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A selection switch based cell-to-cell voltage equalizer requires only one dual-port dc–dc converter shared by all the cells. A cell-to-cell voltage equalizer is proposed that utilizes a capacitively level-shifted Cuk converter and low-frequency cell selection switches. The absence of isolation transformer and diodes in the equalizer leads to high efficiency, and the use of low-frequency selection switches significantly reduces the cost of the drive circuits. A low-frequency cell selection network is proposed using bipolar voltage buses, where the switch count is almost half, compared to the existing low-frequency cell-to-cell equalizers for the case of a large number of cells. A novel approach for cell voltage recovery compensation is proposed, which reduces the number of operations of the selection switches and the equalization time. The proposed equalizer is implemented with relays and verified with an eight-cell Li-ion stack. The developed prototype shows the efficiency of over 90% and good voltage balancing performance during charging, discharging, and varying load conditions. Experimental results also show about one order of magnitude reduction in the number of relay switchings and a significant reduction in equalization time using the proposed voltage compensation.

In this article, an e-bike charging solution for two wheelers, is presented. This e-bike charger is realized by a Cuk converter followed by a LLC resonant converter with an improved power quality (PQ) input current indices. The pulsewidth modulated Cuk converter is operated in discontinuous conduction mode of its output side inductor, which leads to a voltage follower approach for input current shaping. Thus, the control loop is greatly simplified as it consists of a single voltage loop. The e-bike battery charging algorithm is implemented in variable frequency controlled HB LLC resonant converter followed by a diode rectification at its output stage. Furthermore, a $\text{550}\;\text{W}$ , constant current/constant voltage charger with a maximum current rating of $\text{10}\;\text{A}$ is developed to charge a $20AH$ e-bike battery. A variable dc link reference voltage estimator is presented, which varies the dc link voltage and extends the output voltage range for charging e-bike battery of varying voltage rating from 42– $\text{80}\;\text{V}$ . Moreover, a resonant frequency optimizer loop is also proposed, which reduces the turn-off losses during charging a deeply discharged battery. The behavior of this charger is exhaustively analyzed under steady state and transient conditions and the PQ at the input, is found to comply the international standard of $IEC-61\,000-3-2$ .

This article presents an improved power quality Cuk-converter-fed isolated LLC resonant converter for an electric vehicle battery charger (EVBC), intended typically to charge a small two- or three-wheel-driven electric vehicle (EV) using up to 20-Ah battery. The proposed topology consists of two converters, comprising of the first stage for power factor correction (PFC) and the second stage for effective charging of the EV battery using a constant-voltage and constant-current mode control algorithm. In the first stage, the Cuk converter performs PFC by operating in the continuous conduction mode of the primary inductor, while the LLC resonant converter converts the dc-link voltage to the isolated dc voltage required for the EVBC. The proposed converter uses a frequency control algorithm to actively vary the intermediate dc-link voltage based on the state of charge of the battery leading to reduced turn- off losses in the LLC converter switching devices. The proposed converter is designed and simulated in MATLAB. Simulated results are analyzed and discussed in detail. Finally, a 580-W 10-A experimental prototype of the EVBC is developed, and test results are presented to demonstrate the effectiveness of the proposed topology. The proposed converter exhibits excellent power quality indices adhering to the IEC-61000-3-2 international standard.

Multioutput converters with single input source are currently studied as an alternative to conventional dc–dc topologies in order to improve power density in low-power multiload applications. This paper reviews three different ways in which a boost topology can be customized to supply multiple outputs. The first way uses a charge-sharing approach using individual switches to distribute inductor energy to different capacitors. The second method of creating a multiport converter (MPC) combines two converters with similar front end to generate two outputs using only one controlled switch. Using this method, a boost converter can be combined with single–ended primary–inductor converter (SEPIC), Cuk, and current source converter topologies. The third method uses time multiplexing of switches to produce two regulated ports and is referred to as switched-boost action. This method uses relatively less number of switches and allows regulation and control of all the outputs. Practical utility of switched-boost action based MPC is reported in this paper. This switched-boost MPC is applied to a renewable power converter system to interface a solar panel, a battery, and home loads to produce a 12-V and a 48-V bus. The 12-V bus is interfaced to battery and capable of optimally charging the battery in constant current–constant voltage (CC-CV) mode. The converter is demonstrated to operate with solar panel as it supplies a 12-V battery and a 48-V load bus. When the solar power is not available, the converter automatically goes into a mode in which the 12-V battery supplies the loads on the 48-V bus.

