Electric vehicle control for required transient torque by using improved direct torque control with space vector modulation

The most popular method to control induction motor torque and flux for electric vehicles (EVs) is direct torque control (DTC). DTC has some advantages like simple structure, fast response, independent control of moment and flux, strong robust structure, etc., but DTC is sometimes insufficient due to fluctuations in torque and current. Fluctuations can be minimized by adding space vector modulation (SVM) to direct torque control. This method leads to difficulties in controlling the electric vehicles while travelling on sloping roads. The reason is the transient load torque which is created by the slope of the road. Transient load torque over rides this control scheme as it can not be reached the desired value during the switching period. Therefore, a new control scheme for transient in torque is needed. Deadbeat control allows a rapid transition to the desired value by using the shortest step ranges. In previous studies DTC, DTC-SVM or deadbeat control scheme was used for induction motor control. In this thesis, DTC-SVM is used with the improved deadbeat control scheme and adapt it to the road condition for electric vehicles. Electric vehicle dynamic analysis, vehicle and motor mathematical modelling, torque-flux calculations, DTC-SVM control and deadbeat control was done. On the uphill roads, deadbeat control scheme results, torque effects, motor and vehicle speeds were observed. Simulations were done in MATLAB/Simulink and correctness of the model was proved.