Page 347 - Renewable Energy Devices and System with Simulations in MATLAB and ANSYS

334 Renewable Energy Devices and Systems with Simulations in MATLAB and ANSYS ®
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+
C DC
AC L
Energy
V DC storage

C DC
–
(a)

+
AC L
C DC
Energy
V DC storage

–

(b)

+
C DC
AC L

V DC Energy
storage
C DC
–
n
(c)

FIGURE 13.15 Three-phase bidirectional boost converter topologies: four-switch (a), six-switch H-bridge
voltage source converter (b), and four-wire (c).

13.5.2 Non-Isolated DC/DC Converters
Bidirectional DC/DC converters can be classified into two main groups as isolated and non-isolated.
Non-isolated versions are simpler in design, control, and implementation and may have lower cost
and better efficiency. Nevertheless, isolated converters are absolutely required in certain applica-
tions. The applications of bidirectional DC/DC converters include renewable energy systems
integrated with ESS (as an energy buffer to smooth and mitigate output power fluctuations), line
interactive UPS (interface between ESS and DC link), PHEV, and EV (to connect the ESS to the
electric traction drive system).
An important requirement for DC/DC converters used in ESS applications is a high voltage ratio
with low input current ripple, such that the ESS lifetime is not negatively affected due to the ripple itself
[73, 74]. Several configurations have been published [75–78], including basic converter topologies of
the Cuk, SEPIC/Luo, half-bridge (HB) type, and more complex configurations, such as multiphase
interleaved, cascaded HB, and, more recently, multilevel bidirectional DC/DC converters [79–82].