基于低压直流配电网并网的并离网一体光储发电系统研究

Research on a PV-energy storage system with integration of grid-connection and disconnection modes based on low-pressure DC distribution network

为解决弱电网条件下交流并网存在的并网逆变器稳定性问题,提出一种基于低压直流配电网并网的并离网一体光储发电系统。该系统包括光伏组件、公共直流母线、储能系统、低压直流配电网、交直流负载和多个功率变换器,根据光伏、储能、配电网的3级能量管理策略,分别采用不同的功率变换器控制策略,系统可分为4种工况:孤岛运行,光伏发电;并网运行,光伏发电;孤岛运行,储能供电;并网运行,电网供电。在Matlab/Simulink中对各工况进行仿真,结果验证了所提系统的正确性,为基于低压直流并网的并离网一体光储发电系统的实际应用提供了理论参考。

In order to keep the stability of the inverters connected to a weak grid,a PV-energy storage system with integration of grid-connection and disconnection modes based on low-voltage DC distribution network is proposed.The system includes PV modules,common DC bus,energy storage system,low-voltage DC distribution network,AC/DC loads and multiple power converters.According to the three-level energy management strategy for PV generation,energy storage and distribution network,different power converter control strategies were taken.The system has four working modes:isolated operation with PV power generation,grid-connected operation with PV power generation,isolated operation with battery power supply,grid-connected operation with grid power supply.Each working condition was simulated in Matlab/Simulink.The results verify the correctness of the proposed system,which provides a theoretical reference for the practical application of the PV-energy storage system with integration of grid-connection and disconnection modes based on lowvoltage DC distribution network.