---
_id: '46269'
abstract:
- lang: eng
  text: 'State-of-the-art LLC resonant converters use MOSFETs in their inverter stage,
    which allows high switching frequencies and thus the use of compact magnetic components.
    The large parasitic output capacitance and the poor reverse-recovery behaviour
    of the inherent body diode of high-voltage (600 V) silicon MOSFETs require soft
    switching, i.e. zero-voltage switching (ZVS). Otherwise, the high turn-on switching
    losses would lead to excessive heating and ultimately to the destruction of the
    switch. Therefore, MOSFET-based LLC converters are operated in the so-called inductive
    region only, which enables ZVS. The use of robust and cost-effective IGBTs instead
    of MOSFETs is particularly advantageous for automotive applications, since in
    addition to high reliability low costs are an important objective here. Since
    IGBTs are characterized by dominant turn-off losses and generally higher switching
    losses compared to MOSFETs, the aim is to operate them with zero-current switching
    (ZCS) and at low switching frequencies below the resonance frequency. In this
    region also the voltage transfer characteristic is steeper, which qualifies for
    applications with a strongly varying input-to-output voltage ratio, such as given
    for automotive on-board DC-DC converters connecting the (high-voltage) traction
    battery with the (12 V) auxiliary battery. In this paper, a stress value analysis
    based on a switched-model simulation is used to design a ZCS LLC converter and
    take advantage of the mentioned benefits of IGBTs as well as of the steeper voltage
    transfer characteristic. Within this operation region below the resonance frequency,
    however, a new phenomenon of several current pulses occurring during a single
    switching period through the rectifier components may appear. Generally, in applications
    with high output currents a synchronous rectifier (SR) is often used to keep the
    conduction losses of the rectifier stage at a moderate level: Low-voltage MOSFETs,
    which actively need to be gated synchronously to the polarity of the current pulses,
    are employed then instead of more lossy rectifier diodes. However, standard SR
    driver ICs have been shown to be unable to properly rectify the multi-pulse output
    currents of the proposed LLC operation, resulting in high conduction losses of
    the rectifier stage. A cost-effective hardware concept is presented which ensures
    proper rectification by using standard SR-ICs that are actively overdriven by
    the converter’s central microcontroller. A 2 kW prototype for an EV on-board DC-DC
    converter was built to show the effectiveness of the method, documenting an increase
    in efficiency by up to 4.1 % compared to a purely SR-IC-based solution. Overall
    efficiency is very similar to that of a conventional (MOSFET-based) LLC converter
    so that the ZCS-operated LLC IGBT-converter represents a cost-effective alternative,
    which even shows 10 % less worst-case losses.'
author:
- first_name: Daniel
  full_name: Urbaneck, Daniel
  id: '60223'
  last_name: Urbaneck
- first_name: Frank
  full_name: Schafmeister, Frank
  last_name: Schafmeister
- first_name: Joachim
  full_name: Böcker, Joachim
  last_name: Böcker
citation:
  ama: 'Urbaneck D, Schafmeister F, Böcker J. Advanced Synchronous Rectification for
    an IGBT-Based ZCS LLC Converter with High Output Currents for a 2 kW Automotive
    DC-DC Stage. In: <i>PCIM Europe 2023</i>. ; 2023.'
  apa: Urbaneck, D., Schafmeister, F., &#38; Böcker, J. (2023). Advanced Synchronous
    Rectification for an IGBT-Based ZCS LLC Converter with High Output Currents for
    a 2 kW Automotive DC-DC Stage. <i>PCIM Europe 2023</i>. PCIM Europe 2023, Nürnberg.
  bibtex: '@inproceedings{Urbaneck_Schafmeister_Böcker_2023, title={Advanced Synchronous
    Rectification for an IGBT-Based ZCS LLC Converter with High Output Currents for
    a 2 kW Automotive DC-DC Stage}, booktitle={PCIM Europe 2023}, author={Urbaneck,
    Daniel and Schafmeister, Frank and Böcker, Joachim}, year={2023} }'
  chicago: Urbaneck, Daniel, Frank Schafmeister, and Joachim Böcker. “Advanced Synchronous
    Rectification for an IGBT-Based ZCS LLC Converter with High Output Currents for
    a 2 KW Automotive DC-DC Stage.” In <i>PCIM Europe 2023</i>, 2023.
