Research Of A Multistage Axial Flux Permanent Magnet Machine

With the announcement of PM2.5, people pay more and more attention to the environmental pollution, and electric vehicles(EVs) is becoming an important way of transportation in the future. With EVs drive systems developing tends to high torque density, high efficiency, and wide speed range, axial flux permanent magnet machine(AFPM) with a compact disc, high torque density and efficiency characteristics, is particularly suitable for electric drive system. However, the researches on AFPM are still not advanced in our country, it still needs further research and development. Therefore, this paper carries out a series of studies on the AFPM and proposes a new multistage AFPM with three rotors and two yokeless stators.Firstly, the paper discusses the existing topology of AFPM, and analyses the characteristics and performance of the existing topology, a comprehensive narrative about the main components of AFPM such as material, structure, is developed in this paper. Moreover, a new multistage AFPM with three rotor and two yokeless stator is proposed, and the details and analysis are presented in this paper.Secondly, according to the analysis of the requirements of the drive system, the main dimensions of the machine are determined with the theories and experiences. By using the finite element analysis(FEA) software Ansoft Maxwell, a 3D Electromagnetic field calculation is found. The paper discusses a number of key parameters such as slot opening pole, arc ratio on the performance of machine, and optimize the key parameters to verification the requirements.In addition, the paper studies the mechanism of inhibition of cogging torque. According to topology of the machine proposed in the paper, the performance on the machine with slots-arc combination is discussed. Based on the topology of the machine, the asymmetrical bidirectional magnet skewing technique and stator displacement technique are proposed to minimize the cogging torque, the relevant simulation analysis is presented in the paper, and it is proved to be effective.Finally, the details and process of manufacturing the prototype are presented. It will provide some experiences for the manufacture of AFPM in the future. And a well agreed result between the ones measured by experiments and those predicated by FEA is exhibited. Through experiments carried on the prototype, the analysis in the paper is validated.