Modeling and Experimental Characterization of Core Loss of A Switched Reluctance Machine

Abstract

Core loss significantly impacts the efficiency and thermal performance of Switched Reluctance Machines (SRMs), especially under high speeds. Conventional measurement methods are often inadequate for capturing losses in assembled stator cores, where flux paths are complex, and excitation waveforms are non-sinusoidal. This thesis addresses these limitations by developing and experimentally validating a practical core loss characterization method tailored for SRM stators. The study begins with a comprehensive review of core loss mechanisms and measurement challenges, highlighting the effects of manufacturing processes such as punching and welding on material properties. A core loss measurement method is introduced based on transformer induction theory, enabling time-domain reconstruction of magnetic field quantities from voltage and current waveforms. The method is validated using a ring core and SRM stator geometry with finite element analysis (FEA), replicating practical excitation conditions. An experimental setup is built with a fractional SRM stator core and custom magnetizing yokes. The experimental setup captures induced voltage and current waveforms from the stator. The proposed method is experimentally validated over a wide frequency range from 100 Hz to 10,000 Hz and under varying flux density levels, confirming the applicability for practical core loss characterization of SRM stators.