Ibekwe B.E
2014-10-01
Full Text Available The ac to dc converters’ power factors correction in ac transmission system were investigated. The studies include: phase-controlled converter; pulse width modulated (PWM converter and ac input current shaped converter. Using Fourier series, power factors of these converters were calculated and simulated using MATLAB. The resulting curves are displayed in the hard copies for practical guides in the choice of converters; and comparatively, current shaped type is the best.
Input current shaped ac-to-dc converters
1985-01-01
Input current shaping techniques for ac-to-dc converters were investigated. Input frequencies much higher than normal, up to 20 kHz were emphasized. Several methods of shaping the input current waveform in ac-to-dc converters were reviewed. The simplest method is the LC filter following the rectifier. The next simplest method is the resistor emulation approach in which the inductor size is determined by the converter switching frequency and not by the line input frequency. Other methods require complicated switch drive algorithms to construct the input current waveshape. For a high-frequency line input, on the order of 20 kHz, the simple LC cannot be discarded so peremptorily, since the inductor size can be compared with that for the resistor emulation method. In fact, since a dc regulator will normally be required after the filter anyway, the total component count is almost the same as for the resistor emulation method, in which the filter is effectively incorporated into the regulator.
Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques
Rakan Kh Antar
2013-05-01
Full Text Available This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time for ac/dc and ac/ac/dc converters at 250rpm are reduced about 79% and 89% respectively, while delay time it reduced about 69% and 64% respectively. Therefore, speed response of the dc motor is more efficient for closed loop system compared with open loop also the response of ac/ac/dc converter is better than ac/dc converter.
Input-current shaped ac to dc converters
1986-01-01
The problem of achieving near unity power factor while supplying power to a dc load from a single phase ac source of power is examined. Power processors for this application must perform three functions: input current shaping, energy storage, and output voltage regulation. The methods available for performing each of these three functions are reviewed. Input current shaping methods are either active or passive, with the active methods divided into buck-like and boost-like techniques. In addition to large reactances, energy storage methods include resonant filters, active filters, and active storage schemes. Fast voltage regulation can be achieved by post regulation or by supplementing the current shaping topology with an extra switch. Some indications of which methods are best suited for particular applications concludes the discussion.
A novel wireless power and data transmission AC to DC converter for an implantable device.
Liu, Jhao-Yan; Tang, Kea-Tiong
2013-01-01
This article presents a novel AC to DC converter implemented by standard CMOS technology, applied for wireless power transmission. This circuit combines the functions of the rectifier and DC to DC converter, rather than using the rectifier to convert AC to DC and then supplying the required voltage with regulator as in the transitional method. This modification can reduce the power consumption and the area of the circuit. This circuit also transfers the loading condition back to the external circuit by the load shift keying(LSK), determining if the input power is not enough or excessive, which increases the efficiency of the total system. The AC to DC converter is fabricated with the TSMC 90nm CMOS process. The circuit area is 0.071mm(2). The circuit can produce a 1V DC voltage with maximum output current of 10mA from an AC input ranging from 1.5V to 2V, at 1MHz to 10MHz.
Voltage source ac-to-dc converters for high-power transmitters
Cormier, R.
1990-01-01
This work was done to optimize the design of the components used for the beam power supply, which is a component of the transmitters in the Deep Space Network (DSN). The major findings are: (1) the difference in regulation between a six-pulse and a twelve-pulse converter is at most 7 percent worse for the twelve-pulse converter; (2) the commutation overlap angle of a current source converter equals that of a voltage source converter with continuous line currents; (3) the sources of uncharacteristic harmonics are identified with SPICE simulation; (4) the use of an imperfect phase-shifting transformer for the twelve-pulse converter generates a harmonic at six times the line frequency; and (5) the assumptions usually made in analyzing converters can be relaxed with SPICE simulation. The results demonstrate the suitability of using SPICE simulation to obtain detailed performance predictions of ac-to-dc converters.
Gruber, R. P. (Inventor)
1984-01-01
A dc to dc converter which can start with a shorted output and which regulates output voltage and current is described. Voltage controlled switches directed current through the primary of a transformer the secondary of which includes virtual reactance. The switching frequency of the switches is appropriately varied to increase the voltage drop across the virtual reactance in the secondary winding to which there is connected a low impedance load. A starting circuit suitable for voltage switching devices is provided.
A Novel High Performance Bridgeless Ac-Dc Boost Converter
S.M.AshrafulAlam Mohon
2016-08-01
Full Text Available A new single phase high performance bridgeless AC-DC Boost converter is proposed. The converter is made bridgeless by the use of two unidirectional switches and two diodes at the input ac side for power conversion for both positive and negative half cycle. Because of the high frequency switching, the power factor of the circuit is inherently corrected and it requires a small filter to make the input current near sinusoidal with limited THD. The significant improvement in THD makes the circuit a good choice in applications needing AC-DC conversion with power conditioning. The circuit exhibits such better performances than conventional AC-DC boost converter with variable loads at constant frequency switching with no additional control circuits. The efficiency of the circuit is also satisfactory. Analysis and simulation results of the circuit are obtained by using software simulation. The main advantage of this new AC-DC converter is its superior power quality over conventional AC-DC boost converter
DC to DC converters: operation; Hacheurs: fonctionnement
Bernot, F. [Ecole d' Ingenieurs de Tours, 37 (France)
2002-05-01
This article deals with pulse width modulation (PWM) and pulse position modulation (PPM) DC to DC converters. A tri-phase PWM converter is made of 6 simple DC/DC converters grouped together into 3 reversible converters of the same type: 1 - single-quadrant voltage lowering converters (hydraulic analogy, study with ideal elements, full scheme with input and output filters); 2 - single-quadrant voltage raising converters (hydraulic analogy, operation); 3 - two quadrants reversible converters (structure construction, quadrants of operation, reversible converter connected to a DC motor); 4 - four-quadrants reversible converters; 5 - other converters structure (current converters and converters with intermediate storage, asymmetrical converters, converters with capacitive storage, insulated converters, resonating converters, status); 6 - conclusion. (J.S.)
AC-DC PFC Converter Using Combination of Flyback Converter and Full-bridge DC-DC Converter
Moh. Zaenal Efendi
2014-06-01
Full Text Available This paper presents a combination of power factor correction converter using Flyback converter and Full-bridge dc-dc converter in series connection. Flyback converter is operated in discontinuous conduction mode so that it can serve as a power factor correction converter and meanwhile Full-bridge dc-dc converter is used for dc regulator. This converter system is designed to produce a 86 Volt of output voltage and 2 A of output current. Both simulation and experiment results show that the power factor of this converter achieves up to 0.99 and meets harmonic standard of IEC61000-3-2. Keywords: Flyback Converter, Full-bridge DC-DC Converter, Power Factor Correction.
DC-Modulated PFC Buck-Type AC/AC Converter for Light Dimming
罗方林; 叶虹
2007-01-01
Dimmers are very widely applied in theatres, cinemas, dancing-parties, auditoriums and signal systems. They are usually supplied by single-stage AC/AC converters in the past with voltage regulation technique with the disadvantages of high total harmonic distortion, low power factor and poor power transfer efficiency. This paper introduces a novel method-DC-modulation that implements DC/DC conversion technology into AC/AC converters. The DC-modulated single-stage PFC AC/AC converters effectively improved the power factor up to 0.999 and the power transfer efficiency up to 97.8 %. The experimental results verified our design and calculation. This technique will be widely used in light dimming and other industrial applications.
Fuzzy Controlled Parallel AC-DC Converter for PFC
M Subba Rao
2011-01-01
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.
Lukemire, Alan T.
1992-01-01
Dc-to-dc power-converter circuits called "forback" resemble circuits of standard configurations called "forward", "flyback", and "Cuk". Circuit employs minor modifications to existing topologies, combines advantages, while eliminating disadvantages, of older circuits.
Liwen Pan
2016-06-01
Full Text Available This paper presents an on-board vehicular battery charger that integrates bidirectional AC/DC converter and DC/DC converter to achieve high power density for application in electric vehicles (EVs. The integrated charger is able to transfer electrical energy between the battery pack and the electric traction system and to function as an AC/DC battery charger. The integrated charger topology is presented and the design of passive components is discussed. The control schemes are developed for motor drive system and battery-charging system with a power pulsation reduction circuit. Simulation results in MATLAB/Simulink and experiments on a 30-kW motor drive and 3.3-kW AC/DC charging prototype validate the performance of the proposed technology. In addition, power losses, efficiency comparison and thermal stress for the integrated charger are illustrated. The results of the analyses show the validity of the advanced integrated charger for electric vehicles.
Blaabjerg, Frede; Aquila, A. Dell; Liserre, Marco;
2004-01-01
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...
Bidirectional dc-to-dc Power Converter
Griesbach, C. R.
1986-01-01
Solid-state, series-resonant converter uses high-voltage thyristors. Converter used either to convert high-voltage, low-current dc power to lowvoltage, high current power or reverse. Taking advantage of newly-available high-voltage thyristors to provide better reliability and efficiency than traditional converters that use vacuum tubes as power switches. New converter essentially maintenance free and provides greatly increased mean time between failures. Attractive in industrial applications whether or not bidirectional capability is required.
Willis, A. E.; Gould, J. M.; Matheney, J. L.; Garrett, H. (Inventor)
1984-01-01
The object of the invention is to provide an improved converter for converting one direct current voltage to another. A plurality of phased square wave voltages are provided from a ring counter through amplifiers to a like plurality of output transformers. Each of these transformers has two windings, and S(1) winding and an S(2) winding. The S(1) windings are connected in series, then the S(2) windings are connected in series, and finally, the two sets of windings are connected in series. One of six SCRs is connected between each two series connected windings to a positive output terminal and one of diodes is connected between each set of two windings of a zero output terminal. By virtue of this configuration, a quite high average direct current voltage is obtained, which varies between full voltage and two-thirds full voltage rather than from full voltage to zero. Further, its variation, ripple frequency, is reduced to one-sixth of that present in a single phase system. Application to raising battery voltage for an ion propulsion system is mentioned.
Design and Analysis of the Main AC/DC Converter System for ITER
盛志才; 许留伟; 傅鹏
2012-01-01
A design of the main AC/DC converter system for ITER is described and the configuration of the main AC/DC converters is presented. To reduce the reactive power absorbed from the converter units, the main AC/DC converters are designed to be series-connected and work in a sequential mode. The structure of the regulator of the converter system is described. A simulation model was built up for the PSCAD/EMTDC code, and the design was validated accordingly. Harmonic analysis and reactive power calculation of the converters units are presented. The results reveal the advantage of sequential control in reducing reactive power and harmonics.
Implementation and Control of an AC/DC/AC Converter for Double Wound Flywheel Application
J. G. Oliveira
2012-01-01
Full Text Available An all-electric driveline based on a double wound flywheel, connected in series between main energy storage and a wheel motor, is presented. The flywheel works as a power buffer, allowing the battery to deliver optimized power. It also separates electrically the system in two sides, with the battery connected to the low voltage side and the wheel motor connected to the high voltage side. This paper presents the implementation and control of the AC/DC/AC converter, used to connect the flywheel high voltage windings to the wheel motor. The converter general operation and the adopted control strategy are discussed. The implementation of the AC/DC/AC converter has been described from a practical perspective. Results from experimental tests performed in the full-system prototype are presented. The prototype system is running with satisfactory stability during acceleration mode. Good efficiency and unity power factor could be achieved, based on vector control and space vector modulation.
R. Ramesh,
2014-03-01
Full Text Available Single phase ac-dc converters having high frequency isolation are implemented in buck, boost, buck-boost configuration with improving the power quality in terms of reducing the harmonics of input current. The paperpropose the circuit configuration, control mechanism, and simulation result for the single phase ac-dc converter.
Rui Li
2016-12-01
Full Text Available The AC voltage control of a DC/DC converter based on the modular multilevel converter (MMC is considered under normal operation and during a local DC fault. By actively setting the AC voltage according to the two DC voltages of the DC/DC converter, the modulation index can be near unity, and the DC voltage is effectively utilized to output higher AC voltage. This significantly decreases submodule (SM capacitance and conduction losses of the DC/DC converter, yielding reduced capital cost, volume, and higher efficiency. Additionally, the AC voltage is limited in the controllable range of both the MMCs in the DC/DC converter; thus, over-modulation and uncontrolled currents are actively avoided. The AC voltage control of the DC/DC converter during local DC faults, i.e., standby operation, is also proposed, where only the MMC connected on the faulty cable is blocked, while the other MMC remains operational with zero AC voltage output. Thus, the capacitor voltages can be regulated at the rated value and the decrease of the SM capacitor voltages after the blocking of the DC/DC converter is avoided. Moreover, the fault can still be isolated as quickly as the conventional approach, where both MMCs are blocked and the DC/DC converter is not exposed to the risk of overcurrent. The proposed AC voltage control strategy is assessed in a three-terminal high-voltage direct current (HVDC system incorporating a DC/DC converter, and the simulation results confirm its feasibility.
Model of Bi-directional Flyback Converter for Hybrid AC/DC Distribution System
Riku Pasonen
2013-12-01
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.
Mono-switch AC-DC/DC-DC converter for single-phase UPS%单相UPS的单开关AC-DC/DC-DC变换电路
李宋; 叶满园; 袁义生
2011-01-01
A mono-switch AC-DC/DC-DC converter used in single-phase UPS system is introduced,which consists of one power switch and six diodes. As both AC-DC rectifier and DC-DC booster,its operating modes and working principle are detailed. The single-cycle nonlinear control is adopted,which applies two low-speed PI regulators to control the voltage of two capacitors on DC link and a high-speed PI regulator to control the input current. Simulative results prove that,being simple and reliable,it outputs stable DC bus voltage with high input power factor and low THD.%介绍了一种应用在单相UPS系统中的新型单开关AC-DC/DC-DC变换电路,该电路由1个功率开关器件和6个二极管组成,能够实现AC/DC整流和DC/DC升压2种功能.在详细分析了该电路运行模式及工作原理的基础上,采用了单周期非线性控制理论对其进行控制,利于2个低速PI调节器对直流母线上的2个电容器电压进行控制,1个高速PI调节器对输入电流进行控制.仿真结果表明,该电路简单可靠,输入功率因数高,电流谐波失真小,可以获得稳定的正负直流母线电压.
Liu, Xiong; Wang, Peng; Loh, Poh Chiang
2011-01-01
This paper proposes an approach for DC-link second-order harmonic power cancellation in single-phase AC/DC/AC converter with reduced number of switches. The proposed six-switch converter has two bridges with three switches in each of them, where the middle switch in each bridge is shared by the AC...... on their modulation indices of the six-switch converter, and high modulation indices are proved to be feasible for second-order power cancellation in the DC-link based on the phase difference analysis. Both reduced switch numbers and DC electrolytic capacitor size can be achieved using the proposed converter...
Ac-dc Bus-interface Bi-directional Converters in Renewable Energy Systems
Dong, Dong
2012-01-01
This dissertation covers several issues related to the ac-dc bus-interface bi-directional converters in renewable energy systems. The dissertation explores a dc-electronic distribution system for residential and commercial applications with a focus on the design of an ac-dc bi-directional converter for such application. This converter is named as the â Energy Control Centerâ due to its unique role in the system. First, the impact of the unbalanced power from the ac grid, especially the ...
Compherensive Design of a 100 kW/400 V High Performance AC-DC Converter
2015-01-01
In this paper, a comprehensive design for a 100kW/400V, three-phase pulse-width modulated (PWM) AC-DC converter is presented that serves as the front-end power supply for wide-range varying active load. This power supply includes two series stages; a six-switch AC-DC boost converter and a DC-DC buck converter to regulate 400VDC at load side. The design of all inductors and capacitors is fulfilled using mathematical expressions. In addition, small signal modelling and controller design are pre...
Determination of input/output characteristics of full-bridge AC/DC/DC converter for arc welding
Stefanov, Goce; Karadzinov, Ljupco; Sarac, Vasilija; Cingoski, Vlatko; Gelev, Saso
2016-01-01
This paper describes the design and practical implementation of AC/DC/DC converter in mode of arc welding. An analysis of the operation of AC/DC/DC converter and its input/output characteristics are determined with computer simulations. The practical part is consisted of AC/DC/DC converter prototype for arc welding with output power of 3 kW and switching frequency of 64 kHz. The operation of AC/DC/DC converter is validated with experimental measurements.
Higashiguchi; Yugami; Gao; Niiyama; Sasaki; Takahashi; Ito; Nishida
2000-11-20
A frequency upshift of a short microwave pulse is generated by the interaction between a relativistic underdense ionization front and a periodic electrostatic field with a perpendicular dc magnetic field. When the dc magnetic field is applied, further frequency upshift of 3 GHz is observed with respect to an unmagnetized case which has typically a GHz range. The radiation frequency depends on both the plasma density and the strength of the dc magnetic field, i.e., the plasma frequency and the cyclotron frequency. The frequency of the emitted radiation is in reasonable agreement with the theoretical values.
Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count
Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin;
2007-01-01
This paper presents a three-level ac-dc-ac Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled...... to switch with a three-level output voltage, where the middle neutral potential is uniquely tapped from the star-point of a wye-connected capacitive filter placed before the front-end diode rectifier for input current filtering. Through careful control, the resulting converter can accurately produce...... the correct volt-sec average at its output, while simultaneously achieving inductive voltage boosting. More interestingly, these performance features are achieved with no increase in the number of semiconductor commutations, and hence no increase in switching losses. The proposed converter therefore offers...
Lukemire, Alan T.
1995-05-01
A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.
Lukemire, Alan T. (Inventor)
1993-01-01
A pulse-width modulated DC-to-DC power converter including a first inductor, i.e. a transformer or an equivalent fixed inductor equal to the inductance of the secondary winding of the transformer, coupled across a source of DC input voltage via a transistor switch which is rendered alternately conductive (ON) and nonconductive (OFF) in accordance with a signal from a feedback control circuit is described. A first capacitor capacitively couples one side of the first inductor to a second inductor which is connected to a second capacitor which is coupled to the other side of the first inductor. A circuit load shunts the second capacitor. A semiconductor diode is additionally coupled from a common circuit connection between the first capacitor and the second inductor to the other side of the first inductor. A current sense transformer generating a current feedback signal for the switch control circuit is directly coupled in series with the other side of the first inductor so that the first capacitor, the second inductor and the current sense transformer are connected in series through the first inductor. The inductance values of the first and second inductors, moreover, are made identical. Such a converter topology results in a simultaneous voltsecond balance in the first inductance and ampere-second balance in the current sense transformer.
Final design of the Korean AC/DC converters for the ITER coil power supply system
Oh, Jong-Seok, E-mail: jsoh@nfri.re.kr [ITER Korea, National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Choi, Jungwan; Suh, Jae-Hak; Choi, Jihyun [ITER Korea, National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Lee, Lacksang; Kim, Changwoo; Park, Hyungjin; Jo, Seongman; Lee, Seungyun; Hwang, Kwangcheol; Liu, Hyoyol [Dawonsys Corp., Siheung 429-450 (Korea, Republic of); Hong, Ki-Don; Sim, Dong-Joon; Lee, Jang-Soo [Hyosung Corp., Gongdeok-Dong, Seoul 121-720 (Korea, Republic of); Lee, Eui-Jae; Kwon, Yang-Hae; Lee, Dae-Yeol; Ko, Ki-Won; Kim, Jong-Min [Mobiis Corp., Yangjae-dong, Seoul 137-888 (Korea, Republic of); Song, Inho [ITER Organization, Route de Vinon sur Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); and others
2015-10-15
The final design of the ITER TF, CS, CC and VS AC/DC converters has been completed to implement ITER requirements following the detailed design and refinements of the preliminary design. The number of parallel thyristors and the rating of fuses are coordinated to keep those devices within the explosion limit even under most severe fault conditions. The impedance of the converter transformer has been optimized taking into account the energization inrush current, short circuit current, reactive power consumption and the available DC voltage. To ensure system integrity, AC/DC converters are mechanically divided into transformers, AC busbars, 6-pulse bridges, DC interconnecting busbars and DC reactors, and then all subsystems are decoupled by flexible links. To provide stable real time network communication down to the converters, a one GbE link is deployed between master controllers and local controllers. IEEE 1588 is implemented to the embedded controllers for precision time synchronization. This paper describes the detailed solutions implemented in the final design for the ITER AC/DC converters with R&D results of converter prototypes.
Optimization Control of Bidirectional Cascaded DC-AC Converter Systems
Tian, Yanjun
in different power flow directions, a bidirectional impedance control method is also proposed to unify and improve the system stability. Control system type number is also analyzed in this thesis, then a symmetric proportional control method for the two stage cascaded converter is proposed to reduce the dc...
Modelling and analysis of current-programmed ac/dc converters
Tymerski, R. P. E.; Daly, K. C.
1985-03-01
Current-programmed dc/dc converters operating at a fixed switching frequency are analyzed using state-space averaged modeling. For converters operating in the continuous conduction mode, general closed form expressions that describe the dynamic ac small signal characteristics of the converter are obtained. A reduced order model is used to derive the control current input-to-output voltage, audio susceptibility and output impedance small signal ac transfer functions for the ideal buck, boost, and buck-boost converters operating in the continuous conduction model. It is shown that state-space averaging can correctly predict instability on the buck converter. Current-programmed converters operating in the discontinuous conduction mode are addressed, showing that the transfer functions are represented by a finite pole and a zero at infinity. Instability is predicted for the buck converter when an external ramp is omitted and the output-to-input voltage ratio is greater than or equal to two-thirds.
Multiple DC, single AC converter with a switched DC transformer
Donnelly, Matthew K.; Hammerstrom, Donald J.
1997-01-01
The invention is an improvement of the PASC inverter, wherein the improvements include the reduction from two shorting gates per transformer to one shorting gate per transformer and replacement of active control of the shorting gate with passive control of the shorting gate. Further advantages are obtained through the use of anti-parallel gate sets.
A Switched Capacitor Based AC/DC Resonant Converter for High Frequency AC Power Generation
Cuidong Xu
2015-09-01
Full Text Available A switched capacitor based AC-DC resonant power converter is proposed for high frequency power generation output conversion. This converter is suitable for small scale, high frequency wind power generation. It has a high conversion ratio to provide a step down from high voltage to low voltage for easy use. The voltage conversion ratio of conventional switched capacitor power converters is fixed to n, 1/n or −1/n (n is the switched capacitor cell. In this paper, A circuit which can provide n, 1/n and 2n/m of the voltage conversion ratio is presented (n is stepping up the switched capacitor cell, m is stepping down the switching capacitor cell. The conversion ratio can be changed greatly by using only two switches. A resonant tank is used to assist in zero current switching, and hence the current spike, which usually exists in a classical switching switched capacitor converter, can be eliminated. Both easy operation and efficiency are possible. Principles of operation, computer simulations and experimental results of the proposed circuit are presented. General analysis and design methods are given. The experimental result verifies the theoretical analysis of high frequency AC power generation.
DSP Based Control Implementation of an AC/DC Converter with Improved Input Current Distortion
WISUTMETHEEKORN, P.
2011-05-01
Full Text Available This paper presents a digital signal processor based control of an AC/DC converter with nearly unity power factor. Normally, the output voltage of a single-phase AC/DC converter comprises a voltage ripple with twice line-frequency. This affects the voltage control loop and leads to the converter input current distortion. The purposed method is designed to avoid the effect of the output voltage ripple. To verify the proposed control method, MATLAB/Simulink is used for system simulation. A hardware prototype is setup. A low cost digital signal processing chip dsPIC30F4011 is employed as a digital controller to control a CUK AC/DC converter. The converter specifications are 48V output voltage and 250W output power. From the simulation and the experimental results shown that the input current distortion of the purposed system is reduced and lower than the AC/DC converter that controlled by the conventional proportional-integral controller.
Qin, Zian; Loh, Poh Chiang; Blaabjerg, Frede
2015-01-01
ulation schemes can significantly change the performance of a power converter in steady state, and they have been extensively studied, but mostly directed to three-phase topologies, where triplen offsets are added. Single-phase systems, including ac-dc-ac systems, are less widely pursued, even...... among their switches, while keeping their dc-link voltages low. Single points of failure are thus minimized, allowing the converters to have longer lifetimes. Simulation and experimental results have demonstrated the intended performances and hence verifying the idea....
Zigzag Connected Autotransformer-Based 24-pulse AC-DC Converter
Xiao-qiang, Chen; Hao, Qiu
2015-02-01
In this paper, a zigzag connected autotransformer-based 24-pulse AC-DC converter is designed, modeled and simulated to feed direct torque controlled induction motor drives. Winding arrangements and parameters of the autotransformer and interphase reactor are given. Moreover, the design procedure of the autotransformer is modified to make it suitable for retrofit applications. Simulation results indicate that the system is capable of eliminating up to 21st harmonics in the ac mains current. The effect of load variation and load character is also studied to demonstrate the performance and effectiveness of the proposed 24-pulse converters. A set of power quality indices at ac mains and dc side are presented to compare the performance of 6-, 12- and 24-pulse converters.
Transformerless DC-DC Converter Using Cockcroft-Walton Voltage Multiplier to Obtain High DC Voltage
Meghana G Naik,
2014-11-01
Full Text Available In the present scenario the use of transformer for high voltages in converter circuit reduces the overall operating efficiency due to leakage inductance and use of transformer also increases the operational cost. . Therefore the proposed system is implemented with transformer less DC-DC converter so as to obtain high DC voltage with the use of nine stage Cockcroft-Walton (CW voltage multiplier. The proposed converter operates in CCM (continuous conduction mode, so that the converter switch stress, the switching losses are reduced. The DC voltage at the input of the proposed model is low and is boosted up by boost inductor (Ls in DC-DC converter stage and performs inverter operation. The number of stages in CW-voltage multiplier circuit is applied with low input pulsating DC (AC Voltage voltage where it is getting converted to high DC output voltage. The proposed converter switches operates at two independent frequencies, modulating (fsm andalternating (fsc frequency. The fsm operates at higher frequency of the output while the fsc operates at lower frequency of the desired output voltage ripple and the output ripples can be adjusted by the switch Sc1 and Sc2. The regulation of the output voltage is achieved by controlling the Duty ratio.The simulation is carried over by the MATLABSIMULINK.
Compherensive Design of a 100 kW/400 V High Performance AC-DC Converter
Ghasem Esfandiari
2015-01-01
Full Text Available In this paper, a comprehensive design for a 100kW/400V, three-phase pulse-width modulated (PWM AC-DC converter is presented that serves as the front-end power supply for wide-range varying active load. This power supply includes two series stages; a six-switch AC-DC boost converter and a DC-DC buck converter to regulate 400VDC at load side. The design of all inductors and capacitors is fulfilled using mathematical expressions. In addition, small signal modelling and controller design are presented in order to raise the design efficiency of the proposed converter. Also, due to the high power application, improved soft-switching techniques are applied. Furthermore, systematic approach to design an input EMI filter for DC-DC converter is explained. The simulation results performed by PSCAD software show that high performance of the proposed power supply is obtained in terms of stability, high power factor, high efficiency and low total harmonic distortion (THD.
Emissions Tests Of Two Dc-To-Dc Converters
Mclyman, W. T.
1992-01-01
Report describes tests to characterize unwanted electric and magnetic fields, at frequencies up to few megahertz, radiated by two dc-to-dc converters, one 20-kHz square-wave converter; the other, a 33-kHz sine-wave converter. Part of effort to develop "quiet" power converter for use aboard spacecraft. Converter required to interfere minimally with delicate instruments measuring electric and magnetic fields.
Bifaretti, Steffano; Zanchetta, Pericle; Iov, Florin
2008-01-01
The paper proposes a novel power conversion system for Universal and Flexible Power Management (UNIFLEX-PM) in Future Electricity Network. Its structure is based on a back-to-back three-phase AC-DC 7-level converter; each AC side is connected to a different PCC, representing the main grid and....../or various distributed generation systems. Effective and accurate power flow control is demonstrated through simulation in Matlab- Simulink environment on a model based on a two-port structure and using a Predictive Control technique. Control of different Power flow profiles has been successfully tested...
DOUBLE-BOOST DC-AC CONVERTER WITH SLIDING-MODE CONTROL FOR PORTABLE AUDIO
Bolten Maizonave, Gert; Andersen, Michael Andreas E.; Kjærgaard, Claus;
2009-01-01
The double-boost topology is studied for operation as a dc-ac converter and single stage audio amplifier. A sliding-mode controller is designed in order to achieve fast enough response for the whole audio frequency range. Symmetric, asymmetric and interleaved operation modes are analyzed....
Lu, Xiaonan; Guerrero, Josep M.; Teodorescu, Remus
2011-01-01
With the penetration of renewable energy in modern power system, microgrid has become a popular application worldwide. In this paper, parallel-connected bidirectional converters for AC and DC hybrid microgrid application are proposed as an efficient interface. To reach the goal of bidirectional...
Hierarchical Control of Parallel AC-DC Converter Interfaces for Hybrid Microgrids
Lu, Xiaonan; Guerrero, Josep M.; Sun, Kai;
2014-01-01
In this paper, a hierarchical control system for parallel power electronics interfaces between ac bus and dc bus in a hybrid microgrid is presented. Both standalone and grid-connected operation modes in the dc side of the microgrid are analyzed. Concretely, a three-level hierarchical control syst...... the three control levels is developed in order to adjust the main control parameters and study the system stability. Experimental results of a 2×2.2 kW parallel ac-dc converter system have shown satisfactory realization of the designed system.......In this paper, a hierarchical control system for parallel power electronics interfaces between ac bus and dc bus in a hybrid microgrid is presented. Both standalone and grid-connected operation modes in the dc side of the microgrid are analyzed. Concretely, a three-level hierarchical control system...... is implemented. In the primary control level, the decentralized control is realized by using the droop method. Local ac current proportional-resonant controller and dc voltage proportional-integral controller are employed. When the local load is connected to the dc bus, dc droop control is applied to obtain...
Protection sequence of AC/DC converters for ITER PF MAGNET coils
Oh, Byung Hoon; Hwang, Churl Kew; Lee, Kwang Won; Jin, Jeong Tae; Chang, Sae Sik; Oh, Jong Seok; Choi, Jung Wan; Suh, Jae Hak [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Tao, Jun; Song, In Ho [ITER Organization, Paul Lez Durance (France)
2010-06-15
The protection sequence of an AC/DC converter for an ITER PF coil system is developed in this study. Possible faults in the coil system are simulated and the results reflected in the design of a sequence to protect the coil and converter. The inductances of the current sharing reactors and thyristor numbers in parallel with the bridge arms are optimized with the designed protection sequence
A new DC/AC boost transformerless converter in application of photovoltaic power generation
Wei, Mo; Loh, Poh Chiang; Blaabjerg, Frede
2011-01-01
This paper presents a new DC/AC boost transformerless converter in the applications of photovoltaic (PV) power generation. A new circuit topology of single phase full bridge power inverter with additional DC/DC boost stage is proposed. The proposed topology overcomes two commonly existing...... shortcomings of transformerless PV system: namely one, the voltage generated sometimes low and insufficient to fulfill the load requirement; and two, there always leakage current flowing through parasitic capacitance between PV panel and ground. This configuration helps to boost the voltage at the PV side...
Modelling and Control Design of a Dual Buck-Boost AC/DC Converter Used in the DC Nano-Grid
Wu, Weimin; Liu, Yuan; Wang, Houqing;
2016-01-01
like the low voltage AC power system. In this paper, a dual Buck-Boost AC/DC converter for use in the united grounding configuration based DC Nano-grid with three terminal outputs is proposed. It will be much easy to construct an efficient DC Nano-grid based on the existing low AC power system by using......Due to widely used DC characterized loads and more distributed power generation sources, the DC Nano-grid becomes more and more popular and seen as an alternative to the AC-grid in future. For the safety considerations, the DC Nano-grid should provide reliable grounding for the residential loads...... the proposed converter. The working principle of this converter and the system modeling are presented in detail. Simulations are carried out to verify the theoretical analysis....
Padmanaban Sanjeevikumar
2008-01-01
Full Text Available This paper presents an artificial neural network (ANN based approach to tune the parameters of the cascaded d-q axis controller for an AC-DC-AC converter without dc link capacitor. The proposed converter uses the cascaded d-q axis controller on the rectifier side and space vector pulse width modulation on the inverter side. The feed-forward ANN with the error back-propagation training is employed to tune the parameters of the cascaded d-q axis controller. The converter topology provides simple commutation procedure with reduced number of switches and has additional advantages such as good voltage transfer ratio, four quadrant operation, unity power factor, no DC link capacitor and less THD in both the line and load sides. Simulation results closely match with theoretical analysis.
Khairy Sayed
2016-07-01
Full Text Available This paper presents the control and simulation of an electric vehicle (EV charging station using a three-level converter on the grid-side as well as on the EV-side. The charging station control schemes with three-level AC/DC power conversion and a bidirectional DC/DC charging regulator are described. The integration of EVs to the power grid provides an improvement of the grid reliability and stability. EVs are considered an asset to the smart grid to optimize effective performance economically and environmentally under various operation conditions, and more significantly to sustain the resiliency of the grid in the case of emergency conditions and disturbance events. The three-level grid side converter (GSC can participate in the reactive power support or grid voltage control at the grid interfacing point or the common coupling point (PCC. A fuzzy logic proportional integral (FL-PI controller is proposed to control the GSC converter. The controllers used are verified and tested by simulation to evaluate their performance using MATLAB/SIMULINK. The comparison of a PI-controller and a PI-Fuzzy controller for the EV charging station shows the effectiveness of the proposed FL-PI controller over conventional PI controller for same circuit operating conditions. A good performance for PI-Fuzzy in terms of settling time and peak overshoot can observed from the simulation results.
Efficient Design in a DC to DC Converter Unit
Bruemmer, Joel E.; Williams, Fitch R.; Schmitz, Gregory V.
2002-01-01
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.
Nonlinear control of voltage source converters in AC-DC power system.
Dash, P K; Nayak, N
2014-07-01
This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations.
A new optimum topology switching dc-to-dc converter
Cuk, S.; Middlebrook, R. D.
1977-01-01
A novel switching dc-to-dc converter is presented, which has the same general conversion property (increase or decrease of the input dc voltage) as does the conventional buck-boost converter, and which offers through its new optimum topology higher efficiency, lower output voltage ripple, reduced EMI, smaller size and weight, and excellent dynamic response. One of its most significant advantages is that both input and output current are not pulsating but are continuous (essentially dc with small superimposed switching current ripple), thus resulting in a close approximation to the ideal physically nonrealizable dc-to-dc transformer. The converter retains the simplest possible structure with the minimum number of components which, when interconnected in its optimum topology, yield the maximum performance.
Enhanced DC-Link Capacitor Voltage Balancing Control of DC–AC Multilevel Multileg Converters
Busquets-Monge, Sergio; Maheshwari, Ram Krishan; Nicolas-Apruzzese, Joan
2015-01-01
This paper presents a capacitor voltage balancing control applicable to any multilevel dc–ac converter formed by a single set of series-connected capacitors implementing the dc link and semiconductor devices, such as the diode-clamped topology. The control is defined for any number of dc......-link voltage levels and converter legs (for single-phase and multiphase systems), guaranteeing the capacitor voltage control for any modulation index value and load (from idle mode to full power). The associated control loop small-signal transfer function is presented, from which optimum compensator design...... guidelines are derived. The improvement in control performance is verified through simulation and experiments comparing with a previous balancing control strategy in a four-level three-phase dc–ac conversion system. The satisfactory control performance is also verified through simulation in a four-level five...
Vector control of three-phase AC/DC front-end converter
J S Siva Prasad; Tushar Bhavsar; Rajesh Ghosh; G Narayanan
2008-10-01
A vector control scheme is presented for a three-phase AC/DC converter with bi-directional power ﬂow capability. A design procedure for selection of control parameters is discussed. A simple algorithm for unit-vector generation is presented. Starting current transients are studied with particular emphasis on high-power applications, where the line-side inductance is low. A starting procedure is presented to limit the transients. Simulation and experimental results are also presented.
SCM Handbooks for dc-to-dc Converters
Lee, F.; Mohmoud, M.; Yu, Y.
1984-01-01
Two documents aid in design of control modules for dc-to-dc converters. Features of SCM include: Adaptive stability, power component stress limiting, implementation of various control laws, unified design approach. Analysis and quidelines contained in handbooks enable engineer to design SCM circuit and confidently predict resulting overall performance.
Tian, Yanjun; Chen, Zhe; Deng, Fujin;
2015-01-01
Two stage cascaded converters are widely used in DC/AC hybrid systems to achieve the bidirectional power transmission. The topology of dual active bridge cascaded with inverter (DABCI) is commonly used in this application. This paper proposes a coordinative control method for DABCI and it’s able...... to reduce the DC-link voltage fluctuation between the DAB and inverter, then reduce the stress on the switching devices, as well as improve the system dynamic performance. In the proposed control method, the DAB and inverter are coordinated to control the DC-link voltage and the power......, and this responsibility sharing control can effectively suppress the impact of the power variation on the DC-link voltage, without sacrificing stability. The proposed control method is also effective for DABCI in unidirectional power transmission. The effectiveness of the propose control has been validated by both...
Dc-To-Dc Converter Uses Reverse Conduction Of MOSFET's
Gruber, Robert P.; Gott, Robert W.
1991-01-01
In modified high-power, phase-controlled, full-bridge, pulse-width-modulated dc-to-dc converters, switching devices power metal oxide/semiconductor field-effect transistors (MOSFET's). Decreases dissipation of power during switching by eliminating approximately 0.7-V forward voltage drop in anti-parallel diodes. Energy-conversion efficiency increased.
A feed-forward controlled AC-DC boost converter for biomedical implants.
Jiang, Hao; Lan, Di; Lin, Dahsien; Zhang, Junmin; Liou, Shyshenq; Shahnasser, Hamid; Shen, Ming; Harrison, Michael; Roy, Shuvo
2012-01-01
Miniaturization is important to make implants clinic friendly. Wireless power transfer is an essential technology to miniaturize implants by reducing their battery size or completely eliminating their batteries. Traditionally, a pair of inductively-coupled coils operating at radio-frequency (RF) is employed to deliver electrical power wirelessly. In this approach, a rectifier is needed to convert the received RF power to a stable DC one. To achieve high efficiency, the induced voltage of the receiving coil must be much higher than the turn-on voltage of the rectifying diode (which could be an active circuit for low turn-on voltage) [1]. In order to have a high induced voltage, the size of the receiving coil often is significantly larger than rest of the implant. A rotating magnets based wireless power transfer has been demonstrated to deliver the same amount of power at much lower frequency (around 100 Hz) because of the superior magnetic strength produced by rare-earth magnets [2]. Taking the advantage of the low operating frequency, an innovative feed-forward controlled AC to DC boost converter has been demonstrated for the first time to accomplish the following two tasks simultaneously: (1) rectifying the AC power whose amplitude (500 mV) is less than the rectifier's turn-on voltage (1.44 V) and (2) boosting the DC output voltage to a much higher level (5 V). Within a range, the output DC voltage can be selected by the control circuit. The standard deviation of the output DC voltage is less than 2.1% of its mean. The measured load regulation is 0.4 V/kΩ. The estimated conversion efficiency excluding the power consumption of the control circuits reaches 75%. The converter in this paper has the potential to reduce the size of the receiving coil and yet achieve desirable DC output voltage for powering biomedical implants.
Wind-powered asynchronous AC/DC/AC converter system. [for electric power supply regulation
Reitan, D. K.
1973-01-01
Two asynchronous ac/dc/ac systems are modelled that utilize wind power to drive a variable or constant hertz alternator. The first system employs a high power 60-hertz inverter tie to the large backup supply of the power company to either supplement them from wind energy, storage, or from a combination of both at a preset desired current; rectifier and inverter are identical and operate in either mode depending on the silicon control rectifier firing angle. The second system employs the same rectification but from a 60-hertz alternator arrangement; it provides mainly dc output, some sinusoidal 60-hertz from the wind bus and some high harmonic content 60-hertz from an 800-watt inverter.
"Assessment of Potentially-Efficient DC-AC Converter Architectures"
Chapman, Jamie
2004-04-29
Two alternate and potentially-efficient power electronic architectures are assessed and compared with a conventional, three-phase, voltage-source converter. The comparisons are in terms of a 750 kVA converter as might be used with a variable-speed wind turbine or a photovoltaic array, The two architectures are projected to cost 1.15 and 1.39 times the comparable (factory) cost of the conventional system. However the present value of the recovered energy stream may justify the added cost.
Design of AC-DC Grid Connected Converter using Multi-Objective Optimization
Piasecki Szymon
2014-05-01
Full Text Available Power electronic circuits, in particular AC-DC converters are complex systems, many different parameters and objectives have to be taken into account during the design process. Implementation of Multi-Objective Optimization (MOO seems to be attractive idea, which used as designer supporting tool gives possibility for better analysis of the designed system. This paper presents a short introduction to the MOO applied in the field of power electronics. Short introduction to the subject is given in section I. Then, optimization process and its elements are briefly described in section II. Design procedure with proposed optimization parameters and performance indices for AC-DC Grid Connected Converter (GCC interfacing distributed systems is introduced in section III. Some preliminary optimization results, achieved on the basis of analytical and simulation study, are shown at each stage of designing process. Described optimization parameters and performance indices are part of developed global optimization method dedicated for ACDC GCC introduced in section IV. Described optimization method is under development and only short introduction and basic assumptions are presented. In section V laboratory prototype of high efficient and compact 14 kVA AC-DC converter is introduced. The converter is elaborated based on performed designing and optimization procedure with the use of silicon carbide (SiC power semiconductors. Finally, the paper is summarized and concluded in section VI. In presented work theoretical research are conducted in parallel with laboratory prototyping e.g. all theoretical ideas are verified in laboratory using modern DSP microcontrollers and prototypes of the ACDC GCC.
