Steady-State Features of DFIM in Electrical Traction Systems

This paper explores the potential integration of Doubly-Fed Induction Machines (DFIM) into a variable speed traction system by investigating the DFIM’s steady-state features and performances. The equivalent circuit is an indispensable tool for analyzing the steady-state characteristics of DFIM. Nevertheless, the existing steady-state model does not accurately analyze some special operation modes. To overcome the limitation, in this article, a complete DFIM drive model is developed under MATLAB environment using d-q dynamic model to verify the strength and significance of the proposed controller. Based on the synchronized mathematical model, analytic determination of the control laws is presented and illustrated by various figures to understand the effect of the applied rotor voltage on the torque and the efficiency. The motor performances with proposed rotor voltage control are compared to conventional asynchronous motor. This study shows that by combining the synchronous and asynchronous torques, the DFIM electromagnetic torque can be increased across a wide range of speeds and overload capabilities can be improved. This is an attractive and valuable feature for electric vehicle applications.