| 摘要 |
PROBLEM TO BE SOLVED: To make a switch to a sensorless operating state through a simple constitution in a very short time and to detect the rotor position accurately after switching. SOLUTION: An external synchronization signal SS for rotary accelerating a rotor 14 is applied to a commutator section 21 and the application is interrupted upon elapse of a predetermined time. Subsequently, a position feedback drive signal generating section 41 produces commutation control signals AU-BL using sensorless signals ZA, ZB, ZC, received from a position detector 50 based on the voltages EA, EB, EC induced reversely in drive windings 11-13 and controls the commutator section 21 thus performing the commutation of driving current to the drive winding depending on the rotor position. |
