The aim of this research was to investigate the torque performance of the motor in an electric vehicle depending on the rotor shape and air gap. The research focused on numerical comparison of torque performance of new rotors based on the average torque and torque ripple rate, which appeared according to the number and placement of permanent magnets. This research was numerically analyzed by MAXWELL V21.1. Average torque values in cases 1, 2, and 3 were increased, but vibration and noise in cases 1 and 3 were increased as the torque ripple rate increased. Considering the average torque and torque ripple rate, the torque performance of case 2 was the most optimal. Compared with Model N, the average torque of case 2 was increased by 9.1% and the torque ripple rate was reduced by 1.5%. The torque performance according to the size of air gap was compared with the basic model of case 2, which showed the best performance. An air gap of 0.7 mm applied to Model N showed the best torque performance. An additional magnet on case 2 and air gap of 0.7 mm provided the best torque performance and improved the driving motor performance for motor durability.

This research is to investigate the cooling performance of the motor in the electric vehicle depending on the cooling channel fin. The research focused on numerical study of the temperature of coil and cooling channel and the heat transfer coefficients to find a optimum design shape with high cooling performance at three different cases. To compare the convective cooling performance of the three cooling channels, local position (R) are displayed on the surface of the coils with a large temperature deviation. This research was performed on forced convection and was numerically analyzed by FLUENT V20.2. Owing to forced convection by the same mass flow, the average cooling channel velocity in Case 3 was 17.4% faster than Case 1 and 8.6% faster than Case 2. Out of the three cases, the highest heat transfer coefficient was found in the cooling channel and coil of Case 3, which had two cooling fins. The coil maximum temperature of Case 3 with 2 cooling fins was 4.7% lower than Case 1 without cooling fins and 1.7% lower than Case 2 with 1 cooling fin. Ultimately, Case 3 with two cooling fins provided the best cooling performance and improved driving motor performance for motor durability.

This research investigated the cooling performance of the motor in electric vehicle depending on the shape of the cooling channel. The research, conducted numerically by FLUENT V20.1, focused on the numerical study of heat transfer coefficients to find an optimum design shape with high cooling performance. To compare the cooling performance, the temperatures in the coil and cooling channel were analyzed. As a result of forced convection, the average cooling channel velocity of Case 2 was 38% faster than Model N and 34% faster than Case 1. The maximum temperature of the cooling channel of Case 2 was 8.7% lower than Model N and 5.6% lower than Case 1. The minimum temperature of the coil of Case 2 was 2.7% lower than Model N and 4.3% lower than Case 1. The maximum temperature of the coil of Case 2 was 4.6% lower than Model N and 2.9% lower than Case 1. Ultimately, cooling channel of Case 2 showed the best cooling performance and improved driving performance for motor durability.