MATHEMATICAL MODEL AND COMPUTATIONAL ANALYSIS OF SELECTED TRANSIENT STATES OF CYLINDRICAL LINEAR INDUCTION MOTOR FED VIA FREQUENCY CONVERTER

The mathematical model of cylindrical linear induction motor (C-LIM) fed via frequency converter is presented in the paper. The model was developed in order to analyze numerically the transient states. Problems concerning dynamics of ac-machines especially linear induction motor are presented in [1 - 7]. Development of C-LIM mathematical model is based on circuit method and analogy to rotary induction motor. The analogy between both: (a) stator and rotor windings of rotary induction motor and (b) winding of primary part of C-LIM (inductor) and closed current circuits in external secondary part of C-LIM (race) is taken into consideration. The equations of C-LIM mathematical model are presented as matrix together with equations expressing each vector separately. A computational analysis of selected transient states of C-LIM fed via frequency converter is presented in the paper. Two typical examples of C-LIM operation are considered for the analysis: (a) starting the motor at various static loads and various synchronous velocities and (b) reverse of the motor at the same operation conditions. Results of simulation are presented as transient responses including transient electromagnetic force, transient linear velocity and transient phase current.