Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.
AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.
Electroactive polymers show promising characteristic such as lightness, compactness, flexibility and large displacements making them a candidate for application in cardiac assist devices. This revives the need for quasi- square wave voltage supply switching between 0 and several kilo-Volts, that must be efficient, to limit the heat dissipation, and compact in order to be implanted. The high access resistance, associated to compliant electrodes, represents an additional difficulty. Here, a solid-state Marx modulator is adapted to cope with electroactive polymer characteristics, taking advantage of an efficient energy transfer over a sequential multistep charge/discharge process. To ensure compactness, efficiency as well as the needs of an implanted device, a wireless magnetic field based communication, and power transfer system has been implemented. This work demonstrates the benefit of this design through simulations, and experimental validation on a cardiac assist device. At a voltage of 7 kV, an efficiency of up to 88% has been achieved over a complete charge/discharge cycle.