---
_id: '29938'
abstract:
- lang: eng
text: Modular solid-state transformers (SSTs) are a promising technology in converting
power from a 10kV three-phase medium voltage to a lower DC-voltage in the range
of 100…400V to provide pure DC power to applications such as electrolyzers for
hydrogen generation, data centers with a DC power distribution and DC micro grids.
Modular SSTs which can be interpreted as modular multilevel converters with an
isolated DC-DC output stage per module, are designed with redundant modules to
increase reliability. Usually, each of the three arms operates independently,
and therefore, only a fixed number of faulty modules can be compensated in each
arm, even if all modules are operational in the remaining two arms. With the proposed
zero-sequence voltage injection, up to 100% more faulty modules can be compensated
in an arm by employing the same hardware. In addition, module power imbalances
are nearly eliminated by utilizing a fundamental frequency zero-sequence voltage.
A dominant 3rd harmonic zero-sequence voltage injection in combination with the
5th, 7th and several higher order harmonics with adaptive (small) amplitudes minimize
the required arm voltages at steady-state. For nominal operation or symmetrical
faults, the proposed technique is equivalent to the well known Min-Max voltage
injection, which already reduces the peak arm voltage by 13.4% compared to a constant
star point potential. A statistical analysis proves, that the expected number
of tolerable faulty modules of the 1MW SST increases by 12% without the need for
additional hardware.
author:
- first_name: Roland
full_name: Unruh, Roland
id: '34289'
last_name: Unruh
- first_name: Jarren
full_name: Lange, Jarren
id: '78801'
last_name: Lange
- 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: 'Unruh R, Lange J, Schafmeister F, Böcker J. Adaptive Zero-Sequence Voltage
Injection for Modular Solid-State Transformer to Compensate for Asymmetrical Fault
Conditions. In: 23rd European Conference on Power Electronics and Applications
(EPE’21 ECCE Europe). IEEE; 2021. doi:https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542'
apa: Unruh, R., Lange, J., Schafmeister, F., & Böcker, J. (2021). Adaptive Zero-Sequence
Voltage Injection for Modular Solid-State Transformer to Compensate for Asymmetrical
Fault Conditions. 23rd European Conference on Power Electronics and Applications
(EPE’21 ECCE Europe). 23rd European Conference on Power Electronics and Applications
(EPE’21 ECCE Europe), Ghent, Belgium. https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542
bibtex: '@inproceedings{Unruh_Lange_Schafmeister_Böcker_2021, title={Adaptive Zero-Sequence
Voltage Injection for Modular Solid-State Transformer to Compensate for Asymmetrical
Fault Conditions}, DOI={https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542},
booktitle={23rd European Conference on Power Electronics and Applications (EPE’21
ECCE Europe)}, publisher={IEEE}, author={Unruh, Roland and Lange, Jarren and Schafmeister,
Frank and Böcker, Joachim}, year={2021} }'
chicago: Unruh, Roland, Jarren Lange, Frank Schafmeister, and Joachim Böcker. “Adaptive
Zero-Sequence Voltage Injection for Modular Solid-State Transformer to Compensate
for Asymmetrical Fault Conditions.” In 23rd European Conference on Power Electronics
and Applications (EPE’21 ECCE Europe). IEEE, 2021. https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542.
ieee: 'R. Unruh, J. Lange, F. Schafmeister, and J. Böcker, “Adaptive Zero-Sequence
Voltage Injection for Modular Solid-State Transformer to Compensate for Asymmetrical
Fault Conditions,” presented at the 23rd European Conference on Power Electronics
and Applications (EPE’21 ECCE Europe), Ghent, Belgium, 2021, doi: https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542.'
mla: Unruh, Roland, et al. “Adaptive Zero-Sequence Voltage Injection for Modular
Solid-State Transformer to Compensate for Asymmetrical Fault Conditions.” 23rd
European Conference on Power Electronics and Applications (EPE’21 ECCE Europe),
IEEE, 2021, doi:https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542.
short: 'R. Unruh, J. Lange, F. Schafmeister, J. Böcker, in: 23rd European Conference
on Power Electronics and Applications (EPE’21 ECCE Europe), IEEE, 2021.'
conference:
end_date: 2021-09-10
location: Ghent, Belgium
name: 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE
Europe)
start_date: 2021-09-06
date_created: 2022-02-21T16:31:34Z
date_updated: 2022-09-09T12:01:42Z
department:
- _id: '52'
doi: https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542
keyword:
- Solid-State Transformer
- Zero sequence voltage
- Fault handling strategy
- Power balance control technique
- Three-phase system
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/9570542
publication: 23rd European Conference on Power Electronics and Applications (EPE'21
ECCE Europe)
publication_identifier:
isbn:
- 978-9-0758-1537-5
publication_status: published
publisher: IEEE
status: public
title: Adaptive Zero-Sequence Voltage Injection for Modular Solid-State Transformer
to Compensate for Asymmetrical Fault Conditions
type: conference
user_id: '34289'
year: '2021'
...
