Ac motor drives are used in a multitude of industrial and process applicationsrequiring high performances. In high-performance drive systems, the motorspeed should closely follow a specified reference trajectory regardless of anyload disturbances. The motor-control issues are traditionally handled by fixed-gain proportional-integral (PI) and proportional-integral-derivative (PlO)controllers. However, the fixed gain controllers are very sensitive to loaddisturbances. In order to overcome this problem, the fuzzy-logic controller(FLC) has been recently used for motor control purpose. The mathematical toollor the FLC is the fuzzy set theory introduced by Zadeh. It is based on thelinguistic rules with an IF-THEN general structure, which is the basis of human,logic. However, the application of FLC has faced some shortcomes duringhardware and software implementation due to its computational burden.Some calculation programs have been developed to determine thevoltage and frequency which should be applied to the motor to enable it to runat constant speed with variable loads, or variable speeds with constant load, orvariable loads, with variable speeds. The outputs of these programs are fed tothe Sugeno-type fuzzy inference to estimate its output (voltage or frequency orboth) if it is excited by its inputs (torque or speed or both).Two models has been designed to perform the closed-loop fuzzycontroller system for inverter fed three phase induction motors. The model isdistinguished according to the inputs of the fuzzy logic controller.The speed error (Aro) and the rate of change of speed error (~ffi/~t) areconsidered as the input linguistic variables and the motor frequency ISconsidered as the output linguistic variable for the first model. Two differenttechniques were developed to accomplish this model. In the first technique, the