Robust position control of induction motor drives

This paper presents the experimental validation of an efficient position control scheme, based on the speed smooth VSC (Variable Structure Control) algorithm with an adaptive gain for the indirect vector control of the induction motor. The position loop is regulated with a Proportional controller and the speed loop incorporates a smooth and adaptive VSC regulator, while in the current loops incorporates the SVPWM (Space Vector Pulse Width Modulation) with the PI (Proportional Integral) controllers. This position control scheme for induction motor, maintains the main characteristics provided for the VSC algorithm: fast response and good rejection of uncertainties and measurement noises. The speed VSC provides an electromagnetic torque without the undesirable chattering phenomenon that usually appears in the traditional VSC schemes, because it uses an adaptive sliding gain with a smoothed control law, based on saturation function. The presented position scheme has been tested using various simulations and real experiments, and in the proposed case, with and without unknown load, taking into account the parameter uncertainties and measurement noise in the loop signal, the rotor speed and the stator current.