A new PM-assisted synchronous reluctance motor with 3-D trench air gap

This paper proposes a new 3-D motor with a trench-shaped air gap. The proposed motor has high torque without rare earth magnets compared to conventional 2-D single air gap motors due to its multiple air gap and ferrite permanent magnet (PM) assisted segment rotor poles. First, the practical design is described of the winding and side stator core composition, which increase air gap area. Second, the reduction method of eddy current loss in the side stator core is described. Lastly, it is confirmed by FEA and some experimental data that the motor efficiency is improved without reducing torque output.