阅读说明：本技术 变流器、具有变流器的布置和其运行的方法 (Converter, arrangement comprising a converter and method for operating the same ) 是由 马丁·皮舍尔 多米尼克·舒斯特 于 2020-03-17 设计创作，主要内容包括：本发明涉及一种具有子转换器(9)的变流器(2),子转换器具有：用于在输入的电的三相电源系统处连接的子转换器自身的输入三相电源接口(L1’,L2’,L3’),以及形成子转换器自身的输出三相电源系统的子转换器自身的输出三相电源接口(A’、B’,C’),和用于接触子转换器自身的输出三相电源系统的星形接点的子转换器自身的星形接点接口(X)。根据本发明提出,变流器(2)包括至少一个另外的子转换器(9),该子转换器具有子转换器自身的输入三相电源接口(L1’,L2’,L3’)、形成子转换器自身的输出三相电源系统的子转换器自身的输出三相电源接口(A’、B’,C’)和用于接触子转换器自身的输出三相电源系统的星形接点的子转换器自身的星形接点接口(Y),子转换器(9)关于其子转换器自身的输入三相电源接口(L1’,L2’,L3’)并联连接,并且并联连接的子转换器自身的输入三相电源接口(L1’,L2’,L3’)形成用于在一个或相同的输入的三相电源系统处连接的变流器自身的输入三相电源接口(L1,L2,L3),并且子转换器(9)关于其子转换器自身的输出三相电源接口(A’、B’,C’)并联连接,其中,子转换器(9)的每个子转换器自身的输入三相电源接口分别具有一个转换器模块(10),并且转换器模块(10)分别具有两个或者更多输出侧的电串联连接的子模块(13)、一个变压器(17)。(The invention relates to a converter (2) having a sub-converter (9), comprising: an input three-phase power interface (L1 ', L2', L3 ') of the sub-converter itself for connection at an input electrical three-phase power system, and an output three-phase power interface (a', B ', C') of the sub-converter itself forming an output three-phase power system of the sub-converter itself, and a star-contact interface (X) of the sub-converter itself for contacting star-contacts of the output three-phase power system of the sub-converter itself. According to the invention, the converter (2) comprises at least one further sub-converter (9) having its own input three-phase power supply interface (L1 ', L2 ', L3 '), its own output three-phase power supply interface (A ', B ', C ') forming the output three-phase power supply system of the sub-converter itself and its own star point interface (Y) for contacting the star points of the output three-phase power supply system of the sub-converter itself, the sub-converter (9) being connected in parallel with respect to its own input three-phase power supply interface (L1 ', L2 ', L3 '), and the parallel-connected sub-converter's own input three-phase power supply interface (L1 ', L2 ', L3 ') forming an own input three-phase power supply interface (L1, l2, L3), and the sub-converters (9) are connected in parallel with respect to their own output three-phase power interfaces (a ', B ', C '), wherein each of the sub-converters (9) own input three-phase power interfaces has one converter module (10), respectively, and the converter modules (10) have two or more output-side sub-modules (13), one transformer (17), respectively, which are electrically connected in series.)

1. A current transformer (2) with a sub-converter (9) having:

-an input three-phase power interface (L1 ', L2 ', L3 ') for the subconverter itself connected at the input electrical three-phase power system and

-the output three-phase power interface (a ', B ', C ') of the sub-converter itself forming the output three-phase power system of the sub-converter itself, and

a star-contact interface (X) of the sub-converter itself for contacting the star-contacts of the output three-phase power supply system of the sub-converter itself,

it is characterized in that the preparation method is characterized in that,

-the converter (2) comprises at least one further sub-converter (9) having: said input three-phase power interface (L1 ', L2', L3 ') of the sub-converter itself, said output three-phase power interface (A', B ', C') of the sub-converter itself forming the output three-phase power system of the sub-converter itself and the star-contact interface (Y) of the sub-converter itself for contacting the star-contacts of the output three-phase power system of the sub-converter itself,

