JPS6231591B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thyristor power supply control device, and particularly to a thyristor power supply control device suitable for use in a power supply facility in which a portion of a thyristor bank is operated as a bypass pair.

There is power supply equipment that improves the power factor at low loads by configuring a plurality of thyristor valves and operating some banks as bypass pairs. For example, in a nuclear fusion device, after the current rises during plasma generation, the load becomes low. If a plurality of banks are operated during this low load state, the power factor will deteriorate, but if the number of operating banks is reduced, the power factor will improve even under low load conditions. Such operation is called bypass operation.

FIG. 1 is a block diagram of a conventional thyristor power supply control device. The example shown in FIG. 1 is an example of two banks.

The load current _Id is detected by the load current detector 1, compared with the control target current command _Iref , and the deviation ΔI is sent to the thyristor bank via the controller 2 and phase control circuits 3a and 3b, which are composed of PIDs. 4a and 4b are driven. Each thyristor bank is supplied with AC power E, and the outputs of the two thyristor banks are connected in series, and these outputs E _d1 , E
The sum E _d of _d2 is supplied to the load Z.

The relationship between the thyristor control angles α ₁ and α ₂ and the thyristor voltages E _d1 and E _d2 is expressed by the following equation.

(However, P is the number of phases.) In this case, since there is only one controller 2, there is a relationship of cosα ₁ =cosα ₂ and E _d1 =E _d2 , and the load is shared equally. Further, the load terminal voltage E _d is E _d =E _d1 +E _d2 =2E _d1 =2E _d2 .

FIG. 2 a, b, c, d, e, f, and g show the response characteristics of each part in the device shown in FIG. The example shown in the figure shows the thyristor valve 4a during 50% load operation,
100% by bypass pair operation on 4b side of 4b
This is a case where the 4a side is brought into conduction and the 4a side is changed from 25% operation to 50% operation. The time t ₁ shown in the figure is the time when the bypass pair is executed. By executing this bypass pair, a voltage fluctuation occurs in the thyristor bank 4a, and as a result, the load voltage E _d also changes from a maximum of 50% to 25%, as shown in FIG. 2f.
This change will eventually occur due to the feedback control system.
Although it will recover to 50%, fluctuations in the load current cannot be avoided. The cause of this is due to the characteristics of the controller 2. Although the gain is increased to improve the responsiveness of the system during normal times, this appears as an overresponse during bypass pairing.

An object of the present invention is to provide a thyristor power supply control device that reduces fluctuations in load current that occur during bypass pair operation and achieves good control characteristics.

The present invention simultaneously raises the output of the controller to a value equivalent to the load current immediately before the start of the bypass pair operation, eliminates changes in the load voltage, and then gradually reduces the raised external control signal. By automatically switching the controller output and its external control signal without bumping using a high value selection circuit, fluctuations in load current are reduced.

FIG. 3 is a block diagram showing an embodiment of the present invention. Also, Fig. 4 a, b, c, d, e, f, g,
h, i, and j are response waveform diagrams of each part of the embodiment of FIG. 3.

The embodiment shown in FIG. 3 is based on the circuit shown in FIG.
This configuration includes a bypass pair controller 6 consisting of a PID, a function generator 7, relay contacts 8a, 8b, 8c driven by bypass pair commands, and a high value selection circuit 9. The bypass pair controller 6 calculates cos α _B1 based on the output I _d of the current detector 1.
has a control function so that it always matches I _d , and its output is cosα _B1 relay contact 8a,
It is applied to the high value selection circuit 9 via the adder 10. Further, the output cosα _B2 of the function generator 7 is sent to the adder 10 via the relay contact 8b, and the adder 10 obtains cosα _B.

The status of each relay contact before bypass pair operation is as follows.

8a: OFF, 8b: OFF, 8c: ON In addition, these relay contacts are as follows at the same time as the bypass pair.

8a: ON, 8b: ON, 8c: OFF Bypass pair controller 6 has its output cos
The function generator 7 is controlled so that α _B1 always matches the load current I _d , and the function generator 7 is operated simultaneously with the bypass pair to increase the signal in a ramp-like manner from 0%. The rising speed is the controller 2
It should be possible to follow the data sufficiently.

In FIG. 3, before the bypass pair is executed, control is executed that depends only on the output of the controller 2, and the output cosα of the high value selection circuit 9 is 25% of the same value as the output cosα ₀ of the controller 2, and the load voltage E _d is controlled at 50% of E _d1 +E _d2 and the load current is controlled at 50%. At this time, the output cosα _B1 of the bypass pair controller 6 is 50%, which is the same as I _d , but since the relay contact 8a is OFF, the output of the function generator 7 is
The mismatch cosα _B with cosα _B2 is always 0%, and the high value selection circuit 9
α ₀ is always selected.

