Study on the Harmonic Loss of Permanent Magnet Toroidal Space Motor for Hybrid Electric Vehicles

Based on magnetic gear transmission principle, permanent magnet toroidal space motor for hybrid electric vehicles with dual-rotor drive is proposed in this paper, harmonic loss caused by toroidal space relative motion of two rotors is conducted in hybrid drive mode. According to the structural principle of toroidal space motor, the speed of permanent magnet teeth of planet and worm inner rotor are decomposed to the revolution and rotation planes respectively. On the two planes, the frequency of alternating magnetic field at toroidal stator, planet and worm inner rotor are derived. At iron core and permanent magnetic teeth of stator and rotor, the magnetic field of revolution and rotation components are simulated. Combining with the speed relationship of toroidal space motor, the harmonic losses of revolution component and rotation component are analyzed in hybrid drive mode. The influence of speed matching of two rotors and toroidal stator material on harmonic loss are discussed. The results indicate that harmonic loss of permanent magnet toroidal space motor for hybrid electric vehicles can be reduced effectively by reducing relative speed of two rotors and adopting amorphous alloy for toroidal stator.