JPS62217868A - Control device for power source for excitation of superconducting coil - Google Patents

Abstract

PURPOSE:To realize the avoidance of a quench phenomenon and the shortening of an operation time at the same time with simple organization, by varying the values of the input resistance and the charge resistance of an integrator, and by making a current change rate smaller as current is greater. CONSTITUTION:When a current carry-over value is set on a setting unit 1 and the initial reset of an integrating condenser 14 is over, the output of a comparator 11a is saturated at H. Then, an analog switch 13a is cast. The integrating condenser 14 is charged at a specified voltage change rate, and coil current is increased along with the command. After that, if the current exceeds a set value, a switch 13b is cast and the voltage change rate of the integrating condenser 14 is made small. In the same manner, as current gets greater further, the output change rate of the current setting unit is turned smaller further, and the coil current is risen with delay rise. When the coil current comes to a final value set on the level setting unit 1, then a desired current value is kept.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an excitation power source for a superconducting (also referred to as super 1L conductor, but generally referred to as superconducting) coil.

[The street of the subordinates]

As such a power source, there are generally known power sources such as a series regulator as shown in FIG. 7, a thyristor rectifier as shown in FIG. 8, and a chopper as shown in FIG. 9. In addition, in FIG. 7, 1 is a current setting device, 2 is a current regulator (ACR), and 3 is a base MX#! J
J circuit, 4 is a diode rectifier, 5 is a filter, 6 is a transistor, 7 is a current detector, 8 is a freewheeling diode, 9
is a superconducting coil. Further, 6a in FIG. 8 is a gate drive circuit, 3b is a comparator, 3c is a sawtooth wave generator, 4' is a thyristor converter, 3d in FIG. 9 is a triangular wave generator, 6
' is a chopper, and the other parts are the same as in Fig. 7.

Since these devices are generally well known, their explanation will be omitted, but in each case, the value set by the current setting device 1 matches the actual value of m current in the coil 9, that is, the output from the current detector 7. Transistor 6 and rectifier 4, 4'
etc.

[Problem that the invention seeks to solve]

By the way, when such a superconducting coil is excited, a so-called quench phenomenon, in which the superconducting state returns to the normal conducting state, may occur. In order to prevent this quench from occurring, it is conceivable to ensure safety by gradually exciting the current setting device using a ramp function generator or the like to delay the rise of the current. However, in this case, there is a problem that not only does it take time to start up the coil current, but also that it is difficult to monitor it.

Therefore, an object of the present invention is to provide a control device that prevents the occurrence of the quench phenomenon and enables the coil current to rise in a short time.

[Failure to solve the problem]

A setting device that sets the final value of the coil current, an integrator that integrates the current setting value from its initial value to the final value, and a selection section that changes the integral constant of this integrator according to the magnitude of the coil current. establish.

[Operation] In this invention, the critical temperature at which the superconducting state ceases to exist is determined by a strong magnetic field F.
This was done by focusing on the fact that the rate of change in the current set value is reduced as the coil current increases, and the possibility of the quench phenomenon occurring increases. In the low region, the current changes rapidly to shorten the time required to build up (or draw down) the coil current.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the invention.

In the figure, 1 is a current setting device, 2 is a current regulator, 7 is a current detector, and 11a to 11c are comparators.
, 12a to 12c, 17a to 17c are resistors, 13a to 1
3d is a switch, 14 is a capacitor (capacitance is C), 15
is a discharge resistor, 16 is an operational amplifier, 18a
, 18b is an inverter gate, and 19 is an AND gate.

The current detector 7 is composed of a shunt resistor and an amplifier 7a for level conversion as shown in the figure, and the current regulator 2 adjusts the proportional Performs integral (PI) calculation. The level setter 1 sets a desired value as the final value of the rise of the coil current.

