Deadbeat-direct Torque And Flux Contorl Of A Self-decelerating Permanent Magnet In-wheel Motor

With the increasing exhaustion of fossil fuel and environmental pollution caused by traditional fuel vehicles,electric vehicles have received extensive attention due to their advantages in energy conservation and their environmentally friendly nature.As one of the core components in electric vehicles,the electric motor drive system has become a research hotspot recently.Compared with the traditional centralized driving system like those in fuel vehicles and most electric vehicles,the unique wheel drive system eliminates the mechanical transmission device,increases the control freedom,and has a better development prospect.Based on the principle of magnetic field modulation,the Self-Decelerating Permanent Magnet in-Wheel Motor(SDPM in-Wheel Motor)can make the high-speed inner stator magnetic field and low-speed outer rotor magnetic field rotor synchronously.Besides,its simple structure and high power density make it ideal for electric vehicle wheel drive.In order to improve the torque response speed of SDPM in-Wheel Motor and improve its performance in electric vehicle drive system,this paper studies the Deadbeat-Direct Torque and Flux Control of SDPM in-Wheel Motor.First of all,the background and significance of this research is clarified.Then the development of SDPM in-Wheel Motor is reviewed.Because the electromagnetic characteristics of this kind of motor are similar to those of ordinary permanent magnet synchronous motor,control method of permanent magnet synchronous motor control is analysed,with more focus on direct torque control.Then,coordinate transformation principle of three-phase AC motor is introduced and mathematically model of SDPM in-Wheel Motor is established.Besides,motor parameter is measured for parameter-based control algorithm.Then,the derivation process of traditional Deadbeat-Direct Torque and Flux Control(DBDTFC)is given in this paper.The core drawback of DB-DTFC is its large amount of computation.Then the paper redesigns the DB-DTFC algorithm and proposes an AdvancedDB-DTFC(A-DB-DTFC)algorithm,so that the stator voltage reference can be obtained by solving two linear equations,which simplifies the algorithm.Furthermore,due to the one period delay in the digital control system,a stator current observer and a stator flux observer are designed to compensate the delay.The stator current observer is based on the numerical integration of motor model and cooperates with error feedback.The stator flux observer is based on the system state space model.Because the system is observable,the stator flux linkage of the next control period can be predicted.Finally,based on the MATLAB/Simulink platform,the simulation model of the A-DBDTFC system of SDPM in-Wheel Motor is built,and based on TMS320F28335 DSP,experiment is implemented.The simulation and experimental results show that the current and flux observer can predict the actual value in the next control period.The A-DB-DTFC system can realize the electromagnetic torque deadbeat control when the parameters are accurate.When the parameters are inaccurate,the system can also maintain a fast torque response.