Research On Structure And Control Method Of Magnetic-Field-Modulated Dual-Stator In-Wheel Motor

In-wheel driving system,which greatly simplifies the vehicle transmission system and improves the dynamic performance,is the main research direction of the next generation of the wire-controlled Electric Vehicle(EV).At present,the in-wheel motor is limited by the space inside the wheel,has the obvious problems of insufficient power density and narrow speed regulation range,and cannot yet meet the driving requirements of the vehicle.Based on magnetic modulation,this paper proposes a dual-stator in-wheel motor driving technology scheme,which can effectively improve torque and control flexibility.Conducting system design and performance research on its electromagnetic structure and motor control methods,the main contents are as follows:This paper first proposes a dual-stator electric mechanism based on the principle of magnetic modulation and designs its key electromagnetic structure parameters.The power requirements of the vehicle under different working conditions are calculated,and the design goals of the motor are proposed;ANSYS/Maxwell is used to carry out electromagnetic field simulation modeling,and FFT analysis of the air gap flux density of the motor is performed to verify the rationality of the electromagnetic structure and calculate the steady-state torque output,which confirms the effect of the dual-stator structure on the promotion of electromagnetic torque.The influence of the structure parameters of the motor on the performance is analyzed.Taking the span and thickness of the magnetic modulation ring as the key object,the electromagnetic torque is simulated and calculated,and the best span and thickness values are obtained.The performance indicators of the motor are calculated,and a motor design with good performance is obtained.Carried out the design of the motor control system.First,the control mode is designed.The inner stator is used as the control winding and the outer stator as the excitation winding,which not only increases the control flexibility but also simplifies the controller structure;Carrying out motor modeling and deriving its mathematical model.Based on the principle of Field Orientation Control(FOC),a schematic diagram of the software and hardware of the control system is proposed.Based on classic PI control and modern control methods,the motor control current loop and speed loop are designed respectively,and the system analysis and comparison are carried out.The results show that the modern control method based on proportional resonance control and sliding mode control can effectively solve the problem of classical PI control.The physical parameters of the motor are sensitive and the dynamic response is slow.In order to obtain a wide range of motor speed regulation,a voltage feedback leading angle field weakening control algorithm is proposed.This method can maximize the use of inverter modulation depth and expand the speed range.Tuning the control law parameters based on MATLAB/Simulink software and carrying out simulation research on controller performance.First,a MATLAB/Simulink simulation model is built;taking the rise time and overshoot in the step response as indicators,the least square indicator is used in MATLAB to iteratively optimize the controller parameters to achieve parameter tuning.The current regulator adopts a proportional resonance control algorithm,which has good performance in phase current overshoot and waveform chattering;the speed regulator adopts a global fast terminal sliding mode control algorithm,which has a faster response speed and dynamic performance to step and ramp function inputs.Simulation and analysis of field weakening speed regulation performance;simulation of acceleration and variable load conditions has short response time and small overshoot.This paper puts forward a new technical scheme for in-wheel driving,systematically studies its electromagnetic structure and control system design method and lays a solid theoretical and technical foundation for its further development and application.