@misc{HerrmannPlietzschRoseetal., author = {Herrmann, Ulrike and Plietzsch, Anton and Rose, Max and Gernandt, Hannes and Schiffer, Johannes}, title = {A predictive operation management scheme for hydrogen networks based on the method of characteristics}, series = {2024 European Control Conference (ECC)}, journal = {2024 European Control Conference (ECC)}, publisher = {IEEE}, doi = {10.23919/ECC64448.2024.10591107}, pages = {1084 -- 1089}, abstract = {As future hydrogen networks will be strongly linked to the electricity system via electrolysers and hydrogen power plants, challenges will arise for their operation. A suitable response to phenomena, such as rapidly changing boundary conditions and unbalanced supply and demand, requires the implementation of operational concepts based on transient pipe models. The transient pipe flow can be described by the isothermal Euler equations, which we discretize using an explicit Method Of Characteristics. Based on this, we develop a nonlinear space-time discretized network model that incorporates various other components, including hydrogen storage facilities, active elements such as valves and compressor stations, as well as electrolyzers and fuel cells. This network model serves as the foundation for the development of a tailored economic model predictive control algorithm designed for fast timescales. The algorithm enables controlled pressure changes within specified bounds in response to changes in supply and demand while simultaneously minimizing fast pressure fluctuations in the pipelines. Through a detailed case study, we demonstrate the algorithm's proficiency in addressing these transient operation challenges.}, language = {en} } @misc{RoseHansSchiffer, author = {Rose, Max and Hans, Christian A. and Schiffer, Johannes}, title = {A Predictive Operation Controller for an Electro-Thermal Microgrid Utilizing Variable Flow Temperatures}, series = {IFAC-PapersOnLine}, volume = {56}, journal = {IFAC-PapersOnLine}, number = {2}, issn = {2405-8963}, doi = {10.1016/j.ifacol.2023.10.195}, pages = {5444 -- 5450}, abstract = {We propose an optimal operation controller for an electro-thermal microgrid. Compared to existing work, our approach increases flexibility by operating the thermal network with variable flow temperatures and in that way explicitly exploits its inherent storage capacities. To this end, the microgrid is represented by a multi-layer network composed of an electrical and a thermal layer. We show that the system behavior can be represented by a discrete-time state model derived from DC power flow approximations and 1d Euler equations. Both layers are interconnected via heat pumps. By combining this model with desired operating objectives and constraints, we obtain a constrained convex optimization problem. This is used to derive a model predictive control scheme for the optimal operation of electro-thermal microgrids. The performance of the proposed operation control algorithm is demonstrated in a case study.}, language = {en} } @misc{RoseGernandtFaulwasseretal., author = {Rose, Max and Gernandt, Hannes and Faulwasser, Timm and Schiffer, Johannes}, title = {Exact time-varying turnpikes for dynamic operation of district heating networks}, series = {IEEE control systems letters}, volume = {9}, journal = {IEEE control systems letters}, publisher = {IEEE}, address = {New York, NY}, issn = {2475-1456}, doi = {10.1109/LCSYS.2025.3582614}, pages = {1706 -- 1711}, abstract = {District heating networks (DHNs) are crucial for decarbonizing the heating sector. Yet, their efficient and reliable operation requires the coordination of multiple heat producers and the consideration of future demands. Predictive and optimization-based control is commonly used to address this task, but existing results for DHNs do not account for time-varying problem aspects. Since the turnpike phenomenon can serve as a basis for model predictive control design and analysis, this letter examines its role in DHN optimization by analyzing the underlying optimal control problem with time-varying prices and demands. That is, we derive conditions for the existence of a unique time-varying singular arc, which constitutes the time varying turnpike, and we provide its closed-form expression. Additionally, we present converse turnpike results showing a exact time-varying case implies strict dissipativity of the optimal control problem. A numerical example illustrates our findings.}, language = {en} }