基于自适应下垂控制的直流微网群协同控制策略

Cooperative Control Strategy of DC Microgrid Clusters Based on Adaptive Droop Control

  • 摘要: 在直流微网群中,多个差异性及波动性大的微网接入会影响微网群的稳定运行。针对这一问题,首先提出一种自适应下垂控制策略,使储能根据自身的荷电状态(State of charge,SOC)与容量进行功率分配,有效地避免了储能电池的过充与过放,同时加入线路阻抗与压降补偿环节,消除了线路阻抗引起的功率均衡偏差和下垂控制引起的电压偏差。其次,构造微网自治、群间互济、群网协同三种运行模式稳定切换的协同控制策略,在其中引入协同系数,同时与改善后的下垂控制相结合,使电压越限时得以并网,从而保证微网群的稳定运行。最后,通过三种典型场景的试验验证所提群间协同控制策略的有效性。

     

    Abstract: In DC microgrid clusters, the access of multiple microgrids with large differences and fluctuations will affect the stable operation of the microgrid clusters. To solve this problem, first of all, an adaptive sagging control strategy is proposed. Energy storage can be controlled according to its own state of charge(SOC) and capacity are used for power distribution, which effectively avoids overcharge and overdischarge of energy storage battery. Meanwhile, line impedance and voltage drop compensation are added to eliminate power balance deviation caused by line impedance and voltage deviation caused by droop control. Secondly, the cooperative control strategy of three operating modes, namely, autonomy of microgrid, mutual aid between clusters and collaboration of clusters and grid, is constructed, in which the cooperative coefficient is introduced, and combined with the improved droop control, the voltage exceeds the limit can be connected to the grid, so as to ensure the stable operation of microgrid clusters. Finally, three typical scenarios are used to verify the effectiveness of the proposed cooperative control strategy.

     

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