Articles (RICE)

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Showing 1 - 20 out of 322 results

Design of a 65-kW Wireless Charging Station Characterized by Optimal Load Impedance Tracking Control
(2025) Zavřel, Martin; Drábek, Pavel; Kindl, Vladimír; Frivaldský, Michal
This article presents the design and development of a low-level control approach for a wireless charger intended for modern electro-mobility (e-mobility) applications. It outlines future trends in the e-mobility market and technical advancements in wireless power transfer (WPT) systems, aligning them with the proposed wireless charger design methodology. A key advantage of the proposed solution is its full competitiveness with conventional wired charging stations. The primary focus of this work is the control system design for the wireless charging station (WCS), which features active and optimal load impedance tracking. This tracking adapts to varying load parameters (such as battery characteristics) and misalignments in coupling elements, ensuring maximum power transfer efficiency and high-power transfer controlled by supply voltage. The system complies fully with the SAE J2954 standard for wireless charging in e-mobility. The developed test system achieves power transfer of up to 65 kW across an air gap of 15 to 25 cm, with an overall system efficiency exceeding 95.5%.
Improving Manufacturing Processes through Artificial Intelligence - Example of Printed Circuit Board Manufacturing
(2025) Tupa, Jiří; Benešová, Andrea; Steiner, František; Řeřicha, Tomáš
The advent of Artificial Intelligence (AI) in manufacturing has heralded a new era of industrial revolution, characterised by unprecedented efficiency, productivity, and innovation. This critical review delves into the application of AI technologies in the manufacturing sector, scrutinising their impact on process enhancement and addressing the spectrum of opportunities and challenges they present. By thoroughly analysing recent studies, industry reports, and case examples, this paper outlines the transformative potential of AI in various manufacturing domains, including predictive maintenance, supply chain optimisation, quality control, and intelligent manufacturing. However, the paper does not shy away from discussing the critical challenges facing the deployment of AI in manufacturing. These include technical limitations, data privacy and security concerns, the need for substantial investment, and the socio-economic implications of workforce displacement and skill gaps. Concluding with a forward-looking perspective, the review suggests practical strategies for overcoming these hurdles, such as fostering public-private partnerships, investing in AI literacy and training, and adopting ethical guidelines for AI use.
Proton reconstruction with the TOTEM Roman pot detectors for high-β∗ LHC data
(2025) Hayrapetyan, A.; Georgiev, Vjačeslav; Hammerbauer, Jiří; Linhart, Richard; Peroutka, Zdeněk; Urban, Ondřej; Vavroch, Ondřej; Zich, Jan; CMS, Collaboration; TOTEM, Collaboration
The TOTEM Roman pot detectors are used to reconstruct the transverse momentum of scattered protons and to estimate the transverse location of the primary interaction. This paper presents new methods of track reconstruction, measurements of strip-level detection efficiencies, cross-checks of the LHC beam optics, and detector alignment techniques, along with their application in the selection of signal collision events. The track reconstruction is performed by exploiting hit cluster information through a novel method using a common polygonal area in the intercept-slope plane. The technique is applied in the relative alignment of detector layers with μm precision. A tag-and-probe method is used to extract strip-level detection efficiencies. The alignment of the Roman pot system is performed through time-dependent adjustments, resulting in a position accuracy of 3 μm in the horizontal and 60 μm in the vertical directions. The goal is to provide an optimal reconstruction tool for central exclusive physics analyses based on the high-β* data-taking period at √(s) = 13 TeV in 2018.
Transmission energy dispersive X-ray diffraction as a tool for the laboratory study of fast processes in metals
(2025) Vavřík, Daniel; Georgiev, Vjačeslav; Jakubek, Jan; Mašek, Bohuslav; Urban, Ondřej; Sleichrt, Jan; Kytyr, Daniel
In this work, an in-situ study of phase transitions in low-carbon steel is presented. The phase changes were monitored by the transmission energy dispersive X-ray diffraction technique during the heating, annealing and quenching cycle of the sample under standard laboratory conditions. During energy dispersive X-ray diffraction, the sample volume was transmitted with a pencil beam generated by a standard polychromatic X-ray tube without any spectral filtering. Two-dimensional polychromatic diffraction images were acquired by a Timepix 3 pixelated detector. This detector is capable of achieving a throughput of up to 38 Mhits/s in continuous stream mode using USB 3.0 interface. For each detected photon, its position is known with an accuracy of 55 μm in the detector plane and its energy with a resolution of 4 keV at 60 keV. The recorded polychromatic data is then recomputed to get the equivalent monochromatic XRD pattern that would be produced using a monochromatic X-ray source. Thanks to the 90 kV voltage potential of the X-ray tube, the polychromatic pencil beam wasable to pass through a highly attenuating sample made of 1.5 thick steel sheet. In addition, by utilizing the entire X-ray spectrum, the pencil beam has a sufficiently high brilliance to obtain XRD patterns rapidly enough to investigate relatively fast processes with temporal resolution of 10 s. It made to possible to analyze the phase transitions in a polycrystalline sample during its temperature treatment under standard laboratory conditions.
