---
_id: '59805'
abstract:
- lang: eng
text: The LLC converter achieves the highest efficiency in resonant operation. Conventionally,
the input DC-link voltage is controlled to operate the LLC converter at resonance
for the given operating point. However, the DC-link capacitor voltage shows a
low-frequency voltage ripple (typically the second harmonic of grid frequency)
in cascaded converters so that the LLC has to adapt its switching frequency within
the grid period. Conventionally, the LLC converter operates 50% of the time above
the resonant frequency of 40 kHz and 50% below resonance. Both operating conditions
cause additional losses. However, experimental measurements indicate that the
below-resonance operation causes significantly higher losses than above-resonance
operation due to much higher primary and secondary transformer currents. It is
better to increase the DC-link voltage by 30% of the peak-to-peak low-frequency
voltage ripple to mostly avoid below-resonance operation (i.e., from 650 V to
680 V in this case). With the proposed control, the LLC converter operates about
75% of time over resonance and only 25% of time below resonance. The overall efficiency
increases from 97.66% to 97.7% for the average operating point with an 80% load
current. This corresponds to a 2% total loss reduction. Finally, the peak resonance
capacitor voltage decreases from 910 V to 790 V (−13%).
article_number: '1517'
author:
- first_name: Roland
full_name: Unruh, Roland
id: '34289'
last_name: Unruh
- first_name: Joachim
full_name: Böcker, Joachim
id: '66'
last_name: Böcker
orcid: 0000-0002-8480-7295
- first_name: Frank
full_name: Schafmeister, Frank
id: '71291'
last_name: Schafmeister
citation:
ama: Unruh R, Böcker J, Schafmeister F. Adaptive DC-Link Voltage Control for 22
kW, 40 kHz LLC Resonant Converter Considering Low-Frequency Voltage Ripple. Electronics.
2025;14(8). doi:10.3390/electronics14081517
apa: Unruh, R., Böcker, J., & Schafmeister, F. (2025). Adaptive DC-Link Voltage
Control for 22 kW, 40 kHz LLC Resonant Converter Considering Low-Frequency Voltage
Ripple. Electronics, 14(8), Article 1517. https://doi.org/10.3390/electronics14081517
bibtex: '@article{Unruh_Böcker_Schafmeister_2025, title={Adaptive DC-Link Voltage
Control for 22 kW, 40 kHz LLC Resonant Converter Considering Low-Frequency Voltage
Ripple}, volume={14}, DOI={10.3390/electronics14081517},
number={81517}, journal={Electronics}, publisher={MDPI AG}, author={Unruh, Roland
and Böcker, Joachim and Schafmeister, Frank}, year={2025} }'
chicago: Unruh, Roland, Joachim Böcker, and Frank Schafmeister. “Adaptive DC-Link
Voltage Control for 22 KW, 40 KHz LLC Resonant Converter Considering Low-Frequency
Voltage Ripple.” Electronics 14, no. 8 (2025). https://doi.org/10.3390/electronics14081517.
ieee: 'R. Unruh, J. Böcker, and F. Schafmeister, “Adaptive DC-Link Voltage Control
for 22 kW, 40 kHz LLC Resonant Converter Considering Low-Frequency Voltage Ripple,”
Electronics, vol. 14, no. 8, Art. no. 1517, 2025, doi: 10.3390/electronics14081517.'
mla: Unruh, Roland, et al. “Adaptive DC-Link Voltage Control for 22 KW, 40 KHz LLC
Resonant Converter Considering Low-Frequency Voltage Ripple.” Electronics,
vol. 14, no. 8, 1517, MDPI AG, 2025, doi:10.3390/electronics14081517.
short: R. Unruh, J. Böcker, F. Schafmeister, Electronics 14 (2025).
date_created: 2025-05-05T12:27:39Z
date_updated: 2025-05-05T12:34:00Z
department:
- _id: '52'
doi: 10.3390/electronics14081517
intvolume: ' 14'
issue: '8'
keyword:
- adaptive DC-link voltage
- cascaded H-bridge
- resonant operation
- Full-Bridge Converter
- loss minimization
- LLC Resonant Converter
- peak capacitor voltage reduction
language:
- iso: eng
main_file_link:
- url: https://www.mdpi.com/2079-9292/14/8/1517
publication: Electronics
publication_identifier:
issn:
- 2079-9292
publication_status: published
publisher: MDPI AG
status: public
title: Adaptive DC-Link Voltage Control for 22 kW, 40 kHz LLC Resonant Converter Considering
Low-Frequency Voltage Ripple
type: journal_article
user_id: '34289'
volume: 14
year: '2025'
...
