@inproceedings{63496, author = {{Foerster, Nikolas and Urbaneck, Daniel and Schenke, Maximilian and Ebers, Anastacia and Schoenlau, Nicolas and Wallscheid, Oliver and Schafmeister, Frank}}, booktitle = {{PCIM Conference 2025; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management}}, pages = {{2881--2890}}, title = {{{Improving the Usability of Calorimetric Measuring Chambers for Reliable Thermal Measurements}}}, doi = {{10.30420/566541386}}, year = {{2025}}, } @inproceedings{65097, author = {{Weber, Daniel and Lange, Jarren and Wallscheid, Oliver}}, booktitle = {{2025 IEEE Kiel PowerTech}}, publisher = {{IEEE}}, title = {{{Safe Reinforcement Learning-based Control for a Voltage Source Inverter Operating in an Unbalanced Grid}}}, doi = {{10.1109/powertech59965.2025.11180230}}, year = {{2025}}, } @inproceedings{54355, author = {{Urbaneck, Daniel and Wiegard, Jan and Schafmeister, Frank}}, booktitle = {{PCIM Europe 2024; IEEE International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management}}, location = {{Nuremberg}}, title = {{{Analysis of Inverter Operation Modes of an IGBT-Based ZCS LLC Converter for a 2 kW Automotive On-Board DC-DC}}}, year = {{2024}}, } @inproceedings{54353, author = {{Piepenbrock, Till and Keuck, Lukas and Schachten, Sebastian and Böcker, Joachim and Schafmeister, Frank}}, booktitle = {{PCIM Europe 2024; IEEE International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management}}, location = {{Nuremberg}}, title = {{{Study on Sample Geometries for Ferrite Characterisation in the MHz-Range}}}, year = {{2024}}, } @inproceedings{54354, author = {{Förster, Nikolas and Urbaneck, Daniel and Kohlhepp, Benedikt and Kübrich, Daniel and Schafmeister, Frank}}, booktitle = {{PCIM Europe 2024; IEEE International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management}}, location = {{Nuremberg}}, title = {{{Pitfalls and their Avoidability in the Double-Pulse Test}}}, year = {{2024}}, } @article{53309, author = {{Hölsch, Lukas and Brosch, Anian and Steckel, Richard and Braun, Tristan and Wendel, Sebastian and Böcker, Joachim and Wallscheid, Oliver}}, issn = {{0885-8969}}, journal = {{IEEE Transactions on Energy Conversion}}, keywords = {{Electrical and Electronic Engineering, Energy Engineering and Power Technology}}, pages = {{1--12}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Insights and Challenges of Co-Simulation-Based Optimal Pulse Pattern Evaluation for Electric Drives}}}, doi = {{10.1109/tec.2024.3374962}}, year = {{2024}}, } @inproceedings{54357, author = {{Piepenbrock, Till and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{SPEEDAM 2024; 27th International Symposium on Power Electronics, Electrical Drives, Automation and Motion}}, location = {{Ischia, near Naples, Italy}}, title = {{{FEM Modelling of Dimensional-Resonant Inductors for LLC Converters in MHz Range}}}, doi = {{10.1109/SPEEDAM61530.2024.10609111}}, year = {{2024}}, } @inproceedings{63497, author = {{Förster, Nikolas and Wallscheid, Oliver and Schafmeister, Frank}}, booktitle = {{2024 IEEE Design Methodologies Conference (DMC)}}, keywords = {{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}}, pages = {{1--8}}, title = {{{Dual-Active Bridge Sequential Pareto Optimization for Fast Pre-Design and Final Component Selection}}}, doi = {{10.1109/DMC62632.2024.10812131}}, year = {{2024}}, } @inproceedings{54356, abstract = {{Although there are numerous design and control methodologies for the LLC resonant converter, they often do not consider decentralized control strategies to operate them as isolated DC-DC converters within a cascaded H-bridge. The total output power of all LLC converters must be constant to supply a load such as a wa- ter electrolyzer. However, each individual LLC converter can vary its output power as long as the total output power remains constant. This opens new possibilities in increasing the system efficiency and robustness. Usually, the DC-link voltage of each module capacitor shows a 2nd harmonic voltage ripple. However, the total stored energy in all DC-link capacitors is constant within a grid period for a balanced three-phase system. By controlling each LLC converter’s output power locally to be proportional to the energy stored in its DC-link capacitor, modules with a lower instantaneous DC-link voltage transfer less power to the load than modules with a higher DC-link voltage. As a result, a higher efficiency, voltage gain and lower peak resonant capacitor voltage can be achieved with the same components. The 22.2kW experimental prototype of the LLC converter reaches an efficiency of over 97% at resonance which is similar to the precalculated value.