Design and loss analysis of a new self-decelerating PM in-wheel motor

This paper proposed a new self-decelerating PM in-wheel motor (SDPMIWM) which replaces the stationary ring of the conventional magnetic-geared motor with the stator teeth and is magnetized in Halbach Array. Unlike the traditional PM synchronous motors, the SDPMIWM operates on the harmonics. The field is full of harmonic components and the flux waveforms in the motor can be complex. All these makes calculating the motor loss difficult. Thus, this paper study the field distribution of the motor, including harmonic analysis, magnetization in key positions of stator and rotor, and end effect in the motor including its influence in motor's performances. Then, the hysteresis and eddy current loss in stator and rotor are analyzed. Furthermore, the eddy current loss in the PMs is also investigated and the potential over-heating points are specified, making contributions to motor optimization. Besides, the radial magnetized motor with the same structure as the SDPMIWM is also analyzed to verify the advantages of the Halbach Array in improving the strength of magnetic field and the quality of flux waveforms, and in reducing end effect's influence in motor's performances.