Control strategy of wind turbine based on permanent magnet synchronous generator and energy storage for stand-alone systems
This paper investigates a variable speed wind turbine based on permanent magnet synchronous generator and a full-scale power converter in a stand-alone system. An energy storage system(ESS) including battery and fuel cell-electrolyzer combination is connected to the DC link of the full-scale power converter through the power electronics interface. Wind is the primary power source of the system, the battery and FC-electrolyzer combination is used as a backup and a long-term storage system to provide or absorb power in the stand-alone system, respectively. In this paper, a control strategy is proposed for the operation of this variable speed wind turbine in a stand-alone system, where the generator-side converter and the ESS operate together to meet the demand of the loads. This control strategy is competent for supporting the variation of the loads or wind speed and limiting the DC-link voltage of the full-scale power converter in a small range. A simulation model of a variable speed wind turbine in a stand-alone system is developed using the simulation tool of PSCAD/EMTDC. The dynamic performance of the stand-alone wind turbine system and the proposed control strategy is assessed and emphasized with the simulation results.