceeds the limit value, it is determined that there is an abnormality, and when the output is limited for a certain period of time to suppress the occurrence of overvoltage and switch to the standby system, The recirculation pump is restarted when the residual voltage phase of the recirculation pump matches or approaches the standby system voltage phase of the control system at the output of the converter. Thus, when the recirculation pump is restarted, no overvoltage or overcurrent occurs in the recirculation pump and the semiconductor power converter.

According to a fourth aspect of the present invention, in the variable voltage variable frequency power supply device for a recirculation pump according to the first aspect, when the control system is switched from the operation system to the standby system in the protection circuit, the semiconductor power conversion is performed. The output is limited by determining an abnormality when the voltage of the smoothing capacitor in the device exceeds the limit value, and the protection set value against overcurrent is changed for a fixed time to be equal to or less than the limit of the constituent elements of the semiconductor power conversion device. .

The protection circuit determines that there is an abnormality when the smoothing capacitor voltage of the semiconductor power conversion device exceeds the limit value, and protects against an overcurrent when switching the output from the operation system to the standby system by limiting the output for a certain period of time. Since the set value is changed below the limit of the component for a certain period of time, the overcurrent protection function is activated when the recirculation pump is restarted, thereby preventing the semiconductor power converter from stopping.

According to a fifth aspect of the present invention, in the variable voltage variable frequency power supply for a recirculation pump according to the first aspect, the protection circuit includes an overvoltage event caused by excessive charge accumulation in a smoothing capacitor of the semiconductor power conversion device. Is characterized in that the cause is detected before the occurrence, and the control system is switched from the operation system to the standby system.

The protection circuit detects that various kinds of information input from the variable voltage / variable frequency power supply deviate from the limit value or the set value of each corresponding part, and predicts and judges an abnormality to control the control system to the operation system. Switch from to the standby system. Thus, the switching to the standby system is immediately performed before the abnormality such as the overvoltage increases, so that the recirculation pump can be restarted without the abnormality increasing and without the influence.

According to a sixth aspect of the present invention, in the variable voltage variable frequency power supply for a recirculation pump according to the fifth aspect, in the protection circuit, the firing angle control signal from the speed controller for the semiconductor power converter is limited. It is characterized in that the control system is switched from the operation system to the standby system by making an abnormality prediction judgment when the value is exceeded.

For example, if the firing angle control signal from the speed control device for the semiconductor power converter exceeds a limit value due to an increase in output voltage due to excessive accumulation of charge in the smoothing capacitor, the protection circuit makes a prediction judgment of abnormality. Then, the control system is switched from the operation system to the standby system, and the recirculation pump is restarted. This quick switching to the standby system prevents the accumulation of excessive charges in the smoothing capacitor, so that an excessive rush current does not flow when the recirculation pump is restarted due to an overvoltage.

According to a seventh aspect of the present invention, in the variable voltage variable frequency power supply device for a recirculation pump according to the fifth aspect, the difference between the capacitor voltage of the smoothing capacitor and the voltage reference in the semiconductor power converter in the protection circuit. It is characterized in that the control system is switched from the operation system to the standby system by performing an abnormality prediction determination when the limit value is exceeded.

The protection circuit predicts and judges the abnormality of the capacitor voltage when the difference exceeds the deviation limit value from the difference between the capacitor voltage and the voltage reference, and changes the control system from the operation system to the standby system. Switch to restart the recirculation pump. As a result, excessive charges are accumulated in the smoothing capacitor, and this overvoltage prevents an excessive rush current when the recirculation pump is restarted.

[0028] In the variable voltage variable frequency power supply device for a recirculation pump according to the invention of claim 8, in the protection circuit, in the protection circuit, the input current in the semiconductor power converter corresponds to the speed of the recirculation pump. When the set value is exceeded, abnormality prediction is determined and the control system is switched from the operation system to the standby system.

The protection circuit provides a set value corresponding to each rotation speed of the recirculation pump. When the input current in the semiconductor power converter exceeds the set value corresponding to the rotation speed, it is determined that an abnormality has occurred. To switch the control system from the operation system to the standby system. Thus, the overcurrent protection of the components of the semiconductor power conversion device according to each rotation speed and the excessive rush current at the time of restarting the recirculation pump due to the overvoltage are prevented.

According to a ninth aspect of the present invention, in the variable voltage variable frequency power supply for a recirculation pump according to the fifth aspect, when the protection circuit detects a change in the control program by parity check of the control program, the abnormality prediction judgment is made. Then, the control system is switched from the operation system to the standby system.