-the sub-converters (9) are connected in parallel with respect to the input three-phase power interfaces (L1 ', L2', L3 ') of their sub-converters themselves, and the input three-phase power interfaces (L1', L2 ', L3') of their parallel connected sub-converters themselves form the input three-phase power interfaces (L1, L2, L3) for the converters themselves connected at the same input three-phase power system, and

-the sub-converters (9) are connected in parallel with respect to the output three-phase power interface (A ', B ', C ') of their sub-converters themselves,

-wherein each of the sub-converters (9) and the further sub-converters (9) has its own input three-phase power interface with one converter module (10) respectively,

-wherein the converter modules (10) each have two or more output-side sub-modules (13) which are electrically connected in series, a transformer (17) having a primary winding (17a) and each sub-module (13) has a secondary winding (17b),

-wherein each of the submodules (13) is individually connected on the input side with the secondary winding of the transformer,

-wherein the primary windings of the transformers are arranged in a star circuit and connected with the input three-phase power interface (L1 ', L2 ', L3 ') of the sub-converter itself, respectively.

2. Converter (2) according to claim 1, characterized in that the star point interfaces (X, Y) of the sub-converters themselves are capable of realizing the output of a direct voltage or a single-phase alternating voltage.

3. The converter (2) according to any of the preceding claims, characterized in that each of the converter modules (10) has a module-side input three-phase power interface (Lm), a module-side neutral line interface (Nm), a module-side output three-phase power interface (Am) and a module-side star point interface (Sm),

-wherein the module-side neutral interfaces of the converter modules (10) are connected to each other and form the neutral interfaces of the sub-converters themselves of the respective sub-converters (9),

-wherein the module-side star-contact interfaces of the converter modules (10) are connected to each other and form the star-contact interfaces of the sub-converters themselves of the respective sub-converter (9),

-wherein the module-side input three-phase power interfaces each form one of the input three-phase power interfaces (L1 ', L2 ', L3 ') of the respective sub-converter (9) itself, and

-wherein the module-side output three-phase power interfaces each form one of the output three-phase power interfaces (a ', B ', C ') of the respective sub-converter (9) itself.

4. The converter (2) according to any of claims 1 to 3,

-one of the interfaces of the primary winding (17a) of the transformer (17) forms a module-side input three-phase power interface, and

-the other interface of the primary winding (17a) of the transformer forms a module-side neutral interface.

5. The converter (2) according to any of claims 1 to 4, characterized in that the sub-modules (13) have a rectifier module (16) connected with the secondary windings of the transformer associated with the sub-modules (13), a capacitor module (15) downstream of the rectifier module (16) and an inverter module (14) downstream of the capacitor module (15), respectively.

6. The converter (2) according to any of the preceding claims 1 to 5, characterized in that the electrical series circuit of the sub-modules (13) is based on a cascade interconnection of the alternating voltage interfaces (AC1, AC2) of the inverter modules (14).

7. A converter arrangement, characterized in that it is equipped with at least one converter (2) according to any of the preceding claims.

8. The current transformer arrangement of claim 7,

-the output three-phase power interfaces (A ', B ', C ') of the sub-converters themselves connected in parallel form the output three-phase power interfaces (A, B, C) of the converters themselves, and

-a primary circuit side of a three-to-two phase single phase transformer (24) is connected at the output three phase power interface (a, B, C) of the converter itself.

9. The current transformer arrangement according to the previous claim 7 or 8,

-the output three-phase power interfaces (a ', B ', C ') of the sub-converters themselves connected in parallel form the output three-phase power interfaces (a, B, C) of the converters themselves, and

-the output three-phase power interface (a, B, C) of the converter itself is connected at the primary circuit side of the transformer (24), which transformer is suitable for outputting two alternating voltages with a phase difference of 90 degrees on the secondary circuit side of the transformer.

10. The converter arrangement according to any of the preceding claims 7 to 9, characterized in that an electrical storage (23) is connected between the star-contact interface (X) of the sub-converter itself of a sub-converter (9) and the star-contact interface (Y) of the sub-converter itself of at least one further sub-converter (9).

