Advanced Structures of Modern Electrical Machines for Electric Transportation

This paper presents a review of the development and structural classification of modern electrical machines employed for electric transportation. It highlights the back-EMF characteristics and excitation techniques of various machines by classifying them according to the placement of the Permanent Magnets (PMs) and the type of stator winding. This also includes Hybrid PM Machines (HPMM) where the magnets are magnetized in the same direction. With an emphasis on thermal issues, demagnetization, and manufacturing issues, the study particularly reviews stator-PM machines and presents a novel Doubly Salient Parallel Path Magnetic Motor (DS-PPMM) which offers reduced cogging torque, less torque ripple, and more sinusoidal back-EMF waveform in comparison with other doubly salient concentrated wound machines.