Study On Electromagnetic Performance Of Permanent Magnet Brushless DC Motor With CAM Rotor

Compared with the traditional "three-stage" hydraulic power unit,the motor pump has the advantages of small volume,compact structure,low noise,no leakage and high efficiency,which makes it of great significance in research and broad application prospect.Existing motor pump products or research prototype are focused on the integration of motor and hydraulic pump "package",that is,the hydraulic pump in the axial direction or radial direction and motor integration,sharing a shell;For the axial integration,the axial size is still large and the integration is not high.For radial integration,hollowing out the rotor of the motor to install the hydraulic pump will affect the magnetic circuit of the motor rotor,and then affect the performance of the motor.The rotor of the CAM rotor vane pump is designed as the rotor of the motor,and the stator is combined with the stator of the motor.When the motor output torque at the same time,the function of the vane pump will be realized,this structure of the motor pump on the basis of not significantly affecting and changing the magnetic circuit layout of the motor rotor,can achieve a high degree of axial and radial integration of the pump and motor.In this paper,the motor of the two-section CAM rotor structure as the research object,the existing permanent magnet brushless dc motor rotor processing into two sections of CAM,phase difference of the two sections of 90 degrees,because the rotor rotation,the constant air gap between the rotor size changes will have an impact on the motor performance,so the research on the performance of the difference between the CAM rotor motor and the uniform air gap motor,so as to lay a foundation for the research of the CAM rotor hydraulic motor pump.The main work of the paper includes:(1)The structure origin and application background of CAM rotor motor are introduced.The structure of CAM rotor and its transition curve equation are introduced.The components of CAM rotor motor and the rotation principle of CAM rotor motor are introduced in detail.(2)The basic theory of electromagnetic field and Jmag finite element electromagnetic simulation software are introduced.Three-dimensional modeling was carried out for the prototype of CAM rotor motor,and the simulation process of CAM rotor motor was introduced from modeling,condition setting,mesh dividing and drivecircuit setting by using the electromagnetic simulation module of Jmag software.(3)The electromagnetic field simulation was carried out for the uniform air-gap motor formed by the CAM rotor motor and the two limit arcs of the CAM rotor geometric curve(Rmax=12.9 and Rmin=12.2)under no-load and rated load conditions.From the simulation results,several parameters such as speed curve,current curve,output torque curve and air gap magnetic density curve of three kinds of motors are obtained,and the performance characteristics of CAM rotor motor are obtained by comparing these performance parameters.The torque ripple and efficiency of the three motors under two working conditions of constant speed of1800 rpm and 1500 rpm were compared.The electromagnetic field distribution of three kinds of motors under different working conditions is discussed in the form of cloud image.(4)The speed,current and other related parameters of CAM rotor motor and R=12.9 and R=12.2 uniform air-gap motors under 6 constant load conditions from0 Nm to 1.25 nm were extracted,and the mechanical characteristic curve,output power curve and efficiency curve of the three motors were drawn to analyze the performance under different constant load conditions of CAM rotor motor.(5)The experimental device of CAM rotor motor and its working principle are introduced.Put the CAM rotor motor into the experimental device to load different constant loads,and then read the experimental data of motor performance parameters under different constant loads,draw the curve of the experimental data and compare it with the curve of the simulation parameters,get the error between the two,and verify the reliability of the simulation.(6)The losses of CAM rotor motor and two kinds of uniform air gap motor are calculated,and the loss characteristics of CAM rotor motor are analyzed.The temperature field analysis module of Jmag software was used to model and simulate the temperature rise of CAM rotor motor.