Comparison of 2- and 3-Phase Bearingless Slice Motor Concepts

Several processes in chemical, pharmaceutical, biotechnology and semiconductor industry require contactless levitation and rotation through a hermetically closed process chamber. A highly interesting topology for these applications is the “bearingless slice motor” con-cept, where already some research has been done in the past, especially focusing on topology and implementa-tion issues. However, only little work has been done to evaluate the ideal number of motor phases. In this pa-per, a performance evaluation between 2-phase and 3-phase bearingless slice motor concepts is undertaken. It is shown, that 3-phase systems can supply almost the same power as adequate 2-phase systems and achieve nearly the same acceleration behavior, although they have significantly less complex power electronics.