A nonlinear H-infinity feedback control approach for asynchronous generators

A new method for feedback control of asynchronous electrical machines is introduced, with application example the problem of doubly-fed induction generators (DFIGs). The control method consists of a repetitive solution of an H-infinity control problem for the DFIG, that makes use of a locally linearized model of the generator and takes place at each iteration of the control algorithm. The asynchronous generators model is locally linearized round its current operating point through the computation of the associated Jacobian matrices. Using the linearized model of the generator an H-infinity feedback control law is computed. The known robustness features of H-infinity control enable to compensate for the errors of the approximate linearization, as well as to eliminate the effects of external perturbations. The efficiency of the proposed control scheme is shown analytically and is confirmed through simulation experiments.