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This paper proposes a new class of converters based on the inductive input converters for the design of a power electronic interface for fuel cell (FC) applications. After studying the half-bridge structure, two soft-switching dc-dc converters are analyzed: one operating in zero-voltage-switching (ZVS) mode and the other in zero-current-switching (ZCS) mode. The ZYS converter can overcome the drawbacks of the original structure but is more complicated. The ZCS converter cannot operate at duty cycles below 0.5, but is simpler and more suitable for FC applications. Flexible choice of components, low losses, high efficiency, and modular converter possibility are all interesting characteristics of these converters. Their operation principle and characteristics are presented in this paper. Experimental results on 2 kW converters of each structure validate the theoretical analysis. [ABSTRACT FROM AUTHOR]

In a resonant dc/dc converter, the major part of the volume is filled by passive components. Moreover, all these components have to support all the power flow. On the one hand, this leads to losses in these components and their connections and on the other hand to an important cost of the converter. Concept of integrated passive component, called inductor-capacitor-transformer (L-C-T), is now well known [1], [3], [4], [6], [8] and this paper will present a new prototype which permits to integrate in an unique part an inductor, a capacitor and a transformer. Because it uses only one core with three windings, this component will reduce the volume of the passive part of the converter. By reducing the number of connections it will, also, have a positive effect on losses. After a presentation of L-C-T components, this paper describes a design of this device, using new windings disposition. The proposed structure permits to adjust separately L and C values. Then, to validate the approach, a characterization is carried out, leading to a new model, including dielectric, iron and copper losses. [ABSTRACT FROM AUTHOR]

This paper deals with the design and the realization of an integrated isolated HF dc-to-dc converter for low-voltage and low-power conditioning applications (3.3 V and 1 W) including galvanic isolation. It is based on the 3-D integration of several elementary silicon dies in which essential components such as the inverter, the rectifier, the HF transformer, the input and output capacitors, and the output inductor have been integrated. The paper deals with the silicon integration of all these elements, with the presentation of our work being related with the state of the art. Then, it focuses on an estimate of the whole converter functional performance at 1-MHz switching frequency. Practical but partial implementation was carried out. The inverter and the rectifier are designed in CMOS technology (Austria Micro Systems 0.35 \mu\m) and have been optimized to operate at HF (1 MHz) to reduce the size of passive devices. We have monolithically integrated all that is necessary for this function. The transformer, as well as the inductor and the capacitors, is also integrated on separate silicon dies. Their integration is discussed, as well as their design and practical characterization. Based on a distributed construction, the overall converter efficiency is estimated in simulation based on practical characterizations. It appears that correct efficiency with a reasonable silicon surface and volume can be reached. [ABSTRACT FROM PUBLISHER]