CS206866B1 - Self commutation converter connexion - Google Patents

Description

The invention relates to the connection of a self-commutating inverter whose output terminals are connected to two DC supply terminals each with two main thyristors.

; The application of self-commutating inverters causes a greater number of active and passive components than external commutating inverters. This problem is particularly acute in the case of reversible DC pulse converters and especially inverters. For applications of these inverters on traction vehicles, the issue of limiting active and especially passive components is a matter of fundamental importance.

The known inverter connections do not save passive components in particular. In current inverters, either the weight of the commutating capacitors for capturing reactive energy is increasing or the weight increases. in addition, another capacitor load converter from where reactive energy is either dissipated into resistors or; usefully in the power supply by means of another controlled inverter, thus involving considerably demanding dimensions, cost and weight. With voltage inverters known connections are! the effort to limit the dimensions and weight of commutating capacitors by using group commutation. But here too: problems arise. In group commutation ^one ; It is necessary to separate the bridge of the main thyristors from the bridge of the reverse diodes through which the current of the commutation circuit is transferred here. In the circuit used so far, this is done by inductors connected to the individual phases of the inverter. Their dimensions and weight are considerable, as they must be; dimensioned for phase and commutation current. In addition : quenching reactive losses in phase voltages and leads! circuit currents. For that reason ; their inductance cannot be chosen optimally in terms of | the commutation capacity increases and the inverter tripping capacity is increased! limited.

All of these problems are solved by the connection of the Intuitive commutating inverter according to the invention whose essence. it consists in that the reverse diodes of the converter are connected to the two DC supply terminals;

; the poles are of opposite polarity to the main thyristors and the remaining pole of each reverse diode is over at least j; one commutating thyristor connected to at least;

• one inverter output terminal. Commutation circuits are connected to the common node j of the return diodes and commutating thyristors, which have at least one power terminal connected to at least one DC power supply terminal..

It is preferred that the at least one commutation circuit is connected by a commutation terminal via at least one decoupling thyristor to at least one common return diode and commutation thyristor node.

Wiring a self-commutated inverter according to the invention preserves the advantages of a voltage inverter including the possibility of pulse width modulation, but eliminates phase inductances and reduces the number of passive components using group commutation. In some embodiments of the invention, the number of active components of the inverter can also be reduced. ^f The accompanying drawings are depicted variations of self-commutated inverter according to the invention. Fig. 1 is an example of a single phase circuit of a converter with two commutation circuits; Fig. 2 is another example of a single phase circuit of a converter where one commutation circuit and decoupling thyristors are used.

Figures 3 and 4 show examples of the connection of three-phase bridge inverters with group commutation. An example of the connection of a split-phase inverter suitable for higher outputs is shown in Fig. 5.

the circuit according to the invention is used in an example of a four-quadrant DC reverse pulse converter.

The basic function of the self-commutated inverter according to the invention will be described according to Fig. 1:

The main thyristors 1, 1 'with series inductive protective inductors 2, 2' form one phase of the converter, for example an inverter. The reverse diodes 3,3 'are connected to the DC supply terminals 4, with opposite polarity to the main thyristors 1, 1'. The remaining poles of the reverse diodes 3, 3 'are connected to the output terminal 6 via the commutating thyristors 7,7'. Two commutation circuits 8, 8 'serving to trip the main thyristors 1,1' are connected between the DC supply terminals 4, 5 and the common nodes 9, 9 'of the diodes 3,3' and the commutation thyristors 7,7 '.

If, for example, the first main thyristor 1 conducts current I from the positive DC supply terminal 4 via the first protective inductor 2 to the output terminal 6, it can be switched off by the first commutation circuit 8, whose commutation terminal 10 has a positive potential against its supply terminal 11 The discharge from the first commutation circuit 8 suppresses the current j of the first main thyristor 1 and transfers it to the first commutation thyristor. the first commutation circuit 8 by way of: positive DC supply terminal 4, the first commutation circuit 8, the first commutation thyristor 7, the output terminal 6. The positive potential at the commutation terminal 10 of the first commutation circuit 8 creates a protection time for the first main thyristor 1 being switched off. With the current of the load on the positive polarity of its supply terminal 11 and the negative polarity of the commutation terminal 10, this voltage is equal to the voltage at the DC supply terminals 4, 5, the first reverse diode 3 is switched on and the reactive load is transferred from the negative DC supply. terminals 5 via the first reverse diode 3, the first commutation thyristor to the output terminal 6.

Then, the first main thyristor 1 can be switched again, with pulse width modulation, by the circuit: positive DC supply terminal 4, first main thyristor 1, first protective inductance 2, first commutating thyristor 7, first-reverse diode 3, negative supply ₍ DC terminal 5) The reactive current in the first reverse diode 3 and the first commutating thyristor 7 is interrupted and the active current line is continued from the positive DC terminal 4 to the output terminal 6. The whole process can be repeated and thus pulse control the current flowing to the output terminal 6.

For opposite polarity of current there is a second main thyristor 1 'with a second protective inductance 2', a second commutation circuit 8 ', a second commutation thyristor 7' and a second reverse diode 3 '. The reversal of the output current direction is as follows: the first main thyristor 1 has been switched off by the first; by means of a commutating thyristor 7, so that reactive current to the output terminal 6 flows from the negative DC supply terminal 5 through the first reverse diode 3 and the first commutating thyristor 7. The second main thyristor 1 ' closes immediately after reactive current dissipation in the first reverse diode 3 and in the first commutation thyristor 7.

The benefit of the disclosed circuitry over known solutions is that when the first commutator is overcharged; the external circuit 8 does not apply its second shunt; a reverse diode 3 'which is separated by at least one non-conducting commutating thyristor

- in this case 7 '. The inductances for overcharging the commutation circuits are optimally solved directly in them and need not be connected to the inverter phases, as is the case with known wiring.

