A Battery/Ultracapacitor Hybrid Energy Storage System - Matlab Simulink Project
Renewable energy sources (RESs) have been extensively
integrated intomodern power systems tomeet the increasing
worldwide energy demand as well as reduce greenhouse gas emission.
As a result, the task of frequency regulation previously provided
by synchronous generators is gradually taken over by power
converters, which serve as the interface between the power grid
and RESs. By regulating power converters as virtual synchronous
generators (VSGs), they can exhibit similar frequency dynamic response.
However, unlike synchronous generators, power converters
are incapable of absorbing/delivering any kinetic energy, which
necessitates extra energy storage systems (ESSs). Nonetheless, the
implementation and coordination control of ESSs in VSGs have
not been investigated by previous research. To fill this research
gap, this letter proposes a hybrid ESS (HESS) consisting of a battery
and an ultracapacitor to achieve the power management of
VSGs. Through proper control, the ultracapacitor automatically
tackles the fast-varying power introduced by inertia emulation
while the battery implements the remaining parts of a VSG and
only compensates for relatively long-term power fluctuations with
slow dynamics. In this way, the proposed HESS allows reduction
of the battery power fluctuations along with its changing rate. Finally,
experimental results are presented to validate the proposed
concept.