Research On Direct Torque Control Of Permanent Magnet Synchronous Motor For Electric Sightseeing Vehicle

Electric sightseeing vehicle as a miniature,low speed pure electric vehicle,with environmental protection and energy saving,comfortable ride,simple operation,beautiful appearance characteristics,is widely used in campus,parks and some tourist attractions.Due to the limitation of the overall volume of the vehicle,in order to make the electric sightseeing vehicle have a larger riding space,the motor volume should be as small as possible.Compared with other motors at the same power,the permanent magnet synchronous motor(PMSM)has the advantages of small volume,high efficiency and large power factor,making it the first choice for the driving motor of the electric sightseeing vehicle.In order to better control PMSM to meet the requirements of electric sightseeing vehicles,the direct torque control technology(DTC)is used in PMSM,and the control method is improved to improve the stability of the control system in view of the problems in the operation of PMSM DTC control system.This paper first introduces the common motor of electric sightseeing vehicle and analyzes its advantages and disadvantages,and determines PMSM as its driving motor.The basic structure of PMSM and its mathematical models in different coordinate systems are analyzed.At the same time,DTC and vector control methods are compared and analyzed,and finally DTC is used to control PMSM.Secondly,the paper discusses the control principle of PMSM DTC system in detail,and establishes the system simulation model in the MATLAB environment.The simulation results show that PMSM DTC system has good dynamic and static performance,which can basically meet the needs of electric sightseeing vehicle drive motor operation.However,this system also has some disadvantages,that is,the PMSM DTC system has a large torque fluctuation at low speed.In addition,the PI regulator of the speed ring in the PMSM DTC system has a contradiction between the speed and overshoot,so it needs to be improved.In this paper,a method based on space vector modulation(SVPWM)and sliding mode control(SMC)is introduced to suppress the torque fluctuation at low speed of DTC.The simulation results also prove the reliability of the proposed method,so as to improve the stability of PMSM DTC system at low speed.Thirdly,for the problem that it is difficult to take into account the overshoot and rapidness of the speed ring PI regulator,this paper uses the active disturbance rejection technology(ADRC)to improve it,and uses the linear active disturbance Rejection control method(LADRC)to redesign it in order to simplify the parameters and retain its characteristics.On the basis of this theory,a SMC PMSM DTC system based on LADRC is formed by combining the above sliding mode control method.The simulation results show that the improved system can keep the ability of reducing torque ripple of the original SMC PMSM DTC system and effectively reduce overshoot,so as to ensure the stability of PMSM DTC used for electric sightseeing vehicles and improve the speed accuracy of the system during operation.Finally,the hardware and software of PMSM DTC system for electric sightseeing vehicle are designed,the principle and design diagram of hardware circuit in the control system are given,and the flow chart of software algorithm is described.Figure [108] Table [8] reference [88]...