Please enter the words you want to search for:

EPE 2007 - Subtopic 13-3 - LS: Fuel Cells
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 13: 'Electrical energy generating systems, renewable energy systems' > EPE 2007 - Subtopic 13-3 - LS: Fuel Cells
	[return to parent folder]
	Clamping for current-fed dc/dc converters with recovery of clamping energy in fuel cell inverter systems   By MOHR Malte; FUCHS Friedrich W.	[View]   [Download]
Abstract: Current-fed dc/dc converters like current-fed full bridge converters or boost converters with autotransformer, which are appropriate solutions in medium power fuel cell systems, need clamping circuits to protect the main semiconductors against overvoltages. Depending on the stray inductances of the inductive components the power drawn by the clamping circuit can be up to 5-10 \% of the converter's transferred power. This paper describes methods to recover the energy of the clamping circuit (sometimes called "active clamping") and to feed it directly into the converter's secondary side. These methods are shown for the current fed full bridge converter and the boost converter with autotransformer. The operating behaviour of the clamping circuits is shown and analysed. Also the semiconductor losses of the switches in the clamping circuit are derived for both converters. The general operating behaviour and the analysis is verified by simulation results and by practical results of two laboratory setups with a rated power of 20 kW. Practical issues of the clamping circuit like the non-ideal reverse recovery behaviour of the MOSFET's body-diode are also covered in this paper.
	Design and control of a Fuel Cell DC/DC Converter for Embarked Applications   By BERTHON Alain; NARJISS Abdellah; GUSTIN Frédéric; DEPERNET Daniel; HISSEL Daniel	[View]   [Download]
Abstract: This work consists in a theoretical and practical study of a DC/DC converter designed to be coupled to a fuel cell stack in transport applications. It also proposes monitoring and control of the whole system using a DSP (Digital Signal Processor) controller.
	Design Considerations of a Voltage-fed Full Bridge DC-DC Converter with High Voltage Gain for Fuel Cell Applications   By MERTENS Axel; AVERBERG Andreas	[View]   [Download]
Abstract: Fuel cells in the kW range have a high output current and low output voltage. To connect them to the mains, a dc-dc converter with a high voltage gain and an inverter are needed. In this paper an investigation of the voltage-fed full bridge dc-dc converter with high voltage gain is presented. A detailed analysis of the different operating modes, the semiconductors' current and voltage stress, the switching losses and the transformer stress is given. The influence of diverse parameters like winding ratio, leakage inductance and output inductance on the operating behaviour, hence voltage gain and efficiency is stated out. The analytical results are compared with measurements taken from a 1.2 kW prototype. Finally, design criteria for the dc-dc converter are given to realise a high voltage gain and high efficiency.