@article{21558, author = {{Brosch, Anian and Hanke, Sören and Wallscheid, Oliver and Böcker, Joachim}}, issn = {{0885-8993}}, journal = {{IEEE Transactions on Power Electronics}}, pages = {{2179--2190}}, title = {{{Data-Driven Recursive Least Squares Estimation for Model Predictive Current Control of Permanent Magnet Synchronous Motors}}}, doi = {{10.1109/tpel.2020.3006779}}, year = {{2020}}, } @inproceedings{29956, author = {{Stille, Karl Stephan Christian and Weber, Daniel and Lange, Jarren and Vogt, Thorsten and Wallscheid, Oliver and Böcker, Joachim}}, booktitle = {{2020 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM)}}, location = {{Sorrent, Italy}}, publisher = {{IEEE}}, title = {{{Emulation of Microgrids for Research and Validation of Control and Operation Strategies}}}, doi = {{10.1109/speedam48782.2020.9161971}}, year = {{2020}}, } @inproceedings{29896, abstract = {{Automotive DC-DC converters linking the traction battery to the auxiliary battery are characterized by the wide input and output voltage ranges resulting from the varying state-of-charge of the traction and auxiliary battery. The wide voltage transfer ratio needs to be covered for the entire load range conventionally requiring two-stage converter architectures. Considering a less complex single-stage solution potentially enabling cost and weight advantages, traditional LLC converters are unsuitable topologies since it results in a too wide operating frequency range. Most alternative topology candidates show comparable difficulties. To overcome this issue, the gain range of the LLC with full-bridge inverter can be extended by operation in half-bridge mode for low voltage transfer ratios. Phase-shift operation is utilized for intermediate gains and low loads. This paper describes a detailed design methodology for the resonant tank. The experimental results with a peak efficiency of 96.5 % and a power density of 2.1 kW/l prove the proposed concept.}}, author = {{Rehlaender, Philipp and Grote, Tobias and Tikhonov, Sergey and Mario, Schröder and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{PCIM Europe digital days 2020}}, location = {{Nürnberg}}, title = {{{A 3,6 kW Single-Stage LLC Converter Operating in Half-Bridge, Full-Bridge and Phase-Shift Mode for Automotive Onboard DC-DC Conversion}}}, year = {{2020}}, } @inproceedings{29898, abstract = {{An onboard DC-DC converter connects the high voltage traction battery to the low voltage auxiliary battery of an EV. It has to provide power across a wide range of input and output voltages. This paper presents the design and evaluation of an economical two-stage converter concept consisting of a first-stage boost converter and a second-stage LLC converter. While for low input voltages, the boost converter can supply the second-stage LLC with the optimum bulk voltage, for high input voltages, the boost converter is turned off and the LLC regulates the output voltage on its own. Whereas this is unproblematic for high output currents, for low loads high switching frequencies become necessary. For this purpose, the LLC needs to be designed for a wide gain range. Traditionally, this is achieved through a small magnetizing inductance resulting in increased conduction losses. If an asymmetric duty cycle operation is used to cover the low gains at low output current, the LLC can be optimized for a better efficiency. A prototype design proves that the asymmetric duty cycle operation is feasible to achieve a wide gain range at a high efficiency whereas the conventional design achieves very poor efficiencies.}}, author = {{Rüschenbaum, Tobias and Rehlaender, Philipp and Ha, Phuong and Grote, Tobias and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{PCIM Europe digital days 2020}}, title = {{{Two-Stage Automotive DC-DC Converter Design with Wide Voltage-Transfer Range Utilizing Asymmetric LLC Operation}}}, year = {{2020}}, } @inproceedings{29874, abstract = {{LLC resonant converters generally employ MOSFETs in the inverter stage, which can be of half-bridge (HB) or full-bridge (FB) type. The generally weak intrinsic (body) diodes of the MOSFETs cause turn-on losses when being forced to hard current commutations finally leading to the components self-destruction when operated constantly in this way. Consequently, zero-voltage switching (ZVS) operation is more or less essential in a silicon (Si) MOSFET-based HB or FB. To ensure ZVS, the LLC is operated in the inductive region, i.e. with lagging resonant current. On the contrary, IGBTs show dominant turn-off losses and therefore are conventionally not applied in LLCs typically requiring high switching frequencies to achieve low output voltages. Yet, if the LLC is intentionally designed for the capacitive region, i. e. operation with leading current, zero-current switching (ZCS) enabling IGBTs in the inverter stage can be ensured. This paper explores in detail the LLC in the capacitive operating region and gives design considerations for a capacitive LLC utilizing both robust and cost-efficient IGBTs for an exemplary 2.2 kW automotive on-board DC-DC converter application. The results of a loss analysis show that the LLC resonant converter can be operated well in the capacitive region. In the given case, significantly lower overall and 30 % lower inverter stage losses are achieved in the thermally relevant worst-case comparison with an inductive LLC based on Si MOSFETs.