| 摘要 |
PROBLEM TO BE SOLVED: To provide a control apparatus for an induction motor, which does not fall into a control impossibility even in an ultralow-speed regenerative mode. SOLUTION: A primary-angular-frequency instruction-value computing part 17 outputs a primary-angular-frequency instruction value ω1*' which has the magnitude of a primary- angular-frequency reference value ω1* and which comprises both a positive polarity and a negative polarity when the primary angular frequency ω1, of an induction motor 5, computed by a primary-angular-frequency computing part 12 is less than the primary-angular-frequency reference value ω1*. A torque-portion-current correction part 16 obtains a torque-portion- current correction value Δi1q on the basis of the deviation between the primary-angular- frequency instruction value ω1*' and the primary angular frequency ω1, and it adds the torque-portion-current correction value Δi1q to a torque-portion-current instruction value i1q* so as to output a torque-portion-current correction instruction value i1q*'. A torque- portion-current control part 10 performs a computing operation on the basis of the deviation between the torque-portion-current correction instruction value i1q*' and a torque-portion- current detection value i1q, and it drives the induction motor 5 by a sensorless vector control operation which is based on an obtained torque portion, on an excitation-portion-current correction output and on a phase angle θ from a phase-angle computing part 13. |
