| 摘要 |
PURPOSE:To prevent the control performance from decreasing in the basis of the continuation of an armature current at a light load time by forcibly reducing the magnetic flux command value of a magnetic flux control loop smaller than the prescribed value when the armature current becomes the certain level or lower. CONSTITUTION:When an armature current IM becomes a certain value IM1 or larger, it is designed to output the prescribed magnetic flux command phi*, while the certain value or smaller, it is designed to output a value decreasing proportionally to the current IM. Assume that an interrupting point of an armature current when the load becomes light while the magnetic flux command phi* remains as it is P1, the current interrupting point moves to the lower value as P2 if as the magnetic flux command value becomes smaller than phi*. Thus, even if the load becomes light, the interruption of the armature current can be avoided. In this manner, the decrease in the control performance on the basis of the interruption of the armature current can be prevented at the light load time. |