}}, author = {{Unruh, Roland and Böcker, Joachim and Schafmeister, Frank}}, booktitle = {{ECCE Europe 2024; IEEE Energy Conversion Congress & Exposition Europe}}, isbn = {{979-8-3503-6444-6}}, keywords = {{Cascaded H-Bridge, Converter Losses, Decentralized Control, Full-Bridge Converter, LLC Resonant Converter}}, location = {{Darmstadt, Germany}}, publisher = {{IEEE}}, title = {{{Experimentally Verified 22 kW, 40 kHz LLC Resonant Converter Design with new Control for a 1 MW Cascaded H-Bridge Converter}}}, doi = {{https://doi.org/10.1109/ECCEEurope62508.2024.10751954}}, year = {{2024}}, } @inproceedings{58648, author = {{Unruh, Roland and Böcker, Joachim and Schafmeister, Frank}}, booktitle = {{Proceedings of the Energy Conversion Congress & Expo (ECCE Europe)}}, location = {{Darmstadt}}, publisher = {{IEEE}}, title = {{{Experimentally Verified 22 kW, 40 kHz LLC Resonant Converter Design with new Control for a 1 MW Cascaded H-Bridge Converter}}}, doi = {{10.1109/ECCEEurope62508.2024.10751954}}, year = {{2024}}, } @phdthesis{58756, abstract = {{Der Permanentmagnet-Synchronmotor (PMSM) ist aufgrund seiner hohen Leistungs- und Drehmomentdichte bezogen auf Volumen und Gewicht ein häufig verwendeter Traktionsmotor in Automobilanwendungen. Jene Charakteristika werden jedoch maßgeblich durch Temperaturhöchstwerte begrenzt. Hinzu kommt, dass die Temperatur wichtiger Rotorkomponenten nicht wirtschaftlich messbar ist. Temperaturschätzverfahren wie modellbasierte Ansätze sind potentiell in der Lage, das Problem der fehlenden Temperaturinformation zu relativieren, ohne zusätzliche Geräte zu erfordern. Diese Arbeit stellt ein Portfolio von thermischen Modellen aus dem Bereich des maschinellen Lernens zusammen. Die Untersuchung basiert auf einem PMSM-Datensatz, der auf einem Prüfstand aufgezeichnet wurde. Neben dem durchschnittlichen Schätzfehler diktiert die erforderliche Anzahl von Modellparametern zahlreiche Auslegungsentscheidungen. Der gesamte Entwurfsprozess eines Modells aus dem maschinellen Lernen wird beleuchtet und für verschiedene lineare, sowie baumbasierte Modelle; vorschiebende, rekurrente und faltende neuronale Netze als auch für verschiedene hybride Modellierungsansätze durchgeführt. Desweiteren wird der hybride Modellierungsansatz über thermische neuronale Netze besonders hervorgehoben. Sie setzen sich aus neuronalen Netzen und einem thermischen Ersatzschaltbild zusammen und wurden erstmals vom Autor dieser Arbeit veröffentlicht. Schließlich wird ein von Experten entworfenes, datengetriebenes thermisches Netz mit konzentrierten Parametern über verschiedene Algorithmen optimiert und als Stand der Technik herangezogen.}}, author = {{Kirchgässner, Wilhelm}}, publisher = {{LibreCat University}}, title = {{{Data-driven thermal modeling of a permanent magnet synchronous motor with machine learning}}}, doi = {{10.17619/UNIPB/1-2068}}, year = {{2024}}, } @phdthesis{58757, abstract = {{On-bord DC-DC-Konverter sind das Bindeglied zwischen der Traktionsbatterie und der Hilfsbatterie und versorgen wichtige Komponenten des Elektrofahrzeugs. Diese Arbeit adressiert den weiten Spannungsbereich des Wandlers, der eine Folge der variierenden Spannungen der Batterien ist. Als potentielle Topologien werden der LLC Resonanzwandler, der aktiv geklemmte Flusswandler und der isolierte Vollbrücken-Konverter untersucht.Zunächst wird hierbei der LLC untersucht und verschiedene Modulationstechniken zur Abdeckung des weiten Spannungsbereichs gegenübergestellt, um zu zeigen, dass die Frequenzverdoppler-Modulation und die alternierende Phasenverschiebungsmodulation die maximale Temperatur der Halbleiter deutlich senken. Zum Wechsel zwischen Voll- und Halbbrückenmodulation wird eine Modulationstechnik vorgeschlagen, welche den transienten Magnetisierungsfluss um über 70 % respektive des konventionellen Konzept senkt. Für den aktiv geklemmten Flusswandler wird ein verbessertes Modell vorgestellt, das die Blockierspannung sehr genau modelliert. Zudem wird eine Snubber-Schaltung vorgeschlagen, welche die sekundärseitige transiente Blockierspannung deutlich reduziert. Für den isolierten Vollbrücken-Konverter werden hart- und weichschaltende Modulationstechniken analysiert und eine hartschaltende Frequenz-Verdoppler-Modulationstechnik vorgeschlagen, welche die maximale Schaltertemperatur deutlich reduziert und eine Modulationstechnik mit Beschaltung vorgestellt, um zwischen dem Voll- und Halbbrückenmodus zu wechseln. Die zuvor erarbeiteten Konverter werden unter Anwendung einer vorgestellten Designmethodik verglichen und messtechnisch evaluiert.