---
_id: '34176'
abstract:
- lang: eng
text: Cascaded H-bridge Converters (CHBs) are a promising solution in converting
power from a three-phase medium voltage of 6.6 kV...30 kV to a lower DC-voltage
in the range of 100 V...1 kV to provide pure DC power to applications such as
electrolyzers for hydrogen generation, data centers with a DC power distribution
and DC microgrids. CHBs can be interpreted as modular multilevel converters with
an isolated DC-DC output stage per module, require a large DC-link capacitor for
each module to handle the second harmonic voltage ripple caused by the fluctuating
input power within a fundamental grid period. Without a zero-sequence voltage
injection, star-connected CHBs are operated with approximately sinusoidal arm
voltages and currents. The floating star point potential enables to utilize different
zero-sequence voltage injection techniques such as a third-harmonic injection
with 1/6 of the grid voltage amplitude or a Min-Max voltage injection. Both well-known
methods have the advantage to reduce the peak arm voltage and thereby the number
of required modules by 13.4 % (to √ 3 2). This paper proves analytically that
the third-harmonic injection with 1/6 of the grid voltage amplitude reduces the
second harmonic voltage ripple by only 15.1 % compared to no-voltage injection
for unity power factor operation and balanced grid voltages. Then it is shown,
that the Min-Max injection has the often overlooked advantage of reducing the
second harmonic voltage ripple by even 18.8 %. By applying the here proposed zero-sequence
voltage injection in saturation modulation, the second harmonic voltage ripple
of the DC-link capacitors is reduced by even 24.3 %, while still requiring the
same number of modules as the Min-Max injection. For a realistic number of reserve
modules, the overall energy ripple in the DC-link capacitors is reduced by 40
%.
author:
- 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: 'Unruh R, Schafmeister F, Böcker J. Zero-Sequence Voltage Reduces DC-Link Capacitor
Demand in Cascaded H-Bridge Converters for Large-Scale Electrolyzers by 40%. In:
24th European Conference on Power Electronics and Applications (EPE’22 ECCE
Europe). IEEE; 2022.'
apa: Unruh, R., Schafmeister, F., & Böcker, J. (2022). Zero-Sequence Voltage
Reduces DC-Link Capacitor Demand in Cascaded H-Bridge Converters for Large-Scale
Electrolyzers by 40%. 24th European Conference on Power Electronics and Applications
(EPE’22 ECCE Europe). 24th European Conference on Power Electronics and Applications
(EPE’22 ECCE Europe), Hanover, Germany.
bibtex: '@inproceedings{Unruh_Schafmeister_Böcker_2022, title={Zero-Sequence Voltage
Reduces DC-Link Capacitor Demand in Cascaded H-Bridge Converters for Large-Scale
Electrolyzers by 40%}, booktitle={24th European Conference on Power Electronics
and Applications (EPE’22 ECCE Europe)}, publisher={IEEE}, author={Unruh, Roland
and Schafmeister, Frank and Böcker, Joachim}, year={2022} }'
chicago: Unruh, Roland, Frank Schafmeister, and Joachim Böcker. “Zero-Sequence Voltage
Reduces DC-Link Capacitor Demand in Cascaded H-Bridge Converters for Large-Scale
Electrolyzers by 40%.” In 24th European Conference on Power Electronics and
Applications (EPE’22 ECCE Europe). IEEE, 2022.
ieee: R. Unruh, F. Schafmeister, and J. Böcker, “Zero-Sequence Voltage Reduces DC-Link
Capacitor Demand in Cascaded H-Bridge Converters for Large-Scale Electrolyzers
by 40%,” presented at the 24th European Conference on Power Electronics and Applications
(EPE’22 ECCE Europe), Hanover, Germany, 2022.
mla: Unruh, Roland, et al. “Zero-Sequence Voltage Reduces DC-Link Capacitor Demand
in Cascaded H-Bridge Converters for Large-Scale Electrolyzers by 40%.” 24th
European Conference on Power Electronics and Applications (EPE’22 ECCE Europe),
IEEE, 2022.
