US 11,791,710 B2
Switching sequence controlled current steering for stacked half bridge converters
Jie Lu, Cupertino, CA (US); Brandon Pierquet, San Francisco, CA (US); and Ashish K. Sahoo, Santa Clara, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Feb. 23, 2021, as Appl. No. 17/182,856.
Prior Publication US 2022/0271646 A1, Aug. 25, 2022
Int. Cl. H02M 5/293 (2006.01); H02M 7/483 (2007.01); H02M 1/15 (2006.01); H02M 7/53 (2006.01); H02M 3/335 (2006.01); H02M 1/00 (2006.01)
CPC H02M 1/15 (2013.01) [H02M 5/293 (2013.01); H02M 7/53 (2013.01); H02M 1/0054 (2021.05); H02M 1/0074 (2021.05); H02M 1/0095 (2021.05); H02M 3/33571 (2021.05); H02M 7/4833 (2021.05)] 19 Claims
OG exemplary drawing
 
1. A stacked half-bridge AC-AC converter comprising:
a first half bridge including a first switching device and a second switching device, wherein a junction point of the first and second switching devices is coupled to a first AC output terminal of the converter;
a second half bridge including a third switching device and a fourth switching device, wherein a junction point of the third and fourth switching devices is coupled to a second AC output terminal of the converter and wherein the first and second half bridges are connected in a ladder configuration across an AC input of the converter;
first and second input capacitors connected in a ladder configuration across the AC input of the converter, wherein a junction point of the first and second capacitors is connected to a junction point of the first and second half bridges forming a neutral point of the converter; and
a controller configured to operate the switching devices according to a plurality of switching sequences, each switching sequence including one or more switching patterns, and each switching pattern including a plurality of switching states, each switching state including pulse width modulated operation of at least one switching device from each of the first and second half bridges, wherein:
at least one of the plurality of switching sequences includes one or more patterns of switching states selected to inject current into the neutral point to regulate a voltage of the neutral point, reduce switching losses, or equalize losses among the switching devices.