Integrated electromechanical modeling of electric powertrains considering dynamic load inertia and time-varying torque characteristics

Load inertia and load torque are critical parameters influencing the dynamic performance of electric powertrains, directly affecting stability, energy efficiency, and safety. Traditional models often treat load inertia as a disturbance and ignore the time-varying characteristics of load torque, limiting applicability. This paper proposes an electromechanical integrated modeling approach that incorporates dynamic variation of load inertia and time-varying characteristics of load torque. First, the architecture of the electric powertrain is presented, and a two-inertia-system-based electromechanical modeling framework is described according to its operational characteristics. Then, a field-oriented control strategy combining maximum torque per ampere and flux-weakening control is integrated to form the system model. Next, a vehicle dynamics model is introduced to capture the effects of time-varying load torque. Load inertia is dynamically computed using the kinetic energy theorem to capture coupling among environmental, mechanical, and electronic factors. Finally, dynamic responses of speed, current, and torque are analyzed through multi-scenario simulations under varying inertia and torque conditions. The findings indicate that the proposed method effectively captures time-varying characteristics, significantly enhancing dynamic performance evaluation. This research offers new modeling insights and technical pathways for accurate prediction and optimization of electric vehicle dynamic performance.