@inproceedings{RauchBrueckl, author = {Rauch, Johannes and Br{\"u}ckl, Oliver}, title = {Analysis of the correlation behavior between local available information to the overall reactive power of a medium-voltage grid group}, series = {Applied Research Conference - ARC 2017, 7 July 2017 M{\"u}nchen}, booktitle = {Applied Research Conference - ARC 2017, 7 July 2017 M{\"u}nchen}, address = {M{\"u}nchen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-58712}, pages = {224 -- 230}, abstract = {The initiated energy transition leads to extensive changes in the supply of energy. The increasing use of renewable energy causes a shift of the produced power from centralized conventional power plants to decentralized energy plants. Because of this redistribution and the related change of load-flows, new challenges and problems for distribution system operators appear. This includes the integration of new loads and plants into the existing power grid and the guarantee of a high supply security and quality. It also includes strengthened requirements for the use and provision of reactive power. The project "SyNErgie" ("Systemoptimierendes Netz- und Energiemanagement f{\"u}r Verteilungsnetze der Zukunft") deals with the development of a new reactive power management, which gets embedded in grid planning and controlling processes. One focus of the project is on the integration of decentralized energy plants (DEPs) to the reactive power management. The aim is to develop a decentralized and self-sufficient reactive power control system, which only works with local available information (measures). Therefore is no necessity of a complex communication system to the grid control center. Self-controlled Q-controller in the DEPs get characteristic curves and control the reactive power sources with local measurements (e.g. current, voltage, effective power). This new reactive power control management aims for the reactive power compensation in order to increase the integration capacity of loads and plants in a grid [2]. In order to generate characteristic curves for DEPs, it is necessary to analyze the correlation behavior between the local available measurements at the DEPs and the overall-Q-behavior of the grid group at the transformer. In that regard, influencing quantities should be considered. The aim is to involve und evaluate all relevant influencing quantities in order to determine energy plants and certain operating points, in which the correlation behavior and the prediction for the overall-Q-behavior are sufficient. The next step is to develop a model that fits these correlation behaviors and generate characteristic curves. One method to generate characteristic curves for the Q-controllers is regression analysis. The developed Q-control-system with the characteristic curves will be tested, evaluated and optimized in a following field test in cooperation with distribution system operators.}, language = {de} } @article{MalzKrenkelSteffens, author = {Malz, Sebastian and Krenkel, Walter and Steffens, Oliver}, title = {Infrared Reflective Wall Paint in Buildings: Energy Saving Potentials and Thermal Comfort}, series = {Energy and Buildings}, volume = {224}, journal = {Energy and Buildings}, number = {October}, publisher = {Elsevier}, issn = {0378-7788}, doi = {10.1016/j.enbuild.2020.110212}, abstract = {The reduction of the energy demand of existing buildings is the main objective of building refurbishment. Managing the heat radiation properties of the wall construction is a possible way to develop highly effective and resource efficient insulation materials and concepts. The application of infrared reflective wall paints and coatings has been studied since the latter half of the 20th century. A brief review of the literature gives an account of the current research status. One has to realise that the conclusions are not uniformly consistent but depend strongly on the specific boundary conditions and investigated parameters. The study presented here discusses the usage of infrared reflective wall paint in conjunction with heat insulation for historic brick masonry. The possible energy savings are linked to the resulting thermal comfort. We identify critical parameters that must be taken into account when using infrared reflective wall paint and derive recommended design rules for the refurbishment of such building types. The findings prove that infrared reflective wall paint can decrease heat losses by 18\% and up to 22\% if comfort conditions are considered. Increasing energy savings can also cause the negative effect of high radiative asymmetry. Thus, each configuration must be observed in detail.}, language = {en} } @techreport{SternerSchummRanketal., author = {Sterner, Michael and Schumm, Leon and Rank, Daniel and Hofrichter, Andreas}, title = {Intelligente Netzpuffer : Abschlussbericht (24.01.2021)}, language = {de} } @article{SchulzSchwarz, author = {Schulz, Carsten and Schwarz, Colin}, title = {Drivetrain fatigue strength characteristics of model-predictive control for wind turbines}, series = {Wind Energy}, volume = {23}, journal = {Wind Energy}, number = {12}, publisher = {Wiley}, doi = {10.1002/we.2520}, pages = {2137 -- 2149}, abstract = {Wind turbines play a crucial role in the revolution towards renewable resources. They need to be economically competitive to be sustainable. This still requires to lower the cost of energy (COE). To this end, nonlinear model predictive control (NMPC) is used within this paper. As known from literature, NMPC significantly improves the energy extracting performance