| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent overheat of a reactor of a capacitor or a DC-DC converter provided in parallel with a DC power supply on the input side of the DC-DC converter. <P>SOLUTION: When the temperature Tw of cooling liquid for cooling a DC-DC converter is below a set temperature T1 in step S201, the value of flag F1 is set to 0 in step S202 and the frequency fc of a reference carrier is set to a high carrier frequency fh or a low carrier frequency fl based on the temperature Tt of a power transistor. On the other hand, when the temperature Tw of cooling liquid exceeds the set temperature T1 in step S201, the value of flag F1 is set to 1 in step S203 and the frequency fc of the reference carrier is set to a high carrier frequency fh regardless of the temperature Tt of the power transistor, thus prohibiting the use of the low carrier frequency fl. <P>COPYRIGHT: (C)2009,JPO&INPIT |