short: 'R. Unruh, F. Schafmeister, J. Böcker, in: 24th European Conference on Power
Electronics and Applications (EPE’22 ECCE Europe), IEEE, 2022.'
conference:
end_date: 2022-09-09
location: Hanover, Germany
name: 24th European Conference on Power Electronics and Applications (EPE'22 ECCE
Europe)
start_date: 2022-09-05
date_created: 2022-12-02T12:47:38Z
date_updated: 2023-10-23T09:04:23Z
department:
- _id: '52'
keyword:
- Cascaded H-Bridge
- Solid-State Transformer
- Zero sequence voltage
- Third harmonic injection
- Capacitor voltage ripple
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/9907278
publication: 24th European Conference on Power Electronics and Applications (EPE'22
ECCE Europe)
publication_identifier:
isbn:
- 978-9-0758-1539-9
publication_status: published
publisher: IEEE
status: public
title: Zero-Sequence Voltage Reduces DC-Link Capacitor Demand in Cascaded H-Bridge
Converters for Large-Scale Electrolyzers by 40%
type: conference
user_id: '34289'
year: '2022'
...
---
_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: '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: 2021 IEEE Applied Power Electronics Conference
and Exposition (APEC). IEEE; 2021. doi:10.1109/apec42165.2021.9487104'
apa: Rehlaender, P., Unruh, R., Schafmeister, F., & Böcker, J. (2021). Alternating
Asymmetrical Phase-Shift Modulation for Full-Bridge Converters with Balanced Switching
Losses to Reduce Thermal Imbalances. 2021 IEEE Applied Power Electronics Conference
and Exposition (APEC). 2021 IEEE Applied Power Electronics Conference and
Exposition (APEC), Phoenix, AZ, USA. https://doi.org/10.1109/apec42165.2021.9487104
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={10.1109/apec42165.2021.9487104},
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 2021 IEEE Applied
Power Electronics Conference and Exposition (APEC). IEEE, 2021. https://doi.org/10.1109/apec42165.2021.9487104.
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: 10.1109/apec42165.2021.9487104.'
mla: Rehlaender, Philipp, et al. “Alternating Asymmetrical Phase-Shift Modulation
for Full-Bridge Converters with Balanced Switching Losses to Reduce Thermal Imbalances.”
2021 IEEE Applied Power Electronics Conference and Exposition (APEC), IEEE,
2021, doi:10.1109/apec42165.2021.9487104.
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'
...
---
_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'
...
---
_id: '29939'
abstract:
- lang: eng
text: In this paper, a full-bridge modular multilevel converter (MMC) and two half-bridge-based
MMCs are evaluated for high-current low-voltage e.g. 100 - 400V DC-applications
such as electrolysis, arc welding or datacenters with DC-power distribution. Usually,
modular multilevel converters are used in high-voltage DC-applications (HVDC)
in the multiple kV-range, but to meet the needs of a high-current demand at low
output voltage levels, the modular converter concept requires adaptations. In
the proposed concept, the MMC is used to step-down the three-phase medium-voltage
of 10kV, and provide up to 1 MW to the load. Therefore, each module is extended
by an LLC resonant converter to adapt to the specific electrolyzers DC-voltage
range of 142 - 220V and to provide galvanic isolation. The six-arm MMC converter
with half-bridge modules can be simplified and optimized by removing three arms,
and thus halving the number of modules. In addition, the module voltage ripple
and capacitor losses are decreased by 22% and 30% respectively. By rearranging
the components of the half-bridge MMC to build a MMC consisting of grid-side full-bridge
modules, the voltage ripple is further reduced by 78% and capacitor losses by
64%, while ensuring identical costs and volume for all MMCs. Finally, the LLC
resonant converter is designed for the most efficient full-bridge MMC. The LLC
can not operate at resonance with a fixed nominal module voltage of 770V because
the output voltage is varying between 142 - 220V. By decreasing the module voltage
down to 600V, additional points of operation can be operated in resonance, and
the remaining are closer to resonance. The option to decrease the module voltage
down to 600V, increases the number of required modules per arm from 12 to 15,
which requires to balance the losses of the LLCs and the grid-side stages.
author:
- 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: 'Unruh R, Schafmeister F, Böcker J. Evaluation of MMCs for High-Power Low-Voltage
DC-Applications in Combination with the Module LLC-Design. In: 2020 22nd European
Conference on Power Electronics and Applications (EPE’20 ECCE Europe). IEEE;
2020. doi:10.23919/epe20ecceeurope43536.2020.9215687'
apa: Unruh, R., Schafmeister, F., & Böcker, J. (2020). Evaluation of MMCs for
High-Power Low-Voltage DC-Applications in Combination with the Module LLC-Design.
