Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

In this paper, a novel non-isolated DC-DC converter topology is proposed for solar photovoltaic (PV) application. The proposed converter is constructed from an interleaved boost converter (IBC) to reduce the input current ripple. Voltage gain is extended by (i) using voltage lift technique, (ii) replacing the conventional inductors of the IBC by coupled inductors (CIs) with appropriate turns ratio and (iii) connecting a voltage multiplier cell (VMC) across the secondary windings of the CIs. As the voltage gain is extended mainly at the secondary side of the CIs, the switches are subjected to low voltage stress which is only 12.63% of the output voltage. The converter yields a high voltage conversion ratio of 15.83. Experimental results obtained from a 24 V/380 V, 225 W prototype converter operating at 91.6% efficiency serves as a proof of the presented concept which has been employed to achieve high voltage conversion ratio (15.83) with low input current ripple (20%). © 2019 International Solar Energy Society

Electrical

School of Electrical Engineering

Chennai Campus

World University root node

Solar Energy

Interleaved high gain DC-DC converter for integrating solar PV source to DC bus

A novel non-isolated high-step-up high-power DC–DC converter based on coupled inductor (CI) and voltage multiplier cell (VMC) for renewable energy microgrids is presented in this paper. Hybrid combination of three-phase interleaved boost converter with three CIs is chosen to reduce the current ripple at the input and meet the high-power requirement. Three VMCs connected at the secondary side of the CIs serve as gain extension cells. The voltage stress experienced by the switches is only a fraction of the output voltage as the gain extension is mainly achieved at the secondary side of CIs. Practical results obtained from the proposed converter, which operates from a 60 V input and provides an output voltage of 1.1 kV while delivering 3 kW of output power at 92.6% efficiency, validate the proposed concept and design hypothesis. © 2017, Springer-Verlag GmbH Germany, part of Springer Nature.

Electrical Engineering

Modular high-gain DC–DC converter for renewable energy microgrids

In this article, a novel DC–DC converter with high voltage gain capability is presented. The proposed converter is synthesised from (i) a basic two-phase interleaved boost converter (IBC) which uses coupled inductors (CIs) instead of discrete inductors and (ii) diode-capacitor multiplier (DCM) cells to achieve higher voltage conversion ratio. The outputs obtained from the interleaved and the DCM stages are judiciously cascaded with the outputs obtained from the secondary winding of the CIs to enhance the voltage gain. The input current is almost ripple free due to the adopted interleaving mechanism. As voltage gain is extended using CIs and DCMs, the voltage stress on the semiconductor devices is minimal and only a fraction (10.5%) of the output voltage. Experimental results obtained from the 18 V/380 V, 150 W prototype converter, operating at a maximum efficiency of 94% under full-load condition, validate the proposed concept. Further, practical results obtained under closed-loop condition confirm that the converter yields a constant output of 380 V DC which is suitable for microgrid application. © The Institution of Engineering and Technology 2018.

IET Power Electronics

Non-isolated high gain DC–DC converter with low device stress and input current ripple

The use of green energy sources to feed direct current (DC) microgrids is gaining prominence over traditional centralised alternating current (AC) systems. Direct current microgrids are characterised by the use of intermediate DC-DC converter, which acts as power conditioning units. Hence, the choice of an appropriate DC-DC converter becomes significant as the overall system efficiency is strongly dependent on the converter's performance. This paper proposes a novel high-gain–high-power DC-DC converter for DC microgrid, which is one of the significant steps forward in the development of DC microgrids. The suitability of the proposed high-gain–high-power DC-DC converter is demonstrated by experimental tests of the 60 V/1.1 kV, 3 kW converter; test results validate the converter's suitability for DC distribution. A significant number of performance parameters of the proposed converter are compared with state-of-the-art converter topologies demonstrating the superior capabilities of the proposed converter. This paper also portrays the potential benefits that could be reaped by trending towards DC instead of existing alternating current system. The advantages and challenges to be confronted in the foreseeable future while implementing sustainable DC microgrids are also highlighted. Finally, this paper encapsulates renewable energy fed DC microgrid system as an appropriate, technically feasible, economically viable, and competent solution for efficiently utilising the sustainable energy sources. Copyright © 2017 John Wiley & Sons, Ltd.

