JP3141226B2 - Core flow control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core flow rate control system for controlling a flow rate by a pump having a small moment of inertia connected to an MG set with a fluid coupling having an AC generator having a large moment of inertia in a power plant.

[0002]

2. Description of the Related Art Conventionally, among the improved boiling water nuclear power plants, in order to improve the pump speed controllability and minimize the influence of external power system disturbances, the coolant inside the core pressure vessel is re-used. A variable frequency power supply (hereinafter referred to as a fluid coupling) comprising an AC motor, a fluid coupling and an AC generator mechanically connected as a power supply device and a control device for the internal pump is provided with 10 internal pumps for circulation. It is optimal to apply two MG sets. In this case, the AC motor of the MG set with a fluid coupling is supplied with electric power from an external power supply, rotates at a constant speed after starting, and transmits torque to an AC generator mechanically connected via the fluid coupling. Five internal pumps are connected to one AC generator, and power is supplied to each pump from the AC generator. Here, the amount of oil in the fluid coupling is adjustable, and by adjusting the amount of oil, the torque transmitted from the AC motor to the AC generator is changed to change the speed of the AC generator and each internal connected thereto. The pump speed is controlled to control the core flow rate. In such a configuration, in order to minimize the torque transmitted from the AC motor to the AC generator, pull out the rake pipe as much as possible, start the AC motor in the lowest position, and change the speed of the AC generator. Is turned on at a sufficiently low 10% speed to start the internal pump connected to the AC generator. However, the rake pipe can adjust the amount of oil in the fluid coupling to the position of the rake pipe after the fluid coupling has started rotating sufficiently. Since it does not function, the amount of oil is relatively large with respect to the rake pipe position. Therefore, the alternator has
A torque larger than the rake pipe position is transmitted,
The alternator speed will be started at a high state. On the other hand, when controlling the speed of the internal pump using the MG set with fluid coupling, an automatic voltage regulator (AVR)
Is used to form a speed control system. Conventionally, control is performed such that the ratio (V / f) between the AC generator voltage and the AC generator frequency (used in a sense equivalent to the speed) is always constant. . Therefore, when the AC generator speed is started in a high state, the AC generator voltage changes to a high state in proportion to the change in the AC generator speed, and the internal pump controlled by the AC generator voltage is turned on. The speed will rise sharply to the alternator speed almost simultaneously with startup. As a result, the core flow rate increases rapidly, causing an overshoot of the neutron flux.In consideration of instrument errors and noise, the probability of a neutron flux high warning is extremely high, and the margin for the neutron flux high scram is sufficient. However, there is a problem that good internal pump starting characteristics cannot be secured.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to suppress neutron flux overshoot at the time of starting the internal pump, to secure a sufficient margin for a high neutron flux scram, and to improve the internal pump starting characteristics. To provide a core flow control system having the same.

[0004]

In order to achieve the above object , a variable motor having a drive motor, a fluid coupling, and an alternator is provided.
A frequency power supply unit and an AC generator installed in the reactor
The internal pump driven by the
Core flow control system consisting of pressure / frequency control
Control system , wherein the control device is a starter for the variable frequency power supply.
Voltage / frequency conversion constant used during operation and for steady operation
Voltage / frequency conversion constant. Where the variable frequency
When starting up the power supply, the voltage / period used during normal operation
Voltage / frequency conversion constant used at startup from wave number conversion constant
After a predetermined period of time,
Is switched again to the voltage / frequency conversion constant used for. here
When the variable frequency power supply is started,
The voltage / frequency used at startup from the voltage / frequency conversion constant
Switch to wave number conversion constant, internal pump operates at lowest speed
When the speed is increased to the degree, the voltage / frequency
Switch back to the number conversion constant. Here, the control device
Use at startup as a function of time as a pressure / frequency conversion constant
From the voltage / frequency conversion constant
/ Variable constant that changes to frequency conversion constant
Between the start of the power supply unit and the steady operation.
Switch to variable constant. Here, the control device operates during normal operation.
To slowly change the voltage / frequency conversion constant used for
From the start of the variable frequency power supply
The voltage / frequency conversion constant is used up to the time of steady operation.
Switch to the variable constant output by the change rate limiting means. Ma
In addition, when the variable frequency power supply starts,
Reduce the torque transmitted to the internal pump in the circuit
A resistor is provided. Also, AC excitation is applied to the variable frequency power supply.
A porcelain machine is provided, and when the variable frequency power supply
Torque transmitted to the internal pump in the field circuit of the machine
Is provided. Also, the control device has a variable
When starting wavenumber power supply frequency than that in the steady operation
Reduce the voltage change with respect to the change .

