Thermal–Electromagnetic Analysis for Driving Cycles of Embedded Flux-Switching Permanent-Magnet Motors

Abstract

This paper presents a fast and precise electromagnetic-thermal model of a redundant dual-star flux-switching permanent-magnet (FSPM) motor for embedded applications with driving cycles, e.g., hybrid electrical vehicle (HEV) and aerospace. This model is based on a prior steady characterization by finite-element method (FEM) 2-D of the FSPM motor via calculating the instantaneous torque and the normal and tangential components of the magnetic flux density ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</sub> ) of each element of the stator and the rotor for different root-mean-square (RMS) current densities and different rotor positions. These results are then used in the analytical copper and iron loss models for calculating the instantaneous copper and rotor and stator iron losses during one driving cycle. The lumped-parameter (LP) and finite-element 2-D transient thermal models are then carried out, in which the previously obtained instantaneous power losses are used as heat sources for calculating the temperatures of different motor parts during driving cycles. In the thermal studies, a transformation of an irregular slot structure into a regular (rectangular) one is applied to simplify the calculation of the winding thermal resistance. The thermal-electromagnetic analysis method in this paper can also be extended for all the other applications with driving cycles. The experimental tests are carried out to validate the analytical and numerical results.