Publications de Armin Jafari | EPFL Graph Search

Switching losses in power devices: From dynamic on resistance to output capacitance hysteresis

Elison de Nazareth Matioli, Remco Franciscus Peter van Erp, Hongkeng Zhu, Armin Jafari, Palliyage Srilak Nirmana Perera

In this paper, we review some of the main methods to characterize on-state and off-state losses in wide-band-gap devices under switching conditions. In the off-state, we will discuss about losses related to charging and discharging the output capacitance i ...

IEEE2023

Measurement of WBG-based power supplies

Elison de Nazareth Matioli, Hongkeng Zhu, Armin Jafari

This paper discusses different measurement methods to evaluate the efficiency of WBG-based power supply solutions, including electrical measurement methods and their verification with calorimetric methods, and compares the performance of Si-based and GaN-b ...

IEEE2023

Hard-Switching Losses in Power FETs: The Role of Output Capacitance

Elison de Nazareth Matioli, Armin Jafari, Palliyage Srilak Nirmana Perera, Reza Soleiman Zadeh Ardebili

For certain field-effect transistors (FETs) in soft-switching operation, the large-signal behavior of their output capacitance ( Co ) has shown to deviate considerably from the datasheet values. This can have a significant effect on hard-switching losses i ...

2021

Enhanced-DAB Converter: Comprehensive Design Evaluation

Elison de Nazareth Matioli, Armin Jafari, Mohammad Samizadeh Nikooytabalvandani, Furkan Karakaya

Soft switching in dual-active-bridge (DAB) converters enables their efficient operation at high frequencies, where the reduction in the size of magnetic components could result in ultra-high power densities. Nonetheless, losing soft-switching at high frequ ...

IEEE2021

Pushing the Limits of Efficiency and Power Density in High-Frequency Power Conversion Based on Wide-Band-Gap Technologies

Armin Jafari

The emergence of wide-band-gap (WBG) power transistors with low conduction losses and high-speed switching speeds has paved the way for more-than-ever efficient power electronics systems and huge energy saving potentials. Likewise, power density- the ratio ...

EPFL2021

Resonances on GaN-on-Si Epitaxies: A Source of Output Capacitance Losses in Power HEMTs

Elison de Nazareth Matioli, Armin Jafari, Minghua Zhu, Riyaz Mohammed Abdul Khadar, Mohammad Samizadeh Nikooytabalvandani

GaN-on-Si high-electron-mobility transistors (HEMTs) exhibit excellent properties for efficient power conversion. Nevertheless, a considerable energy loss associated with the charging and discharging of the output capacitance (COSS) in these transistors se ...

Institute of Electrical and Electronics Engineers2021

Kilowatt-range Picosecond Switching Based on Microplasma Devices

Elison de Nazareth Matioli, Remco Franciscus Peter van Erp, Armin Jafari, Mohammad Samizadeh Nikooytabalvandani

Plasma formation in micro- and nano-scales enables an ultrahigh-dv/dt picosecond switching in an integrated circuit form factor. Such on-chip plasma devices could provide a transformative approach to achieving high-power levels at very high frequencies, fa ...

Institute of Electrical and Electronics Engineers2021

Comparison of Wide-Band-Gap Technologies for Soft-Switching Losses at High Frequencies (vol 35, pg 12595, 2020)

Elison de Nazareth Matioli, Halil Kerim Yildirim, Armin Jafari, Palliyage Srilak Nirmana Perera, Reza Soleiman Zadeh Ardebili, Mohammad Samizadeh Nikooytabalvandani

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2021

Investigation on Output Capacitance Losses in Superjunction and GaN-on-Si Power Transistors

Elison de Nazareth Matioli, Halil Kerim Yildirim, Armin Jafari, Palliyage Srilak Nirmana Perera, Mohammad Samizadeh Nikooytabalvandani

Low ON-resistance of advanced superjunction (SJ) and GaN-on-Si transistors is of great importance in power converters, however, the anomalous loss in their output capacitance (C OSS ) severely limits their performance. In this work, we use an energy-orient ...

IEEE2021

Active-Device Losses in Resonant Power Converters: A Case Study with Class-E Inverters

Elison de Nazareth Matioli, Remco Franciscus Peter van Erp, Armin Jafari, Palliyage Srilak Nirmana Perera, Jessy Anthony Ançay

Recent research has reported an undesirable OFF-state loss in high-frequency soft-switching power converters, such as resonant converters. This loss is attributed to a hysteresis loss related to the charging-discharging process of the output capacitance of ...

IEEE2021