[0005]

According to the present invention, the speed at the start of the internal pump is changed by changing the voltage / frequency (V / f) conversion constant in the automatic voltage regulator (AVR) between the start of the internal pump and the normal operation. Since it is possible to suppress the rise and reduce the fluctuation width of the core flow rate, it is possible to suppress the neutron flux rise overshoot and to operate the reactor stably.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a core flow rate control system showing one embodiment of the present invention. In FIG. 1, ten internal pumps 16a to 16
16j are provided on the same circumference (only one MG set with fluid coupling and five internal pumps are shown in FIG. 1). The AC motor 3 has a primary side (stator) connected to the power supply 1 via a circuit breaker 2 and a secondary side (rotor) mechanically connected to an AC generator 5 via a fluid coupling 4 which is a variable speed device. Linked to The fluid coupling 4 can adjust the amount of oil in the fluid coupling. By adjusting the amount of oil, the torque transmitted from the AC motor 3 to the AC generator 5 is changed to control the speed of the AC generator. I do. In the AC generator 5, the field winding 9 is connected to the AC exciter 6 via the field circuit breaker 8 and the rectifying diode 7, and the circuit breakers 13 and 14a to 14c.
It is connected to motors 15a to 15e mechanically directly connected to the internal pumps 16a to 16e via 14e, and supplies electric power to the motors 15a to 15e to control the internal pump speed. Here, the variable frequency power supply (MG set with a fluid coupling) includes an AC motor 3, a fluid coupling 4, and an AC generator 5. The AC exciter 6 is directly connected to the AC motor 3 and its field winding 23 is connected to the exciting transformer 2.
2. Connected to the alternator 5 via the thyristor 25,
Part of the power is supplied from the AC generator 5. The automatic voltage regulator (AVR) 100 is connected to the AC generator 5 via the instrument transformer 21 and to the detector 10 for detecting the rotation speed of the AC generator 5 by a pulse. A voltage signal 26 obtained by measuring the output voltage via the instrument transformer 21
And a frequency signal 12 obtained by detecting the number of revolutions of the alternator 5 via the detector 10, and connected to the gate of the thyristor 25 via the diode 24, corresponding to obtaining a predetermined generator voltage. The pulse signal 27 of the firing angle is output to the gate of the thyristor 25.

FIG. 2 shows details of the automatic voltage regulator 100 in the embodiment of FIG. The automatic voltage regulator 100
/ F converter 200, voltage converter 101, adder 102,
It comprises a voltage converter 103 and a pulse signal calculator 104. Frequency signal 1 detected as rotation speed of AC generator 5
2 is converted to a voltage by the V / f converter 200, while
The voltage signal 26 detected as the output voltage of the AC generator 5 is converted by the voltage converter 101, the two voltages converted by the adder 102 are added, and the added signal is input to the pulse signal calculator 104. Pulse signal calculator 104
From the signal from the adder 102 and the signal obtained by converting the voltage signal 26 by the voltage converter 103, the field winding 23 of the AC exciter 6 is used to set the generated voltage of the AC generator 5 to an appropriate value. Is calculated, and a pulse signal 27 for firing the thyristor 25 is output.

FIG. 3 shows a V / f converter 200 shown in FIG.
2 shows a detailed embodiment of the present invention. In FIG. 3, the frequency signal 1
2 is multiplied by the V / f conversion constant (K) 201 and output to the adder 102. As for the value of the V / f conversion constant (K) 201, the constants (K ₁ ) 202, the constant (K ₀ ) 203, and the variable constant (Kv) 204 are appropriately set by turning on / off the switches 213 to 215. You. Here, the constant (K
₁ ) 202 is a constant at which the ratio of the rated frequency to the rated voltage is 1: 1 during normal operation, a constant (K ₀ ) 203 is a constant for reducing the voltage change with respect to the frequency change at the time of startup, and a variable constant (Kv). Reference numeral 204 denotes a variable constant that changes with time T (seconds) from a constant at start-up (K ₀ ) to a constant at normal time (K ₁ ). The switches 213 to 215 switch the OR circuit 2 according to the pump start command signal 28 and the pump speed-up completion signal 29.
05, 211, an AND circuit 209, a timer 210, and a wipe-out circuit 206, 207, 212 through a logic circuit.

