Three Practical Examples of Magnetic Bearing Control Design Using a Modern Tool

Abstract

The use of magnetic bearing in industrial applications has increased due to their unique properties. Nowadays efficiency and predictability in handling rotors on magnetic bearings is asked with the same standard as conventional rotors on oil or roller bearings. First of all one must be aware of the special technical properties of magnetic bearing designs. The dynamic behavior of the rotor combined with requirements of the application define the desired bearing characteristic. With modern tools covering the mechanical aspects as well as the electronic controllers and their digital implementation on a DSP, these properties can be designed. However, despite the use of such efficient tools engineering practice is needed. Therefore this paper summarizes the major steps in the control design process of industrial applications. Three rotors supported on magnetic bearing with their specific dynamic behavior are presented: a very small high speed spindle (120,000 rpm); a small industrial turbo molecular pump rotor (36,000 rpm); and a large multistage centrifugal compressor (600 to 6300 rmp). The results of the analyses and their experimental verification are given.