Fuzzy Logic Techniques Applied to the Control of a Three-Phase Induction Motor

Until not long ago, most fuzzy logic based control applications were limited to the management of user interfaces, sensors and actuators, corresponding to a slow software operation. These techniques are specially appropriated whenever the system model is non-linear and/or difficult to obtain. Is it viable to use fuzzy logic in faster “real time” applications? Is it interesting to use these techniques even when the system model is known (including linear cases)? We are trying to answer some of these questions applying fuzzy logic to control electrical machines. In this paper we use a slip control scheme for a three-phase induction motor fed by a voltage-source PWM inverter as an example. The evaluation of the fuzzy logic controller behaviour is made through the comparison with a traditional technique (PI controller with antiwindup mechanism), using computer simulations (performed with Matlab/Simulink) and experimental results. Implementation was made using the fuzzyTECH software tool to design the fuzzy logic controller and to produce C-code for an Intel 80C196KC microcontroller. An 1 kW threephase induction motor fed by a voltage source IGBT power module was used in the experiments.