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Showing papers on "Flyback converter published in 2004"


Journal ArticleDOI
TL;DR: A monolithic current-mode CMOS DC-DC converter with integrated power switches and a novel on-chip current sensor for feedback control is presented in this article, where the measured absolute error between the sensed signal and the inductor current is less than 4%.
Abstract: A monolithic current-mode CMOS DC-DC converter with integrated power switches and a novel on-chip current sensor for feedback control is presented in this paper. With the proposed accurate on-chip current sensor, the sensed inductor current, combined with the internal ramp signal, can be used for current-mode DC-DC converter feedback control. In addition, no external components and no extra I/O pins are needed for the current-mode controller. The DC-DC converter has been fabricated with a standard 0.6-/spl mu/m CMOS process. The measured absolute error between the sensed signal and the inductor current is less than 4%. Experimental results show that this converter with on-chip current sensor can operate from 300 kHz to 1 MHz with supply voltage from 3 to 5.2 V, which is suitable for single-cell lithium-ion battery supply applications. The output ripple voltage is about 20 mV with a 10-/spl mu/F off-chip capacitor and 4.7-/spl mu/H off-chip inductor. The power efficiency is over 80% for load current from 50 to 450 mA.

513 citations


Journal ArticleDOI
01 Mar 2004
TL;DR: In this paper, a high-efficiency high step-up converter with low voltage stress on power switch, power diodes and output capacitors is proposed, which consists of an energy clamp circuit and a voltage boost cell.
Abstract: As a result of the equivalent series resistor of the boost inductor, conventional boost converters are not able to provide high voltage gain. A high-efficiency high step-up converter is proposed, with low voltage stress on power switch, power diodes and output capacitors. The circuit topology of the proposed converter consists of an energy clamp circuit and a voltage boost cell. The boost converter functions as an active clamp circuit to suppress the voltage spike on power switch during the turn-off transient period. The boost converter output terminal and flyback converter output terminal are serially connected to increase the output voltage gain with the coupled inductor. By serially connecting the secondary windings of the boost inductor, a high voltage gain is achieved with less voltage stress on the power devices, such as power MOSFET and power diodes. The operational principle and steady-state analysis are described. A 35 W converter with simulation and experimental results is presented to demonstrate the performance. It shows that the efficiency of the proposed converter is very high (nearly 93%) with four times the voltage output.

458 citations


Journal ArticleDOI
TL;DR: The static and dynamic characteristics of the new multiple-input DC-DC converter are clarified theoretically, and the results are confirmed by experiment.
Abstract: In the zero-emission electric power generation system, a multiple-input DC-DC converter is useful to obtain the regulated output voltage from several input power sources such as a solar array, wind generator, fuel cell, and so forth. A new multiple-input DC-DC converter is proposed and analyzed. As a result, the static and dynamic characteristics are clarified theoretically, and the results are confirmed by experiment.

373 citations


Proceedings ArticleDOI
L. Zhu1
20 Jun 2004
TL;DR: In this article, a soft-commutating method and control scheme for an isolated boost full bridge converter is proposed to implement dual operation of the well-known soft switching full bridge DC/DC (buck) converter for bi-directional high power applications.
Abstract: A soft-commutating method and control scheme for an isolated boost full bridge converter is proposed in this paper to implement dual operation of the well-known soft switching full bridge DC/DC (buck) converter for bi-directional high power applications. It provides a unique commutation logic to minimize a mismatch between current in the current-fed inductor and current in the leakage inductance of the transformer when commutation takes place, significantly reducing the power rating for a voltage clamping snubber and enabling use of a simple passive clamped snubber. To minimize the mismatch, the method and control scheme utilizes the resonant tank and freewheeling path in the existing full bridge inverter at the voltage-fed side to preset the current in the leakage inductance of the transformer in a resonant manner. Zero-voltage-switching (ZVS) is also achieved for all the switches at the voltage-fed side inverter in boost mode operation. The proposed soft-commutating method is verified through boost mode operation of a 3 kW bidirectional isolated full bridge DC/DC converter developed for fuel cell electric vehicle (EV) applications.

