| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that cost reduction and miniaturization of an uninterruptible power supply unit is required. <P>SOLUTION: A serial circuit of first and second switches Q1, Q2, a serial circuit of a third and fourth switches Q3, Q4, and a serial circuit of fifth and sixth switches Q5, Q6 are connected between a positive side DC conductor 76 and a negative side DC conductor 77. An AC input terminal 4 is connected to a mutual connection point 8, between the first and second switches Q1, Q2. A mutual connection point 10 between the fifth and sixth switches Q5, Q6 is connected to the AC output terminal 6. A storage battery 83 for backup is connected to a conversion circuit, consisting of the first-sixth switches Q1-Q6 via a backup switch 82. Even if the input frequency is out of a normal range, power supply is not immediately switched to power supply from the storage battery 83 for backup but continues AC-DC-AC conversion, when a load 11 lies within a permissible frequency fluctuation range to suppress deterioration in the capacity of the storage battery 83. <P>COPYRIGHT: (C)2010,JPO&INPIT |
