Conference Paper

A comparison between two current-fed push-pull DC-DC converters-analysis, design and experimentation

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Abstract

This paper compares two current-fed push-pull DC-DC power converters: the current-fed push-pull power converter or isolated boost and an alternative topology named here as the dual inductor push-pull power converter (DIC). Since this latter converter has just one primary winding, the voltage across the main switches is reduced to the half of that in the isolated boost topology; the average current in the input inductors is also halved and the RMS current in the output capacitor is smaller. The overall efficiency is increased and the power converter's volume is reduced in the DIC converter. These and other improved design characteristics make this alternative topology more attractive than the isolated boost for equivalent applications. Analytical equations, output characteristic curves and computer simulations of both power converters are compared. An experimental breadboard of 480 W power has been assembled in order to verify the performance of the DIC power converter. The main results are provided

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... Nevertheless, previous literature does include some papers on single-stage, ac-dc, PFC, current-fed based, isolated, converters, such as the push-pull [20] or the full-bridge [21] both working in CCM with a MBC. Among the current-fed push-pull topologies, the Dual Inductor Current-fed Push-Pull (DICPP), see Fig. 1, proposed in [22], [23] as a dc-dc converter can deal with the efficiency issues intrinsic to current-fed topologies due to complex transformer design, thanks to its simpler transformer (i.e. two windings one for the primary side and the other for the secondary side), while employing two MOSFET referenced to the same ground. In fact, the DICPP uses the same amount of switches as the classic Current-Fed Push-Pull (CPP) [23] whole only adding one more magnetic component. ...
... Among the current-fed push-pull topologies, the Dual Inductor Current-fed Push-Pull (DICPP), see Fig. 1, proposed in [22], [23] as a dc-dc converter can deal with the efficiency issues intrinsic to current-fed topologies due to complex transformer design, thanks to its simpler transformer (i.e. two windings one for the primary side and the other for the secondary side), while employing two MOSFET referenced to the same ground. In fact, the DICPP uses the same amount of switches as the classic Current-Fed Push-Pull (CPP) [23] whole only adding one more magnetic component. Furthermore, the switches used in the DICPP (S1, S2) withstand half the voltage when compared to those in the CPP, therefore the switches can be downsized in terms of voltage and the transformer requires less isolation, so its complexity is decreased even further. ...
... A dc-dc Dual Inductor Current-fed Push-Pull[22] [23]. ...
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... In addition to the work developed in [10], this paper proposes a modified P&O algorithm with a properly chosen perturbation function. Experimental tests on the proposed algorithm are carried out on a dual input inductor push-pull converter (DIIPPC) [24] with the aim of comparing the results with both classic P&O and incremental conductance (IC) algorithms. DIIPPCs achieve a high boost ratio and provide isolation between the PV arrays and the load, optimising the power transfer for every irradiation and temperature level. ...
... DIIPPCs achieve a high boost ratio and provide isolation between the PV arrays and the load, optimising the power transfer for every irradiation and temperature level. Moreover, these converters present lower output voltage ripple, lower voltage across the main switches, and a lower volt-ampere rating of the transformer than current-fed push-pull converter [24]. This paper is organised as follows: Section 2 presents the DIIPPC used for PV generation and its basic operating characteristics; Section 3 describes the adaptive P&O MPPT algorithm; Section 4 reports the parameter identification of PV panel used for the experiments; Section 5 provide details about the MPPT implementation; Section 6 discusses the experimental validation of the proposed technique and the testing methodologies; Section 7 introduces a discussion on the MPP estimation error. ...
... The basic configuration of a DIIPPC [24] is illustrated in Figure 1. DIIPPCs operate similarly to converters with a single inductor. ...
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... A photovoltaic system is not a single panel so we are indeed in need of connecting the with some panel arrays thus the panel output is so produced is not exactly the same what we actually expect- [11].Thus in addition to that of the PV system which is having capacity of 5V is not exactly providing the same . Thus the panel output needed to be guided in proper way to improve the performance of the panel and also the improve it suitably adapting the AC motor- [15]. ...
... Here the existing system have the Buck Boost converter which is having some less amount of output improvement we have implemented a interleaved boost converter that has higher out when comparing with the normal converter- [8]& [15]. ...