as well as the mitigation of tower loads of wind turbines. As it is shown in this paper, the drivetrain fatigue strength drops disproportionally in parallel, which either increases the demands on the turbine design or decreases the lifetime of drivetrain components. Without additional boundary conditions to the underlying optimal control problems (OCPs), the application of energy-maximizing NMPC might so even raise the COE. Only penalizing axial torque oscillations by quadratic terms decreases energy-extracting performance below the level of classical wind turbine controllers. This makes more sophisticated conditions necessary. In this paper, the increase of the drivetrain damage by NMPC is analyzed, and appropriate boundary conditions are derived, to balance the two contradicting objectives of energy maximization and drivetrain load mitigation. An NMPC approach based on indirect methods is used, to obtain a solution of the OCPs very efficiently. It applies the Hamilton equations and Pontryagin's maximum principle. Its accuracy and efficiency to solve OCPs was presented over the last decades.}, language = {en} } @article{HaumerKralVukovicetal., author = {Haumer, Anton and Kral, Christian and Vukovic, Vladimir and David, Alexander and Hettfleisch, Christian and Huzsvar, Attila}, title = {A Parametrization Scheme for High Performance Thermal Models of Electric Machines using Modelica}, series = {IFAC Proceedings Volumes}, volume = {45}, journal = {IFAC Proceedings Volumes}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1474-6670}, doi = {10.3182/20120215-3-AT-3016.00187}, pages = {1058 -- 1062}, abstract = {Thermal models offer great advantages for enhancement of design, protection and control of electric machines. Detailed thermal models take a great number of time constants into account and provide accurate prediction of the temperatures. However, to parameterize such models detailed geometric data are needed. Whenever such detailed information is not available, or the performance of the detailed models is not satisfying, simplified thermal models as described in this paper are advantageous. The calculation of parameters is described in detail, in order to achieve best accordance with temperatures obtained from measurements or from simulations with detailed thermal models. Thermal resistances are calculated from end temperatures of a test run with constant load (and known losses). Thermal capacitances are obtained using optimization to minimize deviation of simulated and measured temperatures during the whole test run. The thermal model of an asynchronous induction machine with squirrel cage is coupled with an electrical model of the drive. For validation, simulation results of an optimally parameterized simplified model are compared with temperatures obtained by simulation of a detailed thermal model, which in turn has been validated against measurement results, both for continuous duty S1 and intermittent duty S6 (6 minutes no-load followed by 4 minutes of 140\% nominal load). The deviations are not more than 4 K which is quite satisfying.}, language = {en} } @article{KralHaumerHaigisetal., author = {Kral, Christian and Haumer, Anton and Haigis, Matthias and Lang, Hermann and Kapeller, Hansj{\"o}rg}, title = {Comparison of a CFD Analysis and a Thermal Equivalent Circuit Model of a TEFC Induction Machine With Measurements}, series = {IEEE Transactions on Energy Conversion}, volume = {24}, journal = {IEEE Transactions on Energy Conversion}, number = {4}, publisher = {IEEE}, issn = {0885-8969}, doi = {10.1109/TEC.2009.2025428}, pages = {809 -- 818}, abstract = {For a totally enclosed fan-cooled induction machine, two methods of numerical analysis are compared with measurements. The first numerical method is based on computational fluid dynamics (CFDs) and the second one uses a thermal equivalent circuit (TEC). For the analysis based on CFD, a 3-D induction machine including housing is modeled. The numeric solution of the flow equations is determined for stationary temperature distributions. For the TEC, a discretized one-and-a-half-dimensional model of the induction machine is considered. With the TEC model, stationary and transient operating conditions can be simulated. Measurement results are determined by iron-copper-nickel sensors embedded in the stator winding and the housing, as well as by an IR sensor for measuring the rotor temperature. With these measurement signals, stationary and transient operating conditions can be analyzed. For stationary operating conditions, additionally, the housing temperatures are determined by an IR camera. The investigated simulation and measurement methods reveal different local and global temperatures, and thus, only certain aspects and characteristics of the obtained temperatures can be compared. Nevertheless, certain conclusions can be drawn from comparing these aspects considering the actual restrictions of each of the applied methods.