SK7712001A3 - Power converter circuit and method for connecting to an electrical supply network - Google Patents

Abstract

The circuit has at least one sub-converter system with sub-converters each connected to a transformer that can be connected to an a.c. supply and to intermediate d.c. circuits. One intermediate d.c. circuit can be connected to a d.c. supply. Configuration switches and an isolation switch are connected between first and second intermediate d.c. circuits. The circuit has at least one sub-converter system (5) with sub-converters (5.1,5.2) each connected to a transformer (7) that can be connected to an alternating supply (2) on the a.c. side and to intermediate d.c. circuits (14.1,14.2) on the d.c. side. One intermediate d.c. circuit can be connected to a d.c. supply (1). Configuration switches (10.1,10.2) are connected between the first connections of the intermediate d.c. circuits and between their second connections and an isolation switch (11) is connected between the second and first connections of the first and second intermediate d.c. circuits. Independent claims are also included for the following: a method of coupling to an electrical supply network.

Description

Technical field

The invention relates to a transducer charging network, a section formed by a transducer section, of an AC power side. In particular, a circuit for connection to an electrical which has at least one converter assembly by a first converter section and a second converter section each connected to a voltage to a respective winding may be connected to a power supply is connected to a connection to a transformer which alternating voltage and a first converter section side of the uniform voltage to the first and second uniform voltage, the uniform intermediate circuit of the first second transducer to the first and the uniform uniform uniform section is the second voltage, the voltage voltage.

a connected connection to and one is possible on the other side of the two to connect the intermediate voltage of the circuit of the intermediate circuits to the power supply. The invention of a charging network.

also relates to a method of connection to an electrical

BACKGROUND OF THE INVENTION

For multi-system applications, in particular for long-distance links, rolling stock must draw its propulsion energy from the DC and AC networks, using a network of different DC voltage circuits to supply mains voltage. This requires to be connected both to an AC network that can and to the voltage of conventional traction drives with the respective driving energy.

This converter circuit in the patent specification

DE 196

550th

is described

For example, the converter circuit has two converters, AC voltage. The second wherein the first by means of a transformer to a converter is connected on the AC side to an electrical device the converter is connected to the network side of the network or to an electrical load, in particular to at least one electric motor.

Both converters, through their converter circuit, are connected to the intermediate circuit by one capacitor connection for a uniform voltage of equal voltage, which intermediate circuit, such as a stack or at least

Furthermore, the intermediate circuit is a uniform energy storage device.

t voltage is applied when the converter circuit is supplied from said DC voltage network.

to this network of equal voltage with energy

The transducer circuit according to DE 196 09 550 must be arranged separately for the selected supply network, in any case for operation using a DC voltage network and also using an AC voltage network. For this purpose, the first section switches are arranged on the alternating voltage side between the transformer and the first transducer, the second section switches being arranged between the second transducer and the electrical load.

By correspondingly switching off and on the corresponding section switches in the unpowered state of the circuit, the transducer circuit can be connected both to the DC voltage and the AC voltage, and in this case, if the transducer circuit is operated using the DC voltage network, a second converter, both of which are operated as DC to AC converters.

When the transducer circuit is operated using an AC voltage network, the first transducer is operated as a line transducer that supplies power to the intermediate voltage circuit and from which the second transducer feeds the electrical load.

In the case of such a converter circuit, it is problematic that it is necessary to use a large number of section switches whose position must be re-arranged in the event of a change in the charging network, for example from a DC voltage network to an AC voltage network.

However, this large number of section switches causes a significant increase in component cost, while also requiring a large amount of space, but the space available is extremely limited in the case of converter circuits for traction applications in electric rolling stock.

In addition, the function of the circuit breakers must be properly ensured, in particular by very intensive maintenance of the circuit breakers themselves and also by activating them, since failure of the rail vehicle due to incorrect arrangement of the converter circuit and the location of the circuit breakers leads to further cost increase.