11. The converter arrangement according to any of the preceding claims 7 to 10, characterized in that an electrical consumer (23) is connected between the star-contact interface (X) of the sub-converter itself of a sub-converter (9) and the star-contact interface (Y) of the sub-converter itself of at least one further sub-converter (9).

12. The current transformer arrangement according to any one of the preceding claims 7 to 11,

-the converter arrangement comprises a generator, in particular an asynchronous machine (22), which provides at least two generator-side output three-phase power supply systems,

one of the output three-phase power supply systems on the generator side is connected to the input three-phase power supply connections (L1, L2, L3) of the converter itself, and

the other generator-side output three-phase power supply system is connected to the output three-phase power supply connections (a, B, C) of the converter itself.

13. The current transformer arrangement according to any one of the preceding claims 7 to 12,

the output three-phase power supply interfaces (A ', B ', C ') of the sub-converters themselves connected in parallel form the output three-phase power supply interfaces (A, B, C) of the internal converters themselves, and,

-each converter's own input three-phase power interface (L1, L2, L3) is electrically connected to one of its own output three-phase power interfaces (a, B, C) of the internal converter.

14. A method for operating a converter (2) according to one of the preceding claims,

-inputting three-phase currents in the converter (2) with one of the input three-phase currents connected at the input three-phase power interface (L1, L2, L3) of the converter itself, and,

-controlling the sub-modules (13) in the sub-converters (9) of the converter (2) such that the output three-phase currents are available at the output three-phase power interfaces (a ', B ', C ') of the sub-converters themselves connected in parallel and/or that a direct voltage or a single-phase alternating voltage is generated between the star-point interfaces (X, Y) of the sub-converters themselves.

Technical Field

The invention relates to a converter, an arrangement having a converter and a method for operating the same.

The invention also relates to a converter with a sub-converter, the sub-converter having: the input three-phase power interface of the sub-converter itself for connection at the input electrical three-phase power system, as well as the output three-phase power interface of the sub-converter itself forming the output three-phase power system of the sub-converter itself, and the star point interface of the sub-converter itself for contacting the star point of the output three-phase power system of the sub-converter itself.

Background

Converters with sub-converters of the described type, and therefore also sub-converters per se, are generally known and are offered and sold, for example, by Siemens AG under the product name sinamic Perfect harmonic GH 180.

Disclosure of Invention

The object of the invention is to further improve a converter of the described type.

The object is achieved according to the invention by a converter having the features according to claim 1. Advantageous embodiments of the converter according to the invention are given in the dependent claims.

It is then proposed according to the invention that the converter comprises at least one further sub-converter having its own input three-phase power supply interface, its own output three-phase power supply interface forming its own output three-phase power supply system and its own star contact interface for contacting the star contacts of its own output three-phase power supply system, the sub-converters being connected in parallel with respect to their own input three-phase power supply interface and the parallel-connected sub-converters 'own input three-phase power supply interfaces forming the converter's own input three-phase power supply interface for connection at one and the same input three-phase power supply system and the sub-converters being connected in parallel with respect to their own output three-phase power supply interface.

The converter according to the invention has the main advantage that it can optionally generate a dc voltage or an ac voltage of any frequency and can output a corresponding dc current or ac current when the converter or the sub-converter is driven or controlled appropriately at the star point interface.

A further advantage of the converter according to the invention is that, in the case of corresponding external wiring of the output three-phase power supply connections of the parallel-connected partial converters themselves, it is additionally also possible to output three-phase currents on the output side.

The converter according to the invention is also advantageous in that the sub-converters can have no common intermediate circuit dc voltage.

It is advantageous if the input three-phase power interface of each of the one and the further sub-converters has a converter module, respectively, of its own.

Preferably, each converter module has a module-side input three-phase power supply interface, a module-side neutral line interface, a module-side output three-phase power supply interface and a module-side star point interface.

The module-side neutral connections of the converter modules are preferably connected to one another and preferably form the neutral connections of the partial converters of the respective partial converters themselves.

