@inproceedings{LiegmannSchindlerKaramanakosetal.2021, author = {Liegmann, Eyke and Schindler, Tobias and Karamanakos, Petros and Dietz, Armin and Kennel, Ralph}, title = {UltraZohm — An Open-Source Rapid Control Prototyping Platform for Power Electronic Systems}, series = {2021 International Aegean Conference on Electrical Machines and Power Electronics (ACEMP) \& 2021 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM)}, booktitle = {2021 International Aegean Conference on Electrical Machines and Power Electronics (ACEMP) \& 2021 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM)}, publisher = {IEEE}, issn = {1842-0133}, doi = {10.1109/optim-acemp50812.2021.9590016}, pages = {6}, year = {2021}, abstract = {This paper presents two rapid control prototyping (RCP) use cases facilitated by the open-source platform UltraZohm. The openly available UltraZohm development frame- work eases the transition from simulation to the test bench. The framework offers the integration of automatic code generation for field-programmable gate arrays (FPGAs), either by using Simulink models based on the HDL Coder, or by synthesizing C++ code into VHDL via the Vivado high-level synthesis tool. The first use case focuses on the implementation details of an on-chip controller-in-the-loop setup, where a permanent magnetsynchronous machine is emulated in the FPGA with a sampling frequency of 2 MHz. The second use case presents an efficient real-time implemen-tation of the sphere decoding algorithm employed to solve the long-horizon finite control set model predictive control problem for a three-level neutral point clamped inverter driving an induction machine. Experimental results based on a small-scale prototype confirm that the algorithm can be executed in real time on the FPGA, with an execution time of a few tens of microseconds. Both use cases highlight the benefits of using a high-performance RCP platform for research in power electronics and their control.}, language = {en} } @inproceedings{SchierEppleMaaouietal.2020, author = {Schier, Michael and Epple, Fabius and Maaoui, Aicha and Schwellinger, Martin and Weber, Michael and Dietz, Armin and Zimmermann, Rolf}, title = {Development of a Two In One Motor System as a new Vehicle Energy Concept for Next Generation Car}, series = {2020 Fifteenth International Conference on Ecological Vehicles and Renewable Energies (EVER)}, booktitle = {2020 Fifteenth International Conference on Ecological Vehicles and Renewable Energies (EVER)}, publisher = {IEEE}, doi = {10.1109/ever48776.2020.9243148}, pages = {12}, year = {2020}, language = {en} } @inproceedings{RegnetSchaeufeleDietzetal.2023, author = {Regnet, Martin and Sch{\"a}ufele, Thomas and Dietz, Armin and L{\"o}hlein, Bernd}, title = {Temperature influence on core losses and magnetization demand of electrical steel sheets using adapted Epstein frame and ring probe}, series = {2023 13th International Electric Drives Production Conference (EDPC)}, booktitle = {2023 13th International Electric Drives Production Conference (EDPC)}, publisher = {IEEE}, isbn = {979-8-3503-7049-2}, doi = {10.1109/edpc60603.2023.10372149}, pages = {7}, year = {2023}, abstract = {In this paper, the influence of temperatures up to 250 °C on core losses and magnetization demand of electrical steel sheets is illustrated. Therefore, measurements are made using an adopted high-temperature Epstein frame and a stator core as a ring probe. Three different electrical steel sheet grades, M330-50A, M530-50A and NO20-15, and a stator core are tested. Magnetic property measurements are performed at various frequencies from DC to 1.2 kHz with a defined sinusoidal waveform of magnetic polarization. This covers a wide range of electric motor applications from industrial drives to electric vehicle drives. With increasing temperature, magnetization demand rises significantly in medium polarization range. For specific core losses, a loss separation is performed using the Jordan approach, separating specific hysteresis and specific eddy current losses to determine the temperature influence on each loss component. The temperature behavior of the specific electrical resistivity of electrical steel sheets is measured and used to calculate the physical specific eddy current losses. After separation, specific hysteresis losses also show a significant temperature influence.}, language = {en} } @inproceedings{SchmidtWilflingDietzetal.2023, author = {Schmidt, Michael and Wilfling, Timo and Dietz, Armin and Parspour, Nejila}, title = {An overview of design and calculation of a synchronous-reluctance machine}, series = {2023 13th International Electric Drives Production Conference (EDPC)}, booktitle = {2023 13th International Electric Drives Production Conference (EDPC)}, publisher = {IEEE}, isbn = {979-8-3503-7049-2}, doi = {10.1109/edpc60603.2023.10372169}, pages = {8}, year = {2023}, abstract = {Because of the absence of rare earth magnets, the reluctance synchronous machine has a more favourable sustainability balance compared to the permanent magnet synchronous machine with NdFeB magnets. Additional advantages include the absence of copper in the rotor and the ease of manufacture of the non modified rotor. A clear disadvantage of the reluctance synchronous machine is the relatively high torque ripple if no measures such as skewing are taken. Therefore, the machine is mainly used in applications such as fans where the torque ripple is not critical for the operation. The paper makes a contribution to addressing the problem of torque pulsation. For the reduction of torque harmonics, the usage of various rotor designs as well as asymmetric rotor geometry are presented. In addition, the aspect of torque harmonics, which is predicted by the finite element analysis is discussed and possibilities of torque ripple reduction for further investigations are shown. The description of a reluctance network of the machine is addressed with a semi-analytical approach for this purpose. Finally, the results of the preliminary calculation are validated by finite element analysis (FEA) and the quantities are verified with measurements on a device under test. The deviations between the methods are shown and discussed.