Cooling Channel Design and Temperature Field Analysis of a Lightweight High-Efficiency Drive Motor

ABSTRACT: The temperature rise in lightweight, high-efficiency traction motors for new energy vehicles (NEVs) directly affects their operating efficiency, reliability, and service life. In this study, a permanent magnet synchronous motor (PMSM) for NEVs was selected as the research object, and three distributed cooling channel configurations, namely spiral, tree-shaped, and circumferential channels, were comparatively investigated using conjugate fluid–thermal simulations. The effects of cooling-channel configuration and coolant flow rate on the motor temperature and flow characteristics were analyzed. Under the rated operating condition with a total coolant flow rate of 10 L/min, the maximum motor temperatures of the spiral, tree-shaped, and circumferential configurations were 98.2 °C, 97.2 °C, and 99.6 °C, respectively. The tree-shaped cooling channel, therefore, exhibited the best thermal performance and the smallest maximum inlet-to-outlet static gauge-pressure difference among the three configurations. Based on the thermal constraints and the variation in this defined pressure metric, recommended coolant flow rates of 12 L/min and 22 L/min were selected for the peak-speed and peak-torque operating conditions, respectively.