Electromagnetic‐Thermal Bi‐directional Coupling Analysis of IEF‐DDPMM Under Different Operation Conditions and Cooling System Optimization Design

Abstract

Compared with the traditional single stator permanent magnet (PM) direct‐drive motor, the direct‐drive PM motor with inner enhance force (IEF‐DDPMM) has the advantages of high‐torque density, strong heavy‐load starting ability and flexible operation mode, so it is especially suitable for the occasions such as mine winches with a wide load range, frequent heavy‐load starting, light‐load operation, and limited use environment space. It is very important to check the temperature rise of IEF‐DDPMM according to its different operating conditions, including transient temperature rise during heavy‐load starting and steady‐state temperature rise during rated operation, so as to optimize the electromagnetic and thermal performance at the same time. Based on the bi‐directional coupling method (BDCM) of the electromagnetic field and temperature field, the thermal analysis of IEF‐DDPMM and the transient temperature field analysis of the inner motor as a torque motor for short‐term operation are carried out, and then the rated power of inner motor in S1 working system and the maximum operation time of output peak power are determined. The fluid–solid coupling analysis method is used to optimize the design of the cooling system, and the influence of the number of water channels and inlet water velocity on the heat dissipation effect of the motor is analyzed. A cooling system with strong heat dissipation ability is obtained, which can achieve higher power or torque output within the temperature range of winding insulation or demagnetization limitation of PM. Finally, a prototype is developed and equipped with a temperature rise experimental platform, and the experimental results provided a good verification of the simulation results. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.