| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an uninterruptible power supply device that will not have a part of a load current waveform from interrupted, even when power factor improvement control accuracy by a parallel converter is poor, or when there is no power factor improvement control in the uninterruptible power supply device that supplies input power, supplied from a commercial power supply, to a load, while converting DC power of a battery into AC power so as to supply it to the load as AC power during a failure of the commercial power supply. <P>SOLUTION: A control circuit of the uninterruptible power supply device controls a changeover switch so that a switching element of the changeover switch maintains the conductive state for a longer interval than a half-cycle interval, to which the switching element corresponds, of the polarity of the input-voltage, and that the longer interval is either of an interval generated, by adding a beginning part of the conductive interval to the half-cycle interval and an interval generated by adding an end part of the conductive interval to the half-cycle interval. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