SUMMARY OF THE INVENTION

The object of the invention is therefore to develop a transducer circuit and method of connection to the electric charging network so as to enable it to achieve a very simple and particularly space-saving construction of the transducer circuit for connection to an electrical charging network ^in, the transducer circuit would be operated with minimal number of parts requiring frequent maintenance.

It is also an object of the present invention to provide a method by which a connection to an electric charging network can be made in a very simple manner.

In accordance with the present invention, the above objects have been accomplished by providing a converter circuit for connection to an electric charging network having at least one set of converter sections formed by a first converter section. and a second transducer section, each transducer section being connected on the AC voltage side to a respective transformer winding that can be connected to the AC power source, and the first transducer section being connected on the uniform voltage side to the first and second terminals of the first intermediate DC voltage circuit. wherein the second transducer section is connected on the DC voltage side to the first and second connections of the second intermediate voltage circuit, and one of the two intermediate voltage circuits can be connected to the mains voltage source.

A respective configuration switch is provided between the first connection of the first intermediate voltage circuit and the first connection of the second intermediate voltage circuit and between the second connection of the first intermediate voltage circuit and the second connection of the second intermediate voltage circuit, the section switch being arranged between the second connection the DC voltage circuit and the first connection of the second intermediate voltage circuit.

The configuration switches are preferably designed as mechanical or electronic switches.

The section switch is preferably designed as a mechanical or electronic switch.

At least one load converter a. second connections. even voltage.

The associated one is connected between the first intermediate circuitry

The load transducer is connected to the AC voltage side.

to the electrical load

The electrical load is a winding of a rotating electrical machine, preferably.

triphase partial

Three-phase disconnect arranged between the converter.

the switch is a triphasic partial winding and a load

The converter circuit according to the invention preferably further comprises at least one auxiliary converter connected indirectly to the at least one converter section.

The auxiliary converter is connected, in particular electromagnetically, to the at least one converter section by means of at least one winding of the transformer.

In accordance with another aspect of the present invention, a method for connecting to an electrical charging network has also been further developed, comprising the following steps:

step SI - connecting the AC power source via the AC power switch to the transformer and the converter circuit, wherein the converter circuit comprises at least one set of converter sections formed by a first converter section and a second converter section, each converter section being connected on the AC side of the transformer , and the first converter section is connected on the equal voltage side to the first and second connections of the first intermediate voltage equalization circuit, the second converter section is connected on the equal voltage side to the first and second

I, connecting the second intermediate voltage circuit, or step S2 - connecting one of the two intermediate voltage circuits of the converter circuitry assembly to the mains voltage supply by the mains voltage switch, the method comprising the following additional steps:

step SI.2a - switching the intermediate voltage circuits of the converter system in case of connecting the converter circuit to the AC power supply (step SI) in such a way that there is no direct connection between the intermediate voltage circuits, or step S2.2a - switching If the converter circuit is connected to a mains voltage source (step S2), in such a way that there is a direct connection between the intermediate voltage circuits.

The method of the invention preferably comprises the following additional steps:

steps S1, S1.2a - in the case of connecting the converter circuit to the AC power supply, step s1b - disconnecting the configuration switches arranged between the first connection of the first intermediate voltage circuit and the first connection of the second intermediate voltage circuit, and between the second connection of the first the intermediate intermediate voltage circuit and the second intermediate voltage intermediate circuit connection, and step S1.2b - disconnecting a section switch arranged between the second intermediate voltage intermediate circuit second connection and the second intermediate voltage intermediate circuit first connection.

The method of the invention preferably comprises the following additional steps:

steps S2, S2.2a - in case of connecting the converter circuit to the mains voltage source and in case the mains voltage is significantly higher than the intermediate circuit voltage for the intermediate voltage circuits, step S2.2b - disconnecting the configuration switches arranged between a first connection of a first intermediate voltage circuit and a first connection of a second intermediate voltage circuit, and between a second connection of a first intermediate voltage circuit and a second intermediate voltage circuit connection, and a step S2.2b - switching the intermediate circuit breaker arranged between the second switch voltage and the first connection of the second intermediate voltage circuit.

