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44 results on '"Cuk"'

1. Design, Simulation and Analysis of DC–DC Cuk LED Drivers

Author

Lakshmi Praba, B., Vidhu Priya, V., Seyezhai, R., Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Tan, Kay Chen, Series Editor, Murari, Krishna, editor, Singh, Bhim, editor, and Sood, Vijay Kumar, editor

Published
2024
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2. The design of a hybrid DC/DC converter for LED lighting system using a single switch

Author

Emad Alhani and Fatih Anayi

Subjects
LED driver, DC/DC converter, Topology, Luo, Cuk, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

A novel hybrid Luo-Cuk converter designed for LED lighting systems combines elements from both Luo and Cuk topologies. By integrating the input branch of both topologies, the converter, employing a single switch, can generate two distinct types of outputs simultaneously. One output follows a Luo-type, while the other adopts a Cuk-type . Through a series connection of the outputs from Luo and Cuk topologies, the voltage gain of the converter has been notably enhanced. The converter's output can be effectively regulated using a single controller. To validate the consistency between the topology's performance and theoretical analysis, simulation and prototype results have been provided.

Published
2023
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3. Solar photo voltaic based hybrid CUK, SEPIC, ZETA converters for microgrid applications

Author

Ingilala Jagadeesh and Vairavasundaram Indragandhi

Subjects
Microgrid, Solar PV, Fuel cell, CUK, SEPIC, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

The emergence of converters has triggered a paradigm transfer in the field of power electronics. Recently, DC/DC converters have predominantly employed alternative energy sources and become viable technologies for low- and high-power applications. The DC/DC converter is crucial in power conversion within renewable energy systems, such as hydro, solar photovoltaic (PV), fuel cells (FC), and wind. Its primary role is to modify the voltage and current levels to meet the system's requirements. This article comprehensively examines CUK, ZETA, and single-ended primary-inductor converter (SEPIC) in several phases, including enhancing efficiency, achieving cost-effective operation and mitigating switching losses. Furthermore, this study overviews each converter's operational modes and efficiency-output power comparison. This article compares integrating solar PV and FC technologies into various converters.

Published
2023
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4. A Pareto Based Comparison of DC/DC Converters for Variable DC-Link Voltage in Electric Vehicles

Author

Timijan Velic, Yannik Becher, and Nejila Parspour

Subjects
Automotive, buck, ĆUK, dc/dc converter, DC-Link voltage, electric drive, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

High battery voltages increase inverter switching and harmonic losses of the electric machine. These losses dominate at low speeds in the partial load range, where the customer relevant Worldwide Harmonized Light Vehicles Test Procedure (WLTC) driving cycle is located. By installing a bidirectional DC/DC converter between the inverter and the battery, the input voltage of the inverter can be adjusted to various torque/speed conditions, thereby enhancing the efficiency and range of the electric sports car. Outside of the WLTC, the DC/DC converter is not operated and is short-circuited by a bypass. Additionally, the utilization of synchronous modulation methods, as opposed to space vector pulse width modulation (SVPWM), within the WLTC is made possible by the variable DC-Link voltage, further reducing switching and harmonic losses. In this paper, different topologies of DC/DC converters are proposed. The investigations are conducted on an 800 V system. To facilitate this, a script-based toolchain was developed based on analytic and fast calculating waveform models. The impact of the DC-Link voltage on energy efficiency during the WLTC is examined, and sensitivities are presented. A multi-objective optimization is carried out based on the WLTC driving cycle to demonstrate the maximum trade-offs between increasing the electric range and the power density of the DC/DC converter.

Published
2023
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5. A novel DC-DC converter for photovoltaic applications

Author

Nathan, Kumaran Saenthan and Long, Teng

Subjects
621.31, Renewable energy, Solar power, Solar photovoltaics, DC-DC converter, DC-DC power conversion, DC-AC power conversion, MPPT, Bipolar DC output, Solar power generation, Grounding, Power electronics, CCS converter, CI-CCS converter, Coupled inductors, Cuk, SEPIC, Integrated magnetics
Abstract

Growing concerns about climate change have led to the world experiencing an unprecedented push towards renewable energy. Economic drivers and government policies mean that small, distributed forms of generation, like solar photovoltaics, will play a large role in our transition to a clean energy future. In this thesis, a novel DC-DC converter known as the Coupled Inductors Combined Cuk-SEPIC' (CI-CCS) converter is explored, which is particularly attractive for these photovoltaic applications. A topological modification is investigated which provides several benefits, including increased power density, efficiency, and operational advantages for solar energy conversion. The converter, which is based on the combination of the Cuk and SEPIC converters, provides a bipolar output (i.e. both positive and negative voltages). This converter also offers both step-up and step-down capabilities with a continuous input current, and uses only a single, ground-referenced switching device. A significant enhancement to this converter is proposed: magnetic coupling of the converter's three inductors. This can substantially reduce the CI-CCS converter's input current ripple - an important benefit for maximum power point tracking (MPPT) in photovoltaic applications. The effect of this coupling is examined theoretically, and optimisations are performed - both analytically and in simulations - to inform the design of a 4 kW prototype CI-CCS converter, switched at a high frequency (100 kHz) with a silicon carbide (SiC) MOSFET. Simulation and experimental results are then presented to demonstrate the CI-CCS converter's operation and highlight the benefits of coupling its inductors. An efficiency analysis is also undertaken and its sources of losses are quantified. The converter is subsequently integrated into a domestic photovoltaic system to provide a practical demonstration of its suitability for such applications. MPPT is integrated into the CI-CCS DC-DC converter, and a combined half bridge/T-type converter is developed and paired with the CI-CCS converter to form an entirely transformerless single-phase solar energy conversion system. The combination of the CI-CCS converter's bipolar DC output with the combined half bridge/T-type converter's bipolar DC input allows grounding at both the photovoltaic panels and the AC grid's neutral point. This eliminates high frequency common mode voltages from the PV array, which in turn prevents leakage currents. The entire system can be operated in grid-connected mode - where the objective is to maximise power extracted from the photovoltaic system, and is demonstrated in stand-alone mode - where the objective is to match solar generation with the load's power demands.

Published
2019
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6. Simulation of SIMO based DC-DC Converter for Multi Level Solar PV Inverter

Author

Agrawal Ajay, Chaudhary Pavan, Kumar Ravindra, and Kulhar Kuldeep Singh

Subjects
dc supplies, cuk, h-bridge, pv inverter, Environmental sciences, GE1-350
Abstract

Simulation of SIMO based DC-DC Converter for multi level Solar PV Inverter is presented in this paper. In order to reduce the number of distinct DC supplies for an H-bridge inverter SIMO DCDC converter is applied which in turn allows the usage of single PV system for a multi level H-bridge inverter. Simulation model of three level and five level inverters is built and results are presented to validate the proposed ideas.

Published
2024
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7. Performance Comparison of Dual Stage Photovoltaics-Based Water Pumping Systems

Author

Tomar, Anuradha, Mittal, Ayush, Pattnaik, Amruta, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zhang, Junjie James, Series Editor, Iqbal, Atif, editor, Malik, Hasmat, editor, Riyaz, Ahmed, editor, Abdellah, Kouzou, editor, and Bayhan, Sertac, editor

Published
2021
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8. Comparison of Average Current Controlled PFC SEPIC and CUK Converter Feeding Current Controlled SRM

Author

Erdal Şehirli and Yücel Çetinceviz

Subjects
CUK, PFC, SEPIC, SRM, THD, Engineering (General). Civil engineering (General), TA1-2040
Abstract

In this paper, current control of 6/4 switched reluctance motor (SRM) fed by both power factor correction (PFC) SEPIC and CUK converter is realised and asymmetric bridge converter is used to drive SRM. Furthermore, SEPIC and CUK DC-DC converters are connected in series to diode bridge rectifier in order to build PFC converters. Average current control of PFC converters is carried out by PI algorithm and both converters are operated at continuous conduction mode (CCM). Besides, switching frequency of PFC and asymmetric bridge converters is 62, 9 kHz with 5750 W power. Studies are conducted by using MATLAB/Simulink software. Total harmonic distortions (THD)s of grid current, grid power factor (PF) and output voltages of the converters are compared. Also, THDs of grid current of each converter are compared by IEEE 519-2014 standard. In addition, current waveform and flux of SRM phases are shown. It is validated by simulations that PFC CUK converter gives better result with 9.08% THD, 0.998 PF than PFC SEPIC converter having 9.61% THD and 0.997 PF. Furthermore, both converters provide the limit defined by standards.

