Armin Jafari

Cette personne n’est plus à l’EPFL

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Publications associées (31)

97.4%-Efficient All-GaN Dual-Active-Bridge Converter with High Step-up High-Frequency Matrix Transformer

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

In this work, we demonstrate a state-of-the-art high step-up/down dual-active-bridge (DAB) converter designed with GaN transistors, to achieve a high efficiency and large power-density. A quasi-planar matrix transformer with high step-up/down ratio is demo ...

2020

Output Capacitance Losses in Wide-Band-Gap Transistors: A Small-Signal Modeling Approach

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

Wide-band-gap (WBG) power semiconductor devices are gaining an increasing interest in power circuits, as they exhibit a low specific ON-resistance (RON) while providing a high blocking voltage. The energy dissipation corresponding to resonantly charging an ...

IEEE2020

Comparison of Wide-band-gap Technologies for Soft-Switching Losses at High Frequencies

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

Soft-switching power converters based on wide-band-gap (WBG) transistors offer superior efficiency and power density advantages. However, at high frequencies, loss behavior varies significantly between different WBG technologies. This includes losses relat ...

2020

Coss Loss Tangent of Field-Effect Transistors: Generalizing High-Frequency Soft-Switching Losses

Elison de Nazareth Matioli, Armin Jafari, Palliyage Srilak Nirmana Perera, Mohammad Samizadeh Nikooytabalvandani, Luca Nela

The dissipated energy (Ediss) related to the resonant charging/discharging of a transistor output capacitance, becomes a dominant loss factor for power converters operating in the MHz range. A recent work has introduced a small-signal measurement method to ...

2020

Measurement of Large-Signal Coss and Coss Losses of Transistors Based on Nonlinear Resonance

Elison de Nazareth Matioli, Armin Jafari, Palliyage Srilak Nirmana Perera

In this letter, we present a new measurement technique to evaluate the large-signal output capacitance ( COSS ) of transistors as well as the COSS energy dissipation ( EDISS ), based on the nonlinear resonance between a known inductor and the output capaci ...

2019

On-Chip High-Voltage Sensors Based on Trap-Assisted 2DEG Channel Control

Elison de Nazareth Matioli, Armin Jafari

In this work, we present a new device concept for compact high-voltage sensing with high-impedance input port, consisting of an AlGaN/GaN high-electron-mobility channel controlled by trapped carriers generated by a metallic electrode. The high-voltage appl ...

Institute of Electrical and Electronics Engineers2019

Enhanced DAB for Efficiency Preservation using Adjustable-Tap High-Frequency Transformer

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

Efficient DC-DC power-conversion with wide-span voltage-regulation is crucial to a sustainable and robust power electronics system. Dual-active-bridge (DAB) offers straight-forward regulation and its transformer enables voltage step-up/down required for ma ...

2019

GaN Transistors for Miniaturized Pulsed-Power Sources

Elison de Nazareth Matioli, Armin Jafari

2019

On the Dynamic Performance of Laterally Gated Transistors

Elison de Nazareth Matioli, Giovanni Santoruvo, Armin Jafari, Catherine Erine, Mohammad Samizadeh Nikooytabalvandani

Laterally gated transistors have been proposed as an innovative device architecture in which a semiconducting channel is controlled by side gates. In this sense, the gate can either be in contact with the sidewalls or be separated by a gap. In the latter c ...

Institute of Electrical and Electronics Engineers2019

New Insights on Output Capacitance Losses in Wide-Band-Gap Transistors

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

The low ON-resistance of wide-band-gap (WBG) transistors is a key feature for efficient power converters, however, the anomalous loss in their output capacitance (COSS) severely limits their performance at high switching frequencies. Characterizing COSS-lo ...

2019

High Step-Up High-Frequency Zero-Voltage Switched GaN-Based Single-Stage Isolated DC-DC Converter for PV Integration and Future DC Grids

Elison de Nazareth Matioli, Armin Jafari

2018

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