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Demercil de Souza Oliveira

Bio: Demercil de Souza Oliveira is an academic researcher from Federal University of Ceará. The author has contributed to research in topics: Topology (electrical circuits) & Three-phase. The author has an hindex of 10, co-authored 40 publications receiving 546 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a new family of dc-dc converters based on the three-state switching cell and voltage multiplier cells is introduced, which can be applied in uninterruptible power supplies, fuel cell systems, and is also adequate to operate as a high-gain boost stage with cascaded inverters in renewable energy systems.
Abstract: This paper introduces a new family of dc-dc converters based on the three-state switching cell and voltage multiplier cells A brief literature review is presented to demonstrate some advantages and inherent limitations of several topologies that are typically used in voltage step-up applications In order to verify the operation principle of this family, the boost converter is chosen and investigated in detail The behavior of the converter is analyzed through an extensive theoretical analysis, while its performance is investigated by experimental results obtained from a 1-kW laboratory prototype and relevant issues are discussed The analyzed converter can be applied in uninterruptible power supplies, fuel cell systems, and is also adequate to operate as a high-gain boost stage with cascaded inverters in renewable energy systems Furthermore, it is suitable in cases where dc voltage step-up is demanded, such as electrical fork-lift, audio amplifiers, and many other applications

116 citations

Journal ArticleDOI
TL;DR: This work introduces a dc-dc boost converter based on the three-state switching cell and voltage multiplier cells that can be applied to uninterruptible power supplies and is also adequate to operate as a high gain boost stage cascaded with inverters in renewable energy systems.
Abstract: This work introduces a dc-dc boost converter based on the three-state switching cell and voltage multiplier cells. A brief literature review is presented to demonstrate some advantages and inherent limitations of several topologies that are typically used in voltage step-up applications. The behavior of the converter is analyzed through an extensive theoretical analysis, while its performance is investigated by experimental results obtained from a 1-kW laboratory prototype, as relevant issues are discussed. The converter can be applied to uninterruptible power supplies and is also adequate to operate as a high gain boost stage cascaded with inverters in renewable energy systems. Furthermore, it can be applied to systems that demand dc voltage step up such as electrical fork-lift, renewable energy conversion systems, and many other applications.

106 citations

Proceedings ArticleDOI
09 Jul 2006
TL;DR: An important feature of this non-isolated boost converter is the lower blocking voltage across the controlled switches compared to similar circuits, which allows the utilization of MOSFETs switches with lower conduction resistances RDS(on).
Abstract: A new non-isolated boost converter with high voltage gain is proposed on this work This converter is suitable for applications with a high voltage gain between the input and the output In this converter, for a given duty cycle, the output to input voltage ratio can be raised by adding transformer turns Another important feature of this converter is the lower blocking voltage across the controlled switches compared to similar circuits, which allows the utilization of MOSFETs switches with lower conduction resistances RDS(on) In order to verify the feasibility of this topology; principle of operation, theoretical analysis, and experimental waveforms are shown for a 1 kW assembled prototype

71 citations

Journal ArticleDOI
TL;DR: This study presents the qualitative and quantitative analyses, design procedure and experimental results on a soft switching cell applied to a high-voltage gain interleaved boost converter with main advantages of a hard switching topology.
Abstract: This study presents the qualitative and quantitative analyses, design procedure and experimental results on a soft switching cell applied to a high-voltage gain interleaved boost converter. An active snubber cell is proposed as a possible solution for the increase of efficiency in a hard switching topology, where switching losses are drastically minimised. The main advantages of the introduced circuit are the common source terminal to all switches; zero-voltage switching of the main switches; zero current switching of the auxiliary switches; low-voltage stress across the switches; balanced voltage across the output capacitors; the presence of a magnetic coupling cell, which allows the gain to be significantly increased; and the magnetic components that are designed for twice the switching frequency. A prototype rated at 500 W is implemented and evaluated, where relevant issues are discussed to validate the theoretical assumptions.

