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This paper proposes a new design with magnetizing inductance to achieve extended range soft switching of a current-sharing three-phase ac-link active-clamped zero-voltage switching (ZVS) current-fed dc/dc converter for low-voltage dc sources, i.e., battery, fuel cells, etc. The paper explains steady-state operation and presents steady-state analysis and design including magnetizing inductance effect. The proposed converter maintains ZVS of all power semiconductor devices over wide range of load and source voltage. Current sharing results in reduced peak currents and conduction losses. The proposed converter combines the merits of three-phase configuration with zero-current switching of rectifier diodes, making it a competitive topology in the area of power supplies/converters for medium power applications requiring high-voltage amplification ratio. Simulation results using PSIM 9.0 are given to verify the proposed analysis and design. An experimental converter prototype rated at 300 W has been designed, developed, and tested in the laboratory to verify and demonstrate the converter performance over wide variations in input voltage and output power for fuel cell applications. [ABSTRACT FROM PUBLISHER]

Power electronics solutions based on multiple converter configurations offer cost-effective solutions by integrating a number of components at input or output power stages. This paper proposes a new multiinput isolated three-level converter for renewable and sustainable energy systems adopting high dc link voltage. Multiple dc sources are integrated to the three-level dc/dc converter before the isolation stage, resulting in reduced part-count, determining dc link voltage level and allowing flexibility in transformer design. The proposed architecture eliminates two boost switches which are present in the two-stage counterpart. The input inductors are operated in discontinuous conduction mode; thus, power can be shared between input sources through proper selection of input inductors. A low voltage prototype has been designed to serve as a proof of concept. [ABSTRACT FROM PUBLISHER]

This paper provides an analysis of a three-phase dual active bridge (DAB) topology used as high-power-density dc–dc converter for railway applications. The three-phase DAB is analyzed concerning the current intervals, the output power, and soft-switching region, including the impact of zero-voltage switching capacitors. Furthermore, two measures are proposed to achieve soft-switching in the entire operating range, being auxiliary inductors and a straightforward switching strategy called the burst mode. Optimal component values are calculated to minimize losses in the complete operating range and to assess which measure is best suited. A prototype with the specifications acquired from the application has been built, yielding an efficiency of $95.6\%$ at a nominal output power of 80\, {\rm kW}. [ABSTRACT FROM AUTHOR]

The paper discusses two approaches to multiphase nonisolated dc-dc converter design. An approach based on independent phases is directly compared to an approach using coupled phases. The comparison is performed through theoretical analysis of respective conversion functions, input and output filter requirements, and required input inductor size. Three-dimensional (3-D) high-power-density computer aided design (CAD) models and full-scale 56 kW prototypes based on both approaches were designed, built, and experimentally compared. As expected, the approach with independent phases has a considerable advantage regarding the low-power conversion efficiency where the efficiency can be up to 2% higher than with the coupled approach. On the other hand, the design with coupled inductors can reach power density as high as two times that of the independent phase design (87 kW/L versus 44.2 kW/L). Therefore, the use of coupled inductors may be very beneficial for space critical applications. In case of the electric vehicle power train, both factors may be very important and the suitable approach should be chosen based on system design priorities. [ABSTRACT FROM AUTHOR]

The integration of photovoltaic (PV) modules in buildings causes problems with shadows that can strongly reduce the energy produced by these systems. Moreover, most PV modules are designed for stand-alone applications that have output voltage adapted to lead batteries. Indeed, this historical sizing of PV modules can be discussed in the case of grid-connected systems. In this paper, a cascaded dc/dc converter based on boost chopper is proposed. First, the advantages and the limits of this topology will be shown. Second, this topology will be optimized to maximize the efficiency or minimize the volume. The originality of this optimization is that the converters' parameters and the arrangement of the PV cells are variable parameters. Indeed, the optimization is done on the entire system. To realize these optimizations, semiempiric models of losses and volumes of different components of a boost chopper were developed. The optimization uses a successive quadratic programming algorithm. Considering the optimization results over the whole range of the specifications, a flexible solution is developed and experimental results are presented. Finally, optimized topologies connected to several PV are evaluated at different situations of typical shadows. [ABSTRACT FROM AUTHOR]

This paper presents an alternative to the traditional dc-dc converter interfacing the battery with the inverter dc bus in plug-in hybrid electric vehicle (HEV) traction drives. The boost converter used in commercial HEVs meets with obstacles when it comes to upgrading the power rating and achieving high efficiency while downsizing the converter. A four-level flying-capacitor dc-dc converter is explored that can overcome these drawbacks by dramatically reducing the inductance requirement. A special case of the four-level converter, the 3X dc-dc converter, operates at three discrete output/input voltage ratios, thus further reducing the inductance requirement to a minimal value (almost zero). When further compared to its switched-capacitor dc-dc converter counterparts, the 3X dc-dc converter can be operated at variable output/input voltage ratios without sacrificing efficiency, and it lowers the capacitance requirement by utilizing the parasitic inductance. The operating principle, current ripple analysis, the transient control to limit the inrush current, and power loss analysis are introduced. Experimental results of a 55-kW prototype are provided to demonstrate the principle and analysis of this topology. [ABSTRACT FROM AUTHOR]