| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve cost reduction by making it possible to use an element having a low withstand voltage by reducing a surge voltage at the time of forcible disconnection caused by an output short circuit or the like, and by improving reliability. <P>SOLUTION: The figure shows circuits of two phases of an inverter. An overcurrent set value Vceoc1 of the upper arm side gate drive circuit is adapted to differ from an overcurrent set value Vceoc2 of the lower arm side gate drive circuit. Briefly, the figure shows an example of Vceoc1≠Vceoc2. By this constitution, if a U phase and a V phase are short-circuited and a short-circuited current flows in a dot-line passage shown in the figure, for example, IGBTs 4a, 4b that are the switching elements are forcibly disconnected with mutually different Vce values (current corresponding values) by the above difference, thus enabling the reduction of the surge voltage that is generated by the concurrent disconnection of the IGBTs 4a, 4b. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