The protection circuit detects a change or the like in the control program by a parity check of the control program, predicts and determines an abnormality from the parity error, and switches the control system from the operation system to the standby system. By this quick switching to the standby system, an abnormal event caused by a change in the control program is prevented, and the recirculation pump is smoothly restarted.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. Note that the same components as those of the above-described related art are denoted by the same reference numerals, and detailed description thereof will be omitted. The first embodiment relates to claim 1 or claim 2, and as shown in the block diagram of FIG. 1, a variable voltage variable for a recirculation pump, which is a drive power source for a recirculation pump 1 with a built-in nuclear reactor. The frequency power supply device 16 includes a semiconductor power conversion device 17 and a speed control device 18.

The semiconductor power converter 17 is a static type voltage type inverter, and includes a rectifier 19, a smoothing capacitor 20 of a smoothing circuit and an inverter 21, an input current detector 22, a capacitor voltage detector 23, and an output current. And a detector 24 and the like.
The speed control operation is performed by converting the power into AC power of an appropriate voltage and frequency and supplying the AC power to the recirculation pump 1.

The speed controller 18 controls the semiconductor power converter 17 to generate AC power of a voltage and a frequency in accordance with the speed request signal 25a from the flow controller 25.

The speed control device 18 includes an operation system 31 including a voltage / frequency reference circuit 26 and a voltage control circuit 27, an ignition angle control circuit 28, a frequency control circuit 29, and a protection circuit 30; And a plurality of systems including a standby system 32 having the same configuration as that described above (here, an example of two systems is shown). Therefore, for example, while the operation system 31 is operating, the switching signal 30 from the protection circuit 30 is provided.
a switching circuit for causing the standby system 32 to perform operation switching by a
It is configured so as to be redundant from the 33 (claim 1).

Further, the firing angle control circuit 28 of the speed control device 18 controls the firing angle of the thyristor element constituting the rectifier 19 of the semiconductor power conversion device 17 to change AC to DC and output voltage. Control. Further, the frequency control circuit 29 changes the direct current to the alternating current in the inverter 21 and controls the frequency to output the predetermined alternating current power to the recirculation pump 1.

In the semiconductor power converter 17, the input current signal 22a from the input current detector 22, the capacitor voltage signal 23a from the capacitor voltage detector 23, and the output current signal 24a , Inverter
An output signal 21 a and the like from 21 are input to the protection circuit 30 of the speed control device 18.

The protection circuit 30 for the operation system 31 and the standby system 32
As shown in the sequence diagram of FIG. 2, the recirculation pump 1 is restarted by switching from the operating system 31 to the standby system 32 or from the standby system 32 to the operating system 31 by the switching circuit 33 in the protection circuit 30. As a sequence for performing the determination, an abnormality determination element and an avoidance element are provided. This sequence corresponds to the output current signal 24 of the output current detector 24 in the semiconductor power converter 17.
The output current according to a is compared with a preset output current limit value 34, and if the output current exceeds the output current limit value 34, it is determined that an abnormality has occurred.

In this case, the switching to the standby system 32 is performed by the inverter 21 of the semiconductor power converter 17 and the frequency control circuit.
The output frequency control by 29 is stopped 35 for a fixed time. Therefore, in the smoothing capacitor 20 during the certain time, the excessively accumulated electric charge is discharged.

Thus, when the recirculation pump 1 is driven by the switched standby system 32 after the lapse of the predetermined time, it is possible to prevent an excessive rush current from flowing and an overcurrent protection device (not shown) from operating. In this case, the standby system 32 is configured to perform the restart 36 (claim 2).

Next, the operation of the above configuration will be described. In the variable voltage variable frequency power supply device 16 for the recirculation pump, the semiconductor power conversion device 17 inputs the AC power from the in-house bus 11 via the input circuit breaker 14, and converts the AC power into a DC of a predetermined voltage by the rectifier 19, This DC is a smoothing capacitor
Smoothed by 20. Further, the smoothed direct current is converted into an alternating current of a predetermined frequency and voltage by the inverter 21 and output.

This AC output is supplied to the recirculation pump 1 and drives the recirculation pump 1 at a predetermined rotational speed. In the nuclear reactor, an appropriate core flow rate is obtained and a predetermined output operation is performed. .

At this time, the operation system 31 of the speed control device 18
The firing angle of the semiconductor power converter 17 via the voltage control circuit 27 corresponding to the reference set value of the voltage / frequency reference circuit 26 in response to the speed request signal 25a given from the flow control device 25. Firing angle control signal 28 output from control circuit 28
The control of the firing angle of the thyristor element constituting the rectifier 19 is performed by a.

Further, also in the frequency control circuit 29, the semiconductor power converter 17 is controlled by controlling the inverter 21 in accordance with the reference set value of the voltage / frequency reference circuit 26.
Is controlled so that the ratio between the output voltage and the output frequency becomes constant, and the output power from the inverter 21 performs a predetermined variable speed control operation of the recirculation pump 1.

