High-Torque Electric Motors with Coil Cooling via Thermal Model and Peltier Element

This paper proposes a motor coil cooling method to realize high-torque motors with a Peltier element. The conventional method for increasing the maximum torque of motors entails applying an overcurrent under the temperature limits of the coil. However, when this overcurrent is applied, the Joule heat generated by the coil must be actively dissipated. Further, when the overcurrent is passed again, a severe thermal constraint is imposed on the motors. High cooling performance is essential for motors with overcurrents. Therefore, to improve the maximum motor torque, a Peltier element, which is a cooling device, was employed in this study. In addition, the motors were covered with motor housings. This, however, made it difficult to measure the temperature of the coils. Thus, to estimate the coil temperatures without using temperature sensors, a thermal model of the Peltier element and the motor was designed. Using this thermal model, a suitable current was selected to maximize the cooling performance. Moreover, the thermal models of the coil and heat-absorbing surface of the Pelche element were compared with the measured values for verification.