285 citations


Proceedings ArticleDOI
20 Jun 2004
TL;DR: In this paper, a prototype converter system of the modular-multilevel converter (M/sup 2/LC) family is introduced, which stands out due to its stringent modular construction as well as its extremely good control characteristics.
Abstract: A versatile prototype converter system of the new modular-multilevel converter (M/sup 2/LC) family is introduced. The new concept stands out due to its stringent modular construction as well as its extremely good control characteristics. This new M/sup 2/LC concept is well suitable for a wide range of high voltage applications. The basic working principle as well as the static and dynamic behaviour is explained in detail on a single-phase AC/AC-converter enabling four-quadrant operation. The M/sup 2/LC-family has already been introduced and examined for applications like traction converters, operating directly on the power line, and network interties [Marquardt, R et al., 2003 and Lesnicar, A et al., 2002]. With this prototype converter system, the characteristics of various different M/sup 2/LC-topologies can be investigated, including single or three phase DC/AC converters as well as multiphase AC/AC converters. The prototype converter has been designed in such a way that its configuration can be quickly changed between wide ranges of topologies. A flexible control system has been implemented, which is capable of controlling up to 32 IGBTs per converter arm, independently. Next to the presentation of the converter and its control system, measurement results are presented including converter operation.

262 citations


Journal ArticleDOI
Jin Wang1, F.Z. Peng1, J. Anderson1, A. Joseph1, R. Buffenbarger1 
TL;DR: In this paper, a low-cost 10-kW converter system consisting of an isolated dc-dc converter to boost the fuel cell voltage to 400 V dc and a pulsewidth modulated inverter with filter to convert the dc voltage to two split-phase 120-V ac.
Abstract: The high installation cost is the major obstacle of the commercialization of the solid oxide fuel cell for distributed power generation. This paper presents a new low cost 10-kW converter system to overcome this obstacle. The proposed system consists of an isolated dc-dc converter to boost the fuel cell voltage to 400 V dc and a pulse-width modulated inverter with filter to convert the dc voltage to two split-phase 120-V ac. The dc-dc converter uses phase shifting to control power flow through a transformer with a metal oxide semiconductor field effect transistor full bridge on the low voltage side and a voltage doubler on the high voltage side. One IPM is used to realize the voltage doubler and the dc-ac inverter. Compared to the existing fuel cell converter systems, the proposed circuit has low cost, less component count, smaller size, and reduced dc-dc converter peak current. Simulation and experimental results are demonstrated.

235 citations


Journal ArticleDOI
TL;DR: Experimental results highlight the effectiveness of the proposed topology under wide load changes, establishing it as an appropriate solution in order to develop flyback converters, even at the power range of 500 W.
Abstract: Active clamp topologies of low power dissipation have become a very attractive solution in order to limit overvoltages in flyback converters. Although many suitable topologies have been introduced for the case of discontinuous conduction mode (DCM), where the duty cycle value depends on the load level, in continuous conduction mode (CCM) it is more difficult to appropriately design such topologies so as to "sense" load changes-due to the small duty cycle divergence under wide load variation. Taking for granted that in order to achieve high power-factor correction in these converters, CCM is a more attractive mode of operation, a drastic solution for this case that will manage to eliminate voltage stresses under wide load changes has become very essential. For this purpose, this paper presents an active clamp topology with small power dissipation, suitable for flyback converters operating in CCM mode. Its main idea is the use of a load-dependent current source, consisting of an auxiliary converter operating in DCM mode. Experimental results highlight the effectiveness of the proposed topology under wide load changes, establishing it as an appropriate solution in order to develop flyback converters, even at the power range of 500 W.

192 citations


Journal ArticleDOI
01 Nov 2004
TL;DR: In this article, the stability of a buck converter feeding a downstream dc-dc converter is analyzed for a large-signal-averaged model of the converter, and the complete analysis is carried out considering a buck dc-DC converter operating with a constant power load (CPL).
Abstract: Power-electronics-based zonal direct current (dc) power distribution systems are being considered for sea and undersea vehicles. The stability of the dc power-electronics-based power distribution systems is a significant design consideration because of the potential for negative-impedance-induced instabilities. In this paper, the dynamic properties and control of a buck converter feeding a downstream dc-dc converter are studied. The controller in this system combines an instantaneous current feedback loop using hysteresis with a proportional-integral (PI) algorithm to regulate the output voltage of the converter. Based on a large-signal-averaged model of the converter, the stability-in-large around the operation point is presented. The complete analysis is carried out considering a buck dc-dc converter operating with a constant power load (CPL). Simulations and experimental results are provided to verify the analysis.

