Meng, Lexuan

Project title: Tertiary Control and Energy Management System in Microgrids

PhD period: 2012.10.01 – 2015.09.30.
Section: Power Electronic Systems
Research Programme: MicroGrids
Supervisor: Josep Maria Guerrero Zapata
Co-Supervisor: Tomislav Dragicevic
Contact information

Collaborator: China Scholarship Council.
Funding: China Scholarship Council and scholarship from the Dept. of Energy Technology.


A MicroGrid is a local grid formed by a number of distributed generators, energy storage systems and loads, with proper coordinated controllers, which is able to operate in both grid connected and islanded modes.

In order to standardize the operation and functions of microgrids, hierarchical control has been proposed recently. Functionally, the microgrid, in a similar way as the main grid, can operate by using the following three main hierarchical control levels:

a. Primary control is the droop control used to share load between converters.
b. Secondary control is responsible for removing any steady-state error introduced by the droop control.
c. Tertiary control concerning more global responsibilities decides the import or export of energy for the microgrid.

As the top level control, tertiary control takes care not only of the energy and power flows, but also of the power quality at the point of common coupling (PCC), e.g. low voltage ride-through capability. Furthermore, tertiary control exchanges information with the distribution system operator (DSO) in order to make feasible and to optimize the MicroGrid operation within the utility grid.

Energy management system of Microgrid (EMS-MG) plays an important role to ensure the stable and economic operation of Microgrid, meanwhile to keep the balance between the power production and power consumption and make the most use of renewable generation systems and maximize overall energy efficiency in the Microgrid. However, the EMS-MG faces new challenges because of the unique features of the Microgrid, such as the different characteristics of multi-generators, bidirectional power flow, the fluctuation and complement of primary energy and the versatile infrastructures of the Microgrid.


Publications in journals and conference papers may be found at VBN.