This paper presents the operation principle and benefits of a novel power converter topology named three-level two-stage decoupled active neutral point clamped (3L-TDANPC) converter, which is implemented based on a hybrid utilization of silicon (Si) insulated gate bipolar transistors (IGBTs) and silicon carbide (SiC) metal–oxide semiconductor field-effect transistors ( mosfet s). The 3L-TDANPC converter can achieve high efficiency with limited number of SiC mosfet modules while keeping balanced loss distribution among the switching devices, which helps increase the converter power ratings. In addition, in this 3L-TDANPC converter, the SiC mosfet has a potential to ride through short-circuit fault because of the presence of Si IGBTs. The key challenges that are associated with system resonant current are investigated and the methods to damp such resonant current are proposed and explained in detail. The simulation and experimental results based on a 1-MW 3L-TDANPC converter prototype confirm the expected benefits of this proposed converter and the effectiveness of the proposed resonant current damping methods.

A new isolated current-fed zero-current switched (ZCS) front-end dc/dc converter based multilevel inverter is proposed for multi-input applications. The proposed front-end converter with only two controllable switches integrates two different renewable energy sources, resulting in an advantageous compact structure and low conduction losses. The ZCS turn- off is achieved in both the controllable switches with the proposed modulation scheme. The converter maintains ZCS turn- off under a wide load, as well as input voltage variations by employing frequency modulation along with a variable duty ratio technique. Simple structure, soft switching, high gain, and automatic load regulation make the converter structure novel for simultaneous power management in multi-input renewable energy applications. Converter operation and design guidelines have been outlined. A laboratory prototype of the proposed converter is developed and tested at 300-W power level. Simulations and experimental results demonstrate the robust performance of the converter under load, as well as input source voltage variations.

Energy storage devices are essential to provide voltage and frequency stability in renewable energy sources, such as solar and wind. Due to operational requirements of distributed generation systems, energy storage devices like batteries and supercapacitors need bidirectional dc-dc converters to allow charge or discharge exchange according with the necessary conditions. In this paper, a new nonisolated bidirectional quadratic converter characterized by high voltage gain in both step-down (Buck) and step-up (Boost) operation modes is proposed. In addition to the wide conversion range, it presents continuous input and output current and reduced charging/discharging ripple. All these features allow an optimized operation between the dc bus and storage devices. The operation principle of the proposed converter in both condition modes (step-down and step-up), the converter design, as well as the theoretical analysis in different conditions will be discussed. Finally, the performance of the proposed converter is confirmed through simulation and experimental results. info:eu-repo/semantics/publishedVersion

This paper presents a dc/dc buck–boost converter topology with high-voltage gain and dual outputs. Unlike many of the high step-down/step-up dc/dc converters, this topology uses a relatively ower number of LC components and three active semiconductor devices switched in a nonoverlapping way. Due to the duty cycle limitation, high gain (typically more than 4) is very difficult to achieve in a single-stage regular buck–boost dc/dc converter. In the proposed converter, the overall gains at both the output ports are nonlinear functions of duty-cycles of the power devices, which help achieve an overall step-down/step-up gain of 10–15. An experimental prototype converting 48 V dc to ±5 V dc at 100 W with closed loop control is developed in order to verify the operation and effectiveness of the proposed converter structure. An output voltage ripple of ±1% and a conversion efficiency of 94% are achieved according to the experimental results.

International audience; In this paper, a robust voltage control is designed for a floating interleaved boost converter with high voltage gain. The proposed controller has an inner loop based on super-twisting sliding mode algorithm, which has continuous control signal and the sliding surface is defined for the inductor current. The reference current value is generated by active disturbance rejection control (ADRC) algorithm in the outer loop, based on the output voltage error. The stability of the sliding mode inner loop and the ADRC outer loop are proven using Lyapunov stability theorem and Routh-Hurwitz criteria, respectively. The robustness of the proposed controller is analyzed in depth, and validated by the simulations and experimental results obtained with a 100 W prototype converter.

Soft-switching techniques have become very attractive in bidirectional grid-tie dc–ac converters utilizing high-frequency link transformers for galvanic isolation. This paper presents a new pulse-width modulation (PWM) switching technique for controlling a bidirectional isolated dc–ac–ac converter along with its soft-switching method. The proposed PWM technique has the ability to control the input dc current and to inject a sinusoidal three-phase current to the grid at unity power factor. In the first stage, an H-bridge converter is used to convert the dc voltage to a high-frequency square-wave single-phase voltage. In the second stage, a matrix converter is used to convert the high-frequency voltage waveform to conventional three-phase voltage synchronized with the grid. Therefore, a single-phase high-frequency transformer is used to link the H-bridge output voltage to the matrix converter input voltage. The proposed soft-switching technique is achieved by connecting shunt ceramic capacitors across all converter switches. The mathematical model and the circuit operation for soft-switching are presented along with the voltage controllable limits. The effectiveness of the proposed technique has been verified experimentally using a laboratory prototype.