Published
2022
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9. Comparative Study of Buck-Boost, SEPIC, Cuk and Zeta DC-DC Converters Using Different MPPT Methods for Photovoltaic Applications.

Author

Seguel, Julio López, Seleme Jr., Seleme I., and Morais, Lenin M. F.

Subjects
*DC-to-DC converters, *PHOTOVOLTAIC power systems, *FUZZY logic, *COMPARATIVE studies
Abstract

The power produced in a photovoltaic (PV) system is highly dependent on meteorological conditions and the features of the connected load. Therefore, maximum power point tracking (MPPT) methods are crucial to optimize the power delivered. An MPPT method needs a DC-DC converter for its implementation. The proper selection of both the MPPT technique and the power converter for a given scenario is one of the main challenges since they directly influence the overall efficiency of the PV system. This paper presents an exhaustive study of the performance of four step-down/step-up DC-DC converter topologies: Buck-Boost, SEPIC, Zeta and Cuk, using three of the most commonly implemented MPPT techniques: incremental conductance (IncCond), perturb and observe (P&O) and fuzzy logic controller (FLC). Unlike other works available in the literature, this study compares and discusses the performance of each MPPT/converter combination in terms of settling time and tracking efficiency of MPPT algorithms, and the conversion efficiency of power converters. Furthermore, this work jointly considers the effects of incident radiation variations, the temperature of the PV panel and the connected load. The main contribution of this work, other than selecting the best combination of converter and MPPT strategy applied to typical PV systems with DC-DC power converters, is to formulate a methodology of analysis to support the design of efficient PV systems. The results obtained from simulations performed in Simulink/MATLAB show that the FLC/Cuk set consistently achieved the highest levels of efficiency, and the FLC/Zeta combination presents the best transient behavior. The findings can be used as a valuable reference for the decision to implement a particular MPPT/converter configuration among those included in this study. [ABSTRACT FROM AUTHOR]

Published
2022
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10. The Buck/Boost Shunt Converter for the PV Systems

Author

Mohammed, Seddik, Zouggar, Smail, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zhang, Junjie James, Series Editor, Hajji, Bekkay, editor, Tina, Giuseppe Marco, editor, Ghoumid, Kamal, editor, Rabhi, Abdelhamid, editor, and Mellit, Adel, editor

Published
2019
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11. Fuzzy Logic Controller-Based Bridgeless Cuk Converter for Power Factor Correction

Author

Meena Devi, R., Kavitha, M., Geetha, V., Preethi Pauline Mary, M., Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Bhaskar, M. Arun, editor, Dash, Subhransu Sekhar, editor, Das, Swagatam, editor, and Panigrahi, Bijaya Ketan, editor

Published
2019
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12. Comparative Study of Buck-Boost, SEPIC, Cuk and Zeta DC-DC Converters Using Different MPPT Methods for Photovoltaic Applications

Author

Julio López Seguel, Seleme I. Seleme, and Lenin M. F. Morais

Subjects
Buck-Boost, SEPIC, Cuk, Zeta, MPPT methods, PV system, Technology
Abstract

The power produced in a photovoltaic (PV) system is highly dependent on meteorological conditions and the features of the connected load. Therefore, maximum power point tracking (MPPT) methods are crucial to optimize the power delivered. An MPPT method needs a DC-DC converter for its implementation. The proper selection of both the MPPT technique and the power converter for a given scenario is one of the main challenges since they directly influence the overall efficiency of the PV system. This paper presents an exhaustive study of the performance of four step-down/step-up DC-DC converter topologies: Buck-Boost, SEPIC, Zeta and Cuk, using three of the most commonly implemented MPPT techniques: incremental conductance (IncCond), perturb and observe (P&O) and fuzzy logic controller (FLC). Unlike other works available in the literature, this study compares and discusses the performance of each MPPT/converter combination in terms of settling time and tracking efficiency of MPPT algorithms, and the conversion efficiency of power converters. Furthermore, this work jointly considers the effects of incident radiation variations, the temperature of the PV panel and the connected load. The main contribution of this work, other than selecting the best combination of converter and MPPT strategy applied to typical PV systems with DC-DC power converters, is to formulate a methodology of analysis to support the design of efficient PV systems. The results obtained from simulations performed in Simulink/MATLAB show that the FLC/Cuk set consistently achieved the highest levels of efficiency, and the FLC/Zeta combination presents the best transient behavior. The findings can be used as a valuable reference for the decision to implement a particular MPPT/converter configuration among those included in this study.

Published
2022
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13. Design, Analysis and Comparison of Si- and GaN-Based DC-DC Wide-Input-Voltage-Range Buck-Boost Converters.

Author

Koszel, Mikołaj, Grzejszczak, Piotr, Nowatkiewicz, Bartosz, and Wolski, Kornel

Subjects
*VOLTAGE, *TRANSISTORS, *CAPACITORS, *ELECTRIC vehicles, *ENERGY storage
Abstract

The purpose of the article is a comparison between DC/DC topologies with a wide input voltage range. The research also explains how the implementation of GaN E-HEMT transistors influences the overall efficiency of the converter. The article presents a process of selection of the most efficient topology for stabilization of the battery storage voltage (9 V - 36 V) at the level of 24 V, which enables the usage of ultracapacitor energy storage in a wide range of applications, e.g., in automated electric vehicles. In order to choose the most suitable topology, simulation and laboratory research were conducted. The two most promising topologies were selected for verification in the experimental model. Each of the converters was constructed in two versions: with Si and with GaN E-HEMT transistors. The paper presents experimental research results that consist of precise power loss measurements and thermal analysis. The performance with an increased switching frequency of converters was also examined. [ABSTRACT FROM AUTHOR]

Published
2021
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14. DEVELOPMENT OF ROBUST CONTROL USING H8 TECHNIQUE FOR DC/DC CONVERTERS.

Author

Diwakar, Kunal and Bansal, Lalit

Subjects
ROBUST control, SLIDING mode control
Abstract

The emphasis of this paper is to develop robust control using H∞ control method for DC/DC converters namely buck, boost, buck-boost and cuk. Since DC/DC converters are nonlinear in nature classical control approaches fails to provide the robust behavior. In this paper a generalized and feasible H∞ algorithm is designed and implied to DC/DC converters. The developed H∞ controller is compared with sliding mode controller and PI based controller. The controller performance and stability were tested through extensive simulation of models on MATLAB. [ABSTRACT FROM AUTHOR]

Published
2021
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15. Derivation of High Voltage-Gain Step-Up DC-DC Power Converters.

Author

Dahono, Pekik Argo

Subjects
*ELECTRIC network topology, *ELECTRIC potential, *VALIDITY of statistics, *ELECTRON tube grids
Abstract

This paper presents a new method to derive high voltage-gain step-up dc-dc power converters is presented in this paper. Four step-up dc-dc power converters are derived by a unique parallel-series combination of basic dc-dc power converters. The obtained high voltage-gain power converters have better efficiency than the ones that can be obtained obtained by using a conventional dc-dc boost power converter. Interleaving the combined converters can be used to further reduce the input current and output voltage ripples. Simulation and measurement results are included to show the validity of the proposed concept of high voltage-gain step-up dc-dc power converters [ABSTRACT FROM AUTHOR]

Published
2019
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16. Acerca de las bifurcaciones de un convertidor ZAD-Ćuk.

