A New Formulation of Reactive-Power-Based Model Reference Adaptive System for Sensorless Induction Motor Drive

Various functional candidates such as flux, back electromotive force, and reactive power are used to form a model reference adaptive system (MRAS) to estimate the speed of an induction motor drive. Of these, reactive power (Q) based controllers perform well at low speeds and are inherently independent of stator resistance. However, such configuration fails to provide stability in the regenerative mode. This paper proposes a new formulation of reactive-power-based MRAS that is stable in all the four quadrants of operation. A detailed MATLAB/Simulink based simulation study is presented. Superior performance of the proposed controller is confirmed by prototype experimentation using a field-programmable-gate-array based controller in the laboratory.