Converter Cell with Crowbar

Patent metadata

Field	Value
Publication number	US-2022085731-A1
Application number	US-201917432189-A
Country	US
Kind code	A1
Filing date	Feb 28, 2019
Priority date	Feb 28, 2019
Publication date	Mar 17, 2022
Grant date	—

Abstract

The present disclosure relates to a converter cell (4) for a power converter. The cell comprises a plurality of semiconductor devices (T) forming a half-bridge or full-bridge topology in the cell. The cell also comprises an energy storage (5) connected across the at least one switch leg (6). The cell also comprises a crowbar leg (7) connected across the at least one switch leg, comprising a plurality of series connected semiconductor crowbar switches (C) arranged to short-circuit the energy storage (5). The cell also comprises first and second AC terminals (A, B), wherein at least one of said AC terminals is connected to one of the at least one switch leg, between two of the plurality of series connected semiconductor devices of said switch leg, and connected to the crowbar leg, between two of the plurality of series connected crowbar switches of said crowbar leg.

First claim

1 . A converter cell ( 4 ) for a power converter ( 1 ), the cell comprising:
a plurality of semiconductor devices (T) forming a half-bridge or full-bridge topology in the cell with at least one switch leg ( 6 ) comprising a plurality of the semiconductor devices connected in series, each semiconductor device comprising a switch (S) and an anti-parallel diode (D); an energy storage ( 5 ) connected across the at least one switch leg ( 6 ); a crowbar leg ( 7 ) connected across the at least one switch leg ( 6 ), said crowbar leg comprising a plurality of series connected semiconductor crowbar switches (C) arranged to short-circuit the energy storage ( 5 ) when the crowbar switches are switched to conducting; and first and second AC terminals (A, B), wherein at least one of said AC terminals is connected to one of the at least one switch leg ( 6 ), between two of the plurality of series connected semiconductor devices (T) of said switch leg, and connected to the crowbar leg ( 7 ), between two of the plurality of series connected crowbar switches (C) of said crowbar leg, whereby the first and second AC terminals are arranged to bypass the semiconductor devices (T) via one of said crowbar switches when said one crowbar switch (C 2 ) is switched to conducting.

2 . The converter cell of claim 1 ,
wherein the at least one switch leg ( 6 ) consists of one switch leg, comprising a first (T 1 ) and a second (T 2 ) semiconductor device, forming a half-bridge topology, wherein the plurality of series connected semiconductor crowbar switches (C) consists of a first (C 1 ) and a second (C 2 ) crowbar switch, and wherein the first AC terminal (A) is connected to the switch leg ( 6 ) between the first and second semiconductor devices (T 1 , T 2 ), and connected to the crowbar leg ( 7 ) between the first and second crowbar switches (C 1 , C 2 ).

3 . The converter cell of claim 1 ,
wherein the at least one switch leg consists of a first ( 6 a ) and a second ( 6 b ) switch leg, each comprising a first (T 1 /T 3 ) and a second (T 2 /T 4 ) semiconductor device, forming a full-bridge topology, wherein the plurality of series connected semiconductor crowbar switches consists of a first (C 1 ), a second (C 2 ) and a third (C 3 ) crowbar switch, and wherein the first AC terminal (A) is connected to the first switch leg ( 6 a ) between the first and second semiconductor devices (T 1 , T 2 ) thereof, and connected to the crowbar leg ( 7 ) between the first and second crowbar switches (C 1 , C 2 ), and the second AC terminal (B) is connected to the second switch leg ( 6 b ) between the first and second semiconductor devices (T 3 , T 4 ) thereof, and connected to the crowbar leg ( 7 ) between the second and third crowbar switches (C 2 , C 3 ).

4 . The converter cell of claim 2 or 3 , wherein a reverse crowbar switch (CR) is connected across the second crowbar switch (C 2 ), antiparallel to the second crowbar switch, arranged to allow current to flow from the second terminal (B) to the first terminal (A) via said reverse crowbar switch when switched to conducting.

5 . The converter cell of claim 4 , wherein the second crowbar switch (C 2 ) and the reverse crowbar switch (CR) are comprised in a Bidirectional Control Thyristor, BCT.

6 . The converter cell of any preceding claim, wherein each of the crowbar switches (C) comprises a thyristor.

7 . The converter cell of any preceding claim, wherein each of the switches (S) of the semiconductor devices (T) comprises an Insulated-Gate Bipolar Transistor, IGBT, Bi-Mode Insulated Gate Transistor, BiGT, or an Integrated Gate-Commutated Thyristor, IGCT, preferably an IGBT.

8 . The converter cell of any preceding claim, wherein each of the switches (S) of the semiconductor devices (T) is connected via bond wires.

9 . A power converter ( 1 ) comprising a plurality of series connected converter cells ( 4 ) of any preceding claim.

10 . The power converter of claim 9 , wherein the power converter ( 1 ) is a Modular Multilevel Converter, MMC.

11 . The power converter of claim 9 or 10 , wherein the power converter ( 1 ) is an AC-to-DC converter, e.g. in a double-star topology.

Assignees

• Abb Power Grids Switzerland Ag

Inventors

• Mohanaveeramani Aravind
• Svensson Jan
• Nami Alireza

Classifications

• H02M7/4835 Primary

  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

• H02M7/155

  using semiconductor devices only · CPC title

• H02M7/49

  Combination of the output voltage waveforms of a plurality of converters · CPC title

• H02M7/217 Primary

  using semiconductor devices only · CPC title

• H02M1/325

  with means for allowing continuous operation despite a fault, i.e. fault tolerant converters · CPC title