Advanced Theory of Fractional-Slot Concentrated-Wound Permanent Magnet Synchronous Machines pp 95-126 | Cite as

# Analytical Modelling of Rotor Magnetic Characteristics in an Interior Permanent Magnet Rotor

## Abstract

This chapter proposes a technique for analytical modelling of the non-homogenous magnetic saturation in the IPM rotor iron, based on which an analytical model for calculation of the PM flux density is proposed. The principles of the magnetic equivalent circuit in electric machines are first explained. The flux paths in a V-shaped IPM rotor due to the magnet residual flux are then classified into five groups. Accordingly, geometrical relationships in the IPM rotor are derived and used in analytical modelling of the non-homogenous magnetic saturation in the rotor iron. The *B*-*H* curve of the rotor core material is taken into account in the proposed approach. The proposed model provides information regarding the flux density and relative permeability of the iron in different regions of the rotor. In the next step, the state of the art analytical model for the PM flux density in the airgap is briefed, for which, a novel model is then proposed that is based on the novel magnetic saturation map that was derived earlier in this chapter. A case-study was then investigated to evaluate the proposed techniques using FEA and experimental results from the prototype machine.

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