Synthesizing the Optimal Control of an Induction Motor-Based Traction Electric Drive with Taking into Account Magnetic Saturation and Core Losses

Abstract

Traction electric drives based on an induction motor often employ vector control with orienting along the rotor flux vector, with which it becomes possible to achieve high performance indicators of the motor and drive as a whole in both static and dynamic operation modes. However, to achieve high energy efficiency of the drive, the use of optimal control strategies becomes of issue. This implies the need to set up, given a specified electromagnetic torque, the stator current flux-forming and torque-forming components according to a certain law to achieve the motor operation optimized with respect to the selected criterion. In the context of a traction electric drive, such criteria are stator current to be maximized or power losses to be minimized. In doing so, it is important to take into account the motor magnetic system saturation and core losses, which have a significant impact on the synthesis of optimal control strategies. The article gives the equations of electromagnetic processes in a cage induction motor with field-oriented control and with taking into account the above-mentioned specific features. A procedure for synthesizing optimal control strategies while minimizing power losses and stator current is also given. Differences in approaches to the synthesis of optimal strategies with and without taking the magnetic system saturation into account are shown.