The effects of internal and external disturbances for the hybrid fuzzy-fuzzy controller applied to IM-drive

This research represents a study of the effects of internal and external disturbances for the developed hybrid fuzzy-fuzzy controller (HFFC) scheme to gain control over the speed of an induction motor´s (IM) variable speed drive (VSD). In case of an induction motor, the fuzzy current amplitude control and fuzzy frequency control are observed in a closed-loop current amplitude input model. A hybrid controller is formed by a combination of both controllers. In order to overcome a drawback of field oriented control (FOC) method, the principle of HFFC is based on a rule to control a speed of a rotor by utilizing a fuzzy frequency controller during the accelerate-decelerate stage. Whereas, a fuzzy stator current magnitude controller is used during a steady-state stage. The two aspects (current and frequency) of FOC are engaged to design a scalar controller. To observe a performance of a controller, a simulation is carried out by means of software, MATLAB/Simulink. Hence, a performance of a controller is observed by conducting a series of tests, and it has been concluded that a controller is more reliable and shows an insensitive behavior towards the parameter variation in the system and motor robustness to load and noise disturbances.