---
_id: '63497'
author:
- first_name: Nikolas
full_name: Förster, Nikolas
last_name: Förster
- first_name: Oliver
full_name: Wallscheid, Oliver
last_name: Wallscheid
- first_name: Frank
full_name: Schafmeister, Frank
last_name: Schafmeister
citation:
ama: 'Förster N, Wallscheid O, Schafmeister F. Dual-Active Bridge Sequential Pareto
Optimization for Fast Pre-Design and Final Component Selection. In: 2024 IEEE
Design Methodologies Conference (DMC). ; 2024:1-8. doi:10.1109/DMC62632.2024.10812131'
apa: Förster, N., Wallscheid, O., & Schafmeister, F. (2024). Dual-Active Bridge
Sequential Pareto Optimization for Fast Pre-Design and Final Component Selection.
2024 IEEE Design Methodologies Conference (DMC), 1–8. https://doi.org/10.1109/DMC62632.2024.10812131
bibtex: '@inproceedings{Förster_Wallscheid_Schafmeister_2024, title={Dual-Active
Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component
Selection}, DOI={10.1109/DMC62632.2024.10812131},
booktitle={2024 IEEE Design Methodologies Conference (DMC)}, author={Förster,
Nikolas and Wallscheid, Oliver and Schafmeister, Frank}, year={2024}, pages={1–8}
}'
chicago: Förster, Nikolas, Oliver Wallscheid, and Frank Schafmeister. “Dual-Active
Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component
Selection.” In 2024 IEEE Design Methodologies Conference (DMC), 1–8, 2024.
https://doi.org/10.1109/DMC62632.2024.10812131.
ieee: 'N. Förster, O. Wallscheid, and F. Schafmeister, “Dual-Active Bridge Sequential
Pareto Optimization for Fast Pre-Design and Final Component Selection,” in 2024
IEEE Design Methodologies Conference (DMC), 2024, pp. 1–8, doi: 10.1109/DMC62632.2024.10812131.'
mla: Förster, Nikolas, et al. “Dual-Active Bridge Sequential Pareto Optimization
for Fast Pre-Design and Final Component Selection.” 2024 IEEE Design Methodologies
Conference (DMC), 2024, pp. 1–8, doi:10.1109/DMC62632.2024.10812131.
short: 'N. Förster, O. Wallscheid, F. Schafmeister, in: 2024 IEEE Design Methodologies
Conference (DMC), 2024, pp. 1–8.'
date_created: 2026-01-06T08:06:24Z
date_updated: 2026-01-06T08:07:50Z
department:
- _id: '52'
doi: 10.1109/DMC62632.2024.10812131
keyword:
- MOSFET
- Thermal resistance
- Surface resistance
- Bridge circuits
- Zero voltage switching
- Pareto optimization
- Capacitance
- Numerical simulation
- Optimization
- Resistance heating
- Pareto Optimization
- Dual-Active Bridge
- ZVS
- Inductor Optimization
- Transformer Optimization
- Heat Sink Optimization
language:
- iso: eng
page: 1-8
publication: 2024 IEEE Design Methodologies Conference (DMC)
status: public
title: Dual-Active Bridge Sequential Pareto Optimization for Fast Pre-Design and Final
Component Selection
type: conference
user_id: '83383'
year: '2024'
...
---
_id: '48352'
abstract:
- lang: eng
text: Star-connected cascaded H-bridge Converters require large DC-link capacitors
to buffer the second-order harmonic voltage ripple. First, it is analytically
proven that the DC-link voltage ripple is proportional to the apparent converter
power and does not depend on the power factor for nominal operation with sinusoidal
reference arm voltages and currents. A third-harmonic zero-sequence voltage injection
with an optimal amplitude and phase angle transforms the 2nd harmonic to a 4th
harmonic DC-link voltage ripple. This reduces the voltage ripple by exactly 50%
for all power factors at steady-state at balanced conditions. However, this requires
54% additional modules for unity power factor operation and even 100% for pure
reactive power operation to account for the increased reference arm voltages due
to the large amplitude of the optimal third-harmonic injection. If not enough
modules are available, an adaptive discontinuous PWM is utilized to still minimize
the voltage ripple for the given number of modules and power factor. With a very
limited number of modules (modulation index is 1.15), the proposed method still
reduces the DC-link voltage ripple by 24.4% for unity power factor operation.
