| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a low cost steering controlling device capable of certainly separating a motor driving circuit from a three-phase AC motor in a failure. <P>SOLUTION: The steering controlling device 40 includes the motor driving circuit 43 having a V-phase feeder line 42V and a W-phase feeder line 42W, which are furnished with emergency switching elements 51 and 52 to be semiconductor switching elements. The emergency switching elements 51 and 52 of the V-phase feeder line 42V are turned off when the absolute of the current Iv in the V-phase feeder line 42V has become the prescribed reference value K1 or below in the event of failure occurrence, and the remaining emergency switching elements 51 and 52 are turned off when the absolutes of the current values Iu and Iw in the remaining feeder lines 42U and 42W have become the prescribed reference value K1 or below. This allows suppressing the spike voltage. <P>COPYRIGHT: (C)2010,JPO&INPIT |
