| 摘要 |
PURPOSE:To eliminate the stepout of a commutatorless motor at switching time from a synchronous commutation to a self-commutation by varying a curve with respect to the time of chopping duty in response to the value of a DC voltage smoothed by a converter from an AC power at synchronous commutation time. CONSTITUTION:A DC voltage smoothed by a converter 9 from an AC power source 8 is switched by an inverter 10, an AC voltage is applied to a motor winding to operate a motor M2. A voltage between the terminals of the motor winding is input to a position detector 13 to detect the position of a permanent magnet rotor 11, and it is input to a controller 14. The controller 14 varies the chopping duty to approach to a target rotating speed, and a switching signal is fed to the inverter 10. The controller 14 prepares curves of a plurality of chopping duties, the curve adapted for the synchronous commutation is selected in response to the value of the DC voltage at starting time, the lapse of a predetermined time is waited, and it is switched to a self-commutation. |