}}, author = {{Urbaneck, Daniel and Rehlaender, Philipp and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{PCIM Europe digital days 2020}}, location = {{Nürnberg}}, title = {{{LLC Converter Design in Capacitive Operation utilizes ZCS for IGBTs – a Concept Study for a 2.2 kW Automotive DC-DC Stage}}}, year = {{2020}}, } @article{30033, author = {{Stender, Marius and Wallscheid, Oliver and Böcker, Joachim}}, issn = {{0278-0046}}, journal = {{IEEE Transactions on Industrial Electronics}}, keywords = {{Electrical and Electronic Engineering, Control and Systems Engineering}}, number = {{9}}, pages = {{8646--8656}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Comparison of Gray-Box and Black-Box Two-Level Three-Phase Inverter Models for Electrical Drives}}}, doi = {{10.1109/tie.2020.3018060}}, volume = {{68}}, year = {{2020}}, } @inproceedings{30036, author = {{Stender, Marius and Wallscheid, Oliver and Böcker, Joachim}}, booktitle = {{2020 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM)}}, publisher = {{IEEE}}, title = {{{Accurate Torque Estimation for Induction Motors by Utilizing Globally Optimized Flux Observers}}}, doi = {{10.1109/speedam48782.2020.9161955}}, year = {{2020}}, } @inproceedings{29641, author = {{Gedlu, Emebet Gebeyehu and Wallscheid, Oliver and Böcker, Joachim}}, booktitle = {{The 10th International Conference on Power Electronics, Machines and Drives (PEMD 2020)}}, pages = {{937–942}}, title = {{{Permanent magnet synchronous machine temperature estimation using low-order lumped-parameter thermal network with extended iron loss model}}}, volume = {{2020}}, year = {{2020}}, } @inproceedings{30339, author = {{Ahmmad, Mohsin Ejaz and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{Proc. IEEE International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management (PCIM digital days)}}, location = {{Nuremberg, Germany}}, publisher = {{IEEE}}, title = {{{Practical Implementation and Verification of Simple-to-Implement Digital Current Observer for Half-Bridge Topologies}}}, year = {{2020}}, } @article{29642, author = {{Hanke, Sören and Wallscheid, Oliver and Böcker, Joachim}}, journal = {{arXiv preprint arXiv:2003.06268}}, title = {{{Data Set Description: Identifying the Physics Behind an Electric Motor–Data-Driven Learning of the Electrical Behavior (Part II)}}}, year = {{2020}}, } @article{29640, author = {{Kirchgässner, Wilhelm and Wallscheid, Oliver and Böcker, Joachim}}, journal = {{arXiv preprint arXiv:2001.06246}}, title = {{{Data-Driven Permanent Magnet Temperature Estimation in Synchronous Motors with Supervised Machine Learning}}}, year = {{2020}}, } @techreport{30034, author = {{Stender, Marius and Wallscheid, Oliver and Böcker, Joachim}}, title = {{{Data Set Description: Three-Phase IGBT Two-Level Inverter for Electrical Drives}}}, doi = {{10.13140/RG.2.2.23335.37280}}, year = {{2020}}, } @inproceedings{29940, abstract = {{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 = {{Unruh, Roland and Schafmeister, Frank and Fröhleke, Norbert and Böcker, Joachim}}, booktitle = {{PCIM Europe digital days 2020; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management}}, isbn = {{978-3-8007-5245-4}}, keywords = {{Cascaded H-Bridge, Solid-State Transformer, Capacitor voltage ripple, Zero sequence voltage, Full-Bridge}}, location = {{Germany}}, publisher = {{VDE}}, title = {{{1-MW Full-Bridge MMC for High-Current Low-Voltage (100V-400V) DC-Applications}}}, year = {{2020}}, } @inproceedings{30001, abstract = {{Heat dissipation is a limiting factor in the performance of many power electronic components. Especially in the TO-263-7 package, which is used for several SiC-MOSFETs, the heat transfer must take place through the cross section of the printed circuit board (PCB) to the heatsink at the bottom side. Most commonly, thermal vias are used to form this path in a perpendicular direction through all PCB-layers. In a given soft- and hard switched example applications with the use of C3M0065090J SiC-MOSFETs, this conventional approach limited the component’s maximum heat dissipation to approx. 13 W. A recent alternative approach are massive copper blocks (”pedestals”) being integrated in PCBs and reaching from their top- to the bottom-side in relevant footprint areas under SMD-housed power semiconductors. Pedestals allowing to increase the heat dissipation in the given case to even 36 W. This step is achieved due to the clearly superior heat spreading capability of that massive thermal connection between SiC-MOSFET and heatsink. For the hard switched example application the number of switch-elements can be halved to one, by using the pedestal instead of thermal vias. Independently of optimizing the heat transfer path, the up-front avoidance of losses helps to stay within existing heat dissipation limits, of course. The dominant conduction losses of the mentioned soft-switched example application could be halved by changing to SiC-MOSFET types with significant lowered RDSon. By using pedestals and changing to SiC-MOSFETs with lowered RDSon, the number of switch-elements can also be halved for the soft switched application.