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... The common classification in continuous and discontinuous conduction mode is often used, but is not applicable in ol-mode. There, if the self-inductance of the reactor is small enough and only one transistor conducts, the current ramps down and remains at a small level, which is equal to the magnetizing current of the main inductance of the transformer [3,4,5]. Thus there are four operating modes (nolcmm, noldmm, olcmm and oldmm) that can be taken into account, whereby a further advantage arises that the duty-cycle range of each transistor can now be between 0 and 100 % over the complete switching period T [5,6]. ...
... The voltage source converter has a capacitor in input side which reduces applied input voltage at load side with large input current ripple [20]. The current source converters have an inductor at source side which forms a current source [21]- [22]. It has boost function with a continuous input current. ...
... The isolated current-fed push-pull converter features a low component count and simply circuitry which makes it rather reliable and simple to implement; it also benefits from a high-voltage conversion ratio [8][9][10]. Some identified drawbacks of the topology are: high switching losses, high-voltage spikes in switches, high start-up current, and central tapped transformer coils requires a bigger core and can be a serious limitation for a magnetically coupled multiport configuration [9,[11][12][13]. ...
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... Another significant drawback of the switch-mode operation is the EMI produced due to large di/dt and dv/dt. To overcome these short comings, new families of QRCs are introduced [1]- [2].Few research papers have been presented about the design and implementation of push-pull hard switched and Quasi-resonant converters [3]- [5].Push-pull converters is mainly used for medium and high power applications compared to half-bridge and full-bridge converter. It has wide duty ratio control and it can be used for multi-output applications with low output and input ripple current. ...
... Comparison between two CF push-pull DC-DC converters (single inductor and dual inductor) types was presented in [18]. The benefits of dual inductor converter are: reduced voltage across the main switches, lower current stress on inductors, reduced RMS current ripple in the output capacitor, smaller size of the transformer and each of the input inductors. ...
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... [7][8][9]. Er besteht aus einem Transformator, zwei aktiven Halbleitern, zwei Speicherdrosseln, Glättungskondensatoren und einer sekundärseitigen Gleichrichterschaltung. Das Bild 3 zeigt die Topologie mit einer Brückenschaltung am Ausgang, wobei mit einer Anzapfung der Sekundärwicklung des Transformators auch eine Mittelpunktschaltung möglich wäre.Voraussetzung für den Betrieb der Schaltung ist ein stets vorhandener Strompfad für die Induktivitäten L D1 und L D2 , da es ansonsten zu gefährlichen Überspannungen für die Transistoren kommen kann. Erreicht wird der kontinuierliche Strompfad durch Überlappung der Einschaltzeiten der Transistoren T 1 und T 2 . ...
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... ere are two forms of CFPP converters that can be identified based on the number of inductors at the input of the converter, as shown in Fig. 3.19. ey are named as dual inductor and single inductor CFPP converters and they have their own advantages and disadvantages as explained in [43]. e diodes of the voltage doubler rectifier or rectifier with center tap winding at the secondary side of the isolation transformer can be replaced with active power switches, as shown in Fig. 3.19. ...
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... La fréquence apparente vue par la source vaut alors f hach multipliée par le nombre de bras, f hach étant la fréquence de commutation des interrupteurs. Cela permet de réduire la taille des éléments de filtrages [Filho & Barbi 1996;Dang 2006] et d'offrir un fonctionnement en mode dégradé lors de la perte d'un module. Cette structure entrelacée est par exemple utilisée par [Pankow & Le Moigne 2007] pour la réalisation d'une alimentation sans interruption à pile à combustible. ...
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... However, the output and the switches aren't at the same ground. Current-Fed Converters with one and two inductors are analyzed in [3]. That paper appoints that the Boost Converter with two inductors was better. ...
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In recent years, DC/DC converters have become more and more widespread due to the development of new DC energy sources. This has led to intensive studies of DC/DC converters and new configurations have been proposed in the literature. In particular, there are very interesting high efficiency configurations. The current fed, DC/DC push-pull converter with two input inductances was thoroughly analyzed because it can achieve a high ratio between its input and output voltages and intrinsic insulation. In particular, a modification of the standard converter is proposed. The studied configuration makes ZVS operations possible and increases the efficiency of the system. This paper proposes the new configuration and reports its working principles in detail. A case study is numerically simulated. The results show the ZVS operation, with an increase in the global efficiency.
