SU598247A2 - Thyristor switching arrangement - Google Patents

Description

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The invention relates to the field of electrical engineering and can be used for switching thyristors in converter technology.

According to the main author. St. .479252 a device for switching thyristors is known, which contains a DC source with a midpoint to which the back plate of the switching capacitor is connected to the common point of two series-connected diodes connected in parallel to the source in the opposite direction, two circuits each of which contains. switched on switching thyristor and transformer winding, the common point of which is connected to another plate of the switching capacitor. Such a device has a large steady-state value of amplitude: the voltage across the switching capacitor.

The aim of the invention is to reduce the steady-state value of the voltage amplitude at the switching capacitor.

This is achieved by the fact that in the proposed device for switching thyristors, a key is connected, connected by one pole k to the input of the charging cable, and the other to the plate of the switching capacitor and the common point. Two diodes connected in series that are connected parallel to the source in the opposite direction.

The drawing shows a circuit diagram of a device for switching thyristors, where 1 is a switching capacitor, 2, 3 are diodes, 4, 5 are a transformer winding, 6, 7 are switching thyristors 8, 9 are source capacitors U, ID is a charging choke 11 is the key.

With; operation of the device, when it is not necessary to limit the voltage rise on the switching condenser 1, the key 11 is closed. At the same time, when the thyristor 6 is turned on, the oscillating charge of the capacitor 1 along the circuit occurs: the source U, the thyristor 6, the transformer winding 4, the key 11, the choke Y. The capacitor 1 is charged at the same time as twice the voltage

At the end of the singing of the source

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The thyristor 7 is switched on in this loop. At the same time, capacitor 1 is recharged along the circuit: transformer winding 5, cyop 3. At that, due to the fact that the diode 3 conducts, the charge gap 10 is found between the midpoint of the power source and its negative pole. The current through the choke 10 begins to increase.

Since the electromagnetic constant of the throttle exceeds the half-period of oscillation of the switching circuit, the current through the diode 3 of the throttle increases more slowly than in the switching circuit, therefore when the current decreases through the diode 3 as the current decreases, the current through the diode 3 drops to zero and the diode will be shifted in the opposite direction. At the same time, the contour reload will change its structure. The end of the recharge process will be the ho circuit: choke 10, power source, thyristor 7, transformer winding 5.

The next switching cycle, when the thyristor 6 is turned on, the recharging process will proceed in a similar way, first charging without a power source, and then with a source. When switching the load current, the voltage on the switching capacitor 1 will increase, since with each switching additional energy is introduced into the oscillating circuit. In order to reduce the voltage growth on the commutation capacitor 1, when the load switches, switch 11 is opened. Now the switching process of each circuit will occur without additional charge from the power source and the voltage amplitude on the switching capacitor will become smaller.

As the key 11, you can use a thyristor or thyristors.

Claims (1)

Invention Formula  A device for switching; thyristors auth. St. / 479252, characterized in that, in order to reduce the steady-state value of the voltage amplitude on the switching capacitor, a key is inserted into it, connected by one pole to the output terminal of the charging droplet, and connected to the common point of the switching capacitor and the common point of the pool connected parallel to the source in the opposite direction.