Isolated single-stage high power factor AC/DC converter
王卫; 贲洪奇; 高国安
2001-01-01
The problem of harmonic pollution has brought wide attention with the increase of power customers. The adoption of the technology of active power factor correction (APFC) with advanced high frequency power converter is a more efficient solution to the problem of harmonic pollution. A single-stage isolated high power factor AC/DC converter, which features wide range DC output, high power factor, lower harmonic pollution in input current, and phase-shift PWM full-bridge circuit can achieve soft switching. The principle of the circuit topology and the reasons of voltage surges across the power switch are analyzed. Experiment results illustrate that this circuit has the advantages of high power factor and lower harmonic distortion.
Single-stage PFC ac-dc converters
Dorin Cismasiu
2009-10-01
Full Text Available For single-phase applications, two stagepower factor correction (PFC rectifiers are typicalapproach used to achieve high power factor and fastoutput regulation. In low power area this method is tocostly. It is possible to construct a converter containinga single transistor which accomplish above mentionedfunctions. This paper highlights topological and designrequirements of single-stage high quality rectifiers.Experimental waveforms confirm the imposed mode ofoperation.
An isolated bridgeless AC-DC PFC converter using a LC resonant voltage doubler rectifier
Lee, Sin-woo; Do, Hyun-Lark
2016-12-01
This paper proposed an isolated bridgeless AC-DC power factor correction (PFC) converter using a LC resonant voltage doubler rectifier. The proposed converter is based on isolated conventional single-ended primary inductance converter (SEPIC) PFC converter. The conduction loss of rectification is reduced than a conventional one because the proposed converter is designed to eliminate a full-bridge rectifier at an input stage. Moreover, for zero-current switching (ZCS) operation and low voltage stresses of output diodes, the secondary of the proposed converter is designed as voltage doubler with a LC resonant tank. Additionally, an input-output electrical isolation is provided for safety standard. In conclusion, high power factor is achieved and efficiency is improved. The operational principles, steady-state analysis and design equations of the proposed converter are described in detail. Experimental results from a 60 W prototype at a constant switching frequency 100 kHz are presented to verify the performance of the proposed converter.
Triple voltage dc-to-dc converter and method
Su, Gui-Jia
2008-08-05
A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.
Hysteresis Current Control Based Shunt Active Power Filter for Six Pulse Ac/Dc Converter
Rakesh Kumar Pandey
2017-02-01
Full Text Available In this paper the simulation of Shunt Active power Filter using P-Q theory and PI controller has been presented. This SAPF compensates the harmonic currents drawn by three phase six pulse AC/DC converter. The process of compensation is done by calculating the instantaneous reactive power losses using p-q theory and the PI controller to reduce the ripple voltage of the dc capacitor of the PWM-VSI. This approach is different from conventional approach and provides very effective solution. In this simulation we use hysteresis band current controller (HCC for switching the VSI inverter. The simulation has been done for both steady state and transient conditions
Gao Chao
2008-01-01
This letter studies and analyzes the working features of main circuit of tri-level boost Power Factor Correct (PFC) converter and the advantages of tri-level switch converter in aspects of bearing high-voltage of power components,overall system loss and magnetic component selection based upon the single-level boost PFC switch converter. Besides,relying on the application of mi-croprocessor in power converter technology and DSP (Digital Signal Processing) chip's strong cal-culating capacity,the letter presents the adoption of modified scheme of tri-level boost PFC converter under the control of predictive control algorithm. Moreover,the operating principle and control method are specified,the results of circuit test and analysis are provided and the advantages of pre-dictive control technology-based multi-level boost PFC converter is verified.
Qin, Zian; Loh, Poh Chiang; Blaabjerg, Frede
2015-01-01
. With the SVPWM or DPWM proposed in literatures, the generation of the references is phase voltage based. But the phase voltages actually cannot be controlled directly by the PWM converter, since they can be influenced by both of terminal voltages and the load network while the PWM converter can only control...
P. Gopal,
2015-11-01
Full Text Available The main objective of this concept is to examine the operation of fundamental buck-based three-phase singlestage ac–dc full-bridge converters. In this concept, the operation of this fundamental converter is explained and analyzed, and a procedure for the design of its key components is derived and demonstrated with an example and general concluding remarks comparing Buck-Based and Boost Based three Phase single-stage AC to DC full Bridge converters are made.
Cuk, S.; Middlebrook, R. D.
1977-01-01
A method for modelling switching converters in the discontinuous conduction mode is developed, whose starting point is the unified state-space representation, and whose end result is a complete linear circuit model which correctly represents all essential features, namely, the input, output, and transfer properties (static dc as well as dynamic ac small signal). While the method is generally applicable to any switching converter operating in the discontinuous conduction mode, it is extensively illustrated for the three common power stages (buck, boost, and buck-boost). The results for these converters are then easily tabulated owing to the fixed equivalent circuit topology of their canonical circuit model.
Investigation of AC/DC Converters with PFC and Output Isolation Diodes
Mihail H. Antchev,
2014-02-01
Full Text Available This paper presents computer simulation and experimental results of a research on two parallel connected single phase AC/DC converters with power factor correction and control scheme realized by L4981A controller. The analysis is focused on: power factor and harmonic distortion of the grid current; transient process of settlement of the steady state of the output voltage and its pulsations; output currents sharing at initial start and steady state.
An overview of power electronics applications in fuel cell systems: DC and AC converters.
Ali, M S; Kamarudin, S K; Masdar, M S; Mohamed, A
2014-01-01
Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter.
A New Bidirectional AC-DC Converter Using a Matrix Converter Topology%车用新型AC-DC矩阵式变换器
徐壮; 殷冠贤; 徐殿国
2011-01-01
The expansion of automotive electronic system and the disadvantage of the conventional rectifier should not be ignored.To achieve unity power factor and complete the step-down rectification in single stage,this paper presents a new type of AC-DC matrix converter with 42V for automotives.It removed the impact of harmonics which is caused by the dead time and reduced the cost of the system.In this paper,the modulation strategy of AC-DC matrix converter derived from that of three-phase – three-phase matrix converter and the methods of commutation are studied.The optimized modulation strategy named AV method is used to control the switch-state.The four-step commutation strategy is a solution of the risks for short circuit,open circuit and the dead-time problem.The experimental results based on DSP system and the simulation results demonstrate the validity and effectiveness of the system.%针对车用电子系统容量扩大和传统PWM整流器缺点问题,为实现输入单位功率因数和一级降压整流,去除死区时间引起的谐波带来的影响,本文提出一种新型基于42V PowerNet的车用双向AC-DC矩阵变换器。在基于三相-三相矩阵变换器理论基础上,推演出AC-DC矩阵变换器的整流调制策略,并研究了开关序列和换相的方法,采用优化AV法调制策略来控制整流器。运用四步换流策略解决了开关换相存在的短路、断路风险和死区时间问题,仿真和实验结果验证了车用新型AC-DC矩阵式整流器的有效性和正确性。
Converter DC/AC Multilevel of Three Cells: Modeling and Simulation
Julián Peláez-Restrepo
2013-11-01
Full Text Available This paper presents a three-cell converter DC / AC. Multilevel topologies are attracting attention in the industry, obtained as a ripple on the state variables much smaller, and reduces stress on the switching devices. The topology used in this work is known in the technical literature as floating capacitor multilevel inverter, which imposes the challenge of balancing the voltage across each cell switching using floating capacitors, besides obtaining a sinusoidal signal regulated. The paper presents the averaged model of the inverter, and results obtained through simulation.
Abdollahi, Rohollah
2012-12-01
This paper presents a pulse doubling technique in a 12-pulse ac-dc converter which supplies direct torque controlled motor drives (DTCIMDs) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant changes in the installations and yields in harmonic reduction in both ac and dc sides. The 12-pulse rectified output voltage is accomplished via two paralleled six-pulse acdc converters each of them consisting of three-phase diode bridge rectifiers. An autotransformer is designed to supply the rectifiers. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. Independent operation of paralleled diode-bridge rectifiers, i.e. dc-ripple re-injection methodology, requires a Zero Sequence Blocking Transformer (ZSBT). Finally, a tapped interphase reactor is connected at the output of ZSBT to double the pulse numbers of output voltage up to 24 pulses. The aforementioned structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse, 12-pulse, and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 5% for the proposed topology at various loads.
Full wave dc-to-dc converter using energy storage transformers
Moore, E. T.; Wilson, T. G.
1969-01-01
Full wave dc-to-dc converter, for an ion thrustor, uses energy storage transformers to provide a method of dc-to-dc conversion and regulation. The converter has a high degree of physical simplicity, is lightweight and has high efficiency.
Janaína G. Oliveira
2011-01-01
Full Text Available The integration of a flywheel as a power handling can increase the energy storage capacity and reduce the number of battery charge/discharge cycles. Furthermore, the ability of recovering energy of the vehicle during breaking can increase the system efficiency. The flywheel-based all-electric driveline investigated here has its novelty in the use of a double-wound flywheel motor/generator, which divides the system in two different voltage levels, enhancing the efficiency of the electric driveline. The connection of two AC electrical machines (i.e., the flywheel and the wheel motor with different and variable operation frequency is challenging. A power matching control applied to an AC/DC/AC converter has been implemented. The AC/DC/AC converter regenerates the electric power converted during braking to the flywheel machine, used here as power handling device. By controlling the power balance, the same hardware can be used for acceleration and braking, providing the reduction of harmonics and robust response. A simulation of the complete system during braking mode has been performed both in Matlab and Simulink, and their results have been compared. The functionality of the proposed control has been shown and discussed, with full regeneration achieved. A round-trip efficiency (wheel to wheel higher than 80% has been obtained.
Improved Design Methods for Robust Single- and Three-Phase ac-dc-ac Power Converters
Qin, Zian
becomes a emerging challenge. Accordingly, installation of sustainable power generators like wind turbines and solar panels has experienced a large increase during the last decades. Meanwhile, power electronics converters, as interfaces in electrical system, are delivering approximately 80 % electricity...... aspects as: control methods, auxiliary circuits, and application criteria. The details are as follows: 1. new modulation schemes of single-phase B6 and H6 converters for improved performance, 2. an optimal active power decoupling approach for kW-scale single-phase converters to achieve high power density......After a century of fast developing, the society is facing energy issues again, e.g. the exhaustion of fossil fuel, emission caused air pollution, radiation leakage of nuclear generation, and so on. How to produce and use electricity in a more sustainable, efficient, and cost-effective way thus...
DC to DC power converters and methods of controlling the same
Steigerwald, Robert Louis; Elasser, Ahmed; Sabate, Juan Antonio; Todorovic, Maja Harfman; Agamy, Mohammed
2012-12-11
A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.
The application of standardized control and interface circuits to three dc to dc power converters.
Yu, Y.; Biess, J. J.; Schoenfeld, A. D.; Lalli, V. R.
1973-01-01
Standardized control and interface circuits were applied to the three most commonly used dc to dc converters: the buck-boost converter, the series-switching buck regulator, and the pulse-modulated parallel inverter. The two-loop ASDTIC regulation control concept was implemented by using a common analog control signal processor and a novel digital control signal processor. This resulted in control circuit standardization and superior static and dynamic performance of the three dc-to-dc converters. Power components stress control, through active peak current limiting and recovery of switching losses, was applied to enhance reliability and converter efficiency.
Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count
Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin;
2009-01-01
to switch with a three-level output voltage, where the middle neutral potential is uniquely tapped from the star-point of a wye-connected capacitive filter placed before the front-end diode rectifier for input current filtering. Through careful control, the resulting converter can produce the correct volt......-second average at its output, while simultaneously achieving inductive voltage boosting by shooting through either an appropriately selected inverter phase-leg or two phase-legs being commanded simultaneously. More interestingly, these performance features are achieved with no increase in the number...
Chen, Juan
2008-01-01
This report is the result of a Master Thesis work done at Seaward Electronics Inc. in Beijing, China from June to December in 2007. The main goal for this thesis is to verify and improve the performance of Honey-PWM DC-DC converter, which has been fabricated by a standard 0.6um CMOS processes. The project was started with studying of Buck converter structure. After the understanding of the converter structure, the project goes in to the analyses phase for each sub-cells, including the theory,...
Voltage Regulator for a dc-to-dc Converter
Mclyman, C. W.
1983-01-01
New voltage regulator isolates signals from power-switching converter without use of complex circuitry or optical couplers. Only addition is extra secondary winding on existing interstage transformer. Error signals shortcircuit new winding and inhibit converter action. Resistor in series with primary winding limits short-circuit current to prevent damage to circuit components. Extra transformer winding eliminates need for isolation components.
CIECA - Application to current programmed switching Dc-Dc converters
Chetty, P. R. K.
1982-09-01
The current injection equivalent circuit approach (CIECA) to modeling switching converter power stages is extended to model the current programmed converter power stages operating in fixed frequency, continuous inductor conduction mode. To demonstrate the method, modeling is carried out for the buck, boost, and buckboost converters to obtain small-signal linear equivalent circuit models which represent both input and output properties. The results of these analyses are presented in the form of linear equivalent circuit models as well as transfer functions. Though current programmed converters exhibit single-pole response, the addition of artificial ramp changes converters to exhibit well damped two-pole response. This has been investigated for the first time using CIECA. The results of these analyses are presented in the form of linear equivalent circuit models as well as transfer functions.
Research of Three-Phase AC/DC Converter Based on Matrix Converter%矩阵式AC/DC变换器研究
许柏宏; 葛红娟; 张文彬; 李后春
2013-01-01
A new type three-phase AC/DC converter topology is achieved by transforming 3-phase to 3-phase matrix converter. The current-source space vector modulation strategy is adopted to analyze in detail. Expressions of output voltage under this modulation strategy are derived. By adding a resonant inductor and a blocking capacitor, it is possible to a-chieve soft commutation for most of the semiconductor elements, and the process of commutation is given in detail. Meanwhile, the control method is proposed to be built in dq synchronous rotating frame based on the grid voltage vector , which increases power factor of input by changing the modulation vector. Simulation results validate correctness and feasibility of the theory and control strategy proposed in this paper.%对三相/三相矩阵变换器进行变换,得到一种衍生的AC/DC变换器拓扑.采用电流型空间矢量调制策略,推导出在该调制策略下的输出电压的表达式.通过在拓扑中加入一个谐振电感和隔直电容,使得双向开关器件可以实现软开关换流,并详细分析了换流过程.将控制算法建立在以电源电压矢量定向的dq同步旋转坐标系中,改变调制矢量实现功率因数调节.仿真结果验证了理论和控制方案的正确性和可行性.
GAO Chao
2008-01-01
A new family of converters, high-performance AC/DC power factor correction (PFC) switching converters with one-cycle control technology and active floating-charge technology, was derived and experimentally verified. The topology of a single-phase CCM and DCM Boost-PFC switching converter was also analyzed. Its operating prniciples and control methods were expounded. Based on these, a new type of AC/DC switching converter circuits for PFC combined with one-cycle control technology was presented herein. The proposed AC/DC switching converter significantly helps improve the converter efficiency and its power factor value.
Hybrid-Circuit Module For Dc-To-Dc Power Converter
Vorperian, Vatche; Detwiler, Robert; Karmon, Dan
1996-01-01
Power hybrid module is general-purpose power-switching module providing flexibility in design and application. Complete dc-to-dc power converter constructed by adding input/output filters and feedback circuitry to module to suit specific application.
Luo, Fang Lin
2003-01-01
INTRODUCTIONHistorical ReviewMultiple Quadrant ChoppersPump CircuitsDevelopment of DC/DC Conversion TechniqueCategorize Prototypes and DC/DC Converters Family TreeVOLTAGE-LIFT CONVERTERSIntroductionSeven Self-Lift ConvertersPositive Output Luo-ConvertersNegative Output Luo-ConvertersModified Positive Output Luo-Converters Double Output Luo-ConvertersPOSITIVE OUTPUT SUPER-LIFT LUO-CONVERTERS IntroductionMain SeriesAdditional SeriesEnhanced Series Re-Enhanced Series Multiple-Enhanced Series Summary of Positive Output
Mohammed, K. G.; Ramli, A. Q.; Amirulddin, U. A. U.
2013-06-01
This paper proposes the design of a new bi-directional DC-AC rotary converter machine to convert a d.c. voltage to three-phase voltage and vice-versa using a two-stage energy conversion machine. The rotary converter consists of two main stages which are combined into single frame. These two stages are constructed from three main electromagnetic components. The first inner electromagnetic component represents the input stage that enables the DC power generated by solar energy from photo-voltaic cells to be transformed by the second and third components electro-magnetically to produce multi-phase voltages at the output stage. At the same time, extra kinetic energy from wind, which is sufficiently available, can be added to existing torque on the second electromagnetic component. Both of these input energies will add up to the final energy generated at the output terminals. Therefore, the machine will be able to convert solar and wind energies to the output terminals simultaneously. If the solar energy is low, the available wind energy will be able to provide energy to the output terminals and at the same time charges the batteries which are connected as backup system. At this moment, the machine behaves as wind turbine. The energy output from the machine benefits from two energy sources which are solar and wind. At night when the solar energy is not available and also the load is low, the wind energy is able to charge the batteries and at the same time provides output electrical power to the remaining the load. Therefore, the proposed system will have high usage of available renewable energy as compared to separated wind or solar systems. MATLAB codes are used to calculate the required dimensions, the magnetic and electrical circuits parameters to design of the new bi-directional rotary converter machine.
Llopis, Francisco
2013-01-01
The circuit presented in this paper aims at providing three 40 Vpp 50Hz AC voltages sources with 120-degree phase separation between them. This is a fully analogue circuit that uses standard, low-cost electronic components without resorting to a microcontroller as previously proposed by Shirvasar et al [1]. This circuit may serve as a basis for a low-voltage 3P-AC power supply that students may safely use to realize experiments, i.e. about the principles and applications of three-phase AC power lines, without the risk of electric shocks.
A Non-linear Controller for Single-Phase AC-AC Power Converter to meet UPS Performance Index
Abdelhafid Ait Elmahjoub
2012-07-01
Full Text Available This article focuses on AC-AC power converter that can be used for uninterruptible power supply (UPS. The converter is built on two stages: a AC-DC input stage and a DC-AC output stage. The two blocks are connected by an intermediate DC bus. The aim of control is threefold: i power factor correction ii regulation of DC bus iii generating a sinusoidal voltage at the output. The synthesis of controllers has been achieved through the technique of nonlinear backstepping control. A detailed analysis of the stability control system is presented. The performances of regulators have been validated by numerical simulation in MATLAB / SIMULINK.
Single stage single phase active power factor corrected Ĉuk Topology Based AC-DC Converter
Md. Ismail Hossain
2014-03-01
Full Text Available This paper focuses on the analysis of a power factor correction (PFC converter using close loop Ĉuk 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 Ĉuk 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 Ĉuk rectifier and close loop Ĉuk rectifier is presented. An algorithm for implementing close loop Ĉuk rectifier in digital domain is developed and simulated.
Controlling DC-DC converters by chaos-based pulse width modulation to reduce EMI
Li Hong [Department of Mathematics and Computer Science, FernUniversitaet in Hagen, 58084 Hagen (Germany)], E-mail: hong.li@FernUni-Hagen.de; Zhang Bo [School of Electric Power, South China University of Technology, Guangzhou (China); Li Zhong; Halang, Wolfgang A. [Department of Mathematics and Computer Science, FernUniversitaet in Hagen, 58084 Hagen (Germany); Chen Guanrong [Department of Electronic Engineering, City University of Hong Kong, Hong Kong (China)
2009-11-15
In this paper, periodic and chaotic behaviors of DC-DC converters under certain parametric conditions are simulated, experimentally verified, and analyzed. Motivated by the work of J.H.B. Deane and D.C. Hamill in 1996, where chaotic phenomena are useful in suppressing electromagnetic interference (EMI) by adjusting the parameters of the DC-DC converter and making it operate in chaos, a chaos-based pulse width modulation (CPWM) is proposed to distribute the harmonics of the DC-DC converters continuously and evenly over a wide frequency range, thereby reducing the EMI. The output waves and spectral properties of the EMI are simulated and analyzed as the carrier frequency or amplitude changes with regard to different chaotic maps. Simulation and experimental results are given to illustrate the effectiveness of the proposed CPWM, which provides a good example of applying chaos theory in engineering practice.
Low noise DC to DC converters for the sLHC experiments
Allongue, B; Blanchot, G; Faccio, F; Fuentes, C; Michelis, S; Orlandi, S, E-mail: georges.blanchot@cern.c [CERN, Route de Meyrin, CH-1211 Geneva 23 (Switzerland)
2010-11-15
The development of front-end systems for the ATLAS tracker at the sLHC is now in progress and the availability of radiation tolerant buck converter ASICs enables the implementation of DC to DC converter based powering schemes. The front-end systems powered in this manner will be exposed to the radiated and conducted noise emitted by the converters. The electromagnetic compatibility between DC to DC converters and ATLAS short strip tracker hybrid prototypes has been studied with specific susceptibility tests. Different DC to DC converter prototypes have been designed following a noise optimization methodology to match the noise requirements of these front-end systems. The DC to DC converter developed in this manner presents a negligible emission of noise that was confirmed by system tests on an ATLAS tracker front-end module prototype. As a result of this, power converters can now be integrated in close vicinity of front-end chips without compromising their overall noise performance.
A continuous nonlinear model approach to study the behavior of large signal DC to DC converters
Guinjoan, Francisco
The study of signal switching DC-DC converters behavior is addressed. Given the fact that the linear methods cannot be used in this case, a nonlinear model was developed. The power stage nonlinear continuous model, which can be applied in both conduction modes (continuous and discontinuous), is obtained from the partition of the characteristic state vector variables in two subsets. This method is applied to the elementary switching cells (buck, boost, and buck-boost) and Cuk converter. It is oriented to the fast numerical simulation by means of general purpose simulation programs. Different results from numerical simulations, confirming the accuracy of the method used, either in an open loop or in a closed loop, are obtained, provided the validity of its domain is respected. The nonlinear model linearization made it possible to obtain equivalent transmittances for the DC-DC converters. Its application to a boost converter operating in the discontinuous condition mode at variable frequency rate enables the comparison of the obtained results with other existing methods and equivalence between the two of them to be easily established. The revision of the initial hypothesis leads to the establishment of a small signal model valid in the high frequency domain and to the results obtained being derived in a more systematic way. A model for switching DC-DC converters is given. Its validity is established, whatever its order and conduction modes, either in an open loop or a closed loop.
Radiation effects on DC-DC Converters
Zhang, Dexin; Attia, John O.; Kankam, Mark D. (Technical Monitor)
2000-01-01
DC-DC switching converters are circuits that can be used to convert a DC voltage of one value to another by switching action. They are increasing being used in space systems. Most of the popular DC-DC switching converters utilize power MOSFETs. However power MOSFETs, when subjected to radiation, are susceptible to degradation of device characteristics or catastrophic failure. This work focuses on the effects of total ionizing dose on converter performance. Four fundamental switching converters (buck converter, buck-boost converter, cuk converter, and flyback converter) were built using Harris IRF250 power MOSFETs. These converters were designed for converting an input of 60 volts to an output of about 12 volts with a switching frequency of 100 kHz. The four converters were irradiated with a Co-60 gamma source at dose rate of 217 rad/min. The performances of the four converters were examined during the exposure to the radiation. The experimental results show that the output voltage of the converters increases as total dose increases. However, the increases of the output voltage were different for the four different converters, with the buck converter and cuk converter the highest and the flyback converter the lowest. We observed significant increases in output voltage for cuk converter at a total dose of 24 krad (si).
High-Efficiency dc/dc Converter
Sturman, J.
1982-01-01
High-efficiency dc/dc converter has been developed that provides commonly used voltages of plus or minus 12 Volts from an unregulated dc source of from 14 to 40 Volts. Unique features of converter are its high efficiency at low power level and ability to provide output either larger or smaller than input voltage.
Efficient Wide Range Converters (EWiRaC): A new family of high efficient AC-DC Converters
Petersen, Lars; Andersen, Michael Andreas E.
2006-01-01
The performance in terms of efficiency of the existing power supplies used for PFC is very dependent on the input voltage range. The boost converter is the most commonly used PFC converter because of its simplicity and high efficiency. But, the boost converter as well as other known converters...... the converter topology according to the input voltage. This new converter type has been named: efficient wide range converter (EWiRaC). The performance of the EWiRaC is experimental verified in a universal input range (90-270VAC) application with an output voltage of 185VDC capable of 500W output power. The EWi...
Efficiency Enhancement of DC to DC Multilevel Boost Converter and Its Applications
R. Ravikumar
2015-03-01
Full Text Available The aim of this study is to propose a experimental verification for single-phase to three phase drive system composed of two parallel single-phase rectifiers, a three-phase inverter and an induction motor. Apart from traditional application in dc motor drives, new applications of BDC include energy storage in renewable energy systems, fuel cell energy systems, Hybrid Electric Vehicles (HEV and Uninterruptible Power Supplies (UPS. A dc-dc converter is always required to allow energy exchange between storage device and the rest of system. In HEV applications, BDCs are required to link different dc voltage buses and transfer energy between them. A non-isolated bi-directional dc-dc converters is used in our project to achieve better efficiency.
Local Bifurcations in DC-DC Converters
2012-01-01
Three local bifurcations in DC-DC converters are reviewed. They are period-doubling bifurcation, saddle-node bifurcation, and Neimark bifurcation. A general sampled-data model is employed to study the types of loss of stability of the nominal (periodic) solution and their connection with local bifurcations. More accurate prediction of instability and bifurcation than using the averaging approach is obtained. Examples of bifurcations associated with instabilities in DC-DC converters are given.
DC/DC Converter Stability Testing Study
Wang, Bright L.
2008-01-01
This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop oscillation. In particular, certain channel power levels of converter input noises have been found to have high degree correlation with the gain/phase margins. It becomes a potential new method to evaluate stability levels of all type of DC/DC converters by utilizing the spectral analysis on converter input noises.
The Design of a Single-Phase AC-DC Converter Circuit%单相 AC-DC 变换电路设计
张凤运; 段书凯; 王丽丹; 钟宇平; 李波
2015-01-01
Taking into consideration the fact that it is difficult to further improve the power conversion effi‐ciency with the current AC‐DC switching power supply based on the transformer ,a new type of AC‐DC conversion circuit is designed in the present study .A single‐phase AC‐DC conversion circuit designed by us combines the power factor measurement with compensation circuit and realizes highly efficient AC ‐DC con‐version through the MCU (Microcontroller Unit)control system .The ideal diode bridge controller LT 4320 and the efficient switching regulator controller LTC 3789 realize the conversion of 36V AC input to 24 DC output .Through the Atmega128 MCU control system combined with the measurement circuit of power factor which is based on the comparator LM393 ,the measurement and compensation of the power factor are accomplished .In addition ,by using the N M OSFET with 15 m Ω's resistance as the power device ,the efficiency of the switching power supply is improved .This design has advantages over the traditional trans‐former‐based AC‐DC conversion circuit by its high conversion efficiency ,strong applicability and good de‐sign plan .%针对当前基于变压器的 ACDC 开关电源很难进一步提高电源转换效率的问题，设计了一个新型的变换电路。本次设计的单相 AC‐DC 变换电路结合了功率因素测量和补偿电路，通过单片机控制系统实现 AC‐DC 的高效转换。理想二极管桥控制器 LT4320与高效开关稳压控制器 LTC3789实现24 V 的交流输入到36 V 的直流输出，通过 Atmega128单片机控制系统结合基于比较器 LM393的功率因素测量电路，完成电源功率因数的测量与补偿；另外，以导通电阻为15 m Ω的 N 型 MOSFET 作为功率器件，最大限度地提高了电源的转换效率。本设计方案优于传统的基于变压器的 AC‐DC 变换，具有转换效率高、应用性强和设计方案完善等特点。
A resonant dc-dc power converter assembly
2015-01-01
The present invention relates to a resonant DC-DC power converter assembly comprising a first resonant DC-DC power converter and a second resonant DC-DC power converter having identical circuit topologies. A first inductor of the first resonant DC-DC power converter and a second inductor...... of the second resonant DC-DC power converter are configured for magnetically coupling the first and second resonant DC-DC power converters to each other to forcing substantially 180 degrees phase shift, or forcing substantially 0 degree phase shift, between corresponding resonant voltage waveforms of the first...... and second resonant DC-DC power converters. The first and second inductors are corresponding components of the first and second resonant DC-DC power converters....
Rf-to-dc power converters for wireless powering
Ouda, Mahmoud Hamdy
2016-12-01
Various examples are provided related to radio frequency (RF) to direct current (DC) power conversion. In one example, a RF-to-DC converter includes a fully cross-coupled rectification circuit including a pair of forward rectifying transistors and a feedback circuit configured to provide feedback bias signals to gates of the pair of forward rectifying transistors via feedback branch elements. In another example, a method includes receiving a radio frequency (RF) signal; rectifying the RF signal via a fully cross-coupled rectification circuit including a pair of forward rectifying transistors; and providing a DC output voltage from an output connection of the fully cross-coupled rectification circuit, where gating of the pair of forward rectifying transistors is controlled by feedback bias signals provided to gates of the pair of forward rectifying transistors via feedback branch elements.
Pulse-width modulated DC-DC power converters
Kazimierczuk, Marian K
2008-01-01
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,
CMOS-Compatible SOI MESFETS for Radiation-Hardened DC-to-DC Converters
Thornton, Trevor; Lepkowski, William; Wilk, Seth
2013-01-01
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.
Mi, Chris; Li, Siqi
2017-01-31
A bidirectional AC-DC converter is presented with reduced passive component size and common mode electro-magnetic interference. The converter includes an improved input stage formed by two coupled differential inductors, two coupled common and differential inductors, one differential capacitor and two common mode capacitors. With this input structure, the volume, weight and cost of the input stage can be reduced greatly. Additionally, the input current ripple and common mode electro-magnetic interference can be greatly attenuated, so lower switching frequency can be adopted to achieve higher efficiency.
Design of coolant distribution system (CDS) for ITER PF AC/DC converter
Guo, Bin [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Song, Zhiquan, E-mail: zhquansong@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Fu, Peng; Xu, Xuesong; Li, Chuan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wang, Min; Dong, Lin [China International Nuclear Fusion Energy Program Execution Center, Beijing 100862 (China)
2016-10-15
Highlights: • System process and arrangement has been proposed to meet the multiple requirements from the converter system. • Thermal hydraulic analysis model has been developed to size and predict the system operation behavior. • Prototype test has been performed to validate the proposed design methodology. - Abstract: The Poloidal Field (PF) converter unit, playing an essential role in the plasma shape and position control in vertical and horizontal direction, which is an important part of ITER power supply system. As an important subsystem of the converter unit, the coolant distribution system has the function to distribute the cooling water from ITER component cooling water system (CCWS) to its main components at the required flow rate, pressure and temperature. This paper presents the thermal hydraulic design of coolant distribution system for the ITER PF converter unit. Different operational requirements of the PF converter unit regarding flow rate, temperature and pressure have been analyzed to design the system process and arrangement. A thermal-hydraulic analysis model has been built to size the system and predict the flow rate and temperature distribution of the system under the normal operation. Based on the system thermal-hydraulic analysis results, the system pressure profile has been plotted to evaluate the pressure behavior along each client flow path. A CDS prototype for the ITER PF converter has been constructed and some experiments have been performed on it. A good agreement of the flow distribution and temperature behavior between the simulated and test results validate the proposed design methodology.
Multiport Resonant DC-DC Converter
Tran, Yan-Kim; Dujic, Drazen; Barrade, Philippe
2015-01-01
his paper presents a multiport galvanically isolated LLC resonant DC-DC converter suitable for DC applications. A three-port structure is analyzed, with full bidirectional power flow capabilities, simple control and behavior similar to that expected from a DC transformer. Each port is equipped with half-bridge modules accompanied with tuned resonant tank, partly realized with elements of a multi- winding high frequency transformer. With some restrictions that are explained in the paper, each ...
Security analysis of interconnected AC/DC systems
Eriksson, Robert
2015-01-01
This paper analyses N-1 security in an interconnected ac/dc transmission system using power transfer distribution factors (PTDFs). In the case of a dc converter outage the power needs to be redistributed among the remaining converter to maintain power balance and operation of the dc grid. The red......This paper analyses N-1 security in an interconnected ac/dc transmission system using power transfer distribution factors (PTDFs). In the case of a dc converter outage the power needs to be redistributed among the remaining converter to maintain power balance and operation of the dc grid....... The redistribution of power has a sudden effect on the power-flow in the interconnected ac system. This may cause overloading of lines and transformers resulting in disconnection of equipment, and as a consequence cascading failure. The PTDF is used as a method to analyze and avoid violating limits by in the dc...
CMOS Integrated Capacitive DC-DC Converters
Van Breussegem, Tom
2013-01-01
This book provides a detailed analysis of all aspects of capacitive DC-DC converter design: topology selection, control loop design and noise mitigation. Readers will benefit from the authors’ systematic overview that starts from the ground up, in-depth circuit analysis and a thorough review of recently proposed techniques and design methodologies. Not only design techniques are discussed, but also implementation in CMOS is shown, by pinpointing the technological opportunities of CMOS and demonstrating the implementation based on four state-of-the-art prototypes. Provides a detailed analysis of all aspects of capacitive DC-DC converter design; Analyzes the potential of this type of DC-DC converter and introduces a number of techniques to unleash their full potential; Combines system theory with practical implementation techniques; Includes unique analysis of CMOS technology for this application; Provides in-depth analysis of four fabricated prototypes.
Design of a New AC–DC Single-Stage Full-Bridge PWM Converter with Two Controllers
R. Ramesh,
2014-03-01
Full Text Available Single phase power factor correction ac-dc converters are widely used in industry for ac-dc power conversion from single phase ac mains to an required output dc voltage. In case of high power application these types of converter use an ac-dc boost converter followed by dc-dc converter. These converters has the features of excellent input power factor, continuous input and output currents, and intermediate dc bus voltage and reduce the number of semiconductor devices for such cost-effective applications.
Power-Based Control for a Bidirectional AC-DC Power Converter
del Puerto Flores, Dunstano; Scherpen, Jacquelien M.A.
2011-01-01
In many electrical applications it is indispensable that the power converter can operate as a generating or rectifier unit, and the controller must be able to handle this bidirectional power flow. An application example is the doubly fed induction machine, where power can flow in both directions thr
Minimizing the total harmonic distortion for a 3 kW, 20 kHz ac to dc converter using SPICE
Lollar, Louis F.; Kapustka, Robert E.
1988-01-01
This paper describes the SPICE model of a transformer-rectified-filter (TRF) circuit and the Micro-CAP (Microcomputer Circuit Analysis Program) model and their application. The models were used to develop an actual circuit with reduced input current THD. The SPICE analysis consistently predicted the THD improvements in actual circuits as various designs were attempted. In an effort to predict and verify load regulation, the incorporation of saturable inductor models significantly improved the fidelity of the TRF circuit output voltage.
Jordi Everts
2016-10-01
Full Text Available The growing attention on plug-in electric vehicles, and the associated high-performance demands, have initiated a development trend towards highly efﬁcient and compact on-board battery chargers. These isolated ac-dc converters are most commonly realized using two conversion stages, combining a non-isolated power factor correction (PFC rectiﬁer with an isolated dc-dc converter.This, however, involves two loss stages and a relatively high component count, limiting the achievable efﬁciency and power density and resulting in high costs. In this paper, a single-stage converter approach is analyzed to realize a single-phase ac-dc converter, combining all functionalities into one conversion stage and thus enabling a cost-effective efﬁciency and power density increase. The converter topology consists of a quasi-lossless synchronous rectiﬁer followed by an isolated dual active bridge (DAB dc-dc converter, putting a small ﬁlter capacitor in between. To show the performance potential of this bidirectional, isolated ac-dc converter, a comprehensive design procedure and multi-objective optimization with respect to efﬁciency and power density is presented, using detailed loss and volume models. The models and procedures are veriﬁed by a 3.7kW hardware demonstrator, interfacing a 400Vdc-bus with the single-phase 230V,50Hz utility grid. Measurement results indicate a state-of-the-art efﬁciency of 96.1% and power density of 2 kW/dm3, conﬁrming the competitiveness of the investigated single-stage DAB ac-dc converter.
SINGLE PHASE HIGH FREQUENCY AC CONVERTER FOR INDUCTION HEATING APPLICATION
M.A INAYATHULLAAH,
2010-12-01
Full Text Available The proposed topology reduces the total harmonic distortion (THD of a high frequency AC/AC Converter well below the acceptable limit. This paper deals with a novel single phase AC/DC/AC soft switching utility frequency AC to high frequency AC converter. In this paper a single phase full bridge inverter with Vienna rectifier as front end is used instead of conventional diode bridge rectifier to provide continuous sinusoidal input current with nearly unity power factor at the source side with extremely low distortion.. This power converter is more suitable and acceptable for cost effective high frequency (HF consumer induction heating applications.
Parametric study of minimum converter loss in an energy-storage dc-to-dc converter
Wong, R. C.; Owen, H. A., Jr.; Wilson, T. G.
1982-01-01
Through a combination of analytical and numerical minimization procedures, a converter design that results in the minimum total converter loss (including core loss, winding loss, capacitor and energy-storage-reactor loss, and various losses in the semiconductor switches) is obtained. Because the initial phase involves analytical minimization, the computation time required by the subsequent phase of numerical minimization is considerably reduced in this combination approach. The effects of various loss parameters on the optimum values of the design variables are also examined.
顾玲; 金科; 周慧龙
2015-01-01
为了同时实现升降压AC/DC变换和高功率因数控制，提出一种单级式隔离型三相双向AC/DC变换器及其改进型空间矢量脉宽调制(space vector pulse width modulation，SVPWM)策略。该拓扑具有功率因数高、升降压输出、高频电气隔离以及电能双向流动的优点，适合作为380 V直流微网与电网之间的接口变换器。它与传统的三相电压型脉宽调制整流器相比，不需要外加工频变压器或者DC/DC降压变换环节，具有功率密度更高、成本更低的优点。给出变换器的推导过程以及工作原理，提出基于该拓扑的 SVPWM 调制策略，并分析变换器的直通问题。最后，在实验室研制一台由DSP TMS320F2812控制的3kW原理样机，实验结果验证了所提出的拓扑及其SVPWM算法的可行性。%To achieve buck-boost AC/DC conversion and high power factor as well, this paper proposes a single-stage three-phase isolated bidirectional AC/DC converter based on the modified space vector pulse width modulation (SVPWM) algorithm. The converter can achieve high power factor, buck-boost output voltage, high-frequency electrical isolation and bidirectional energy flow with single-stage structure. It is suitable as the grid-connected converter of 380V DC microgrid. Compared with the three-phase voltage-type PWM rectifier, the proposed converter has larger power density and lower cost, as it doesn’t need extra industrial frequency transformer or DC/DC buck converter. The converter’s derivation and operation principles are presented, and its SVPWM algorithm is proposed. The shoot-through problem of the converter is analyzed as well. A 3kW hardware based on the proposed converter was built in the lab with the digital controller TMS320F2812. And the experimental results verified the theoretical analysis well.
Modified Multiport Dc-Dc Converter Topology For Smart Grid
Dhamodharan Shanmugam
2013-10-01
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.
A High Power Factor Single-phase AC-DC Converter%一种高功率因数的单相AC-DC变换器
李雨; 丁志勇; 李鹏鹏
2014-01-01
设计了一种有源功率因数校正（APFC）的高功率因数单相AC-DC变换器。该系统以TI公司专用APFC控制芯片UCC28019为控制核心，实现BOOST式APFC，后级以高效控制芯片TPS54360为控制器，输出恒压36 V，最大输出电流为2.5 A。该系统采用STC12C5A60S2单片机为监测控制中心，具有输出过流保护和功率因数、输出电压、输出电流实时测量和显示功能。在设计时，该系统从布局布线和滤波等方面消除了电磁干扰，使电压调整率和负载调整率都在0.5%以下，工作性能稳定、可靠。%An active Power Factor Correction(APFC)high power factor single-phase AC-DC converter. The system is dedicated to TI’s UCC28019 APFC control chip to control the core, to achieve BOOST type APFC, after the class in an efficient control chip TPS54360 controller, constant voltage output 36 V, maximum output current of 2.5 A. The system uses STC12C5A60S2 microcontroller monitoring control center, with output overcurrent protection and power factor, output voltage, output current, real-time measurement and display functions. In the design, the system layout and filtering from the elimination of electromagnetic interference, voltage regulation and load regulation are 0.5%, stable performance, reliable.
Radiation Effects on DC-DC Converters
Zhang, De-Xin; AbdulMazid, M. D.; Attia, John O.; Kankam, Mark D. (Technical Monitor)
2001-01-01
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
Design of Energy Storage Reactors for Dc-To-Dc Converters. Ph.D. Thesis
Chen, D. Y.
1975-01-01
Two methodical approaches to the design of energy-storage reactors for a group of widely used dc-to-dc converters are presented. One of these approaches is based on a steady-state time-domain analysis of piecewise-linearized circuit models of the converters, while the other approach is based on an analysis of the same circuit models, but from an energy point of view. The design procedure developed from the first approach includes a search through a stored data file of magnetic core characteristics and results in a list of usable reactor designs which meet a particular converter's requirements. Because of the complexity of this procedure, a digital computer usually is used to implement the design algorithm. The second approach, based on a study of the storage and transfer of energy in the magnetic reactors, leads to a straightforward design procedure which can be implemented with hand calculations. An equation to determine the lower-bound volume of workable cores for given converter design specifications is derived. Using this computer lower-bound volume, a comparative evaluation of various converter configurations is presented.
