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In this paper, a new class of bidirectional partial-resonance power converters is presented. The proposed family can be configured to interface single- or multi-port dc, single- or multi-phase ac systems at input-side and/or output-side. The proposed family offers a very modular structure, which can lead to cost reduction from a common designed module. In this converter, which accomplishes power conversion in a single stage, a small inductor placed in series with the input and output switch-bridges forms the link. This small link inductor is responsible for transferring power between different ports of the system. The proposed topologies can operate in buck, boost, and buck–boost modes of operation to step up and/or step down the voltage. In buck–boost mode of operation, the converter is controlled such that the power is entirely transferred through the link inductor; whereas, in buck or boost modes of operation only a fraction of the power is transferred through the link inductor, and the remaining power is directly transferred from input phases to the output phases. Galvanic isolation, which is typically a prominent factor contributing to power density of a converter, can be provided by means of a compact and lightweight single-phase high-frequency transformer added to the link. In comparison with earlier generations of partial-resonance inductive-link power converters, in the proposed converter, the level of link peak current and consequently power-loss, as well as voltage and current stress of switches are dramatically decreased. A very small film capacitor can be placed in parallel with the link inductor to facilitate zero-voltage-switching (ZVS) operation for all the switches/diodes. Apart from increasing the overall efficiency, minimized dv/dt stress and improvement in power density are achieved by adding the link capacitor. The proposed converter employs four-quadrant switches, i.e., bidirectional-conducting bidirectional-blocking switches, and charges the link inductor in both positive and negative directions in each cycle. In view of this, better utilization of the link inductor and lower total harmonic distortion (THD) are offered. Furthermore, two distinct switching algorithms are developed for the proposed family of converters. In this paper, the detailed behavior of the proposed family is investigated analytically, and simulation and experimental results are presented to evaluate the performance and effectiveness of the proposed converter. A low-power proof-of-concept prototype with input voltage of 59 V/161 V, load voltage of 178 V/73.5 V, maximum switching frequency of 4.9 kHz/3.65 kHz at 215 W/450 W in a step-up/step-down operation is considered for the experimental verification. [ABSTRACT FROM AUTHOR]

A single-stage three-phase ac–ac converter benefiting from a high-frequency alternating link voltage is proposed in this paper. In this converter, a very small film capacitor can transfer the energy from the input to the output, owing to the high-frequency alternating voltage of the link. This eliminates the need for large electrolytic capacitors that are typically used in dc-link ac–ac converters. Moreover, a compact high-frequency transformer at the link can replace the bulky low-frequency transformers, in case isolation is required. These features increase the power density as well as reliability of the proposed converter in comparison with the conventional dc-link converters. The number of required switches in the proposed converter is 12, which is less than the number of switches needed in matrix converters, leading to lower switching and conduction losses. Despite being single-stage, the proposed ac–ac converter is capable of both stepping up and stepping down the voltage and also frequency transformation. This eliminates the need for using cascaded power converters. In this paper, the operation principles of the proposed ac–ac converter are investigated, and variable switching frequency and fixed switching frequency control methods for operating this converter are introduced. The performance of the converter is verified through simulation and experiment. [ABSTRACT FROM AUTHOR]

In this paper, a new structure for a nonisolated boost dc–dc converter is proposed. The proposed converter generates higher voltage gain than some conventional nonisolated boost dc–dc converters. In this paper, the voltage and current equations of the elements and voltage gain in continuous conduction mode and discontinuous conduction mode are extracted. Then, the critical inductance converter is extracted and the current stresses in the switches are calculated. To achieve high voltage gain, a generalized structure based on the proposed structure generates for dc–dc converters. Meanwhile, the root mean square current relations of devices are obtained for an extended structure. Finally, the results of PSCAD/EMTDC software and laboratory prototype are used to reconfirm theoretical concept. [ABSTRACT FROM AUTHOR]

