On the self-sensing technique based on the interlink voltage of two serially connected phase coils

Self-sensing magnetic bearings have been investigated for several years. A lot of different methods have been introduced and evaluated. In this work a unique method is considered for implementation in a bearingless slice motor. This self-sensing technique relies on the rotor position dependent interlink voltage of two phase coils which are connected in series and which are energized by a standard switching voltage amplifier. The proposed method is modelled and mathematically described. It has only limited need of additional hardware and is, therefore, relatively easy to implement and integrate in the digital signal processor of the bearingless motor control scheme. To show its practical functionality, the proposed method is implemented in the bearingless flux-switching motor. First measurements show encouraging results.