A proposed strategy for power optimization of a wind energy conversion system connected to the grid

Keywords: Wind turbine Doubly fed induction generator Optimization Matrix converter Power control Sliding mode control a b s t r a c t Many strategies have been developed in last decade to optimize power extracted from wind energy conversion system where many of them can produce only 30% more than the rated power. With the considered strategy, the generated wind power can reach twice its nominal value using a fast and reliable fully rugged electrical control. Indeed, by employing a suitable control technique where the produced power in super-synchronous mode is derived from both the stator and the rotor. Also, the rotor provided power in this case grows up 100% comparing to stator rated power. However, this solution permits to maintain the wind energy conversion system operation in its stable area. The considered system consists of a double fed induction generator whose stator is connected directly to the grid and its rotor is supplied by matrix converter. In this paper, the sliding mode approach to achieve active and reactive power control is used. This latter is combined with de Perturbation and Observation Maximum Power Point Tracking used in the second operation zone. The obtained simulations results are assessed and carried out using Matlab/Simulink package and show the performance and the effectiveness of the proposed control. Due to its advantages, wind energy attracts many researchers in the last decade. Some authors focused their research on problems relating to the storage of this energy like John and David who led a study on probabilistic energy storage and its use with intermittent renewable energy [1]. Xiaosong et al. made comparative study of three electrochemical energy buffers applied to a hybrid bus Powertrain with optimal sizing and energy management [2]. Others are more interested in improving the quality of energy produced and injected into the grid and working on models and various control techniques. In [3], the authors propose a model to control a wind turbine associated with a flywheel energy storage system to improve the quality of power injected into the grid. In [4], a grid power flux control of a variable speed wind generator which consists of a doubly fed induction generator is investigated. A new control strategy for small wind farm is proposed in [5] to improve supplying reactive power and transient stability. To avoid strong transients in the turbine components, a cascaded nonlinear controller is designed in [6] for a …