An extended-duty-ratio (EDR) boost converter is studied extensively in this paper for high voltage gain applications with a wide input (and/or output) voltage range. The EDR is a unique combination of an interleaved, multiphase boost converter and switched capacitor configuration that achieves high voltage gain with significantly lower switch voltage stress and switching losses compared to conventional high-gain solutions. Most of the switches in the multiphase EDR experience only a fixed fraction of the output voltage ($1/M, 2/M$ , etc., where $M$ is the number of phases). Through extensive analysis over a wide operating range, it is shown here that the EDR boost converter has inherent current sharing among the phases only in a limited range of duty ratio— $(M-1)/M \leq D \leq 1$. As the duty ratio reduces beyond this range as required in wide input voltage applications, inherent current sharing property is lost. In this paper, techniques to ensure current sharing under all operating zones without requiring current sensors are presented. Instead of having equal duty ratio for each phase, it is adjusted for each phase according to the operating region of the converter. Extensive analysis is presented to derive the required duty ratio changes for the different phases. The proposed concept is validated with experimental results from a 250 W, 3-phase EDR boost, and GaN-based hardware prototype. [ABSTRACT FROM AUTHOR]

A new static synchronous compensator (STATCOM) based on the diode-clamped modular multilevel converter (DCM2 C) is proposed in this paper. In this converter topology, the capacitor voltage is clamped by using a low power rating diode in each submodule. The quantity of voltage sensors is significantly reduced and is free from the number of voltage levels. Furthermore, the voltage balancing control method becomes very simple and the capacitor voltage balance speed is fast. Based on the structure of modular multilevel converter, the DCM2C-STATCOM has the capability of Var compensation and negative-sequence current compensation. The topology characteristics and compensation control method of DCM2C-STATCOM are investigated in this paper. Experimental results obtained from a laboratory prototype validate that the capacitor voltage of the proposed DCM2C-STATCOM can be well balanced and the Var and negative-sequence current compensations are effective. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) systems having rechargeable batteries are prone to be complex and costly because multiple converters are necessary to individually regulate a load, PV panel, and battery. This paper proposes novel nonisolated multiport converters (MPCs) integrating a bidirectional pulsewidth modulation (PWM) converter and phase-shift-switched capacitor converter (PS-SCC) for standalone PV systems. A PWM converter and PS-SCC are integrated by reducing the total switch count, realizing the simplified system and circuit. In the proposed MPCs, two control freedoms of duty cycle and phase shift angle are manipulated to individually regulate the load, PV panel, and/or battery. The detailed operation analysis was performed to mathematically derive gain characteristics and zero voltage switching operation boundaries. For the battery discharging mode, in which the PV panel is not available and the MPC behaves as a single-input–single-output converter with two control freedoms available, the optimized control scheme achieving the lowest rms current is also proposed to maximize power conversion efficiencies. Various kinds of experimental verification tests using a 200-W prototype were performed to verify the theoretical analysis and to demonstrate the performance of the proposed MPC. [ABSTRACT FROM AUTHOR]

In this paper, the Z-source converter is introduced to power factor correction (PFC) applications. The concept is demonstrated through a wireless power transfer (WPT) system for electric vehicle battery charging, namely Z-source resonant converter (ZSRC). Due to the Z-source network (ZSN), the ZSRC inherently performs PFC and regulate the system output voltage simultaneously, without adding extra semiconductor devices and control circuitry to the conventional WPT system such as conventional PFC converters do. In other words, the ZSN can be categorized as a family of the single-stage PFC converters. In addition, the ZSN is suitable for high-power applications since it is immune to shoot-through states, which increases reliability and adds a boost feature to the system. The ZSRC-based WPT system operating principle is described and analyzed in this paper. Simulations and experimental results based on a 1-kW prototype with 20-cm air gap between the system primary and secondary sides are presented to validate the analysis and demonstrate the effectiveness of the ZSN in the PFC of the WPT system. [ABSTRACT FROM PUBLISHER]

A dual-input high step-up DC/DC converter with zero voltage turn-off (ZVT) auxiliary circuit is presented in this paper. The cost of whole photovoltaic (PV) power could be decreased significantly by the proposed converter because it allows two PV panels to be connected at the same time. ZVT auxiliary circuit provides soft switching in a wide range of load variations with six passive components. Turn-off switching losses could be decreased and the efficiency of the whole converter could be improved. In , the operation principle and performance characteristics of the proposed converter have been analyzed and an 800 W experimental prototype has been built to validate the analytical results in. In , a dual-input maximum power point tracking (DMPPT) control algorithm has been designed for the proposed converter. Experimental results show that two PV panels can achieve the maximum power output state separately by the proposed DMPPT control algorithm. [ABSTRACT FROM AUTHOR]

