A Multi-Agent Based Distributed Economic Droop Control for Islanded Microgrid

传统下垂控制一般按照额定容量分配有功功率，未考虑分布式电源的运行成本，易引起微网运行成本偏高，针对这一问题，本文基于MAS理论提出了一种分布式经济下垂控制模型，实现了微网的最优经济运行。该模型采用两层控制结构，上层是基于MAS的通信网络，下层是基于下垂控制的微网。基于此模型，根据等微增率准则，提出分布式经济优化算法对目标函数进行求解，进而优化下垂控制的参考频率，实现了分布式电源按成本经济运行。该算法只需局部通信，在迭代过程中能够不会打破系统原有的功率平衡，且能够克服容量越界问题，具有较好的鲁棒性。通过算例分析了所提算法考虑出力越界以及环境和负荷同时波动情况下的收敛情况，仿真结果验证了所提算法的有效性。 The active power is distributed proportionally to capacities of DGs in traditional droop control, which may result in the high operation cost because of no considering the cost. Based on this problem, a novel distributed economic droop control model based on the multi-agent theory is proposed for islanded microgrids. The proposed control model consists of two layers, where the top layer is a multi-agent based communication network, and the bottom layer is a droop controlled microgrid. Based on the model, a distributed economic optimal algorithm is proposed in terms of the equal incremental cost criterion. Then the frequency reference is optimized and the economic operation of DGs is achieved. In the algorithm only the local information is exchanged and the system power balance won’t be broken at the same time. Finally, case studies are carried out to test the performance, in which cases with capacity constraints are considered when both environmental and load demand fluctuate. Simulation results demonstrate the effectiveness of the proposed algorithm.