| 摘要 |
PURPOSE: To stabilize the rotation of a brushless motor while reducing vibration and noise by switching the conduction of an armature winding appropriately using an inexpensive microcomputer as a control circuit for the brushless motor. CONSTITUTION: A comparison circuit 10b compares the terminal voltage (induced voltage) of the armature winding of a brushless motor 3 with a reference voltage and a control circuit 11 detects a position signal D varying at an intersection. Time T of a single period (electric angle of 360 deg.) after variation and the times corresponding to electric angles of 30 deg., 90 deg. and 150 deg. are then calculated. The time corresponding to an electric angle of 30 deg. is determined before the current variation point of the position signal D whereas the times corresponding to electric angles of 90 deg. and 150 deg. are determined after the current variation point of the position signal D. The time thus determined is then measured and conduction of the armature winding of the brushless motor 3 is switched upon expiration of the determined time. |
