@inproceedings{HahnBurkhardtSemerowetal., author = {Hahn, Christoph and Burkhardt, Matthias and Semerow, Anatoli and Luther, Matthias and Ruhle, Olaf}, title = {Generic modeling of a self-commutated multilevel VSC HVDC system for power system stability studies}, series = {2015 IEEE Applied Power Electronics Conference and Exposition}, booktitle = {2015 IEEE Applied Power Electronics Conference and Exposition}, publisher = {IEEE Computer Society Press}, isbn = {978-1-4799-6735-3}, doi = {10.1109/apec.2015.7104728}, abstract = {This paper provides a generic stability model of a self-commutated multilevel VSC (Voltage Source Converter) HVDC (High Voltage Direct Current) and its appropriate control. At first the approach of modeling depicts the independence of the AC and DC quantities and therefore two separate models - one for the AC and one for the DC side - can be figured out. The AC side model is developed in the dq frame out of the according differential equations. For the DC side no further transformation is required. Regarding the fact of balanced energy terms the two models can be merged. The consolidation of both models reveals a comprehensive large signal model of a multilevel based HVDC system which can be used for detailed analyses in power system stability studies. Due to the comparison of the generic stability model with an EMT (Electro-Magnetic Transient) HVDC model the consistence of the dynamic behavior is shown.}, language = {en} } @inproceedings{HahnSemerowLutheretal., author = {Hahn, Christoph and Semerow, Anatoli and Luther, Matthias and Ruhle, Olaf}, title = {Generic modeling of a line commutated HVDC system for power system stability studies}, series = {Proceedings of the IEEE Power Engineering Society Transmission and Distribution Conference}, booktitle = {Proceedings of the IEEE Power Engineering Society Transmission and Distribution Conference}, publisher = {Institute of Electrical and Electronics Engineers}, isbn = {978-1-4799-3655-7}, doi = {10.1109/TDC.2014.6863308}, abstract = {This paper will reveal a novel comprehensive approach for generic modeling and control design of line commutated HVDC systems. The model will be developed based on the essential HVDC equations and transfer functions. Due to comparing the generic model with an EMT (Electro-Magnetic Transient) HVDC model the consistence of the dynamic behavior will be shown. Furthermore modeling of additional HVDC system facilities like transformer tap-changers and AC filters will be annotated. Control design schemes for line commutated HVDC systems will be derived and the interactions of the controllers applied to the developed model will be investigated. © 2014 IEEE.}, language = {en} } @article{GenslerMalkmusOckermannetal., author = {Gensler, Marius and Malkmus, Christoph and Ockermann, Philipp and M{\"o}llmann, Marc and Hahn, Lukas and Salehi, Sahar and Luxenhofer, Robert and Boccaccini, Aldo R. and Hansmann, Jan}, title = {Perfusable Tissue Bioprinted into a 3D-Printed Tailored Bioreactor System}, series = {Bioengineering}, volume = {11}, journal = {Bioengineering}, number = {1}, publisher = {MDPI}, issn = {2306-5354}, doi = {10.3390/bioengineering11010068}, pages = {16}, abstract = {Bioprinting provides a powerful tool for regenerative medicine, as it allows tissue construction with a patient's specific geometry. However, tissue culture and maturation, commonly supported by dynamic bioreactors, are needed. We designed a workflow that creates an implant-specific bioreactor system, which is easily producible and customizable and supports cell cultivation and tissue maturation. First, a bioreactor was designed and different tissue geometries were simulated regarding shear stress and nutrient distribution to match cell culture requirements. These tissues were then directly bioprinted into the 3D-printed bioreactor. To prove the ability of cell maintenance, C2C12 cells in two bioinks were printed into the system and successfully cultured for two weeks. Next, human mesenchymal stem cells (hMSCs) were successfully differentiated toward an adipocyte lineage. As the last step of the presented strategy, we developed a prototype of an automated mobile docking station for the bioreactor. Overall, we present an open-source bioreactor system that is adaptable to a wound-specific geometry and allows cell culture and differentiation. This interdisciplinary roadmap is intended to close the gap between the lab and clinic and to integrate novel 3D-printing technologies for regenerative medicine.}, language = {en} }