The automobile companies are focusing on recent technologies such as growing Hydrogen (H2) and Fuel Cell (FC) Vehicular Power Train (VPT) to improve the Tank-To-Wheel (TTW) efficiency. Benefits, the lower cost, ‘Eco’ friendly, zero-emission and high-power capacity, etc. In the power train of fuel cell vehicles, the DC-DC power converters play a vital role to boost the fuel cell stack voltage. Hence, satisfy the demand of the motor and transmission in the vehicles. Several DC-DC converter topologies have proposed for various vehicular applications like fuel cell, battery, and renewable energy fed hybrid vehicles etc. Most cases, the DC-DC power converters are viable and cost-effective solutions for FC-VPT with reduced size and increased efficiency. This article describes the state-of-the-art in unidirectional non-isolated DC-DC Multistage Power Converter (MPC) topologies for FC-VPT application. The paper presented the comprehensive review, comparison of different topologies and stated the suitability for different vehicular applications. This article also discusses the DC-DC MPC applications more specific to the power train of a small vehicle to large vehicles (bus, trucks etc.). Further, the advantages and disadvantages pointed out with the prominent features for converters. Finally, the classification of the DC-DC converters, its challenges, and applications for FC technology is presented in the review article as state-of-the-art in research.

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Survey of DC-DC Non-Isolated Topologies for Unidirectional Power Flow in Fuel Cell Vehicles

This article presents a self-balanced multistage DC-DC step-up converter for photovoltaic applications. The proposed converter topology is designed for unidirectional power transfer and provides a doable solution for photovoltaic applications where voltage is required to be stepped up without magnetic components (transformer-less and inductor-less). The output voltage obtained from renewable sources will be low and must be stepped up by using a DC-DC converter for photovoltaic applications. 2 K diodes and 2 K capacitors along with two semiconductor control switch are used in the K-stage proposed converter to obtain an output voltage which is (K + 1) times the input voltage. The conspicuous features of proposed topology are: (i) magnetic component free (transformer-less and inductor-less); (ii) continuous input current; (iii) low voltage rating semiconductor devices and capacitors; (iv) modularity; (v) easy to add a higher number of levels to increase voltage gain; (vi) only two control switches with alternating operation and simple control. The proposed converter is compared with recently described existing transformer-less and inductor-less power converters in term of voltage gain, number of devices and cost. The application of the proposed circuit is discussed in detail. The proposed converter has been designed with a rated power of 60 W, input voltage is 24 V, output voltage is 100 V and switching frequency is 100 kHz. The performance of the converter is verified through experimental and simulation results.

A Multistage DC-DC Step-Up Self-Balanced and Magnetic Component-Free Converter for Photovoltaic Applications: Hardware Implementation

In this paper, closed-loop control and boundary condition for continuous conduction mode and discontinuous conduction mode of nonisolated inverting N × multilevel boost converter (MBC) are articulated. Inverting N × MBC combines the features of classical boost converter and voltage multiplier to attain inverting N times higher voltage. Consequently, the inverting N × MBC provides a viable solution for high-voltage step-up photovoltaic applications with low voltage rating reactive components and semiconductor devices. The control strategy with saturation limiter is employed to achieve highly stable voltage. The modes of operation, benefits of inverting N × MBC, and key factors for the selection of semiconductor devices and sizing of the reactive components are discussed. Additionally, the effects of reactive components and semiconductor devices on the output voltage are examined. Experimental results of the developed circuit are presented to validate the design of converter, and effectiveness and robustness of the implemented control algorithm for different input and output side perturbations.

Closed-Loop Control and Boundary for CCM and DCM of Nonisolated Inverting N × Multilevel Boost Converter for High-Voltage Step-Up Applications

In significant cases, the generated voltage needs to be step-up with high conversion ratio by using the DC-DC converter as per the requirement of the load. The drawbacks of traditional boost converter are it required high rating semiconductor devices and have high input current ripple, low efficiency, and reverse recovery voltage of the diodes. Recently, the family of Multilevel Boost Converter suggested and suitable configuration to overcome the above drawbacks. In this article, hybrid DC-DC non-isolated and non-inverting Nx Interleaved Multilevel Boost Converter (Nx-IMBC) is analyzed in Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) with boundary condition and investigated in detail. The Nx-IMBC circuit combined the features of traditional Interleaved Boost Converter (IBC) and Nx Multilevel Boost Converter (Nx-MBC). The modes of operation, design of Nx-IMBC and the effect of the internal resistance of components are presented. The comparison study with various recent DC-DC converters is presented. The experimental and simulation results are presented with or without perturbation in input voltage, output power and output reference voltage which validates the design, feasibility, and working of the converter.