179 citations


Patent
26 Mar 2004
TL;DR: A power supply provided with an AC/DC converter which receives AC power, converts the AC power into DC power, and outputs the DC power is defined in this paper, where the level of an output voltage of the DC/DC converter to be used by a load is defined.
Abstract: A power supply provided with: an AC/DC converter which receives AC power, converts the AC power into DC power, and outputs the DC power; a DC/DC converter which receives the DC power from the AC/DC converter, and controls a level of an output voltage of the DC/DC converter to be equal to a level of a voltage to be used by a load while the DC/DC converter supplies the output voltage to the load; a DC converter which is connected to an input of the DC/DC converter; and a DC power storage means which supplies electric power to the DC/DC converter through the DC converter.

179 citations


Journal ArticleDOI
TL;DR: The output voltage regulation of the proposed converters is achieved in a wide load and input-voltage range with constant-frequency control by employing an auxiliary transformer that couples the current paths of the two boost inductors.
Abstract: A new, two-inductor, two-switch boost converter topology and its variations suitable for applications with a large difference between the input and output voltage are described. The output voltage regulation of the proposed converters is achieved in a wide load and input-voltage range with constant-frequency control by employing an auxiliary transformer that couples the current paths of the two boost inductors.

170 citations


Proceedings ArticleDOI
27 Sep 2004
TL;DR: In this paper, a three level soft switching LLC series resonant DC/DC converter is presented, where the voltage stress of each main switch is half of the input voltage and the rectifier diodes are replaced by two-stage resonance.
Abstract: Paper presents a three level soft switching LLC series resonant DC/DC converter. ZVS is achieved for each main switch without any auxiliary circuit. Voltage stress of each main switch is half of input voltage. ZCS is achieved for rectifier diodes. Wide input/output range can be achieved under low frequency range because of two-stage resonance. Only one magnetic component is needed in this converter. Efficiency is higher in high line input, so this converter is fit for power products with hold up time requirement. The principle of operation and the characteristics of the new converter are analyzed and verified on a 500 V/spl sim/700 V input 54 V/10 A output experimental prototype, whose efficiency is 94.1% at rating condition.

Patent
06 Aug 2004
TL;DR: In this paper, an intermediate converter between a first stage boost converter and a DC-DC converter is used to maintain the regulated DC input to the DC to DC converter while reducing the operating range and increasing the operating duty cycle, so as to increase efficiency and reduce peak current and voltage stresses.
Abstract: A circuit that utilizes most of the energy stored in the bulk capacitor of an AC to DC or DC to DC converter power supply by providing an intermediate converter between a first stage boost converter and a DC-DC converter. When the bulk voltage starts to fall during the hold-up time, the intermediate converter boosts the falling voltage to maintain the regulated DC input to the DC to DC converter while reducing the operating range and increasing the operating duty cycle, so as to increase efficiency, reduce peak current and voltage stresses, reduce the size of output filter components and reduce the size of the bulk capacitance by up to half.

Patent
28 Sep 2004
TL;DR: In this article, a power conversion system includes a first converter having a DC side and an AC side, and a second converter having an inverter providing DC to AC conversion or alternately a bi-directional inverter.
Abstract: A power conversion system includes a first converter having a DC side and an AC side and a second converter having a DC side and an AC side. The DC sides of the converters are connected in series with a battery connected in parallel across the DC side of the first converter. The AC sides of the converters are connected in parallel across an AC voltage grid. A DC generating power source is coupled across the DC sides of both converters. The first converter is bi-directional with the second converter being either an inverter providing DC to AC conversion or alternately a bi-directional inverter.

Patent
27 May 2004
TL;DR: In this article, a solar array has a plurality of solar modules, each module having at least one DC/DC converter for converting the raw panel output to an optimized high voltage, low current output.
Abstract: A solar array power generation system includes a solar array electrically connected to a control system. The solar array has a plurality of solar modules, each module having at least one DC/DC converter for converting the raw panel output to an optimized high voltage, low current output. In a further embodiment, each DC/DC converter requires a signal to enable power output of the solar modules.

