ABSTRACT A comparative thermal performance study is carried out on an induction machine (IM) and an interior permanent magnet synchronous machine (i‐PMSM) for electric vehicle applications under the standardized Highway Fuel Economy Test (HWFET) and Worldwide Harmonized Light Vehicles Test Procedure (WLTP) Class 3 drive cycles, using ANSYS Motor‐CAD in this paper. To allow a fair comparison of steady state and transient thermal behavior, identical cooling boundary conditions were set while considering a consistent electromagnetic thermal modeling framework. The results show that i‐PMSM has lower total losses (2.265 kW) than the IM (3.37 kW) under representative drive cycle operating conditions, since there are no rotor copper losses involved. In the case of operation during WLTP Class 3, peak stator winding temperatures reached 173.3°C and 133.6°C for the IM and i‐PMSM, respectively, with substantially larger thermal stresses in the IM. From this, it can be seen that the transient thermal response exhibited by i‐PMSM was much smoother, with reduced temperature oscillations under dynamic loading, whereas the thermal fluctuation of the IM was significant during frequent acceleration and deceleration events. Although peak efficiency regions above 97% have been observed in both machines at specific torque–speed combinations, drive‐cycle‐integrated loss behavior has shown that i‐PMSM maintains lower overall thermal burden across the investigated operating conditions. These findings consequently bring to the fore the importance of drive cycle dependent thermal evaluation in electric vehicle motor selection and reveal that while the IM has strong benefits regarding robustness and cost, i‐PMSM will have superior thermal efficiency and stability during realistic driving scenarios. The presented comparative framework offers practical insights into traction motor design and technology selection in electric vehicle applications.
Prasanna et al. (Sun,) studied this question.