| 摘要 |
PROBLEM TO BE SOLVED: To obtain the relatively small-sized power converter of simple constitution with a protecting function for an overcurrent by suppressing breakage due to the overcurrent cutoff of other switching elements by performing gate driving different from other switching elements for >=1 switching element at overcurrent time such as short-circuiting by the overcurrent detecting function of a gate driving circuit. SOLUTION: When an overcurrent is detected, a switching element 21a is used as a protection cutoff element and if the element 21a is broken, a signal indicating the one element is broken is sent to a controller 6 by a signal transmitting means such as an optical fiber. Further, this signal is transmitted to the gate driving unit 23b of another switching element 21b and if short-circuiting is caused again, this element 21b is used as a protection cutoff element. If two elements 21a and 21b are broken the off-time voltage exceeds the dielectric strength of an element only by the remaining elements, so it is impossible to continue the operation and then the operation of the converting device is stopped to replace the two broken elements 21a and 21b. |
