ROBUST TORQUE CONTROL DESIGN FOR INDUCTION-MOTORS - THE MINIMUM ENERGY APPROACH

This paper presents two different aspects concerning the control desig n laws for induction motors: (1) it derives state operating points (st eady-state values for currents and fluxes) parameterized in terms of t he desired motor torque, defining minimum-energy operation conditions for the electrical motor. (2) It gives a state-space feedback control design methodology based on Lyapunov analysis which renders the minimu m-energy operating points invariant. Several controllers are proposed: P-type control, observer-based P-type control, PI-type control and ob server-based PI-type control. The PI-structure and the observer-based control are introduced to deal with motor parameter uncertainties, and the absence of flux measurements, respectively. Stability of all thes e control schemes is studied. Experimental results are also presented. (C) 1997 Elsevier Science Ltd.