2020 22nd European Conference on Power Electronics and Applications (EPE’20
ECCE Europe). 22nd European Conference on Power Electronics and Applications
(EPE’20 ECCE Europe), Lyon, France. https://doi.org/10.23919/epe20ecceeurope43536.2020.9215687
bibtex: '@inproceedings{Unruh_Schafmeister_Böcker_2020, title={Evaluation of MMCs
for High-Power Low-Voltage DC-Applications in Combination with the Module LLC-Design},
DOI={10.23919/epe20ecceeurope43536.2020.9215687},
booktitle={2020 22nd European Conference on Power Electronics and Applications
(EPE’20 ECCE Europe)}, publisher={IEEE}, author={Unruh, Roland and Schafmeister,
Frank and Böcker, Joachim}, year={2020} }'
chicago: Unruh, Roland, Frank Schafmeister, and Joachim Böcker. “Evaluation of MMCs
for High-Power Low-Voltage DC-Applications in Combination with the Module LLC-Design.”
In 2020 22nd European Conference on Power Electronics and Applications (EPE’20
ECCE Europe). IEEE, 2020. https://doi.org/10.23919/epe20ecceeurope43536.2020.9215687.
ieee: 'R. Unruh, F. Schafmeister, and J. Böcker, “Evaluation of MMCs for High-Power
Low-Voltage DC-Applications in Combination with the Module LLC-Design,” presented
at the 22nd European Conference on Power Electronics and Applications (EPE’20
ECCE Europe), Lyon, France, 2020, doi: 10.23919/epe20ecceeurope43536.2020.9215687.'
mla: Unruh, Roland, et al. “Evaluation of MMCs for High-Power Low-Voltage DC-Applications
in Combination with the Module LLC-Design.” 2020 22nd European Conference on
Power Electronics and Applications (EPE’20 ECCE Europe), IEEE, 2020, doi:10.23919/epe20ecceeurope43536.2020.9215687.
short: 'R. Unruh, F. Schafmeister, J. Böcker, in: 2020 22nd European Conference
on Power Electronics and Applications (EPE’20 ECCE Europe), IEEE, 2020.'
conference:
end_date: 2020-09-11
location: Lyon, France
name: 22nd European Conference on Power Electronics and Applications (EPE'20 ECCE
Europe)
start_date: 2020-09-07
date_created: 2022-02-21T16:33:14Z
date_updated: 2022-02-21T17:00:16Z
department:
- _id: '52'
doi: 10.23919/epe20ecceeurope43536.2020.9215687
keyword:
- Multilevel converters
- Resonant converter
- High voltage power converters
- ZVS Converters
- Combination MMC LLC
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/9215687
publication: 2020 22nd European Conference on Power Electronics and Applications (EPE'20
ECCE Europe)
publication_status: published
publisher: IEEE
status: public
title: Evaluation of MMCs for High-Power Low-Voltage DC-Applications in Combination
with the Module LLC-Design
type: conference
user_id: '34289'
year: '2020'
...
---
_id: '29940'
abstract:
- lang: eng
text: A full-bridge modular multilevel converter (MMC) is compared to a half-bridge-based
MMC for high-current low-voltage DC-applications such as electrolysis, arc welding
or datacenters with DC-power distribution. Usually, modular multilevel converters
are used in high-voltage DC-applications (HVDC) in the multiple kV-range, but
to meet the needs of a high-current demand at low output voltage levels, the modular
converter concept requires adaptations. In the proposed concept, the MMC is used
to step-down the three-phase medium-voltage of 10 kV. Therefore, each module is
extended by an LLC resonant converter to adapt to the specific electrolyzers DC-voltage
range of 142-220V and to provide galvanic isolation. The proposed MMC converter
with full-bridge modules uses half the number of modules compared to a half-bridge-based
MMC while reducing the voltage ripple by 78% and capacitor losses by 64% by rearranging
the same components to ensure identical costs and volume. For additional reliability,
a new robust algorithm for balancing conduction losses during the bypass phase
is presented.