Conference Paper
A ac distribution system is very common in various commercial installations. Most of the loads require front end ac-dc converter to interact with the ac system. Also, various storage systems and renewable sources connect to the ac system through dc-ac converters. These multistage conversions in the power flow path from renewable sources and storage systems to the loads reduce system efficiency. In view of this, an ac distribution system can be replaced by a dc distribution system within a commercial facility to improve overall system efficiency. This paper proposes a module integrated dc-dc converter for integration of a photovoltaic (PV) source with a dc distribution system. Current-fed topology is suggested to avoid limitations associated with large energy storage capacitor. The converter injects very low ripple, continuous current into the dc microgrid. Effect of converter switching ripple at low insolation levels is analyzed. Use of L-C filter at the converter front end is proposed, to improve power extraction at low insolation levels. This modification also enables utilization of non-dissipative snubber circuits. The converter allows large voltage step-up ratio, suitable for integration of low voltage PV module with high voltage dc micro-grid. It has compact size and high reliability. The steady state and dynamic performance of the converter are studied through computer simulations and experimental tests.
Conference Paper
A single-output zero voltage switching push-pull converter with low switching and conduction losses for robotic applications is presented in this paper. The proposed converter is designed for output of 5 V/ 1 A with a switching frequency of 50 kHz to drive a DC servo motor used in robots. The proposed converter is compact since high switching frequency of operation is chosen. Resonant technique added to the converter reduces the switching stress, losses and thereby increases its efficiency. A prototype model of this converter is developed and the hardware is implemented. The results obtained from the experimental setup are analyzed in detail. The results reveal the superiority of the proposed method.
Conference Paper
This paper presents an isolated dc/ac system using the three-state switching cell (3SSC). This converter is meant to operate as interface converter for microgrid or stand-alone applications in conjunction with a small power generating units. This system consists in two power processing stages. The first one is a dc/dc boost converter based in the 3SSC and the second one is a classical voltage source inverter (VSI) based in the full bridge inverter. The mentioned cell added in the dc/dc stage allows the use of only two windings in the isolation transformer, as well as, the series connection of only one dc current blocking capacitor to avoid its saturation. Other relevant characteristics of the system are, the blocking voltage across the controlled switches in the dc/dc stage is low, which allows the utilization of lower drain-to-source conduction resistances (RDSon) MOSFETs, and the current through the autotransformer winding is almost continuous minimizing the hysteresis losses on the magnetic core. The operating principle of the proposed system has been analyzed in detail. In order to verify the feasibility of this topology, experimental waveforms are shown for a 1kW assembled prototype.
Conference Paper
Emerging batteries based on Li-ion cells are of significant interest for aerospace, automotive, and utility energy storage systems because of their high energy density and low maintenance. Despite these and other advantages, there have been safety and certification issues, which have prevented widespread application of Li-ion batteries for aerospace applications. The main objective of this paper is to investigate a novel approach of Self-Regulated Low Voltage Active Electric Accumulator for a starter/generator system in a typical aircraft and compare its benefits and limitations to the existing battery technologies. Computer simulations will be presented to better understand feasibility and limitations of the proposed concept design.
Conference Paper
In this paper, a soft switching single inductor push-pull converter is proposed. A push-pull converter is suitable for a low power photovoltaic (PV) AC module system because the step-up ratio of a high frequency transformer is high and the number of primary side switches is relatively small. But conventional push-pull converters do not have high efficiency because of high switching losses by hard switching and transformer losses (copper and iron losses) by high turns-ratio of the transformer. In the proposed converter, primary side switches are turned on at zero voltage switching (ZVS) condition and turned off at zero current switching (ZCS) condition through parallel resonance between secondary leakage inductance of the transformer and a resonant capacitor. Therefore the proposed push-pull converter decreases the switching loss using soft switching of the primary switches. Also, the turns-ratio of the transformer can be reduced by half using a voltage-doubler of secondary side. The theoretical analysis of the proposed converter is verified by simulation and experimental results.
Conference Paper
This paper proposes new topology for high frequency isolation stage of intelligent transformer based on bi-directional current doubler rectifier (CDR). Paper provides complete steady-state analysis of the proposed bi-directional CDR in boost mode. To facilitate the understanding of operation, the converter equivalent circuits for each operating mode with corresponding waveforms are presented. Also, mathematical analysis is done and compared with simulation results.