It requires the same number of modules as the commonly utilized 3rd harmonic injection
with 1/6 of the grid voltage amplitude and achieves superior results. Simulations
of a 10 kV/1 MVA system confirm the analysis.
author:
- first_name: Roland
full_name: Unruh, Roland
id: '34289'
last_name: Unruh
- first_name: Joachim
full_name: Böcker, Joachim
id: '66'
last_name: Böcker
orcid: 0000-0002-8480-7295
- first_name: Frank
full_name: Schafmeister, Frank
id: '71291'
last_name: Schafmeister
citation:
ama: 'Unruh R, Böcker J, Schafmeister F. An Optimized Third-Harmonic Injection Reduces
DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to 50% for all Power
Factors. In: 2023 25th European Conference on Power Electronics and Applications
(EPE’23 ECCE Europe). IEEE; 2023. doi:10.23919/epe23ecceeurope58414.2023.10264313'
apa: Unruh, R., Böcker, J., & Schafmeister, F. (2023). An Optimized Third-Harmonic
Injection Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to
50% for all Power Factors. 2023 25th European Conference on Power Electronics
and Applications (EPE’23 ECCE Europe). 2023 25th European Conference on Power
Electronics and Applications (EPE’23 ECCE Europe), Aalborg, Denmark. https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313
bibtex: '@inproceedings{Unruh_Böcker_Schafmeister_2023, title={An Optimized Third-Harmonic
Injection Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to
50% for all Power Factors}, DOI={10.23919/epe23ecceeurope58414.2023.10264313},
booktitle={2023 25th European Conference on Power Electronics and Applications
(EPE’23 ECCE Europe)}, publisher={IEEE}, author={Unruh, Roland and Böcker, Joachim
and Schafmeister, Frank}, year={2023} }'
chicago: Unruh, Roland, Joachim Böcker, and Frank Schafmeister. “An Optimized Third-Harmonic
Injection Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to
50% for All Power Factors.” In 2023 25th European Conference on Power Electronics
and Applications (EPE’23 ECCE Europe). IEEE, 2023. https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313.
ieee: 'R. Unruh, J. Böcker, and F. Schafmeister, “An Optimized Third-Harmonic Injection
Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to 50% for all
Power Factors,” presented at the 2023 25th European Conference on Power Electronics
and Applications (EPE’23 ECCE Europe), Aalborg, Denmark, 2023, doi: 10.23919/epe23ecceeurope58414.2023.10264313.'
mla: Unruh, Roland, et al. “An Optimized Third-Harmonic Injection Reduces DC-Link
Voltage Ripple in Cascaded H-Bridge Converters up to 50% for All Power Factors.”
2023 25th European Conference on Power Electronics and Applications (EPE’23
ECCE Europe), IEEE, 2023, doi:10.23919/epe23ecceeurope58414.2023.10264313.
short: 'R. Unruh, J. Böcker, F. Schafmeister, in: 2023 25th European Conference
on Power Electronics and Applications (EPE’23 ECCE Europe), IEEE, 2023.'
conference:
end_date: 2023-09-08
location: Aalborg, Denmark
name: 2023 25th European Conference on Power Electronics and Applications (EPE'23
ECCE Europe)
start_date: 2023-09-04
date_created: 2023-10-20T07:13:32Z
date_updated: 2023-10-20T10:01:02Z
department:
- _id: '52'
doi: 10.23919/epe23ecceeurope58414.2023.10264313
keyword:
- Cascaded H-Bridge
- Solid-State Transformer
- Capacitor voltage ripple
- Zero sequence voltage
- Third harmonic injection
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/10264313
publication: 2023 25th European Conference on Power Electronics and Applications (EPE'23
ECCE Europe)
publication_identifier:
isbn:
- 979-8-3503-1678-0
publication_status: published
publisher: IEEE
quality_controlled: '1'
status: public
title: An Optimized Third-Harmonic Injection Reduces DC-Link Voltage Ripple in Cascaded
H-Bridge Converters up to 50% for all Power Factors
type: conference
user_id: '34289'
year: '2023'
...
---
_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: '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: '4244'
abstract:
- lang: eng
text: In this work we study the resonant and coherent properties of single InP-based
InAs quantum dots, which show an optical emission in the telecom C-band and L-band.
High-resolution resonant photocurrent spectroscopy on p–i–n devices reveals narrow
linewidths and fully resolved fine structure splittings. We observe Lorentzian
line shapes, which allow for the extraction of dephasing times as a function of
the applied bias voltage. Coherent ps laser excitation results in pronounced Rabi
rotations with increasing pulse area. For π-pulse excitation, we obtain more than
93 % of the theoretically expected photocurrent amplitude. Our results also demonstrate
that such state-of-the-art InP-based quantum dots for the telecom band exhibit
promising key parameters comparable to well-established InAs/GaAs counterparts.
article_type: original
author:
- first_name: S.
full_name: Gordon, S.
last_name: Gordon
- first_name: M.
full_name: Yacob, M.
last_name: Yacob
- first_name: J. P.
full_name: Reithmaier, J. P.
last_name: Reithmaier
- first_name: M.
full_name: Benyoucef, M.
last_name: Benyoucef
- first_name: Artur
full_name: Zrenner, Artur
id: '606'
last_name: Zrenner
orcid: 0000-0002-5190-0944
citation:
ama: Gordon S, Yacob M, Reithmaier JP, Benyoucef M, Zrenner A. Coherent photocurrent
spectroscopy of single InP-based quantum dots in the telecom band at 1.5 µm. Applied
Physics B. 2016;122(2). doi:10.1007/s00340-015-6279-6
apa: Gordon, S., Yacob, M., Reithmaier, J. P., Benyoucef, M., & Zrenner, A.
