Modeling and Comparison of Unbalanced Load Compensation Methods in DFIG Systems Based on Mechanical Constraints

In remote areas, stand-alone wind energy conversion systems (WECSs) are significantly employed to supply the power of local loads. In such conditions, the longevity problem of WECSs is a necessary problem. Therefore, it is necessary to investigate the interaction between electric and mechanical parts of stand-alone WECSs. In the literature, the longevity problem of WECSs has rarely been studied. This paper investigates the interaction between electric and mechanical parts of the doubly- fed induction generator (DFIG)-based WECS in stand-alone mode. In this paper, the matter of compensating a non-linear load from the point of mechanic tension problem on the DFIG shaft has been investigated. To this end, the application of the dynamic voltage restorer (DVR) connected to the stand-alone DFIG is presented to compensate non-linear load. The efficiency of the proposed method is compared with the harmonic rejection technique. The simulation results reveal that the proposed method negates the need for maintenance in the long term and increases the longevity of DFIG.