A novel hybrid five-level voltage source converter for high-efficiency applications is investigated in this paper. Compared with traditional multilevel converters, this hybrid multilevel converter generates desired staircase voltage levels with a reduced number of power devices and isolated drivers at higher voltage levels. It has redundant switching state combinations in hybrid multilevel converter, which makes it easy to balance flying capacitor voltages and realize fault-tolerant operation. A voltage balancing control strategy based on switching state redundancies is presented for the hybrid multilevel converter, to generate desired levels and also keep voltage balance of flying capacitors at the same time. The performance of the hybrid multilevel converter under various operating conditions is investigated in MATLAB/Simulink. The effectiveness of the proposed hybrid multilevel converter is validated by experiment results.

This paper presents an improved efficiency impedance control network (ICN) resonant dc–dc converter that maintains zero-voltage switching (ZVS) and near-zero-current switching (ZCS) across wide ranges in input and output voltages and output power. The improvement in efficiency in this burst mode operated converter is achieved through an optimized startup control that minimizes its startup transient and helps the converter maintain ZVS and near-ZCS operation, even during the startup for each burst cycle. This optimization of startup is made possible by a new accurate time domain model for the ICN converter waveforms that helps reduce the number of non-ZVS transitions by 75%. A prototype 200 W, 500 kHz ICN resonant converter designed to operate over an input voltage range of 25–40 V and output voltage range of 250–400 V is built and tested. The prototype ICN converter achieves a peak efficiency of 97.2% and maintains greater than 96.2% full power efficiency at 250 V output voltage across the nearly 2:1 input voltage range, and maintains full power efficiency above 94.6% across its full input and output voltage range. The converter also maintains efficiency above 93.6% over a 10:1 output power range across its full input and output voltage range.

A systematic method of designing a zero terminal current ripple integrated magnetic Cuk converter for photovoltaic (PV)-to-battery applications is presented in this paper. The four-winding-coupled inductor design consists of two inductors and a two-winding transformer coupled on a common EE-core. The core design uses a simplified flux-reluctance model to arrive at the area product formulation for this kind of a four-winding structure. The zero-ripple condition in the terminal currents is achieved by controlling the coupling coefficients by means of air-gap reluctances in the core. Unlike the earlier designs for this converter, it provides a completely analytical approach to design this converter for a range of duty ratio. The validity of the proposed method is confirmed using finite element analyses (both two dimensional and three dimensional), thermal validation, and circuit simulations in PSpice. The zero-ripple condition is verified experimentally.

This paper proposes a novel single-switch dc/dc converter for the future renewable electric energy delivery and management system to implement the distributed renewable energy resources (DRER). The DRER is responsible for the maximum power point tracking of the photovoltaic panel (PV) module and also for the control of central energy storage device. Due to the characteristics of the PV module and the dc-bus, the single power stage must provide low current ripple in the input and output terminals, must operate with output current and voltage regulation, and present a high-voltage conversion ratio. To achieve such features, this paper proposes a novel integrated Boost–Zeta converter. To avoid a complex modeling and control, we propose a disaggregation concept for this. Experimental results are presented for the purpose of operating the converter and also for the operation of the system.

This paper proposes a dual-input central capacitor dc/dc converter for distributed photovoltaic (PV) power harnessing, which can be used to boost dual input sources with minimized semiconductor voltage/current stress and converter rating. Also the proposed circuit could realize the independent maximum power point tracking capability for two input PV sources. This paper analyzes the operational principle of the proposed dual-input central capacitor dc/dc converter under both continuous conduction mode and discontinuous conduction mode and presents a comparative study between dual-input central capacitor converter and its counterparts. Besides, an adaptive control method considering PV power difference, operational safety and efficiency is elaborated. Finally, the proposed converter along with its adaptive control method was verified through matlab simulation and a laboratory prototype.