Giant. 2 shows a circuit of a self-commutating converter according to the invention, in which, in contrast to FIG. 1, a common commutating circuit 8 is used to turn off both polarities of the output current. In addition, 12.12 'separating thyristors are used for alternating tripping of the upper and lower branches of the drive. The separating thyristors 12, 12 'are connected between the nodes 9, 9' of the return diodes 3, 3 'and the commutating diodes. of the thyristors 7.7 'and the commutation terminal 10 of the commutation The various economical possibilities of the invention according to the invention for particular inverters are shown in the following figures.

FIG. 3 shows a three-phase bridge inverter with one commutation circuit 8, particularly suitable for rectangular control, without pulse output voltage control. and

In order to illustrate the corresponding relationships between: Fig. 1 and Fig. 3, the phases R, S, T have been marked in Fig. 3 and the elements therein have been coincident with the phase in Fig. 1. 3 '. The reactive currents of the individual load phases transfer with them commutation thyristors 7, 7 'in series for each of the two phases, which in turn block the undesirable shunt of the commutation circuit 8 during overcharging. For example, for the output terminal 6 in phase R, the active current from the positive DC supply terminal 4 through the first main thyristor 1 and the first protective inductance 2 is switched off at polarity and at the commutating capacitor 80 by closing the trip thyristors 81 and 83. R. undesired shuntování commutation circuit 8 a second freewheeling diode prevents 3'J nonconductive second commutating thyristor 7 'Ί again in phase R. Upon current interruption the first main thyristor 1 I overcharges the commutation capacitor 80) over ^one second, GTOs 81 and 83 and the first ί: commutating thyristor 7 with a load current to the output terminal 6, phase R, as well as an oscillating circuit consisting of over-voltage inductance 85 and over-voltage diode 86. After overloading of commutating capacitor 80 to the DC supply voltage | terminals 4, 5 in polarity β First return is switched on; diode 3 and conducts reactive current to the output terminal 6, phase R, from the negative DC supply terminal ξ 5 via the first commutating thyristor 7. Tripping thyristo-; ty 81; 83 open. With opposite current polarity; in the same phase, the second main thyristor 1 'is switched on and is switched off at the polarity β of the commutation circuit 8 by the tripping thyristors 82, 84 and the second commutation thyristor! 7 '. The first commutation thyristor 7 now blocks the undesirable shunt of the commutation circuit 8 by the first j by the reverse diode 3. The reverse direction of the reactive current is taken by the second reverse diode 3 'spplu with the second commutation thyristor 7'.

The advantage is in addition to removing the oscillating inductances from the converter phases, the 2.2 'protective inductors have a small value, while saving the number of reverse diodes.

FIG. 4 shows a three-phase bridge inverter which is suitable for pulse width control of the output voltage. With pulse width modulation of voltage, there is a need to switch off the main thyristor 1 of two phases, for example RaS at time, the poisons of the third phase T lead to the output terminal 6 a reactive current through the first reverse diode 3 and the first commutation thyristor. The 12.12 'decoupling thyristors are used. '' _J ('| 206867

In the selected example, when switching off the first main thyristors 1 in phases R and S, for example, the trip thyristors 81, 83 in the first commutation circuit 8, the first decoupling thyristors 12 corresponding to the R and S phases and the first commutation thyristors 7 switch again in the RaS phases. the T-phase thyristor separates the first commutating thyristor 7 and the first T-phase reverse diode 3 conducting the reactive current from the first commutation circuit 8.

FIG. 5 shows an example of a high power inverter with each separate phase being fed; a single-phase bridged circuit consisting of four main thyristors: 1.1 in the upper and 1 ', Γ in the lower branches, four commutating thyristors 7, 7', 7, 7 'and two reverse diodes 3.3'. Separating thyristors 12, 12 'are also used for each phase. With this connection, it is possible to achieve twice the power compared to the example of FIG. 4 without the parallel connection of the main thyristors and with the same commutation circuits of the same size.

Use of the circuit according to the invention for four quads; rant DC reversing pulse converter uka-! Fig. 6 is used for one direction of travel. a pair of commutating thyristors also first and third 7 and 7 '. For the opposite direction of travel, the second and fourth main thyristors 1 'and 1 and the second and fourth commutation thyristors 7' and 7 are used. A pair of reverse diodes 3,3 'serve both directions of travel. '

The main advantage of the self-commutating inverter according to the invention is the removal of inductances from the inverter phases. Other advantages are the saving of active and passive components.

Claims (2)

SUBJECT OF THE INVENTION I 1: Connection of the inverter, with its own commutation, whose! The output terminals are connected to two DC power terminals, each with two main ‘thyristors, characterized in that the reverse diodes (3, 3 ') of the inverter are connected to the two DC power supplies; terminals (4,5) of poles of opposite polarity to the main thyristors (1,1 ') and the remaining poles of each return; the diodes (3, 3 ') is connected via at least one commutating thyristor (7,7') to at least one output 5 of the converter terminal (6), and to the common nodes (9,9 ') of the reverse diodes (3, 3') and commutating thyristors (7, Commutational terminals (8, 8 ') are connected to the commutating terminals (10, 10') and at least one power terminal (11, 11 ') is connected to at least one inverter power terminal (4, 5). 2. A self-commutating converter circuit according to claim 1, wherein at least one commutation circuit (8) is connected via the commutation terminal (10) via at least one decoupling thyristor (12, 12 ') to at least one common node (9.9'). ) a reverse diode (3, 3 ') and a commutating thyristor (7, 7').