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1

FRACTIONAL ORDER SMC FOR DC-DC BUCK CONVERTER  

Directory of Open Access Journals (Sweden)

Full Text Available This paper proposed a fractional order sliding mode control for DC-DC buck converter. The traditionally P, PI and PID type linear controllers are used to control the voltages. The DC-DC buck converter is nonlinear and time variant in nature. To control such system variable structure control based sliding mode controller (SMC is used. The fractional order sliding mode control method not only eliminates chattering problem of integer order SMC, it gives good transient response of the system. The simulation results shows fractional order SMC gives fast response compared to integer order SMC.

S. D. Jagdale

2013-11-01

2

Hybrid posicast controller for a DC-DC buck converter  

Directory of Open Access Journals (Sweden)

Full Text Available A new Posicast compensated hybrid controller for the DC-DC Buck converter is investigated. Posicast is a feed forward compensator, which eliminates the overshoot in the step response of a lightly damped system. However, the traditional method is sensitive to variations in natural frequency. The new method described here reduces this undesirable sensitivity by using Posicast within the feedback loop. Design of the Posicast function is independent of computational delay. The new controller results in a lower noise in the control signal, when compared to a conventional PID controller.

Kaithamalai Udhayakumar

2008-01-01

3

A novel bidirectional multilevel boost-buck dc-dc converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A novel noninverting boost-buck dc-dc converter topology is presented, applicable when both sides of the converter need to have the same grounding. It is based on the back-to-back connection of two n-level diode-clamped converter legs, and allows bidirectional power flow. A simplified topology is proposed for unidirectional power flow applications. Two new pulse width modulation strategies with different advantages are proposed to operate the converter guaranteeing dc-lin...

Busquets Monge, Sergio; Alepuz Mene?ndez, Salvador; Bordonau Farrerons, Jose?

2009-01-01

4

Integrated Circuit of CMOS DC-DC Buck Converter with Differential Active Inductor  

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In this paper, we propose a new design of DC-DC buck converter (BC), which the spiral inductor is replaced by a differential gyrator with capacitor load (gyrator-C) implemented in 0.18um CMOS process. The gyrator-C transforms the capacitor load (which is the parasitic capacitor of MOSFETS) to differential active inductor DAI. The low-Q value of DAI at switching frequency of converter (few hundred kHz) is boosted by adding a negative impedance converter (NIC). The transistor parameters of DAI ...

2011-01-01

5

A New Zero Voltage Switching Buck-Boost Type DC-DC Converter  

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Full Text Available In this paper, a new zero voltage switching isolated buck-boost DC-DC converter with active clamp circuit is proposed. The active clamp circuit in this converter not only absorbs voltage spikes across the main switch but also provides soft switching conditions for all switches. All switches are PWM controlled which simplifies the control implementation. One of the main advantages of this converter is the that it operating can operate at high power levels while soft switching conditions exist in both buck and boost modes of converter operation. Since this converter can operate over a wide input voltage range, it can be employed in power factor correction. The experimental results obtained from a 150W prototype circuit operating at 100KHz are presented to confirm the integrity of the proposed circuit.

Majid Delshad

2010-03-01

6

Design of Controllers for Single-Input Dual-Output Synchronous DC-DC Buck Converter  

Directory of Open Access Journals (Sweden)

Full Text Available Design and control techniques for a Single Input Dual Output (SIDO Synchronous DC-DC Buck Converter are presented. The advantage of this converter eliminates one MOSFET switch and its drive circuitry when compared to the conventional converter and in this system both output voltages are generated by the same integrated power converter. A Genetic Algorithm assisted PI controller is designed to maintain the output voltages to a constant value against load and line variations and compared with existing PI controller. The parameters of the controller are designed using various techniques like SISOTOOL (GUI, Internal Model Control and Binary Genetic Algorithm. The Discrete PI controller is also developed for the above converter. All the controllers are simulated using MATLAB and their performances are compared in terms of Peak overshoot, Rise time and Settling time. The system is also developed using real components and the results are obtained in open loop mode.

S.Augustilindiya

2013-08-01

7

Integrated Circuit of CMOS DC-DC Buck Converter with Differential Active Inductor  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we propose a new design of DC-DC buck converter (BC, which the spiral inductor is replaced by a differential gyrator with capacitor load (gyrator-C implemented in 0.18um CMOS process. The gyrator-C transforms the capacitor load (which is the parasitic capacitor of MOSFETS to differential active inductor DAI. The low-Q value of DAI at switching frequency of converter (few hundred kHz is boosted by adding a negative impedance converter (NIC. The transistor parameters of DAI and NIC can be properly chosen to achieve the desirable value of equivalent inductance L (few tens H, and the maximum-Q value at the switching frequency, and thus the efficiency of converter is improved. Experimental results show that the converter supplied with an input voltage of 1V, provides an output voltage of 0.74V and output ripple voltage of 10mV at 155 kHz and Q-value is maximum (#8776;4226 at this frequency.

Kaoutar Elbakkar

2011-11-01

8

An optimal current observer for predictive current controlled buck DC-DC converters.  

Science.gov (United States)

In digital current mode controlled DC-DC converters, conventional current sensors might not provide isolation at a minimized price, power loss and size. Therefore, a current observer which can be realized based on the digital circuit itself, is a possible substitute. However, the observed current may diverge due to the parasitic resistors and the forward conduction voltage of the diode. Moreover, the divergence of the observed current will cause steady state errors in the output voltage. In this paper, an optimal current observer is proposed. It achieves the highest observation accuracy by compensating for all the known parasitic parameters. By employing the optimal current observer-based predictive current controller, a buck converter is implemented. The converter has a convergently and accurately observed inductor current, and shows preferable transient response than the conventional voltage mode controlled converter. Besides, costs, power loss and size are minimized since the strategy requires no additional hardware for current sensing. The effectiveness of the proposed optimal current observer is demonstrated experimentally. PMID:24854061

Min, Run; Chen, Chen; Zhang, Xiaodong; Zou, Xuecheng; Tong, Qiaoling; Zhang, Qiao

2014-01-01

9

An Optimal Current Observer for Predictive Current Controlled Buck DC-DC Converters  

Directory of Open Access Journals (Sweden)

Full Text Available In digital current mode controlled DC-DC converters, conventional current sensors might not provide isolation at a minimized price, power loss and size. Therefore, a current observer which can be realized based on the digital circuit itself, is a possible substitute. However, the observed current may diverge due to the parasitic resistors and the forward conduction voltage of the diode. Moreover, the divergence of the observed current will cause steady state errors in the output voltage. In this paper, an optimal current observer is proposed. It achieves the highest observation accuracy by compensating for all the known parasitic parameters. By employing the optimal current observer-based predictive current controller, a buck converter is implemented. The converter has a convergently and accurately observed inductor current, and shows preferable transient response than the conventional voltage mode controlled converter. Besides, costs, power loss and size are minimized since the strategy requires no additional hardware for current sensing. The effectiveness of the proposed optimal current observer is demonstrated experimentally.

Run Min

2014-05-01

10

A fast novel soft-start circuit for peak current-mode DC—DC buck converters  

International Nuclear Information System (INIS)

A fully integrated soft-start circuit for DC—DC buck converters is presented. The proposed high speed soft-start circuit is made of two sections: an overshoot suppression circuit and an inrush current suppression circuit. The overshoot suppression circuit is presented to control the input of the error amplifier to make output voltage limit increase in steps without using an external capacitor. A variable clock signal is adopted in the inrush current suppression circuit to increase the duty cycle of the system and suppress the inrush current. The DC—DC converter with the proposed soft-start circuit has been fabricated with a standard 0.13 ?m CMOS process. Experimental results show that the proposed high speed soft-start circuit has achieved less than 50 ?s start-up time. The inductor current and the output voltage increase smoothly over the whole load range. (semiconductor integrated circuits)

2013-02-01

11

MCU Controlled DC-DC Buck/Boost Converter for Supercapacitors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work is focused on DC to DC conversion, what is a crucial function to enable the use of supercapacitors for energy storage. A theoretical study and comparison of methods, algorithms and techniques for software controlled DC-DC converters have been used to develop a system what can step up or down a DC variable voltage and transform it into a steady state voltage. As a result a new control theory based on Bang-Bang control has been developed with an ARM LPC1768 processor. It was implement...

Querol Borra?s, Jorge

2012-01-01

12

A Comparative study of Analog and digital Controller On DC/DC Buck-Boost Converter Four Switch for Mobile Device Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

this paper presents comparative performance between Analog and digital controller on DC/DC buck-boost converter four switch. The design of power electronic converter circuit with the use of closed loop scheme needs modeling and then simulating the converter using the modeled equations. This can easily be done with the help of state equations and MATLAB/SIMULINK as a tool for simulation of those state equations. DC/DC Buckboost converter in this study is operated in buck (step-down) and boost ...

Benlafkih Abdessamad; Krit Salah-Ddine; Chafik Elidrissi Mohamed

2013-01-01

13

Identifier-based adaptive neural dynamic surface control for uncertain DC-DC buck converter system with input constraint  

Science.gov (United States)

In this paper, an identifier-based adaptive neural dynamic surface control (IANDSC) is proposed for the uncertain DC-DC buck converter system with input constraint. Based on the analysis of the effect of input constraint in the buck converter, the neural network compensator is employed to ensure the controller output within the permissible range. Subsequently, the constrained adaptive control scheme combined with the neural network compensator is developed for the buck converter with uncertain load current. In this scheme, a newly presented finite-time identifier is utilized to accelerate the parameter tuning process and to heighten the accuracy of parameter estimation. By utilizing the adaptive dynamic surface control (ADSC) technique, the problem of "explosion of complexity" inherently in the traditional adaptive backstepping design can be overcome. The proposed control law can guarantee the uniformly ultimate boundedness of all signals in the closed-loop system via Lyapunov synthesis. Numerical simulations are provided to illustrate the effectiveness of the proposed control method.

Chen, Qiang; Ren, Xuemei; Oliver, Jesus Angel

2012-04-01

14

A STUDY OF ADAPTIVE FEED FORWARD AND FEEDBACK CONTROL METHODS FOR SLIDING MODE CONTROLLED DC-DC BUCK CONVERTERS  

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Full Text Available Switching frequency acts as a major role, while applying sliding mode control to dc-dc buck converter, switching frequency is affected by line and load variations. To reduce switching frequency deviation to line and load variations, an adaptive feed forward control is used, that varies hysteresis band according to the change of input voltage. Several methods of varying hysteresis band of the hysteresis modulator are possible. In this work adjusting the power supply is to be considered. An adaptive feedback control scheme that varies the control parameters (i.e. sliding coefficient according to the change of output load is proposed. This paper presents a complete investigation into the problem and gives the effectiveness of the desired solutions. In this method implementing the proposed adaptive control strategies are discussed, simulation results gives that the adaptive control methods are capable of reducing the switching frequency variations, simulation have been done in MATLAB /Simulink to verify the results.

H. N. Nagaraj

2012-05-01

15

DCM, FSM, dead time and width controllers for a high frequency high efficiency buck DC-DC converter over a wide load range  

International Nuclear Information System (INIS)

This paper presents a width controller, a dead time controller, a discontinuous current mode (DCM) controller and a frequency skipping modulation (FSM) controller for a high frequency high efficiency buck DC-DC converter. To improve the efficiency over a wide load range, especially at high switching frequency, the dead time controller and width controller are applied to enhance the high load efficiency, while the DCM controller and FSM controller are proposed to increase the light load efficiency. The proposed DC-DC converter controllers have been designed and fabricated in the Chartered 0.35 ?m CMOS process, and the measured results show that the efficiency of the buck DC-DC converter is above 80% over a wide load current range from 8 to 570 mA, and the peak efficiency is 86% at 10 MHz switching frequency. (semiconductor integrated circuits)

2010-08-01

16

Radiation Effects on DC-DC Converters  

Science.gov (United States)

In this work, several DC-DC converters were designed and built. The converters are Buck Buck-Boost, Cuk, Flyback, and full-bridge zero-voltage switched. The total ionizing dose radiation and single event effects on the converters were investigated. The experimental results for the TID effects tests show that the voltages of the Buck Buck-Boost, Cuk, and Flyback converters increase as total dose increased when using power MOSFET IRF250 as a switching transistor. The change in output voltage with total dose is highest for the Buck converter and the lowest for Flyback converter. The trend of increase in output voltages with total dose in the present work agrees with those of the literature. The trends of the experimental results also agree with those obtained from PSPICE simulation. For the full-bridge zero-voltage switch converter, it was observed that the dc-dc converter with IRF250 power MOSFET did not show a significant change of output voltage with total dose. In addition, for the dc-dc converter with FSF254R4 radiation-hardened power MOSFET, the output voltage did not change significantly with total dose. The experimental results were confirmed by PSPICE simulation that showed that FB-ZVS converter with IRF250 power MOSFET's was not affected with the increase in total ionizing dose. Single Event Effects (SEE) radiation tests were performed on FB-ZVS converters. It was observed that the FB-ZVS converter with the IRF250 power MOSFET, when the device was irradiated with Krypton ion with ion-energy of 150 MeV and LET of 41.3 MeV-square cm/mg, the output voltage increased with the increase in fluence. However, for Krypton with ion-energy of 600 MeV and LET of 33.65 MeV-square cm/mg, and two out of four transistors of the converter were permanently damaged. The dc-dc converter with FSF254R4 radiation hardened power MOSFET's did not show significant change at the output voltage with fluence while being irradiated by Krypton with ion energy of 1.20 GeV and LET of 25.97 MeV-square cm/mg. This might be due to fact that the device is radiation hardened.

Zhang, De-Xin; AbdulMazid, M. D.; Attia, John O.; Kankam, Mark D. (Technical Monitor)

2001-01-01

17

Diseño estático de un convertidor DC/DC reductor-elevador bidireccional / Bidirectional buck-boost dc/dc converter static design  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Se presenta el diseño estático de un convertidor reductor-elevador bidireccional con tres conmutadores y conexión en cascada. La principal aplicación del convertidor es la administración de baterías en sistemas de alimentación ininterrumpida, controlando el flujo de energía y regulando la tensión de [...] alimentación DC durante los diferentes modos de operación de la batería como fuente y sumidero. Abstract in english This paper shows a buck-boost converter static design with 3 switches and cascade connection. The main application of the converter is the battery management on uninterruptible power supplies, controlling energy flow and regulating the DC supply voltage for the different battery operation modes as s [...] ource and sink.

González Valencia, Marcela; Alzate Gómez, Alfonso.

18

Hybrid battery with bi-directional DC/DC converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bi-directional buck-boost DC/DC converterfor hybrid battery is described in this paper. The firstpart of the paper is aimed at concept of hybrid battery;main advance compared to conventional accumulatoris explained there. Control circuit with UC3637 andpower circuit of the converter are described in thesecond part of the paper. Experimental results frommeasuring of converter are mentioned in the last part.

2010-01-01

19

An Integrated High Efficiency DC-DC Converter in 65 nm CMOS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis work describes the implementation perspective of an integrated high efficiency DC-DC converter implemented in 65 nm CMOS. The implemented system employs the Buck converter topology to down-convert the input battery voltages. This converter offers its use as a power management unit in portable battery operated devices. This thesis work includes the description of a basic Buck converter along with the various key equations involved which describe the Buck operation as well as are us...

Manh, Vir Varinder

2010-01-01

20

Recognition of dynamic patterns in dc-dc switching converters  

Science.gov (United States)

Techniques are presented for analyzing the dynamic patterns of power flow in high-frequency dc-dc switching converters. Emphasis is placed on exploring methods for developing reduced-order models of power electronic circuits for simulation and state-space averaging. Tools from selective modal analysis are used to develop the dynamic pattern recognition algorithm that facilitates the classification of circuit modules. The algorithm is intended for the analysis of converters derived from the canonical switching call, i.e., the buck, boost, and flyback converters.

Leeb, Steven B.; Kirtley, James L.; Verghese, George C.

 
 
 
 
21

Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1  

Science.gov (United States)

The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

Lee, F. C.; Mahmoud, M. F.; Yu, Y.

1980-01-01

22

Radiation-Tolerant DC-DC Converters  

Science.gov (United States)

A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

2012-01-01

23

Parallel Linear–Assisted DC-DC Switching Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Linear-assisted DC-DC converters or linear-switching hybrid DC–DC converters are power supply structures in which some important advantages from linear regulators and DC-DC switching converters converge. Normally, in linear assisted converters a series linear regulator is used in order to provide a constant ripple-free output voltage. However, this article shows the proposal of a linear–assisted DCDC converter or linear–&–switching hybrid converter including a parallel linear re...

Marti?nez Garci?a, Herminio; Grau Saldes, Antoni; Bolea Monte, Yolanda; Ga?miz Caro, Juan

2011-01-01

24

Examination of different spread spectrum techniques for EMI suppression in dc/dc converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Examination of different switching frequency modulation techniques (SFMT) for electromagnetic interference (EMI) suppression in dc/dc power converters is presented. The techniques under investigation are sinusoidal (with modulating frequencies 2 kHz and 5 kHz), pseudo-random (with uniform and normal probability distributions of modulating signal) and pseudo-chaotic SFMT. All the techniques are applied to digitally-controlled buck converter of Microchip dsPICDEM SMPS Buck Development Board. Fr...

Jankovskis, J.; Stepins, D.; Tjukovs, S.; Pikulins, D.

2008-01-01

25

Robust DC/DC converter control for polymer electrolyte membrane fuel cell application  

Science.gov (United States)

This study investigates a robust controller in regulating the pulse width modulation (PWM) of a DC/DC converter for a polymer electrolyte membrane fuel cell (PEMFC) application. A significant variation in the output voltage of a PEMFC depends on the power requirement and prevents a PEMFC from directly connecting to a subsequent power bus. DC/DC converters are utilized to step-up or step-down voltage to match the subsequent power bus voltage. In this study, a full dynamic model, which includes a PEMFC and boost and buck DC/DC converters, is developed under MATLAB/Simulink environment for control. A robust PWM duty ratio control for the converters is designed using time delay control (TDC). This control enables state variables to accurately follow the dynamics of a reference model using time-delayed information of plant input and output information within a few sampling periods. To prove the superiority of the TDC performance, traditional proportional-integral control (PIC) and model predictive control (MPC) are designed and implemented, and the simulation results are compared. The efficacies of TDC for the PEMFC-fed PWM DC/DC converters are validated through experimental test results using a 100 W PEMFC as well as boost and buck DC/DC converters.

Wang, Ya-Xiong; Yu, Duck-Hyun; Chen, Shi-An; Kim, Young-Bae

26

Sliding Mode Control of Dc-Dc Boost Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Control of Dc-Dc boost converter is a complex task due to the nonlinearity inherent in the converter and introduced by the external changes. A robust sliding mode controller for the control of Dc-Dc boost converter were described in this study. Dynamic equations describing the boost converter are derived and sliding mode controller is designed. The robustness of the sliding mode controlled boost converter system is tested for step load changes and input voltage variations. The computer-aided ...

Hanifi Guldemir

2005-01-01

27

Early Oscillation Detection for DC/DC Converter Fault Diagnosis  

Science.gov (United States)

The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

Wang, Bright L.

2011-01-01

28

Early Oscillation Detection Technique for Hybrid DC/DC Converters  

Science.gov (United States)

Oscillation or instability is a situation that must be avoided for reliable hybrid DC/DC converters. A real-time electronics measurement technique was developed to detect catastrophic oscillations at early stages for hybrid DC/DC converters. It is capable of identifying low-level oscillation and determining the degree of the oscillation at a unique frequency for every individual model of the converters without disturbing their normal operations. This technique is specially developed for space-used hybrid DC/DC converters, but it is also suitable for most of commercial and military switching-mode power supplies. This is a weak-electronic-signal detection technique to detect hybrid DC/DC converter oscillation presented as a specific noise signal at power input pins. It is based on principles of feedback control loop oscillation and RF signal modulations, and is realized by using signal power spectral analysis. On the power spectrum, a channel power amplitude at characteristic frequency (CPcf) and a channel power amplitude at switching frequency (CPsw) are chosen as oscillation level indicators. If the converter is stable, the CPcf is a very small pulse and the CPsw is a larger, clear, single pulse. At early stage of oscillation, the CPcf increases to a certain level and the CPsw shows a small pair of sideband pulses around it. If the converter oscillates, the CPcf reaches to a higher level and the CPsw shows more high-level sideband pulses. A comprehensive stability index (CSI) is adopted as a quantitative measure to accurately assign a degree of stability to a specific DC/DC converter. The CSI is a ratio of normal and abnormal power spectral density, and can be calculated using specified and measured CPcf and CPsw data. The novel and unique feature of this technique is the use of power channel amplitudes at characteristic frequency and switching frequency to evaluate stability and identify oscillations at an early stage without interfering with a DC/DC converter s normal operation. This technique eliminates the probing problem of a gain/phase margin method by connecting the power input to a spectral analyzer. Therefore, it is able to evaluate stability for all kinds of hybrid DC/DC converters with or without remote sense pins, and is suitable for real-time and in-circuit testing. This frequency-domain technique is more sensitive to detect oscillation at early stage than the time-domain method using an oscilloscope.

Wang, Bright L.

2011-01-01

29

High efficiency interleaved bi-directional ZVS DC-DC converter  

International Nuclear Information System (INIS)

A high efficiency interleaved bi-directional ZVS DC-DC converter is presented in this paper. This converter can be operated in both buck and boost mode. CoolMOS is used as a power device to achieve low conduction losses and fast turn off. The value of inductance is selected such that the CoolMOS drain-to-source voltage always falls to zero before it turns on and ZVS is achieved. Multiphase interleaved inductors are used to achieve high power and low ripple currents. Converter is operated at 50kHz and MATLAB Simulink simulation is performed. 6kW prototype converter is implemented in buck mode and simulation results are verified.

2013-06-10

30

Multiple-output Class E Isolated dc-dc Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a multiple output class-E isolated dc-dc converter that regulates the output voltages at fixed switching frequency. The two output converter is simulated at operating frequency of 5 MHz. The converter output power is 40 W and the output voltages are 15 V and 5 V. All the switches operate at zero voltage switching (ZVS) conditions for the full load range. The circuit configuration is simple with small passive components which reduce the size of the converter. The circuit al...

Pavlovic, Zoran; Oliver Rami?rez, Jesu?s Angel; Alou Cervera, Pedro; Garci?a Sua?rez, Oscar; Prieto Lo?pez, Roberto; Cobos Ma?rquez, Jose? Antonio

2010-01-01

31

Design and implementation of fully-integrated inductive DC-DC converters in standard CMOS  

CERN Document Server

CMOS DC-DC Converters aims to provide a comprehensive dissertation on the matter of monolithic inductive Direct-Current to Direct-Current (DC-DC) converters. For this purpose seven chapters are defined which will allow the designer to gain specific knowledge on the design and implementation of monolithic inductive DC-DC converters, starting from the very basics.

Wens, Mike

2011-01-01

32

Design of DC-DC Converter for Flash Memory IPs  

Directory of Open Access Journals (Sweden)

Full Text Available A DC-DC converter for flash memory IPs performing erasing by the FN (Fowler-Nordheim tunneling and programming by the CHEI (channel hot electron injection is designed in this paper. For the DC-DC converter for flash memory IPs using a dual voltage of VDD (=1.5V±0.15V/VRD (=3.1V±0.1V, a scheme of using VRD (Read Voltage instead of VDD is proposed to reduce the pumping stages and pumping capacitances of its charge pump circuit. VRD (=3.1V±0.1V is a regulated voltage by a voltage regulator with an external voltage of 5V, which is used as the WL activation voltage in the read mode and an input voltage of the charge pump. The designed DC-DC converter outputs positive voltages of VP6V (=6V, VP8V (=8V and VP9V(=9V; and a negative voltage of  VM8V (=-8V in the write mode.

Li-yan Jin

2013-01-01

33

A Pedagogical Approach for Modeling and Simulation of Switching Mode DC-DC Converters for Power Electronics Course  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The power electronics course is a rather challenging subject for instructors and undergraduate students pursuing Bachelor’s Degree in Electrical Engineering. To enhance teaching effectiveness and motivate self-learning capabilities of the students, this paper presents a pedagogical approach for mathematical modeling and simulation of switching mode DC-DC converters. The Buck and Boost converters are analyzed as benchmark systems to study the power converter modeling methodologies. And a...

Han Yang

2012-01-01

34

Distributed maximum power point tracking in photovoltaic applications: active bypass DC/DC converter / Seguimiento del punto de máxima potencia distribuida en aplicaciones fotovoltaicas: convertidor DC/DC para desviación activa  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish Se propone una estructura de desvío activo para maximizar la producción de potencia en sistemas fotovoltaicos bajo condiciones irregulares de operación, comparando su eficiencia con soluciones individuales y distribuidas basadas en convertidores DC/DC convencionales. Los análisis y simulaciones real [...] istas demuestran las ventajas del nuevo convertidor de desvío activo sobre soluciones basadas en convertidores Boost, Buck y Buck-Boost. Abstract in english An active bypass structure is proposed to maximize the power production in photovoltaic modules under mismatched conditions. Its efficiency is compared with single and distributed maximum power point tracking solutions based on conventional DC/DC structures. The analysis and simulations performed un [...] der realistic assumptions demonstrate the benefits of the novel active bypass converter over solutions based on Boost, Buck or Buck-Boost converters.

Ramos-Paja, Carlos Andrés; Gira, Roberto; Arango Zuluaga, Eliana Isabel.

35

Modified Multiport Dc-Dc Converter Topology For Smart Grid  

Directory of Open Access Journals (Sweden)

Full Text Available The development of a Solid State Transformer (SST that incorporates a DC-DC multiport converter to integrate both photovoltaic (PV power generation and battery energy storage is presented in this dissertation. The DC-DC stage is based on a quad active-bridge (QAB converter which not only provides isolation for the load, but also for the PV and storage. The AC-DC stage is implemented with a pulse-widthmodulated (PWM single phase rectifier. A unified gyrator-based average model is developed for a general multi-active-bridge (MAB converter controlled through phase-shift modulation (PSM. Expressions to determine the power rating of the MAB ports are also derived. The developed gyrator-based average model is applied to the QAB converter for faster simulations of the proposed SST during the control design process as well for deriving the state-space representation of the plant. Both linear quadratic regulator (LQR and singleinput-single-output (SISO types of controllers are designed for the DC-DC stage. A novel technique that complements the SISO controller by taking into account the cross coupling characteristics of the QAB converter is also presented herein. Cascaded SISO controllers are designed for the AC-DC stage. The QAB demanded power is calculated at the QAB controls and then fed into the rectifier controls in order to minimize the effect of the interaction between the two SST stages. The dynamic performance of the designed control loops based on the proposed control strategies are verified through extensive simulation of the SST average and switching models.

Dhamodharan Shanmugam

2013-10-01

36

Input interface requirements on board mounted DC/DC converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis has been carried out on behalf of the department of Power Modules at Ericsson. In a telecom system interface A is a physical point between the power supply system and the telecommunication equipment described in a European standard called ETSI EN 300 132-2. This interface is also described in the American standard ATIS-0600315.2007. For board-mounted products, such as DC/DC converters, a well-defined input interface description is lacking. The goal of this thesis was to evaluate ...

Croneba?ck, Alexandra

2013-01-01

37

Direct switching control of DC-DC power electronic converters using hybrid system theory  

Energy Technology Data Exchange (ETDEWEB)

A direct switching control (DSC) scheme for power electronics converters was described. The system was designed for use in both traditional and renewable energy applications as well as in electric drive vehicles. The proposed control scheme was based on a detailed hybrid system converter model that used model predictive control (MPC), piecewise affine (PWA) approximations and constrained optimal control methods. A DC-DC converter was modelled as a hybrid machine. Switching among different modes of the DC-DC converter were modelled as discrete events controlled by the hybrid controller. The modelling scheme was applied to a Buck converter. The DSC was used to control the switch of the power converter based on a hybrid machine model. Results of the study showed that the method can be used to regulate output voltage and inductor currents. The method also provides fast transient responses and effectively regulates both currents and voltage. The controller can be used to provide immediate responses to dynamic disturbances and output voltage fluctuations. 23 refs., 7 figs.

Zhao, J.; Lin, F. [Wayne State Univ., Detroit, MI (United States). Dept. of Electrical and Computer Engineering; Wang, C. [Wayne State Univ., Detroit, MI (United States). Dept. of Electrical and Computer Engineering; Wayne State Univ., Detroit, MI (United States). Div. of Engineering Technology

2010-07-01

38

Very High Frequency Half Bridge DC/DC Converter  

DEFF Research Database (Denmark)

This paper presents the first, off chip, class DE (resonant half bridge) converter working in the Very High Frequency (VHF) range. The benefits of using half bridge circuits both in the inverter and rectifier part of a VHF resonant dc/dc converter are analyzed and design equations for all components in the power stage are given. The circuit has been simulated to verify the accuracy of the presented equations and an efficiency of 89% has been shown. A prototype has been implemented with self-oscillating resonant gate drives driving the switches. The prototype has been used to drive an LED string and shows an efficiency of 85% at 29 MHz with 130 V input and 13.4 W output. The efficiency was above 82% in the range 110-150 V input with output power between 10.3 W and 16.5 W

Madsen, Mickey Pierre; Knott, Arnold

2014-01-01

39

A Comparison of Half Bridge & Full Bridge Isolated DC-DC Converters for Electrolysis Application  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a comparison of half bridgeand full bridge isolated, soft-switched, DC-DC converters forElectrolysis application. An electrolyser is a part of renewableenergy system which generates hydrogen from water electrolysisthat used in fuel cells. A DC-DC converter is required to coupleelectrolyser to system DC bus. The proposed DC-DC converter isrealized in both full-bridge and half-bridge topology in order toachieve zero voltage switching for the power switches and toregulate the...

2011-01-01

40

NPC four-quadrant DC-DC converter applying Integrated-Voltage-Control method; Den`atsu sekibunchi seigyo hoshiki wo mochiita NPC yonshogen DC-DC converter  

Energy Technology Data Exchange (ETDEWEB)

A switching mode DC-DC converter applying the Integrated-Voltage-Control method works stably and has no steady state error. The basic circuit of this converter consists of an error voltage integrator and a hysteresis comparator which drives a power transistor to on/off. The DC-DC converter circuit can be extended to a Four-Quadrant DC-DC converter circuit. This Four-Quadrant converter has four hysteresis comparators driven in parallel by an error voltage integrator, and each comparator drives a prearranged power transistor engaged with one of the four quadrants of the converter operation on the voltage- current plane. In this paper, we propose a new NPC (Neutral- Point- Clamped) Multi- Level Four- Quadrant DC-DC converter applying the Integrated-Voltage-Control method, developed from the Four-Quadrant DC-DC converter driving circuit. This new NPC converter consists of eight hysteresis comparators driven in parallel by an error voltage integrator. There are eight operating regions in this new converter and one of eight power transistors is driven by one of eight hysteresis comparators to on/off in each prearranged region. The neutral-point voltage can be kept at a constant value by a new restrain control scheme also proposed in this paper. It has been confirmed experimentally that the new NPC converter has no short circuit mode, no steady state error, and a quick response time. 11 refs., 12 figs., 2 tabs.

Okui, H. [Osaka Polytechnic College, Osaka (Japan); Irie, H. [Osaka Electro-Communication University, Osaka (Japan)

1998-02-01

 
 
 
 
41

A Novel Bidirectional DC-DC Converter With Flyback Snubber For Hybrid Electric Vehicles  

Directory of Open Access Journals (Sweden)

Full Text Available Hybrid electric Vehicles combine the benefits of engine, electric motor and batteries to provide improved fueleconomy. A converter is needed in hybrid Electric Vehicle for charging and discharging of the batteries. So a charging anddischarging can be combined in one circuit topology known as bidirectional DC-DC converter. Here the output is completelyisolated from input, so an isolated bidirectional Dc-DC converter is used. In the bidirectional DC-DC converter, there occursovervoltage and overcurrent stress, which can be reduced by snubber circuits. Various technologies such as RCD, active clampand flyback snubber for bidirectional DC-DC converter are compared. The bidirectional DC-DC converter with flyback snubberis explained in detail. The simulations are carried out using Simulink/MATLAB 7.6.0 (R2009b package. The hardware is doneusing PIC16F877A, a microcontroller to generate the PWM pulses for the MOSFET switches so that harmonics in the circuit canbe reduced.

DIVYA K.NAIR

2013-06-01

42

Optimization of DC-DC Converters for Improved Electromagnetic Compatibility With High Energy Physics Front-End Electronics  

CERN Multimedia

The upgrade of the Large Hadron Collider (LHC) experiments at CERN sets new challenges for the powering of the detectors. One of the powering schemes under study is based on DC-DC buck converters mounted on the front-end modules. The hard environmental conditions impose strict restrictions to the converters in terms of low volume, radiation and magnetic field tolerance. Furthermore, the noise emission of the switching converters must not affect the performance of the powered systems. A study of the sources and paths of noise of a synchronous buck converter has been made for identifying the critical parameters to reduce their emissions. As proof of principle, a converter was designed following the PCB layout considerations proposed and then used for powering a silicon strip module prototype for the ATLAS upgrade, in order to evaluate their compatibility.

Fuentes, C; Michelis, S; Blanchot, G; Allongue, B; Faccio, F; Orlandi, S; Kayal, M; Pontt, J

2011-01-01

43

Current–Mode One-Cycle control applied to linear–assisted DC/DC converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article shows the proposal of an current-mode one-cycle control for linear-assisted DC/DC converters. Linear-assisted DC/DC converters are structures that allow to take advantages of the two classic alternatives in the design of power supply systems: voltage linear regulators (classic NPN topology or LDO –low dropout–) and switching DC/DC converters. The current-mode one-cycle control technique is proposed in order to obtain the duty cycle of the linear-assisted converter switch. The...

Marti?nez Garci?a, Herminio; Grau Saldes, Antoni; Bolea Monte, Yolanda; Ga?miz Caro, Juan

2011-01-01

44

Current-Mode One-Cycle Control Applied to Linear-Assisted DC/DC Converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article shows the proposal of an current-mode one-cycle control for linear-assisted DC/DC converters. Linearassisted DC/DC converters are structures that allow to take advantages of the two classic alternatives in the design of power supply systems: voltage linear regulators (classic NPN topology or LDO –low dropout–) and switching DC/DC converters. The current-mode one-cycle control technique is proposed in order to obtain the duty cycle of the linear-assisted converter switch. T...

Marti?nez Garci?a, Herminio; Grau Saldes, Antoni; Bolea Monte, Yolanda; Marti?nez Gonza?lez, Rube?n

2009-01-01

45

Current-mode one-cycle control applied to linear–assisted DC/DC converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article shows the proposal of an current-mode one-cycle control for linear-assisted DC/DC converters. Linear-assisted DC/DC converters are structures that allow to take advantages of the two classic alternatives in the design of power supply systems: voltage linear regulators (classic NPN topology or LDO –low dropout–) and switching DC/DC converters. The current-mode one-cycle control technique is proposed in order to obtain the duty cycle of the linear-assisted converter switch. The...

Marti?nez Garci?a, Herminio; Grau Saldes, Antoni; Bolea Monte, Yolanda; Ga?miz Caro, Juan

2011-01-01

46

Discontinuous Buck Converter  

Science.gov (United States)

This animation, created by faculty at Dartmouth University, is a discontinuous buck converter. The resource features other animations such as boost and discontinuous converters. They also add simple diode, bridge and half-wave rectifiers. Although simple in design, this can still be a useful resource for those interested in electrical engineering.

2009-11-19

47

Performance of a Voltage Step-Up/Step-Down Transformerless DC/DC Converter: Analytical Model  

Science.gov (United States)

The authors present an analytical model for a voltage step-up/step-down DC/DC converter without transformers. The proposed topology is a combination of classic buck and boost converters in one single circuit but with differing operational principles. The converter is developed for a wind power autonomous supply system equipped with a hydrogen electrolytic tank and a fuel cell for energy stabilization. The main power source of the hydrogen-based autonomous supply system is energized by a synchronous generator operating on permanent magnets and equipped with a diode bridge. The input voltage of the converter in this case varies in the range 0-700 V, while its output DC voltage must be 540 V according to the demand of other parts of the system. To maintain the rated voltage, a special electrical load regulation is introduced. The calculations of the converter, the generator (equipped with a diode bridge) as element of the power system supply joint, and the load replaced by resistance are verified with PSIM software.

Suskis, P.; Rankis, I.

2012-01-01

48

Optimization with System Damping Restoration for Droop Controlled DC-DC Converters  

DEFF Research Database (Denmark)

The parallel operation of dc-dc converters is widely used in distribution systems and uninterruptable power supply systems. Droop control along with virtual resistance (VR) is considered a simple and reliable method for achieving wireless power sharing among converters. In order to enhance the efficiency of the conversion system, this paper implements tertiary level optimization control on the basis of hierarchical control. As the efficiency of each converter changes with output power, VRs are set as decision variables for adjusting power sharing proportion among converters. Genetic algorithm is used in searching for global efficiency optimum. However system dynamic is affected when shifting VRs. Therefore, the stability of a parallel buck converter system is analyzed to examine the influence of VR changing on system dynamics. Based on the stability analysis, a system damping secondary restoration (SDSR) is implemented to readjust the optimization results so as to ensure system stability. Simulation results are shown to demonstrate the improvement of system efficiency and effectiveness of the method.

Meng, Lexuan; Dragicevic, Tomislav

2013-01-01

49

Modeling the Bi-directional DC-DC Converter for HEV's  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hybrid Electrical Vehicles-HEV!?s are the importnt ways to improve vehicle performance. The transformer isolated
bi-directional DC-DC converters are the key components of the traction system in HEV!?s. This paper presents adetail
mathematic model of isolated bi-directional DC-DC converter for HEV!?s. Approximate models are important
mathematic methods especially for analysis and closed-loop control design converter circuits.  These differential

Chongwu Wang; Xiangzhong Meng; Xiaowei Guo

2009-01-01

50

OPERATION OF PARALLELED DC-DC CONVERTERS TAKING INTO ACCOUNT CABLE RESISTANCES FOR LOAD SHARING APPLICATIONS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper two DC-DC converters connected in parallel with the purpose of load sharing by applying droop method is considered. This method requires no communication interconnection and compensates for converter parameter variations and imbalances in line impedance. The DC-DC converter input source can be any DC source such as photovoltaic module and wind turbine or fuel cell and it is a closed loop system. In this work proportional-integral (PI) controller, will have their performance eval...

2013-01-01

51

Design and Implementation of a FLC for DC-DC Converter in a Microcontroller for PV System  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the design and implementation of a simple fuzzy logic controller (FLC for a DC-DC buck converter based on the PIC18F4550 microcontroller to control the lead acid battery charging voltage in solar cells applications. For cost consideration, an inexpensive 8-bit microcontroller is selected to program and implement the FLC proportional-integral. The obtained simulation and experimental results show the viability of the controller with a variation on the load of the buck converter showing a good performance on the design of the FLC, and it has also a smooth response with a small overshoot. The DC-DC converter designed in this work can be found applications in low cost photovoltaic (PV systems, although in the literature has been already reported this kind of devices with a better response [3-4], however these use a expensive microcontroller or its designs are very complex, and where these are not necessary for this kind of applications. Finally, a prototype PV system with 100 V/6 A has been implemented for verifying the feasibility of the CD-CD converter.

Abel García-B.

2013-07-01

52

Control of the DC-DC Converter used into Energy Generation System  

International Nuclear Information System (INIS)

This paper presents an investigation of the DC-DC Converter controller used into Energy Generation System. The full bridge is used into an Energy Generation System (EGS) as second power interface between the energy source and the high DC bus. The simulation results show that the DC-DC Converter behavior can be improved using a well designed PI control surface. The used Simulink models for the EGS blocks and some design considerations are presented, too. (authors)

2006-10-25

53

A DC-DC Converter Efficiency Model for System Level Analysis in Ultra Low Power Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a model of inductor based DC-DC converters that can be used to study the impact of power management techniques such as dynamic voltage and frequency scaling (DVFS). System level power models of low power systems on chip (SoCs) and power management strategies cannot be correctly established without accounting for the associated overhead related to the DC-DC converters that provide regulated power to the system. The proposed model accurately predicts the efficiency of induct...

Aatmesh Shrivastava; Calhoun, Benton H.

2013-01-01

54

Non-Dissipative Snubber for Rectifying Diodes in a High-Power DC-DC Converter  

Science.gov (United States)

In a high output current DC-DC converter, most power dissipation comes from rectifying diodes. In this paper, a novel non-dissipative snubber is proposed for the rectifying diodes to reduce the power dissipation of the rectifying circuit. This snubber is applied to the center-tapped rectifying circuit in a full-bridge DC-DC converter. As a result, the efficiency has been improved to 91% on the prototype of 12V/80A output.

Hirokawa, Masahiko; Ninomiya, Tamotsu

55

A digitally controlled PWM/PSM dual-mode DC/DC converter  

International Nuclear Information System (INIS)

A digitally controlled pulse width modulation/pulse skip modulation (PWM/PSM) dual-mode buck DC/DC converter is proposed. Its operation mode can be automatically chosen as continuous conduction mode (CCM) or discontinuous conduction mode (DCM). The converter works in PSM at DCM and in 2 MHz PWM at CCM. Switching loss is reduced at a light load by skipping cycles. Thus high conversion efficiency is realized in a wide load current. The implementations of PWM control blocks, such as the ADC, the digital pulse width modulator (DPWM) and the loop compensator, and PSM control blocks are described in detail. The parameters of the loop compensator can be programmed for different external component values and switching frequencies, which is much more flexible than its analog rivals. The chip is manufactured in 0.13 ?m CMOS technology and the chip area is 1.21 mm2. Experimental results show that the conversion efficiency is high, being 90% at 200 mA and 67% at 20 mA. Meanwhile, the measured load step response shows that the proposed dual-mode converter has good stability. (semiconductor integrated circuits)

2011-11-01

56

Design of A Bidirectional Dc-Dc Converter For Hybrid Electric Vehicles (HEV Using MATLAB  

Directory of Open Access Journals (Sweden)

Full Text Available The design of a 60 kW bidirectional DC-DC converter is addressed in this paper. The paper also discusses the operation and role of dc-dc converter in Electric Vehicle (EV and Hybrid Electric Vehicle (HEV. Various circuits and their analysis are done to review the operation and design of converter. Results show that at 20Hz operation converter efficiency is better when ETD49 shape is used rather than EC70. However efficiencies are greater with ferrite materials rather than iron powder.

DHARAM DUTTA, SOUVIK GANGULI

2013-07-01

57

Design of the DC-DC power stage of the capacitor charger for MAXIDISCAP power converters  

CERN Document Server

This technical report presents the design of the DC-DC power stage of the capacitor charger for MAXIDISCAP power converters. The power stage is based on a half bridge series resonant converter in Discontinuous Conduction Mode (DCM). This simple and robust topology allows obtaining a current source behavior with a low switching losses power stage. The associated control stage is implemented using a commercial controller which has differenti nternal circuits that allows a high integration of the converter control system. The report presents the design and tuning criteria for the DC-DC converter, including the power stage and the control system.

Cravero, Jean-Marc

2013-01-01

58

Autonomous ultra-low power DC/DC converter for Microbial Fuel Cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, an ultra-low voltage and power DC/DC converter is presented. This converter harvests energy from a Microbial Fuel Cell (MFC) in order to feed another circuit such as an autonomous wireless sensor. The MFC behaves as a voltage generator of 475mV open-circuit voltage with a 600? serial internal impedance. The maximum delivered power is therefore around 100?W. The DC/DC converter provides output voltage in the range 2-7.5V and performs impedance matching with source. The convert...