应用于V2G的AC/DC矩阵变换器%AC/DC Matrix Converters for V2G Applications
王辉; 粟梅; 孙尧; 李幸; 韩华; 张关关
2013-01-01
Due to the problems of battery voltage adaptation and power-volume ratio and system efficiency of the pulse width modulation (PWM) voltage source rectifier (VSR)in vehicle to grid (V2G) systems,this paper presents a solution based on AC/DC matrix converter topology for the V2G Against the characteristic of relatively large charging current ripple in the classical current space vector modulation strategy,a sectional optimized modulation strategy that can reduce the charging current ripple within the whole output range was proposed.The comparative analysis was made between the classical current space vector modulation strategy and the proposed strategy.The simulation and experimental results demonstrate the validity and effectiveness of the proposed sectional optimized modulation strategy.%由于当前V2G系统中普遍采用的电压型脉宽调制(pulse width modulation,PWM)整流方案中所存在的蓄电池电压匹配、功率体积比及系统效率问题,提出一种采用AC/DC矩阵变换器的解决方案.针对经典电流空间矢量调制策略中充电电流纹波较大的缺点,提出一种在全输出范围内减小充电电流纹波的分段优化调制策略,并深入对比分析这两种调制策略下充电电流纹波的大小.仿真和实验结果表明,所提分段优化调制策略的正确性和可行性.
Mohd Tariq
2014-12-01
Full Text Available The paper presents the modeling, simulation and digital implementation of power quality improvement of DC drives by using multi pulse AC–DC converter. As it is a well-known fact that power quality determines the fitness of electrical power to consumer devices, hence an effort has been made to improve power quality in this work. Simulation and digital implementation with the help of MATLAB/Simulink has been done and results obtained are discussed in detail to verify the theoretical results. The multipulse converter was connected with DC drives and was run at no load condition to find out the transient and steady state performances. FFT analysis has been performed and Total Harmonic Distortion (THD results obtained at different pulses are shown here.
Radiation-Tolerant DC-DC Converters
Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn
2012-01-01
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).
Improvement on control strategy for matrix AC/DC converter%一种矩阵式AC/DC变换器控制策略改进
吴胜华; 郑勃; 刘潇
2014-01-01
为进一步改善之前提出的矩阵式AC/DC变换器性能，依据三相/一相矩阵式变换器(3/1MC)与其等效拓扑开关函数之间的瞬时对应关系以及限定条件，研究了一种改进的控制策略．该策略充分利用X扇区中三相电压资源，合理分配各相电压的作用时间(占空比)及各双向开关的门极驱动信号．使双向开关的有效导通角为180°，各相输入电流SPWM脉冲序列均匀、等间隔地分布在时间轴上，且分别跟随输入电压．仿真结果表明，网侧谐波电流小，功率因数接近1．%To improve further the performances on the matrix AC/DC converter previously proposed, this paper investigates an improved control strategy, in terms of the instantaneous corresponding relationship between the three phase/single phase matrix converter (3/1MC) and its equivalent topology switch function as well as the limiting conditions. By the control strategy, three-phase voltage resource is utilized fully in X sector, and the active time (duty factor) of each phase voltages and the gate driving signals of each bidirectional switches are allocated reasonably. Therefore, the effective conductive angle of bidirectional switches is made to be 180° , the SPWM pulse sequences of each phase input current are distributed on time axis with equal interval and uniformity, and are allowed to follow the input voltages respectively. Simulation results show that the harmonic current at grid side is lower, and the power factor is approaching to be 1.
DC to DC Converter Testing for Space Applications: Use of EMI Filters and Thermal Range of Operation
Leon, Rosa
2008-01-01
Several tests were performed on Interpoint and International Rectifier (IR) direct current (DC) to DC converters to evaluate potential performance and reliability issues in space use of DC to DC converters and to determine if the use of electromagnetic interference (EMI) filters mitigates concerns observed during previous tests. Test findings reported here include those done up until September - October 2008. Tests performed include efficiency, regulation, cross-regulation, power consumption with inhibit on, load transient response, synchronization, and turn-on tests. Some of the test results presented here span the thermal range -55 C to 125 C. Lower range was extended to -120 C in some tested converters. Determination of failure root cause in DC/DC converters that failed at thermal extremes is also included.
Switching Arithmetic for DC to DC Converters Using Delta Sigma Modulator Based Control Circuit
K.Diwakar
2016-02-01
Full Text Available In the proposed arithmetic unit for dc to dc converters using delta sigma modulator, a new technique is proposed for addition and multiplication of sampled analog signals. The output is in digital form to drive the converters. The conventional method has input signal limitation whereas in the proposed method the inputs can vary to full-scale. The addition of two discrete signals is done by sampling the two signals at a period called update period and feeding each signal to the input of signal dependant delta sigma modulator for half of the update period and combining the outputs for the update period. The extension of three discrete data addition can be carried out by using the same technique. For the multiplication of two discrete signals different method is adopted. One analog signal is fed to the input of first delta-sigma modulator (DSM1 after sampling. The sampled output of the second analog signal is negated or not negated depending on the bit state at the output of DSM1 and is fed to the input of second DSM(DSM2. The resulting bit stream at the output of DSM2 is the digital representation of the product of the sampled data of the two analog signals. In order to multiply three discrete data, the sampled output of third data is negated or not negated depending on the bit state at the output of DSM2 and is fed to the input of third DSM(DSM3. The resulting bit stream at the output of DSM3 is the digital representation of the product of the sampled data of the three analog signals. Using the proposed adder and multiplier circuits any expressions can be evaluated such that the average value of the digital output of the arithmetic unit over the update period gives the value of expressions during that period. The digital output of the arithmetic unit is used to drive the dc-dc converters.
Liu, Jianxing; Laghrouche, Salah; Wack, Maxime
2014-06-01
In this paper, a full-bridge boost power converter topology is studied for power factor control, using output higher order sliding mode control. The AC/DC converters are used for charging the battery and super-capacitor in hybrid electric vehicles from the utility. The proposed control forces the input currents to track the desired values, which can control the output voltage while keeping the power factor close to one. Super-twisting sliding mode observer is employed to estimate the input currents and load resistance only from the measurement of output voltage. Lyapunov analysis shows the asymptotic convergence of the closed-loop system to zero. Multi-rate simulation illustrates the effectiveness and robustness of the proposed controller in the presence of measurement noise.
M. Annamalai
2012-01-01
Full Text Available The aim of this study is to simulate and implement open loop and closed loop controlled DC-DC converter for stand-alone wind energy system. Wind turbines, however, are not always very efficient in the wind speeds that are most common to a region. Typically, wind energy systems are designed to be highly efficient in high wind speed and have a cut-off wind speed- below which no energy is captured. In remote locations where wind energy is used for battery charging, the energy lost below the cut-off wind speed could be used for trickle charging or maintaining a batteryâs fully charged state. Wind turbines are most efficient when they are operated at one specific Tip-Speed to Wind-Speed Ratio (TSR. Therefore, for the efficient capture of wind power, turbine speed should be controlled to follow the ideal TSR, with an optimal operating point, which is different for every wind speed In this system, the DC-DC converter in the DC link with a constant dc voltage to the load, a DC-DC converter will allow the voltage at the output of a diode bridge rectifier to be controlled. In low wind speed conditions, the voltage may be lowered to prevent the dc link from reverse biasing the diode rectifier. Under high wind speed condition, the voltage may be increased, reducing I2R losses. In addition, adjusting the voltage on the dc rectifier will change the generator terminal voltage and thereby provide control over the current flowing out of the generator. The LCL-T resonant inverter system for both open loop and closed loop DC-to-DC converter systems are simulated using MATLAB simulink power system blocks. This converter has advantages like reduced transformer size, reduced filter size and current source characteristics. The simulation studies indicate that LCL-T type for open and closed loop DC-DC converter can be used with stand-alone wind generator. Constant voltage can be maintained at the output of DC-to-DC converter by using a PWM rectifier at the output
张犁; 吴田进; 冯兰兰; 孙凯; 邢岩
2012-01-01
研究模块化双向AC/DC变换器并联运行系统,分析指出现有单模块双向运行控制方法引起各并联模块的功率流向不一致的问题;研究系统功率流与直流母线电压变化趋势的内在联系,提出一种模块化AC/DC变换器的双向运行控制方法,分别采用正向和负向电压调节器以保证各并联模块的功率流向一致;整流和逆变状态以不同的直流母线电压运行、自然区分两种功率流向。提出的控制方法可以实现各并联模块整流与逆变之间的无缝切换。详细分析系统稳定性,并指出多模块并联对系统动态特性有所改善;给出关键参数的设计准则。搭建实验验证系统,进行稳态和动态实验。实验结果证明了所提出控制方法的可行性和有效性。%The issue of inconsistent power flow among modular bi-directional AC/DC converters in parallel operation with the conventional control was analyzed.The inherent relationship between system power flow and the trend of the DC bus voltage was researched and a bi-directional operation control for the modular AC/DC converter parallel system was proposed.The consistent power flow of each module is achieved by utilizing a positive and a negative DC bus voltage regulators.Power flows of rectification and inversion are distinguished naturally with different DC bus voltages,and seamless switching between rectification and inversion was also realized.The stability of the modular AC/DC converter parallel system was analyzed in detail with the design principle of the key parameter given.A prototype system was built and both of the steady-state and dynamic experimental results were presented to verify the effectiveness of the proposed system and control method.
High power density dc-to-dc converters for aerospace applications
Divan, Deepakraj M.
1990-01-01
Three dc-to-dc converter topologies aimed at high-power high-frequency applications are introduced. Major system parasitics, namely, the leakage inductance of the transformer and the device output capacitance are efficiently utilized. Of the three circuits, the single-phase and three-phase versions of the dual active bridge topology demonstrate minimal stresses, better utilization of the transformer, bidirectional, and buck-boost modes of operation. All circuits operate at a constant switching frequency, thus simplifying design of the reactive elements. The power transfer characteristics and soft-switching regions on the Vout-Iout plane are identified. Two coaxial transformers with different cross-sections were built for a rating of 50 kVA. Based on the single-phase dual active bridge topology, a 50 kW, 50 kHz converter operating at an input voltage of 200 Vdc and an output voltage of 1600 Vdc was fabricated. Characteristics of current-fed output make the dual active bridge topologies amenable to paralleling and hence extension to megawatt power levels. Projections to a 1 MW system operating from a 500 Vdc input, at an output voltage of 10 kVdc and a switching frequency of 50 kHz, using MOS-controlled thyristors, coaxially wound transformers operating at three times the present current density with cooling, and multilayer ceramic capacitors, suggests an overall power density of 0.075 to 0.08 kg/kW and an overall efficiency of 96 percent.
High power density dc-to-dc converters for aerospace applications
Divan, Deepakraj M.
1990-12-01
Three dc-to-dc converter topologies aimed at high-power high-frequency applications are introduced. Major system parasitics, namely, the leakage inductance of the transformer and the device output capacitance are efficiently utilized. Of the three circuits, the single-phase and three-phase versions of the dual active bridge topology demonstrate minimal stresses, better utilization of the transformer, bidirectional, and buck-boost modes of operation. All circuits operate at a constant switching frequency, thus simplifying design of the reactive elements. The power transfer characteristics and soft-switching regions on the Vout-Iout plane are identified. Two coaxial transformers with different cross-sections were built for a rating of 50 kVA. Based on the single-phase dual active bridge topology, a 50 kW, 50 kHz converter operating at an input voltage of 200 Vdc and an output voltage of 1600 Vdc was fabricated. Characteristics of current-fed output make the dual active bridge topologies amenable to paralleling and hence extension to megawatt power levels. Projections to a 1 MW system operating from a 500 Vdc input, at an output voltage of 10 kVdc and a switching frequency of 50 kHz, using MOS-controlled thyristors, coaxially wound transformers operating at three times the present current density with cooling, and multilayer ceramic capacitors, suggests an overall power density of 0.075 to 0.08 kg/kW and an overall efficiency of 96 percent.
Intelligent dc-dc Converter Technology Developed and Tested
Button, Robert M.
2001-01-01
The NASA Glenn Research Center and the Cleveland State University have developed a digitally controlled dc-dc converter to research the benefits of flexible, digital control on power electronics and systems. Initial research and testing has shown that conventional dc-dc converters can benefit from improved performance by using digital-signal processors and nonlinear control algorithms.
Regulated dc-to-dc converter for voltage step-up or step-down with input-output isolation
Feng, S. Y.; Wilson, T. G. (Inventor)
1973-01-01
A closed loop regulated dc-to-dc converter employing an unregulated two winding inductive energy storage converter is provided by using a magnetically coupled multivibrator acting as duty cycle generator to drive the converter. The multivibrator is comprised of two transistor switches and a saturable transformer. The output of the converter is compared with a reference in a comparator which transmits a binary zero until the output exceeds the reference. When the output exceeds the reference, the binary output of the comparator drives transistor switches to turn the multivibrator off. The multivibrator is unbalanced so that a predetermined transistor will always turn on first when the binary feedback signal becomes zero.
Gohil, Ghanshyamsinh Vijaysinh; Wang, Huai; Liserre, Marco
2014-01-01
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...
A new approach to improve dynamic characteristics of digitally controlled buck-boost dc-dc converter
2010-01-01
This paper presents a new digital control buck-boost dc-dc converter with bias model to improve dynamic characteristics. The buck-boost converter needs to respond appropriately to changing input voltage and load change with wide input voltage. This approach makes adjustment to the bias value by input voltage and output current. As a result, it is revealed that not only the dynamic characteristics but also static characteristics can be improved and it is effective for wide range input voltage.
A Feed-Forward Controlled AC-DC Boost Converter for Biomedical Implants
Jiang, Hao; Lan, Di; Lin, Dahsien;
2012-01-01
Miniaturization is important to make implants clinic friendly. Wireless power transfer is an essential technology to miniaturize implants by reducing their battery size or completely eliminating their batteries. Traditionally, a pair of inductively-coupled coils operating at radio-frequency (RF...... circuit for low turn-on voltage) [1]. In order to have a high induced voltage, the size of the receiving coil often is significantly larger than rest of the implant. A rotating magnets based wireless power transfer has been demonstrated to deliver the same amount of power at much lower frequency (around...... for powering biomedical implants....
ZVS Full-Bridge Based DC-DC Converter with Linear Voltage Gain According to Duty Cycle
Do, Hyun-Lark
2013-09-01
This paper presents a zero-voltage-switching (ZVS) full-bridge based DC-DC converter with linear voltage gain according to duty cycle. The proposed converter is based on an asymmetrical pulse-width-modulation (APWM) full-bridge converter which has various advantages over other converters. However, it has some drawbacks such as limited maximum duty cycle to 0.5 and narrow input range. The proposed converter overcomes these problems. The duty cycle is not limited and input voltage range is wide. Also, the ZVS operation of all power switches is achieved. Therefore, switching losses are significantly reduced and high-efficiency is obtained. Steady-state analysis and experimental results for the proposed converter are presented to validate the feasibility and the performance of the proposed converter.
单相有源AC-DC变换器的统一算法及其应用%Unified algorithm of single-phase active AC-DC converters and its applications
杨喜军; 凌志斌; 龚幼民; 叶芃生
2006-01-01
This paper discusses a novel boost single-phase active AC-DC converters, named low-end semi-controlled bridge AC-DC converter. By analysis, its topology and principle can be derived from the conventional single-phase power factor corrector (PFC). But it has also some differences, such as power device positions, inductor type, input voltage waveform detection and induction current detection, so its design is also different. The converter is implemented by employing two current detection approaches, i.e., current transformer detection and shunt resistor detection. Consequently, it can provide a steady DC output voltage with a low voltage ripple, approximately unitary input power factor and 2.5 kW output power. The experimental results show validity of the theoretical analysis.
Huffman, S.
1977-01-01
Detailed instructions on the use of two computer-aided-design programs for designing the energy storage inductor for single winding and two winding dc to dc converters are provided. Step by step procedures are given to illustrate the formatting of user input data. The procedures are illustrated by eight sample design problems which include the user input and the computer program output.
赵凯岐; 张殿华; 兰海; 岳文杰; 张强
2011-01-01
In design process of high-capacity AC-DC converter in ship electric propulsion system, the RC snubber circuit should be connected to the thyristor in parallel in order to absorb the energy generated at the moment of thyristor switching and suppress overvoltage impulses and high voltage change rate du/dt.However, parameter selection, which is generally depended on empirical formula, sometimes leads to a rather great error. Once the selection of protection parameters is unreasonable, a high spike voltage is likely to occur and render power electronic components will be easily damaged, which threatens the operation safety of equipments. In this paper, a new optimal design method of RC snubber circuit is proposed for thyristor in high-capacity AC-DC converter, R and C parameters and resistor power is deduced more accurately, and the reliability of the AC-DC converter is improved as a result. Numerical simulations and physical experiments are conducted to verify the feasibility and viability of the method.%船舶电力推进系统大功率AC-DC变换器设计时,必须在晶闸管的两端并联阻容缓冲器,以吸收器件关断过程反向恢复电流的能量,抑制高的过电压冲击及高的电压应力du/dt.但是,阻容参数的设计大多依靠经验公式,参数选取有时产生很大偏差,一旦选取不合理,便会产生很高的尖峰过电压,造成电力电子器件的损坏,影响系统安全运行.针对大功率AC-DC变换器晶闸管阻容缓冲器进行研究,提出了阻容缓冲器优化设计方法,推导出较精确的阻容参数值和电阻的功率,提高大功率AC-DC变换器的可靠性,仿真及实验验证了本方法的可行性.
Szczesniak, Pawel
2013-01-01
AC voltage frequency changes is one of the most important functions of solid state power converters. The most desirable features in frequency converters are the ability to generate load voltages with arbitrary amplitude and frequency, sinusoidal currents and voltages waveforms; the possibility of providing unity power factor for any load; and, finally, a simple and compact power circuit. Over the past decades, a number of different frequency converter topologies have appeared in the literature, but only the converters with either a voltage or current DC link are commonly used in industrial app
Schoenfeld, A. D.; Yu, Y.
1973-01-01
Versatile standardized pulse modulation nondissipatively regulated control signal processing circuits were applied to three most commonly used dc to dc power converter configurations: (1) the series switching buck-regulator, (2) the pulse modulated parallel inverter, and (3) the buck-boost converter. The unique control concept and the commonality of control functions for all switching regulators have resulted in improved static and dynamic performance and control circuit standardization. New power-circuit technology was also applied to enhance reliability and to achieve optimum weight and efficiency.
Transformerless dc-Isolated Converter
Rippel, Wally E.
1987-01-01
Efficient voltage converter employs capacitive instead of transformer coupling to provide dc isolation. Offers buck/boost operation, minimal filtering, and low parts count, with possible application in photovoltaic power inverters, power supplies and battery charges. In photovoltaic inverter circuit with transformerless converter, Q2, Q3, Q4, and Q5 form line-commutated inverter. Switching losses and stresses nil because switching performed when current is zero.
Optimum vector sequence for 3-phase AC/DC soft-switch converter control%三相AC/DC软开关变流器的最优矢量控制
孙孝峰; 刘裕华; 李长吾
2001-01-01
分析了矢量控制在三相变流器的应用,比较矢量圆的3种合成方式,得出了矢量控制的优化发波方式.考虑了开关信号中的谐振区间,以减小谐振环节对有效开关信号占空比丢失的影响.%This paper analysis the application of vector width pulse modulation in the paral- lel resonant DC link circuit control. Comparing three different synthesis methods of the vector circle, we have derived the optimum vector sequence for controlling the 3-phase AC/DC soft-switch converter, considering the resonant region in the switch signal to re- duce the influence of resonance to the lose of effective switch signal ratio.
Zumel, P.; Fernandez, C.; Sanz, M.; Lazaro, A.; Barrado, A.
2011-01-01
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…
Simulation and performance enhancement of the air cooling system in a DC/AC power converter station
Lozowy, R.; El-Shaboury, A.; Soliman, H.; Ormiston, S. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Mechanical and Manufacturing Engineering
2010-07-01
This study analyzed the flow structure and heat transfer in a large 3-dimensional domain with turbulence, mixed convection, an impinging jet, and flow over heated blocks. The objective was to better understand turbulent mixed-convection cooling of heat-generating bodies in 3-dimensional enclosures, which is important to industry. The cooling of 2 thyristor valve halls was simulated. Each valve hall housed 3 towers that contained electronics used in DC/AC power conversion. The simulation results included the magnitudes of the net air flows for all the inter-block gaps and the maximum temperature in each gap. A parametric study was also performed to investigate the effects of the air inlet location, size and aspect ratio. The effects of the air injection angle on cooling effectiveness was also examined. The study showed that for fixed inlet mass flow rate, significant improvement in the cooling effectiveness can be obtained by changing the injection angle of the inlet air jet, the location of the inlet grill, or the size of the inlet grill. It was concluded that these study results may be relevant to other applications, such as the design of power transformers, the design of cooling systems for spent nuclear fuel and computer server cooling racks. 13 refs., 12 figs.
Control of hybrid AC/DC microgrid under islanding operational conditions
Ding, G.; Gao, F.; Zhang, S.
2014-01-01
This paper presents control methods for hybrid AC/DC microgrid under islanding operation condition. The control schemes for AC sub-microgrid and DC sub-microgrid are investigated according to the power sharing requirement and operational reliability. In addition, the key control schemes...... of interlinking converter with DC-link capacitor or energy storage, which will devote to the proper power sharing between AC and DC sub-microgrids to maintain AC and DC side voltage stable, is reviewed. Combining the specific control methods developed for AC and DC sub-microgrids with interlinking converter......, the whole hybrid AC/DC microgrid can manage the power flow transferred between sub-microgrids for improving on the operational quality and efficiency....
Analytical Method to Calculate the DC Link Current Stress in Voltage Source Converters
Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus;
2014-01-01
The dc-link capacitor is one of the critical components, which influences the lifetime of the whole voltage source converter unit. For reliable design, the operating temperature of the dc-link capacitor should be known, which is primarily determined by the ambient temperature and the rms value...... of the current flowing through the dc-link capacitor. A simple analytical method to calculate the rms value of the dc-link capacitor current is presented in this paper. The effect of the line current ripple on the rms value of the dc-link capacitor current is considered. This yields accurate results, especially...
Zhou Yu-Fei(周宇飞); Tse C K; Qiu Shui-Sheng(丘水生); Chen Jun-Ning(陈军宁)
2005-01-01
This paper presents an improved resonant parametric perturbation method based on the modulation of a nonlinear map for controlling chaos. The control target can be any periodic orbit, which is not necessarily what is embedded in the chaotic attractor. Application of the method is illustrated for a common current-programmed DC/DC converter which has been known to easily become chaotic for a wide parameter range. The control effects of chaos are demonstrated with computer simulations.
Early Oscillation Detection for DC/DC Converter Fault Diagnosis
Wang, Bright L.
2011-01-01
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.
Analysis of energy processes in pulse converters of AC electric power
Kadatsky A.F.
2015-02-01
Full Text Available The article presents the analysis of energy processes in switched-mode AC-AC converters of buck, boost and buck-boost types. The mathematical model of energy processes is obtained. The mathematical model is generalized to DC-DC and AC-AC converters, to three basic types of converters and considers possibility of autotransformer inclusion of an inductor. It is shown that the use of bi-directional switches allows both DC and AC conversion of electrical energy regardless of the load type and also supports recuperation of electrical energy back to the source. It is shown that the maximum value of instant power in a load circuit in AC—AC converters exceeds twice the rated value of load power in comparison with DC—DC converters. It is shown that the energy capacity of an inductor in AC—AC converters exceeds twice the energy capacity of DC—DC converters at the identical rated power of conversion. It is shown that the energy capacity of an inductor in converters of buck and boost types depends on the ratio of input and output voltage. Also, the energy capacity of an inductor in converters of buck-boost type does not depend on the ratio of input and output voltage. It is shown that the energy capacity of an inductor in converters of buck and boost types is lower than the energy capacity of an inductor in the converter of buck-boost type.
R. Arulmurugan
2012-10-01
Full Text Available This paper proposes a new dc to dc boost converter using closed loop control proportional Integral and Derivative mechanism for photovoltaic (PV standalone high voltage applications. The boost converter is composed of MOSFETs which are driven by closed loop PWM control. Many advantages including high efficiency, minimum number of switch, high voltage and power, low cost. This converter is attractive for high voltage and high power applications. The analysis and design considerations of the converter are presented. A prototype was implemented for an application requiring a 410W output power, input voltage range from 17.1-V, and a 317-V output voltage. The proposed system efficiency is about 90%.
A single-phase embedded Z-source DC-AC inverter.
Kim, Se-Jin; Lim, Young-Cheol
2014-01-01
In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively.
An Efficient DC- DC Converter with Bidirectional Power Flow
N.RAJARAJESWARI
2008-07-01
Full Text Available This paper introduces a Bi-directional DC-DC converter with adaptive fuzzy logic controller. Bidirectional power flow is obtained by same power components and provides a simple, efficient, and galvanically isolated converter. In the presence of DC mains the converter operates as buck converter and charges the battery. When the DC mains fails, the converter operates as boost converter and the down stream converter is fed by the battery. The power switches are controlled by Pulse Width Modulation technique and the pulses are generated by the application of fuzzy logic with an adoption algorithm. The proposed converter is simulated using MATLAB and laboratory prototype was developed to validate the simulation results.
High-frequency high-voltage high-power DC-to-DC converters
Wilson, T. G.; Owen, H. A.; Wilson, P. M.
1982-01-01
A simple analysis of the current and voltage waveshapes associated with the power transistor and the power diode in an example current-or-voltage step-up (buck-boost) converter is presented. The purpose of the analysis is to provide an overview of the problems and design trade-offs which must be addressed as high-power high-voltage converters are operated at switching frequencies in the range of 100 kHz and beyond. Although the analysis focuses on the current-or-voltage step-up converter as the vehicle for discussion, the basic principles presented are applicable to other converter topologies as well.
On and off controlled resonant dc-dc power converter
2015-01-01
The present invention relates to a resonant DC-DC power converter comprising an input side circuit comprising a positive and a negative input terminal for receipt of an input voltage or current and an output side circuit comprising positive and negative output terminals for supply of a converter...... output voltage and connection to a converter load. The resonant DC-DC power converter further comprises a rectification circuit connected between an output of a resonant network and the output side circuit. The resonant network is configured for alternatingly being charged from the input voltage...... or current and discharged through the rectification circuit by a first controllable switch arrangement in accordance with a first switch control signal. A second controllable switch arrangement of the resonant DC-DC power converter is configured to select a first impedance characteristic of the resonant...
R dump converter without DC link capacitor for an 8/6 SRM: experimental investigation.
Kavitha, Pasumalaithevan; Umamaheswari, Bhaskaran
2015-01-01
The objective of this paper is to investigate the performance of 8/6 switched reluctance motor (SRM) when excited with sinusoidal voltage. The conventional R dump converter provides DC excitation with the help of capacitor. In this paper the converter used is the modified R dump converter without DC link capacitor providing AC or sinusoidal excitation. Torque ripple and speed ripple are investigated based on hysteresis current control. Constant and sinusoidal current references are considered for comparison in both DC and AC excitation. Extensive theoretical and experimental investigations are made to bring out the merits and demerits of AC versus DC excitation. It is shown that the constructionally simple SRM can be favorably controlled with simple R dump converter with direct AC excitation without need for DC link capacitor. A 4-phase 8/6 0.5 kW SRM is used for experimentation.
Coordinated Control Scheme for Ancillary Services from Offshore Wind Power Plants to AC and DC Grids
Sakamuri, Jayachandra N.; Altin, Müfit; Hansen, Anca Daniela;
2016-01-01
This paper proposes a new approach of providing ancillary services to AC and DC grids from offshore wind power plants (OWPPs), connected through multi-terminal HVDC network. A coordinated control scheme where OWPP’s AC grid frequency modulated according to DC grid voltage variations is used...... to detect and provide the ancillary service requirements of both AC and DC grids, is proposed in this paper. In particular, control strategies for onshore frequency control, fault ridethrough support in the onshore grid, and DC grid voltage control are considered. The proposed control scheme involves only...... local measurements and therefore avoids the need of communication infrastructure otherwise required for communication based control, and thus increases the reliability of the control system. The effectiveness of the proposed control scheme is demonstrated on a MTDC connected wind power system developed...
M. Hemachandran
2014-08-01
Full Text Available In this study multi port AC/DC-DC single stage power electronics converter proposed for grid power supply. The topology includes reduced number of active element and passive element. Passive element is used to provide to achieve improved voltage gain and to reduce the voltage stress of input side switches. The active-clamp circuits are used to recycle the energy stored in the leakage inductors and to improve the system performances. Here two input port (wind and battery unit and output port connected to dc grid, battery act as charge unit and source. Efficient wind power conversion is achieved by PFC boost dc-dc converter. Controlled and high step up voltage is supplied to multi-port converter from wind source.
Rusalin Lucian R. Păun
2008-05-01
Full Text Available This paper propose a new control technique forsingle – phase AC – AC converters used for a on-line UPSwith a good dynamic response, a reduced-partscomponents, a good output characteristic, a good powerfactorcorrection(PFC. This converter no needs anisolation transformer. A power factor correction rectifierand an inverter with the proposed control scheme has beendesigned and simulated using Caspoc2007, validating theconcept.
DC injection into low voltage AC networks
NONE
2005-07-01
This report summarises the results of a study investigating the impact of levels of injected DC current injections on a low voltage AC distribution network systems in order to recommend acceptable limits of DC from microgeneration. Relevant literature is reviewed, and the impact of DC levels in distribution transformers, transformer modelling, and instrumental transformers are discussed. The impact of DC in residual current devices (RCD) and in domestic electricity watt hour meters is examined along with DC enhanced corrosion, corrosion failure, and the measurement of DC current injection. Sources of DC injection outlined include DC from computer power supplies, network faults, geomagnetic phenomena, lighting circuits/dimmers, and embedded generators.
Schoenen, Timo
2011-07-01
Every time a new hybrid or electrical vehicle is developed, different topologies are compared to achieve the best results regarding weight costs and efficiency. The integration of a dc-to-dc converter between the battery stack and the power train is a frequently discussed alternative because the preferred voltage of the inverter and machine are often higher than the voltage of the battery stack. Within this thesis this approach was studied in detail and compared with the conventional concept without using a dc-to-dc converter. Therefore the influence of the dc-link voltage on the components like battery stack, machine, inverter and dc-to-dc converter was investigated. A change of the dc-link voltage leads to changes inside the components which affect weight, surface of the semiconductor devices and efficiency. This correlation could be used to develop a simulation process which optimizes the dc-link voltage regarding the programmed targets. In hybrid and electrical vehicles low weight and minimum costs are important and were defined as the main targets to achieve. The vantages which arise by using a dc-to-dc converter can be opposed to the disadvantages which also occur. The additional degree of freedom caused by the dc-to-dc converter shall be used. To achieve the best results regarding efficiency, the dc-link voltage has to be adapted to the operating point of the machine. First of all the dc-to-dc converter is an additional component with its weight, volume and losses. By the increased dc-link voltage on the drive train side, the size of the semiconductor devices inside the inverter could be reduced. Therefore the number of windings inside the machine has to be adapted accordingly. Also the wiring could be decreased based on the reduced currents. Overall there is still a higher weight and volume caused by the dc-to-dc converter. Also the efficiency map is influenced by the dc-to-dc converter. In the base speed region the dc-to-dc converter leads to a higher
Control of improved full-bridge three-level DC/DC converter for wind turbines in a DC grid
Deng, Fujin; Chen, Zhe
2013-01-01
transformer in the IFBTL dc/dc converter. A modulation strategy, including two operation modes, is proposed for the IFBTL dc/dc converter. Then, a voltage balancing control strategy is proposed for the IFBTL dc/dc converter. Furthermore, the control of the wind turbine based on the IFBTL dc/dc converter......This paper presents an improved full-bridge three-level (IFBTL) dc/dc converter for a wind turbine in a dc grid by inserting a passive filter into the dc/dc converter to improve the performance of the converter. The passive filter can effectively reduce the voltage stress of the medium frequency...... in a dc-grid system is presented. Finally, a small-scale IFBTL dc/dc converter prototype was built and tested in the laboratory, and the results verify the theoretical analysis....
Three-port DC-DC converter with new integrated transformer for DC Distribution Systems
Ouyang, Ziwei; Andersen, Michael A. E.
2014-01-01
A new integrated transformer for three-port dc-dc converter is proposed to overcome the power coupling effect existed in some known multiple inputs dc-dc converters. Orthogonal primary windings arrangement and in series connection of diagonal secondary Windings enables a fully power decoupling...
Application of Multi-port Bidirectional DC-DC Converter to Fuel Cell Vehicle Driving in JC08 Mode
Tanaka, Katsunori; Katayama, Noboru; Kogoshi, Sumio; Fukada, Takafumi; Ogawa, Makoto
A fuel cell-EDLC hybrid power system with a multi-port bidirectional DC-DC converter has been recently proposed for extending lifetime of a fuel cell due to smoothing the output current of the fuel cell. This paper studies the performance of the hybrid power system when a fuel cell vehicle drives in the JC08 mode using a simulation model. The simulation results indicate that even if the load current fluctuates, the output current of the fuel cell could be maintained at almost constant values with an assist from the EDLC although small spikes are observed.
Autonomous Operation of Hybrid Microgrid With AC and DC Subgrids
Chiang Loh, Poh; Li, Ding; Kang Chai, Yi
2013-01-01
This paper investigates on power-sharing issues of an autonomous hybrid microgrid. Unlike existing microgrids which are purely ac, the hybrid microgrid studied here comprises dc and ac subgrids interconnected by power electronic interfaces. The main challenge here is to manage power flows among all...... sources distributed throughout the two types of subgrids, which is certainly tougher than previous efforts developed for only ac or dc microgrid. This wider scope of control has not yet been investigated, and would certainly rely on the coordinated operation of dc sources, ac sources, and interlinking...... converters. Suitable control and normalization schemes are now developed for controlling them with the overall hybrid microgrid performance already verified in simulation and experiment....
Techniques for detecting proximity to voltage collapse in AC/DC systems
Canizares, Claudio A. [Escuela Politecnica Nacional, Quito (Ecuador); Long, Willis F.; Alvarado, Fernando L.; DeMarco, CChristopher L. [Wisconsin Univ., Madison, WI (United States)
1992-12-31
This paper describes three different techniques to detect proximity to voltage collapse (saddle-node bifurcation) in AC/DC systems; namely, direct (point of collapse) methods, continuation methods, and transient energy function methods. These techniques are compared among them, and also against the voltage sensitivity factor method using a 173 bus ac/dc test system. Various operational conditions are considered for this test system, so that transfer capabilities between areas and the effects of HVDC links can be analysed from the point of view of voltage collapse. 24 refs., 7 figs.
Early Oscillation Detection Technique for Hybrid DC/DC Converters
Wang, Bright L.
2011-01-01
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
A Novel FPSM Controller for DC-DC Switching Converters
Yong Feng; Shun-Ping Wang; Ping Luo; Quan-Ming Niu; Zhao-Ji Li
2007-01-01
This paper presents a novel fuzzy pulse skip modulation (FPSM) controller for switching direct current to direct current (DC-DC) converters based on fuzzy ratiocination modeling approach. Owing to the optimal consideration during the design and the nonlinear characteristics of the controller, improved dynamic responses of the FPSM controller can be achieved over conventional controllers. Compared with conventional proportion integral derivative (PID) control, FPSM control has 60% lower overshoot and 10% lower setting time under the same input voltage and output load change. The presented approach is general and can be applied to other types of DC-DC converters.
Charge pump DC-DC converter comprising solid state batteries
Reefman, D.; Roozeboom, F.; Notten, P.H.L.; Klootwijk, J.H.
2013-01-01
An electronic device is provided which comprises a DC-DC converter. The DC-DC converter comprises at least one solid-state rechargeable battery (B1, B2) for storing energy for the DC-DC conversion and an output capacitor (C2).
Simulation and Implementation of Quasi Resonant DC-DC Converter
N. Devarajan
2012-01-01
Full Text Available Problem statement: A half-bridge LLC resonant converter with a voltage doubler rectifier has a simple structure and its Zero-Voltage-Switching (ZVS capability is excellent from zero to full load condition. But conduction loss is more due to high circulating energy thus reducing the system efficiency. Moreover a variable frequency control method makes the control circuits more complicated than those using the Pulse Width Modulation (PWM control method. Thus, DC drive has lower efficiency when it operates on light loads. Approach: To improve the efficiency of the DC drive under light loads, a PWM-controlled quasi-resonant converter is proposed .It has simple control circuits and less conduction loss compared to a half-bridge LLC resonant converter under light load conditions. The proposed converter has a half-bridge LLC resonant converter along with an auxiliary circuit. The load regulation of the proposed converter can be achieved by an auxiliary circuit. Thus the proposed converter is expected to be suitable sustaining power module for the efficiency enhancement of DC drives. As the magnetizing inductance of the proposed converter is larger the circulating energy is considerably reduced under light load conditions. In this study the operational principle, design and modeling of QRC DC-DC converters for DC drives are presented. The PWM controlled quasi resonant converter is implemented using PIC microcontroller 16F184A. Results: The capacitor filter in the output is replaced by pi filter to produce DC with minimum ripple. The experimental results and simulation results are compared. This converter has the advantages like reduced number of switches, reduced transformer and filter size, reduced ripple, reduced switching losses, reduced switching stresses and increased power density. Conclusion: The experimental results closely agree with the simulation results.
Burns, W. W., III
1977-01-01
An analytically derived approach to the control of energy-storage dc-to-dc converters, which enables improved system performance and an extensive understanding of the manner in which this improved performance is accomplished, is presented. The control approach is derived from a state-plane analysis of dc-to-dc converter power stages which enables a graphical visualization of the movement of the system state during both steady state and transient operation. This graphical representation of the behavior of dc-to-dc converter systems yields considerable qualitative insight into the cause and effect relationships which exist between various commonly used converter control functions and the system performance which results from them.
Effect of DC Link Control Strategies on Multiterminal AC-DC Power Flow
Shagufta Khan
2015-01-01
Full Text Available For power-flow solution of power systems incorporating multiterminal DC (MTDC network(s, five quantities are required to be solved per converter. On the other hand, only three independent equations comprising two basic converter equations and one DC network equation exist per converter. Thus, for solution, two additional equations are required. These two equations are derived from the control specifications adopted for the DC links. Depending on the application, several combinations of valid control specifications are possible. Each combination of a set of valid control specifications is known as a control strategy. The number of control strategies increases with an increase in the number of the DC terminals or converters. It is observed that the power-flow convergence of integrated AC-MTDC power systems is strongly affected by the control strategy adopted for the DC links. This work investigates the mechanism by which different control strategies affect the power-flow convergence pattern of AC-MTDC power systems. To solve the DC variables in the Newton-Raphson (NR power-flow model, sequential method is considered in this paper. Numerous case studies carried out on a three-terminal DC network incorporated in the IEEE-300 bus test system validate this.
Optimization of Shielded PCB Air-Core Toroids for High-Efficiency DC-DC Converters
Orlandi, S; Buso, S; Michelis, S; Fuentes, C A; Kayal, M; Faccio, F; Spiazzi, G
2011-01-01
The paper describes the design of optimized printed circuit board (PCB) air-core toroids for high-frequency dc-dc converters with strict requirements in terms of volume and noise. The effect of several design parameters on the overall inductor volume, on dc and ac winding resistance, and on the radiated noise will be investigated. PCB toroids are compared to standard air-core solenoids and other state-of-the-art air-core toroids both theoretically and experimentally: at first, using ANSOFT Maxwell and ANSOFT Q3D simulation tools, and subsequently, with laboratory measurements (irradiated noise, efficiency, and frequency response) on several prototypes. These very flexible and rather easy to manufacture inductors appear very attractive for compact high-frequency dc-dc converters where high efficiency, low volume, and low noise are of primary concern.
Radiated electromagnetic emissions of DC-DC converters
Sammet, Jan Domenik
2010-01-01
A new powering scheme is considered to be mandatory for the CMS tracker at SLHC. The baseline solution of CMS foresees the use of DC-DC converters, allowing to provide larger currents while reducing losses. An important component of most converters are inductors, which, however, tend to radiate the switching noise generated by the converter. The radiated emissions of several converters have been measured and simulated. In addition noise susceptibility measurements with radiated noise and present CMS hardware have been performed. A summary of the results will be presented.
Digital model for harmonic interactions in AC/DC/AC systems
Guarini, A.P.; Rangel, R.D.; Pilotto, L.A.S.; Pinto, R.J.; Passos Junior, R. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)
1994-12-31
The main purpose of this paper is to present a model for calculation of HVdc converter harmonics taking into account the influence of the harmonic interactions between the ac systems in dc link transmissions. The ideas and methodologies used in the model development take into account the dc current ripple and ac voltage distortion in the ac systems. The theory of switching functions is applied to contemplate for the frequency conversions between the ac and dc sides, in an iterative process. It is possible then to obtain, even in balanced situations, non-characteristic harmonics that are produced by frequencies originated in the other terminal, which can be significant in a strongly coupled system, such as back-to-back configuration. (author) 9 refs., 3 figs.
2015-01-01
The present invention relates to a step-up DC-DC power converter which comprises a primary side circuit and a secondary side circuit coupled through a galvanic isolation barrier. The primary side circuit comprises a positive and a negative input terminal for receipt of an input voltage and an input...... being charged from the input voltage and discharged to the output capacitor through the galvanic isolation barrier in accordance with a switch control signal to produce the converter output voltage. The step-up DC-DC power converter comprises an electrical short-circuit connection across the galvanic...... capacitor coupled between the positive and negative input terminals and the secondary side circuit comprises an output capacitor chargeable to a converter output voltage between a first positive electrode and a second negative electrode. A switched energy storage network is configured for alternatingly...
Busquets-Monge, S.; Maheshwari, Ram Krishan; Munk-Nielsen, Stig
2013-01-01
are selected to obtain low weighted total harmonic distortion and a simple algorithm. A hexagonal-boundary compression factor is introduced to guarantee, at any operating point, dc-link capacitor voltage regulation capabilities in every switching cycle and avoid narrow gate pulses. The detailed PWM algorithm...... for an easy implementation in a digital control platform is also presented. The good performance of the strategy is verified through both simulation and experiments in a three-level threephase neutral-point clamped converter....
