| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an uninterruptible power supply system capable of changing over two UPSs, without switching to a commercial power supply system once by a comparatively simple circuit configuration. <P>SOLUTION: The system is constituted of two uninterruptible power supply systems 10 and 20, a switch 80 connecting the output buses of the two uninterruptible power supply systems and a synchronous control circuit 50, by using an output voltage from each uninterruptible power supply system as input and controlling the output from one uninterruptible power supply system so that the frequency and phase of one output voltage are synchronized with those of the other output voltage. The system is further constituted of a current error control circuit 60, by using an output current from each uninterruptible power supply system as input and controlling the output voltages and phases of the two uninterruptible power supply systems so that their output currents are balanced. When the synchronous control circuit 50 is given a start command, the synchronous control circuit 50 is actuated; and the synchronism of mutual phases is confirmed; the switch 80 is closed; and the current error control circuit 60 is actuated, to enable the two uninterruptible power supply systems to operate in parallel. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