---
_id: '29899'
abstract:
- lang: eng
text: LLC resonant converters are typically unsuitable to be applied for wide voltage-transfer
ratio applications. With a full-bridge inverter, however, they can be operated
in a variety of different modulations. Most notably, by permanently turning on
one MOSFET and turning off the other MOSFET of the same bridge leg, the LLC can
be operated in half-bridge configuration reducing the gain by a factor of two.
The resonant capacitor is hereby charged to an average voltage of half the input
voltage. In this modulation, however, the switch that is permanently turned on
is stressed by the complete resonant current while exhibiting no switching losses.
This paper proves that the frequency-doubler modulation can better balance the
losses among all MOSFETs and should be the preferred mode of operation favored
over the conventional half-bridge modulation. This paper analyzes the beneficial
loss distribution, proposes an on-the-fly morphing modulation and discusses potential
operating strategies to further reduce the junction temperature. Furthermore,
it is shown that this modulation can also be altered to achieve the asymmetrical
LLC operation. Experimental measurement results show that the modulation results
in a substantial decrease of the maximum MOSFET temperature and shows that the
converter can be smoothly transitioned during operation from full-bridge modulation
to the frequency-doubler half-bridge operation and back.
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: Lars
full_name: Hankeln, Lars
last_name: Hankeln
- 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, Hankeln L, Schafmeister F, Böcker J. Frequency-Doubler
Modulation for Reduced Junction Temperatures for LLC Resonant Converters Operated
in Half-Bridge Configuration. In: 23rd European Conference on Power Electronics
and Applications (EPE’21 ECCE Europe). IEEE; 2021. doi:10.23919/EPE21ECCEEurope50061.2021.9570674'
apa: Rehlaender, P., Unruh, R., Hankeln, L., Schafmeister, F., & Böcker, J.
(2021). Frequency-Doubler Modulation for Reduced Junction Temperatures for LLC
Resonant Converters Operated in Half-Bridge Configuration. 23rd European Conference
on Power Electronics and Applications (EPE’21 ECCE Europe). 23rd European
Conference on Power Electronics and Applications (EPE’21 ECCE Europe), Ghent,
Belgium. https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570674
bibtex: '@inproceedings{Rehlaender_Unruh_Hankeln_Schafmeister_Böcker_2021, title={Frequency-Doubler
Modulation for Reduced Junction Temperatures for LLC Resonant Converters Operated
in Half-Bridge Configuration}, DOI={10.23919/EPE21ECCEEurope50061.2021.9570674},
booktitle={23rd European Conference on Power Electronics and Applications (EPE’21
ECCE Europe)}, publisher={IEEE}, author={Rehlaender, Philipp and Unruh, Roland
and Hankeln, Lars and Schafmeister, Frank and Böcker, Joachim}, year={2021} }'
chicago: Rehlaender, Philipp, Roland Unruh, Lars Hankeln, Frank Schafmeister, and
Joachim Böcker. “Frequency-Doubler Modulation for Reduced Junction Temperatures
for LLC Resonant Converters Operated in Half-Bridge Configuration.” In 23rd
European Conference on Power Electronics and Applications (EPE’21 ECCE Europe).
IEEE, 2021. https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570674.
ieee: 'P. Rehlaender, R. Unruh, L. Hankeln, F. Schafmeister, and J. Böcker, “Frequency-Doubler
Modulation for Reduced Junction Temperatures for LLC Resonant Converters Operated
in Half-Bridge Configuration,” presented at the 23rd European Conference on Power
Electronics and Applications (EPE’21 ECCE Europe), Ghent, Belgium, 2021, doi:
10.23919/EPE21ECCEEurope50061.2021.9570674.'
mla: Rehlaender, Philipp, et al. “Frequency-Doubler Modulation for Reduced Junction
Temperatures for LLC Resonant Converters Operated in Half-Bridge Configuration.”
23rd European Conference on Power Electronics and Applications (EPE’21 ECCE
Europe), IEEE, 2021, doi:10.23919/EPE21ECCEEurope50061.2021.9570674.
short: 'P. Rehlaender, R. Unruh, L. Hankeln, F. Schafmeister, J. Böcker, in: 23rd
European Conference on Power Electronics and Applications (EPE’21 ECCE Europe),
IEEE, 2021.'
conference:
end_date: 2021-09-10
location: Ghent, Belgium
name: 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE
Europe)
start_date: 2021-09-06
date_created: 2022-02-20T21:29:48Z
date_updated: 2023-02-09T11:01:11Z
department:
- _id: '34'
- _id: '52'
doi: 10.23919/EPE21ECCEEurope50061.2021.9570674
keyword:
- Resonant converter
- High frequency power converter
- Switched-mode power supply
- Converter control
- Control methods for electrical systems
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/9570674
publication: 23rd European Conference on Power Electronics and Applications (EPE'21
ECCE Europe)
publication_identifier:
isbn:
- 978-9-0758-1537-5
publication_status: published
publisher: IEEE
status: public
title: Frequency-Doubler Modulation for Reduced Junction Temperatures for LLC Resonant
Converters Operated in Half-Bridge Configuration
type: conference
user_id: '34289'
year: '2021'
...