}, language = {en} } @article{KralKapellerGraggeretal., author = {Kral, Christian and Kapeller, Hansj{\"o}rg and Gragger, Johannes V. and Haumer, Anton and Kubicek, Bernhard}, title = {Phenomenon Rotor Fault-Multiple Electrical Rotor Asymmetries in Induction Machines}, series = {IEEE Transactions on Power Electronics}, volume = {25}, journal = {IEEE Transactions on Power Electronics}, number = {5}, publisher = {IEEE}, issn = {0885-8993}, doi = {10.1109/TPEL.2009.2037502}, pages = {1124 -- 1134}, abstract = {In the literature, the effects caused by a single or several adjacently broken rotor bars, or a broken end ring are thoroughly investigated. The phenomenon of various nonadjacently broken rotor bars has not been studied so far in detail. Since nonadjacently broken rotor bars may give rise to fault signatures, which are not directly related with the fault extent, it is important to understand the nature of multiple electrical rotor asymmetries in induction machines. The purpose of this paper is thus to investigate several combinations of electrical rotor asymmetries, to systematically elaborate the phenomena related to the broken bars and end rings. In this paper, a sophisticated simulation model and measurement results are used to analyze the phenomenon rotor fault.}, language = {en} } @inproceedings{EbnerHaumerSimicetal., author = {Ebner, Arno and Haumer, Anton and Simic, Dragan and Pirker, Franz}, title = {Interacting Modelica using a Named Pipe for Hardware-in-the-loop Simulation}, series = {Modelica 2006, Conference proceedings / 5th International Modelica Conference : September 4 - 5, 2006, Vienna, Austria}, booktitle = {Modelica 2006, Conference proceedings / 5th International Modelica Conference : September 4 - 5, 2006, Vienna, Austria}, pages = {261 -- 266}, abstract = {The paper presents a concept and an implementation of Modelica simulation interaction using the operating system inter-process communication method of the Named Pipe. The main aim of this presented work is to implement a hardware-in-the-loop simulation (HILS) environment based on Dymola which runs on a normal Microsoft Windows Personal Com-puter. An energy storage test bench is connected by an ana-logue and digital data input/output card with the Dymola simulation computer. With this proposed system, particularly long-time simulations with sample rates up to 30 Hz can be executed very cost effective. Typical applications are simulations of drive cycles to test energy storage systems in electrified vehicles such as batteries or fuel cells. Other application ex-amples are the verification of battery models, thermal management models or battery management sys-tem (BMS) models. In this paper all methods used for implementation are described in detail. Especially the concept of inter-process communication and the concept for real-time and simulation time synchronization is discused. An application example which uses the provided concept is also shown at in this paper. In this example a longitudinal simulation of a vehicle is pre-sented. The startup phase of the internal combusting engine model and a short drive cycle in combination with a connected real battery is shown.}, language = {en} } @inproceedings{BaeumlHaumerKapelleretal., author = {B{\"a}uml, T. and Haumer, Anton and Kapeller, H. and Starzinger, J. and Farzi, P.}, title = {Impact of inverter pulse inhibition on the high-voltage supply system of an electric vehicle — A simulative approach}, series = {2011 IEEE Vehicle Power and Propulsion Conference (VPPC 2011) : Powering sustainable transportation ; Chicago, Illinois, USA, 06. - 09.09.2011}, booktitle = {2011 IEEE Vehicle Power and Propulsion Conference (VPPC 2011) : Powering sustainable transportation ; Chicago, Illinois, USA, 06. - 09.09.2011}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-61284-248-6}, doi = {10.1109/VPPC.2011.6043159}, pages = {1 -- 5}, abstract = {This paper deals with a simulative approach for investigating the impact of inverter pulse inhibition during field weakening operation of permanent magnet synchronous machines and asynchronous induction machines. The modelling and simulation language Modelica is used to design models for the vehicle, the electric machine and the inverter in different abstraction levels. It is shown that when using a permanent magnet synchronous machine, a sudden breakdown of the field weakening current causes induction of high voltages in the stator windings. Hence, the electric system of the vehicle has to be protected against the resulting high currents. Furthermore precautions have to be taken to avoid dangerous driving conditions because of high braking torques in an inverter fault operation mode. In the case of the asynchronous induction machine an inverter pulse inhibition poses no big problem, neither for the electric system of the vehicle, nor the driver.}, language = {en} } @inproceedings{BogomolovKralHaumeretal., author = {Bogomolov, Maxim and Kral, Christian and Haumer, Anton and Lomonova, Elena}, title = {Modeling of permanent magnet synchronous machine with fractional slot windings}, series = {Proceedings IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society ; Ecole de Technologie Superieure de Montreal, Universite du Quebec Montreal, Canada 25 - 28 October, 2012}, booktitle = {Proceedings IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society ; Ecole de Technologie Superieure de Montreal, Universite du Quebec Montreal, Canada 25 - 28 October, 2012}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-4673-2421-2}, issn = {1553-572X}, doi = {10.1109/IECON.2012.6388912}, pages = {1894 -- 1899}, abstract = {This paper focuses on simulation of permanent magnet synchronous machine (PMSM) with fractional-slot windings (FSW) in Modelica. Modeling of the electrical machines with object-oriented approach is shortly described, and a new Modelica library for simulation of electrical machines is introduced. The results of simulation of PMSMs with fractional slot windings are presented and explained. Special attention is paid to the higher harmonics and subharmonics produced by the winding and their influence on machine operation.}, language = {en} }