US 9,812,990 B1
Spare on demand power cells for modular multilevel power converter
Zhongyuan Cheng, Kitchener (CA); and Navid Reza Zargari, Cambridge (CA)
Assigned to Rockwell Automation Technologies, Inc., Mayfield Heights, OH (US)
Filed by Rockwell Automation Technologies, Inc., Mayfield Heights, OH (US)
Filed on Oct. 18, 2016, as Appl. No. 15/296,472.
Claims priority of provisional application 62/399,560, filed on Sep. 26, 2016.
Int. Cl. H02M 7/538 (2007.01); H02M 7/5387 (2007.01); H02P 27/08 (2006.01)
CPC H02M 7/53871 (2013.01) [H02P 27/08 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A multiphase multilevel inverter, comprising:
a plurality of inverter phase leg circuits, each phase leg circuit including a plurality of inverter stages connected in series between a corresponding one of a plurality of inverter phase output nodes and a corresponding one of a plurality of inverter phase first nodes to provide a phase voltage signal at the corresponding inverter phase output node, each inverter stage comprising:
an inverter stage output, and
a switching circuit including a plurality of switching devices coupled between a corresponding DC voltage source and the inverter stage output, the switching circuit operative to provide an output voltage having an amplitude of one of at least two discrete levels at the inverter stage output according to a plurality of switching control signals; and
a spare stage system, including:
a spare inverter stage, including a spare stage output, and a spare stage switching circuit including a plurality of spare stage switching devices coupled between a spare stage DC voltage source and the spare stage output, the spare stage switching circuit operative to provide an output voltage having an amplitude of one of at least two discrete levels at the spare stage output according to a plurality of spare stage switching control signals, and
a switch circuit operative in a first mode to connect all the inverter phase first nodes to a common connection node, and in a second mode to connect the spare inverter stage between a selected one of the plurality of the inverter phase first nodes and the common connection node and to connect remaining inverter phase first nodes with the common connection node.