| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an invertor device that can optimally, or nearly optimally set the switching frequency of a switching element, can rationally prevent the switching element from being damaged thermally, and can easily and rationally prevent the occurrence of magnetic noise (magnetostrictive sound) based on the switching frequency. <P>SOLUTION: A radiator 6 is provided to thermally protect first-sixth switching elements Q1-Q6 of a DC-AC conversion circuit 3 in the invertor device. A temperature detector 7 is connected to the radiator 6. A means is provided for estimating the temperature of the radiator 6 by operation. The difference is obtained between the estimated and detected values of the temperature of the radiator 6. The difference allows the switching frequency of the first-sixth switching elements Q1-Q6 to be controlled. When the difference is large, the switching frequency is set to be an inaudible frequency. <P>COPYRIGHT: (C)2007,JPO&INPIT |
