Robustness of Dynamic FEA-based Demagnetization Calculation in the Multi-Objective Optimization of PM-assisted Synchronous Reluctance Motor with Blended Magnets

Abstract

This paper analyzes the impact of FEA-based demagnetization assessment methods on the multi-objective optimization analysis of 2-layer PM-assisted Synchronous reluctance motor having two magnet combinations of rare earth permanent magnets (NdFeB) with Iron Nitride (FeN) magnets and Dysprosium free NdFeB (Dy-free NdFeB) with FeN magnets. The 2-layer Chevy-Bolt traction motor with NdFeB magnets is considered as the baseline design. The metaheuristic optimization based on Differential Evolution (DE) algorithm is used for the multi-objective optimization analysis of the machine. Detailed comparison and analysis of four methods of demagnetization computation namely, knee point method, percentage demagnetization method, peak current based back-emf (B-EMF) reduction method and conventional B-EMF reduction methods are discussed in this paper. The demagnetization study is evaluated for the best designs obtained from the optimization analysis at extreme temperatures of -20°C and 150°C. The impact of these methods on the pareto front obtained from the optimization procedure is also analyzed.