A fuzzy-logic-based multimodel field orientation in an indirect FOC of an induction motor

Classical indirect field-oriented control is highly sensitive to uncertainties in the rotor resistance of the induction motor. This sensitivity can be reduced by combining two different methods to compute the stator electrical frequency. Fuzzy logic is used to combine both methods to obtain a compromise which reduces the flux control sensitivity to electrical parameter errors at each operating point. The design of the fuzzy logic block is based on a theoretical sensitivity analysis taking magnetic saturation into account, in simulations and in experiments. In this paper, the performance of the proposed control algorithm is theoretically and experimentally studied. The theoretical predictions are validated by experiments, by considering the stator current variations, to develop a given steady-state torque, induced by the imperfect flux control.