(2016). Coherent photocurrent spectroscopy of single InP-based quantum dots in
the telecom band at 1.5 µm. Applied Physics B, 122(2). https://doi.org/10.1007/s00340-015-6279-6
bibtex: '@article{Gordon_Yacob_Reithmaier_Benyoucef_Zrenner_2016, title={Coherent
photocurrent spectroscopy of single InP-based quantum dots in the telecom band
at 1.5 µm}, volume={122}, DOI={10.1007/s00340-015-6279-6},
number={2}, journal={Applied Physics B}, publisher={Springer Nature}, author={Gordon,
S. and Yacob, M. and Reithmaier, J. P. and Benyoucef, M. and Zrenner, Artur},
year={2016} }'
chicago: Gordon, S., M. Yacob, J. P. Reithmaier, M. Benyoucef, and Artur Zrenner.
“Coherent Photocurrent Spectroscopy of Single InP-Based Quantum Dots in the Telecom
Band at 1.5 Μm.” Applied Physics B 122, no. 2 (2016). https://doi.org/10.1007/s00340-015-6279-6.
ieee: S. Gordon, M. Yacob, J. P. Reithmaier, M. Benyoucef, and A. Zrenner, “Coherent
photocurrent spectroscopy of single InP-based quantum dots in the telecom band
at 1.5 µm,” Applied Physics B, vol. 122, no. 2, 2016.
mla: Gordon, S., et al. “Coherent Photocurrent Spectroscopy of Single InP-Based
Quantum Dots in the Telecom Band at 1.5 Μm.” Applied Physics B, vol. 122,
no. 2, Springer Nature, 2016, doi:10.1007/s00340-015-6279-6.
short: S. Gordon, M. Yacob, J.P. Reithmaier, M. Benyoucef, A. Zrenner, Applied Physics
B 122 (2016).
date_created: 2018-08-29T08:30:59Z
date_updated: 2022-01-06T07:00:41Z
department:
- _id: '15'
- _id: '230'
- _id: '35'
doi: 10.1007/s00340-015-6279-6
intvolume: ' 122'
issue: '2'
keyword:
- Bias Voltage
- Optical Parametric Oscillator
- Molecular Beam Epitaxy Growth
- Internal Electric Field
- Dephasing Time
language:
- iso: eng
publication: Applied Physics B
publication_identifier:
issn:
- 0946-2171
- 1432-0649
publication_status: published
publisher: Springer Nature
status: public
title: Coherent photocurrent spectroscopy of single InP-based quantum dots in the
telecom band at 1.5 µm
type: journal_article
user_id: '49428'
volume: 122
year: '2016'
...
---
_id: '9796'
abstract:
- lang: eng
text: 'A basic autonomous system powered by a piezoelectric harvester contains three
components apart from the harvester: a fullwave rectifier, a reservoir capacitor
and an electronic device performing the primary task of the system. In this contribution,
a model describing the operation of such a system is derived. It is found that
in steady-state operation, the piezoelectric harvester experiences two alternating
load conditions due to the rectification process. These alternating load conditions
can have a significant effect on the operation of the harvester and must be considered
in the design of autonomous systems. The results also show that such an autonomous
system works efficiently if it is connected to a high impedance load and excited
by a frequency matching the anti-resonance frequency of the piezoelectric harvester.'
author:
- first_name: Waleed
full_name: Al-Ashtari, Waleed
last_name: Al-Ashtari
- first_name: Matthias
full_name: Hunstig, Matthias
last_name: Hunstig
- first_name: Tobias
full_name: Hemsel, Tobias
id: '210'
last_name: Hemsel
- first_name: Walter
full_name: Sextro, Walter
id: '21220'
last_name: Sextro
citation:
ama: 'Al-Ashtari W, Hunstig M, Hemsel T, Sextro W. Characteristics of Piezoelectric
Energy Harvesters in Autonomous Systems. In: Proceedings of 10th International
Workshop on Piezoelectric Materials and Applications and 8th Energy Harvesting
Workshop, Hannover, Germany, 14.-17.7.2013. Berichte aus dem IDS. Hannover,
Germany; 2013:159-161.'
apa: Al-Ashtari, W., Hunstig, M., Hemsel, T., & Sextro, W. (2013). Characteristics
of Piezoelectric Energy Harvesters in Autonomous Systems. In Proceedings of
10th International Workshop on Piezoelectric Materials and Applications and 8th
Energy Harvesting Workshop, Hannover, Germany, 14.-17.7.2013 (pp. 159–161).
