Search

Purpose – The purpose of this paper is to investigate the influence of end-effect and cross-coupling on the torque-speed characteristics of switched flux permanent magnet (SFPM) machines. Design/methodology/approach – The torque-speed characteristics are predicted using two different methods. These are direct and indirect finite element methods, at different cross-coupling levels, namely, full cross-coupling on both PM flux linkage and dq-axis inductances, partial cross-coupling on the PM flux linkage only and without cross-coupling. Findings – The influence of the cross-coupling on dq-axis inductances of the studied machine is relatively small. However, it is more significant on the PM flux linkage. Therefore, the partial cross-coupling model, which is much easier and faster, exhibits almost the same accuracy as the full cross-coupling model. Furthermore, the end-effect causes a large reduction in torque-speed characteristics. However, such a reduction is more significant in the flux weakening operation region. Originality/value – This is the first time that the influence of end-effect of SFPM machines on the torque-speed characteristics, especially in flux weakening region, and on the dq-axis inductances has been investigated. [ABSTRACT FROM AUTHOR]

Purpose – Transient torque calculations of the parallel flux switching machines, both cogging and electromagnetic, require a long simulation time for transient analyses. This paper seeks to present an optimization method for the accurate but time consuming transient models. Design/methodology/approach – A superposition principle is used to optimize the simulation time of the machine model. Finite element method (FEM) is chosen as the example machine model, since it is widely used among researchers for its accuracy. The machine geometry is simplified by reducing the number of rotor teeth, because these parts are re-meshed with each transient step. Torque results are compared to the full machine model to find the best representation. Findings – Among compared simplified machine geometries, the two teeth model gives the most accurate results. Research limitations/implications – The superposition method requires a modelling method such as FEM. The method offers a geometrical simplification of the machine, not a complete model. Practical implications – Parallel flux switching machines should be considered as promising candidates for hybrid and electrical truck applications due to their high power density. For these kind of applications, a fast torque estimation tool helps greatly in investigating noise related mechanical problems, which have a direct effect in passenger comfort. Originality/value – Whereas researchers in this area mainly focus on accurate but time-consuming modeling of this nonlinear machine, this research shows an optimization of these methods to speed-up them. The proposed optimization method can be integrated with any analytical or numerical machine model. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to compare the performance of conventional, novel E- and C-core switched-flux permanent magnet (SFPM) machines having different combinations of stator and rotor pole numbers, with particular reference to the conductor and magnet eddy current loss and iron loss. Design/methodology/approach – The electromagnetic performance of the analysed machines is compared using the finite element (FE) analysis. Findings – Both iron and conductor eddy current losses increase with the rotor pole number, while the 11- and 13-rotor pole machine always exhibit lower magnet eddy current loss than those of the 10- and 14-rotor pole machines, respectively. The E- and C-core machines use half the number and volume of magnets and also exhibit higher efficiency than those of the conventional SFPM machine. Originality/value – Investigation of the influence of stator and rotor pole combinations on the performances of conventional, novel E- and C-core SFPM machines, include losses and efficiency. [ABSTRACT FROM AUTHOR]