Hereinafter, a method of starting the internal pumps 16a to 16e when this embodiment (FIGS. 1 to 3) is applied will be described. First, when starting the MG set with a fluid coupling, the circuit breaker 2 of the AC motor 3 is closed by the start request signal 28. At the same time, the start request signal 28 is sent to the automatic voltage regulator 1
00 is input to the V / f converter 200 in FIG. When the circuit breaker 2 is closed, the AC motor 3 starts, and reaches the rated speed over a certain period of time. The fluid coupling 4 transmits the rotational torque of the AC motor 3 to the AC generator 5, and the AC generator 5 is also started,
The motor is driven to follow the rotation speed of the AC motor 3. When the rotation speed of the AC generator 5 has reached a predetermined value (relatively low rotation speed), the field circuit breaker 8 is closed, and the AC exciting machine 6 excites the field winding 9 of the AC generator 5. Supply current. The AC generator 5 generates electric power, supplies the electric power to the motors 15a to 15e, and starts the internal pumps 16a to 16e. At the same time, the voltage generated by the AC generator 5 is input to the automatic voltage regulator (AVR) 100 as a voltage signal 26, and the rotation speed of the AC generator 5 is input as a frequency signal 12. Since the activation request signal 28 is input to the V / f converter 200 in the automatic voltage regulator (AVR) 100, the OR
The condition of the circuit 205 is satisfied and the switch 214 is turned on, while the switch 215 is turned off by the wipe-out circuit 212 (B). Here, V / f conversion constant (K) 2
The value of 01 is a constant (K ₁ ) that reduces a voltage change with respect to a frequency change at the time of starting from a constant (K ₁ ) 202 during normal operation.
₀ ) 203 is set. This means that the voltage change width with respect to the frequency change width at startup is smaller by a certain value than the change width at normal times. The frequency signal 12 is multiplied by the constant (K ₀ ) 203, converted into a voltage, and output to the adder 102. Adder 102
Then, the voltage converted by the V / f converter 200 and the voltage obtained by converting the voltage signal 26 by the voltage converter 101 are added. The pulse signal calculator 104 outputs the pulse signal 27 having a smaller call angle than the normal call angle based on the addition result and the voltage converted by the voltage converter 103. Therefore, the exciting current flowing from the thyristor 25 to the field winding 23 of the AC exciter 6 is suppressed,
The power generation voltage of the AC generator 5 is suppressed with respect to the rotation speed of the AC generator 5, and the rotation speeds of the internal pumps 16a to 16e are reduced. As described above, when the MG set with a fluid coupling is started, by using the starting constant (K ₀ ) 203, the generated voltage of the AC generator 5 can be suppressed lower than the rotation speed of the AC generator 5. Therefore, the rotation speeds of the internal pumps 16a to 16e become slow, and the internal pump speed rapidly increases to the AC generator speed almost simultaneously with the start of the AC motor, as in the conventional MG set with a fluid coupling. Problem can be solved.

Next, the internal pumps 16a to 16
When e slowly rotates at the time of startup and speeds up to the minimum pump speed (20%), a pump speed-up completion signal 29 is issued. When the pump speed-up completion signal 29 is input to the V / f converter 200 in the automatic voltage regulator 100, an AND condition 209 with turning on (A) of the switch 214 is satisfied.
As a result, the switch 21 is
At the same time as switch 4 is turned off, switch 213 is turned on and V
The / f conversion constant (K) 201 includes a starting constant (K ₀ )
Instead of 203, a variable that gradually changes at a time T (second) from a constant at startup (K ₀ ) to a constant at normal time (K ₁ ) based on the point in time when the variable constant (Kv) 204 starts to change. A constant (Kv) 204 is set. Further, when T (second) elapses after the generation of the pump speed-up completion signal 29 and the value of the variable constant (Kv) 204 becomes the normal constant (K ₁ ), a signal is output from the timer 210 and the OR circuit is output. 211 is established. As a result, the switch 213 is turned off by the wipe-out circuit 207, and the switch 21 is turned off.
5 is turned on, and the V / f conversion constant (K) 201 is replaced with a constant (K ₁ ) 2 at normal time instead of the variable constant (Kv) 204.
02 is set. Thus, the internal pump 1
After the pump speed reaches the minimum pump speed after the start of 6a to 16e, that is, after the completion of the pump speed-up, the variable constant (Kv) 20
4, the ratio of voltage to frequency (V
/ F) can be gently changed from the value at the time of start-up to the value at the time of normal operation. As a result, there is no stepwise change in the frequency of the AC generator, and the control at the time of normal operation can be started.

