| 摘要 |
PURPOSE: To prevent stoppage and step-out in a brushless motor, by making a change adequate in energization of a winding of an armature. CONSTITUTION: A voltage from a DC power supply Vdc is switched by an inverter 4 and applied to an armature winding of a brushless motor 3. A rotational state of the brushless motor 3 is controlled by changing a duty ratio in chopping for the applying voltage. In a position detection unit 5, a winding voltage (R) of the armature in the motor 3 is compared with a reference voltage (k) to generate an input position signal (A). The position of a rotor 3a is detected by the position signal (A), and the energization of the winding of the armature is changed on the basis of the position detection. A control circuit calculates a difference in time between an energization changing time and a position detecting time for every detection of the rotor 3a on the basis of the input position signal (A). If the difference in time is larger by a given level than the former one, the control circuit judges the detection time delayed and makes a change in energization of the winding of the armature. |