Overloadability improvement of electric motorcycle eDrive by using a five-phase PMSM
(2025) Frank, Zdeněk; Laksar, Jan; Hruška, Karel
This article addresses the replacement of the original three-phase permanent magnet synchronous motor for an electric motorcycle by a five-phase PMSM in terms of improving its verloadability and efficiency. The overloadability improvement is achieved by a novel approach utilizing the fundamental pro erties of the multiphase windings while keeping possibly most similar magnetic circuit topology. On the basis of previous work, a five-phase machine is designed, manufactured, measured and compared with the original three-phase machine. On the basis of measured data and calculated machine characteristics, the benefits of an increased number of machine phases are discussed as well as the proof of usability and benefits of used design approach.
Effect of open phase condition on asynchronous machine
(2025) Skala, Bohumil; Kindl, Vladimír; Frivaldský, Michal; Sobotka, Lukáš; Zavřel, Martin
This paper investigates the influence of an asymmetrical power supply on induction machines, focusing on key parameters such as temperature rise, torque, efficiency, and power factor. Various three-phase voltage asymmetries are examined to determine their impact on the magnitude of the negative-sequence voltage component. The study further explores how a drop in phase voltage leads to a significant negative component, the effect of phasor rotation from its ideal position, and the number of phases subject to voltage drops or phase shift errors. A voltage synthesis approach is employed to analyse the roles of the positive and negative components, with one component held constant to evaluate the resulting changes in power factor, efficiency, and torque. In addition, a dynamic thermal model is implemented to assess the machine’s temperature rise under load conditions.
Decay Heat Uncertainty Analysis for VVER Spent Nuclear Fuel
(2025) Lovecký, Martin; Závorka, Jiří; Kořínek, Tomáš; Škoda, Radek
Total Monte Carlo (TMC) extends the Monte Carlo method, using stochastic techniques and random sampling to solve the Boltzmann transport equation in spent nuclear fuel (SNF) depletion analysis. TMC evaluates the impact of uncertainties in nuclear data, such as cross sections and fission product yields, on SNF characteristics, focusing on decay heat, which is crucial for SNF handling and management. TMC generates random nuclear data variations within uncertainty ranges for Monte Carlo simulations, resulting in outcome distributions (e.g., decay heat) that reflect real-world behavior uncertainties. The uncertainty analysis examined a standard VVER-440 nuclear fuel. Using the serpent 2 code and referencing the endf/b-viii.0 and tendl nuclear data libraries, the study focused on the impact of cross sections and fission product yield nuclear data uncertainty on the decay heat of a standard VVER-440 nuclear fuel. The time frame chosen for both post-reactor shutdown and long-term for spent fuel cask loading is chosen, providing a comprehensive view of the nuclear fuel cycle.
Partial discharge behavior and insulation failures detection in electrical devices subjected to impulse voltage excitation
(2025) Eckert, Manuel; Mraz, Petr; Ballweg, Christof; Pihera, Josef
Partial discharges can occur within an insulating system due to flaws in the material and can cause continuous deterioration until a full breakdown occurs. Modern insulating systems are subjected to various forms of pulse voltage excitation, mainly due to the switching of modern power electronics. The recent introduction of wide-bandgap semiconductors increases this stress by enabling higher operating voltages and steeper switching transients than silicon-based semiconductors. Within this paper, partial discharge measurements are performed to investigate the discharge behavior of different partial discharge sources at impulse voltage excitation, aiming to find characteristic features. The presented method relies on measuring the conducted electrical signal of a partial discharge and can, therefore, access all quantities known from partial discharge measurements at sinusoidal voltage. This article introduces the high voltage measurement setup and the signal processing required. Experiments on four different partial discharge sources are performed, and the measured data are evaluated for the information they possess regarding the active discharge mechanisms. With the results obtained, the fault analysis can be extended to recognizing the fault type active at pulse voltage, utilizing partial discharge measurements.
