Effect of stator leakage inductance in field weakening region of a vector controlled induction machine drive for traction application

The vector controlled induction machine drive with field weakening capability is a preferred choice for traction applications. The parameters of the machine have a significant influence on the performance of the drive. The maximum torque output in the field weakening region is limited by the leakage inductances of the machine. Therefore, while selecting a machine for a traction application, it must be ensured that the leakages are such that the required torque speed characteristics are well satisfied in the field weakening region up to the maximum speed. This paper analyses the effect of leakage inductance on the performance of the induction machine drive in the field weakening region. The critical value of leakage inductance which ensures operation up to the highest application speed with specified load demand is derived. The effect of leakage inductance in field weakening region is studied using Matlab/Simulink. The field weakening algorithm is experimentally validated on a 30 kW induction machine, up to five times the base speed.