Publications associées à Varistance

3D Printing of Customizable Transient Bioelectronics and Sensors

Transient electronics have emerged as a new category of devices that can degrade after their functional lifetime, offering tremendous potential as disposable sensors, actuators, wearables, and implants. Additive manufacturing methods represent a promising ...

2024

Phase Shift Angle Segmentation Modulation for Soft-Switching Medium-Voltage DAB Converter With Series-Connected SiC MOSFETs

Chengmin Li, Rui Lu, Heng Fang

The medium-voltage (MV) dual active bridge (DAB) converter with series-connected SiC (S-SiC) MOSFETs is a promising solution for high-power-density isolated dc/dc converter. To improve the voltage sharing and reliability of S-SiC, relatively large snubber ...

Ieee-Inst Electrical Electronics Engineers Inc2024

Protection unit for wide bandgap power switching device and method for operating the wide bandgap power switching device

Drazen Dujic, Chengmin Li

The invention relates to a method for operating a power switching device, particularly a wide bandgap power switching device, in a power application, particularly in a converter, comprising the steps of:- checking (S2) a transient voltage of or related to ...

2023

ICRH assisted breakdown study on JET

Benoît Labit, Thomas Binderup Jensen, Haomin Sun

Ion cyclotron (IC) wave assisted breakdown has the potential to increase the robustness of plasma initiation during the ITER pre-fusion operation phase. Studies were performed at JET at ITER relevant loop electric field, E-loop ? 0.33 Vm(-1), and a range o ...

IOP Publishing Ltd2023

Zinc hybrid sintering for printed transient sensors and wireless electronics

Danick Briand, Nicolas Francis Fumeaux

Transient electronics offer a promising solution for reducing electronic waste and for use in implantable bioelectronics, yet their fabrication remains challenging. We report on a scalable method that synergistically combines chemical and photonic mechanis ...

2023

A Data-Driven Fault Location Algorithm Based on the Electromagnetic Time Reversal in Mismatched Media

Mario Paolone, Zhaoyang Wang, Zhe Chen

The classical electromagnetic time reversal (EMTR) fault location method in power systems can be time consuming, especially when a high location accuracy is desired. To cope with this issue, the concept of EMTR in mismatched media has recently been introdu ...

2021

Three-Dimensional FDTD-Based Simulation of Induced Surges in Secondary Circuits Owing to Primary-Circuit Surges in Substations

Farhad Rachidi-Haeri, Marcos Rubinstein, Akiyoshi Tatematsu

Currently, plenty of sensitive electronic devices are installed in secondary circuits in substations and power plants. Electronic devices may malfunction and become damaged owing to electromagnetic disturbances caused mainly by lightning surges. To protect ...

2021

Simulation of High-Frequency Transients in Overhead Lines Including Frequency-Dependent Soil Parameters: an FDTD Aproach

Farhad Rachidi-Haeri, Rafael Silva Alipio

This paper investigates the effect of frequency-dependent soil parameters on the simulation of electromagnetic transients on overhead lines, based on the application of the FDTD method to solve the telegrapher’s equations. The ground return impedance is ca ...

2021

Figures-of-Merit of Lateral GaN Power Devices: modeling and comparison of HEMTs and PSJs

Elison de Nazareth Matioli, Luca Nela, Catherine Erine, Maria Vittoria Oropallo

In this work, we propose a simple and yet accurate physical model to describe the figures-of-merit (FOMs) of lateral GaN power devices. While the performance limit of vertical devices is well understood, the FOMs of lateral devices are not properly describ ...

2021

Four Quadrant Bus-Tie Switch for Protection of Shipboard Power Systems

Drazen Dujic, Gabriele Ulissi

The desire to increase the voltage of DC shipboard power distribution networks to the medium voltage level derives from the pressure to reduce the operating costs of such systems by increasing their efficiency. Solid state bus-tie switches are accepted to ...

