| 摘要 |
PURPOSE:To drive a motor with optimal conduction timing at all times by detecting a voltage induced in the driving coil of the motor and switching conduction of the driving coil and then setting the conduction timing and conduction time for next conduction phase based on the conduction time of current conduction phase. CONSTITUTION:The drive unit for brushless motor comprises a circuit 8 for switching the conduction state of the driving coils 2a-2c of a motor so that positive torque is produced when the rotational direction of a rotational direction command signal coincides with that of the motor whereas negative torque is produced when they do not coincide with each other, means 7 for generating several phases of conduction switching pulse upon elapse of predetermined delay time after generation of reference phase pulse. Voltages induced in the driving coils 2a-2c of the motor is then detected and conduction switching signals therefor are created. Consequently, the motor can be driven with an optimal conduction timing at all times regardless of the motor speed. Furthermore, when the rotational direction of motor is switched, the motor can be rotated efficiently in reverse direction with the optimal conduction timing by means of a brake circuit 9. |