Hannover, Germany.
bibtex: '@inproceedings{Al-Ashtari_Hunstig_Hemsel_Sextro_2013, place={Hannover,
Germany}, series={Berichte aus dem IDS}, title={Characteristics of Piezoelectric
Energy Harvesters in Autonomous Systems}, number={05/2013}, booktitle={Proceedings
of 10th International Workshop on Piezoelectric Materials and Applications and
8th Energy Harvesting Workshop, Hannover, Germany, 14.-17.7.2013}, author={Al-Ashtari,
Waleed and Hunstig, Matthias and Hemsel, Tobias and Sextro, Walter}, year={2013},
pages={159–161}, collection={Berichte aus dem IDS} }'
chicago: Al-Ashtari, Waleed, Matthias Hunstig, Tobias Hemsel, and Walter Sextro.
“Characteristics of Piezoelectric Energy Harvesters in Autonomous Systems.” In
Proceedings of 10th International Workshop on Piezoelectric Materials and Applications
and 8th Energy Harvesting Workshop, Hannover, Germany, 14.-17.7.2013, 159–61.
Berichte Aus Dem IDS. Hannover, Germany, 2013.
ieee: W. Al-Ashtari, M. Hunstig, T. Hemsel, and W. Sextro, “Characteristics of Piezoelectric
Energy Harvesters in Autonomous Systems,” in Proceedings of 10th International
Workshop on Piezoelectric Materials and Applications and 8th Energy Harvesting
Workshop, Hannover, Germany, 14.-17.7.2013, 2013, no. 05/2013, pp. 159–161.
mla: Al-Ashtari, Waleed, et al. “Characteristics of Piezoelectric Energy Harvesters
in Autonomous Systems.” Proceedings of 10th International Workshop on Piezoelectric
Materials and Applications and 8th Energy Harvesting Workshop, Hannover, Germany,
14.-17.7.2013, no. 05/2013, 2013, pp. 159–61.
short: 'W. Al-Ashtari, M. Hunstig, T. Hemsel, W. Sextro, in: Proceedings of 10th
International Workshop on Piezoelectric Materials and Applications and 8th Energy
Harvesting Workshop, Hannover, Germany, 14.-17.7.2013, Hannover, Germany, 2013,
pp. 159–161.'
date_created: 2019-05-13T13:53:25Z
date_updated: 2022-01-06T07:04:20Z
department:
- _id: '151'
issue: 05/2013
keyword:
- Energy harvesting
- harvester modeling
- load dependence
- generated voltage
language:
- iso: eng
page: 159-161
place: Hannover, Germany
publication: Proceedings of 10th International Workshop on Piezoelectric Materials
and Applications and 8th Energy Harvesting Workshop, Hannover, Germany, 14.-17.7.2013
quality_controlled: '1'
series_title: Berichte aus dem IDS
status: public
title: Characteristics of Piezoelectric Energy Harvesters in Autonomous Systems
type: conference
user_id: '55222'
year: '2013'
...
---
_id: '36920'
abstract:
- lang: eng
text: 'In the electronic system development, energy consumption is clearly becoming
one of the most important design concerns. From the system level point of view,
Dynamic Power Management (DPM) and Dynamic Voltage and Frequency Scaling (DVFS)
are two mostly applied techniques to adjust the tradeoff between the performance
and power dissipation at runtime. In this paper, we study the problem of combined
application of both techniques with regard to hard real-time systems running on
cluster-based multi-core processors. To optimize the processor energy consumption,
a heuristic based on simulated annealing with efficient termination criterion
is proposed. The experiment results show that the proposed algorithm outperforms
the existing approaches in terms of the energy reduction. '
author:
- first_name: Da
full_name: He, Da
last_name: He
- first_name: Wolfgang
full_name: Müller, Wolfgang
id: '16243'
last_name: Müller
citation:
ama: 'He D, Müller W. An Energy-Efficient Heuristic for Hard Real-Time System on
Multi-Core Processors. In: Weghorn H, ed. Proceedings of the International
Conference on Applied Computing (AC). ; 2013.'
apa: He, D., & Müller, W. (2013). An Energy-Efficient Heuristic for Hard Real-Time
System on Multi-Core Processors. In H. Weghorn (Ed.), Proceedings of the International
Conference on Applied Computing (AC).
bibtex: '@inproceedings{He_Müller_2013, place={Fort Worth, Texas, USA}, title={An
Energy-Efficient Heuristic for Hard Real-Time System on Multi-Core Processors},
booktitle={Proceedings of the International Conference on Applied Computing (AC)},
author={He, Da and Müller, Wolfgang}, editor={Weghorn, Hans}, year={2013} }'
chicago: He, Da, and Wolfgang Müller. “An Energy-Efficient Heuristic for Hard Real-Time
System on Multi-Core Processors.” In Proceedings of the International Conference
on Applied Computing (AC), edited by Hans Weghorn. Fort Worth, Texas, USA,
2013.