A new current-fed zero-current switching (ZCS) three-phase dc–dc converter topology is proposed in this paper. The converter architecture consists of a current-fed three-phase three-leg IGBT bridge, three single-phase high-frequency transformers with star-connected primary, and three single-phase rectifier bridges. Each secondary winding of the high-frequency transformer forms the input for single-phase rectifier bridges at the output. The parallel-connected outputs of these bridges supply the desired load. The three-leg IGBT-based primary bridge is modulated with constant frequency phase-shift pulse width modulation technique. ZCS for all the primary IGBTs is achieved with the aid of transformer leakage inductance, small auxiliary ac capacitors connected in parallel to secondary side of single-phase transformers and modulation scheme. Detailed operation with converter design and analysis are discussed. Digital simulation and experimental test results on a laboratory prototype are presented to investigate the converter design and operation.

This paper describes the development of a bilateral dc/dc converter rated at 1500 V with a peak power of 500 kW for battery energy storage systems supporting railway dc feeder systems. The dc/dc converter converts regenerated power from a braking train and charges the batteries. The dc/dc converter discharges the stored energy to feed the train during powering. The converter main circuit and the control system are described, and successful test results obtained at the factory are reported. For the main circuit test, a special test method was applied. For the control system test, a real-time digital simulator was used for hardware-in-loop tests. In addition to the converter tests, the results from dc feeder system tests with an actual rectifier and battery bank are also presented.

This paper presents a solar photovoltaic array fed water pumping system employing a switched reluctance motor (SRM) drive. The electronic commutation of the SRM drive at fundamental frequency offers reduced switching losses in a mid-point converter and considerably increases the efficiency of proposed system. The speed of SRM is controlled by varying the dc-bus voltage of the mid-point converter. A dc–dc Cuk converter operating in continuous conduction mode (CCM) is used for dc-bus voltage control. The CCM operation of inductors helps to reduce the ringing effect and decreases the losses of dc–dc converter. Current and voltage stresses on devices including switching stress of Cuk converter are also reduced in CCM. The Cuk converter facilitates the continuous and smooth input/output currents to SRM drive with boundless region for maximum power point tracking (MPPT) operation. The adjustment in step size of an incremental conductance MPPT algorithm facilitates the soft starting of SRM drive. The proposed system, subjected to dynamically atmospheric conditions is designed, modeled, and simulated using MATLAB/Simulink environment. A prototype of proposed configuration is also developed and its performance is validated with test results for the control of speed over varying insolation levels.

Submodule (SM) capacitor is a key component in a modular multilevel converter (MMC), the selection of which must consider the component’s specifications and the requirements of the targeted converter application. This paper focuses on the capacitor selection for MMCs in applications including high-voltage direct current (HVDC) transmission and static VAr compensation using metalized polypropylene film (MPPF) capacitors. The dominant ageing mechanisms of the MPPF capacitors are reviewed to define their operational limits. A straightforward computational procedure and a set of curves are presented to assist the capacitor selection, taking into account criteria in the aspects of maximum capacitor voltage, capacitor voltage ripple, SM voltage capability, and capacitor ripple current stress. Simulation shows the validity of the method and demonstrates its use in design examples.

A power factor preregulator (PFP) usually serves as the first stage of an active two-stage ac/dc converter in a variety of applications including inductive heating systems, wireless charging systems, and onboard chargers for plug-in electric vehicles. Conventionally, boost-type PFPs are utilized to regulate the dc-link voltage at a fixed voltage; however, a variable dc-link voltage can enhance the overall efficiency of the converters. In this paper, an interleaved single-ended primary inductor converter (SEPIC) with coupled inductors is proposed as the PFP stage for two-stage ac/dc converters. The converter is designed to operate in discontinuous conduction mode in order to achieve soft switching for switches and diodes. The directly coupled inductors are utilized to reduce the number of magnetic components and decrease the input current ripple. A 500-W interleaved SEPIC PFP prototype is designed to verify the benefits of this converter. The experimental results show that the converter can maintain high efficiency over a wide range of dc-link voltage.

This paper proposes a multilevel flying capacitor dc/dc boost converter (FCBC) with a small capacitance of the flying capacitor for the reduction of converter size. In this paper, the design methods for the boost inductor and the flying capacitor in the n -level FCBC are principally and experimentally confirmed. Furthermore, the boost inductor is designed based on maximum product of voltage-time, regardless the number of level. Meanwhile, the minimum capacitance of the flying capacitor is designed based on the maximum switching device voltage stress, regardless of the output voltage ripple influences. Moreover, the achieved maximum efficiency of the designed three-level FCBC is 98.5% at the output power of 1 kW. Finally, the effectiveness of small capacitances of the flying capacitor in the three-level and five-level FCBCs is analyzed. The characteristics of the distorted voltage across the input voltage source and the boost inductor, and the distorted current to the output side (output capacitor and load) are investigated with several capacitances of the flying capacitors in the three-level and five-level FCBCs. As a result, it is experimentally confirmed that the distorted voltage is drastically reduced by increasing the number of level. Besides, the distorted current is almost the same although the number of level is increased. Therefore, based on the experimental results, it is shown that small capacitance of the flying capacitor can be used in the n -level FCBC without compromising the stability of converter operation.

