Doctoral Dissertation
Multi Level Inverter System
using Dual Output DC-DC
Converter with High Gain
Department of Electrical Engineering
Graduate School, Chonnam National University
Ibadullaev Anvar
February 2021
Multi Level Inverter System using Dual Output
DC-DC Converter with High Gain
Ibadullaev Anvar
Department of Electrical Engineering
Graduate School Chonnam National University
(Supervised by Professor Park SungJun)
(Abstract)
Electricity has a weighty and an important impact on the social, industrial
and economic developments of countries around the world because it is an
essential ingredient of modern civilization. XXI century civilization depends
on constant accessibility of this wealth in order to continue the present
form of life and developing. Recently, with the development of green energy
producing technology, the use of renewable sources such that photovoltaic
arrays(PV), fuel cell sources, etc. have been increasing rapidly. Depending
on the new research report published by “Markets and Market“, the inverter
market is projected to grow from USD 12.8 billion in 2020 to USD 26.5
billion by 2025. The inverter market is likely to exhibit lucrative growth
potential during the forecast period. The growth of the inverter market is
expected to be driven by continuosly rising number of industrial and
household solar rooftop installations.
This exponentially growth of the inverter selling segment can be
understood the entering of photovoltaic energy generation plants,
HEV(hybrid electric vehicles) and electric vehicles charging stations that has
brought new opportunities and challenges in the power electronics industry,
especially in terms of the research and development of the main traction
three phase AC motor drives. The multilevel inverter structure based
topologies gives the OK to these vehicles to hold out to high voltages and
power levels without using bulky and hard transformers. And also, the
limited installation spaces of the HEVs have also led to the requirement for
small size and power efficient inversion devices. Among end users, the
residential segment held the largest share of the inverter market in 2019.
Continuously rising electricity bills, coupled with supportive government
policies worldwide, have led to the increasing adoption of energy
conservation measures such as solar rooftop installations for controlling the
increased energy expenditure in residential applications. Countries such as
Japan, the United States, the Netherlands and Australia which are among
the prominent markets for residential rooftop solar installations, have widely
adopted solar inverters over conventional non-solar inverters. In addition,
countries such as Brazil, the United Kingdom, India and Mexico are
currently witnessing significant growth in the residential solar energy
market. In modern smart grid solutions, control technologies for the
consumption can response based on information about the electricity
generation and transmission system and prices in an automatic way to
improve the performance and reliability of the system. Demand for better
designed hardware topology and controllers is constantly rising as the
renewable energy market continues to sharply grow. In a typical residential,
or small factory utility photovoltaic arrays are connected in series, in
parallel or mixed type to form high DC voltage bus to can connect to
DC-AC inverter, which then is connected directly to single or three phase
AC Grid. Using renewable power generation systems established with step
up dc-dc converters is being popularized because of the rising demand of
zero pollution and eco friendly renewable energy sources. In this study, a
new constructed multi level inverter system using dual outptut DC–DC
converter was proposed to match a low DC voltage output sources, such as
photovoltaic source or fuel cell systems with single phase AC grid bus
lines. When comparing to other conventional multi level inverters, the
proposed multi level inverter has a decreased number of the
semiconductors, can create higher quality power with lower THD values,
has decreased and balanced voltage stress for dual output dc-dc converter
DC capacitors. The proposed topology requires a single DC source. In final,
the output viability of the proposed topology is described by simulation and
experimental results with 1 kW hardware prototype. While comparing to
another counterparts step-up DC–DC converters, the proposed Multi Level
Inverter System using Dual output DC-DC converter with high gain performs
higher gain and has lower inductor current ripple and lower drain-source
voltage stress for power semiconductors. Also the proposed dual output
DC-DC converter with high gain creates dual DC voltage output and voltage
stresses for the active and passive components have been decreased which
is the main superiority of the proposed topology. Steady state analysis in
CCM(continuous conduction mode) of the proposed topology is detailly
performed. And also the laboratory prototype of the proposed topology is
assembled using low voltage low power switches and low
capacitors. Output DC voltage and AC current control algorithm is performed
by employing DSP TMS320F28069F controller based control board. The
performance of the proposed topology is verified by a lot of simulation and
experimental results.
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