State Space-Vector Model of Linear Induction Motors

This paper presents the state space-vector dynamic model of the linear induction motor (LIM) taking into consideration the dynamic end effects. Starting from the space-vector equivalent circuit of the LIM, the complete set of space-vector equations has been deduced. Afterward, first the so-called voltage and current flux models have been written, from which the complete state space-vector representation has been given. The complete thrust expression including the end-effect braking force has also been introduced in the model. The complete state space-vector model, electromagnetic and mechanical part, has been implemented in numerical simulation and has been validated by comparing the results with those obtainable with a finite-element analysis and experiments. Results show that, even with a machine with a limited presence of the dynamic end effects, the adoption of a this model permits a better estimation of both the electric quantities, e.g., inductor current, and the mechanical quantities, e.g., linear speed, with respect to the classic rotating induction motor model.