Patent
09 Jun 2004
TL;DR: In this article, a switching circuit for turning on/off a DC voltage outputted from a DC/DC converter and a feedback voltage detection circuit for supplying feedback voltage to the converter are controlled in synchronism with each other.
Abstract: A switching circuit for turning on/off a DC voltage outputted from a DC/DC converter and a feedback voltage detection circuit for supplying a feedback voltage to the DC/DC converter are controlled in synchronism with each other. In synchronism with a transition of a PWM signal from high level to low level, the switching circuit is immediately turned off as well as a set voltage is also instantaneously supplied from the feedback voltage detection circuit to the DC/DC converter, and in synchronism with a transition of the PWM signal from low level to high level, the switching circuit is immediately turned on thereby to supply a DC voltage charged in the DC/DC converter to a light source as well as the DC/DC converter is caused to start its boosting operation, and a feedback voltage based on a detected voltage is supplied from the feedback voltage detection circuit to the DC/DC converter.

Journal ArticleDOI
Jun Zhang1, Fan Zhang1, Xiaogao Xie1, D.Z. Jiao1, Zhaoming Qian1 
TL;DR: In this paper, a novel zero voltage switch (ZVS) pulsewidth modulation (PWM) DC/DC converter for high power, high output voltage applications is presented. But the proposed topology has simple structure and control strategy and the proposed converter achieves not only ZVS of active switches in the entire load ranges but also soft commutation of the output rectifier diodes.
Abstract: This paper presents a novel zero voltage switch (ZVS) pulse-width modulation (PWM) DC/DC converter for high power, high output voltage applications. By using two active switches in the secondary side of a transformer, the proposed converter achieves not only ZVS of the active switches in the entire load ranges but also soft commutation of the output rectifier diodes. The proposed topology has simple structure and control strategy. Simulation results and experimental results of a 2.8 kW 200 kHz DC/DC converter are presented.

Proceedings ArticleDOI
27 Sep 2004
TL;DR: In this paper, a three-loop control scheme, including a dedicated input voltage controller, is proposed to achieve equal sharing of the input as well output voltages by the series connected modules.
Abstract: This paper proposes a new modular configuration, namely the input-series and output-series connection for DC-DC converters. A three-loop control scheme, including a dedicated input voltage controller is proposed to achieve equal sharing of the input as well output voltages by the series connected modules. The reference to the input voltage loop is chosen as the average of all converter input voltages. Such a reference minimizes the interaction among the various control loops. The proposed scheme is validated experimentally on a 400 W prototype system comprising of two forward converters.

Journal ArticleDOI
TL;DR: In this article, a new phase shift full bridge (PSFB) converter with series-connected two transformers is proposed, which shows wide zero voltage switching (ZVS) ranges and no output inductor is needed since each transformer individually acts as an inductor or a transformer during different times of the switching cycle.
Abstract: A new phase shift full bridge (PSFB) converter with series-connected two transformers is proposed. The proposed converter shows wide zero voltage switching (ZVS) ranges and no output inductor is needed since each transformer individually acts as an inductor or a transformer during different times of the switching cycle. The operational principle, large signal modeling, and design equations are presented. Experimental results demonstrate that the proposed converter can achieve a significant improvement in the efficiency for a 100W (5 V, 20 A) telecommunication on-board power supply.

Journal ArticleDOI
TL;DR: The experimental results presented in the paper evidence both the achievement of step-up dc-ac conversion with good accuracy and robustness in front of input voltage and load perturbations, thus validating the proposed approach.
Abstract: This paper presents a sliding-mode control design of a boost-buck switching converter for a voltage step-up dc-ac conversion without the use of any transformer. This approach combines the step-up/step-down conversion ratio capability of the converter with the robustness properties of sliding-mode control. The proposed control strategy is based on the design of two sliding-control laws, one ensuring the control of a full-bridge buck converter for proper dc-ac conversion, and the other one the control a boost converter for guaranteeing a global dc-to-ac voltage step-up ratio. A set of design criteria and a complete design procedure of the sliding-control laws are derived from small-signal analysis and large-signal considerations. The experimental results presented in the paper evidence both the achievement of step-up dc-ac conversion with good accuracy and robustness in front of input voltage and load perturbations, thus validating the proposed approach.

