To provide a vector controller of an induction motor in which lowering of torque characteristics can be avoided by suppressing increase in output voltage command upon sudden acceleration of a field-weakening region and varying the flux of an induction motor quickly even upon sudden slowdown.
The vector controller of induction motor comprises a coordinate conversion means, an exciting current control means (ACRd), a torque current control means (ACRq), a slip frequency command operating means, a primary frequency command operating means, and a voltage type inverter for controlling an induction motor using the outputs from the exciting current control means (ACRd) and the torque current control means (ACRq) as a primary voltage command. Furthermore, a means for varying a rated slip frequency command value set in the slip frequency command operating means is provided.
NAKAI MASAKI
SAWAMURA MITSUJIRO
