An Improved Rotor Flux Space Vector Based MRAS for Field-Oriented Control of Induction Motor Drives

The paper proposes an improved low speed performance of classical rotor flux (RF)-based model reference adaptive system (MRAS) for field oriented controlled induction motor (IM) drives. The improved performance of the RF-MRAS estimator is obtained by using voltage reference vector to compute the rotor flux vector in the reference model instead of actual voltage signal vector in the process of speed estimation. The voltage reference vector is estimated by using proportional integral controller over the error signal vectors obtained from the difference between the reference and the measured current vectors. This modification allows satisfactory low or zero speed estimation of IM drive using RF-MRAS-based estimator. The proposed drive's performance is compared with classical RF-MRAS and its performance for the low-speed operation is also authenticated with (V) over right arrow* x (I) over right arrow based MRAS inMATLAB/Simulink. Stability and sensitivity studies are further carried out to ensure the robustness of the drive system. Experimental results as obtained by a dSPACE-1104 based IM laboratory prototype are also presented to validate the simulation study.