Concept of Integration of Axial-Flow Compression Into Electric Machine Design

The purpose of this paper is to propose a novel concept of a high-speed electric machine system with integrated airfoil-shaped rotor designed to perform axial-flow compression for vehicle applications. The proposed high-speed machine is both a motor for electromagnetic (EM) energy conversion and an axial flow compressor for thermodynamic energy conversion. Conventional designs usually have a separate motor and compressor that are connected through a common shaft with or without a gearbox. The proposed design simplifies the high-speed machine and compressor system by eliminating the components that connect the motor and the compressor. The integrated motor-compressor design can achieve a more compact system. The flux-switching permanent magnet (FSPM) machine is chosen out of several possible electric machine topologies with salient rotor pole features for the integrated motor design. The feasibility of this integrated motor-compressor design is discussed from both the EM and thermodynamic perspectives in this paper. The selection of slot/pole combination and EM sizing equations for the integrated FSPM motor-compressor are discussed. Mean-line design equations for the axial flow compressor are studied for the proposed integrated motor-compressor. The EM torque production capability of the proposed integrated motor-compressor is verified for one possible design in this paper by finite element analysis (FEA). The effects of two different attack angles of the rotor blades are studied compared to the conventional FSPM machine. The FEA results show that the proposed integrated motor-compressor achieves the expected output performances.