author:
- 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: Norbert
full_name: Fröhleke, Norbert
last_name: Fröhleke
- first_name: Joachim
full_name: Böcker, Joachim
id: '66'
last_name: Böcker
orcid: 0000-0002-8480-7295
citation:
ama: 'Unruh R, Schafmeister F, Fröhleke N, Böcker J. 1-MW Full-Bridge MMC for High-Current
Low-Voltage (100V-400V) DC-Applications. In: PCIM Europe Digital Days 2020;
International Exhibition and Conference for Power Electronics, Intelligent Motion,
Renewable Energy and Energy Management. VDE; 2020.'
apa: Unruh, R., Schafmeister, F., Fröhleke, N., & Böcker, J. (2020). 1-MW Full-Bridge
MMC for High-Current Low-Voltage (100V-400V) DC-Applications. PCIM Europe Digital
Days 2020; International Exhibition and Conference for Power Electronics, Intelligent
Motion, Renewable Energy and Energy Management. PCIM Europe digital days 2020,
Germany.
bibtex: '@inproceedings{Unruh_Schafmeister_Fröhleke_Böcker_2020, title={1-MW Full-Bridge
MMC for High-Current Low-Voltage (100V-400V) DC-Applications}, booktitle={PCIM
Europe digital days 2020; International Exhibition and Conference for Power Electronics,
Intelligent Motion, Renewable Energy and Energy Management}, publisher={VDE},
author={Unruh, Roland and Schafmeister, Frank and Fröhleke, Norbert and Böcker,
Joachim}, year={2020} }'
chicago: Unruh, Roland, Frank Schafmeister, Norbert Fröhleke, and Joachim Böcker.
“1-MW Full-Bridge MMC for High-Current Low-Voltage (100V-400V) DC-Applications.”
In PCIM Europe Digital Days 2020; International Exhibition and Conference for
Power Electronics, Intelligent Motion, Renewable Energy and Energy Management.
VDE, 2020.
ieee: R. Unruh, F. Schafmeister, N. Fröhleke, and J. Böcker, “1-MW Full-Bridge MMC
for High-Current Low-Voltage (100V-400V) DC-Applications,” presented at the PCIM
Europe digital days 2020, Germany, 2020.
mla: Unruh, Roland, et al. “1-MW Full-Bridge MMC for High-Current Low-Voltage (100V-400V)
DC-Applications.” PCIM Europe Digital Days 2020; International Exhibition and
Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy
Management, VDE, 2020.
short: 'R. Unruh, F. Schafmeister, N. Fröhleke, J. Böcker, in: PCIM Europe Digital
Days 2020; International Exhibition and Conference for Power Electronics, Intelligent
Motion, Renewable Energy and Energy Management, VDE, 2020.'
conference:
end_date: 2020-07-08
location: Germany
name: PCIM Europe digital days 2020
start_date: 2020-07-07
date_created: 2022-02-21T16:42:30Z
date_updated: 2023-10-20T11:52:39Z
department:
- _id: '52'
keyword:
- Cascaded H-Bridge
- Solid-State Transformer
- Capacitor voltage ripple
- Zero sequence voltage
- Full-Bridge
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/9178138
publication: PCIM Europe digital days 2020; International Exhibition and Conference
for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management
publication_identifier:
isbn:
- 978-3-8007-5245-4
publication_status: published
publisher: VDE
status: public
title: 1-MW Full-Bridge MMC for High-Current Low-Voltage (100V-400V) DC-Applications
type: conference
user_id: '34289'
year: '2020'
...
