Asymmetric Topologies and PWM Modulation
Strategy for Low-Cost and High-Quality
Single-Phase Multilevel Inverter
Choi, Woo-Seok
Department of Electrical Engineering
Graduate School of Chonnam National University
(Supervised by Professor : Park, Sung-Jun)
(Abstract)
Recently, the development of the renewable power industry has been
accelerating due to climate change induces to make an effort is the
greenhouse gas reduction, and as industrial growth increases the demand
for electric power and the electricity generation costs, it has been
changing to improve efficiency for power industry structure, and have
necessary to develop suitable power converter. Power industry structure
has been changing to system minimize demand variation in order to
improve grid stability, with low cost. It appears that distributed powers
based on renewable power are spreaded over the society at large. In order
to fulfill the role of distributed power based on renewable power would be
advantageous, using the small size of the distributed power, for grid in
stabilized respect. In such cases, many power transmission applications
have used the multilevel inverter because the power quality of the
renewable distributed power is very important. The multilevel inverter has
the advantage of being to generate the output voltage with lower loss and
lowr EMC(Electro-Magnetic Compatibility) owing to its low dv/dt stress.
The conventional multilevel inverter topologies can include the diode
clamped multilevel inverter and flying capacitor multilevel inverter,
cascaded multi-cell H-bridge inverter topology. The conventional inverter
topologies have a series connection of switch groups, and are usually
applied to high power applications with high input/output voltage.
However, these topologies have a large increase in the number of
switches as the output voltage level increases, and thus are not suitable
for the single-phase grid or low voltage applications.
The single-phase multilevel topology has the advantage of reducing the
number of switches due to lower input/output voltage compared with the
conventional multilevel inverter topology. Recently, research into
single-phase multilevel inverters has been active as a way to improve
power quality. The single-phase multilevel inverter topologies are
classified as multilevel inverter based on H-bridge and multilevel inverter
based on Half-bridge. This single-phase multilevel inverter based on
H-bridge is needed to turn on more than two switches on the one
voltage level.
However, the single-phase n-level inverter based on H-bridge is comprised of a smaller number of switches than 2n, and thus a switch is used on more than two output voltage levels.
LINKS
PART1: http://www.mediafire.com/file/ox76ybclip3mphq/SINGLE_PHASE_MULTILEVEL_INVERTER.pdf
PART2 :
http://www.mediafire.com/file/nbqmzi3nas5nkdg/SIMULATION_AND_HARMONIC_ANALYSIS.pdf
