| 摘要 |
PROBLEM TO BE SOLVED: To accelerate the rotation of a rotor smoothly and speedily by changing over a voltage control in accordance with current conditions during the period when the number of revolutions of the rotor changes sharply from a start. SOLUTION: The rotation of a rotor is induced by impressing excited voltages of the phases corresponding to a sensor 32u which detects a position signal at the time of a startup (t=0) until the sensor detects a first fall (t=t1). In the first cycle after the startup, the excited voltages of the corresponding phases are impressed (t=t3) or interrupted (t=t4) in synchronism with a position signal detected by each sensor. From the second cycle, the voltages are impressed (t=t5, t8) or interrupted (t=t6, t9) after a lapse of a preset delay time from the detection of the position signal by each sensor (t=t4, t7). Then, the delay time is changed over to the value calculated in accordance with the actual number of revolutions of the rotor. |
