Universal droop controller for DC-DC converter interfaces onto a modular multi-tiered DC microgrid

Microgrids are usually based on single voltage levels, supporting a number of distributed generation sources and loads. This paper describes a multi-tier DC microgrid, with multiple voltage levels able to source and supply different power demands. A universal droop controller is developed for this multi-tier microgrid, able to connect uni- and bi-directional elements on to the grid. Simulations are used to demonstrate the functionality of the controller to allow autonomous load sharing based on decentralised control, with bi-directional power transfer between tiers to balance supply and demand at each level. Power can also be directly sent from one element of the microgrid to another, which is demonstrated through simulation, allowing for integration with future peer-to-peer energy trading systems.