| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain an uninterruptible power supply unit that supplies electric power to a load stably by suppressing overcurrent/an overloading of a semiconductor switch. <P>SOLUTION: A power conversion circuit comprises the semiconductor switch 3, one end of which is connected to a commercial power source 1, the other end of which is connected to the side of a load 2, and a bidirectional converter 4 connected to the load side of the semiconductor switch. Normally, the commercial power source supplies electric power to the load via the semiconductor switch, and the converter is in a DC voltage control state to charge a DC power source 5. In this power conversion circuit, a control circuit 11 is provided such that, if the current flowing in the semiconductor switch exceeds a rated value, a command directing the converter to supply a portion of the current exceeding the rated value is sent so as to make the converter bear a portion exceeding the rated value of the current flowing in the semiconductor switch, while making the DC power source charged. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