  ieee: D. Urbaneck, F. Schafmeister, and J. Böcker, “Advanced Synchronous Rectification
    for an IGBT-Based ZCS LLC Converter with High Output Currents for a 2 kW Automotive
    DC-DC Stage,” presented at the PCIM Europe 2023, Nürnberg, 2023.
  mla: Urbaneck, Daniel, et al. “Advanced Synchronous Rectification for an IGBT-Based
    ZCS LLC Converter with High Output Currents for a 2 KW Automotive DC-DC Stage.”
    <i>PCIM Europe 2023</i>, 2023.
  short: 'D. Urbaneck, F. Schafmeister, J. Böcker, in: PCIM Europe 2023, 2023.'
conference:
  end_date: 2023-05-11
  location: Nürnberg
  name: PCIM Europe 2023
  start_date: 2023-05-09
date_created: 2023-08-02T11:27:32Z
date_updated: 2023-08-02T11:30:23Z
keyword:
- LLC Converter
- IGBT
- ZCS
- Synchronous Rectification
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10173337
publication: PCIM Europe 2023
publication_status: published
status: public
title: Advanced Synchronous Rectification for an IGBT-Based ZCS LLC Converter with
  High Output Currents for a 2 kW Automotive DC-DC Stage
type: conference
user_id: '60223'
year: '2023'
...
---
_id: '29893'
abstract:
- lang: eng
  text: Phase-shift modulated full bridge converters suffer from thermal imbalances
    of the inverter switches. The lagging leg switches are subject to larger commutation
    currents compared to those of the leading leg as the transformer current reduces
    in the freewheeling interval. Furthermore, after this interval, the energy in
    the series inductance may not be large enough to achieve zero-voltage switching
    (ZVS) for the leading leg. Both effects result in thermal imbalances. This paper
    analyzes the alternating-asymmetrical phase-shift modulation to achieve balanced
    conduction and switching losses for all four switches while showing that this
    modulation is easily implemented on standard DSPs. The modulation has been implemented
    to LLC converters where experimental measurement results proved its effectiveness
    for LLC converters by reducing the temperature deviation from 6.3 K to only 0.2
    K such that the peak temperature is reduced from 95 °C to 92 °C. The paper also
    proves that the modulation can be utilized to improve the efficiency of LLC converters
    operated at very low gains while simultaneously reducing the junction temperature
    of all four switches compared to the conventional complementary modulation. Finally,
    EMI implications are analyzed, which show that the modulation may be beneficial
    for reducing the common-mode emissions around the operating frequency.
