Patent ID: 9024474
Filing Date: 2015-05-05
Classification: H02J,H03K

Abstract:
1. An uninterruptible power supply, comprising: a first input configured to receive an input AC voltage from a power source, the input AC voltage having an associated phase angle; a second input configured to receive an input voltage from an inverter coupled to a backup power source; an output configured to provide output power derived from power from at least one of the power source and the backup power source; a relay configured to couple the first input with the output in a first position, to couple the inverter with the output in a second position, and to decouple the first input with the output in the second position; a controller configured to detect a voltage swell condition of the input voltage, and responsive to detection of the voltage swell condition, control the relay to switch from the first position to the second position during a predefined range of phase angles of the input AC voltage.