Author

Grisales Aguirre, Andrés Mauricio, Amador Rodríguez, Andrés Felipe, and Casanova Trujillo, Simeón

Abstract

In this paper, we make a bifurcation analysis of a mathematical model for a Ćuk converter when it is controlled by center PWM (Pulse Width Modulator) and ZAD (Zero Average Dynamics) strategy. Different nonlinear phenomena like bifurcations and chaos are reported when the parameters associated to the commutation surface are varied. Finally, the existence of chaotic behavior in the system is determined using Lyapunov exponents. [ABSTRACT FROM AUTHOR]

Published
2017

17. Design optimization of a Ćuk DC/DC converter based on reliability constraints.

Author

ZARRIN AREHKOUSHAN, Amirreza, ABAPOUR, Mehdi, and FARAKHOR, Amir

Subjects
*POWER electronics, *ELECTRIC current converters, *RELIABILITY in engineering, *ELECTROMAGNETIC interference, *SIGNAL integrity (Electronics)
Abstract

Recently, power electronic converters have widely been used in various applications. This has led to concerns about the reliability of power converters and, as a result, their optimal design has attracted a lot of attention. However, the reliability-based optimal design of the Ćuk DC-DC converter has not yet been studied. A new methodology is presented here for the optimal design of the Ćuk converter based on reliability constraints. In this study, the converter is designed to minimize power losses in order to maximize the mean time to failure of the converter. A genetic algorithm is used as the optimization technique, resulting in the optimal duty cycle and switching frequency of the converter. Other parameters of the converter are selected to satisfy the desired electrical constraints. Finally, three scenarios along with simulation results are presented to verify the feasibility of the proposed design methodology. In addition, an experimental prototype is implemented to validate the proper operation of the converter. [ABSTRACT FROM AUTHOR]

Published
2017
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18. Comparison of Average Current Controlled PFC SEPIC and CUK Converter Feeding Current Controlled SRM

Author

Şehirli, Erdal and Çetinceviz, Yücel

Subjects
CUK, PFC, SEPIC, SRM, THD
Abstract

In this paper, current control of 6/4 switched reluctance motor (SRM) fed by both power factor correction (PFC) SEPIC and CUK converter is realised and asymmetric bridge converter is used to drive SRM. Furthermore, SEPIC and CUK DC-DC converters are connected in series to diode bridge rectifier in order to build PFC converters. Average current control of PFC converters is carried out by PI algorithm and both converters are operated at continuous conduction mode (CCM). Besides, switching frequency of PFC and asymmetric bridge converters is 62, 9 kHz with 5750 W power. Studies are conducted by using MATLAB/Simulink software. Total harmonic distortions (THD)s of grid current, grid power factor (PF) and output voltages of the converters are compared. Also, THDs of grid current of each converter are compared by IEEE 519-2014 standard. In addition, current waveform and flux of SRM phases are shown. It is validated by simulations that PFC CUK converter gives better result with 9.08% THD, 0.998 PF than PFC SEPIC converter having 9.61% THD and 0.997 PF. Furthermore, both converters provide the limit defined by standards.

Published
2022

19. Modulation Scheme for Three-Phase Differential-Mode Ćuk Inverter.

Author

Mehrnami, Siamak, Mazumder, Sudip K., and Soni, Harshit

Subjects
*ELECTRIC inverters, *POWER density, *RENEWABLE energy sources, *ELECTRIC potential, *PHASE modulation
Abstract

Three-phase differential-mode inverters are single-stage inverters, which have the potential to reduce the number of devices and cost with higher power density. Among such inverter topologies, differential-mode three-phase Ćuk inverter (DTCI) has some advantage over other topologies, including modularity, lower number of switches, bidirectional power flow capability, and galvanic isolation. DTCI is a promising configuration for renewable-/alternative-energy applications with isolated and nonisolated structures. The continuous modulation scheme (CMS), which was introduced originally for the DTCI, activates all of three modules of the inverter. CMS increases the circulating power in modules and hence increases inverter power loss. This paper describes a discontinuous modulation scheme (DMS) for the DTCI which deactivates one module at a time resulting in a discontinuous operation of the inverter modules. The experimental open- and closed-loop results of DMS- and CMS-based DTCI are provided and compared. DMS reduces the circulating power, device voltage ratings, and mitigates the DTCI losses. The DTCI exhibits a nonlinear voltage gain with both DMS and CMS. It has been demonstrated that by feed-forwarding the input voltage and incorporating a static linearization method, the harmonic distortion of the output voltage is considerably reduced. [ABSTRACT FROM PUBLISHER]

Published
2016
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20. Melodic Excursions: The Brazilian cavaquinho’s global journey

Author

May, Adam John and May, Adam John

Abstract

This research project explores the long and diverse history of the cavaquinho through a combination of practical performance and archival research. This four-string soprano guitar is a ubiquitous instrument in several musical cultures and its origins may be traced to Portugal where very similar instruments have been in use since the seventeenth century. The cavaquinho, and closely related instruments, spread across the globe along routes of migration and this study will focus on four key traditions, those of Brazil, Portugal, Indonesia, and Hawaii. These historical links will be investigated through recorded performances played on the modern Brazilian cavaquinho, together with written analysis of historical and performance contexts. A diverse portfolio of recordings showcases performance practices and repertoires from the nineteenth century, through to the flourishing tradition of the twentieth century and new and emerging contemporary genres. The Brazilian cavaquinho is the instrument through which I engage with these contrasting repertoires, drawing on the richness of the instrument’s technique and performance style. The recordings are not presented as historical recreations, but as extensions of the distinct evolving traditions through the application of contemporary practices. Collaborations with renowned international practitioners feature on many of the recordings, and the creative element of this thesis extends to original arrangements and compositions. Through a combination of performance recordings, research, analysis and original arrangements and compositions, this project demonstrates how the cavaquinho is the perfect vehicle to illuminate and reinvigorate historically linked traditions and styles.

Published
2021

21. Implementation of Bridgeless Cuk Power Factor Corrector With Positive Output Voltage.

Author

Yang, Hong-Tzer, Chiang, Hsin-Wei, and Chen, Chung-Yu

Subjects
*ELECTRIC power factor, *ELECTRIC circuit design & construction, *CASCADE converters, *VOLTAGE control, *ZERO current switching
Abstract

A single-phase bridgeless Cuk ac/dc power factor correction (PFC) rectifier with positive output voltage is proposed in this paper. For low output voltage product applications, the rectifier is designed to convert high input voltage to low output voltage. Due to no bridge diodes required and thus decreased input conduction losses, the proposed rectifier efficiency can be improved. The proposed rectifier operates in discontinuous conduction mode, and the current-loop circuit is hence not needed. In addition, only a single switch is used in the rectifier to simplify the control circuit design. A simple translation method to have the positive output voltage in the Cuk converter is presented in the rectifier to reduce the component counts and the cost. The operational principles, steady-state analysis, and design procedure of the proposed rectifier are addressed in detail in this paper. Simulation and experimental results obtained from a 150-W rated prototype circuit with input of 90–130 Vrms, 60 Hz, and output of 48 Vdc have verified the validity of the proposed rectifier. [ABSTRACT FROM PUBLISHER]

Published
2015
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22. Generalized Circuit Averaging Technique for Two-Switch PWM DC-DC Converters in CCM

Author

Sumukh Surya and Sheldon S. Williamson

Subjects
Frequency response, Computer Networks and Communications, Ćuk converter, Phase margin, lcsh:TK7800-8360, 02 engineering and technology, Inductor, SEPIC, Control theory, Cuk, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Physics, CCM, circuit averaging, 020208 electrical & electronic engineering, lcsh:Electronics, 020206 networking & telecommunications, Converters, instability, Hardware and Architecture, Control and Systems Engineering, Duty cycle, LTSpice, Signal Processing, duty cycle, Pulse-width modulation, Voltage
Abstract

Design of DC-DC converters like Cuk and SEPIC, which are fourth-order converters, play a vital role in the design of electric vehicle (EV) charging systems and drivers for LED. These converters possess a unique feature of input current being continuous due to the presence of an inductor in series with the supply voltage. In the present work, a generalized approach for obtaining the frequency response of the transfer function of the duty cycle to output voltage (Gvd) for converters operating in continuous conduction mode (CCM) having two switches is proposed. A practical Cuk converter and SEPIC operating in CCM were selected and their analyses in open loop were studied using the LTSpice simulation tool. The behavior of the output voltage and inductor currents under variable ESR’s (equivalent series resistance) of inductors was studied. It was observed that Gvd of these converters was unstable. Hence, an appropriate controller to stabilize the system and achieve a proper gain margin and phase margin in closed-loop operation is required.