}, language = {en} } @inproceedings{GerstnerMaerzDietz2020, author = {Gerstner, Michael and Maerz, Martin and Dietz, Armin}, title = {Reconfigurable Transformer for Wide Input Voltage Range DC/DC Converters}, series = {2020 IEEE 9th International Power Electronics and Motion Control Conference (IPEMC2020-ECCE Asia)}, booktitle = {2020 IEEE 9th International Power Electronics and Motion Control Conference (IPEMC2020-ECCE Asia)}, publisher = {IEEE}, doi = {10.1109/ipemc-ecceasia48364.2020.9367869}, year = {2020}, abstract = {A transformer with variable primary windings for wide input voltage range DC/DC converters is presented. This transformer structure allows three states of the primary winding to be converted by only two individual windings. Based on the evaluations of a two-switch flyback converter, the potential of DC/DC converters with variable structures, the implementation of such a transformer and the advantages and disadvantages are shown and discussed. Real measurement results demonstrate the noticeable increase in efficiency and the reduction in component stress, having a positive influence on the operation of the converter and the component selection during the design process.}, language = {en} } @inproceedings{HoernerWendelDietzetal.2021, author = {Hoerner, Michael and Wendel, Sebastian and Dietz, Armin and Karamanakos, Petros and Kennel, Ralph}, title = {Variable Switching Point Predictive Current Control for Multi-Phase Permanent Magnet Synchronous Drives}, series = {2021 IEEE International Conference on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)}, booktitle = {2021 IEEE International Conference on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)}, publisher = {IEEE}, doi = {10.1109/precede51386.2021.9680920}, pages = {6}, year = {2021}, abstract = {Finite control set model predictive control (FCS-MPC) is a promising method for the control of multi-phase machines, due to its capability to directly account for nonlinearities and multiple controlled variables. To overcome the drawback of high current ripples and excitation of harmonic currents in the so-called xy-subsystem, several methods have been proposed in the literature so far. This paper proposes an MPC-based method that achieves high granularity of switching by not only switching at the discrete time steps, but also within the sampling interval. In doing so, the discussed algorithm, referred to as variable switching point current control (VSP 2 CC), produces low current distortions, while still keeping the advantages of conventional FCS-MPC, such as fast dynamic behavior during transients. To highlight the above, VSP 2 CC is applied to a six-phase permanent magnet synchronous machine (PMSM) and compared with conventional FCS-MPC and MPC that employs virtual voltage vectors (VV-MPC).}, language = {en} } @inproceedings{WilflingSchmidtDietzetal.2023, author = {Wilfling, Timo and Schmidt, Michael and Dietz, Armin and M{\"o}ckel, Andreas}, title = {Segmented exterior-rotor PMSM for increased torque density}, series = {2023 13th International Electric Drives Production Conference (EDPC)}, booktitle = {2023 13th International Electric Drives Production Conference (EDPC)}, publisher = {IEEE}, isbn = {979-8-3503-7049-2}, doi = {10.1109/edpc60603.2023.10372162}, pages = {8}, year = {2023}, abstract = {Embedded permanent magnets are widely used for electrical machines with interior-rotor. This provides better protection of the magnets and enables the use of an additional reluctance torque for torque density improvements. For external rotors, the use of surface-mounted permanent magnets is common. The following paper analyses the application of inserted magnets at exterior-rotors with segmentation to achieve an increase in torque density.High pole electrical machines are often designed with a fractional-slot concentrated winding which leads to field harmonics. Therefore, an analytical method for qualitative comparison of different winding configurations for using reluctance torque with consideration of stator field harmonics is applied. Besides rotor saliency, the magnetic flux concentration is a positive effect of interior permanent magnets. Here, the flux leakage along mechanical necessary iron bridges is crucial. With the segmented rotor geometry, these iron bridges can be avoided for interior placed magnets. This allows a flux concentration for electrical machines with a high number of pole-pairs. The paper presents a simplified geometry-based approach to describe these improvements. The method is validated with a finite element analysis (FEA) and a prototype with a segmented rotor is built.}, language = {en} } @inproceedings{SchindlerDietz2020, author = {Schindler, Tobias and Dietz, Armin}, title = {Real-Time Inference of Neural Networks on FPGAs for Motor Control Applications}, series = {2020 10th International Electric Drives Production Conference (EDPC)}, booktitle = {2020 10th International Electric Drives Production Conference (EDPC)}, publisher = {IEEE}, doi = {10.1109/edpc51184.2020.9388185}, pages = {1 -- 6}, year = {2020}, abstract = {Machine learning algorithms are increasingly used in industrial applications for a multitude of use-cases. However, using them in control tasks is a challenge due to real-time requirements and limited resources. In this paper, an implementation scheme for real-time inference of multilayer perceptron (MLP) neural networks on FPGAs is proposed. Design constraints for using MLPs in reinforcement learning agents for motor control applications are derived and accounted for in the implementation. Two MLP architectures are evaluated on an FPGA, and the timing and resource-usage data are reported. The real-time capability of the implementation for motor control applications is investigated for standard control frequencies. It is shown by experimental validation that real-time interference with an area-efficient implementation for motor control applications is achievable. Therefore, the proposed implementation scheme can be applied to deep reinforcement learning controllers with hard real-time requirements.}, language = {en} }