Modeling and Investigation of Thermal Characteristics of a Water-Cooled Permanent-Magnet Linear Motor

For permanent-magnet linear motors (PMLMs), high-temperature rise can deteriorate their electromagnetic performance and limit their thrust output. A water-cooling system can be employed to reduce the temperature rise and to improve the thrust density. In order to study the thermal performance of a water-cooled, 14-pole, and 12-slot PMLM, a finite-element model and thermal network model are developed. Under continuous duty, the temperature distribution of this PMLM is investigated based on the two developed models, which are validated by experimental results. The effect of the water-cooling system and the impact of its parameters on the temperature rise are investigated. Then, the influence of the temperature rise on the motor thrust force and efficiency is studied. Finally, based on the finite-element model, thermal characteristics of this PMLM under short-time duty and intermittent duty are studied, and the relationship is obtained between the operation duration and the maximum allowed short-time current, as well as the impact of load sustained rate.