The non-inverting buck-boost converter has emerged as one of the most promising topologies for distributed maximum power point tracking applications. Pressure to reduce cost and volume of photovoltaic module integrated converters often compels bootstrap capacitor type gate drivers. The bootstrap technique is a simple and economical solution to create a floating power supply for high-side gate drivers. However, it comes with a major challenge, as the low-side switch must be periodically turned on, to recharge the high-side bootstrap capacitor. In the buck and the boost mode, one of the switching legs of the converter must be held with the high-side switch on, which eventually discharges the high-side capacitor. When the non-inverting buck-boost input voltage is regulated by means of a single voltage loop, recharging the bootstrap capacitor causes an undesired ripple in the PV module voltage, degrading the regulation quality. In order to mitigate this problem, this paper proposes a cascaded control technique, entailing regulation of the PV module voltage and inductor current. The cascaded controller dramatically improves the rejection of the disturbance induced by the periodic recharge of the bootstrap capacitor, thanks to the fast action of the current loop, regulating the average value of the inductor current. Converter transfer functions and controller design are derived and validated. Experimental results clearly show that the cascaded control scheme outperforms the traditional voltage control scheme, resulting in a better regulation of the PV module voltage. This main advantage comes at the cost of an additional measurement of the average inductor current. [ABSTRACT FROM AUTHOR]

Cascaded multilevel inverter (CMI) is one of the most popular multilevel inverter topologies. This topology is synthesized with some series-connected identical H-bridge cells. CMI requires several isolated dc sources which brings about some difficulties when dealing with this type of inverter. This paper addresses the problem by proposing a switched-capacitor (SC)-based CMI. The proposed topology, which is referred to as switched-capacitor single-source CMI (SCSS-CMI), makes use of some capacitors instead of the dc sources. Hence, it requires only one dc source to charge the employed capacitors. Usually, the capacitor charging process in a SC cell is companied by some current spikes which extremely harm the charging switch and the capacitor. The capacitors in SCSS-CMI are charged through a simple auxiliary circuit which eradicates the mentioned current spikes and provides zero-current switching condition for the charging switch. A computer-aid simulated model along with a laboratory-built prototype is adopted to assess the performances of SCSS-CMI, under different conditions. [ABSTRACT FROM AUTHOR]

This paper introduces a SEPIC-derived converter suited for alternative energy generation applications. The proposed converter utilizes tapped inductor and charge pump techniques to achieve high step-up gain and a passive regenerative snubber to attain high efficiency. Compared with earlier counterparts, the proposed converter has the advantage of continuous input current, which can be helpful in attaining accurate tracking of maximum power point of solar panels. The paper presents principle of operation, theoretical analysis, and design guidelines. Theoretical expectations were confirmed by simulation and experimental results. [ABSTRACT FROM AUTHOR]

Boost-derived hybrid converter (BDHC) is a single-stage converter that produces both dc and ac output voltages. The operation of BDHC under continuous conduction mode is satisfactory. However, the nonzero discontinuous conduction mode (NZ-DCM) and standalone ac operation restrict the stable operation of the converter. To mitigate these limitations, modified BDHC (MBDHC) is proposed in this paper. The main idea behind these changes is to redeem NZ-DCM by forced continuous conduction mode (FCM). The adverse effect of NZ-DCM in a BDHC is analyzed in terms of ac output voltage total harmonic distortion, and dc output voltage ripple. This analysis is further extended for MBDHC to highlight the benefits of FCM. Moreover, for hybrid loads, the efficiency of MBDHC is compared with its counterpart BDHC and cascaded boost inverter. [ABSTRACT FROM PUBLISHER]

The boost converter with a voltage multiplier cell allows the static gain extension by means of the switching capacitor technique, reducing the duty cycle needed to achieve the same voltage gain when compared to the conventional boost converter. However, the modeling of this converter is complex and requires the use of advanced techniques due to the resonant inductor. Thus, this paper aims to present a reduced-order model of this converter without the resonant energy exchange between the capacitors, so that the state-space averaging technique can be applied assuming small ripple in the state variables. In addition, this paper presents the design of a control system for the boost converter with a voltage multiplier cell. The adopted strategy employs an inner loop to control the input current and an outer loop for the output voltage regulation. Extensive analysis based on simulations and an experimental prototype demonstrate that the proposed modeling, although simplified, is sufficient for an adequate control system design, ensuring good voltage regulation, and fast transient responses. [ABSTRACT FROM PUBLISHER]

