Discrete adaptive speed sensorless drive of induction motors

The use of mechanical speed sensor in the field of control of induction motors can cause some problems. Recently, many software are developed to estimate the speed by using only electrical measurements and machine parameters. This paper presents a new speed sensorless drive of induction motors for field oriented control. The proposed speed estimator is based on the Model Reference Adaptive Scheme (MRAS) and uses based the comparison of estimated and measured stator current. The reduction error is achieved by at appropriate unity transfer function as reference model. The estimator formulation is defined and developed in the discrete case. The proposed algorithm requires neither matrix calculation nor approximation on Taylor series of matrix exponential. To establish the stability of the discrete estimator, the hyperstability concept introduced by Popov in the discrete case is used The influence of the sampling period on the algorithm stability of is studied Some simulation results are presented, in order to valid the theoretical development. Copyright (C) 2007 Praise Worthy Prize S.r.l. - All rights reserved.