Adami, Salah-eddine; Degrenne, Nicolas; Vollaire, Christian; Allard, Bruno; Buret, Franc?ois; Costa, Franc?ois

2011-01-01

59

Efficiency and Regulation of Commercial Low Power DC/DC Converter Modules at Low Temperatures  

Science.gov (United States)

DC/DC converters that are capable of operating at cryogenic temperatures are anticipated to play an important role in the power systems of future NASA deep space missions. Design of these converters to survive cryogenic temperatures will improve the power system performance, and reduce development and launch costs. At the NASA Glenn Research Center Low Temperature Electronics Laboratory, several commercial off-the-shelf dc/dc converter modules were evaluated for their low temperature performance. Various parameters were investigated as a function of temperature, in the range of 20 C to -190 C. Data pertaining to the efficiency and voltage regulation of the tested converters is presented and discussed.

Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

2000-01-01

60

DC-DC converters with reduced mass for trackers at the HL-LHC  

International Nuclear Information System (INIS)

The development at CERN of low noise DC-DC converters for the powering of front-end systems enables the implementation of efficient powering schemes for the physics experiments at the HL-LHC. Recent tests made on the ATLAS short strip tracker modules confirm the full electromagnetic compatibility of the DC-DC converter prototypes with front-end detectors. The integration of the converters in the trackers front-ends needs to address also the material budget constraints. The impact of the DC-DC converters onto the material budget of the ATLAS tracker modules is discussed and mass reduction techniques are explored, leading to a compromise between electromagnetic compatibility and mass. Low mass shield implementations and Aluminum core inductors are proposed. Also, the impact on emitted noise due to a size reduction of critical components is discussed. Finally, material reduction techniques are discussed at the board layout and manufacturing levels.

2011-11-01

 
 
 
 
61

Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper the SIMULINK model of a PWM controlled DC-DC converter is modeled using switching function concept to control the speed of the DC motor. The presence of the voltage oscillation cycles due to higher switching frequency in the DC-DC converter is identified. The effect of these oscillations on the output voltage of the converter, Armature current, Developed torque and Speed of the DC motor is analyzed. In order to minimize the oscillation cycles the PI controller is proposed in the...

Sreenivasappa Veeranna Bhupasandra; Udaykumar Yaragatti

2010-01-01

62

A Pedagogical Approach for Modeling and Simulation of Switching Mode DC-DC Converters for Power Electronics Course  

Directory of Open Access Journals (Sweden)

Full Text Available The power electronics course is a rather challenging subject for instructors and undergraduate students pursuing Bachelor’s Degree in Electrical Engineering. To enhance teaching effectiveness and motivate self-learning capabilities of the students, this paper presents a pedagogical approach for mathematical modeling and simulation of switching mode DC-DC converters. The Buck and Boost converters are analyzed as benchmark systems to study the power converter modeling methodologies. And a comparative analysis using digital simulation from Matlab/Simulink and ATP/EMTP is presented. A summary of student survey is also presented, which shows a high level of satisfaction. The presented pedagogical approach would be useful for classroom teaching for the power electronics course and similar engineering courses.

Han Yang

2012-10-01

63

Development of a fuzzy logic controller for dc/dc converters: Design, computer simulation, and experimental evaluation  

Energy Technology Data Exchange (ETDEWEB)

The design of a fuzzy logic controller for dc/dc converters is described in this paper. A brief review of fuzzy logic and its application to control is first given. Then, the derivation of a fuzzy control algorithm for regulating dc/dc converters is described in detail. The proposed fuzzy control is evaluated by computer simulations as well as experimental measurements of the closed-loop performance of simple dc/dc converters in respect of load regulation and line regulation.

So, W.C.; Tse, C.K.; Lee, Y.S. [Hong Kong Polytechnic Univ. (Hong Kong). Dept. of Electronic Engineering

1996-01-01

64

Neural-fuzzy control of DC-DC converters: An off-line learning approach  

Energy Technology Data Exchange (ETDEWEB)

Conventional linear frequency domain control methods fail to provide nonlinear control to cope with possible large variable fluctuation in DC-DC converters. Owing to the nonlinear behaviour, mainly provided by the fuzzy rules and membership functions of fuzzy logic, fuzzy logic control is a good alternative for controlling DC-DC converters. The problem of designing fuzzy logic controllers for DC-DC converters involves determining the fuzzy rules, the associated antecedent membership functions and consequent membership functions. This paper discusses the methodology of using neural networks to adjust the shapes and locations of the membership functions so that an optimal fuzzy control can be achieved. This method can eliminate the need for heavy computation in multi-variable control. (author). 10 figs., 12 refs.

So, W.C.; Tse, C.K. [Hong Kong Polytechnic, Kowloon (Hong Kong)

1995-12-31

65

High Current Planar Magnetics for High Efficiency Bidirectional DC-DC Converters for Fuel Cell Applications  

DEFF Research Database (Denmark)

Efficiency is one of the main concerns during the design phase of switch mode power supply. Planar magnetics based on PCB windings have the potential to reduce the magnetic manufacturing cost however, one of their main drawbacks comes from their low filling factor and high stray capacitance. This paper presents an analysis of different planar windings configurations focusing on dc and ac resistances in order to achieve highly efficiency in dc-dc converters. The analysis considers different copper thicknesses form 70 μm up to 1500 μm (extreme copper PCB) taking into account manufacturing complexity and challenges. The analysis is focused on a high current inductor for a dc-dc converter for fuel cell applications and it is based on FEM simulations. Analysis and results are verified on a 6 kW dc-dc isolated full bridge boost converter prototype based on fully planar magnetics achieving a peak efficiency of 97.8%.

Pittini, Riccardo; Zhang, Zhe

2014-01-01

66

Optimized photovoltaic generator-water electrolyser coupling through a controlled DC-DC converter  

Energy Technology Data Exchange (ETDEWEB)

The coupling of a photovoltaic generator and an electrolyser is one of the most promising options for obtaining hydrogen from a renewable energy source. Both are well known technologies, however, since the high variability of the solar radiation, an efficient coupling still presents some challenges. Direct or through a DC-DC converter couplings are the options in isolated applications. In this work, three models, respectively, for a photovoltaic (PV) generator, a controlled DC-DC converter and a complete proton exchange membrane (PEM) electrolyser have been designed by using Matlab/Simulink. A PV-electrolyser specific algorithm to search for the optimum and safe working point for both elements is presented. Simulation results demonstrate that the use of a controlled DC-DC converter with the proposed algorithm shows better adaptability to the variable radiation conditions than the other coupling options. Therefore, it leads to a better compliance between the electrolyser and the sizing of the PV generator. (author)

Garcia-Valverde, R.; Miguel, C.; Urbina, A. [Universidad Politecnica de Cartagena, Departamento de Electronica, Tecnologia de Computadoras y Proyectos, Plaza del Hospital, 1, Cartagena, 30203 Murcia (Spain); Martinez-Bejar, R. [Universidad de Murcia, Departamento de Ingenieria de la Informacion y las Comunicaciones, Facultad de Informatica, Campus de Espinardo, 30071 Murcia (Spain)

2008-10-15

67

Modelling, Simulation and Construction of a DC/DC Boost Power Converter: A School Experimental System  

Science.gov (United States)

We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders…

Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

2012-01-01

68

Soft switching bidirectional DC-DC converter for ultracapacitor-batteries interface  

International Nuclear Information System (INIS)

In this paper a new soft switching bidirectional DC-DC converter is introduced which can be applied as the interface circuit between ultracapacitors and batteries or fuel cells. All semiconductor devices in the proposed converter are soft switched while the control circuit remains PWM. Due to achieved soft switching condition, the energy conversion through the proposed converter is highly efficient. The proposed converter is analyzed and a prototype converter is implemented. The presented experimental results confirm the theoretical analysis.

2009-12-01

69

Soft switching bidirectional DC-DC converter for ultracapacitor-batteries interface  

Energy Technology Data Exchange (ETDEWEB)

In this paper a new soft switching bidirectional DC-DC converter is introduced which can be applied as the interface circuit between ultracapacitors and batteries or fuel cells. All semiconductor devices in the proposed converter are soft switched while the control circuit remains PWM. Due to achieved soft switching condition, the energy conversion through the proposed converter is highly efficient. The proposed converter is analyzed and a prototype converter is implemented. The presented experimental results confirm the theoretical analysis. (author)

Adib, Ehsan; Farzanehfard, Hosein [Dept. of Electrical and Computer Engineering, Isfahan Univ. of Technology (Iran)

2009-12-15

70

Half bridge ZVS DC-DC converter with DCS PWM active clamp technique  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Half bridge (HB) dc–dc converter is an attractive topology for middle power level applications owing to its simplicity. This paper presents a new control scheme, to be known as duty-cycle shifted PWM (DCS PWM) control, is proposed and applied to the conventional HB dc–dc converters to achieve ZVS for one of the two switches without adding extra components and without adding asymmetric penalties of the complementary control. The concept of this new control scheme is shifting one o...

JANAPATI SIVAVARA PRASAD

2012-01-01

71

Using Nyquist or Nyquist-Like Plot to Predict Three Typical Instabilities in DC-DC Converters  

CERN Multimedia

By transforming an exact stability condition, a new Nyquist-like plot is proposed to predict occurrences of three typical instabilities in DC-DC converters. The three instabilities are saddle-node bifurcation (coexistence of multiple solutions), period-doubling bifurcation (subharmonic oscillation), and Neimark bifurcation (quasi-periodic oscillation). In a single plot, it accurately predicts whether an instability occurs and what type the instability is. The plot is equivalent to the Nyquist plot, and it is a useful design tool to avoid these instabilities. Nine examples are used to illustrate the accuracy of this new plot to predict instabilities in the buck or boost converter with fixed or variable switching frequency.

Fang, Chung-Chieh

2012-01-01

72

Synchronized Pulsed dc - dc Converter as Maximum Power Position Tracker with Wide Load and Insolation Variation for Stand Alone PV System  

International Nuclear Information System (INIS)

This paper investigates the interest focused on employing parallel connected dc-dc converter with high tracking effectiveness under wide variation in environmental conditions (Insolation) and wide load variation. dc-dc converter is an essential part of the stand alone PV system. Paper also presents an approach on how duty cycle for maximum power position (MPP) is adjusted by taking care of varying load conditions and without iterative steps. Synchronized PWM pulses are employed for the converter. High tracking efficiency is achieved with continuous input and inductor current. In this approach, the converter can he utilized in buck as well in boost mode. The PV system simulation was verified and experimental results were in agreement to the presented scheme. (authors)

2011-01-01

73

DC/DC converters for integration of double-layer condensers in onboard power supply; DC/DC-Wandler zur Einbindung von Doppelschichtkondensatoren in das Fahrzeugenergiebordnetz  

Energy Technology Data Exchange (ETDEWEB)

The paper discusses DC/DC converters for integration of double layer condensers into the onboard power system. First, requirements on DC/DC converters are listed and compared on the basis of three exemplary applications. A DC/DC converter concept is developed for decoupling transient high-power loads like electric steering systems. Three different topologies are compared using a specially developed method in order to find the best solution for the given application. In order to establish adequate criteria for selecting the switching frequency and inductivities of storage throttles, the influence of the trottle power change on the switching characteristics of the MOSFETs and on certain ranges of EMP interference emissions is investigated. As methods of optimising the operation of the synchronous rectifiers, parallel connection of Schottky diodes and synchronous rectifiers as well as the variation of the shut-off dead times of synchronous rectifiers were investigated. Further, a concept for converter control was developed in consideration of the intended application and topology. Finally, selected aspects for implementation of the DC/DC converter concept are presented as well as the results of experimental investigations.

Polenov, Dieter

2010-01-15

74

ZVZCS PWM DC-DC Converter with Energy Recovery Clamp  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents research motivated by industrial demand for special traction drive topology devoted tominimization of traction transformer weight against topology with classical 50Hz traction transformer. The special tractiondrive topology for AC power systems consists of input high voltage trolley converter (single phase matrix converter) –middle frequency transformer – output converter - traction motor has been described. The main attention has been given tothe control algorithm of ...

Jaroslav Durdik; Vladimir Ruscin

2008-01-01

75

Symmetrical multilevel converters with two quadrant DC-DC feeding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the technology sector of power electronics and control, the multilevel converter technology is still a rather new research area, but the application possibilities in the field of power drives and energy will demand more solutions with this promising technology. In the future, more converter systems will be realized with the multilevel topology. Up to now, multilevel converters have only been used in very particular applications, mainly due to the high costs and complexity of the multilevel...

Schibli, Nikolaus

2000-01-01

76

Soft Switched Multi-Output PWM DC-DC Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, a new soft switched cell that overcomes most of the drawbacks of the normal "hard switched-pulse width modulation" converter is proposed to contrive a new family of soft switched PWM converters. All of the semiconductor devices in this converter are turned on and off under exact or near zero voltage switching (ZVS) and/or zero current switching (ZCS). No additional voltage and current stresses on the main switch and main diode occur. A push-pull converter equipped with the prop...

Rashmi Sharma

2013-01-01

77

A high voltage ratio and low ripple interleaved DC-DC converter for fuel cell applications.  

Science.gov (United States)

This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters. PMID:23365536

Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

2012-01-01

78

A Novel PPFHB Bidirectional DC-DC Converter for Supercapacitor Application  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a novel bidirectional DC-DC converter for the supercapacitor application. In the proposed converter, push-pull forward with half bridge (PPFHB) voltage doubler structure is used to reduce the number of the power switches and get higher voltage gain. Based on phase-shift modulation scheme, all the switches can realize zero-voltageswitching (ZVS) turn-on and bidirectional power flow can be controlled with phase-shift angle. The operating principles of the converter are descr...

Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael Andreas E.

2009-01-01

79

Bifurcation and Chaos in a Pulse Width modulation controlled Buck Converter  

DEFF Research Database (Denmark)

Power electronic system with pulse width modulation (PWM) control is studied. Behaviour characteristic for a nonlinear dynamical system is observed and theoretically explained. A DC-DC buck converter controlled by a voltage feedback is taken as an example. The studied system is described by a system of piecewise-smooth nonautonomous differential equations. The research are focused on chaotic oscillations analysis and analytical search for bifurcations dependent on parameter. The most frequent route to chaos by the period doubling is observed in the second order DC-DC buck converter. Other bifurcations as a complex behaviour in power electronic system evidence are also described. In order to verify theoretical study the experimental DC-DC buck converter was build. The results obtained from three sources were presented and compared. A very good agreement between theory and experiment was observed.

Kocewiak, Lukasz; Bak, Claus Leth

2007-01-01

80

Pulse-width modulated DC-DC power converters  

CERN Document Server

This book studies switch-mode power supplies (SMPS) in great detail. This type of converter changes an unregulated DC voltage into a high-frequency pulse-width modulated (PWM) voltage controlled by varying the duty cycle, then changes the PWM AC voltage to a regulated DC voltage at a high efficiency by rectification and filtering. Used to supply electronic circuits, this converter saves energy and space in the overall system. With concept-orientated explanations, this book offers state-of-the-art SMPS technology and promotes an understanding of the principle operations of PWM converters,

Kazimierczuk, Marian K

2008-01-01

 
 
 
 
81

Improvement of burst-mode control of piezoelectric transformer based DC/DC converter  

International Nuclear Information System (INIS)

Burst-mode operation is adopted sometimes in piezoelectric transformer based converters for two major purposes: (1) to achieve voltage regulation in DC/DC converters and (2) to achieve dimming control in backlight inverters. Burst-mode control enables the converter to operate at a constant switching frequency as well as to maintain good efficiency at light load conditions. However, in practice, the piezoelectric transformer cannot instantly stop vibrating in the burst-mode due to its high quality factor. The delay in the output voltage change resulting from this behavior influences the accuracy of the regulation. This paper proposes a control strategy to make the piezoelectric transformer stop more quickly so as to enhance the accuracy of burst-mode control. The proposed method only modifies the control signal of the burst-mode driving circuit. The proposed control strategy is verified by experiments in a step-down 9 W DC/DC converter. (paper)

2013-05-01

82

A suitable model plant for control of the set fuel cell-DC/DC converter  

Energy Technology Data Exchange (ETDEWEB)

In this work a state and transfer function model of the set made up of a proton exchange membrane (PEM) fuel cell and a DC/DC converter is developed. The set is modelled as a plant controlled by the converter duty cycle. In addition to allow setting the plant operating point at any point of its characteristic curve (two interesting points are maximum efficiency and maximum power points), this approach also allows the connection of the fuel cell to other energy generation and storage devices, given that, as they all usually share a single DC bus, a thorough control of the interconnected devices is required. First, the state and transfer function models of the fuel cell and the converter are obtained. Then, both models are related in order to achieve the fuel cell+DC/DC converter set (plant) model. The results of the theoretical developments are validated by simulation on a real fuel cell model. (author)

Andujar, J.M.; Segura, F.; Vasallo, M.J. [Departamento de Ingenieria Electronica, Sistemas Informaticos y Automatica, E.P.S. La Rabida, Universidad de Huelva, Ctra. Huelva - Palos de la Frontera, S/N, 21819 La Rabida - Palos de la Frontera Huelva (Spain)

2008-04-15

83

Cryogenic Evaluation of an Advanced DC/DC Converter Module for Deep Space Applications  

Science.gov (United States)

DC/DC converters are widely used in power management, conditioning, and control of space power systems. Deep space applications require electronics that withstand cryogenic temperature and meet a stringent radiation tolerance. In this work, the performance of an advanced, radiation-hardened (rad-hard) commercial DC/DC converter module was investigated at cryogenic temperatures. The converter was investigated in terms of its steady state and dynamic operations. The output voltage regulation, efficiency, terminal current ripple characteristics, and output voltage response to load changes were determined in the temperature range of 20 to -140 C. These parameters were obtained at various load levels and at different input voltages. The experimental procedures along with the results obtained on the investigated converter are presented and discussed.

Elbuluk, Malik E.; Hammoud, Ahmad; Gerber, Scott S.; Patterson, Richard

2003-01-01

84

Optimization of the design of DC-DC converters for improving the electromagnetic compatibility with the Front-End electronic for the super Large Hadron Collider Trackers  

CERN Multimedia

The upgrade of the Large Hadron Collider (LHC) experiments at CERN sets new challenges for the powering of the detectors. One of the powering schemes under study is based on DC-DC buck converters mounted on the front-end modules. The hard environmental conditions impose strict restrictions to the converters in terms of low volume, radiation and magnetic field tolerance. Furthermore, the noise emission of the switching converters must not affect the performance of the powered systems. A study of the sources and paths of noise of a synchronous buck converter has been made for identifying the critical parameters to reduce their emissions. As proof of principle, a converter was designed following the PCB layout considerations proposed and then used for powering a silicon strip module prototype for the ATLAS upgrade, in order to evaluate their compatibility.

Fuentes Rojas, Cristian Alejandro; Blanchot, G

2011-01-01

85

Predictive Trailing-Edge Modulation Average Current Control in DC-DC Converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper investigates predictive digital average current control (PDACC) in dc/dc converters using trailing-edge modulation (TEM). The study is focused on the recurrence duty cycle equation and then stability analysis is performed. It is demonstrated that average current control using trailing-edge modulation is stable on the whole range of the duty cycle and thus design problems are highly reduced. The analysis is carried out in a general manner, independent of converter topology and th...

Draghici, D.; Lascu, D.

2013-01-01

86

A Three-Phase Bidirectional DC-DC Converter for Automotive Applications  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a three-phase soft-switching, bidirectional dc-dc converter for high-power automotive applications. The converter employs dual three-phase active bridges and operates with a novel asymmetrical but fixed duty cycle for the top and bottom switches of each phase leg. Simulation and experimental data on a 6-kW prototype are included to verify the novel operating and power flow control principles.

Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

2008-01-01

87

High-Temperature SOI/SiC-Based DC-DC Converter Suite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A complete design strategy (mechanical and electrical) for a 25 W 28 V/5 V dc-dc converter utilizing SiC and SOI electronics is presented. The converter includes a high-temperature SOI-based PWM controller featuring 150 kHz operation, a PID feedback loop, maximum duty cycle limit, complementary or symmetrical outputs, and a bootstrapped high-side gate driver. Several...

Reese, Bradley A.; Brice McPherson; Robert Shaw; Jared Hornberger; Schupbach, Roberto M.; Lostetter, Alexander B.

2008-01-01

88

Current-Steering Switching Policy for a SIDO Linear-Assisted Hysteretic DC/DC Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes the use of linear-assisted switching power converters in the context of single-inductor dual-output (SIDO) applications. By combining a DC/DC ripplecontrolled switching power converter with the respective voltage linear regulators at each output, improved performance in terms of load and line regulations is obtained. To achieve that aim, a current-steering switching policy is proposed, together with a resource-aware circuit implementation. The ripple-based hysteretic...

Marti?nez Garci?a, Herminio; Silva-marti?nez, Jose?; Alarco?n Cot, Eduardo Jose?; Poveda Lo?pez, Alberto

2010-01-01

89

LPV model for PV cell and fractional control of DC/DC converter for photovoltaic systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper deals with the fractional modelling of a DC-DC converter, suitable in solar-powered electrical generation systems, and the design of a fractional controller for the aforementioned switching converter. A new model for PV cells is proposed in order to obtain a linear equation for V-I characteristic via scheduling dependence of temperature and irradiance. Due to the fractional nature of the ultracapacitors this kind of controller gives a suitable and good performance.

Marti?nez Gonza?lez, Rube?n; Bolea Monte, Yolanda; Grau Saldes, Antoni; Marti?nez Garci?a, Herminio

2011-01-01

90

5 kW DC/DC converter for hydrogen generation from photovoltaic sources  

Energy Technology Data Exchange (ETDEWEB)

This paper covers the design of a DC-DC power converter aimed for hydrogen production from photovoltaic sources. Power conditioning for such application is usually driven by different constraints: high step-down conversion ratio is required if the input voltage of such equipment has to be compatible with photovoltaic sources that are connected to grid-connected inverters; galvanic isolation; high efficiency and low mass. Taking into account those factors, this work proposes a push-pull DC/DC converter for power levels up to 5 kW. The operation and features of the converter are presented and analyzed. Design guidelines are suggested and experimental validation is also given. (author)

Garrigos, A.; Blanes, J.M.; Carrasco, J.A.; Lizan, J.L. [Area de Tecnologia Electronica, Universidad Miguel Hernandez de Elche, Avda. de la Universidad s/n, 03202 Elche, Alicante (Spain); Beneito, R. [AIJU, Avda. de la Industria 23, 03440 Ibi, Alicante (Spain); Molina, J.A. [Grupo SITEC, Calle Cadiz 38, Poligono Industrial L' Alfac III, 03440 Ibi, Alicante (Spain)

2010-06-15

91

Voltage Tracking of a DC-DC Flyback Converter Using Neural Network Control  

Directory of Open Access Journals (Sweden)

Full Text Available This paper proposes a neural network control scheme of a DC-DC Flyback converter that will step up a 12V DC and applied it on brushless DC motor with 12 and 24V dc. In this technique, a back propagation learning algorithm is derived. The controller is designed to track the output voltage of the DC-DC converter and to improve performance of the Flyback converter during transient operations. Furthermore, to investigate the effectiveness of the proposed controller, some operations such as starting-up and reference voltage variations are verified. The numerical simulation results show that the proposed controller has a better performance compare to the conventional PI-Controller method.

Md Zarafi Ahmad

2012-01-01

92

Modeling the Bi-directional DC-DC Converter for HEV's  

Directory of Open Access Journals (Sweden)

Full Text Available Hybrid Electrical Vehicles-HEV!?s are the importnt ways to improve vehicle performance. The transformer isolated bi-directional DC-DC converters are the key components of the traction system in HEV!?s. This paper presents adetail mathematic model of isolated bi-directional DC-DC converter for HEV!?s. Approximate models are important mathematic methods especially for analysis and closed-loop control design converter circuits.  These differential equations, which govern the converter operation, change periodically among a set of linear differential equations because of the switch effect. Basing on the time-scale the state variables was separate as fast-scale and slow-scale variables. The fast changing variable of the leakage inductor was eliminated by substitute the fast-scale variable into slow-scale variable equations, resulting in reduced order differential equations. From this set of  reduced orderdifferential equations the completely averaged model of the isolated DC/DC converter was derived. The simulated results reveal that the circuit and mathematical model are consistent very well. The averaged state variables can be treated as a small component plus a DC component, so the averaged model can be separated a dynamic small signal part and a DC part. This linearized small signal model is suit for control design and analysis at a steady point that is decided by the DC component. As an example a PI controller was design basing on the linear model.

Chongwu Wang

2009-02-01

93

A DC-DC Converter Efficiency Model for System Level Analysis in Ultra Low Power Applications  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a model of inductor based DC-DC converters that can be used to study the impact of power management techniques such as dynamic voltage and frequency scaling (DVFS. System level power models of low power systems on chip (SoCs and power management strategies cannot be correctly established without accounting for the associated overhead related to the DC-DC converters that provide regulated power to the system. The proposed model accurately predicts the efficiency of inductor based DC-DC converters with varying topologies and control schemes across a range of output voltage and current loads. It also accounts for the energy and timing overhead associated with the change in the operating condition of the regulator. Since modern SoCs employ power management techniques that vary the voltage and current loads seen by the converter, accurate modeling of the impact on the converter efficiency becomes critical. We use this model to compute the overall cost of two power distribution strategies for a SoC with multiple voltage islands. The proposed model helps us to obtain the energy benefits of a power management technique and can also be used as a basis for comparison between power management techniques or as a tool for design space exploration early in a SoC design cycle.

Benton H. Calhoun

2013-06-01

94

A High Power Density DC-DC Converter for Distributed PV Architectures  

Energy Technology Data Exchange (ETDEWEB)

In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

Agamy, Mohammed S; Chi, Song; Elasser, Ahmed; Harfman-Todorovic, Maja; Jiang, Yan; Mueller, Frank; Tao, Fengfeng

2012-06-01

95

A High Voltage Ratio and Low Ripple Interleaved DC-DC Converter for Fuel Cell Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM s...

Chang, Long-yi; Chao, Kuei-hsiang; Chang, Tsang-chih

2012-01-01

96

DC-DC Converter Topology Assessment for Large Scale Distributed Photovoltaic Plant Architectures  

Energy Technology Data Exchange (ETDEWEB)

Distributed photovoltaic (PV) plant architectures are emerging as a replacement for the classical central inverter based systems. However, power converters of smaller ratings may have a negative impact on system efficiency, reliability and cost. Therefore, it is necessary to design converters with very high efficiency and simpler topologies in order not to offset the benefits gained by using distributed PV systems. In this paper an evaluation of the selection criteria for dc-dc converters for distributed PV systems is performed; this evaluation includes efficiency, simplicity of design, reliability and cost. Based on this evaluation, recommendations can be made as to which class of converters is best fit for this application.

Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Sabate, Juan A; Steigerwald, Robert L; Jiang, Yan; Essakiappan, Somasundaram

2011-07-01

97

Very High Frequency Resonant DC/DC Converters for LED Lighting  

DEFF Research Database (Denmark)

This paper presents a very high frequency DC/DC converter for LED lighting. Several resonant topologies are compared and their usability discussed. At the end the resonant SEPIC converter is chosen based on the achievable power density and total bill of material. Simulations of a 51 MHz converter with 40 V input and 15 V output are made. The simulation shows possibility of achieving efficiency up to 87 % even with a HEXFET Power MOSFET. Three prototypes of the simulated converter are implemented showing good correlation with simulations. The prototypes have efficiencies up to 84 % and power densities up to 8.9 W/cm3 (146 W/in3).

Madsen, Mickey Pierre; Knott, Arnold

2013-01-01

98

Switched capacitor DC-DC converter ASICs for the upgraded LHC trackers  

Energy Technology Data Exchange (ETDEWEB)

The High Luminosity Upgrade of the ATLAS Inner Tracker puts demanding requirements on the powering system of the silicon strip detector modules due to 10-fold increase of the channel count compared to the existing SemiConductor Tracker. Therefore, new solutions for the powering scheme must be elaborated. Currently two possible approaches, the serial powering and the parallel powering scheme using the DC-DC conversion technique, are under development. This paper describes two switched capacitor DC-DC converters designed in a 130 nm technology. For the optimized step-down converter, foreseen for the parallel powering scheme, power efficiency of 97% has been achieved, while for the charge pump, designed for the serial powering scheme, power efficiency of 85% has been achieved.

Bochenek, M; Faccio, F; Michelis, S [CERN, CH-1211 Geneve 23 (Switzerland); Dabrowski, W, E-mail: Michal.Bochenek@cern.ch [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. Mickiewicza 30 30-059 Krakow (Poland)

2010-12-15

99

A Nonlinear Digital Control Solution for a DC/DC Power Converter  

Science.gov (United States)

A digital Nonlinear Proportional-Integral-Derivative (NPID) control algorithm was proposed to control a 1-kW, PWM, DC/DC, switching power converter. The NPID methodology is introduced and a practical hardware control solution is obtained. The design of the controller was completed using Matlab (trademark) Simulink, while the hardware-in-the-loop testing was performed using both the dSPACE (trademark) rapid prototyping system, and a stand-alone Texas Instruments (trademark) Digital Signal Processor (DSP)-based system. The final Nonlinear digital control algorithm was implemented and tested using the ED408043-1 Westinghouse DC-DC switching power converter. The NPID test results are discussed and compared to the results of a standard Proportional-Integral (PI) controller.

Zhu, Minshao

2002-01-01

100

Current-sourced buck converter  

Energy Technology Data Exchange (ETDEWEB)

Solar and magnetic energy harvesting may benefit from the use of current-sourced converters for interfacing those sources into the practical usage due to their current-source nature. The paper investigates the implementation and dynamics of such converters by means of a current-sourced buck converter. Duality concepts are applied to obtain the converter from the corresponding voltage-sourced buck converter. The dynamic analysis is carried out in continuous capacitor-voltagemode under direct-duty-ratio control. The theoretical findings are verified by extracting the transfer functions from the Matlab-Simulink-based switching models. (orig.)

Leppaeaho, J.; Karppanen, M. (Electrical Energy Engineering Department, Tampere University of Technology (Finland)); Suntio, T. (Electrical Engineering Department, Tampere University of Technology (Finland))

2008-07-01

 
 
 
 
101

On the Robust Control of DC-DC Converters: Application to a Hybrid Power Generation System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper a complete robust control synthesis is performed for a hybrid power generation structure composed by a Fuel Cell and a Supercapacitor. The control strategies are applied to the DC-DC boost power converters associated to each power source. Multivariable PI control with H? performance, H? full and reduced order controllers are designed and compared. The multivariable PI controller is designed through an optimization procedure based on solving some Linear Matrix Inequalities. A...

Hernandez-torres, David; Sename, Olivier; Riu, Delphine; Druart, Florence

2010-01-01

102

Boundary Conditions of Subharmonic Oscillations in Fixed-Switching-Frequency DC-DC Converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Design-oriented boundary conditions for subharmonic oscillations are of great interest recently. Based on a subharmonic oscillation boundary condition reported in a PhD thesis more than a decade ago, extended new boundary conditions are derived in closed forms for general switching DC-DC converters. Sampled-data and harmonic balance analyses are applied and generate equivalent results. It is shown that equivalent series resistance causes the boundary conditions for voltage/c...

Fang, Chung-chieh

2012-01-01

103

An adaptive digital controller for satellite medium power DC/DC converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper the work concerning an adaptive digital controller for satellite medium power DC/DC converters is presented. The adaptive techniques and methods developed in Space Research Centre allows an implemented in VHDL controller to modify its parameters according to detected changes in operating conditions. Inductor entering from discontinuous to continuous current mode and vice versa or moving sampling instants due to changes in duty time are good examples of varying operation...

Skup, Konrad R.; Grudzi Ski, Pawe; Orlea Ski, Orlea Ski

2011-01-01

104

Inductor based switching DC-DC converter for low voltage power distribution in SLHC  

CERN Multimedia

In view of a power distribution scheme compatible with the requirements of the SLHC environment, we are evaluating the feasibility of on-board inductor-based DC-DC step-down conversion. Such converter should be an integrated circuit and capable of operating in harsh radiation environments and in the high magnetic field of the experiments. In this paper we present results concerning the choice of the technology, the search for the magnetic components and the calculations of the expected efficiency.

Michelis, S; Marchioro, A; Kayal, M; PH-EP

2007-01-01

105

Simulation Based Performance analysis of Active Clamp DHB ZVZCS Bidirectional DC-DC converter for Low Power Applications  

Directory of Open Access Journals (Sweden)

Full Text Available A novel active clamp dual half bridge DC/DC converter with bidirectional power flow is proposed in this paper and comparative analysis between active clamp DHB ZVZCS and ZVS-ZCS bidirectional DC-DC converter topologies is also presented. By adding active clamping circuits to both bridges, zero voltage and zero current switching are achieved to improve the performance of the bidirectional DC/DC converter. The principle of operation is analyzed and simulated. With the proposed active clamp ZVZCS concept, the MATLAB simulation results of the applications of the fuel cell and battery have been obtained and compared with those of ZVS-ZCS bidirectional converter. The simulation results of proposed converter is compared with the ZVS-ZCS bidirectional DC-DC converter, efficiency, switching losses are the key parameters compared.

V.V.Subrahmanya Kumar Bhajana

2012-06-01

106

Immediate Analysis of Periodic Steady States in Switched DC-DC Converters via SPICE  

Directory of Open Access Journals (Sweden)

Full Text Available The method of immediate analysis of periodic steady states in switched DC-DC converters operating in the continuous current mode is described. The initial conditions, which correspond to the periodic steady state, are found in the first step. They are used consequently for the conventional transient analysis. A special SPICE model of the converter finds automatically these initial conditions, which are then available within the transient analysis. The method works both for the well-known behavioral models of switched converters and also for models which employ complex nonlinear SPICE models of semiconductor switches.

D. Biolek

2012-04-01

107

Novel technique for bidirectional series-resonant DC/DC converter in discontinuous mode  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study analyses a novel technique for obtaining a voltage conversion ratio greater than one in a bidirectional series-resonant DC/DC converter (SRC). The converter works in a discontinuous mode: it transfers energy in packets, but it also accumulates some packets in order to raise the output voltage. This study presents a comprehensive theoretical analysis for the two modes: the step-down mode (common mode) and the novel step-up mode. The converter transfers energy during fixed time inter...

Ibanez, Federico; Martin Echeverria, Jose; Fontan, Luis

2013-01-01

108

Modeling and Current Programmed Control of a Bidirectional Full Bridge DC-DC Converter  

Directory of Open Access Journals (Sweden)

Full Text Available Modelling of bidirectional full bridge DC-DC converter as one of the most applicable converters has received significant attention. Mathematical modelling reduces the simulation time in comparison with detailed circuit response; moreover it is convenient for controller design purpose. Due to simple and effective methodology, average state space is the most common method among the modelling methods. In this paper a bidirectional full bridge converter is modelled by average state space and for each mode of operations a controller is designed. Attained mathematical model results are in a close agreement with detailed circuit simulation.

Abdolreza Rahmati

2012-05-01

109

Buck-Converter Photovoltaic Simulator  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a Photovoltaic Simulator Simulation using Buck Converter with analysis using bode diagram. A state space simulator model is derived to provide a detail non-linear model. The PV Static Model is modified by adding a low pass filter in order to avoid an algebraic loop problem and able to analyze easier. PV simulator is realized by controlling buck converter’s current using PI Controller with reference from PV model. Then the model is linearized which is used for a...

Feri Yusivar; Farabi, M. Y.; Suryadiningrat, R.; Ananduta, W. W.; Syaifudin, Y.

2011-01-01

110

SOFT-SWITCHED HIGH STEP-UP DC-DC CONVERTER WITH HIGH VOLTAGE GAIN  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a new design of soft switched high step-up dc-dc converter with high voltage gain which is suitable for high power applications such as Uninterruptible Power System (UPS, Photo Voltaic system and hybrid electric vehicles. The emergence of this front-end converter is to improve the shape of active input current given to the system. This converter proposes Soft-Switching technique to achieve ZVS turn on of active switches and ZCS turn off of diodes using Lr - Cr resonance in the auxiliary circuit. Therefore reduces the switching losses. Comparatively the voltage conversion ratio of this converter is higher when compared with the ordinary boost converter. Hence the voltage gain of this converter is also higher. A simulation platform is created using MATLAB which illustrates the ZVS and ZCS operation of the switches and diodes. Open loop and closed loop controlled converter systems are modelled and simulated.

J.C. PAUL IMMANUEL

2013-04-01

111

Programmed pulsewidth modulated waveforms for electromagnetic interference mitigation in dc-dc converters  

Energy Technology Data Exchange (ETDEWEB)

The regular switching action of a pulsewidth modulated (PWM) circuit generates conducted and radiated electro-magnetic interference (EMI), and may also generate acoustical disturbances. Programmed pulsewidth modulation techniques have been applied suing various methods to control harmonics inherent in switched power circuits. In this paper, a method to generate an optimal programmed switching waveform for a dc-dc converter is presented. This switching waveform is optimized to reduce the amplitude of harmonic peaks in the EMI generated by the converter. Experimental results, a brief discussion of sensitivity, and a practical implementation of a circuit to generate the PWM waveform are given.

Wang, A.C.; Sanders, S.R. [Univ. of California, Berkeley, CA (United States). Dept. of Electrical Engineering and Computer Science

1993-10-01

112

Fast control technique for high frequency DC/DC integrated converter based on non-invasive output capacitance current estimation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

High switching frequency allows the integration of low power DC/DC converters. Although a high switching frequency would make feasible a voltage mode control with 1MHz bandwidth, parasitic effects and robustness don’t allow such a high bandwidth. This paper proposes a fast control to optimize the dynamic response of high frequency DC/DC converters. The proposed control is based on the peak current mode control of the output capacitor current. The output capacitor current loop provid...

Viejo Frutos, Miriam Del; Alou Cervera, Pedro; Oliver Rami?rez, Jesu?s Angel; Garci?a Sua?rez, Oscar; Cobos Ma?rquez, Jose? Antonio

2010-01-01

113

A DC-DC Conversion Powering Scheme for the CMS Phase-1 Pixel Upgrade  

CERN Document Server

The powering scheme of the CMS pixel detector will be described, and the performance of prototype DC-DC buck converters will be presented, including power efficiency, system tests with DC-DC converters and pixel modules, thermal management, reliability at low temperature, and studies of potential frequency locking betwe...

Feld, Lutz Werner; Marcel Friedrichs; Richard Hensch; Karpinski, Waclaw; Klein, Katja; Sammet, Jan Domenik; Wlochal, Michael

2012-01-01

114

Multi-Level DC-DC Converter for High Gain Applications  

Directory of Open Access Journals (Sweden)

Full Text Available The output voltage from most renewable energy sources like photovoltaic arrays and fuel cells will be at low level. This must be stepped up considerably for practical utilization or grid connection. The presented multilevel boost converter DC-DC converter topology consists of the conventional boost converter and voltage doubler stages to provide high voltage gain. The proposed topology uses only one switch along with one inductor, (2N-1 diodes and (2N-1 capacitors for obtaining an output which is N times the conventional boost converter. In this topology, each device blocks only one voltage level. The main advantages of this topology are continuous input current, large gain without high duty cycle or transformer, modularity and use of devices with low voltage ratings. Experimental results obtained from the 100W prototype demonstrate the voltage gain capability of the converter and validates the converter design.

Girish Ganesan R

2013-12-01

115

MPP-Tracking DC-DC converters in Photovoltaic applications. Implementation, modeling and analysis  

Energy Technology Data Exchange (ETDEWEB)

This thesis provides a comprehensive study of switched-mode dc-dc converters in terms of dynamic characterization, implementation and operational constraints. The study concentrates on the maximum-power-point-tracking converters used in photovoltaic interfacing in order to maximize the power generation. The main objective is to emphasize the differences between the four basic conversion schemes and to analyze the dynamical characteristics of the current-fed converters. Harvesting of solar energy directly into electrical energy is known to be challenging due to the highly varying terminal characteristics of the energy harvesting unit, i.e., generally a photovoltaic generator. The environmental conditions as well as the load determine its characteristics. The operation point of PV generator has to be kept at its maximum-power point in order to maximize the harvested energy. The dc-dc switched-mode converters are conventionally used to interface the energy sources possessing constant-voltage behavior such as batteries or voltage buses but the same converters are also used as a basis for the maximum-power-point-tracking devices. It is observed, however, that such voltage-fed converters are not capable of interfacing a photovoltaic generator optimally because of its current-source nature. Therefore, an additional capacitor is usually added between the source and converter to enhance the constant-voltage properties of the source and to enable the input-voltage-based feedback control. It is known that the dual nature of PV generator enables the use of either input-voltage or input-current feedback control. It is observed, that the input-current control is prone to saturation of the controller and therefore, the input-voltage control is recommended to be used. The use of input-voltage control will, however, force the converter operate as a current-fed converter causing also significant changes to its static and dynamic properties as well as constraints related to the voltage-fed converters in photovoltaic interfacing. This thesis presents the generalized dynamic representation of a switched-mode dc-dc converter which can be applied to analyze all possible conversion schemes. The representation makes a clear distinction between the voltage-fed and current-fed conversion schemes and their stability assessment. It is also shown that the current-fed converters can be implemented by applying three different methods based either on intuition, explicit duality transformation or adding a capacitor at the input terminal of a conventional voltage-fed converter. The study includes dynamic characterizations that have not been presented earlier. (orig.)

Leppaeaho, J.

2011-07-01

116

Inverse dual converter (IDC) for high power dc-dc applications  

Science.gov (United States)

The inverse dual converter (IDC), suitable for high-power dc-dc conversion applications, is presented. The IDC is a voltage source converter with an ac link and has been derived from an inductor converter bridge. This capacitor commutated converter is capable of continuous voltage step-up or step-down control over a wide range without the need of a transformer. In addition to high-frequency switching the converter is characterized by soft switching techniques, reducing constraints on the ratings of the switches. The average model developed with the help of gyrator theory provides sufficient information for control strategies and design considerations. The results of gyrator modeling and computer simulation are compared with experimental results obtained from a prototype IDC.

Ehsani, M.; Husain, I.; Bilgic, M. O.

117

Digital simulation of closed loop control of bi-directional dc - dc converter  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a closed loop control of isolated boost full bridge dc-dc converter for used in Medium and High power application. Zero voltage switching is applied in all switches. The dc inputvoltage is stepped up by using a boost converter. It is inverted using a fullbridge inverter. The transformer is used to produce a higher voltage in secondary voltage side The a.c. voltage is convertedinto d.c. voltage with the help of rectifier. The open loop model there is no possiblity of maintain a constant voltage with variation of input voltage. In closed loop system is maintain a constant voltage is applied with various value of input voltage. Matlab 7.3 version is used for simulating the open loop and closed loop full bridge dc – dc converter are verified. Isolated boost converter can operate at an input voltage of 24V and the output voltage 200-260 V and average efficiency of 89% at 55khz switching frequency.

S.A. Elankurisil,

2011-02-01

118

Comparison of MPPT Algorithms for DC-DC Converters Based PV Systems  

Directory of Open Access Journals (Sweden)

Full Text Available The comparative study between two most popular algorithms technique which is incremental conductance algorithm and perturbs and observe algorithm. Two different converters buck and boost converter use for comparative in this study. Few comparison such as voltage, current and power output for each different combination has been recorded.MATLAB Simulink tools have been used for performance evaluation on energy point.

