What is DGs?
In distribution levels, many smaller renewable
generators (e.g. photovoltaic, fuel cells, micro hydro
etc.) will be connected to the networks. These are
called distributed generators (DGs) or distributed
energy resources (DERS).
What is microgrid ?
A microgrid is a cluster of loads and microsources
operating as a single controllable system that
provides power to its local area.
This paper proposes a method for power ﬂow control
between utility and microgrid through back-to-back
converters, which facilitates desired real and reactive
power ﬂow between utility and microgrid.
In mode-1, specified amount of real and reactive power are shared between the utility and the
microgrid through the back-to-back converters.
Mode-2 is invoked when the power that can be supplied by the distributed generators (DGs) in
the microgrid reaches its maximum limit. In such a case, the rest of the power demand of the
microgrid has to be supplied by the utility
Ritwik Majumder, Student Member, IEEE,
Arindam Ghosh, Fellow, IEEE,
Gerard Ledwich, Senior Member, IEEE,
Firuz Zare, Senior Member, IEEE
Date of publication :2 MAY 2010
To improve power sharing techniques in microgrid with
converter interfaced sources
To improve power management system and reliability of the
To achieve superior power sharing in rural network with high
To facilitate load frequency control of the microgrid and a
smooth transition between grid in connected
Stability of grid system is achieved to great extent
The power quality at consumer premises can be improved
Economical based operation
One of the major advantages of the back-to-back converter
connection is that it can provide isolation between the utility and
the microgrid, both for voltage and frequency fluctuations.
FUTURE SCOPE OF WORK
Protection of back to back converters in case of fault can be investigated
The improvement can be achieved by selection of more appropriate input
signals or controller gains
Modified drop control can be derived for frequency dependent load
Communication can be used to correct the reference quantities
The reliability in a microgrid can be improved with the application of back-to-
back converters for bidirectional power flow
Power sharing can be achieved with dropping output voltage angels of the converters
The quality of distributed generation can be improved significantly by proper reference generation
for the DG’S
The reliability in a microgrid can be improved with the application of back-to-back converters
A low band width communication can also improve power sharing significantly
 IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems,"
Std 1547-2003 , vol., no., pp.0_1-16,
 R. H. Lasseter, "MicroGrids," in Power Engineering Society Winter Meeting, 2002. IEEE, 2002,
pp. 305-308, vol.1.
 M. Milosevic, P. Rosa, M. Portmann, and G. Andersson, "Generation Control with Modified
Maximum Power Point Tracking in Small Isolated Power Network with Photovoltaic Source," in
Power Engineering Society General Meeting, 2007. IEEE, 2007, pp. 1-8.