US 11,817,738 B2
Fault condition detection system and method
Kristian Budde, Kolding (DK); Jesper Hougaard Johansen, Vejen (DK); and Jacob Gregers Hansen, Kolding (DK)
Assigned to SCHNEIDER ELECTRIC IT CORPORATION, Foxboro, MA (US)
Filed by SCHNEIDER ELECTRIC IT CORPORATION, Foxboro, MA (US)
Filed on Sep. 20, 2021, as Appl. No. 17/479,227.
Application 17/479,227 is a continuation of application No. 16/815,094, filed on Mar. 11, 2020, granted, now 11,128,164, issued on Sep. 21, 2021.
Prior Publication US 2022/0109322 A1, Apr. 7, 2022
Int. Cl. H02J 9/06 (2006.01); H02J 1/10 (2006.01); H02M 3/158 (2006.01)
CPC H02J 9/061 (2013.01) [H02J 1/108 (2013.01); H02M 3/158 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An uninterruptible power supply, comprising:
a first input configured to receive input power;
a backup input configured to receive backup power from a backup power source;
an output configured to provide output power to a load derived from at least one of the input power or the backup power;
a bypass switch having a first connection coupled to the first input and a second connection coupled to the output; and
a controller coupled to the bypass switch and configured to:
determine a voltage difference across the bypass switch;
compare, based on the voltage difference across the bypass switch, input harmonics of a first voltage at the first connection of the bypass switch with output harmonics of a second voltage at the second connection of the bypass switch; and
output an indication of a failure of the bypass switch based on the comparing of the input harmonics and the output harmonics.