SU1282294A1 - Self-excited voltage inverter - Google Patents

Abstract

The invention relates to a converter technique and m. used in the mouths of the energy and electroplate drive. The goal is enhanced functionality. The device contains in each phase the main thyristors 11, 12 with the reverse current diodes 9, 10. The secondary half windings 14, 5 of the switching tr-ra 13 are connected in series with the thyristors 11, 12. The primary winding 16 of the tr-ra 13 has a fault circuit 17 and connected to the input terminals via a fixed key 24. To turn off the thyristor 1I, the key 24 closes. In this case, the current from the winding 14 passes at a speed determined by the current drop in the inductance of the strayer to the winding 16. In this case, the thyristor current 11 becomes zero and the opposite voltage is applied to it. e. After the key 24 is turned off, the energy stored in the winding 16 is absorbed by the fault circuit 17. In this case, it is possible to switch the thyristor of one shoulder repeatedly without switching on the thyristor of the other shoulder. -1 hp f-ly, .3 ill. (L

Description

The invention relates to converter technology and can be used in power engineering devices l of electric arc.

The aim of the invention is to expand the functionality by providing independent and multiple switching of each arm of the thyristor} south bridge.

FIG. 1 shows a circuit diagram of a single phase converter in a first embodiment; in fig. 2 is a graphic illustration of his work; lia fig. 3 - main circuit of the converter according to the second variant ..,

The autonomous inverter is connected to the valves -). A rectifier of rectifier through filter 7, 8 and contains vent (diodes) 9 and, 1 O reverse current, main thyristors P and 12, switching transformer 13 with secondary semi-windings 14 and. 5c which are connected in series with the core 5 and thyristors. The first winding 16 of a transformer having a reset circuit 17 (which can traditionally be completed as an additional winding, shunted in series, connected by a diode and acting resistance-), is connected at one end to the positive terminal of the inverter power supply. Circuit 18 is a circuit diagram of a single phase inverter. The circuits 19 and 20 of the two other phases are made ideshpyu. A three-phase load 21–23 is connected to the output points of the inverter. The other end of the winding 16 is connected via a control switch 24 to the negative source.

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I. The converter (FIG. 3) has a switch, made-NEY according to the single-phase tristor bridge circuit on the thyristors (gates) 25-28 with a capacitor 29 and a choke 30 n AC circuit and a counter diode 31 on the DC side.

Consider the operation of the Converter on the example of one phase (scheme 18)

FIG. 2 is a diagram of the current values of voltages and currents, the frequency converter according to the scheme of FIG. . The inclusion of the thyristor 11 is illustrated here. Switching its input is as follows. By the time t, a current i flows. through thyristor 11 and winding transform 14

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five

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five

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torus 13. At time t, key 24 shuts off to turn off 11. While maintaining the total flow in transformer 13 at the moment of key closure

24curts from winding I4 will transfer at a speed determined by the current decay in the inductance of the transformer dissipation into winding 16 (i). In this case, the current of the thyristor 11 becomes equal to zero (the moment t,. The voltage across the load and changes sign) and a reverse voltage U is applied to it, equal in magnitude to the excess voltage in the winding 14 over the supply voltage. The load current will take on the diode 10 (i), the duration of the closed state of the key 24. must be equal to the recovery time of the thyristor I .I spit current switching time from the winding 14 to the winding 16 (interval After turning off the keys 24 (time t) energy, stored in the winding 16, is absorbed by the discharge node 17.

In the diagram of FIG. 3, in the switching node, the idle recharge of the capacitor 29 is eliminated and each recharge of the capacitor is used for switching. Let the capacitor 29 be charged to a voltage approximately equal to the converter power supply. To turn off the thyristor 11, it is necessary, as in the previous schemes, to connect the primary winding of the transformer to the output of the power source. This is done using a diode 31, through which the current of the paresis is flowing - p and the capacitor 29. The diode 31 is connected to the LC circuit or thyristors

25 and 28, or 26 and 27. In this case, the capacitor is recharged each time around a short-circuited circuit: either a capacitor, a 27-choke, a 30-thyristor, a 28-diode, a 31-thyristor 25, or a condenser. Sator 2.9-choke 30-thyristor 27- diode 31-thyristor .26 and every time it turns out after recharging and ready

to the next commutation. The open state of the diode 31. in the time of the recharge 29 corresponds to the closed state of the switch 24 of the circuit (Fig. 1). The excess electromagnetic energy of the transformer 13 is quenched by the drop node 17.

Claims (2)

Invention Formula I, Autonomous voltage inverter containing connected to the outputs To connect the power source, a three-phase tcristor bridge, in series with the thyristors of each phase, includes secondary half-windings of a switching transformer connected to a common point with a corresponding output terminal connected to the three-phase reverse-diode AC outlet, and the primary winding of the switching transformer of each phase is connected with one output terminal. the point of connection of the anodes of the thyristors of the anode group of the bridge, and the other output, with the control key connected to the source of a mutable voltage, characterized in that, in order to expand the functional capabilities, by providing independent and multiple switching of each field of the thyristor bridge; the source of the switching voltage is used as the source of the switching voltage, and the key is connected to the connection point of the cathodes of the thyristors of the cathode group of the bridge. 2. The inverter according to claim I, characterized in that the control key is made in the form of a single-phase thyristor bridge connected by a cathode group to the three-phase thyristor bridge thyristor cathodes and bounced by a counter diode, where the B circuit is connected.