SU463213A1 - Thyristor switching device in frequency converters - Google Patents

Description

one

The well-known thyristor switching devices in frequency converters have a low efficiency due to significant switching losses.

The purpose of the invention is to reduce switching losses.

This goal is achieved by the fact that the common point of junction of the anodes of the diodes and the cathodes of the thyristor bridge are two parallel centers, consisting of droplets and a resistor, the output terminal of the device for. switching of the cathode groups of the power thyristors is connected to the choke, but the opposite end of which is connected to the cathode of the thyristor bridge, and the output terminal for switching the anode groups of the power thyristors connected to another choke, the opposite end of which is connected to the anodes of counter-activated diodes.

The drawing shows a diagram of a thyristor switching device in frequency converters containing anodic and cathodic groups of power thyristors.

The proposed device includes a thyristor bridge, the combined thyristor anodes of which are connected to the positive terminal 1 of the charge source or diode bridge connected to the mains supply, and the combined cathodes to the negative terminal 2 through the thyristor 3, included in

2

a direction with bridge thyristors, a switching capacitor 4, switching chokes 5-7, resistors 8 and 9, oppositely connected diodes 10, 11, as well as reverse diodes 12-14 and a resistor 15.

The operation of the device when switching thyristors of cathode groups begins with switching on thyristors 16, 17 or 18, 19 (depending on the polarity of the charge of the commutating capacitor) and distribution thyristors connected to point 20. Switching off the power thyristors is performed by the synchronizer 4 through included thyristors, chokes 5 and 6, not indicated on the diagram distributive thyristors and a supply bridge diode connected to point 21. Included thyristor 17 or 19, parallel circuits with 6 and 7 chokes and resistors

8 and 9 and one of the oppositely connected diodes 10 or 11 11 form a circuit of the irresistible discharge of the switching capacitor 4. At the end of the switching off time of the comm.mutated thyristors turn on the thyristor 3 and

as well as the included thyristors of the bridge capacitor 4 and choke 5, a dose of a number of switching capacitors occurs.

Reverse diodes 12-14 and resistor 15 are designed to drain the excess power 113 circuit switching.

The excess energy is removed through diode 14, parallel chains 6, 8 and 7, 9, depending on the polarity of the capacitor through diodes 10, 13 or 11, 12 and resistor 15.

When switching the thyristors of the anode group, depending on the polarity of the charge of the capacitor, one of the thyristors 17 or 19 and thyristor 3 is turned off. The power thyristors are turned off by discharge of the capacitor 4 through the choke 5, the connected thyristors, a rectifying bridge diode connected to point 2, distribution thyristors connected to point 21 choke 7 and diode 10 or P. The circuit of the independent discharge of the switching capacitor as well as when switching thyristors of the cathode groups is formed through the thyristor 17 or 19, parallel hibernation 6, 8, 7, 15 and diode 10 or 11. When the turn-off time of the thyristors include switched thyristor 16 or 18 (according to the charge capacitor house) and through the throttle 5 and previously included thyristors happens dozar d commutating capacitor.

4 Subject of the invention

A thyristor switching device in frequency transformers containing anodic and cathodic groups of power thyristors, made in the form of a single-phase bridge circuit, the DC diagonal of which is connected to a recharge voltage source through the thyristor and the AC diagonal of the switching circuit is switched on through the thyristor and counter-connected diodes, characterized in that, in order to reduce switching losses between the common junction point of the anodes of the unique diodes and the cathodes of the thyristor bridge, We have two parallel chains, the state H1, si pz of the throttle and a resistor, the output terminal of the device for switching the cathode groups of the power thyristors is connected to a choke, the opposite end of which is connected to the cathodes of the thyristor bridge, and the output terminal for switching the anode groups of the power thyristors is connected to another choke The opposite end of which is connected with the anodes of the counter-switched diode.

020

01 g