The control section of the speed control device 18 is initially operated in the operation system 31 because it is made redundant by the dual configuration of the operation system 31 and the standby system 32. When the protection circuit 30 or the like detects an abnormality in its own system, it outputs a switching signal 30a, switches the operating system 31 to the standby system 32 promptly by the switching circuit 33, and continues the operation of the recirculation pump 1. Let it.

Here, during the speed control by the operating system 31, for example, if an overvoltage occurs due to an excessive charge accumulated in the smoothing capacitor 20 of the semiconductor power conversion device 17 for some reason, this abnormal state The overvoltage is detected by the capacitor voltage detector 23 and output as a capacitor voltage signal 23a.

The capacitor voltage based on the capacitor voltage signal 23a is compared with a reference set value of the voltage / frequency reference circuit 26, and is input to the firing angle control circuit 28 via the voltage control circuit 27 and to the protection circuit 30. Is transmitted. The output current of the rectifier 19 increases due to the occurrence of the overvoltage. The output current is transmitted to the protection circuit 30 as an output current signal 24a of the output current detector 24.

When the protection circuit 30 outputs the switching signal 30a to the switching circuit 33, the speed control of the semiconductor power converter 17 by the speed controller 18 is switched from the operation system 31 to the standby system 32. The recirculation pump 1 is driven by the speed control by the standby system 32.

When the recirculation pump 1 is driven by the speed control by the standby system 32, the protection circuit 30 uses the output current signal 24a from the output current detector 24 as shown in the sequence of FIG. The output current is compared with a preset output current limit value 34.
Is exceeded, it is determined that an abnormality has occurred.

In this case, the output frequency control by the frequency control circuit 29 for the inverter 21 of the semiconductor power conversion device 17 is stopped for a certain period of time 35. Since the output from converter 21 is stopped, inertia operation is performed in recirculation pump 1.

While the recirculation pump 1 performs the inertial operation for a certain period of time, the excessively accumulated electric charge in the smoothing capacitor 20 is released. Thus, even if the recirculation pump 1 is restarted 36, an excessive rush current does not flow through the recirculation pump 1, so that the overcurrent protection device (not shown) does not operate.

As described above, when the operation system 31 and the standby system 32 of the speed control device 18 are mutually switched, the recirculation pump 1 is quickly restarted during the inertial operation without being temporarily stopped, and the output voltage is changed. And the operation is continued, so that the influence on the change in the circulation flow rate of the coolant in the reactor core is small, and the operation can be performed with high reliability without fluctuation in the reactor power.

Since the second embodiment is a modification of the first embodiment according to the third aspect, the same components as those in the first embodiment will not be described in terms of the configuration, operation, and effects. Is omitted, and different parts will be described. In the speed control device 18 of the recirculation pump variable voltage variable frequency power supply device 16, the protection circuit 30 of the operation system 31 and the standby system 32 includes the operation system 31 and the standby system 32 as shown in the sequence diagram of FIG. When the switching from the standby system 32 to the operating system 31 is performed, a sequence related to the restart of the recirculation pump 1 is provided.

In this sequence, the output signal 21 on the output side of the inverter 21 connected to the recirculation pump 1 in addition to the abnormality determination element and the avoidance element in the first embodiment.
The difference between the output voltage phase obtained from a and the controller phase 37 in the speed controller 18 is compared with a preset phase difference limit value 38, and the phase difference is a small value that does not exceed the phase difference limit value 39. It has a synchronization determination element on condition that there is a certain condition.

Thus, when the conditions for both the synchronization determination element and the abnormality determination element and the avoidance element are satisfied, the recirculation pump 1 is restarted 36 by speed control of the standby system 32. doing.

Next, the operation of the above configuration will be described. In the variable voltage variable frequency power supply 16 for the recirculation pump, for example, during the speed control operation by the operation system 31 in the speed control device 18, for some reason, excessive charge is accumulated in the smoothing capacitor 20 of the semiconductor power conversion device 17. It is assumed that the operation causes an overvoltage abnormality. At this time, the currently operating operation system 31 of the speed control device 18 is:
When the protection circuit 30 detects an abnormality, the switching circuit 33 switches to the standby system 32, and the standby system 32 controls the speed to drive the recirculation pump 1.

When the recirculation pump 1 is driven by the speed control of the standby system 32, the output current from the output current detector 24 is determined by the abnormality determining element in the protection circuit 30 as shown in the sequence of FIG. The output current by signal 24a;
The output current limit value 34 is compared with a preset output current limit value 34, and if the output current exceeds the output current limit value 34, it is determined that an abnormality has occurred.

