Direct field oriented control of linear induction motors

This paper deals with direct field oriented control of linear induction motor drives. After elaborating the inductor and induced part space-vector equations of the LIM in several reference frames, some induced part flux models taking into consideration the end effects are presented. In particular, the so called "voltage model" based on the inductor equations in the inductor reference frame and the "current model" based on induced part equations in both the inductor and induced part flux linkage reference frames are deduced and compared to the rotational induction machine counterpart. Afterwards, after a proper tuning of such models based on both FEA (finite element analysis) and experimental measurements, some simulation and experimental tests have been performed. Simulations show that the proposed flux models taking into consideration the LIM end effects permit the drive to achieve better dynamic performance. Moreover, some comparative experimental results, adopting both the current and the voltage flux models, have been performed on a suitably devised test set-up.