Robust Shaping Indirect Field Oriented Control for Induction Motor

Over the past years, thanks to the systematic use of digital microprocessors in industry, we have seen a very significant development in the regulation controls of the asynchronous machine. The latter is widely used in industry for its diversity of use and its ability to withstand great variations in its nominal regime. Currently, several types of control are proposed. Nonlinear controls such as linearization input-output (Benchaib & Edwards, 2000) (Chan et al., 1990) (De Luca & Ulivi, 1989) (Marina & Valigi, 1991), the controls resulting from the theory of passivity (Nicklasson et al., 1997) (Gokdere, 1996) which generally require the measurement of all system states (currents and flux). As the flux of the motor cannot be measured, a great part of the literature is devoted to the control problem coupled with a nonlinear flux observer (Kanellakopoulos et al., 1992). Other controls using only the exit returns (rotor speed and stator currents) were developed resulting in controls of the passive type (Abdel Fattah & Loparo, 2003), other controls using the technique of backstepping or the techniques derived from the orientation of the flux field (Peresada et al., 1999) (Barambones et al., 2003). The parameters of such controls must be selected in order to ensure total stability for a given nominal running and nominal values of the parameters. Thus, different robust controls with parameter uncertainties, such as the discontinuous or adaptive controls, were developed (Marina et al., 1998). These techniques adapt the controls to the variations of resistances and the load couple. A control which is very common in industry is the indirect field oriented control (FOC) based on the orientation of the field of rotor flux. This control allows the decoupling of speed and flux, and we obtain linear differential equations similar to the D.C. machine. The regulation is carried out finally by simple controller PI (cf Fig. 1). However, the decoupling observed is only asymptotic. The behaviour of the transient regime and the total stability of the system remain a major problem. In addition, the modifications of parameters such as rotor resistance or resistive torque deteriorate the quality of decoupling. In this paper, we propose a diagram of  H regulation, linked to the field oriented control allowing a correct transient regime and good robustness against parameter variation to be 4