Tracking network voltage based control of the microgrid mode conversion

Due to the large power fluctuation in the mode conversion of Mircogrid, the single energy storage is hard to support the balance of power quickly and stably, which makes the mode conversion not stable and influences the quality of power supply. To improve the performance of microgrid conversion, a new control strategy is presented in this paper. In hybrid structure of vanadium redox battery (VRB) and supercapacitor, the supercapacitor adopts vf control to follow up the network voltage and frequency while microgrid turns into the islanded mode, making sure the voltage and frequency of microgrid and the network synchronization. VRB adopts vf/PQ control to ensure power balance of microgrid operation. This control strategy can improve the conversion rate of microgrid and ensure the stability of microgrid system. The simulation results show that the hybrid energy storage can achieve the excellent performance.