Dynamic wireless power transfer in E-mobility using AC power bus and matrix converter: implementation suitability study
(2025) Zavřel, Martin; Kindl, Vladimír; Frivaldský, Michal; Skala, Bohumil
Presented paper discusses power distribution bus of dynamic wireless charging track for e-mobility applications. The focus is applied to the matrix converter and AC power distribution bus adaptation. The key behavior of matrix one-to-one phase converter and three-to-one phase converter is presented to get topologies for adaptation. Get matrix converter features are discussed regarding to the wireless power transfer and dynamic charging in electromobility. Feasibility of power topologies and control approaches are discussed as well. Proposed dynamic charging using three-phase matrix converter adaptation is compared to the conventional topologies using DC power distribution bus and corresponding inverters topologies. Knowledge taken from literature and theoretical discussion is verified by MATLAB–Simulink simulations and by basic experiments. Finally, feasibility study decisions are made in conclusion.
Special Experimental Environment for Generation IV Reactors with Graphite Reflector
(2024) Vilímová, Eva; Peltan, Tomáš; Škoda, Radek
Nowadays, there is an increasing demand for new small modular reactors (SMR) reactors with a wide range of applications, often classified as a new Generation-IV reactors. Unfortunately, there is no commercially operating nuclear reactor meeting the characteristics of Generation-IV reactors in its technical design and features. However, Generation-IV nuclear reactors are intensively developed worldwide, including the Czech Republic. To support research activities linked with the development of these reactors, an appropriate experimental environment and resources simulating conditions expected in Generation-IV reactors with graphite are needed This work builds on previous research and presents a special arrangement of the LR-0 reactor core with a double-row graphite reflector, on which the influence of graphite on the neutron field shaping and power distribution was experimentally and computationally verified. The main reason for this article is to investigate the effect of the graphite reflector, which will serve as a support for the development of neutron instrumentation for Generation-IV reactors and other support for Generation-IV research activities. The results confirm the conclusions of previous research and also provide a better knowledge of the double-row graphite reflector neutron field. The presented and tested LR-0 core arrangement is included in a set of experiments supporting the research of reactor cores with graphite reflectors.
Electrically switchable magnetic elastomer
(2025) Sodomka, Ondřej; Mach, František
The magnetorheologic elastomers (MREs) have emerged as valuable materials in soft robotics, especially on small scales, where their responsive magnetic properties enable precise control and enhanced adaptability. In this paper, we focus on the design, composition, and magnetic properties of a multicomponent electropermanent elastomer (EPE) that can be switched between on and off states by an external magnetic field source. The EPE is composed of two ferromagnetically hard NdFeB particles coupled together with strontium ferrite microparticles (SF-D360) with different magnetic coercivity and remanent flux density. The resulting EPE has a bistable magnetic behavior, enabling the device to be energy efficient. This unique feature positions EPEs as highly efficient alternatives to conventional electromagnetic systems in fields such as robotics, automation and medical devices, where precise magnetic control and low power requirements factors are essential.
Lifetime Behavior of Turn Insulation in Rotating Machines Under Repetitive Pulsed Stress
(2025) Zedan, Ousama Ahmed Abdalla; Haller, Rainer; Trnka, Pavel; Bärnklau, Hans
Insulation materials are critical for the reliability and performance of electrical power systems, particularly in high-voltage rotating machines. While failures can arise from thermal, mechanical, or electrical stress, they predominantly manifest as electrical breakdowns. Prior research has primarily concentrated on aging in straight winding sections, despite evidence indicating that failures frequently occur in the bending regions of turn insulation. This study explores the influence of high-frequency pulsed electrical stress on the lifetime behavior of Type II insulation systems used in high-voltage rotating machines. Practical samples, designed with geometric configurations and technology akin to that in rotating machines, were tested under conditions characterized by voltage slew rates (dv/dt) exceeding 10 kV/mu s, with variations in frequency and waveform shape. The findings reveal that the rate of electrical aging remains consistent across differing pulse widths, risetimes, and polarities, displaying a similar lifetime exponent. Nonetheless, insulation durability is markedly more compromised under pulsed conditions. At the identical times-to-failure, the sinusoidal waveform necessitated nearly twice the applied peak voltage as the bipolar pulse waveform. This finding clearly suggests that pulsed excitation exacerbates insulation degradation more effectively due to the sharp rise times and high (dv/dt) rates imposing substantial electrical stress on dielectric materials.