Published
2021
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23. Advanced ANFIS-MPPT control algorithm for sunshine photovoltaic pumping systems.

Author

Mayssa, Farhat and Sbita, Lassaad

Abstract

Recently, the solar energy has become an alternative source of energy of great importance. Divers researches and efforts have been concentrated on the photovoltaic (PV) systems efficiency improvement and the accessibility to this technology. This paper presents an intelligent approach for the improvement and optimization of the PV system efficiency. A PV system topology incorporating maximum power point tracking controller (MPPT) is studied. In order to perform this goal a special interest was focused on the neuro-fuzzy algorithm based on the Sugeno inference model. This paper presents a detailed study and design of a MPPT controller to insure a high PV system performance which can be selected for practical implementation issue. A simulation work dealing with MPPT controller, a DC/DC CùK converter feeding a DC moto-pump is achieved. Significant extracted results are given to prove the validity of the proposed overall PV pumping system. [ABSTRACT FROM PUBLISHER]

Published
2012
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24. Buck-Boost and Ĉuk topology based single phase cycloconverters with low THD and high power factor.

Author

Rubiya Binta Mustafiz, Rahman, Dhrubo, Ashfanoor Kabir, Md., Nasir Uddin, M., and Choudhury, M. A.

Abstract

Two topologies of single phase cycloconverters based on Buck-Boost and Ĉuk topologies are presented. Instead of simple switching scheme of P and N controlled rectifier-converters, high frequency switching of uncontrolled rectifiers outputs have been used with the help of Buck-boost and Ĉuk converters. The input supply is an AC source followed by a full bridge rectifier circuit, the output of which is fed to the SMPS converters. The output voltages of the proposed cycloconverters are controllable step-up and step down in nature with duty cycle control of switching regulators. Total Harmonic Distortion (THD) of the input current of the proposed circuits is minimized by input filters before the rectifier. Input power factor and efficiency of the circuits are high. The circuits exhibit such performances at variable switching frequencies and duty cycles. [ABSTRACT FROM PUBLISHER]

Published
2012
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25. Implementation of a modified incremental conductance MPPT algorithm with direct control based on a fuzzy duty cycle change estimator using dSPACE.

Author

Radjai, Tawfik, Rahmani, Lazhar, Mekhilef, Saad, and Gaubert, Jean Paul

Subjects
*ELECTRIC admittance, *MAXIMUM power point trackers, *ALGORITHMS, *PHOTOVOLTAIC power systems, *FUZZY logic
Abstract

Maximum power point tracking (MPPT) is a necessary function in all photovoltaic (PV) systems. The classic incremental conductance (IC) MPPT algorithm is widely used in the literature. However, when large changes occur in the irradiance, the performance of this algorithm is degraded. To eliminate all of the disadvantages of the classic IC algorithm, we developed a new IC controller based on a fuzzy duty cycle change estimator with direct control. A fuzzy logic estimator (FLE) is used to estimate the new duty cycle used to track the PV array maximum power point. Compared with the fixed step IC MPPT method with direct control, the proposed algorithm reaches the MPP more accurately and faster during dynamic and steady-state conditions. A controlled Cuk DC–DC converter was implemented and connected to a SunTech STP085B PV panel to verify the accuracy of the proposed method. Matlab/Simulink was used for the simulation studies. Additionally, the algorithms were digitally implemented on the dSPACE ACE1104 platform. The results obtained confirm the advantages of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Published
2014
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26. PI and Sliding Mode Control of a Cuk Converter.

Author

Zengshi Chen

Subjects
*PID controllers, *SLIDING mode control, *CONVERTERS (Electronics), *CLOSED loop systems, *ELECTRIC circuits
Abstract

Proportional-integral (PI) and sliding mode controls are combined to regulate a fourth-order Cuk converter in a continuous conduction mode. A closed-loop system is obtained with the aid of the equivalent control method. Based on the Routh-Hurwitz stability criterion and root locus, the appropriate PI gains are obtained and a stable and robust system suitable for large signal variations is achieved. The minimum or nonminimum phase behavior of the closed-loop system and the transients of the closed- loop system under step variations of various circuit parameters are analyzed. Under a wide range of operating points, the Cuk converter under the proposed controller has a load voltage tracking accuracy within ±0.05 V with a moderate maximum switching frequency of not greater than 100 KHz. The merits and demerits of the proposed controller are compared with some other controllers. [ABSTRACT FROM AUTHOR]

Published
2012
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27. Interleaved PWM Cuk Converter with Low Switching Loss.

Author

Bor-Ren Lin, Jyun-Ji Chen, Huann-Keng Chiang, and Chia-Yu Yeh

Subjects
CASCADE converters, PULSE width modulation, SWITCHING theory, ELECTRIC potential, ELECTRICAL conductors, ENGINEERING design, SIMULATION methods & models
Abstract

This paper presents an interleaved Cuk converter with turn-on switching loss reduction which is composed of two conventional Cuk converter cells and an additional resonant conductor. Two power switches are able to turn on at zero voltage switching (ZVS) operation when it operates with a duty cycle greater than 0.5. Besides, the turn-on switching loss is also reduced due to smooth current by resonant inductor when the duty cycle is smaller than 0.5 even though it is operated at hard switching. In this paper, the operational principles and design consideration are discussed; simulation and experimental results are also proposed to confirm the theoretical analysis and the advantages of the proposed converter. [ABSTRACT FROM AUTHOR]

Published
2010

28. C2000 Launchpad数字电源口袋实验平台开发.

Author

李剑波, 韩明, and 徐科军

Abstract

According to the current situation, experimental devices for power technology in colleges and universities are large, poor flexibility and high voltage level. To solve these problems, we developed a digital power experimenters kit based on the concept of pocket laboratory experiment. TI C2000 Launchpad was used as core controller. The kit also applies TMS320F28027, system board, LCD, and has a compact structure, a small size. It has functions of Buck, Boost, Cuk and Sepic. It can do the open-loop regulator experiments, peak current control experiments and dual-loop control experiment. It is portable and convenient, especially, is suitable to students in extracurricular activities and innovation competition. [ABSTRACT FROM AUTHOR]

Published
2016

29. Measurement procedures for obtaining current waveforms of non-isolated DC-DC converters

Author

Protić, Tomislav and Pelin, Denis

Subjects
strujna kliješta, current clamps, uzlazni, TECHNICAL SCIENCES. Electrical Engineering. Power Engineering, Ćukov, pretvaraĉ, Arduino current sensor, converter, shunt, Lem ureĊaj, DC-DC, Lem device, neizravni, istosmjerni, Arduino strujni senzor, Ćuk, TEHNIČKE ZNANOSTI. Elektrotehnika. Elektroenergetika, non-isolated, boost
Abstract

Mjerenjem struja istosmjernih pretvaraĉa razliĉitim metodama oĉekuju se isti ili pribliţno isti rezultati. U stvarnosti se stvaraju razliĉiti utjecaji i pojave na koje ĉovjek ne moţe utjecati, koje stvaraju razliku izmeĊu razliĉitih metoda mjerenja. Svako mjerenje ima svoju manu i prednost. Bitno je znati manu pojedine metode i pridrţavati se u ograniĉenjima mjerenja. U ovom završnom radu opisani su principi rada uzlaznog i Ćukovog pretvaraĉa, principi rada odreĊenih mjernih instrumenata, te izvršena i usporeĊena mjerenja sa istim. Prikazana je razlika izmeĊu teorijskih valnih oblika i stvarnih izmjerenih oblika. With current measuring of DC-DC converters using different methods, same or approximately the same results are expected. Various influences and phenomena are present in reality that man cannot impact on them, what creates a distinction between different measuring methods. Each measuring method has its own advantages and disadvantages. It’s important to know the disadvantages of each method and stick in measuring limitations. This undergraduate thesis describes the working principles of boost and Ćuk converters, the working principles of certain measuring instruments, performed and compared measurements. There is presented the difference between theoretical and actual measured waveforms

