Modified multilevel buck-boost converter with equal voltage across each capacitor: Analysis and experimental investigations

Recently, the circuitry of Multilevel Buck-Boost Converter (here, called MBBC1) is suggested in the literature to attain high inverting voltage by increasing the output levels of the classical buck-boost converter. However, the only circuitry is suggested and detail investigations are not provided. The major drawbacks of MBBC1 are the voltages across the load capacitors side are unequal and the input current is not continuous. Therefore, the MBBC1 is not well suited to feed multilevel inverter where a stack of capacitors is required with equal voltage across each capacitor. A new modified MBBC called MBBC2 is proposed to achieve continuous input current and equal voltage across each capacitor. The circuitry of MBBC1 and MBBC2 configurations are analysed with non-idealities to investigate its effects on the voltage conversion ratio. The Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) boundary conditions and modes of operation for MBBC1 and MBBC2 configurations are presented. The procedure for basics design and components selection is elaborated. Additionally, comparison of MBBC1, MBBC2 and recently proposed a non-isolated DC-DC configuration is provided. The performances of MBBC1 and MBBC2 configurations are tested with simulation and experimental work, and obtained results consistently show a good agreement with the theoretical approach. - The Institution of Engineering and Technology 2019.This publication was made possible by NPRP grant no. [X-033-2-007] from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

High gain three-state switching hybrid boost converter for DC microgrid applications

A novel high gain three-state switching hybrid boost (TSS-HB) converter for DC microgrid applications is proposed in this study. The TSS-HB converter is developed from a conventional boost converter with voltage lift technique. The high voltage gain is achieved by the inclusion of an additional semiconductor switch. Further, this structure reduces the voltage and current stress of the switches and diodes. The proposed TSS-HB converter operates in three switching states with the help of two different duty ratios (k1 and k2). The power circuitry, continuous conduction mode (CCM) and discontinues conduction mode (DCM), and characteristics waveform are discussed in detail based on the theoretical background. The voltage gain and efficiency analysis of TSS-HB in CCM is presented with consideration of non-ideal circuit components. While boundary condition and voltage gain in DCM is discussed with ideal components. The comparison sections highlight the advantages of TSS-HB over existed topologies with the same number of components. Further, the selection of semiconductor devices and the design of components are discussed in detail. Finally, the hardware results are presented which validate the predicted characteristics of TSS-HB converter. - The Institution of Engineering and Technology 2019.This publication was made possible by NPRP grant # [X-033-2-007] from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

New tri-switching state non-isolated high gain DC-DC boost converter for microgrid application

High efficiency is an important requirement from DC-DC converter in DC microgrid system when integrated with renewable energy sources. This study proposes a new tri-switching state non-isolated high gain boost converter for 400 V DC microgrid applications. The proposed converter developed by modifying the conventional boost converter with advantageous features such as; high-voltage gain operation with two different duty pulses to overcome the restriction of high duty ratio and continuous input current. Moreover, semiconductor components in the proposed converter are subjected to reduced voltage stress for a shorter duration when compared to conventional existing topologies. Steady state (with and without non-idealities consideration) and performance analysis are presented to validate the viability of the proposed converter for high gain operation in grid-connected systems. For experimental validation, a prototype model of the proposed converter is developed for 31 V/400 V, 500 W and operated at 50 kHz switching frequency. The converter is tested for a power range of 100-500 W for two different duty range (case: 1-k1 kept fixed and k2 is varied, case: 2-k2 kept fixed and k1 is varied) to validate the consistency in output voltage. Hardware results obtained validates superior performance and higher efficiency compared to conventional existing topologies. - The Institution of Engineering and Technology 2019.This publication was made possible by NPRP grant no. X-033-2-007 from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

Proximal methods for the elastography inverse problem of tumor identification using an equation error approach

In this chapter, we study a nonlinear inverse problem in linear elasticity relating to tumor identification by an equation error formulation. This approach leads to a variational inequality as a necessary and sufficient optimality condition. We give complete convergence analysis for the proposed equation error method. Since the considered problem is highly ill-posed, we develop a stable computational framework by employing a variety of proximal point methods and compare their performance with the more commonly used Tikhonov regularization