Control of induction machine with extended range of maximum torque capbility for traction drives

In this paper, a novel control scheme of an induction machine for 48V- battery based traction drive system is presented. The main features of the proposed control scheme are the capability to boost the maximum torque capability over the entire speed range by an optimized over-modulation strategy and smoothly transition the maximum torque-per-ampere to field weakening region despite significant variations of the source voltage and machine parameters. The nonlinear saturation effect of the mutual inductance is taken into account to produce the limitation curves thus to reach the actual maximum torque over the whole speed range. Experimental results show that the proposed control scheme is most suitable for low-voltage 48V- battery traction drive systems.