Sensorless Vector Control System For Induction Motor In EV

Currently, under the background of worldly energy crisis and the seriousenvironmental pollution caused by the automobile exhaust, the world’s majordeveloped countries are committed to the research and development of the electric car.The induction motor is cheap and it has compact structure. So it is widely used in theelectrical vehicle driving systems. In order to reduce the driving part of the electricvehicle, and to reduce its complexity, and also to improve the reliability of the system,induction motor speed sensorless vector control system has become the focus ofattention of the people. For speed sensorless vector control system, the center problemis to determine the direction of the magnetic field accurately. Realizing the accurateflux observation in wide speed conditions is extremely important to improve thetorque’s accuracy and stability in the drive system of electric cars. In order to solvethe problem, two sensorless vector control systems, which are based on the full orderflux observer, have been designed in this paper.Firstly, the principle of the two full order flux observers is analysed respectively,and the mathmatical models of the observers are derived. Then the simulation modelsof the systems are established with Maltab/Simulink environment, and do thesimulation under different conditions. Secondly, software of the sensorless system isdesigned and the experiment is done on the platform based on TMS320LF2407whichis produced by TI company. According to the realization of the two kinds of full orderflux observer and parameter adjustment, this paper give an in-depth discussion andanalysis, and we get a lot of experimental data and clear experimental results.Theoretical analysis and simulation experiment show that, both of the two kindsof full order flux observer can observe the magnetic field accurately. On the basis ofthat, the speed sensorless vector control system works smoothly. They can be used inactual control scheme, and meet the requirements of the electrical cars’ motor drivesystem.