TY - CHAP A1 - Mai, Annette A1 - Wagner, Bernhard A1 - Streit, Fabian T1 - Elimination of Current Harmonics in Electrical Machines with Iterative Learning Control N2 - The magnitude of current harmonics depends on the design of an electrical machine. By suppressing these harmonics noise can be reduced and efficiency improved. Iterative Learning Control (ILC) has proven effective in reducing harmonics. One of the challenges of working with ILC is operation at varying speeds. Variable speeds are particularly important for applications like automotive drives. The ILC period length changes during the learning process at varying speeds. Due to fixed sample rates, the number of values processed by the ILC varies with motor speed.This paper proposes a method to solve this problem and uses ILC at varying speeds. The ILC used to eliminate the harmonics is based on the inverse system. The usage of a two-dimensional memory array is proposed. This data structure holds rows for specific speeds between which interpolation is performed, enabling the elimination of errors which are periodically cyclic to one electrical rotation. This includes the reduction of the motor current harmonics. To verify the presented method a permanent magnet synchronous motor with distinctive 5th and 7th harmonics is used. In real-time implementations, limitations of memory and computational capacity occur. KW - Iterative Learning Control, Repetitive Control, Current Harmonics, PMSM, Motor Control Y1 - 2020 U6 - https://doi.org/10.1109/EDPC51184.2020.9388177 VL - 2020 ER - TY - CHAP A1 - Liegmann, Eyke A1 - Schindler, Tobias A1 - Karamanakos, Petros A1 - Dietz, Armin A1 - Kennel, Ralph T1 - UltraZohm — An Open-Source Rapid Control Prototyping Platform for Power Electronic Systems T2 - 2021 International Aegean Conference on Electrical Machines and Power Electronics (ACEMP) & 2021 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM) N2 - 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. Y1 - 2021 U6 - https://doi.org/10.1109/optim-acemp50812.2021.9590016 SN - 1842-0133 PB - IEEE ER - TY - CHAP A1 - Gerstner, Michael A1 - Maerz, Martin A1 - Dietz, Armin T1 - Reconfigurable Transformer for Wide Input Voltage Range DC/DC Converters T2 - 2020 IEEE 9th International Power Electronics and Motion Control Conference (IPEMC2020-ECCE Asia) N2 - 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. KW - DC/DC converter ; efficiency ; tapped transformer ; wide input voltage range Y1 - 2020 U6 - https://doi.org/10.1109/ipemc-ecceasia48364.2020.9367869 PB - IEEE ER - TY - CHAP A1 - Dietz, Armin A1 - di Tommaso, A. O. A1 - Miceli, R. A1 - Nevoloso, C. A1 - Schettino, G. T1 - Enhanced Modelling for Extended Performance Analysis of Interior Permanent Magnet Synchronous Machine Drive fed with Cascaded H-Bridges Multilevel Inverter T2 - 2021 Sixteenth International Conference on Ecological Vehicles and Renewable Energies (EVER) N2 - This paper presents a comparative simulation analysis of an Interior Permanent Magnet Synchronous Machine (IPMSM) performance once fed by a traditional three-phase two-level inverter and then using a three-phase five-level Cascaded H-Bridges Multilevel Inverter (CHBMI). For this purpose, an enhanced mathematical model of the IPMSM, that take into account simultaneously saturation, cross-coupling, spatial harmonics and iron loss effects, has been employed. Furthermore, two different PWM modulation strategies have been considered. The study was conducted for several working conditions, evaluating the impact of CHBMI adoption on the IPMSM performance in terms of improved efficiency and torque ripple reduction. Y1 - 2021 U6 - https://doi.org/10.1109/ever52347.2021.9456635 PB - IEEE ER - TY - CHAP A1 - Hoerner, Michael A1 - Wendel, Sebastian A1 - Dietz, Armin A1 - Karamanakos, Petros A1 - Kennel, Ralph T1 - Variable Switching Point Predictive Current Control for Multi-Phase Permanent Magnet Synchronous Drives T2 - 2021 IEEE International Conference on Predictive Control of Electrical Drives and Power Electronics (PRECEDE) N2 - 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). KW - Model predictive control, FCS-MPC, VSP2CC, VV-MPC, multi-phase, PMS Y1 - 2022 U6 - https://doi.org/10.1109/precede51386.2021.9680920 PB - IEEE ER - TY - CHAP A1 - Rabenstein, L. A1 - Schmidt, M. A1 - Dietz, A. A1 - Parspour, N. T1 - Design, Construction and Measurement of a Laminated Transverse Flux Machine T2 - 2022 International Conference on Electrical Machines (ICEM) N2 - This paper presents the design, construction and measurements on a transverse flux machine. The lamination concept is designed for easy fabrication and low iron losses. For a good flux guidance and a high magnetic field, electrical sheet is used for the soft magnetic circuit. The design of the machine is performed with a fast semi-analytical calculation and validated by 3D finite