A new fault-tolerant switched flux machine with hybrid permanent magnets

This paper put forward a new fault-tolerant hybrid switched-flux PM (HSFPM) machine design employing the synergy of NdFeB and Ferrite Magnet. The key of the proposed HSFPM designed machine is the unique design E-core laminated stator with the hybrid magnet to ensure a drastic reduction of NdFeB magnet without compromising the output performances and efficiency in the conventional SFPM machine design to avert the huge demand of NdFeB and its associated volatile high price increase. Additionally, the fault-tolerant stator teeth designed principle implemented in the proposed HSFPM machine provides enhanced segregation among the various phases and ensures continuity of operation with acceptable operating performance under fault-condition. For fair evaluation and comparison, both the proposed HSFPM and the conventional SFPM (CSFPM) machine have the same slot-pole combination, winding arrangements, and stator/rotor dimensions except for the unique outer-stator of the proposed design. Meanwhile, compared to the CSFPM machine, the proposed HSFPM machine design makes use of only 60% of the PM (NdFeB) length. Finally, the evaluation of the no-load in conjunction with the load condition performances was carefully investigated by the Finite Element Method (FEM) of the ANSYS Maxwell software. The results depicted that the proposed HSFPM exhibits similar sinusoidal back electromotive force, comparable output torque, and slightly higher efficiency compared to that of the CSFPM machine.