In the switching to the standby system 32 in this case, the output frequency control by the frequency control circuit 29 for the inverter 21 is stopped for a fixed time 35, and the recirculation pump 1 is operated by inertia during this period. At the same time, excessive charges accumulated in the smoothing capacitor 20 are released to bring the state to a normal state. Therefore, when the recirculation pump 1 is restarted by the speed control of the standby system 32, an excessive rush current caused by the overvoltage does not flow, and the overcurrent protection device (not shown) does not operate.

Further, at the output side of the inverter 21 connected to the recirculation pump 1, the difference between the output voltage phase obtained from the output signal 21a and the controller phase 37 in the speed controller 18 is set in advance. When the phase difference is compared with the phase difference limit value 38 and the difference is smaller than the phase difference limit value 38, the condition for synchronization determination is set.

Therefore, in this sequence, together with the above-described conditions for abnormality determination and avoidance, the condition of synchronization of the control device phase in the speed control device 18 with the residual voltage phase of the recirculation pump 1 during inertia operation, or the condition of a state close to synchronization When both conditions are satisfied, the protection circuit 30 switches the switching circuit 33
Outputs the switching signal 30a to the standby system 32 in response to the
A restart 36 of the recirculation pump 1 by the speed control of 32 is performed.

Thus, when the speed control device 18 is switched from the operation system 31 to the standby system 32 or from the standby system 32 to the operation system 31, the recirculation pump 1 does not need to be temporarily stopped.
Because it restarts quickly during inertial driving and continues driving,
It has a small effect on the change in the circulation flow rate of the coolant in the reactor core, and can perform a highly reliable operation in which there is no fluctuation in the reactor power.

Further, since the synchronous adjustment is performed at the time of restarting the recirculation pump 1 as described above, especially when the recirculation pump 1 is restarted during the inertial operation, it is necessary to pay attention to a large capacity machine. The occurrence of overvoltage and overcurrent due to phase mismatch between the residual voltage phase held by the recirculation pump 1 and the control device phase 37 is prevented. Therefore, it is possible to prevent the components of the variable voltage / variable frequency power supply device 16 for the recirculation pump from being disturbed, and prevent the occurrence of a phenomenon that hinders the smooth start of the recirculation pump 1 due to the operation of the overcurrent protection device. Therefore, highly reliable switching and operation can be performed.

Since the third embodiment is a modification of the first embodiment according to the fourth aspect, the same components as those of the first embodiment will not be described with respect to the configuration, operation and effect. Is omitted, and different parts will be described. In the speed control device 18 of the recirculation pump variable voltage variable frequency power supply device 16, the protection circuit 30 of the operation system 31 and the standby system 32 includes, as shown in the sequence diagram of FIG. At the time of switching from the standby system 32 to the operation system 31 or from the standby system 32, a sequence related to the restart of the recirculation pump 1 is provided.

This sequence corresponds to the operation of the semiconductor power converter 17.
The voltage at the smoothing capacitor 20 is detected by the capacitor voltage detector 23, the capacitor voltage based on the capacitor voltage signal 23a is compared with a preset overvoltage set value 39, and the capacitor voltage exceeds the overvoltage set value 39. And an abnormality determining element for outputting a signal for a predetermined period of time.

Further, a protection set value of an overcurrent protection device or the like (not shown) is used to stop the output current set value 40 in a normal state, and to set the level of the overcurrent such as an inrush current to a level lower than the limit of the constituent elements of the circuit. In addition, a protection element for the output current set value 41 at the time of overvoltage is provided. Thereby, the frequency control circuit 29 in the speed control device 18 determines the semiconductor from the abnormality determination signal indicating that the abnormality determined by the abnormality determination element has continued for a certain period of time and the output current set value 41 at the time of overvoltage in the protection element. The output frequency control stop 35 for the inverter 21 of the power converter 17 is configured to be performed.

Next, the operation of the above configuration will be described. In the variable voltage variable frequency power supply device 16 for the recirculation pump, for example, during the speed control operation by the operation system 31, the semiconductor power conversion device 17
It is assumed that an excessive voltage accumulates in the smoothing capacitor 20 to cause an overvoltage. At this time, when the operating system 31 currently operating in the speed control device 18 detects an abnormality in the protection circuit 30, it switches to the standby system 32 by the switching circuit 33 and recirculates by the speed control by the standby system 32. The pump 1 is driven.

In this case, as in the sequence shown in FIG. 4, the capacitor voltage of the smoothing capacitor 20 is compared with a preset overvoltage set value 39 by the abnormality determining element of the protection circuit 30 to determine the capacitor voltage. Is determined to be abnormal when the voltage exceeds the overvoltage set value 39 for a predetermined time, and the normal output current set value 40 is stopped at the protection set value.