Preferably, the module-side star point interfaces of the converter modules are connected to each other and form the star point interfaces of the sub-converters themselves of the respective sub-converters.

The module-side input three-phase power supply interfaces preferably each form one of the input three-phase power supply interfaces of the respective sub-converter of the sub-converter itself.

Preferably, the module-side output three-phase power supply interfaces each form one of the output three-phase power supply interfaces of the respective sub-converter itself.

It is also advantageous if the converter modules each have two or more sub-modules connected electrically in series, a transformer having a primary winding and each sub-module having a secondary winding.

The current separation between the three-phase power supply interface of the sub-converter itself and the star-point interface of the sub-converter itself can also be achieved by means of a transformer. The three-phase power supply connections of the partial converters themselves and the output three-phase power supply connections of the partial converters themselves are also galvanically separated from one another, so that different reference potentials can be freely preset for the two connection systems. The reference potential for the output three-phase power supply interface of the partial converters themselves can be preset, for example, via the star point interface of one or both partial converters themselves.

Preferably, each submodule is connected on the input side individually to one of the secondary windings of the transformer.

Preferably, one of the interfaces of the primary winding of the transformer forms the input three-phase power interface on the module side, and preferably the other interface of the primary winding of the transformer forms the neutral interface on the module side.

Preferably, the submodules each have a rectifier module, a capacitor module downstream of the rectifier module and an inverter module downstream of the capacitor module, wherein the rectifier module is connected to the secondary winding of the transformer associated with the submodule.

Preferably, the electrical series circuit of the submodules is based on a cascade interconnection of the ac voltage interfaces of the inverter modules.

The invention also relates to a converter arrangement with at least one converter as described above.

It is advantageous if the output three-phase power supply connections of the sub-converters themselves connected in parallel in the transformer arrangement form accessible output three-phase power supply connections of the converter itself from the outside (external).

Preferably, the primary circuit side of a three-to-two phase single phase transformer is connected at the output three phase power interface of the transformer itself.

It is also advantageous if (alternatively or additionally) the output three-phase power interface of the transformer itself is connected at the primary circuit side of the transformer, for which the transformer is adapted to output the two alternating voltages with a phase difference of 90 degrees on its secondary circuit side.

Preferably, the electrical storage device and/or the electrical consumer, in particular the electrical resistor, is connected between the star point interface of the partial converter of the one partial converter and the star point interface of the partial converter of the at least one further partial converter.

It is also advantageous if the converter arrangement comprises a generator, in particular an asynchronous machine, which provides at least two generator-side output three-phase power supply systems, one of the generator-side output three-phase power supply systems being connected to the input three-phase power supply interface of the converter itself and the other generator-side output three-phase power supply system being connected to the output three-phase power supply interface of the converter itself.

In an alternative embodiment, which is also considered to be advantageous, it is proposed that the output three-phase power supply connections of the parallel-connected partial converters form the output three-phase power supply connections of the internal converters themselves, and that the input three-phase power supply connection of each converter itself is electrically connected to one of the output three-phase power supply connections of the internal converter itself.

The invention also relates to a method for operating a converter as described above. According to the invention, three-phase currents are input into the converter by means of one of the three-phase input currents connected at the three-phase input power connections of the converter itself, and the submodules in the sub-converters of the converter are controlled in such a way that the three-phase output current is available at the three-phase output power connections of the sub-converters connected in parallel and/or a direct voltage or a single-phase alternating voltage is generated between the star-point connections of the sub-converters themselves.

