A grid-connected variable-speed wind generator driving a fuzzy-controlled PMSG and associated to a flywheel energy storage system

In this paper, we propose a variable speed-wind energy conversion system based on a permanent magnetic synchronous generator (PMSG). A complete system model with multiple controllers is proposed and simulated. Two controllers are proposed and examined for regulating the current from the PMSG, the first is a simple PI controller and the second uses a fuzzy component to improve the tracking performance. A flywheel energy storage system (FESS) is associated to the proposed variable speed wind generator (VSWG). The FESS is linked at the DC bus stage in order to regulate the power supplied to the grid. In simple terms, if the generated power exceeds the demand, the excess is stored by the FESS for use when a shortage occurs. In this scenario, the VSWG is controlled to capture the maximum wind energy by means of the maximum power point tracking (MPPT) method. To maintain this operation as the turbine speed increases above the rated speed, we implement a pitch angle controller. The FESS is based on a squirrel-cage induction machine (IM) coupled to a flywheel. A controlled grid converter allows for the exchange of active and reactive powers with the grid. A proportional integral (PI) based grid connection is proposed that controls the current and voltage amplitudes as well as the frequency passed onto the grid. The aim of the converter control is to achieve a decoupled active and reactive power control suitable for operation at a unitary power factor. The dynamic model of the proposed system is simulated using the Matlab–Simulink package. The obtained results are presented and discussed to illustrate the performance of the overall proposed system.