| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a snubber circuit for making maximum voltage applied to a semiconductor element to be constant during starting and during overload control without deteriorating device efficiency. <P>SOLUTION: A power conversion apparatus includes a first series circuit where a snubber capacitor and a first diode are connected in series, and a second series circuit where a second diode and a transistor are connected in series. The first series circuit is connected to an output end of a rectifier circuit, and one end of the second series circuit is connected to a series connection point of the snubber capacitor and the first diode of the first series circuit. The other end is connected to a series connection point of a smoothing inductor and a smoothing capacitor of a smoothing circuit. A Zener diode is connected to a base terminal of the transistor of the second series circuit. Potential of the series connection point of the second diode and the transistor of the second series circuit is controlled to a prescribed value. Thus, loss occurring in the transistor of the second series circuit is reduced while LC resonance is effectively suppressed. <P>COPYRIGHT: (C)2012,JPO&INPIT |
