Adaptive Control Scheme for PV Based Induction Machine

An adaptive control scheme for maximum power point tracking of a single-phase grid-connected photovoltaic system is presented. The difficulty on design a controller that may operate a photovoltaic system on its maximum power point (MPP) is that, this MPP depends on temperature and solar irradiance, ambient conditions that are time-varying and difficult to measure. A solution using an on-line sliding mode estimator is presented. It estimates three different parameters that depend on solar irradiance and temperature, eliminating the necessity of having any sensor for these environmental variables. It is capable of estimate time-varying parameters. A complete analysis was done taking into account the non-linearity’s showed by the closed-loop system. An adaptive law was found to substitute a perturbation bound and also to eliminate possible chattering due to the discontinuous controller term. Computer simulations are presented to show the good performance of the controller. The controller detects the deviation of the actual trajectory from the reference trajectory and corresponding changes the switching strategy to restore the tracking. Prominent characteristics such as invariance, robustness, order reduction, and control chattering are discussed in detail. Methods for coping with chattering are presented. Both linear and nonlinear systems are considered The proposed concept can be implemented to adaptive control scheme for induction machine using Matlab/Simulink software.