FLUX PROFILE CONTROL FOR STARTUP OF AN INDUCTION MOTOR

摘要

A method of controlling current in an AC motor to inhibit small torques on an unloaded motor output shaft and to improve buildup of steady state operating flux in a rotor includes supplying current to the stator windings through a plurality of semiconductor switches, operating the semiconductor switches to supply a plurality of gradually increasing currents to the stator windings over a time interval corresponding to approximately one rotor time constant to bring flux in the rotor up to approximately 10% of a steady-state operating flux in the rotor, operating the semiconductor switches to supply a current that is the maximum current rated for pulsed operation of the semiconductor switches for a time interval over which a product of current and time is sufficient to produce steady-state operating flux in the rotor, and then reducing the stator current to a level for maintaining steady state operating flux in the rotor. A microelectronic apparatus for carrying out the method is also disclosed.