METHOD FOR ESTIMATING INDUCED ELECTROMOTIVE FORCE AND SPEED OF INDUCTION MOTOR, METHOD FOR CORRECTING MISALIGNMENT OF SHAFT THEREOF, AND INDUCTION MOTOR CONTROLLER

摘要

A three-phase/two-phase converter (10) detects the two-phase component of a three-phase stator current and performs the .gamma.-.delta. coordinate system transformation of the stator current to derive a .gamma.-axis current and a .delta.-axis current. The .gamma.-axis current and the .delta.-axis current are inputted, along with voltage designating values from a .gamma.-axis current controller (2) and a .delta.-axis current controller (3), to a stator current/induced electromotive force estimation unit (9) in order to determine an estimated value of the stator current in the .gamma.-.delta. coordinate system and an estimated value of the induced electromotive force.