Published
2019

30. Primerjalna analiza stikalnih napetostnih regulatorjev SEPIC in Ćuk

Author

PERKO, JERNEJ and Topič, Marko

Subjects
meritve, primerjalna analiza, comparative analysis, Ćuk, switching regulator, measurement, simulation, preklopni regulator, simulacija, SEPIC
Abstract

V prvem delu magistrskega dela predstavim nekaj osnovnih topologij stikalnih napetostnih regulatorjev in za njih zapišem enačbe, ki so pomembne za njihovo delovanje in zmogljivost. Podrobneje predstavim topologiji Ćuk in SEPIC, za kateri zasnujem električno shemo, pri kateri se omejim na enakost komponent v vezju. Temu simuliram izkoristek, šum in tranzientni odziv ter primerjam omenjeni topologiji. Obe vezji nato tudi izdelam in na njiju izvedem meritve izkoristka, šuma in tranzientnega odziva. Na koncu izvedem primerjalno analizo izdelanih vezij, primerjam izmerjene in simulacijske rezultate, in ugotovim prednost Ćuk napetostnega regulatorja na področju izkoristka in šuma, in prednost SEPIC regulatorja pri tranzientnem odzivu in odvajanju toplote. In first part I introduce few base switching regulator topologies and write for them equations that are important for their performance. More in detail I introduce Ćuk and SEPIC topologies and draw schematic circuits for them. I then simulate those circuits and compare efficiency, noise and transient response for them. I also make this circuit in real practice and perform mentioned measurements. Then I compare simulated and measured values and find out advantages of Ćuk regulator in efficiency and noise levels, and advantages of SEPIC regulator in transient response and thermal management.

Published
2019

31. A Nonisolated Three-Port DC–DC Converter with Continuous Input and Output Currents Based on Cuk Topology for PV/Fuel Cell Applications

Author

Chellammal Nallaperumal, Balaji Chandrasekar, and Subranshu Sekhar Dash

Subjects
Computer Networks and Communications, Computer science, 020209 energy, Ćuk converter, lcsh:TK7800-8360, Topology (electrical circuits), DC–DC, 02 engineering and technology, Topology, Inductor, Cuk, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Diode, business.industry, 020208 electrical & electronic engineering, Photovoltaic system, lcsh:Electronics, Nonisolated, Port (computer networking), Renewable energy, Hardware and Architecture, Control and Systems Engineering, PV/Fuel cell, Signal Processing, Fuel cells, Continuous current, business, Three-port
Abstract

A nonisolated three-port DC&ndash, DC converter based on Cuk topology (NI-TPC) to handle the renewable sources (RS) is proposed in this paper. This converter includes two unidirectional input ports accommodating both a fuel cell (FC) and photovoltaic (PV) cell, and one output port with DC load. Due to the inductors at all the ports, it claims the advantage of continuous input and output currents. Additionally, it uses less number of switches, diodes and inductors compared with conventional &lsquo, n-1&rsquo, separate Cuk converters. Synthesis procedure for a generalized n-port DC&ndash, DC structure is explained. The derivation law based on conventional Cuk converter, operating principle, design calculation, and analysis are presented in detail, and then the analysis is validated through simulation and a 100W prototype, verifying the performance of the proposed NI-TPC converter.

Published
2019

32. Resolving practical design issues in a single-phase grid-connected GaN-FET-based differential-mode inverter

Author

Sudip K. Mazumder, Ankit Gupta, and Abhijit Kulkarni

Subjects
Computer science, Ćuk converter, Topology (electrical circuits), 02 engineering and technology, Harmonic distortion, law.invention, Solar micro-inverter, law, CUK, Control, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, High-frequency (HF) link, 0501 psychology and cognitive sciences, Parasitic extraction, Electrical and Electronic Engineering, Differential-mode inverters, 050107 human factors, Parasitics, Total harmonic distortion, 020208 electrical & electronic engineering, 05 social sciences, Photovoltaic system, Transistor, GaN field-effect transistor (FET), visual_art, Harmonics, Electronic component, visual_art.visual_art_medium, Inverter, Voltage
Abstract

Microinverters for grid-connected photovoltaic (PV) power conversion systems often require voltage boost due to the low dc voltage of the PV panels. A high-frequency (HF) transformer-isolated differential-mode ĆUK inverter (DMCI) is an attractive topology due to its inherent voltage boost capability and high power density. One of the significant operational issue of the DMCI addressed in this paper is the presence of lower order harmonic distortion in the injected grid current. It is shown that lower order odd and even harmonic voltages are generated with this topology. This problem is accentuated due to the low damping offered by the grid to harmonic voltages. A systematic low-complexity control design is proposed to address this issue. It is shown experimentally that the DMCI operates stably with effective attenuation of the lower order harmonics using the proposed design. Practical operational issues of the DMCI with fast switching GaN field-effect transistor (FET) devices are analyzed and solutions are proposed. It is shown that there can be significant HF noise generation in the DMCI with a frequency range higher than the switching frequency. Practical solutions for resolving HF issues using a combination of circuit layout design and additional passive components are proposed and validated. All of the experimental results are demonstrated on a 500-W GaN-FET-based microinverter prototype.

Published
2018
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33. Generalized Circuit Averaging Technique for Two-Switch PWM DC-DC Converters in CCM.

Author

Surya, Sumukh, Williamson, Sheldon, and Garcia, Jorge

Subjects
TRANSFER functions, ELECTRIC vehicles, PULSE width modulation transformers, VOLTAGE
Abstract

Design of DC-DC converters like Cuk and SEPIC, which are fourth-order converters, play a vital role in the design of electric vehicle (EV) charging systems and drivers for LED. These converters possess a unique feature of input current being continuous due to the presence of an inductor in series with the supply voltage. In the present work, a generalized approach for obtaining the frequency response of the transfer function of the duty cycle to output voltage (Gvd) for converters operating in continuous conduction mode (CCM) having two switches is proposed. A practical Cuk converter and SEPIC operating in CCM were selected and their analyses in open loop were studied using the LTSpice simulation tool. The behavior of the output voltage and inductor currents under variable ESR's (equivalent series resistance) of inductors was studied. It was observed that Gvd of these converters was unstable. Hence, an appropriate controller to stabilize the system and achieve a proper gain margin and phase margin in closed-loop operation is required. [ABSTRACT FROM AUTHOR]

Published
2021
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34. About bifurcations in a ZAD-Ćuk converter.

Author

Grisales Aguirre, Andres Mauricio, Amador Rodríguez, And´res Felipe, Casanova Trujillo, Simeón, Grisales Aguirre, Andres Mauricio, Amador Rodríguez, And´res Felipe, and Casanova Trujillo, Simeón

Abstract

In this paper, we make a bifurcation analysis of a mathematical model for a Ćuk converter when it is controlled by center PWM (Pulse Width Modulator) and ZAD (Zero Average Dynamics) strategy. Different nonlinear phenomena like bifurcations and chaos are reported when the parameters associated to the commutation surface are varied. Finally, the existence of chaotic behavior in the system is determined using Lyapunov exponents., En este trabajo, se realiza un análisis de bifurcaciones de un modelo matemático para un convertidor Ćuk, cuando es controlado con PWM (Pulse Width Modulator) al centro y técnica ZAD (Zero Average Dynamics). Diferentes fenómenos no lineales como bifurcaciones y caos son reportados cuando los parámetros asociados a la superficie de conmutación son variados. Finalmente, se determina la existencia de comportamiento caótico en el sistema usando los exponentes de Lyapunov.

Published
2017

35. Evaluation of Capacitor Lifetime Based on EMI and Switch Characteristics

Author

Doran, John Patrick, II

Subjects
Electrical Engineering, Capacitor Lifetime, EMI, WBG, Diagnostics, Cuk, SEPIC
Abstract

Aircraft electrical components are often misdiagnosed leading to high maintenance and upkeep costs. One potential method of increasing the accuracy of diagnostics is to use the system’s Electromagnetic Interference (EMI) to evaluate the systems condition. One of the least reliable components in electrical systems is capacitors. DC link capacitors are used as load-balancing energy storage devices used to mitigate voltage spikes and current surges subjecting them to significant stress. A model of a 3-phase inverter is analyzed to establish the impact of a capacitor’s age on its EMI. With the push for higher power in aircraft systems, the use of Wide BandGap (WBG) has increased. WBG devices are being used due their small size, greater thermal conductivity and efficiency. WBG devices offer higher switching frequencies, which can decrease the size of needed passive filtering components, thus saving in system size and cost. The faster voltage and current transients of WBG devices cause higher order harmonics in the system which may impact passive component lifetimes. Cuk and SEPIC converters utilizing both Si and SiC devices are used to evaluate the impact that WBG technology could cause in the aging of metalized film capacitors.