}}, author = {{Rehlaender, Philipp}}, publisher = {{LibreCat University}}, title = {{{Single-stage DC-DC converters for a wide input & output voltage range}}}, doi = {{10.17619/UNIPB/1-2148}}, year = {{2024}}, } @phdthesis{58682, author = {{Brosch, Anian}}, title = {{{Time-optimal control of synchronous machines in the whole modulation range considering current and torque constraints }}}, doi = {{10.17619/UNIPB/1-2064}}, year = {{2024}}, } @article{48059, author = {{Winkel, Fabian and Wallscheid, Oliver and Scholz, Peter and Böcker, Joachim}}, issn = {{2644-1284}}, journal = {{IEEE Open Journal of the Industrial Electronics Society}}, keywords = {{Electrical and Electronic Engineering, Industrial and Manufacturing Engineering, Control and Systems Engineering}}, pages = {{1--14}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Pseudo-Labeling Machine Learning Algorithm for Predictive Maintenance of Relays}}}, doi = {{10.1109/ojies.2023.3323870}}, year = {{2023}}, } @article{48058, author = {{Winkel, Fabian and Deuse-Kleinsteuber, Johannes and Böcker, Joachim}}, issn = {{0018-9529}}, journal = {{IEEE Transactions on Reliability}}, keywords = {{Electrical and Electronic Engineering, Safety, Risk, Reliability and Quality}}, pages = {{1--14}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Run-to-Failure Relay Dataset for Predictive Maintenance Research With Machine Learning}}}, doi = {{10.1109/tr.2023.3255786}}, year = {{2023}}, } @inproceedings{48352, abstract = {{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 = {{Unruh, Roland and Böcker, Joachim and Schafmeister, Frank}}, booktitle = {{2023 25th European Conference on Power Electronics and Applications (EPE'23 ECCE Europe)}}, isbn = {{979-8-3503-1678-0}}, keywords = {{Cascaded H-Bridge, Solid-State Transformer, Capacitor voltage ripple, Zero sequence voltage, Third harmonic injection}}, location = {{Aalborg, Denmark}}, publisher = {{IEEE}}, 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}}, year = {{2023}}, } @inproceedings{48093, author = {{Pena, Mario and Meyer, Michael and Wallscheid, Oliver and Böcker, Joachim}}, booktitle = {{2023 IEEE International Electric Machines and Drives Conference (IEMDC)}}, location = {{San Francisco}}, publisher = {{IEEE}}, title = {{{Fade-Over Strategy for use of Model Predictive Direct Self-Control with Field-Oriented Control}}}, doi = {{10.1109/iemdc55163.2023.10239056}}, year = {{2023}}, } @article{48092, author = {{Pena, Mario and Meyer, Michael and Wallscheid, Oliver and Böcker, Joachim}}, issn = {{0885-8993}}, journal = {{IEEE Transactions on Power Electronics}}, keywords = {{Electrical and Electronic Engineering}}, number = {{10}}, pages = {{12416--12429}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Model Predictive Direct Self-Control for Six-Step Operation of Permanent-Magnet Synchronous Machines}}}, doi = {{10.1109/tpel.2023.3286713}}, volume = {{38}}, year = {{2023}}, } @article{49760, author = {{Jakobeit, Darius and Schenke, Maximilian and Wallscheid, Oliver}}, issn = {{0885-8993}}, journal = {{IEEE Transactions on Power Electronics}}, keywords = {{Electrical and Electronic Engineering}}, number = {{7}}, pages = {{8062--8074}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Meta-Reinforcement-Learning-Based Current Control of Permanent Magnet Synchronous Motor Drives for a Wide Range of Power Classes}}}, doi = {{10.1109/tpel.2023.3256424}}, volume = {{38}}, year = {{2023}}, } @inproceedings{53310, author = {{Gedlu, Emebet Gebeyehu and Wallscheid, Oliver and Böcker, Joachim and Nelles, Oliver}}, booktitle = {{2023 IEEE 14th International Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives (SDEMPED)}}, publisher = {{IEEE}}, title = {{{Online system identification and excitation for thermal monitoring of electric machines using machine learning and model predictive control}}}, doi = {{10.1109/sdemped54949.2023.10271427}}, year = {{2023}}, }