The method of the invention preferably comprises the following additional steps:

) steps S2, S2.2a - in the case of connecting the converter circuit to the mains voltage source and in case the mains voltage is of the intermediate voltage of the intermediate circuit of the intermediate voltage circuits, step S2.2b - switching on the configuration switches arranged between the first connection a first intermediate voltage circuit and a first connection of a second intermediate voltage circuit and a second connection of a first intermediate voltage circuit

I and the second connection of the second intermediate voltage circuit, and step S2.2c - disconnecting the section switch arranged between the second connection of the first intermediate voltage circuit and the first connection of the second intermediate voltage circuit.

The method of the invention preferably comprises the following further step:

step S1 - in the case of connecting the converter circuit to the AC power supply, step S1 - supplying the auxiliary converter from the AC power supply via a transformer.

The method of the invention preferably comprises the following further step:

step S2 - in the case of connecting the converter circuit to the mains voltage source, step S2.1 - supplying the auxiliary converter via at least one converter section.

The method of the invention preferably comprises the following further step:

in the event of a failure of the converter circuit elements, steps S1.2c, S2.2d - disconnecting the electrical load supplied indirectly and / or directly through the damaged elements of the converter circuit.

The transducer circuit of the present invention has a minimum number of switches, which allows the transducer circuit to be connected to an AC voltage but a DC voltage network. In addition, the converter circuit according to the invention comprises at least one set of converter sections having in each case a first converter section and a second converter section.

As a result of the solution according to the invention, a very simple and space-saving design of the converter circuit has been achieved. In addition, the converter circuit according to the invention makes it possible to minimize the use of very maintenance-intensive components, in particular switches.

According to the invention, in the case of connection to an AC voltage network, the configuration switches and the circuit breaker are very advantageously disconnected, as a result of which the intermediate voltage circuits can be switched in a very simple manner so that there is no direct connection between these intermediate voltage circuits.

In addition, in the case of connecting to the DC voltage network, the intermediate voltage circuits are switched in such a way that there is a direct connection between the intermediate voltage circuits so that it is extremely easy to connect the intermediate voltage circuits in series or in parallel, depending on the respective requirements.

This eliminates the very complex way of connecting the converter circuit, and in particular the complex arrangement of a large number of switches.

Moreover, due to the small number of switches, extremely simple and flexible connection to a wide variety of charging networks can be achieved without the use of additional converter circuit components which would have to be wired or disconnected, for example in the event of a change in the charging network.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail by way of examples of specific embodiments thereof, the description of which will be given with reference to the accompanying drawings, in which:

Fig. 1 shows a diagram of an embodiment of a converter circuit for connection to an electrical charging network; and FIG. 2 shows a flow chart of a method of connecting to an electrical charging network.

The legend to FIG. 2:

step S1 - connecting the converter circuit to an AC power source;

step S1 - supplying the auxiliary converter via a transformer;

step S1a - switching the intermediate DC voltage circuits so that there is no direct connection between the intermediate DC voltage circuits;

step · SI.2b - opening the configuration switches and opening the section switch;

step SI.2c - in the event of failure of the converter circuit elements, disconnection from the electrical load supplied indirectly and / or directly through the damaged converter circuit elements;

step S2 - connecting the converter circuit to a mains voltage source;

step S2.1 - supplying the auxiliary converter via at least one converter section;

step S2.2a - switching the intermediate voltage circuits so that there is a direct connection between the intermediate voltage circuits; .

step S2.2b - if the mains voltage U _g is substantially greater than the nominal voltage U _diN , the opening of the configuration switches and the circuit breaker connection;

step S2.2c - in case the mains voltage U _g has a magnitude in the range of the nominal voltage U _{d / N} , the configuration switches are connected and the circuit breaker is opened;

step S2.2d - in the event of a failure of the converter circuit elements, disconnecting the electrical load supplied indirectly and / or directly through the damaged converter circuit elements.

Examples

In FIG. 1 shows an embodiment of a converter circuit for connection to an electrical charging network. In FIG. 2 is a flow diagram of a method of connecting to an electric charging network according to the present invention;

As shown in FIG. 1, the converter circuit comprises at least one set of 5 converter sections consisting of a first converter section 5.1 and a second converter section 5.2. Each converter section 5.1 and 5.2 is connected via its AC connection to a respective winding of the transformer 7, which can be connected to the AC mains voltage source 2.