Next, when the bypass pair command BP is issued, relay contacts 8a and 8b turn ON and relay contact 8c turns OFF, so that cosα _B (cosα _B1 − cosα _B2 ) becomes 50%, raising cosα to 50%. It will be done. In other words, the thyristor bank 4b becomes a bypass pair, and when E _d2 =0, E _d1 =50%, so that the load voltage E _d does not change and the load current I _d does not change either.

After that, by increasing the output cosα _B2 of the function generator 7, the mismatch signals cosα _B and cos
α decreases and cos α ₀ increases. cos α ₀ =
After cosα _B , the thyristor is controlled by the controller 2 and returns to its normal state.

FIG. 5 is a block diagram showing another embodiment of the invention. Also, Fig. 6 a, b, c, d, e, f,
g, h, and i are response waveform diagrams of each part of the embodiment of FIG. 4.

This example is an example using a low value selection circuit,
This is used to cancel the bypass pair operation, and is designed to reduce the output of the function generator. As for the configuration, a low value selection circuit 11 is provided between the controller 2 and the phase control circuit 3b in the device shown in FIG. is applied to the low value selection circuit 11. The low value selection circuit 11 selects the lower of the output cosα ₀ of the controller 2 and the output cosα _B1 of the function generator 7 and outputs it as cosα ₂ .

As shown in FIG. 6, the bypass controller 4a
When the bypass controllers 4a and 4b share 25% each due to the parallel entry command BP during 50% operation, when the parallel entry command BP is issued at time _t2 ,
From this point on, the output of the function generator 7 increases, and the output _cosα0 of the controller 2 conversely decreases. Until time t ₃ , the output cosα _B2 of the function generator 7 is selected by the low value selector 11, and this selected output cos
The phase control circuit 3b is controlled by _α2 , and the thyristor bank 4b is driven. Control signal cosα
₁ and cos α ₂ do not show sudden changes, it can be seen that both the load current I _d and the load voltage E _d do not fluctuate and are stable, as shown in FIG. 6h and i. This embodiment can be combined with the embodiment of FIG.

As is clear from the above, according to the present invention, fluctuations in load current during bypass pairing can be minimized.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional thyristor power supply control device, Fig. 2 a, b, c, d, e, f, and g are response characteristic diagrams of each part in the device of Fig. 1, and Fig. 3 is a diagram of a conventional thyristor power supply control device. Block diagram of the embodiment, Fig. 4 a, b,
c, d, e, f, g, h, i, j are response waveform diagrams of each part of the embodiment in Fig. 3, Fig. 5 is a block diagram of another embodiment of the present invention, Fig. 6 a, b ,c,d,e,
f, g, h, and i are response waveform diagrams of each part of the embodiment shown in FIG. 1...DC current detector, 2...Controller,
3a, 3b...Phase control circuit, 4a, 4b...Thyristor bank, 5...Load (Z), 6...Bypass pair controller, 7...Function generator, 8
a, 8b, 8c, 12...Relay contact, 9...High value selection circuit, 10...Adder, 11...Low value selection circuit.

Claims (1)

[Claims] 1. Controls the current or voltage of the load by controlling the phase of a plurality of thyristor banks based on a target command and a feedback signal from the load, and at least one of the plurality of thyristor banks when necessary.
A thyristor power supply device that enables bypass pair operation with respect to a base, a bypass pair controller that adjusts the feedback signal to a constant value, a function generator that generates a signal that increases in a ramp shape, and a function generator that generates a signal that increases in a ramp-like manner. A means for generating a deviation between the output and the output of the bypass pair controller based on the bypass pair command, and selecting the higher value of either the deviation by the means or the output of the controller for normal control based on the target command and executing the bypass pair. A thyristor power supply control device comprising: a high value selection circuit that issues a control command to a non-bypass pair of thyristor banks; 2. Controls the current or voltage of the load by controlling the phase of a plurality of thyristor banks based on a target command and a feedback signal from the load, and at the same time controls at least one of the plurality of thyristor banks when necessary.
A thyristor power supply device that enables bypass pair operation with respect to a base, comprising: a bypass pair controller that adjusts the feedback signal to a constant value; a first function generator that generates a signal that increases in a ramp-like manner; A means for generating a deviation between the output of the generator and the output of the bypass pair controller based on the bypass pair command, and a bypass by selecting the higher value of either the deviation by the means or the output of the controller for normal control based on the target command. a high value selection circuit that generates a control command for the thyristor bank of the non-bypass pair when the pair is executed; a second function generator that generates a signal that increases in a ramp shape based on the parallel input command; and an output of the function generator or A thyristor power supply control device comprising: a low value selection circuit that selects one of the low values of the outputs of the controller and uses it as a control command for a parallel thyristor bank.