Further, the frequency control is performed by the output signal set value 41 at the time of the overvoltage, which is set in advance by setting the protection set value as the protection element to a level lower than the limit of the constituent elements of the circuit. The output frequency control stop 35 is performed from the circuit 29 to the inverter 21 of the semiconductor power conversion device 17. As a result, when switching to the standby system 32, the recirculation pump 1 is operated by inertia, and excessive charges accumulated in the smoothing capacitor 20 are released to return to a normal state.

Therefore, switching of the speed control device 18 from the operating system 31 to the standby system 32 or from the standby system 32 to the operating system 31 is performed as follows.
Since the recirculation pump 1 is restarted quickly during the inertia operation without being stopped, and the operation is continued, the influence on the change in the circulation flow rate of the coolant in the reactor core is small, and the reliability that the power of the reactor does not fluctuate does not occur. Highly reliable driving can be performed.

Further, in the protection element, the protection set value against the overcurrent due to the rush current generated in the circuit is changed from the normal output current set value 40 to the overvoltage at the level below the limit of the elements constituting the circuit. Switch to the output current setting value 41 for a fixed time. As a result, after passing the rush current due to the abnormal state, the recirculation pump 1 is restarted and the operation is continued, so that the reliability of the variable voltage variable frequency power supply 16 for the recirculation pump and the recirculation pump 1 is improved. I do.

The fourth embodiment is directed to the fifth and sixth aspects, wherein an abnormality such as an overvoltage event due to the accumulation of an excessive charge in the smoothing capacitor is detected before the occurrence of the abnormality to the standby system. Is switched. The description of the configuration, operation and effect of the same components as those in the first embodiment will be omitted, and different portions will be described.

In the speed control device 18 of the variable voltage variable frequency power supply device 16 for the recirculation pump, the protection circuit 30 of the operation system 31 and the standby system 32 transmits the standby signal from the operation system 31 as shown in the sequence diagram of FIG. A sequence for switching to the system 32 or from the standby system 32 to the operation system 31 is provided.

This sequence is performed by starting from the firing angle control circuit 28 in the speed control device 18 to the rectifier in the semiconductor power conversion device 17.
By comparing the firing angle control signal 28a output to step 19 with the preset firing angle limit value 42, the occurrence of abnormality is predicted when the firing angle control signal 28a deviates from the firing angle limit value 42. And the standby system
This is an abnormality determination element for switching to 32 (claim 6).

Further, for example, if an abnormality in the semiconductor power conversion device 17 causes an excessive charge to be accumulated in the smoothing capacitor 20, the firing angle will be increased before the output of the semiconductor power conversion device 17 clearly becomes overvoltage. A change occurs in the control signal 28a. Accordingly, by detecting that the change in the firing angle control signal 28a deviates from the preset firing angle limit value 42 as a factor of the overvoltage event, the occurrence of an overvoltage event or the like in the semiconductor power conversion device 17 is determined in advance. (Claim 5).

Next, the operation of the above configuration will be described. In the variable voltage variable frequency power supply device 16 for the recirculation pump, if the speed of the recirculation pump 1 changes for any reason during the speed control operation of the recirculation pump 1 by the operation system 31, for example, In response to the ignition angle control circuit 28, the rectifier 19 of the semiconductor power converter 17
The firing angle control signal 28a output to the controller changes.

For example, when an excessive charge is accumulated in the smoothing capacitor 20 of the semiconductor power conversion device 17, an abnormal state of an overvoltage occurs, and the speed of the recirculation pump 1 increases. At this time, in the operating system 31 currently operating in the speed control device 18, the firing angle control circuit 28
Since the firing angle control signal 28a output from the rectifier 19 to the rectifier 19 changes, the change in the firing angle control signal 28a is
In the abnormality determination element shown in the sequence of FIG.

Here, when the firing angle control signal 28a deviates from the firing angle limit value 42, a switching signal 30a is output to a switching circuit 33 (not shown) immediately after it is determined to be abnormal, and the switching circuit 33 Is switched to the standby system 32, and the recirculation pump 1 is driven by speed control by the standby system 32.

As a result, an excessive charge is accumulated in the smoothing capacitor 20 and, before an overvoltage condition is reached, the cause of this is detected and the operation system 31 is quickly switched to the standby system 32, so that the smoothing capacitor 20 is switched. Accumulation of excessive electric charge in 20 and the occurrence of abnormality in the recirculation pump 1 and the semiconductor power converter 17 are prevented beforehand.

Therefore, switching of the speed control device 18 from the operation system 31 to the standby system 32 or from the standby system 32 to the operation system 31 is performed before the overvoltage event from the inverter 21 to the recirculation pump 1 progresses. It is performed promptly in a state where the output voltage change is small. For this reason, since the operation is continued without stopping the recirculation pump 1 temporarily, the effect on the change in the circulation flow rate of the coolant in the reactor core is small, and the operation is highly reliable without fluctuation in the reactor power. Can be.

