| 摘要 |
PURPOSE:To realize a brushless motor drive for domestic appliance or non- military appliance without employing a switching power supply (DC/ DC con verter). CONSTITUTION:The brushless motor drive comprises a rotor position detecting circuit 3, a plurality of driving coils, a conducting state command circuit 4, a frequency generator 36, a speed detecting circuit 5, a phase comparator 31, a PWM circuit 13 for controlling the ON/OFF duty of a switching power element constituting a power circuit, and means for applying a constant DC voltage on the power circuit. According to the constitution, a highly accurate brushless motor drive can be obtained, in which motor speed can be varied even when a constant DC voltage is applied directly on the motor without requiring a conventional switching power supply for varying the rotational speed. |
