Design Method of Hybrid Magnet Arrangement in Variable Flux Memory Machines Based on Elementary-Unit-Combined Concept

Benefiting from the distinct capability enabling flexible flux regulation, variable flux memory machines (VFMMs) are considered as an excellent candidate for electric vehicles to achieve overall high efficiency. However, the structural connections and evolutionary laws between different VFMMs remain unrevealed, resulting in the lack of a comprehensive design method for VFMMs. This article investigates the VFMMs with various permanent magnet (PM) arrangements from the perspective of the elementary-unit-combined concept. Besides, a topology construction method and several novel topologies for VFMM are further proposed. First, the evolution of different magnetic circuits and their inherent characteristics are introduced to form a series of emerging single- and dual-layer PM configurations. Meanwhile, a topology construction method based on the elementary-unit-combined concept is proposed, as well as three novel hybrid magnetic circuit (HMC) topologies are deduced based on three elementary units. Then, the electromagnetic characteristics in the existing and newly proposed HMC-VFMMs are comprehensively investigated utilizing the simplified magnetic circuit model and the finite element (FE) method. Finally, an HMC-VFMM prototype is manufactured and tested to confirm the validity of the previous analyses.