One of the most significant reliability issues in switching-mode power supplies is electrolytic capacitor degradation caused by aging. This paper proposes an output voltage transient analysis method to detect capacitor wear-out at the output stage of a step-down dc–dc converter. Changes in the converter output voltage dynamics are evaluated by analyzing the output voltage step response with respect to a decrease in the capacitance. The sensitivity of the method is assessed with respect to parameter variations using an equivalent main circuit model. The feasibility of the presented method is verified by experimental tests using a converter prototype. The results show that the presented method is practical and adequate for detecting capacitor degradation in various operating conditions.

This paper details the modeling and development of an improved controller design for a dc flywheel energy storage system (FESS) driving circuit. The driving system is based on a bidirectional buck–boost converter. The modeling of this converter including the parasitic resistances for all the components was carried out. In this model, the equivalent circuit of the machine was integrated in the converter state-space model for improved accuracy and controllability. The system has two operating modes; when the FESS is charging, the converter operates in the buck mode. A controller was designed to regulate the charging rate through controlling the machine’s terminal voltage. In the discharging mode, the converter operates in the boost mode. A current controller takes over to control the injected current from the machine to the dc bus. The detailed design of both control loops was identified. Simulation results show the accuracy of the derived model and the enhanced performance of the FESS. Further, it is shown that the reversal of power-flow direction was performed seamlessly. A hardware prototype of the converter was implemented and the effectiveness of the developed system was experimentally verified. The experimental results are in excellent agreement with the simulation.

Recently, voltage-source converter (VSC)-based high-voltage dc (HVDC) transmission systems have gained more attention. In this paper, a control method for a modular VSC-based HVDC transmission system with high-frequency isolation referred to as high-frequency isolated modular converter is proposed. In the high-frequency isolated modular converter configuration, several floating dc capacitors in all three phases are connected in series, and voltage balancing control of these floating dc capacitors is required. In this paper, an appropriate control structure with the capacitor voltage balancing controller is proposed. The proposed control scheme consists of three layers to control terminal dc bus voltage and balance dc capacitor voltages of each building block. Detailed PSCAD simulation results are presented to evaluate the performance of high-frequency isolated modular converter. Controller hardware-in-the-loop simulation of the high-frequency isolated modular converter is also performed by real-time digital simulator (RTDS), and RTDS results are presented to verify the control structure. Finally, laboratory-scale experimental results are presented to validate the proposed control method.

A single-phase bridgeless Cuk ac/dc power factor correction (PFC) rectifier with positive output voltage is proposed in this paper. For low output voltage product applications, the rectifier is designed to convert high input voltage to low output voltage. Due to no bridge diodes required and thus decreased input conduction losses, the proposed rectifier efficiency can be improved. The proposed rectifier operates in discontinuous conduction mode, and the current-loop circuit is hence not needed. In addition, only a single switch is used in the rectifier to simplify the control circuit design. A simple translation method to have the positive output voltage in the Cuk converter is presented in the rectifier to reduce the component counts and the cost. The operational principles, steady-state analysis, and design procedure of the proposed rectifier are addressed in detail in this paper. Simulation and experimental results obtained from a 150-W rated prototype circuit with input of 90–130 Vrms, 60 Hz, and output of 48 Vdc have verified the validity of the proposed rectifier.

This paper proposes a new isolated three-port bidirectional dc–dc converter for simultaneous power management of multiple energy sources. The proposed converter has the advantage of using the least number of switches and soft switching for the main switch, which is realized by using an inductor–capacitor–inductor ( $LCL$ ) -resonant circuit. The converter is capable of interfacing sources of different voltage–current characteristics with a load and/or a dc microgrid. The proposed converter is constructed for simultaneous power management of a photovoltaic (PV) panel, a rechargeable battery, and a load. Simulation and experimental results show that the proposed converter is capable of maximum power point tracking control for the PV panel, when there is solar radiation, and controlling the charge and discharge of the battery, when there is surplus energy and power deficiency with respect to the load, respectively.

