A flux observer for induction machines based on a time-variant discrete model

The authors present an approach to obtain a discrete-time counterpart of the two-axis continuous model of an induction machine. The discrete time-variant equations are derived from a partial discretization of the continuous state equation. A discrete time-variant reduced order flux observer is then proposed by using the discrete model. Computer simulation results show better performance of the proposed model in terms of accuracy and stability compared with those obtained from the classical Euler method. Although apparently complex in its formulation, only sums of 2×2 matrices and repetitive scalar multiplications are required