Design and Analysis of Electrical Braking Torque Limit Trajectory for Regenerative Braking in Electric Vehicles With PMSM Drive Systems

In this project, to improve the regenerative braking of electric vehicles based on a regenerative power analysis, an electrical braking torque limit trajectory is proposed. Even though electric motors generally regenerate electric energy from kinetic energy, the drive system dissipates electric energy under certain low speed operation conditions. 

This phenomenon has been addressed in many previous works and most of them compensate for this power dissipation region by modifying the electrical braking torque limit trajectory of the motor. However, the torque limit trajectory has never been considered based on a regenerative power analysis even though an inaccurate torque limit trajectory causes energy loss to the drive system. 

In this project, the regenerative power analysis for two major kinds of permanent magnet synchronous motor is performed. Afterward, torque limit trajectories are set based on this analysis so that batteries in electric vehicles can harvest the maximum regenerative energy in any circumstance. The proposed system is simulated in MATLAB/SIMULINK.

Keywords: Permanent magnet motors, synchronous motor drives, traction motor drives, regenerative braking, and kinetic energy.