Similar to other major electrical apparatuses, the reliability and stability of the dc network is becoming the most important issue when using the voltage-source-converter-based multiterminal dc (VSC-MTDC) system for offshore wind power integration. A coordinated control strategy of VSC-MTDC named master–auxiliary is proposed by combining the advantages of the voltage margin and voltage droop control. This strategy has three advantages. First, the master converter station with the constant dc voltage control can provide reference to the system dc voltage and is helpful for the stabilization of dc voltage. Second, the integrated control of the dc voltage in both master and auxiliary converter stations are helpful for providing adequate active power control (APC) and restraining large power variation. Third, the APC converter station can serve as a backup for the dc voltage control in abnormal conditions. In order to guarantee the reliability and stability of the system under various operating conditions, this paper introduces the priority of dc voltage control to the coordination control strategy. Moreover, a parameter optimizing method of controllers for this strategy is also proposed. Finally, the effectiveness of the master–auxiliary control is verified by simulations under normal and abnormal conditions.

A new prototype of a zero voltage soft-switching (ZVS) utility frequency ac (UFAC) to high-frequency ac (HFAC) resonant power converter for induction heating (IH) applications is presented in this paper. The series resonant ac-ac converter proposed herein can process the frequency conversion without any diode bridge rectifier (DBR), thereby reducing the relevant conduction power losses. In addition, power factor correction (PFC) can be naturally achieved by the inductor-based boost half-bridge(BHB) circuit with the non-smoothed dc (NSDC)-link. The operation principle together with a IH load power regulation scheme is described, and the converter performances including ZVS operations and PFC are demonstrated in an experiment with a 3.0kW–30 kHz prototype by comparing with the previously developed converter. Finally, the feasibility of the proposed ac-ac converter is evaluated from a practical point of view.

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.

A novel multiport dc–dc converter with a coupling magnetic inductor is analyzed and designed. The proposed circuit integrates two multiphase converters and one isolated dc–dc converter. These converters can be controlled independently in one circuit by adjusting the duty ratio and phase angle difference. There are four dc ports in the circuit, and the dc power can be delivered multidirectionally among the four dc ports. In this paper, a 1.5-kW prototype of the multiport converter was constructed and successfully operated under full power. The experimental results confirm the theoretical analysis, and the conversion efficiency is above 90% over a wide range of output power. In addition, an example of a multifunctional power conversion system using the multiport converter is demonstrated.

This paper presents a power decoupling method based on a four-switch three-port dc/dc/ac converter in dc microgrid. The proposed topology has three interfaces which can be connected with a dc source, a capacitor, and an ac port. With a corresponding power flow control method, this converter can decouple the low-frequency ripple power which is necessary for the ac port and undesirable for the dc source with small capacitor. The proposed topology is compact and cost-effective because, compared with the H-bridge inverter, no extra switches or devices are required. With the model of the proposed dc/dc/ac converter, a power control method with two inductors' current control is presented for power decoupling. In addition, the control parameters are designed as well. Experimental results on the laboratory prototype verified the feasibility of the proposed topology and the designed power control method.

This paper presents a novel dc–dc converter configuration, which successfully integrates two technologies, including a switched capacitor and a switched coupled inductor, into one converter. By adopting a coupled inductor to charge a switched capacitor, the voltage gain can be effectively increased, and the turns ratio of the coupled inductor can be also reduced. Not only lower conduction losses but also higher power conversion efficiency is benefited from a lower part count and lower turns ratios. The proposed converter is simply composed of six components, which can be further derived to varied converters for different purposes, such as a bidirectional converter. The operating principle and steady-state analysis are discussed in this paper. A 250-W laboratory hardware prototype is completed and verified. The voltage gain is up to 11. The highest efficiency is 97.2%, and the full-load efficiency is kept at 93.6%.

This paper presents a new nonisolated buck/boost-type multilevel dc-dc converter suitable for high-power and medium/high-voltage application. The main features of the proposed topology are as follows: low voltage across the semiconductors, low switching losses, and reduced volume of the output filter. The theoretical analysis is carried out for a five-level bidirectional structure of the proposed converter, operating in Buck mode. The proposed topology presents some capacitors, and their voltage must be balanced for proper operation of the converter. Thus, a capacitor voltage balancing active control using a feedforward technique is proposed and analyzed in detail. In order to validate the theoretical analysis, a prototype with 10 kW output power capability, 1.3 kV to 800 V input-to-output voltage, and 20 kHz of switching frequency was built and experimented. The results attest the advantages of the new dc-dc topology, as well as the new capacitor voltage control technique.

