| 摘要 |
PROBLEM TO BE SOLVED: To provide a brushless motor and its drive controller which can suppress current fluctuation, torque fluctuation and noise of the brushless motor and by which a motor-driven power steering device with low noise and satisfactory steering feeling can be realized. SOLUTION: This drive controller of a brushless motor has a current change rate control means which controls the current change rate at the time of commutation, and a plurality of excitation phases. The current change rate control means makes a transient time of commutation, which is a period while a phase current is in a transient state in a commutation operation, shorter than a half of the commutation interval time, which is a period between one commutation start time and a next commutation start time. |
