Impact of Gear Ratios on Drive Cycle Efficiency and Thermal Performance in Lightweight EV S

ABSTRACT This study investigates the performance and thermal behavior of induction motors used in electric vehicles under different gear ratios. In line with increasing energy efficiency requirements, the dynamic characteristics of the motor during the WLTP Class 1 driving cycle have been analyzed in detail. A four‐pole, squirrel‐cage induction motor with a rated power of 5 kW was designed, and its electromagnetic performance and loss components have been calculated using ANSYS Motor‐CAD software. Thermal analysis revealed that, under S2‐60‐min duty cycle, the stator winding temperature reached approximately 155°C, and under prolonged operation, the temperature approached insulation limits. In simulations where 10 consecutive WLTP Class 1 cycles have been applied, temperature rise trends and energy consumption data have been evaluated over a total operating period of 2.84 h. To examine the effect of gear ratio on performance, various ratios between 5 and 15 have been tested, and the motor's torque, speed, efficiency, and regenerative energy recovery characteristics have been compared. The results showed that selecting a gear ratio of 7 provided the most favorable operating conditions, with an average efficiency of 88.88%, cycle‐averaged instantaneous efficiency of 68.44%, and 60.17 Wh of regenerative energy recovery. Furthermore, it has been determined that high‐ratio operating scenarios led to a rapid increase in thermal load, necessitating additional cooling measures.