ieee: D. He and W. Müller, “An Energy-Efficient Heuristic for Hard Real-Time System
on Multi-Core Processors,” in Proceedings of the International Conference on
Applied Computing (AC), 2013.
mla: He, Da, and Wolfgang Müller. “An Energy-Efficient Heuristic for Hard Real-Time
System on Multi-Core Processors.” Proceedings of the International Conference
on Applied Computing (AC), edited by Hans Weghorn, 2013.
short: 'D. He, W. Müller, in: H. Weghorn (Ed.), Proceedings of the International
Conference on Applied Computing (AC), Fort Worth, Texas, USA, 2013.'
date_created: 2023-01-16T12:12:58Z
date_updated: 2023-01-16T12:15:44Z
department:
- _id: '672'
editor:
- first_name: Hans
full_name: Weghorn, Hans
last_name: Weghorn
keyword:
- Dynamic Power Management
- Dynamic Voltage and Frequency Scaling
- Hard Real-Time
- Multi-core Processor
language:
- iso: eng
place: Fort Worth, Texas, USA
publication: Proceedings of the International Conference on Applied Computing (AC)
publication_identifier:
isbn:
- '978-989-8533-20-3 '
status: public
title: An Energy-Efficient Heuristic for Hard Real-Time System on Multi-Core Processors
type: conference
user_id: '5786'
year: '2013'
...
---
_id: '9568'
abstract:
- lang: eng
text: A simple pre-stress estimate method of Langevin transducers is studied. The
measurement setup consists of a capacitor, an impedance converter and a voltmeter.
Based on the piezoelectric equation and the basic circuit theory, the mathematical
expression between the pre-stress and the voltage across the capacitor is derived.
The pre-stress level can then be calculated out of the measurement of the capacitor
voltage. In order to evaluate the precision of this method, a force washer is
used to measure the pre-stress of the Langevin transducer. The result shows the
pre-stress level obtained from this method is 30-40\% higher than the pre-stress
level measured by the force washer. This method is simple and can be used to estimate
the pre-stress of various Langevin transducers. The precision of this method can
be raised if d33 is identified under different pre-stress levels.
author:
- first_name: Fu
full_name: Bo, Fu
last_name: Bo
- first_name: Li
full_name: Ting, Li
last_name: Ting
- first_name: Tobias
full_name: Hemsel, Tobias
id: '210'
last_name: Hemsel
citation:
ama: 'Bo F, Ting L, Hemsel T. A simple pre-stress estimating method of langevin
transducers. In: Piezoelectricity, Acoustic Waves, and Device Applications,
2008. SPAWDA 2008. Symposium On. ; 2008:324-327. doi:10.1109/SPAWDA.2008.4775801'
apa: Bo, F., Ting, L., & Hemsel, T. (2008). A simple pre-stress estimating method
of langevin transducers. In Piezoelectricity, Acoustic Waves, and Device Applications,
2008. SPAWDA 2008. Symposium on (pp. 324–327). https://doi.org/10.1109/SPAWDA.2008.4775801
bibtex: '@inproceedings{Bo_Ting_Hemsel_2008, title={A simple pre-stress estimating
method of langevin transducers}, DOI={10.1109/SPAWDA.2008.4775801},
booktitle={Piezoelectricity, Acoustic Waves, and Device Applications, 2008. SPAWDA
2008. Symposium on}, author={Bo, Fu and Ting, Li and Hemsel, Tobias}, year={2008},
pages={324–327} }'
chicago: Bo, Fu, Li Ting, and Tobias Hemsel. “A Simple Pre-Stress Estimating Method
of Langevin Transducers.” In Piezoelectricity, Acoustic Waves, and Device Applications,
2008. SPAWDA 2008. Symposium On, 324–27, 2008. https://doi.org/10.1109/SPAWDA.2008.4775801.
ieee: F. Bo, L. Ting, and T. Hemsel, “A simple pre-stress estimating method of langevin
transducers,” in Piezoelectricity, Acoustic Waves, and Device Applications,
2008. SPAWDA 2008. Symposium on, 2008, pp. 324–327.
mla: Bo, Fu, et al. “A Simple Pre-Stress Estimating Method of Langevin Transducers.”
Piezoelectricity, Acoustic Waves, and Device Applications, 2008. SPAWDA 2008.
