Sensorless vector control of SVPWM inverter fed induction machine using MRAS-sliding mode

Abstract

One of the most important technologies for electric vehicles is the drive control technology which does not require a position or speed sensor. In a sensorless vector controlled induction machine, the speed must be estimated from the system measurements. Model Reference Adaptive System (MRAS) based techniques are one of the best methods to estimate the rotor speed due to its performances and straight forward stability approach. The performance of the traditional rotor flux MRAS with PI controller deteriorates due to integrator drift and sensitivity to current measurement noise. Practically, system tuning is difficult and may yield under damped responses. In this paper, a new robust MRAS scheme based on sliding mode technique to estimate the rotor speed of a sensorless vector controlled induction machine is proposed. Further, a space vector pulse width modulated (SVPWM) voltage source inverter is used to feed the induction machine rather than the traditional sinusoidal PWM inverter for the simulation. The drive system with the proposed adaptive mechanism is simulated by MATLAB/Simulink to verify the principles of the technique and compared its performance with that of PI controller.