FEEDBACK LINEARIZED INDUCTION MOTOR CONTROL USING FOSMC AND SLIDING MODE-MRAS ESTIMATOR

Abstract

The Model of induction motor indicates that it is nonlinear, MIMO and strongly coupled system. To control this nonlinear motor as a nonlinear system, application of IOFL and sliding mode controllers are promising. Application of sliding mode controllers results the problem of chattering which is undesirable for electrical drive system. Here, this problem is tackled by using sigmoid function instead of signum. On the other hand, all states of squirrel cage induction motor are not easily accessible and use of mechanical speed sensor increases cost of the drive system. The proposed system eliminates the need of mechanical speed senor by employing combined Model reference adaptive system (MRAS) and sliding mode estimation technique which is known for robustness to model uncertainties and load disturbances. From simulation results carried out it is also observed that by using proportional integral derivative, sliding mode controller and fractional order sliding mode controller an overshoot of 9.5211%, 0.4753% and 0.3674% are found respectively for 120 rad/sec speed reference. FOSMC shows best robustness for load torque disturbance having a minimum speed drop of 1.1757% while PID and conventional integer order SMC have higher speed drop of 5.5982% and 1.388% respectively at the instant 10 Nm is applied. Applica tion of sliding mode- model reference adaptive speed estimator gives good estimate of rotor flux with mean absolute percentage error of 0.2584% and speed with mean absolute percentage error of 0.1767%