低压直流微电网的能量管理与协调控制是保证其可靠运行需要解决的关键问题之一。基于直流母线电压信号的传统控制方法在不同工作模式将引起直流母线电压存在偏差,对恒功率负载造成不利影响,进而引起系统不稳定。针对这一问题,提出一种基于本地信息的能量管理和协调控制方法。详细分析并网运行、变流器限流运行以及孤岛运行模式下的能量管理、切换条件和协调控制方法。在系统孤岛运行模式下采用一种开环桨距角控制方法并结合恒压控制,消除直流电压波动,提高电能质量和系统稳定性。最后进行仿真研究,仿真结果验证了所提出方法的有效性。
The energy management and coordinated control of low voltage DC (LVDC) microgrid is one of most important issues for ensuring the system reliable operation. The traditional control methods based on the DC bus voltage signal (DBS) would give rise to DC voltage deviation under different operation conditions, which have an adverse impact on constant power load (CPL) within LVDC microgrid, and then lead to system instability. An energy management and coordinated control method based on local information was proposed. The energy management modes, switching conditions and coordinated control method were analyzed in detail under grid-connected operation, converter current-limit and islanding operation conditions. An open-loop pitch angle control method with constant voltage control could eliminate DC-link voltage fluctuation, enhance power quality and system stability under islanding operation conditions. Finally, the effectiveness of proposed method was verified by simulation results.