Abstract
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.
Highlights
Microgrid systems have been developed in both grid-connected and islanded modes, to provide a simpler way to assimilate distributed generation into power grids, allow more reliable supply, and allow local generation and demand to match, reducing transmission losses [1]
DC microgrids have become an attractive technology in modern electrical grid systems as a natural interface with renewable energy sources, electric loads, and energy storage systems; the number of power electronic converters interfacing the sources, microgrid, and load is reduced, when compared to the same AC microgrid systems [2–4]
At the heart of microgrids are the power electronic interfaces that link the sources to the microgrid, and several different control methods have been proposed for these interfaces [5–8], allowing for autonomous or centralised control of the microgrid, with different layers of control to achieve varying goals, relating to grid stability, voltage regulation, energy availability, and cost
Summary
Microgrid systems have been developed in both grid-connected and islanded modes, to provide a simpler way to assimilate distributed generation into power grids, allow more reliable supply, and allow local generation and demand to match, reducing transmission losses [1]. Further improvement in reliability and efficiency of electrical grids can be achieved by utilising the DC distribution in microgrid systems. Academic and industrial interest continues to develop in direct peer-to-peer energy trading which entails direct coordination among distributed energy producers and consumers, or those who can be described as a combination of the two so-called prosumers [11–12]. This cooperation between energy producers and consumers can maximise energy utilisation and reduce the need for storage, contributing in turn to reducing unit energy cost and carbon footprint [11]. This paper will describe the proposed multi-tier DC microgrid concept, developing a universal control scheme to operate the system and demonstrating its operation through a series of simulations, including peer-to-peer energy transfer
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
