ELECTRIC POWER STEERING DEVICE

摘要

An electric power steering device decides a current instruction value to flow to a brushless DC motor according to a detected steering torque, deices voltage to be applied according to a difference between the decided current instruction value and the detected current value flowing to the motor, and applies the decided voltage to the motor for facilitating the steering. According to a detected rotor position, the motor rotation angular velocity is calculated. The motor is judged to have failed if rotation angular velocity judgment means judges that the calculated rotation angular velocity is below a predetermined rotation angular velocity; current instruction judgment means judges that the current instruction value is below a predetermined current value; and voltage judgment means judges that the voltage decided to be applied to the motor is out of a predetermined voltage range.