Design of a novel multi-drive system with reduced torque pulsations for an electric vehicle

The novel drive presented in this paper makes use of two specially designed permanent magnet axial field disc motors for each of the rear wheels of an electric vehicle. The stators of the two motors are mounted onto the chassis of the car, whilst the rotors are coupled to the shaft and directly drive the road wheel. Hence a reduction in the un-sprung mass of the wheel drive can be achieved. However since the wheel is perturbed by the road surface roughness effects, the rotor will move between the stators and induce torque pulsations in the machine. The new motor drive results in significantly reduced torque pulsations as compared with the case when a conventional disc motor is used. The paper presents design of the novel drive and 2D finite element analysis results