A Novel High Gain DC-DC Step up Converter
M. Al Mamun
2016-07-01
Full Text Available High gain dc-dc converters are widely used to maximize the energy harvest for renewable energy systems, for example, photovoltaic systems and fuel cell. Conventional boost converters usually operates at extreme duty cycle to obtain high voltage gain. Operation at extreme duty cycle leads to reverse recovery problem at the switches, high conduction loss, electromagnetic interference etc. This paper proposes a very high gain dc-dc step up converter operating at very low duty cycle (i.e. duty cycle <0.5. The additional advantage of the proposed converter is that a single control signal is used for the switches which reduces the operation complexity. The steady-state theoretical analysis described in this paper is finally verified by simulation results
New switching pattern for AC/AC converters with RB-IGBTs for offshore wind parks
Mogstad, Anne Berit
2008-01-01
Offshore wind power has an increasing interest in the research community and among the politicians. Therefore it is important to find the right solutions to meet the environmental and commercial requirements to give offshore wind power a promising future. This thesis are proposing a new converter topology for offshore wind parks. Since the topology is based on DC transmission in stead of AC transmission it is better suited for use in this type of parks. All the converters are located in the w...
An organic integrated capacitive DC-DC up-converter
Marien, H.; Steyaert, M.; Steudel, S.; Vicca, P.; Smout, S.; Gelinck, G.H.; Heremans, P.L.
2010-01-01
In this paper a fully integrated organic DC-DC upconverter is presented in a pentacene p-type only technology. This 3-stage Dickson converter reaches a voltage conversion factor of 3 for a purely capacitive load and 2.5 for a 10 μA load current. The maximal output voltage goes up to 75 V and the Dic
A direct power conversion topology for grid integrations of hybrid AC/DC resources
Liu, Xiong; Loh, Poh Chiang; Wang, Peng;
2012-01-01
This paper proposes a multiple-input versatile matrix converter (VMC) to integrate hybrid ac/dc energy resources and storages to a power grid. The VMC is developed based on the indirect matrix converter (IMC) with its six-switch voltage source converter replaced by a nine-switch topology. The nine...
Davari, Pooya; Zare, Firuz; Blaabjerg, Frede
2015-01-01
Generated harmonic current as a consequence of employing power electronics converter is known as an important power quality issue in distribution networks. From industry point of view complying with international standards is mandatory, however cost and efficiency are two other important features......, which need to be considered in order to be competitive in the market. Therefore, having a flexibility to meet various requirements imposed by the standard recommendations or costumer needs is at most desirable. This makes the generated harmonic current mitigation a challenging task especially with three......-phase diode bridge rectifier, which still is preferred in many power electronic systems. This paper addresses a novel current modulation strategy using a single-switch boost three-phase diode bridge rectifier. The proposed method can selectively mitigate current harmonics, which makes it suitable...
易映萍; 郭利辉; 刘普; 邓祥纯
2009-01-01
介绍了一种新型的单相有源逆变蓄电池回馈放电装置中DC/AC变换保护电路的设计方法,电路具有IGBT过流、过热、直流过压、输出交流过压、输出交流欠压、输出交流过流等多种保护类型,对从事电力电子技术特别是蓄电池放电技术研究的工程技术人员具有较高的参考价值.%This paper brings forward a new style of discharging device--single-phase active inverter battery feedback discharging device, the design method of DC/AC convert protection circuit is obtained. The circuit has multifold protection functions such as IGBT over-current and over thermal protection, DC over-voltage, AC over-voltage or low-voltage, output over-current, etc. This method will have high value for the engineers.
Wilson, T. G.
1981-11-01
Utilizing knowledge gained from past experience with experimental current-or-voltage step-up dc-to-dc converter power stages operating at output powers up to and in excess of 2 kW, a new experimental current-or-voltage step-up power stage using paralleled bipolar junction transistors (BJTs) as the controlled power switch, was constructed during the current reporting period. The major motivation behind the construction of this new experimental power stage was to improve the circuit layout so as to reduce the effects of stray circuit parasitic inductances resulting from excess circuit lead lengths and circuit loops, and to take advantage of the layout improvements which could be made when some recently-available power components, particularly power diodes and polypropylene filter capacitors, were incorporated into the design.
Kawa Adam
2014-09-01
Full Text Available The paper treats about main problems of one phase DC-AC microinverters that allow single solar cell to be joined with the grid. One of the issues is to achieve high voltage gain with high efficiency in DC circuit, which is necessary for proper operation of inverter. The operating principles, results of practical implementation and investigations on boost-flyback converter, which meets mentioned demands, are presented. (high step-up DC-DC boost-flyback converter for single phase grid microinverter
GaN Microwave DC-DC Converters
Ramos Franco, Ignacio
Increasing the operating frequency of switching converters can have a direct impact in the miniaturization and integration of power converters. The size of energy-storage passive components and the difficulty to integrate them with the rest of the circuitry is a major challenge in the development of a fully integrated power supply on a chip. The work presented in this thesis attempts to address some of the difficulties encountered in the design of high-frequency converters by applying concepts and techniques usually used in the design of high-efficiency power amplifiers and high-efficiency rectifiers at microwave frequencies. The main focus is in the analysis, design, and characterization of dc-dc converters operating at microwave frequencies in the low gigahertz range. The concept of PA-rectifier duality, where a high-efficiency power amplifier operates as a high-efficiency rectifier is investigated through non-linear simulations and experimentally validated. Additionally, the concept of a self-synchronous rectifier, where a transistor rectifier operates synchronously without the need of a RF source or driver is demonstrated. A theoretical analysis of a class-E self-synchronous rectifier is presented and validated through non-linear simulations and experiments. Two GaN class-E2 dc-dc converters operating at a switching frequency of 1 and 1.2 GHz are demonstrated. The converters achieve 80 % and 75 % dc-dc efficiency respectively and are among the highest-frequency and highest-efficiency reported in the literature. The application of the concepts established in the analysis of a self-synchronous rectifier to a power amplifier culminated in the development of an oscillating, self-synchronous class-E 2 dc-dc converter. Finally, a proof-of-concept fully integrated GaN MMIC class-E 2 dc-dc converter switching at 4.6 GHz is demonstrated for the first time to the best of our knowledge. The 3.8 mm x 2.6 mm chip contains distributed inductors and does not require any
Analysis of DC/DC Converter Efficiency for Energy Storage System Based on Bidirectional Fuel Cells
Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.
2013-01-01
Renewable energy sources are fluctuating depending on the availability of the energy source. For this reason, energy storage is becoming more important and bidirectional fuel cells represent an attractive technology. Fuel cells require highcurrent low-voltage dc-dc or dc-ac converters as power...
Radiated electromagnetic emissions of DC-DC converters
Feld, L; Jussen, R; Karpinski, W; Klein, K; Sammet, J; Wlochal, M, E-mail: sammet@cern.ch [Physikalisches Institut IB, RWTH Aachen University, Aachen (Germany)
2010-12-15
For the CMS tracker at SLHC a new powering scheme is considered to be mandatory to allow the detector to provide at least the same performance as today at the LHC. The baseline solution of CMS foresees the use of DC-DC converters to provide larger currents with smaller losses. An important component of most converters are inductors which, however, tend to radiate the switching noise generated by the converter. The emissions of different inductors have been measured and simulated, the coil design has been optimized and noise susceptibility measurements, with present CMS hardware, have been performed. This article summarizes the results.
Coordination Control Strategy for AC/DC Hybrid Microgrids in Stand-Alone Mode
Dwi Riana Aryani
2016-06-01
Full Text Available Interest in DC microgrids is rapidly increasing along with the improvement of DC power technology because of its advantages. To support the integration process of DC microgrids with the existing AC utility grids, the form of hybrid AC/DC microgrids is considered for higher power conversion efficiency, lower component cost and better power quality. In the system, AC and DC portions are connected through interlink bidirectional AC/DC converters (IC with a proper control system and power management. In the stand-alone operation mode of AC/DC hybrid microgrids, the control of power injection through the IC is crucial in order to maintain the system security. This paper mainly deals with a coordination control strategy of IC and a battery energy storage system (BESS converter under stand-alone operation. A coordinated control strategy for the IC, which considers the state of charge (SOC level of BESS and the load shedding scheme as the last resort, is proposed to obtain better power sharing between AC and DC subgrids. The scheme will be tested with a hybrid AC/DC microgrid, using the tool of the PSCAD/EMTDC software.
Direct Power Control Based Single-Phase AC-DC Converter Controller Design%基于直接功率控制的单相AC-DC变流器控制器设计
马庆安; 李群湛; 邱大强; 徐英雷; 张丽艳
2012-01-01
Single-phase AC-DC full-bridge converter is popular in industry. The aβ-coordinate model was setup for the single-phase system via delaying variables by 90°. Controller was designed based on direct power control. The two-degree-of-freedom PI controller was utilized in this paper to increase the robustness of the system and decrease the overshoot, and sampled voltages were modified to improve the performance. Simulation was conducted based on PSCAD/EMTDC, the results verify the feasibility.%将单相系统延迟90°得到αβ坐标系二相系统,并由此建立了单相变流器的数学模型。基于直接功率控制设计了单相变流器控制系统。提出电压外环使用二自由度PI控制器以提高控制系统的鲁棒性并降低系统启动过程中的超调量,对可能影响系统性能的采样电压进行了修正。最后基于PSCAD/EMTDC的仿真分析验证了方案的可行性。
Abdul kareem
2011-04-01
Full Text Available Both Soft computing based controllers and sliding mode controllers have been utilized to regulate the output voltage of dc-dc converters in response to changes in the load and the input voltage. Although both control techniques possess desirable characteristics, they have disadvantages which prevent them from being applied extensively. Many researchers have proposed the combination of sliding mode control and Soft computing based control to combine the advantages of both control techniques. In literature survey, it is found that the combination of the methods are proposed so that sliding mode algorithm is used in the design of Soft computing based controllers and the inputs to the controller are error and change in error and the inherent stability property of sliding mode controller is not utilized. This paper presents a novel soft computing based sliding mode controller in which inputs are switching function and change in switching function which combines the advantages of soft computing based controllers, sliding mode controllers and integral controllers. Since soft computing is used in the design of sliding mode controller, the stability of the proposed controller is assured. In addition, it is well suited for digital control design and implementation. The proposed controller has been designed for a buck converter and the controller is able to obtain the desired transient response without causing chattering and error under steady-state conditions. The proposed controller is able to give robust performance in terms of rejection to input voltage variations and load variations.
High power density dc/dc converter: Selection of converter topology
Divan, Deepakraj M.
1990-01-01
The work involved in the identification and selection of a suitable converter topology is described. Three new dc/dc converter topologies are proposed: Phase-Shifted Single Active Bridge DC/DC Converter; Single Phase Dual Active Bridges DC/DC Converter; and Three Phase Dual Active Bridges DC/DC Converter (Topology C). The salient features of these topologies are: (1) All are minimal in structure, i.e., each consists of an input and output bridge, input and output filter and a transformer, all components essential for a high power dc/dc conversion process; (2) All devices of both the bridges can operate under near zero-voltage conditions, making possible a reduction of device switching losses and hence, an increase in switching frequency; (3) All circuits operate at a constant frequency, thus simplifying the task of the magnetic and filter elements; (4) Since, the leakage inductance of the transformer is used as the main current transfer element, problems associated with the diode reverse recovery are eliminated. Also, this mode of operation allows easy paralleling of multiple modules for extending the power capacity of the system; (5) All circuits are least sensitive to parasitic impedances, infact the parasitics are efficently utilized; and (6) The soft switching transitions, result in low electromagnetic interference. A detailed analysis of each topology was carried out. Based on the analysis, the various device and component ratings for each topology operating at an optimum point, and under the given specifications, are tabulated and discussed.
马化盛; 张波; 郑健超; 梁少毅
2004-01-01
以AC/DC Buck-Boost PFC变换器为主拓扑,提出滑模变结构电流内环控制与PI调节器电压外环控制相结合的综合控制系统,以实现变换器高性能的单位功率因数校正.仿真和实验研究结果表明,这种控制系统设计兼有滑模控制动态性能、鲁棒性好与PI调节器稳定性好的优点.
Digital Control Technologies for Modular DC-DC Converters
Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon
2002-01-01
Recent trends in aerospace Power Management and Distribution (PMAD) systems focus on using commercial off-the-shelf (COTS) components as standard building blocks. This move to more modular designs has been driven by a desire to reduce costs and development times, but is also due to the impressive power density and efficiency numbers achieved by today's commercial DC-DC converters. However, the PMAD designer quickly learns of the hidden "costs" of using COTS converters. The most significant cost is the required addition of external input filters to meet strict electromagnetic interference (MIAMI) requirements for space systems. In fact, the high power density numbers achieved by the commercial manufacturers are greatly due to the lack of necessary input filters included in the COTS module. The NASA Glenn Research Center is currently pursuing a digital control technology that addresses this problem with modular DC-DC converters. This paper presents the digital control technologies that have been developed to greatly reduce the input filter requirements for paralleled, modular DC-DC converters. Initial test result show that the input filter's inductor size was reduced by 75 percent, and the capacitor size was reduced by 94 percent while maintaining the same power quality specifications.
Ouyang, Ziwei; Zhang, Zhe; Thomsen, Ole Cornelius;
2011-01-01
, hereby increasing the power density of converters. In this paper, a new planar integrated magnetics (PIM) module for a phase-shift plus duty cycle controlled hybrid bi-directional dc-dc converter is proposed, which assembles one boost inductor and two transformers into an E-I-E core geometry, reducing......In most power electronics converters, the overall volume is mainly determined by the number of parts and the size of passive components. Integrated magnetics and planar magnetics techniques therefore have been an excellent option in order to reduce the counts and the size of magnetic components...... the number of parts, the total volume of converter, as well as the total core loss of the magnetic components. AC losses in the windings and leakage inductance of the transformers are kept low by interleaving the primary and secondary turns of the transformers. To verify the validity of the design approach...
Optimization of DC-DC Converters via Geometric Programming
U. Ribes-Mallada
2011-01-01
Full Text Available The paper presents a new methodology for optimizing the design of DC-DC converters. The magnitudes that we take into account are efficiency, ripples, bandwidth, and RHP zero placement. We apply a geometric programming approach, because the variables are positives and the constraints can be expressed in a posynomial form. This approach has all the advantages of convex optimization. We apply the proposed methodology to a boost converter. The paper also describes the optimum designs of a buck converter and a synchronous buck converter, and the method can be easily extended to other converters. The last example allows us to compare the efficiency and bandwidth between these optimal-designed topologies.
New perspectives on the dynamics of AC and DC plasma arcs exposed to cross-fields
Abdo, Youssef; Rohani, Vandad; Cauneau, François; Fulcheri, Laurent
2017-02-01
Interactions between an arc and external fields are crucially important for the design and the optimization of modern plasma torches. Multiple studies have been conducted to help better understand the behavior of DC and AC current arcs exposed to external and ‘self-induced’ magnetic fields, but the theoretical foundations remain very poorly explored. An analytical investigation has therefore been carried out in order to study the general behavior of DC and AC arcs under the effect of random cross-fields. A simple differential equation describing the general behavior of a planar DC or AC arc has been obtained. Several dimensionless numbers that depend primarily on arc and field parameters and the main arc characteristics (temperature, electric field strength) have also been determined. Their magnitude indicates the general tendency pattern of the arc evolution. The analytical results for many case studies have been validated using an MHD numerical model. The main purpose of this investigation was deriving a practical analytical model for the electric arc, rendering possible its stabilization and control, and the enhancement of the plasma torch power.
Operation and Control of Grid Connected Hybrid AC/DC Microgrid using various RES
Kodanda Ram R B P U S B
2014-10-01
Full Text Available This paper proposes a Hybrid AC/DC Microgrid in alliance with Photo Voltaic (PV energy, Wind Energy and Proton Exchange Membrane (PEM Fuel cells. Microgrids are becoming increasingly attractive to the researchers because of the less greenhouse gases, low running cost, and flexibility to operate in connection with utility grid. The Hybrid AC/DC Microgrid constitutes independent AC and DC subgrids, where all the corresponding sources and loads are connected to their respective buses and these buses are interfaced using an interfacing converter. The Hybrid AC/DC Microgrid increases system efficiency by reducing the multiple reverse conversions involved in conventional RES integration to grid. A Small Hybrid AC/DC Microgrid in grid connected mode was modeled and simulated in MATLAB-SIMULINK environment. The simulation results proves the stable operation considering the uncertainty of generations and loads.
Fuangpian Phanupong
2016-01-01
Full Text Available Nowadays, using of High Voltage Direct Current (HVDC transmission to maximize the transmission efficiency, bulk power transmission, connection of renewable power source from wind farm to the grid is of prime concern for the utility. However, due to the high electric field stress from Direct Current (DC line, the corona discharge can easily be occurred at the conductor surface leading to transmission loss. Therefore, the polarity effect of DC lines on corona inception and breakdown voltage should be investigated. In this work, the effect of DC polarity and Alternating Current (AC field stress on corona inception voltage and corona discharge is investigated on various test objects, such as High Voltage (HV needle, needle at ground plane, internal defect, surface discharge, underground cable without cable termination, cable termination with simulated defect and bare overhead conductor. The corona discharge is measured by partial discharge measurement device with high-frequency current transformer. Finally, the relationship between supply voltage and discharge intensity on each DC polarity and AC field stress can be successfully determined.
Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja
2014-09-09
A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.
Bahler, D. D.
1978-01-01
Procedures are presented for obtaining valid frequency-domain transfer functions of regulated reactor energy-storage dc-to-dc converters. These procedures are for measuring loop gain, closed loop gain, output impedance, and audio susceptibility. The applications of these measurements are discussed.
陈鹏; 傅鹏; 宋执权
2011-01-01
In response to the current imbalance phenomenon and its harmfulness, a current sharing circuit model is built up, which reveals the underlying causes for the current imbalance through a quantitative analysis. Then, a feasible approach of improvement, namely enlargement of the length of connection busbars, is proposed. After the amendment, it can be seen that the current sharing coefficient is ahnost unity under rated or fault current conditions.
Low dose failures of hardened DC-DC power converters
Lehman, J.; Yui, C.; Rax, B. G.; Miyahira, T. F.; Weideman, M.; Schrick, P.; Swift, G. M.; Johnston, A. H.
2002-01-01
Box-level total dose testing of the FOG (Fiber Optic Gyro) by IXSEA at ESA's GammabeamFacility were abruptly terminated at 8krad (Si) due to catastrophic failure (complete shutdown). This was unexpected because all components within the gyro were supposedly radiation tolerant. Further testing showed that the components responsible for the failure were two DC-DC converters, manufactured by Interpoint, that stopped regulating shortly before shutdown. This paper summarizes diagnostic test results for the converters to determine the underlying cause of the unexpected failure at low levels of radiation.
Bi-Directional DC-DC Converter for PHEV Applications
Abas Goodarzi
2011-01-31
Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.
Study on a Novel Half-bridge Single-phase PFC AC/DC Buck Converter%新颖的半桥式单相PFC AC/DC Buck变换器的研究
谢仁践; 张波
2002-01-01
提出了一种新颖的基于电感电压控制模式(IVC)的半桥式单相PFC AC/DC Buck PWM变换器,它具有电路结构简单、控制性能好、功率因数为1的优点.分析了该电路的主要工作原理和IVC控制策略,详细分析了其主要设计参数,最后利用等效平均模型方法对其工作特性进行了仿真研究,仿真和实验验证了理论研究的结果.
SIMA Wenxia; ZHOU Yuan; YUAN Tao; YANG Qing; SUN Shujie; Gilles Tremouille
2012-01-01
For AC and DC hybrid transmission lines, the arrangement and transposition modes of AC conductors not only affect the unbalance factor of AC lines, but also influence the bias current of DC converter transformers by AC and DC coupling. Excessive bias current will influence the normal operation of converter transformers, thus the optimal AC phase arrangement and transposition mode of hybrid lines was studied to minimize the coupling effect between AC and DC lines to fit the requirements on both aspects. Based on the parameters of the Ximeng-Shanghai project in China, a detailed simulation model of the DC converter station and the hybrid transmission line with double- circuit AC 500 kV transmission lines and DC ± 800 kV transmission lines were presented in the software PSCAD- EMTDC, and the coupling effects of the hybrid transmission lines were elucidated. The fundamental frequency components of DC poles with different operation conditions, arrangements of conductors and operation modes were analyzed, and the effective arrangement and transposition limiting the fundamental frequency current component of the DC line were compared. Simulation results show that AC operating conditions can affect DC induced components while the DC system operation mode has no apparent effect. With compact arrangement and inconsistent transposition of AC lines, the fundamental frequency component on DC lines can be reduced effectively; the three transposed mode within the hybrid line is the optimal layout scheme, considering both the requirements of DC bias current and AC unbalance degree.
Power flow analysis for droop controlled LV hybrid AC-DC microgrids with virtual impedance
Li, Chendan; Chaudhary, Sanjay; Vasquez, Juan Carlos
2014-01-01
The AC-DC hybrid microgrid is an effective form of utilizing different energy resources and the analysis of this system requires a proper power flow algorithm. This paper proposes a suitable power flow algorithm for LV hybrid AC-DC microgrid based on droop control and virtual impedance. Droop...... and virtual impedance concepts for AC network, DC network and interlinking converter are reviewed so as to model it in the power flow analysis. The validation of the algorithm is verified by comparing it with steady state results from detailed time domain simulation. The effectiveness of the proposed...
陈强; 郝思鹏; 章心因; 吕干云
2016-01-01
以三相DC/AC变流器为研究对象，给出了一种无锁相环直接功率预测控制方法，能实现对并网功率的无差拍控制，并且为降低锁相环对控制性能的影响，实现无锁相环控制。根据采样控制导致的两拍延时，采样控制频率为载波频率两倍，精确计算得到下一拍的变流器状态量，然后针对给定功率参考值根据公式直接计算得到三相变流电路的输出。推导得到控制系统设定的频率与电网频率的偏差对所提出控制方法的性能没有影响，论证了无锁相环的可行性。最后构建了三相并网变流器Simulink仿真模型和实验样机，利用Simulink中的Embedded Coder模块实现控制系统仿真模型到DSP硬件控制系统C语言程序的转换，通过仿真和实验验证了控制方法的有效性。%A predictive direct power control method without the phase locked loop (PLL) is presented,the research obj ect of which is the three-phase DC/AC converter.This method can achieve the deadbeat control of grid-connected power.In order to reduce the influence on the control performance by PLL,the method without PLL is realized.According to the two-beat delay resulting from the sampling control,the sampling frequency which is twice the carrier frequency is adopted to calculate the grid voltage,the grid-connected power and current after one cycle accurately.The output of the converter is calculated by the formula given in the paper.The deviation between the frequency set by the control system and the grid frequency has no influence on the performance of the control method proposed in this paper.The feasibility of the absence of phase locked loop (PLL) is demonstrated.The three-phase grid-connected converter simulation model and experimental prototype are built.The conversion from a control system simulation model into the C language program of DSP is realized by the Embedded Coder block of Simulink.The control method is validated and
Silveira, George Cajazeiras [Centro Federal de Educacao Tecnologica do Ceara (CEFET/CE), Fortaleza, CE (Brazil); Torrico-Bascope, Rene P. [Universidade Federal do Ceara (PPGEE/UFC), Fortaleza, CE (Brazil). Programa de Pos Graduacao em Engenharia Eletrica; Borges Neto, Manuel Rangel [Centro Federal de Educacao Tecnologica de Petrolina (CEFET-PET), PE (Brazil)
2008-07-01
A non-isolated DC-AC converter with high voltage gain with two output sinusoidal voltage - 110 V and 220 V - and frequency 60 Hz for application in autonomous systems of electric power is proposed in this work. This topology consists of a boost converter with high voltage gain, based on three-state switching cell combined with a double half bridge inverter. This configuration type the size and the cost are reduced and the efficiency is gotten better, due to the reduced number of switches. The converters that compose this topology operate with high frequency, reducing the volume of the magnetic materials. can be mention as important characteristics: the voltage stress across the switches of the boost converter are low, due they be naturally clamped by one output filter capacitor, which allows the utilization of switches with lower conduction resistances, and the waveforms of the output voltage of the double half bridge inverter supplies for the load it is sinusoidal and it possesses low harmonic content. (author)
Studies of Interleaved DC-DC Boost Converters with Coupled Inductors
2011-04-01
power density requirements, interleaved buck and boost converters have been studied in recent years for their potential to improve power converter ...duty ratio of switch S1. Figure 1: Conventional DC-DC Boost Converter Topology (1) Vout/Vin...interleaved DC-DC boost converters with coupled inductors. Included are discussions on a 10kW prototype, a 2kW high temperature prototype, and two 2kW
High Current Planar Transformer for Very High Efficiency Isolated Boost DC-DC Converters
Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.
2014-01-01
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 a......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...
A Survey on Voltage Boosting Techniques for Step-Up DC-DC Converters
Forouzesh, Mojtaba; Siwakoti, Yam Prasad; Gorji, Saman Asghari;
2016-01-01
Step-up dc-dc converters are used to boost the voltage level of the input to a higher output level. Despite of its features such as simplicity of implementation, the fundamental boost dc-dc converter has shortcomings such as low boost ability and low power density. With these limitations, researc...
A Direct Power Conversion Topology for Grid Integration of Hybrid AC/DC Energy Resources
Liu, Xiong; Loh, Poh Chiang; Wang, Peng;
2013-01-01
This paper proposes a multiple-input versatile matrix converter (VMC) for integrating hybrid ac/dc energy resources and storages to the power grid. The VMC is developed from the traditional indirect matrix converter but operates in the reverse-boost mode rather than in the forward-buck mode. The ...
Development of a standardized control module for dc-to-dc converters
Yu, Y.; Iwens, R. I.; Lee, F. C.; Inouye, L. Y.
1977-01-01
The electrical performance of a power processor depends on the quality of its control system. Most of the existing control circuits suffer one or more of the following imperfections that tend to restrict their respective utility: (1) inability to perform different modes of duty cycle control; (2) lack of immunity to output filter parameter changes, and (3) lack of capability to provide power component stress limiting on an instantaneous basis. The three lagging aspects of existing control circuits have been used to define the major objectives of the current Standardized Control Module (SCM) Program. Detailed information on the SCM functional block diagram, its universality, and performance features, circuit description, test results, and modeling and analysis efforts are presented.
User's design handbook for a Standardized Control Module (SCM) for DC to DC Converters, volume 2
Lee, F. C.
1980-01-01
A unified design procedure is presented for selecting the key SCM control parameters for an arbitrarily given power stage configuration and parameter values, such that all regulator performance specifications can be met and optimized concurrently in a single design attempt. All key results and performance indices, for buck, boost, and buck/boost switching regulators which are relevant to SCM design considerations are included to facilitate frequent references.
全数字控制单相AC-DC功率电路设计%Digital Control Single Phase AC-DC Converter Design
郑建福; 陈伟凡; 毛行奎
2014-01-01
针对功率因数、效率、电压、电流等关键指标,以dsPIC33FJ16GS502单片机为控制器,采用单相全桥PWM整流和Buck两级拓扑结构,设计了全数字控制单相AC-DC功率电路.同时具有测量功率因数和输出电流大于2.5A时过载保护功能,还能实现输入功率因数可调.通过试验测试结果证明系统指标满足设计要求.
Adapting AC Lines to DC Grids for Large-Scale Renewable Power Transmission
D. Marene Larruskain
2014-10-01
Full Text Available All over the world, governments of different countries are nowadays promoting the use of clean energies in order to achieve sustainable energy systems. In this scenario, since the installed capacity is continuously increasing, renewable sources can play an important role. Notwithstanding that, some important problems may appear when connecting these sources to the grid, being the overload of distribution lines one of the most relevant. In fact, renewable generation is usually connected to the nearest AC grid, although this HV system may not have been designed considering distributed generation. In the particular case of large wind farms, the electrical grid has to transmit all the power generated by wind energy and, as a consequence, the AC system may get overloaded. It is therefore necessary to determine the impact of wind power transmission so that appropriate measures can be taken. Not only are these measures influenced by the amount of power transmitted, but also by the quality of the transmitted power, due to the output voltage fluctuation caused by the highly variable nature of wind. When designing a power grid, although AC systems are usually the most economical solution because of its highly proven technology, HVDC may arise in some cases (e.g. offshore wind farms as an interesting alternative, offering some added values such as lower losses and better controllability. This way, HVDC technology can solve most of the aforementioned problems and has a good potential for future use. Additionally, the fast development of power electronics based on new and powerful semiconductor devices allow the spread of innovative technologies, such as VSC-HVDC, which can be applied to create DC grids. This paper focuses on the main aspects involved in adapting the existing overhead AC lines to DC grids, with the objective of improving the transmission of distributed renewable energy to the centers of consumption.
A new high performance DC/AC converter inverse%一种新型高性能DC/AC逆换器
李峰; 任继锋; 朱音璇
2014-01-01
在比较不同DC/AC逆变器的基础上,以单相全桥逆变电路为主拓扑结构,设计了一款高性能逆变器.该逆变器采用推挽升压和全桥逆变两级变换,主控回路采用STC89C52单片机,前级推挽升压电路采用SG3525芯片控制,闭环反馈,逆变部分采用IR2110芯片进行全桥逆变,运用U3990F6芯片完成对SPWM波的调制,功率驱动元件使用IRF540,数模转换采用ADC0832芯片,后级输出采用电流互感器进行采样反馈,形成双重反馈环节,增加了逆变器的稳定性.最后输出的交流电压通过AD637有效值转换后,再由STC89C52单片机的控制进行模数转换,最终将电压值显示到液晶12864上,形成了良好的人机界面.
Zero-voltage switching technique in dc/dc converters
Liu, Kwang-Hwa; Lee, Fred C. Y.
1990-07-01
A novel resonant switch operating under the principle of zero-voltage switching is presented. In contrast to the zero-current switching, this technique eliminates the switching loss and dv/dt noise due to the discharging of MOSFET junction capacitances and the reverse recovery of diodes, and enables the converters to operate at high frequencies. A dc analysis of the converter is carried out. The duality relationship between the zero-current switching technique and the zero-voltage switching technique is derived. The two techniques are compared using an example showing the duality between a current-mode quasi-resonant Buck converter and a voltage-mode quasi-resonant boost converter. A 5-MHz 50 V to 5 V flyback converter employing the zero-voltage switching technique has been implemented. The circuit contains the smallest number of components possible, and yet maintains high efficiency at high switching frequency.
Onar, Omer C [ORNL
2011-01-01
This study presents a bi-directional multi-level power electronic interface for the grid interactions of plug-in hybrid electric vehicles (PHEVs) as well as a novel bi-directional power electronic converter for the combined operation of battery/ultracapacitor hybrid energy storage systems (ESS). The grid interface converter enables beneficial vehicle-to-grid (V2G) interactions in a high power quality and grid friendly manner; i.e, the grid interface converter ensures that all power delivered to/from grid has unity power factor and almost zero current harmonics. The power electronic converter that provides the combined operation of battery/ultra-capacitor system reduces the size and cost of the conventional ESS hybridization topologies while reducing the stress on the battery, prolonging the battery lifetime, and increasing the overall vehicle performance and efficiency. The combination of hybrid ESS is provided through an integrated magnetic structure that reduces the size and cost of the inductors of the ESS converters. Simulation and experimental results are included as prove of the concept presenting the different operation modes of the proposed converters.
DC Voltage Droop Control Implementation in the AC/DC Power Flow Algorithm: Combinational Approach
Akhter, F.; Macpherson, D.E.; Harrison, G.P.
2015-01-01
of operational flexibility, as more than one VSC station controls the DC link voltage of the MTDC system. This model enables the study of the effects of DC droop control on the power flows of the combined AC/DC system for steady state studies after VSC station outages or transient conditions without needing...... to use its complete dynamic model. Further, the proposed approach can be extended to include multiple AC and DC grids for combined AC/DC power flow analysis. The algorithm is implemented by modifying the MATPOWER based MATACDC program and the results shows that the algorithm works efficiently.......In this paper, a combinational AC/DC power flow approach is proposed for the solution of the combined AC/DC network. The unified power flow approach is extended to include DC voltage droop control. In the VSC based MTDC grids, DC droop control is regarded as more advantageous in terms...
Study of nonlinear phenomena in switching DC/DC converters
Iu, Herbert Ho-Ching
This thesis studies some nonlinear phenomena such as bifurcation and chaos in DC/DC switching converters. Five phases of investigations are described. The first phase reviews the existing tools for analyzing nonlinear systems that are helpful to the investigation of nonlinear phenomena in power electronic circuits. Some of these existing tools are employed to study the nonlinear behaviour of power electronic circuits in the subsequent phases. The second phase focuses on the analysis of bifurcation behaviour of parallel-connected DC/DC converters under a master-slave current sharing scheme. An iterative discrete-time map and its Jacobian are established to predict the onset of period-doubling or Neimark-Sacker bifurcation. Both parallel-connected buck converters and boost converters are studied. The third phase studies an autonomous free-running Cuk converter under a hysteretic current-mode control. Hopf bifurcation is observed, for the first time, in this kind of autonomous power electronic circuits. The method of state-space averaging is employed to predict the occurrence of such bifurcation. Extensive simulations and experiments confirm the predicted results. A typical bifurcation sequence from stable fixed points to chaos, via limit cycles and quasiperiodic orbits, is demonstrated. The fourth phase investigates the possibility of synchronization of two chaotic autonomous free-running Cuk converters. With a particular capacitor voltage as driving signal, synchronization is found possible. Averaged state equations and conditional Lyapunov exponents are used to predict the possibility of synchronization while computer simulations and PSPICE simulations provide the verification. The last phase gives suggestions for future research.
Wang, Haojie; Han, Minxiao; Yan, Wenli
2016-01-01
It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC) is proposed for stor......It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC) is proposed...... for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load...
Energy Factor and Mathematical Modeling for Power DC/DC Converters
Fang Lin LUO; Hong YE
2004-01-01
Mathematical modelling for power DC/DC converters is a historical problem accompanying DC/DC conversion technology since 1940's. The traditional mathematical modelling is not available for complex structure converters since the differential equation order increases very high. We have to search other way to establish mathematical modelling for power DC/DC converters. We have theoretically defined a new concept - Energy Factor (EF) in this paper and researched the relations between EF and the mathematical modelling for power DC/DC converters. EF is a new concept in power DC/DC conversion technology, which thoroughly differs from the traditional concepts such as power factor (PF), power transfer efficiency (η), total harmonic distortion (THD) and ripple factor (RF). EF and the subsequential EFv (and EFvD ) can illustrate the system stability, reference response and interference recovery. This investigation is very helpful for system design and DC/DC converters characteristics foreseeing. Two DC/DC converters: Buck converter and Super-Lift Luo-Converter as the samples are analysed in this paper to demonstrate the applications of EF, EFv (and EFvD), PE,SE, VE (and VED ), time constant τ and damping time constant τd .
Power Network impedance effects on noise emission of DC-DC converters
Esteban, M. C.; Arteche, F.; Iglesias, M.; Gimeno, A.; Arcega, F. J.; Johnson, M.; Cooper, W. E.
2012-01-01
The characterization of electromagnetic noise emissions of DC-DC converters is a critical issue that has been analyzed during the desing phase of CMS tracker upgrade. Previous simulation studies showed important variations in the level of conducted emissions when DC-DC converters are loaded/driven by different impedances and power network topologies. Several tests have been performed on real DC-DC converters to validate the Pspice model and simulation results. This paper presents these test results. Conducted noise emissions at the input and at the output terminals of DC-DC converters has been measured for different types of power and FEE impedances. Special attention has been paid to influence on the common-mode emissions by the carbon fiber material used to build the mechanical structure of the central detector. These study results show important recommendations and criteria to be applied in order to decrease the system noise level when integrating the DC-DC.
Three Phase Resonant DC Power Converter for Ion Thrusters Project
National Aeronautics and Space Administration — Our phase 1 study has revealed many significant benefits of a new class of DC-to-DC power converters with performance that cannot be matched by current flight power...
Very High Frequency Half Bridge DC/DC Converter
Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.
2014-01-01
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...
Mostaan, Ali; Alizadeh, Ebrahim; Soltani, Mohsen
2014-01-01
Novel step-up DC/DC converter is introduced in this paper. This converter is realized with adding the switched capacitor voltage multiplier cell to the three switch step-down DC/DC converter that has been proposed in the literature. The proposed converter is analyzed in the steady state and the v...
Manners, B.; Gholdston, E. W.; Karimi, K.; Lee, F. C.; Rajagopalan, J.; Panov, Y.
1996-01-01
As space direct current (dc) power systems continue to grow in size, switching power converters are playing an ever larger role in power conditioning and control. When designing a large dc system using power converters of this type, special attention must be placed on the electrical stability of the system and of the individual loads on the system. In the design of the electric power system (EPS) of the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) and its contractor team led by Boeing Defense & Space Group has placed a great deal of emphasis on designing for system and load stability. To achieve this goal, the team has expended considerable effort deriving a dear concept on defining system stability in both a general sense and specifically with respect to the space station. The ISS power system presents numerous challenges with respect to system stability, such as high power, complex sources and undefined loads. To complicate these issues, source and load components have been designed in parallel by three major subcontractors (Boeing, Rocketdyne, and McDonnell Douglas) with interfaces to both sources and loads being designed in different countries (Russia, Japan, Canada, Europe, etc.). These issues, coupled with the program goal of limiting costs, have proven a significant challenge to the program. As a result, the program has derived an impedance specification approach for system stability. This approach is based on the significant relationship between source and load impedances and the effect of this relationship on system stability. This approach is limited in its applicability by the theoretical and practical limits on component designs as presented by each system segment. As a result, the overall approach to system stability implemented by the ISS program consists of specific hardware requirements coupled with extensive system analysis and hardware testing. Following this approach, the ISS program plans to begin
Topological variations of the inverse dual converter for high-power dc-dc distribution systems
Ehsani, Mehrdad; Laskai, Laszlo
New dc-to-dc converter topologies are presented which are suitable for high density high power supplies. Topological variations of the basic inverse dual converter (IDC) circuit such as the transformer coupled, the multiphase and the multipulse derivation of the single phase IDC have been analyzed and some simulation results have been presented. The single phase IDC offers a buck-boost operation over wide range without transformer, bidirectional power flow, and complementary commutation of the switches. The topologies examined in this paper have additional features such as lower device and component stresses, and smaller filter requirements, resulting in smaller size and weight. Some performance and possible applications are also examined. IDCs for serial and parallel power distribution, and ac tapping of the IDC are discussed.
RESONANT STEP-DOWN DC-DC POWER CONVERTERS
2015-01-01
charged from the input voltage and discharged to the output capacitor through the galvanic isolation barrier by a semiconductor switch arrangement in accordance with a switch control signal to produce the converter output voltage. The resonant step-down DC-DC power converter comprises an electrical short...... of the primary side circuit thereby establishing in both the first and second cases a series coupling of the output capacitor and the input capacitor. A load connection is established, in the first case, between the first positive electrode of the output capacitor and the positive input terminal or......-circuit connection across the galvanic isolation barrier connecting, in a first case, the second negative electrode of the output capacitor to the positive input terminal of the primary side circuit or, in a second case, connecting the second positive electrode of the output capacitor to the negative input terminal...
A high voltage ratio and low ripple interleaved DC-DC converter for fuel cell applications.
Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih
2012-01-01
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.
Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller
Sreenivasappa Veeranna Bhupasandra
2010-01-01
Full Text Available 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 PWM controller.
DC/DC converter with improved rectification for higher efficiency
Maisel, Peter; Saliternig, Martin [Continental AG, Nuernberg (Germany)
2010-07-01
High-power dc-dc converters are an important element of the electrical system of electric vehicles and hybrid electric vehicles. These complex modular components provide the link between the high-voltage level used for the powertrain and the low-voltage bus for the lighting system, engine management and auxiliary needs in the vehicle. The essential requirements for all converters are high efficiency, compact size, lightweight and reliability. A very popular method to increase the efficiency is the synchronous rectification. Parasitic inductances in the commutation circuit and reverse recovery effects can produce a ringing with voltage overshoots at the diodes and the transistors. These spikes can cause higher average power dissipation in the seminconductors and higher EMI (electromagnetic interference).
Chaos analysis and chaotic EMI suppression of DC-DC converters
Zhang, Bo
2014-01-01
Introduces chaos theory, its analytical methods and the means to apply chaos to the switching power supply design DC-DC converters are typical switching systems which have plenty of nonlinear behaviors, such as bifurcation and chaos. The nonlinear behaviors of DC-DC converters have been studied heavily over the past 20 years, yet researchers are still unsure of the practical application of bifurcations and chaos in switching converters. The electromagnetic interference (EMI), which resulted from the high rates of changes of voltage and current, has become a major design criterion in DC-DC co
Simulation and Implementation of Interleaved Boost DC-DC Converter for Fuel Cell Application
Ahmad Saudi Samosir
2011-10-01
Full Text Available This paper deals with a boost dc-dc converter for fuel cell application. In fuel cell electric vehicles application, a high power boost dc-dc converter is adopted to adjust the output voltage, current and power of fuel cell engine to meet the vehicle requirements. One of challenge in designing a boost converter for high power application is how to handle the high current at the input side. In this paper an interleaved boost dc-dc converter is proposed for current sharing on high power application. Moreover, this converter also reduces the fuel ripple current. Performance of the interleaved boost converter is tested through simulation and experimental results. Keywords: component; Interleaved Boost Converter; Fuel Cell Electric Vehicle; high power application.