The modular multilevel converter (MMC or M2C) is an emerging attractive multilevel topology for medium-voltage high-power applications. The capacitor voltage balancing control and the improvement of output current rating are two challenging issues of MMC. This paper proposed a new parallel-connected diode-clamped M2C (DCM2C), in which each arm consists of two parallel-connected clusters. In this topology, the capacitor voltages can be balanced automatically without any balancing control algorithms. Theoretically, no voltage sensors are needed to measure the capacitor voltages theoretically. Thus, the control of the converter can be simplified greatly. With a simple current-sharing control, an equal current distribution can be achieved between the two clusters. Furthermore, an extended parallel-DCM2C is proposed for larger current applications, and the corresponding current-sharing control method is developed. Experimental results validated the voltage self-balancing capability of parallel-DCM2C and the effectiveness of the proposed current-sharing control. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel high step-up nonisolated single switch dc–dc converter suitable for regulating dc bus in various microsources especially for photovoltaic (PV) sources. Quadratic boost and switched-capacitor technique are used as primary and secondary circuits, respectively. A coupled inductor is applied to make a connection between them, so a high dc voltage gain is achieved. High efficiency is yield where voltage stress on active switch is alleviated by clamped capacitor; consequently, smaller \rmR\rm{DS(ON)} for power switch is required. On the other hand, input current of the proposed converter is continued, hence stress on the input source is reduced. The operating principles and steady-state analyses are discussed in detail for both continuous and discontinuous conduction modes. Also, the boundary condition is computed. To verify the performance of the proposed converter and theoretical calculations, a 250-W prototype converter is implemented with an input voltage of 24 V and an output voltage of 400 V designed especially for PV sources in continuous conduction mode operation. Finally, simulation results are confirmed by experimental results; maximum efficiency is occurred at 150 W and full-load efficiency is 92.96%. [ABSTRACT FROM AUTHOR]

Multiterminal converters eliminate using several single-input-single-output converters and simplify their topologies and reduce their cost. In this paper, a new family of multi-input converters based on three switches leg is introduced. Inputs of the proposed converters are similar and they are topologically interchangeable and have boost or buck operation modes. The proposed converter has one output that operates as an inverter. Here, all operating modes of the proposed converters and their effects on each other are investigated, in details. Also, an appropriate switching technique for the converters is given. A detailed comparison between conventional and proposed two-input converters is also presented. A two-input, one-output prototype converter has been implemented to validate the given analyses and to verify the proposed converter's performance. The experimental results are in good agreement with the theoretical and simulated analyses. [ABSTRACT FROM AUTHOR]

Conventional matrix converters (MCs) have limited voltage gain that is less than 0.866, whether for direct MC (DMC) or indirect MC (IMC). The Z-source MCs (ZSMCs) overcome the voltage gain limitation of the traditional MC and achieve buck and boost operation with reduced switches count, thereby achieving low cost, high efficiency, and reliability, compared to the back-to-back converter. Furthermore, it will leads to more MC industrial applications. This paper presents an up-to-date comprehensive overview of the different ZSMC topologies and their configurations, circuit analyses, modulation schemes, and applications. This study offers a comprehensive and systematic reference for the future development of the ZSMCs. [ABSTRACT FROM PUBLISHER]

This paper presents a novel integrated magnetic three-port converter (IMTPC) with high power density and all three ports’ current ripple cancellation. The proposed IMTPC can interface one PV port, one bidirectional battery port, and one load port of the PV-battery dc power system. Only two high power magnetic devices are needed in an IMTPC for realizing power conversion, ripple cancellation, and switch driver simultaneously. Three extra capacitors were added to achieve three ports’ current ripple cancellation. Therefore, the port of the IMTPC will always in continuous-conduction mode with “zero current ripple,” thus, size of passive filter can be reduced and accuracy of maximum power point tracking can be improved. Meanwhile, simple driving of the high-side switch can be realized by integrated magnetic winding, which is responsible for MOSFET driver's voltage level shift. The using of the integrated magnetic technique not only performs aforementioned advantages but also shows great potential for reducing the weight and volume of the dc–dc converter. Finally, experimental verifications are given to illustrate the feasibility and effectiveness of the proposed topology and control method. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel single-phase ac–ac Z-source converter based on the Γ-structure. The proposed converter uses a coupled transformer to produce the required gain. The obtained gain can be tuned by varying the turn ratio $\gamma _\Gamma$ of the transformer within the narrow range of $1 < \gamma _\Gamma < 2$. Also, the gain factor increases with decrease of the transformer turns ratio, $\gamma _\Gamma$ . Small transformer turn ratio results in more practical topology in some voltage gains. It makes the transformer design easier and reduces construction cost. Also, in the proposed topology, the input and output voltages share the same ground. In order to avoid voltage and current spikes on the switches, a commutation strategy is proposed and safe commutation is achieved without using a snubber circuit. The operating principles and steady-state analyses are presented to verify the operational concept of the proposed topology. Also, experimental results are given to verify the validation of the proposed converter. [ABSTRACT FROM AUTHOR]