element analysis. The calculated quantities are compared with measurements on a prototype. Despite certain deviations, the measurements show good agreement with the calculations for the induced voltage and torque. In terms of efficiency, however, the measurement deviates significantly from the simulation. This is due to the iron losses being calculated much too small, which is evident from the separation of the measured losses. KW - asymmetric phase shift, finite element analy- ses, passive rotor, prototype measurements, semi-analytical cal- culation, separation of losses, synchronous machine, transverse flux machine Y1 - 2022 U6 - https://doi.org/10.1109/icem51905.2022.9910771 SN - 2381-4802 PB - IEEE ER - TY - CHAP A1 - Wendel, Sebastian A1 - Karamanakos, Petros A1 - Dietz, Armin A1 - Kennel, Ralph T1 - Flux Linkage-Based Model Predictive Current Control for Nonlinear PMSM Drives T2 - IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society N2 - In this paper, a flux linkage-based direct model predictive current control approach is presented for small permanent magnet synchronous motor (PMSM) drives. The method aims to minimize the current ripples at steady state by deciding on the optimal switching instant, while exhibiting fast dynamic behavior during transients. To this end, the future trajectory of the stator current is not computed based on the machine inductances or inductance look-up tables, but on the changes of the magnetic flux linkage by utilizing flux linkage maps. As shown, the proposed method can be particularly advantageous for electric drives with a noticeable nonlinearity in terms of saturation and/or cross-coupling effects since it allows for a significantly increased prediction accuracy, which leads to an improved steady-state performance as indicated by the reduced current distortions. KW - Couplings ; Switches; Predictive models ; Mathematical model ; Rotors ; Real-time systems ; Prediction algorithmso Y1 - 2022 U6 - https://doi.org/10.1109/iecon43393.2020.9254484 PB - IEEE ER - TY - CHAP A1 - Schindler, Tobias A1 - Dietz, Armin T1 - Real-Time Inference of Neural Networks on FPGAs for Motor Control Applications T2 - 2020 10th International Electric Drives Production Conference (EDPC) N2 - 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. Y1 - 2020 U6 - https://doi.org/10.1109/edpc51184.2020.9388185 SP - 1 EP - 6 PB - IEEE ER - TY - CHAP A1 - Gerstner, Michael A1 - Maerz, Martin A1 - Dietz, Armin T1 - Design of a Wide Input Voltage Range Current-Fed DC/DC Converter Within a Reduced Duty-Cycle Range T2 - 2020 22nd European Conference on Power Electronics and Applications (EPE'20 ECCE Europe) N2 - A design of a current-fed push-pull converter for wide input voltage ranges within a reduced duty-cycle range is presented. Based on the converter conversion ratios of three different clamping configurations, the potential of the input clamping is shown analytical, simulative and by measurements. A differentiation is made between the four possible operating modes, which can be distinguished in the control of the semiconductors and the magnetomotive force in the reactor. By optimizing the turn ratios of both transformers, the wide input voltage range capability of the input clamped current-fed push-pull converter was improved, which has been proved by measurements on a real prototype. KW - DC power supply ; Design ; Converter circuit ; Measurement ; Power Supply Y1 - 2020 U6 - https://doi.org/10.23919/epe20ecceeurope43536.2020.9215825 PB - IEEE ER - TY - CHAP A1 - Gerstner, Michael A1 - Maerz, Martin A1 - Dietz, Armin T1 - Review-based Selection Recommendation for Galvanically Isolated DC/DC Converters Designed For a Wide Input Voltage Range T2 - 2021 IEEE 19th International Power Electronics and Motion Control Conference (PEMC) N2 - Depending on the application range, there are various recommendations in the literature which converter topology should be used. These are mostly based on experience or more or less deeper considerations. For DC/DC converters, which are operated over a wide input voltage range, such recommendations rarely exist. Therefore, this contribution shows the evolution of two input voltage dependent selection matrices, which should facilitate the selection of future topologies based on known publications and basic considerations. The focus here lies on converters for λ = V i_max /V i_min ≥ 3 with galvanic isolation. First, the data set is introduced, where a distinction is made between flyback converters, forward converters and other 1stage or 2stage converters before the evolution of the novel input voltage dependent matrices is carried out. These two matrices support the selection of a suitable topology and whether the energy transfer should be done by one or two stages. Y1 - 2021 U6 - https://doi.org/10.1109/pemc48073.2021.9432537 SP - 167 EP - 172 PB - IEEE ER -