| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce an average switching frequency without changing a frequency of a carrier wave and hereby suppress switching loss. <P>SOLUTION: For PWM-controlling a power conversion device for converting three-phase AC voltage into DC voltage or performing inverse conversion based on a comparison result of a three-phase AC voltage signal and the carrier wave, the average switching frequency is reduced by using a carrier wave C2 like a solid line, which is obtained by correcting a relative position with respect to the three-phase AC voltage signal wave of the carrier wave at every half period of a carrier wave C1 shown by a dotted line, in accordance with amplitude values of phase signal waves U1, V1 and W1 of the three-phase AC voltage signal wave. <P>COPYRIGHT: (C)2008,JPO&INPIT |
