Patent ID: 9154000
Filing Date: 2015-10-06
Classification: H02J

Abstract:
1. An uninterruptible power supply apparatus, comprising: a converter converting first AC electric power supplied from a commercial AC power supply to DC electric power; an inverter converting the DC electric power supplied from said converter or a power storage device to second AC electric power having a commercial frequency; a DC power supply generating a DC power supply voltage based on said second AC electric power; a first switch having one terminal receiving said first AC electric power and the other terminal connected to a load; a second switch having one terminal receiving said second AC electric power and the other terminal connected to said load; and a control circuit driven by said DC power supply voltage, said control circuit having: a first mode in which said first switch is brought out of conduction, said second switch is brought into conduction, and said converter and said inverter are operated to supply said second AC electric power to said load; a second mode in which said first switch is brought out of conduction, said second switch is brought into conduction, operation of said converter is stopped, and said inverter is operated to supply said second AC electric power to said load; a third mode in which said first and second switches are brought out of conduction to stop electric power supply to said load, and the operation of said converter is stopped and said inverter is operated to supply said second AC electric power to said DC power supply; and a fourth mode in which said first switch is brought into conduction and said second switch is brought out of conduction to supply said first AC electric power to said load, said control circuit executing said first mode in a normal state in which said first AC electric power is supplied from said commercial AC power supply; executing said second mode at the time of power failure in which supply of said first AC electric power from said commercial AC power supply is stopped; executing said third mode at the time of discharge end in which an output voltage of said power storage device decreases to a predetermined voltage during said power failure; and executing said fourth mode, and thereafter, executing said first mode when supply of said first AC electric power from said commercial AC power supply is resumed at the time of said discharge end.