| 摘要 |
PROBLEM TO BE SOLVED: To suppress the sudden change of a motor output at the time of the commutation delay change, and reduce the change of a motor revolution and an impact to a motor load. SOLUTION: An AC power supply 1 is rectified by a rectifying circuit 2 and supplied to a 3-phase DC brushless motor 4 through semiconductor switching devices 3 which are connected to each other into a 3-phase bridge circuit. The position of a rotor is detected by a position detection unit 5 in accordance with the changes of motor terminal voltages and, further, a commutation delay is reduced from a delay A1 to a delay A2 and, when the set commutation delay time passes after the position detection signal is obtained, a stator winding to which a current is applied is successively switched by a current applied winding switching unit 7. As a result, even if the flux saturation is suppressed, in accordance with a motor applied voltage which is reduced from a voltage V1 to a proper voltage V2 by an applied voltage setting unit 6 at the same time, the semiconductor switching devices 3 are driven by a Tr. driving signal generating unit 8 to operate the motor. With this constitution, a motor output does not rise suddenly and the fluctuation of the motor revolution and an impact to a motor load can be reduced. |