Analysis of high voltage step-up nonisolated DC-DC boost converters
Alisson Alencar Freitas, Antônio; Lessa Tofoli, Fernando; Junior, Edilson Mineiro Sá; Daher, Sergio; Antunes, Fernando Luiz Marcelo
2016-05-01
A high voltage step-up nonisolated DC-DC converter based on coupled inductors suitable to photovoltaic (PV) systems applications is proposed in this paper. Considering that numerous approaches exist to extend the voltage conversion ratio of DC-DC converters that do not use transformers, a detailed comparison is also presented among the proposed converter and other popular topologies such as the conventional boost converter and the quadratic boost converter. The qualitative analysis of the coupled-inductor-based topology is developed so that a design procedure can be obtained, from which an experimental prototype is implemented to validate the theoretical assumptions.
陈厚合; 李国庆; 姜涛
2011-01-01
The transformation strategy among converter control modes is analyzed. Considering the interaction effects between AC and DC system under different converter control modes, a new power flow algorithm that can suitable for the transformation strategy of converter control modes is proposed. Based on the sequential solution, the elements of special nodes in Jacobian matrix of AC system are effectively modified; in the transformation strategy based on converter control modes the key state variables of converter are reasonably chosen and the product of the cosine value of the control angle with the transformation ratio of transformer tap is processes as one state variable to effectively avoid the off-limit of cosine value of the control angle or that of transformer tap during the iteration. The proposed algorithm is mathematically clear and easy to achieve. Simulation results show that the proposed algorithm is accurate, rapid and reliable.%分析了换流器控制方式的转换策略。考虑在不同控制方式下交直流系统的相互影响，提出一种能够满足换流器控制方式转换策略的潮流计算方法。以顺序求解法为基础，对交流系统雅可比矩阵的特殊节点元素进行有效修正；基于换流器控制方式转换策略合理选取换流器关键状态变量，并将控制角余弦值和变压器分接头变比乘积作为一个状态变量处理，有效地避免了迭代过程中控制角余弦值或变压器分接头越限情况发生。该算法数学概念清晰、易于实现。仿真结果验证了该算法的准确性、快速性和可靠性。
Interleaved DC-DC Converter with Discrete Duty Cycle and Open Loop Control
Kroics, K.; Sokolovs, A.
2016-08-01
The authors present the control principle of the multiphase interleaved DC-DC converter that can be used to vastly reduce output current ripple of the converter. The control algorithm can be easily implemented by using microcontroller without current loop in each phase. The converter works in discontinuous conduction mode (DCM) but close to boundary conduction mode (BCM). The DC-DC converter with such a control algorithm is useful in applications that do not require precise current adjustment. The prototype of the converter has been built. The experimental results of the current ripple are presented in the paper.
Interleaved DC-DC Converter with Discrete Duty Cycle and Open Loop Control
Kroics K.
2016-08-01
Full Text Available The authors present the control principle of the multiphase interleaved DC-DC converter that can be used to vastly reduce output current ripple of the converter. The control algorithm can be easily implemented by using microcontroller without current loop in each phase. The converter works in discontinuous conduction mode (DCM but close to boundary conduction mode (BCM. The DC-DC converter with such a control algorithm is useful in applications that do not require precise current adjustment. The prototype of the converter has been built. The experimental results of the current ripple are presented in the paper.
YBCO thin films in ac and dc films
Shahzada, S
2001-01-01
We report studies on the dc magnetization of YBCO thin films in simultaneously applied dc and ac fields. The effect of the ac fields is to decrease the irreversible magnetization drastically leading to complete collapse of the hysteresis loops for relatively small ac fields (250e). The magnitude of the decrease depends on the component of the ac field parallel to the c-axis. The decrease is non-linear with ac amplitude and is explained in the framework of the critical state response of ultra thin films in perpendicular geometry. The ac fields increase the relaxation rapidly at short times while the long time response appears unaffected. (author)
Ultra-high Efficiency DC-DC Converter using GaN Devices
Ramachandran, Rakesh
2016-01-01
The demands for high efficiency dc-dc power converters are increasing day by day in various applications such as telecommunication, data-centers, electric vehicles and various renewable energy systems. Silicon (Si) has been used as the semiconductor material in majority of the power devices...... properties of GaN devices can be utilized in power converters to make them more compact and highly efficient. This thesis entitled “Ultra-high Efficiency DC-DC Converter using GaN devices” focuses on achieving ultra-high conversion efficiency in an isolated dc-dc converter by the optimal utilization of Ga......N devices. Simple replacement of Si or SiC devices with GaN devices in the converter will not give an expected increase in efficiency or any improvement in the performance of the converter. The use of GaN devices has defined another dimension in the design of power converters, which mainly deals...
Isolated Bidirectional DC-DC Converter for Hybrid Electric Vehicle Application
2006-06-13
34Approved for public release: distribution is unlimited" Isolated Bidirectional DC-DC Converter for Hybrid Electric Vehicle Applications Sonya...requirements for DC-DC converters for electric and hybrid vehicles . This paper introduces a bidirectional, isolated DC-DC converter for medium power...the design and build of a medium power DC-DC converter . Key words: Power Converter , DC-DC, Hybrid Electric Vehicle , Battery, Galvanically Isolation
Efficient, lightweight dc/dc switching converter
Cuk, S.; Middlebrook, R. D.
1981-01-01
Converters have input properties of boost power stage and output properties of buck power stage, yet they perform general conversion function with high efficiency. Other features include non-pulsating input/output currents, use of capacitive energy transfer, low output voltage ripple, reduced EMI, and small size.
Power factor controller used as DC-DC converter for photovoltaic sources
Mukerjee, A.K.; Dasgupta, Nivedita [Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India)
2008-06-15
An active power factor controller (PFC) integrated circuit, normally used in AC circuits, has been used for DC-to-DC boost conversion with a stable output voltage for a variable DC input voltage as obtained from photovoltaic (PV) sources. The circuit described here uses a power factor controller MC 34262 to give approximately 400 V{sub DC} output for an input variation from 90 to 280 V{sub DC}. The maximum efficiency achieved was 98% at 450 W. Comparisons between AC and DC operations have been made. (author)
Engineering Design of the ITER AC/DC Power Supply System
Oh, B. H.; Lee, K. W.; Chang, D. S.; Jin, J. T.; Hwang, C. K.
2010-02-15
To design high power pulse power supplies, especially in huge power supplies have not designed till now, it is necessary to analyze a system's characteristics and relations with another systems as well as to know high voltage, high current control technologies. Contents of this project are; - Analysis of the changed designs of the AC/DC converters. - Setup of the PSIM model for the calculation of the junction temperature of the converter thyristors. - Finalize the converter's simulation modules and estimate the parallel number of an arm for each converter. - Fix the protection sequence and make a simulation. - Stability check of the power distribution system against the reactive power effect. - Design of small size hardware AC/DC converter. The results of these studies may used as one of references for practical designs of the power supplies and also used for developing Tokamak type fusion reactors in the future
Soft switching bidirectional DC-DC converter for ultracapacitor-batteries interface
Adib, Ehsan; Farzanehfard, Hosein [Dept. of Electrical and Computer Engineering, Isfahan Univ. of Technology (Iran)
2009-12-15
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)
Single-Phase Direct AC-AC Boost Converter
LUCANU, M.
2014-08-01
Full Text Available The paper presents a single-phase direct AC-AC boost converter. The circuit of the converter is simple and it has good performances, irrespective of the load nature. The adequate functioning and high performance of the circuit (the efficiency and waveform of the absorbed input current were tested both by simulation and experimentally.
A Novel Quasi-SEPIC High-Voltage Boost DC-DC Converter
Siwakoti, Yam Prasad; N. Soltani, Mohsen; Mostaan, Ali;
2017-01-01
This paper proposes a modified coupled-inductor SEPIC dc-dc converter for low power and high voltage gain applications such as for piezoelectric drive systems. The converter uses the same components as of SEPIC converter with an additional diode. Compared to conventional topologies with similar v...
Study of Power Flow Algorithm of AC/DC Distribution System including VSC-MTDC
Haifeng Liang
2015-08-01
Full Text Available In recent years, distributed generation and a large number of sensitive AC and DC loads have been connected to distribution networks, which introduce a series of challenges to distribution network operators (DNOs. In addition, the advantages of DC distribution networks, such as the energy conservation and emission reduction, mean that the voltage source converter based multi-terminal direct current (VSC-MTDC for AC/DC distribution systems demonstrates a great potential, hence drawing growing research interest. In this paper, considering losses of the reactor, the filter and the converter, a mathematical model of VSC-HVDC for the load flow analysis is derived. An AC/DC distribution network architecture has been built, based on which the differences in modified equations of the VSC-MTDC-based network under different control modes are analyzed. In addition, corresponding interface functions under five control modes are provided, and a back/forward iterative algorithm which is applied to power flow calculation of the AC/DC distribution system including VSC-MTDC is proposed. Finally, by calculating the power flow of the modified IEEE14 AC/DC distribution network, the efficiency and validity of the model and algorithm are evaluated. With various distributed generations connected to the network at appropriate locations, power flow results show that network losses and utilization of transmission networks are effectively reduced.
Autonomous Control of Interlinking Converter With Energy Storage in Hybrid AC–DC Microgrid
Loh, Poh Chiang; Li, Ding; Chai, Yi Kang
2013-01-01
The coexistence of ac and dc subgrids in a hybrid microgrid is likely given that modern distributed sources can either be ac or dc. Linking these subgrids is a power converter, whose topology should preferably be not too unconventional. This is to avoid unnecessary compromises to reliability......, simplicity, and industry relevance of the converter. The desired operating features of the hybrid microgrid can then be added through this interlinking converter. To demonstrate, an appropriate control scheme is now developed for controlling the interlinking converter. The objective is to keep the hybrid...... microgrid in autonomous operation with active power proportionally shared among its distributed sources. Power sharing here should depend only on the source ratings and not their placements within the hybrid microgrid. The proposed scheme can also be extended to include energy storage within...
Silicon carbide DC-DC multilevel Cuk converter
Almalaq, Yasser; Alateeq, Ayoob; Matin, Mohammad
2016-09-01
In this paper, DC-DC multilevel cuk converter using silicon carbide (SiC) Components is presented. Cuk converter gives output voltage with negative polarity. This topology is useful for applications require high gain with limitation on duty cycle. The gain of the design can be enhanced by increasing the number of multiplier level (N). This relation between the gain and the number of levels is the major advantage of this multilevel cuk converter. In the proposed cuk converter, a single SiC MOSFET, 2N-1 SiC schottky diodes, 2N capacitors, 2 inductors, and single input voltage are used to supply a load with negative polarity. 300V input voltage, 50KHz switching frequency, and 75% duty cycle are the main parameters used in the design. The output parameters are 3KW power and -5.7 KV voltage. Because this design can be used in applications which temperature plays a critical role, the relation between increasing temperature and output voltage and power are tested. The design is simulated using LTspice software and the results are discussed.
Nonlinear Phenomena and Resonant Parametric Perturbation Control in QR-ZCS Buck DC-DC Converters
Hsieh, Fei-Hu; Liu, Feng-Shao; Hsieh, Hui-Chang
The purpose of this study is to investigate the chaotic phenomena and to control in current-mode controlled quasi-resonant zero-current-switching (QR-ZCS) DC-DC buck converters, and to present control of chaos by resonant parametric perturbation control methods. First of all, MATLAB/SIMULINK is used to derive a mathematical model for QR-ZCS DC-DC buck converters, and to simulate the converters to observe the waveform of output voltages, inductance currents and phase-plane portraits from the period-doubling bifurcation to chaos by changing the load resistances. Secondly, using resonant parametric perturbation control in QR-ZCS buck DC-DC converters, the simulation results of the chaotic converter form chaos state turn into stable state period 1, and improve ripple amplitudes of converters under the chaos, to verify the validity of the proposes method.
Energy Evaluation for DC/DC Converters in DC-Based Wind Farms
Max, Lena
2007-02-15
In this thesis the suitability of three topologies for DC/DC converters in a DC wind farm grid is investigated from an energy efficiency and energy production cost point of view. The three selected topologies are the fullbridge converter, the single active bridge converter and the series parallel resonant converter. The losses are calculated for all three topologies as a function of the wind speed considering the losses in the semiconductor components and in the transformer. To obtain the average losses, the losses for each converter are integrated over the wind distribution for different average wind speeds. It is found that the resonant converter has the lowest losses of the three types for the DC wind farm application with power losses of about 2.0 - 2.5 % of the input power and the fullbridge converter has slightly higher losses with 2.3 - 3.5 % losses depending on the position in the wind turbine grid. The single active bridge converter has considerably higher losses than the other two topologies with 3.5 - 5.0 % losses. It is shown that the variable operating conditions create problems for all three converters, and as mentioned the single active bridge converter is most affected by the wide range of operation conditions. When comparing the resonant converter and the fullbridge converter, the fullbridge converter has a smaller transformer as well as lower peak current and peak voltage, but also a higher number of diode modules in the output bridge. Comparing the contribution to the energy production cost for the converters, the topology with the lowest contribution varies between the positions in the wind turbine grid. For some positions, the cost of the higher losses for the fullbridge converter are compensated by lower investment cost for the fullbridge converter compared to the resonant converter. Considering the resonant capacitor, the higher peak voltage and the variable frequency control for the resonant converter, the fullbridge converter is here found
Design of DC-DC Converter and its Control for a Wind Generation System Connected to an Isolated Load
Carlos A. Ramírez Gómez
2013-11-01
Full Text Available A method to design a Buck converter and its control, which are associated to a wind generation system that is feeding an isolated load, is presented in this paper. To design the converter a Thevenin equivalent is deduced, which represents the behavior of the wind turbine, the permanent magnet synchronous generator, and the rectifier. The design of the converter elements guarantees input/output voltages and inductor current ripples of 5 % or less. The output voltage control is developed with a proportional-integral-derivative controller and as design criteria a damping of 0,707 and cutoff frequency of 1/5 converter commutation frequency are selected. The designed controller regulates the output voltage faced load perturbations and wind speed variations.
Miller, Douglas P.
1990-06-01
Space power supply manufacturers have tried to increase power density and construct smaller, highly efficient power supplies by increasing switching frequency. Incorporation of a power MOSFET as a switching element alleviates switching loss. However, values of R sub DS(on) (drain-to-source resistance in the on-state) for MOSFET's are of such magnitude to produce greater on-state losses than an equivalent BJT operated in saturation. This research serves to introduce a design concept, pertinent to low-voltage relatively-high-current applications, that minimizes the peak current through the switching element in order to reduce average power loss. Basic waveforms produced by different PWM and resonant mode topologies were examined. Theoretical analysis reveals that a ramp-sine current waveform could cut conduction power loss by at least 18 percent over a conventional Buck switching converter. A 14V, 14W combination quasi-resonant Buck/ZCS, Quasi-Resonant Buck dc-dc converter with an unregulated input voltage of 28 V was built for simplicity to demonstrate one particular waveshaping technique. This converter represents a useful example of an actual circuit which is capable of producing the desired ramp-sine switch-current waveform. Final results confirm improvement in conduction loss enhancing existing power MOSFET technology for use in dc-dc power conversion.
A Current-Fed Isolated Bidirectional DC-DC Converter
Sun, Xiaofeng; Wu, Xiaoying; Shen, Yanfeng;
2017-01-01
This paper proposes a current-fed isolated bidirectional DC-DC converter (CF-IBDC) which has the advantages of wide input voltage range, low input current ripple, low conduction losses, and soft switching over the full operating range. Compared with conventional CF-IBDCs, the voltage spikes of th...
Hysteretic Current Controlled Zvs Dc/Dc Converter For Automobile
Cernat, M.; Scortarul, P.; Tanase, A.
2007-01-01
A novel bi-directional dc-dc converter with ZVS and interleaving for dual voltage systems in automobiles is presented. A variable frequency extended band hysteretic current control method is proposed. In comparison with classical fixed frequency current control PWM, the reverse polarity peak curr...
A Component-Reduced Zero-Voltage Switching Three-Level DC-DC Converter
Qin, Zian; Pang, Ying; Wang, Huai;
2016-01-01
The basic Zero-Voltage Switching (ZVS) three-level DC-DC converter has one clamping capacitor to realize the ZVS of the switches, and two clamping diodes to clamp the voltage of the clamping capacitor. In order to reduce the reverse recovery loss of the diode as well as its cost, this paper...... proposes to remove one of the clamping diodes in basic ZVS three-level DC-DC converter. With less components, the proposed converter can still have a stable clamping capacitor voltage, which is clamped at half of the dc link voltage. Moreover, the ZVS performance will be influenced by removing the clamping...
Multi-output DC-DC converters based on diode-clamped converters configuration
Nami, A.; Zare, F.; Ghosh, A.;
2010-01-01
for a diode-clamed inverter in the grid connection systems, where boosting low rectified output-voltage and series DC link capacitors is required. To verify the proposed topology, steady-state and dynamic analyses of a MOB converter are examined. A simple control strategy has been proposed to demonstrate...... the performance of the proposed topology for a double-output boost converter. The topology and its control strategy can easily be extended to offer multiple outputs. Simulation and experimental results are presented to show the validity of the control strategy for the proposed converter....
Zhang, Huaguang; Zhou, Jianguo; Sun, Qiuye;
2017-01-01
This paper investigates the coordinated power sharing issues of interlinked ac/dc microgrids. An appropriate control strategy is developed to control the interlinking converter (IC) to realize proportional power sharing between ac and dc microgrids. The proposed strategy mainly includes two parts...
隔离式SEPIC三电平AC-AC变换器的研究%Research of Isolated SEPIC Three-level AC - AC Converter
周振军; 李磊
2011-01-01
电力电子装置已在电力系统中得到了越来越广泛的应用,代表之一就是交流调压稳压装置.但是目前的交流调压稳压器多数采用AC-DC-AC的变换方式,这种调压稳压器不仅体积大、噪音大,而且开关管的电压应力大、输出电压波形质量低.提出了一种新型的隔离式交-交变换器,它是在sepic变换器(单端初级电感转换器)的基础上引入了推挽式变压器实现电气隔离.分析了工作原理,给出了控制策略,并通过仿真论证了变换器开关管电压应力小、输出电压波形质量高等特点.%Power electronics have been more widely used in power systems. One representative of power electronics is AC voltage regulator. But the AC - DC - AC conversion type is widely used for voltage regulator now. These AC voltage regulator not only have big bulk and high noise,but also with high power switch voltage stress and low quality of output waveform. To solve these problems)an isolated three-level AC - AC direct converter was proposed. It joined the push-pull transformer to achieve electrical isolation based on sepic AC -AC converter. Its operation principle and control strategies of the converter were investigated. By modeling and simulation,the performances of the AC - AC converter were verified, such as low switch voltage stress, high quality of output waveform and so on.
Efficiency and Regulation of Commercial Low Power DC/DC Converter Modules at Low Temperatures
Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard L.
2000-01-01
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.
Kroeger, Claus [Hochschule Aalen (Germany). Wirtschaftsingenieurwesen
2009-07-01
DC-DC-Converters are used in power electronics to adapt different voltage levels of electrical sources and sinks with respect of high efficiency. To minimize electrical losses these power electronic converters always work with switching power semiconductors. This switching principle of the converter is causing a control constraint which limits the achievable performance for the voltage control drastically. This paper presents an optimization for the control sequence in a high dynamic converter control which is based on the dead-beat control design. Thus the non-avoidable control constraint will not be violated. (orig.)
Extra-High-Voltage DC-DC Boost Converters Topology with Simple Control Strategy
K. Rajambal
2009-01-01
Full Text Available This paper presents the topology of operating DC-DC buck converter in boost mode for extra-high-voltage applications. Traditional DC-DC boost converters are used in high-voltage applications, but they are not economical due to the limited output voltage, efficiency and they require two sensors with complex control algorithm. Moreover, due to the effect of parasitic elements the output voltage and power transfer efficiency of DC-DC converters are limited. These limitations are overcome by using the voltage lift technique, opens a good way to improve the performance characteristics of DC-DC converter. The technique is applied to DC-DC converter and a simplified control algorithm in this paper. The performance of the controller is studied for both line and load disturbances. These converters perform positive DC-DC voltage increasing conversion with high power density, high efficiency, low cost in simple structure, small ripples, and wide range of control. Simulation results along theoretical analysis are provided to verify its performance.
Qin, Zian; Loh, Poh Chiang; Blaabjerg, Frede
2016-01-01
various topologies have since been proposed. The intention of this paper is, thus, to study two promising single-phase ac-dc-ac converters using reduced number of switches, and subsequently proposes modulation schemes for them. The proposed schemes help the converters to achieve better thermal spread...... among their switches, while keeping their dc-link voltages low. Single points of failure are thus minimized, allowing the converters to have longer lifetimes. Simulation and experimental results have demonstrated the intended performances, hence verifying the analyses presented in this paper....
Quasi-Y-Source Boost DC–DC Converter
Siwakoti, Yam Prasad; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
In this letter, a new topology called “quasi-Y-source dc-dc converter” is presented. It inherits all the advantages of the original Y-source converter. In addition, the new topology draws a continuous current from the source, which is definitely more appropriate for most renewable sources. It als...... has dc-current-blocking capacitors, which will definitely help to prevent the coupled inductor core from saturation. Experimental testing has proven the validity of the proposed network and its application as a high boost dc-dc converter....
Novel family of quasi-Z-source DC/DC converters derived from current-fed push-pull converters
Chub, Andrii; Husev, Oleksandr; Vinnikov, Dmitri
2014-01-01
This paper is devoted to the step-up quasi-Z-source dc/dc push-pull converter family. The topologies in the family are derived from the isolated boost converter family by replacing input inductors with the quasi-Z-source network. Two new topologies are proposed, analyzed and compared. Theoretical...
Autonomous Operation of Hybrid Microgrid with AC and DC Sub-Grids
Loh, Poh Chiang; Blaabjerg, Frede
2011-01-01
This paper investigates on the active and reactive power sharing of an autonomous hybrid microgrid. Unlike existing microgrids which are purely ac, the hybrid microgrid studied here comprises dc and ac sub-grids, interconnected by power electronic interfaces. The main challenge here is to manage...... the power flow among all the sources distributed throughout the two types of sub-grids, which certainly is tougher than previous efforts developed for only either ac or dc microgrid. This wider scope of control has not yet been investigated, and would certainly rely on the coordinated operation of dc...... sources, ac sources and interlinking converters. Suitable control and normalization schemes are therefore developed for controlling them with results presented for showing the overall performance of the hybrid microgrid....
Custom DC-DC converters for distributing power in SLHC trackers
Allongue, B; Blanchot, G; Faccio, F; Fuentes, C; Mattavelli, P; Michelis, S; Orlandis, S; Spiazzi, G
2008-01-01
A power distribution scheme based on the use of on-board DC-DC converters is proposed to efficiently distribute power to the on-detector electronics of SLHC trackers. A comparative analysis of different promising converter topologies is presented, leading to the choice of a magneticbased buck converter as a first conversion stage followed by an on-chip switched capacitors converter. An overall efficiency above 80% is estimated for the practical implementation proposed.
Modeling and Analysis of Transformerless High Gain Buck-boost DC-DC Converters
Vu Tran
2014-12-01
Full Text Available This paper proposes a transfomerless switched capacitor buck boost converter model, which provides higher voltage gain and higher efficiency when compared to the conventional buck boost converter. The averaged model based on state-space description is analyzed in the paper. The simulation results are presented to confirm the capability of the converter to generate high voltage ratios. The comparison between the proposed model and the traditional model is also provided to reveal the improvement. The proposed converter is suitable for for a wide application which requires high step-up DC-DC converters such as DC micro-grids and solar electrical energy.
Test Results of Selected Commercial DC/DC Converters under Cryogenic Temperatures - A Digest
Patterson, Richard; Hammoud, Ahmad
2010-01-01
DC/DC converters are widely used in space power systems in the areas of power management and distribution, signal conditioning, and motor control. Design of DC/DC converters to survive cryogenic temperatures will improve the power system performance, simplify design, and reduce development and launch costs. In this work, the performance of nine COTS modular, low-tomedium power DC/DC converters was investigated under cryogenic temperatures. The converters were evaluated in terms of their output regulation, efficiency, and input and output currents. At a given temperature, these properties were obtained at various input voltages and at different load levels. A summary on the performance of the tested converters was given. More comprehensive testing and in-depth analysis of performance under long-term exposure to extreme temperatures are deemed necessary to establish the suitability of these and other devices for use in the harsh environment of space exploration missions.
Study on the Control Algorithm of Two-Stage DC-DC Converter for Electric Vehicles
Changhao Piao
2014-01-01
Full Text Available The fast response, high efficiency, and good reliability are very important characteristics to electric vehicles (EVs dc/dc converters. Two-stage dc-dc converter is a kind of dc-dc topologies that can offer those characteristics to EVs. Presently, nonlinear control is an active area of research in the field of the control algorithm of dc-dc converters. However, very few papers research on two-stage converter for EVs. In this paper, a fixed switching frequency sliding mode (FSFSM controller and double-integral sliding mode (DISM controller for two-stage dc-dc converter are proposed. And a conventional linear control (lag is chosen as the comparison. The performances of the proposed FSFSM controller are compared with those obtained by the lag controller. In consequence, the satisfactory simulation and experiment results show that the FSFSM controller is capable of offering good large-signal operations with fast dynamical responses to the converter. At last, some other simulation results are presented to prove that the DISM controller is a promising method for the converter to eliminate the steady-state error.
SIMPLIFIED APPROACHES FOR CONTROLLING DC-DC POWER CONVERTERS
M. M. ABDEL AZIZ
2012-02-01
Full Text Available This paper represents the design procedures of different compensation schemes for voltage mode controlled (VMC dc–dc switching converters. Proportional integral derivative (PID controllers, Fuzzy logic controllers (FLC, parallel combination of PID and FLC, and FLC tuned by PI controller have been investigated. MATLAB software is used to depict the buck converter performance with each compensator type when it is electrically simulated, and analytically modeled using its equivalent transfer function (TF. The comparative study Resultsemphasize that FLC tuned by PI controller is superior to the other control strategies because of fast transient response, minimum steady state error and good disturbance rejection under various variations of the operating conditions. Hence, it achieves the most tightly output voltage regulation.
Efficient and ripple-mitigating dc-dc converter for residential fuel cell system
Wang, Yong [Danfoss Solar Inverters, Hardware, Jyllandsgade 28, 6400 Soenderborg (Denmark); Choi, Seeyoung [Digital Appliance Division, Samsung Electronics Co. Ltd., Maetan-3Dong, Suwon, Gyeonggi (Korea); Lee, Eunchul [Willings Co. Ltd., SK Ventium, 522 Dangjung-Dong, Gunpo-Si, Gyeonggi-Do (Korea)
2009-01-15
Proton exchange membrane fuel cell (PEMFC) systems for residential application require efficient and ripple-mitigating power conditioning system (PCS). The key point to reach it, is the design and control of the dc-dc converter. Based on the theoretical and experimental analysis of the traditional converter, this paper proposes a novel parallel-series full bridge (P-SFB) dc-dc converter, and improves its phase shifting scheme. This paper also proposes a novel controller for low frequency ripple current suppressing applied on the converter. The experimental results verify that, the dc-dc converter achieves a peak efficiency of 95.5%. Therefore PCS's maximum efficiency reaches 92.9%. And the input current ripple is reduced significantly with the new controller. (author)
AC/DC Smart Control And Power Sharing of DC Distribution Systems
2012-02-10
21 conditions such that the output voltage is constant. Duty cycle is varied using a pulse width modulation (PWM) technique. PID controllers are...19 CHAPTER 3 SMART CONTROL OF DC-DC BOOST CONVERTER IN PV SYSTEMS 3.1 Problem Statement Proportional integral derivative ( PID ... controllers are usually used to control DC- DC boost converters in photovoltaic (PV) systems. However, they have to be tuned based on certain defined
DC Smart Grid Connected with Fuel Charging Station and AC Load by Hybrid MLI
Naveen Kumar
2013-07-01
Full Text Available This paper presents the Solar (photo voltaic power Plant and Windmill plant with DC Smart Grid connected with an DC Fuel Charging Station For Electric Vehicle (EV, Plug in Hybrid Electric Vehicle (PHEV and converted to AC load for Consumer single or Three phase ac load by means of Hybrid Multilevel Inverter (MLI. Solar Energy which store energy in lithium-ion battery and connected to Smart Grid .Wind Energy which get stored in Lithium-ion battery that Fixed DC Voltage connected with DC Smart Grid. Smart Grid which are Connected with DC Fuel Charging Station in Ring Topology with a certain distance for charging of Electric Vehicle (EV and Plug-in Hybrid Electric Vehicle with On-Board (Integrated Charger for faster charging of EV. In Power demand for Consumer the DC load from smart grid converted into an ac load by Hybrid Multilevel Inverter. In Consumers Place the small wind mill and PV panel are installed that energy can be used for consumers load at peak time or power Shutdown .Other than the power shutdown or peak time in the consumers place, stored DC Energy can be fed to Smart Grid. A major development in distribution automation is deployment of smart meters as a gateway between the utility and customer. With such capabilities the smart meter becomes not only a point of measurement of consumed kWh but also a controller capable of bidirectional communications with both the customer and utility.
张扬; 查晓明; 刘雅琦; 张鲲; 熊一; 樊友平
2012-01-01
This paper deals with the issue of modeling method by perturbation solution to the single-phase AC-DC converter. A continuous circuit that includes a single-phase AC-DC converter is inducted first. And then a differential equation is presented with two parameters, which are controlling parameter and small perturbation parameter. A strict proof indicates that this equation can be solved by the regular perturbation. The compareison between the result and the simulation figures of PSCAD/EMTDC, shows that the result is correct and simple, thus avoiding the requirements for large computation capacity. Finally, the physical significance of the two parameters is analyzed, showing that they may incur the period-doubling chaos. This method not only fits the single-phase AC-DC converter circuit, but also meets the need of two-phase or N-phase circuits.%针对单相交直流全桥变流电路，推导出其在脉宽调制下的连续等效摄动解析模型．首先通过研究非线性振荡过程得到其连续微分方程，该方程含有控制参数和摄动参数．随后通过数学理论证明正则摄动方法能够求出其近似解，求解后对比PSCAD／EMTDC的仿真结果从而验证了解析的正确性．该方法在大规模计算中具有优势．最后分析了控制参数和摄动参数的物理意义，指出这两个参数能够影响变流器的工作状态，甚至引发倍周期混沌．该摄动建模方法不仅适用于单相变流电路，也适用于三相变流电路甚至多相变流电路．
Five-Level Active-Neutral-Point-Clamped DC/DC Converter for Medium-Voltage DC Grids
Liu, Dong; Deng, Fujin; Chen, Zhe
2017-01-01
effectively eliminate high voltage leaps caused by the dead time effect. In addition, a capacitor voltage control strategy is proposed for the 5L-ANPC dc/dc converter to ensure the balanced flying capacitor voltage and desired five-level voltage waveforms. Finally, simulation and experimental studies......This paper proposes a five-level active-neutralpoint- clamped (5L-ANPC) dc/dc converter for applications in medium voltage dc (MVDC) grids. A modulation strategy is proposed for the 5L-ANPC dc/dc converter to generate multilevel voltage waveforms, which can effectively reduce voltage change rate dv...... are conducted, and the results have verified the proposed converter and control strategies....
Single Event Burnout in DC-DC Converters for the LHC Experiments
Claudio H. Rivetta et al.
2001-09-24
High voltage transistors in DC-DC converters are prone to catastrophic Single Event Burnout in the LHC radiation environment. This paper presents a systematic methodology to analyze single event effects sensitivity in converters and proposes solutions based on de-rating input voltage and output current or voltage.
Robust DC/DC converter control for polymer electrolyte membrane fuel cell application
Wang, Ya-Xiong; Yu, Duck-Hyun; Chen, Shi-An; Kim, Young-Bae
2014-09-01
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.
High power density dc/dc converter: Component selection and design
Divan, Deepakraj M.
1989-01-01
Further work pertaining to design considerations for the new high power, high frequency dc/dc converters is discussed. The goal of the project is the development of high power, high power density dc/dc converters at power levels in the multi-kilowatt to megawatt range for aerospace applications. The prototype converter is rated for 50 kW at a switching frequency of 50 kHz, with an input voltage of 200 Vdc and an output of 2000 Vdc. The overall power density must be in the vicinity of 0.2 to 0.3 kg/kW.
Dynamic Performance of Grid Converters using Adaptive DC Voltage Control
Trintis, Ionut; Sun, Bo; Guerrero, Josep M.;
2014-01-01
This paper investigates a controller that ensures minimum operating dc-link voltage of a back-to-back converter system. The dc-link voltage adapts its reference based on the system state, reference given by an outer loop to the dc-link voltage controller. The operating dc-link voltage should...... be kept as low as possible to increase the power conversion efficiency and increase the reliability of converters. The dynamic performance of the proposed controller is investigated by simulations and experiments....
Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.
2012-01-01
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…
Pelan, Ovidiu; Cornea, Octavian; Muntean, Nicolae
2014-01-01
This paper presents and discusses design considerations and efficiency investigation of a conventional step-down and a hybrid switched-capacitor DC-DC converter. Three MOSFETs with low on-resistance have been tested for each converter in order to find the most adequate switch for this application...
A Bidirectional Multi-Port DC-DC Converter Integrating Voltage Equalizer
Chen, Jianfei; Hou, Shiying; Deng, Fujin
2015-01-01
with a uniform voltage level while eliminating the voltage imbalance. In addition, high step-down and step-up ratios with low component voltage stress can be achieved in the proposed converter. A bidirectional four-port dc-dc converter is presented to do theoretical analysis for the voltage equalization of three...
Model predictive control of bidirectional isolated DC-DC converter for energy conversion system
Akter, Parvez; Uddin, Muslem; Mekhilef, Saad; Tan, Nadia Mei Lin; Akagi, Hirofumi
2015-08-01
Model predictive control (MPC) is a powerful and emerging control algorithm in the field of power converters and energy conversion systems. This paper proposes a model predictive algorithm to control the power flow between the high-voltage and low-voltage DC buses of a bidirectional isolated full-bridge DC-DC converter. The predictive control algorithm utilises the discrete nature of the power converters and predicts the future nature of the system, which are compared with the references to calculate the cost function. The switching state that minimises the cost function is selected for firing the converter in the next sampling time period. The proposed MPC bidirectional DC-DC converter is simulated with MATLAB/Simulink and further verified with a 2.5 kW experimental configuration. Both the simulation and experimental results confirm that the proposed MPC algorithm of the DC-DC converter reduces reactive power by avoiding the phase shift between primary and secondary sides of the high-frequency transformer and allow power transfer with unity power factor. Finally, an efficiency comparison is performed between the MPC and dual-phase-shift-based pulse-width modulation controlled DC-DC converter which ensures the effectiveness of the MPC controller.
Eka Prasetyono
2015-09-01
Full Text Available Bidirectional DC-DC converter is needed in the energy storage system. The converter topology used in this paper was a non-isolated bidirectional DC-DC buck-boost converter. This converter worked in two ways, which the charging mode stored energy into battery when load current was less than nominal main DC current (set point and discharging mode transferred energy from battery to the load when its current exceeded set point value. Both of these modes worked automatically according to the load current. The charging and discharging currents were controlled by fuzzy logic controller which was implemented on microcontroller ARM Cortex-M4F STM32F407VG. This paper compares two types of fuzzy membership function (triangular and sigmoid in controlling bidirectional DC-DC converter. The results showed that fuzzy logic controller with triangle membership function and sigmoid as control bidirectional DC-DC converter had no significant different response, both had an average error for charging and discharging process under 4% with ripple current on the main DC bus around 0.5%. The computing time of program for fuzzy logic controller with triangular membership functions had 19.01% faster than sigmoid, and fuzzy logic computation time on a microcontroller with hardware floating point was 60% faster than software floating point.
Adell, Philippe
When electronic devices are used in space and military systems, they may be exposed to various types of radiation, including photons, electrons, protons, neutrons, and heavy ions. The effects of radiation on the semiconductor devices within the systems range from gradual degradation to catastrophic failure. In order to design and produce reliable systems for space or military applications, it is necessary to understand the device-level effects of radiation and develop appropriate strategies for reducing system susceptibility. This research focuses on understanding radiation effects in power converters for space and military applications. We show that power converters are very sensitive to radiation (total-dose, single event effects and displacement damage) and that their radiation response is dependent on input bias conditions and load conditions. We compared the radiation hardness of various power converter topologies using experiments and simulations. Evaluation of these designs under different modes of operation is demonstrated to be critical for determining radiation hardness. We emphasize the correlation between radiation effects and the role of the dynamic response of these topologies. For instance, total dose exposure has been found to degrade loop gain and affect regulation in some converters. We propose several radiation-hardening solutions to improve the radiation response of these designs. For instance, we demonstrate the design of a digitally controlled boost converter suitable for space applications based on an SRAM FPGA. A design hardening solution has been developed and successfully applied through VHDL simulations and experiments to assure the continuous operation of the converter in the presence of SEES (more precisely SEFIs). This research led to the design of a digitally controlled radiation hardened integrated switching buck converter. The proposed design is suitable for micro-satellite applications and is based on a high-voltage/CMOS process
Natsheh, Ammar N. [Faculty of Engineering, Al-Ahliyya Amman University, Post Code 19328 Amman (Jordan); Nazzal, Jamal M. [Faculty of Engineering, Al-Ahliyya Amman University, Post Code 19328 Amman (Jordan)]. E-mail: jnazzal@ammanu.edu.jo
2007-08-15
This work describes the bifurcational behavior of a modular peak current-mode controlled DC-DC boost converter with multi bifurcation parameters. The parallel-input/parallel-output converter consists of two identical boost circuits and operates in the continuous-current conduction mode (CCM). A nonlinear mapping in closed form is derived and bifurcation diagrams are generated using MATLAB. A comparison is made between the modular converter diagrams with those of the single boost converter. The effect of introducing mutual coupling between the inductors of the constituent modules is also addressed. Results are verified using the circuit analysis package PSPICE.
Soliman, Hammam Abdelaal Hammam; Wang, Huai; Blaabjerg, Frede
2016-01-01
of the aforementioned challenges and shortcomings. In this paper, a pure software condition monitoring method based on Artificial Neural Network (ANN) algorithm is proposed. The implemented ANN estimates the capacitance of the dc-link capacitor in a back-to-back converter. The error analysis of the estimated results...... is also studied. The developed ANN algorithm has been implemented in a Digital Signal Processor (DSP) in order to have a proof of concept of the proposed method....
Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1
Lee, F. C.; Mahmoud, M. F.; Yu, Y.
1980-01-01
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.
DC-DC converters with reduced mass for trackers at the HL-LHC
Affolder, A.; Allongue, B.; Blanchot, G.; Faccio, F.; Fuentes, C.; Greenall, A.; Michelis, S.
2011-11-01
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.
Kim, Ho-sung [Department of Electrical Engineering, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea); New and Renewable Energy System Research Center, Korea Electro-technology Research Institute, 28-1, Sungju-dong Changwon-si, Kyungsannam-do, 641-120 (Korea); Kim, Jong-Hyun; Min, Byung-Duk; Yoo, Dong-Wook [New and Renewable Energy System Research Center, Korea Electro-technology Research Institute, 28-1, Sungju-dong Changwon-si, Kyungsannam-do, 641-120 (Korea); Kim, Hee-Je [Department of Electrical Engineering, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea)
2009-11-15
A photovoltaic (PV) power conditioning system (PCS) must have high conversion efficiency and low cost. Generally, a PV PCS uses either a single string converter or a multilevel module integrated converter (MIC). Each of these approaches has both advantages and disadvantages. For a high conversion efficiency and low cost PV module, a series connection of a module integrated DC-DC converter output with a photovoltaic panel was proposed. The output voltage of the PV panel is connected to the output capacitor of the fly-back converter. Thus, the converter output voltage is added to the output voltage of the PV panel. The isolated DC-DC converter generates only the difference voltage between the PV panel voltage and the required total output voltage. This method reduces the power level of the DC-DC converter and enhances energy conversion efficiency compared with a conventional DC-DC converter. (author)
A Reduced-Part, Triple-Voltage DC-DC Converter for Electric Vehicle Power Management
Su, Gui-Jia [ORNL; Tang, Lixin [ORNL
2007-01-01
Electrical power systems in future hybrid and fuel cell vehicles may consist of three voltage nets; 14 V, 42 V and high voltage (>200 V) buses. A soft-switched, bi-directional dc-dc converter using only four switches was proposed for interconnecting the three nets. This paper presents a reduced- part dc-dc converter, which decreases the converter cost while retaining all the favorable features of the original topology. Simulation and experimental data are included to verify a simple power flow control scheme.
Critical conditions of saddle-node bifurcations in switching DC-DC converters
Fang, Chung-Chieh
2013-08-01
Although existence of multiple periodic orbits in some DC-DC converters have been known for decades, linking the multiple periodic orbits with the saddle-node bifurcation (SNB) is rarely reported. The SNB occurs in popular DC-DC converters, but it is generally reported as a strange instability. Recently, design-oriented instability critical conditions are of great interest. In this article, average, sampled-data and harmonic balance analyses are applied and they lead to equivalent results. Many new critical conditions are derived. They facilitate future research on the instability associated with multiple periodic orbits, sudden voltage jumps or disappearances of periodic orbits observed in DC-DC converters. The effects of various converter parameters on the instability can be readily seen from the derived critical conditions. New Nyquist-like plots are also proposed to predict or prevent the occurrence of the instability.