Proceedings ArticleDOI
20 Jun 2004
TL;DR: In this paper, a new three-phase series resonant converter is proposed and the principle working of the converter is described analytically in detail for switching frequencies equal to the resonant frequency.
Abstract: This paper proposes a new three-phase series resonant converter. The principle working of the converter is described analytically in detail for switching frequencies equal to the resonant frequency and for switching frequencies greater than the resonant frequency. Additionally, detailed simulations are performed to analyse the converter. Based on the analysis, design criteria for a 5 kW breadboard are derived. The 5 kW breadboard version of the converter has been built to validate the analytical investigations and simulations experimentally. Moreover, the breadboard is used to investigate the ZVS and ZCS possibilities of the topology and the influence of the deadtime and the switching frequency on the overall efficiency.

Proceedings ArticleDOI
27 Sep 2004
TL;DR: In this paper, a modular AC-AC matrix converter and its control system are described, which consists of a matrix connection of capacitor-clamped H-bridge switch cells and the output of each switch cell can assume three voltage levels during conduction.
Abstract: Implementation of a new modular AC-AC matrix converter and its control system are described. The converter consists of a matrix connection of capacitor-clamped H-bridge switch cells. The AC output of each switch cell can assume three voltage levels during conduction. Input and output three-phase AC waveforms are synthesized from pulse-width modulation of the DC clamp capacitor voltages. The space-vector modulation approach can be adapted to control this converter. A control algorithm is described that can be reduced to an equivalent DC-link converter. This controller is implemented using programmable logic devices and a flash-memory look-up table. Operational waveforms are presented.

Journal ArticleDOI
TL;DR: In this paper, a power conditioning unit is designed for the solid oxide fuel cell, which can be used for other fuel cells with converter and the inverter of different ratings, but the control strategy will remain the same.

Journal ArticleDOI
TL;DR: In this paper, the design and analysis of a zero-current-switched (ZCS) bidirectional flyback dc/dc converter is addressed. But the work is limited to the case of a single-input single-output (SISO) switch.
Abstract: This paper addresses the design and analysis of a zero-current-switched (ZCS) bidirectional flyback dc/dc converter. The converter is based on extending a previously developed unidirectional ZCS flyback converter and replacing the output diode with a controlled switch, which acts as either a rectifier or a power control switch in the corresponding power flow direction. By adding an auxiliary winding in the coupled inductor, a switch, and a capacitor, the hard-switching design is converted into a soft-switching one. The technique utilizes the leakage inductance of the flyback coupled inductor to create zero-current-switching conditions for all switches in both power flow directions, leading to reduced switching losses, stresses, and electromagnetic interference. The operating principles of the converter and experimental results have been presented.

Journal ArticleDOI
TL;DR: Experimental and simulation results confirm the theoretical expectations and the circuit compares favorably with a quadratic boost converter regarding the count of devices and efficiency, even if it presents a lower DC gain.
Abstract: By splitting the output capacitor of a basic boost converter, and combining the resulting capacitors with the main switch in the form of a switched-capacitor circuit, a new step-up structure is realized. Without using a transformer, a high line-to-load DC voltage ratio is obtained. An output filter is added, as usual, in boost converters for getting a free-ripple output. The circuit compares favorably with a quadratic boost converter regarding the count of devices and efficiency, even if it presents a lower DC gain. A DC analysis of the novel converter is presented. Experimental and simulation results confirm the theoretical expectations. By increasing the number of capacitors in the switched-capacitor circuit, higher gains can be obtained. Versatility, high voltage gain and good transient response are the features of the proposed converter.

Patent
12 Mar 2004
TL;DR: In this article, the authors present a method for operating a frequency converter (26) of a generator (14) in particular of a wind energy turbine (10), in the event of a substantial grid voltage drop, wherein the frequency converter comprises a generator-side power converter (32), to be connected to the generator, a grid-side Power Converter (28), and a DC link circuit (30) for connecting the generator side power converter(32) to the grid-sensor power converter, comprising the step of generating the amount of reactive current to be supplied to
Abstract: The method for operating a frequency converter (26) of a generator (14) in particular of a wind energy turbine (10), in the event of a substantial grid voltage drop, wherein the frequency converter (26) comprises a generator-side power converter (32), to be connected to the generator (14), a grid-side power converter (28) to be connected to the voltage grid (18), and a DC link circuit (30) for connecting the generator-side power converter (32) to the grid-side power converter (28), comprises the step of generating the amount of reactive current to be supplied to the grid (18) by controlling the frequency converter (26).

