Analysis and Modeling of Permanent Magnet Variable Flux Memory Motors Using Magnetic Equivalent Circuit Method

This paper presents an analytical method based on the magnetic equivalent circuit to derive permanent magnet (PM) load-lines of two general types of a variable flux memory motor (VFMM), which are circumferentially embedded (CE)-type and radially embedded (RE)-type PM motors. The proposed PM load-line models are valid and suitable for investigating the PM magnetization characteristics of VFMMs. It is validated via visible comparison with the PM load-lines derived by the finite-element method. Furthermore, by making use of the proposed method, the magnetization characteristics of several CE and RE VFMMs, which have different geometry parameters, have been examined and compared. According to the analysis results, RE-type VFMMs require approximately ten times larger remagnetizing field than CE-type VFMMs, although RE VFMMs are further influenced by demagnetizing field than CE VFMMs.