Modular multi-terminal flexible DC micro-grid network and hierarchical control method thereof

The invention discloses a modular multi-terminal flexible DC micro-grid network, which comprises a DC bus, a controllable module, an uncontrollable module and a large grid of a multi-terminal flexibleDC micro-grid. The controllable module comprises one or more controllable distributed power sources, a battery energy storage system, a DC load and an AC load, wherein each controllable distributed power source is incorporated into the DC bus through a distributed power source grid connection device, the battery energy storage system is connected to the DC bus through a stored energy grid connection device, the DC load is directly connected with the DC bus, and the AC load is connected with the DC bus through an AC load grid connection device. The control objective is simplified as the bus voltage control of the DC micro-grid, and thus, the control mode can be selected easily. The micro-grid is modularized and changed from a previous 'designed micro-grid' into an 'assembled micro-grid', and the DC micro-grid is d