Effects of Mismatched Parameters in MRAS Sensorless Doubly Fed Induction Machine Drives

This paper deals with a performance analysis of sensorless drives based on doubly fed induction machines. A simplified model of the whole system equipped with a generic MRAS observer is introduced, by taking also into account a mismatch in the parameters. Three MRAS known in literature are analyzed into detail and meaningful analytic relations between the mismatched parameters and the error in the estimated rotor position during a steady state operation are deduced. Then, a stability analysis is performed and the stability regions of each drive are found. Finally, the theoretical results are experimentally validated.