}}, author = {{Strothmann, Benjamin and Piepenbrock, Till and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{PCIM Europe digital days 2020; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management}}, pages = {{1--7}}, title = {{{Heat dissipation strategies for silicon carbide power SMDs and their use in different applications}}}, year = {{2020}}, } @inproceedings{29880, abstract = {{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 = {{Unruh, Roland and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{2020 IEEE 21st Workshop on Control and Modeling for Power Electronics (COMPEL)}}, keywords = {{Full-bridge, High voltage power converters, LLC resonant converter, Multilevel converters, ZVS Converters}}, publisher = {{IEEE}}, title = {{{11kW, 70kHz LLC Converter Design with Adaptive Input Voltage for 98% Efficiency in an MMC}}}, doi = {{10.1109/compel49091.2020.9265771}}, year = {{2020}}, } @inproceedings{29885, author = {{Joy, Meryl Teresa and Böcker, Joachim}}, booktitle = {{2018 IEEE International Conference on Power Electronics, Drives and Energy Systems (PEDES)}}, location = {{Chennai, India}}, publisher = {{IEEE}}, title = {{{Speed Estimation in Induction Machines at all Speed Ranges Using Sensing Windings}}}, doi = {{10.1109/pedes.2018.8707494}}, year = {{2019}}, } @inproceedings{21247, author = {{Kirchgässner, Wilhelm and Wallscheid, Oliver and Böcker, Joachim}}, booktitle = {{2019 IEEE 28th International Symposium on Industrial Electronics (ISIE)}}, isbn = {{9781728136660}}, title = {{{Empirical Evaluation of Exponentially Weighted Moving Averages for Simple Linear Thermal Modeling of Permanent Magnet Synchronous Machines}}}, doi = {{10.1109/isie.2019.8781195}}, year = {{2019}}, } @inproceedings{21249, author = {{Kirchgässner, Wilhelm and Wallscheid, Oliver and Böcker, Joachim}}, booktitle = {{2019 IEEE International Electric Machines & Drives Conference (IEMDC)}}, isbn = {{9781538693506}}, title = {{{Deep Residual Convolutional and Recurrent Neural Networks for Temperature Estimation in Permanent Magnet Synchronous Motors}}}, doi = {{10.1109/iemdc.2019.8785109}}, year = {{2019}}, } @inproceedings{29999, abstract = {{For future Vehicle-to-Grid (V2G) applications, the six-switch full-bridge is often used as AC-DC front-end converter of a three-phase EV-charger. In many publications, the common mode (CM) noise is not taken into account. However, this must not be neglected considering the large effective capacitance, of up to 3 muF, as allowed by new standards. In this paper, different modulation techniques are investigated, related to their CM-noise. Based on electric circuit simulations, CM-filters are estimated, and the CM-currents are investigated. Accordingly, the conventional six-switch full-bridge is practically difficult to use in non-isolated chargers, because the resulting CM-currents and/or the required EMI-filter become too large, even if CM-Voltage optimized modulation techniques are used.}}, author = {{Strothmann, Benjamin and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{PCIM Europe 2019; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management}}, pages = {{1--7}}, title = {{{Common Mode Analysis of Non-Isolated Three-Phase EV-Charger for Bi-Directional Vehicle-to-Grid Operation}}}, year = {{2019}}, } @inproceedings{30002, abstract = {{Utilisation of SiC semiconductors' fast switching speeds and high switching frequencies as a consequent are often in discussion. But which switching frequency is really optimal in terms of converter volume, losses and costs? Based on the example of a buck converter, this question is investigated, and a tool for loss calculation and design is described in this paper. A Pareto optimization of the converter is performed where the switching frequency is one of several design parameters. The buck converter can be realized by multiple rails interleaved, and several switches can be placed in parallel. Considered converter modes are continuous conduction mode, that allows hard-switching, ZVS, and incomplete ZVS depending on the switching frequency. Based on Pareto optimizations, a design is selected, and a laboratory sample of 5.5 kW for application in an EV battery charger is built up. Efficiencies of 99.5 % are achieved with switching frequencies of around 100 kHz.}}, author = {{Strothmann, Benjamin and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{2019 IEEE Applied Power Electronics Conference and Exposition (APEC)}}, publisher = {{IEEE}}, title = {{{Pareto Design and Switching Frequencies for SiC MOSFETs Applied in an 11 kW Buck Converter for EV-Charging}}}, doi = {{10.1109/apec.2019.8721850}}, year = {{2019}}, }