Comparative Evaluation of MTPA Control Strategies for Permanent Magnet Synchronous Motors in Electric Vehicle Applications

This paper presents a comparative study of analytical Maximum Torque per Ampere (MTPA) control strategies for Permanent Magnet Synchronous Motors (PMSMs), which are widely used in electric vehicle (EV) traction systems due to their high efficiency and torque density. The MTPA control objective is to maximize torque output while minimizing stator current, thereby reducing copper losses and enhancing energy efficiency. Three analytical MTPA strategies were implemented within a Field-Oriented Control (FOC) framework and compared to the conventional i<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d0</inf> method. These methods differ in how the optimal current references are computed-via current magnitude, optimal current angle, or hybrid approaches. Simulations under nominal operating conditions evaluated torque ripple, RMS current, and dynamic response. All MTPA methods outperformed the i<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d0</inf> baseline: the Classical Analytical Method achieved the fastest transient response, Current Reference-Based Method resulted in the lowest RMS current, and the Optimal Current Angle Method provided the best overall trade-off between stability and efficiency. Although performance gains were moderate due to the motor's low saliency, results confirm the effectiveness of analytical MTPA strategies in improving drive performance and support their integration in future high-efficiency EV propulsion systems.