Comparative Analysis of Two Different Types of Blended Permanent Magnet Assisted Synchronous Reluctance Machine

Abstract

The design and optimization procedure of two different types of PM-assisted synchronous reluctance machine (PMASynRM) made of different types of PMs: Ferrite and NdFeB will be proposed in the paper. The two different types of PMASynRM are designed for the traction application and will be compared to a two-layer V-type IPM with NdFeB magnets only, which is used as the baseline design. The proposed two different types of designs have the same stator geometry and winding configuration as the baseline design. The main purpose in the paper is to reduce NdFeB PM content by investigating and comparing two different types of blended design PMASynRM, namely, a parallel hybrid design and a series hybrid design. The key challenges when reducing the rare-earth content are: (1) Maintaining the same rated torque as the baseline (2) Reducing even eliminating the risk of demagnetization due to the lower coercivity of ferrites at both low and high temperature. In the paper, we will focus on the comparative analysis of two different types of PMASynRM by means of the presented optimization process with emphasis on assessing the level of permanent demagnetization risk. In order to assess the structural integrity of the rotor, a mechanical analysis was conducted in parallel design. The proposed parrel design can generate competitive torque as the baseline design with around 25% reduction of rare-earth material while eliminating the demagnetization risk at the extreme low operating temperature of -20°C and high temperature of 150°C. The paper includes details of the optimization process and corresponding sample results, evaluation of demagnetization risk of both types of PMASynRM designs, and analysis and optimization results of both types of designs.