Published
2019

36. A Nonisolated Three-Port DC–DC Converter with Continuous Input and Output Currents Based on Cuk Topology for PV/Fuel Cell Applications.

Author

Chandrasekar, Balaji, Nallaperumal, Chellammal, and Dash, Subranshu Sekhar

Subjects
DIRECT currents, CONVERTERS (Electronics), PHOTOVOLTAIC cells, TOPOLOGY, FUEL cells
Abstract

A nonisolated three-port DC–DC converter based on Cuk topology (NI-TPC) to handle the renewable sources (RS) is proposed in this paper. This converter includes two unidirectional input ports accommodating both a fuel cell (FC) and photovoltaic (PV) cell; and one output port with DC load. Due to the inductors at all the ports, it claims the advantage of continuous input and output currents. Additionally, it uses less number of switches, diodes and inductors compared with conventional 'n-1' separate Cuk converters. Synthesis procedure for a generalized n-port DC–DC structure is explained. The derivation law based on conventional Cuk converter, operating principle, design calculation, and analysis are presented in detail, and then the analysis is validated through simulation and a 100W prototype, verifying the performance of the proposed NI-TPC converter. [ABSTRACT FROM AUTHOR]

Published
2019
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37. Stability of Peak-Current-Controlled fourth order StepUp/Down DC/DC converters

Author

Cantillo, Andrea, Marcelli, Angelo, and Femia, Nicola

Subjects
CUK, DC/DC converters, ING-IND/31 ELETTROTECNICA, SEPIC
Abstract

2009 - 2010 The topic of this dissertation is the development of models and design methods for non-isolated Switch-Mode Power Supply (SMPS). Of particular interest are DC/DC converters characterized by step up/down conversion ratio (i.e. capable to regulate the output voltage either at a lower or at a higher level with respect to the input voltage). The dissertation is mainly focused on the stability of the Single Ended Primary Inductance Converter (SEPIC) and of the Cuk converter. SEPIC and Cuk converters are both characterized by the presence of an inductor on the input port, thus resulting especially attractive for battery powered applications (e.g.. mobile GSM devices) and for PV applications. The Cuk converter features an inductor on the output port also. Hence, the Cuk converter is particularly suitable in applications where a very low-ripple output current is required (e.g. LED lighting applications). One of the main drawback of these converters is their complicated dynamic, due to the presence of four reactive elements in the power stage (input and output inductors, coupling and output capacitors). In particular, the design of stable SEPIC and Cuk using Peak-Current Control (PCC) may result extremely challenging in presence of large variations of load and line conditions. Instability phenomenon in PCC-SEPIC have been often reported in literature. It has been reported that the PCC-SEPIC is more prone to instability when operating in boost mode (i.e. when the output voltage is higher when the input voltage) and with high load currents. It has also been noted that increasing the output inductance with respect to the input one may mitigate the dynamic behaviour of the converter. However, most of the literature refers to specific examples, and results are obtained via numerical methods. On the contrary, no analytical formulations useful to identify reliable stability boundaries for PCC-SEPIC converters have been given. It is important to notice that although powerful and advanced numerical CAD tools eases the analysis and design of power supplies, analytical models have the advantage of providing the design engineer with insight about the main physical parameters which are responsible for the converter behavior. Similar considerations apply to the PCC-Cuk converter. Thus, the research presented in this dissertation has been mainly focused on: a) The development of a small signal model for PCC-SEPIC and PCC-Cuk capable of recapturing all the relevant aspects of their dynamic. b) The derivation of analytical stability conditions for PCC-SEPIC and PCC-Cuk. With reference to point a), the major improvement with respect to previous SEPIC models lies in the removal of the hypothesis of equality between the input voltage and the voltage across the coupling capacitor voltage when deriving the small signal model of the current controller. To validate the model, stability predictions obtained using numerical techniques have been tested against both simulations and experimental validations. The key role played by the ratio between output and input inductances in ensuring both stability of the converter and a good transient response in presence of step-wise variations of the input voltage has been investigated using numerical techniques. It has also been shown that for each couple of input and output inductances, there exist an optimum value of the coupling capacitor capacitance that ensures the highest damping of the voltage oscillation across the coupling capacitor in response to step-wise variations of the input voltage. With reference to point b), at first a lossless model of the SEPIC converter has been used. It is shown that analytical stability boundaries can be obtained if the impact of the output voltage variations on the coupling capacitor voltage due to an oscillation of the input voltage is neglected. This leads to a reduced-order small signal model of the SEPIC converter. It is also shown that the same reduced-order model can be used to study the Cuk converter stability. Major results for both converters are: 1. The identification of a minimum value for the coupling capacitance below which stability of the converter can not be obtained. Such minimum value increases with the load current and with the decrease of the input voltage. 2. The identification of a critical value for the current modulator gain. Such critical value depends on the voltage conversion ratio, the coupling capacitance value, the current sensor gain and on the ratio between the output and input inductances. 3. The critical value for the current modulator gain represents a minimum or a maximum allowed value depending both on the ratio between the output and input inductances and on the voltage conversion ratio. Comparisons between the analytical stability boundaries obtained via the lossless model and the numerical results given by the complete model allowed to identify the role played by resistive losses of the power components in stabilizing the converter. If losses are neglected in the complete model, numerical results show a good agreement with the analytical ones. On the contrary, when the resistive losses of the power components are considered, the analytical boundaries may result very conservative. This is more evident if the ratio between output and input inductances is lower than the voltage conversion ratio. The reason for this is that the parasitic resistances of power components may damp the converter dynamic enough to guarantee stability even though the constraints listed in point 1 and 2 are violated. Indeed, it has been determined that the minimum coupling capacitance required for stability decreases as the efficiency of the converter decreases. It should be noted that to rely on the power components parasitic elements may be dangerous, as the associated losses vary with line and load conditions, with the aging of the components and with temperature. The information given by the analytical results both provide useful guidelines for the design of a PCC-SEPIC or a PCC-Cuk converter and a valuable alert against possible instability phenomenon in high efficiency design. Experimental validations confirm the results. [edited by author] IX n.s.

Published
2011

38. Análise, projeto e implementação de conversores CC-CC com ampla faixa de conversão aplicados em iluminação de estado sólido

Author

Britto, Jonas Reginaldo de, Vieira Júnior, João Batista, Vieira, José Luiz de Freitas, Freitas, Luiz Carlos de, Farias, Valdeir José, Coelho, Ernane Antônio Alves, and Silva, Fábio Vincenzi Romualdo da

Subjects
Sepic, Cúbicos, Modelagem de conversores, Conversores elétricos, Controlador PI, Converters quadratic, Conversores quadráticos, Modeling of converters, Cuk, Solid state lighting, Cubic, PI controller, Controle digital, Iluminação elétrica, Digital control, ENGENHARIAS::ENGENHARIA ELETRICA [CNPQ], Iluminação de estado sólido, Zeta
Abstract

This work consists of the study, design and implementation of DC-DC converters, used in lighting systems based on light emitting diodes (LEDs). Can be powered by an universal AC voltage source or battery, and the current in the LEDs is controlled digitally. The main objective is to present a proposal of new step-up/down converters topologies with full conversion much higher than that of conventional converters. So, is initially presented an overview of solid-state lighting (SSL). Following is presented the study on the dynamic behavior of converters based on modeling by the method of varying state-space average, ending with the design of a digital PI controller. This work resulted in the application for a patent PI-0801425-6 filed with the INPI, which presents a new family of converters with full conversion extremely wide, called cubic converters. O presente trabalho consiste do estudo, projeto e implementação de conversores CCCC, aplicados em sistemas de iluminação de estado sólido baseado em diodos emissores de luz (LEDs). Podem ser alimentados por uma fonte de tensão alternada universal ou por uma bateria sendo que a corrente nos LEDs é controlada digitalmente. O objetivo principal é apresentar uma proposta de novas topologias de conversores abaixadores/elevadores com faixa de conversão muito maior que a dos conversores convencionais. Portanto, inicialmente é apresentada uma visão geral sobre iluminação de estado sólido (SSL). Na sequência, é apresentado o estudo sobre o comportamento dinâmico dos conversores baseado na modelagem através do método de variáveis de espaço de estados médio, finalizando com o dimensionamento de um controlador PI digital. Este trabalho resultou no pedido de patente de invenção PI-0801425-6 depositado junto ao INPI, o qual apresenta uma nova família de conversores com faixa de conversão extremamente larga, denominados de conversores cúbicos. Doutor em Ciências

