| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an uninterruptible power supply device of lower cost and smaller size by reducing a discharge current flowing a DC-DC converter at commercial power source failure. <P>SOLUTION: A DC-DC converter 5 that normally charges a storage battery steps up and discharges a storage battery 7 at commercial power source failure so that a DC power is supplied to an inverter 3. The operation of a converter 2 which converts AC to DC when a commercial power source is normal is stopped on the occurrence of failures with a commercial power source 1, and a switch 13 keeps the converter 2 and the storage battery 7 in connected state. Under this condition, a switching element 22 of the converter 2 operates in the same manner as the DC-DC converter 5, to allow the storage battery 7 to supply power to the inverter 3. With this configuration, a plurality of DC-DC converters are allowed to operate at commercial power source failure, reducing the currents flowing the DC-DC converter 5. The cost of the switching elements 21 and 22 can be reduced while the number of workers can be decreased, with a reactor for the DC-DC converters being miniaturized. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