On the other hand, the photoelectric resistors 12a to 12C1, the capacitor 14, and the operational amplifier 16 constitute an integrating circuit. The switches 13a to 13c are for selecting the resistors 12a to 12c, and in this case, each resistor 15 a r 13 b
The magnitude of r 13 c [11, 112, [3 is selected so that, for example, R1<R2<R5. The switch 13d is used to initialize the voltage of the integrating capacitor 14, and is turned on at the same time as the switches 13a to 13c are opened.
The voltage of the capacitor is reduced to zero through the . Comparator 1
The output of 1a is 10 when the set value is lower than the integrator output.
-(L)", and when it is high, it becomes "high I()", and the integrator capacitor 14 is switched between discharging and charging.

Setting resistors 17a to 17c are used to determine the current value of the current rate of change, and the current value 11 is determined by the voltage at the connection point of resistors 1711 and 17c, and the current value 2 is determined by the voltage at the connection point of resistors 17a and 17b. We are trying to define each.

Comparators 11b and 11c.

Inverter gates 18a, 18b and AND gate 1
Reference numeral 9 determines the coil current value, that is, determines whether the output of the current detector 7 is larger or smaller than the set value 11 + I2, and switches 15a to 15c are activated according to the output.
Select and drive. That is, when <11, switch 15af is on, 11<I<I
When it is 2, the switch 13b is turned on, and when it is I2, the switch 14c is turned on.

Now, the operation at the time of starting up the coil current when the circuit as described above is used as the current regulator shown in FIGS. 7 to 9 will be described with reference to FIG. 2.

When the final current value has been set in the setting device 1 and the initial reset of the integrating capacitor 14 has been completed, the comparator 1
The output of 1a is saturated at ``H''. At this time, the output of the integrator is ``0'' and the desired current value is 0'', so the analog switch 13a is turned on. Therefore, the integrating capacitor 14 is 1 /CR1, and the coil current I increases in accordance with the original command (see Figure 2).

Next, when the current exceeds the set value 1, the switch 13
b is turned on, the voltage change rate of the integrating capacitor 14 becomes 1/CR2, which is smaller than 1/CR1 (see Figure 2 @ Diagnostics). Similarly, when the current I exceeds 2, the rate of change in the output of the current setter changes to a smaller value, and the coil current rises slowly (see θ in FIG. 2). When the coil current reaches the final value set by the level setter 1, the -x7 palator 11a starts to repeat inversion between H and L, and the integrator 16 also remains constant without discharging. The voltage is maintained at the desired current value. Incidentally, when drawing out the coil current, the setting value of the level setter 1 is simply set to zero, and the operation is reversed to that described above, and the operation of tracing the elapsed time in FIG. 2 in reverse is performed.

FIG. 6 is a circuit diagram showing another embodiment of the invention.

That is, in the embodiment shown in FIG. 1, the current change rate is changed by switching the photovoltaic resistor, whereas
In this embodiment, the input voltage of the integrator is changed to increase the rapid rate of change of the 'rit flow, so that the rate of change changes continuously. Furthermore, taking advantage of the fact that the safety against the quench phenomenon is slightly higher when current is drawn, the integrator input voltage can be changed between when the current is started up and when the current is drawn.

This point will be explained in more detail. In FIG. 5, the current regulator 2, current detector 7 and integrator are connected to the first
It is similar to the figure. However, the difference is that the switch 13a is opened only at the initial time when the switch 13d is turned on. In addition, a limiting resistor 17 and a Zener diode 2 provided after the comparator 11a
0a.

20b is for changing the saturation value, 20a and 2
By making the zener voltage of 0b different, the operating time during charging and discharging is changed. moreover,
The input voltage of the integrator is made to decrease as it approaches the current value set by the resistors 22a, 22b and the operational amplifier 21a. The resistor 23a calculates the current difference for this purpose.

23c and an operational amplifier 21b, whose outputs are sent to a Zener diode 20a by a multiplier 24.

By multiplying by the voltage value saturated with the Zener voltage of 20b, 1 can obtain an integrator input proportional to the difference. Incidentally, the change in the coil current in this case is illustrated as shown in FIG. 4, for example.

