The Research Of Coaxial Permanent Magnet Gear Composite Motor Based On Rare Earth

Coaxial Permanent Magnetic Gear belongs to high torque density(for existing permanent magnet motor torque density more than 2 times),efficient operation and contactless power transfer magnetic transmission mechanism.A permanent magnet compound motor with the same torque density as CPMG can be obtained by combining CPMG with permanent magnet motor.In this paper,the development of permanent magnet motor,permanent magnet gear and permanent magnet motor are introduced in detail Based on the advantages and disadvantages of the above devices,a new permanent magnet compound motor based on the concentric permanent magnet gear is proposed.The mechanical structure and operation mechanism of CPCM core components,CPMG,were analyzed,and the mathematical model of the air gap magnetic field of CPMG was established,and the modulation function needed for the CPMG magnetic ring was derived.The mechanical structure parameters of CPMG are preliminarily determined,including the transmission ratio,the shape volume and the magnetic poles of the inner and outer rotor,etc.,and the required CPMG simulation model is established in the ANSYS simulation environment.The finite element simulation and Fourier transform of the inner and outer rotor air gap magnetic field of CPMG in two states with and without the magnetic ring are verified,and the correctness of the theoretical analysis and calculation results is verified.Based on the static and dynamic characteristic curves of CPMG torque,the permanent magnet shape and magnetic ring structure of CPMG are optimized.The relationship between the thickness of the magnetic ring,the thickness of the permanent magnet,the length of the outer air gap and the output torque density is obtained by using the control variable method.The optimal values of the above parameters are selected,and the CPMG model with high torque density and high stability is obtained.The optimized CPMG and permanent magnet motor were combined to obtain the required CPCM model.The main structural parameters and the equivalent magnetic circuit of CPCM are analyzed,and the dynamic torque and speed characteristic curves of CPCM are obtained by simulation.Through the study of its dynamic characteristics,it is proved that CPCM has the operation characteristics of permanent magnet motor and the operation characteristic of the same type permanent magnet gear,that is,its output characteristic has the function of transmission ratio.The CPCM common three kinds of startup methods and corresponding research in the form of three kinds of load to obtain the corresponding rotational speed and torque characteristic curve,select the minimum amplitude,the stability of the highest starting way.The loss of CPCM is simulated and analyzed,and the main loss(i.e.core loss)curve is obtained.According to the influence rule of CPCM stator tooth,yoke magnetic density and iron core loss,CPCM was optimized to reduce the loss of CPCM,and the CPCM model with higher working efficiency and better stability was obtained.