Fulltext

International Transactions on Electrical Energy Systems

High-gain–high-power (HGHP) DC-DC converter for DC microgrid applications: Design and testing

This study proposes a novel non-isolated high-gain high-power DC-DC converter. The converter is developed from a basic high-gain high-power converter structure. The proposed converter comprises of a three-phase interleaved boost converter, one coupled inductor and a voltage multiplier cell which act as gain extension stage. The main desirable features like voltage gain, stress on the switches and diodes, turns ratio, component utilisation factor and efficiency are summarised. The power circuit, operational details, simulation and experimental results of the 60 V/1.1 kV, 3 kW, 100 kHz proposed converter are presented. © The Institution of Engineering and Technology 2016.

Transformerless high-gain DC–DC converter for microgrids

To meet the ever increasing electrical energy demand, energy conversion from PV sources is gaining prominence. When used in conjunction with existing power system network, the energy extracted from the renewable energy sources can be utilized to electrify remote areas also. The advancements in DC-DC converter topologies and inverter control strategies have led to the wide emergence of grid tied PV systems. The efficiency at which power is fed to the grid hinges largely on the proper choice and performance of the DC-DC converter stage. Hence, there is a compelling need to thoroughly review the performance of existing DC-DC converter topologies. In this paper, a comprehensive review on the evolution and design aspects of High Gain High Power (HGHP) DC-DC converters employable for solar PV fed system is presented. A simple and generalized strategy to derive high gain high power DC-DC converters has been developed and presented. The salient features of five novel converter topologies that have been derived by using the proposed strategy are elaborated to illustrate the validity of the adopted synthesis methodology. The salient features and the feasibility of connecting the derived topologies to the DC grid/micro grid are highlighted. © 2016 Elsevier Ltd

Renewable and Sustainable Energy Reviews

Non isolated high gain DC-DC converter topologies for PV applications – A comprehensive review

In this paper, a non-isolated high step-up high power DC-DC converter based on coupled inductor and voltage multiplier cell (VMC) is proposed for renewable energy applications. To obtain high voltage gain and high output power, three interleaved coupled inductors and three VMCs are used. Each VMC consists of secondary winding of the coupled inductor, two diodes and two capacitors which charge and discharge alternately through the diodes. The three stages present in interleaved boost converter reduce the current stress on the switch and input current ripple. Voltage stress on the power switches is reduced by using coupled inductors with proper turns ratio. The proposed converter produces a voltage gain of 23 and delivers 3kW power output. The converter has a modular structure which facilitates smooth increment in voltage gain and output power requirement. The operating principle, characteristic waveforms, design details and simulation results of the proposed converter prove the desirable features. © 2014 IEEE.

2014 IEEE 2nd International Conference on Electrical Energy Systems (ICEES)

High gain high power non-isolated DC-DC converter for renewable energy applications

This paper presents a single switch topology of DC-DC multilevel buck-boost converter with very high voltage gain ratio. It is a pulse width modulation (PWM) based multilevel buck-boost converter (MLBBC) consisting of 2N-1 Diodes, 2N-1 capacitors for N level boost converter. The proposed converter topology is a combination of buck-boost converter and cockcroft-walton voltage multiplier. The main advantage of proposed topology is output voltage can be increased by increasing number of capacitors and diodes at output side without disturbing the main circuit. The mathematical analysis and circuit operation discussed. © 2014 IEEE.

VIT Unitversity

2014 International Conference on Advances in Electrical Engineering (ICAEE)

A high gain DC-DC converter using voltage multiplier

A hybrid non isolated high step up high power converter with asymmetric interleaved boost converter and voltage multiplier cell with one multi-coupled inductor is proposed in this paper. Appropriate coupling of primary and secondary windings of the coupled inductor enhances the voltage gain and power delivering capability. Turns ratio of the coupled inductors is kept very small so that the leakage energy does not induce high voltage stress which results in incremental switching losses. To reduce the current stress on the switches, current through the device is shared by applying interleaving technique to the first stage of the proposed converter. The proposed converter is capable of producing a gain of 36 at a power level of 3kW. Design details of a 60V/2.2kV, 3kW DC-DC converter that operates at 100 kHz are presented. Simulation results validate the design details and prove the superior features of the proposed converter. © 2014 IEEE.

Non isolated high gain high power DC-DC converter

This paper introduces a novel high gain DC-DC converter topology which can be used for photovoltaic (PV) applications. The proposed DC-DC converter consists of 3 interleaved boost converters and 2 voltage multiplier cells (VMC). The operating principle, characteristic waveforms, design details along with the simulation results prove the validity of the design and its superiority over existing converter topologies in terms of its ability to provide high voltage gain at higher power level and low device stress. The proposed topology is able to produce a voltage gain of 10 and deliver 3kW output power at 88% efficiency. © 2013 IEEE.

2013 Annual International Conference on Emerging Research Areas and 2013 International Conference on Microelectronics, Communications and Renewable Energy