If the converter circuit is connected to power supply 2 <

the AC mains voltage is a transformer 11 connected to the mains AC power supply 2 via a switch

4. AC power.

The first transducer section 5.1 is connected on the equal voltage side to the first terminal 9.11 and to the second terminal 9.12 of the first intermediate voltage circuit 14.1. In addition, the second transducer section 5.2 is connected on the DC voltage side to the first terminal 9.21 and to the second terminal 9.22 of the second intermediate voltage circuit 14.2.

In accordance with FIG. 1, both the first intermediate voltage circuit 14.1 and the second intermediate voltage circuit 14.2 are each provided with an intermediate circuit capacitor 6 which forms an energy storage device or accumulator.

In addition, other elements of the intermediate voltage intermediate circuit, such as a discharge device and / or filter elements for reducing or eliminating the harmonic components of the intermediate circuit voltage are usually provided, depending on the requirements imposed on the converter circuit, but which are not shown for clarity and clarity.

J

In addition, the mains voltage supply 1 may be connected to one of the intermediate voltage circuits 14.1 and 14.2, and the converter circuit may be connected to this mains voltage source X by means of the mains voltage switch 3.

_f I. ·

As shown in FIG. 1, in accordance with the present invention there are respective configuration switches

10.1 and 10.2 arranged between the first connection 9.11 of the first intermediate voltage circuit 14.1 and the first connection 9.21 of the second intermediate voltage circuit 14.2, and also between the second connection 9.12 of the first intermediate voltage circuit 14.1 and the second connection 9.22 of the second intermediate voltage circuit 14.2.

In addition, in accordance with the present invention, a circuit breaker 11 is arranged between the second connection 9.12 of the first intermediate voltage circuit 14.1 and the first connection 9.21 of the second intermediate voltage circuit 14.2.

The configuration switches 10.1 and 10.2 and the section switch 11 are preferably designed as mechanical or electronic switches. As a result of the two configuration switches 10.1 and 10.2 and the circuit breaker 11, the converter circuit is designed with a minimum of maintenance-intensive components, and is also designed in a very simple and space-saving manner.

As shown in FIG. 2, and in accordance with the present invention, in the case of the aforementioned connection of the converter circuit to the AC power source 2 (step S1), the two intermediate circuits 14.1 and 14.2 of the uniform voltage circuit 5 are connected in such a way that a direct connection between the intermediate voltage circuits 14.1 and 14.2 (step S1.2a).

To this end, the configuration switches 10.1 and 10.2 and the circuit breaker 11 are open (step S1.2b), which results in a simple connection to the corresponding AC grid.

In addition, the at least one load transducer 12 is connected between the first connection 9.11 and 9.21 and the second connection 9.12 and 9.22 of the associated intermediate voltage circuit 14.1 and 14.2. This makes it possible to ensure a balanced supply of the electrical load 13, in particular of the three-phase partial winding of the rotating electric machine connected to the load transducer 12, without complicated adaptations or arrangement of the converter circuit and its adaptation to the electrical load 13.

In addition, on the transformer 7, according to FIG. 1, at least one winding, to which in each case at least one auxiliary converter 8 is connected, which, for example, supplies the air-conditioning system and the electric rail vehicle fan, and which in the case of connecting the converter circuit to the AC mains voltage source 7 (step S1) supplied by this source 2 through a transformer 7 (step S1.1).

As a result, it is not necessary to advantageously use an additional transformer to power the auxiliary converter 8.

In accordance with FIG. 2, in the case of the above-mentioned connection of the converter circuit to the mains voltage source 1 (cross-section S2), the two intermediate circuits 14.1, 14.2 of the equal voltage system of the converter section 5 are connected according to the invention in such a direct connection between the intermediate circuits 14.1 uniform voltage (step S2.2a).

