Comparative experimental assessment for high-performance sensorless induction motor drives

This paper compares the experimental performance of three flux and speed observers for speed-sensorless induction motor drives. The three methods are generally accepted to be leading candidates for high sensorless performance: rotor-flux MRAS, torque-current MRAS and the adaptive nonlinear flux observer. The paper discusses baseline conditions for the tests: these include matched load inertia, specified speed estimator dynamics and sensorless operation within a speed control loop. For the comparison tests in the paper, the speed estimation dynamics of the methods are approximately the same; this is important for parameter sensitivity. The paper concentrates on tests for zero and low speed performance and all results shown are under sensorless speed control. It is hoped that the tests undertaken can become benchmark tests for sensorless induction motor drives