FIG. 4 shows the characteristics at the time of starting the internal pump in the case where the present embodiment is applied and in the case where the conventional method is used. The solid line in the figure is the case according to the present invention, and the dotted line is the case according to the conventional method. In the case of the conventional method, immediately after the field circuit breaker 8 is turned on, as shown in FIG.
Immediately rises to the speed of the alternator 5. As a result, as shown in Fig. (B), the core flow rapidly increased, and as shown in Fig. (C), the neutron flux overshoot was large, the neutron speed maximum reached about 100%, and the scram set value was reached. The margin for is small. On the other hand, if the present embodiment is applied, the V / f converter 200 is turned on at the same time when the circuit breaker 2 is turned on (time 0 in FIG. 4).
The value of the V / f conversion constant (K) 201 in the middle is a constant (K ₀ ) 2 for reducing a change in voltage with respect to a change in frequency for starting.
Since you are 03, as compared with the conventional case where the normal time constant at any time during startup as system (K ₁₎ Using the 202, gradual rise of as in (a) Figure, the internal pump frequency (i.e., speed) become. As a result, as shown in FIG. 2B, the increase in the core flow rate becomes gentle,
As shown in the figure, the maximum value of the neutron flux also has a sufficient margin with respect to the scrum set value.

FIG. 5 shows the V / f converter 200 shown in FIG.
Is shown in another embodiment. 5 is different from FIG. 3 in that the switches 213 to 215 are operated only by the pump start command signal and the OR circuit 205, the timer 209,
210, which is turned on / off via a logic circuit consisting of wipe-out circuits 206, 207, 208. Others are the same as those in FIG. 3 and the description is omitted. When the start command signal 28 is input to the V / f converter 200, the switch 215 is turned off by the wipe-out circuit 208 (B), and at the same time, the OR circuit 205 is established and the switch 214 is turned on. As a result, the V / f conversion constant (K) 201 includes:
Instead of the constant (K ₁ ) 202 during normal operation, a constant (K ₀ ) 203 at the time of startup is set. Also, a start command signal 2
8 is input to a timer 209 in which a time T ₁ (second) sufficient for the internal pump to complete the speed-up to the minimum pump speed is set. The timer 209 outputs a signal after a lapse of T ₁ (second) after the input of the start command signal 28,
When the switch 213 is turned on, the switch 214 is turned off by the wipe-out circuit 206. As a result, V
The / f conversion constant (K) 201 includes a starting constant (K ₀ )
A variable constant (Kv) 204 is set instead of 203.
Further, the output signal from the timer 209 is a timer 210 having the variable time (Kv) 204 and the time T (second) that is the same as the time T (second) of the function set in the variable constant (Kv) 204 as the set value. Is input to Therefore, T (seconds) after the signal is input to the timer 210, the timer 2
10, the switch 215 is turned on, and at the same time, the switch 213 is turned on by the wipe-out circuit 207.
Cut off. As a result, the setting of the V / f conversion constant (K) 201 switches from the variable constant (Kv) 204 to the constant (K ₁ ) 202 during normal operation. This embodiment has a simpler configuration than the embodiment of FIG. 3, and has the same effect as that of the embodiment of FIG. 3 shown in FIG.