Drawings

The invention is further explained below with reference to examples. Here, it is exemplarily shown that:

fig. 1 shows an exemplary embodiment of a converter arrangement according to the present invention, with an exemplary embodiment of a converter (umichter) according to the present invention;

fig. 2 shows the current transformer according to fig. 1 in detail;

FIG. 3 illustrates an embodiment of a sub-converter;

FIG. 4 illustrates an embodiment of a converter module;

FIG. 5 illustrates an embodiment of a sub-module;

fig. 6 shows an embodiment of an inverter module;

fig. 7 shows another embodiment of an inverter module;

FIG. 8 illustrates an embodiment of a capacitor module;

FIG. 9 illustrates an embodiment of a rectifier module;

fig. 10 shows a further embodiment of a current transformer arrangement according to the invention with an embodiment of a current transformer according to the invention;

fig. 11 shows a third embodiment of a current transformer arrangement according to the invention with an embodiment of a current transformer according to the invention; and

fig. 12 shows a further exemplary embodiment of a current transformer according to the present invention.

In the drawings, the same reference numerals are used for the same or similar parts for clarity.

Detailed Description

Fig. 1 shows an arrangement with an exemplary embodiment of a converter 2 according to the present invention, which is connected to an electrical supply network 1 via a transformer 6. The current through the converter 2 is measured by means of a current measuring device 3 and the connection voltage at the converter 2 is measured by means of a voltage measuring device 4. The measured values are processed by a converter control unit 5 which controls and controls the converter 2. For example, a single-phase load 7 and/or a three-phase load 8 can be connected to the converter 2. Preferably, the converter 2 is a multilevel converter.

Fig. 2 shows an exemplary embodiment of the converter 2 according to fig. 1 in detail. The current transformer 2 comprises a first sub-converter and a second sub-converter. Preferably, the two sub-converters identified in the figure with reference number 9 are of identical construction and respectively comprise an input three-phase power interface L1 ', L2', L3 'of the sub-converter itself for connection at the fed electrical three-phase power system, an output three-phase power interface a', B ', C' of the sub-converter itself forming the output three-phase power system of the sub-converter itself, and a star point interface X or Y of the sub-converter itself for contacting the star point of the output three-phase power system of the sub-converter itself.

The two sub-converters 9 are connected in parallel with respect to their own input three-phase power interfaces L1 ', L2 ', L3 '. The input three-phase power connections L1 ', L2 ', L3 ' of the parallel-connected sub-converters themselves form the input three-phase power connections L1, L2, L3 for the converters themselves connected at one and the same input three-phase power system.

In addition to this, the sub-converters 9 are connected in parallel with respect to their own output three-phase power interfaces a ', B ', C '. According to fig. 2, in an embodiment variant, the output three-phase power supply interfaces a ', B ', C ' of the sub-converters themselves form the output three-phase power supply interfaces A, B, C of the converters themselves, which are routed to and accessible from the outside. Thus, according to fig. 2, the converter's own output three-phase power interface A, B, C can also be referred to as the converter's own output three-phase power interface A, B, C, which is externally accessible.

According to fig. 1, the star point interfaces X and Y of the partial converters themselves can be controlled by the converter control unit 5 to output a direct voltage or a single-phase alternating voltage as a function of the control of the partial converters 9. The frequency of the single-phase ac voltage is dependent on the actuation of the converter 2 by the converter actuation unit 5 and can be adjusted from the outside in a wide range.

The three-phase voltage output at the output three-phase power supply connection A, B, C of the converter itself is accordingly suitable, the frequency of which is likewise dependent on the actuation of the converter by the converter actuation unit 5 and can therefore likewise be set arbitrarily from the outside in a wide range. The frequency of the three-phase voltage can be different from the frequency of the single-phase alternating voltage at the star point interfaces X and Y and from the frequency of the input three-phase voltage of the input three-phase power system at the input three-phase power interfaces L1, L2, L3 of the converter itself.

Fig. 3 shows an embodiment of the sub-converter 9 according to fig. 2. Each of the sub-converters 9 has its own input three-phase power interface L1 ', L2 ', L3 ' with a converter module 10, respectively. Each converter module 10 comprises a module-side input three-phase power interface Lm, a module-side zero line interface Nm, a module-side output three-phase power interface Am and a module-side star point interface Sm, respectively. The module-side neutral interfaces Nm of the converter modules 10 are connected to one another and form the neutral interfaces N of the sub-converters themselves of the sub-converter 9.