IEEE2020

Scalable Solid State Bus Tie Switch for Flexible Shipboard Power Systems

Drazen Dujic, Gabriele Ulissi

The need to increase efficiency and reduce operating cost of shipboard DC power distribution networks results in a desire to increase the operating voltage of such installations to the medium voltage levels. Devices such as solid state bus-tie switches are ...

2020

On Power Scalability of Modular Multilevel Converters: Increasing Current Ratings Through Branch Paralleling

Drazen Dujic, Stefan Milovanovic

The modular multilevel converter (MMC) presented in Figure 1 found its place within highvoltage and medium-voltage (MV) applications owing to the possibility of effortlessly meeting the imposed voltage requirements by stacking the so-called submodules (SMs ...

2020

The effect of SO2 on the Ni-YSZ electrode of a solid oxide electrolyzer cell operated in co-electrolysis

Jan Van Herle, Stefan Diethelm, Guillaume Jeanmonod

In this work, the effect of sulphur poisoning of the Ni-YSZ electrode of an SOEC operated in co-electrolysis mode was investigated. Short-term tests with exposure up to 5 ppmv of SO2 were performed at OCV and under polarization (0.25 A cm−2). The two-stage ...

2020

Fully Soft-Switched High Step-Up Nonisolated Three-Port DC-DC Converter Using GaN HEMTs

Marco Mattavelli, Elison de Nazareth Matioli, Georgios Kampitsis, Rasoul Faraji

In this article, a soft-switched nonisolated high step-up multi-input dc-dc converter is proposed. The proposed converter has overcome the hard switching problem of the conventional boost three port converter (boost-TPC) by providing zero-voltage-switching ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2020

Design and Control of a KE (Kinetic Energy) - Compensated Gravitational Energy Storage System

Alfred Rufer

A gravitational energy storage device is described where the kinetic energy to recover while braking a vertically moving mass is compensated by an auxiliary storage device based on supercapacitors. The characteristic power surge occurring by a fast decreas ...

IEEE2020

Output-Capacitance Hysteresis Losses of Field-Effect Transistors

Elison de Nazareth Matioli, Armin Jafari, Palliyage Srilak Nirmana Perera, Luca Nela, Georgios Kampitsis

Resonant-type power converters are supposed to generate zero switching losses during soft-switching operation. In recent research, unexpected switching losses were reported in these converters, which were attributed to a large-signal hysteresis observed in ...

IEEE2020

Multi-level high-voltage power supply for dea application

Yves Perriard, Yoan René Cyrille Civet, Morgan Almanza, Lucas Pniak, Lucas Depreux

In order to reap the benefits of Dielectric Elastomer Actuator (DEA) high energy density, the electronics powering the actuator should be as small as possible. Knowing that only a small fraction of the energy delivered to DEAs is effectively converted into ...

2019

High voltage switch for compact bidirectional dc-dc converter driving dielectric electroactive polymer actuators

Yves Perriard, Yoan René Cyrille Civet, Morgan Almanza, Raphaël Johannes Charles Mottet, Lucas Pniak

Driving DEAs requires time-varying high voltage power supplies, up to 18kV for 200um polymer layers. HV amplifiers are commonly used but bulky and expensive. Designing embedded actuators requires compact and efficient powersupplies. Furthermore, only a lit ...

2019

Origin of apparent light-enhanced and negative capacitance in perovskite solar cells

Wolfgang Richard Tress, Ulf Anders Hagfeldt, Firouzeh Ebadi Garjan

So-called negative capacitance seems to remain an obscure feature in the analysis of the frequency-dependent impedance of perovskite solar cells. It belongs to one of the puzzling peculiarities arising from the mixed ionic-electronic conductivity of this c ...

Springer2019

Inverse Problems and Optimal Power Flow in Active Distribution Networks

Cong Wang

During the last decade, distribution networks have experienced essential changes driven by the integration of renewable-energy sources, batteries, electric-vehicle charging stations, etc. This results in not only opportunities, but also operational problem ...

EPFL2019