Converter arrangement

Patent metadata

Field	Value
Publication number	US-2016172991-A1
Application number	US-201615052534-A
Country	US
Kind code	A1
Filing date	Feb 24, 2016
Priority date	Aug 30, 2013
Publication date	Jun 16, 2016
Grant date	—

Abstract

A converter arrangement comprises first and second modular multilevel converters, Each of the modular multilevel converters comprises two converter branches. Each converter branch comprises a plurality of series-connected converter cells. Each converter cell comprises a cell capacitor and semiconductor switches for connecting and disconnecting the cell capacitor to the converter branch. At least two converter branches of the first modular multilevel converter are connected via first branch connection point and at least two converter branches of the second modular multilevel converter are connected via second branch connection point. The multilevel converters are connected in parallel via a phase connection point for connecting the converter arrangement to a load or a power source, wherein the phase connection point is connected via a first inductance with the first branch connection point and/or via a second inductance with the second branch connection point. At least one of the modular multilevel converters comprises a protection system.

First claim

1 - 15 . (canceled)

16 . A converter arrangement, wherein the converter arrangement comprises:
at least first and second modular multilevel converters; wherein each of the at least first and second modular multilevel converters comprises at least two converter branches; wherein each converter branch comprises a plurality of series-connected converter cells, each converter cell comprising a cell capacitor and semiconductor switches for connecting the cell capacitor to the converter branch; wherein the at least two converter branches of the first modular multilevel converter are connected via a first branch connection point and the at least two converter branches of the second modular multilevel converter are connected via a second branch connection point; wherein the at least first and second multilevel converters are connected in parallel via a phase connection point for connecting the converter arrangement to a load or a power source, wherein the phase connection point is connected via a first inductance with the first branch connection point and/or via a second inductance with the second branch connection point, wherein at least one of the first and second modular multilevel converters comprises a protection system, which comprises: a fault detection device; a mechanical or paraelectronic switch for interconnecting at least two phases at the branch connection point of the associated modular multilevel converter; and a controller adapted for switching converter cells of the associated modular multilevel converter to zero output voltage and for closing the switch, when receiving a fault signal from the fault detection device, wherein the fault detection device comprises a current sensor for sensing an over-current in the at least two phases at the phase connection point; and/or wherein the current sensor is adapted for measuring a current between the phase connection point and the first and/or second inductance before the branch connection point

17 . The converter arrangement of claim 16 , wherein
each of the first and second modular multilevel converters comprises converter branches for at least two phases, and either the converter branches of each phase are connected via an inductance for each phase with a phase connection point for each phase or a pair of two converter branches of the first and the second modular multilevel converter share one or more inductances.

18 . The converter arrangement of claims 16 ,
wherein each of the at least two converter branches of each of the at least first and second modular multilevel converters is connected via a branch inductance with the respective converter branch connection point.

19 . The converter arrangement of claims 17 ,
wherein each of the at least two converter branches of each of the at least first and second modular multilevel converters is connected via a branch inductance with the respective converter branch connection point.

20 . The converter arrangement claim 16 ,
wherein the at least first and second modular multilevel converters comprise a subconverter for converting an AC current into an DC current.

21 . The converter arrangement of claim 16 ,
wherein each of the at least first and second modular multilevel converters is an indirect converter comprising an active rectifier connected via a DC link with an inverter.

22 . The converter arrangement of claim 21 ,
wherein the first modular multilevel converter comprises a first DC link and the second modular multilevel converter comprises a second DC link, which is galvanically separated from the first DC link.

23 . The converter arrangement of claim 21 ,
wherein the at least first and second modular multilevel converters comprise a common DC link.

24 . The converter arrangement of claim 16 wherein the first and second modular multilevel converters are direct converters.

25 . The converter arrangement of claims 17 wherein the first and second modular multilevel converters are direct converters.

26 . The converter arrangement of claim 16 ,
wherein the converter arrangement comprises a transformer and the at least first and second modular multilevel converters are connected via a transformer-side phase connection point with the transformer, such that the at least first and second modular multilevel converters are galvanically connected; wherein the transformer-side phase connection point is connected via a first transformer-side inductance with a first transformer-side branch connection point and via a second transformer-side inductance with a second transformer-side branch connection point.

27 . The converter arrangement of claim 16 ,
wherein the at least first and second modular multilevel converters are galvanically separated on a transformer side; wherein the first modular multilevel converter is connected via a first transformer to a phase connection point and the second modular multilevel converter is connected via a second transformer to the phase connection point; or wherein the first modular multilevel converter is connected to a first secondary winding of a transformer and the second modular multilevel converter is connected to a second secondary winding of the transformer.

28 . The converter arrangement of claim 16 ,
wherein the at least first and second modular multilevel converters are galvanically connected via a load-side phase connection point to a load or a power source; wherein the load-side phase connection point is connected via a first load-side inductance with a first load-side branch connection point and via a second load-side inductance with a second load-side branch connection point.

29 . The converter arrangement of claim 17 ,
wherein the at least first and second modular multilevel converters are galvanically connected via a load-side phase connection point to a load or a power source; wherein the load-side phase connection point is connected via a first load-side inductance with a first load-side branch connection point and via a second load-side inductance with a second load-side branch connection point.

30 . The converter arrangement of claim 18 ,
wherein the at least first and second modular multilevel converters are galvanically connected via a load-side phase connection point to a load or a power source; wherein the load-side phase connection point is connected via a first load-side inductance with a first load-side branch connection point and via a second load-side inductance with a second load-side branch connection point.

31 . The converter arrangement of claim 16 ,
wherein the controller is adapted for closing the switch after a predefined time (ΔT) after the switching the converter cells to zero output voltage; and/or wherein the predefined time does not differ more than 10% from the period of a frequency of a current in the branch connection point.

32 . The converter arrangement of claim 16 ,
wherein the converter arrangement comprises at least two modular multilevel converters, which are connected in parallel via a common phase connection point and/or at least two modular multilevel converters, which are connected in series via a DC link; wherein the converter arrangement comprises a protection system for each of the at least two converters; wherein, when receiving a fault signal, one first protection system is adapted for transmitting the fault signal to another second protection system, which is adapted for switching converter cells of an associated converter to zero output voltage and for closing an associated switch, when

Assignees

• Abb Technology Ag

Inventors

• Steimer Peter

Classifications

• H02M1/32

  Means for protecting converters other than automatic disconnection · CPC title

• H02M2001/0009

  Electricity · mapped topic

• H02M5/44 Primary

  using discharge tubes or semiconductor devices to convert the intermediate DC into AC · CPC title

• H02M7/4835

  comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage · CPC title

• H02M7/493

  the static converters being arranged for operation in parallel · CPC title