| 摘要 |
PROBLEM TO BE SOLVED: To improve efficiency a motor by reducing motor's core loss caused by PWM control. SOLUTION: A DC voltage commutated with a commutation means 10 is supplied to drive coils 1-3 of a motor through a PWM control corresponding to rotation speed information. Relating to the commutation means 10, switch means 14 is so controlled with a control unit 11 so that a full-wave commutation is performed when the motor is at a specified number of rotation or below, for the motor to be at a specified number of rotation or above, for double- voltage commutation. Since, under a specified number of rotation or below, a low voltage is supplied by all-wave commutation, the fluctuation of a motor current caused by PWM control becomes less, so that a core loss is reduced. |