Due to the merits of sinusoidal input currents and excellent conversion efficiency, buck-type active third-harmonic injection converters have received increasing attention in recent years. However, three major problems of these converters still exist in theory and practice. First, the existence of the dc-link capacitor, utilized by early researchers, causes inrush transient and distorts the input currents. Second, in some specific situations, such as wind energy conversion system and flexible ac transmission system, these converters' capabilities of generating input reactive power need sufficient improvements. Third, proper selection of the third-harmonic injection inductor is the key challenge to implement these converters, since the inductor affects not only the current ripple but also the tracking performance of the third-harmonic current. To solve these problems, this paper studies the two-stage matrix converter with third harmonics injection and demonstrates that the dc-link capacitor can be removed by bidirectional implementation and proper control of the rectifier. Then, an algorithm enhancing the input reactive power capability is developed. Thus, sinusoidal input currents are achieved and the reactive power control range is extended significantly. Moreover, the design criteria of the third-harmonic injection inductor are discussed. Finally, the proposed method is verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

This paper introduces the application of a switched-diode-capacitor voltage accumulator (SDCVA) on conventional boost converter. This study aims to obtain two different kinds of multi-input step-up converters with high voltage gains, low component stresses, low ripples, simple control, and high conversion efficiencies: one is based on the parallel SDCVA and the other based on the serial SDCVA. The double-input step-up converter based on the parallel SDCVA and the double-input step-up converter based on the serial SDCVA are, respectively, taken as an example to do theoretical analysis, including operating principles and performance analyses when they work individually and simultaneously. The two proposed converters are implemented with a voltage closed-loop control at the switching frequency of 30 kHz. Experimental results obtained from the implemented prototypes are provided to validate the feasibility and effectiveness of the proposed converters. [ABSTRACT FROM AUTHOR]

In existing half/full-bridge high-precision amplifiers, output distortion is present due to the required switch blanking time. The OCC topology does not require this blanking time but has a much higher total inductor volume compared to the half bridge. In this paper, a patented new topology is introduced that has the advantages of the OCC but with a much lower total inductor volume. The basic operation and properties of the ELOCC topology are explained including an extended optimization of the total inductor volume and an average model for control design. A prototype ELOCC current amplifier has been developed. The behavior of this prototype is in good agreement with the obtained simulation results. Even though the prototype is not fully optimized, the linearity compared to a full bridge is already impressive. [ABSTRACT FROM AUTHOR]

High step-up ratio dc–dc converters with megawatt ratings are of interest in wind turbine interfaces and high-voltage direct-current systems. This paper presents a modular multilevel dc–dc converter based on the standard boost converter topology but with the normal single switches replaced by a number of capacitor-clamped submodules. The converter is operated in resonant mode with resonance between submodule capacitors and the arm inductor. A phase-shifted switching arrangement is applied such that there is a constant number, i.e., $N$, of submodules supporting the high voltage at a time. In this operation mode, the step-up ratio is dependent on the number of submodules and the inductor charging ratio. The converter exhibits scalability without using a transformer and is capable of bidirectional power flow. An application example of a wind turbine interface with a 10 : 1 conversion ratio is demonstrated in simulation. The experimental verification of the concept using a lab-scale prototype is provided. [ABSTRACT FROM PUBLISHER]

This paper presents the performance analysis and comparison of two types of bidirectional dc–dc converters—cascaded buck–boost capacitor in the middle and cascaded buck–boost inductor in the middle for use in plug-in electric and hybrid electric vehicles. The comparison of the two converters is based on device requirements, rating of switches and components, control strategy, and performance. Each of the converter topologies has some advantages over the other in certain aspects. Efficiency analysis has been carried out for specific scenarios in vehicle applications. The simulation and experimental results are provided for both converter types. [ABSTRACT FROM PUBLISHER]