---
_id: '29880'
abstract:
- lang: eng
text: Although there are numerous design methodologies for the LLC resonant converter,
they often do not consider the possibility of input voltage adjustment. In the
proposed concept, a modular multi-level converter (MMC) is used to step-down the
three-phase medium voltage of 10 kV, and provide up to 1 MW of pure DC power to
the load consisting of electrolyzers for hydrogen generation. Therefore, each
module is extended by an LLC resonant converter to adapt to the specific electrolyzers
DC voltage range of 142...220 V and to provide galvanic isolation. In order to
achieve a high efficiency for a wide range of load conditions, the input voltage
of the LLC converter is adjusted between 600 V and 770 V while operating at resonance
or close to resonance. The parameters of the 11kW LLC resonant converter with
an integrated leakage inductance are systematically optimized to maximize the
efficiency for all loads while achieving zero-voltage switching. For a fast estimation
of eddy current losses, a new method is proposed, which uses a single FEM simulation
to fit newly developed loss equations. The calculated average efficiency is 97.8%.
The prototype of the LLC converter reaches a peak efficiency of over 98% at resonance
at half load which is similar to the precalculated value.
author:
- 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: 'Unruh R, Schafmeister F, Böcker J. 11kW, 70kHz LLC Converter Design with Adaptive
Input Voltage for 98% Efficiency in an MMC. In: 2020 IEEE 21st Workshop on
Control and Modeling for Power Electronics (COMPEL). IEEE; 2020. doi:10.1109/compel49091.2020.9265771'
apa: Unruh, R., Schafmeister, F., & Böcker, J. (2020). 11kW, 70kHz LLC Converter
Design with Adaptive Input Voltage for 98% Efficiency in an MMC. 2020 IEEE
21st Workshop on Control and Modeling for Power Electronics (COMPEL). https://doi.org/10.1109/compel49091.2020.9265771
bibtex: '@inproceedings{Unruh_Schafmeister_Böcker_2020, title={11kW, 70kHz LLC Converter
Design with Adaptive Input Voltage for 98% Efficiency in an MMC}, DOI={10.1109/compel49091.2020.9265771},
booktitle={2020 IEEE 21st Workshop on Control and Modeling for Power Electronics
(COMPEL)}, publisher={IEEE}, author={Unruh, Roland and Schafmeister, Frank and
Böcker, Joachim}, year={2020} }'
chicago: Unruh, Roland, Frank Schafmeister, and Joachim Böcker. “11kW, 70kHz LLC
Converter Design with Adaptive Input Voltage for 98% Efficiency in an MMC.” In
2020 IEEE 21st Workshop on Control and Modeling for Power Electronics (COMPEL).
IEEE, 2020. https://doi.org/10.1109/compel49091.2020.9265771.
ieee: 'R. Unruh, F. Schafmeister, and J. Böcker, “11kW, 70kHz LLC Converter Design
with Adaptive Input Voltage for 98% Efficiency in an MMC,” 2020, doi: 10.1109/compel49091.2020.9265771.'
mla: Unruh, Roland, et al. “11kW, 70kHz LLC Converter Design with Adaptive Input
Voltage for 98% Efficiency in an MMC.” 2020 IEEE 21st Workshop on Control and
Modeling for Power Electronics (COMPEL), IEEE, 2020, doi:10.1109/compel49091.2020.9265771.
short: 'R. Unruh, F. Schafmeister, J. Böcker, in: 2020 IEEE 21st Workshop on Control
and Modeling for Power Electronics (COMPEL), IEEE, 2020.'
conference:
end_date: 2020-11-12
start_date: 2020-11-09
date_created: 2022-02-18T16:29:08Z
date_updated: 2024-11-28T14:19:07Z
department:
- _id: '52'
doi: 10.1109/compel49091.2020.9265771
keyword:
- Full-bridge
- High voltage power converters
- LLC resonant converter
- Multilevel converters
- ZVS Converters
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/9265771
publication: 2020 IEEE 21st Workshop on Control and Modeling for Power Electronics
(COMPEL)
publication_identifier:
unknown:
- 978-1-7281-7160-9
publication_status: published
publisher: IEEE
quality_controlled: '1'
status: public
title: 11kW, 70kHz LLC Converter Design with Adaptive Input Voltage for 98% Efficiency
in an MMC
type: conference
user_id: '34289'
year: '2020'
...
