| Direct-current permanent magnet brushless torque motor has wide speed range and soft mechanical characteristics.It can work in locked rotor condition for a long time.It has been widely used in the field of military industry and modern industrial production.Under the influence of foreign policies towards China,domestic high-end products of direct-current permanent magnet brushless torque motor are highly dependent on foreign imports,and military products are even prohibited.In this context,it is necessary to design out directcurrent permanent magnet brushless torque motors with high torque and precision control.This thesis focuses on the design process of the direct-current permanent magnet brushless torque motor,in order to master the design process of the brushless torque motor,the main contents are as follows:First,select the structure of each part of the direct-current permanent magnet brushless torque motor.The main dimensions are calculated through the two links of preliminary design and electromagnetic design and decide the type of motor pole-slot matching,winding form,material,etc.are compared.The working principles and the advantages of square wave drive and sine wave drive are compared.Second,the multi-physics simulation of the motor has been processed.Firstly,Introduce the basic theory of electromagnetic field before the deformation of Maxwell equations in the motor magnetic field completed.Then the boundary conditions of the electromagnetic field are analyzed.Secondly,the finite element simulation of electromagnetic field is solved,After performance of the electrical machine carried out,the influence of the parameters of the magnet and output performance of the motor is compared.Thirdly,the basic theory of temperature field is introduced.Three models of heat transfer are given,and the mathematical expressions of heat transfer of three models are deduced.The copper and iron loss in the motor are deduced and set them as heat source for finite element simulation to get the temperature field distribution of the motor.Fourthly,the causes and classification of vibration are listed.The distribution of radial electromagnetic force which leads to electromagnetic vibration is calculated,After analying structural mode of motor,the finite element simulation of motor vibration is carried out and show the vibration displacement cloud diagram and frequency response waveform of motor.Finally,the cogging torque of the motor is analyzed.The commonly used cogging torque analysis methods are introduced: energy method,Maxwell tensor method,finite element method and flux magnetomotive force method.The cogging torque reduction method is analyzed by using the cogging torque expression obtained from energy method.In the end,the effectiveness of the cogging torque reduction method is verified by finite element simulation.This thesis does not pursue the ultimate optimization of single physical field performance,but considers the effective combination of finite resources from the perspective of engineering,and the simulation results have the feasibility of later processing and production.The simulation results show that the output characteristics of the motor match the design requirements.The rated torque of the motor under load is 1.3128 N·m,which is only 0.9%different from the initial design input of 1.3 N·m,which verifies the effectiveness of the design method. |
