| 摘要 |
PURPOSE:To make it possible to control a current conduction angle in correspondence with applications and to improve efficiency, by performing the control so that current conduction through stator windings is made in one direction by the detected output of a counter electromotive force, and omitting special provision of a position detecting mechanism. CONSTITUTION:In the vicinity of time T1, when the counter electromotive voltages 11-2a and 11-3a are lower than 11-1a and the counter electromotive voltage is generated in the stator winding 11-1 in the direction of an arrow C, the potential at a terminal 19 becomes higher than that of a terminal 18. Then a transistor 25 is turned ON by the detected signal of the counter electromotive voltage from an operation amplifier 22, which is amplified to the more positive direction than the voltage at a reference voltage terminal 29-3. Therefore a current is conducted through a bridge circuit including the stator winding 11-1. When a rotor is rotated and the counter electromotive voltage is generated in the stator winding 11-2 in the direction of an arrow D (in the vicinity of time T3), a transistor 26 is turned ON by the output of a counter electromotive voltage detecting circuit 12-2 as described before, and a current is conducted through a bridge circuit including the stator winding 11-2. A current is conducted in the following circuits by the same way. |
