| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress torque variation of a three-phase motor caused by a fail safe relay interposed between a motor driving circuit and the three-phase motor of an electric power steering device. <P>SOLUTION: When a U-phase line 62U and a V-phase line 62V of the U-phase line 62U, the V-phase line 62V and a W-phase line 62W for connecting the motor driving circuit C to the three-phase motor M can be opened by the fail safe relay, current flowing through the W-phase line 62W is increased by a predetermined amount so that the effect of the contact resistance is compensated and currents flowing through respective phase lines 62U, 62V and 62W are equal. Therefore, the variation of the output torque of the three-phase motor M can be suppressed to increase the steering feeling. Especially, a predetermined current is made to flow through the U-phase line 62U and the V-phase line 62V, the resistance is calculated, and the corrective amount of the current flowing through the W-phase line 62W is calculated based on the resistance, so that the currents flowing through respective phase lines 62U, 62V and 62W can be accurately matched with each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
