Development of Virtual Methodology to Evaluate Electric Motor Losses

Electric motors represent one of the most efficient and performant devices to convert electrochemical energy into mechanical energy. The permanent magnet synchronous machines (PMSMs) are the most commonly employed solutions for electric propulsion in the automotive field, thanks to their high torque capability and high efficiency, compared to other solutions as the induction machines. Nevertheless, reducing the losses in electric motors is one of the major targets in the automotive industry and to model them, the major tool employed is finite element analysis (FEA). The scope of this research activity is to accurately model and predict the electric motor losses and efficiency, exploiting the case study of the internal permanent magnet employed in the Fiat 500 battery electric vehicle (BEV). An estimation method is provided for each of the motor losses, namely joule, core and mechanical losses, prior to running the simulations. The motor is implemented into two software environments and its behavior simulated. The outcomes of the simulation are provided to a code developed in MATLAB™ to assess the losses and the efficiency for each operative point and then allocate the results into maps. Afterwards, the simulation results are compared to the experimental behavior. Lastly, some considerations about the motor model implementation, loss models development and efficiency map evaluation are presented.