This paper presents a new bidirectional dc-dc converter with a high conversion ratio for renewable energy systems. The coupled-inductor technique is used to achieve a high conversion ratio with very simple control circuits. In discharging mode, the converter acts as a two-stage boost converter, controlling one power switch to achieve high-voltage step-up conversion. In charging mode, the converter acts as two cascaded buck converters that control two power switches simultaneously to achieve high-voltage step-down conversion. The operating principles and analysis of the steady-state characteristics are discussed in great detail. Finally, a 24-V/200-V prototype circuit with output power of 200 W is implemented to verify the feasibility of the proposed converter. The maximum efficiency levels in discharging and charging modes are about 94.3% and 91.6%, respectively.

This paper introduces a novel isolated hybrid resonant converter with smooth transition between multiple operating modes. With the simple addition of a bidirectional ac switch, the highly-efficient series resonant converter operating in the discontinuous conduction mode (DCM) is combined with a phase-shifted full-bridge buck converter and a pulse width modulated (PWM) boost converter in order to provide high power conversion efficiency over a wide input-voltage operating range utilizing a simple topology and simple control techniques. First, the topology is introduced and the converter's operating modes are discussed. Next, closed-loop input-voltage controllers are designed for the different operating modes and a smooth transition technique is introduced using a two-carrier modulation scheme. Experimental results are provided to verify the proposed system using a 300-W prototype that achieved a 97.5% California Energy Commission (CEC) weighted efficiency with a 30-V input including all auxiliary and control losses.

This paper proposes a single-stage high-power-factor (HPF) LED driver with coupled inductors for street-lighting applications. The presented LED driver integrates a dual buck-boost power-factor-correction (PFC) ac-dc converter with coupled inductors and a half-bridge-type LLC dc-dc resonant converter into a single-stage-conversion circuit topology. The coupled inductors inside the dual buck-boost converter subcircuit are designed to be operated in the discontinuous-conduction mode for obtaining high power-factor (PF). The half-bridge-type LLC resonant converter is designed for achieving soft-switching on two power switches and output rectifier diodes, in order to reduce their switching losses. This paper develops and implements a cost-effective driver for powering a 144-W-rated LED street-lighting module with input utility-line voltage ranging from 100 to 120 V. The tested prototype yields satisfying experimental results, including high circuit efficiency (>89.5%), low input-current total-harmonic distortion ( 0.99), low output-voltage ripple (

This paper proposes a switched capacitor-based converter to drive high-power light-emitting diodes (LEDs). In contrast to conventional constant current dc drivers, the current pulse is provided by a switched capacitor. The proposed approach differs from the traditional switched-capacitor-based one, because it uses a small inductor to improve the switching behavior of the converter. Based on the charge control analysis, the effects of switching devices on the proposed converter are evidenced and evaluated. A 6 W, 24 V laboratory prototype has been implemented, while experimental results are presented and discussed to demonstrate the technical feasibility of the proposed converter applied as LED driver.

This paper proposes an adaptive interconnection and damping assignment (IDA) passivity-based controller (PBC) with a complementary proportional integral (PI) controller for dc-dc boost converters with constant power loads (CPLs). The plant is modeled as a port-controlled Hamiltonian system (PCHS). A virtual circuit that interprets the parameters of the PCHS is then derived to determine the parameters of the IDA-PBC for the system to work in the underdamping, critical-damping, and overdamping modes. Moreover, a complementary PI controller is designed to eliminate the steady-state output voltage error of the IDA-PBC caused by the load variation. Simulation studies are carried out in MATLAB/Simulink to validate the proposed control algorithm for a dc-dc boost converter with a CPL; results show that the proposed control algorithm ensures the stability and fast response of the system in different modes when the load changes. Experimental results are provided to further validate the design and simulation of the proposed control algorithm.

This paper proposes a single-stage three-phase-to-single-phase current-fed high step-up ac–dc matrix converter. The proposed converter inserts a boost-type matrix converter, which is formed by three boost inductors and six bidirectional switches, between a three-phase ac source and a Cockcroft–Walton voltage multiplier (CWVM). By using this topology associated with power factor correction technique, the proposed converter not only achieves almost unity power factor and sinusoidal input currents with low distortion but also obtains high voltage gain at the output end. Moreover, the matrix converter generates an adjustable-frequency and adjustable-amplitude current, which injects into the CWVM to regulate the dc output voltage and smooth its ripple. With this flexible injection current, the performance of the proposed converter is superior to the conventional CWVM, which is usually energized by a single-phase ac source. The operation principle, control strategy, and design considerations of the proposed converter are detailed in this paper. Finally, simulation and experimental results demonstrate the claims and validity of the proposed converter.