Symposium On, 2008, pp. 324–27, doi:10.1109/SPAWDA.2008.4775801.
short: 'F. Bo, L. Ting, T. Hemsel, in: Piezoelectricity, Acoustic Waves, and Device
Applications, 2008. SPAWDA 2008. Symposium On, 2008, pp. 324–327.'
date_created: 2019-04-29T11:16:13Z
date_updated: 2022-01-06T07:04:16Z
department:
- _id: '151'
doi: 10.1109/SPAWDA.2008.4775801
keyword:
- capacitors
- impedance convertors
- piezoelectric transducers
- stress analysis
- Langevin transducers
- basic circuit theory
- capacitor
- impedance converter
- piezoelectric equation
- pre-stress estimating method
- voltmeter
- Capacitors
- Educational institutions
- Equations
- Force measurement
- Impedance measurement
- Manufacturing
- Mechatronics
- Piezoelectric transducers
- Voltage
- Voltmeters
- Langevin transducer
- capacitor
- piezoelectric element
- pre-stress
language:
- iso: eng
page: 324-327
publication: Piezoelectricity, Acoustic Waves, and Device Applications, 2008. SPAWDA
2008. Symposium on
status: public
title: A simple pre-stress estimating method of langevin transducers
type: conference
user_id: '55222'
year: '2008'
...
---
_id: '9576'
abstract:
- lang: eng
text: 'In neurosurgery, delineation of tumor boundaries during resection of brain
tumors is of substantial relevance. During operation distinction between tumor
and healthy tissue rely on the abilities of the surgeon based on visual and tactile
differentiation. In this paper a high sensitivity actuator-sensor system using
a piezoelectric bimorph is presented. Frequency shift and transfer function of
the bimorphpsilas voltages are detected and evaluated. Sensorpsilas sensitivity
is evaluated using two frequency controls strategies: A phase-locked loop (PLL)
and a self-oscillating circuit. Results of measurements conducted on gel-phantoms
are presented and discussed.'
author:
- first_name: David Oliva
full_name: Uribe, David Oliva
last_name: Uribe
- first_name: Ralf
full_name: Stroop, Ralf
last_name: Stroop
- first_name: Tobias
full_name: Hemsel, Tobias
id: '210'
last_name: Hemsel
- first_name: Jörg
full_name: Wallaschek, Jörg
last_name: Wallaschek
citation:
ama: 'Uribe DO, Stroop R, Hemsel T, Wallaschek J. Development of a biomedical tissue
differentiation system using piezoelectric actuators. In: Frequency Control
Symposium, 2008 IEEE International. ; 2008:91-94. doi:10.1109/FREQ.2008.4622963'
apa: Uribe, D. O., Stroop, R., Hemsel, T., & Wallaschek, J. (2008). Development
of a biomedical tissue differentiation system using piezoelectric actuators. In
Frequency Control Symposium, 2008 IEEE International (pp. 91–94). https://doi.org/10.1109/FREQ.2008.4622963
bibtex: '@inproceedings{Uribe_Stroop_Hemsel_Wallaschek_2008, title={Development
of a biomedical tissue differentiation system using piezoelectric actuators},
DOI={10.1109/FREQ.2008.4622963},
booktitle={Frequency Control Symposium, 2008 IEEE International}, author={Uribe,
David Oliva and Stroop, Ralf and Hemsel, Tobias and Wallaschek, Jörg}, year={2008},
pages={91–94} }'
chicago: Uribe, David Oliva, Ralf Stroop, Tobias Hemsel, and Jörg Wallaschek. “Development
of a Biomedical Tissue Differentiation System Using Piezoelectric Actuators.”
In Frequency Control Symposium, 2008 IEEE International, 91–94, 2008. https://doi.org/10.1109/FREQ.2008.4622963.
ieee: D. O. Uribe, R. Stroop, T. Hemsel, and J. Wallaschek, “Development of a biomedical
tissue differentiation system using piezoelectric actuators,” in Frequency
Control Symposium, 2008 IEEE International, 2008, pp. 91–94.
mla: Uribe, David Oliva, et al. “Development of a Biomedical Tissue Differentiation
System Using Piezoelectric Actuators.” Frequency Control Symposium, 2008 IEEE
International, 2008, pp. 91–94, doi:10.1109/FREQ.2008.4622963.
short: 'D.O. Uribe, R. Stroop, T. Hemsel, J. Wallaschek, in: Frequency Control Symposium,
2008 IEEE International, 2008, pp. 91–94.'
date_created: 2019-04-29T13:07:39Z
date_updated: 2022-01-06T07:04:16Z
department:
- _id: '151'
doi: 10.1109/FREQ.2008.4622963
keyword:
- biomedical measurement
- brain
- cancer
- neurophysiology
- phantoms
- phase locked loops
- piezoelectric actuators
- surgery
- tactile sensors
- transfer functions
- tumours
- PLL
- biomedical tissue differentiation system
- brain tumor resection
- frequency control
- frequency shift
- gel-phantom
- high sensitivity actuator-sensor system
- neurosurgery
- phase-locked loop
- piezoelectric actuators
- piezoelectric bimorph
- self-oscillating circuit
- sensor sensitivity
- tactile differentiation
- tactile sensor system
- transfer function
- tumor boundary
- visual differentiation
- Biomedical measurements
- Circuits
- Frequency control
- Neoplasms
- Neurosurgery
- Phase locked loops
- Piezoelectric actuators
- Surges
- Transfer functions
- Voltage
language:
- iso: eng
page: 91-94
publication: Frequency Control Symposium, 2008 IEEE International
publication_identifier:
issn:
- 1075-6787
quality_controlled: '1'
status: public
title: Development of a biomedical tissue differentiation system using piezoelectric
actuators
type: conference
user_id: '55222'
year: '2008'
...