A.PRADEEP KUMAR YADAV

2013-01-01

119

Li-Ion Battery Charging with a Buck-Boost Power Converter for a Solar Powered Battery Management System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper analyzes and simulates the Li-ion battery charging process for a solar powered battery management system. The battery is charged using a non-inverting synchronous buck-boost DC/DC power converter. The system operates in buck, buck-boost, or boost mode, according to the supply voltage conditions from the solar panels. Rapid changes in atmospheric conditions or sunlight incident angle cause supply voltage variations. This study develops an electrochemical-based equivalent circuit mod...

Jaw-Kuen Shiau; Chien-Wei Ma

2013-01-01

120

Comparison of two different high performance mixed signal controllers for DC/DC converters  

DEFF Research Database (Denmark)

This paper describes how mixed signal controllers combining a cheap microcontroller with a simple analogue circuit can offer high performance digital control for DC/DC converters. Mixed signal controllers have the same versatility and performance as DSP based controllers. It is important to have an engineer experienced in microcontroller programming write the software algorithms to achieve optimal performance. Two mixed signal controller designs based on the same 8-bit microcontroller are compared both theoretically and experimentally. A 16-bit PID compensator with a sampling frequency of 200 kHz implemented in the 16 MIPS, 8-bit ATTiny26 microcontroller is demonstrated.

Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.

2006-01-01

 
 
 
 
121

Fuzzy control of the DC-DC converter used as power interface for a fuel cell  

International Nuclear Information System (INIS)

In this paper it is analyzed a feed-forward fuzzy control for PWM control of the DC-DC converter using a fuel cell as energy source. For a dynamic load the fuel cell output voltage vary in large DC range and the high DC voltage stabilization can not be a difficult task. The advantages of the forward loop after the fuel cell output voltage concerning the stability and robustness of fuzzy control are compared with the best results obtained using a well designed proportional-integral control. The Simulink models for the used blocks, simulation results, and some design consideration are presented, too. (authors)

2007-11-07

122

Averaging Method for PWM DC-DC Converters Operating in Discontinuous Conduction Mode with Feedback  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a one-cycle-average (OCA discrete-time model for PWM dc-dc converter basedonclosed-loop control method for discontinuous conduction mode (DCM is presented. It leadstoexact discrete-time mathematical representation of the OCA values of the output signal evenatlow frequency. It also provides the exact discrete-time mathematical representation oftheaverage values of other internal signals with little increase in simulation time. A comparison ofthismodel to other existing models is presented through a numerical example of boostconverter.Detailed simulation results confirm the better accuracy and speed of the proposedmodel.

N.M. ADAMALI SHAH, Mohammed S. Al-Numay

2011-08-01

123

The design of RF power supply using DC-DC converter  

International Nuclear Information System (INIS)

This paper proposes the design concept of a new RF power supply using DC-DC converters without large filter capacitors and crowbar circuits. The RF power supply is designed to get quite smoothness, fast turn off and on output characteristics. These characteristics are cleared with system simulation and a small experimental model. A 2MW (-100kV, 20A) power supply design is introduced and a view point of realization and total system efficiency are also discussed. 2 refs., 13 figs

1989-10-02

124

A VHF Class E DC-DC Converter with Self-Oscillating Gate Driver  

DEFF Research Database (Denmark)

This paper describes the analysis and design of a DC-DC converter topology which is operational at frequencies in the Very High Frequency (VHF) band ranging from 30 MHz â?? 300 MHz. The presented topology, which consists of a class E inverter, class E rectifier, and self-oscillating gate driver, is inherently resonant, and switching losses are greatly reduced by ensuring Zero Voltage Switching (ZVS) of the power semiconductor devices. A design method to ensure ZVS operation when combining the inverter, rectifier, and gate driver is provided. Several parasitic effects and their influence on converter operation are discussed, and measurement results of a 100 MHz prototype converter are presented and evaluated. The designed prototype converter verifies the described topology.

Andersen, Toke Meyer; Knott, Arnold

2011-01-01

125

Asymmetrical Interleaved DC/DC Switching Converters for Photovoltaic and Fuel Cell Applications—Part 1: Circuit Generation, Analysis and Design   

Directory of Open Access Journals (Sweden)

Full Text Available A novel asymmetrical interleaved dc/dc switching converters family intended for photovoltaic and fuel cell applications is presented in this paper. The main requirements on such applications are small ripples in the generator and load, as well as high voltage conversion ratio. Therefore, interleaved structures and voltage multiplier cells have been asymmetrically combined to generate new converters, which inherently operate indiscontinuous conduction mode. The novel family is derived from boost, buck-boost and flyback-based structures. This converter family is analyzed to obtain the design equations and synthesize a design process based on the typical requirements of photovoltaic and fuel cell applications. Finally, the experimental results validate the characteristics and usefulness of the asymmetrical interleaved converter family. 

Sergio Serna

2012-11-01

126

Systematic design approach of fuzzy PID stabilizer for DC-DC converters  

International Nuclear Information System (INIS)

DC-DC converters process electrical energy by switching between a fixed number of configurations. The objective of controlling these systems is to provide better performances, ensure closed loop stability and guarantee a simple predictable behaviour. Based on a converter averaged model, we propose, in this paper, a systematic design approach of a fuzzy PID. The choice of controller parameters stands on the whole system stability requirements. Extension of the obtained asymptotic stability to structural stability is presented to show that the developed controller ensures also a simple and predictable behaviour of the converter. Finally, we illustrate the efficiency of the proposed fuzzy PID design approach through simulations in voltage mode as well as in current mode control

2008-10-01

127

Parallel-Connected Solar Photovoltaic with Ultra Low Voltage DC/DC Converter  

Directory of Open Access Journals (Sweden)

Full Text Available In series-connected wiring scheme, the residual energy generated by partially shaded cells cannot be collected or, worse, impedes collection of power from the remaining fully illuminated cells. In this paper, a parallel-connected topology is introduced to PV panel. Each cell, connected to the dc bus paralleled with a special converter, is treated as a voltage source. The dc-dc converter is introduced to realize the method, which could work under an ultra-low-voltage (ULV. Efficiency comparison is discussed with a valid calculation. Experiments about the converter, PV cell and the parallel-connected panel are given. The results show that the novel system has a good working characteristic and the efficiency is higher than that of the conventional.

Zhiwen Yu

2013-06-01

128

Time delay control for fuel cells with bidirectional DC/DC converter and battery  

Energy Technology Data Exchange (ETDEWEB)

Transient behavior is a key property in the vehicular application of proton exchange membrane (PEM) fuel cells. A better control technology is constructed to increase the transient performance of PEM fuel cells. A steady-state isothermal analytical fuel cell model is constructed to analyze mass transfer and water transport in the membrane. To prevent the starvation of air in the PEM fuel cell, time delay control is used to regulate the optimum stoichiometric amount of oxygen, although dynamic fluctuations exist in the PEM fuel cell power. A bidirectional DC/DC converter connects the battery to the DC link to manage the power distribution between the fuel cell and the battery. Dynamic evolution control (DEC) allows for adequate pulse-width modulation (PWM) control of the bidirectional DC/DC converter with fast response. Matlab/Simulink/Simpower simulation is performed to validate the proposed methodology, increase the transient performance of the PEM fuel cell system and satisfy the requirement of energy management. (author)

Kim, Y.B. [Mechanical Engineering Department, Chonnam National University, Gwangju (Korea); Kang, S.J. [Mechatronics Engineering Department, Korea Polytechnic College V, Gwangju (Korea)

2010-08-15

129

Analyzing switched circuits to design DC-DC and DC-AC converters  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish El propósito de este artículo es presentar un análisis alternativo de circuitos conmutados para diseñar generadores de onda cuadrada, SWG (del Inglés Square Wave Generator). Un SWG puede ser diseñado usando componentes electrónicos de bajo costo, lo cual permite al lector comprender como los convert [...] idores DC-DC y DC-AC basados en la aproximación conmutada es una opción económica para introducir conceptos del análisis de redes. Los resultados experimentales muestran que las técnicas usadas permiten calcular el rango de operación no solo de los componentes electrónicos sino también del efecto que el valor de la fuente de alimentación tiene en el desempeño de los generadores. Abstract in english The purpose of this paper is to present an alternative analysis of switched circuit to design square wave generators (SWG). A SWG may be designed by using low-cost electronic components, which allows to the readers to understand how DC-DC and DC-AC converters based on the switched approach is an eco [...] nomic option to introduce network analysis concepts. Experimental results show that used techniques allow calculate the frequency range operation not only of the electronic components but also the effect of the power supply value on the generators' performance.

F., Sandoval-Ibarra; J., Mercado-Moreno; A., Lopez; R., Martínez-Rivera; T., Alba-García.

130

A DC-DC converter based powering scheme for the upgrade of the CMS pixel detector  

Science.gov (United States)

Around 2016, the pixel detector of the CMS experiment will be upgraded. The amount of current that has to be provided to the front-end electronics is expected to increase by a factor of two. Since the space available for cables is limited, this would imply unacceptable power losses in the currently installed supply cables. Therefore it is foreseen to place DC-DC converters close to the front-end electronics, allowing the provision of power at higher voltages, thereby facilitating the supply of the required currents with the present cable plant. This conference report introduces the foreseen powering scheme of the pixel upgrade. For the first time, system tests have been conducted with pixel barrel sensor modules, radiation tolerant DC-DC converters and the full power supply chain of the pixel detector. In addition, studies of the stability of different powering schemes under various conditions are summarized. In particular the impact of large and fast load variations, which are related to the bunch structure of the LHC beam, has been studied.

Feld, L.; Karpinski, W.; Klein, K.; Merz, J.; Sammet, J.; Wlochal, M.

2011-11-01

131

A Stable Control Strategy for Input-Series Output-Series Connected Boost half Bridge DC-DC Converter  

Directory of Open Access Journals (Sweden)

Full Text Available Boost half bridge DC-DC converters in the combination of an input-series and output-series (ISOS connected configuration with a stable control strategy has been investigated in this paper. A stable control strategy comprises of two loops that are current loop and voltage loop. The reference to the current loop has been chosen from the input side of the DC-DC converter. The reference to the voltage loop has been selected from the output side of the DC-DC converter. Such a reference makes the circuit configuration simple, easy and eventually results in reduced cost. The control strategy for input-series output-series (ISOS configuration of DC-DC converters is proposed to achieve equal input voltage sharing (IVS as well output voltage sharing (OVS. Furthermore, in this paper, the performance of the stable control strategy for input-series output-series (ISOS boost half bridge DC-DC converter has been observed not only for the fixed but also for the varying and continuously varying load. The proposed Stable control scheme has been developed by modeling it on MATLAB using Simulink and Simpower toolboxes. The operation of the proposed stable control strategy has been found to be satisfactory.

Shahnawaz Farhan Khahro

2013-07-01

132

Dielectric Electro Active Polymer Incremental Actuator Driven by Multiple High-Voltage Bi-directional DC-DC Converters  

DEFF Research Database (Denmark)

This paper presents driving circuit for a recently invented dielectric electro active polymer (DEAP) incremental actuator. The basic operation of such an actuator is bioinspired from the movement of an inchworm. The actuator consists of three electrically isolated, and mechanically connected capacitive sub-actuators. It needs to be driven by three high voltage (~2.5 kV) DC-DC converters, to achieve the linear incremental motion. The topology used for this application is a bi-directional flyback DC-DC converter. The control of the incremental actuator involves, implementation of digital controller used for controlling charge and discharge sequences of the individual sub-actuators, and monitoring and adjustment of the output voltages of three high voltage DC-DC converters to provide over-voltage protection capability. Three power stages of the proposed converter were experimentally tested. The experimental results and efficiency measurements are shown.

Thummala, Prasanth; Zhang, Zhe

2013-01-01

133

SSP Technology Investigation of a High-Voltage DC-DC Converter  

Science.gov (United States)

The goal of this project was to establish the feasibility of a high-voltage DC-DC converter based on a rod-array triggered vacuum switch (RATVS) for the Space Solar Power system. The RATVS has many advantages over silicon and silicon-carbide devices. The RATVS is attractive for this application because it is a high-voltage device that has already been demonstrated at currents in excess of the requirement for an SSP device and at much higher per-device voltages than existing or near-term solid state switching devices. The RATVS packs a much higher specific power rating than any solid-state device and it is likely to be more tolerant of its surroundings in space. In addition, pursuit of an RATVS-based system would provide NASA with a nearer-term and less expensive power converter option for the SSP.

Pappas, J. A.; Grady, W. M.; George, Patrick J. (Technical Monitor)

2002-01-01

134

Conventional control and fuzzy control of a dc-dc converter for machine drive  

Energy Technology Data Exchange (ETDEWEB)

Fuzzy logic or fuzzy set theory is recently getting increasing emphasis in process control applications. The paper describes an application of fuzzy logic in speed control system that uses a dc-dc converter. The fuzzy control is used to linearize the family of external characteristics of the converter in discontinuous-conduction mode occurring at light load and/or high speed. In order to compare the conventional control with the fuzzy logic control, algorithms have been developed in detail and verified by Microsoft Excel simulation. The simulation study indicates that fuzzy control is a good alternative for conventional control methods, being used particularly in non-linear complex systems ill defined or totally unknown. Where the mathematical model exists, it is useful. The applications of fuzzy set theory in power electronics are almost entirely new; fuzzy logic seems to have a lot of premises in the large industrial control field. (orig.) 2 refs.

Radoi, C.; Florescu, A. [Department of Power Electronics `Politecnica` University Bucharest (Romania)

1997-12-31

135

A Three-phase Dual Active Bridge Bidirectional ZVS DC/DC Converter  

Science.gov (United States)

This paper discusses the detailed operations of a three-phase dual active bridge bidirectional zero-voltage switching (ZVS) DC/DC converter (TPDAB) which transfers a bidirectional power flow between a 12 V net and a high voltage DC net. The converter is controlled by phase-shift-modulation (PSM) with a fixed duty cycle D=1/3. It features isolation, smoother drawing and injecting current from the 12 V net, smaller capacitances, smaller switch current stress, ZVS over a wide range, high efficiency and a large power handling capability. The mathematic model is analyzed. The soft-switching principle is described and its ZVS criterias are derived. The simulation and experimental results are provided to verify the theoretical analysis.

Xuan, Zhang; Shenghua, Huang; Guoyun, Ning

136

Buck-Converter Photovoltaic Simulator  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a Photovoltaic Simulator Simulation using Buck Converter with analysis using bode diagram. A state space simulator model is derived to provide a detail non-linear model. The PV Static Model is modified by adding a low pass filter in order to avoid an algebraic loop problem and able to analyze easier. PV simulator is realized by controlling buck converter’s current using PI Controller with reference from PV model. Then the model is linearized which is used for analysis purpose. The system is analyzed using bode diagram for its output voltage against its inputs of solar irradiance and cell’s temperature. The Load, Proportional Gain Kp, and Integral Gain Ki are varied to observe their effects into the system stability. It is noticed that the limits of gain stability system are so high at all values of load and gains so the Buck-Converter Photovoltaic Simulator, which is proposed here, can be declared as a robust system.

Y. Syaifudin

2011-10-01

137

Design and Analysis of a 24 Vdc to 48 Vdc Bidirectional DC-DC Converter Specifically for a Distributed Energy Application  

Directory of Open Access Journals (Sweden)

Full Text Available The design of a bidirectional dc-dc power converter specifically for a distributed energy application is presented. The existing two different DC voltage battery bank of the distributed generation needs to interlink each other using a bi-directional dc-dc converter in order to minimize the unbalance of the output load currents of the three inverters connected to electric grid system. Through this connection, a current can flow from one system to another or vice versa depending on which systems need the current most. Thus, unbalanced currents of the grid line have been minimized and the reliability and performance of the DER grid connected system has been increased. A detailed mathematical analysis of the converter under steady state and transient condition are presented. Mathematical models for boost and buck modes are being derived and the simulink model is constructed in order to simulate the system. Moreover, the model has been validated on the actual operation of the converter, showing that the simulated results in Matlab Simulink are consistent with the experimental ones.

Ambrosio B. Cultura II

2012-09-01

138

DC-DC switching converter based power distribution vs serial power distribution EMC strategies  

CERN Multimedia

This paper presents a detailed and comparative analysis from the electromagnetic compatibility point of view of the proposed power distributions for the SLHC tracker up-grade. The main idea is to identify and quantify the noise sources, noise distribution at the system level and the sensitive areas in the front-end electronics corresponding to both proposed topologies: The DC-DC converter based power distribution and the serial power distribution. These studies will be used to define critical points on both systems to be studied and prototyped to ensure the correct integration of the system taking critically into account the electromagnetic compatibility. This analysis at the system level is crucial to ensure the final performance of the detector using non conventional power distributions, avoiding interference problems and excessive losses that can lead to catastrophic failures or expensive and un-practical solutions.

Arteche, F; Iglesias, M; Rivetta, C; Arcega, F G; Vila, I

2009-01-01

139

A High Efficiency DC-DC Converter Topology Suitable for Distributed Large Commercial and Utility Scale PV Systems  

Energy Technology Data Exchange (ETDEWEB)

In this paper a DC-DC power converter for distributed photovoltaic plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter also allows for a simplified maximum power point tracker design using fewer measurements

Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Steigerwald, Robert L; Sabate, Juan A; Chi, Song; McCann, Adam J; Zhang, Li; Mueller, Frank

2012-09-01

140

GENERAL: Self-Stable Chaos Control of dc—dc Converter  

Science.gov (United States)

A new concept related to self-stable chaos control is first put forward, and its theoretical basis and realization are presented from the frequency-domain perspective. With a new analogous-circuit realization of this control its applications in the voltage-mode Buck converter is discussed. The harmonic-balance method is applied to determine the control range of the control parameter. The experiment results given in the last part confirm the validity of the proposed control method.

Lu, Wei-Guo; Zhou, Luo-Wei; Wu, Jun-Ke

2009-03-01

 
 
 
 
141

The Study of MOSFET Parallelism in High Frequency DC/DC Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The study of MOSFET parallelism and the impact on body diode conduction loss of the switch are presented in this paper. The simulation is carried out for synchronous rectifier buck converter (SRBC) in continuous conduction mode where several configurations of the MOSFET connected in parallel are applied. It is found that the body diode conduction loss has been reduced of more than 35 % in fourparallel S1 with one S2 compared to the single pair totempoled switched SRBC circuit.

Yahaya, N. Z.; Makhtar, N. A.

2012-01-01

142

Dynamic analysis of the input-controlled buck converter fed by a photovoltaic array  

Directory of Open Access Journals (Sweden)

Full Text Available The control of the input voltage of DC-DC converters is frequently required in photovoltaic applications. In this special situation, unlike conventional converters, the output voltage is constant and the input voltage is controlled. This paper deals with the analysis and the control of the buck converter with constant output voltage and variable input.O controle da tensão de entrada de conversores DC-DC é freqüentemente necessário em aplicações com energia fotovoltaica. Nesta situação especial, diferentemente do que ocorre com conversores convencionais, a tensão de saída é constante e a tensão de entrada é variável. Este artigo versa sobre a análise e o controle do conversor buck com tensão de saída constante e tensão de entrada variável.

Marcelo Gradella Villalva

2008-12-01

143

High efficiency and low electromagnetic interference boost DC–DC converter  

Science.gov (United States)

A synchronous boost DC–DC converter with an adaptive dead time control (DTC) circuit and anti-ringing circuit is presented. The DTC circuit is used to provide adjustable dead time and zero inductor current detection for power transistors and therefore, a high efficiency is achieved by minimizing power losses, such as the shoot-through current loss, the body diode conduction loss, the charge-sharing loss and the reverse inductor current loss. Simultaneously, a novel anti-ringing circuit controlled by the switching sequence of power transistors is developed to suppress the ringing when the converter enters the discontinuous conduction mode (DCM) for low electromagnetic interference (EMI) and additional power savings. The proposed converter has been fabricated in a 0.6 ?m CDMOS technology. Simulation and experimental results show that the power efficiency of the boost converter is above 81% under different load currents from 10 to 250 mA and a peak efficiency of 90% is achieved at about 100 mA. Moreover, the ringing is easily suppressed by the anti-ringing circuit and therefore the EMI noise is attenuated.

Yajun, Li; Xinquan, Lai; Qiang, Ye; Bing, Yuan

2014-04-01

144

Basic circuits to design switched-based DC-DC converters  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish El propósito de este artículo es doble. Por un lado, se presentan conceptos básicos de circuitos conmutados para diseñar un convertidor CD-CD y, por el otro, se rescatan definiciones de electrónica de potencia asociadas a redes eléctricas simples. En el análisis de esas redes es necesario tomar en c [...] uenta no solo las no idealidades de los convertidores sino también cómo minimizar pérdidas de potencia. Porque las perdidas de potencia pueden ser minimizadas aumentando la frecuencia de reloj de los convertidores conmutados, se presentan resultados experimentales de generadores de reloj. Estos circuitos fueron implementados con componentes de bajo costo Abstract in english The purpose of this paper is twofold. On one hand, basics on switched circuits for designing a DC-DC converter are presented and, on the other hand, power electronics definitions associated with simple electrical networks are mentioned. In the analysis of these networks, it is necessary to take into [...] account not only converters' non-idealities but also how to minimize power losses. Since power losses may be minimized by increasing the clock frequency of switched-based converters, experimental results of basic clock generators are presented. These generators were implemented with low-cost components

Sandoval-Ibarra, F; Mercado-Moreno, J.R; Urióstegui-Vázquez, L.H.

145

Basic circuits to design switched-based DC-DC converters  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this paper is twofold. On one hand, basics on switched circuits for designing a DC-DC converter are presented and, on the other hand, power electronics definitions associated with simple electrical networks are mentioned. In the analysis of these networks, it is necessary to take into account not only converters' non-idealities but also how to minimize power losses. Since power losses may be minimized by increasing the clock frequency of switched-based converters, experimental results of basic clock generators are presented. These generators were implemented with low-cost componentsEl propósito de este artículo es doble. Por un lado, se presentan conceptos básicos de circuitos conmutados para diseñar un convertidor CD-CD y, por el otro, se rescatan definiciones de electrónica de potencia asociadas a redes eléctricas simples. En el análisis de esas redes es necesario tomar en cuenta no solo las no idealidades de los convertidores sino también cómo minimizar pérdidas de potencia. Porque las perdidas de potencia pueden ser minimizadas aumentando la frecuencia de reloj de los convertidores conmutados, se presentan resultados experimentales de generadores de reloj. Estos circuitos fueron implementados con componentes de bajo costo

F Sandoval-Ibarra

2007-12-01

146

Step-by-Step Design of an FPGA-Based Digital Compensator for DC/DC Converters Oriented to an Introductory Course  

Science.gov (United States)

In this paper, a short introductory course to introduce field-programmable gate array (FPGA)-based digital control of dc/dc switching power converters is presented. Digital control based on specific hardware has been at the leading edge of low-medium power dc/dc switching converters in recent years. Besides industry's interest in this topic, from…

Zumel, P.; Fernandez, C.; Sanz, M.; Lazaro, A.; Barrado, A.

2011-01-01

147

Design and Simulation of a soft switching scheme for a dc-dc Boost Converter with pi controller  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the design of simple but powerful soft switching scheme for a DC-DC Boost Converter with a closed loop control. A new novel soft switching scheme is proposed with a single switch and minimum components which offers load independent operations. The only switch used in this converter is switched ON at zero current and switched OFF at zero voltage .The proposed Controller is used to improve the dynamic performance of DC-DC converter by achieving a robust output voltage against load disturbances. The duty cycle of the Boost converter is controlled by PI Controller. A 50W/50KHz soft switched PWM Boost converter is simulated and analyzed. The results are simulated using PSIM

X.Felix Joseph

2010-10-01

148

High Current Planar Transformer for Very High Efficiency Isolated Boost DC-DC Converters  

DEFF Research Database (Denmark)

This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac-resistance and transformer leakage inductance. Design and optimization procedures are validated based on an experimental prototype of a 6 kW dcdc isolated full bridge boost converter developed on fully planar magnetics. The prototype is rated at 30-80 V 0-80 A on the low voltage side and 700-800 V on the high voltage side with a peak efficiency of 97.8% at 80 V 3.5 kW. Results highlights that thick copper windings can provide good performance at low switching frequencies due to the high transformer filling factor. PCB windings can also provide very high efficiency if stacked in parallel utilizing the transformer winding window in an optimal way.

Pittini, Riccardo; Zhang, Zhe

2014-01-01

149

Fast response double series resonant high-voltage DC-DC converter  

Science.gov (United States)

In this paper, a novel double series resonant high-voltage dc-dc converter with dual-mode pulse frequency modulation (PFM) control scheme is proposed. The proposed topology consists of two series resonant tanks and hence two resonant currents flow in each switching period. Moreover, it consists of two high-voltage transformer with the leakage inductances are absorbed as resonant inductor in the series resonant tanks. The secondary output of both transformers are rectified and mixed before supplying to load. In the resonant mode operation, the series resonant tanks are energized alternately by controlling two Insulated Gate Bipolar Transistor (IGBT) switches with pulse frequency modulation (PFM). This topology operates in discontinuous conduction mode (DCM) with all IGBT switches operating in zero current switching (ZCS) condition and hence no switching loss occurs. To achieve fast rise in output voltage, a dual-mode PFM control during start-up of the converter is proposed. In this operation, the inverter is started at a high switching frequency and as the output voltage reaches 90% of the target value, the switching frequency is reduced to a value which corresponds to the target output voltage. This can effectively reduce the rise time of the output voltage and prevent overshoot. Experimental results collected from a 100-W laboratory prototype are presented to verify the effectiveness of the proposed system.

Lee, S. S.; Iqbal, S.; Kamarol, M.

2012-10-01

150

High-Temperature SOI/SiC-Based DC-DC Converter Suite  

Directory of Open Access Journals (Sweden)

Full Text Available A complete design strategy (mechanical and electrical for a 25 W 28 V/5 V dc-dc converter utilizing SiC and SOI electronics is presented. The converter includes a high-temperature SOI-based PWM controller featuring 150 kHz operation, a PID feedback loop, maximum duty cycle limit, complementary or symmetrical outputs, and a bootstrapped high-side gate driver. Several passive technologies were investigated for both control and power sections. Capacitor technologies were characterized over temperature and over time at 300C∘, power inductors designed and tested up to 350C∘, and power transformers designed and tested up to 500C∘. Northrop Grumman normally-off SiC JFETs were used as power switches and were characterized up to 250C∘. Efficiency and mass optimization routines were developed with the data gained from the first prototype. The effects of radiation on SiC and SOI electronics are then discussed. The results of the first prototype module are presented, with operation from 25C∘ up to an ambient temperature of 240C∘ .

Brice McPherson

2008-08-01

151

Dynamic analysis of the input-controlled buck converter fed by a photovoltaic array  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O controle da tensão de entrada de conversores DC-DC é freqüentemente necessário em aplicações com energia fotovoltaica. Nesta situação especial, diferentemente do que ocorre com conversores convencionais, a tensão de saída é constante e a tensão de entrada é variável. Este artigo versa sobre a anál [...] ise e o controle do conversor buck com tensão de saída constante e tensão de entrada variável. Abstract in english The control of the input voltage of DC-DC converters is frequently required in photovoltaic applications. In this special situation, unlike conventional converters, the output voltage is constant and the input voltage is controlled. This paper deals with the analysis and the control of the buck conv [...] erter with constant output voltage and variable input.

Villalva, Marcelo Gradella; Ruppert Filho, Ernesto.

152

Design, optimization and new solutions for DC/DC converters in hybrid vehicles; Design, Optimierung und neue Loesungen fuer DC/DC-Wandler in Hybridfahrzeugen  

Energy Technology Data Exchange (ETDEWEB)

Especially in automotive engineering, the big aim of electronic device development is to combine minimum possible weight, highest efficiency and low electromagnetic interference. Since there is a wide range of energy storage devices and power consumption requirements are very versatile, there are many possible solutions for electronic power devices, but not all of them will be appropriate for each system. One possible solution concerning dc/dc converters is represented by the phase shift operation for full bridge topologies. This procedure is used for supplying the electrical 14 V system from the high voltage energy storage or, in the other direction, charge the HV battery from the 14 V net or even from an external 230 V / 400 ac net. Finepower has developed 2 prototypes for research, which are presented in this contribution. Another new topology, a bidirectional LLC Converter, is presented as well. Energy consumption is growing and the available space for electronic power devices is held very small, so the power density increases and thermal management becomes more difficult. As dimensions of bus bars, semiconductors or inductive components are shrinking, parasitic influence becomes more and more significant. For getting information about function and influence of parasitics of electronic power devices, simulation is a very important tool since it saves much time and gives the possibility to extract internal dimensions of electrical circuits which cannot be measured in reality. (orig.)

Pledl, Georg; Lutter, Peter [Finepower GmbH, Ismaning (Germany)

2010-07-01

153

A 1.6-kW, 110-kHz dc-dc converter optimized for IGBT's  

Science.gov (United States)

A full bridge dc-dc converter using a zero-current and zero-voltage switching technique is described. This circuit utilizes the characteristics of the IGBT to achieve power and frequency combinations that are much higher than previously reported for this device. Experimental results are included for a 1.6-kW, 110-kHz converter with 95 percent efficiency.

Chen, Keming; Stuart, Thomas A.

1993-01-01

154

Development of a Novel Bi-Directional Isolated Multiple-Input DC-DC Converter  

Energy Technology Data Exchange (ETDEWEB)

There is vital need for a compact, lightweight, and efficient energy-storage system that is both affordable and has an acceptable cycle life for the large-scale production of electric vehicles (EVs) and hybrid electric vehicles (HEVs). Most of the current research employs a battery-storage unit (BU) combined with a fuel cell (FC) stack in order to achieve the operating voltage-current point of maximum efficiency for the FC system. A system block diagram is shown in Fig.1.1. In such a conventional arrangement, the battery is sized to deliver the difference between the energy required by the traction drive and the energy supplied by the FC system. Energy requirements can increase depending on the drive cycle over which the vehicle is expected to operate. Peak-power transients result in an increase of losses and elevated temperatures which result in a decrease in the lifetime of the battery. This research will propose a novel two-input direct current (dc) dc to dc converter to interface an additional energy-storage element, an ultracapacitor (UC), which is shown in Fig.1.2. It will assist the battery during transients to reduce the peak-power requirements of the battery.

Li, H.

2005-10-24

155

Total ionizing dose effects of DC-DC power converter used in satellite  

International Nuclear Information System (INIS)

The total ionizing dose effects and annealing effects of DVHF2812DF and DVTR2815DF DC-DC power converters were investigated. The typical electrical parameters, such as input current, output current, output voltage, and input current of inhibition mode, as functions of the total dose with different loads and different input voltages were discussed. The relationships between these parameters and the annealing time were observed. The experiment results show that when annealing at room temperature, the trapped holes in deeper energy levels anneal little, which results in dramatic changes of the electric parameters of the DVHF2812DF device when irradiated with extra dose irradiation. However, these parameters go back to the initial values when annealing at high temperature. There are more changes of the electric parameters under the full power loaded situation than other conditions. The input current under inhibition mode can be considered as a sensitive parameter in the evaluation of the radiation-hardened levels of the devices. (authors)

2011-07-01

156

Efficiency and Cost Comparison of Si IGBT and SiC JFET Isolated DC/DC Converters  

DEFF Research Database (Denmark)

Silicon carbide (SiC) and other wide band gap devices are in these years undergoing a rapid development. The need for higher efficiency and smaller dimensions are forcing engineers to take these new devices in to considerations when choosing semiconductors for their converters. In this article a Si based converter and a SiC based converter is compared. Both converters are isolated DC/DC converters and were designed for 5 kW nominal outputs. Test setups for both converters were built and tested. The hardware differences between the two converters are described and performance is compared. An efficiency of above 97 % for the SiC JFET and over 90 % for the SI IGBT converter was measured. Cost differences between the two converters have been analyzed, showing that 772 days of operation are needed for the SiC converter costs to break even with the Si IGBT converter costs.

Nielsen, Rasmus �rndrup; Török, Lajos

2013-01-01

157

Efficiency and cost comparison of Si IGBT and SiC JFET isolated DC/DC converters  

DEFF Research Database (Denmark)

Silicon carbide (SiC) and other wide band gap devices are in these years undergoing a rapid development. The need for higher efficiency and smaller dimensions are forcing engineers to take these new devices in to considerations when choosing semiconductors for their converters. In this article a Si based converter and a SiC based converter is compared. Both converters are isolated DC/DC converters and were designed for 5 kW nominal outputs. Test setups for both converters were built and tested. The hardware differences between the two converters are described and performance is compared. An efficiency of above 97 % for the SiC JFET and over 90 % for the SI IGBT converter was measured. Cost differences between the two converters have been analyzed, showing that 772 days of operation are needed for the SiC converter costs to break even with the Si IGBT converter costs.

Nielsen, Rasmus �rndrup; Török, Lajos

2013-01-01

158

Design and Implementation of Anti-windup PI Control on DC-DC Bidirectional Converter for Hybrid Vehicle Applications  

Directory of Open Access Journals (Sweden)

Full Text Available Well-regulated DC bus voltage is the important point to guarantee power demand fulfillment in hybrid vehicle applications. Voltage regulation can be achieved with control method that determines switching signal on DC-DC converter. This paper describes the design and small scale experiment results of bus voltage regulation control for  DC-DC bidirectional converter with battery and supercapacitor as energy sources. The control system consisted of two control loops. The outer loop got DC bus voltage feedback using anti-windup PI back calculation control method. This outer loop would generate a reference current for the inner loop that implemented hysteresis control. The inner control loop compared that reference curent with the source current obtained from the current sensor. Simulation and experiment results showed that bus voltage was well-regulated under the load changes of 1% ripple voltage

Muh. Zakiyullah Romdlony

2012-07-01

159

A Novel Two Switch Non-inverting Buck-Boost Converter based Maximum Power Point Tracking System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A solar module can’t transfer maximum power to the load itself due to impedance mismatch. A maximum power point tracking (MPPT) system could be employed to have the maximum power.  A new MPPT system has been developed using Buck-Boost type DC-DC converter. The system is highly efficient and robust. PIC16F73 microcontroller has been used to control the DC-DC converter output. PV module output power is measured using microcontroller. The output power is compared with the previous module outp...

Khandker Tawfique Ahmed; Mithun Datta; Nur Mohammad

2013-01-01

160

Design and Robustness Analysis of a PID Based Sliding Mode Controller for a dc-dc Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study deals with the design and analysis of a dc-dc converter operating in continuous conduction mode with Proportional-Integral-Derivative control and PID based Sliding Mode Control (SMC). A small signal model is developed using Switching Flow Graph (SFG) from which the control coefficients for the PID controller is selected. PID based SMC uses a control law which constrains the weighted sum of the voltage error, its derivatives and the integral of the voltage error to zero. The equival...

2012-01-01

 
 
 
 
161

Using Nyquist or Nyquist-Like Plot to Predict Three Typical Instabilities in DC-DC Converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

By transforming an exact stability condition, a new Nyquist-like plot is proposed to predict occurrences of three typical instabilities in DC-DC converters. The three instabilities are saddle-node bifurcation (coexistence of multiple solutions), period-doubling bifurcation (subharmonic oscillation), and Neimark bifurcation (quasi-periodic oscillation). In a single plot, it accurately predicts whether an instability occurs and what type the instability is. The plot is equival...

Fang, Chung-chieh

2012-01-01

162

An Efficiency-Optimized Isolated Bidirectional DC-DC Converter with Extended Power Range for Energy Storage Systems in Microgrids  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a novel extended-single-phase shift (ESPS) control strategy of isolated bidirectional full-bridge DC-DC converters (IBDCs) which are a promising alternative as a power electronic interface in microgrids with an additional function of galvanic isolation. Based on the mathematical models of ESPS control under steady-state conditions, detailed theoretical and experimental analyses of IBDC under ESPS control are presented. Compared with conventional single-phase-shift (CSPS) c...

Xiaolong Shi; Jiuchun Jiang; Xintao Guo

2012-01-01

163

SWITCH MODE PULSE WIDTH MODULATED DC-DC CONVERTER WITH MULTIPLE POWER TRANSFORMERS  

DEFF Research Database (Denmark)

A switch mode pulse width modulated DC-DC power converter comprises at least one first electronic circuit on a input side (1) and a second electronic circuit on a output side (2). The input side (1) and the output side (2) are coupled via at least two power transformers (T1, T2). Each power transformer (T1, T2) comprises a first winding (T1a, T2a) arranged in a input side converter stage (3, 4) on the input side (1) and a second winding (T1 b, T2b) arranged in a output side converter stage (5) on the output side (2), and each of the windings (T1a, T1 b, T2a, T2b) has a first end and a second end. The first electronic circuit comprises terminals (AO, A1) for connecting a source or a load, at least one energy storage inductor (L) coupled in series with at least one of the first windings (T1a, T2a) of the power transformers (T1, T2), and for each power transformer (T1, T2), an arrangement of switches being adapted to switch the current through the first winding (T1 a, T2a) between a first ON-state, a first OFF-state, a second ON-state with a polarity opposite to the first ON-state, and a second OFF-state, and/or being adapted to provide rectified current to the terminals (AO, A1) wherein the at least one energy storage inductor (L) is arranged so as to be charged, when all switches of the switching arrangements are conducting, and the current through the at least one first winding coupled in series to the energy storage inductor is in an OFF- state. The second electronic circuit comprises terminals (BO, B1) for connecting a load or a source, a single arrangement of switches being adapted to switch the current through the second windings (T1 b, T2b) of the power transformers (T1, T2) between a first ON-state, a first OFF-state, a second ON-state with a polarity opposite to the first ON-state, and a second OFF-state, and/or being adapted to provide rectified current to the terminals (BO, B1). The second windings (T1b, T2b) of the power transformers (T1, T2) are connected in series and coupled via the single arrangement of switches of the second circuit to the terminals (BO, B1) of the output side.

Nymand, Morten Technical University of Denmark,

164

Dual-Input Isolated Full-Bridge Boost DC-DC Converter Based on the Distributed Transformers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, a new two-input isolated boost dc-dc converter based on a distributed multi-transformer structure which is suitable for hybrid renewable energy systems is investigated and designed. With a novel transformer winding-connecting strategy, the two input ports can be decoupled completely, so the proposed converter can draw the power from the two different dc sources, which have low output voltage, and transfer it to the dc bus, which has high voltage, separately or simultaneously. T...

Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.; Nielsen, Henning R.

2012-01-01

165

Design and Analysis of a 24 Vdc to 48 Vdc Bidirectional DC-DC Converter Specifically for a Distributed Energy Application  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The design of a bidirectional dc-dc power converter specifically for a distributed energy application is presented. The existing two different DC voltage battery bank of the distributed generation needs to interlink each other using a bi-directional dc-dc converter in order to minimize the unbalance of the output load currents of the three inverters connected to electric grid system. Through this connection, a current can flow from one system to another or vice versa depending on which system...

Cultura Ii, Ambrosio B.; Salameh, Ziyad M.

2012-01-01

166

A Zvs Dc-Dc Converter With Specific Voltage Gain For Inverter Operation Used For 3-Phase Induction Motor Operation  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract:zero-voltage-switching (ZVS dc?dc converter with specific voltage gain is proposed . The specific voltage is utilized for inverter operation for supplying 3-phase domestic load. It consists of a ZVS boost converter stage and a ZVS half-bridge converter stage and two stages are merged into a single stage. The ZVS boost converter stage provides a continuous input current and ZVS operation of the power switches. The ZVS half-bridge converter stage provides a high voltage gain. The principle of operation and system analysis are presented. The specific voltage is used to obtain a 200 volts Line to Line RMS AC supply through inverter operation. The supply is in turn used for a 3-Phase load like operation and speed control of 3-Phase Squirrel cage Induction motor. Keywords: Boost converter, Zero voltage switching, Coupled inductor, Specific voltage gain, Soft switching technique, Inverter, Speed control of Induction motor.

ANIL KUMAR REDDY.K, SIRISHA.S

2013-08-01

167

Hybrid electric system based on fuel cell and battery and integrating a single dc/dc converter for a tramway  

International Nuclear Information System (INIS)

Research highlights: ? Hybrid electric power system for a real surface tramway. ? Hybrid system based on PEM fuel cell with dc/dc converter and Ni-MH battery. ? New control strategy for the energy management of the tramway. ? Hybrid system demonstrated to meet appropriate driving cycle of the tramway. -- Abstract: This paper presents a hybrid electric power system for a real surface tramway. The hybrid system consists of two electrical energy sources integrating a single dc/dc converter to provide the power demanded by the tramway loads (four electric traction motors and auxiliary services): (1) a Polymer Electrolyte Membrane (PEM) fuel cell (FC) as the primary and (2) a rechargeable Ni-MH battery as electrical energy storage to supplement the FC over the driving cycle. According to the requirements of the real driving cycle of the tramway, it was considered a 200 kW PEM FC system with two FCs connected in parallel and a 34 Ah Ni-MH battery. The PEM FC and Ni-MH battery models were designed from commercially available components. The power conditioning system provides the appropriate power for the tramway. It is composed of: (1) a unique dc/dc boot converter which adapts the FC output voltage to the 750 V traction standard dc bus; (2) three phase inverters to drive properly each electric motors; and (3) a braking chopper to dissipate excess of regenerative braking energy. Suitable state machine control architecture is presented for the hybrid system, its objective being to provide demanded power by the driving cycle, optimizing the energy generated. Following this objective, a new state machine control strategy based on eight states decides the operating point of each component of the system and a cascade control structure allows achieving the operating points determined by the strategy. Simulation results of the real driving cycle of the tramway check the adequacy of the hybrid electric power system.

2011-05-01

168

Design of Performance Driven Self-Tuning PID Control Systems and It's Application for DC-DC Converters  

Science.gov (United States)

This paper proposes an adaptive PID controller which is driven by current control performance. The calculations of the PID parameters are based on the generalized minimum variance control(GMVC) algorithm. The current control performance is obtained in an online manner over a user-specified time-window with some overlap. The retuning of PID parameters are only carried out when controller performance deteriorates below a user-specified threshold. Experimental evaluations on the voltage control of the DC-DC converter demonstrates the practicality and utility of this idea.

Ohnishi, Yoshihiro; Ikemoto, Takahiro; Yamamoto, Toru

169

Asymmetrical Interleaved DC/DC Switching Converters for Photovoltaic and Fuel Cell Applications—Part 2: Control-Oriented Models  

Directory of Open Access Journals (Sweden)

Full Text Available A previous article has presented the members of the asymmetrical interleaved dc/dc switching converters family as very appropriate candidates to interface between photovoltaic or fuel cell generators and their loads because of their reduced ripple and increased current processing capabilities. After a review of the main modeling methods suitable for high-order converters operating, as the asymmetrical interleaved converters (AIC ones, in discontinuous current conduction mode a full-order averaged model has been adapted and improved to describe the dynamic behavior of AIC. The excellent agreement between the mathematical model predictions, the switched simulations and the experimental results has allowed for satisfactory design of a linear-quadratic regulator (LQR in a fuel-cell application example, which demonstrates the usefulness of the improved control-oriented modeling approach when the switching converters operate in discontinuous conduction mode.

Sergio Ignacio Serna-Garces

2013-10-01

170

Extended Phase Shift Control Of Isolated Bidirectional Dc-Dc Converter For Renewable Energy Sources Connected To Micro Grid  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract:The mankind is in dire need for maximum utilization of the available resources. Many people have suggested the application and usage of the micro grid near the load centers. These micro grids are connected to the nearby available generating stations like solar, wind etc. the generating stations cannot give a pure DC voltage for conversion in to AC. We do have some resources which cannot have optimal dc voltage for conversion. These voltage sources are combined and connected to single stage DC-AC // AC-DC conversion. This will provide a flat voltage profile for pure AC production. A phenomenon of power backflow in traditional phase shift control of isolated bidirectional full bridge dc-dc converter and analyzes the effects which backflow power act on power circulating flow and current stress. On the basis a novel extended phase shift control of isolated bidirectional dc-dc converter for power distribution in micro grid compared with traditional phase shift control extended phase shift control not only expands regulating range of transmission power and enhances regulating flexibility but also reduces the current stress and improves the system efficiency.