Search for central exclusive production of top quark pairs in proton-proton collisions at √s=13 TeV with tagged protons
(2024) Tumasyan, A.; Georgiev, Vjačeslav; Hammerbauer, Jiří; Linhart, Richard; Peroutka, Zdeněk; Urban, Ondřej; Vavroch, Ondřej; Zich, Jan; Totem, Collaboration; CMS, Collaboration
A search for the central exclusive production of top quark-antiquark pairs (t (t) over bar) is performed for the first time using proton-tagged events in proton-proton collisions at the LHC at a centre-of-mass energy of 13TeV. The data correspond to an integrated luminosity of 29.4 fb(-1). The t (t) over bar decay products are reconstructed using the central CMS detector, while forward protons are measured in the CMS-TOTEM precision proton spectrometer. An observed (expected) upper bound on the production cross section of 0.59 (1.14) pb is set at 95% confidence level, for collisions of protons with fractional momentum losses between 2 and 20%.
Surrogate-based heat transfer modeling for important parts in a fully enclosed traction motor
(2025) Fiala, Václav; Pechánek, Roman
The aim of this paper is to present a heat transfer modeling method that combines analytical calculation with numerical simulation. This method can be referred to as hybrid modeling or surrogate-based modeling. The object under study is a fully enclosed water-cooled traction motor. The selected investigated regions that are adjusted by numerical simulation are the end-winding region and the interface of the stator core and water jacket. The end-winding region is investigated because end windings are located at the enclosed inner part, where it is difficult to analytically determine the airflow velocity (velocity distribution). The transition between the stator core and the water jacket is also important, as it directly determines the cooling efficiency due to the cooling method where the water jacket is placed on the stator core. This paper presents a heat transfer calculation example for these two critical areas, along with validation using real motor data obtained temperature rise test, comparing the calculated results with measurements.
Timepix4 chipboard and readout concept
(2025) Růžička, Ondřej; Burian, Petr; Broulím, Pavel; Bergmann, Benedikt; Kulhánek, Tomáš; Farkaš, Martin; Smolyanskiy, Petr
This paper presents a modular readout and chipboard concept developed for the Timepix4 hybrid pixel detector, a high-performance ASIC featuring 448 x 512 pixels and sub-nanosecond timing resolution. Building on the success of Timepix3, Timepix4 supports both frame-based and data-driven acquisition modes with data rates up to 3.6 MHits/mm2/s and 195 ps time binning. The chip can be integrated via wire-bonding or Through-Silicon-Via (TSV) technology, allowing full four-side tiling for scalable detector arrays. The modular chipboard system, consisting of a detector module and a baseboard, simplifies power delivery and data transmission using a single 12 V supply and Ethernet-style cabling. A commercial FPGA-based readout supports up to four detectors with Gigabit Ethernet and PCIe interfaces. The concept was successfully validated at CERN SPS with heavy-ion beams, demonstrating system stability and high data integrity. Ongoing development focuses on enhanced power and cooling systems, multi-chip integration, and improved software support for advanced experimental setups.
State-Dependent Neural Flux Linkage Models of Synchronous Machines
(2025) Ševčík, Jakub; Šmídl, Václav; Glac, Antonín
Flux linkage maps (FLMs) are routinely used in high-precision control and modeling of synchronous machines. Common methods often consider only the dependence of the FLM on the stator currents, allowing for convenient representation in lookup tables or neural networks. However, the flux linkage also depends on speed, position, and other state variables. Although this is formally simple to add as an additional input to neural models of FLM, the estimation with additional inputs becomes more demanding. We demonstrate that the conventional approach of FLM training using the assumption of a steady-state regime is insufficient to learn the dependency on the rotor position. It is necessary to use the complete ordinary differential equation of the current to learn the FLM model. Even for a shallow neural model of the FLM, the estimation procedure yields a deep learning task known as neural ODE. This procedure essentially generates multistep ahead prediction of differential equations and minimizes the mismatch between the mathematical model and data. The efficiency of this approach is demonstrated on the FLM of a synchronous machine considering flux saturation, speed dependence, and slot harmonics. The proposed approach significantly improves current prediction, yielding improved deadbeat current control. The results are experimentally verified on a 4.5 kW laboratory prototype.