FIG. 6 shows the V / f converter 200 shown in FIG.
Is shown in another embodiment. 6, a V / f converter 200 inputs a deviation from a memory 216 for constantly recording the value of a V / f conversion constant (K) 201, an adder 225, and an adder 225, and turns on switches 221 and 222. Monitor 217 to be turned off, and input a constant (K ₁ ) 202 at a normal time,
Rate-of-change limiter 21 that slowly changes the value of V / f conversion constant (K) 201 to the value of constant (K ₁ ) at normal time
8 The frequency signal 12 is a V / f conversion constant (K)
The result is multiplied by 201 and output to the adder 102. V / f
The value of the conversion constant (K) 201 is determined by the switches 223 to 224.
By turning on / off, the constant (K ₀ ) 203 and the constant (K ₁ ) 202 are appropriately set. Switch 223 ~
224 is turned on / off via an OR circuit 219 in response to a pump start command signal 28 and a pump speed-up completion signal 29.

The present embodiment (FIGS. 1 to 2 and FIG. 6)
When internal pumps are applied, internal pumps 16a to 16e
The method of starting is described. First, when starting the MG set with a fluid coupling, the circuit breaker 2 of the AC motor 3 is closed by the start request signal 28. At the same time, the activation request signal 28 is input to the V / f converter 200 in the automatic voltage regulator 100. When the circuit breaker 2 is closed, the AC motor 3 starts, and reaches the rated speed over a certain period of time. The fluid coupling 4 transmits the rotational torque of the AC motor 3 to the AC generator 5,
Is also started, and driven by following the rotation speed of the AC motor 3. When the rotation speed of the AC generator 5 has reached a predetermined value (relatively low rotation speed), the field circuit breaker 8 is closed, and the AC exciting machine 6 excites the field winding 9 of the AC generator 5. Supply current. The AC generator 5 generates electric power, and this electric power is
5a to 15e to supply internal pumps 16a to 1
6e is started. At the same time, automatic voltage regulator (AVR) 1
At 00, the generated voltage of the AC generator 5 is input as a voltage signal 26, and the rotation speed of the AC generator 5 is input as a frequency signal 12. V in automatic voltage regulator (AVR) 100
Since the start request signal 28 is input to the / f converter 200, the condition of the OR circuit 219 is satisfied, and the switch 223
Is turned on, and at the same time, the switch 224 is turned off. Here, as the value of the V / f conversion constant (K) 201, a constant (K ₀ ) 203 for reducing a voltage change with respect to a frequency change at the time of starting is set from a constant (K ₁ ) 202 during normal operation. Will be. This means that the voltage change width with respect to the frequency change width at startup is smaller by a certain value than the change width at normal times. The frequency signal 12 is multiplied by the constant (K ₀ ) 203, converted into a voltage, and output to the adder 102. The adder 102 adds the voltage converted by the V / f converter 200 and the voltage obtained by converting the voltage signal 26 by the voltage converter 101. The pulse signal calculator 104 calculates the sum of the addition result and the voltage
Based on the voltage converted by 3, the pulse signal 27 having a smaller call angle than the normal call angle is output. Therefore, the thyristor 25 switches the field winding 2 of the AC exciter 6
3 is suppressed, the generated voltage of the AC generator 5 is suppressed with respect to the rotation speed of the AC generator 5, and the rotation speeds of the internal pumps 16a to 16e are reduced.

Next, the internal pumps 16a to 16
When e slowly rotates at the time of startup and speeds up to the minimum pump speed (20%), a pump speed-up completion signal 29 is issued. When the pump speed-up completion signal 29 is input to the V / f converter 200 in the automatic voltage regulator 100, the switch 223 is turned off at the same time as the switch 223 is turned off by the wipe-out circuit 220, and the V / f conversion constant is set. In the (K) 201, a constant (K ₁ ) 202 at the normal time is set instead of the constant (K ₀ ) 203 at the time of starting. On the other hand, the value of the V / f conversion constant (K) 201 is always recorded in the memory 216 provided on the exit side of the V / f conversion constant (K) 201, and the recorded value and the normal time constant (K ₁ )
The value of 202 is calculated by the adder 225, and the deviation is input to the monitor 217. The monitor 217 outputs a signal when the deviation of the input signal becomes zero. Immediately after the pump speed-up completion signal 29 is established and the switch 224 is turned on, V
The output value of the / f conversion constant (K) 201 is a constant (K ₀ ) at the time of startup, and has a large deviation from the constant (K ₁ ) at the time of normal operation. Therefore, the signal (A) is not output from the monitor 217, the switch 221 is off, and the switch 222 is on. Therefore, if the constant (K ₁ ) in the normal state is input to the V / f conversion constant (K) 201 after the switch 224 is turned on, the constant (K ₁ ) 202 is
8, the V / f conversion constant (K) 20
The value of 1 gradually changes to the value of the normal time constant (K ₁ ). Thus, the V / f conversion constant (K) 20
When the value of ₁ changes to the normal time constant (K ₁ ), the input signal to the monitor 217 becomes zero, so that the monitor 217 outputs the signal (A). As a result, the switch 222
Is turned off, and the switch 221 is turned on. in this way,
After the minimum pump speed is reached after the internal pumps 16a to 16e are started, that is, after the pump speed-up is completed, the constant at start (K ₀ ) is changed from the constant at start (K ₀ ) to the constant at normal time (K By switching to ₁ ), the ratio of the voltage to the frequency (V / f) can be gradually changed from the value at the time of starting to the value at the time of normal operation. And normal control can be started. Also in the case of the present embodiment, the effect shown in FIG. 4 can be obtained as in the embodiment of FIG.