SURESH KUMAR REDDY. G, V.SWARUPA

2013-08-01

171

Modeling and Simulation of Non-ideal Buck Converter in DCM  

Directory of Open Access Journals (Sweden)

Full Text Available The modeling method is exemplified by Buckconverter operating in the discontinuous conduction mode(DCM, taking into account all parasitic resistances, thresholdvoltage of diode and inductor current ripples existing in actualconverters. Based on the theory of switch average model, timeaverage method of equivalent circuit, the theory of energyconservation, a circuit averaging method is studied to modelnon-ideal Buck converters operating in DCM, and a duty ratioconstraint which leads to a full order model is introduced. Onthe basis of DC circuit model and large and small-signalequivalent circuit model, the modeling and simulation analysisof non-ideal Buck converters are presented. Therefore, thederived models are convenient for modeling and designing ofDC-DC converter and its control system.

Sheng-yu Gong,

2012-04-01

172

Chaos in the buck converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Esta tesis estudia el fenómeno del caos en las ecuaciones que modelan un convertidor buck con control PWM. Desde el punto de vista matemático, contribuye al estudio de los sistemas lineales a trozos tridimensionales, con émfasis en las perspectivas geométrica y de cálculo numérico. Se consiguen resultados analíticos pero, finalmente, deben emplearse métodos numéricos para calcular efectivamente las órbitas periódicas, bifurcaciones, variedades invariantes y cuencas de atracción. D...

Olivar, Gerard

1997-01-01

173

Development of a DC-DC conversion powering scheme for the CMS Phase-1 pixel upgrade  

CERN Document Server

A novel powering scheme based on the DC-DC conversion technique will be exploited to power the CMS Phase-1 pixel detector. DC-DC buck converters for the CMS pixel project have been developed, based on the AMIS5 ASIC designed by CERN. The powering system of the Phase-1 pixel detector is described and the performance of the converter prototypes is detailed, including power efficiency, stability of the output voltage, shielding, and thermal management. Results from a test of the magnetic field tolerance of the DC-DC converters are reported. System tests with pixel modules using many components of the future pixel barrel system are summarized. Finally first impressions from a pre-series of 200 DC-DC converters are presented.

Feld, Lutz Werner; Karpinski, Waclaw; Klein, Katja; Lipinski, Martin; Preuten, Marius; Max Rauch; Rittich, David Michael; Sammet, Jan Domenik; Wlochal, Michael

2013-01-01

174

Design and Robustness Analysis of a PID Based Sliding Mode Controller for a dc-dc Converter  

Directory of Open Access Journals (Sweden)

Full Text Available This study deals with the design and analysis of a dc-dc converter operating in continuous conduction mode with Proportional-Integral-Derivative control and PID based Sliding Mode Control (SMC. A small signal model is developed using Switching Flow Graph (SFG from which the control coefficients for the PID controller is selected. PID based SMC uses a control law which constrains the weighted sum of the voltage error, its derivatives and the integral of the voltage error to zero. The equivalent control technique is used in its design which makes the converter more suitable for fixed frequency operation. Sensitivity of these controllers to supply voltage disturbances and load disturbances is studied and results are presented.

D.M. Mary Synthia Regis Prabha

2012-02-01

175

Battery charging characteristics in small scaled photovoltaic system using resonant DC-DC converter with electric isolation  

International Nuclear Information System (INIS)

The solar energy has been drawing attention of the whole world as a clean and infinite energy, since the globe resource, the globe ecology and so on came into question. The wide applications of the solar energy are being expected in a range from electric power plants to household systems. But the output power induced in the photovoltaic modules is influenced by an intensity of the solar radiation, a temperature of the solar cells and so on, so the various useful forms of the solar energy are being proposed for a purpose of stable power supply. a system described in this paper is a small scaled photovoltaic system with storage batteries. This paper describes the theoretical analyses of the photovoltaic system using a resonant DC-DC converter in order to clarify a desirable circuit condition, besides the experimental results of the battery charging characteristics are presented

1990-11-27

176

Design, Analysis and Implementation of a new topology of multi phase synchronous buck converter under current mode control  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a new PWM Multi phase DC-DC converter under current mode control with an auxiliary circuit which provides zero voltage switching in order to meet the power supply requirements of the processors of modern electronic equipments like laptops, mobiles, and PDAs etc which require more than 70 A current, lower voltage and better transient response.The multi phase topology benefits in high current, good efficiency and better current transient response. High current multi phase buck converters found applications in advanced data control, solid state lasers, communication equipment and Pentium processors etc. In this paper designed of three phase DC-DC converter 100W, 12V/1V under current mode control is discussed in detail and the simulation results are presented to support the theoretical analysis.

Nittala S K Sastry

2012-06-01

177

DC-DC Converters Using PID Controller and Pulse Width Modulation Technique  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a boost converter along with a flyback converter. The Zero Voltage Switching (ZVS technique is used to achieve soft switching. A bidirectional boost converter is connected with an output module as a Parallel Input Serial Output configuration. The flyback converter with Voltage Doubler Rectifier (VDR acts as an output module. This connection makes a bidirectional boost converter an active clamp circuit which is connected to the output side in order to extend the step up ratio. A converter with active clamp technique is used to recycle the leakage energy, to eliminate voltage spike due to coupled inductors and also to provide a mechanism to achieve ZVS. To overcome the efficiency degradation during light load due to load dependent soft switching of the ZVS, a control method using Pulse Width Modulation (PWM proportional to the load current is used.

R.Sudha

2014-01-01

178

Linear-assisted DC-DC switching converter with constant switching frequency  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article shows the proposal of a linear–assisted converter or linear–&–switching hybrid converter with a constant switching frequency. The control loop of the system is based on the current–mode technique. The main disadvantage of a converter with current–mode control is the inherent instability of the loop when switch duty ratios are greater than 0.5. In order to make stable the proposed linear–assisted converter, the article shows the technique based on a slope compensation.

Marti?nez Garci?a, Herminio; Grau Saldes, Antoni; Bolea Monte, Yolanda; Ga?miz Caro, Juan

2011-01-01

179

Linear–assisted DC-DC switching converter with constant switching frequency  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article shows the proposal of a linear–assisted converter or linear–&–switching hybrid converter with a constant switching frequency. The control loop of the system is based on the current–mode technique. The main disadvantage of a converter with current–mode control is the inherent instability of the loop when switch duty ratios are greater than 0.5. In order to make stable the proposed linear–assisted converter, the article shows the technique based on a slope compensation.

Marti?nez Garci?a, Herminio; Grau Saldes, Antoni; Bolea Monte, Yolanda; Ga?miz Caro, Juan

2011-01-01

180

Optimal Design of a Push-Pull-Forward Half-Bridge (PPFHB) Bidirectional DC–DC Converter With Variable Input Voltage  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a low-cost bidirectional isolated dc–dc converte, derived from dual-active-bridge converter for the power sources with variable output voltage like supercapacitors. The proposed converter consists of push-pull-forward circuit half-bridge circuit (PPFHB) and a high-frequency transformer; this structure minimizes the number of the switching transistors and their associate gate driver components. With phase-shift control strategy, all the switches are operated under zero-vo...

Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

2012-01-01

 
 
 
 
181

Modeling and control of isolated full bridge boost DC-DC converter implemented in FPGA  

DEFF Research Database (Denmark)

In this paper an isolated full bridge boost converter (IFBC) firstly is modeled. In the modeling part, a small signal equivalent of the converter is developed. From the small signal model, the converter transfer function is derived. Based on the obtained transfer function, challenges of controller design are discussed. In the next step a digital PI controller is designed and implemented in a FPGA to control the output voltage. Using the injection transformer method the open loop transfer function in closed loop is measured and modeling results are verified by experimental results. © 2013 IEEE.

Taeed, Fazel; Nymand, M.

2013-01-01

182

Multilevel modular DC/DC converter for regenerative braking using supercapacitors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Regenerative braking is presented in many electric traction applications such as electric and hybrid vehicles, lifts and railway. The regenerated energy can be stored for future use, increasing the efficiency of the system. This paper outlines the benefits of the MMC (modular multilevel converter) in front of the cascaded or series connection of converters to achieve high voltage from low voltage storage elements such as supercapacitors. The paper compares three different solutions and sho...

Massot Campos, Miquel; Montesinos Miracle, Daniel; Bergas Jane?, Joan Gabriel; Rufer, Alfred

2012-01-01

183

DC-DC converters in distributed photovoltaic electricity system. Analysis, control and design  

Energy Technology Data Exchange (ETDEWEB)

This thesis presents a comprehensive review on switched-mode converters in terms of dynamic behavior and practical limitations that arise from the fundamental properties of the electrical sources and loads, control engineering principles and topological properties of the converters. The main focus is on analyzing the behavior of a single converter used to interface a photovoltaic generator into a high-voltage dc link. The main objective is to introduce interfacing principles with numerous examples and a thorough discussion. The interfacing of photovoltaic generators by means of switched-mode converters has proven to be problematic according to numerous scientific publications indicating operational disadvantages and anomalies. The output characteristics of the photovoltaic generator, which are bound to varying environmental conditions, introduce design challenges. It has been recognized recently that the photovoltaic generator does not contain similar electrical behavior as conventional electrical sources, most notably due to its limited-power characteristics, yielding two distinctive operating regions. Yet, the constraints arising from the properties of the source have not been completely recognized, although the effect of these constraints can be seen from the published research results. When switched-mode converters are used to adapt individual photovoltaic modules into larger system by connecting converters in series or in parallel, severe operational limitations are observed. On the other hand, if the photovoltaic generator is substituted with a source that does not contain similar characteristics, observations may lead to misconclusions as the effect of the photovoltaic generator is not properly modeled. Therefore, claims that are not valid for actual applications with photovoltaic generators may be presented and widely accepted. This thesis presents methods to perform proper analysis of switched-mode converters implemented in distributed photovoltaic applications, by continuing previous work around the subject. The dynamic models for series-connected and parallelconnected systems of interfacing converters are given, explaining the observed operational anomalies. Additionally, it is shown by a thorough review that the parallel configuration does not contain the claimed disadvantageous properties and actually provides better performance. A patented converter topology designed for the parallel configuration is presented with comprehensive analysis and practical validation. Finally, the problematics of photovoltaic interfacing is summarized under the interfacing constraints, which give guidelines for design and analysis of interfacing converters. (orig.)

Huusari, J.

2012-10-15

184

Analysis and Design of a Bidirectional Isolated DC-DC Converter for Fuel Cell and Super-Capacitor Hybrid System  

DEFF Research Database (Denmark)

Electrical power system in future uninterruptible power supply (UPS) or electrical vehicle (EV) may employ hybrid energy sources, such as fuel cells and super-capacitors. It will be necessary to efficiently draw the energy from these two sources as well as recharge the energy storage elements by the DC bus. In this paper, a bidirectional isolated DC-DC converter controlled by phase-shift and duty cycle for the fuel cell hybrid energy system is analyzed and designed. The proposed topology minimizes the number of switches and their associated gate driver components by using two high frequency transformers which combine a half-bridge circuit and a full-bridge circuit together on the primary side. The voltage doubler circuit is employed on the secondary side. The current-fed input can limit the input current ripple that is favorable for fuel cells. The parasitic capacitance of the switches is used for zero voltage switching (ZVS). Moreover, a phase-shift and duty cycle modulation method is utilized to control thebidirectional power flow flexibly and it also makes the converter operate under a quasi-optimal condition over a wide input voltage range. This paper describes the operation principle of the proposed converter, the ZVS conditions and the quasi-optimal design in depth. The design guidelines and considerations about the transformers and other key components are given. Finally, a 1- kW 30~50-V-input 400-V-output laboratory prototype operating at 100 kHz switching frequency is built and tested to verify the effectiveness of the presented converter.

Zhang, Zhe; Ouyang, Ziwei

2012-01-01

185

Design and Implementation of high frequency transformer for SMPS Based flyback DC-DC converter  

Directory of Open Access Journals (Sweden)

Full Text Available In switch mode power supplies (SMPS, flyback converters are very popular because of, design simplicity, low cost, multiple isolated outputs, high output voltages and high efficiency. They are preferred especially for low power applications. In this paper we have presented the design of transformer for variable DC input (18V to 60V to 12V DC output. And observed the wave form across the switch, primary & secondary of the transformer.

Prashanth R.S.

2012-12-01

186

High-Efficiency Self-Adjusting Switched Capacitor DC-DC Converter with Binary Resolution  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Switched-Capacitor Converters (SCC) suffer from a fundamental power loss deficiency which make their use in some applications prohibitive. The power loss is due to the inherent energy dissipation when SCC operate between or outside their output target voltages. This drawback was alleviated in this work by developing two new classes of SCC providing binary and arbitrary resolution of closely spaced target voltages. Special attention is paid to SCC topologies of binary resolution. Namely, SCC s...

Kushnerov, Alexander

2010-01-01

187

Stability Analysis and Control of Nonlinear Phenomena in Buck Converters Using Variable Structure Control Approach  

Directory of Open Access Journals (Sweden)

Full Text Available The time varying, nonlinear nature of the power switches and several other sources of nonlinearities in DC-DC Converters deviates its performance from the theoretical prediction of stability. The switching nature necessitates a study of the stability and their periodic orbit rather than the equilibrium point. The closed loopoperation exhibits several types of nonlinear phenomena including bifurcation, chaos and quasi-periodicity. This paper is oriented with the analysis of such nonlinear phenomena in buck converter and attempts to coin a new strategy that can control chaos and significantly extend the parameter range for nominal period-I operation, in its mission to enhance the operating range of the converter.

Dr. S. R. PARANJOTHI,

2011-01-01

188

Design and Control of a Multiple Input DC/DC Converter for Battery/Ultra-capacitor Based Electric Vehicle Power System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Battery/Ultra-capacitor based electrical vehicles (EV) combine two energy sources with different voltage levels and current characteristics. This paper focuses on design and control of a multiple input DC/DC converter, to regulate output voltage from different inputs. The proposed multi-input converter is capable of bi-directional operation and is responsible for power diversification and optimization. A fixed switching frequency strategy is considered to control its operating modes. A portio...

2009-01-01

189

An Efficiency-Optimized Isolated Bidirectional DC-DC Converter with Extended Power Range for Energy Storage Systems in Microgrids  

Directory of Open Access Journals (Sweden)

Full Text Available This paper proposes a novel extended-single-phase shift (ESPS control strategy of isolated bidirectional full-bridge DC-DC converters (IBDCs which are a promising alternative as a power electronic interface in microgrids with an additional function of galvanic isolation. Based on the mathematical models of ESPS control under steady-state conditions, detailed theoretical and experimental analyses of IBDC under ESPS control are presented. Compared with conventional single-phase-shift (CSPS control, ESPS control can greatly improve the efficiency of IBDCs in microgrids through decreasing current stress and backflow power considerably over a wide input and output voltage range under light and medium loads. In addition, ESPS control only needs to adjust one single phase-shift angel to control transmission power, thus it retains implementation simplicity in comparison with dual-phase-shift (DPS control for microgrid applications. Furthermore, an efficiency-optimized modulation scheme based on ESPS and CSPS control is developed in the whole power range of IBDC for power distribution in microgrids. A 10 kW IBDC prototype is constructed and the experimental results validate the effectiveness of the proposed control strategy, showing that the proposed strategy can enhance the overall efficiency up to 30%.

Xiaolong Shi

2012-12-01

190

A NEW SOFT-SWITCHING ACTIVE CLAMP SCHEME FOR FULL-BRIDGE ISOLATED CURRENT FED DC-DC CONVERTER FED DRIVES  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents on a new high power full bridge isolated current fed dc/dc Converter with an active clamp. A proposed current fed dc/dc converter with high efficiency and voltage boosting capability is designed for use in the interface between a low voltage fuel cell source and a high voltage dc bus for inverters.ZVS scheme in all active switches is achieved for using a soft switching scheme. The switching losses and the conduction losses are reduced and the performance of the drive system should be increased from the proposed model. The proposed converter system is controlled by SPWM Technique. The simulation results are carried out and presented.

M.Geetha

2012-05-01

191

A variable step-down conversion ratio switched capacitor DC-DC converter for energy harvesting systems working in intermittent mode  

Energy Technology Data Exchange (ETDEWEB)

Energy harvesting systems stimulate the development of power management for low power consumption applications. Improving the converter efficiency of power management circuits has become a significant issue in energy harvesting system design. This paper presents a variable step-down conversion ratio switched capacitor (SC) DC-DC converter to advance the converter efficiency of charge on the stored capacitor in a wireless monitoring system of orthopedic implants. The converter is designed to work at 1 MHz switching frequency and achieves 15 to 2 V conversion. Measurement results show that the converter efficiency can reach 42% including all circuit power consumption, which is much higher than previous work. (semiconductor integrated circuits)

Hao Wenhan; Jia Chen; Chen Hong; Zhang Chun; Wang Zhihua, E-mail: haowh04@mails.tsinghua.edu.c [Tsinghua National Laboratory for Information Science and Technology, Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)

2009-12-15

192

High-Efficiency Self-Adjusting Switched Capacitor DC-DC Converter with Binary Resolution  

CERN Document Server

Switched-Capacitor Converters (SCC) suffer from a fundamental power loss deficiency which make their use in some applications prohibitive. The power loss is due to the inherent energy dissipation when SCC operate between or outside their output target voltages. This drawback was alleviated in this work by developing two new classes of SCC providing binary and arbitrary resolution of closely spaced target voltages. Special attention is paid to SCC topologies of binary resolution. Namely, SCC systems that can be configured to have a no-load output to input voltage ratio that is equal to any binary fraction for a given number of bits. To this end, we define a new number system and develop rules to translate these numbers into SCC hardware that follows the algebraic behavior. According to this approach, the flying capacitors are automatically kept charged to binary weighted voltages and consequently the resolution of the target voltages follows a binary number representation and can be made higher by increasing t...

Kushnerov, Alexander

2010-01-01

193

Experimental Discussion on a 6-kW, 2-kWh Battery Energy Storage System Using a Bidirectional Isolated DC/DC Converter  

Science.gov (United States)

This paper presents an experimental discussion on a 6-kW, full-bridge, zero-voltage switching bidirectional isolated dc/dc converter for a 53.2-V, 2-kWh Li-ion battery energy storage system. The combination of high-frequency switching devices, 600-V/200-A IGBTs and 100-V/500-A MOSFETs with a high-frequency transformer reduces the weight and physical size of the bidirectional isolated dc/dc converter. The dc voltage on the high-voltage side of the converter is controlled in a range of 300V to 355V as the battery voltage on the low-voltage side varies from 50V to 59V. Experimental verification of bidirectional power flow into (battery charging) or out of (battery discharging) the Li-ion battery bank is also presented. The maximal efficiency of the dc/dc converter is measured to be 98.1% during charging and 98.2% during discharging, excluding the gate drive loss and control circuit loss.

Abe, Takahiro; Tan, Nadia Mei Lin; Akagi, Hirofumi

194

Advanced Energy Conversion System Using Sinusoidal Voltage Tracking Buck-Boost Converter Cascaded Polarity Changing Inverter  

Science.gov (United States)

This paper presents an advanced power converter employs a sinusoidal voltage absolute value tracking buck-boost DC-DC converter in the first power processing stage and a polarity changing full-bridge inverter in the second stage. The proposed power conversion system has the capability of delivering sinusoidal output and input current with unity power factor and good output voltage regulation. Consequently, the complete voltage regulator system, which is mainly suitable for new energy generation systems as well as energy storage systems, can be constructed compactly and inexpensively without DC link electrolytic capacitor. Also, the paper presents an auxiliary passive resonant circuit for soft switching operation. Simulation results using PSIM software are presented to verify the operation principles and feasibility of the proposed power conversion system.

Ahmed, Nabil A.

2011-06-01

195

Improved Dynamic Response of Buck Converter using Fuzzy Controller  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents comparative performance of Buck Converter in both open as well as closed loop. With the help state equations Mathematical Model of Buck Converter is designed in MATLAB/SIMULINK. The obtained output response of open loop Buck Converter is sluggish, not optimum and consists of peak overshoots. PI Controller is used in closed loop model of Buck Converter. Output Voltage is compared with a reference signal, which then is processed through a controller (PI/Fuzzy. The obtained signal is superimposed with a carrier signal and given to switching device used. To further optimize the performance of Buck Converter and eliminate the peak overshoot present in output response, Fuzzy controller is used. Here Suguno type Fuzzy is used.

Nagulapati Kiran

2014-03-01

196

Digital Linear and Nonlinear Controllers for Buck Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Both linear PID controllers and fuzzy controllers are designed and implemented for a buck converter. Comparison between the two controllers is made in the aspect of design, implementation and experimental results. Design of fuzzy controllers is based on heuristic knowledge of the converter and tuned using trial and error, while the design of linear PID and PI controllers is based on the frequency response of the buck converter. Implementation of linear controllers is quite straightforward, wh...

2012-01-01

197

New silicon thin-film technology associated with original DC-DC converter: An economic alternative way to improve photovoltaic systems efficiencies  

International Nuclear Information System (INIS)

In this article, we aim at optimizing an innovative tandem structure based on polymorphous and microcrystalline silicon for the top and bottom elementary cells, respectively, combined with an original DC-DC converter. The studied tandem structure is composed of two cells, each being connected to its own separate electrodes making the structure electrically decoupled but optically coupled. In those conditions, the constraint of current matching usually needed in the classical micromorph structures is avoided. As a result, the robustness against the current variations is enhanced and the efficiency of the structure is improved. Since the top cell plays the main role in the determination of the transmitted part of the incoming flux to the bottom cell, the thickness of the intrinsic layer of the polymorphous cell is tuned so that the output power of the global structure becomes maximal. To implement the electric decoupling of two sub cells, the studied structure needs two static converters. In order to minimize the converters bulk, we design an innovative output electric architecture and its optimized related control signals. -- Highlights: ? We optimized an innovative silicon thin film 4-wires tandem solar structure. ? The sub-cells are made of polymorphous and microcrystalline silicon. ? Electric decoupling of solar sub-cells leads to avoid current matching constraint. Robustness against current variations is enhanced and the efficiency is improved. The studied structure is combined with an original DC-DC converter. ? This systemic approach improves efficiency and reduces cost of the global structure.

2011-03-01

198

Two phase interleaved buck converter for driving high power LEDs  

DEFF Research Database (Denmark)

The goal of this paper is to evaluate an interleaved buck topology for driving high current light-emitting diodes. Low output capacitor value allows the use of non-electrolytic capacitors extending the lifetime of the converter. Converter is operated as a constant, regulated current source which increases luminous efficacy of LED compared to PWM dimmed system. Because of the low dynamic resistance of LEDs the duty cycle of the converter does not change greatly with controlled current. By setting the input voltage of the buck converter to around twice the voltage of diode strings, converter can be operated close to the 50% duty cycle, where the ripple attenuation is the highest.

Beczkowski, Szymon; Munk-Nielsen, Stig

2011-01-01

199

Using super-capacitors in combination with Bi-directional DC/DC converters for active load management in residential fuel cell applications  

Energy Technology Data Exchange (ETDEWEB)

Among innovative conversion systems for alternative energy, Fuel Cells (FCs) are ideal in applications as distributed power generation or automotive. The connection of FCs to domestic or industrial loads requires a DC/AC converter also acting as a energy buffer to match the different dynamics of FCs and loads. In the last years, a new type of electrolytic capacitors called Super- Capacitors (SCs), has been designed using double layers technology. Such components are able to store more energy than electrolytic capacitors maintaining the capability to swap it at high power levels. Firstly, different solution used to connect SCs to a FC based conversion system are considered. Then, a comparison of bi-directional DC/DC converters designed to manage SCs energy is performed. Finally, the converter design and a laboratory prototype of the adopted solution are reported. (authors)

Cacciato, M.; Giulii Capponi, F. [Rome Univ., ' La Sapienza' , Dept. of Electrical Engineering (Italy)

2004-07-01

200

On-chip frequency compensation with a dual signal path operational transconductance amplifier for a voltage mode control DC/DC converter  

International Nuclear Information System (INIS)

A novel on-chip frequency compensation circuit for a voltage-mode control DC/DC converter is presented. By employing an RC network in the two signal paths of an operational transconductance amplifier (OTA), the proposed circuit generates two zeros to realize high closed-loop stability. Meanwhile, full on-chip integration is also achieved due to its simple structure. Hence, the number of off-chip components and the board space is greatly reduced. The structure of the dual signal path OTA is also optimized to help get a better transition response. Implemented in a 0.5 ?m CMOS process, the voltage mode control DC/DC converter with the proposed frequency compensation circuit exhibits good stability. The test results show that both load and line regulations are less than 0.3%, and the output voltage can be recovered within 15 ?s for a 400 mA load step. Moreover, the compensation components area is less than 2% of the die's area and the board space is also reduced by 11%. The efficiency of the whole chip can be up to 95%. (semiconductor integrated circuits)

2012-04-01

 
 
 
 
201

Two-Phase Interleaved Buck Converter with a new Digital Self-Oscillating Modulkator  

DEFF Research Database (Denmark)

This paper presents a new Digital Self-Oscillating Modulator (DiSOM) for DC/DC converters. The DiSOM modulator alllows the digital control algorithm to sample the output voltage at a sampling frequency higher than the converter switching frequency. This enables higher control loop bandwidth than for traditional digital PWM modulators given a certain switching frequency. A synchronised version of the DiSOM modulator is derived for interleaved converters. A prototype interleaved Buck converter for Point of Load applications has been designed and built to test the performance of DiSOM modulator. The DiSOM modulator and a digital control algorithm have been implemented in an FPGA. Experimental results show that the converter has a very fast transient response when a loadstep is applied to the output. For a loadstep of 50% of nominal output current the output voltage overshoot is less than 2.5% of the nominal output voltage and the settling time is just 8 switching periods.

Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.

2007-01-01

202

Impact of the control constraint on a buck converter design based on multi-objective optimization procedure  

Directory of Open Access Journals (Sweden)

Full Text Available The current paper deals with a multi-objective design approach of power converters applied to a DC-DC buck structure. This approch consists on optimizing a preselected power architecture by minimizing a multi-objective function (volume and time response under multi-physic constraints (efficiency, thermal, electromagnetic compatibility and control. This multi-objective optimization allows evaluating the impact of the control aspect on the converter design by considering the control criteria with the same importance as the conventional constraints. The obtained results confirm the influence of the control on the converter design parameters. They help the designer to choose suitable operating points depending on the desired performances in terms of volume and time response while respecting efficiency, junction temperatures and electromagnetic compatibility constraints.

Cherif Larouci

2012-06-01

203

Synthesis of Nonlinear Control of Switching Topologies of Buck-Boost Converter Using Fuzzy Logic on Field Programmable Gate Array (FPGA)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An intelligent fuzzy logic inference pipeline for the control of a dc-dc buck-boost converter was designed and built using a semi-custom VLSI chip. The fuzzy linguistics describing the switching topologies of the converter was mapped into a look-up table that was synthesized into a set of Boolean equations. A VLSI chip–a field programmable gate array (FPGA) was used to implement the Boolean equations. Features include the size of RAM chip independent of number of rules in the knowledge base...

Asumadu, Johnson A.; Vaidhyanathan Jagannathan; Arkhom Chachavalnanont

2010-01-01

204

DC transformer for DC/DC connection in HVDC network  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents the modeling and control of a multilevel DC/DC bidirectional converter suitable for medium voltage and power applications, with a special interest in wind-power applications. The proposed multilevel topology has a modular structure constituted by base DC/DC converter cells. The multilevel converter is consequently based on Dual Active Bridge (DAB). The overall control of the DC/DC converter is achieved by using a nonlinear control based in Lyapunov theory.

Carrizosa, Jimenez; Benchaib, Abdelkrim; Alou, Pedro; Damm, Gilney

2013-01-01

205

Electrochemical treatment of tannery effluent using a battery integrated DC-DC converter and solar PV power supply-An approach towards environment and energy management.  

Science.gov (United States)

Electrochemical oxidation of tannery effluent was carried out in batch, batch recirculation and continuous reactor configurations under different conditions using a battery-integrated DC-DC converter and solar PV power supply. The effect of current density, electrolysis time and fluid flow rate on chemical oxygen demand (COD) removal and energy consumption has been evaluated. The results of batch reactor show that a COD reduction of 80.85% to 96.67% could be obtained. The results showed that after 7 h of operation at a current density of 2.5 A dm(-2) and flow rate of 100 L h(-1) in batch recirculation reactor, the removal of COD is 82.14% and the specific energy consumption was found to be 5.871 kWh (kg COD)(-1) for tannery effluent. In addition, the performance of single pass flow reactors (single and multiple reactors) system of various configurations are analyzed. PMID:24844896

Iyappan, K; Basha, C Ahmed; Saravanathamizhan, R; Vedaraman, N; Tahiyah Nou Shene, C A; Begum, S Nathira

2014-08-24

206

Soft-Switched Dual-Input DC-DC Converter Combining a Boost-Half-Bridge Cell and a Voltage-Fed Full-Bridge Cell  

DEFF Research Database (Denmark)

This paper presents a new zero-voltage-switching (ZVS) isolated dc-dc converter which combines a boost halfbridge (BHB) cell and a full-bridge (FB) cell, so that two different type of power sources, i.e. both current-fed and voltage-fed, can be coupled effectively by the proposed converter for various applications, such as fuel cell and super-capacitor hybrid energy system. By fully using two high frequency transformers and a shared leg of switches, number of the power devices and associated gate driver circuits can be reduced. With phase-shift control, the converter can achieve ZVS turn-on of active switches and zero-current switching (ZCS) turn-off of diodes. In this paper, derivation, analysis and design of the proposed converter are presented. Finally, a 25~50 V input, 300~400 V output prototype with a 600 W nominal power rating is built up and tested to demonstrate the effectiveness of the proposed converter topology.

Zhang, Zhe; Thomsen, Ole Cornelius

2013-01-01

207

A Bi-Directional Isolated DC/DC Converter as a Core Circuit for 3.3-kV/6.6-kV Power Conversion Systems in the Next Generation  

Science.gov (United States)

This paper describes a bi-directional isolated dc/dc converter considered as a core circuit of 3.3-kV/6.6-kV high-power-density power conversion systems in the next generation. The dc/dc converter is intended to use power switching devices based on SiC and/or GaN, which will be available on the market in the near future. A 350-V, 10-kW and 20kHz dc/dc converter is designed, constructed and tested in this paper. It consists of two single-phase full-bridge converters with the latest trench-gate Si-IGBTs and a 20-kHz transformer with a nano-crystalline soft-magnetic material core and litz wires. The transformer plays an essential role in achieving galvanic isolation between the two full-bridge converters. The overall efficiency from the dc-input to dc-output terminals is accurately measured to be as high as 97%, excluding gate drive circuit and control circuit losses from the whole loss. Moreover, loss analysis is carried out to estimate effectiveness in using SiC-based power switching devices. The loss analysis clarifies that the use of SiC-based power devices may bring a significant reduction in conducting and switching losses to the dc/dc converter. As a result, the overall efficiency may reach 99% or higher.

Inoue, Shigenori; Akagi, Hirofumi

208

Comparative Study on  Paralleled vs. Scaled Dc-dc Converters  in High Voltage Gain Applications  

DEFF Research Database (Denmark)

Today power converters are present in many commercial, medical and industrial applications. A lot of them are high power and high current applications. In order to increase power handling capability several transistors or diodes are paralleled often. However such paralleling may lead to converter's performance degradation or switches quick failure. A parallel modular converter built of many paralleled modules may be an interesting alternative, while a modular converter provides well known advantages like scalability, improved reliability and lower cost. This paper investigates possibility of improving an efficiency by intelligent usage of a modular boost converter in a high voltage gain application.

Klimczak, Pawel; Munk-Nielsen, Stig

2008-01-01

209

A NOVEL EFFICIENT SOFT SWITCHED TWO PORTS DC-DC BOOST CONVERTER WITH OPEN LOOP AND CLOSED LOOP CONTROL  

Directory of Open Access Journals (Sweden)

Full Text Available A multiport converter promises cost-effective, flexible and more efficient energy processing by utilizing only a single power stage. Multiport converters, a promising concept for alternative energy systems, have attracted increasing research interest recently. Zero Voltage Switching (ZVS alleviates the switching losses and improves the converter overall efficiency. Zero voltage switching can be achieved with the help of coupled inductor which also regulates the input current during the load disturbances. To reduce the switching losses and henceforth to improve efficiency of converter system, Zero Voltage Switching (ZVS is employed. . This paper presents a two output ports single stage boost converter with ZVS. The proposed multi output port converter with soft switching is simple and efficient. The analysis is carried out for open loop and closed loop control. The simulation results for the same are presented in this paper.

T.NageswaraRao

2012-07-01

210

Digital Linear and Nonlinear Controllers for Buck Converter  

Directory of Open Access Journals (Sweden)

Full Text Available Both linear PID controllers and fuzzy controllers are designed and implemented for a buck converter. Comparison between the two controllers is made in the aspect of design, implementation and experimental results. Design of fuzzy controllers is based on heuristic knowledge of the converter and tuned using trial and error, while the design of linear PID and PI controllers is based on the frequency response of the buck converter. Implementation of linear controllers is quite straightforward, while implementation of fuzzy controllers has its unique issues. A comparison of experimental results indicates that the performance of the fuzzy controller is superior to that of the linear PID and PI controllers. The fuzzy controller is able to achieve faster transient response, has more stable steady-state response, and is more robust under different operating points.

Shyama M

2012-03-01

211

A Low-Cost Soft-Switched DC/DC Converter for Solid-Oxide Fuel Cells  

Energy Technology Data Exchange (ETDEWEB)

A highly efficient DC to DC converter has been developed for low-voltage high-current solid oxide fuel cells. The newly developed 'V6' converter resembles what has been done in internal combustion engine that split into multiple cylinders to increase the output capacity without having to increase individual cell size and to smooth out the torque with interleaving operation. The development was started with topology overview to ensure that all the DC to DC converter circuits were included in the study. Efficiency models for different circuit topologies were established, and computer simulations were performed to determine the best candidate converter circuit. Through design optimization including topology selection, device selection, magnetic component design, thermal design, and digital controller design, a bench prototype rated 5-kW, with 20 to 50V input and 200/400V output was fabricated and tested. Efficiency goal of 97% was proven achievable through hardware experiment. This DC to DC converter was then modified in the later stage to converter 35 to 63 V input and 13.8 V output for automotive charging applications. The complete prototype was tested at Delphi with their solid oxide fuel cell test stand to verify the performance of the modified DC to DC converter. The output was tested up to 3-kW level, and the efficiency exceeded 97.5%. Multiple-phase interleaving operation design was proved to be reliable and ripple free at the output, which is desirable for the battery charging. Overall this is a very successful collaboration project between the SECA Core Technology Team and Industrial Team.

Jason Lai

2009-03-03

212

Soft Computing Module of High Step-Up DC–DC Converter for PV Module using Simulink Environment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Within the photovoltaic (PV) power-generation market, the  PV module has shown obvious growth. However, a high voltage gain converter is essential for the module’s grid connection through a dc–ac inverter. This paper proposes a converter that employs a floating active switch to isolate energy from the PV panel when the ac module is OFF; this particular design protects installers and users from electrical hazards. Without extreme duty ratios and the numerous turns-ratios of a coupled indu...

Vinoth Kumar, K.; Suresh Kumar, S.; Daison Stallon, S.

2012-01-01

213

Soft Computing Module of High Step-Up DC–DC Converter for PV Module using Simulink Environment  

Directory of Open Access Journals (Sweden)

Full Text Available Within the photovoltaic (PV power-generation market, the  PV module has shown obvious growth. However, a high voltage gain converter is essential for the module’s grid connection through a dc–ac inverter. This paper proposes a converter that employs a floating active switch to isolate energy from the PV panel when the ac module is OFF; this particular design protects installers and users from electrical hazards. Without extreme duty ratios and the numerous turns-ratios of a coupled inductor, this converter achieves a high step-up voltage-conversion ratio; the leakage inductor energy of the coupled inductor is efficiently recycled to the load. These features explain the module’s high-efficiency performance. The detailed operating principles and steady-state analyses of continuous, discontinuous, and boundary conduction modes are described. A 15V input voltage, 200V output voltage, and 100W output power prototype circuit of the proposed converter has been implemented; its maximum efficiency is up to 95.3% and full-load efficiency is 92.3%.

K. Vinoth Kumar

2012-12-01

214

Nonlinear Phenomena in Buck-Boost Power Factor Correction Converter  

Directory of Open Access Journals (Sweden)

Full Text Available Buck-Boost Power-Factor-Correction (PFC converter with Average-Current-Model (ACM control is a nonlinear circuit because of the multiplier using and large change in the duty cycle, so its stability analysis must be studied by nonlinear model. In this paper double averaging method is used for describing the model of this converter. By this model we would be able to explain the low frequency dynamics of the system and identify stability boundaries according to circuit parameters and also nonlinear phenomena of this converter are detected.

Mehrnoosh Vatani

2013-01-01

215

?ontrolling of the multiphase pulse DC-DC converter with a boundary-discontinuous mode of functioning  

Directory of Open Access Journals (Sweden)

Full Text Available Control characteristics for power channels of step-up, step-down and inverting types with a boundary-discontinuous operation mode are constructed and analyzed. Requirements to the synchronization and control system for a multiphase pulse converter (MPC are determined. The author proposes and describes the synchronization and control system providing a uniform shift of electric processes in the MPC with a guaranteed absence of continuous mode.

Gunchenko Y. A.

2007-12-01

216

Simulation of High Step-Up DC–DC Converter for Photovoltaic Module Application using MATLAB/SIMULINK  

Directory of Open Access Journals (Sweden)

Full Text Available As per the present scenario lot of power shortages are there in all over the world especially country like India the grid transferring problem is also high. Almost the power from the fossil fuels are becoming so less some of the examples of the fossil fuels are (coal, lignite, oil, and gases.So most of them looking in forward for the power from green or renewable based energies like solar, wind, biomass, tidal etc. Which does not cause any pollution to the environment. In this paper the simulation and analysis of the PV panel and also high efficient boost converter design and simulation is also performed. Even though the solar based systems are renewable based energies when compared to other renewable energies like wind, biomass it does not connect to more number of grid connections. Lot of necessary steps want to be taken one of the main important factor that high efficient boost converter is needed, here in this paper the input voltage to the boost converter is given as 15V and receives the output voltage of 55.64V

S.Daison Stallon

2013-06-01

217

A NEW GENERATION VLSI APPROACH FOR THE PWM CONTROL OF AN INTEGRATED FOUR-PORT DC-DC CONVERTER  

Directory of Open Access Journals (Sweden)

Full Text Available In the recent years, the increase in the petroleum prices, the rapid run out tendency of fossil fuel reserves and their unavoidable harmful effects and political instabilities in the regions of energy sources have been accelerated the studies on the renewable energy systems. Although various renewable energy power generations are in practice today, the most popular is using photovoltaic (PV arrays and wind generators. Since PV and wind sources can meet the required demand but either source alone provides an intermittent supply and energy storage is needed to deliver a reliable supply. However these two sources complement each other. A combined plant (hybrid therefore has higher availability than either individual source and so needs less storage capacity. This paper proposes a novel converter topology that interfaces four power ports: two sources (PVand wind source, one bidirectional storage port, and one isolated load port. Power electronic converter is needed to interface and concurrently control multiple renewable energy sources with the load along with energy storage in stand-alone or grid-connected residential, commercial and automobile applications. The power electronic interface also contains some level of monitoring and control functionality to ensure that the distributed energy system can operate as required. In the proposed scheme, a unique VLSI chip called Digital Signal Controller (DSC is used to implement the controller operation which has the features of both microcontroller and digital signal processor (DSP. In this work, dsPIC30F2010 DSC chip is used to program the phase shift angles and generate the PWM pulses for the converter switches. The results of proposed system are recorded and analyzed. The experimental results have verified the proposed scheme of PWM control. The proposed topology and control is particularly relevant to battery-backed power systems having multiple renewable sources.

SANGAMESH SAKRI

2012-12-01

218

Analysis and Design of Multi Input Dc–Dc Converter for Integrated Wind PV Cell Renewable Energy Generated System  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this paper is to propose amulti-input power converter for the hybrid system in order tosimplify the power system and reduce the cost. The proposedconverter interfaces two unidirectional input ports and abidirectional port for storage element in a unified structure. Italso utilizes four power switches that are controlled independentlywith four different duty ratios. The renewable power systemhybridizes PV and Wind as main source & Battery Power forbackup energy source. Three different power operation modes aredefined for the converter based on utilization state of the battery asfollows: 1 An operation type wherein power is delivered to loadfrom hybrid renewable energy sources; 2A single type whereinonly one renewable energy source supplies power to the load withbattery discharging; 3 An operation type wherein power isdelivered to load from renewable sources along with batterycharging. A simple and cost effective control with DC-DCconverter is used for maximum power point tracking (MPPT andhence maximum power is extracted from the source .Theintegration of the hybrid renewable power system is implementedand simulated using MATLAB/SIMULINK.

S. Ramya

2012-11-01

219

A high voltage DC-DC converter driving a Dielectric Electro Active Polymer actuator for wind turbine flaps  

DEFF Research Database (Denmark)

The Dielectric Electro Active Polymer (DEAP) material is a very thin (~80 μm) silicone elastomer film with a compliant metallic electrode layer on both sides. The DEAP is fundamentally a capacitor that is capable of very high strain. The property that the polymer changes its shape, as a result of the electrostatic forces generated by an applied voltage, can be used in actuators, for instance to adapt the trailing edges of wind turbine blades, for maximum efficiency and increased energy output. Conventional actuator technologies have not proven feasible solutions for driving the wind turbine flaps. With the DEAP based high power actuator, it is expected to make a reliable and light solution with superior controllability. The current DEAP technology requires high DC voltage in the range of kV to fully utilize the DEAP material as an actuator. In this paper we propose a flyback converter topology to obtain high voltage at low current, for driving the DEAP actuator. Simulation and experimental results for uni-directional flyback converter topology are shown.

Thummala, Prasanth; Zhang, Zhe

2012-01-01

220

A Novel Over-Current Protection Technique Applied to Peak-Current Type DC-DC Converter  

Directory of Open Access Journals (Sweden)

Full Text Available The change of the over-current protection point of the power switches, caused by slope compensation, is analyzed in detail. It is discovered that the peak current protecting value increases as the duty cycle decreases. As a result, the safety operation of the switches is damaged greatly. A novel solution to improve over-current protection with constant peak current limitation is proposed by inducing synchronous slope compensation into the current limit function instead of the original constant voltage. The design principle and method of the protection circuit based on a UC3846 PWM controller for the interleaved dual-forward converter is presented. Experimental results are given to verify the analysis.

