TY - THES A1 - Wendt, Thilo T1 - Inference and Training of a Multilayer Perceptron in a Deep Reinforcement Learning Context on a FPGA N2 - This thesis addresses the design and verification of a multilayer perceptron (MLP) and the corresponding optimization algorithm, the batch gradient descent (BGD), on a FPGA using high level synthesis (HLS) for Xilinx devices. The solutions developed in this project are used in a reinforcement learning environment for the control of power electronic systems. The thesis briefly presents the principle of reinforcement learning, a mathematical description of the MLP and the BGD as well as programming techniques for HLS. The structure of the solutions and performance examinations are presented in the results part of the thesis. The project delivers functionally verified solutions for the execution on a FPGA. The solutions are able to process a three layer MLP with 16 inputs and outputs and 128 neurons in the hidden layer in 2,361 clock cycles at 100 MHz clock frequency which results in a runtime of 23.6 µs. The corresponding BGD for one training example features a minimum runtime of 13,141 clock cycles or 1,314 µs. However, performance is expected to further improve after resolving several issues described in the thesis. KW - FPGA KW - Artificial Neural Network KW - Batch Gradient Descent KW - High Level Synthesis KW - Neuronales Netz KW - Logiksynthese KW - Field programmable gate array Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:92-opus4-8521 ER - TY - CHAP A1 - Zocher, Markus A1 - Starost, Veit A1 - Grass, Norbert A1 - Schmidt, Michael A1 - Wilfling, Timo T1 - High Bandwidth Integrator for Differential, PCB Integrated Rogowski Coils T2 - 2023 International Conference on Electrical Drives and Power Electronics (EDPE) N2 - This paper provides an accurate and high-bandwidth current measurement method, using a differential, PCB integrated Rogowski coil. This measurement is ideal for switching characterization of wide-bandgap semiconductors, which are progressively improving switching speeds of power electronic circuits and require a PCB design with low parasitic inductance. A design workflow for system integration of a differential Rogowski coil, including the necessary signal processing circuits onto a printed circuit board is provided. Different parasitic effects have been analyzed, and an amplifier topology for high bandwidth and superior Common Mode rejection is presented. The calculations are verified by simulation and measurements. KW - ogowski, current measurement, differential coils, PCB, high bandwidth, common mode rejection, WBG Y1 - 2023 U6 - https://doi.org/10.1109/EDPE58625.2023.10274019 SP - 1 EP - 8 PB - IEEE 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 - TY - JOUR A1 - Wendel, Sebastian A1 - Karamanakos, Petros A1 - Gebhardt, Philipp A1 - Dietz, Armin A1 - Kennel, Ralph T1 - Flux Linkage-Based Direct Model Predictive Current Control for Synchronous Machines JF - IEEE Transactions on Power Electronics N2 - This article presents a flux linkage-based direct model predictive current control approach that achieves favorable performance both during steady-state and transient operation. The former is achieved by computing the optimal time instants at which a new switch position is applied to the converter. To this end, the future current behavior is not computed based on the machine inductances or inductance look-up tables; instead, flux linkage maps are utilized to predict the trajectory of the magnetic flux linkage, and subsequently of the current. This is advantageous for electric drives with noticeable magnetic nonlinearity in terms of saturation and/or cross-coupling effects. Hence, by using flux linkage maps in the prediction process, the evolution of the stator current can be calculated more accurately, enabling the controller to make better switching decisions. Moreover, the discussed predictive controller exhibits excellent dynamic performance owing to its direct control nature, i.e., the control and modulation tasks are performed in one computational stage rendering a dedicated modulation stage redundant. Three different drive systems based on permanent magnet synchronous motors are examined to demonstrate the effectiveness of the presented control approach. Y1 - 2021 U6 - https://doi.org/10.1109/tpel.2021.3083657 SN - 0885-8993 VL - 36 IS - 12 SP - 14237 EP - 14256 PB - Institute of Electrical and Electronics Engineers (IEEE) ER - TY - JOUR A1 - Dietz, Armin A1 - Di Tommaso, Antonino Oscar A1 - Marignetti, Fabrizio A1 - Miceli, Rosario A1 - Nevoloso, Claudio T1 - Enhanced Flexible Algorithm for the Optimization of Slot Filling Factors in Electrical Machines JF - Energies N2 - The continuous development in the field of industrial automation and electric mobility has led to the need for more efficient electrical machines with a high power density. The improvement of electrical machines’ slot filling factors is one of the measures to satisfy these requirements. In recent years, this topic has aroused greater interest in the industrial sector, since the evolution of the winding technological manufacturing processes allows an economically sustainable realization of ordered winding arrangements, rather