Conference Paper
This paper discusses the effects of unexpected bi-directional operation of Phase-Shift Full-Bridge Converter in cold redundancy (CR). According to growing trends for high efficiency at light-load, cold redundancy method is strongly required in parallel operation system. However, because of unexpected backward operation, the voltage stress of primary switches is severely increased. In this paper, the period of mode change from normal operation to backward operation is investigated. The detailed operations in backward mode are described and the main factors of the severe voltage stress are analyzed. Furthermore, characteristics of switch to reduce higher voltage stress are also presented in terms of selecting switches. The validity of this study is confirmed by the experimental results of prototype 1.6kW converters.
Article
In this paper, a soft-switching single-inductor push-pull converter is proposed. A push-pull converter is suitable for low-voltage photovoltaic ac module systems, because the step-up ratio of the high-frequency transformer is high, and the number of primary-side switches is relatively small. However, the conventional push-pull converter does not have high efficiency because of high-switching losses due to hard switching and transformer losses (copper and iron losses) as a result of the high turn ratio of the transformer. In the proposed converter, primary-side switches are turned ON at the zero-voltage switching condition and turned OFF at the zero-current switching condition through parallel resonance between the secondary leakage inductance of the transformer and a resonant capacitor. The proposed push-pull converter decreases the switching loss using soft switching of the primary switches. In addition, the turn ratio of the transformer can be reduced by half using a voltage-doubler of secondary side. The theoretical analysis of the proposed converter is verified by simulation and experimental results.
Article
An 'electrolyser' is part of a renewable energy system (RES), which breaks water down into hydrogen and oxygen gases by passing an electric current through water. A dc-to-dc converter is needed to couple the electrolyser to the system dc bus of the RES. This study proposes a two-stage soft-switched high-frequency transformer isolated dc-to-dc converter for this application. A zero-voltage transition boost converter is used as the front stage followed by an inductor-capacitor-inductor (LCL)-type series resonant converter (SRC) with a capacitive output filter. Since the boost converter maintains almost a constant bus voltage, the LCL SRC can operate with zero-voltage switching (ZVS) for the specified supply and load variations. A systematic design procedure is given followed by a detailed personal simulation program with integrated circuit emphasis (PSPICE) simulation and experimental results for the designed 2.4 kW converter cell to show the performance of the proposed converter configuration.
Conference Paper
A symmetrical, current-fed DC-DC boost converter was investigated theoretically and experimentally on a 300 W prototype in the frequency range: 40 to 110 kHz. The converter is built around an L-type half-bridge IGBT inverter. Zero-current-switching is achieved by a series resonant LC-network placed between the collectors of the IGBTs
Conference Paper
To provide a 48 volt DC bus for distributed power systems, AC-DC power converters with high power factor and isolation are required. Instead of using a conventional two stage scheme which has a boost front end followed by a DC-DC converter, a boost derived topology is chosen to achieve high power factor, isolation, and voltage step down. A newly proposed technology of soft switched insulated gate bipolar transistors (IGBTs) is used for this application to reduce the IGBT switching loss and achieve low conduction loss. The design considerations of the power stage and the control circuit are provided. A prototype converter is built to show the feasibility of the single stage scheme
Article
A current-sourced switch-mode power supply topology is developed by applying a duality principle to a voltage-sourced half-bridge converter. The converter has boost converter characteristics and is suited to low-voltage high-current input applications. It is shown to compare favorably with the center-tapped transformer converter. Two optional enhancements-nondissipative snubber networks and inductor clamping windings-are also examined. Some results obtained with a low-power prototype are presented
A High Frequency 3kW Battery Charger
  • References ''i P S Latos
  • D J Basack
REFERENCES ' ' I P. S. Latos and D. J. Basack. " A High Frequency 3kW Battery Charger ". IEEE PESC Records, 1982, pp. 341-349.
Isolated Boost Circuit for Power Factor Correction 13] Abraham I. Pressman. Switching Power Supply Design
  • E X Yang
  • Y M Jiang
  • G C Hua
  • F C Lee
I*' E. X. Yang, Y. M. Jiang, G. C. Hua and F. C. Lee. " Isolated Boost Circuit for Power Factor Correction ". Proceedings of the VPEC Power Electronics Seminar, 1992, 13] Abraham I. Pressman. Switching Power Supply Design. McGraw Hill, Inc. New York -USA, 1991, pp. 187-189.
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