Yan Xing

2010-06-01

 
 
 
 
221

Battery Management System—Balancing Modularization Based on a Single Switched Capacitor and Bi-Directional DC/DC Converter with the Auxiliary Battery  

Directory of Open Access Journals (Sweden)

Full Text Available Lithium-based batteries are considered as the most advanced batteries technology, which can be designed for high energy or high power storage systems. However, the battery cells are never fully identical due to the fabrication process, surrounding environment factors and differences between the cells tend to grow if no measures are taken. In order to have a high performance battery system, the battery cells should be continuously balanced for maintain the variation between the cells as small as possible. Without an appropriate balancing system, the individual cell voltages will differ over time and battery system capacity will decrease quickly. These issues will limit the electric range of the electric vehicle (EV and some cells will undergo higher stress, whereby the cycle life of these cells will be shorter. Quite a lot of cell balancing/equalization topologies have been previously proposed. These balancing topologies can be categorized into passive and active balancing. Active topologies are categorized according to the active element used for storing the energy such as capacitor and/or inductive component as well as controlling switches or converters. This paper proposes an intelligent battery management system (BMS including a battery pack charging and discharging control with a battery pack thermal management system. The BMS user input/output interfacing. The battery balancing system is based on battery pack modularization architecture. The proposed modularized balancing system has different equalization systems that operate inside and outside the modules. Innovative single switched capacitor (SSC control strategy is proposed to balance between the battery cells in the module (inside module balancing, IMB. Novel utilization of isolated bidirectional DC/DC converter (IBC is proposed to balance between the modules with the aid of the EV auxiliary battery (AB. Finally an experimental step-up has been implemented for the validation of the proposed balancing system.

Mohamed Daowd

2014-04-01

222

DC–DC powering for the CMS pixel upgrade  

International Nuclear Information System (INIS)

The CMS experiment plans to replace its silicon pixel detector with a new one with improved rate capability and an additional detection layer at the end of 2016. In order to cope with the increased number of detector modules the new pixel detector will be powered via DC–DC converters close to the sensitive detector volume. This paper reviews the DC–DC powering scheme and reports on the ongoing R and D program to develop converters for the pixel upgrade. Design choices are discussed and results from the electrical and thermal characterisation of converter prototypes are shown. An emphasis is put on system tests with up to 24 converters. The performance of pixel modules powered by DC–DC converters is compared to conventional powering. The integration of the DC–DC powering scheme into the pixel detector is described and system design issues are reviewed

2013-12-21

223

DC–DC powering for the CMS pixel upgrade  

Energy Technology Data Exchange (ETDEWEB)

The CMS experiment plans to replace its silicon pixel detector with a new one with improved rate capability and an additional detection layer at the end of 2016. In order to cope with the increased number of detector modules the new pixel detector will be powered via DC–DC converters close to the sensitive detector volume. This paper reviews the DC–DC powering scheme and reports on the ongoing R and D program to develop converters for the pixel upgrade. Design choices are discussed and results from the electrical and thermal characterisation of converter prototypes are shown. An emphasis is put on system tests with up to 24 converters. The performance of pixel modules powered by DC–DC converters is compared to conventional powering. The integration of the DC–DC powering scheme into the pixel detector is described and system design issues are reviewed.

Feld, Lutz, E-mail: Lutz.Feld@rwth-aachen.de; Fleck, Martin; Friedrichs, Marcel; Hensch, Richard; Karpinski, Waclaw; Klein, Katja; Rittich, David; Sammet, Jan; Wlochal, Michael

2013-12-21

224

DC-DC Powering for the CMS Pixel Upgrade  

CERN Document Server

The CMS experiment plans to replace its silicon pixel detector with a new one with improved rate capability and an additional detection layer at the end of 2016. In order to cope with the increased number of detector modules the new pixel detector will be powered via DC-DC converters close to the sensitive detector volume. This paper reviews the DC-DC powering scheme and reports on the ongoing R and D program to develop converters for the pixel upgrade. Design choices are discussed and results from the electrical and thermal characterisation of converter prototypes are shown. An emphasis is put on system tests with up to24 converters. The performance of pixel modules powered by DC-DC converters is compared to conventional powering. The integration of the DC-DC powering scheme into the pixel detector is described and system design issues are reviewed.

Feld, Lutz Werner; Marcel Friedrichs; Richard Hensch; Karpinski, Waclaw; Klein, Katja; Rittich, David Michael; Sammet, Jan Domenik; Wlochal, Michael

2013-01-01

225

Synthesis of Nonlinear Control of Switching Topologies of Buck-Boost Converter Using Fuzzy Logic on Field Programmable Gate Array (FPGA  

Directory of Open Access Journals (Sweden)

Full Text Available An intelligent fuzzy logic inference pipeline for the control of a dc-dc buck-boost converter was designed and built using a semi-custom VLSI chip. The fuzzy linguistics describing the switching topologies of the converter was mapped into a look-up table that was synthesized into a set of Boolean equations. A VLSI chip–a field programmable gate array (FPGA was used to implement the Boolean equations. Features include the size of RAM chip independent of number of rules in the knowledge base, on-chip fuzzification and defuzzification, faster response with speeds over giga fuzzy logic inferences per sec (FLIPS, and an inexpensive VLSI chip. The key application areas are: 1 on-chip integrated controllers; and 2 on-chip co-integration for entire system of sensors, circuits, controllers, and detectors for building complete instrument systems.

Vaidhyanathan Jagannathan

2010-03-01

226

Integrated design & control of a buck boost converter  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english This paper presents the integrated design and control of a buck boost converter (BBC). In the proposed methodology the design tool provides simultaneously the controller tuning and BBC design parameters in such a way that some closed-loop pre-specified static and dynamic behavior is obtained. This a [...] pproach contrasts with the traditional methodology, where the design of BBC is performed without taking into account its dynamical behavior. An optimization procedure is used to obtain the electronic components of the BBC and the tuning parameters of the controller, minimizing an objective function that considers the set of performance specifications. Although the methodology can be applied to any converter and any control strategy, in this particular case an ideal BBC and a Sliding Model Control (SMC) strategy are used. Some simulation results show the advantages and principally the flexibility that can be obtained with this approach.

Garcia, Martin J. Pomar; Normey-Rico, Julio E.; Gutierrez, Gloria; Prada, César de.

227

Dynamical analysis and experimental verification of valley current controlled buck converter  

International Nuclear Information System (INIS)

The dynamical behaviours of valley current controlled buck converter are studied by establishing its corresponding discrete iterative map model in this paper. Time-domain waveforms and phase portraits of valley current controlled buck converter are obtained by Runge–Kutta algorithm through a piecewise smooth switching model. The research results indicate that the valley current controlled buck converter exhibits rich nonlinear phenomena, and it has routes to chaos through period-doubling bifurcation and border-collision bifurcation in a wide parameter range. Interesting inverse nonlinear behaviours compared with peak current controlled buck converter are observed in the valley current controlled buck converter. Analysis and simulation results are verified by experimental results. (general)

2010-05-01

228

A 1500 mA, 10 MHz on-time controlled buck converter with ripple compensation and efficiency optimization  

International Nuclear Information System (INIS)

A 1500 mA, 10 MHz self-adaptive on-time (SOT) controlled buck DC—DC converter is presented. Both a low-cost ripple compensation scheme (RCS) and a self-adaptive on-time generator (SAOTG) are proposed to solve the system stability and frequency variation problem. Meanwhile a self-adaptive power transistor sizing (SAPTS) technique is used to optimize the efficiency especially with a heavy load. The circuit is implemented in a 2P4M 0.35 ?m CMOS process. A small external inductor of 0.47 ?H and a capacitor of 4.7 ?F are used to lower the cost of the converter and keep the output ripple to less than 10 mV. The measurement results show that the overshoot of the load transient response is 8 mV at 200 mA step and the dynamic voltage scaling (DVS) performance is a rise of 16 ?s/V and a fall of 20 ?s/V. With a SAPTS technique and PFM control, the efficiency is maintained at more than 81% for a load range of 20 to 1500 mA and the peak efficiency reaches 88.43%. (semiconductor integrated circuits)

2012-01-01

229

A 1500 mA, 10 MHz on-time controlled buck converter with ripple compensation and efficiency optimization  

Science.gov (United States)

A 1500 mA, 10 MHz self-adaptive on-time (SOT) controlled buck DC—DC converter is presented. Both a low-cost ripple compensation scheme (RCS) and a self-adaptive on-time generator (SAOTG) are proposed to solve the system stability and frequency variation problem. Meanwhile a self-adaptive power transistor sizing (SAPTS) technique is used to optimize the efficiency especially with a heavy load. The circuit is implemented in a 2P4M 0.35 ?m CMOS process. A small external inductor of 0.47 ?H and a capacitor of 4.7 ?F are used to lower the cost of the converter and keep the output ripple to less than 10 mV. The measurement results show that the overshoot of the load transient response is 8 mV @ 200 mA step and the dynamic voltage scaling (DVS) performance is a rise of 16 ?s/V and a fall of 20 ?s/V. With a SAPTS technique and PFM control, the efficiency is maintained at more than 81% for a load range of 20 to 1500 mA and the peak efficiency reaches 88.43%.

Jiale, Yu; Danzhu, Lü; Zhiliang, Hong

2012-01-01

230

A ripple-mitigating pre-amplifier based on interleaved DC-DC boost converters for efficiency improvement / Pre-Amplificador de potencia basado en conexión paralela de convertidores DC-DC para reducción de rizados de corriente e incremento de eficiencia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish Este artículo propone un pre-amplificador basado en convertidores DC-DC conectados en paralelo para la reducción de armónicos inyectados a fuentes de potencia. Las principales características del pre-amplificador son la reducción del rizado de corriente de entrada en convertidores de potencia, incre [...] mentado además la eficiencia del sistema de conversión. Se describe el cálculo de las condiciones óptimas de operación del pre-amplificador, así como su modelado matemático y control para operar en las condiciones seleccionadas. Así mismo, se analiza el pre-amplificador con un convertidor elevador clásico, obteniendo una reducción significativa en el rizado de corriente inyectado a la fuente, así como un incremento en la eficiencia del sistema. Finalmente, los análisis teóricos se confirman a través de simulaciones circuitales y resultados experimentales. Abstract in english An efficient pre-amplifier based on interleaved DC-DC boost switching converters to mitigate high-frequency harmonics injection to power sources is proposed. The main features of the pre-amplifier are mitigate the ripple of power converters input-current and improving the efficiency of the whole pow [...] er conversion chain. The pre-amplifier optimal operating conditions are calculated, and the circuit is modeled and controlled to operate in such conditions. The pre-amplifier interacting with a classical single boost is analyzed, obtaining a strong reduction in the current ripple injected to the source, and also improving the efficiency of the initial conversion system. Finally, the theoretical analyses are confirmed by means of circuital PSIM simulations and experimental results.

Eliana, Arango; Carlos, Ramos-Paja; Carlos, Carrejo; Roberto, Giral; Andres, Saavedra-Montes.

231

DESIGN AND COMPARATIVE ANALYSIS OF DC-DC BOOST AND SINGLE-ENDED PRIMARY-INDUCTANCE CONVERTER CONVERTERS USING SOLAR POWERED MAXIMUM POWER POINT TRACKING ALGORITHMS  

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Full Text Available This study provides a comprehensive review of the Maximum Power Point Tracking (MPPT techniques applied to Photovoltaic (PV power system. Also this study presents a comparative study between three most fashionable techniques such as Incremental conductance (Inc algorithm and Perturb and Observation (P&O algorithm and fuzzy logic controller. These three techniques have been applied to converters such as Boost and SEPIC for analyzing the performance in various climatic conditions of PV. The analysis of each technique with converters has been carried out by using MATLAB/simulink software. From the results few comparisons has been made and found that the boost converter with Incremental conductance algorithmic technique offered best and optimum results when compared with other techniques. This PV system can supply the maximum power to the load at all times due to which the entire PV system operates with maximum efficiency and produces its maximum power.

C. Thulasiyammal

2014-01-01

232

Design Considerations for High Step-Down ratio Buck Regulators  

CERN Document Server

The buck or step-down DC-DC converter is the workhorse switching power supply topology. It utilizes two switches (two FETS or one FET and one diode) along with an output inductor and output capacitor. Whether you look at a large computer server, a personal desktop or a laptop computer, a cell phone or a GPS unit all will contain a buck converter in one form or another. This paper will discuss the synchronous buck topology, design considerations, component selection followed by a small signal model of buck converter. Issues that are important in optimizing the efficiency of the design for example MOSFET selection, the impact that the MOSFET driver plays in improving the efficiency will be examined. The paper will finish by contrasting various control architectures.

Khanna, R

2008-01-01

233

Commercial Buck Converters and Custom Coil Development for the ATLAS Inner Detector Upgrade  

Energy Technology Data Exchange (ETDEWEB)

A new generation of higher gain commercial buck converters built using advanced short channel CMOS processes has the potential to operate in the Atlas Inner Detector at the Super Large Hadron Collider (sLHC). This approach would inherently be more efficient than the existing practice of locating the power conversion external to the detector. The converters must operate in a large magnetic field and be able to survive both high doses of ionizing radiation and large neutron fluences. The presence of a large magnetic field necessitates the use of an air core inductor which is developed and discussed here. Noise measurements will be made to investigate the effect of the high frequency switching of the buck converter on the sensitive front end electronics. Radiation hardness of selected buck converters and mosfets will also be reported.

Dhawan, S.; Lanni, F.; Baker, O.; Chen, H.; Khanna, R.; Kierstead, J.; Lynn, D.; Musso, C.; Rescia, S.; Smith, H.; Tipton, P. and Weber, M.

2010-04-01

234

Transfer function modeling and analysis of the open-loop Buck converter using the fractional calculus  

Science.gov (United States)

Based on the fact that the real inductor and the real capacitor are fractional order in nature and the fractional calculus, the transfer function modeling and analysis of the open-loop Buck converter in a continuous conduction mode (CCM) operation are carried out in this paper. The fractional order small signal model and the corresponding equivalent circuit of the open-loop Buck converter in a CCM operation are presented. The transfer functions from the input voltage to the output voltage, from the input voltage to the inductor current, from the duty cycle to the output voltage, from the duty cycle to the inductor current, and the output impedance of the open-loop Buck converter in CCM operation are derived, and their bode diagrams and step responses are calculated, respectively. It is found that all the derived fractional order transfer functions of the system are influenced by the fractional orders of the inductor and the capacitor. Finally, the realization of the fractional order inductor and the fractional order capacitor is designed, and the corresponding PSIM circuit simulation results of the open-loop Buck converter in CCM operation are given to confirm the correctness of the derivations and the theoretical analysis.

Wang, Fa-Qiang; Ma, Xi-Kui

2013-03-01

235

On the Suitability of Interleaved Switched Capacitor Converter as an Interface for Electric Vehicle Dual Energy Storage Systems  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the analysis and novel hybrid controller design for an interleaved 2-quadrant switched capacitor (SC) bidirectional DC/DC converter for a hybrid electric vehicle (HEV) dual energy storage system. The designed novel control strategy enables simpler dynamics compared to a standard buck converter with input filter, good regulation capability, low EMI, lower source current ripple, ease of control, and continuous input current waveform in both buck as well as boost modes of operation.

Amjadi, Zahra; Williamson, Sheldon

2010-09-15

236

Advanced buck converter power supply ABCPS for APT  

International Nuclear Information System (INIS)

The United States Department of Energy (DOE) is planning to fabricate an Accelerator for the Production of Tritium (APT) at their Savannah River Site, to provide Tritium for national defense. The 1700 million electron volt (MeV) proton beam accelerator will be powered by radio frequency (RF) klystrons. A direct current (DC) power supply is required for each of the approximately two hundred and fifty 1-megawatt (MW) continuous wave klystrons in the RF power system. The requirements are that the power supply meet output performance specifications, provide fault protection for the klystron, have high efficiency, high reliability, good maintainability, and be readily manufacturable. As the power supplies are one of the largest cost elements in the accelerator, a technology review was made to determine the most economical approach to satisfy the requirements. A switch-mode power supply employing a buck-regulator was identified as being potentially the lowest cost approach. As the switch represents a certain development risk, a small-scale prototype has been constructed for evaluation, and has resulted in the decision to fabricate a full-scale prototype power supply. A description of the hardware will be presented

1998-08-23

237

Advanced buck converter power supply ABCPS for APT  

Energy Technology Data Exchange (ETDEWEB)

The United States Department of Energy (DOE) is planning to fabricate an Accelerator for the Production of Tritium (APT) at their Savannah River Site, to provide Tritium for national defense. The 1700 million electron volt (MeV) proton beam accelerator will be powered by radio frequency (RF) klystrons. A direct current (DC) power supply is required for each of the approximately two hundred and fifty 1-megawatt (MW) continuous wave klystrons in the RF power system. The requirements are that the power supply meet output performance specifications, provide fault protection for the klystron, have high efficiency, high reliability, good maintainability, and be readily manufacturable. As the power supplies are one of the largest cost elements in the accelerator, a technology review was made to determine the most economical approach to satisfy the requirements. A switch-mode power supply employing a buck-regulator was identified as being potentially the lowest cost approach. As the switch represents a certain development risk, a small-scale prototype has been constructed for evaluation, and has resulted in the decision to fabricate a full-scale prototype power supply. A description of the hardware will be presented.

Street, R.; Overett, T.; Bowles, E. [General Atomics, San Diego, CA (United States)

1998-12-31

238

Modelling and Simulation of Closed Loop Controlled Buck Converter Fed Pmbldc Drive System  

Directory of Open Access Journals (Sweden)

Full Text Available Permanent Magnet Brushless DC Motor (PMBLDC is one of the best electrical drives that has increasing popularity, due to their high efficiency, reliability, good dynamic response and very low maintenance. This makes the interest of modeling an ideal PMBLDC motor and it’s associated Drive System in simple and lucid manner. In this paper the drive system is proposed with a buck converter topology. It has the advantages of reduced switching losses, low inductor power loss, reduced ripple by using a pi-filter, which in turn makes the DC link voltage to be stable. The modeling and simulation of the PMBLDC motor is done using the software package MATLAB/SIMULINK. The operation principle of the buck converter is analyzed and the simulation results are presented in this paper to verify the theoretical analysis.

R. Dhanasekaran

2011-04-01

239

Design and simulation of fuzzy controlled quasi resonant buck converter  

Directory of Open Access Journals (Sweden)

Full Text Available A controller based on Fuzzy logic is implemented and its application to the regulation of power converter is investigated. Being free of complex equations and heavy computation, it achieves fast dynamic response and adapts to varying conditions of operation. The topology is modeled using MATLAB software and operated at finite higher switching frequency to evaluate its closed-loop performance in respect of line and load regulation. It is verified by transient characteristics that due to quasi-resonance there is a drastic change in peak overshoot and settling time and the proposed strategy has good rejection ability for supply and load disturbances.

A. Rameshkumar

2009-07-01

240

A New Buck-Boost Converter for a Hybrid-Electric Drive Stand  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes work on the laboratory working stand for a hybrid-electric drive located in laboratory T2:H1-26.The basic idea is to operate the combustion engine in its optimal regime. In this regime the engine has the highest efficiency and minimal smoke exhaust. This optimal regime is only a small portion of its operation area. Because the engine has to operate in this area, it is necessary to add a new converter to the hybrid-electric stand. The new converter must be allowed to buck and boost and must operate as a current source in this regime. 

P. Mašek

2009-01-01

 
 
 
 
241

Modeling and dynamics analysis of the fractional-order Buck—Boost converter in continuous conduction mode  

Science.gov (United States)

In this paper, the fractional-order mathematical model and the fractional-order state-space averaging model of the Buck—Boost converter in continuous conduction mode (CCM) are established based on the fractional calculus and the Adomian decomposition method. Some dynamical properties of the current-mode controlled fractional-order Buck—Boost converter are analysed. The simulation is accomplished by using SIMULINK. Numerical simulations are presented to verify the analytical results and we find that bifurcation points will be moved backward as ? and ? vary. At the same time, the simulation results show that the converter goes through different routes to chaos.

Yang, Ning-Ning; Liu, Chong-Xin; Wu, Chao-Jun

2012-08-01

242

Modeling and dynamics analysis of the fractional-order Buck—Boost converter in continuous conduction mode  

International Nuclear Information System (INIS)

In this paper, the fractional-order mathematical model and the fractional-order state-space averaging model of the Buck—Boost converter in continuous conduction mode (CCM) are established based on the fractional calculus and the Adomian decomposition method. Some dynamical properties of the current-mode controlled fractional-order Buck—Boost converter are analysed. The simulation is accomplished by using SIMULINK. Numerical simulations are presented to verify the analytical results and we find that bifurcation points will be moved backward as ? and ? vary. At the same time, the simulation results show that the converter goes through different routes to chaos. (general)

2012-08-01

243

A High Step-Down Interleaved Buck Converter with Active-Clamp Circuits for Wind Turbines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, a high step-down interleaved buck coupled-inductor converter (IBCC) with active-clamp circuits for wind energy conversion has been studied. In high step-down voltage applications, an IBCC can extend duty ratio and reduce voltage stresses on active switches. In order to reduce switching losses of active switches to improve conversion efficiency, a IBCC with soft-switching techniques is usually required. Compared with passive-clamp circuits, the IBCC with active-clamp circuits ha...

Cheng-Tao Tsai; Chih-Lung Shen

2012-01-01

244

Design and Analysis of PI like Fuzzy Logic Controlled Buck Converter  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a novel design of Proportional and Integral (PI - like Fuzzy Logic Controller (FLC for Buck converters that integrates linear control techniques with Fuzzy Logic .The design procedure allows the small signal model of the converter and linear control design techniques to be used in the initial stages of FLC design. This simplifies the small signal design and stability assessment of the FLC.By exploiting the Fuzzy Logic structure of the controller, heuristic knowledge is incorporated in the design, which results in a nonlinear controller with improved Performance over linear PI controllers. The major advantage of the proposed design method for FLC is that compared to other methods is trial and error effort in the design is greatly reduced. MATLAB/SIMULINK is used for implementation and results shows the performance of the converter.

M.SIVA RAMA KRISHNA

2013-06-01

245

Steady-state analysis of dead-time effect on bidirectional buck converters  

DEFF Research Database (Denmark)

Half-bridge inverters, full-bridge inverters and bidirectional buck converters share a common topological structure, in which two switches and two diodes are present. In such a topology, a dead time between the two signals controlling the switches is inserted. This influences the relationship between output voltage, input voltage and duty cycle as a function of the output current. In the literature, the dead-time effect has been studied in relation with inverters, active filters, voltage regulated modules and high-precision power amplifiers, and dead-time compensation techniques have been proposed. However, the measurement of the current is normally required for all dead-time compensation strategies, which can be a problem when the current approaches or crosses zero. In this paper, the operation of a bidirectional buck converter in the region around zero current has been analytically analyzed. It has been shown that in a region around zero there is no dead-time effect. The analytical expression of the bordersbetween the areas where the dead-time effect is positive, zero or negative has been given. Moreover it has been shown that between these three areas, there are four other transitional areas. The analytical analysis has been confirmed by simulation and experimental results.

Bidoggia, Benoit; Maheshwari, Ram Krishan

2012-01-01

246

Maximum Power Point Tracking For Photovoltaic System by Perturb and Observe Method Using Buck Boost Converter  

Directory of Open Access Journals (Sweden)

Full Text Available Energy, especially alternative source of energy is vital for the development of a country. In future, the world anticipates to develop more of its solar resource potential as an alternative energy source to overcome the persistent shortages and unreliability of power supply. In order to maximize the power output the system components of the photovoltaic system should be optimized. For the optimization maximum power point tracking (MPPT is a promising technique that grid tie inverters, solar battery chargers and similar devices use to get the maximum possible power from one or more solar panels. Among the different methods used to track the maximum power point, Perturb and Observe method is a type of strategy to optimize the power output of an array. In this method, the controller adjusts the voltage by a small amount from the array and measures power, if the power increases, further adjustments in that direction are tried until power no longer increases. In this research paper the system performance is optimized by perturb and observe method using buck boost converter. By varying the duty cycle of the buck boost converter, the source impedance can be matched to adjust the load impedance to improve the efficiency of the system. The Performance has been studied by the MATLAB/Simulink.

M.S.SIVAGAMAUNDARI, DR.P.MELBA MARY, V.K.VELVIZHI

2013-06-01

247

Performance Comparison of Various Control Algorithms for an Asynchronous Buck Converter  

Directory of Open Access Journals (Sweden)

Full Text Available The control of power electronic circuits is a challenging field of research due to the requirements imposed by the applications. A controller design for a Buck converter which steps down a given dc value to a desired regulated dc value is the system taken into consideration in this study. The controller designed for Buck converter has to control rise time, peak overshoot, settling time, bandwidth which are affected by the load and line variations. Quarter Amplitude Decay (QAD, Internal Model Control (IMC and Pole placement techniques are used to obtain the parameters of the PID controller. The performances of these tuning procedures are evaluated and the comparison is tabulated. It is found that the controller tuned by pole placement method gives less rise time and settling time with negligible overshoot. But transfer function of pole-placement base controller is quite complex and has high number coefficients which is difficult to realize in real time systems. QAD based PID controller has less rise time and settling time but it has peak over shoot which will produce voltage spikes in real time systems. Hence an IMC based PID controller which has acceptable rise time and settling time with no peak overshoot is realized in real form by using operational amplifiers. The performance is evaluated and tabulated under varying load and reference voltage conditions.

S. AugustiLindiya

2014-01-01

248

Performance Analysis of Trench Power MOSFETs in High-Frequency Synchronous Buck Converter Applications  

Directory of Open Access Journals (Sweden)

Full Text Available This paper investigates the performance perspectives and theoretical limitations of trench power MOSFETs in synchronous rectifier buck converters operating in the MHz frequency range. Several trench MOSFET technologies are studied using a mixed-mode device/circuit modeling approach. Individual power loss contributions from the control and synchronous MOSFETs, and their dependence on switching frequency between 500 kHz and 5 MHz are discussed in detail. It is observed that the conduction loss contribution decreases from 40% to 4% while the switching loss contribution increases from 60% to 96% as the switching frequency increases from 500 KHz to 5 MHz. Beyond 1 MHz frequency there is no obvious benefit to increase the die size of either SyncFET or CtrlFET. The RDS(ON×QG figure of merit (FOM still correlates well to the overall converter efficiency in the MHz frequency range. The efficiency of the hard switching buck topology is limited to 80% at 2 MHz and 65% at 5 MHz even with the most advanced trench MOSFET technologies.

Xu Cheng

2008-06-01

249

A Tapped-Inductor Buck-Boost Converter for a Dielectric ElectroActive Polymer Generator  

DEFF Research Database (Denmark)

Energy harvesting applications based on Dielectric ElectroActive Polymer (DEAP) generators have been in the spotlight in recent years after the latter onesâ?? documented advantages against competing electromagnetic and field-activated technologies. Yet, the need for bidirectional energy flow under high step-up and high step-down voltage conversion ratios, accompanied by low-average but relatively high-peak currents, imposes great challenges on the design of the employed power electronic converter. In addition, the effective operational range of the converter is usually limited by the lack of commercially-available, high-efficient, high-voltage, low-power semiconductor devices. In this paper, a high-efficient bidirectional tapped-inductor buck-boost converter, addressing high step-up and high step-down voltage conversion ratios, is proposed for energy harvesting applications based on DEAP generators. The high-side switch of the converter is replaced by a string of three non-matched, non-thermally-coupled, off-the-shelf MOSFETs, extending its effective operational range. Experiments conducted on a standalone DEAP generator validate the applicability of the proposed converter by demonstrating energy harvesting of 0.42 J, at 0.75 Hz and 60 % delta-strain, characterized by a world-first; energy density equal to 2 J per kg of active material.

Dimopoulos, Emmanouil; Munk-Nielsen, Stig

2014-01-01

250

Theoretical assessment of the maximum power point tracking efficiency of photovoltaic facilities with different converter topologies  

Energy Technology Data Exchange (ETDEWEB)

The operating point of a photovoltaic generator that is connected to a load is determined by the intersection point of its characteristic curves. In general, this point is not the same as the generator's maximum power point. This difference means losses in the system performance. DC/DC converters together with maximum power point tracking systems (MPPT) are used to avoid these losses. Different algorithms have been proposed for maximum power point tracking. Nevertheless, the choice of the configuration of the right converter has not been studied so widely, although this choice, as demonstrated in this work, has an important influence in the optimum performance of the photovoltaic system. In this article, we conduct a study of the three basic topologies of DC/DC converters with resistive load connected to photovoltaic modules. This article demonstrates that there is a limitation in the system's performance according to the type of converter used. Two fundamental conclusions are derived from this study: (1) the buck-boost DC/DC converter topology is the only one which allows the follow-up of the PV module maximum power point regardless of temperature, irradiance and connected load and (2) the connection of a buck-boost DC/DC converter in a photovoltaic facility to the panel output could be a good practice to improve performance. (author)

Enrique, J.M.; Duran, E.; Andujar, J.M. [Departamento de Ingenieria Electronica, de Sistemas Informaticos y Automatica, Universidad de Huelva (Spain); Sidrach-de-Cardona, M. [Departamento de Fisica Aplicada, II, Universidad de Malaga (Spain)

2007-01-15

251

Monolithic quasi-sliding-mode controller for SIDO buck converter with a self-adaptive free-wheeling current level  

International Nuclear Information System (INIS)

An analog implementation of a novel fixed-frequency quasi-sliding-mode controller for single-inductor dual-output (SIDO) buck converter in pseudo-continuous conduction mode (PCCM) with a self-adaptive freewheeling current level (SFCL) is presented. Both small and large signal variations around the operation point are considered to achieve better transient response so as to reduce the cross-regulation of this SIDO buck converter. Moreover, an internal integral loop is added to suppress the steady-state regulation error introduced by conventional PWM-based sliding mode controllers. Instead of keeping it as a constant value, the free-wheeling current level varies according to the load condition to maintain high power efficiency and less cross-regulation at the same time. To verify the feasibility of the proposed controller, an SIDO buck converter with two regulated output voltages, 1.8 V and 3.3 V, is designed and fabricated in HEJIAN 0.35 ?m CMOS process. Simulation and experiment results show that the transient time of this SIDO buck converter drops to 10 ?s while the cross-regulation is reduced to 0.057 mV/mA, when its first load changes from 50 to 100 mA. (semiconductor integrated circuits)

2013-01-01

252

Development of a state feedback controller for the synchronouns buck converter  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english A digital control algorithm for a current-mode (CM) and a voltage-mode (VM) synchronous buck converter (SBC) is developed. In both cases, the design leads to a stable controller, even for a duty cycle larger than 50%. The desired output voltage and the transient response can be independently specifi [...] ed. Moreover, zero steady-state error in the output voltage can be obtained with the aid of additional dynamics. In both cases, the specification is done by pole placement using complete state feedback. A discrete-time model is used to design the feedback gains. Both the stability and the small-signal transient response are analyzed. In another paper (Oliva et al., 2003) the control algorithms are experimentally validated with a DSP-controlled SBC.

Oliva, A.; Chiacchiarini, H.; Bortolotto, G..

253

Exploration of Charge Recycling DC-DC Conversion Using a Switched Capacitor Regulator  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The increasing popularity of DVFS (dynamic voltage frequency scaling) schemes for portable low power applications demands highly efficient on-chip DC-DC converters. The primary aim of this work is to enable increased efficiency of on-chip DC-DC conversion for near-threshold operation of multicore chips. The idea is to supply nominal (high) off-chip voltage to the cores which are then “voltage-stacked” to generate the near-threshold (low) voltages based on Kirchhoff’s voltage law through...

Kaushik Mazumdar; Stan, Mircea R.

2013-01-01

254

Mode shift and stability control of a current mode controlled buck-boost converter operating in discontinuous conduction mode with ramp compensation  

International Nuclear Information System (INIS)

By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter, this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in discontinuous conduction mode with a ramp compensation current. With the bifurcation diagram, Lyapunov exponent spectrum, time-domain waveform and parameter space map, the performance of the buck-boost converter circuit utilizing a compensating ramp current has been analysed. The obtained results indicate that the system trajectory is weakly chaotic and strongly intermittent under discontinuous conduction mode. By using ramp compensation, the buck-boost converter can shift from discontinuous conduction mode to continuous conduction mode, and effectively operates in the stable period-one region. (general)

2009-11-01

255

A High Step-Down Interleaved Buck Converter with Active-Clamp Circuits for Wind Turbines  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a high step-down interleaved buck coupled-inductor converter (IBCC with active-clamp circuits for wind energy conversion has been studied. In high step-down voltage applications, an IBCC can extend duty ratio and reduce voltage stresses on active switches. In order to reduce switching losses of active switches to improve conversion efficiency, a IBCC with soft-switching techniques is usually required. Compared with passive-clamp circuits, the IBCC with active-clamp circuits have lower switching losses and minimum ringing voltage of the active switches. Thus, the proposed IBCC with active-clamp circuits for wind energy conversion can significantly increase conversion efficiency. Finally, a 240 W prototype of the proposed IBCC with active-clamp circuits was built and implemented. Experimental results have shown that efficiency can reach as high as 91%. The proposed IBCC with active-clamp circuits is presented in high step-down voltage applications to verify the performance and the feasibility for energy conversion of wind turbines.

Chih-Lung Shen

2012-12-01

256

Buck-boost converter for simultaneous semi-active vibration control and energy harvesting for electromagnetic regenerative shock absorber  

Science.gov (United States)

Regenerative semi-active suspensions can capture the previously dissipated vibration energy and convert it to usable electrical energy for powering on-board electronic devices, while achieve both the better ride comfort and improved road handling performance at the same time when certain control is applied. To achieve this objective, the power electronics interface circuit connecting the energy harvester and the electrical loads, which can perform simultaneous vibration control and energy harvesting function is in need. This paper utilized a buck-boost converter for simultaneous semi-active vibration control and energy harvesting with electromagnetic regenerative shock absorber, which utilizes a rotational generator to converter the vibration energy to electricity. It has been found that when the circuit works in discontinuous current mode (DCM), the ratio between the input voltage and current is only related to the duty cycle of the switch pulse width modulation signal. Using this property, the buck-boost converter can be used to perform semi-active vibration control by controlling the load connected between the terminals of the generator in the electromagnetic shock absorber. While performing the vibration control, the circuit always draw current from the shock absorber and the suspension remain dissipative, and the shock absorber takes no additional energy to perform the vibration control. The working principle and dynamics of the circuit has been analyzed and simulations were performed to validate the concept.

Li, Peng; Zhang, Chongxiao; Kim, Junyoung; Yu, Liangyao; Zuo, Lei

2014-04-01

257

Integrated module inverter using a zeta DC-DC converter with feedforward MPPT (Maximum Power Point Tracking) control; Inversor modulo integrado utilizando um conversor CC-CC zeta com controle MPPT feedforward  

Energy Technology Data Exchange (ETDEWEB)

This work presents the study and development of a processing power system that could be used in the connection of renewable energy sources to commercial power grid. The system consists of a ZETA converter associated with a bridge inverter operating at low frequency. The Zeta converter, operating in discontinuous conduction mode (DCM), plays the main role in this arrangement, producing a rectified sinusoidal current waveform synchronized with the electric grid. The function of the full-bridge inverter, connected in cascade with the Zeta converter, is to reverse every 180 deg the current generated by the Zeta converter. Initially it presents the analysis of the Zeta converter operating in DCM, as well as a design criterion. Following by the control strategy and the experimental results for the proposed system are presented and discussed. (author)

Lopez, Henrique Fioravanti Miguel

2009-08-15

258

Parasitic Effects on the Performance of DC-DC SEPIC in Photovoltaic Maximum Power Point Tracking Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents an analysis of the effect of parasitic resistances on the performance of DC-DC Single Ended Pri- mary Inductor Converter (SEPIC) in photovoltaic maximum power point tracking (MPPT) applications. The energy storage elements incorporated in the SEPIC converter possess parasitic resistances. Although ideal components significantly si...

Nur Mohammad; Muhammad Quamruzzaman; Mohammad Rubaiyat Tanvir Hossain; Mohammad Rafiqul Alam

2013-01-01

259

Adaptive Fuzzy Control of a Fuel Cell/DC-DC Convertor System  

Directory of Open Access Journals (Sweden)

Full Text Available Maintaining a fuel cell system in a correct operating status requires good system control. An adaptive fuzzy control scheme is proposed in this study for the fuel cell/DC-DC converter system to realize constant voltage output under different loads. PID controller and fuzzy controller are used to compare with the proposed adaptive fuzzy controller. Simulation results show that the adaptive fuzzy controller can provide attractive control effects such as faster response characteristic and better steady-state behavior.

Fan Li-Ping

2013-01-01

260

DC-DC Conversion Powering Schemes for the CMS Tracker Upgrade  

CERN Document Server

The CMS experiment foresees upgrades of its silicon pixel and strip detectors for the luminosity upgrade of the Large Hadron Collider (LHC), CERN. Due to an increase in the number of readout channels and higher complexity, larger currents will have to be provided to the detector. Since cable channels are difficult to access and space for cables is limited, this would lead to excessively large resistive power losses in the supply cables, which increase with the current squared. CMS has therefore chosen a novel powering scheme based on DC-DC converters, which allows power to be delivered at a higher voltage and consequently lower current. The development of low-mass, low-noise DC-DC converters for application in CMS is presented, including studies of switching noise, magnetic emissions and power efficiency as well as system tests with silicon strip and pixel modules. A scheme for the integration of DC-DC converters in the silicon pixel detector, currently foreseen to be exchanged around 2016, will be discussed.

Feld, Lutz; Klein, Katja; Merz, Jennifer; Sammet, Jan; Wlochal,Michael

2011-01-01

 
 
 
 
261

Full-bridge type electric converter study using the ZVS-PWM-GEPAE commutation auxiliary cell; Estudo do conversor DC/DC do tipo full-bridge empregando a celula auxiliar de comutacao ZVS-PWM-GEPAE  

Energy Technology Data Exchange (ETDEWEB)

This work presents the analysis and design procedures of a new D C-D C Full Bridge PWM converter, using the ZVS-PWM-GEPAE commutation cell to achieve soft switching. Experimental results obtained from a laboratory prototype rated 1500 W area also presented. It is demonstrated that the inclusion of the auxiliary switches do not modify the PWM switching pattern. Bench tests on the prototype confirm that the proposed circuit exhibits high efficiency and behaves as a constant voltage source over an extended power output range. (author)

Castaldo, Fernando Cardoso

1994-07-01

262

A tapped-inductor buck-boost converter for a multi-DEAP generator energy harvesting system  

DEFF Research Database (Denmark)

Interest on Dielectric ElectroActive Polymer (DEAP) generators has aroused among scientists in recent years, due to the former ones' documented advantages against competing electromagnetic and field-activated technologies. Yet, the need for bidirectional energy flow under high step-up and high step-down voltage conversion ratios, accompanied by low-average but relatively high-peak currents, imposes great challenges on the design of the employed power electronic converter. On top of that, the shortage of commercially-available, high-efficient, high-voltage, low-power semiconductor devices limits the effective operational range of the power electronic converter. In this paper, a bidirectional tapped-inductor buck-boost converter is proposed, addressing high-efficient high step-up and high step-down voltage conversion ratios, for energy harvesting applications based on DEAP generators. The effective operational range of the converter is extended, by replacing its high-side switch with a string of three serialized MOSFETs, to accommodate the need for high-efficient high-voltage operation. Experiments conducted on a single DEAP generator - part of a quadruple DEAP generator energy harvesting system with all elements installed sequentially in the same circular disk with a 90 phase shift - validate the applicability of the proposed converter, demonstrating energy harvesting of 0.26 J, at 0.5 Hz and 60 % delta-strain; characterized by an energy density of 1.25 J per kg of active material.

Dimopoulos, Emmanouil; Munk-Nielsen, Stig

2014-01-01

263

An efficiency improved single-phase PFC converter for electric vehicle charger applications  

DEFF Research Database (Denmark)

This paper presents an efficiency improved single-phase power factor correction (PFC) converter with its target application to plug-in hybrid electric vehicle (PHEV) charging systems. The proposed PFC converter features sinusoidal input current, three-level output characteristic, and wide range of output DC voltage. Moreover, the involved DC/DC buck conversion stage may only need to convert partial input power rather than full scale of input power, and therefore the system overall efficiency can be much improved. Through proper control of the buck converter, it is also possible to mitigate the double-line frequency ripple power that is inherent in a single-phase AC/DC system. Both simulation and experimental results are presented to show the effectiveness of this converter.

Zhu, Dexuan; Tang, Yi

2013-01-01

264

Diseño estático de un convertidor DC/DC reductor-elevador bidireccional  

Directory of Open Access Journals (Sweden)

Full Text Available This paper shows a buck-boost converter static design with 3 switches and cascade connection. The main application of the converter is the battery management on uninterruptible power supplies, cotrolling energy flow and regulating the DC supply voltage for the different battery operation modes as source and sink.

Marcela González Valencia

2010-06-01

265

Nuevo sistema de control para el seguimiento del punto de máxima potencia en paneles solares basado en el control predictivo de corriente de convertidores cc-cc / New control system for maximum power point tracking in solar panels based on dc-dc converter predictive current control  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Para obtener la máxima energía de un panel solar es necesario operarlo en el punto de máxima potencia, donde el producto de la tensión fotovoltaica generada y la corriente extraída es un máximo. En operación normal este punto cambia continuamente, lo que requiere de un sistema de seguimiento del pun [...] to de máxima potencia para optimizar la operación del panel. Los paneles solares presentan una característica no lineal en la curva corriente-voltaje, lo que hace difícil la utilización de algoritmos convencionales de seguimiento de puntos de operación donde se busca un máximo o un mínimo. Se ha demostrado que el algoritmo “perturbar y observar” (P&O) es adecuado para el seguimiento del punto de máxima transferencia de potencia sobre este sistema. Este trabajo presenta una simulación en Matlab Simulink del comportamiento del panel solar bajo irradiancias y temperaturas típicas. El modelo se usa para probar que un sistema de seguimiento del punto de máxima potencia del panel basado en el algoritmo P&O operando sobre un control predictivo de corriente aplicado a un convertidor CC-CC es capaz de encontrar y seguir eficientemente el punto de máxima transferencia de potencia frente a variaciones en las condiciones de irradiancia y temperatura en el panel. Abstract in english To get maximum energy from a solar panel it is necessary to operate in the maximum power point where the product of generated photovoltage and extracted current is a maximum. In normal operation this point changes continuously, therefore a maximum power point tracking system is required. Solar panel [...] s present a nonlinear characteristic in the current-voltage graph, complicating the use of standard operating point tracking algorithms to find a maximum power point. If has been shown that the "perturb and observe" (P&O) algorithm is adequate to achieve this task. This work presents a Simulink Matlab simulation of the solar panel behavior under constant irradiation and typical temperatures. This simulation is used to prove that a maximum power point tracking control based on the P&O algorithm manipulating a predictive current control applied to a DC-DC converter is able to find and efficiently follow the maximum power point under panel irradiance and temperature variations.

Erick, Baethge; Alberto, Berzoy; Víctor, Guzmán; María Isabel, Giménez.

266

Stability Constrained Efficiency Optimization for Droop Controlled DC-DC Conversion System  

DEFF Research Database (Denmark)

Paralleled dc converter systems are widely used in distribution systems and uninterruptable power supplies. This paper implements a hierarchical control in a droop-controlled dc-dc conversion system with special focus on improving system efficiency which is dealt within the tertiary regulation. As the efficiency of each converter changes with output power, virtual resistances (VRs) are set as decision variables for adjusting power sharing proportion among converters. It is noteworthy that apart from restoring the voltage deviation, secondary control plays an important role to stabilize dc bus voltage when implementing tertiary regulation. Moreover, system dynamic is affected when shifting VRs. Therefore, the stability is considered in optimization by constraining the eigenvalues arising from dynamic state space model of the system. Genetic algorithm is used in searching for global efficiency optimum while keeping stable operation. Simulation results are shown to demonstrate the effectiveness of the method.

