Magnetic and Thermal Modeling of Hollow Conductors for Improved Cooling and Force Density of Coreless Linear Motors

The feasibility of using direct liquid cooled hollow conductors (HCs) in coreless linear motors is evaluated in this article. HCs with direct water cooling can significantly improve the heat dissipation inside electrical machines. Two different concepts for winding coils from HCs are considered. A moving coil and moving magnet topology (MMT) are analyzed. The magnetic models, based on harmonic and surface charge models, and a 3-D thermal equivalent circuit (TEC) model are used to model the coils. The models are validated via an FEM analysis. A coupled electromagnetic–thermal analysis is implemented. Furthermore, the proposed motor with HCs is compared with a state-of-the-art (SotA) direct liquid cooled linear motor. The proposed topology with HCs shows an improvement of the cooling performance, compared with the SotA motor. However, a much higher current is required to achieve a similar force profile, which makes the moving magnets topology more attractive, considering the mass of the cables necessary.