考虑电网分时电价的直流微电网分层协调控制

Hierarchical Coordination Control for DC Microgrid Considering Time-of-Use Price

针对无通信条件下低压直流微电网的分布式控制,提出了一种考虑电网分时电价的分层协调控制策略,将储能单元的剩余充放电功率与电网电价相结合,通过比较电池的充放电成本和电网电价,采用低价购电、高价售电的策略,以降低系统的运行成本。该策略将直流微电网的控制系统分为3个层次。其中,底层变流器控制层和中层母线电压控制层能够在保持各单元控制结构不变的情况下,根据公共直流母线电压平滑调节各单元输出功率,实现直流微电网的分散自治运行;上层功率调度层通过获取交流电网侧的分时电价信息,改变并网DC-AC变流器的实时运行状态,从而充分利用储能单元的剩余功率,提高系统运行的经济性。该策略下,系统中各组成单元均采用分布式控制结构,在保证多个电压控制单元间功率合理分配的同时,实现变流器"即插即用"的功能。Matlab/Simulink仿真结果验证了所提控制策略的有效性。

For low-voltage DC microgrids, where DC bus signaling（DBS） are widely used as communication link for distributed control, a TOU-price-based hierarchical coordination control strategy was proposed in this paper. In this control strategy, energy storage system（ESS） depreciation cost was compared with electricity price, and ESS unit would deliver more discharging power at high price and absorb more charging power at low price. Therefore, residual power in ESS could be fully utilized. The proposed control architecture was divided into three levels. At primary converter control level and secondary bus regulation level, autonomous decentralized operation was implemented without any communication link. At tertiary power dispatch level, DC-AC converters could adaptively change their operation states by collecting real-time electricity price. Therefore, DC microgrid economy could be improved by making full use of residual charge/discharge power in energy storage units. In this strategy, each unit in DC microgrid not only could realize smooth transition between different operation modes upon DC bus voltage signal, but also had plug and play function. Finally, validity of the proposed control strategy was confirmed with Matlab/Simulink simulation.