Meng, Lexuan; Dragicevic, Tomislav

2013-01-01

267

Exploration of Charge Recycling DC-DC Conversion Using a Switched Capacitor Regulator  

Directory of Open Access Journals (Sweden)

Full Text Available The increasing popularity of DVFS (dynamic voltage frequency scaling schemes for portable low power applications demands highly efficient on-chip DC-DC converters. The primary aim of this work is to enable increased efficiency of on-chip DC-DC conversion for near-threshold operation of multicore chips. The idea is to supply nominal (high off-chip voltage to the cores which are then “voltage-stacked” to generate the near-threshold (low voltages based on Kirchhoff’s voltage law through charge recycling. However, the effectiveness of this implicit down-conversion is affected by the current imbalance among the cores. The paper presents a design methodology and optimization strategy for highly efficient charge recycling on-chip regulation using a push-pull switched capacitor (SC circuit. A dual-boundary hysteretic feedback control circuit has been designed for stacked loads. A stacked-voltage domain with its self-regulation capability combined with a SC converter has shown average efficiency of 78%–93% for 2:1 down-conversion with ILoad (max of 200 mA and workload imbalance varying from 0–100%.

Mircea R. Stan

2013-07-01

268

A Closed Form Expression for Predicting Fast Scale Instability in Switching Buck Converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fast scale instability is an undesired phenomenon in switching converters. In past studies, its prediction has been mainly carried out by deriving discrete time models and then linearizing the system in the vicinity of a fixed point. However, the results obtained from such an approach cannot be applied for design purpose except for simple cases of current mode control. Alternatively, in this paper, this phenomenon is analyzed by using a unified formal symbolic approach which can be applied fo...

El Aroudi Abdelali

2012-01-01

269

A Closed Form Expression for Predicting Fast Scale Instability in Switching Buck Converters  

Directory of Open Access Journals (Sweden)

Full Text Available Fast scale instability is an undesired phenomenon in switching converters. In past studies, its prediction has been mainly carried out by deriving discrete time models and then linearizing the system in the vicinity of a fixed point. However, the results obtained from such an approach cannot be applied for design purpose except for simple cases of current mode control. Alternatively, in this paper, this phenomenon is analyzed by using a unified formal symbolic approach which can be applied for different control strategies. This approach is based on expressing the condition for fast scale instability occurrence using Fourier series and then converting the result into a matrix form expression which depends explicitly on the system parameters making the results directly applicable for design purpose. Under certain practical conditions concerning these parameters, the matrix form expression can be approximated by standard polynomial functions depending on the operating duty cycle. The approximating polynomial functions are widely related to the well known Clausen polynomial functions. The results presented in this work clearly generalize the well known stability condition of current mode control.

El Aroudi Abdelali

2012-07-01

270

Análisis y comparación entre un controlador PI difuso y un controlador PI óptimo convencional para un conversor reductor Analysing and comparing a PI fuzzy controller and an optimal conventional PI controller for a buck converter  

Directory of Open Access Journals (Sweden)

Full Text Available nente. Tal tipo de dispositivos de electrónica de potencia convierten una tensión continua a otra de menor magnitud y cuyas ca- racterísticas de no linealidad son evidenciadas. Se presentan entonces, dos técnicas de control no lineal, la primera propuesta es un control óptimo PI (error proporcional e integral del error convencional, basado en la minimización del criterio ITSE (integral del cuadrado del error ponderado en el tiempo. Para ello se obtiene un modelo de la planta en un punto de operación. La se- gunda propuesta es un control difuso cuyos conjuntos de entrada y salida son también definidos minimizando el criterio ITSE en el sistema general, y estableciendo como entradas el error proporcional y la integral del error. A continuación se realiza una va- riación de la carga para establecer la eficiencia del sistema con los dos controladores mencionados. Se debe tener en cuenta que este tipo de sistemas no debe presentar sobretensiones considerables, ya que puede ocasionar daño en él. En este sentido, los parámetros encontrados en el diseño de los dos controladores corresponden a una metodología analítica y descriptiva. Los resultados obtenidos en simulación, y estableciendo como figura de mérito el índice de desempeño mencionado (ITSE y el con- sumo de potencia, muestra que la respuesta del sistema para el control difuso presenta un mayor consumo de potencia que el control óptimo, mientras que el ITSE obtenido es mayor para el control óptimo que para el difuso. Se concluye que la explora- ción de este tipo de conversores, utilizando técnicas de control no lineal y minimizando los diferentes índices de desempeño, es aplicable.This document proposes analysing and designing two control strategies for permanent current DC-DC buck converter. These kinds of electronic devices convert a constant-voltage to a lower constant-voltage (nonlinearity characteristics being demonstra- ted. Two nonlinear control techniques are shown. The first is a conventional optimal proportional error and integral error (PI controller based on minimising integral of time per squared errors (ITSE criteria. A model of the plant at an operation point was thus obtained. The second one was fuzzy control where input and output sets were also defined by minimising ITSE criteria in the overall system and establishing inputs such as proportional error and integral error. Load was then varied to establish the system’s efficiency with both the aforementioned controllers. It must be borne in mind that such systems should not present super-voltage since this can cause damage. The parameters found in designing both controllers thus corresponded to analytical and descriptive methodology. Simulation results, the performance index mentioned above (ITSE and power consumption showed that the sys- tem’s response for the fuzzy control drew more power consumption than the optimal controller; otherwise, obtained ITSE was lar- ger for the optimal control than the fuzzy control. It is concluded that exploring these types of converter is applicable when using nonlinear control techniques and minimising the different performance indices.

Soriano Jairo

2009-12-01

271

Análisis y comparación entre un controlador PI difuso y un controlador PI óptimo convencional para un conversor reductor / Analysing and comparing a PI fuzzy controller and an optimal conventional PI controller for a buck converter  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Este trabajo propone el análisis y diseño de dos estrategias de control para un conversor CC-CC reductor de corriente permanente. Tal tipo de dispositivos de electrónica de potencia convierten una tensión continua a otra de menor magnitud y cuyas características de no linealidad son evidenciadas. Se [...] presentan entonces, dos técnicas de control no lineal, la primera propuesta es un control óptimo PI (error proporcional e integral del error) convencional, basado en la minimización del criterio ITSE (integral del cuadrado del error ponderado en el tiempo). Para ello se obtiene un modelo de la planta en un punto de operación. La segunda propuesta es un control difuso cuyos conjuntos de entrada y salida son también definidos minimizando el criterio ITSE en el sistema general, y estableciendo como entradas el error proporcional y la integral del error. A continuación se realiza una variación de la carga para establecer la eficiencia del sistema con los dos controladores mencionados. Se debe tener en cuenta que este tipo de sistemas no debe presentar sobretensiones considerables, ya que puede ocasionar daño en él. En este sentido, los parámetros encontrados en el diseño de los dos controladores corresponden a una metodología analítica y descriptiva. Los resultados obtenidos en simulación, y estableciendo como figura de mérito el índice de desempeño mencionado (ITSE) y el consumo de potencia, muestra que la respuesta del sistema para el control difuso presenta un mayor consumo de potencia que el control óptimo, mientras que el ITSE obtenido es mayor para el control óptimo que para el difuso. Se concluye que la exploración de este tipo de conversores, utilizando técnicas de control no lineal y minimizando los diferentes índices de desempeño, es aplicable. Abstract in english This document proposes analysing and designing two control strategies for permanent current DC-DC buck converter. These kinds of electronic devices convert a constant-voltage to a lower constant-voltage (nonlinearity characteristics being demonstrated). Two nonlinear control techniques are shown. Th [...] e first is a conventional optimal proportional error and integral error (PI) controller based on minimising integral of time per squared errors (ITSE) criteria. A model of the plant at an operation point was thus obtained. The second one was fuzzy control where input and output sets were also defined by minimising ITSE criteria in the overall system and establishing inputs such as proportional error and integral error. Load was then varied to establish the system's efficiency with both the aforementioned controllers. It must be borne in mind that such systems should not present supervoltage since this can cause damage. The parameters found in designing both controllers thus corresponded to analytical and descriptive methodology. Simulation results, the performance index mentioned above (ITSE) and power consumption showed that the system's response for the fuzzy control drew more power consumption than the optimal controller; otherwise, obtained ITSE was larger for the optimal control than the fuzzy control. It is concluded that exploring these types of converter is applicable when using nonlinear control techniques and minimising the different performance indices.

Morales Laguado, Lina; Chamorro, Harold; Soriano, Jairo.

272

Digitally Controlled Point of Load Converter with Very Fast Transient Response  

DEFF Research Database (Denmark)

This paper presents a new Digital Self-Oscillating Modulator (DiSOM) that allows the duty cycle to be changed instantly. The DiSOM modulator is shown to have variable switching that is a function of the duty cycle. Compared to a more traditional digital PWM modulator based on a counter and comparator the DiSOM modulator allows the sampling frequency of the output voltage control loop to be higher than the switching frequency of the power converter, typically a DC/DC converter. The features of the DiSOM modulator makes it possible to design a digitally controlled DC/DC converter with linear voltage mode control and very fast transient response. The DiSOM modulator is combined with a digital PID compensator algorithm is implemented in a hybrid CPLD/FPGA and is used to control a synchronous Buck converter, which is used in typical Point of Load applications. The computational time is only three clock cycles from the time the A/D converter result is read by the control algorithm to the time the duty cycle command is updated. A typical POL converter has been built and the experimental results show that the transient response of the converter is very fast. The output voltage overshoot is only 2.5% of the nominal output voltage when a load step of 50% - 100% of nominal output current is applied to the converter. The settling time is approximately 8 PWM cycles.

Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.

2007-01-01

273

Parallel connection of high-power DC/DC power supply based on IGBT device  

International Nuclear Information System (INIS)

Parallel connection technique of DC/DC power supplies is adopted, and DC high-power supply is designed based on IGBT device, which can be used as the plasma displacement fast control power supply for EAST device. Based on the simulation and experiment, satisfactory dynamic and static performance of the DC/DC power supply was obtained. (authors)

2006-05-01

274

Bifurcation-free design method of pulse energy converter controllers  

International Nuclear Information System (INIS)

In this paper, a design method of pulse energy converter (PEC) controllers is proposed. This method develops a classical frequency domain design, based on the small signal modeling, by means of an addition of a nonlinear dynamics analysis stage. The main idea of the proposed method consists in fact that the PEC controller, designed with an application of the small signal modeling, is tuned after with taking into the consideration an essentially nonlinear nature of the PEC that makes it possible to avoid bifurcation phenomena in the PEC dynamics at the design stage (bifurcation-free design). Also application of the proposed method allows an improvement of the designed controller performance. The application of this bifurcation-free design method is demonstrated on an example of the controller design of direct current-direct current (DC-DC) buck converter with an input electromagnetic interference filter.

2009-12-15

275

Buck-type high power factor converter for a continuous current mode operation with suppressed ripple ripple component in the DC output voltage; Ripuru den'atsu wo yokuseishita atarashii renzoku modo hoshiki koatsukei koryokuritsu konbata  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a new circuit configuration for a buck-type active power filtering converter that achieves not only a distortion-free input current waveform in phase with the power supply voltage but also smaller and lighter reactors, with suppressed ripple component in the DC output voltage. This circuit operates in a continuous current mode, and is suitable for telecommunications power supplies with comparatively large capacities in the several KVA class. The deft use of an inexpensive control IC for a boost-type active power filtering converter in the buck-type converter is economical in that few components are needed for the current feedback control that is necessary for continuous current mode control. The characteristics of our proposed circuit configuration, operating principle, control strategy, and experimental results are described. (author)

Hirachi, K.; Matsukawa, K.; Tomokuni, Y.

1998-10-30

276

Optimal Design and Tradeoffs Analysis for Planar Transformer in High Power DC-DC Converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A planar magnetic is a low profile transformer or inductor utilizing planar windings instead of the traditional windings made of Cu-wires. In this paper, the important factors for planar transformer design including winding loss, core loss, leakage inductance and stray capacitance have been investigated individually. The tradeoffs among these factors have to be analyzed in order to achieve optimal parameters. Combined with a certain application, four typical winding arran...

Ouyang, Ziwei; Thomsen, Ole Cornelius; Andersen, Michael A. E.

2010-01-01

277

FC/Battery Power Management for Electric Vehicle Based Interleaved DC-DC Boost Converter Topology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Due to the fact that the environmental issues have become more serious recently, interest in renewable energy systems, such as, fuel-cells (FCs) has increased steadfastly. Among many types of FCs, proton exchange membrane FC (PEMFC) is one of the most promising power sources due to its advantages, such as, low operation temperature, high power density and low emission. However, using only PEMFC for electric vehicle may not be feasible to satisfy the peak demand changes especially during accel...

Benrabah, Ali; Khoucha, Farid; Herizi, Omar; Benbouzid, Mohamed; Kheloui, Abdelaziz

2013-01-01

278

Dynamic back propagation based MRAC with fuzzy emulator for DC-DC converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Model Reference Adaptive Control (MRAC) is commonly used in traditional neural network based adaptive controller design. Neural network based MRAC often requires plant emulator when neural controller is connected in between the plant and the control input. Several methodologies for constructing the plant emulator have been proposed but they require either off-line training of the plant emulator or an exact mathematical model of the plant. This limits the capability of a neural system to gener...

Kadwane, S. G.; Kumar, A.; Kuran, B. M.

2007-01-01

279

Design, Manufacturing and characterization of integrated inductors with magnetic layers for DC-DC converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents the conception, fabrication and characterization of integrated inductors containing magnetic layers. We require different steps of micro-technologies: preparation of glass and ferrite substrates, RF sputtering, photolithography, etching and finally electroplating techniques for copper and gold films. The geometrical magnitudes are determined by using HFSS simulator software. The measurements performed at low and high frequencies (up to 1 G...

Ali Siblini

2012-01-01

280

Modular DC/DC Converter for DC Distribution and Collection Networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A major change in the electrical transmission and distribution system is taking place in Europe at the moment. The shift from a centralised energy production to a distributed generation profoundly changes the behaviour of the grid. Environmental or social issues associated with the construction of new power lines to relieve bottlenecks, together with aged equipment dating from the 1960s, pose some serious challenges to government, the research communi...

2012-01-01

 
 
 
 
281

Usign Planar Transformers in Soft Switching DC/DC Power Converters  

Directory of Open Access Journals (Sweden)

Full Text Available In recent years, the demand for wide applications of highly regulated, reliable power supplies, and the desire to have smaller size, lighter weight and higher efficiency of power electronics systems has been increased. The tallest and heaviest components on printed-circuit-boards are often magnetic components. The answer for miniaturization and material performance can be planar magnetic technology. This paper focuses on the power planar magnetic circuits, with respect to application possibilities of these alternative and attractive magnetic components in modern, soft switching, low profile power supplies.

Gabriel Kacor

2004-01-01

282

Basic circuits to design switched-based DC-DC converters  

Directory of Open Access Journals (Sweden)

Full Text Available El propósito de este artículo es doble. Por un lado, se presentan conceptos básicos de circuitos conmutados para diseñar un convertidor CD–CD y, por el otro, se rescatan definiciones de electrónica de potencia asociadas a redes eléctricas simples. En el análisis de esas redes es necesario tomar en cuenta no solo las no idealidades de los convertidores sino también cómo minimizar pérdidas de potencia. Porque las perdidas de potencia pueden ser minimizadas aumentando la frecuencia de reloj de los convertidores conmutados, se presentan resultados experimentales de generadores de reloj. Estos circuitos fueron implementados con componentes de bajo costo.

F. Sandoval-Ibarra

2007-01-01

283

Design, Manufacturing and characterization of integrated inductors with magnetic layers for DC-DC converter  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the conception, fabrication and characterization of integrated inductors containing magnetic layers. We require different steps of micro-technologies: preparation of glass and ferrite substrates, RF sputtering, photolithography, etching and finally electroplating techniques for copper and gold films. The geometrical magnitudes are determined by using HFSS simulator software. The measurements performed at low and high frequencies (up to 1 GHz permit to verify the correlation between experiment and simulation results. The inductance of the manufactured spiral inductor is ??about 200 nH and it is constant from low frequency up to 0.9 GHz.

Ali Siblini

2012-08-01

284

Implementation of DC-DC converter with maximum power point tracking control for thermoelectric generator applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A heavy duty vehicle looses approximately 30-40 % of the energy in the fuel as waste heat through the exhaust system. Recovering this waste heat would make the vehicle meet the legislative and market demands of emissions and fuel consumption easier. This recovery is possible by transforming the waste heat to electric power using a thermoelectric generator. However, the thermoelectric generator electric characteristics makes direct usage of it unprotable, thus an electric power conditioner is ...

2012-01-01

285

Grid converter for LED based intelligent light sources  

DEFF Research Database (Denmark)

The purpose of this thesis was to investigate the applicability and effects of digital control to line connected switched mode power supplies with power factor correction. The main approach was cost effectiveness with high efficiency. This involved hardware design for increased switching frequency to reduce the size of the magnetic components. A description of different grid regulations was given followed by a set of converter topologies and controllers. Different control techniques were pointed out. Among the listed topologies and control solutions few were selected for further analysis, design and implementation. Many of different hardware and control solutions available on the market were investigated. Most of the commercial power supplies are controlled by dedicated analog controllers in form an integrated circuit. Thus a survey was conducted to analyze the available state-of-art analog controllers and their implemented control algorithms. As digital control has to be competitive with the existing solutions it was investigated what digital signal processing solutions exist. A performance and cost comparison was also presented. The chosen converter topologies were thoroughly analyzed. Different converters were chosen for different power levels. At low power simple boost converter as power factor corrector (PFC) and a RCD-clamped forward converter was chosen as DC-DC converter. This with has double output and coupled lter inductor. To design a digital controller with the tools of the classical control theory a small signal linearized model of the converter is needed. Detailed modeling and linearizing of the boost converter is presented. At high power level interleaving technique is frequently used to reduce the current stress on the switching components. Though the number of magnetic components is increased they became smaller in size resulting in smaller current ripple through them. An interleaved boost converter with two legs is selected as PFC converter. It was shown that the small signal model of theinterleaved converter is similar to the simple boost converter. Only the simple inductor has to be replaced by the paralleled inductors of each leg. This statement is valid only if the total inductor current is controlled rather than controlling the current in each leg. As second stage a phase-shifted full-bridge converter with synchronous rectication and current doubler was selected. It was shown that for output current and voltage control this topology can be modeled as a interleaved synchronous buck converter. As it can be seen interleaving technique is also present in this topology. For this topology a fuzzy logic voltage controller is proposed and compared to the traditional PI controller. After modeling the converters controllers can be designed. The controller design was interconnected with the hardware design and control platform. Thus two dfferent prototypes were designed and built with two dierent digital controllers and the controller design, analysis and implementation was based on these two case studies. The first prototype was a 70 W two-stage PFC and DC-DC converter with boost and forward converters. Average current mode control was selected, designed, simulated an implemented for the boost PFC converter. The two-loop control structure (fast internal current loop and lower bandwidth external voltage loop) was designed for nominal power but system behavior was also analyzed for low-load conditions. The controller was simulated in Matlab/Simulink using PLECS library and embedded Matlab function. All the parameters were treated and scaled just as they appear in the ADC interrupt of the 16 bit fixed point dsPIC30F1010 microcontroller. Peak current control was implemented for the forward converter, using analog comparator module of the digital-signal controller. The waveforms, eciency and power factor results were compared to the performance of an identical two stage 70 W power supply controlled with an analog PFC/PWM integrated circuit. The second prototype was a 600 W two-stage PFC and DC-DC converter with i

Török, Lajos

2011-01-01

286

Resonant power converters  

CERN Document Server

This book is devoted to resonant energy conversion in power electronics. It is a practical, systematic guide to the analysis and design of various dc-dc resonant inverters, high-frequency rectifiers, and dc-dc resonant converters that are building blocks of many of today's high-frequency energy processors. Designed to function as both a superior senior-to-graduate level textbook for electrical engineering courses and a valuable professional reference for practicing engineers, it provides students and engineers with a solid grasp of existing high-frequency technology, while acquainting them wit

Kazimierczuk, Marian K

2012-01-01

287

Recovery Act: Integrated DC-DC Conversion for Energy-Efficient Multicore Processors  

Energy Technology Data Exchange (ETDEWEB)

In this project, we have developed the use of thin-film magnetic materials to improve in energy efficiency of digital computing applications by enabling integrated dc-dc power conversion and management with on-chip power inductors. Integrated voltage regulators also enables fine-grained power management, by providing dynamic scaling of the supply voltage in concert with the clock frequency of synchronous logic to throttle power consumption at periods of low computational demand. The voltage converter generates lower output voltages during periods of low computational performance requirements and higher output voltages during periods of high computational performance requirements. Implementation of integrated power conversion requires high-capacity energy storage devices, which are generally not available in traditional semiconductor processes. We achieve this with integration of thin-film magnetic materials into a conventional complementary metal-oxide-semiconductor (CMOS) process for high-quality on-chip power inductors. This project includes a body of work conducted to develop integrated switch-mode voltage regulators with thin-film magnetic power inductors. Soft-magnetic materials and inductor topologies are selected and optimized, with intent to maximize efficiency and current density of the integrated regulators. A custom integrated circuit (IC) is designed and fabricated in 45-nm CMOS silicon-on-insulator (SOI) to provide the control system and power-train necessary to drive the power inductors, in addition to providing a digital load for the converter. A silicon interposer is designed and fabricated in collaboration with IBM Research to integrate custom power inductors by chip stacking with the 45-nm CMOS integrated circuit, enabling power conversion with current density greater than 10A/mm2. The concepts and designs developed from this work enable significant improvements in performance-per-watt of future microprocessors in servers, desktops, and mobile devices. These new approaches to scaled voltage regulation for computing devices also promise significant impact on electricity consumption in the United States and abroad by improving the efficiency of all computational platforms. In 2006, servers and datacenters in the United States consumed an estimated 61 billion kWh or about 1.5% of the nation's total energy consumption. Federal Government servers and data centers alone accounted for about 10 billion kWh, for a total annual energy cost of about $450 million. Based upon market growth and efficiency trends, estimates place current server and datacenter power consumption at nearly 85 billion kWh in the US and at almost 280 billion kWh worldwide. Similar estimates place national desktop, mobile and portable computing at 80 billion kWh combined. While national electricity utilization for computation amounts to only 4% of current usage, it is growing at a rate of about 10% a year with volume servers representing one of the largest growth segments due to the increasing utilization of cloud-based services. The percentage of power that is consumed by the processor in a server varies but can be as much as 30% of the total power utilization, with an additional 50% associated with heat removal. The approaches considered here should allow energy efficiency gains as high as 30% in processors for all computing platforms, from high-end servers to smart phones, resulting in a direct annual energy savings of almost 15 billion kWh nationally, and 50 billion kWh globally. The work developed here is being commercialized by the start-up venture, Ferric Semiconductor, which has already secured two Phase I SBIR grants to bring these technologies to the marketplace.

Shepard, Kenneth L

2013-03-31

288

Analog Circuit Design Low Voltage Low Power; Short Range Wireless Front-Ends; Power Management and DC-DC  

CERN Document Server

The book contains the contribution of 18 tutorials of the 20th workshop on Advances in Analog Circuit Design.  Each part discusses a specific to-date topic on new and valuable design ideas in the area of analog circuit design. Each part is presented by six experts in that field and state of the art information is shared and overviewed. This book is number 20 in this successful series of Analog Circuit Design, providing valuable information and excellent overviews of Low-Voltage Low-Power Data Converters - Chaired by Prof. Anderea Baschirotto, University of Milan-Bicocca Short Range Wireless Front-Ends - Chaired by Prof. Arthur van Roermund, Eindhoven University of Technology Power management and DC-DC - Chaired by Prof. M. Steyaert, Katholieke University Leuven Analog Circuit Design is an essential reference source for analog circuit designers and researchers wishing to keep abreast with the latest development in the field. The tutorial coverage also makes it suitable for use in an advanced design.

Roermund, Arthur; Baschirotto, Andrea

2012-01-01

289

Performance of Power Converters at Cryogenic Temperatures  

Science.gov (United States)

Power converters capable of operation at cryogenic temperatures are anticipated to play an important role in the power system architecture of future NASA deep space missions. Design of such converters to survive cryogenic temperatures will improve the power system performance and reduce development and launch costs. Aerospace power systems are mainly a DC distribution network. Therefore, DC/DC and DC/AC converters provide the outputs needed to different loads at various power levels. Recently, research efforts have been performed at the NASA Glenn Research Center (GRC) to design and evaluate DC/DC converters that are capable of operating at cryogenic temperatures. This paper presents a summary of the research performed to evaluate the low temperature performance of five DC/DC converters. Various parameters were investigated as a function of temperature in the range of 20 to -196 C. Data pertaining to the output voltage regulation and efficiency of the converters is presented and discussed.

Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.

2001-01-01

290

Design of Feedback Controller for Boost Converter Using Optimization Technique  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper a new method of controller design for boost type dc-dc converter is proposed. A feedback controller for DC-DC boost converter is designed to obtain constant output voltage of 24v.The optimal values of feedback controller is obtained using Genetic Algorithm (GA). Design equations are derived and it is modeled in MATLAB. Extensive simulation is carried out with linear controller parameters and the results are presented. To compare the output ...

Sesha Giri Rao Galam; Raghu, S.; Rajasekaran, N.

2012-01-01

291

Arranque suave para un motor de CD a través de un convertidor reductor CD-CD / Smooth Starter for a DC Machine through a DC-to-DC Buck Converter  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish En este artículo se presenta el diseño e implementación de un controlador de velocidad para un motor de CD a través de un convertidor reductor, el cual sigue una trayectoria de referencia suave diseñada mediante un polinomio de interpolación Bézier. El sistema reduce los picos súbitos de voltaje y c [...] orriente en el circuito de armadura del motor durante el arranque. El cálculo del control de velocidad se obtiene de una salida F llamada salida plana (calculada a través de la matriz de controlabilidad de Kalman). Este control se basa en la retroalimentación de todos los estados reescritos en términos de la salida plana y de sus derivadas sucesivas para el seguimiento de la trayectoria. Con la ayuda de la técnica de ubicación de polos es posible sintonizar adecuadamente el controlador en lazo cerrado. La efectividad del sistema se verifica experimentalmente mediante una plataforma que está compuesta por el convertidor reductor-motor CD y un modulador PWM. Abstract in english This article presents the design and implementation of a speed controller for a DC motor through a buck converter, which tracks a smooth reference trajectory designed by a Bezier polynomial interpolation. The system reduces voltage and current sudden peaks in the armature circuit of the motor during [...] the start. The calculation of the speed control is obtained from an output F called flat output (calculated through the Kalman controllability matrix). This control is based on feedback from all states rewritten in terms of the flat output and its successive derivatives for tracking the trajectory. With the aid of the pole placement technique it is possible to properly tune the controller in closed loop. The effectiveness of the system is verified experimentally by means of a platform that consists of the DC motor-buck converter and a PWM modulator.

Linares-Flores, J; Antonio-García, A; Orantes-Molina, A.

292

Three-phase buck-boost rectifier operating in discontinuous current conduction mode; Furenzoku denryu mode de dosasuru sanso shokoatsu seiryuki  

Energy Technology Data Exchange (ETDEWEB)

To reduce the supply current distortions and low power factor operations with a conventional diode bridge rectifier connected to the utility system, a novel three-phase single-way rectifier is presented in the paper. The circuit configuration is based on the buck-boost DC-DC converter, in which AC flyback inductors play a role of the energy storage/transfer. If the simple pulse width modulation with uniform duty factor is introduced and if the rectifier operates in discontinuous current conduction mode, the supply currents can be sinusoidally waveshaped with a near unity power factor. Moreover, the step-up/step-down characteristics of the output voltage can easily be obtained by appropriately adjusting the duty factor of the switches. The experimental setup, employing insulated-gate bipolar transistors as the power switching devices, is implemented and the state-space method is introduced to predict the voltage and current waveforms and steady-state characteristics. The experimental and simulated results confirm the relevance of the presented circuit configuration as an useful rectifier with sinusoidal supply currents and step-up/down output voltage regulation. 9 refs., 8 figs., 1 tab.

Oishi, H. [Oita National College of Technology, Oita (Japan); Okada, H. [Oita University, Oita (Japan); Miyaji, M.; Ishizaka, K.; Ito, R. [Fukuoka University, Fukuoka (Japan)

1995-04-20

293

Power Converters Secure Electronics in Harsh Environments  

Science.gov (United States)

In order to harden power converters for the rigors of space, NASA awarded multiple SBIR contracts to Blacksburg, Virginia-based VPT Inc. The resulting hybrid DC-DC converters have proven valuable in aerospace applications, and as a result the company has generated millions in revenue from the product line and created four high-tech jobs to handle production.

2013-01-01

294

Capacitor voltage balance limits in a multilevel-converter-based energy storage system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper studies an energy storage system based on a three-level DC-DC converter and a gridconnected neutral-point-clamped inverter. The main advantages of this multilevel power conversion system are highlighted and the neutral-point voltage oscillations are analyzed. A modulation algorithm for the DC-DC converter which includes the neutral-point voltage balance control is used to improve the voltage balancing capabilities of the inverter. Some figures are presented to show the ...

Burusteta, Sendoa; Pou Fe?lix, Josep; Ceballos Recio, Salvador; Marino, Iker; Alzola, Jose? A?ngel

2011-01-01

295

Analysis and Design of Embedded Controlled Parallel Resonant Converter  

Directory of Open Access Journals (Sweden)

Full Text Available Microcontroller based constant frequency controlled full bridge LC parallel resonant converter is presented in this paper for electrolyser application. An electrolyser is a part of renewable energy system which generates hydrogen from water electrolysis. The DC power required by the electrolyser system is supplied by the DC-DC converter. Owing to operation under constant frequency, the filter designs are simplified and utilization of magnetic components is improved. This converter has advantages like high power density, low EMI and reduced switching stresses. DC-DC converter system is simulated using MATLAB, Simulink. Detailed simulation results are presented. The simulation results are compared with the experimental results.

P. CHANDRASEKHAR

2009-07-01

296

New Geometry Integrated Inductors in Two-channel Interleaved Bidirectional Converter  

DEFF Research Database (Denmark)

A new geometry of integrated inductors for twochannel interleaved bidirectional converter is presented in this paper. The new geometry module integrates two individual inductors by stacking three I-cores. The middle I-core provides a shared flux path with low reluctance which uncouples the two inductors. The air gaps are constructed by separating the I-cores using copper foil windings with well-defined thickness. In this work, inverse connection and direct connection for the two integrated inductors have been analyzed. For the inverse connection, a unique saturation behavior in the middle I-core has been shown. The integrated inductors with new geometry make it possible to build low-profile, low-cost, flexibility DC/DC converters, and it can be extensively designed for low-voltage and high-current required by modern digital applications. Experiment results obtained from a 48V-12V 30A two-phase interleaved buck converter, demonstrates the difference in the inverse connection and the direct connection. Both efficiencies are above 91% from half to full output current.

Ouyang, Ziwei; Thomsen, Ole Cornelius

2010-01-01

297

A Novel Over-Current Protection Technique Applied to Peak-Current Type DC-DC Converter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The change of the over-current protection point of the power switches, caused by slope compensation, is analyzed in detail. It is discovered that the peak current protecting value increases as the duty cycle decreases. As a result, the safety operation of the switches is damaged greatly. A novel solution to improve over-current protection with constant peak current limitation is proposed by inducing synchronous slope compensation into the current limit function instead of the original constan...

2010-01-01

298

Switch mode power supply  

International Nuclear Information System (INIS)

This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

1993-01-01

299

Switch mode power supply  

Energy Technology Data Exchange (ETDEWEB)

This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

Kim, Hui Jun

1993-06-15

300

Design of Feedback Controller for Boost Converter Using Optimization Technique  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper a new method of controller design for boost type dc-dc converter is proposed. A feedback controller for DC-DC boost converter is designed to obtain constant output voltage of 24v.The optimal values of feedback controller is obtained using Genetic Algorithm (GA. Design equations are derived and it is modeled in MATLAB. Extensive simulation is carried out with linear controller parameters and the results are presented. To compare the output of the GA based design and BFOA, the controller parameters are also determined using conventional method (Z-N. Simulation results are validated through hardware results.

Sesha Giri Rao Galam

2012-12-01

 
 
 
 
301

Embedded Control of LCL Resonant Converter Analysis, Design, Simulation and Experimental Results  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Objective of this paper is to give more insight into CCM Operation of the LCL Converter to obtain op-timum design using state-space analysis and to verify the results using PSPICE Simulation for wide variation in loading conditions. LCL Resonant Full Bridge Converter (RFB) is a new, high performance DC-DC con-verter. High frequency dc-dc resonant converters are widely used in many space and radar power supplies owing to their small size and lightweight. The limitations of two element reso...

Selvaperumal, S.; Christober Asir Rajan, C.

2009-01-01

302

Commutation Processes in Multiresonant ZVS Bridge Converter  

Directory of Open Access Journals (Sweden)

Full Text Available The analysis of the multiresonant ZVS DC/DC bridge converter is presented. The control system of the converter is basedon the method of frequency control at the constant time of transistor turn-off with a phase shift. The operation of the circuit is givenand the operating range of the converter is defined where ZVS switching operation is assured. Control characteristics are given andthe converter’s efficiency is defined. The circuit’s operation is analysed on the basis of results of the converter simulation tests using Simplorer programme.

Miroslaw Luft

2008-01-01

303

A new configuration for multilevel converters with diode clamped topology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Due to the increased use of renewable energy and power elctronic applications, more multilevel converters (MLC) are developed. A Neutral Point Clamped (NPC) inverter is one of the most used multilevel topologies for wind turbine (WT) and photovoltaic (PV) applications. One of the most crucial points in this type of converter is dc-voltage control. In this paper, a novel multi output dc-dc converter connected to a diode clamped topology is presented. This converter, for a given duty cycles, is...

Nami, A.; Zare, F.; Ledwich, G.; Ghosh, A.; Blaabjerg, Frede

2008-01-01

304

Torus bifurcations in multilevel converter systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper considers the processes of torus formation and reconstruction through smooth and nonsmooth bifurcations in a pulse-width modulated DC/DC converter with multilevel control. When operating in a regime of high corrector gain, converters of this type can generate structures of stable tori embedded one into the other and with their basins of attraction delineated by intervening repelling tori. The paper illustrates the coexistence of three stable tori with different resonance behaviors ...

Zhusubaliyev, Zhanybai T.; Mosekilde, Erik; Yanochkina, Olga O.

2011-01-01

305

Bidirectional converter interface for a battery energy storage test bench  

DEFF Research Database (Denmark)

This paper presents the bidirectional converter interface for a 6 kV battery energy storage test bench. The power electronic interface consists a two stage converter topology having a low voltage dc-ac grid connected converter and a new dual active bridge dc-dc converter with high transformation ratio. The dc-dc converter controls the battery charge/discharge current while the grid converter controls the common dc-link voltage and the grid current. The applied control structures and the hardware implementation of both converters are presented, together with their interaction. Experimental results of the test bench show good performance for the bidirectional power flow with a maximum operating power of 100 kW.

Trintis, Ionut; Thomas, Stephan

2011-01-01

306

Wilbur "Buck" Clayton Collection  

Science.gov (United States)

For over fifty years, Wilbur "Buck" Clayton brought his special brand of trumpet magic to audiences around the world. Born in Parsons, Kansas, Clayton was a prominent member of Count Basie's orchestra and he went on tour for the State Department as well. This digital collection from the Miller Nichols Library at the University of Missouri-Kansas City presents over 1500 photographs from this collection documenting Clayton's life and career. Visitors can browse the collection, and there are some great photos of Clayton as a small child and of course, some excellent photos of him collaborating with other jazz legends like Pee Wee Russell, Joe Turner, and Buddy Tate. Visitors with an interest in specific images can use the search feature to look for items using each photograph's details.

307

Comparison of PID and Fuzzy Controlled DC to DC Converter with Inductor Resistance.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The DC-DC boost converter reveals highly non-linear and non-minimum phase properties, is very difficult task to design a controller that is healthy against load variation. For this purpose a Fuzzy PID Controller is proposed to control DC-DC boost converter which has a practical inductor and a series resistance. A balancing ProportionalIntegral-Differential (PID) controller to the parallel-damped passivity-based controller PD-PBC is also proposed for removing the steady state error even though...

2013-01-01

308

Comparison of PID and Fuzzy Controlled DC to DC Converter with Inductor Resistance.  

Directory of Open Access Journals (Sweden)

Full Text Available The DC-DC boost converter reveals highly non-linear and non-minimum phase properties, is very difficult task to design a controller that is healthy against load variation. For this purpose a Fuzzy PID Controller is proposed to control DC-DC boost converter which has a practical inductor and a series resistance. A balancing ProportionalIntegral-Differential (PID controller to the parallel-damped passivity-based controller PD-PBC is also proposed for removing the steady state error even though the parasitic resistance. MATLAB simulations are performed under step changes and load perturbations to measure the improvement in performance of the proposed approach.

R.Anand

2013-08-01

309

A New Hard Switching Bidirectional Converter With High Power Density  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a new isolated dc-dc bidirectional converter is proposed. This converter consists of two transformers (flyback and forward and only one switch in primary side and one switch in secondary side of transformers. In this converter energy transfers to the output in both on and off switch states so power density of this converter is high This converter controlled by PWM signal. Also this converter operates over a wide input voltage range. Theoretical analysis is presented and computer simulation and experimental results verify the converter analysis.

Bahador Fani

2010-01-01

310

Conference James F.Buckli  

CERN Multimedia

L'association du personnel a le plaisir d'accueillir Mons. James F.Buckli, astronaute, né en 1947. Il a participé à la mission Space Lab D1 qui pour la première fois mettait 8 personnes sur orbite.L'ass.du pers. remercie aussi Gordon White(s) de la mission américaine d'avoir permis d'organiser cette conférence

Buckli,J

1988-01-01

311

Simulation of closed loop controlled boost converter for solar installation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

With the shortage of the energy and ever increasing of the oil price, research on the renewable and green energy sources, especially the solar arrays and the fuel cells, becomes more and more important. How to achieve high stepup and high efficiency DC/DC converters is the major consideration in the renewable power applications due to the low voltage of PV arrays and fuel cells. In this paper digital simulation of closed loop controlled boost converter for solar installation is presented. Cir...

Kalirasu Athimulam; Dash Sekar Subharensu

2010-01-01

312

A New Asymmetrical Current-fed Converter with Voltage Lifting  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a new zero voltage switching current-fed DC-DC converter with high voltage gain. In this converter all switches (main and auxiliary) turn on under zero voltage switching and turn off under almost zero voltage switching due to snubber capacitor. Furthermore, the voltage spike across the main switch due to leakage inductance of forward transformer is absorbed. The flyback transformer which is connected to the output in series causes to high voltage gain and less voltage s...

Delshad, M.

2011-01-01

313

Modularized multilevel and z-source power converter as renewable energy interface for vehicle and grid-connected applications  

Science.gov (United States)

Due the energy crisis and increased oil price, renewable energy sources such as photovoltaic panel, wind turbine, or thermoelectric generation module, are used more and more widely for vehicle and grid-connected applications. However, the output of these renewable energy sources varies according to different solar radiation, wind speed, or temperature difference, a power converter interface is required for the vehicle or grid-connected applications. Thermoelectric generation (TEG) module as a renewable energy source for automotive industry is becoming very popular recently. Because of the inherent characteristics of TEG modules, a low input voltage, high input current and high voltage gain dc-dc converters are needed for the automotive load. Traditional high voltage gain dc-dc converters are not suitable for automotive application in terms of size and high temperature operation. Switched-capacitor dc-dc converters have to be used for this application. However, high voltage spike and EMI problems exist in traditional switched-capacitor dc-dc converters. Huge capacitor banks have to be utilized to reduce the voltage ripple and achieve high efficiency. A series of zero current switching (ZCS) or zero voltage switching switched-capacitor dc-dc converters have been proposed to overcome the aforementioned problems of the traditional switched-capacitor dc-dc converters. By using the proposed soft-switching strategy, high voltage spike is reduced, high EMI noise is restricted, and the huge capacitor bank is eliminated. High efficiency, high power density and high temperature switched-capacitor dc-dc converters could be made for the TEG interface in vehicle applications. Several prototypes have been made to validate the proposed circuit and confirm the circuit operation. In order to apply PV panel for grid-connected application, a low cost dc-ac inverter interface is required. From the use of transformer and safety concern, two different solutions can be implemented, non-isolated or isolated PV inverter. For the non-isolated transformer-less solution, a semi-Z-source inverter for single phase photovoltaic systems has been proposed. The proposed semi-Z-source inverter utilizes only two switching devices with doubly grounded feature. The total cost have been reduced, the safety and EMI issues caused by the high frequency ground current are solved. For the transformer isolated solution, a boost half-bridge dc-ac micro-inverter has been proposed. The proposed boost half-bridge dc-dc converter utilizes only two switching devices with zero voltage switching features which is able to reduce the total system cost and power loss.

Cao, Dong

314

A novel buck-boost inverter for photovoltaic systems  

Energy Technology Data Exchange (ETDEWEB)

Buck-boost operation of inverters is required for inverter-based PV systems in distributed grid-connected applications when variable resources can create large variations in the input voltage to inverters above and below the output AC voltage. This paper presented a general structure of a grid-connected PV system along with step-down and step-up operation of inverters. It also presented a newly developed, innovative single-phase, single-stage, flyback-based, buck-boost inverter for renewable energy conversion systems, especially for photovoltaic (PV) systems in both grid-connected and standalone applications. It focused on the analysis of the working principles, computer simulation of the operation, and design consideration of the inverter for grid-connected applications. The proposed buck-boost inverter has 4 switching devices. Three operation modes describe the operating principles of this buck-boost inverter. They are the charge mode, the positive half cycle (PHC) discharge mode, and the negative half cycle (NHC) discharge mode. It was concluded that the simple circuit topology of this inverter provides the possibility for a low cost and high efficiency dc-ac converter. The inverters have a low component count with only 3 power semiconductor switches to accomplish dc-ac conversion with a high output power quality. The inverter can accommodate a wide range of input dc voltage for better energy output from variable PV resources. The inverter separates the input source from the output grid through a flyback operation. Both the cost and size of the newly proposed inverter are lower than traditional buck inverters with line-frequency transformers, two-stage buck-boost inverters, and previous single-stage buck-boost inverters. The newly proposed inverted is therefore a more reliable and economical design for PV systems. The analysis of the working principles, and computer simulation of the operation for this inverter have proved its feasibility for dc-ac conversion in PV applications. However, the implementation and tests of the inverter are yet to be done. 4 refs., 1 tab., 22 figs.

Chang, L.; Liu, Z.; Xue, Y.; Guo, Z. [New Brunswick Univ., Fredericton, NB (Canada). Dept. of Electrical and Computer Engineering

2006-07-01

315

The electrical, thermal and spatial integration of a converter in a power electronic module:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis is concerned with the design and implementation of a power electronic system (14/42V DC/DC converter) that is implemented in the automotive environment, specifically the engine compartment. The power electronic system must have a high power density while operating in a high temperature environment.

2005-01-01

316

Implementation of Fuzzy Logic controller in Photovoltaic Power generation using Boost Converter and Boost Inverter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Increasing in power demand and shortage of conventional energy sources, researchers are focused on renewable energy. The proposed solar power generation circuit consists of solar array, boost converter and boost inverter. Low voltage, of photovoltaic array, is boosted using dc-dc boost converter to charge the battery and boost inverter convert this battery voltage to high quality sinusoidal ac voltage. The output of solar power fed from boost inverter feed to autonomous load without any inter...

