基于串联型分布式MPPT架构的直流微网系统无缝切换控制策略

为了提高直流微网系统中光伏单元的输出功率,以串联型分布式最大功率点跟踪(MPPT)架构代替传统的集中式MPPT架构,以光伏单元、蓄电池和负荷组成的直流微网系统为研究对象,分析了串联型分布式MPPT架构的控制策略。在不增加通信电路的前提下,提出了一种从MPPT模式到稳压降功率模式的无缝切换控制方法;为了保证直流母线电压稳定、串联型分布式MPPT架构安全运行以及延长蓄电池寿命,设计了直流微网系统的工况与能量管理控制策略。通过MATLAB/Simulink仿真分析表明:在环境失配情况下,采用串联型分布式MPPT架构可以大幅提升光伏单元的输出功率;所提控制方法可以有效地完成模式之间的无缝切换;所设计的系统能量管理控制策略可以良好地协调各单元运行,实现系统安全、稳定、高效运行。

Seamless switching control strategy of DC microgrid based on cascaded distributed MPPT architecture

In order to improve the output power of PV(PhotoVoltaic) unit in the DC microgrid, the cascaded distributed MPPT(Maximum Power Point Tracking) architecture is used instead of the traditional centralized MPPT architecture. A DC microgrid consisting of PV units, batteries and loads is taken as the research object and the control strategy of the cascaded distributed MPPT architecture is analyzed. A seamless switching control method for PV unit from MPPT mode to voltage stabilization mode is proposed. In order to ensure the stability of DC bus voltage, the safe operation of cascaded distributed MPPT architecture and the extension of battery life, the working condition and energy management control strategies are designed. The simulation analysis in MATLAB/Simulink shows that, the cascaded distributed MPPT architecture can greatly improve the output power of PV unit in the case of environmental mismatch, the proposed control method can effectively realize the seamless switching among different modes, and the designed energy management control strategy can coordinate the operation of each unit very well and realize the safe, stable and high-efficiency operation of system.