US 12,244,244 B2
Fault tolerant system and method for continuous skip-fire pulse width modulation for an active neutral point clamped converter
Pushkar Chandrakant Chaudhari, Bengaluru (IN); Kapil Jha, Bengaluru (IN); Fernando Arturo Ramirez Sanchez, Salem, VA (US); and Nathaniel Robert Michener, Roanoke, VA (US)
Assigned to General Electric Renovables Espana, S.L., Barcelona (ES)
Filed by General Electric Renovables Espana, S.L., Barcelona (ES)
Filed on Apr. 28, 2022, as Appl. No. 17/731,780.
Prior Publication US 2023/0353039 A1, Nov. 2, 2023
Int. Cl. H02M 7/487 (2007.01); H02M 1/14 (2006.01); H02M 1/32 (2007.01); H02M 5/458 (2006.01)
CPC H02M 7/487 (2013.01) [H02M 1/14 (2013.01); H02M 1/32 (2013.01); H02M 1/325 (2021.05); H02M 5/4585 (2013.01)] 9 Claims
OG exemplary drawing
 
6. A multi-level bridge power converter with a plurality of phase legs, comprising:
a first converter and a second converter coupled together via a DC link, each of the first and second converters comprising a plurality of switching devices;
a controller configured to operate the first and second converters in a fault-tolerant operational mode when one of the plurality of switching devices in the first converter or in the second converter is failed in a shorted state, the controller configured to:
implement an on/off scheme for the plurality of switching devices in the first and second converters that provides for continuous fault-tolerant operation of the respective converter when one or more of the plurality of switching devices in the respective converter has failed in the shorted state, wherein the on/off scheme is dependent upon phase current direction through the respective converter;
indirectly determine the phase current direction through the respective converter by sensing a pole voltage of the respective converter; and
implement the on/off scheme when the pole voltage changes from zero to a +/−value indicating that the phase current through the respective converter has switched direction;
wherein the plurality of switching devices in each of the first and second converters comprises at least four inner switching devices and at least two outer switching devices in an active neutral point clamped topology, wherein the first and second converters connect to the DC-link by the controller turning on the at least four inner switching devices, and wherein in the fault-tolerant operational mode one of the at least two outer switching devices is failed in the shorted state and the on/off scheme implemented by the controller prevents a current shoot-through across the DC-link when connecting the first converter or the second converter to the DC-link;
wherein the plurality of switching devices are designated as a first switching device through a sixth switching device, wherein the second, the third, the fifth, and the sixth switching devices are the at least four inner switching devices, and the first switching device and the fourth switching device are the at least two outer switching devices, wherein in the on/off scheme of the fault-toleration operation:
when the first switching device is failed in the shorted state, the second switching device and the sixth switching device are on and the fifth switching device and the third switching device are off; or
when the fourth switching device is failed in the shorted state, the third switching device and the fifth switching device are on and the second switching device and the sixth switching device are off; and
a voltage sensor configured to detect the pole voltage of the respective converter, the voltage sensor is in communication with the controller.