This paper introduces a digitally controlled single-phase rectifier with power factor correction (PFC) based on a modified three-level boost converter topology. In comparison with the conventional boost-based systems, the new PFC rectifier has about three times smaller inductor and significantly lower switching losses. The improvements are achieved by replacing the output capacitor of the boost converter with a nonsymmetric active capacitive divider, with a 3:1 division ratio, and by utilizing the downstream converter stage for the capacitive divider's center-tap voltage regulation. The nonsymmetric voltage divider and applied switching sequence effectively provide four-level converter behavior using the same number of components as three-level converters. As a result, a 66% reduction of the inductor compared to the conventional boost-based PFC and a 33% compared to the standard three-level solutions operating at the same effective switching frequencies are also achieved. Experimental results obtained with a 400 W, 200 kHz, universal input voltage (85 Vrms-265 Vrms) PFC prototype demonstrate three times smaller inductor current ripple than that of the conventional boost converter allowing for the same inductor reduction. Efficiency improvements of up to a 6% are also demonstrated. [ABSTRACT FROM AUTHOR]

High voltage gain dc-dc converters are required in many industrial applications such as photovoltaic and fuel cell energy systems, high-intensity discharge lamp (HID), dc back-up energy systems, and electric vehicles. This paper presents a novel input-parallel output-series boost converter with dual coupled inductors and a voltage multiplier module. On the one hand, the primary windings of two coupled inductors are connected in parallel to share the input current and reduce the current ripple at the input. On the other hand, the proposed converter inherits the merits of interleaved series-connected output capacitors for high voltage gain, low output voltage ripple, and low switch voltage stress. Moreover, the secondary sides of two coupled inductors are connected in series to a regenerative capacitor by a diode for extending the voltage gain and balancing the primary-parallel currents. In addition, the active switches are turned on at zero current and the reverse recovery problem of diodes is alleviated by reasonable leakage inductances of the coupled inductors. Besides, the energy of leakage inductances can be recycled. A prototype circuit rated 500-W output power is implemented in the laboratory, and the experimental results shows satisfactory agreement with the theoretical analysis. [ABSTRACT FROM AUTHOR]

In a photovoltaic (PV)- or fuel-cell-based grid-connected power system, a high step-up dc–dc converter is required to boost the low voltage of a PV or fuel cell to a relatively high bus voltage for the downstream dc–ac grid-connected inverter. To integrate the advantages of the high voltage gain of a switched-capacitor (SC) converter and excellent output regulation of a switching-mode dc–dc converter, a method of combining the two types of converters is proposed in this paper. The basic idea is that when the switch is turned on, the inductor is charged, and the capacitors are connected in series to supply the load, and when the switch is turned off, the inductor releases energy to charge multiple capacitors in parallel, whose voltages are controlled by a pulsewidth modulation technique. Thus, a high voltage gain of the dc–dc converter can be obtained with good regulation. Based on this principle, a series of new topologies are derived, and the operating principles and voltage gains of the proposed converters are analyzed. Finally, the design of the proposed converter is given, and the experiment results are provided to verify the theoretical analysis. [ABSTRACT FROM PUBLISHER]

In this paper, a novel transformer-less adjustable voltage quadrupler dc-dc converter with high-voltage transfer gain and reduced semiconductor voltage stress is proposed. The proposed topology utilizes input-parallel output-series configuration for providing a much higher voltage gain without adopting an extreme large duty cycle. The proposed converter cannot only achieve high step-up voltage gain with reduced component count but also reduce the voltage stress of both active switches and diodes. This will allow one to choose lower voltage rating MOSFETs and diodes to reduce both switching and conduction losses. In addition, due to the charge balance of the blocking capacitor, the converter features automatic uniform current sharing characteristic of the two interleaved phases for voltage boosting mode without adding extra circuitry or complex control methods. The operation principle and steady analysis as well as a comparison with other recent existing high step-up topologies are presented. Finally, some simulation and experimental results are also presented to demonstrate the effectiveness of the proposed converter. [ABSTRACT FROM AUTHOR]

