Patent ID: 8890374

Claim:
An uninterruptible power supply system for avoiding arcing generation and providing a stable output voltage, said uninterruptible power supply system comprising: plural power units for converting an input voltage into said output voltage, and transmitting said output voltage to a power output side of said uninterruptible power supply system; plural output capacitor units electrically connected to output sides of respective power units; a capacitor energy bleeder circuit electrically connected to said plural output capacitor units; plural output units electrically connected to said output sides of respective power units, so that said plural power units are connected with each other in parallel to issue said output voltage to said power output side and avoid returning electrical energy from said power output side back to said capacitor energy bleeder circuit; a detecting unit for detecting operating statuses of said plural power units; and a controlling unit electrically connected to said detecting unit, said capacitor energy bleeder circuit and said plural power units for controlling operations of said plural power units and said capacitor energy bleeder circuit, wherein in response to a to-be-interrupted status of any power unit of said plural power units, said controlling unit controls said capacitor energy bleeder circuit to discharge electrical energy of said output capacitor unit corresponding to said any power unit of said plural power units.