Distributed energy storage system, photovoltaic generation and loads for an active power regulation

However, when the number of DGs increases, it becomes difficult to determine the bus voltage/frequency thresholds. Recently, an interesting active power control law based on modified droop method is presented in [۱], which takes into account both SoC, and available power in the ESS and renewable energy sources, respectively. Nevertheless, the switching actions of droop curves may trigger stability problems induced by sudden bus frequency changes in micro grids. In this paper, a decentralized autonomous active power control strategy compatible with a hierarchical control scheme is proposed for islanded AC microgrids composed of distributed ESS, PV systems, and loads. Based on the proposed bus signaling method, the coordination function of power regulation between micro-grid elements is achieved in a decentralized manner. Additionally, an optional centralized secondary control is defined to implement bus frequency recovery when/if the micro-island grid is required to reconnect to the power grid. The proposed independent active power control has several key advantages: ۱) the SoC keeps the ESS in a safe range, while efficiently using renewable energy from PV systems, ۲) the principle of active power control is simple and design-independent The control loop is internal. which can be easily implemented on top of conventional ESS and PV control systems without changing the internal loop structure, ۳) Coordinated distribution of active power relies on continuous and smooth bus frequency signaling to avoid sudden bus frequency changes. The proposed autonomous control strategy is our Kav development described in [۲], while a more complete description of autonomous active power control in the full range of SoC and its implementation considering primary ESS and PV system resources is given in this paper.

کلیدواژه ها:

photovoltaic systems ، energy storage system