H∞ Controller Design for Induction Motor to Attenuate Rotor Resistance Perturbation and Torque Disturbance with Field Oriented

It is well known that the system performance of field oriented control induction motor drives degrades under the variation of rotor resistance and in the presence of external load torque disturbance. H _infin state feedback method is employed to design controller for induction motor fed by a current controlled voltage source inverter in this paper. The proposed control law can achieve convergence to zero of both speed and flux tracking errors and ensure robustness with respect to torque disturbance and rotor resistance variation. In some sense, the proposed controller can be regarded as a PI controller by studying its structure, from the H_infin, point of view, this result explains why PI controllers have been used successfully in field oriented control partially. Another important contribution of this result is that it presents a useful way to design robust PI controller. Simulation results are given to validate the proposed method