Research On Design And Control Technology Of Salient Pole Electromagnetic And Combined Permanent Magnet Composite Excitation Hub Motor For Electric Vehicle

Salient pole electromagnetic and combined permanent magnet hybrid excitation hub motor for electric vehicle have the advantages of both permanent magnet motor and electric excitation motor.It has high power density and good magnetic regulation performance.It eliminates the complex transmission structure of traditional drive motor for electric vehicle and reduces the energy loss in the process of power transmission.It has become an important type of drive system for electric vehicle.Based on the analysis of the performance requirements of driving system under different operating conditions of electric vehicle,the parameters of composite excitation hub motor are matched with the basic parameters of a small low-speed pure electric vehicle,and a composite excitation hub motor combining salient electromagnetism and combined permanent magnetism is designed.The parameters of stator and rotor of hub motor are designed,the pole slot matching form of 3-phase 18-pole 54-slot double-layer integer slot winding is determined,and the parameters of armature winding are calculated to complete the overall design of salient pole electromagnetic and combined permanent magnet drive motor.The equivalent magnetic circuit model of the hybrid excitation drive motor is established,and the calculation methods of the main magnetic conductivity,leakage magnetic conductivity,effective magnetic flux and leakage magnetic flux in the magnetic circuit are derived by solving the magnetic circuit model.The static,transient,half-load and full-load simulation analysis of the motor is carried out by using finite element analysis software.The magnetic field intensity distribution,magnetic line direction,three-phase back-EMF waveform,excitation coil increasing and weakening ability,half-load and full-load speed curves and torque curves of the driving motor considering starting process under no-load and load conditions are analyzed to verify the design of the motor.Rationality of calculation.The main components of hub motor are analyzed,such as iron loss,copper loss and eddy current loss.The whole structure of the motor is analyzed by coupling magnetic field with transient thermal field.The temperature distribution of the motor under half-load,rated load and overload conditions for 100 minutes is studied.The results show that the temperature of the key components of the motor is within a reasonable range.The flux linkage equation,voltage equation and torque equation of compound excitation hub motor are established.The motor control methods under four typical operating conditions,namely,low speed standard area,low speed magnetization and torsion enhancement area,high speed standard area and high speed weak magnetic expansion area,are analyzed.The simulation model of compound excitation motor is built by using MATLAB/Simulink software.The rationality of the control method is verified by the output characteristics of the motor..