Abubakkar Siddik A; Shangeetha M

2012-01-01

317

An Improved MPPT Interleaved Boost Converter for Solar Electric Vehicle Application  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An interleaved boost dc/dc converter is developed featuring smaller input/output filters, faster dynamic response and lower device stress than conventional designs, for solar electric vehicle (SEV) applications. The converter is connected between the photovoltaic power generation and dc bus in a multisource energy storage system of a SEV. Typically, interleaved converters require a current control loop to reduce the input current ripples, the output voltage ripples, and the size of passive co...

Khoucha, Farid; Benrabah, Ali; Herizi, Omar; Kheloui, Abdelaziz; Benbouzid, Mohamed

2013-01-01

318

Design and evaluation of tapped inductors for high-voltage auxiliary power supplies for modular multilevel converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tapped-inductor buck converters can provide large step-down ratios at high efficiency and are well suited in auxiliary power supplies for modular multilevel converter cells supplying gate drive units etc. In this paper the design and testing of three low-leakage tapped inductors for use in a 3kV, 100W buck converter is described.

Mode?er, Tomas; Zdanowski, Mariusz; Nee, Hans-peter

2012-01-01

319

Model of Bi-directional Flyback Converter for Hybrid AC/DC Distribution System  

Directory of Open Access Journals (Sweden)

Full Text Available In this article, a simulation model and concept of two switch bi-directional isolated DC/DC converter is presented. Converter is based on flyback converter type. Also control method for voltage regulation with bi-directional power transfer is presented. Target application of the proposed converter was selected to be a hybrid AC/DC distribution system concept of which was briefly described. The requirement of galvanic isolation in the hybrid AC/DC concept comes from use of shared neutral wire; DC current runs with unbalanced part of AC current in neutral wire. Without galvanic isolation grounded neutral would cause short circuit if DC/DC converter is connected to three phase rectifier or inverter. Simulation was carried out with PSCAD electromagnetic transient simulator.

Riku Pasonen

2013-12-01

320

Analisys of Current-Bidirectional Buck-Boost Based Automotive Switch-Mode Audio Amplifier  

DEFF Research Database (Denmark)

The following study was carried out in order to assess quantitatively the performance of the buck-boost converter when used as switch-mode audio amplifier. It comprises of, to begin with, the delimitation of design criteria based on the state-ofthe- art solution, which is based in a differential mode buck-based amplifier with a boost converter as power supply. The averaged switch modelling of the differential mode current bidirectional topology is also used, in order to analyze the steady state and frequency domain behaviour of this converter and parameterize it to meet the design criteria. Next, several piecewise-linear simulation results are shown with detail enough to emphasize the features of the converter. A simple prototype is implemented to verify the main predicted features. Presently no previous publication could be found containing a thorough analysis of this topology in such configuration when applied for audio.

Bolten Maizonave, Gert; Andersen, Michael A. E.

2011-01-01

 
 
 
 
321

Buck-Boost Impedance Networks  

DEFF Research Database (Denmark)

Most inverters designed to date can only perform either voltage-buck or boost operation with buck-boost mode usually attained by introducing additional active semiconductor devices and passive components to the inverters. Although effective, adding active switches will complicate the inverter control, and push up the overall system costs. Therefore, alternative topological solutions are of interest, and should preferably be implemented using only passive LC elements and diodes, connected as unique impedance networks. A number of possible network configurations are now investigated in this paper, and are respectively named as Z-source, H-source, EZ-source and their respective "inverted" variants. The presented impedance networks can either be used with a traditional voltage-source or current-source inverter, and can either be powered by a voltage or current source. All impedance networks are shown to produce the same voltage gain under the same operating conditions, but structurally, they have their respectiveadvantages and disadvantages, which are thoroughly described throughout the paper. Experimental results captured using a laboratory prototype are also presented for confirming the practicalities and performances of the described impedance networks.

Goh, Ailian; Gao, Feng

2007-01-01

322

Ideas on DC-DC Converters for Delivery of Low Voltage and High Currents for the SLHC / ILC Detector Electronics in Magnetic field and Radiation environments  

CERN Multimedia

For more efficient power transport to the electronics embedded inside large colliding beam detectors, we explore the feasibility of supplying 48 Volts DC and using local DCDC conversion to 2 V (or lower, depending upon on the lithography of the embedded electronics) using switch mode regulators located very close to the front end electronics. These devices will be exposed to high radiation and high magnetic fields, 10 – 100 Mrads and 2 - 4 Tesla at the SLHC, and 20 Krads and 6 Tesla at the ILC.

Dhawan, Satish; Neal, H; Sumner, R; Weber, M; Weber, R

2007-01-01

323

CONTROLLER DESIGN FOR SEPIC CONVERTER USING MODEL ORDER REDUCTION  

Directory of Open Access Journals (Sweden)

Full Text Available A SEPIC (Single-Ended Primary Inductor Converter is a DC-DC converter, capable of operating both in stepup or step-down mode and widely used in battery-operated applications. There are two possible modes of operation in the SEPIC converter: Continuous Conduction Mode (CCM and Discontinuous Conduction Mode (DCM. This paper presents modeling of a SEPIC converter operating in CCM using the State-Space Averaging (SSA technique. SEPIC converter consists of two inductor and two capacitor hence it is fourth order dc-dc converter. Design of feedback compensator for fourth order system is quite complex. In this paper, model order reduction technique is used for controller design of SEPIC converter. First small signal dynamic model for SEPIC converter is obtained using SSA technique which provides fourth order transfer function. Then this fourth order transfer function is reduced to second order using Padé approximation. Then the compensator is designed for the reduced order model of the SEPIC converter. Result shows that the compensator designed for reduced order model gives the quite satisfactory response with the original system

BINOD KUMAR PADHI, ANIRUDHA NARAIN

2013-06-01

324

COMPARISON OF PUSH-PULLAND NON-ISOLATED HIGH STEP – DOWN DC TO DC CONVERTERS  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with comparison of Non-isolated buck converter and pushpull converter. Here 48VDC is converted into high frequency AC and it is stepped down to 12V level. The push-pull converter has advantages like reduced switching losses, stresses and EMI. The power output of push-pull converter seems to be of high value compared to the non-isolated buck converter. The simulation results of Non-isolated converter and Push-Pull converter are compared.

S.DEVIKALA

2013-05-01

325

High Gain Interleaved Boost Converter for Fuel Cell Applications  

Directory of Open Access Journals (Sweden)

Full Text Available Fuel cell is one of the promising technologies for distributed generation. For designing high efficiency fuel cell power systems, a suitable DC-DC converter is required. Among the various topologies, interleaved converters using switched capacitor are considered as a better solution for fuel cell systems due to high conversion efficiency. The objective of the paper is to design and implement a high gain interleaved converter using switched capacitors for fuel cell systems. In the proposed interleaved converter, the front end inductors are magnetically cross-coupled to improve the electrical performance and reduce the weight and size. Also, switched capacitors are used to improve the voltage gain of the converter. The proposed converter has been performed. Simulation study of interleaved converter using switched capacitors interfaced with fuel cells has been studied using Matlab/Simulink. A prototype has been developed to verify the simulation results.

R. Seyezhai

2013-12-01

326

Analog Fixed Maximum Power Point Control for a PWM Step-downConverter for Water Pumping Installations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes a Fixed Maximum Power Point analog control used in a step-down Pulse Width Modulated power converter. The DC/DC converter drives a DC motor used in small water pumping installations, without any electric storage device. The power supply is provided by PV panels working around their maximum power point, with a fixed operating voltage value. The control circuit implementation is not only simple and cheap, but also robust and reliable. System protections and adjustments are ...

Beltran, H.; Perez, E.; Chen, Zhe; Gimeno-sales, F. J.; Segui?-chilet, S.; Soler, J.; Daroqui, E.

2009-01-01

327

Very High Frequency Interleaved Self-Oscillating Resonant SEPIC Converter  

DEFF Research Database (Denmark)

This paper describes analysis and design procedure of an interleaved, self-oscillating resonant SEPIC converter, suitable for operation at very high frequencies (VHF) ranging from 30 MHz to 300 MHz. The presented circuit consists of two resonant SEPIC DC-DC converters, and a capacitive interconnection network between the switches which provides self-oscillating and interleaved operation. A design approach to ensure zero voltage switching (ZVS) condition of the MOSFET devices is provided. To verify the proposed method, an 11 W, 50 MHz prototype was built using low-cost VDMOS devices and experimental results are presented. Peak achieved efficiency was 87%.

Kovacevic, Milovan; Knott, Arnold

2013-01-01

328

A New Topology for Power Factor Correction using Resonant Converters  

Directory of Open Access Journals (Sweden)

Full Text Available A new parallel-connected power flow technique is proposed to improve the input power factor with simultaneously output voltage regulation taking consideration of current harmonic standards. Paralleling of converter modules is used in medium-power applications to achieve the desired output power by using smaller size of high frequency transformers. A parallel-connected interleaved structure offers smaller passive components with less loss in continuous conduction inductor current mode and also reduces the volt-ampere rating of resonant (DC/DC converter. MATLAB/SIMULINK is used for implementation and simulation results show the performance improvement.

V V Vijetha Inti

2013-09-01

329

Fuzzy Controlled Parallel AC-DC Converter for PFC  

Directory of Open Access Journals (Sweden)

Full Text Available Paralleling of converter modules is a well-known technique that is often used in medium-power applications to achieve the desired output power by using smaller size of high frequency transformers and inductors. In this paper, a parallel-connected single-phase PFC topology using flyback and forward converters is proposed to improve the output voltage regulation with simultaneous input power factor correction (PFC and control. The goal of the control is to stabilize the output voltage of the converter against the load variations. The paper presents the derivation of fuzzy control rules for the dc/dc converter circuit and control algorithm for regulating the dc/dc converter. This paper presents a design example and circuit analysis for 200 W power supply. The proposed approach offers cost effective, compact and efficient AC/DC converter by the use of parallel power processing. MATLAB/SIMULINK is used for implementation and simulation results show the performance improvement.

M Subba Rao

2011-01-01

330

A Single-Phase Bidirectional Inverter with Two Buck/Boost MPPTs for DC- Distribution Applications  

Directory of Open Access Journals (Sweden)

Full Text Available An integration and operation of a single-phase bidirectional inverter with two buck/boost maximum power point trackers (MPPTs for dc-distribution applications. In a dc-distribution system, a bidirectional inverter is required to control the power flow between dc bus and ac grid, and to regulate the dc bus to a certain range of voltages. A droop regulation mechanism according to the inverter inductor current levels to reduce capacitor size, balance power flow, and accommodate load variation is proposed. Since the photovoltaic (PV array voltage can vary from 0 to 5000 V, especially with thin-film PV panels, the MPPT topology is formed with buck and boost converters to operate at the dc-bus voltage around 4000 V, reducing the voltage stress of its followed inverter. Additionally, the controller can online check the input configuration of the two MPPTs, equally distribute the PV-array output current to the two MPPTs in parallel operation, and switch control laws to smooth out mode transition. A comparison between the conventional boost MPPT and the proposed buck/boost MPPT integrated with a PV inverter is also presented. A single-phase bidirectional inverter with two buck/boost maximum power point trackers (MPPTs by using the closed loop circuit. This project is workout by simulink using mat lab.

V.Karthick

2014-04-01

331

Implementación de un control deslizante y su efecto en la dinámica y la robustez del convertidor buck  

Directory of Open Access Journals (Sweden)

Full Text Available Normal 0 21 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Normal 0 21 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} En este trabajo se presenta la implementación de un control por modo deslizante (CMD para un convertidor DC-DC Buck. Un breve análisis de la estructura de control es explicado. El modelo de simulación del convertidor con su circuito de control fue construido en Matlab®/Simulink. Se realiza una implementación práctica a partir de la construcción de un prototipo de convertidor Buck, controlado desde una PC con Matlab®/Simulink/Real-Time  Windows Target, utilizando la tarjeta NI-PCI-6221.Se acomete un estudio de la respuesta dinámica del convertidor, mostrandose la robustez en el desempeño de dicho sistema.

Alexander Fernández Correa

2011-09-01

332

An integrated flyback converter for DC uninterruptible power supply  

Energy Technology Data Exchange (ETDEWEB)

An integrated flyback converter performing the combined functions of uninterruptible power supply (UPS) and switch-mode power supply (SMPS) is presented. This converter has a high voltage main power input and a low voltage backup battery input. DC output is obtained form the main input via a flyback converter during normal operation and from the backup battery via another flyback converter when input power fails. High conversion efficiency is achieved in normal, backup, and charging modes as there is only a single dc-dc conversion in each mode. The converter circuit is very simple, with two switching transistors, a relay for mode switching, and a single magnetic structure only. This new design offers substantial improvement in efficiency, size, and cost over the conventional cascade of UPS and SMPS due to single voltage conversion, high frequency switching, and removal of design redundancy. The operation, design, analysis, and experimental results of the converter are presented.

Ma, K.W. [Ericsson Ltd., Quarry Bay (Hong Kong). Energy System Div.; Lee, Y.S. [Hong Kong Polytechnic Univ., Kowloon (Hong Kong). Dept. of Electronic Engineering

1996-03-01

333

HI-BRIDGE RESONANT SOFT-SWITCHED BOOST CONVERTER  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a high step-up DC-DC converter. The proposed converter comprises of a boost converter with an auxiliary switch and resonant circuit. The resonant circuit consists of a resonant inductor, two resonant capacitors, two diodes and an auxiliary switch. These resonant components make partial resonant path for the main and auxiliary switch to perform soft switching under the zero voltage condition using the resonant circuit. The proposed boost converter improves the whole system’s efficiency, by reducing the switching losses. The proposed soft switching boost converter has been simulated in PSIM software. The performance of the proposed boost converter is verified through the theoretical analysis and simulation results.

ELANGOVAN.S, MARIMUTHU. M, VIJYALASKMI

2013-04-01

334

Optimal Control of Hybrid Photovoltaic/Battery Energy Storage System for Mitigating Voltage Sag  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents development of an optimal control strategy for a hybrid photovoltaic/battery energy storage (PV/BES) system. The fluctuations at the DC bus voltage due to voltage sag were mitigated by using charge/discharge capability of the BES through the DC/DC buck/boost converter. Furthermore, an optimization of system control parameters responsible for DC bus voltage regulation within the grid side voltage-sourced converter and DC/DC buck/boost converter were introduced by using simp...

2012-01-01

335

A new configuration for multilevel converters with diode clamped topology  

DEFF Research Database (Denmark)

Due to the increased use of renewable energy and power elctronic applications, more multilevel converters (MLC) are developed. A Neutral Point Clamped (NPC) inverter is one of the most used multilevel topologies for wind turbine (WT) and photovoltaic (PV) applications. One of the most crucial points in this type of converter is dc-voltage control. In this paper, a novel multi output dc-dc converter connected to a diode clamped topology is presented. This converter, for a given duty cycles, is able to regulate the capacitor voltage to provide an appropriate input voltage for NPC regardless of load changes which can avoid neutral point balancing problem in such converters. In addition, the presented topology is suitable for renewable energy systems to boost the low rectified output-voltage. In order to verify the proposed topology, steady state analysis, modelling and simulations are carried out.

Nami, A.; Zare, F.

2008-01-01

336

An Innovative Reconfigurable Integrated Converter Topology Suitable for Distributed Generation  

Directory of Open Access Journals (Sweden)

Full Text Available The electricity market and environmental concerns, with wide utilization of renewable sources, have improved the diffusion of distributed generation units changing the operations of distribution grids from passive networks to microgrids. A microgrid includes a cluster of electrical loads, energy storage devices and microsources, which provide both power and heat to their local area. A microgrid has usually one connection point to the utility grid through power electronic converters placed at customers’ sites. This paper analyses a Reconfigurable Integrated Converter (RIC used for a domestic microgrid with inputs from the AC mains and photovoltaic arrays, and two DC outputs at different voltage levels. A RIC as a dual-boost DC-DC converter is proposed, modelled and analysed in the paper. The advantages of such a topology in comparison with traditional boost converters are outlined. Reported simulations results give evidence on the controllability of this converter and the capability of achieving the desired voltage outputs with reduced ripple.

Renato Rizzo

2012-09-01

337

Soft-switching PWM full-bridge converters topologies, control, and design  

CERN Document Server

Soft-switching PWM full-bridge converters have been widely used in medium-to-high power dc-dc conversions for topological simplicity, easy control and high efficiency. Early works on soft-switching PWM full-bridge converter by many researchers included various topologies and modulation strategies.  However, these works were scattered, and the relationship among these topologies and modulation strategies had not been revealed. This book intends to describe systematically the soft-switching techniques for pulse-width modulation (PWM) full-bridge converters, including the topologies, control and

Ruan, Xinbo

2014-01-01

338

Torus bifurcations in multilevel converter systems  

DEFF Research Database (Denmark)

This paper considers the processes of torus formation and reconstruction through smooth and nonsmooth bifurcations in a pulse-width modulated DC/DC converter with multilevel control. When operating in a regime of high corrector gain, converters of this type can generate structures of stable tori embedded one into the other and with their basins of attraction delineated by intervening repelling tori. The paper illustrates the coexistence of three stable tori with different resonance behaviors and shows how reconstruction of these tori takes place across the borders of different dynamical regimes. The paper also demonstrates how pairs of attracting and repelling tori emerge through border-collision torus-birth and border-collision torus-fold bifurcations. © 2011 World Scientific Publishing Company.

Zhusubaliyev, Zhanybai T.; Mosekilde, Erik

2011-01-01

339

CMOS-Compatible SOI MESFETS for Radiation-Hardened DC-to-DC Converters  

Science.gov (United States)

A radiation-tolerant transistor switch has been developed that can operate between 196 and +150 C for DC-to-DC power conversion applications. A prototype buck regulator component was demonstrated to be performing well after a total ionizing dose of 300 krad(Si). The prototype buck converters showed good efficiencies at ultra-high switching speeds in the range of 1 to 10 MHz. Such high switching frequency will enable smaller, lighter buck converters to be developed as part of the next project. Switching regulators are widely used in commercial applications including portable consumer electronics.

Thornton, Trevor; Lepkowski, William; Wilk, Seth

2013-01-01

340

Active converter based on the VIENNA rectifier topology interfacing a three-phase generator to a DC-bus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

AC-DC converters find application in every day life as a front-end to DC-DC and DC-AC converters. Active three-phase converters shape the three-phase input current to be sinusoidal and to be in-phase with the input voltage, as well as to provide a steady DC output voltage. This thesis investigates various active three-phase rectifier and control topologies and identifies a rectifier and control topology most suitable for use in converting a variable voltage variable frequency generator out...

2007-01-01

 
 
 
 
341

Active converter based on the VIENNA rectifier topology interfacing a three-phase generator to a DC-bus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

AC-DC converters find application in every day life as a front-end to DC-DC and DC-AC converters. Active three-phase converters shape the three-phase input current to be sinusoidal and to be in-phase with the input voltage, as well as to provide a steady DC output voltage. This thesis investigates various active three-phase rectifier and control topologies and identifies a rectifier and control topology most suitable for use in converting a variable voltage variable frequency generator output...

2007-01-01

342

Reduction of DC-link Capacitor in Case of Cascade Multilevel Converters by means of Reactive Power Control  

DEFF Research Database (Denmark)

A method to selectively control the amount of dc link voltage ripple by processing desired reactive power by a DC/DC converter in isolated AC/DC or AC/DC/AC system is proposed. The concept can reduce the dc link capacitors used for balancing the input and output power and thereby limiting the voltage ripple. It allows the use of smaller dc link capacitor and hence a longer lifetime and at the same time high power density and low cost can be achieved. The isolated DC/DC converter is controlled to process the desired reactive power in addition to the active power. The control system to achieve this selective degree of compensation is proposed. Simulation results are also presented to support the idea.

Gohil, Ghanshyamsinh Vijaysinh; Wang, Huai

2014-01-01

343

Light-weight DC to very high voltage DC converter  

Energy Technology Data Exchange (ETDEWEB)

A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current.

Druce, Robert L. (Union City, CA); Kirbie, Hugh C. (Dublin, CA); Newton, Mark A. (Livermore, CA)

1998-01-01

344

Analysis of current-bidirectional buck-boost based switch-mode audio amplifier  

DEFF Research Database (Denmark)

The following studdy was carried out in order to assses quantitatively the performannce of the buck--boost converter whhen used as swiitch-mode audio amplifier. It comprises of, to beggin with, the de limitation of design criteria bassed on the state of-the-art solution, which is based in a differential mode buckbased amplifier with a boost converter as power supply. The averaged switch modelling of the differential mode current bidirectional topology is also used, in order to analyze the steady state and frequency-wise behaviour of this converter and parameterize it to meet the design criteria. Next, several piecewise-linear siimulation resultss are shown with detail enough to emphasize the features of the converter. A simple prototype is implemented to verify the main predicted features. Presently no previous publicat ion could be found containing a thorough analysis of this topology in such configuration when applied for audio.

Bolten Maizonave, Gert; Andersen, Michael A. E.

2011-01-01

345

ANALYSIS OF PHOTOVOLTAIC CELLS WITH CLOSED LOOP BOOST CONVERTER  

Directory of Open Access Journals (Sweden)

Full Text Available The Conventional sources of energy are rapidly depleting and cost of power has been escalating day by day. Thus an alternative renewable source of energy has become a vital necessity. Photovoltaic system is one of the most promising renewable sources of energy. Its ability to produce power by directly converting solar energy has led to tremendous surge in its demand. The output power generated by it is very less but can be increased by interfacing it with boost converter. Therefore we have proposed a model of Photovoltaic array interfaced with closed loop dc-dc boost converter which considerably steps up the output voltage which could meet the demand of power. In this paper the various characteristics of PV cells and design parameters of boost converter have been discussed in detail. The results and graphs of simulink and hardware model have been compared and discussed.

Moumi Pandit

2013-03-01

346

A New Asymmetrical Current-fed Converter with Voltage Lifting  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a new zero voltage switching current-fed DC-DC converter with high voltage gain. In this converter all switches (main and auxiliary turn on under zero voltage switching and turn off under almost zero voltage switching due to snubber capacitor. Furthermore, the voltage spike across the main switch due to leakage inductance of forward transformer is absorbed. The flyback transformer which is connected to the output in series causes to high voltage gain and less voltage stress on the power devices. Considering high efficiency and voltage gain of this converter, it is suitable for green generated systems such as fuel cells or photovoltaic systems. The presented experimental results verify the integrity of the proposed converter.

DELSHAD, M.

2011-05-01

347

Embedded Control of LCL Resonant Converter Analysis, Design, Simulation and Experimental Results  

Directory of Open Access Journals (Sweden)

Full Text Available The Objective of this paper is to give more insight into CCM Operation of the LCL Converter to obtain op-timum design using state-space analysis and to verify the results using PSPICE Simulation for wide variation in loading conditions. LCL Resonant Full Bridge Converter (RFB is a new, high performance DC-DC con-verter. High frequency dc-dc resonant converters are widely used in many space and radar power supplies owing to their small size and lightweight. The limitations of two element resonant topologies can be over-come by adding a third reactive element termed as modified series resonant converter (SRC. A three ele-ment resonant converter capable of driving voltage type load with load independent operation is presented. We have used embedded based triggering circuit and the embedded ‘C’ Program is checked in Keil Software and also triggering circuit is simulated in PSPICE Software. To compare the simulated results with hardware results and designed resonant converter is 200W and the switching frequency is 50 KHz.

C. Christober Asir Rajan

2009-06-01

348

A comparison of resonant converters operating with a double-layer capacitor source  

Energy Technology Data Exchange (ETDEWEB)

Double-layer capacitors, with their high energy storage capability, may be utilized to supply peak power requirements in systems such as electric vehicles. As energy is drawn from a bank of double-layer capacitors, the voltage at the terminals of the capacitor bank decreases. Seventy-five percent of the initial energy stored in the capacitor bank can be utilized if the voltage is allowed to decrease to one-half of its initial value. The capacitor bank can be augmented with a dc-dc converter to present a constant voltage to an external system as the capacitor bank voltage decreases. Discussed in this paper is a comparison of three basic resonant dc-dc converter circuits when used as the converter with such a capacitor bank. Simple equivalent circuits are developed for each converter using a single frequency approximation of the various converter waveforms. Expressions for the voltage gain and the phase angle of the input current for each converter are derived from these equivalent circuits and plotted as a function of frequency. Issues related to the selection and design of a converter for this application are discussed.

Nelms, R.M. [Auburn Univ., AL (United States). Dept. of Electrical Engineering

1997-12-31

349

Geology Fieldnotes: Buck Island Reef National Monument, Virgin Islands  

Science.gov (United States)

This National Park Service (NPS) site covers the geology of Buck Island Reef National Monument in the Virgin Islands. It discusses coral reef formation and characteristics, as well as the history of Buck Island. There are links for maps, visitor information, and more details about this monument.

350

A Research on Sexual Performance in Rams and Bucks  

Directory of Open Access Journals (Sweden)

Full Text Available Sexual performance of bucks is enhanced by viewing the mating activities of the other males prior to being placed with sexually receptive sheep. This same experience has no effect on the sexual performance of rams. In this study, 15 rams and 15 bucks were individually permitted to sniff and nuzzle the genital region of an oestrus female and engage in before mating behaviours. In the sexual stimulation treatments, bucks were found more sexually active than rams (p<0.01. However, sexual stimulation did not affect the subsequent sexual performance of either species. Bucks and rams did not differ in the number of completed matings, but bucks exhibited more mounts without ejaculation (p<0.01 and more mounts per service (p<0.01 than rams.

T. Taskin

2004-01-01

351

Three phase six-switch PWM buck rectifier with power factor improvement  

International Nuclear Information System (INIS)

Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, three phase six-switch PWM buck rectifier is presented which operates at nearly unity power factor and provides variable output voltage. Small size energy storing components are required depending upon switching frequency. MATLAB simulation is performed and modified Sinusoidal Pulse Width Modulation (SPWM) switching technique is used in 3kW prototype converter to demonstrate low input current THD, nearly unity displacement factor, well regulated output voltage and reduced switching losses compared to conventional SPWM.

2013-06-10

352

Wave Energy Conversion : Simulation Verification and Linearization of Direct Drive Wave Energy Converter with Variable DC-link Voltage Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Lowering the cost of wave energy conversion is an essential task for it to succeed as a future energy resource. In this work a converter, assumed cheaper than the regular back to back converter setting, have been investigated for a electric direct drive point absorber. Both experimental work and simulations are used in the analysis. In the experimental work, a permanent magnet generator with a 6-pulse diode rectifier, a DC-link and a DC/DC converter equivalent, was used. Steady state, dynamic...

Ditlefsen, Arne Marius

2009-01-01

353

A VHF Interleaved Self-Oscillating Resonant SEPIC Converter with Phase-Shift Burst-Mode Control  

DEFF Research Database (Denmark)

This paper presents design and implementation of the phase-shift burst-mode control method for interleaved selfoscillating resonant SEPIC converters for LED lighting applications. The proposed control method utilizes delays in the turn-on and turn-off of the power stage and control circuitry in order to reduce requirements for the comparator in the regulation circuit. The control method is experimentally evaluated on a 49 MHz dc-dc converter prototype, and the results are presented. The designed converter demonstrates peak efficiency of 81%, maintains efficiency above 75% from 20% load to full load, and is implemented using low-cost switches and integrated circuits.

Kovacevic, Milovan; Knott, Arnold

2014-01-01

354

High-feedback Operation of Power Electronic Converters  

DEFF Research Database (Denmark)

The purpose of this review is to provide a survey of some of the most important bifurcation phenomena that one can observe in pulse-modulated converter systems when operating with high corrector gain factors. Like other systems with switching control, electronic converter systems belong to the class of piecewise-smooth dynamical systems. A characteristic feature of such systems is that the trajectory is â??sewedâ? together from subsequent discrete parts. Moreover, the transitions between different modes of operation in response to a parameter variation are often qualitatively different from the bifurcations we know for smooth systems. The review starts with an introduction to the concept of border-collision bifurcations and also demonstrates the approach by which the full dynamics of the piecewise-linear, time-continuous system can be reduced to the dynamics of a piecewise-smooth map. We describe the main bifurcation structures that one observes in three different types of converter systems: (1) a DC/DC converter; (2) a multi-level DC/DC converter; and (3) a DC/AC converter. Our focus will be on the bifurcations by which the regular switching dynamics becomes unstable and is replaced by ergodic or resonant periodic dynamics on the surface of a two-dimensional torus. This transition occurs when the feedback gain is increased beyond a certain threshold, for instance in order to improve the speed and accuracy of the output voltage regulation. For each of the three converter types, we discuss a number of additional bifurcation phenomena, including the formation and reconstruction of multi-layered tori and the appearance of phase-synchronized quasiperiodicity. Our numerical simulations are compared with experimentally observed waveforms.

Zhusubaliyev, Zhanybai T.; Mosekilde, Erik

2013-01-01

355

High-Feedback Operation of Power Electronic Converters  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this review is to provide a survey of some of the most important bifurcation phenomena that one can observe in pulse-modulated converter systems when operating with high corrector gain factors. Like other systems with switching control, electronic converter systems belong to the class of piecewise-smooth dynamical systems. A characteristic feature of such systems is that the trajectory is “sewed” together from subsequent discrete parts. Moreover, the transitions between different modes of operation in response to a parameter variation are often qualitatively different from the bifurcations we know for smooth systems. The review starts with an introduction to the concept of border-collision bifurcations and also demonstrates the approach by which the full dynamics of the piecewise-linear, time-continuous system can be reduced to the dynamics of a piecewise-smooth map. We describe the main bifurcation structures that one observes in three different types of converter systems: (1 a DC/DC converter; (2 a multi-level DC/DC converter; and (3 a DC/AC converter. Our focus will be on the bifurcations by which the regular switching dynamics becomes unstable and is replaced by ergodic or resonant periodic dynamics on the surface of a two-dimensional torus. This transition occurs when the feedback gain is increased beyond a certain threshold, for instance in Electronics 2013, 2 114 order to improve the speed and accuracy of the output voltage regulation. For each of the three converter types, we discuss a number of additional bifurcation phenomena, including the formation and reconstruction of multi-layered tori and the appearance of phase-synchronized quasiperiodicity. Our numerical simulations are compared with experimentally observed waveforms.

Gennady Y. Mikhal'chenko

2013-03-01

356

Novel Multiple DC-Inputs Direct Electric-Power Converter  

Science.gov (United States)

A new multiple dc-inputs direct electric-power converter (D-EPC) has been developed. It is placed between multiple dc power sources and an ac motor, thereby eliminating the need for a dc/dc converter that is generally used in conventional converter/inverter systems. D-PEC can improve the efficiency of a motor drive system with a more compact size. Its power distribution control is carried out by allotting voltage ratios to each of the two different dc power sources on a time average basis. A new pulse width modulation (PWM) generation technique to drive the switching devices in D-EPC has also been developed. Tests have verified that the three-phase ac motor can be operated by controlling the power distribution between the two power sources.

Yoshimoto, Kantaro; Takahashi, Kouji; Okushima, Keiji; Tani, Kazuhiko

357

Closed-loop digital control of resonant converters  

Science.gov (United States)

A sampled-data model to describe the dynamics of small perturbations of the cyclic steady state of resonant converters and the associated transfer functions were obtained previously. A discrete microprocessor-based controller, designed using the above dynamic model, has been built and tested on a simulated series resonant dc-dc converter. The control methods implemented are state feedback and periodic output feedback, each designed to achieve a specified set of closed-loop poles. Results for the closed-loop response show an improvement over those for the open-loop response. The effect of the delay caused by computer calculations on the closed-loop dynamics of the converter is investigated, showing that this delay can be important and should be modeled in the dynamics.

Elbuluk, Malik E.

358

A Z-source single phase matrix converter with safe commutation strategy  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a type of converter that can buck and boost with step-changed frequency called a Single-Phase Z-Source Buck-Boost Matrix Converter. It employs a safe-commutation strategy which results in the elimination of voltage spikes on switches without the need of a snubber circuit. This is facilitated through proper switching control algorithm. The operating principles of this converter are described and the circuit behaviour is confirmed by MATLAB / Simulink simulation results.

P. Deivasundari , V. Jamuna

2011-05-01

359

Component-Minimized Buck-Boost Voltage Source Inverters  

DEFF Research Database (Denmark)

This paper presents the design of buck-boost B4 inverters that can be derived from either Ä?uk- or SEPIC-derived buck-boost B6 inverters. Unlike traditional inverters, the integration of front-end voltage boost circuitry and inverter circuitry allows it to perform buck-boost voltage inversion. In order to form a distinct neutral potential in the corresponding voltage boost circuitry for correct B4 inverter operation, necessary modifications are derived step by step. The resulted dc networks with symmetrical placement of passive components allow complete charging and equal energy distribution between capacitors. Modulation wise, the proposed buck-boost B4 inverters can be controlled using a carefully designed carrier-based pulse-width modulation (PWM) scheme that will always ensure balanced threephase outputs as desired, while simultaneously achieving minimal voltage stress across semiconductors. Besides the advantage of reduced active components, buck-boost B4 inverters use a little more passive components when compared with buck-boost B6 inverters, which would allow a selectable tradeoff in practice. Moreover, analysis for discontinuous conduction mode of inductor current reveals the additional voltage relationship between dc input and ac output which is beyond the expectation when continuous inductor current is assumed. These theoretical findings, together with the inverter practicality, have been confirmed in Matlab/PLECS simulations and  experimentally using laboratory implemented inverter prototypes.

Gao, F.; Loh, P.C.

2007-01-01

360

Radiation Resistant DC- DC Power Conversion with Voltage Ratios > 10 Capable of Operating in High Magnetic Field for LHC Upgrade Detectors  

CERN Document Server

Commercial power converters that have voltage ratios greater than ten and are capable of running near the LHC collision region would increase the efficiency of the power distribution system of the ATLAS Silicon Tracker high luminosity upgrade. The devices must operate in a high magnetic field (2 T) and be radiation hard to ~50-100 Mrad and ~1015 Neq/cm2. These converters are to be mounted on the same multi-chip modules as the ASIC readout chips or in close vicinity without introducing any additional readout noise due to the high switching frequencies. Such devices will permit higher voltage power delivery to the tracker and thus increase overall power efficiency by limiting the ohmic losses in the stretch of cable (about 100 meters) between the tracker and the power sources.

Dhawan, S; Khanna, R; Kierstead, J; Lynn, D; Mincer, A; Musso, C; Rescia, S; Smith, H; Tipton, P; Weber, M

2008-01-01

 
 
 
 
361

Unilateral Cryptorchidism in Nigerian Sahel Bucks Criptorquidia Unilateral en Cabras Sahel Nigerianas  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Out of 1608 Nigerian Sahel male goats (bucks) examined for cryptorchidism in an abattoir, 9 (0.6%) had right unilateral cryptorchidism. The coat colour-specific prevalence was highest among the brown bucks (2.1%); and was 0.8%, 0.6%, and 0.3% among black, white, back-and-white bucks, respectively. The condition was not found among bucks with brown-and-black, brown-and-white, and multiple coat colours. The right and left testes of normal bucks and the descended testes of cryptorchid bucks had ...

Igbokwe, I. O.; Grema, H. A.; Ikpo, A. E.; Mshelbwala, F. M.; Igbokwe, N. A.

2009-01-01

362

Maximum Power Point Tracking of DC To DC Boost Converter Using Sliding Mode Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A sliding mode controller is used to estimate the maximum power point as a reference for it to track that point and force the PV system to operate in this point. In sliding mode control, the trajectories of the system are forced to reach a sliding manifold of surface, where it exhibit desirable features, in finite time and to stay on the manifold for all future time. The load is composed of a battery bank. It is obtained by controlling the duty cycle of a DC-DC converter using sliding mode...

Anusuyadevi R; Suresh Pandiarajan P; Muruga Bharathi J

2013-01-01

363

Single stage single phase active power factor corrected ?uk Topology Based AC-DC Converter  

Directory of Open Access Journals (Sweden)

Full Text Available This paper focuses on the analysis of a power factor correction (PFC converter using close loop ?uk topology. Regardless of the input line voltage and output load variations, input current drawn by the buck or buck-boost converter is always discontinuous. The Boost converter suffers from high voltage stresses across the power electronic devices. The input current in ?uk converter is comparable to boost converter’s input current. In this paper output voltage is controlled by inner current and outer voltage control loop along with power factor correction (PFC. It shows less input current THD, nearly unity power factor and better output voltage regulation of AC-DC converter under variable input voltage and output load. In this paper the relative performance between normal diode rectifier, open loop ?uk rectifier and close loop ?uk rectifier is presented. An algorithm for implementing close loop ?uk rectifier in digital domain is developed and simulated.

Md. Ismail Hossain

2014-03-01

364

Design and Implementation of Power Converters for Hybrid Wind-Solar Energy Conversion System with an Implementation of MPPT  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the design and implementation of power converters for wind conversion systems. The power converter can not only transfer the power from a wind generator, but also improve the stability and safety of the system. The proposed system consists of a Permanent magnet synchronous generator (PMSG; a DC/DC boosts converter, a bi-directional DC/DC converter and a full-bridge DC/AC inverter. The wind generator is the main power source of the system, and the battery is used for energy storage and power compensation to recover the natural irregularity of the wind power. In this paper presents a new system configuration of the front-end rectifier stage for a hybrid wind or photo voltaic energy system. The configuration allows the two sources to supply the load separately or simultaneously, depending on the availability of energy sources. The inherent nature of this cuk-scpic fused converter, additional input filters are not necessary to filter out high frequency harmonic content is determinant for the generator life span, heating issue and efficiency. The fused multi-input rectifier stage also allows maximum power from the wind and sun. When it is available an adaptive MPPT algorithm will be used for photo voltaic (PV system. Operational analysis of the roposed system, will discoursed in this paper simulation results are given to highlight the merit of the proposed circuit.

G. Sridhar Babu

2013-11-01

365

Preservation of Washed Spermatozoa of Mehsana Buck at Refrigeration Temperature  

Directory of Open Access Journals (Sweden)

Full Text Available The study was done to understand the preservation of Washed Spermatozoa of Mehsana Buck at Refrigeration temperature. The washed spermatozoa from 78 semen ejaculates, 26 each from 3 Mehsana bucks, were preserved at 4 ± 10C temperature in SM and TCFEY diluents up to 72 hours and the physical characteristics of spermatozoa were studied to assess the suitability of diluents. The individual sperm motility and live spermatozoa decreased significantly whereas abnormal spermatozoa increased significantly (P<0.05 at each 12 hrs interval of preservation in two diluents. The effect of diluents on spermatozoan characteristics was less pronounced in SM than TCFEY diluent. Among the interaction studies, stage of preservation affected the live spermatozoa and their morphology. The findings suggested superiority of SM diluent over TCFEY for preservation of Mehsana buck semen. [Vet. World 2012; 5(5.000: 294-296

V R Parmar

2012-10-01

366

Pathology of Experimental Trypanosoma evansi Infection in Savannah Brown Buck  

Directory of Open Access Journals (Sweden)

Full Text Available The pathology of experimental Trypanosoma evansi infection in Savannah Brown buck was studied using an isolate obtained from the blood of an infected camel slaughtered at Kano Abattoir, Nigeria. Gross pathological lesions observed included pale carcass with hydro peritoneum, generalized atrophy of the body fats, catarrhal enteritis, hepatomegally with bilaterally congested kidney, congested lungs with red hepatization of the liver. Histopathological lesions observed in the infected Savannah Brown buck included Zenkers necrosis of the myocardium with few mononuclear cellular infiltrations, focal areas and centrilobular necrosis of the liver, hemosiderin-laden macrophages involving the spleen and lymph nodes. There were degenerated seminiferous tubules and degenerated spermatids in the duct of the epididymis. The results of this study showed that the T. evansi isolate is pathogenic to the Savannah Brown buck.

S.A. Shehu

2006-01-01

367

Efficient Design in a DC to DC Converter Unit  

Science.gov (United States)

Space Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is no exception. This paper explores the design methods and tradeoffs that were utilized to accomplish high efficiency in the DDCU. An isolating DC to DC converter was selected for the ISS power system because of requirements for separate primary and secondary grounds and for a well-regulated secondary output voltage derived from a widely varying input voltage. A flyback-current-fed push-pull topology or improved Weinberg circuit was chosen for this converter because of its potential for high efficiency and reliability. To enhance efficiency, a non-dissipative snubber circuit for the very-low-Rds-on Field Effect Transistors (FETs) was utilized, redistributing the energy that could be wasted during the switching cycle of the power FETs. A unique, low-impedance connection system was utilized to improve contact resistance over a bolted connection. For improved consistency in performance and to lower internal wiring inductance and losses a planar bus system is employed. All of these choices contributed to the design of a 6.25 KW regulated dc to dc converter that is 95 percent efficient. The methodology used in the design of this DC to DC Converter Unit may be directly applicable to other systems that require a conservative approach to efficient power conversion and distribution.

Bruemmer, Joel E.; Williams, Fitch R.; Schmitz, Gregory V.

2002-01-01

368

Photovoltaic converters; Convertisseurs photovoltaiques  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the photovoltaic installations not connected to a classical power distribution network. Its aim is to give some basic information to the conceiver and to the user of this type of electrical and energy system. After some recalls concerning the solar potentialities on the Earth`s surface, the principles of the photovoltaic effect is presented with its elementary technological application using the semi-conductor photovoltaic cell (photon-electron conversion, materials used, conversion current, PN junction and polarization, efficiency, manufacturing technology). Then, the elements to be considered for the installation of a photovoltaic power system are analyzed (in series or parallel connection of cells, current/voltage characteristics of the generator, modeling and simulation, operation, static electrical characteristic and optimal operation, impedance adaptation, electrochemical batteries, electrolytic cells, centrifugal charges, DC/DC, DC/AC and impedance adapters etc.. (J.S.) 14 refs.

Protin, L. [Laboratoire d`electronique de puissance et d`informatique industrielle (LEPII), Universite du Havre, 76 - La Havre (France); Astier, S. [Ecole Nationale Superieure d`Electrotechnique, d`Electronique, d`Informatique et d`Hydraulique (ENSEIHT), 31 - Toulouse (France)

1997-08-01

369

High-Efficiency Isolated Boost DCDC Converter for High-Power Low-Voltage Fuel-Cell Applications  

DEFF Research Database (Denmark)

A new design approach achieving very high conversion efficiency in low-voltage high-power isolated boost dc-dc converters is presented. The transformer eddy-current and proximity effects are analyzed, demonstrating that an extensive interleaving of primary and secondary windings is needed to avoid high winding losses. The analysis of transformer leakage inductance reveals that extremely low leakage inductance can be achieved, allowing stored energy to be dissipated. Power MOSFETs fully rated for repetitive avalanches allow primary-side voltage clamp circuits to be eliminated. The oversizing of the primary-switch voltage rating can thus be avoided, significantly reducing switch-conduction losses. Finally, silicon carbide rectifying diodes allow fast diode turn-off, further reducing losses. Detailed test results from a 1.5-kW full-bridge boost dc-dc converter verify the theoretical analysis and demonstrate very high conversion efficiency. The efficiency at minimum input voltage and maximum power is 96.8%. The maximum efficiency of the proposed converter is 98%.

Nymand, Morten; Andersen, Michael A. E.

2010-01-01

370

Bryophytes of Uganda. 3. Phyllodon truncatulus (Müll. Hal.) Buck is replaced in Africa by Phyllodon truncatus (Welw. & Duby) Buck (Hypnaceae, Bryopsida).  