This paper discusses a new circuit configuration and a new control method for a single-phase ac–dc converter with power factor (P.F.) correction and a power pulsation decoupling function. The proposed converter can achieve low total harmonic distortion (THD) on the input current and the power pulsation decoupling function between the input and output sides, which allows low output voltage ripple even on a small output energy buffer at the same time using an active buffer. Therefore, the proposed converter does not require large smoothing capacitors or large smoothing inductors. The buffering energy is stored by a small capacitor, which controls the variation of the capacitor voltage through the active buffer. In this paper, the fundamental operations of the proposed converter are investigated experimentally. The experimental results reveal that the input current THD is 1.44%, the rate of the output voltage ripple is 6.33%, and the input P.F. is over 99%. In addition, a maximum efficiency of over 96% is obtained for a 750-W prototype converter.

A behavioral average-circuit model that analyzes hybrid converters that include a switched inductor and switched capacitors is presented. The model can be used to calculate or to simulate the average static, dynamic, and small-signal responses of hybrid converters. The model is valid for all operation modes of the switched capacitor converters (SCCs) operating in the continuous and discontinuous conduction modes of the switched inductor converter and is compatible with circuit simulators that include dependent sources. The model was verified with simulations and experimentally. The experimental converter included a boost converter followed by a ×3 SCC. Good agreement was found between the behavior of the proposed average model, full circuit simulations, and experimental results.

This paper proposes a family of hybrid converter topologies which can supply simultaneous dc and ac loads from a single dc input. These topologies are realized by replacing the controlled switch of single-switch boost converters with a voltage-source-inverter bridge network. The resulting hybrid converters require lesser number of switches to provide dc and ac outputs with an increased reliability, resulting from its inherent shoot-through protection in the inverter stage. Such multioutput converters with better power processing density and reliability can be well suited for systems with simultaneous dc and ac loads, e.g., nanogrids in residential applications. The proposed converter, studied in this paper, is called boost-derived hybrid converter (BDHC) as it is obtained from the conventional boost topology. The steady-state behavior of the BDHC has been studied in this paper, and it is compared with conventional designs. A suitable pulse width modulation (PWM) control strategy, based upon unipolar sine-PWM, is described. A DSP-based feedback controller is designed to regulate the dc as well as ac outputs. A 600-W laboratory prototype is used to validate the operation of the converter. The proposed converter is able to supply dc and ac loads at 100 V and 110 V (rms), respectively, from a 48-V dc input. The performance of the converter is demonstrated with inductive and nonlinear loads. The converter exhibits superior cross-regulation properties to dynamic load-change events. The proposed concept has been extended to quadratic boost converters to achieve higher gains.

Incorporating a medium-voltage dc (MVDC) integrated power system is a goal for future surface combatants and submarines. In an MVDC shipboard power system, dc/dc converters are commonly employed to supply constant power to electric loads. These constant power loads have a characteristic of negative incremental impedance, which may cause system instability during disturbances if the system is not properly controlled. This paper proposes a sliding-mode duty-ratio controller (SMDC) for dc/dc buck converters with constant power loads. The proposed SMDC is able to stabilize the dc power systems over the entire operating range in the presence of significant variations in the load power and input voltage. The proposed SMDC is validated by both simulation studies in MATLAB/Simulink and experiments for stabilizing a dc/dc buck converter with constant power loads. Simulation studies for an MVDC shipboard power system with constant power loads for different operating conditions with significant variations in the load power and supply voltage are also provided to further demonstrate the effectiveness of the proposed SMDC.

This paper proposes a new converter for photovoltaic (PV) water pumping or treatment systems without the use of chemical storage elements, such as batteries. The converter is designed to drive a three-phase induction motor directly from PV energy. The use of a three-phase induction motor presents a better solution to the commercial dc motor water pumping system. The development is oriented to achieve a more efficient, reliable, maintenance-free, and cheaper solution than the standard ones that use dc motors or low-voltage synchronous motors. The developed system is based on a current-fed multiresonant converter also known as resonant two-inductor boost converter (TIBC) and a full-bridge three-phase voltage source inverter (VSI). The classic topology of the TIBC has features like high voltage gain and low input current ripple. In this paper, it is further improved with the use of a nonisolated recovery snubber along with a hysteresis controller and the use of a constant duty cycle control to improve its efficiency. Experimental results show a peak efficiency of 91% at a rated power of 210 W for the dc/dc converter plus the three-phase VSI and a peak efficiency of 93.64% just for the dc/dc converter. The system is expected to have a high lifetime due to the inexistence of electrolytic capacitors, and the total cost of the converter is below 0.43 U$/Wp. As a result, the system is a promising solution to be used in isolated locations and to deliver water to poor communities.