The module-side star point interfaces Sm of the converter modules 10 are connected to one another and form the star point interface X or Y of the sub-converter itself of the sub-converter 9. The module-side input three-phase power interface Lm forms the input three-phase power interfaces L1 ', L2 ', L3 ' of the sub-converters themselves of the sub-converter 9, respectively. The module-side output three-phase power supply interface Am forms one of the output three-phase power supply interfaces a ', B ', C ' of the sub-converters of the sub-converter 9, respectively.

Fig. 4 shows an embodiment of the converter module 10 according to fig. 3. The converter module 10 has two or more sub-modules 13 electrically connected in series, a transformer 17 having a primary winding 17a and one secondary winding 17b per sub-module 13. Each submodule 13 is connected on the input side individually to a secondary winding 17b of the transformer 17.

One of the interfaces of the primary winding 17a of the transformer 17 forms the input three-phase power interface Lm of the module side and the other interface of the primary winding 17a forms the neutral line interface Nm of the module side.

In addition, a coupling inductance 12 and a current measuring device 11 are connected in series with the submodule 13, which current measuring device measures the current i _ conv through the converter module 10 and transmits the current measured value, preferably to the converter control unit 5 according to fig. 1.

Fig. 5 shows an embodiment of the submodule 13 according to fig. 4.

Submodule 13 has a rectifier module 16, which is connected to a secondary winding 17b of transformer 17 associated with submodule 13 and is supplied with power by secondary winding 17b, for which interfaces Lsm and Nsm of submodule 13 are used.

In addition to this, the submodule 13 has a capacitor module 15 downstream of the rectifier module 16 (as seen in the energy flow direction or energy input direction E) and an inverter module 14 downstream of the capacitor module 15 (as seen in the energy flow direction E). The electrical series circuit of the submodule 13 shown in fig. 4 is based on a cascade interconnection of the alternating voltage interfaces AC1 and AC2 of the inverter module 14. The internally located interfaces of the rectifier module 16, the capacitor module 15 and the inverter module 14 are shown in fig. 5 with reference numerals DC7 and DC8 (for the rectifier module 16), DC3 and DC4 or DC5 and DC6 (for the capacitor module 15) and DC1 and DC2 (for the inverter module 14).

Fig. 6 shows an embodiment of the inverter module 14 according to fig. 5. The inverter module 14 is formed by an H-bridge module consisting of four semiconductor switches 18. Suitable semiconductor switches 18 are, for example, Insulated Gate Bipolar Transistors (IGBTs), Integrated Gate Commutated Thyristors (IGCTs), electron Injection Enhanced Gate Transistors (IEGTs) or Metal Oxide Semiconductor Field Effect Transistors (MOSFETs).

Fig. 7 shows a further exemplary embodiment of the inverter module 14 according to fig. 5. The inverter module 14 is formed by a half-bridge module consisting of two semiconductor switches 18. Suitable semiconductor switches 18 are for example IGBTs, IGCTs, IEGTs or MOSFETs.

Fig. 8 shows an embodiment of the capacitor module 15 according to fig. 5. The capacitor module 15 is composed of a capacitor 20, which buffers the intermediate circuit voltage Uz, and a voltage measuring device 19, which is connected in parallel, measures the intermediate circuit voltage Uz and transmits the voltage measured values to the converter control unit 5, preferably according to fig. 1.

Fig. 9 shows an embodiment of the rectifier module 16 according to fig. 5. The rectifier module 16 comprises four diodes 21 for rectifying a single-phase alternating voltage. Alternatively, the rectifier module can also use a three-phase bridge rectifier.

Fig. 10 shows a further exemplary embodiment of the arrangement according to fig. 2 with a current transformer 2. The converter 2 serves to couple the doubly-fed asynchronous machine 22 to the electrical supply grid 1.