Published
2009

39. Characterization of Graphite Structure by Means of Positron Annihilation, X-ray Diffraction and Laser Raman Spectroscopy

Subjects
64Cu, CuK, ORTEC, FAST-SLOW COINCIDENCE, C31024, Resolution, 235psec, Si(111)
Abstract

Characterization of graphite structure has been performed by means of positron annihilation, X-ray diffraction and laser Raman spectroscopy. Positron annihilation lifetime was shortest in HOPG (highly oriented pyrolytic graphite), i. e. 210 psec, and FWHM of the angular correlation curve was largest, i. e. 13.2 mrad. Lattice constant obtained by X-ray diffraction was 6.70 A and peak position of Raman spectroscopy was 1580 cm-1. But in degraded HOPG, isotropic graphites these values were greatly changed, namely lifetime increased and FWHM decreased. Lattice constant increased and new peak position 1355 cm-1appeared. These are considered to correspond to incomplete structures in graphites, i. e., interfaces between coherent regions, grain boundaries, pores and so on.

Published
1991

40. Metody pro řešení spínaných obvodů

Author

Kolka, Zdeněk, Ondráček, Oldřich, Kalous, Jaroslav, Kovář, Jan, Kolka, Zdeněk, Ondráček, Oldřich, Kalous, Jaroslav, and Kovář, Jan

Abstract

Tato disertační práce se zabývá simulacemi DC-DC měničů v jejich základních konfiguracích (Buck, Boost,Buck-boost, Čuk, SEPIC). V první části lze nalézt odvození přenosových funkcí Line-To-Output (LTO) a Control-To-Output (CTO) v symbolickém tvaru pro tři jednodušší konvertory (Buck, Boost, Buck-boost) s využitím známých průměrových modelů [2], [6], [11] - [15]. Z důvodu velké složitosti odvolených výrazů, byla použita metoda symbolické aproximace, která na úkor obecnosti výrazu jej podstatně zjednoduší. Průměrový model je také použit pro zjednodušení výpočetní náročnosti analýzy DC-DC měničů v časové oblasti. Pro tyto simulace byl použit jazyk VHDL-AMS. Jádrem disertační práce je metoda harmonické rovnováhy, upravená pro řešení DC-DC měničů. Jsou popsány její dvě varianty, protože podmínky a předpoklady se ve spínaných měničích pro LTO a CTO funkce velmi liší. Pro funkci LTO je možné předpokládat střídu spínacího signálu za konstantní v čase, tím i spektrum tohoto signálu je jednodušší, postačuje ve tvaru známé funkce sinc. U CTO se musí použít modulace PWM, jejíž spektrum obsahuje mnohem více kombinačních kmitočtů. Modulací PWM lze nalézt v literatuře celou řadu [58]. Pro simulace byla použita PWM modulace s uniformním vzorkováním (časově ekvidistantním) a modulací buď vzestupné nebo obou hran PWM signálu. Konečná strmost spínání PWM spínače byla modelována pomocí konečných hran PWM pulsu. V závěru je prozkoumána odchylka takto odvozených funkcí se všemi modifikacemi (typ modulace, konečné hrany) od již zmíněných průměrových modelů., The dissertation deals with simulations of the DC-DC converters in their basic configurations (Buck, Boost, Buck-boost, Cuk, SEPIC). In the first part of the thesis derivation of transfer functions Line-to-Output (LTO) and Control-To-Output (CTO) can be found. These symbolic responses are derived for three types of basic converters (Buck, Boost, Buck-boost) using well-known average model [1]. Derived expressions are very complicated. For reduction of these expressions symbolic approximation method was used, however the generality is lost. The average model was used to for decreasing the computational effort of analysis of DC-DC converters in the time domain. For these simulations VHDL-AMS language was used. The main topic of the thesis is harmonic balance method, which was adapted to DC-DC converters. Because conditions and assumptions for LTO and CTO functions are very different, harmonic balance method was derived into two variants. For obtaining of LTO response, duty cycle of switching signal can be considered as constant in time. Spectrum of this signal is simple as follows from well-known sinc function. For obtaining of CTO response PWM modulation must be used. Compared to sinc function spectrum of PWM modulation is richer (contains more combination frequencies). Many types of PWM modulation is described in [31]. For simulation PWM modulation with uniform sampling in two variants (single and double edge) was used. Non-ideal switching of PWM switch was modeled by PWM pulse with defined slew rate. Last section deals with comparison of all derived functions (LTO, CTO, modulation type, defined slew rate) with well-known averaged model.

41. Metody pro řešení spínaných obvodů

Author

Kolka, Zdeněk, Ondráček, Oldřich, Kalous, Jaroslav, Kolka, Zdeněk, Ondráček, Oldřich, and Kalous, Jaroslav

Abstract

Tato disertační práce se zabývá simulacemi DC-DC měničů v jejich základních konfiguracích (Buck, Boost,Buck-boost, Čuk, SEPIC). V první části lze nalézt odvození přenosových funkcí Line-To-Output (LTO) a Control-To-Output (CTO) v symbolickém tvaru pro tři jednodušší konvertory (Buck, Boost, Buck-boost) s využitím známých průměrových modelů [2], [6], [11] - [15]. Z důvodu velké složitosti odvolených výrazů, byla použita metoda symbolické aproximace, která na úkor obecnosti výrazu jej podstatně zjednoduší. Průměrový model je také použit pro zjednodušení výpočetní náročnosti analýzy DC-DC měničů v časové oblasti. Pro tyto simulace byl použit jazyk VHDL-AMS. Jádrem disertační práce je metoda harmonické rovnováhy, upravená pro řešení DC-DC měničů. Jsou popsány její dvě varianty, protože podmínky a předpoklady se ve spínaných měničích pro LTO a CTO funkce velmi liší. Pro funkci LTO je možné předpokládat střídu spínacího signálu za konstantní v čase, tím i spektrum tohoto signálu je jednodušší, postačuje ve tvaru známé funkce sinc. U CTO se musí použít modulace PWM, jejíž spektrum obsahuje mnohem více kombinačních kmitočtů. Modulací PWM lze nalézt v literatuře celou řadu [58]. Pro simulace byla použita PWM modulace s uniformním vzorkováním (časově ekvidistantním) a modulací buď vzestupné nebo obou hran PWM signálu. Konečná strmost spínání PWM spínače byla modelována pomocí konečných hran PWM pulsu. V závěru je prozkoumána odchylka takto odvozených funkcí se všemi modifikacemi (typ modulace, konečné hrany) od již zmíněných průměrových modelů., The dissertation deals with simulations of the DC-DC converters in their basic configurations (Buck, Boost, Buck-boost, Cuk, SEPIC). In the first part of the thesis derivation of transfer functions Line-to-Output (LTO) and Control-To-Output (CTO) can be found. These symbolic responses are derived for three types of basic converters (Buck, Boost, Buck-boost) using well-known average model [1]. Derived expressions are very complicated. For reduction of these expressions symbolic approximation method was used, however the generality is lost. The average model was used to for decreasing the computational effort of analysis of DC-DC converters in the time domain. For these simulations VHDL-AMS language was used. The main topic of the thesis is harmonic balance method, which was adapted to DC-DC converters. Because conditions and assumptions for LTO and CTO functions are very different, harmonic balance method was derived into two variants. For obtaining of LTO response, duty cycle of switching signal can be considered as constant in time. Spectrum of this signal is simple as follows from well-known sinc function. For obtaining of CTO response PWM modulation must be used. Compared to sinc function spectrum of PWM modulation is richer (contains more combination frequencies). Many types of PWM modulation is described in [31]. For simulation PWM modulation with uniform sampling in two variants (single and double edge) was used. Non-ideal switching of PWM switch was modeled by PWM pulse with defined slew rate. Last section deals with comparison of all derived functions (LTO, CTO, modulation type, defined slew rate) with well-known averaged model.

