| Large-scale open-pit mines generally use large mining engineering vehicles to transport materials,and the electric drive system can effectively solve the problems of low efficiency,high pollution and low reliability of diesel engines and mechanical transmission.However,its traction motors mostly use DC motors at this stage,which have the shortcomings of simple structure,low efficiency and poor reliability.Compared with permanent magnet motors,axial flux permanent magnet motors have greater torque density,higher efficiency,and The smaller volume is more suitable for installation on mining engineering vehicles with limited space.This article takes a mining engineering vehicle as an example to study the axial flux traction motor.First of all,when the mining engineering vehicle is in a climbing,accelerating and constant speed state,the motor working conditions are different,and it is necessary to comprehensively calculate the motor power and torque according to the output characteristics of the motor in different operating states.Design analysis of conventional permanent magnet motor calculations shows that the axial length of the motor is difficult to meet the installation volume.However,the output torque of the axial flux permanent magnet motor is positively related to the radial size and has nothing to do with the axial length.Therefore,this paper selects the axial flux permanent magnet motor for research and analysis.Secondly,the different topological structures of the axial flux permanent magnet motor are analyzed,and the advantages and disadvantages of the bilateral structure are compared.In view of the uneven road surface of mining engineering vehicles and the poor heat dissipation capacity of the motor,the structure of double stator and single rotor with built-in permanent magnets is selected.Compare the cogging torque under different pole slot numbers,pole arc coefficients,and torque ripple under different oblique pole angles,determine the number of poles,slot numbers,and pole arc coefficients of permanent magnets to obtain the electromagnetic scheme of the motor.The winding function method is used to analyze the stator magnetomotive force under different pole-slot matching and the freezing permeability method is used to calculate the quadrature-direction axis inductance.The calculation efficiency MAP diagram and the drawing of the mechanical characteristic curve are used to analyze the no-load,load and overload conditions of the motor.Finally,in order to prevent the temperature rise of the motor from being too high,calculate the loss of each part of the motor as a heat source to verify that the temperature rise of the winding and the permanent magnet is within a reasonable range.Due to the large speed range of the traction motor of mining engineering vehicles,it is necessary to perform modal analysis on the rotor to verify that the motor rotor does not resonate.In order to ensure the strength of the rotor,it is analyzed that the deformation of the rotor at different temperatures and maximum speeds will not affect the reliability of the motor. |
