Advanced control for wind energy conversion systems with flywheel storage dedicated to improving the quality of energy

Abstract

In this article presents two techniques of commands DTC (direct torque control) and DPC (direct power control) applied in the system of converting wind energy with storage. The wind generator used is based on a double fed induction generator (DFIG) where the stator is linked directly with the network and the rotor is connected to the network through the power converter. The flywheel energy storage system (FESS) based on a flywheel, an induction machine (IM) and an electronic power converter is associated with the wind generator via the DC bus. The two converters side DFIG and the (FESS) are controlled by the DTC. The three-level converter side electricity grid which ensures constant DC bus voltage is controlled by the DPC, in order to mitigate the wave quality problems. In the literature, this control strategy has been frequently used for the two levels converter. The direct control of these systems has a purpose of eliminating the block of pulse width modulation and loops of regulations internal controlled variables, which gives a faster response. The use of switching table makes the system more efficient from the technical and economic view. A maximum power tracking technique «Maximum Power Point Tracking» (MPPT) and a pitch angle control strategy are presented. The model of the complete system is developed in Matlab/Simulink/to analyze from the simulation results the integration of wind chain to electric networks.