A New Method for Improved Design of Low Speed Axial Flux Permanent Magnet Machines Used in HEV

In this paper, the specific application of axial flux permanent magnet (AFPM) machines as an in-wheel direct drive machine used in hybrid electric vehicles (HEV) is presented. Meanwhile a brief study of the merits and demerits of different structures for this type of machine, the most suitable structure for this application is introduced. The general design procedure and common methods for determining the parameters of the final design is presented. A new method to determine the design parameters, based on HEV velocity profiles, is proposed. Using the conventional and the proposed methods, different structures of AFPM are designed and performance analysis of them is done using finite element method. Characteristics of each AFPM are extracted and used in HEV model. The results show that, the overall efficiency of the hybrid car is improved using the electric car designed by the proposed method. Based on the results of the proposed design method, a sample of the AFPM is built and the obtained experimental results are compared with the analytical results.