This paper aims to present a speed sensorless direct field oriented control (DFOC) of an induction motor (IM) fed by current source inverter (CSI). The DFOC is based on the orientation of the rotor flux to be superposed on the d axis of the rotating frame (dq), to achieve similar performances of those of dc motors, hence, the flux is controlled by the d axis current and the torque by the q axis current separately. The stator currents and voltages are employed for the estimation of the rotor flux and its angle and then the calculation of the rotation speed, by means of a sliding mode observer (SMO). Unlike voltage source inverters, a capacitive filter is required at the output of the CSI for current commutation and harmonics filtering, the mathematical model of this filter is used for the prediction and the control of the motor voltages. Simulation results under MATLAB/Simulink have been obtained to verify the effectiveness of the different proposed strategies.

Keywords: Current source inverter (CSI), Direct filed oriented control (DFOC), Model predictive control (MPC)