Zhan, Yihong; Cao, Zhenning; Bao, Ning; Li, Jianbo; Wang, Jun; Geng, Tao; Lin, Hao; Lu, Chang
2012-06-28
Conventional electroporation has been conducted by employing short direct current (dc) pulses for delivery of macromolecules such as DNA into cells. The use of alternating current (ac) field for electroporation has mostly been explored in the frequency range of 10kHz-1MHz. Based on Schwan equation, it was thought that with low ac frequencies (10Hz-10kHz), the transmembrane potential does not vary with the frequency. In this report, we utilized a flow-through electroporation technique that employed continuous 10Hz-10kHz ac field (based on either sine waves or square waves) for electroporation of cells with defined duration and intensity. Our results reveal that electropermeabilization becomes weaker with increased frequency in this range. In contrast, transfection efficiency with DNA reaches its maximum at medium frequencies (100-1000Hz) in the range. We postulate that the relationship between the transfection efficiency and the ac frequency is determined by combined effects from electrophoretic movement of DNA in the ac field, dependence of the DNA/membrane interaction on the ac frequency, and variation of transfection under different electropermeabilization intensities. The fact that ac electroporation in this frequency range yields high efficiency for transfection (up to ~71% for Chinese hamster ovary cells) and permeabilization suggests its potential for gene delivery.
Zhang, Huaguang; Zhou, Jianguo; Sun, Qiuye; Guerrero, Josep M.; Ma, Dazhong
2016-01-01
This paper investigates the coordinated power sharing issues of interlinked ac/dc microgrids. An appropriate control strategy is developed to control the interlinking converter (IC) to realize proportional power sharing between ac and dc microgrids. The proposed strategy mainly includes two parts: the primary outer-loop dual-droop control method along with secondary control; the inner-loop data-driven model-free adaptive voltage control. Using the proposed scheme, the interlinking converter, ...
Voltage Tracking of a DC-DC Flyback Converter Using Neural Network Control
Wahyu Mulyo Utomo
2012-01-01
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.
Characterization of diode valve in medium voltage dc/dc converter for wind turbines
Dincan, Catalin Gabriel; Kjær, Philip Carne
2016-01-01
This paper proposes a methodology for characterization of medium voltage (MV), medium frequency (MF) rectifier diode valve. The intended application is for 10MW dc/dc converters used in DC offshore wind turbines. Sensitivity to semiconductor component parameter variation, snubber component...
Novel bidirectional DC-DC converters based on the three-state switching cell
da Silva Júnior, José Carlos; Robles Balestero, Juan Paulo; Lessa Tofoli, Fernando
2016-05-01
It is well known that there is an increasing demand for bidirectional DC-DC converters for applications that range from renewable energy sources to electric vehicles. Within this context, this work proposes novel DC-DC converter topologies that use the three-state switching cell (3SSC), whose well-known advantages over conventional existing structures are ability to operate at high current levels, while current sharing is maintained by a high frequency transformer; reduction of cost and dimensions of magnetics; improved distribution of losses, with consequent increase of global efficiency and reduction of cost associated to the need of semiconductors with lower current ratings. Three distinct topologies can be derived from the 3SSC: one DC-DC converter with reversible current characteristic able to operate in the first and second quadrants; one DC-DC converter with reversible voltage characteristic able to operate in the first and third quadrants and one DC-DC converter with reversible current and voltage characteristics able to operate in four quadrants. Only the topology with bidirectional current characteristic is analysed in detail in terms of the operating stages in both nonoverlapping and overlapping modes, while the design procedure of the power stage elements is obtained. In order to validate the theoretical assumptions, an experimental prototype is also implemented, so that relevant issues can be properly discussed.
Reliability-Oriented Optimization for the LC Filter Design of a Buck DC-DC Converter
Liu, Yi; Huang, Meng; Wang, Huai;
2017-01-01
Lifetime is an important performance factor in the reliable operation of power converters. However, the state-of-the-art LC filter design of a buck DC-DC converter is limited to the specifications of voltage and current ripples and constrains in power density and cost without reliability...... parameter sets. A 1 kW converter prototype is applied to verify the theoretical analysis and simulation....
Push-pull with recovery stage high-voltage DC converter for PV solar generator
Nguyen, The Vinh; Aillerie, Michel; Petit, Pierre; Pham, Hong Thang; Vo, Thành Vinh
2017-02-01
A lot of systems are basically developed on DC-DC or DC-AC converters including electronic switches such as MOS or bipolar transistors. The limits of efficiency are quickly reached when high output voltages and high input currents are needed. This work presents a new high-efficiency-high-step-up based on push-pull DC-DC converter integrating recovery stages dedicated to smart HVDC distributed architecture in PV solar energy production systems. Appropriate duty cycle ratio assumes that the recovery stage work with parallel charge and discharge to achieve high step-up voltage gain. Besides, the voltage stress on the main switch is reduced with a passive clamp circuit and thus, low on-state resistance Rdson of the main switch can be adopted to reduce conduction losses. Thus, the efficiency of a basic DC-HVDC converter dedicated to renewable energy production can be further improved with such topology. A prototype converter is developed, and experimentally tested for validation.
Comparison of soft and hard-switching effiency in a three-level single phase 60kW dc-ac converter
Munk-Nielsen, Stig; Teodorescu, Remus; Bech, Michael Møller;
2003-01-01
Efficiency measurements on a three-level single-phase soft-switched converter are presented and show a slightly improved efficiency compared with the hard-switched converter for output powers higher than 25 % of rated power. The resonant converter switches are Zero Voltage Switched (ZVS) and a si......Efficiency measurements on a three-level single-phase soft-switched converter are presented and show a slightly improved efficiency compared with the hard-switched converter for output powers higher than 25 % of rated power. The resonant converter switches are Zero Voltage Switched (ZVS...
1V.Chaitanya,P.G.scholar,
2015-10-01
Full Text Available : Even though electrical vehicle concept is introduced in early 1800’s, it gained importance in past couple of decades due to growing conscience on environmental aspects. Different types of electrical vehicles are manufactured in the past centuries and now onboard generation is seems to be promising by fulfilling the needs of a vehicle. Fuel cells or fuel cell stack produces typically 32-68V of EMF, which has to be conditioned before it fed to motor. The conditioning involves two stages DCDC conversion and then to DC-AC conversion .DC-AC conversion is done through inverter. For DC-DC to conversion various topologies are proposed such as fly back, forward, buck-boost are proposed. This paper deals with the front end DC-DC converter and inverter switching. A hybrid modulation scheme is used to produce pulses to switch the source end full bridge rectifier and inverter at load end. In this modulation scheme high frequency pulses given to full bridge rectifier and 33% modulation scheme based pulses are produced for inverter switching.
管乐诗; 王懿杰; 王卫; 张相军; 徐殿国
2016-01-01
A single-stage AC-DC converter based on the boundary conduction mode( BCM )boost circuit and the LLC resonant circuit is proposed in the paper. The input voltage is divided into two parts,each of which forms a BCM boost circuit by sharing one switch of the LLC resonant circuit. Because of the integration,the proposed AC-DC converter is with less components and low cost. At the same time,the boost circuit works in the BCM mode so that the power factor correction function is realized. The integration of the switches does not affect the soft-switching characteristics of the half bridge LLC resonant circuit,so that the converter switching losses is decreased and the converter efficiency is increased. A 100 W prototype is built to prove the analysis,the power factor(PF)is 0. 975,the total harmonic distortion(THD)is 21. 5% satisfying the IEC 63000—3—2 standard, and its efficiency is 90. 8%.%提出一种基于临界模式Boost电路与LLC谐振电路的单级交直变换器，由于其通过输入分压与LLC谐振电路的两个开关管各形成一个临界模式的Boost电路，实现了开关管的集成，降低了系统成本。同时Boost电路工作在临界模式，实现了功率因数校正作用，开关管的集成并没有改变LLC半桥谐振电路的软开关特性，降低了变换器中开关元件的损耗，在一定程度上提高了变换器效率。通过一100 W实验样机的实验验证可知，系统满载时功率因数高达0.975，总谐波失真（ THD）为21.5豫并满足IEC 63000—3—2的标准，效率为90.8豫。
AC Loss of Ripple Current in Superconducting DC Power Transmission Cable
Yoshitomi, K.; Otabe, E. S.; Vyatkin, V. S.; Kiuchi, M.; Matsushita, T.; Hamabe, M.; Yamaguchi, S.; Inada, R.
As a method of largely reducing the transmission loss in the electric power grid, superconducting direct current (DC) power transmission cable has been investigated. Using superconducting DC power transmission cables, large amounts of current and energy can be transferred compared to conventional copper cables. In this case, an alternating current (AC) is converted to DC and superposed AC which is known as ripple current, and the energy loss by the ripple current is generated. Therefore it is desired to estimate the energy loss density for the case of DC current and superposed AC current for a design of DC transmission cable system. In this study, the hysteresis loss for DC current of 2 kA rectified from 60 Hz alternating current is calculated using the Bean model, and coupling loss was also estimated. The diameter of the cable was 40 mm. The ripple currents generated by multi-pulse rectifiers, 6-pulse, 12-pulse, and 24-pulse were considered. It is found that the total AC loss including the hysteresis loss and the coupling loss is considerably smaller than the supposed heat loss of 0.5 W/m which is obtained with a newly developed cable.
Sugimura, Hisayuki; Muraoka, Hidekazu; Hiraki, Eiji; Hirota, Izuo; Yasui, Kenji; Omori, Hideki; Lee, Hyun-Woo; Nakaoka, Mutsuo
In this paper, high frequency power converter without DC smoothing electrolytic capacitor filter link which convert the 100V/200Vrms and 60Hz single phase utility frequency AC power into a high frequency AC. This proposed high frequency AC power converter without electrolytic capacitor filter can operate under a principle of soft switching PWM based on a lossless capacitor snubber is proposed and demonstrated for consumer high frequency induction heating (IH). In particular, this high frequency power converter capable of producing a high frequency AC more than 20kHz is developed for consumer IH applications as hot water producer and steamer based on the specially designed spiral type IH-Dual Packs Heater (DPH), which includes the dual mode pulse modulation control scheme based on soft switching PWM for high output power setting and commercial frequency AC zero voltage soft switching pulse density modulation (PDM) for low output power settings. This developed high frequency power frequency converter using trench gate IGBTs is clarified on the basis of experimental and simulation results for its circuit operation of the utility frequency AC to high frequency AC frequency PWM power converter without the electrolytic capacitor bank DC filter link for the IH hot water and IH steamer. These IH appliances are based upon an innovative electromagnetic IH-DPH for fluid heating as heat exchanger in consumer pipeline. Finally, its power regulation characteristics, power conversion efficiency and harmonic current components characteristics including power factor in utility AC grid side are evaluated and discussed from an experimental point of view. The practical effectiveness of this utility frequency AC to high frequency AC soft switching high power frequency converter defined conveniently as high frequency soft switching cyclo-inverter is proved as one of the important products effective for next generation IH application all electricity power utilizations.
Advanced DC/DC Converters Towards Higher Volumetric Efficiencies For Space Applications
Shaw, Harry; Shue, Jack; Liu, David; Wang, Bright; Plante, Jeanette
2005-01-01
A new emphasis on planetary exploration by NASA drives the need for small, high power DC/DC converters which are functionally modular. NASA GSFC and other government space organizations are supporting technology development in the DC/DC converter area to both meet new needs and to promote more sources of supply. New technologies which enable miniaturization such as embedded passive technologies and thermal management using high thermal conductivity materials are features of the new designs. Construction of some simple DC/DC converter core circuits using embedded components was found to be successful for increasing volumetric efficiency to 37 W/inch. The embedded passives were also able to perform satisfactorily in this application in cryogenic temperatures.
imulation Results of Single Stage AC- AC Converter for Induction Heating
S. ARUMUGAM
2010-12-01
Full Text Available This paper presents simulation of single stage Induction heating system with series Load Resonance. Low frequency AC is converted in to High Frequency Ac using newly developed ZVS-PWM high frequency inverter. This High Frequency is used for Induction Heating .Single stage AC-AC converter system is modeled and simulated using Matlab Simulink. The simulation results of ZVS-PWM high frequency system are presented. The effectiveness of this UFAC-to-HFAC direct power frequency converter using IGBTs for consumer high-frequency IH appliances is evaluated and proved on the basis of simulation results.
A suitable model plant for control of the set fuel cell-DC/DC converter
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
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)
Chaudhary, Sanjay; Guerrero, Josep M.; Teodorescu, Remus
2015-01-01
The development of distributed generation system and electric vehicles is bound to strain the distribution network. A typical radial distribution feeder suffers from the voltage fluctuation and feeder overload in the presence of a large amount of variable renewable generation. This paper presents...... a concept of enhancing the power handling capacity of distribution networks using dc grid interconnections. Control of both the active and reactive power exchange between the ac feeder and the interconnecting power converter has been proposed for the voltage regulation at the ac feeder terminal. Besides...
Qin, Zian; Wang, Huai; Blaabjerg, Frede
2014-01-01
Three-phase back-to-back converters have a wide range of applications (e.g. wind turbines) in which the reliability and cost-effectiveness are of great concern. Among other components and interconnections, DC-link capacitors are one of the weak links influenced by environmental stresses (e.......g. ambient temperature, humidity, etc.) and operating stresses (e.g. voltage, ripple current). This paper serves to investigate the ways of reducing ripple current stresses of DC-link capacitors in back-toback converters. The outcome could benefit to achieve either an extended lifetime for a designed DC...
Optimized photovoltaic generator-water electrolyser coupling through a controlled DC-DC converter
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
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)
Modelling and Simulation of Digital Compensation Technique for dc-dc Converter by Pole Placement
Shenbagalakshmi, R.; Sree Renga Raja, T.
2015-09-01
A thorough and effective analysis of the dc-dc converters is carried out in order to achieve the system stability and to improve the dynamic performance. A small signal modelling based on state space averaging technique for dc-dc converters is carried out. A digital state feedback gain matrix is derived by pole placement technique in order to achieve the stability of a completely controllable system. A prediction observer for the dc-dc converters is designed and a dynamic compensation (observer plus control law) is provided using separation principle. The output is very much improved with zero output voltage ripples, zero peak overshoot, and much lesser settling time in the range of ms and with higher overall efficiency (>90 %).
Modeling and Design of Five Level Cascaded H-Bridge Multilevel Inverter with DC/DC Boost Converter
Vinayaka B.C
2014-06-01
Full Text Available Power electronic converters, especially DC/AC Sinusoidal Pulse Width Modulation inverters have been extending their range of use in industry because of their numerous advantages. They typically synthesize the stair –case voltage waveform (from several dc sources which has reduced harmonic content. This paper aims to extend the knowledge about the performance of Five level Cascaded H-Bridge MLI topology with DC/DC Boost Converter using SPWM for fixed DC Source. The output voltage is the sum of the voltage that is generated by each bridge. The switching angles can be chosen in such a way that the total harmonic distortion is minimized. This topology incorporates Boost Converter in the input side which magnifies the fundamental output voltage with reduction in total harmonic distortion. It also incorporates LC filter and hence output is drawn near the sine wave because of more levels. Results of experiments proved efficiency of 95%.The performance of the proposed SPWM strategy in terms of output voltage and THD has studied successfully and shown using MATLAB/Simulink.
A New Sliding Mode Controller for DC/DC Converters in Photovoltaic Systems
M. Sarvi
2013-01-01
Full Text Available DC/DC converters are widely used in many industrial and electrical systems. As DC/DC converters are nonlinear and time-variant systems, the application of linear control techniques for the control of these converters is not suitable. In this paper, a new sliding mode controller is proposed as the indirect control method and compared to a simple direct control method in order to control a buck converter in photovoltaic applications. The solar arrays are dependent power sources with nonlinear voltage-current characteristics under different environmental conditions (insolation and temperature. From this point of view, the DC/DC converter is particularly suitable for the application of the sliding mode control in photovoltaic application, because of its controllable states. Simulations are performed in Matlab/Simulink software. The simulation results are presented for a step change in reference voltage and input voltage as well as step load variations. The simulations results of proposed method are compared with the conventional PID controller. The results show the good performance of the proposed sliding mode controller. The proposed method can be used for the other DC/DC converter.
DC-DC power converter research for Orbiter/Station power exchange
Ehsani, M.
1993-01-01
This project was to produce innovative DC-DC power converter concepts which are appropriate for the power exchange between the Orbiter and the Space Station Freedom (SSF). The new converters must interface three regulated power buses on SSF, which are at different voltages, with three fuel cell power buses on the Orbiter which can be at different voltages and should be tracked independently. Power exchange is to be bi-directional between the SSF and the Orbiter. The new converters must satisfy the above operational requirements with better weight, volume, efficiency, and reliability than is available from the present conventional technology. Two families of zero current DC-DC converters were developed and successfully adapted to this application. Most of the converters developed are new and are presented.
Interior point algorithm-based power flow optimisation of a combined AC and DC multi-terminal grid
Farhan Beg
2015-01-01
Full Text Available The high cost of power electronic equipment, lower reliability and poor power handling capacity of the semiconductor devices had stalled the deployment of systems based on DC (multi-terminal direct current system (MTDC networks. The introduction of voltage source converters (VSCs for transmission has renewed the interest in the development of large interconnected grids based on both alternate current (AC and DC transmission networks. Such a grid platform also realises the added advantage of integrating the renewable energy sources into the grid. Thus a grid based on DC MTDC network is a possible solution to improve energy security and check the increasing supply demand gap. An optimal power solution for combined AC and DC grids obtained by the solution of the interior point algorithm is proposed in this study. Multi-terminal HVDC grids lie at the heart of various suggested transmission capacity increases. A significant difference is observed when MTDC grids are solved for power flows in place of conventional AC grids. This study deals with the power flow problem of a combined MTDC and an AC grid. The AC side is modelled with the full power flow equations and the VSCs are modelled using a connecting line, two generators and an AC node. The VSC and the DC losses are also considered. The optimisation focuses on several different goals. Three different scenarios are presented in an arbitrary grid network with ten AC nodes and five converter stations.
DC motor operation controlled from a DC/DC power converter in pulse mode with low duty cycle
Stefanov, Goce; Kukuseva, Maja; Citkuseva Dimitrovska, Biljana
2016-01-01
In this paper pulse mode of operation of DC motor controlled by DC/DC power converter is analyzed. DC motor operation with time intervals in which the motor operates without output load is of interest. In this mode it is possible the motor to restore energy. Also, in the paper are represented calculations for the amount of the restored energy in the pulse mode operation of the motor for different duty cycles.
A Feedback Passivation Design for DC Microgrid and Its DC/DC Converters
Feifan Ji
2016-12-01
Full Text Available There are difficulties in analyzing the stability of microgrids since they are located on various network structures. However, considering that the network often consists of passive elements, the passivity theory is applied in this paper to solve the above-mentioned problem. It has been formerly shown that when the network is weakly strictly positive real (WSPR, the DC microgrid is stable if all interfaces between the microgrid and converters are made to be passive, which is called interface passivity. Then, the feedback passivation method is proposed for the controller design of various DC–DC converters to achieve the interface passivity. The interface passivity is different from the passivity of closed-loop systems on which the passivity based control (PBC concentrates. The feedback passivation design is detailed for typical buck converters and boost converters in terms of conditions that the controller parameters should satisfy. The theoretical results are verified by a hardware-in-loop real-time labotray (RTLab simulation of a DC microgrid with four generators.
Uma Maheswar Rao; S S M S Abdul Majeed; C Venkataseshaiah; R Sarathi
2002-11-01
In the present work, tracking phenomena has been studied with silicone rubber material under the a.c. and d.c. voltages following IEC-587 standards. The surface condition of the tracked zone was analysed using wide angle X-ray diffraction (WAXD) and thermogravimetric differential thermal analysis (TG–DTA) studies. The tracking time was different for a.c. and d.c. voltages.
Design of piezoelectric transformer for DC/DC converter with stochastic optimization method
Vasic, Dejan; Vido, Lionel
2016-04-01
Piezoelectric transformers were adopted in recent year due to their many inherent advantages such as safety, no EMI problem, low housing profile, and high power density, etc. The characteristics of the piezoelectric transformers are well known when the load impedance is a pure resistor. However, when piezoelectric transformers are used in AC/DC or DC/DC converters, there are non-linear electronic circuits connected before and after the transformer. Consequently, the output load is variable and due to the output capacitance of the transformer the optimal working point change. This paper starts from modeling a piezoelectric transformer connected to a full wave rectifier in order to discuss the design constraints and configuration of the transformer. The optimization method adopted here use the MOPSO algorithm (Multiple Objective Particle Swarm Optimization). We start with the formulation of the objective function and constraints; then the results give different sizes of the transformer and the characteristics. In other word, this method is looking for a best size of the transformer for optimal efficiency condition that is suitable for variable load. Furthermore, the size and the efficiency are found to be a trade-off. This paper proposes the completed design procedure to find the minimum size of PT in need. The completed design procedure is discussed by a given specification. The PT derived from the proposed design procedure can guarantee both good efficiency and enough range for load variation.
Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.
2014-01-01
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...... 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...
Design and implementation of co-operative control strategy for hybrid AC/DC microgrids
Mahmud, Rasel
This thesis is mainly divided in two major sections: 1) Modeling and control of AC microgrid, DC microgrid, Hybrid AC/DC microgrid using distributed co-operative control, and 2) Development of a four bus laboratory prototype of an AC microgrid system. At first, a distributed cooperative control (DCC) for a DC microgrid considering the state-of-charge (SoC) of the batteries in a typical plug-in-electric-vehicle (PEV) is developed. In DC microgrids, this methodology is developed to assist the load sharing amongst the distributed generation units (DGs), according to their ratings with improved voltage regulation. Subsequently, a DCC based control algorithm for AC microgrid is also investigated to improve the performance of AC microgrid in terms of power sharing among the DGs, voltage regulation and frequency deviation. The results validate the advantages of the proposed methodology as compared to traditional droop control of AC microgrid. The DCC-based control methodology for AC microgrid and DC microgrid are further expanded to develop a DCC-based power management algorithm for hybrid AC/DC microgrid. The developed algorithm for hybrid microgrid controls the power flow through the interfacing converter (IC) between the AC and DC microgrids. This will facilitate the power sharing between the DGs according to their power ratings. Moreover, it enables the fixed scheduled power delivery at different operating conditions, while maintaining good voltage regulation and improved frequency profile. The second section provides a detailed explanation and step-by-step design and development of an AC/DC microgrid testbed. Controllers for the three-phase inverters are designed and tested on different generation units along with their corresponding inductor-capacitor-inductor (LCL) filters to eliminate the switching frequency harmonics. Electric power distribution line models are developed to form the microgrid network topology. Voltage and current sensors are placed in the proper
Rodriguez, Pedro; Busquets-Monge, Sergio; Blaabjerg, Frede;
2011-01-01
This work presents the development of the space vector pulse width modulation (SVPWM) of a new multi-level converter topology. First, the proposed converter and its natural space vector diagram are presented. Secondly, a modified space vector diagram based on the virtual-vectors technique is show...
Coupled Inductor Based High Step-Up DC-DC Converter for Multi Input PV System
G. Shiny Vikram
2014-09-01
Full Text Available 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 step-up 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 a coupled inductor dc-dc converter for photovoltaic system is proposed. The circuit configuration of the proposed converter is very simple. Thus, the proposed converter has higher step-up and step-down voltage gains than the conventional bidirectional dc–dc boost/buck converter. Under same electric specifications for the proposed converter and the conventional bidirectional boost/buck converter, the average value of the switch current in the proposed converter is less than the conventional bidirectional boost/buck converter. The operating principles have been applied to multi input photovoltaic system and outputs have been observed.
AC/DC and DC/AC Converty Circuits in Power Supply Equipment%电源设备中AC/DC和DC/AC变换电路
杨碧石
2001-01-01
电源设备中根据电路变换功能来看,可分为四种类型:AC/DC、DC/AC、DC/DC、AC/AC,本文对AC/DC、DC/AC这两种变换的工作原理进行分析阐述并讨论每种电路的应用领域.
Peyghami Akhuleh, Saeed; Mokhtari, Hossein; Loh, Poh Chiang;
2016-01-01
in dc microgrids, which in most cases, are solved by a secondary control layer reinforced by an extensive communication network. To avoid such an infrastructure and its accompanied complications, this paper proposes an alternative droop scheme for low-voltage dc (LVDC) microgrid with both primary power......In an ac microgrid, a common frequency exists for coordinating active power sharing among droop-controlled sources. A common frequency is absent in a dc microgrid, leaving only the dc source voltages for coordinating active power sharing. That causes sharing error and poorer voltage regulation...... sharing and secondary voltage regulation merged. The main idea is to introduce a non-zero unifying frequency and a second power term to each dc source by modulating its converter with both a dc and a small ac signal. Two droop expressions can then be written for the proposed scheme, instead of the single...
The AC and DC Conductivity of Nanocomposites
David S. McLachlan
2007-01-01
Full Text Available The microstructures of binary (conductor-insulator composites, containing nanoparticles, will usually have one of two basic structures. The first is the matrix structure where the nanoparticles (granules are embedded in and always coated by the matrix material and there are no particle-particle contacts. The AC and DC conductivity of this microstructure is usually described by the Maxwell-Wagner/Hashin-Shtrikman or Bricklayer model. The second is a percolation structure, which can be thought to be made up by randomly packing the two types of granules (not necessarily the same size together. In percolation systems, there exits a critical volume fraction below which the electrical properties are dominated by the insulating component and above which the conducting component dominates. Such percolation systems are best analyzed using the two-exponent phenomenological percolation equation (TEPPE. This paper discusses all of the above and addresses the problem of how to distinguish among the microstructures using electrical measurements.
Haojie Wang
2016-07-01
Full Text Available It is a common practice for storage batteries to be connected to DC microgrid buses through DC-DC converters for voltage support on islanded operation mode. A feed-forward control based dual-loop constant voltage PI control for three-branch interleaved DC-DC converters (TIDC is proposed for storage batteries in DC microgrids. The working principle of TIDC is analyzed, and the factors influencing the response rate based on the dual-loop constant voltage control for TIDC are discussed, and then the method of feed-forward control for TIDC is studied to improve the response rate for load changing. A prototype of the TIDC is developed and an experimental platform is built. The experiment results show that DC bus voltage sags or swells caused by load changing can be reduced and the time for voltage recovery can be decreased significantly with the proposed feed-forward control.
A High Power Density DC-DC Converter for Distributed PV Architectures
Agamy, Mohammed S; Chi, Song; Elasser, Ahmed; Harfman-Todorovic, Maja; Jiang, Yan; Mueller, Frank; Tao, Fengfeng
2012-06-01
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.
Park, Kiwoo; Chen, Zhe
2015-01-01
This study presents a control strategy and its dynamic analysis of a high-power dc-dc converter, which is constructed with the parallel-connected single active bridge (SAB) dc-dc converters for dc-grid wind farm applications. The structural and operational characteristics of the SAB dc-dc converter...... have several advantages for high-power applications, and the modular concept of the parallel-connected converter is highly beneficial especially for offshore wind farm applications in terms of maintenance cost and fault tolerance. To justify the feasibility of the parallel-connected SAB dc-dc converter...... for dc-grid wind farm applications, an input voltage control method based on the PI control will be introduced and the dynamics of the overall system will be analysed. The analysis results are to be verified by means of simulations and experiments....
DC-DC Converter Topology Assessment for Large Scale Distributed Photovoltaic Plant Architectures
Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Sabate, Juan A; Steigerwald, Robert L; Jiang, Yan; Essakiappan, Somasundaram
2011-07-01
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.
Modular Power System Configured with Standard Product Hybrid DC-DC Converters Project
National Aeronautics and Space Administration — VPT proposes an innovative concept whereby complex, multiple-output, DC-DC converter systems can be configured through use of only 2 standard product hybrid DC-DC...
Funabiki, Shigeyuki; Yamamoto, Masayoshi
Renewable energy such as wind force and solar light has collected the attention as alternative energy sources of fossil fuel. An energy storage system with an electric double-layer capacitor (EDLC), which balances the demand and supply power, is required in order to introduce the electric power generating system that utilizes renewable energy. Currently, the research and development of these energy storage systems are actively carried out. In the energy storage system with an EDLC, the DC/DC converter having the function of the bidirectional power flow and the buck/boost performance is essential as an interface and power control circuit. There are two types of the bidirectional buck/boost DC/DC converters. One type consists of two buck/boost DC/DC converters with one reactor. The other type consists of two sets of two-quadrant DC/DC converters with one reactor. This paper discusses the comparison of these types of DC/DC converters with bidirectional power flow and buck/boost performance. The two types of DC/DC converters are estimated for their application to the energy storage system with the EDLC. As the voltage endurance of the device is lower and the mean current is smaller in the latter type of converter despite of having twice the number of devices compared to the former, the latter type of converter has the advantage of a smaller reactor, i.e., core volume and loss, and lower loss in the converter.
Najjar, Mohammad; Moeini, Amirhossein; Dowlatabadi, Mohammadkazem Bakhshizadeh
2016-01-01
In this paper, the power quality standards such as IEC 61000-3-6, IEC 61000-2-12, EN 50160, and CIGRE WG 36-05 are fulfilled for single- and three-phase medium voltage applications by using Selective Harmonic Mitigation-PWM (SHM-PWM) in a Cascaded H-Bridge (CHB) converter. Furthermore, the ER G5....../4 power quality standard, which has the strictest grid codes at medium voltage level, will also be met in the whole range of the modulation indices. In order to achieve this goal, symmetrical CHB with variable DC Links are employed, while the converter has a low number of switching transitions. In other...
A compact versatile matrix converter to integrate various energy resources to utility network
Liu, Xiong; Loh, Poh Chiang; Wang, Peng;
2011-01-01
This paper proposes a multi-inputs versatile matrix converter (VMC) to integrate various energy resources and energy storages to a power grid. The VMC is developed based on a traditional indirect matrix converter (IMC) and a nineswitch converter. The six input terminals provide flexibility...... for the connection of two three-phase AC sources or one threephase AC and three DC sources, which make it possible to integrate both DC and AC renewable sources in a single gridtied power electronics interface. The control and modulation schemes are proposed to extract the commanded current from the input AC...
Deivasundari, P.; Geetha, R.; Uma, G.; Murali, K.
2013-07-01
DC-DC converters act as a black box to study various bifurcations. In the present study, the influence of external periodic interference signal in the input of DC-DC voltage-mode controlled buck converter has been considered. It is found that the presence of sinusoidal or saw-tooth interference signal whose frequency is comparable with the switching frequency of the converter or its rational multiples manifests as remerging chaotic band attractors (or Feigenbaum trees) and intermittent chaos. However, the presence of sinusoidal interference signal having irrational frequency ratios with the switching frequency of the converter leads to quasi-periodic route to chaos. The study was carried out both theoretically and experimentally.
Cryogenic Evaluation of an Advanced DC/DC Converter Module for Deep Space Applications
Elbuluk, Malik E.; Hammoud, Ahmad; Gerber, Scott S.; Patterson, Richard
2003-01-01
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.
High Voltage Coil Current Sensor for DC-DC Converters Employing DDCC
M. Drinovsky
2015-12-01
Full Text Available Current sensor is an integral part of every switching converter. It is used for over-current protection, regulation and in case of multiphase converters for balancing. A new high voltage current sensor for coil-based current sensing in DC-DC converters is presented. The sensor employs DDCC with high voltage input stage and gain trimming. The circuit has been simulated and implemented in 0.35 um BCD technology as part of a multiphase DC-DC converter where its function has been verified. The circuit is able to sustain common mode voltage on the input up to 40 V, it occupies 0.387*0.345 mm2 and consumes 3.2 mW typically.
Reliability-Oriented Design of LC Filter in Buck DC-DC Converter
Liu, Yi; Huang, Meng; Wang, Huai;
2015-01-01
State-of-the-art LC filter design of buck DC-DC converter is based on the specifications of voltage and current ripples and constrains in power density and cost. Since lifetime is an important performance factor in reliability critical applications, this digest proposes a method to optimize...... an optimized LC filter design to fulfill the required lifetime. The theoretical analysis and simulation study are presented which are verified by the experimental results from a buck converter prototype....
2014-01-01
The two basic topologies of switch mode DC-DC converters (Buck and Boost) are analyzed with a view of their use in PV (photovoltaic) systems, as the photovoltaic generator exhibits non-linear characteristics due to the change in environmental condition and load variation. As the efficiency of PV panels is low it becomes mandatory to extract maximum power from the PV panel at a given period of time. Several MPPT algorithms with different types of converters are being proposed f...
Differential Mode EMI Filter Design for Isolated DC-DC Boost Converter
Makda, Ishtiyaq Ahmed; Nymand, Morten
2014-01-01
is identified first. The DM noise model is then established and based on the harmonic analysis of the noise source voltage waveform, the complete Differential Mode EMI filter, including the filter resonance damping branch, is designed for a 3kW isolated dc-dc boost converter. The noise model and its theoretical......A Differential Mode EMI filter for a low input voltage high-current isolated dc-dc boost converter is designed and presented in this paper. The primary side Differential Mode noise voltage is low due to the high transformer turn ratio, however, the input current is very high and since the EMI limit...... also does not change for such converters, it requires greatly optimized design approach for the filter including the correct sizing of the filter components. A complete analytical filter design process is carried out such a way that the Differential Mode noise voltage source in the converter...
AC-DC integrated load flow calculation for variable speed offshore wind farms
Zhao, Menghua; Chen, Zhe; Blaabjerg, Frede
2005-01-01
This paper proposes a sequential AC-DC integrated load flow algorithm for variable speed offshore wind farms. In this algorithm, the variable frequency and the control strategy of variable speed wind turbine systems are considered. In addition, the losses of wind turbine systems and the losses...... of converters are also integrated into the load flow algorithm. As a general algorithm, it can be applied to different types of wind farm configurations, and the load flow is related to the wind speed....
SOFT-SWITCHED HIGH STEP-UP DC-DC CONVERTER WITH HIGH VOLTAGE GAIN
J.C. PAUL IMMANUEL
2013-04-01
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.
A Three-Phase Bidirectional DC-DC Converter for Automotive Applications
Su, Gui-Jia [ORNL; Tang, Lixin [ORNL
2008-01-01
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.
Computer-aided analysis and simulation of switched dc-dc converters
Lee, F. C.; Yu, Y.
1978-01-01
State space techniques are employed to derive an equivalent nonlinear recurrent time-domain model that describes the switched dc-dc converter behavior exactly. This model is employed effectively to analyze both large signal behavior by propagating the recurrence equation and matching boundary conditions through digital computation and small signal behavior by linearizing it about the equilibrium state.
Power Controllability of Three-phase Converter with Unbalanced AC Source
Ma, Ke; Liserre, Marco; Blaabjerg, Frede
2013-01-01
Three-phase DC-AC power converters suffer from power oscillation and overcurrentt problems in case of unbalanced AC source voltage that can be caused by grid/generator faults. Existing solutions to handle these problems are properly selecting and controlling the positive and negative sequence...... currents. In this work a new series of control strategies which utilize the zero-sequence components are proposed to enhance the power control ability under this adverse conditions. It is concluded that by introducing proper zero sequence current controls and corresponding circuit configurations, the power...... converter can enable more flexible control targets, achieving better performances in the delivered power and load current when suffering from unbalanced AC sources....
Power Controllability of Three-phase Converter with Unbalanced AC Source
Ma, Ke; Chen, Wenjie; Liserre, Marco;
2015-01-01
Three-phase DC-AC power converters suffer from power oscillation and overcurrent problems in case of unbalanced AC source voltage that can be caused by grid/generator faults. Existing solutions to handle these problems are properly selecting and controlling the positive and negative sequence...... currents. In this work a new series of control strategies which utilize the zerosequence components are proposed to enhance the power control ability under this adverse condition. It is concluded that by introducing proper zero sequence current controls and corresponding circuit configurations, the power...... converter can enable more flexible control targets, achieving better performances in the delivered power and load current when suffering from unbalanced AC voltage....
Magnetically coupled high-gain Y-source isolated DC/DC converter
Siwakoti, Yam P.; Loh, Poh Chiang; Blaabjerg, Frede;
2014-01-01
A new form of magnetically coupled DC/DC converter is proposed for medium power applications (250 W to 2 kW), requiring a high-voltage gain, short inductive charging time and galvanic isolation. The proposed converter can be realised using a unique Y-source impedance network and a two-switch push......-pull circuit with voltage-doubling rectification. The converter's voltage gain is presently not matched by any other converter operating at the same switch duty ratio. The converter also has more degrees of freedom in design for setting the desired gain than other converters, and hence can better meet...... the demands of many applications. The operating principles of the converter have been analysed mathematically, and are verified by both simulation and experiment....
Wide-Range Adaptive RF-to-DC Power Converter for UHF RFIDs
Ouda, Mahmoud H.
2016-07-27
A wide-range, differential, cross-coupled rectifier is proposed with an extended dynamic range of input RF power that enables wireless powering from varying distances. The proposed architecture mitigates the reverse-leakage problem in conven- tional, cross-coupled rectifiers without degrading sensitivity. A prototype is designed for UHF RFID applications, and is imple- mented using 0.18 μ m CMOS technology. On-chip measurements demonstrate a sensitivity of − 18 dBm for 1 V output over a 100 k Ω load and a peak RF-to-DC power conversion efficiency of 65%. A conventional, fully cross-coupled rectifier is fabricated along- side for comparison and the proposed rectifier shows more than 2 × increase in dynamic range and a 25% boosting in output voltage than the conventional rectifier
DC-DC converter with a wide load range and a wide input-voltage range
Ting, Y.
2015-01-01
This thesis investigated the possibility of increasing the efficiency of a DC-DC converter over a wide load range and a wide input-voltage range based on the Single Active Bridge (SAB) topology with two approaches. The first approach involved making changes to the topology whereas the second made us
Multistability and hidden attractors in a multilevel DC/DC converter
Zhusubaliyev, Zhanybai T.; Mosekilde, Erik
2015-01-01
for the hidden set in most cases has been so complicated that special analytic and/or numerical techniques have been required to locate the set. By simulating the model of a multilevel DC/DC converter that operates in the regime of high feedback gain, the paper illustrates how pulse-width modulated control can...
Regulation of a lightweight high efficiency capacitator diode voltage multiplier dc-dc converter
Harrigill, W. T., Jr.; Myers, I. T.
1976-01-01
A method for the regulation of a capacitor diode voltage multiplier dc-dc converter has been developed which has only minor penalties in weight and efficiency. An auxiliary inductor is used, which only handles a fraction of the total power, to control the output voltage through a pulse width modulation method in a buck boost circuit.
Regulation of a lightweight high efficiency capacitor diode voltage multiplier dc-dc converter
Harrigill, W. T., Jr.; Myers, I. T.
1976-01-01
A method for the regulation of a capacitor diode voltage multiplier dc-dc converter has been developed which has only minor penalties in weight and efficiency. An auxiliary inductor is used, which only handles a fraction of the total power, to control the output voltage through a pulse width modulation method in a buck boost circuit.
A Family of Four Quadrant DC/DC Converters with Reduced Number of Components
Mostaan, Ali; Soltani, Mohsen
2015-01-01
A family of four quadrant DC/DC converters is presented in this paper. Compare with existing four quadrant DC/DC converters that have been introduced in literature, the proposed converters have lower number of components. There are two bidirectional switches, two coupled inductors and one capacit...... effect is minimized in these converters. The effectiveness of the proposed converters is validated with simulation using MATLAB/SIMULINK....
A Fixed-Frequency Bidirectional Resonant DC-DC Converter Suitable for Wide Voltage Gain Range
Shen, Yanfeng; Wang, Huai; Al-Durra, Ahmed;
2017-01-01
This paper proposes a new bidirectional resonant dc-dc converter suitable for wide voltage gain range applications (e.g., energy storage systems). The proposed converter overcomes the narrow voltage gain range of conventional resonant DC-DC converters, and meanwhile achieves high efficiency...... and characteristics of the proposed converter are analyzed. Finally, a 1-kW converter prototype is built and the experimental results verify the theoretical analyses....
LI Jian; JIANG Tianyan; HE Zhiman; CHENG Changkui; BAO Lianwei
2012-01-01
The converter transformer is one of the most critical equipments in high-voltage direct current transmission systems.Valve-side windings have to withstand complex stresses combined of AC,DC,and pulsed voltages.Partial discharges（PDs） can thus easily occur in oil-impregnated paper insulation.The current paper presents the statistical phase-resolved distributions of partial discharges in oil-paper insulation under combined AC and DC voltage stress.First,the voltages in the converter transformer were analyzed.In the experiments,four artificial insulation defect models were designed to generate PD signals under AC-DC combined voltage stress detected by a Rogowski coil sensor.Histograms including the φ-q-n data of these PD signals were created.The variations of φ-q-n data generated by PDs in different insulation defect models were analyzed while increasing the test voltage.Experimental results showed that the PD phase-resolved distributions of different insulation defect models were different from one another.The findings of the current study are useful in further research on the mechanism and pattern recognition of PDs in converter transformers.
Ohri, A. K.; Wilson, T. G.; Owen, H. A., Jr.
1977-01-01
A procedure is presented for designing air-gapped energy-storage reactors for nine different dc-to-dc converters resulting from combinations of three single-winding power stages for voltage stepup, current stepup and voltage stepup/current stepup and three controllers with control laws that impose constant-frequency, constant transistor on-time and constant transistor off-time operation. The analysis, based on the energy-transfer requirement of the reactor, leads to a simple relationship for the required minimum volume of the air gap. Determination of this minimum air gap volume then permits the selection of either an air gap or a cross-sectional core area. Having picked one parameter, the minimum value of the other immediately leads to selection of the physical magnetic structure. Other analytically derived equations are used to obtain values for the required turns, the inductance, and the maximum rms winding current. The design procedure is applicable to a wide range of magnetic material characteristics and physical configurations for the air-gapped magnetic structure.
High Frequency AC Inductor Analysis and Design for Dual Active Bridge (DAB) Converters
Zhang, Zhe; Andersen, Michael A. E.
2016-01-01
The dual active bridge (DAB) converter is an isolated bidirectional dc-dc topology which is the most critical part for the power conversion systems such as solid-state transformers (SST). This paper focuses on analysis and design of high frequency ac inductors which are the power interfacing...
