UNINTERRUPTIBLE POWER SUPPLY DEVICE

An uninterruptible power supply device includes: an inverter configured to convert AC power from an AC power supply into DC power and output the DC power to a DC bus; a converter configured to convert the DC power received from the DC bus into AC power and supply the AC power to a load; a bidirectional chopper configured to transmit and receive DC power between the DC bus and a storage battery; a bidirectional chopper configured to transmit and receive DC power between the DC bus and a lithium ion battery; a controller configured to cause the storage battery to be charged during normal operation, and to be discharged during power failure; and a controller configured to cause the lithium ion battery to be charged when the load is performing a regenerative operation, and to be discharged when the load is performing a power running operation.