| 摘要 |
PURPOSE:To eliminate a rotor position sensor so as to reduce the number of parts by initially setting a stator winding in a specific exciting phase through application of a starting signal, stepping the stator winding to next exciting phase upon elapse of a predetermined time and then advancing the exciting phase step by step in synchronization with transition of the output from a speed sensor. CONSTITUTION:At the time of starting, a speed command voltage VREF is set and then a reset signal RS is applied thus producing a rectangular starting pulse signal ST having pulse width T. A stator field Ho is produced forcibly by applying the starting signal ST. When a rotor 1 is not at a position matching with the exciting phase of the field Ho, it is rotated to a rotational position matching with the exciting phase. Power is then fed from a pulse sequence circuit 4 to windings U to W thus producing a stator field H1. Pulses are produced from a tachometer generator as the rotor 1 rotates and the output of the pulse sequence circuit advances to next commutation pulse. |
