Analytical Subdomain Model for Double-Stator Permanent Magnet Synchronous Machine with Surface-Mounted Radial Magnetization

Abstract

This paper proposes an analytical subdomain model for predicting magnetic field distributions in a three-phase double-stator permanent magnet synchronous machine (DS-PMSM) during open-circuit and on-load conditions. The geometric structure of DS-PMSM is quite challenging since the stator cores are located in the outer and inner parts of the motor, while the rotor magnets are placed between these two stators. Parameters that influence the motor performance in DS-PMSM include stator outer radius, stator inner radius, magnet thickness, magnet arc, slot opening, outer and inner airgap thickness and the number of winding turns. The analytical subdomain model proposed in this paper, which can accurately predict the performances of DS-PMSM with less computational time, has an excellent advantage as a rapid design tool. The model is initially generated using the separation of variables technique in four subdomains, namely, outer airgap, outer magnet, inner magnet, and inner airgap, based on Laplace’s and Poisson’s equations in polar coordinates. The field solutions in each subdomain are derived by applying the appropriate boundary and interface conditions. Furthermore, finite element analysis (FEA) is used to validate the analytical results in fractional DS-PMSM with a different number of slots between outer and inner stators and a non-overlapping winding configuration. The electromagnetic performances that have been evaluated are the slotted airgap flux density, back-emf and output torque. The results demonstrate that the proposed analytical model is able to predict the magnetic field distributions accurately in DS-PMSM.

Electromagnetic Characteristics of Dual-Air-Gap Surface Permanent Magnet Synchronous Motor

“…This results in the two parts of the stator and rotor not interacting or being electromagnetically connected, thus creating an arrangement similar to having two motors. This unique feature distinguishes the proposed motor from those in [28,29], where the opposite magnets have the same polarity and the adjacent magnets have different polarities. In addition, the proposed magnet arrangement has the advantage of creating a short flux path, which results in the formation of a local loop between the inner magnets and the inner stator, and vice versa.…”

Study on Electromagnetic Performance of Permanent Magnet Rotor and Dual Stator Starter Generator for Electric Vehicle Range Extender

“…The motor increases the reluctance of the magnetic circuit compared with a single-stator flux-switched motor, solving the problem of oversaturation of the motor's magnetic chain, and the output torque is stable and smooth. Ahmad et al proposed a surface-inserted double-stator permanent magnet synchronous motor [18]. The permanent magnets of this machine are surface-inserted structure, which can make full use of the reluctance torque generated by the asymmetry of the rotor magnetic circuit, and the internal and external double-surface-posted structure of the magnetic line of force mainly passes through the rotor core in the radial direction, which may not take into account the degree of saturation of the rotor core, and thus the rotor core can be designed thin enough to make full use of the internal space of the motor, as far as the strength of the mechanical structure permits.…”