UNINTERRUPTIBLE POWER SUPPLY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an uninterruptible power supply device that makes a precise deterioration diagnosis of a mounted storage battery.SOLUTION: The uninterruptible power supply device includes: a converter 8 for converting AC power supplied from an AC power supply to DC power; a storage battery 30 for storing the DC power converted by the converter 8; an inverter 12 for converting the DC power stored in the storage battery 30 to AC power to feed a load 32 in the event of a service interruption of the AC power supply; and a voltage detector 20 for detecting a voltage of the discharge power from the storage battery 30. The voltage detector 20 discriminates a deterioration mode of the storage battery 30 on the basis of the detection value of the discharge voltage of the storage battery 30, and makes a deterioration diagnose of the storage battery 30 on the basis of a deterioration characteristic of an internal state value of the storage battery 30 with usage in the discriminated deterioration mode.