INDUCTION MOTOR CONTROLLER

摘要

PURPOSE:To control the rotational speed of induction motor stably at all times without causing deficiency of torque or overcurrent and regardless of the variation rate of primary frequency command or a machine driven through the induction motor. CONSTITUTION:A noload voltage operating circuit 5 outputs the noload voltage of an induction motor 1. An error current component operating circuit 6 outputs an error current component which goes zero when the actual value of primary flux induced in the induction motor matches with a command value of primary flux determined by the product of an exciting current value and the primary self inductance of the induction motor. A correction voltage operating circuit 7 outputs a correction voltage for bringing the error current component close to zero. A primary voltage command operating circuit 8 outputs a primary voltage command value of the induction motor. A variable frequency power converting circuit controls the actual value of the primary voltage to be applied on the induction motor so that it follows up the primary voltage command value.