| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of abnormal noises and vibration by suppressing uncontrollable region caused by induced voltage generated at the time of handle returning and avoiding the transmission of a spike current to an assist motor. SOLUTION: This device comprise an H bridge circuit that four switching elements are connected in an H bridge shape to an assist motor 6, a steering state discriminating part 30 which, based on steering torque direction and motor rotating direction, monitors steering condition and also discriminates uncontrollable state, and a driving characteristics control part 20 which controls changes in driving characteristics in a manner that under a normal steering condition, the switching element of an upper side FET 50a is driven by PWM at a first duty ratio, and when steering condition that uncontrollable region is generated is discriminated, the switching element of a lower side FET 50b is driven by PWM at a second duty ratio different from the first duty ratio. |
