Lumped-Parameter Thermal Model for a Double-Rotor Flux-Switching Permanent-Magnet Machine

A lumped-parameter (LP) thermal model is presented for a flux-switching permanent-magnet double-rotor machine (FSPM-DRM) used for hybrid electric vehicles (HEVs), which has attracted attention due to the compact structure. The model provides the steady-state thermal solution to derive the temperatures at different parts of the machine, including the temperatures in the stator windings and the temperatures of the magnets. Temperature-dependent thermal properties of the materials used in the machine construction as well as the stator resistance and consequently copper losses require temperature update in accurate design of the machine. Therefore, an iterative coupled electromagnetic and thermal design program is proposed in this paper. A l-kW/l-kW FSPM-DRM prototype machine is designed and manufactured. Tests performed on the designed machine verify that the defined thermal resistance network has a high ability to predict the nodal temperatures accurately.