than random ones. Moreover, the manufacture of electrical machines’ windings must be preceded by an accurate design phase in which it is possible to evaluate the maximum slot filling factor obtainable for a given wire shape and for its dimensions. For this purpose, this paper presents an algorithmic approach for the evaluation of maximum slot filling factors in electrical machines under an ideal geometric premise. In particular, this algorithm has a greater degree of flexibility with respect to the algorithm approaches found in the literature, since the study has been extended to round, rectangular and hexagonal wire sections. Furthermore, the slot filling factor calculation was carried out both for standard and non-standard slots. The algorithmic approach proposed can be considered as an additional useful tool for the fast design of electrical machine windings. KW - electrical motors; sot filling factor; optimization algorithm; windings; magnetic wire; filling factor optimization Y1 - 2020 U6 - https://doi.org/10.3390/en13051041 SN - 1996-1073 VL - 13 IS - 5 PB - MDPI AG ER - TY - CHAP A1 - Dietz, Armin A1 - Caruso, M. A1 - Di Tommaso, A. O. A1 - Miceli, R. A1 - Nevoloso, C. T1 - Enhanced Mathematical Modelling of Interior Permanent Magnet Synchronous Machine Considering Saturation, Cross-Coupling and Spatial Harmonics effects T2 - 2020 Fifteenth International Conference on Ecological Vehicles and Renewable Energies (EVER) N2 - The Interior Permanent Magnet Synchronous machine (IPMSM) conventional mathematical model is generally employed to investigate and simulate the IPMSM control and drive system behaviour. However, magnetic nonlinearities and spatial harmonics have a substantial influence on the IPMSM electromagnetic behaviour and performances. In order to simulate the IPMSM real electromagnetic behaviour, this paper describes an enhanced mathematical model that takes into account the saturation, cross-coupling and spatial harmonics effects. This model has been implemented in Matlab®/Simulink environment where the electric and magnetic parameters are derived from FEA investigations and implemented by the use of lookup tables. The high fidelity of the proposed IPMSM Simulink model is validated by the results of the FEA investigations carried out. KW - Finite Element Analysis (FEA); Interior Permanent Magnet Synchronous Machine (IPMSM); saturation; cross- coupling; spatial harmonics Y1 - 2020 U6 - https://doi.org/10.1109/ever48776.2020.9243003 PB - IEEE ER - TY - CHAP A1 - Rabenstein, Lukas A1 - Dietz, Armin A1 - Parspour, Nejila T1 - Design Concept of a Wound Field Transverse Flux Machine using Soft Magnetic Composite Claw-Poles T2 - 2020 10th International Electric Drives Production Conference (EDPC) N2 - This paper presents the machine concept of a wound field transverse flux machine (WFTFM). In contrast to permanent magnet transverse flux machines (PMTFM), here the magneto motive force (mmf) of the rotor is generated by a current. The magnetic circuit of the WFTFM is made of soft magnetic composite (SMC) and is designed as claw-poles. Thus the magnetic circuit consists of only a few components. Together with the simple ring coils in stator and rotor, the WFTFM offers advantages in the production of electrical machines. The basic structure of the machine and a first design is described here. The results generated by numerical three-dimensional finite element analysis (FEA) are compared with those of conventional machines. Y1 - 2021 U6 - https://doi.org/10.1109/edpc51184.2020.9388176 PB - IEEE ER - TY - CHAP A1 - Schier, Michael A1 - Epple, Fabius A1 - Maaoui, Aicha A1 - Schwellinger, Martin A1 - Weber, Michael A1 - Dietz, Armin A1 - Zimmermann, Rolf T1 - Development of a Two In One Motor System as a new Vehicle Energy Concept for Next Generation Car T2 - 2020 Fifteenth International Conference on Ecological Vehicles and Renewable Energies (EVER) KW - Air conditioning;Electric potential;Biological system modeling;Production;Automobiles;Next generation networking;Engines Y1 - 2020 U6 - https://doi.org/10.1109/ever48776.2020.9243148 PB - IEEE ER - TY - CHAP A1 - Rabenstein, L. A1 - Dietz, A. A1 - Kremser, A. A1 - Parspour, N. T1 - Semi-Analytical Calculation of a Laminated Transverse Flux Machine T2 - 2020 International Conference on Electrical Machines (ICEM) N2 - n this paper a semi-analytical calculation of a transverse flux machine is presented. First the design of the machine is explained, then the semi-analytical calculation, which is finally compared with a numerical 3D finite element analysis (FEA). The semi-analytical approach is based on a magnetic equivalent circuit, which is solved by nodal analysis and the Broyden-Method. The air gap of the machine is transformed into the magnetic equivalent circuit by conformal mapping using the Schwarz-Christoffel transformation. The comparison to numerical simulation shows that the approach gives good results and is sufficiently accurate for a rough design of the machine. KW - ransverse flux machine, passive rotor, magnetic equivalent circuit, conformal mapping, Schwarz- Christoffel transformation Y1 - 2020 U6 - https://doi.org/10.1109/icem49940.2020.9271065 SN - 2381-4802 SP - 721 EP - 727 PB - IEEE ER -