Design And Research On Axial Flux Motor Based On SMC Material

Axial flux motor has the advantages of high torque density,high efficiency,and compactness,which are very suitable for electric vehicles,aircraft,wind power generation,and other fields.The stator iron of the axial flux motor has a main magnetic flux along the axial direction,which generates a three-dimensional magnetic circuit.The difficulty in manufacturing the stator iron with silicon steel laminations is a key issue that limits the widespread production and application of axial flux motors.Soft magnetic composite(SMC)is a new type of composite material made by mixing ferromagnetic powder with organic materials,which can be rapidly and conveniently shaped by compression molding.Therefore,the use of SMC materials is one of the important directions for the future development of axial flux motors.Based on the characteristics of SMC materials,the key issues of torque output and efficiency of SMC material yokeless segmented armature(YASA)axial flux motor are analyzed in this paper.An optimized stator structure is proposed in this thesis,which improves the torque and efficiency of YASA motors made of SMC materials.Firstly,are introduced the basic principle of YASA motor by combining the structural characteristics and magnetic circuit characteristics of axial flux motors.By studying the design factors such as the overall dimensions of the motor,the matching of the pole slots,the stator structure,and rotor structure,is determined the YASA motor preliminary design scheme.The no-load and on-load characteristics of YASA motor are analyzed by finite element method to ensure the rationality of motor design,which laid a foundation for the comparative study of YASA motors with different stator materials.The permeability of SMC material is slightly lower than that of silicon steel material,which affects the torque output of the motor.Therefore,optimizing the motor structure and improving the torque coefficient are the key issues in the research of SMC material YASA motors.Based on the comparative analysis of SMC and silicon steel materials,the electromagnetic characteristic changes of the YASA motor after replacing silicon steel with SMC material are studied.Based on the three-dimensional magnetic circuit of the YASA motor,an optimization structure based on the expansion of the stator teeth is proposed,which improves the output torque of the SMC material YASA motor.At the same time,based on the two-rotor displacement method,the torque ripple is weakened,and the torque performance of the motor is improved.In addition,the iron loss coefficient of SMC material is higher than that of silicon steel at low frequencies,and the trend is opposite at high frequencies.As axial flux motors are generally not used in high-speed conditions due to their structural characteristics,reducing losses is another key issue for SMC material YASA motors.The reasons for the various losses of YASA motors are analyzed,and the variation law of the eddy current loss of the permanent magnet under different segmenting methods and segmenting numbers is summarized.Considering the advantages of SMC materials and silicon steel laminations,a combined iron core based on SMC material and silicon steel is proposed,which effectively reduces the iron loss of the YASA motor.By combining the above methods,the efficiency of the SMC material YASA motor is improved.