Improvement of induction motor performance at low speeds using fuzzy logic adaptation mechanism based sensorless direct field oriented control and fuzzy logic controllers (FDFOC)

This paper presents a more relevant infrastructure: fuzzy sensorless direct field oriented control (FDFOC), compared to the usual sensorless direct field oriented control (DFOC), in order to improve the induction motor (IM) performance at low speeds. In the FDFOC, a fuzzy logic adaptation mechanism based Luenberger observer used for speed adaptation is adopted, and all the proportional-integral (PI) controllers are substituted for intelligent ones: fuzzy logic controllers (FLCs). In the interest of evaluating both systems performance FDFOC and DFOC, a detailed comparative study is presented: functioning in both motor rotation directions with application of load torque disturbance at low speeds. Simulation tests prove the robustness of the new infrastructure FDFOC in comparison with the usual DFOC: Quick response, good load torque rejection, decrease of the stator phase current on startup, as a result the system dynamic has been improved significantly. On the other hand, the simulation presents excellent speed observation using adaptive Luenberger observer (ALO) whereas the estimated speed perfectly pursues the reference at low speeds. Simulations are done using Matlab.