---
_id: '9519'
abstract:
- lang: eng
text: 'Several positioning tasks demand translatory drive instead of rotary motion.
To achieve drives that are capable e.g. to drive the sunroof of a car or to lift
a car''s window, multiple miniaturized motors can be combined. But in this case
many other questions arise: the electromechanical behavior of the individual motors
differs slightly, the motor characteristics are strongly dependent on the driving
parameters and the driven load, many applications need some extra power for special
cases like overcoming higher forces periodically. Thus, the bundle of motors has
to act well organized and controlled to get an optimized drive that is not oversized
and costly.'
author:
- first_name: Tobias
full_name: Hemsel, Tobias
id: '210'
last_name: Hemsel
- first_name: Maik
full_name: Mracek, Maik
last_name: Mracek
- first_name: Jörg
full_name: Wallaschek, Jörg
last_name: Wallaschek
- first_name: Piotr
full_name: Vasiljev, Piotr
last_name: Vasiljev
citation:
ama: 'Hemsel T, Mracek M, Wallaschek J, Vasiljev P. A novel approach for high power
ultrasonic linear motors. In: Ultrasonics Symposium, 2004 IEEE. Vol 2.
; 2004:1161-1164. doi:10.1109/ULTSYM.2004.1417988'
apa: Hemsel, T., Mracek, M., Wallaschek, J., & Vasiljev, P. (2004). A novel
approach for high power ultrasonic linear motors. In Ultrasonics Symposium,
2004 IEEE (Vol. 2, pp. 1161–1164). https://doi.org/10.1109/ULTSYM.2004.1417988
bibtex: '@inproceedings{Hemsel_Mracek_Wallaschek_Vasiljev_2004, title={A novel approach
for high power ultrasonic linear motors}, volume={2}, DOI={10.1109/ULTSYM.2004.1417988},
number={Vol.2}, booktitle={Ultrasonics Symposium, 2004 IEEE}, author={Hemsel,
Tobias and Mracek, Maik and Wallaschek, Jörg and Vasiljev, Piotr}, year={2004},
pages={1161–1164} }'
chicago: Hemsel, Tobias, Maik Mracek, Jörg Wallaschek, and Piotr Vasiljev. “A Novel
Approach for High Power Ultrasonic Linear Motors.” In Ultrasonics Symposium,
2004 IEEE, 2:1161–64, 2004. https://doi.org/10.1109/ULTSYM.2004.1417988.
ieee: T. Hemsel, M. Mracek, J. Wallaschek, and P. Vasiljev, “A novel approach for
high power ultrasonic linear motors,” in Ultrasonics Symposium, 2004 IEEE,
2004, vol. 2, no. Vol.2, pp. 1161–1164.
mla: Hemsel, Tobias, et al. “A Novel Approach for High Power Ultrasonic Linear Motors.”
Ultrasonics Symposium, 2004 IEEE, vol. 2, no. Vol.2, 2004, pp. 1161–64,
doi:10.1109/ULTSYM.2004.1417988.
short: 'T. Hemsel, M. Mracek, J. Wallaschek, P. Vasiljev, in: Ultrasonics Symposium,
2004 IEEE, 2004, pp. 1161–1164.'
date_created: 2019-04-29T08:12:06Z
date_updated: 2022-01-06T07:04:16Z
department:
- _id: '151'
doi: 10.1109/ULTSYM.2004.1417988
intvolume: ' 2'
issue: Vol.2
keyword:
- drives
- electromechanical effects
- linear motors
- ultrasonic motors
- car sunroof
- car window
- electromechanical behavior
- high power ultrasonic linear motors
- multiple miniaturized motors
- positioning tasks
- translatory drive
- Costs
- Electromagnetic forces
- Frequency
- Laboratories
- Manufacturing
- Mechatronics
- Micromotors
- Ultrasonic imaging
- Vibrations
- Voltage
language:
- iso: eng
page: 1161-1164
publication: Ultrasonics Symposium, 2004 IEEE
publication_identifier:
issn:
- 1051-0117
quality_controlled: '1'
status: public
title: A novel approach for high power ultrasonic linear motors
type: conference
user_id: '55222'
volume: 2
year: '2004'
...