Disrupted bandcount doubling in an AC-DC boost PFC circuit modeled by a time varying map
Avrutin, Viktor; Zhusubaliyev, Zhanybai T.; Aroudi, Abdelali El;
2016-01-01
averaged models. In this paper, we derive a time varying discretetime map modeling the behavior of a power factor correction AC-DC boost converter. This map is derived in closed-form and is able to faithfully reproduce the system behavior under realistic conditions. In the chaotic regime the map exhibits...
Three-phase Resonant DC-link Converter
Munk-Nielsen, Stig
no additional power electric components is eliminating the high voltage peaks associated with the resonant circuit. The resonant link voltage peaks are limited below 2.1 times the DC link voltages. A new principle eliminating former resonant converter stability problems are proposed, implemented and tested......The purpose of the project is to develop a three-phase resonant converter suitable for standard speed drives. The motivation for working with resonant converters is found in the problem of the standard converter type used today. In standard converter type Pulse Width Modulated-Voltage Source....... The high speed of the switches cannot be fully utilizied. By using a parallel resonant converter the switching happens at low or zero voltage which reduses switch losses. The dv/dt is controlled by the resonant circuit, and it is therefore reduced significantly. The perspective using a resonant converter...
Development of DC-DC converters for the upgrade of the CMS pixel detector
Feld, Lutz; Karpinski, Waclaw; Klein, Katja; Sammet, Jan; Wlochal, Michael [RWTH Aachen University (Germany)
2012-07-01
Around 2017, the pixel detector of the CMS experiment at LHC 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 available supply cables. Therefore it is foreseen to place DC-DC converters close to the front-end electronics, allowing to provide the power at higher voltages and thereby to facilitate the supply of the required currents with the present cable plant. The talk introduces the foreseen powering scheme of the pixel upgrade and summarizes the results of system test measurements with CMS pixel sensor modules, radiation tolerant DC-DC converters and the full power supply chain of the pixel detector. In addition, measurements of the converter efficiency and performance before, after and during thermal cycling are presented.
Harmonic-free line-commutated ac/dc rectifiers
Villablanca, Miguel E. [Electrical Engineering Department, University of Santiago, P.O. Box 10233, Santiago (Chile)
2009-11-15
In this paper both a method and apparatus are applied to different configurations of line-commutated ac/dc rectifiers to reduce the distortion of currents flowing from the ac supply. The load may be either inductive or capacitive. The technology involves an accurate shaping of the dc current by using two self-commutated switches. This dc-current shaping is reflected back into the shaping of the ac input currents, which become pure sine waves. Thyristor-based rectifying operation is possible with a simple control circuit, which is able to deal with both rapid load variations and failures in the self-commutated switches. Furthermore, the overlap conduction of bridge thyristors is eliminated completely. Experimental verification is provided from a 400-V 30-kVA 50-Hz laboratory prototype. (author)
级联Buck-Boost PFC变换器建模及仿真%Modeling and Simulation of Cascaded Buck-Boost AC-DC Converter
郭学军; 刘以建
2016-01-01
文中采用状态空间平均法对级联Buck-Boost AC-DC变换器进行了小信号建模分析,提出了一种基于瞬时功率守恒的新的平均电流控制(ACC)技术.通过这种新的控制技术能够使得输入电流波形接近正弦波且与输入电压同相位,总的谐波扰动小于3％.最后通过PSIM仿真实验,验证了这种新的控制方法的可行性和优越性.
Hu, Zhenda; Wu, Rui; Yang, Xiaodong;
2014-01-01
With the development of High Voltage DC Transmission (HVDC) technology, there will be more and more HVDC-AC hybrid transmission system in the world. A basic challenge in HVDC-AC hybrid transmission systems is to optimize the power sharing between DC and AC lines, which become more severe when...... supplying power for passive networks, as the surplus power can only flow back to power grids through the AC lines. To deal with this issue, it demands not only accurate system capability design but also flexible power control strategy of power converters in VSC-HVDC. This paper proposes a novel power...
R. Silva-Ortigoza
2014-01-01
Full Text Available This paper presents a hierarchical controller that carries out the angular velocity trajectory tracking task for a DC motor driven by a DC/DC Buck converter. The high level control is related to the DC motor and the low level control is dedicated to the DC/DC Buck converter; both controls are designed via differential flatness. The high level control provides a desired voltage profile for the DC motor to achieve the tracking of a desired angular velocity trajectory. Then, a low level control is designed to ensure that the output voltage of the DC/DC Buck converter tracks the voltage profile imposed by the high level control. In order to experimentally verify the hierarchical controller performance, a DS1104 electronic board from dSPACE and Matlab-Simulink are used. The switched implementation of the hierarchical average controller is accomplished by means of pulse width modulation. Experimental results of the hierarchical controller for the velocity trajectory tracking task show good performance and robustness against the uncertainties associated with different system parameters.
A DC-DC Converter Efficiency Model for System Level Analysis in Ultra Low Power Applications
Benton H. Calhoun
2013-06-01
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.
High voltage conversion ratio, switched C & L cells, step-down DC-DC converter
Pelan, Ovidiu; Muntean, Nicolae; Cornea, Octavian;
2013-01-01
The paper presents a high voltage conversion ratio DC-DC step-down topology obtained from a classical buck converter associated with an input switched-capacitor cell and an output switched-inductor cell. Analytical descriptions, the voltage and current limits of the main components are synthesized...... in a comparative form, related to the classical buck structure, in order to emphasis the advantages of the proposed converter. Digital simulations and experimental results obtained with a built prototype are compared. From the first evaluation, the proposed converter is expected to be effectively used at input...
Ultra-high Efficiency DC-DC Converter using GaN Devices
Ramachandran, Rakesh
2016-01-01
with the PCB layout and the magnetics. This thesis mainly covers the design and implementation of various high efficiency isolated dcdc converters in the range of 1 to 2.5 kW of output power. Both hard-switched and soft-switched topologies in isolated dc-dc converters has been studied and realized......The demands for high efficiency dc-dc power converters are increasing day by day in various applications such as telecommunication, data-centers, electric vehicles and various renewable energy systems. Silicon (Si) has been used as the semiconductor material in majority of the power devices...... for many decades. However, the rate of improvement slowed as the silicon power materials asymptotically approached its theoretical bounds. Compared to Si, wideband gap materials such as Silicon Carbide (SiC) and Gallium Nitride (GaN) are promising semiconductors for power devices due to their superior...
5 kW DC/DC converter for hydrogen generation from photovoltaic sources
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
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)
SUBCONTRACT REPORT: DC-DC Converter for Fuel Cell and Hybrid Vehicles
Marlino, Laura D [ORNL; Zhu, Lizhi [Ballard Power Systems/Siemens VDO
2007-07-01
The goal of this project is to develop and fabricate a 5kW dc-dc converter with a baseline 14V output capability for fuel cell and hybrid vehicles. The major objectives for this dc-dc converter technology are to meet: Higher efficiency (92%); High coolant temperature,e capability (105 C); High reliability (15 Years/150,000miles); Smaller volume (5L); Lower weight (6kg); and Lower cost ($75/kW). The key technical challenge for these converters is the 105 C coolant temperatures. The power switches and magnetics must be designed to sustain these operating temperatures reliably, without a large cost/mass/volume penalty.
Practical Design Guidelines of qZSI Based Step-Up DC/DC Converter
Zakis, Janis; Vinnikov, Dmitri; Roasto, Indrek; Jalakas, Tanel
2010-01-01
This paper presents some design guidelines for a new voltage fed step-up DC/DC isolated converter. The most significant advantage of proposed converter is voltage buck-boost operation on single stage. The most promising application for proposed converter is in the field of distributed power generation e.g. fuel cells or photovoltaic. The most sensitive issues - such as power losses caused by high currents in the input side of converter and high transient overvoltages across the inverter bridge caused by stray inductances were discussed and solved. The proposals and recommendations to overcome these issues are given in the paper. The Selection and design guidelines of converter elements are proposed and explained. The prototype of proposed converter was built and experimentally tested. Some results are presented and evaluated.
Novel Full-bridge ZVS DC-DC Converter with an Clamp Diodes
Guangqun, Nan; Xue, Hu
The two arms of this converter all work at zero-voltage switching condition, that bring many advantages, such as little loss of power, simple control, etc. But these also exists some problems, such as parasitic oscillation on the output rectifier diodes. A novel full-bridge ZVS PWM DC-DC converter which adopts two clamping diodes in the first side of the transformer is proposed to reduce the parasitic oscillation in this paper. In this paper, It heavily analyzes the realization process of their soft-switching and the reason of related issues and solution, we establishes simulation model and simulates using orCAD. Finally,a 5 kW ZVS PWM DC-DC converter Prototype in that TMS320F2812 is the core controlled chip has been set up, and the experiments showed us the validation of the correlative theory.
Embedded Controlled Isolated Bidirectional Full-Bridge DC-DC Converter with Flyback Snubber
D. Kirubakaran
2012-01-01
Full Text Available An isolated bidirectional full-bridge DC-DC converter with flyback snubber for supplying a resistive load is simulated and experimentally verified. The DC-DC converter for high conversion ratio, high output power, and soft start-up capability is presented in this paper. The circuit consists of a capacitor, a diode, and a flyback converter. These components help to clamp the voltage spikes caused by the current difference between the current fed inductor and leakage inductance of the isolation transformer. The switches are operated by soft-switching technology. The suppression of inrush current which is usually found in the boost mode start-up transition is presented here. The simulated and experimental results for output voltage, output current, and power for both buck and boost modes are presented.
Sliding-mode control of single input multiple output DC-DC converter
Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang
2016-10-01
Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.
A Novel PPFHB Bidirectional DC-DC Converter for Supercapacitor Application
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael Andreas E.
2009-01-01
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 described in detail, ZVS conditions are discussed, parameters are designed, and the experimental results...
Planar integrated magnetics design in wide input range DC-DC converter for fuel cell application
Ouyang, Ziwei; Zhang, Zhe; Thomsen, Ole Cornelius;
2010-01-01
, hereby increasing the power density of converters. A new planar integrated magnetics (PIM) technique for a phase-shift plus duty cycle controlled hybrid bi-directional DC/DC converter is presented and investigated in this paper. The main magnetic components including one boost inductor and two......In the most power electronics converters, the overall volume is mainly determined by the number of parts and the size of passive components. Integrated magnetics and planar magnetics techniques therefore have been an excellent option in order to reduce the count and the size of magnetic components...
Five-Level Active-Neutral-Point-Clamped DC/DC Converter
Liu, Dong; Deng, Fujin; Chen, Zhe
2016-01-01
reliability. Furthermore, a capacitor voltage control strategy by alternating two operation modes of the proposed modulation strategy is proposed to balance the voltage of the flying capacitor, which ensures multi-level voltages producing. Finally, the performance of the proposed converter and control......Multi-level converters are getting more and more attentions because of their obvious merits such as lower voltage stress and harmonic, smaller size of output filters, and so on. In this paper, a five-level active-neutral-point-clamped (5L-ANPC) dc/dc converter is proposed for power transfer...
Bhaskar, Mahajan Sagar; Kulkarni, Rishi M.; Padmanaban, Sanjeevi Kumar;
2016-01-01
In this paper hybrid non isolated/ non inverting Nx interleaved DC-DC multilevel Boost Converter for renewable energy applications is presented. The presented hybrid topology is derived from the conventional interleaved converter and the Nx Multilevel boost converter. In renewable energy...... applications, generated energy cannot be directly used at application end. In most of the cases it needs to be stepped up with DC-DC converter at operating voltage levels as per the requirement of the application. Though conventional boost converter can theoretically be used for this purpose, but obtaining....... The advantages of presenting topology of DC-DC converter are high voltage conversion, reduce ripple, low voltage stress, non inverting without utilizing the high duty and transformer. The main advantage of presented topology is more number of levels can be increased by adding capacitor and diode circuitry...
Bifurcations in a Generalization of the ZAD Technique: Application to a DC-DC Buck Power Converter
Ludwing Torres
2012-01-01
Full Text Available A variation of ZAD technique is proposed, which is to extend the range of zero averaging of the switching surface (in the classic ZAD it is taken in a sampling period, to a number of sampling periods. This has led to a technique that has been named -ZAD. Assuming a specific value for =2, we have studied the 2-ZAD technique. The latter has presented better results in terms of stability, regarding the original ZAD technique. These results can be demonstrated in different state space graphs and bifurcation diagrams, which have been calculated based on the analysis done about the behavior of this new strategy.
Wide Temperature Range DC-DC Boost Converters for Command/Control/Drive Electronics Project
National Aeronautics and Space Administration — We shall develop wide temperature range DC-DC boost converters that can be fabricated using commercial CMOS foundries. The boost converters will increase the low...
Abrahamsson, Lars; Östlund, Stefan; Söder, Lennart
2012-01-01
In this paper an alternative railway power systems design based on an HVDC feeder is studied. The HVDC feeder is connected to the catenary by converters. Such an HVDC line is also appropriate for DC-fed railways and AC-fed railways working at public frequency. A unit commitment optimal power flow model has been developed and is applied on a test system. In this paper, the model is presented in detail. The model, in the form of an MINLP program, uses unified AC-DC power flow to minimize the en...
Loss characterization of Mo-doped FeNi flake for DC-to-DC converter and MHz frequency applications
Zhou, Y; Kou, XM; Mu, MK; McLaughlin, BM; Chen, X; Parsons, PE; Zhu, H; Ji, A; Lee, FC; Xiao, JQ
2012-04-01
Magnetic core materials with low loss, high magnetic induction, large permeability, and high working frequencies above 1 MHz are in high demand in the next generation of miniaturized power electronic devices. Magnetic flake based composite materials have been developed to take advantage of high operating frequency ranges, low eddy current losses, high magnetic induction, and low cost fabrication methods. In this study, Mo-doped FeNi flakes with thicknesses of 0.4 +/- 0.2 mu m to 1.6 +/- 0.5 mu m have been successfully fabricated with high energy ball milling. The lateral size of the flake is around 100 mu m. After being hot-pressed with polymers, all of the samples show initial permeability higher than 40 in the frequency range up to 10 MHz and a loss tangent lower than 0.1. At high excitations, the composite materials show core losses 5 times lower than that of Fe flakes at 800 kHz. (C) 2012 American Institute of Physics. [doi:10.1063/1.3677310
Performance Analysis of Various DC-DC Converters with Optimum Controllers for PV Applications
R. Sankarganesh
2014-08-01
Full Text Available Alternative vehicles to Internal Combustion Engines (ICE, for instance the electric vehicle is becoming popular. Electric Vehicles (EV are pollution free and cost effective because the fossil fuel cost increases day by day. These factors make people passion for electric vehicles. Electrical energy demand necessitates charging of electric vehicles using renewable energy. Among the different renewable energy resources, Photovoltaic (PV cells are suitable for EV. The PV output power capacity is still low, so efforts continue to develop the PV converter and its controller, aiming for higher power-extracting efficiency. The PV system requires a proper DC-DC converter with optimum controller to deliver its maximum power. This study analyses the various DC-DC converters such as buck, boost, cuk and modified cuk converters to find the solution for maximum efficiency. In this study in addition to converters, various Maximum Power Point Tracking (MPPT methods, such as Perturb and Observe, Incremental Conductance along with a proposed algorithm called Brain Emotional Learning Based Intelligent Controller (BELBIC has been analyzed. The operation of the BELBIC is based on the emotion processing mechanism in the brain. This intelligent control is stimulated by the limbic system of the mammalian brain. The performance analysis of the converters and MPPT methods are simulated using MATLAB/SIMULINK. Furthermore, experimental results are presented in order to validate the modified cuk converter with proposed BELBIC algorithm.
DC/DC开关变换器混沌现象研究综述%Summary of the Research on Chaos Phenomena of DC/DC Converter
蔚洋; 冯平
2012-01-01
DC/DC功率开关变换器是开关电源的核心部分,通过对其混沌现象的研究可以更加深刻地认识DC/DC变换器的本质,也会在将来基于混沌现象提出新的设计方法和控制策略,实现现有DC/DC变换器无法达到的性能.本文介绍了DC/DC变换器混沌现象的研究现状,对DC/DC变换器混沌现象的基本建模方法进行了综合对比分析,展望了DC/DC变换器混沌研究的发展和未来应用前景.%DC/DC power switch converter is the core part of switch power supply. Through the study of chaos phenomena, the essence of DC/DC converter can be more deeply understand, the new design methods and control strategies based on chaos phenomena will be put forward in the future, to achieve the existing DC/DC converter that cannot reach. This paper introduces the research status of the DC/DC converter chaos phenomena, makes comprehensive comparative analysis of the basic modeling method of DC/DC converter chaos phenomena, and looks to its development and future application prospect.
Advanced power electronics converters PWM converters processing AC voltages
dos Santos, Euzeli
2014-01-01
This book covers power electronics, in depth, by presenting the basic principles and application details, which can be used both as a textbook and reference book. Introduces a new method to present power electronics converters called Power Blocks Geometry. Applicable for courses focusing on power electronics, power electronics converters, and advanced power converters. Offers a comprehensive set of simulation results to help understand the circuits presented throughout the book
SANJEEV SINGH
2010-12-01
Full Text Available Permanent magnet brushless DC motor (PMBLDCM drives are being employed in many variable speed applications due to their high efficiency, silent operation, compact size, high reliability, ease of control, and low maintenance requirements. These drives have power quality problems and poor power factor at input AC mains as they are mostly fed through diode bridge rectifier based voltage source inverters. To overcome such problems a single-phase single-switch power factor correction AC-DC converter topology based on a Cuk converter is proposed to feed voltage source inverters based PMBLDCM. It focuses on the analysis, design and performance evaluation of the proposed PFC converter topology for a 1.5 kW, 1500 rpm, 400 V PMBLDCM drive used for an air-conditioning system. The proposed PFC converter topology is modelled and its performance is simulated in Matlab-Simulink environment and results show an improved power quality and good power factor in wide speed range of the drive.
MPP-Tracking DC-DC converters in Photovoltaic applications. Implementation, modeling and analysis
Leppaeaho, J.
2011-07-01
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
R. NOROOZIAN; M. ABEDI; G.B. GHAREHPETIAN; S. H. HOSSEINI
2009-01-01
A novel control strategy for the load converter supplying the unbalanced AC load in a DC isolated distribution system is presented. The control algorithm results in balanced and sinusoidal load voltages under unbalanced AC loading. The unbalanced load is characterized in the d-q-0 rotating coordinate based on symmetrical sequence components. Also, the mathematical model of the load converter in both a-b-c and d-q-0 coordinates is derived by using the average large signal model. Then, two control strategies for the load converter are presented. The first one uses the conventional d-q-0 controller to ensure the voltage and current regulation. The second one is a newly proposed control strategy based on the decomposition of the voltage and current into instantaneous positive, negative, and zero sequences. These three sequences are controlled independently in their own reference frames as DC signals. The performance of the load converter using these two control strategies is compared. Simulation results show the validity and capability of the newly proposed control strategy.
Impute DC link (IDCL) cell based power converters and control thereof
Divan, Deepakraj M.; Prasai, Anish; Hernendez, Jorge; Moghe, Rohit; Iyer, Amrit; Kandula, Rajendra Prasad
2016-04-26
Power flow controllers based on Imputed DC Link (IDCL) cells are provided. The IDCL cell is a self-contained power electronic building block (PEBB). The IDCL cell may be stacked in series and parallel to achieve power flow control at higher voltage and current levels. Each IDCL cell may comprise a gate drive, a voltage sharing module, and a thermal management component in order to facilitate easy integration of the cell into a variety of applications. By providing direct AC conversion, the IDCL cell based AC/AC converters reduce device count, eliminate the use of electrolytic capacitors that have life and reliability issues, and improve system efficiency compared with similarly rated back-to-back inverter system.
Guo, Xiaoqiang; Xu, David; Guerrero, Josep M.
2015-01-01
instability. Conventionally, with a given switching frequency and rated voltage, the current ripple can be reduced by increasing the dc-link inductor, but it leads to bulky size, high cost and slow dynamic response. In order to solve this problem, this paper reveals that the current ripple can......Back-to-back converters have been typically used to interconnect the microgrids. For a back-to-back current source converter, the dc-link current ripple is one of the important parameters. A large ripple will cause the electromagnetic interference, undesirable high-frequency losses, and system...
Cocquerelle, J.L.
1996-07-01
This book deals with the analysis of power electronic converters and of their conducted disturbances, in particular the emission of harmonic currents. The basic electrical and electrotechnical knowledge is recalled first (power distribution systems, transformers..) and then the different types of converters are presented in a first chapter and illustrated with a description and a numerical analysis of each of them: DC-DC, AC-AC, AC-DC and DC-AC converters. A second chapter is devoted to low voltage single-phase and tri-phase distribution systems and transformers. (J.S.)
A New Zero Voltage Switching Buck-Boost Type DC-DC Converter
Majid Delshad
2010-03-01
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.
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
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
Direct switching control of DC-DC power electronic converters using hybrid system theory
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
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.
The good routing of a non-insulated DC/DC converter; Bien router un convertisseur DC/DC non-isole
Lenoir, E.
2001-03-01
DC to DC converters are important sources of magnetic and electric fields with frequencies that can exceed 100 MHz. Thus, their positioning on a circuit board is of prime importance to minimize the magnetic and capacitive couplings with other parts and components of the circuit. This article summarizes the important rules to follow for a good routing of non-insulated switching DC/DC converters: taking the ohmic voltage drops into consideration, managing the MOSFET commutation, limiting the current loop disturbances, correct routing of power tracks. (J.S.)
Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Siano, Pierluigi
2016-01-01
converter with inbuilt voltage-lift technique and overcome the aforementioned deficiencies. Further, the control strategy is adapted based on proportional-integral (P-I) and fuzzy logic, closed-loop controller to regulate the outputs and ensure the performances. Complete hardware prototype of EHV converter......This paper presents the control strategies by Proportional-Integral (P-I) and Fuzzy Logic (FL) for a DC-DC boost power converter for high output voltage configuration. Standard DC-DC converters are traditionally used for high voltage direct current (HVDC) power transmission systems. But, lack its...... performances in terms of efficiency, reduced transfer gain and increased cost with sensor units. Moreover, the internal self-parasitic components reduce the output voltage and efficiency of classical high voltage converters (HVC). This investigation focused on extra high-voltage (EHV) DC-DC boost power...
Pledl, Georg; Lutter, Peter [Finepower GmbH, Ismaning (Germany)
2010-07-01
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.)
Measurement of AC and DC Insulation Leakage in Platinum Resistance Thermometers up to 960 °C
García, C.; del Campo, D.; Raso, F.
2011-08-01
It is well known that insulation leakage at high temperatures can be one of the major contributions to uncertainties in measured temperatures above 600 °C. On the one hand, this insulation leakage shunts the sensor resistor leading to systematic errors in the measured temperatures, which are, in principle, characteristics of each thermometer. On the other hand, at high temperatures, degradation of the insulation materials used in the furnaces enhances the decrease of the insulation impedance between the thermometer and the furnace which also causes a systematic temperature measurement error. Two high-temperature standard platinum resistance thermometers have been used to measure these effects in different heat-pipe and three-zone furnaces. One of them was open-circuited by cutting the sensing element end allowing the measurement of the resistance between the two pairs of current-potential leads. Two different setups were used to measure the AC and DC insulation resistances lead-to-lead and thermometer-to-furnace. The first one was a teraohmeter with a high value standard resistor in parallel with the leakage resistance to be measured and the other one an LCR meter to perform the AC measurements at different frequencies. In this article, results for both methods are presented.
Integrated Three-Port DC-DC Converter for Photovoltaic (PV) Battery Stand-alone Systems
Ouyang, Ziwei; Andersen, Michael A. E.
2016-01-01
different single-input single-output (SISO) dc/dc converters would have been used. To reduce the cost and improve the power density of the system, an integrated three-port isolated dc/dc converter is proposed in this paper. It can realize all functions of the energy delivery due to the fluctuation nature......Several power sources such as PV solar arrays and battery are often used to manage the power flow for a photovoltaic (PV) based stand-alone power system due to the fluctuation nature of solar energy resource, and deliver a continuous power to the users in an appropriate form. Traditionally, three...... for PV and battery stand-alone system....
New topology for DC/DC bidirectional converter for hybrid systems in renewable energy
Lopez, Juan Carlos; Ortega, Manuel; Jurado, Francisco
2015-03-01
This article presents a new isolated DC/DC bidirectional converter with soft switching, using a transformer with two voltage taps and two full bridges with insulated-gate bipolar transistors (IGBTs), one on each side of the transformer to be integrated in hybrid systems of renewable energy. A large voltage conversion ratio can be achieved using this converter, in buck and booster modes. Also medium and high DC power can be converted with a good efficiency. Analysis and switching techniques have been reported. To verify the principle of operation, a laboratory prototype of 10 kW has been performed. Experimental results are presented, operating in boost mode. The switching algorithm used has been modelled in MATLAB-Simulink to generate C code. This code has been implemented in a DSP F2812, which has been used to build the prototype.
Ghasemi, N.; Zare, F.; Boora, A.A.;
2012-01-01
modulation and harmonic elimination (HE) methods. Multilevel converters may have a DC link with equal or unequal DC voltages. In this study a new HE technique based on the HE method is proposed for multilevel converters with unequal DC link voltage. The DC link voltage levels are considered as additional......Multilevel converters, because of the benefits they attract in generating high quality output voltage, are used in several applications. Various modulation and control techniques are introduced by several researchers to control the output voltage of the multilevel converters like space vector...... and experimental tests are carried out for a single-phase four-level diode-clamped converter....
Trans-inverse (Tx−1) high step-up DC-DC converter
Siwakoti, Yam Prasad; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
In this paper, a new magnetically coupled single-switch non-isolated dc-dc converter with a high voltage gain is proposed. The new topology utilizes a transformer to boost the output voltage. However, unlike other converter topologies with transformer or coupled magnetics, the voltage gain...... in the proposed topology is increased by reducing the turns ratio of the transformer. Hence the name Trans-inverse (Tx−1) is given to represent the inverse transformer principle of operation of the proposed converter. The new topology draws a continuous current from the source, which is required for many...... renewable sources. Further, the leakage energy of the transformer is recycled and transferred to the load using a passive regenerative snubber circuit. In addition, the new topology has dc-current-blocking capacitors, which avoids saturation in the transformer core. Simulation and experimental results have...
Current Source Converter Based Multi-terminal DC Wind Energy Conversion System
Shixiong FAN; Guangyi LIU; Zhanyong YANG; Weiwei MA; Barry W.WILLIAMS
2013-01-01
A current source converter based multi-terminal direct current (DC) wind energy conversion system (WECS) is proposed.The current source DC/DC converter is adopted to connect a wind turbine to an inverter with maximum power point control.Each turbine is associated with a DC source by parallel-connected to a common DC link.After DC power collection,a current source inverter (CSI) using gate turn-off components is used for the grid connection due to its flexible reactive power control and short circuit protection capabilities.For such a parallel connection configuration,the CSI operates in an input voltage control mode,which maintains the DC link voltage constant.The dynamic responses of combined mechanical and electrical systems are investigated with three different operation cases.Simulation and experimental results demonstrate the feasibility and stability of the current source DC/DC converter based multi-terminal DC WECS.
Switched capacitor DC-DC converter ASICs for the upgraded LHC trackers
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
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.
Switched capacitor DC-DC converter ASICs for the upgraded LHC trackers
Bochenek, M; Faccio, F; Michelis, S
2010-01-01
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
A Nonlinear Digital Control Solution for a DC/DC Power Converter
Zhu, Minshao
2002-01-01
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.
Polenov, Dieter
2010-01-15
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.
Informational model verification of ZVS Buck quasi-resonant DC-DC converter
Vakovsky, Dimiter; Hinov, Nikolay
2016-12-01
The aim of the paper is to create a polymorphic informational model of a ZVS Buck quasi-resonant DC-DC converter for the modeling purposes of the object. For the creation of the model is applied flexible open standards for setting, storing, publishing and exchange of data in distributed information environment. The created model is useful for creation of many and different by type variants with different configuration of the composing elements and different inner model of the examined object.
Five-Level Converter with Low Switching Frequency Applied as DC Voltage Supply
Rasmussen, Tonny Wederberg
1999-01-01
This paper describes the use of a multi-level converter as a DC supply. Equations for the converter will be deduced in the nondissipative case. The equations provide solutions to DC voltage and the angle of converter voltage. In addition the spectrum for the harmonics after the elimination...
Advanced DC-DC converter for power conditioning in hydrogen fuel cell systems
Kovacevic, G.; Tenconi, A.; Bojoi, R. [Department of Electrical Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)
2008-06-15
The fuel cell (FC) generators can produce electric energy directly from hydrogen and oxygen. The DC voltage generated by FC is generally low amplitude and it is not constant, depending on the operating conditions. Furthermore, FC systems have dynamic response that is slower than the transient responses typically requested by the load. For this reason, in many applications the FC generators must be interfaced with other energy/power sources by means of an electronic power converter. An advanced full-bridge (FB) DC-DC converter, which effectively achieves zero-voltage switching and zero-current switching (ZVS-ZCS), is proposed for power-conditioning (PC) in hydrogen FC applications. The operation and features of the converter are analyzed and verified by simulations results. The ZVS-ZCS operation is obtained by means of a simple auxiliary circuit. Introduction of the soft-switching operation in PC unit brings improvements not only from the converter efficiency point of view, but also in terms of increased converter power density. Quantitative analysis of hard and soft-switching operating of the proposed converter is also made, bringing in evidence the benefits of soft-switching operation mode. The proposed converter can be a suitable solution for PC in hydrogen FC systems, especially for the medium to high-power applications. (author)
System Tests with DC-DC Converters for the CMS Silicon Strip Tracker at SLHC
Klein, K; Karpinski, W; Merz, J; Sammet, J
2008-01-01
The delivery of power is considered to be one of the major challenges for the upgrade of the CMS silicon strip tracker for SLHC. The inevitable increase in granularity and complexity of the device is expected to result in a power consumption comparable or even higher than the power consumption of todays' strip tracker. However, the space available for cables will remain the same. In addition, a further increase of the tracker material budget due to cables and cooling is considered inacceptable, as the performance of the CMS detector must not be compromised for the upgrade. Novel powering schemes such as serial powering or usage of DC-DC converters have been proposed to solve the problem. To test the second option, substructures of the current CMS silicon strip tracker have been operated for the first time with off-the-shelf DC-DC buck converters as well as with first prototypes of custom-designed DC-DC converters. The tests are described and the results are discussed.
Ultra-Step-Up DC-DC Converter with Integrated Autotransformer and Coupled Inductor
Siwakoti, Yam Prasad; Blaabjerg, Frede; Loh, Poh Chiang
2016-01-01
This paper introduces a new single-switch nonisolated dc-dc converter with very high voltage transfer ratio and reduced semiconductor voltage stress. The converter utilizes an integrated autotransformer and a coupled inductor on the same core to achieve a high step-up voltage gain without extreme...... to use a low voltage and low RDS-on MOSFET, which reduces the cost, and also the conduction and turn on losses of the switch. The principle of operation and theoretical analysis supported by key simulation and experimental waveforms are presented in details....
Comparison of control schemes for a fuel cell hybrid tramway integrating two dc/dc converters
Fernandez, L.M.; Garcia, P.; Garcia, C.A. [Department of Electrical Engineering, EPS Algeciras, University of Cadiz, Avda. Ramon Puyol, s/n, 11202 Algeciras (Cadiz) (Spain); Torreglosa, J.P.; Jurado, F. [Department of Electrical Engineering, EPS Linares, University of Jaen, C/Alfonso X, n 28. 23700 Linares (Jaen) (Spain)
2010-06-15
This paper describes a comparative study of two control schemes for the energy management system of a hybrid tramway powered by a Polymer Electrolyte Membrane (PEM) Fuel Cell (FC) and an Ni-MH battery. The hybrid system was designed for a real surface tramway of 400 kW. It is composed of a PEM FC system with a unidirectional dc/dc boost converter (FC converter) and a rechargeable Ni-MH battery with a bidirectional dc/dc converter (battery converter), both of which are coupled to a traction dc bus. The PEM FC and Ni-MH battery models were designed from commercially available components. The function of the two control architectures was to effectively distribute the power of the electrical sources. One of these control architectures was a state machine control strategy, based on eight states. The other was a cascade control strategy which was used to validate the results obtained. The simulation results for the real driving cycle of the tramway reflected the optimal performance of the control systems compared in this study. (author)
Performance of a spacecraft DC-DC converter breadboard modified for low temperature operation
Gerber, Scott S.; Stell, Chris; Patterson, Richard; Ray, Biswajit
1996-01-01
A 1OW 3OV/5.OV push-pull dc-dc converter breadboard, designed by the Jet Propulsion Laboratory (JPL) with a +50 C to +5 C operating range for the Cassini space probe, was characterized for lower operating temperatures. The breadboard converter which failed to operate for temperatures below -125 C was then modified to operate at temperatures approaching that of liquid nitrogen (LN2). Associated with this low operating temperature range (greater than -196 C) was a variety of performance problems such as significant change in output voltage, converter switching instability, and failure to restart at temperatures below -154 C. An investigation into these problems yielded additional modifications to the converter which improved low temperature performance even further.
Light weight, high power, high voltage dc/dc converter technologies
Kraus, Robert; Myers, Ira; Baumann, Eric
1990-01-01
Power-conditioning weight reductions by orders of magnitude will be required to enable the megawatt-power-level space systems envisioned by the Strategic Defense Initiative, the Air Force, and NASA. An interagency program has been initiated to develop an 0.1-kg/kW dc/dc converter technology base for these future space applications. Three contractors are in the first phase of a competitive program to develop a megawatt dc/dc converter. Researchers at NASA Lewis Research Center are investigating innovative converter topology control. Three different converter subsystems based on square wave, resonant, and super-resonant topologies are being designed. The components required for the converter designs cover a wide array of technologies. Two different switches, one semiconductor and the other gas, are under development. Issues related to thermal management and material reliability for inductors, transformers, and capacitors are being investigated in order to maximize power density. A brief description of each of the concepts proposed to meet the goals of this program is presented.
Ahteshamul Haque
2016-02-01
Full Text Available The energy crisis concern leads to look for alternate source of energy. Solar energy is considered as most reliable among the all renewable energy sources. Solar PV (Photovoltaic is used to convert solar energy into electric energy. The efficiency of solar PV is very low and its characteristic is nonlinear. To overcome these drawbacks a technique known as maximum power point tracking is used. This algorithm is implemented in the control circuit of DC – DC converter. The objective of this paper is to evaluate the MPPT (Maximum Power Point Tracking with buck DC-DC converter under load varying conditions. The simulation work is done using PSIM simulation software.
Startup Capability of Boost DC/DC Converter%Boost DC/DC的低压启动能力
向乾尹; 冯全源
2011-01-01
An analytical model was proposed to calculate the minimum startup voltage of a boost DC/ DC converter under a constant current load. The factors, such as the current load, the parasitic parameters, the saturation current and on-resistance of the power switch, the switching frequency, and the minimum startup voltage, etc. , which affect the startup capability of the boost DC/DC converter were analyzed with a steady-state analysis method. The model was applied to the design of a boost DC/ DC converter with a 0. 6 jxm CMOS process, and the maximum error of the minimum startup voltage calculated by the proposed model was 4. 5% compared with that by the HSPICE simulator.%为了准确预测Boost DC/DC低压启动能力,采用稳态分析方法,分析了电流负载、寄生参数、功率开关饱和电流及导通阻抗、开关频率、启动电路最低工作电压等因素对Boost DC/DC低压启动能力的影响,提出了预测Boost DC/DC恒流负载下最小启动电压的解析模型.将该模型应用于采用0.6 μm CMOS工艺的Boost DC/DC设计中,模型计算结果相对HSPICE仿真结果的最大误差为4.5%.本模型可推广至恒定电阻负载的情况.
Feste, J.P.
2000-03-01
The DC to DC converters built by the US SynQor company use a dual stage conversion technique. One stage is devoted to regulation and the other to insulation. This technique allows to combine a high efficiency (up to 90%) with small dimensions. Instead of the classical Schottky diodes, a synchronous MOSFET is used for the rectification of the low voltage current. A simple air flow is required for the cooling of these converters. Short paper. (J.S.)
Optimization with System Damping Restoration for Droop Controlled DC-DC Converters
Meng, Lexuan; Dragicevic, Tomislav; Guerrero, Josep M.;
2013-01-01
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...... 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.......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...
A DC-DC Converter with Wide Input Voltage Range for Fuel Cell and Supercapacitor Application
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael Andreas E.
2009-01-01
This paper proposes a novel phase-shift plus duty cycle controlled hybrid bi-directional DC-DC converter based on fuel cells and supercapacitors. The described converter employs two high frequency transformers to couple the half-bridge and full-bridge circuits together in the primary side...... and voltage doubler circuit in secondary side. Boost type converter can limit the output ripple current of the fuel cells; hybrid full-bridge structure can change operating modes according to the different input voltage; phase-shift with duty cycle control scheme is utilized to control the bidirectional power...... flow flexibly. All the switches can turn on under zero-voltage-switching condition (ZVS). The operating principles of the converter are described in details, and the experimental results based on the prototype controlled by DSP are presented to verify the validity of the analysis and design....
High efficiency interleaved bi-directional ZVS DC-DC converter
Zafarullah Khan, M.; Mohsin Naveed, M.; Akbar Hussain, D. M.
2013-06-01
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.
Research on transient hysteresis current control strategy of DC-DC converter
Zhang, Ting; Wang, Zu-liang; Zhao, Yu-kai
2017-01-01
In order to improve the dynamic performance of DC-DC converter, transient hysteresis current control strategy is proposed which is based on parallel computing and combinational logic. By making a comparison between the real-time inductor current and the threshold inductor current, the switch is controlled more accurately. Under the Matlab/Simulink environment, the process of the Buck-Boost converter was simulated. The simulation results show that the transient hysteresis current control strategy can effectively overcome the disadvantages when load changes or input voltage disturbance occurs, it posses high load regulation and short dynamic response time, and it verifies the feasibility of the proposed strategy.
Analysis and Experimental Study of Proportional-Integral Sliding Mode Control for DC/DC Converter
ZHANG Li; QIU Shui-sheng
2005-01-01
DC/DC converter using the proportional-integral (PI) sliding mode control (SMC) scheme is investigated, including the selection of the switching surface, the proof of the reaching condition and the existence condition of sliding motion. The sliding regime and the local stability are given. The implementation of the PI SMC is simpler than other SMC schemes and the steady-state error is eliminated. A prototype based on Buck converter is built up. The experimental results show that the dynamic performance and robustness to the parameter variations and external disturbances are improved.
Finite-time control of DC-DC buck converters via integral terminal sliding modes
Chiu, Chian-Song; Shen, Chih-Teng
2012-05-01
This article presents novel terminal sliding modes for finite-time output tracking control of DC-DC buck converters. Instead of using traditional singular terminal sliding mode, two integral terminal sliding modes are introduced for robust output voltage tracking of uncertain buck converters. Different from traditional sliding mode control (SMC), the proposed controller assures finite convergence time for the tracking error and integral tracking error. Furthermore, the singular problem in traditional terminal SMC is removed from this article. When considering worse modelling, adaptive integral terminal SMC is derived to guarantee finite-time convergence under more relaxed stability conditions. In addition, several experiments show better start-up performance and robustness.
Magnusson, N., E-mail: niklas.magnusson@sintef.no [SINTEF Energy Research, NO-7465 Trondheim (Norway); Abrahamsen, A.B. [DTU Wind Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Liu, D. [Electrical Power Processing Group, TU Delft, Mekelweg 4, NL-2628 CD Delft (Netherlands); Runde, M. [SINTEF Energy Research, NO-7465 Trondheim (Norway); Polinder, H. [Electrical Power Processing Group, TU Delft, Mekelweg 4, NL-2628 CD Delft (Netherlands)
2014-11-15
Highlights: • A method for calculating hysteresis losses in the low AC – high DC magnetic field and transport current range has been shown. • The method can be used in the design of wind turbine generators for calculating the losses in the generator DC rotor. • First estimates indicate tolerable current ripple in the 0.1% range for a 4 T DC MgB{sub 2} generator rotor coil. - Abstract: MgB{sub 2} superconductors are considered for generator field coils for direct drive wind turbine generators. In such coils, the losses generated by AC magnetic fields may generate excessive local heating and add to the thermal load, which must be removed by the cooling system. These losses must be evaluated in the design of the generator to ensure a sufficient overall efficiency. A major loss component is the hysteresis losses in the superconductor itself. In the high DC – low AC current and magnetic field region experimental results still lack for MgB{sub 2} conductors. In this article we reason towards a simplified theoretical treatment of the hysteresis losses based on available models in the literature with the aim of setting the basis for estimation of the allowable magnetic fields and current ripples in superconducting generator coils intended for large wind turbine direct drive generators. The resulting equations use the DC in-field critical current, the geometry of the superconductor and the magnitude of the AC magnetic field component as parameters. This simplified approach can be valuable in the design of MgB{sub 2} DC coils in the 1–4 T range with low AC magnetic field and current ripples.
A 10 kW dc-dc converter using IGBTs with active snubbers. [Insulated Gate Bipolar Transistor
Masserant, Brian J.; Shriver, Jeffrey L.; Stuart, Thomas A.
1993-01-01
This full bridge dc-dc converter employs zero voltage switching (ZVS) on one leg and zero current switching (ZCS) on the other. This technique produces exceptionally low IGBT switching losses through the use of an active snubber that recycles energy back to the source. Experimental results are presented for a 10 kW, 20 kHz converter.
