Speed Sensorless Vector Controlled Induction Motor Drive Using Single Current Sensor

New speed and current estimation techniques are proposed in this paper. These are used to formulate a single current sensor-based vector controlled drive. The speed sensorless control is formulated by developing a new model reference adaptive system (MRAS) using the outer product of →vs
^*
and →is as the functional candidate. Contrary to the method available that depends on stator resistance, the proposed approach is immune to the variation of stator resistance. This is possible by using reference quantities (i.e., voltage and currents) in reference model and actual quantities (i.e., currents) in adjustable model. The current estimation on the other side extracts the information of the phase currents in two-phase stationary reference frame by using the corresponding synchronous reference frame variables and the vector rotator. The current estimation also does not depend on stator resistance and hence the complete system can perform very well at low speed. The proposed speed and current estimation techniques are simulated in MATLAB/Simulink and experimentally validated through a dSPACE-1104-based laboratory prototype.