Four Quadrant Operation of Field Weakened FOC Induction Motor Drive Using Sliding Mode Observer

Abstract

Field Weakening (FW) is applied in order to allow operation of variable speed induction motor drives at high speeds. Field Oriented Controlled (FOC) induction machine has the capability for easy field weakening and the full utilization of voltage and current rating of the inverter to obtain a wide dynamic speed range. In a sensorless FOC induction machine, the estimation of rotor speed is difficult in the high speed region. Model Reference Adaptive System (MRAS) based techniques are one of the best methods to estimate the rotor speed due to its better performance and unsophisticated stability approach. MRAS scheme based on Sliding Mode (SM) technique provides accurate speed estimation during operation in the FW region. In this chapter, operation of FOC induction motor with and without sensor using Sinusoidal Pulse Width Modulation (SPWM) and Space Vector Modulation (SVM) inverters are compared and assessed in terms of their performance in the FW region. Further, the four possible combinations of polarities of torque and speed in four quadrant operation of induction machine are analyzed. The drive system with the proposed adaptive mechanism is simulated by MATLAB/Simulink to verify the performance of the drive system.