Digital Repository Infrastructure Vision for European Research (DRIVER)

All specimens in BM labelled Phyllodon truncatus or P. truncatulus have been examined, together with two new Uganda collections, and all African species conform to the type of P. truncatus, and all American species conform to the type of P. truncatulus. Buck’s (1987) assessment of this genus is supported, and it is confirmed that P. truncatulus does not occur in Africa.

O’shea, Brian J.

1999-01-01

371

Control of a Stand-Alone Variable Speed Wind Energy Supply System †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a simple control strategy for the operation of a variable speed stand-alone wind turbine with a permanent magnet synchronous generator (PMSG). The PMSG is connected to a three phase resistive load through a switch mode rectifier and a voltage source inverter. Control of the generator side converter is used to achieve maximum power extraction from the available wind power. Control of the DC-DC bidirectional buck-boost converter, which is connected between batteries bank and...

Hussein, Mahmoud M.; Tomonobu Senjyu; Mohamed Orabi; Wahab, Mohamed A. A.; Hamada, Mohamed M.

2013-01-01

372

ESD design for analog circuits  

CERN Document Server

This book is on high voltage and system level circuit design. It covers many challenging ESD topics related to analog circuit design for both ESD device and ESD circuits at the network level. Included is extensive discussion of analog design for DC-DC buck/boost converters, level shifters, digital-analog converters, high speed and precision power amplifiers, and system level cable specs for interface applications.

Vashchenko, Vladislav A

2010-01-01

373

Small-Signal Analysis of Single-Phase and Three-phase DC/AC and AC/DC PWM Converters with the Frequency-Shift Technique  

DEFF Research Database (Denmark)

A systematic approach to study dc/ac and ac/dc converters without the use of synchronous transformation is proposed. The use of a frequency-shift technique allows a straightforward analysis of single-phase and three-phase systems. The study of dc/ac and of ac/dc converters is reported to the study of dc/dc converters via a 50 Hz frequency-shift. The input admittance is calculated and measured for two study examples (a three-phase active rectifier and a single-phase photovoltaic inverter). These examples show that the purpose of a well designed controller for grid-connected converters is to minimize the input admittance in order to make the grid converter more robust to grid disturbance.

Blaabjerg, Frede; Aquila, A. DellÂ?

2004-01-01

374

Diode-assisted buck-boost voltage source inverters  

DEFF Research Database (Denmark)

This paper proposes buck-boost voltage source inverters with a unique X-shape diode-capacitor network inserted between inverter circuitry and dc source for producing a large voltage boost gain. Comparing with other voltage buck-boost techniques, the presented topologies with only a little more passive components can significantly enhance voltage boost capability for dc-ac inversion. With different front-end circuitries, the diode-assisted buck-boost inverters can show different operational principle and voltage boost ratio. Carefully analyzing the operational principle for the inherent energy charging and discharging processes of passive components reveals that the dc-link voltage can alternate between two levels, which therefore demonstrate the phenomena that the specified modulation schemes should note. A modulation scheme that can achieve optimized harmonic switching is first designed with symmetrical state placement in each switching sequence to avoid unnecessary voltage stress across both passive and active components. To reduce the total commutation count, the designed modulation scheme is then modified without increasing voltage stress. All theoretical findings were verified experimentally using a number of scale-down laboratory prototypes.

Gao, F.; Loh, P.C.

2007-01-01

375

Multistability and Torus Reconstruction in a DCâ??DC Converter With Multilevel Control  

DEFF Research Database (Denmark)

By virtue of their limited size and relatively low costs, multilevel dc-dc converters have come to play an important role in modern industrial power supply systems. When operating in a regime of high corrector gain, such converters can display a variety of new dynamic phenomena associated with the appearance of additional oscillatory modes. Starting in a state where four pairs of stable and unstable period-6 cycles coexist with the basic period-1 cycle, the paper describes a sequence of smooth and nonsmooth bifurcations through which the cycles and their basins of attraction transform as the output voltage is increased. The paper also describes the birth of a multilayered resonance torus through a transverse pitchfork bifurcation of the saddle cycle on an ordinary resonance torus.

Mosekilde, Erik

2013-01-01

376

Modelling, Simulation, Fabrication, Experiments and Real-Time Linear State Variable Feedback Control of Cuk Converter using Pole Placement Technique  

Science.gov (United States)

Using a suitable combination of some of the basic converter topologies representing the Buck, the Boost and the Buck-Boost converters, one may obtain some other useful dc-to-dc converters. A typical example is the cascade connection of the Boost and the Buck converter which produces the well known Cuk converter. This work emphasises on the modelling, real-time simulations, fabrication and closed-loop control of a Cuk converter. For the modelling and real time simulation, FPGA platform has been used. Small signal modelling and conventional control aspects (compensator) of Cuk converter are discussed. A 200W, 10kHz Cuk converter is designed, fabricated and tested in the laboratory. The converter model is of fourth order. The transfer function being a non-minimum phase one with two right-half plane zeroes, a limited work has been done on this. For such systems, conventional control methods are demonstrated to fail. Pole placement technique, which is envisaged to be a suitable control technique for a higher order non-minimum phase system has been adopted. Excellent correlation between off-line and real-time simulation results establishes the accuracy of the work. Agreement between open-loop results obtained from the experimental set-up under steady state vis-a-vis those obtained from simulation is also a major highlight of the paper.

Nanda, S.; Sengupta, M.; Sengupta, A.

2014-05-01

377

5kW phase-shifted full-bridge converter with current doubler using normally-off SiC JFETs designed for 98% efficiency  

DEFF Research Database (Denmark)

In this paper a 5kW step-down converter for low-voltage high-current application is presented using normally-off SiC JFETs as high voltage power switches, operating with efficiency close to 98%. Different low voltage side rectification solutions and loss estimations are also presented. As results show higher power density and efficiency can be achieved in medium- or high-power DC-DC applications by replacing silicone power devices with SiC alternatives.

Török, Lajos; Beczkowski, Szymon

2013-01-01

378

A MULTILEVEL CONVERTER WITH REDUCED NUMBER OF SWITCHES FOR FUEL CELL POWER CONDITIONING SYSTEM  

Directory of Open Access Journals (Sweden)

Full Text Available This study investigates the potentials of cascaded five and seven level converters with reduced number of switches for fuel cell power conditioning system. Fuel cells is one of the most important sources of distributed energy because of its high efficiency, high energy density, plus high reliability and long life due to few moving parts. This study proposes a suitable multilevel converter with less number switches that fulfills the required performance specifications of a fuel cell power conditioning system. The dc-dc and dc-ac converters are required to produce constant magnitude and frequency voltage from fuel cells. However Switching losses in these converters reduce overall efficiency of the system. To improve the efficiency and to use in medium and high power applications, the multilevel converter with reduced number of switches is connected as dc-ac converter. To synthesize maximum levels at the output voltage, the proposed topology is optimized for various objectives, such as the minimization of the number of switches, gate driver circuits and capacitors and blocking voltage on switches. The operation and performance of the proposed multilevel converter have been evaluated by MATLAB/SIMULINK.

K. Prasada Rao

2014-01-01

379

Results of Buck screw fusion in grade I spondylolisthesis.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The results of posterolateral screw fixation using the Buck technique performed on 24 patients with painful isthmic spondylolysis and up to grade I spondylolisthesis in the lumbar spine are reported. The average age at operation was 29 years and average follow-up was 5 years with a range of 13 months to 12 years. Operations were performed for persistent disabling low back pain. At review 21 patients were either free of pain or complained of only occasional backache and discomfort. All but two...

Bonnici, A. V.; Koka, S. R.; Richards, D. J.

1991-01-01

380

Optimization and AMS Modeling for Design of an Electrostatic Vibration Energy Harvester’s Conditioning Circuit with an Auto-Adaptive Process to the External Vibration Changes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Electrostatic transducers for vibration energy scavenging have been an object to numerous studies, but are still facing major issues relating to their conditioning circuit. One of the most popular ones uses a charge pump and a flyback circuit based on a Buck DC-DC converter (Fig. 1). A commutation between the energy accumulation in the charge pump and the recharge of the buffer capacitor Cres is assured by a switch which is the major bottleneck in the energy harvester circuit. The commutation...

Galayko, Dimitri; Basset, Philippe; Paracha, Ayyaz Mahmood

2008-01-01

 
 
 
 
381

Optimization and AMS Modeling for Design of an Electrostatic Vibration Energy Harvester's Conditioning Circuit with an Auto-Adaptive Process to the External Vibration Changes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Electrostatic transducers for vibration energy scavenging have been an object to numerous studies, but are still facing major issues relating to their conditioning circuit. One of the most popular ones uses a charge pump and a flyback circuit based on a Buck DC-DC converter (Fig. 1). A commutation between the energy accumulation in the charge pump and the recharge of the buffer capacitor Cres is assured by a switch which is the major bottleneck in the energy harvester circui...

Galayko, Dimitri; Basset, Philippe; Paracha, Ayyaz Mahmood

2008-01-01

382

Fuzzy Control of a Lead Acid Battery Charger  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, an alternative battery charging control technique based on fuzzy logic for photovoltaic (PV applications is presented. A PV module is connected to a buck type DC/DC power converter and a microcontroller based unit is used to control the lead acid battery charging voltage. The fuzzy control is used due to the simplicity of implementation, robustness and independence from the complex mathematical representation of the battery. The usefulness of this control method is confirmed by experiments.

A. DAOUD

2005-03-01

383

Analog Fixed Maximum Power Point Control for a PWM Step-downConverter for Water Pumping Installations  

DEFF Research Database (Denmark)

This paper describes a Fixed Maximum Power Point analog control used in a step-down Pulse Width Modulated power converter. The DC/DC converter drives a DC motor used in small water pumping installations, without any electric storage device. The power supply is provided by PV panels working around their maximum power point, with a fixed operating voltage value. The control circuit implementation is not only simple and cheap, but also robust and reliable. System protections and adjustments are also proposed. Simulations and hardware are reported in the paper for a 150W water pumping application system. The proposed Optimal Power Point fix voltage control system is analyzed in comparison to other complex controls.

Beltran, H.; Perez, E.

2009-01-01

384

Development of a digital solar simulator based on full-bridge converter  

Science.gov (United States)

With the development of solar photovoltaic, distribution schemes utilized in power grid had been commonly application, and photovoltaic (PV) inverter is an essential equipment in grid. In this paper, a digital solar simulator based on full-bridge structure is presented. The output characteristic curve of system is electrically similar to silicon solar cells, which can greatly simplify research methods of PV inverter, improve the efficiency of research and development. The proposed simulator consists on a main control board based on TM320F28335, phase-shifted zero-voltage-switching (ZVS) DC-DC full-bridge converter and voltage and current sampling circuit, that allows emulating the voltage-current curve with the open-circuit voltage (Voc) of 900V and the short-circuit current (Isc) of 18A .When the system connected to a PV inverter, the inverter can quickly track from the open-circuit to the maximum power point and keep stability.

Liu, Chen; Feng, Jian; Liu, Zhilong; Tong, Weichao; Ji, Yibo

2014-02-01

385

PAM inverter system with power factor corrected converter; Korikiritsu converter wo katsuyoshita PAM gata inverter system  

Energy Technology Data Exchange (ETDEWEB)

In most cases, PWM power factor corrected (PFC) converters are constructed by a diode rectifier and an active power circuit such as a boost or buck-boost chopper. Besides the PFC operation, the active power circuit can control the dc output voltage. The output voltage of the PAM inverters are controlled by varying the level of dc input voltage. A PAM method reduces the voltage and current stresses of the inverter and motors. This paper proposes a new PAM inverter system with high power factor converter to obtain a sinusoidal input current. A Proposed PAM method to reduce the torque ripple in the induction motor can be reduced a switching losses by providing a pausing interval where the switching operation stops during a part of one period. 8 refs., 15 figs., 1 tab.

Taniguchi, K.; Matano, Y.; Morizane, T.; Kimura, N. [Osaka Institute of Technology, Osaka (Japan)

1997-08-20

386

Offshore installation of welded pipe: local bucking evaluation  

Energy Technology Data Exchange (ETDEWEB)

The reeling process is widely used in offshore operations to construct the pipeline. The installation of welded pipes offers several advantages but is also a source of concern related to failure by fracture, plastic collapse and local buckling may occur. This paper investigated the effect of material geometrical parameters on the local bucking of pipes subjected to bending during the reeling process. Finite element analyses were used to evaluate buckling occurrence conditions for different geometries and materials. The model was based on the finite element method using the MITC4 shell element in the ADINA finite element program. A zone representative of the heat affected zone (HAZ) was included in the model to better represent an ERW pipe. The influence of the girth weld in the buckling response of the pipe was also simulated. The results showed that the geometry and the stress-strain curve of the material have important roles in the moment curvature response of the pipes.

Bravo, Richard E.; Cravero, Sebastian; Ernst, Hugo A.; Mantovano, Luciano [TENARIS GROUP, Campana, (Argentina)

2010-07-01

387

TAXONOMY OF PSEUDOMONAS PISCICIDA (BEIN) BUCK, MEYERS, AND LEIFSON.  

Science.gov (United States)

Hansen, A. J. (University of Idaho, Moscow), O. B. Weeks, and R. R. Colwell. Taxonomy of Pseudomonas piscicida (Bein) Buck, Meyers, and Leifson. J. Bacteriol. 89:752-761. 1965.-Twenty strains of marine bacteria showing the properties of pigmentation and icthyotoxicity were studied for selected physiological features. A quantitative taxonomic analysis with an electronic computer was performed. Eighteen species of Pseudomonas were included in the computer analysis as reference strains. The marine collection formed a homogeneous cluster, 80% similarity, and showed a 67 to 70% similarity to certain of the Pseudomonas species: P. atlantica, P. geniculata, P. synxantha, and P. taetrolens. The marine strains are treated as a phenon describing the species P. piscicida. The species was characterized by the hypothetical Median Organism concept; P. piscicida 14 corresponded most closely to the Median Organism. PMID:14273657

HANSEN, A J; WEEKS, O B; COLWELL, R R

1965-03-01

388

Taxonomy of Pseudomonas piscicida (Bein) Buck, Meyers, and Leifson1  

Science.gov (United States)

Hansen, A. J. (University of Idaho, Moscow), O. B. Weeks, and R. R. Colwell. Taxonomy of Pseudomonas piscicida (Bein) Buck, Meyers, and Leifson. J. Bacteriol. 89:752–761. 1965.—Twenty strains of marine bacteria showing the properties of pigmentation and icthyotoxicity were studied for selected physiological features. A quantitative taxonomic analysis with an electronic computer was performed. Eighteen species of Pseudomonas were included in the computer analysis as reference strains. The marine collection formed a homogeneous cluster, 80% similarity, and showed a 67 to 70% similarity to certain of the Pseudomonas species: P. atlantica, P. geniculata, P. synxantha, and P. taetrolens. The marine strains are treated as a phenon describing the species P. piscicida. The species was characterized by the hypothetical Median Organism concept; P. piscicida 14 corresponded most closely to the Median Organism.

Hansen, A. J.; Weeks, O. B.; Colwell, R. R.

1965-01-01

389

Quality Of Pe Buck Sperm Stored In Different Packaging  

Directory of Open Access Journals (Sweden)

Full Text Available AI for cattle has been develop in Indonesia in contrast, AI for small ruminants (sheep and goat are less developed. Its due to the lack of facilities, processing and packaging during storage. This research aims to compare the effectivity and efficiency of two different packaging technique (test tube and straw. Test tube and 0.25 ml mini straw were tested . Semen was obtained from adult PE buck (3 yr after collection by using artificial vagina. The fresh semen was then evaluated and diluted 5 folds with 2.9 percent Na-citrate. Diluted semen then packed in test tube and mini straw, and stored in refrigerator (100C for 7 days. Observations were done everyday on sperm motility, abnormality and percentage of live sperm. Observation were made at 370C. Observation on fresh ejaculate showed that semen has 6x 109/ml concentration, 90 percent motility, 8 percent abnormality and 95 percent live sperm. Five folds dilution reduced sperm concentration to 1.2 x 109/ml, but did not change sperm motility, abnormality and percent of live sperm. Sperm was then packed according to the treatments. Storage in both packaging did significantly reduce (P<0.01 sperm motility and percent live sperm, but not for sperm abnormality. All sperm stored in test tube were classified death at day 5 storage. However, sperm in the straw were remain live eventhough the percentages was low. It can be concluded that straw has a better result than test tube. Eventhough sperm motility was extremely low, it remains valuable for cervical insemination. (Animal Production 1(1 : 24-29 (1999.Key Words : Sperm, PE Buck, Straw, Test Tube

M Pangestu

1999-01-01

390

A Photovoltaic Power System Using a High Step-up Converter for DC Load Applications  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a power system using a high step-up converter for dc load applications. The high step-up converter adopts a boost converter with interleaved mode and a coupled inductor to raise its powering ability and increase its step-up voltage ratio, respectively. In order to increase conversion efficiency, an active clamp circuit is introduced into the proposed one to provide soft-switching features to reduce switching losses. Moreover, switches in the converter and active clamp circuit are integrated with a synchronous switching technique to reduce circuit complexity and component counts, resulting in a lower cost and smaller volume. A perturb and observe method is adopted to extract the maximum power from photovoltaic (PV arrays. Furthermore, a microchip associated with PWM IC is used to implement maximum power point tracking operation, voltage regulation and power management. Finally, a prototype PV power system with 400 V/6 A has been implemented for verifying the feasibility of the proposed PV power system. It is shown to be suitable for PV energy conversion applications when the duty ratios of switches in the dc/dc converter are less than 0.5.

Hung-Yuan Wang

2013-02-01

391

Hydrogen converters  

International Nuclear Information System (INIS)

The National Atomic Energy Commission of Argentina developed a process of 99Mo production from fission, based on irradiation of uranium aluminide targets with thermal neutrons in the RA-3 reactor of the Ezeiza Atomic Centre. These targets are afterwards dissolved in an alkaline solution, with the consequent liberation of hydrogen as the main gaseous residue. This work deals with the use of a first model of metallic converter and a later prototype of glass converter at laboratory scale, adjusted to the requirements and conditions of the specific redox process. Oxidized copper wires were used, which were reduced to elementary copper at 400 C degrees and then regenerated by oxidation with hot air. Details of the bed structure and the operation conditions are also provided. The equipment required for the assembling in cells is minimal and, taking into account the operation final temperature and the purge with nitrogen, the procedure is totally safe. Finally, the results are extrapolated for the design of a converter to be used in a hot cell. (author)

2003-11-26

392

Wavelength Converters  

DEFF Research Database (Denmark)

After a short introduction to the different requirements to and techniques for wavelength conversion, focus is on cross-gain and cross-phase modulation in SOAs and SOA based interferometers. Aspects like jitter accumulation, regeneration and conversion to the same wavelength is discussed. It is predicted that jitter accumulation can be minimised by using a 9-10 dB ratio between the signal and CW power also assuring a high extinction ratio. Using this guideline simulations show that 20 cross-gain modulation converters can be cascaded at 10 Gbit/s with only ~20 ps of accumulated jitter and an extinction ratio of ~10 dB.The regenerative capabilities of the cross-phase converters are described and verified experimentally at 20 Gbit/s, where the noise redistribution and improvement of the signal-to-noise ratio clearly is demonstrated by controlling the input power to an EDFA. In a similar experiment at 2.5 Gbit/s, the regeneration causes a reduction of the required input power to an in-line EDFA of ~6 dB for a power penalty of 1 dB at a bit error rate of 10-9. If two converters are concatenated the power requirement is reduced ~8 dB. Obviously, the power reduction allows for longer spans between in-line EDFAs.

Kloch, Allan; Hansen, Peter Bukhave

1999-01-01

393

Bucking coil implementation on PMT for active canceling of magnetic field  

International Nuclear Information System (INIS)

Aerogel and water ?herenkov detectors were employed to tag kaons for a ? hypernuclear spectroscopic experiment which used the (e,e?K+) reaction in experimental Hall C at Jefferson Lab (JLab E05-115). Fringe fields from the kaon spectrometer magnet yielded ?5 gauss at the photomultiplier tubes for these detectors. These fields, which could not be easily passively shielded, would result in a lowered kaon detection efficiency if not mitigated. A bucking coil was placed on each photomultiplier tube to actively cancel this magnetic field, thus recovering kaon detection efficiency. -- Highlights: •Bucking coil was developed to cancel a magnetic field for a photomultiplier tube. •A gain reduction of the PMT due to magnetic fields was carefully studied. •Bucking coil conditions were optimized to recover the gain of the PMT. •Bucking coils implemented in a hypernuclear experiment worked well

2013-11-21

394

Bucking coil implementation on PMT for active canceling of magnetic field  

Energy Technology Data Exchange (ETDEWEB)

Aerogel and water ?herenkov detectors were employed to tag kaons for a ? hypernuclear spectroscopic experiment which used the (e,e?K{sup +}) reaction in experimental Hall C at Jefferson Lab (JLab E05-115). Fringe fields from the kaon spectrometer magnet yielded ?5 gauss at the photomultiplier tubes for these detectors. These fields, which could not be easily passively shielded, would result in a lowered kaon detection efficiency if not mitigated. A bucking coil was placed on each photomultiplier tube to actively cancel this magnetic field, thus recovering kaon detection efficiency. -- Highlights: •Bucking coil was developed to cancel a magnetic field for a photomultiplier tube. •A gain reduction of the PMT due to magnetic fields was carefully studied. •Bucking coil conditions were optimized to recover the gain of the PMT. •Bucking coils implemented in a hypernuclear experiment worked well.

Gogami, T., E-mail: gogami@lambda.phys.tohoku.ac.jp [Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan); Asaturyan, A. [Yerevan Physics Institute (Armenia); Bono, J.; Baturin, P. [Department of Physics, Florida International University, Miami, FL 33199 (United States); Chen, C. [Department of Physics, Hampton University, Virginia 23668 (United States); Chiba, A.; Chiga, N.; Fujii, Y.; Hashimoto, O.; Kawama, D.; Maruta, T. [Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan); Maxwell, V. [Department of Physics, Florida International University, Miami, FL 33199 (United States); Mkrtchyan, A. [Yerevan Physics Institute (Armenia); Nagao, S.; Nakamura, S.N. [Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan); Reinhold, J. [Department of Physics, Florida International University, Miami, FL 33199 (United States); Shichijo, A. [Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan); Tang, L. [Department of Physics, Hampton University, Virginia 23668 (United States); Taniya, N. [Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan); Wood, S.A. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); and others

2013-11-21

395

The rape of Carrie Buck, Paul LombardoSite: DNA Interactive (www.dnai.org)  

Science.gov (United States)

Interviewee: Paul Lombardo DNAi Location:Chronicle>Trial of Carrie Buck>epilogue Carrie was raped After raping Carrie, Clarence Garland left Charlottesville rather than fulfill his promise to marry her.

2008-10-06

396

A revision of the genus Radulina W.R.Buck & B.C.Tan (Sematophyllaceae: Bryopsida)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The palaeotropic moss genus Radulina W.R.Buck & B.C.Tan is revised, resulting in the genus being reduced to four species and one variety. The following 14 names become synonyms of the oldest name in the genus, Radulina borbonica (Bél.) W.R.Buck: Hypnum hamatum Dozy & Molk., Sematophyllum subinstratum Besch., Hypnum trachyamphorum Müll.Hal., Sigmatella hamicuspis Müll.Hal. in Paris, nom. nud., Trichosteleum borbonicum var. brachycarpum Renauld & Cardot, Trichosteleum subtile Broth. & Watts,...

O’shea, Brian J.

2006-01-01

397

Comparative Studies on Reproductive Performance of Nubian and Saanen Bucks under the Climatic Conditions of Khartoum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Six mature Saanen bucks imported from the Netherlands for upgrading of local Sudanese goats and six, mature Nubian bucks were chosen from the Small Ruminant Research Centre at Kuku, Khartoum North were used. The experiment was designed to investigate the effect of climate and seasons on the mating behaviour and semen characteristics. Semen was collected by an Artificial Vagina (AV) at weekly intervals and ejaculate volume, spermatozoa motility, concentration and percentage of dead an...

Kamal; Gubartallah, A.; Ahmed, A.; Amel; Bakhiet, O.; Babiker, A.

2005-01-01

398

Aalborg Inverter - A new type of â??Buck in Buck, Boost in Boostâ? Grid-tied Inverter  

DEFF Research Database (Denmark)

This paper presents a new family of high efficiency DC/AC grid-tied inverter with a wide variation of input DC voltage. It is a kind of â??Boost in Boost, Buck in Buckâ? inverter, meaning that only one power stage works at the high frequency to achieve the minimum switching loss. Furthermore, the minimum filtering inductance in the power loop is achieved to reduce the conduction power loss whether in â??Boostâ? or â??Buckâ? mode. In theory, it can achieve higher efficiency than other inverters under the same condition of input DC voltage. The principle of operation is fully illustrated through the analysis on the equivalent circuits of a â??three-levelâ? single-phase inverter. Simulations show it has good control performance.

Wu, Weimin; Blaabjerg, Frede

2013-01-01

399

Physiological Responses of West African Dwarf Buck as Affected by Datura Stramonium Linn Seed Extract  

Directory of Open Access Journals (Sweden)

Full Text Available To evaluate the action of aqueous extract of Datura stramonium seeds on the physiological status of West African Dwarf (WAD -bucks, the effects of aqueous extract of the seed of Datura stramonium Linn was investigated for some physiological parameters in twenty (20 West African Dwarf bucks aged 12- 18 months and averaged 8.76±1.23kg for a period of 2months. The bucks were grouped into five treatments consisting four bucks and using Completely Randomized Design (CRD. The bucks were subcutaneously administered with the plant extract at a dose of 0, 0.02, 0.04, 0.06 and 0.08ml/kg bodyweight respectively. The results of the study revealed that the treated bucks had higher (p>0.05 body weight than the control but treated had lower rectal temperature than the control (p>0.05. However, the extract produced significant effect (p<0.05 on the pulse and heart rate and this may be as a result of the active principles present in the extract used for the study. Based on the findings of the present study, the aqueous extract of Datura stramonium could serve as a stimulatory agent and if properly screened using additional solvents, pharmacologically active drugs could be obtained. The significant effect produced by the aqueous extract on the animals has provided scientific justification for the ethno medicinal uses of the plant in India and South Africa.

Fatoba, T. A.

2012-12-01

400

Suppressing EMI of Switching Converters Using Self-Excitation-Chaos  

DEFF Research Database (Denmark)

A method of EMI reduction using spectral modification through self-excitation-chaos is proposed. We derived a second-order S-switching iterative map describing the dynamics of simple feedback buck switching regulator operating in continuous mode. Analysis of this map shows that chaos and bifurcations may occur at certain values of the input voltage. By making the converter operating in chaos, the simulation results demonstrate that a reduction of spectral peak and consequent spreading of the spectrum can be shown, and it will hardly influence to output voltage ripples. Keyword: Self-Excitation-Chaos,Electromagnetic interference,Spectral modification

Li, Qingnan; Rui, Xiong

2007-01-01

 
 
 
 
401

Reduction in electromagnetic interference of switching converters using self-excitation-chaos  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We derived a second-order S-switching iterative map describing the dynamics of simple feedback Buck switching regulator operating in continuous mode. Analysis of this map shows that chaos and bifurcations may occur along with the changing of values of some system parameters. By making the converter operating in chaos, the simulation results demonstrate that a reduction of spectral peak and consequent spreading of the spectrum can be shown, any desirable amount of reductio...

Li, Qingnan; Xiong, Rui; He, Ou

2011-01-01

402

Comparison of State-of-the-Art Digital Control and Analogue Control for High Bandwidth Point of Load Converters  

DEFF Research Database (Denmark)

The purpose of this paper is to present a comparison of state-of-the-art digital and analogue control for a Buck converter with synchronous rectification. The digital control scheme is based on a digital self-oscillating modulator that allows the sampling frequency to be higher than the switching frequency of the converter. Voltage mode control is used in both the analogue and digital control schemes. The experimental results show that it is possible to design a digitally controlled Buck converter that has the same performance as can be achieved using commercially available analogue control ICs. The performance of the analogue system can however be increased by using a separate operational amplifier as error amplifier. Thus analogue control is still the best option if high control bandwidth and fast transient response to load steps are important design parameters.

Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.

2008-01-01

403

Semen characteristics and sperm morphological studies of the West African Dwarf Buck treated with Aloe vera gel extract  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background: Aloe vera (Aloe barbadensis miller) is an evergreen perennial plant widely used in modern herbal practice and is often available in proprietary herbal preparations.Objective: This study was designed to investigate the semen picture and spermatozoa morphology of West African Dwarf (WAD) bucks treated with Aloe vera extract.Materials and Methods: Twelve sexually matured WAD bucks, weighing between 11 and 15 kg, were used for the study. The bucks were first used as control (pre-treat...

2011-01-01

404

A modular power electronic transformer based on a cascaded H-bridge multilevel converter  

Energy Technology Data Exchange (ETDEWEB)

In this paper a modular power electronic transformer (PET) for feeding critical loads is presented. The PE-based transformer is a multi-cellular step-down converter that can directly connect to medium voltage levels on the primary side and provide a low voltage, highly stable interface for consumer applications. The presented structure consists of three stages: a cascaded H-bridge (CHB) rectifier, an isolation stage, and an output stage. The CHB rectifier serves as an active rectifier to ensure that the input current is sinusoidal, and it converts the high AC input voltage to low DC voltages. The isolated DC/DC converters are then connected to the DC links and provide galvanic isolation between the HV and LV sides. Finally, a three-phase inverter generates the AC output with the desired amplitude and frequency. This paper introduces a new control strategy to maintain DC voltage balance among the CHB converter cells, even if the attached loads are different. The effects of voltage offsets and device mismatches on the equal load-current sharing are investigated, and an active load-current sharing method is presented to balance the load power among the parallel-output cells. The validity of the proposed controllers and the PET performance are verified by simulation and experimental results. (author)

Iman-Eini, H. [School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395-515, Tehran (Iran); G2ELab, INPG-UJF-CNRS, UMR 5269 ENSIEG, B.P. 46, F-38402 St Martin d' Heres Cedex, Grenoble (France); Farhangi, Sh. [School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395-515, Tehran (Iran); Schanen, J.-L. [G2ELab, INPG-UJF-CNRS, UMR 5269 ENSIEG, B.P. 46, F-38402 St Martin d' Heres Cedex, Grenoble (France); Khakbazan-Fard, M. [Iran Power Generation, Distribution and Transmission Management Company, Tehran (Iran)

2009-12-15

405

High-power converters for space applications  

Science.gov (United States)

Phase 1 was a concept definition effort to extend space-type dc/dc converter technology to the megawatt level with a weight of less than 0.1 kg/kW (220 lb./MW). Two system designs were evaluated in Phase 1. Each design operates from a 5 kV stacked fuel cell source and provides a voltage step-up to 100 kV at 10 A for charging capacitors (100 pps at a duty cycle of 17 min on, 17 min off). Both designs use an MCT-based, full-bridge inverter, gaseous hydrogen cooling, and crowbar fault protection. The GE-CRD system uses an advanced high-voltage transformer/rectifier filter is series with a resonant tank circuit, driven by an inverter operating at 20 to 50 kHz. Output voltage is controlled through frequency and phase shift control. Fast transient response and stability is ensured via optimal control. Super-resonant operation employing MCTs provides the advantages of lossless snubbing, no turn-on switching loss, use of medium-speed diodes, and intrinsic current limiting under load-fault conditions. Estimated weight of the GE-CRD system is 88 kg (1.5 cu ft.). Efficiency of 94.4 percent and total system loss is 55.711 kW operating at 1 MW load power. The Maxwell system is based on a resonance transformer approach using a cascade of five LC resonant sections at 100 kHz. The 5 kV bus is converted to a square wave, stepped-up to a 100 kV sine wave by the LC sections, rectified, and filtered. Output voltage is controlled with a special series regulator circuit. Estimated weight of the Maxwell system is 83.8 kg (4.0 cu ft.). Efficiency is 87.2 percent and total system loss is 146.411 kW operating at 1 MW load power.

Park, J. N.; Cooper, Randy

1991-06-01

406

Public Health Assessment for Dublin Water Supply, Dublin, Bucks County, Pennsylvania, Region 3. CERCLIS No. PAD981740004.  

Science.gov (United States)

The Dublin TCE Site (formerly the Dublin Water Supply Site) is a National Priorities List Update 10 site located at 120 Mill Street in Dublin Borough, Bucks County, Pennsylvania. During a routine drinking water survey in 1986, the Bucks County Health Depa...

1994-01-01

407

FFT Analysis of a Series Loaded Resonant Converter-Based Power Supply for Pulsed Power Applications  

International Nuclear Information System (INIS)

An impulse power supply has been designed, simulated, and tested in order to feed the primary of a high-frequency transformer. Pulse power system has been widely used for plasma applications. The operational principle of the pulse power system is that the energy from the input source is stored in the capacitor bank device through a dc-dc converter. Then, when a discharging signal is given, the stored energy is released to the load. The new family of ZCS converters is suitable for high-power applications using insulated gate bipolar transistors (IGBTs). The power converter can achieve zero switching with the aid of high-frequency transformer. The device is capable of charging a 0.1?F capacitor up to 5 kV which accounts for a charging power of 5 kJ/s. The novel control algorithm is achieved which eminently considers the nonlinear control characteristics of impulse power supply. The required charging voltage, together with the constraint on the charging time, translates into a required maximum power of 10 kW reduced in this initial version to 5 kW. The difficulty to reliably control such a power at the high-voltage side practically forbids any approach featuring a more or less stabilized DC high-voltage to be generated from a conventional 50 Hz transformer through rectification.

2009-01-01

408

The Effects of Age, Breed, Sire, Body Weight and the Ejaculate Characteristics of Rabbit Bucks  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this research is to analyse the semen of different breeds of rabbits and to determine the effects of age, breed, sire, generation and body weight on the ejaculate characteristics of rabbit bucks. Twenty rabbit bucks comprising of three breeds (New-Zealand White 8, Chinchilla 6 and Californian White 6 between the ages of 6-9 months were used to investigate the effect of age, breed, sire and generation on body weight and ejaculate characteristics of the bucks. The experiment was carried out at the Animal Science departmental farm, Ahmadu Bello University, Zaria. Parameters considered include semen colour, semen volume, semen ejaculate volume, semen concentration, semen pH, sperm motility, body weight and age. The mean for semen ejaculate volume, semen concentration, pH, sperm motility, body weight and age were 0.5 mL, 325.5x106 sperm cells/mL, 7.5, 86.6, 2.0 and 7.6% months, respectively. Age, breed and sire had (p?0.05 effect on ejaculate characteristics but breed and sire had higher significant (p<0.01 effect on body weight. However, generation had no significant effect on the body weight and ejaculate characteristics except on semen pH (p<0.05. The ejaculate characteristics of the rabbit bucks were influenced by age, breed and sire. The values obtained were within the normal standards for rabbits-bucks. New Zealand White bucks proved superior in terms of ejaculate characteristics.

G.N. Akpa

2012-06-01

409

Current Source Converters in Discontinuous Conduction Modes of Operation  

Science.gov (United States)

This work demonstrates that Current Source Rectifier (CSR) pulse-width modulation (PWM) can be successfully modified for discontinuous conduction mode (DCM). DCM is characterized by input current distortion and non-linear input to output voltage ratio. A Dead-Beat Current Injection (DBCI) PWM method is developed that ensures sinusoidal input currents and linear input to output voltage control while in DCM. A method for control analysis is proposed that enables design of the CSR closed loop voltage controller. The proposed method is simulated to show that the desired objectives are achieved at no load and very light load, where the CSR operates in an extreme DCM condition. Experimental results verify performance of the DBCI-PWM method and validate both simulation and analytical tools used to explore the capabilities of the approach. Index Terms---Active buck rectifier, Current source rectifier (CSR), current source PWM rectifier, power conversion, power converter design, power converter analysis, input power quality

Cuzner, Robert M.

410

Carrie Buck roadside marker, still imageSite: DNA Interactive (www.dnai.org)  

Science.gov (United States)

DNAi location: Chronicle>Trial of Carrie Buck>epilogue In May 2, 2002, the 75th anniversary of the Supreme Court decision on Buck v. Bell, Virginia Governor Mark Warner publicly apologized for Virginia's past involvement in eugenics. He said, "The eugenics movement was a shameful effort in which state government never should have been involved." The State of Virginia approved a roadside marker in memory of Carrie in her hometown of Charlottesville. The governors of California, Oregon, North Carolina, and South Carolina also issued apologies.

2008-10-06

411

Distributed Generation - Power Electronic Converters, Communication and Control  

Energy Technology Data Exchange (ETDEWEB)

This thesis tries to explain the changes in the control of power electronic converters that are possible by the use of communication. Many of the renewable energy sources such as photovoltaic panels are geographically dispersed. The power rating per generator is therefore typically low. If this kind of energy source should dominate an electrical grid, the number of generators must be high. There should also be means of controlling this large number of generators simultaneously and safely. The cost of safe communication may be too high compared to the power contribution of a single generator. The Internet offers a low-cost solution, but it cannot guarantee real-time properties. Similarly to the Internet itself, it is shown how communication errors can be detected and handled in a safe manner by the end-system, in this case the generator. The generator can detect a communication timeout, and change control algorithms in order to guard itself and the connected electricity grid. When necessary, it can also disconnect and work as a local standalone power supply. In order to be able to supply all kinds of loads, the generator (in this case an inverter) is primarily voltage controlled. This results in challenges concerning current distortion. The use of feed-forward for cancellation of common grid voltage harmonics is discussed, simulated and measured. An anti-islanding algorithm for voltage controlled inverters is also developed, simulated and measured in this thesis. A DC/DC-converter for optimized connection of a photovoltaic panel is built, exploiting the photovoltaic panel properties to reduce the size and the losses significantly. Although most contributions are connected to details and parts of the system, the interactions between communication and control are emphasized (author)

Hoff, Erik Stjernholm

2007-04-15

412

Experimental Assessment of Derating Guidelines Applied to Power Electronics Converters  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish En convertidores conmutados, los transistores de potencia son los componentes más vulnerables; para mejorar su confiabilidad es común el empleo de técnicas de sobre-dimensionamiento. En este artículo, la efectividad del sobredimensionamiento se valora de manera experimental, utilizando un convertido [...] r CD-CD tipo push-pull como caso de estudio, operando en tres ambientes diferentes. La confiabilidad se predijo siguiendo el procedimiento en el MIL HDBK 217F, utilizando las mediciones de las variables eléctricas y temperatura. El análisis de sensitividad indica que la temperatura tiene el mayor impacto en la confiabilidad, seguido por el ambiente y la calidad de los dispositivos. Los resultados demuestran que un proceso de sobredimensionamiento basado únicamente en las especificaciones de CD no garantiza un comportamiento adecuado. Se proponen lineamientos adicionales para aumentar la confiabilidad de los circuitos de potencia. Abstract in english Power transistors are the most vulnerable components in switching converters, and derating is usually applied to increase their reliability. In this paper, the effectiveness of derating guidelines is experimentally assessed using a push-pull DC-DC converter as a case study, operating in three differ [...] ent environments. After measuring the electrical variables and temperature, reliability was predicted following the guidelines in MIL HDBK 217F. The sensitivity analysis performed indicates that temperature has the largest impact on reliability, followed by environment and device quality. The results obtained demonstrate that a derating procedure based solely on DC ratings does not ensure an adequate performance. Therefore, additional guidelines are suggested to help increase the overall reliability obtained from a power circuit.

S. E., De León-Aldaco; J. H., Calleja-Gjumlich; H. R., Jiménez-Grajales; F. I., Chan-Puc.

413

Exact Linearization Nonlinear Neutral-Point Voltage Control for Single-Phase Three-Level NPC Converters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This letter proposes a new control scheme for the neutral-point (NP) balance in single-phase three-level NP-clamped converters. The control is addressed considering the plant under study, a nonlinear time-variant system. A quasi-exact linearization is applied allowing the application of classic control techniques. The described method is simple, general, and suitable for buck and boost topologies, as well as for inverter or rectifier operating modes under either linear or...

Cobreces, Santiago; Bordonau Farrerons, Jose?; Salaet Pereira, Juan Fernando; Bueno, Emilio J.; Rodri?guez, Francisco J.

2009-01-01

414

Design of a DC-AC Link Converter for 500w Residential Wind Generator  

Directory of Open Access Journals (Sweden)

Full Text Available As one of alternative source of renewable energy, wind energy has an excellence prospect in Indonesia, particularly in coastal and hilly areas that has potential wind to generate electricity for residential use. There is urgent need to locally develop the low cost inverter of wind generator system for residential use. Recent developments of power electronic converters and embedded computing allow improvement of power electronic converter devices that enable integration of microcontrollers in its design. In this project, an inverter circuit with suitable control scheme design was developed. The circuit was to be used with a selected topology of Wind Energy Conversion System (WECS to convert electricity generated by 500W direct-drive permanent magnet type wind generator which is typical for residential use. From single phase AC output of the generator, rectifier circuit is designed to convert AC to DC voltage. Then DC-DC boost converter was used to step up the voltage to a nominal DC voltage suitable for domestic use. The proposed inverter then will convert the DC voltage to sinusoidal AC. The duty cycle of sinusoidal Pulse-Width Modulated (SPWM signal controlling switches in the inverter was generated by a microcontroller. The lab-scale experimental rig involves simulation wind of wind generator by running geared DC motor coupled with 500W wind generator where the prototype circuit was connected at generator output. Experimental circuit produced output voltage single phase 240V sinusoidal AC voltage with frequency of 50Hz. Measured total harmonics distortion (THD of the voltage across load was 4.0% which is within limit of 5% as recommended by IEEE Standard 519-1992.

Riza Muhida

2012-12-01

415

Topological Design and Modulation Strategy for Buck-Boost Three-Level Inverters  

DEFF Research Database (Denmark)

To date, designed topologies for dc-ac inversion with both voltage-buck and boost capabilities are mainly focused on two-level circuitries with extensions to three-level possibilities left nearly unexplored. Contributing to this area of research, this paper presents the design of a number of viable buck-boost three-level inverters that can also support bidirectional power conversion. The proposed front-end circuitry is developed from the �¿uk-derived buck-boost two-level inverter, and by using the "alternative phase opposition disposition" (APOD) modulation scheme, the buck-boost three-level inverters can perform distinct five-level line voltage and three-level phase voltage switching by simply controlling the active switches located in the designed voltage boost section of the circuits. As a cost saving option, one active switch can further be removed from the voltage-boost section of the circuits by simply re-routing the gating commands of the remaining switches without influencing the ac output voltage amplitude. To verify the validity of the proposed inverters, Matlab/PLECS simulations were performed before a laboratory prototype was implemented for experimental testing.

Teodorescu, Remus; Gao, F.

2007-01-01

416

Do Wolves Affect White-Tailed Buck Harvest In Northeastern Minnesota?  

Science.gov (United States)

In early 2000 the Northern Prairie Wildlife Research Center posted this resource on wolves at their Website. "Do Wolves Affect White-Tailed Buck Harvest In Northeastern Minnesota?" summarizes wolf impacts on deer hunting in northeastern Minnesota from 1975 to 1977. The resource may be downloaded as a .zip file.

Mech, L. D.; Nelson, Michael E.

417

Making the Most of Migrant Health Dollars: How Much Bang for the Buck?  

Science.gov (United States)

The article presents a program planning model for getting the most "bang for the buck" out of migrant health services delivery in Colorado. Elements of the model offer promise as viable short-term solutions to complex care delivery problems, including overlapping manpower, inadequate hospital care linkage and information flow issues. (Author/NQ)

Gillespie, John J.; Barnett, Stephen E.