Fuel cell stacks and photovoltaic panels generate rather low dc voltages and these voltages need to be boosted before converted to ac voltage. Therefore, high step-up ratio dc-dc converters are preferred in renewable energy systems. A new Z-source-based topology that can boost the input voltage to desired levels with low duty ratios is proposed in this paper. The topology utilizes coupled inductor. The leakage inductance energy can efficiently be discharged. Since the device stresses are low in this topology, low-voltage MOSFETs with small RDS(on) values can be selected to reduce the conduction loss. These features improve the converter efficiency. Also, the converter has a galvanic isolation between source and load. The operating principles and steady-state analysis of continuous and discontinuous conduction modes are discussed in detail. Finally, experimental results are given for a prototype converter that converts 25 V dc to 400 V dc at various power levels with over 90% efficiency to verify the effectiveness of the theoretical analysis. [ABSTRACT FROM AUTHOR]

This paper presents a novel topology for a nonisolated bidirectional dc–dc converter with soft-switching capabilities, which usually operates at a zero-voltage-switching (ZVS) condition. A nonisolated dc–dc converter combines a buck converter and a backward boost converter into one circuit, which consists of a half-bridge power switch, an inductor, and capacitors. In order to realize ZVS conditions, the proposed converter utilizes a coupled inductor, a small independent inductor, and auxiliary switches and diodes. Due to ZVS, switching stress on switch components is reduced, and the reverse recovery problem of MOSFET antiparallel body diodes is also eliminated. Moreover, the operating modes of the proposed converter can be switched between a ZVS mode and a conventional hard-switching mode on the basis of load conditions. The soft-switching mode is for heavy loads, and the hard-switching mode is for light-load conditions. Therefore, the highest efficiency can be obtained at almost all load ranges. The detailed theoretical analyses in each mode are presented, and a 1-kW prototype is also built to verify the principle of the circuit and the theoretical analysis. [ABSTRACT FROM PUBLISHER]

In this paper, a number of alternate-cascaded switched-inductor and tapped-inductor networks have been proposed for Z-source inverters. The resulting topologies have enhanced voltage-boost capability while retaining the usual voltage-buck flexibility of a conventional voltage-source inverter. The enhanced capability is achieved by using lower rated components that can more readily be found. These components are assembled without direct series connection and hence avoid unbalanced voltage sharing problems and losses linked to balancing resistive circuits. The component count is, however, high, meaning that the proposed inverters should only be considered when a design requires multiple lower rated components rather than a few higher rated ones. Analysis, simulation, and experimental results have already validated the concepts discussed. [ABSTRACT FROM PUBLISHER]

This paper proposes a new topology for bidirectional multiinput direct dc–ac converter for clean-power-generation system, therefore, at the input port, a boost converter is used to meet the requirement of many distributed generation systems, such as photovoltaic, and fuel cell systems. The boost converter can increase the dc input voltage. This point results in a turn ratio reduction of high-frequency isolating link transformer. Furthermore, the boost inductor reduces the input current ripple, therefore, the saturation of the transformer can be avoided for higher output currents. The count of used devices has been reduced in the proposed converter. As a result, the cost, size, and the volume of the converter can be reduced. The reduced conversion steps increase the efficiency of the converter. The converter is analyzed step by step to show the principles of the operation in providing energy management based on duty-cycle variations. The system capability in different operation conditions has been simulated, and the simulation results have been compared with measurement results. Dynamic analysis and control design of the bidirectional dc–ac converter is presented based on nonlinear control by input–output feedback linearization. [ABSTRACT FROM AUTHOR]

Improving efficiency and flexibility in pulsed power supply technologies is the most substantial concern of pulsed power systems specifically with regard to plasma generation. Recently, the improvement of pulsed power supply has become of greater concern due to the extension of pulsed power applications to environmental and industrial areas. With this respect, a current source based topology is proposed in this paper as a pulsed power supply which gives the possibility of power flow control during load supplying mode. The main contribution in this configuration is utilization of lowmedium voltage semiconductor switches for high voltage generation. A number of switch-diode-capacitor units are designated at the output of topology to exchange the current source energy into voltage form and generate a pulsed power with sufficient voltage magnitude and stress. Simulations carried out in Matlab/SIMULINK platform as well as experimental tests on a prototype setup have verified the capability of this topology in performing desired duties. Being efficient and flexible are the main advantages of this topology. [ABSTRACT FROM AUTHOR]