Design Aspects of AMBs for High-Speed Permanent Magnet Synchronous Machine

Distributed power generation is nowadays one of the global trends. Compared with the centralized power gen- eration there is no need to transmit and regulate electricity network in the case of distributed generation. These advantages can be critical for many electricity consumers. Distributed power generation using microturbines is an alternative to the commonly used combustion engines. These installations increase total system efficiency and enable operation at the low partial loads. In this paper the design aspects of a high-speed permanent magnet syn- chronous machine (PMSM) equipped with active magnetic bearings (AMBs) are considered. The structure of the permanent magnet generator is explained and its parameters are presented and discussed. This paper concentrates on the additional magnetic pull created by the PMSM at standstill. This situation creates extra forces and set extra requirements to AMBs. The method to avoid unnecessary magnetic bearing overdimensioning using electrical machine control system is described. An influence of the unbalanced magnetic pull on the active magnetic bearing control is presented. The uneven distribution of the force leads to additional complexity for the controller synthesis. The rotating reference frame for the control problem formulation is discussed.