Since the fifth embodiment is a modification of the fourth embodiment according to the seventh aspect, the configuration of the same components as those of the first and fourth embodiments is the same as that of the first embodiment. Description of the operation, effects, and effects will be omitted, and different parts will be described. In the speed controller 18 of the variable voltage variable frequency power supply 16 for the recirculation pump, the protection circuit 30 of the operation system 31 and the standby system 32 is connected to the operation system 31 and the standby system 32 as shown in the sequence diagram of FIG. Or standby system 32
When switching from the operation system 31 to the operation system 31, a sequence related to the restart of the recirculation pump 1 is provided.

This sequence corresponds to the operation of the semiconductor power conversion device 17.
The voltage at the smoothing capacitor 20 is detected by the capacitor voltage detector 23, and the difference between the capacitor voltage based on the capacitor voltage signal 23a from the capacitor voltage detector 23 and the voltage reference from the voltage / frequency reference 26, and the preset deviation limit Compare the value 43, the difference between the capacitor voltage and the voltage reference, when the deviation exceeds the deviation limit value 43, predict the occurrence of abnormality,
This is an abnormality determination element for switching to the standby system 32.

Next, the operation of the above configuration will be described. In the variable voltage variable frequency power supply device 16 for the recirculation pump, for example, during the speed control operation of the recirculation pump 1 by the operation system 31 in the speed control device 18, an excessive voltage is applied to the smoothing capacitor 20 of the semiconductor power conversion device 17 for some reason. When the electric charge is accumulated, an overvoltage abnormality occurs. However, the rise in the voltage of the smoothing capacitor 20 is detected by the capacitor voltage detector 23, and is transmitted as the capacitor voltage signal 23a to the protection circuit 30 of the currently operating operation system 31 in the speed controller 18.

In the abnormality judging element of the protection circuit 30, the difference between the capacitor voltage and the voltage reference is compared with the deviation limit value 43 to determine the difference between the capacitor voltage and the voltage reference.
When the deviation limit value 43 is expanded to a certain value or more, the occurrence of abnormality is predicted and determined. As a result, the switching signal
30a is output to a switching circuit 33 (not shown), and the switching circuit
Switching to the standby system 32 is performed by 33, and this standby system 32
The recirculation pump 1 is driven by the speed control by.

Therefore, before an excessive charge is accumulated in the smoothing capacitor 20 and an overvoltage state is detected, the cause of the overvoltage is detected and the operation system 31 is quickly switched to the standby system 32. A recirculation pump 1 and a semiconductor power conversion device for preventing accumulation of excessive charges
The occurrence of an abnormality in 17 is prevented beforehand.

Thus, switching of the speed control device 18 from the operating system 31 to the standby system 32 or from the standby system 32 to the operating system 31 can be performed in a state where the output voltage change from the inverter 21 to the recirculation pump 1 is small. It is done promptly. From this,
Since the operation is continued without stopping the recirculation pump 1, it has little effect on the change in the circulation flow rate of the coolant in the reactor core, and the operation can be performed with high reliability without fluctuation in the reactor output.

Since the sixth embodiment is a modification of the fourth embodiment according to claim 8, the configuration of the same components as those of the first and fourth embodiments described above is the same as that of the first embodiment. Description of the operation, effects, and effects will be omitted, and different parts will be described. In the speed control device 18 of the variable voltage variable frequency power supply device 16 for the recirculation pump, the protection circuit 30 of the operation system 31 and the standby system 32 is connected to the protection system 30 from the operation system 31 to the standby system 32 as shown in the sequence diagram of FIG. Or standby system 32
When switching from the operation system 31 to the operation system 31, a sequence related to the restart of the recirculation pump 1 is provided.

This sequence is performed by the semiconductor power converter 17
The input overcurrent corresponding to the preset speed of the recirculation pump 1 when the input current based on the input current signal 22a detected by the input current detector 22 and the speed request signal 25a from the flow control device 25 (not shown) are input. Compare the set values 44a to 44n,
When the input current exceeds the input overcurrent set values 44a to 44n, it is an abnormality determination element that predicts occurrence of an abnormality and switches to the standby system 32.

Next, the operation of the above configuration will be described. When the control program in the operating system 31 changes for some reason during the operation of the recirculating pump 1 by the operating system 31 by the speed controller 18 of the variable voltage variable frequency power supply device 16 for the recirculating pump, for example, The command signal for controlling the firing angle of the thyristor in the semiconductor power conversion device 17 according to the speed deviates from the command value corresponding to the speed, and an overcurrent flows through the rectifier 19.

