A 3D Thermal Model of SynRM with Segmented Rotor Considering Anisotropic Conductivity

This paper presents a lumped-parameter thermal network (LPTN) model construction of a synchronous reluctance machine (SynRM) with segmented rotor and its validation. The 180W machine is intended to actuate an automotive clutch thus, installed in an ambient temperature up to 140◦C. In such machine, to make sure that a precise prediction of the temperature inside the machine can be achieved, deduction of thermal resistance of anisotropic component, surface contact, and external casing convection need particular attention. The external casing convection has been experimentally identified. The contact resistance between components were computed using effective airgap. The method used to compute thermal resistances of anisotropic component and surface contact are explained. The identification method used to deduce the thermal resistance of external surface is also presented. Finally, a validation experiments at different operating points of copper losses have shown that the 3D LPTN model is precise and robust with a maximum error of less than 3% at both transient and steady state.