50 citations

Proceedings ArticleDOI
09 Jul 2006
TL;DR: In this article, a voltage doubler rectifier was used as the output stage of an interleaved boost converter with coupled inductors, and the obtained voltage gain was twice that of traditional boost converters due to the doubler stage, although voltage stress across the switches was not increased.
Abstract: This paper proposes the use of a voltage doubler rectifier as the output stage of an interleaved boost converter with coupled inductors. The obtained voltage gain is twice that of traditional boost converters due to the doubler stage, as coupled inductors provide additional voltage gain, although voltage stress across the switches is not increased. The resulting topology is adequate for battery sourced systems which require low current ripple and high voltage gain e.g. UPS's and audio amplifiers. Additionally, it can be used to obtain symmetrical power supply. Theoretical analysis and experimental results from a 1 kW prototype are shown

40 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques, and discuss the advantages and disadvantages of these voltage boosting techniques and associated converters.
Abstract: DC–DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which fundamental energy storing elements (inductors and capacitors) and/or transformers in conjunction with switch(es) and diode(s) are utilized in the circuit. These techniques include switched capacitor (charge pump), voltage multiplier, switched inductor/voltage lift, magnetic coupling, and multistage/-level, and each has its own merits and demerits depending on application, in terms of cost, complexity, power density, reliability, and efficiency. To meet the growing demand for such applications, new power converter topologies that use the above voltage-boosting techniques, as well as some active and passive components, are continuously being proposed. The permutations and combinations of the various voltage-boosting techniques with additional components in a circuit allow for numerous new topologies and configurations, which are often confusing and difficult to follow. Therefore, to present a clear picture on the general law and framework of the development of next-generation step-up dc–dc converters, this paper aims to comprehensively review and classify various step-up dc–dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc–dc converters are presented and summarized with comparative study of different voltage-boosting techniques.

1,230 citations

01 Jan 1992
TL;DR: In this paper, a multilevel commutation cell is introduced for high-voltage power conversion, which can be applied to either choppers or voltage-source inverters and generalized to any number of switches.
Abstract: The authors discuss high-voltage power conversion. Conventional series connection and three-level voltage source inverter techniques are reviewed and compared. A novel versatile multilevel commutation cell is introduced: it is shown that this topology is safer and more simple to control, and delivers purer output waveforms. The authors show how this technique can be applied to either choppers or voltage-source inverters and generalized to any number of switches.<>

1,202 citations

Journal ArticleDOI
TL;DR: A general conceptual circuit for high-step-up, low-cost, and high-efficiency dc/dc conversion is proposed to derive the next-generation topologies for the PV grid-connected power system.
Abstract: The photovoltaic (PV) grid-connected power system in the residential applications is becoming a fast growing segment in the PV market due to the shortage of the fossil fuel energy and the great environmental pollution. A new research trend in the residential generation system is to employ the PV parallel-connected configuration rather than the series-connected configuration to satisfy the safety requirements and to make full use of the PV generated power. How to achieve high-step-up, low-cost, and high-efficiency dc/dc conversion is the major consideration due to the low PV output voltage with the parallel-connected structure. The limitations of the conventional boost converters in these applications are analyzed. Then, most of the topologies with high-step-up, low-cost, and high-efficiency performance are covered and classified into several categories. The advantages and disadvantages of these converters are discussed. Furthermore, a general conceptual circuit for high-step-up, low-cost, and high-efficiency dc/dc conversion is proposed to derive the next-generation topologies for the PV grid-connected power system. Finally, the major challenges of high-step-up, low-cost, and high-efficiency dc/dc converters are summarized. This paper would like to make a clear picture on the general law and framework for the next-generation nonisolated high-step-up dc/dc converters.

1,162 citations

Journal ArticleDOI
TL;DR: This paper proposes transformerless dc-dc converters to achieve high step-up voltage gain without an extremely high duty ratio and develops a prototype circuit to verify the performance.
Abstract: Conventional dc-dc boost converters are unable to provide high step-up voltage gains due to the effect of power switches, rectifier diodes, and the equivalent series resistance of inductors and capacitors. This paper proposes transformerless dc-dc converters to achieve high step-up voltage gain without an extremely high duty ratio. In the proposed converters, two inductors with the same level of inductance are charged in parallel during the switch-on period and are discharged in series during the switch-off period. The structures of the proposed converters are very simple. Only one power stage is used. Moreover, the steady-state analyses of voltage gains and boundary operating conditions are discussed in detail. Finally, a prototype circuit is implemented in the laboratory to verify the performance.

694 citations