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Analysis and estimation of power losses in high-power, high-frequency transformers for isolated DC/DC converters

Grzejszczak Piotr, Barlik Roman, Wolski Kornel

Archives of Electrical Engineering

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2024

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Vol. 73, nr 3

817--830

EN

The paper presents an in-depth analysis of the power losses in the windings and the cores of two different transformers as applied to a phase-shifted full bridge (PSFB) converter at the power level of 20–25 kW and the switching frequency of 50 kHz. The main difference in the construction of the considered devices was the method of winding realization as well as the shape and material of the cores. The influence of the winding geometry on the conduction losses was analyzed, and the losses in the cores were analytically estimated, taking into account the operating conditions of these elements in the full-bridge system with phase-shift modulation. Original resistive models of windings made of cooper sheets are presented. The obtained results were verified by experimental tests carried out in an isolated full-bridge DC/DC converter.

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Śp. prof. dr inż. Henryk Tunia

Barlik Roman

Wiadomości Elektrotechniczne

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2023

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R. 91, nr 6

37--38

PL

Z wielkim żalem przyjęliśmy wiadomość o śmierci prof. dr. inż. Henryka Tuni, który odszedł 5 kwietnia 2023 r., kilka dni po swoich 98. urodzinach.

3

Mathematical and simulation modeling of dual active bridge

Barlik Roman, Grzejszczak Piotr, Koszel Mikołaj

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 5

art. no. e142653

EN

The paper is a structured, in-depth analysis of dual active bridge modeling. In the research new, profound dual active bridge converter (DAB) circuit model is presented. Contrary to already described idealized models, all critical elements including numerous parasitic components were described. The novelty is the consideration of a threshold voltage of diodes and transistors in the converter equations. Furthermore, a lossy model of leakage inductance in an AC circuit is also included. Based on the circuit equations, a small-signal dual active bridge converter model is described. That led to developing control of the input and output transfer function of the dual active bridge converter model. The comparison of the idealized model, circuit simulation (PLECS), and an experimental model was conducted methodically and confirmed the high compatibility of the introduced mathematical model with the experimental one. Proposed transfer functions can be used when designing control of systems containing multiple converters accelerating the design process, and accurately reproducing the existing systems, which was also reported in the paper.

4

Wpływ obwodów odciążających na łączeniowe straty energii w przekształtnikach wysokiej częstotliwości

Grzejszczak Piotr, Czaplicki Adam, Szymczak Marek, Barlik Roman

Przegląd Elektrotechniczny

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2020

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R. 96, nr 6

93--97

PL

Niniejsza praca dotyczy analizy procesów łączeniowych w gałęzi z szybkimi tranzystorami MOSFET. Opisano podstawowe zjawiska towarzyszące szybkim procesom łączeniowym oraz zdefiniowano źródła drgań wartości chwilowych prądu i napięcia na łącznikach. Przybliżono znane z literatury sposoby ograniczania przepięć i tłumienia pasożytniczych drgań obwodu komutacyjnego. Podstawowym celem prowadzonych badań była analiza wpływu obwodów odciążających na łączeniowe straty energii, które są szczególnie istotne w przekształtnikach wysokiej częstotliwości.

EN

This work is devoted to influence of snubber circuits to the fast MOSFET switching. Basic phenomena associated with fast switching were described and sources of transistor current and voltage ringing were defined. The most popular methods of limiting overvoltage and suppressing of parasitic ringing of the MOSFET circuit were presented. The main purpose of the research was the impact of snubber circuits on MOSFET switching energy losses analysis, which are very important in high frequency converters.

5

Investigation of a High-efficiency and High-frequency 10-kW/800-V Three-phase PWM Converter with Direct Power Factor Control

Barlik Roman, Grzejszczak Piotr, Leszczyński Bernard, Szymczak Marek

International Journal of Electronics and Telecommunications

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2019

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Vol. 65, No. 4

619--624

EN

The paper presents a concept of a control system for a high-frequency three-phase PWM grid-tied converter (3x400 V / 50 Hz) that performs functions of a 10-kW DC power supply with voltage range of 600÷800 V and of a reactive power compensator. Simulation tests (in PLECS) allowed proper selection of semiconductor switches between fast IGBTs and silicon carbide MOSFETs. As the main criterion minimum amount of power losses in semiconductor devices was adopted. Switching frequency of at least 40 kHz was used with the aim of minimizing size of passive filters (chokes, capacitors) both on the AC side and on the DC side. Simulation results have been confirmed in experimental studies of the PWM converter, the power factor of which (inductive and capacitive) could be regulated in range from 0.7 to 1.0 with THDi of line currents below 5% and energy efficiency of approximately 98.5%. The control system was implemented in Texas Instruments TMS320F28377S microcontroller.