Project title: Coordinated Control and Management of Distributed Energy Storage Systems for Microgrids
PhD period: 2013.04.01 – 2016.03.31. (has been prolonged till 2017.03.19.)
Section: Power Electronic Systems
Research Programme: Microgrids
Supervisor: Josep M. Guerrero
Co-Supervisor: Juan Carlos Vasquez
Collaborator: District University of Bogotá, Colombia.
Funding: Scholarship from District University of Bogotá, Colombia, and Dept. of Energy Technology.
A MicroGrid is an aggregation of Distributed Energy generators, loads and energy storage systems which should operate as a single controllable system. Therefore, a MicroGrid requires flexible and coordinated operation for all its units in order to ensure uninterruptible energy supply to the loads, as well as high power quality for its both operation modes (grid-connected or islanded). However, the increasing penetration of renewable energy sources such as wind and solar energy has increased the concern about energy management in MicroGrids. To be more precise, intermittence of renewable energy sources may cause energy unbalances that affect the power quality in a MicroGrid. Apart from that, the effects of sudden load fluctuations and changes on load demand should be mitigated for getting higher power quality in MicroGrid.
In that sense, storing energy is absolutely required to guaranty reliability, security and high power quality in MicroGrids with the presence of highly-variable energy sources and loads. However, a single storage unit is not enough; it is necessary to have distributed energy storage units for increasing the power quality in a MicroGrid. In fact, different kinds of energy storage units are commonly used into a MicroGrid (battery, ultracapacitor, flywheel, etc.). Besides, even if the energy storage system uses batteries only, differences at the state of charge require a coordinate management at the energy storage system.
The main objective of this project is to develop new control strategies for management of distributed energy storage units in a MicroGrid. A proper energy management scheme will be obtained in order to compensate the effects of load fluctuations and the intermittency of renewable energy generators. Additionally, it is expected to obtain proper local controllers for all the energy storage units, ensuring an adequate active and reactive power flow under grid-connected and islanded operation. Therefore, Cooperative control strategies will be conceived, regarding differences at the energy storage units and the state of charge at the energy storage units in order to define the set point of each unit.
Publications in journals and conference papers may be found at VBN.