| 摘要 |
PURPOSE:To enable three-phase bilateral energizing without providing a position sensing element by forming a pulse signal similar to an output signal of the position sensing element from a voltage induced in a stator keel. CONSTITUTION:During a period in which no drive current is supplied, a zero- crossing point of an induced voltage of stator coils L1-L3 is detected by comparators 6-7. A pulse signal having an edge at this detected zero-crossing point is processed by EX-OR gates 11-13 and further delayed 30 degrees by monostable multivibrators 21-23 so that a pulse signal equivalent to an output signal of the position sensing element is formed. On the basis of said pulse signal, switching transistors 51-53 and 61-63 are driven to perform a bilateral energizing. |
