Natural variable simulation of induction machines

A method for obtaining natural variable model of induction machines (IM) is presented. The variables of the model are electromagnetic torque (T_e), reactive torque (T_r), magnitude of rotor flux linkage (lambda_r), magnitude of stator flux linkage (lambda_s), and rotor speed (omega_r). These variables do not change in any reference frame of transformation. The model obtained is expressed in a state-space form with the natural variables as state variables. Simulation is carried out and the results are compared with a conventional induction machine simulation technique. Simulation results show the efficacy of this model in predicting electrical behavior of induction machines. Flux linkage orientation is done to facilitate the simulation, which is similar to method of alignment in vector control.