However, in this case, in the abnormality determining element of the protection circuit 30, the overcurrent protection level for the rectifier 19 corresponding to each speed of the recirculation pump 1 is set in advance as the input overcurrent set values 44a to 44n. I have. Therefore, the input current is compared with the input overcurrent set values 44a to 44n in the speed request signal 25a, and when the input current exceeds the input overcurrent set values 44a to 44n, it is determined that the input current is abnormal. A switching signal 30a is output to the switching circuit 33 to promptly switch to the standby system 32, and the recirculation pump 1 is driven by speed control by the standby system 32.

As a result, due to the abnormality of the control program in the operation system 31, an excessive charge is accumulated in the smoothing capacitor 20 and the cause is detected before the overvoltage state is reached.
By quickly switching from the standby system 31 to the standby system 32, the accumulation of excessive charges in the smoothing capacitor 20 and the occurrence of abnormalities in the recirculation pump 1 and the semiconductor power converter 17 are prevented.

Therefore, the operation can be quickly switched to the sound standby system 32 with little change in the output voltage from the inverter 21 to the recirculation pump 1, so that the operation is continued without stopping the recirculation pump 1 temporarily. Therefore, there is little influence on the change in the circulation flow rate of the coolant in the reactor core, and a highly reliable operation without fluctuation in the reactor power can be performed.

Since the seventh embodiment is a modification of the fourth embodiment according to the ninth aspect, the configuration of the same components as those of the first and fourth embodiments is the same as that of the first and fourth embodiments. Description of the operation, effects, and effects will be omitted, and different parts will be described. In the speed control device 18 of the variable voltage variable frequency power supply device 16 for the recirculation pump, the protection circuit 30 of the operation system 31 and the standby system 32 is connected to the operation system 31 and the standby system 32 as shown in the sequence diagram of FIG. Or standby system 32
When switching from the operation system 31 to the operation system 31, a sequence related to the restart of the recirculation pump 1 is provided.

This sequence is determined to be abnormal due to a parity error 45 output when there is a change in the various control programs, based on the results of self-diagnosis (not shown) performed on various control programs in the speed control device 18. This is an abnormality determination element that performs a determination and outputs a switching signal 30a to the switching circuit 33 to perform switching.

Next, the operation of the above configuration will be described. The speed control device 18 of the variable voltage variable frequency power supply 16 for the recirculation pump, for example, when the control program or the like changes for some reason during the operation of the recirculation pump 1 by the operation system 31, the content or degree If an abnormality is diagnosed by the self-diagnosis according to the above, a parity error 45 is output.

When the parity error 45 is input, the abnormality determining element in the protection circuit 30 predicts the occurrence of an abnormality, outputs a switching signal 30a to the switching circuit 33, and immediately switches to the standby system 32. The recirculation pump 1 is driven by the speed control by 32.

Thus, for example, an excessive charge is accumulated in the smoothing capacitor 20 due to an abnormality in the control program or the like in the operation system 31 and a factor is detected before the overvoltage state occurs. By performing the switching quickly, excessive charge is accumulated in the smoothing capacitor 20, and
The occurrence of abnormalities in the recirculation pump 1 and the semiconductor power conversion device 17 is prevented beforehand.

[0097] Therefore, the state can be quickly switched to the sound standby system 32 with little change in the output voltage from the inverter 21 to the recirculation pump 1, and the operation can be continued without stopping the recirculation pump 1 temporarily. In addition, there is little influence on the change in the circulation flow rate of the coolant in the reactor core, and a highly reliable operation without fluctuation in the reactor power can be performed.

[0098]

As described above, according to the present invention, in a smoothing circuit or the like of a variable voltage variable frequency power supply, even if an overvoltage is generated without detecting an overvoltage, this abnormality is detected in advance or early. This allows the speed control device to be quickly and accurately switched to the standby system,
Avoids overcurrent at restart of the recirculation pump due to overvoltage, and ensures smooth operation of the variable frequency power supply and the recirculation pump, and reliability of reactor operation in which power is controlled by this recirculation pump. The performance is improved.

[Brief description of the drawings]

FIG. 1 is a block circuit configuration diagram of a variable frequency power supply device for a recirculation pump according to a first embodiment of the present invention.

FIG. 2 is a sequence diagram related to restart of the first embodiment according to the present invention.

FIG. 3 is a sequence diagram related to restart of the second embodiment according to the present invention.

FIG. 4 is a sequence diagram related to a restart of the third embodiment according to the present invention.

FIG. 5 is a sequence diagram related to the restart of the fourth embodiment according to the present invention.

FIG. 6 is a sequence diagram related to a restart according to the fifth embodiment of the present invention.

FIG. 7 is a sequence diagram related to the restart of the sixth embodiment according to the present invention.

FIG. 8 is a sequence diagram related to the restart of the seventh embodiment according to the present invention.