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Analysis and Investigation of Hybrid DC–DC Non-Isolated and Non-Inverting Nx Interleaved Multilevel Boost Converter (Nx-IMBC) for High Voltage Step-Up Applications: Hardware Implementation

In this treatise, 4Nx hybrid Non Inverting & Non Isolated (NI-NI) DC-DC interleaved multi-level boost converter (4Nx IMBC) for renewable energy applications is proposed. The proposed 4Nx IMBC is derived by coalescing the feature of 2Nx DC-DC Interleaved Multi-level Boost Converter (2Nx IMBC), voltage-lift-switched-inductor-modified (VLSIm Cell) and Cockcroft Walton (CW) voltage multipliers. The 4Nx converter provides 4N times more conversion voltage ratio compared to conventional boost converter where N denotes the number of output stages of the 4Nx IMBC. To make renewable energy sources applicable at user end its DC voltage magnitude needs to be incremented with high conversion. Existing and recently proposed DC-DC converter are not sufficiently expert to employ practically, because of stability issues, high duty cycle and high ripple in the output. To overcome the conversion ratio problem isolated boost DC-DC converter are in use but it makes circuitry bulky and costly because of transformer and several coupled inductors. The converter topology proposed in this treatise reduces the output ripple and overcome the problem mentioned above without exploiting extreme values of duty cycle or transformers. Simulations results of proposed circuitry are presented which verify the analysis, function, working modes & feasibility of proposed circuitry converter.

4Nx Non-Isolated and Non-Inverting hybrid Interleaved Multilevel Boost Converter based on VLSIm Cell and Cockcroft Walton voltage multiplier for renewable energy applications

A New breed of a buck boost converter, named as the XY converter family is proposed in this article. In the XY family, 16 topologies are presented which are highly suitable for renewable energy applications which require a high ratio of DC-DC converter; such as a photovoltaic multilevel inverter system, high voltage automotive applications and industrial drives. Compared to the traditional boost converter and existing recent converters, the proposed XY converter family has the ability to provide a higher output voltage by using less number of power devices and reactive components. Other distinct features of the XY converter family are i) Single control switch ii) Provide negative output voltage iii) Non-isolated topologies iv) High conversion ratio without making the use of high duty cycle and v) modular structure. XY family is compared with the recent high step-up converters and the detailed description of XY converter family and its topologies are presented. The simulation results are provided and it confirms the feasibility, functionality and validity of the concepts of the proposed XY converter family.

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X-Y converter family: A new breed of buck boost converter for high step-up renewable energy applications

This article presents an inverting Nx multilevel boost converter (Inverting Nx MBC) with continuous input current for DC link applications where several negative voltage levels are required with self-balancing such as photovoltaic (PV) multilevel inverter systems. The voltage obtains from the photovoltaic array need to boost before a feed to inverter for practical utilization or grid connect. In this paper new inverting Nx multilevel Boost converter (Inverting Nx MBC) with mode of operation and conversion ratio is discussed in detail. The proposed converter provides negative N time output voltage of the traditional boost converter. The main feature of this topology provides negative high-conversion ratio without using a transformer, continuous input current, moderate duty cycle operation and modularity. The proposed converter topologies are a combination of traditional boost converters and Cockcroft Walton (CW) multiplier. In this topology, each device block only one voltage level. Hence, low voltage devices may be used. The simulation results are provided which validates the functionality of proposed converter topology.

Non-isolated and inverting Nx multilevel boost converter for photovoltaic DC link applications

In this article, performance of gene expression data is analyzed using statistical method resembling Mann–Whitney U test. Biological field investigation of gene expression data is one of the budding domains, in which lot of research work is projected. The finding of the most correlated genes into a group is one of the challenging tasks that will be measured using some of the statistical methods like parametric or nonparametric methods. The microarray is taken as input from the gene expression data that is applied into different methods such as two-sample tests, one-way ANOVA, paired t-test, and Mann–Whitney U test. Scientifically evaluating the recital of each scheme based on virtual and natural information beneath conditions the result shows that clearly the Mann–Whitney U test will produce better result of correlated result and form as cluster group.

Performance Analysis of Gene Expression Data Using Mann–Whitney U Test

In this article, the performance enhancement of statistically significant bicluster using analysis of variance is articulated. Various statistical methods are used to analyze the gene expression level. It is found that analysis of variance is one of the efficient methods for aggregation between a pair of genes. It computes the values by comparing the mean value of each group, and results are tested using the hypothesis to calculate the p-value. Various tests are conducted to increase the performance of the gene pair. Various clustering techniques are functional to investigate the gene expression information for both homogeneous and heterogeneous. Statistical approaches are used to identify the relevant information from the subset of genes. Various testing methods were conducted to enhance the performance of correlated genes. When compared with the biclustering methods such as the paired t-test, two-sample tests, the ANOVAs One sample test produces better result.

The Performance Enhancement of Statistically Significant Bicluster Using Analysis of Variance

In this chapter, DC–DC current buck–boost converter using duality concept is articulated with the help of DC transformer modelling. Buck–boost converter plays a dominant part of switch mode power supply (SMPS) and drives applications for voltage and current control. Advantage of employing buck–boost converter is that it provides voltage less as well as greater than input voltage. The suggested converter is dual of traditional buck–boost converter and provides a flexible control of current for SMPS and drives applications. The duality concept is applied on conventional voltage source buck–boost converter to obtain proposed converter (current buck–boost converter). The formation of proposed circuit is discussed in detail along with its mathematical analysis and equations. MATLAB is used to simulate proposed and results prove practicability and operation of proposed circuit of converter.

S. B. Mahajan

Papers

X-Y converter family: A new breed of buck boost converter for high step-up renewable energy applications

Non-isolated and inverting Nx multilevel boost converter for photovoltaic DC link applications

Performance Analysis of Gene Expression Data Using Mann–Whitney U Test

The Performance Enhancement of Statistically Significant Bicluster Using Analysis of Variance

Buck–Boost Current Converter Using Duality Concept and Its DC Transformer Modelling