A fuzzy controller for an axial magnetic bearing

The use of magnetic bearings is very promising. The absence of mechanical friction and any type of contamination are some characteristics that justify their application in different industrial activities. To dominate this technology is necessary the study of diverse fields of electric engineering such as: electromagnetism, control, electrical machines, analog and digital systems and power electronics. Sophisticated techniques are necessary for the control of a magnetic bearing, because there are electrical non-linear relationship between the airgap and the current. In this work the fuzzy logic approach was use to design the controller. This technique allows the constructing of a control system based in a group of rules in a similar way as the human thought does. The use of this logic is justified in systems whose dynamic behavior is not well known. These rules were based on experimental results of a derivative proportional controller (PD) previously implemented and then tested through computer simulations. In order to compare theoretical results with experimental values, a test workbench was constructed. These results will be presented in this work.