| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a three-level converter capable of isolating DC smoothing capacitors from a short-circuit portion when a short-circuit failure occurs, and even capable of isolating an abnormal charging loop from an AC power source. <P>SOLUTION: When a short-circuit failure occurs, protective fuses 28, arranged in the paths connecting AC input points to the middle point of the DC smoothing capacitors 25, 26, are fused by a short-circuit current that flows from the DC smoothing capacitors 25, 26. This structure prevents a subsequent abnormal charging of the DC smoothing capacitors 25, 26 by the AC power source 11 and thereby prevents the expansion of failure damage. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
