| 摘要 |
PROBLEM TO BE SOLVED: To provide a drive unit of brushless motor which can suppress step-out or torque reduction immediately after switching from rectangular wave drive to sine wave drive.SOLUTION: In a drive unit for rotary driving a brushless motor by rectangular wave driving in a low speed region, and rotary driving a brushless motor by sine wave driving in a high speed region, switching is made from rectangular wave driving to sine wave driving when a known predetermined angular position is detected after detecting transition from low speed region to high speed region. As the predetermined angular position, an angular position where the output pattern (conduction mode) is switched in the rectangular wave driving, or an angular position where the motor torque has a peak value in the rectangular wave driving is set. |