In the case where the mains voltage U _{g is} significantly greater than the nominal voltage U _{g / N of the} intermediate circuit for the intermediate voltage circuits 14.1 and 14.2, the configuration switches 10.1 and 10.2 are switched off for this purpose (step

S2.2b), wherein the on / off switch 11 is turned on (step S2.2b), whereby a uniformly simple voltage connection is made to the corresponding network by connecting two intermediate voltage circuits 14.1 and 14.2 in series.

Preferably, the two intermediate voltage circuits 14.1 and 14.2 are connected in series when the mains voltage U _{g is} twice greater than the nominal voltage U _g , _{N of the} intermediate circuit.

In addition, each load transducer 12 connected between the first connection 9.11 and 9.21 and the second connection 9.12 and 9.22 of the associated intermediate voltage circuit 14.1 and 14.2 is similarly connected in series due to the two intermediate voltage circuits 14.1 and 14.2 being connected in series.

Due to the connection in series of two intermediate voltage circuits 14.1 and 14.2 and the respective converter sections 5.1 and 5.2 and the load transducers 12 connected thereto, the intermediate circuit voltage of the respective intermediate circuit capacitor 6 is divided according to the values of the associated intermediate circuit capacitor 6. .

A particularly advantageous result is that, especially in the case where the mains voltage U _{g is} greater than or equal to 3kV, rectifiers with the usual permissible value of the opposite voltage can be used, both in the load transducers 12 and in the converter sections. 5.1 and 5.2, since correspondingly distributed voltage values of the intermediate circuit are present as in the load transducers 12 as well as in the transducer sections 5.1 and 5.2.

In accordance with the present invention, further, in the case where the mains voltage U _g is equal to the rated voltage U _g , N, of the intermediate circuit at the intermediate voltage circuits 14.1 and 14.2, the configuration switches 10.1 and 10.2 are connected (step S2.2c). wherein the section switch 11 is open (step S2.2c), whereby a very simple connection to a corresponding DC voltage network is achieved by connecting two intermediate voltage circuits 14.1 and 14.2 in parallel.

In addition, each load transducer 14.1, and between the first connections 9.11 and 9.21 and the second and 9.22 associated intermediate DC voltage circuits, is similarly connected in parallel connection of both DC voltages.

14.2, connected by connection 9.12

14.1 and 14.2 in parallel due to the intermediate circuits 14.1 and 14.2

In accordance with the illustration of the converter voltage (step to the DC connection transformer

S2) connected via at least one power source to the converter 8, (step S2.1)

7, converter section 5.1 and 5.2.

This power supply is preferably operated by means of at least one winding of the transformer 7, as a result of which the auxiliary converter 8 is indirectly connected to the at least one converter section 5.1 and 5.2.

As a result, the auxiliary transducer 8 is electromagnetically coupled to at least one transducer section 5: 1 and 5.2 by winding the transformer 2 · 1.

As in the case of connecting the transducer circuit to the source 2 AC mains voltage then an additional transformer to power the auxiliary converter 2 and other assemblies, such as a converter that converts mains DC voltage U _g source 2 mains uniform voltage and supplies said additional transformer is not needed.

In addition, in accordance with FIG. 1, the load transducer 12 supplies an electrical load 13 embodied as a three-phase partial winding of a rotating electric machine. If there is a failure in the converter circuit, especially in the elements of the converter circuit, such as in the converter section 5.1 and 5.2. in the intermediate circuit 14.1 and 14.2 or in the load transducer 12, then the electrical load 13 supplied directly and / or indirectly through the damaged circuit elements is disconnected in accordance with the present invention.

This disconnection is carried out in accordance with FIG. 2 if the above fault occurs in the case of connecting the converter circuit to the AC power supply 2 (step SI.2c) or in the case of connecting the converter circuit to the power supply 2. DC voltage, if the line voltage U _{g has a} magnitude of the nominal voltage Ud, N of the intermediate circuit (step S2.2c).