Compatibility Testing of New Insulating Fluids and Materials in Distribution Transformer
(2025) Trnka, Pavel; Hornak, Jaroslav; Trnková, Magdalena; Michal, Ondřej; Mokrá, Zdislava; Sláma, Pavel; Kopřiva, Jiří; Prosr, Pavel; Leffler, Jan; Frána, Zdeněk
The introduction of a new insulating oil or, for instance, a new type of insulation or sealing into a transformer necessitates tests for material compatibility. Compatibility tests of liquids with the structural internal materials of transformers are conducted to prevent undesired interactions between insulating fluids and the formation of products that could lead to the generation of undesirable ions, sediments, or chemical compounds that result in a reduction in the dielectric property performance of the fluid. This includes chemical reactions (hydrolysis, hydrogenation, oxidation, formation of sulfates or sulfides, etc.) and degradation, the formation of conductive suspensions, the generation of undesirable condensation, and alterations in other fluid properties, such as interfacial tension between oil and water, viscosity, flashpoint, etc. Changes must also not occur in the strength and hardness of gasket material, which could result in undesirable fluid leakage. This paper describes the novel methodology and results of several proposed tests, including the impact on oil viscosity, material hardness, FT-IR analysis of oils, partial discharges in different oils, dielectric properties, and more, conducted during compatibility and aging tests at 120 degrees C and 140 degrees C performed on materials used in particular distribution transformers being prepared for natural ester use. The results show notable differences in the behavior of insulating fluids and aged submerged materials. While mineral oils exhibit lower dissipation factors compared to natural esters, the latter demonstrate slower and less severe hardening effects on gaskets during high-temperature aging (e.g., Shore 35.25 in mineral oil vs. 21-22.5 in natural esters). The tensile strength of the tested cable ties decreased significantly (from 260 to approx. 60 N) in mineral oil but increased in natural ester (320 N/120 degrees C exposition). This study also highlights a novel insight into partial discharge mechanisms, where differences in viscosity, conductivity phenomena, and dielectric constants result in presented differences in inception voltages and prebreakdown activity.
Katherine Generation 2: advanced readout system for Timepix3 detectors
(2025) Burian, Petr; Broulím, Pavel; Bergmann, Benedikt; Farkaš, Martin; Jára, Martin; Růžička, Ondřej; Smolyanskiy, Petr; Mánek, Petr
This paper presents Katherine Generation 2 (Gen2), an advanced readout system designed for Timepix3 pixel detector. The new system addresses limitations of the original Katherine (Gen1) design, particularly in terms of data throughput and support for multi-detector configurations. Katherine Gen2 supports two sensor inputs via VHDCI connectors and provides two independent bias voltage sources up to +/- 1 kV. It includes both Gigabit Ethernet and USB 3.0 interfaces, offering flexibility for remote or local high-throughput applications. Data handling pipeline has been extended to support dynamic detector mapping, hardware decoding of pixel data, and timestamping of external triggers. Compatibility with multiple chipboard types, including single-chip, quad (2 x 2), and specialized detector units, is maintained. Benchmark measurements demonstrate that the system achieves the maximum data rate supported by the Timepix3 chip in USB 3.0 mode. The device is supported by established software tools and is intended as a flexible platform for various experimental and detector development applications.
Technology for direct assembly of SMD components in stretchable textile electronics realized by printing
(2025) Janda, Martin; Pretl, Silvan; Řeboun, Jan
In this article, a novelty direct assembly method for stretchable e-textile electronics based on printed technologies is presented. Presented technology utilizes the assembly of components directly into the wet base layout paste, without any interfacing contact material (such as conductive adhesive). Such assembly reduces the number of technological steps and exhibits more reliable behavior, as the number of interfaces is reduced and the conductive material is highly stretchable. Components are encapsulated using flexible encapsulation and the whole electrical system is realized on a foil, which is then thermo-transferred to the textile substrate. Samples are subjected to the bend test and cyclic stretch tests. Direct assembly is proven to be robust enough, as its increase of resistance during cyclic stretch testing is much lower (17% after 500 cycles) than assembly with isotopically conductive adhesive. Direct assembly also exhibits rapid regeneration of resistance after the end of mechanical load. In addition, a low and sufficient contact resistance of around 100 mΩ is achieved.
Design issues of a passive shielded WPT prototype with regard to safety limits against EM radiation
(2025) Schönfelder, Tristan; Kindl, Vladimír; Frivaldsky, Michal
This paper presents the development and optimization of a passively shielded WPT (Wireless Power Transfer) prototype that ensures compliance with the international limits for magnetic field exposure of the ICNIRP (International Commission on Non-Ionizing Radiation Protection) and the IEEE/ICES (International Committee on Electromagnetic Safety). The aim is to optimize material consumption, weight and costs when building a WPT prototype by following a structured approach and using software-based methods such as finite element analysis (FEA), without compromising safety and energy transmission efficiency. For this purpose, different ferrite shielding arrangements are examined and evaluated on the basis of various parameters. In addition to the shielding, the selection of suitable materials and the design of the overall system is a central topic. By comparing the simulation and measurement results, the functionality of the defined procedure for creating a WPT setup is demonstrated.

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