Interior permanent-magnet synchronous machines (IPMSMs) are widely used as traction motors in electric drive-trains because of their high torque-per-ampere characteristics and potential for wide field-weakening operations to expand the constant-power range. This paper offers a categorization and a comprehensive overview of the control techniques applied to IPMSM drives in addition to presenting the necessary theoretical background. The basic concept, features and limitations, as well as the latest developments of the strategies, are summarized in the paper. This overview helps to lay the theoretical basis as well as to clarify the opportunities, challenges and future trends for controlling IPMSM drives for traction applications.

Interior permanent magnet synchronous machines (IPMSMs) are widely used as traction motors in the electric drive-train because of their high torque-per-ampere characteristics and potential for wide field weakening operation to expand the constant power range. The paper aims to introduce the most important equations to calculate the operating trajectories of an IPMSM for optimal control. The main contribution is that the optimal operating trajectories are calculated by a feedforward, Newton–Raphson method-based searching algorithm that considers the iron loss resistance of IPMSMs. Steady-state calculations and dynamic simulation results prove the theoretical findings.