A low noise high efficiency buck DC-DC converter with sigma-delta modulation
Cai Shujiang; Pi Changming; Yan Wei; Li Wenhong, E-mail: wenhongli@fudan.edu.cn [State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 201203 (China)
2011-07-15
Some research efforts to improve the efficiency and noise performance of buck DC-DC converters are explored. A carefully designed power MOSFET driver, including a dead time controller, discontinuous current mode (DCM) controller and gate width controller, is proposed to improve efficiency. Instead of PWM modulation, sigma-delta modulation is introduced into the feedback loop of the converter to move out the clock-referred harmonic spike. The proposed converter has been designed and fabricated by a 0.35 {mu}m CMOS process. Measured results show that the peak efficiency of the converter can reach 93% and sigma-delta modulation suppresses the harmonic spike by 30 dB over PWM modulation. (semiconductor integrated circuits)
Dhananjay Choudhary
2014-08-01
Full Text Available The two basic topologies of switch mode DC-DC converters (Buck and Boost are analyzed with a view of their use in PV (photovoltaic systems, as the photovoltaic generator exhibits non-linear characteristics due to the change in environmental condition and load variation. As the efficiency of PV panels is low it becomes mandatory to extract maximum power from the PV panel at a given period of time. Several MPPT algorithms with different types of converters are being proposed for extracting maximum power from the PV panel. It is found that the nature of load plays an important role in the choice of topology. This paper investigates the implementation issues of Incremental Conductance method with Buck and Boost Converters. Mathematical analysis and desirable steady-state operating point of the converters are derived to give satisfactory maximum power point tracking operation.
High-Voltage 1-kW dc/dc Converter Developed for Low-Temperature Operation
Patterson, Richard L.
1998-01-01
Recently, Lewis developed and demonstrated a high-voltage, 1-kW dc/dc converter that operates from room temperature to -184 C. A power supply designed for use in a NASA ion beam propulsion system was utilized as a starting point for the design of a low- (wide-) temperature dc/dc converter. For safety, we decided to halve the output voltage and power level, so the converter was designed for an 80-Vdc input and a 550-Vdc output at 1 kW.
Ouyang, Ziwei; Andersen, Michael A. E.; Thomsen, Ole Cornelius
2012-01-01
A common limitation of power coupling effect in some known multiple-input dc-dc converters has been addressed in many literatures. In order to overcome this limitation, a new concept for decoupling the primary windings in the integrated multiple-winding transformers based on 3-dimensional (3D....... In order to verify the feasibility of the FQIT in multiple-input converter, a dual-input isolated boost dc-dc converter employing with the FQIT is designed and tested. The results have excellently demonstrated that the two input power stages can be operated independently and the correctness of all...
Low Temperature Performance of High Power Density DC/DC Converter Modules
Elbuluk, Malik E.; Hammond, Ahmad; Gerber, Scott; Patterson, Richard L.; Overton, Eric
2001-01-01
In this paper, two second-generation high power density DC/DC converter modules have been evaluated at low operating temperatures. The power rating of one converter (Module 1) was specified at 150 W with an input voltage range of 36 to 75 V and output voltage of 12 V. The other converter (Module 2) was specified at 100 W with the same input voltage range and an output voltage of 3.3 V. The converter modules were evaluated in terms of their performance as a function of operating temperature in the range of 25 to -140 C. The experimental procedures along with the experimental data obtained are presented and discussed in this paper.
Analysis of Discontinuity Induced Bifurcations in a Dual Input DC-DC Converter
Giaouris, Damian; Banerjee, Soumitro; Mandal, Kuntal; Al-Hindawi, Mohammed M.; Abusorrah, Abdullah; Al-Turki, Yusuf; El Aroudi, Abdelali
DC-DC power converters with multiple inputs and a single output are used in numerous applications where multiple sources, e.g. two or more renewable energy sources and/or a battery, feed a single load. In this work, a classical boost converter topology with two input branches connected to two different sources is chosen, with each branch independently being controlled by a separate peak current mode controller. We demonstrate for the first time that even though this converter is similar to other well known topologies that have been studied before, it exhibits many complex nonlinear behaviors that are not found in any other standard PWM controlled power converter. The system undergoes period incrementing cascade as a parameter is varied, with discontinuous hard transitions between consecutive periodicities. We show that the system can be described by a discontinuous map, which explains the observed bifurcation phenomena. The results have been experimentally validated.
一种单位功率因数单相AC/DC变换器的研究%Investigation on a Single-phase AC/DC Converter with Unity Power Factor
杨喜军; 陈红平; 叶芃生
2004-01-01
根据传统升压式AC/DC变换器的功率因数校正原理,讨论了两种升压电感置于整流桥前的单相AC/DC变换器,在对其进行仿真分析之后认为,它们的控制原理可以保持不变,其控制电路也可通过适当改进传统单相AC/DC变换器的控制电路而得到,而且因结构紧凑而便于功率集成.最后给予了物理实现,功率达到2kW以上,仿真结果与实验结果验证了理论分析的正确性.
Zheng Wang
2016-01-01
Full Text Available Three-port isolated (TPI bidirectional DC/DC converters have three energy ports and offer advantages of large voltage gain, galvanic isolation ability and high power density. For this reason this kind of converters are suitable to connect different energy sources and loads in electric and hybrid vehicles. The purpose of this paper is to propose chaotic modulation and the related control scheme for TPI bidirectional DC/DC converters, in such a way that the switching harmonic peaks can be suppressed in spectrum and the conducted electromagnetic interference (EMI is reduced. Two chaotic modulation strategies, namely the continuously chaotic modulation and the discretely chaotic modulation are presented. These two chaotic modulation strategies are applied for TPI bidirectional DC/DC converters with shifted-phase angle based control and phase-shifted PWM control. Both simulation and experiments are given to verify the validity of the proposed chaotic modulation-based control schemes.
A Reduced-Part, Triple-Voltage DC-DC Converter for EV/HEV Power Management
Su, Gui-Jia [ORNL; Tang, Lixin [ORNL
2009-01-01
Electrical power systems in future hybrid and fuel cell vehicles may consist of three voltage nets: 14 V, 42 V, and high voltage (>200 V) buses. A soft-switched, bidirectional dc-dc converter that uses only four switches was proposed for interconnecting the three nets. This paper presents a reduced-part dc-dc converter, which decreases the converter cost while retaining all the favorable features of the original topology. Experimental data are included to verify a simple power flow control scheme.
ASIC and FPGA based DPWM architectures for single-phase and single-output DC-DC converter: a review
Chander, Subhash; Agarwal, Pramod; Gupta, Indra
2013-12-01
Pulse width modulation (PWM) has been widely used in power converter control. This paper presents a review of architectures of the Digital Pulse Width Modulators (DPWM) targeting digital control of switching DC-DC converters. An attempt is made to review the reported architectures with emphasis on the ASIC and FPGA implementations in single phase and single-output DC-DC converters. Recent architectures using FPGA's advanced resources for achieving the resolution higher than classical methods have also been discussed. The merits and demerits of different architectures, and their relative comparative performance, are also presented. The Authors intention is to uncover the groundwork and the related references through this review for the benefit of readers and researchers targeting different DPWM architectures for the DC-DC converters.
Sanjeevikumar, Padmanaban; Grandi, Gabriele; Wheeler, Patrick
2015-01-01
This paper presents the novel topology of Photo Voltaic (PV) power generation system with simple Maximum Power Point Tracking (MPPT) algorithm in voltage operating mode. Power circuit consists of high output voltage DC-DC boost converter which maximizes the output of PV panel. Usually traditional...... of DC-DC converters for PV integration. Hence, to overcome these difficulties this paper investigates a DC-DC boost converter together with the additional parasitic component within the circuit to provide high output voltages for maximizing the PV power generation. The proposed power system circuit...... substantially improves the high output-voltage by a simple MPPT closed loop proportional-integral (P-I) controller, and requires only two sensor for feedback needs. The complete numerical model of the converter circuit along with PV MPPT algorithm is developed in numerical simulation (Matlab/Simulink) software...
王建全; 杨兴华; 张峦国; 杨喜军
2006-01-01
将谐振电抗器和磁能恢复开关引入到单相AC-DC变换器中,设计了一种新颖的混合单相AC-DC变换器.在理论分析谐振电抗器和磁能恢复开关单独在单相功率因数校正器(PFC)应用中的优点和不足的基础上,提出了一种结合两者长处的功率因数校正方法,能够获得更高输入功率因数(PF)和更高输出直流电压.并利用仿真软件ORCAD 10.5建立了完整的单相AC-DC变换器-逆变器仿真电路,对上述3种情况进行了FFT和参数扫描等仿真分析.结果说明了所提出的方案是可行的和低成本的,能够支持较大的输出功率,可以作为变频家用电器等的前级单相AC-DC变换器.
Digital Implementation of Two Inductor Boost Converter Fed DC Drive
G. Kishor
2011-01-01
Full Text Available The study deals w ith simulation and implementation of two inductor boost converter fed DC drive. The two inductor boost converter fed DC drive is simulated and implemented. The circuit has advantages like higher output voltage and improved power factor. The laboratory model is implemented and the experimental results are obtained. The experimental results were compared w ith the simulation results.
Relations between ac-dc components and optical path length in photoplethysmography
Lee, Chungkeun; Sik Shin, Hang; Lee, Myoungho
2011-07-01
Photoplethysmography is used in various areas such as vital sign measurement, vascular characteristics analysis, and autonomic nervous system assessment. Photoplethysmographic signals are composed of ac and dc, but it is difficult to find research about the interaction of photoplethysmographic components. This study suggested a model equation combining two Lambert-Beer equations at the onset and peak points of photoplethysmography to evaluate ac characteristics, and verified the model equation through simulation and experiment. In the suggested equation, ac was dependent on dc and optical path length. In the simulation, dc was inversely proportionate to ac sensitivity (slope), and ac and optical path length were proportionate. When dc increased from 10% to 90%, stabilized ac decreased from 1 to 0.89 +/- 0.21, and when optical path length increased from 10% to 90%, stabilized ac increased from 1 to 1.53 +/- 0.40.
A.S. Oshaba
2013-05-01
Full Text Available This study presents an approach for the speed control of a permanent magnet DC motor drive via Pulse Width Modulation (PWM technique and a DC/DC converter. The Particle Swarm Optimization (PSO technique is used to minimize a time domain objective function and obtain the optimal controller parameters. The performance of the proposed technique has been evaluated using various types of disturbances including load torque variations. Simulation results illustrate clearly the robustness of the controller and validity of the design technique for controlling the speed of permanent magnet motors.
A Review of Galvanically Isolated Impedance-Source DC–DC Converters
Chub, Andrii; Vinnikov, Dmitri; Blaabjerg, Frede;
2016-01-01
Impedance-source converters, an emerging technology in electric energy conversion, overcome limitations of conventional solutions by the use of specific impedance-source networks. Focus of this paper is on the topologies of galvanically isolated impedance-source dc-dc converters. These converters...... isolated dc-dc converters according to the element that transfers energy from the input to the output: a transformer, a coupled inductor, or their combination. This classification reveals advantages and disadvantages, as well as a wide space for further research. This paper also outlines the most promising...
A Stable Control Strategy for Input-Series Output-Series Connected Boost half Bridge DC-DC Converter
Shahnawaz Farhan Khahro
2013-07-01
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.
Liu, Changjin; Xu, Dehong; Zhu, Nan;
2013-01-01
Unbalanced grid voltage causes a large second-order harmonic current in the dc-link capacitors as well as dc-voltage fluctuation, which potentially will degrade the lifespan and reliability of the capacitors in voltage source converters. This paper proposes a novel dc-capacitor current control...... method for a grid-side converter (GSC) to eliminate the negative impact of unbalanced grid voltage on the dc-capacitors. In this method, a dc-capacitor current control loop, where a negative-sequence resonant controller is used to increase the loop gain, is added to the conventional GSC current control...... loop. The rejection capability to the unbalanced grid voltage and the stability of the proposed control system are discussed. The second-order harmonic current in the dc capacitor as well as dc-voltage fluctuation is very well eliminated. Hence, the dc capacitors will be more reliable under unbalanced...
DC-DC converters for the upgrades of the CMS tracker
Sammet, Jan; Feld, Lutz; Karpinski, Waclaw; Klein, Katja; Merz, Jennifer; Wehner, Jakob; Wlochal, Michael [RWTH Aachen University, I. Physikalisches Instiut B (Germany)
2011-07-01
Within the present decade, it is foreseen to gradually increase the instantaneous luminosity of the LHC to 1-2.10{sup 34} cm{sup -2}s{sup -1}. Around 2020, it is intended to increase the luminosity further, to about 5.10{sup 34} cm{sup -2}s{sup -1}. To ensure and improve its physics performance, CMS is going to exchange its pixel detector around 2016. Four years later the complete tracker is going to be replaced by a new development. The use of DC-DC converters is foreseen for both of these upgrades. Radiation tolerant converters developed by working groups at CERN and Aachen match the requirements of the new pixel detector already. However, further work is required to integrate the converters on system level and to ensure their save and reliable operation. The status of this work is presented. Building a new tracking detector equipped with converters, raises several additional challenges. In particular the noise performance of the converters and their efficiency at large conversion ratios still has to be improved. The coil, used by the converters to buffer energy, has a significant impact on both of these issues. Effort has been put into the optimization of converter coils, as well as into the exploration and minimization of noise radiated by the coils. The talk gives a summary of the results of this work.
Wester, Gene W. (Inventor)
1980-01-01
A unity power factor converter capable of effecting either inversion (dc-to-dc) or rectification (ac-to-dc), and capable of providing bilateral power control from a DC source (or load) through an AC transmission line to a DC load (or source) for power flow in either direction, is comprised of comparators for comparing the AC current i with an AC signal i.sub.ref (or its phase inversion) derived from the AC ports to generate control signals to operate a switch control circuit for high speed switching to shape the AC current waveform to a sine waveform, and synchronize it in phase and frequency with the AC voltage at the AC ports, by selectively switching the connections to a series inductor as required to increase or decrease the current i.
Control and modulation for loss minimization for dc/dc converters in wind farm
Dincan, Catalin Gabriel; Kjær, Philip Carne
2016-01-01
For a DC wind turbine, a single phase series-resonant converter for unidirectional power is studied. This paper aims to identify and compare impact on electrical losses and component ratings from the choice of three candidate control strategies. The evaluation is purely based on circuit simulatio...
Sona P
2014-02-01
Full Text Available A high efficiency interleaved ZVS active clamped current fed dc-dc converter is proposed in this paper specially used for fuel cell applications. As the fuel cell output is very low we are in need of a step up dc-dc converter. Here a current fed dc-dc converter is used. Two current fed dc-dc converters are interleaved by connecting their inputs in parallel and outputs in series. With this proposed methodology input current ripples in the fuel cell stacks can be reduced and a regulated output voltage ripples can be obtained. The active clamping circuit used in this model absorbs the turn off voltage spikes hence low voltage devices with low on state resistance can be used.Voltage doubler circuits will give double the output voltage than normal with smaller transformer turns ratio and flexibility. The proposed method is simulated in MATLAB for verifying the accuracy of the proposed design.
Modular Power System Configured with Standard Product Hybrid DC-DC Converters Project
National Aeronautics and Space Administration — VPT proposes an innovative concept whereby complex NASA space power electronic systems can be configured using a small number of qualified hybrid DC-DC converter and...
Decentralized Nonlinear Controller Based SiC Parallel DC-DC Converter Project
National Aeronautics and Space Administration — This proposal is aimed at demonstrating the feasibility of a Decentralized Control based SiC Parallel DC-DC Converter Unit (DDCU) with targeted application for...
Compact DC-DC Converter for Pocket Micro-Controller Systems
无
1996-01-01
Novel compact DC-C converters for pocket micro-controller systems are discussed in the paper,which are based on switched capcotprs and inductorless,consequently are more suitable for being hybridized.The new converters enable the pocket microcontroller system to be powered by only one+12V source,while+5V and -12V are converted from the +12V source.The basic principle,voltage ratio,efficiency and ripples are analysed.Experiment and SPICE simulation are also given,which show positive results.
Load Dump Analysis in a 42/14V DC-DC Converter for Automotive Applications
Mohamed Abdualla Shrud
2013-07-01
Full Text Available The paper presents a model for a dc-dc centralised based architecture using Matlab/Simulink for load dump analysis. As the electrical load varies for various driving conditions such as day or night, summer or winter; and city or country side, the analysis of load change is a very important parameter for system behaviour. In order to study the 42V power generation dynamic performance under load variations, step change in loads have been investigated. A detailed mathematical model for a 3-phase, 4 kW and 42V Lundell alternator average electrical equivalent circuit along with the DC/DC converter based architectures for dual-voltage systems has been covered in previous publications. Aspects of the steady-state output current capabilities, transient behaviour due to load dump on the 14/42V buses and the behaviour of the system model under different loads are assessed and results discussed. The performance of the 42V Lundell alternator with the interleaved six-phase buck dc-to-dc converter system is modelled using Simulink software to assess the effectiveness of the model and its transient behaviour. The simulated results are presented for the transient characteristics of the system for load dumps.
Self-Stable Chaos Control of dc-dc Converter
LU Wei-Guo; ZHOU Luo-Wei; WU Jun-Ke
2009-01-01
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.
A Compact, Soft-Switching DC-DC Converter for Electric Propulsion
Button, Robert; Redilla, Jack; Ayyanar, Raja
2003-01-01
A hybrid, soft-switching, DC-DC converter has been developed with superior soft switching characteristics, high efficiency, and low electro-magnetic interference. This hybrid topology is comprised of an uncontrolled bridge operating at full pulse-width, and a controlled section operating as a conventional phase modulated converter. The unique topology is able to maintain zero voltage switching down to no load operating conditions. A breadboard prototype was developed and tested to demonstrate the benefits of the topology. Improvements were then made to reduce the size of passive components and increase efficiency in preparation for packaging. A packaged prototype was then designed and built, and several innovative packaging techniques are presented. Performance test data is presented that reveals deficiencies in the design of the power transformer. A simple redesign of the transformer windings eliminated the deficiency. Future plans to improve the converter and packaging design are presented along with several conclusions.
Large step-down DC-DC converters with reduced current stress
Ismail, Esam H. [Department of Electrical Engineering, College of Technological Studies, P.O. Box 35007, 36051 Al-Shaab (Kuwait)
2009-02-15
In this paper, several DC-DC converters with large voltage step-down ratios are introduced. A simple modification in the output section of the conventional buck and quadratic converters can effectively extend the duty-cycle range. Only two additional components (an inductor and diode) are necessary for extending the duty-cycle range. The topologies presented in this paper show an improvement in the duty-cycle (about 40%) over the conventional buck and quadratic converters. Consequently, they are well suited for extreme step-down voltage conversion ratio applications. With extended duty-cycle, the current stress on all components is reduced, leading to a significant improvement of the system losses. The principle of operation, theoretical analysis, and comparison of circuit performances with other step-down converters is discussed regarding voltage and current stress. Experimental results of one prototype rated 40-W and operating at 100 kHz are provided in this paper to verify the performance of this new family of converters. The efficiency of the proposed converters is higher than the quadratic converters. (author)
Ma, Siyuan; Wang, Haoran; Tang, Junchaojie;
2016-01-01
-link capacitor capacitance can be decreased. However, few research is about the effect of DC side and AC side decoupling on the DC-link capacitor reliability considering its electro-thermal stresses. This paper presents a quantitative analysis on the lifetime of capacitors with power decoupling circuits......In single-phase inverters, DC-link capacitors are installed at the DC-link to buffer the ripple power between the AC side and DC side. Active decoupling methods introduce additional circuits at the DC side or AC side to partially or fully supply the ripple power. So that the demanded DC...
Design of the DC-DC power stage of the capacitor charger for MAXIDISCAP power converters
Cravero, Jean-Marc
2013-01-01
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.
Systematic design approach of fuzzy PID stabilizer for DC-DC converters
Guesmi, K.; Essounbouli, N.; Hamzaoui, A. [CReSTIC, IUT de Troyes 09, rue de Quebec BP. 396, 10026 Troyes (France)
2008-10-15
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. (author)
Design of a total-dose radiation hardened monolithic CMOS DC-DC boost converter
Liu Zhi; Yu Hongbo; Liu Youbao [Xi' an Institute of Microelectronics Technology, Xi' an 710054 (China); Ning Hongying, E-mail: liuzhi6048@126.com [Xi' an University of Technology, Xi' an 710048 (China)
2011-07-15
This paper presents the design and implementation of a monolithic CMOS DC-DC boost converter that is hardened for total dose radiation. In order to improve its radiation tolerant abilities, circuit-level and device-level RHBD (radiation-hardening by design) techniques were employed. Adaptive slope compensation was used to improve the inherent instability. The H-gate MOS transistors, annular gate MOS transistors and guard rings were applied to reduce the impact of total ionizing dose. A boost converter was fabricated by a standard commercial 0.35 {mu}m CMOS process. The hardened design converter can work properly in a wide range of total dose radiation environments, with increasing total dose radiation. The efficiency is not as strongly affected by the total dose radiation and so does the leakage performance. (semiconductor integrated circuits)
Performance of a Voltage Step-Up/Step-Down Transformerless DC/DC Converter: Analytical Model
Suskis, P.; Rankis, I.
2012-01-01
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.
A High Voltage-lift Efficient Isolated Full Bridge DC-DC Converter
A. Gopi
2014-05-01
Full Text Available The aim of this study is to propose a high voltage lift isolated full bridge dc-dc converter. The proposed converter consists of an isolation transformer a low turn ratio to obtain high step up voltage gain. The secondary of the transformer connected with two boosting capacitors which connects parallel when power switches switch on period and discharged in series during the switch off period. In addition full bridge converter on primary side consists of clamping diode and capacitor, leakage energy is recycled there by improving conversion efficiency. The proposed circuits simulated using PSIM software form input voltage of 48V, an output of 410 V obtained. These results and operations experimented and validated by implementing in hardware model at 20/40 Vdc, 20 Watts.
Stability analysis of a high-step-Up DC grid-connected two-stage boost DC-DC converter
El Aroudi A.
2014-01-01
Full Text Available High conversion ratio switching converters are used whenever there is a need to step-up dc source voltage level to a much higher output dc voltage level such as in photovoltaic systems, telecommunications and in some medical applications. A simple solution for achieving this high conversion ratio is by cascading different stages of dc-dc boost converters. The individual converters in such a cascaded system are usually designed separately applying classical design criteria. However these criteria may not be applicable for the complete cascaded system . This paper first presents a glimpse on the bifurcation behavior that a cascade connection of two boost converters can exhibit. It is shown that the desired periodic orbit can undergo period doubling leading to subharmonic oscillations and chaotic regimes. Then, in order to simplify the analysis the second stage is considered as constant current sink and design-oriented analysis is carried out to obtain stability boundaries in the parameter space by taking into account slope interactions between the state variables in the two-different stages.
DC-DC buck converters for the CMS Tracker upgrade at SLHC
Feld, L; Jussen, R; Karpinski, W; Klein, K; Sammet, J, E-mail: Katja.Klein@cern.ch [1. Physikalisches Institut B, RWTH Aachen University, Sommerfeldstrasse 14, 52074 Aachen (Germany)
2011-01-15
The CMS experiment at the Large Hadron Collider (LHC) at CERN, Geneva, is planning major upgrades of its current pixel and strip detectors for the LHC luminosity upgrade, known as the SLHC. Due to the larger channel count and - in case of the strip tracker - increased functionality, the powering scheme adopted today, namely parallel powering of several detector modules, has to be abandoned. Instead, a powering scheme based on the DC-DC conversion technique is foreseen, which would lead to lower power losses in the supply cables, and would allow to reduce the material budget of cables and associated electronic boards in the sensitive detector volume. This paper deals with the development, characterisation and optimisation of DC-DC buck converter prototypes for the upgrades of the CMS pixel and strip detectors at the SLHC.
Harmonic analysis of AC/DC systems based on phase-domain multi-port network approach
Gutierrez, O.; Fuerte-Esquivel, C.R. [Universidad Michoacana de San Nicolas de Hidalgo, Facultad de Ingenieria Electrica, Division de Estudios de Posgrado, Cuidad Universitaria, 58030 Morelia, Michoacan (Mexico); Rubio, J.A.; Guardado, J.L. [Instituto Tecnologico de Morelia, Av. Tecnologico 1500, 58120 Morelia, Michoacan (Mexico)
2008-10-15
This paper describes a phase-domain frequency domain technique to the harmonic analysis of a three-phase AC/DC system. The methodology is based on the harmonic multi-port network concept, expressed in terms of an ABCD parameter matrix which links voltage and current harmonics of different orders on both sides of the converter. Since the commutation angles are unknown, the harmonic interactions are computed by a sequential solution of the AC/DC system state variables, related by the ABCD matrix, and the updating of the commutation periods. A set of analytical equations has been derived to compute commutation times taking place in the converter. Test results are presented which demonstrate the effectiveness of the proposed methodology to assess harmonic interactions on both balanced and unbalanced operating conditions. The results are validated to those obtained by a time domain simulation. (author)
Bogimi Sirisha
2012-03-01
Full Text Available In this paper, a three-phase two leg neutral point clamped (NPC converter is presented for power factor correction and dc-link voltage regulation. The adopted converter has simpler circuit configuration and less number of power switches compared to three-level PWM converter. In this circuit configuration, only eight power switches and four clamping diodes with voltage stress of half the dc bus voltage are used. A simplified space vector pulse width modulation scheme (SVPWM is also adopted to track the line current commands. A reference voltage vector is generated on the ac terminal for drawing the sinusoidal line currents with unity power factor. This algorithm reduces the time required to calculate the switching time durations of voltage vectors. The simulation results have been presented to verify the validity and effectiveness of the proposed control strategy.
Single phase system control and modeling of bidirectional AC/DC converters%双向AC/DC变换器的单相系统控制与建模
张加胜; 李浩光
2008-01-01
基于单相双向AC/DC变换器的状态空间平均模型及输出波形特点,提出一种适用于建立系统控制模型的"平均值分离法"和"半周期平均法",通过解析分析和线性化处理,推导出其有关交流侧电流幅度和直流侧输出电压的传递函数模型和离散化控制模型,并进行稳态理论分析,为系统设计提供依据.通过样机实验波形证实了所得控制模型及理论分析结果的正确性与可行性.
Load adaptive start-up scheme for synchronous boost DC-DC converter
Guoding, Dai; Wenliang, Xiu; Yuezhi, Liu; Yawei, Qi; Zuqi, Dong
2016-10-01
This paper presents a load adaptive soft-start scheme through which the inductor current of the synchronous boost DC-DC converter can trace the load current at the start-up stage. This scheme effectively eliminates the inrush-current and over-shoot voltage and improves the load capability of the converter. According to the output voltage, the start-up process is divided into three phases and at each phase the inductor current is limited to match the load. In the pre-charge phase, a step-increasing constant current gives a smooth rise of the output voltage which avoids inrush current and ensures the converter successfully starts up at different load situations. An additional ring oscillator operation phase enables the converter to start up as low as 1.4 V. When the converter enters into the system loop soft-start phase, an output voltage and inductor current detection methods make the transition of the phases smooth and the inductor current and output voltage rise steadily. Effective protection circuits such as short-circuit protection, current limit circuit and over-temperature protection circuit are designed to guarantee the safety and reliability of the chip during the start-up process. The proposed start-up circuit is implemented in a synchronous boost DC-DC converter based on TSMC 0.35 μm CMOS process with an input voltage range 1.4-4.2 V, and a steady output voltage 5 V, and the switching frequency is 1 MHz. Simulation results show that inrush current and overshoot voltage are suppressed with a load range from 0-2.1 A, and inductor current is as low as 259 mA when the output shorts to the ground.
Park, Jungyong; Kim, Shiho
2012-06-01
An analog maximum power point tracking (MPPT) circuit for a thermoelectric generator (TEG) is proposed. We show that the peak point of the voltage conversion gain of a boost DC-DC converter with an input voltage source having an internal resistor is the maximum power point of the TEG. The key characteristic of the proposed MPPT controller is that the duty ratio of the input clock pulse to the boost DC-DC converter shifts toward the maximum power point of the TEG by seeking the peak gain point of the boost DC-DC converters. The proposed MPPT technique provides a simple and useful analog MPPT solution, without employing digital microcontroller units.
Vrana, Til Kristian; Zeni, Lorenzo; Fosso, Olav Bjarte
A new control method for large meshed HVDC grids has been developed, which helps to keep the active power balance at the AC and the DC side. The method definition is kept wide, leaving the possibility for control parameter optimisation. Other known control methods can be seen as specific examples...... the band, but not set to zero as with a regular dead-band. It operates with a minimum of required communication. New converters can be added to the system without changing the control of the other individual converters. It is well suited to achieve high reliability standards due to the distributed control...
Control of Parallel DC/DC Converters in DC Microgrid%直流微网中平行DC/DC变换器的控制
叶友泉; 杨冠鲁
2016-01-01
提出以多墙体光伏为研究对象的光伏直流微网系统。将在逆变器并联控制中广泛使用的下垂控制策略应用到平行DC/DC变换器的控制中，与电压、电流环构成三闭环控制，从而抑制平行DC/DC变换器之间的环流。通过Simulink 仿真分析，该方法能够实现直流母线电压的稳定及有效抑制各平行DC/DC变换器之间的环流。最后，在实验室搭建实验平台，验证该控制策略的可行性。%This article proposes a photovoltaic ( PV) DC microgrid system which employs multi-wall PV. In the DC microgrid, the droop control strategy widely used in parallel control of inverter is adopted for the control of parallel DC/DC converters, forming a triple-loop control together with voltage and current loops, which restrains the loop current between parallel DC/DC converters. Simulink simulation shows that, stable DC bus voltage and effective control over the loop current among parallel DC / DC converters can be achieved by this way. In the end, an experimental platform is built in the lab to verify the feasibility of this control strategy.
Design of current source DC/DC converter and inverter for 2kW fuel cell application
Andreiciks, A.; Steiks, I.; Krievs, O.
2013-01-01
of a DC/DC converter and an inverter. In this paper a detailed simulation study of such interfacing converter system comprising a double inductor push-pull step-up DC/DC converter and a cascaded H-bridge inverter has been carried out and further confirmed with experimental results. The power converter...
A Two-stage DC-DC Converter for the Fuel Cell-Supercapacitor Hybrid System
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.
2009-01-01
A wide input range multi-stage converter is proposed with the fuel cells and supercapacitors as a hybrid system. The front-end two-phase boost converter is used to optimize the output power and to reduce the current ripple of fuel cells. The supercapacitor power module is connected by push-pull-f...... and designed. A 1kW prototype controlled by TMS320F2808 DSP is built in the lab. Simulation and experimental results confirm the feasibility of the proposed two stage dc-dc converter system.......A wide input range multi-stage converter is proposed with the fuel cells and supercapacitors as a hybrid system. The front-end two-phase boost converter is used to optimize the output power and to reduce the current ripple of fuel cells. The supercapacitor power module is connected by push......-pull-forward half bridge (PPFHB) converter with coupled inductors in the second stage to handle the slow transient response of the fuel cells and realize the bidirectional power flow control. Moreover, this cascaded structure simplifies the power management. The control strategy for the whole system is analyzed...
Time delay control for fuel cells with bidirectional DC/DC converter and battery
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
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)
A Novel Dual-input Isolated Current-Fed DC-DC Converter for Renewable Energy System
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.
2010-01-01
In this paper, a novel isolated current-fed DC-DC converter (boost-type) with two input power sources based on multi-transformer structure, which is suitable for fuel cells and super-capacitors hybrid energy system, is proposed and designed. With particular transformer windings connection strategy....... Furthermore, the method to increase the number of input ports, the magnetic integration structure, and ground loop decoupling are discussed. Experimental results from the lab prototype converter with two DC voltage sources verify the validity of the theoretical analysis and design of the converter....
Advanced DC/AC inverters applications in renewable energy
Luo, Fang Lin
2013-01-01
DC/AC inversion technology is of vital importance for industrial applications, including electrical vehicles and renewable energy systems, which require a large number of inverters. In recent years, inversion technology has developed rapidly, with new topologies improving the power factor and increasing power efficiency. Proposing many novel approaches, Advanced DC/AC Inverters: Applications in Renewable Energy describes advanced DC/AC inverters that can be used for renewable energy systems. The book introduces more than 100 topologies of advanced inverters originally developed by the authors,
Design of a High Efficiency Boost DC-DC Converter
GAO Jing; YAO Suying; XU Jiangtao; SHI Zaifeng
2009-01-01
An accurate circuit of PWM/PFM mode converting and a circuit of auto-adaptively adjusting dimension of power transistor are described. The duty cycle of the signal when the control mode converts can be gained accu-rately by using ratios of currents and capacitances, and an optimal dimension of power transistor is derived with different loads. The converter is designed by 0.35 μm standard CMOS technology. Simulation results indicate that the converter starts work at 0.8 V input voltage. Combined with synchronized rectification, the transfer efficiency is higher than 90% with full load range, and achieves 97.5% at rating output.
Four Quadrants Integrated Transformers for Dual-input Isolated DC-DC Converters
Ouyang, Ziwei; Zhang, Zhe; Andersen, Michael A. E.;
2012-01-01
A common limitation of power coupling effect in some known multiple-input dc-dc converters has been addressed in many literatures. In order to overcome this limitation, a new concept for decoupling the primary windings in the integrated multiple-winding transformers based on 3-dimensional (3D...... perpendicular primary windings, a name of “four quadrants integrated transformers” (FQIT) is therefore given to the proposed construction. Since the two primary windings are uncoupled, the FQIT allows the two input power stages to transfer the energy into the output load simultaneously or at any...
Wind Energy Conversion System with Boost Converter and CHB MLI with single DC input
Porselvi T
2014-03-01
Full Text Available The developments in power electronics technology have led to the developments in the wind energy conversion system (WECS. The output voltage of the WECS depends on the speed of the wind, which is not constant. Hence, a power conversion unit is required to maintain the output voltage of the WECS constant. This paper presents the design of a boost converter and a voltage controller for maintaining the DC-link voltage of the system constant. A new topology of the cascaded H-bridge multilevel inverter (CHB MLI is proposed for the DC/ AC conversion. The proposed topology eliminates the requirement of separate DC sources. The multilevel inverter is controlled by the selective harmonic elimination pulse width modulation (SHE-PWM technique. The system is simulated in MATLAB/ Simulink for varying wind speeds. The simulated waveforms of the PMSG rotor speed, the PMSG voltage, the boost converter voltage and the CHBMLI voltages are shown and the results obtained are found to be satisfactory.
Multistability and Torus Reconstruction in a DC–DC Converter With Multilevel Control
Zhusubaliyev, Zhanybai T.; Mosekilde, Erik; Pavlova, Elena V.
2013-01-01
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...
Five-Level Active-Neutral-Point-Clamped DC/DC Converter
Liu, Dong; Deng, Fujin; Chen, Zhe
Multi-level converters are getting more and more attentions because of their obvious merits such as lower voltage stress and harmonic, smaller size of output filters, and so on. In this paper, a five-level active-neutral-point-clamped (5L-ANPC) dc/dc converter is proposed for power transfer...
Comparison of two different high performance mixed signal controllers for DC/DC converters
Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.
2006-01-01
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 k......Hz implemented in the 16 MIPS, 8-bit ATTiny26 microcontroller is demonstrated....
A Super Performance Bandgap Voltage Reference with Adjustable Output for DC-DC Converter
无
2006-01-01
This paper presents a super performance bandgap voltage reference for DC-DC converter with adjustable output. It generates a wide range of voltage reference ranging from sub- 1V to 1.221 7 V and has a low temperature coefficient of 2.3 × 10 - 5/K over the temperature variation using the current feedback and resistive subdivision. In addition, the power supply rejection ration of the proposed bandgap voltage reference is 78 dB. When supply voltage varies from 2.5 V to 6 V, output VREF is 1.221 685 ± 0.055 mV.
Ali Asghar Memon; Imtiaz Hussain; Muhammad Aslam Uqaili
2013-01-01
This paper presents a gate driver circuit for the switching devices used in the asymmetrical converter for a switched reluctance machine with reduced number of isolated dc/dc converters. Isolation required in the gate driver circuit of switching devices is indispensable. For the purpose of isolation different arrangements may be used such as pulse transformers. The dc/dc converter for isolation and powering the gate drive circuits is suitable, cheaper in cost and simple to implement. It is al...
Analysis and Implementation of Dual-ZCS forward DC/DC Converter
WANG Jing-mei; LAN Zhong-wei; YU Zhong; WANG Hao-cai
2005-01-01
As the switching frequency in DC/DC converter increases, original 'hard-switch' working mode is not compatible. Another problem is the reliability, which is puzzled in single-ended forward, push-pull or bridge-like structures. In this paper, a new dual-ZCS (zero current switches) forward topology is proposed. The operating principle of soft-switch is analyzed, showing the relationship between voltage and current in time domain. Then how to calculate the key parameters of resonant network is . Finally, a prototype ZCS SMPS is implemented and tested. The results consisted with the analyzing results well, and illustrated the advantages of the proposed structure.
Soft-start mechanism with coefficients Ki optimization for DC-DC power converters
Wang, Qian; Hu, Jiajun; Chen, Houpeng; Li, Xi; Fan, Xi; Miao, Jie; Song, Zhitang
2016-10-01
This paper presents a fully digital-control soft start mechanism with coefficients Ki optimization for DC-DC power converters. During the soft start phase, a ladder reference voltage steps up gradually to make inductor current ramp up smoothly and overshoot voltage is minimized with the proposed coefficients Ki distribution. Simulation results show that massive inductor current can be well avoided during the soft start process with the proposed soft start mechanism, which only occupies a chip area of 300um×120um.
Jammes, B. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France). Laboratoire d`Analyse et d`Architecture des Systemes; Dragos, A. [Bucharest Univ. Politechnica (Romania)
1998-11-01
In this paper, artificial neural networks are used to elaborate non-linear control of the average output voltage of Buck and Boost converters. The training of the regulator is based on the adjustment technique used by indirect adaptative command structures. These techniques require a system model and performances of inputs/outputs and state models are compared. It is shown that this approach allows to generate non-linear regulators for the converters under study, but it is preferable to introduce some modifications in order to facilitate the training of the regulator. (J.S.) 4 refs.
Iwens, R. P.; Lee, F. C.; Triner, J. E.
1977-01-01
Using discrete time state variable representation, a generalized computer-aided modeling and analysis of dc-dc converters is presented. The methodology provides exact modeling and is applicable to all types of power stages and duty-cycle control, including continuous and discontinuous inductor current operation. Converter stability, transient behavior and audio susceptibility can be analytically evaluated and predicted. The generalized theory of the proposed approach to converter modeling and analysis is presented first, followed by a demonstrative example applying the theory to a constant frequency buck converter operating in continuous and discontinuous inductor current mode. Excellent agreement with laboratory test data has been observed.
Design and implementation of a switched capacitor-based embedded hybrid DC-DC converter
Bhattacharyya, Kaushik; Mandal, Pradip
2012-06-01
Here, we propose an integrated hybrid DC-DC converter suitable for high drop-out energy conscious applications. In the hybrid converter topology, along with a linear regulator two switched capacitors are used to store and recycle charge for better power efficiency. Without significant power loss the switched capacitors step down the supply voltage for the linear regulator working in low drop-out mode. The linear regulator, on the other hand, attenuates the voltage ripple that originates from the switched capacitors converter on its power supply rejection ratio. It also helps for line and load regulation. Additionally, a synthesised counter ripple is injected through the linear regulator to further reduce the output ripple. With these two techniques, for a moderate load current and an acceptable output ripple, the switching and load capacitors are reduced to a value which can be implemented within the chip. The proposed integrated converter circuit has been designed, implemented and tested in a 0.18 mm CMOS process for 3.3-1.3V conversion. With two switching capacitors of 210 pF each and 100 pF load capacitor, more than 13 mA of load current, measured peak-to-peak output voltage ripple is 146 mV. The achieved measured power efficiency is 64.97%. Exhaustive silicon characterisation of the converter is done to observe the power efficiency and ripple variation at different frequency of operations.
Liao Xiaozhong
2013-02-01
Full Text Available High Output Voltage Based Multiphase Step-Up DC-DC Converter topology with voltage doubler rectifiers is presented in this paper. High output voltage is obtained due to the series combination of voltage doubler rectifiers on the secondary side of high frequency transformers. This topology is useful in the application where the output voltage is greater than the input. The two loop control strategy has been developed in order to analyze the stable and effective working of the converter topology. Therefore the working mode analysis of the converter topology has been described in detail. The multiphase step-up DC-DC converter topology is first simulated on MATLAB and then a prototype has been designed in order to verify the simulation and experimental results. Finally the simulation and experimental results are found to be satisfactory.
Low-temperature operation of a Buck DC/DC converter
Ray, Biswajit; Gerber, Scott S.; Patterson, Richard L.; Myers, Ira T.
1995-01-01
Low-temperature (77 K) operation of a 42/28 V, 175 W, 50 kHz PWM Buck DC/DC converter designed with commercially available components is reported. Overall, the converter losses decreased at 77 K compared to room temperature operation. A full-load efficiency of 97 percent was recorded at liquid-nitrogen temperature, compared to 95.8 percent at room temperature. Power MOSFET operation improved significantly where as the output rectifier operation deteriorated at low-temperature. The performance of the output filter inductor and capacitor did not change significantly at 77 K compared to room temperature performance. It is possible to achieve high-density and high efficiency power conversion at low-temperatures due to improved electronic, electrical and thermal properties of materials.
Quasi Y-Source Boost DC-DC Converter
Siwakoti, Yam P.; Blaabjerg, Frede; Loh, Poh Chiang
2015-01-01
A new topology called “quasi-Y-source impedance network” is presented in this paper. It inherits all the advantages of the original Y-source network. In addition, the new topology draws continuous current from the source which is required for many renewable sources. It also has dc-current-blockin......A new topology called “quasi-Y-source impedance network” is presented in this paper. It inherits all the advantages of the original Y-source network. In addition, the new topology draws continuous current from the source which is required for many renewable sources. It also has dc...
Integrated Circuit of CMOS DC-DC Buck Converter with Differential Active Inductor
Kaoutar Elbakkar
2011-11-01
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.