DC-Transformer Modelling, Analysis and Comparison of the Experimental Investigation of a Non-Inverting and Non-Isolated Nx Multilevel Boost Converter (Nx MBC) for Low to High DC Voltage Applications

This paper mainly focuses on the analysis, DC-transformer modeling, comparison, and experimental investigation of a non-inverting and non-isolated Nx multilevel boost converter (Nx MBC) for low to high DC applications. Recently, numerous isolated and non-isolated DC-DC converter configurations have been addressed for low to high DC voltage conversion purposes, which is vital for several applications (e.g., renewable energy, medical equipment, hybrid vehicles, fuel cells, DC-links, multilevel inverters, and drive applications), by utilizing and modifying the structure of reactive elements (switched capacitors and switched inductor circuitry). Among all the switched reactive structures, voltage multiplier circuitry provides a feasible solution for low to high DC voltage conversion due to its flexible and modular structure, voltage clamping capability, reduced rating of components, and ease of modification. Non-inverting and non-isolated Nx MBC combine the features and structures of conventional boost converters and voltage multiplier circuitry. DC-transformer modeling of Nx MBC is discussed for the continuous current mode (CCM) and discontinuous current mode (DCM), which helps to analyze the characteristics of the converter in a more practical way and helps to study the effect of semiconductor components, internal resistances, and load on the voltage conversion ratio of the converter. The mode of operation of Nx MBC in the CCM and DCM is also discussed with the boundary condition. The derived analysis is verified by simulations and experimental investigations, and the obtained results of 3x MBC always show good agreement with each other and the theoretical analysis

Improved power quality operation of symmetrical and asymmetrical multilevel inverter using invasive weed optimization technique

Low switching frequency pulse width modulation (PWM) technique for modulation and control of multilevel inverter in medium voltage high power applications is preferred in order to reduce the switching losses. In this context, a multilevel inverter operated with Selective harmonics minimization PWM technique offers better quality waveform at reduced switching losses. After the Fourier series analysis, the system of non-linear simultaneous transcendental equations is obtained. These equations are then solved to obtain switching angles to have certain low order harmonics at minimum value and regulation in the fundamental voltage magnitude. In this paper, a novel invasive weed optimization (IWO) technique is proposed to compute switching angles. The proposed technique can compute switching angles for both symmetrical and asymmetrical multilevel inverters. Thus it has superiority over well-known optimization techniques such as GA, PSO, DE, and ACO, etc. Moreover, in certain modulation index ranges, it provides faster convergence and accurate results which have been demonstrated in the paper. The computational results have been verified with the experimental result on the prototype developed in the laboratory. The field programming gate arrays (FPGA) based controller is used to implement the proposed technique. The hardware results have been found in close agreement with the computed results. 2022This publication was made possible by NPRP grant #[ 13S-0108-20008 ] from the Qatar National Research Fund (A member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. The APC of the paper is funded by the Qatar National Library , Doha, Qatar.Scopu

A New Structure of High Voltage Gain SEPIC Converter for Renewable Energy Applications

The paper proposes a new structure of SEPIC with high voltage gain for renewable energy applications. The proposed circuit is designed by amalgamating the conventional SEPIC with a boosting module. Therefore, the converter benefits from various advantages that the SEPIC converter has, such as continuous input current. Also, high voltage gain and input current continuity make the presented converter suitable for renewable energy sources. The modified SEPIC converter (MSC) provides higher voltage gain compared to the conventional SEPIC and recently addressed converters with a single-controlled switch. The analysis of voltage gain in continuous current mode (CCM) and discontinuous current mode (DCM) is analyzed by considering the non-idealities of the semiconductor devices and passive components. The selection of the semiconductor devices depending on the voltage-current rating is presented along with the designing of reactive components. The numerical simulation and experimental work are carried out, and the obtained results prove the feasibility of the MSC concept and the theoretical analysis.This work was supported by the National Priorities Research Program (NPRP) through the Qatar National Research Fund (a member of the Qatar Foundation) under Grant X-033-2-007.Scopu