A PI-Fuzzy controller designated for industrial motor control applications

Variable speed drives are nowadays growing and varying very fast. Drives expanse depends on progress in different part of science like power system, electronic, control methods and so on. Because the fuzzy logic techniques can be used to control any type of system without requirement of the system mathematical model it started to be used in electrical drive controllers. Industrial controllers based on fuzzy control has emerged during the last years as one of the most active areas of research in the applications of fuzzy set theory. The industrial processes, usually do not lend themselves to control by conventional methods because of a lack of quantitative data that are describing the plant input-output relations. Under various external influences as variation of electrical parameters, inertia or friction forces most of the conventional controller fails to fulfill the control demands. This happens due the mathematical background and initial assumptions on which the conventional methods relies on. On the other hand the fuzzy control is based on fuzzy logic, a logical system that is much closer to the human thinking and natural language compared with the classical control methods. Usually the synthesis of an industrial controller includes both the controller type selection and the adjustment of its parameters. In some cases the controllerpsilas type might be more complex than a PI(D) type controller. In all the cases, the tuning problem must be satisfactorily solved. These type of situations can be solved more easily with a fuzzy controller which has made possible the establishment of intelligent control. However, the controller based on fuzzy logic theory are used only in simple configurations and their analytical knowledge is still poor. In this paper, a quantitative and qualitative study of fuzzy controller is made.