Position control of a vector controlled induction machine using Slotine´s sliding mode control approach

The paper demonstrates that invariant regulator and superior servo performance can be obtained, compared to a fixed-gain controller, using Slotine´s method of sliding mode control for position control of a vector-controlled induction machine. The position control scheme consists of a standard indirect vector-control implementation for torque control, without rotor resistance identification, with an outer sliding mode position control loop. An important feature of this technique is that robustness to parameter variation can be achieved, and stability assured, through the control law design, assuming the bounds on the parameter variations are known. The resulting nonlinear control law is computationally simple. These improvements are practically demonstrated for variations in the load inertia and mismatch between the actual rotor resistance and the vector controller´s assumed value