| 摘要 |
PURPOSE:To accurately detect a magnetic flux without using a magnetic flux sensor by calculating the flux from the primary current of an induction motor and using for the feedback control of the magnetic flux. CONSTITUTION:A magnetic flux phi0 is obtained in a 3-phase/2-phase converter 40, a coordinates converter 50 and a magnetic flux calculator 60 on the basis of the primary currents iu, iv of an induction motor 20 detected by current detectors 31, 32. The flux phi0 is obtained as the difference from a magnetic flux command phi0* in a subtractor 17, and a magnetic flux controller 15 controls a magnetic flux current command value I1d* to equalize the flux phi0 to the value phi0*. A torque current command value I1q* and an angular frequency command value omega0* are decided by a torque command value tau*, and the primary current of the motor 20 is controlled in a current control frequency converter 18 on the basis of the command values I1a* and I1d*. |
