Sliding mode observer for mono-inverter bi-motors railway traction system

The aim of this work is to study sliding mode observer applied to mono-inverter bi-motors system for railway traction application. Studied system composed of two induction motors (IM) fed by one voltage source inverter (VSI) which controlled by Mean Rotor Field Oriented Control (MRFOC). Both IM are coupled through common loads which complicate this study and introduce perturbations of all system; this mechanical coupling was modelled and integrated on the traction system. The MRFOC needs reconstitution of mean rotor flux that can be obtained by one observer through the average of both motor currents and speeds. Also, we can apply two observers, one of each IM, and the mean rotor flux observed is obtained by the average of both rotor fluxes observed. These observers are based on sliding mode method. Some simulations are offered to compare two observer strategies in normal and distributed functioning.