FIG. 9 is a longitudinal sectional view of a reactor coolant recirculation pump.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recirculation pump with a built-in reactor, 2 ... Pump casing, 3 ... Reactor pressure vessel, 4 ... Motor rotor, 5 ... Pump shaft, 6 ... Pump impeller, 7 ... Pump diffuser,
8 Upper journal bearing, 9 Lower journal bearing, 10
… Motor stator, 11… stator winding, 12… motor terminal box,
13 ... internal bus, 14 ... input circuit breaker, 15, 16 ... variable frequency power supply for recirculation pump, 17 ... semiconductor power converter, 18 ...
Speed control device, 19… Rectifier, 20… Smoothing capacitor, 21…
Inverter, 21a ... output signal, 22 ... input current detector, 22a
... Input current signal, 23 ... Capacitor voltage detector, 23a ... Capacitor voltage signal, 24 ... Output current detector, 24a ... Output current signal, 25 ... Flow control device, 25a ... Speed request signal, 26 ...
Voltage / frequency reference circuit, 27: voltage control circuit, 28: firing angle control circuit, 28a: firing angle control signal, 29: frequency control circuit, 30: protection circuit, 31: operation system, 32: standby system, 33 ... Switching circuit, 34 ... Output current limit value, 35 ... Output frequency control stop,
36 ... Restart, 37 ... Control device phase, 38 ... Phase difference limit value, 39
… Overvoltage set value, 40… Output overcurrent set value (normal), 41
… Output overcurrent set value (at overvoltage), 42… Fire angle limit value,
43: Deviation limit value, 44a to 44n: Input overcurrent set value, 45:
Parity error.

Claims (9)

[Claims] 1. A variable voltage variable frequency power supply for a recirculation pump comprising a semiconductor power conversion device of a voltage type inverter provided with a smoothing capacitor and a speed control device, wherein the speed control device is provided with a plurality of redundant control systems. Along with
A protection circuit is provided which detects an abnormality in the variable voltage variable frequency power supply device, switches a control system of the speed control device from an operation system to a standby system, and performs continuous operation of the recirculation pump. Variable voltage variable frequency power supply for circulation pump. In the protection circuit, when switching a control system from an operation system to a standby system, an abnormality is determined when an output current in the semiconductor power conversion device exceeds a limit value, and a limit of output for a predetermined time is performed. 2. The variable voltage variable frequency power supply device for a recirculation pump according to claim 1, wherein the recirculation pump is restarted while suppressing the occurrence of overcurrent. In the protection circuit, when switching a control system from an operation system to a standby system, an abnormality is determined when an output current in the semiconductor power conversion device exceeds a limit value,
2. The method according to claim 1, wherein the generation of overcurrent is suppressed by limiting the output for a predetermined time, and at the time of restarting the recirculation pump, synchronization between the residual voltage phase of the recirculation pump and the standby system voltage phase is confirmed. Variable voltage variable frequency power supply for recirculation pump. 4. In the protection circuit, when switching a control system from an operation system to a standby system, an abnormality is determined when the smoothing capacitor voltage in the semiconductor power conversion device exceeds a limit value, and output is limited. 2. The variable voltage variable frequency power supply for a recirculation pump according to claim 1, wherein a protection set value for an overcurrent is changed for a predetermined time to be equal to or less than a limit of the constituent elements of the semiconductor power conversion device. 5. The protection circuit detects a cause of an overvoltage event caused by excessive charge accumulation in a smoothing capacitor of the semiconductor power conversion device before occurrence, and switches a control system from an operation system to a standby system. The variable voltage / variable frequency power supply for a recirculation pump according to claim 1, wherein the power supply is performed. 6. In the protection circuit, when a firing angle control signal from a speed control device for the semiconductor power conversion device exceeds a limit value, abnormality prediction is determined and a control system is switched from an operation system to a standby system. 6. The variable voltage / variable frequency power supply for a recirculation pump according to claim 5, wherein: 7. In the protection circuit, when a difference between a capacitor voltage of a smoothing capacitor in the semiconductor power converter and a voltage reference exceeds a limit value, an abnormality prediction is determined and a control system is switched from an operation system to a standby system. 6. The variable voltage variable frequency power supply for a recirculation pump according to claim 5, wherein the switching is performed. 8. In the protection circuit, when an input current in the semiconductor power converter exceeds a set value corresponding to a speed of a recirculation pump, abnormality prediction is determined and a control system is changed from an operation system to a standby system. 6. The variable voltage variable frequency power supply for a recirculation pump according to claim 5, wherein the switching is performed. 9. The protection circuit according to claim 1, wherein when a change in the control program is detected by a parity check of the control program, an abnormality prediction judgment is made and the control system is switched from the operation system to the standby system. 6. The variable voltage variable frequency power supply for a recirculation pump according to claim 5.