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Nandyala Sreeramula Reddy

Bio: Nandyala Sreeramula Reddy is an academic researcher from VIT University. The author has contributed to research in topics: Ćuk converter & Flyback converter. The author has an hindex of 6, co-authored 6 publications receiving 75 citations.

Papers
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Proceedings ArticleDOI
06 Mar 2014
TL;DR: This paper presents a novel non-isolated dual output hybrid DC-DC multilevel converter suitable for photovoltaic applications where two voltages are needed at the same time with opposite polarity.
Abstract: This paper presents a novel non-isolated dual output hybrid DC-DC multilevel converter. The proposed converter topology is suitable for photovoltaic applications where two voltages are needed at the same time with opposite polarity. The proposed DC-DC converter topology is the combination of two high gain multilevel DC-DC converters, one is multilevel boost converter and another is multilevel cuk converter. Two output voltages with opposite polarity are achieved by using only single switch and single input supply. Positive output voltage is obtained from multilevel boost converter and negative output voltage is obtained from multilevel cuk converter. The gain of the converter can be increases by adding appropriate number of capacitors and diodes without disturbing the main circuit. The proposed converter has been designed for photovoltaic applications with rated output parameters 200W, 240V and 200W, −228V. The input voltage is 12V and switching frequency is 50 KHz. The Proposed converter topology is simulated in MATLAB/SIMULINK.

22 citations

Proceedings ArticleDOI
20 Mar 2014
TL;DR: In this paper, the authors proposed a non-isolated high step-up DC-DC converters for photovoltaic applications, where voltage is needs to be step up without using transformer and coupled inductors.
Abstract: This paper proposes a novel non-isolated high step-up DC-DC converters for photovoltaic applications, where voltage is needs to be step-up without using transformer and coupled inductors. In this paper three novel DC-DC converter topologies are discussed in detail, which are suitable for photovoltaic applications. In this proposed converters, two similar inductors are charges in parallel when switches S 1 , S 2 are ON and discharges in series when switches S 1 , S 2 are OFF. The steady state analysis of proposed converters for continuous conduction mode (CCM) and discontinuous conduction mode (DCM) are discussed in detail. The proposed converters have been designed with rated power 200W, input voltage is 24V and switching frequency is 50kHz. The output voltage of the converter-I, H, HI is 168V, 192V, 216V respectively. The simulation results will verify the validity of the analytical design of the proposed DC-DC converters. The proposed converter topologies are simulated in MATLAB/SEVIULINK.

18 citations

Proceedings ArticleDOI
20 Mar 2014
TL;DR: In this article, a novel high gain floating output DC-DC multilevel boost converter is proposed for fuel cell applications, where input supply voltage is needs to be lift with high conversion ratio.
Abstract: This paper presents a novel high gain floating output DC-DC multilevel boost converter. This circuit topology is suitable for fuel cell applications, where input supply voltage is needs to be lift with high conversion ratio. Floating output helps to separate the system from the ground related interference problems. The gain of the floating output DC-DC multilevel converter can be increased by adding capacitors and diodes at the output side. 2N-1 capacitors and 2N-1 diodes are required for designing N-level floating output Dc-Dc multilevel converter. The advantage of multilevel converter is the voltage stress across each device is less, so low voltage devices are applicable for proposed topology. The proposed converter topology is designed for unidirectional power transfer applications. The proposed converter has been designed for five levels with rated power 400W, input voltage is 24V, output voltage is 450V and switching frequency is 50kHz. The simulation results are verified through MATLAB/SIMULINK.

15 citations

Proceedings ArticleDOI
01 Feb 2014
TL;DR: In this paper, a novel high gain buck-boost multilevel converter using double voltage-lift switched-induct or (D-VLSI) cell is proposed.
Abstract: In this paper a novel high gain buck-boost multilevel converter using double voltage-lift switched-induct or (D-VLSI) cell is proposed. Series connection of conventional DC-DC converter is not a viable solution to achieve high voltage gain. Thus, DC-DC multilevel converters are employed to achieve high voltage gain. The proposed high gain multilevel buck-boost converter combines the function of double voltage-lift switched-inductor (D-VLSI) cell and voltage multiplier cell. In this paper double voltage-lift switched-inductor (D-VLSI) cell is used to enhance the boost capability of multilevel buck-boost converter. 2N+1 capacitors, 2N+3 diodes, two switches and two inductors are required to design the proposed N-level buck-boost converter topology. Proposed buck-boost multilevel converter circuit can be designed by using low voltage rating devices, because voltage stress across each power devices is low. The main advantage of proposed converter circuit is high voltage is achieved without using transformer, coupled inductor and extreme duty cycle. The voltage gain of proposed buck-boost multilevel converter is depends upon the duty ratio and number of levels. The proposed high gain multilevel buck-boost converter has been designed for three levels with rated power 200W, output voltage is 300V, input supply voltage is 12V and switching frequency is 50kHz. The proposed buck-boost multilevel converter circuit is simulated in MATLAB/SIMULINE.

