A NEW DESIGN METHOD FOR LOW-SPEED TORUS TYPE AFPM MACHINE FOR HEV APPLICATIONS

Abstract

Axial flux permanent magnet (AFPM) machine type has some advantages such as compressed packaging, easy handling, and safety operation. In this paper the proper structure selection of AFPM machine for hybrid electric vehicle (HEV) application is one of the aims. To reduce the losses and the total volume of machine, the coreless TORUS-NS type machine is selected. Designing of this machine, to obtain a wide speed range with high efficiency, low cogging torque and high torque value, as in-wheel direct-drive AFPM machine for HEV, is investigated. The operation performance in low and medium speed ranges is studied. A new design method based on multi speed design (MSD) strategy is proposed. Using this method with a coreless type of stators, the total AFPM machine efficiency at the HEV operation cycles could be improved. Performance analysis of this in-wheel AFPM machine is done using finite-element method (FEM). FEM analysis of the single-speed design (SSD) method is also done. MSD and SSD designed machines are applied in HEV and simulated using urban and highway cycles. The obtained results show the better performance of HEV, using the MSD based designed machine in all operation cycles. The experimental results obtained from sample practical prototype, confirm the analytical method.