Here, if you choose Zener diodes 20a and 20b with the same Zener voltage, you can make the current rise and current draw times the same, and if you choose Zener diodes 20a and 20b with different Zener voltages, you can make these times different. It is possible to

Does the above mean current startup? We have described a volatilization method for a LIi source that has two modes of uIt extraction.

Next, a case where a current stop period is provided in the middle as shown in FIG. 6, and a permanent switch consisting of a superconductor and a heater is inserted instead as shown in FIG. 5 will be explained.

In the operation of such a power supply, in addition to the above-mentioned two operating modes of starting and drawing the coil current, two operating modes of power supply disconnection and reparalleling are added as shown in FIG. Note that the DC power supply 4' shown in FIG. 5 is the same power supply as that shown in FIGS. 7 and 8 above.

Now, looking at the power disconnection mode, when the output of the DC 1 source 4'' shown in Figure 6 (A) is large, the permanent switch 10 is in a highly safe area against the quench phenomenon, and the output vehicle flow is When it is small, the current of the permanent switch 10 shown in Fig. 6 (c) is large and there is a high risk of quenching.This is also the case in the power supply re-parallel mode, and the current rise and draw of the previous coil current is the same. Conversely, when the output current of the power supply, that is, the output of the current detector 7, is small, it is necessary to suppress the current change rate, but this is easy to do; for example, in the case of Fig. resistance 17
By providing another set of circuits similar to a to 17c and comparators 11b and 11c and reversing the correspondence with the switches 13a to 13c, desired operation can be achieved. In addition, in the case of FIG. 6, the resistor 22a
, 22b to a positive value close to zero, and by inserting an inverting amplifier on the output side of the amplifier 21b, which changes the sign of the output of the operational amplifier 21b. Note that these circuits can be easily switched by providing a switch or the like that operates with a signal having the same timing as the operation signal of the permanent switch circuit.

〔Effect of the invention〕

According to this invention, by changing the values of the input resistance and charging resistance of the integrator, it is possible to reduce the rate of current change when a large current is applied, and as a result, it is easy to avoid the quench phenomenon and shorten the operation time. This has the advantage that it can be realized simultaneously with a different configuration.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of this invention, Fig. 2 is a graph for explaining its operation, Fig. 3 is a circuit diagram showing another embodiment of this invention, and Fig. 4 shows its operation. Graphs for explanation; Figure 5 is a schematic diagram showing the configuration with a permanent switch; Figure 6 is a waveform diagram of each part to explain its operation; Figure 7 is a conventional control device using a series regulator. FIG. 8 is a schematic diagram showing a conventional example of a control device using a thyristor rectifier, and FIG. 9 is a schematic diagram showing a conventional example of a control device using a chopper. Symbol explanation 1...Current setting device, 2...Current regulator (ACR), 2 a + 7 a * 16 + 21
a + 2 l b...”...amplifier, 3...
...Pace drive circuit, 3a...Gate drive circuit, 3b, 11a to 11c...Comparator, 3
c...Sawtooth wave generator, 3d...Triangular wave generator, 4゜4', 4"...DC power supply, 5.
...Filter, 6...Transistor, 6
'...Chopper, 7...Current detector,
8...Freewheeling diode, 9...Superconducting coil, 10...Permanent switch, 12a-12
ct15゜17+ 17a~17cy22a*22b
+23a to 23c...Resistance, 16a to 13d.
...Switch, 14...Capacitor, 1
8ae18b...Inverter gate, 19...
...AND gate, 20a*2ob... Zener diode, 24... Multiplier. Agent Patent Attorney Akio Namiki Agent Patent Attorney Kiyoshi Matsuzaki Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claim] A control device that excites a superconducting coil via a current regulator that performs adjustment calculations to match a detected current value with a set value, comprising: a setting device that sets a final value of the current; A superconductor comprising: an integrator that integrates a set value from its initial value to its final value; and a selection unit that changes an integration constant of the integrator in accordance with the magnitude of the coil current. Control device for coil excitation power supply.