Correction of the operating modes of an induction motor with asymmetrical stator windings at vector control

Abstract

Operation of an induction motor with electric or magnetic asymmetry of stator windings results in uneven distribution of losses in copper across stator phases and appearance of variable components of electromagnetic torque and consumed power. Such operating modes considerably influence both operation of the motor and operation of the technological mechanism on the whole, as there appears continuous oscillation of motor torque and speed. A possibility of compensation for stator windings asymmetry influence on dynamic and power characteristics of an electric drive with a vector control is demonstrated in the paper. Two structures of induction motor control systems are presented: a system of compensation for electromagnetic torque variable component and a system of compensation for consumed active power variable component. It is shown that the former system provides decrease of electromagnetic torque variable component causing additional vibrations of the motor. The latter system provides decrease of the variable component of consumed active power and thermal overload of motor separate phases.