author:
- first_name: Philipp
  full_name: Rehlaender, Philipp
  id: '69469'
  last_name: Rehlaender
- first_name: Roland
  full_name: Unruh, Roland
  id: '34289'
  last_name: Unruh
- first_name: Frank
  full_name: Schafmeister, Frank
  id: '71291'
  last_name: Schafmeister
- first_name: Joachim
  full_name: Böcker, Joachim
  id: '66'
  last_name: Böcker
  orcid: 0000-0002-8480-7295
citation:
  ama: 'Rehlaender P, Unruh R, Schafmeister F, Böcker J. Alternating Asymmetrical
    Phase-Shift Modulation for Full-Bridge Converters with Balanced Switching Losses
    to Reduce Thermal Imbalances. In: <i>2021 IEEE Applied Power Electronics Conference
    and Exposition (APEC)</i>. IEEE; 2021. doi:<a href="https://doi.org/10.1109/apec42165.2021.9487104">10.1109/apec42165.2021.9487104</a>'
  apa: Rehlaender, P., Unruh, R., Schafmeister, F., &#38; Böcker, J. (2021). Alternating
    Asymmetrical Phase-Shift Modulation for Full-Bridge Converters with Balanced Switching
    Losses to Reduce Thermal Imbalances. <i>2021 IEEE Applied Power Electronics Conference
    and Exposition (APEC)</i>. 2021 IEEE Applied Power Electronics Conference and
    Exposition (APEC), Phoenix, AZ, USA. <a href="https://doi.org/10.1109/apec42165.2021.9487104">https://doi.org/10.1109/apec42165.2021.9487104</a>
  bibtex: '@inproceedings{Rehlaender_Unruh_Schafmeister_Böcker_2021, title={Alternating
    Asymmetrical Phase-Shift Modulation for Full-Bridge Converters with Balanced Switching
    Losses to Reduce Thermal Imbalances}, DOI={<a href="https://doi.org/10.1109/apec42165.2021.9487104">10.1109/apec42165.2021.9487104</a>},
    booktitle={2021 IEEE Applied Power Electronics Conference and Exposition (APEC)},
    publisher={IEEE}, author={Rehlaender, Philipp and Unruh, Roland and Schafmeister,
    Frank and Böcker, Joachim}, year={2021} }'
  chicago: Rehlaender, Philipp, Roland Unruh, Frank Schafmeister, and Joachim Böcker.
    “Alternating Asymmetrical Phase-Shift Modulation for Full-Bridge Converters with
    Balanced Switching Losses to Reduce Thermal Imbalances.” In <i>2021 IEEE Applied
    Power Electronics Conference and Exposition (APEC)</i>. IEEE, 2021. <a href="https://doi.org/10.1109/apec42165.2021.9487104">https://doi.org/10.1109/apec42165.2021.9487104</a>.
  ieee: 'P. Rehlaender, R. Unruh, F. Schafmeister, and J. Böcker, “Alternating Asymmetrical
    Phase-Shift Modulation for Full-Bridge Converters with Balanced Switching Losses
    to Reduce Thermal Imbalances,” presented at the 2021 IEEE Applied Power Electronics
    Conference and Exposition (APEC), Phoenix, AZ, USA, 2021, doi: <a href="https://doi.org/10.1109/apec42165.2021.9487104">10.1109/apec42165.2021.9487104</a>.'
  mla: Rehlaender, Philipp, et al. “Alternating Asymmetrical Phase-Shift Modulation
    for Full-Bridge Converters with Balanced Switching Losses to Reduce Thermal Imbalances.”
    <i>2021 IEEE Applied Power Electronics Conference and Exposition (APEC)</i>, IEEE,
    2021, doi:<a href="https://doi.org/10.1109/apec42165.2021.9487104">10.1109/apec42165.2021.9487104</a>.
  short: 'P. Rehlaender, R. Unruh, F. Schafmeister, J. Böcker, in: 2021 IEEE Applied
    Power Electronics Conference and Exposition (APEC), IEEE, 2021.'
conference:
  end_date: 2021-06-17
  location: Phoenix, AZ, USA
  name: 2021 IEEE Applied Power Electronics Conference and Exposition (APEC)
  start_date: 2021-06-14
date_created: 2022-02-20T21:19:46Z
date_updated: 2023-10-20T11:50:25Z
department:
- _id: '34'
- _id: '52'
doi: 10.1109/apec42165.2021.9487104
keyword:
- Phase-Shifted Full Bridge
- Full-Bridge Converter
- Phase-Shift Control
- Phase-Shift Modulation
- LLC Converter
- Thermal Balancing
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/9487104
publication: 2021 IEEE Applied Power Electronics Conference and Exposition (APEC)
publication_identifier:
  isbn:
  - 978-1-7281-8950-5
publication_status: published
publisher: IEEE
status: public
title: Alternating Asymmetrical Phase-Shift Modulation for Full-Bridge Converters
  with Balanced Switching Losses to Reduce Thermal Imbalances
type: conference
user_id: '34289'
year: '2021'
...