Research On Key Technology Of Asynchronous Drive Vector Control System For EV Based On Sliding Mode Observer

With the development of social economic,the problem of energy shortage and environmental pollution become increasingly serious,electric vehicles become the direction for the future development of the auto industry.In the explosive development of electric vehicles of the present,how to improve the performance of electric vehicles is essential.The performance of the motor drive system,which is an important component of the electric vehicle power system,plays a decisive role in the performance of the vehicle,and is hot and difficult problems of the current academic research.This paper carry out research work around the technology of speed observation,torque observation,parameters identification in EV induction motor drive system.The main contents can summarize as follows:Firstly,a induction motor speed sensorless control scheme is designed,by the designing on a high order non-singular terminal sliding mode observer,not only the accurate observation of the back EMF is realized,but also the chattering disturbance resulting from the discontinuous control in sliding mode observer is inhabited very well.Meanwhile,parameters sensitivity analysis shows that the back EMF is robust to motor parameters.The speed observer is designed based on the observation of back EMF,and speed sensorless control is realized..Secondly,a torque closed loop control scheme is designed.Based on the accurate observation of back EMF,a flux sliding mode observer is constructed to achieve the observation of the rotor flux,then do cross product between rotor flux and stator current to get electric torque,realizing the torque closed loop control of induction motor,increasing tracking accuracy of torque command issued by the central control unit.The outstanding advantage of the rotor flux observer is that it has strong robustness to rotor resistance and magnetizing inductance.Thirdly,a rotor resistance and magnetizing inductance on-line identification scheme is designed.The observed rotor flux with strong parameter robustness is chosen as reference model,and current flux model is chosen as adjustable model to form an MRAS observer,realizing the on-line identification of rotor resistance and magnetizing inductance.Meanwhile,Aiming at the coupling problem between rotor resistance and magnetizing inductance,a decoupling scheme is studied to improve the identification performance.Fourth,The simulation model and experimental system of 15 kW induction motorare built,The simulation and experimental study on the design of speed sensorless control,torque closed loop control,parameter on-line identification are carried out.