10 citations

Proceedings ArticleDOI
20 Mar 2014
TL;DR: Double voltage-lift switched-inductor (D-VLSI) cell is used to enhance the step-up capability of multilevel DC-DC converter to achieve high voltage gain.
Abstract: In this paper a novel high step-up multilevel boost converter using double voltage-lift switched-inductor (D-VLSI) cell is proposed. Series connection of conventional DC-DC boost converter is not a proper solution to achieve high voltage gain. Thus, DC-DC multilevel converters are employed to achieve high voltage gain. The proposed high step-up multilevel boost converter is a combination of double voltage-lift switched-inductor (D-VLSI) cell and voltage multiplier cell. In this paper double voltage-lift switched-inductor (D-VLSI) cell is used to enhance the step-up capability of multilevel DC-DC converter. Two switches, 2N+3 diodes, 2N+1 capacitor and two inductors are required to design the proposed N-level high step-up multilevel boost converter topology. Proposed high step-up multilevel converter circuit can be designed by using low voltage rating devices because blocking voltage across each power devices is low. The main advantage of proposed converter circuit is high voltage is achieved without using transformer, coupled inductor and high duty cycle. The gain of proposed multilevel converter is depends upon the duty ratio and levels present in voltage multiplier cell. Proposed DC-DC converter is designed for unidirectional power transfer applications. The proposed high step-up multilevel converter has been designed for three levels with rated power 300W, output voltage is 324V, input supply voltage is 12V, and switching frequency is 50kHz. The proposed high step-up multilevel converter circuit is simulated in MATLAB/SEVIULINK.

9 citations


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Journal ArticleDOI
TL;DR: The state-of-the-art in unidirectional non-isolated DC-DC Multistage Power Converter (MPC) topologies for FC-VPT application is described and the suitability for different vehicular applications is stated.
Abstract: 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.

99 citations

Journal ArticleDOI
TL;DR: The feasibility of using an ultra-high-voltage-gain dc–dc converter in either the FC or the PV applications is demonstrated, while keeping the high voltage gain and the proposed topology illustrates low switches’ voltage stress resulted in high efficiency.
Abstract: Regarding the inherent structure of some nonpolluting resources such as fuel cell (FC) stacks and photovoltaic (PV) panels, the output exhibits a low voltage, which cannot be employed in the common conventional utilizations. Accordingly, an interference dc–dc converter is extremely required. This paper demonstrates the feasibility of using an ultra-high-voltage-gain dc–dc converter in either the FC or the PV applications. While keeping the high voltage gain, the proposed topology illustrates low switches’ voltage stress resulted in high efficiency. The continuous and discontinuous conduction operation modes, as well as efficiency analysis, are investigated. The prototype setup of 250 W and 400 V output voltage is implemented. The proposed dc–dc converter merits involving ultra-high-voltage ratio, low switches’ voltage stress, and high efficiency are verified via experimental results.

46 citations

Proceedings ArticleDOI
12 Dec 2016
TL;DR: In this article, a new breed of a buck boost converter, named as the XY converter family is proposed, which is 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.
Abstract: 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.

45 citations

Journal ArticleDOI
TL;DR: In this paper, the authors carried out a thorough analysis of these undesirable effects and to propose remedial strategies to minimize them, and they concluded that operating degraded modes lead up to undesirable effects such as electrical overstress on components and input current ripple increasing.

37 citations

Journal ArticleDOI
TL;DR: Three unidirectional step-up ac–dc converter topologies with voltage multiplication on their outputs based on the integration of boost rectifier and the ladder switched-capacitor (SC) cell are presented.
Abstract: This paper presents three unidirectional step-up ac–dc converter topologies with voltage multiplication on their outputs. The first topology is the hybrid boost rectifier and the other two are novel bridgeless structures, all based on the integration of boost rectifier and the ladder switched-capacitor (SC) cell. The new hybrid structures provide high voltage gain with low voltage stress across the switches, high-power factor, and output voltage regulation. This paper presents the principle of operation, steady-state and dynamic analysis, design methodology, and experimental verification. A different approach is also presented for the design methodology of the SC cell and for the analysis of its influence on the dynamic model. Three 1000-W prototypes with a 220-V input voltage, 800-V output voltage, and 100-kHz switching frequency were designed to corroborate the theoretical study. The best efficiency was 97.1 $\%$ in the proposed bridgeless versions and the voltage stress across the switches stands around 400 V. Furthermore, a comparison between the proposed structures and previous topologies is also presented.

26 citations