---
_id: '29942'
abstract:
- lang: eng
text: Due to recent developments in MMCs, they are used in many medium-voltage and
high-power applications today, but efficient and modular solutions for high-power
at low-voltage such as for electrolysis are still required. The proposed Y-MMC
converts the grid AC-voltage into a DC-voltages, and an LLC converter is connected
to each submodule capacitor to provide the required current to the DC-load. This
paper proposes a topology that uses only half the number of submodules and moreover
to reduce the effective switching frequency by a third, while preserving the same
THD und output power of an YY-MMC.
author:
- 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: Norbert
full_name: Fröhleke, Norbert
last_name: Fröhleke
- first_name: Joachim
full_name: Böcker, Joachim
id: '66'
last_name: Böcker
orcid: 0000-0002-8480-7295
citation:
ama: 'Unruh R, Schafmeister F, Fröhleke N, Böcker J. MMC-Topology for High-Current
and Low-Voltage Applications with Minimal Number of Submodules, Reduced Switching
and Capacitor Losses. In: PCIM Europe 2019; International Exhibition and Conference
for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management.
VDE; 2019.'
apa: Unruh, R., Schafmeister, F., Fröhleke, N., & Böcker, J. (2019). MMC-Topology
for High-Current and Low-Voltage Applications with Minimal Number of Submodules,
Reduced Switching and Capacitor Losses. PCIM Europe 2019; International Exhibition
and Conference for Power Electronics, Intelligent Motion, Renewable Energy and
Energy Management. PCIM Europe 2019, Nuremberg, Germany.
bibtex: '@inproceedings{Unruh_Schafmeister_Fröhleke_Böcker_2019, title={MMC-Topology
for High-Current and Low-Voltage Applications with Minimal Number of Submodules,
Reduced Switching and Capacitor Losses}, booktitle={PCIM Europe 2019; International
Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable
Energy and Energy Management}, publisher={VDE}, author={Unruh, Roland and Schafmeister,
Frank and Fröhleke, Norbert and Böcker, Joachim}, year={2019} }'
chicago: Unruh, Roland, Frank Schafmeister, Norbert Fröhleke, and Joachim Böcker.
“MMC-Topology for High-Current and Low-Voltage Applications with Minimal Number
of Submodules, Reduced Switching and Capacitor Losses.” In PCIM Europe 2019;
International Exhibition and Conference for Power Electronics, Intelligent Motion,
Renewable Energy and Energy Management. VDE, 2019.
ieee: R. Unruh, F. Schafmeister, N. Fröhleke, and J. Böcker, “MMC-Topology for High-Current
and Low-Voltage Applications with Minimal Number of Submodules, Reduced Switching
and Capacitor Losses,” presented at the PCIM Europe 2019, Nuremberg, Germany,
2019.
mla: Unruh, Roland, et al. “MMC-Topology for High-Current and Low-Voltage Applications
with Minimal Number of Submodules, Reduced Switching and Capacitor Losses.” PCIM
Europe 2019; International Exhibition and Conference for Power Electronics, Intelligent
Motion, Renewable Energy and Energy Management, VDE, 2019.
short: 'R. Unruh, F. Schafmeister, N. Fröhleke, J. Böcker, in: PCIM Europe 2019;
International Exhibition and Conference for Power Electronics, Intelligent Motion,
Renewable Energy and Energy Management, VDE, 2019.'
conference:
end_date: 2019-05-09
location: Nuremberg, Germany
name: PCIM Europe 2019
start_date: 2019-05-07
date_created: 2022-02-21T16:57:29Z
date_updated: 2022-02-23T15:49:43Z
department:
- _id: '52'
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/document/8767739
publication: PCIM Europe 2019; International Exhibition and Conference for Power Electronics,
Intelligent Motion, Renewable Energy and Energy Management
publication_identifier:
isbn:
- 978-3-8007-4938-6
publication_status: published
publisher: VDE
status: public
title: MMC-Topology for High-Current and Low-Voltage Applications with Minimal Number
of Submodules, Reduced Switching and Capacitor Losses
type: conference
user_id: '66'
year: '2019'
...