The asynchronous machine 22 has a first ac winding connected to the converter 2 at its own input three-phase power interface L1, L2, L3 and a second ac winding connected in common (or in parallel) with the converter's own output three-phase power interface A, B, C at the network 1. Preferably, the asynchronous machine 22 generates a three-phase voltage at the first ac winding having a frequency of, for example, 5 to 10Hz, and the second ac winding of the asynchronous machine 22 is supplied with the three-phase voltage of the supply network having a frequency of, for example, 50 Hz.

The converter 2 is connected at its star point interfaces X and Y to a resistor and/or electrical storage 23, which can be used to store and/or store generator energy and thus to protect the electrical supply grid 1 in the event of a network fault.

Fig. 11 shows a third exemplary embodiment of the arrangement according to fig. 2 with a current transformer 2. The converter 2 is supplied with energy at its own input three-phase power supply connections L1, L2, L3, to which an electrical three-phase network, not shown in detail, is connected.

The converter 2 is used, for example, for supplying the power of the rail network of electricity and is connected for this purpose to a three-phase to two-phase single-phase transformer 24 with its own output three-phase power supply interface A, B, C. Preferably, the three-to-two phase single phase transformer 24 is a Scott (Scott) or LeBlanc transformer.

The three-phase to two-phase single-phase transformer 24 has, on the output side, interfaces U1 and Y1 for outputting a first alternating voltage and U2 and Y2 for outputting a second alternating voltage. Preferably, the first and second alternating voltages have the same frequency, e.g. 162/3 Hz, but are preferably 90 degrees out of phase with each other.

The converter 2 is connected at its star point interfaces X and Y to a resistor and/or electrical storage 23 which can be used as a rail network for receiving and/or storing generator energy and thus for protecting the rail side or the electricity in the event of a network fault.

Fig. 12 shows a further embodiment of a current transformer 2 according to the invention in further detail. The converter 2 according to fig. 12 comprises a first and a second sub-converter and the corresponding converter 2 according to fig. 2 differs in that the output three-phase power connections a ', B', C 'of the sub-converters connected in parallel form the output three-phase power connection A, B, C of the converter itself inside, which is connected to the input three-phase power connections L1, L2, L3 of the converter itself, i.e. the input three-phase power connections L1', L2 ', L3' of the sub-converters connected in parallel likewise.

Therefore, the input three-phase power interfaces L1, L2, L3 of the converter itself and the star point interface X, Y of the sub-converter itself, which enable the output of a direct-current voltage or a single-phase alternating-current voltage, are accessible or routable from the outside.

In summary, the present invention relates to a converter having a sub-converter, the sub-converter having: the input three-phase power interface of the sub-converter itself for connection at the input electrical three-phase power system, as well as the output three-phase power interface of the sub-converter itself forming the output three-phase power system of the sub-converter itself, and the star point interface of the sub-converter itself for contacting the star point of the output three-phase power system of the sub-converter itself. According to the invention, the converter comprises at least one further sub-converter, which forms an input three-phase power supply interface of the sub-converter itself, an output three-phase power supply system of the sub-converter itself, and which has a star-contact interface of the sub-converter itself for contacting a star-contact of the sub-converter itself of the output three-phase power supply system, the sub-converters being connected in parallel with respect to their own input three-phase power supply interface, and the parallel-connected input three-phase power supply interfaces of the sub-converters themselves forming an input three-phase power supply interface of the converter itself for connection at one or the same input three-phase power supply system, and the sub-converters being connected in parallel with respect to their own output three-phase power supply interface, wherein the input three-phase power supply interfaces of each sub-converter of the sub-converter itself each have a converter module, and the converter modules each have two or more output-side sub-modules, one transformer, which are electrically connected in series.

The converter 2 can be described as an example in conjunction with fig. 1 to 12, and depending on the wiring, it is possible to implement a three-phase voltage generation and an additional dc or ac voltage generation from the three-phase network on the input side, each with an arbitrary output frequency without a common electrical intermediate circuit.

Although the invention is further explained and described in detail by means of preferred embodiments, the invention is not limited by the disclosed examples and other variants can be derived by the person skilled in the art without departing from the scope of protection of the invention.