To disconnect the electrical load 23, which is configured as a three-phase partial winding of a rotating electric machine, the three-phase disconnecting switch 15 is arranged between the load transducers 12 and the three-phase partial winding in accordance with FIG. First

If the aforementioned failure of circuit elements that indirectly and / or directly feed the electrical load 13 occurs, then the electrical load 13 is disconnected by switching off the three-phase trip switch 15.

If the converter circuit is used mainly in the rail vehicle, after disconnecting the triphasic partial winding of the rotating electric machine, used for example as a drive motor, the rail vehicle can still move under its own power, since the further partial winding of the rotating electric machine is still supplied by undamaged elements. converter circuit. Moreover, said disconnection can advantageously prevent the failure to propagate to undamaged circuit components very successfully.

In conclusion, the converter circuit according to the present invention is a cost-effective solution, since a minimum number of components, especially switches, is used, as a result of which complex and demanding switch maintenance work can be minimized as well as a very simple activation switches.

Furthermore, the method according to the invention allows simple and flexible connection to a wide range of charging networks, in particular to DC voltage networks having different voltage values, and AC voltage networks having variable voltage and frequency values, without using additional converter circuit components which would have to be connected or disconnected, for example, when switching to a charging network.

other ++ 1-2ΧΗΟΛ

Claims (16)

