Eigenvalue-based relative parameter sensitivity analysis for optimised performance of sensorless induction motor drives

The formulation of a suitable control scheme for induction motor (IM) drive capable of working in a wide speed range including low and zero speed regions is a challenging task as the system parameters are prone to vary significantly due to temperature rise, skin effect and associated factors. The present study proposes eigenvalue sensitivity-based generalised analytic approach for identifying the dominant motor parameter(s) which affect(s) the estimated speed most severely in the speed sensorless IM drive system. Once such parameter(s) is/are identified, a compensation scheme can be adopted for the same without worrying to the effect of the other motor parameters on the estimated speed. This not only reduce(s) the drive's complexity but also improves the reliability of the overall system. To validate the proposed approach, two different model reference adaptive systems are considered for the speed sensorless IM drive. All the relevant study is done in MATLAB/Simulink. The experimental results as obtained by a dSPACE-1104-based laboratory prototype also justify the analysis.