42. Metody pro řešení spínaných obvodů

Author

Kolka, Zdeněk, Ondráček, Oldřich, Kalous, Jaroslav, Kolka, Zdeněk, Ondráček, Oldřich, and Kalous, Jaroslav

Abstract

Tato disertační práce se zabývá simulacemi DC-DC měničů v jejich základních konfiguracích (Buck, Boost,Buck-boost, Čuk, SEPIC). V první části lze nalézt odvození přenosových funkcí Line-To-Output (LTO) a Control-To-Output (CTO) v symbolickém tvaru pro tři jednodušší konvertory (Buck, Boost, Buck-boost) s využitím známých průměrových modelů [2], [6], [11] - [15]. Z důvodu velké složitosti odvolených výrazů, byla použita metoda symbolické aproximace, která na úkor obecnosti výrazu jej podstatně zjednoduší. Průměrový model je také použit pro zjednodušení výpočetní náročnosti analýzy DC-DC měničů v časové oblasti. Pro tyto simulace byl použit jazyk VHDL-AMS. Jádrem disertační práce je metoda harmonické rovnováhy, upravená pro řešení DC-DC měničů. Jsou popsány její dvě varianty, protože podmínky a předpoklady se ve spínaných měničích pro LTO a CTO funkce velmi liší. Pro funkci LTO je možné předpokládat střídu spínacího signálu za konstantní v čase, tím i spektrum tohoto signálu je jednodušší, postačuje ve tvaru známé funkce sinc. U CTO se musí použít modulace PWM, jejíž spektrum obsahuje mnohem více kombinačních kmitočtů. Modulací PWM lze nalézt v literatuře celou řadu [58]. Pro simulace byla použita PWM modulace s uniformním vzorkováním (časově ekvidistantním) a modulací buď vzestupné nebo obou hran PWM signálu. Konečná strmost spínání PWM spínače byla modelována pomocí konečných hran PWM pulsu. V závěru je prozkoumána odchylka takto odvozených funkcí se všemi modifikacemi (typ modulace, konečné hrany) od již zmíněných průměrových modelů., The dissertation deals with simulations of the DC-DC converters in their basic configurations (Buck, Boost, Buck-boost, Cuk, SEPIC). In the first part of the thesis derivation of transfer functions Line-to-Output (LTO) and Control-To-Output (CTO) can be found. These symbolic responses are derived for three types of basic converters (Buck, Boost, Buck-boost) using well-known average model [1]. Derived expressions are very complicated. For reduction of these expressions symbolic approximation method was used, however the generality is lost. The average model was used to for decreasing the computational effort of analysis of DC-DC converters in the time domain. For these simulations VHDL-AMS language was used. The main topic of the thesis is harmonic balance method, which was adapted to DC-DC converters. Because conditions and assumptions for LTO and CTO functions are very different, harmonic balance method was derived into two variants. For obtaining of LTO response, duty cycle of switching signal can be considered as constant in time. Spectrum of this signal is simple as follows from well-known sinc function. For obtaining of CTO response PWM modulation must be used. Compared to sinc function spectrum of PWM modulation is richer (contains more combination frequencies). Many types of PWM modulation is described in [31]. For simulation PWM modulation with uniform sampling in two variants (single and double edge) was used. Non-ideal switching of PWM switch was modeled by PWM pulse with defined slew rate. Last section deals with comparison of all derived functions (LTO, CTO, modulation type, defined slew rate) with well-known averaged model.

43. Metody pro řešení spínaných obvodů

Author

Kolka, Zdeněk, Ondráček, Oldřich, Kalous, Jaroslav, Kolka, Zdeněk, Ondráček, Oldřich, and Kalous, Jaroslav

Abstract

Tato disertační práce se zabývá simulacemi DC-DC měničů v jejich základních konfiguracích (Buck, Boost,Buck-boost, Čuk, SEPIC). V první části lze nalézt odvození přenosových funkcí Line-To-Output (LTO) a Control-To-Output (CTO) v symbolickém tvaru pro tři jednodušší konvertory (Buck, Boost, Buck-boost) s využitím známých průměrových modelů [2], [6], [11] - [15]. Z důvodu velké složitosti odvolených výrazů, byla použita metoda symbolické aproximace, která na úkor obecnosti výrazu jej podstatně zjednoduší. Průměrový model je také použit pro zjednodušení výpočetní náročnosti analýzy DC-DC měničů v časové oblasti. Pro tyto simulace byl použit jazyk VHDL-AMS. Jádrem disertační práce je metoda harmonické rovnováhy, upravená pro řešení DC-DC měničů. Jsou popsány její dvě varianty, protože podmínky a předpoklady se ve spínaných měničích pro LTO a CTO funkce velmi liší. Pro funkci LTO je možné předpokládat střídu spínacího signálu za konstantní v čase, tím i spektrum tohoto signálu je jednodušší, postačuje ve tvaru známé funkce sinc. U CTO se musí použít modulace PWM, jejíž spektrum obsahuje mnohem více kombinačních kmitočtů. Modulací PWM lze nalézt v literatuře celou řadu [58]. Pro simulace byla použita PWM modulace s uniformním vzorkováním (časově ekvidistantním) a modulací buď vzestupné nebo obou hran PWM signálu. Konečná strmost spínání PWM spínače byla modelována pomocí konečných hran PWM pulsu. V závěru je prozkoumána odchylka takto odvozených funkcí se všemi modifikacemi (typ modulace, konečné hrany) od již zmíněných průměrových modelů., The dissertation deals with simulations of the DC-DC converters in their basic configurations (Buck, Boost, Buck-boost, Cuk, SEPIC). In the first part of the thesis derivation of transfer functions Line-to-Output (LTO) and Control-To-Output (CTO) can be found. These symbolic responses are derived for three types of basic converters (Buck, Boost, Buck-boost) using well-known average model [1]. Derived expressions are very complicated. For reduction of these expressions symbolic approximation method was used, however the generality is lost. The average model was used to for decreasing the computational effort of analysis of DC-DC converters in the time domain. For these simulations VHDL-AMS language was used. The main topic of the thesis is harmonic balance method, which was adapted to DC-DC converters. Because conditions and assumptions for LTO and CTO functions are very different, harmonic balance method was derived into two variants. For obtaining of LTO response, duty cycle of switching signal can be considered as constant in time. Spectrum of this signal is simple as follows from well-known sinc function. For obtaining of CTO response PWM modulation must be used. Compared to sinc function spectrum of PWM modulation is richer (contains more combination frequencies). Many types of PWM modulation is described in [31]. For simulation PWM modulation with uniform sampling in two variants (single and double edge) was used. Non-ideal switching of PWM switch was modeled by PWM pulse with defined slew rate. Last section deals with comparison of all derived functions (LTO, CTO, modulation type, defined slew rate) with well-known averaged model.

44. Hybrid Multiport Converter for High Step-Up Renewable Energy Applications

Author

Oleksandr Bondarenko, Anatoliy Prystupa, Sanjeevikumar Padmanaban, J G Nataraj Barath, Serhii Stepenko, and A. Soundarrajan

Subjects
multi-output, High-gain antenna, Computer science, business.industry, DC-DC converters, quadratic boost converter, Ćuk converter, multi-port converter, Quadratic boost converter, Network topology, SEPIC, Power (physics), Renewable energy, Cuk, Electronic engineering, business, Power control
Abstract

In this paper, a hybrid converter configuration is proposed suitable for high step-up renewable energy applications. The proposed topologies are derived by combining quadratic boost converter with Cuk and SEPIC converter. The proposed topologies are capable of producing high gain power conversion with single power control switch. The proposed topologies are suitable for applications requiring DC-DC multi-output converter.

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