FIG. 7 shows another embodiment of the present invention. The embodiment described above uses the V / f in the automatic voltage regulator 100.
The example in which the internal pump starting characteristics are improved by performing control for appropriately changing the value of the V / f conversion constant (K) 201 in the converter 200 has been described. In this embodiment, an example will be described in which an effect equivalent to the effect of changing the conversion constant is obtained by an electric circuit. 7 differs from the embodiment of FIG. 1 in that an AC generator field circuit composed of a field winding 9, a field circuit breaker 8, and a rectifying diode 7 is connected to an internal pump only at startup. The point is that a resistor 34 and changeover switches 32 and 33 which are sufficient to reduce the transmission torque are provided. Other configurations are the same as those in the embodiment of FIG. 1, and the description is omitted. When turning on the field breaker 8 when the internal pump is started, the start command signal 28 causes the switch 3 via the OR circuit 35 to be turned on.
2 is closed and the switch 33 is opened. As a result, at the time of startup, the current flowing through the field circuit of the AC generator is reduced by the resistance 34, so that the power output from the AC generator 5 to the internal pump motor 16 is reduced, and Speed can be kept low.
Further, the start command signal 28 is input to a timer 30 having a time T (second) sufficient for the internal pump 16 to complete the acceleration from the start to the minimum pump speed. Since the timer 30 outputs a signal to the wipe-out circuit 31 after a time T (second), the switch 32 is opened and the switch 33 is closed by this signal. As a result, the resistor 34 is excluded from the AC generator field circuit, and the current of the field circuit becomes a value during normal operation. In the present embodiment, the effect shown in FIG. 4 is obtained as in the embodiment of FIG. Further, even when the resistor 34, the switch 32, and the switch 33 are provided on a circuit connecting the thyristor 25 and the field winding 23 of the AC exciter 6, the same effect as in the present embodiment can be expected.

[0017]

As described above, according to the present invention,
By changing the voltage / frequency (V / f) conversion constant in the automatic voltage regulator (AVR) between the start of the internal pump and the normal operation, the speed increase at the start of the internal pump is suppressed, and the core flow rate is reduced. It is possible to reduce the fluctuation range of the neutron flux, so that the neutron flux rise overshoot can be suppressed and the reactor can be operated stably. Further, according to the present invention, the voltage / frequency (V / f) in the automatic voltage regulator (AVR) is used when the internal pump is started and during normal operation.
By changing the conversion constant, the rise of the internal pump frequency (that is, the speed), the rise of the core flow rate is gradual, and the neutron flux also has a sufficient value for the scram set value. Good internal pump starting characteristics with small bundle overshoot can be ensured. Further, according to the present invention, after the internal pump starts and reaches the minimum pump speed (completion of the speed increase), the conversion of the voltage / frequency (V / f) conversion constant in the automatic voltage regulator (AVR) is performed. Since the value is changed gently, there is no step-like variation in the frequency of the AC generator, and the control at the normal time can be started smoothly. Also,
ADVANTAGE OF THE INVENTION According to this invention, the speed of an internal pump can be suppressed low by the simple structure which only inserts a resistance into the field circuit of the AC generator of the MG set with a fluid coupling, or the AC exciter at the time of starting.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a core flow rate control system showing one embodiment of the present invention.

