Abstract

In this study, a coordinated droop control strategy of dual-source energy storage system with virtual coordinate transformation is proposed by researching on the operation characteristics of low voltage (LV) wind/photovoltaic hybrid microgrid, which is prepared with battery energy storage system (BESS) and super capacitor energy storage system (SCESS). Using virtual coordinate transformation-based droop control not only solves the coupling problem between active and reactive power of LV microgrid, but also enables a coordinated control on BESS and SCESS to achieve smooth handoff from grid-connected mode to isolated mode of LV microgrid for wind, photovoltaic and energy storage. Using PSCAD/EMTDC simulation software, the models of wind turbine system, photovoltaic generation system and dual-source energy storage system are established to form LV microgrid. The effectiveness and feasibility of the proposed control strategy are proved, and the choosing of droop factor of BESS and SCESS is analyzed by simulation.

Keywords: Dual-source energy storage system, LV microgrid, smooth handoff, virtual coordinate transformation.