Patent claims A converter circuit for connection to an electric charging X network having at least one converter section assembly (5) comprising a first converter section (5.1) and a second converter section (5.2), wherein each converter section (5.1, 5.2) is connected to the AC voltage side to the respective winding of the transformer (7), which can be connected to the AC power supply (2) and the first transducer section (5.1) is connected on the DC voltage side to the first and second connections (9.11, 9.12). A first intermediate voltage circuit (14.1), the second converter section (5.2) being connected on the equal voltage side to the first and second connections (9.21,9.22) of the second intermediate voltage circuit (14.2), one of the two intermediate circuits (14.1, 14.2) ) the DC voltage can be connected to the mains voltage supply (1), characterized in that the respective configuration switch (10.1, 10.2) is arranged between the first connection (9.11) of the first intermediate voltage circuit (14.1) and the first connection (9.21) ). a second intermediate voltage circuit (14.2), and between the second connection (9.12) of the first intermediate voltage circuit (14.1) and the second connection (9.22) of the second intermediate voltage circuit (14.2), wherein: the section switch (11) is arranged between the second "terminal" (9.12) of the first intermediate voltage circuit (14.1) and the first connection (9.21) of the second intermediate circuit (9.21) of the second intermediate voltage circuit (14.2). Converter circuit according to Claim 1, characterized in that the switches (10.1, 10.2) are designed as mechanical or electronic switches. A converter circuit according to claim 1, characterized in that the section switch (11) is designed as a mechanical or electronic switch. The converter circuit according to claim 1, characterized in that at least one load converter (12) is connected between the first and second connections (9.11, 9.12, 9.21, 9.22) of the associated intermediate voltage circuits (14.1, 14.2). The converter circuit according to claim 4, characterized in that the load converter (12) is connected to an electrical load (13) on the AC voltage side. The converter circuit according to claim 5, characterized in that the electrical load (13) is a three-phase partial winding of the rotating electric machine. The converter circuit according to claim 6, characterized in that the triphasic disconnecting switch (15) is arranged between the triphasic partial winding and the load converter (12). A converter circuit according to claim 1, characterized in that at least one auxiliary converter (8) is provided. connected indirectly to at least one converter section (5.1, 5.2). The converter circuit according to claim 8, wherein the auxiliary converter (8) is connected, in particular electromagnetically, to the at least one converter section (5.1, 5.2) by means of at least one winding of the transformer (7). 10. A method of connecting to an electrical charging network, comprising the following steps: Step S1 - connecting the AC power supply (2) via the AC power switch (4) of the transformer (7) and the converter circuit, wherein at least a first section of one assembly (5) of the converter (5.2) is connected to and the first converter. Each side of the converter circuit comprises converter sections consisting of (5.1) and the second converter converter section (5.1, 5.2) is an AC voltage transformer (7) the section (5.1) is connected on the equal voltage side to the first and second connections (9.11, 9.12). ) of a first intermediate voltage circuit (14.1), wherein the second converter section (5.2) is connected to the equal voltage side to the first and second connections (9.21, 9.22) of the second intermediate voltage circuit (14.2), or step S2 - connecting one of the two intermediate circuits (14.1, 14.2) of the uniform voltage of the assembly (5) of the converter sections to the source (1) mains voltage by means of mains voltage switch (3), characterized in that it comprises the following further steps: step SI.2a - switching the intermediate circuits (14.1, 14.2) of the uniform voltage of the converter section assembly (5) in the case of connecting the converter circuit to the AC power supply (2) in such a way that there is no direct connection between the intermediate DC voltage circuitry (14.1, 14.2), since step S2.2a - switching the intermediate voltage circuitry (14.1, 14.2) of the converter section assembly (5) when the converter circuit is connected to the mains voltage supply (1) in such a manner (step S2) that there is a direct connection between the intermediate voltage circuits (14.1, 14.2). The pole method of claim 10, comprising the following additional steps: > steps SI, SI.2a - in the case of connecting the converter circuit to the AC power supply (2), step SI.2b to open the configuration switches 10.2), arranged between the first connection (9.11) (10.1, 'first'). the intermediate voltage circuit (14.1) and the first connection (9.21) of the second intermediate voltage circuit (14.2) and between the second connection (9.12) of the first connection (9.22) of the second intermediate circuit (14.2) of the intermediate circuit (14.1) and a step S1b of disconnecting a section switch arranged between the second connection of the first intermediate voltage circuit (14.1) and the first connection (9.21) of the second intermediate voltage circuit (14.2). 12. The method of claim 10 comprising the following additional steps: the steps S2, S2.2a of the circuit k in the case of the connection of the mains voltage supply (1) and the mains voltage (U _g ) is the intermediate voltage (Ud.ti) intermediate for the intermediate voltage circuits (14.1, 14.2), larger than significantly perimeter step S2 .2b - disconnect configuration switches (10.1, 10.2), arranged between first connection (9.11) first intermediate circuit (14.1) uniform voltage and the first connection (9.21) second intermediate 'circuit (14.2) uniform ' voltage and between second connection (9.12) first medziľahlého- circuit (14.1) uniform voltage a second Connect with (9.22) second intermediate circuit (14.2) evenly voltage and a step S2.2b of switching the section switch (11) arranged between the second connection (9.12), the first connection (9.21) of the second intermediate circuit (14.2) of the intermediate voltage circuit (14.1) and the first equal voltage. Method according to claim 10, characterized in that it comprises the following further steps: steps S2, S2.2a - in case the converter circuit is connected to the mains voltage supply (1) and in case the mains voltage (U _g ) has the size of the rated voltage (Ud, _N ) of the intermediate circuit for the intermediate circuits (14.1, 14.2) , uniform voltage, step S2.2b - switching on configuration switches (10.1, 10.2), arranged between first connection (9.11) first intermediate circuit (14.1) uniform voltage a first connection (9.21) of the other intermediate circuit (14.2) uniform voltage, and between second connection (9.12) first intermediate circuit (14.1) uniform voltage a second connection (9.22) of the other intermediate circuit (14.2) uniform voltage, a a step S2.2c of opening the section switch arranged between the second connection (9.12) of the first intermediate circuit (14.1). of a uniform voltage by the first connection (9.21) of the second intermediate voltage circuit (14.2). 14. 10. The method of claim 10 comprising the following additional step: step S1 in the case of connecting the converter circuit to the AC power supply (2), step S1 - supplying the auxiliary converter (8) from the AC power supply (2) by means of a transformer (7). A method according to claim 10, characterized in that it comprises the following further step: step S2 - in the case of connecting the converter circuit to the source (1) of the mains voltage, step S2.1 - supplying the auxiliary converter via at least one converter section (5.1, 5.2). A method according to claim 11 or 12. characterized in that it comprises the following further step: in the event of a failure of the converter circuit elements, steps S1.2c, S2.2d - disconnecting the electrical load (13), fed, indirectly and / or through the damaged elements of the converter circuit.