Modelling and analysis of geared PM stepping motor for simulation of all-electric off-road vehicles

This paper introduces the concept of an all-electric mobile vehicle with independent four-wheel drive configuration which is driven using two-phase geared permanent magnet (PM) stepping motors. These electric motors are referred here as traction motors. The analysis includes a novel design, modelling and investigation of the behaviour of such a motor coupled in series with planetary gearbox for the purpose of vehicle drive on uneven terrains. Lumped-parameter state-space models for torque and angular velocity have been developed for the individual sub-systems to simulate the dynamics of the drive-train system. The investigation in this paper looks into the characteristics of both the traction motor and electromechanical geared motor. An analysis is done on the geared motor model to assure its feasibility for use in an all-electric and/or hybrid vehicle models.