FIG. 2 is an automatic voltage regulator applied to the present invention.

FIG. 3 is a detailed embodiment of a V / f converter applied to the present invention.

FIG. 4 is a comparison diagram of internal pump starting characteristics between the present invention and a conventional method.

FIG. 5 shows another detailed embodiment of the V / f converter applied to the present invention.

FIG. 6 shows another detailed embodiment of the V / f converter applied to the present invention.

FIG. 7 shows another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 3 AC motor 4 Fluid coupling 5 AC generator 6 AC exciter 8 Field breaker 9 Field winding 11 Reactor 16 Internal pump 23 Field winding of AC exciter 25 Thyristor 100 Automatic voltage regulator 200 V / f converter 201 voltage / frequency conversion constant 202 voltage / frequency conversion constant during normal operation 203 voltage / frequency conversion constant at startup 204 variable constant 210 timer 216 memory 218 change rate limiter 217 monitor

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Naoji Tanikawa 3-1-1 Kochi-cho, Hitachi-shi, Ibaraki Hitachi, Ltd. Hitachi Plant (58) Field surveyed (Int. Cl. ⁷ , DB name) G21C 7/26 G21C 15/243

Claims (8)

(57) [Claims] 1. A drive motor, a fluid coupling, and an AC generator.
Having a variable frequency power supply and installed inside the reactor,
An internal pump driven by the alternator ;
A core flow rate control system including a control device that performs voltage / frequency control of the AC generator, wherein the control device includes:
Voltage / frequency used when starting up the variable frequency power supply
Conversion constants and voltage / frequency conversion constants used during steady-state operation
Core flow rate control system characterized by having a. 2. The variable frequency power supply according to claim 1,
When starting the device, the voltage / frequency used during the steady operation
From the number conversion constant, the voltage / frequency conversion constant
After a predetermined time set in advance,
A core flow rate control system for switching back to a voltage / frequency conversion constant used during operation . 3. The variable frequency power supply according to claim 1,
When starting the device, the voltage / frequency used during the steady operation
From the number conversion constant, the voltage / frequency conversion constant
The internal pump to the minimum speed
When the speed is increased, the voltage / frequency used during the steady operation
A core flow control system characterized by switching back to a conversion constant . 4. The method according to claim 2, wherein
The controller uses time as a voltage / frequency conversion constant as a function
From the voltage / frequency conversion constant used at the time of startup
Can change to the voltage / frequency conversion constant used during steady operation
The variable frequency power supply has a variable constant
Switch to the variable constant until the steady operation
Core flow rate control system characterized by that. 5. The method according to claim 2, wherein
The control device includes a voltage / frequency converter used during the steady operation.
A rate-of-change limiting means for slowly changing a constant,
From the start-up of the variable frequency power supply to the steady-state operation
Until the change rate limit as a voltage / frequency conversion constant
A core flow rate control system characterized by switching to a variable constant output by a means . 6. A drive motor, a fluid coupling, and an AC generator,
Having a variable frequency power supply and installed inside the reactor,
An internal pump driven by the alternator ;
A core flow control system comprising a control device for controlling voltage / frequency of the alternator, wherein the variable frequency power
Source apparatus at the start of the the field circuit of the alternator Lee
Resistance to reduce torque transmitted to internal pump
Core flow rate control system and providing a. 7. A drive motor, a fluid coupling, and an AC generator,
Having a variable frequency power supply and installed inside the reactor,
An internal pump driven by the alternator ;
A core flow rate control system comprising a control device for performing voltage / frequency control of the AC generator, wherein an AC exciter is provided in the variable frequency power supply,
At startup , the internal circuit is connected to the field circuit of the AC exciter.
A core flow rate control system comprising a resistor for reducing torque transmitted to a pump . 8. A drive motor, a fluid coupling, and an AC generator,
Having a variable frequency power supply and installed inside the reactor,
An internal pump driven by the alternator;
From a control device for controlling the voltage / frequency of the alternator
A core flow control system comprising:
When the variable frequency power supply is started, the ratio is lower than during a normal operation.
A core flow rate control system characterized in that a voltage change with respect to a frequency change is reduced .