Patent
Matthias Wendt1, Peter Lürkens1
22 Dec 2004
TL;DR: In this paper, the authors proposed a DC/DC converter for a decentralized power generation system, where the converter is physically separated from a power receiving component and connected to such a power-consuming component via a DC bus.
Abstract: The invention relates to a DC/DC converter for use in a decentralized power generation system. If a DC/DC converter is physically separated from a power receiving component and connected to such a power receiving component via a DC bus, a short-circuit on the DC bus may endanger the system and service personnel. In order to minimize such a risk, it is proposed that the DC/DC converter comprises a converting component for DC/DC converting a direct current supplied by a power generating unit and for supplying a resulting converted direct current to a DC bus, and that the DC/DC converter comprises in addition a control component arranged to monitor a voltage at the outputs of the DC/DC converter and to cause the converting component to enter a short-circuit protection mode if the monitored voltage lies below a predetermined voltage threshold. The invention relates equally to a corresponding system and to a corresponding method.

Proceedings ArticleDOI
20 Jun 2004
TL;DR: In this paper, a new active clamping current-fed half-bridge converter has been proposed, which is suitable for fuel cell based power generation systems, and the proposed converter has outstanding advantages over the conventional dc-dc converters with respect to high efficiency, high power density, and high component utilization.
Abstract: In this paper, a new active clamping current-fed half-bridge converter has been proposed, which is suitable for fuel cell based power generation systems. The proposed converter has outstanding advantages over the conventional dc-dc converters with respect to high efficiency, high power density, and high component utilization. In special, the proposed converter has predominant high boosting output voltage and high efficiency characteristics under the inherently severe low output voltage of the fuel cell through the overall load conditions. Moreover, the developed converter has been experimentally tested with the help of a fuel cell simulator, which is developed by Sungkyunkwan Univ. and can generate the V-I characteristics of polymer electrolyte membrane fuel cell (PEMFC), so that the performance of the proposed converter could be effectively examined and the validity of the converter could be verified.

Journal ArticleDOI
TL;DR: In this paper, the main mathematical concept of the new control algorithm is introduced and simulations as well as experimental results are presented.
Abstract: Pulse Train/spl trade/ control technique is introduced and applied to flyback converter operating in discontinuous conduction mode (DCM). In contrast to the conventional pulse width modulation (PWM) control scheme, the principal idea of Pulse Train is to achieve output voltage regulation using high and low power pulses. The proposed technique is applicable to any converter operating in DCM. However, this work mainly focuses on flyback topology. In this paper, the main mathematical concept of the new control algorithm is introduced and simulations as well as experimental results are presented.

Journal ArticleDOI
TL;DR: In this paper, two new topologies characterized by no deadtime and small valued filter inductor, the Dual-Bridge dc-dc converter and the dual-bridge dc-DC converter with ZVS, are presented and analyzed.
Abstract: Two new topologies characterized by no deadtime and small valued filter inductor, the Dual-Bridge dc-dc converter and the Dual-Bridge dc-dc converter with ZVS, are presented and analyzed. Compared to the conventional Full-Bridge converter, the dc-dc converters with the proposed topologies have lower input current ripple, less stress on power switching components and smaller output filter inductor. Simple self-driven synchronous rectification can be used in the new topologies for high efficiency implementation. Prototype dc-dc converters have been tested for the verification of the principles. Both simulations and experiments verify the feasibility and advantages of the new topologies. The advantages and disadvantages of the topologies are discussed.

Book
01 Jan 2004
TL;DR: In this article, the key components of rectification, inversion, cycloconversion, and conversion circuits are discussed. And switching, voltage and current relationships, and converter properties, operation, control, and performance as utilized in most practical applications.
Abstract: This text reveals all key components of rectification, inversion, cycloconversion, and conversion circuits. It authoritatively describes switching, voltage and current relationships, and converter properties, operation, control, and performance as utilized in most practical applications. Authored jointly by a veteran scholar and an accomplished res