Most of the industrials motors are used today are in fact induction motors. Induction motors have been used in the past mainly in applications requiring a constant speed because conventional methods of their speed control have either been expensive or highly inefficient. Various methods have been designed to achieve the best performance of the motor and the approaches used can be classified into three different types. The first, so called "loss model controller" (LMC). The second type, named "search controller" (SC). The third one uses "look up tables".