Design and analysis of single phase 7-level cascade full bridge inverter with half impedance source

Energy is an essential and indispensable resource used in every field. While people used the energy produced by fossil resources more in the past, nowadays, the increasing prices of fossil fuels, the emergence of environmental awareness due to environmental pollution, the targets of reducing carbon dioxide emissions in the automotive sector, the depletion of fossil energy reserves in general, technological developments, and increasing energy demand have directed people to renewable energy sources. Renewable energy sources are solar, geothermal, wind, biomass and hydroelectric. With the increasing popularity of renewable energy production and electric vehicles, the applications and research studies of multi-level inverter-based power systems are constantly increasing due to the advantages of multi-level inverters and the demands for significant power scale/high voltage grid connection. Cascade multi-level inverter (CMLI) has many benefits when applied to the power system because it can increase the system efficiency and provide high voltage/high power grid output voltage without a transformer. However, in the traditional CMLI-based power system, each module is a buck inverter, and the DC-link voltage varies with the input voltage. Z source (ZS)/quasi-Z source (qZS) CMLIs (ZS/qZS-CMLIs) can overcome the disadvantages mentioned above of traditional CMLI by combining the ZS/qZS network and the H-bridge module through the buck/boost and inversion of the ZS/qZS inverters (ZSI/qZSI) in a single stage. In this thesis, a half-impedance source, full bridge cascade 7-level inverter circuit is designed and its simulation analysis is done in Matlab/Simulink environment. The designed inverter has the capacity to produce the desired output voltage by adding or removing modules with its cascade structure. Being a half-impedance source inverter has provided an efficient, low-cost and size advantageous inverter that can increase/decrease the voltage at the output in a single step. In addition, being a multi-level inverter will ensure that the output voltage is close to the sinusoid, thus reducing the size of the filter to be used at the output.