Conference papers (RICE)
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Item Study of Dielectric Strength of Ceramic Substrates for Power Electronics(IEEE, 2025) Kupilík, Tomáš; Kvasnička, Petr; Hlína, Jiří; Pihera, Josef; Prosr, Pavel; Řeboun, JanThis paper is focused on a detailed study of dielectric strength and surface and inner morphology of ceramic substrates for power electronics applications. Dielectric strength is a key parameter in this field. It depends on the type of ceramic material and substrate thickness. The presented study includes five types of ceramic substrate material and five different thicknesses of substrate. The results of dielectric strength measurement depend on ceramic material and substrate thickness and related to morphology are described in this paper.
Item Comparative Analysis of Dielectric Properties of Polyethylene and Polypropylene with Flame Retardants for Cables(IEEE, 2025) Kadlec, Petr; Šipla, Jan; Polanský, RadekModern sustainable cable insulation development increasingly emphasises recyclable materials, and widely used cross-linked polyethylene-based materials are often identified as problematic regarding low recyclability. Alternatives with better recyclability, such as polyethylene (PE) without cross-linking and polypropylene (PP), are being explored, particularly regarding their flame retardancy. This study evaluates the dielectricproperties of PE and PP filled with 5 wt% of aluminium hydroxide (ATH), magnesium hydroxide (MDH), or halloysite nanotubes (HNT). The characterisation and comparison of all tested materials were performed based on measurement of volume resistivity, dielectric strength, dielectric constant and dissipation factor. The volume resistivity of polymers decreased minimally with the addition of flame retardants, while the dissipation factorincreased, especially for HNT-filled polymers, but remained at an acceptable level. PE exhibited higher dielectric strength than PP, with MDH further enhancing this property in both materials, while ATH improved it only in PE. The tested filling level of ATH or MDH does not deteriorate the dielectric properties of PP and may even improve them, especially the dielectric strength; therefore, the tested PP-based composite becomes a viablealternative to conventional cable insulation materials.Item Evaluation IoT Platform for Textile-Based Elements(IEEE, 2025) Handrejch, Jan; Blecha, TomášThis paper presents the design of an IoT test platform developed for the testing and visualization of textile-based electronic components. The system integrates various textile peripherals, including flexible LED ribbons, textile antennas for sub-GHz band (ISM), and fabric-embedded sensors, enabling real-time monitoring, data acquisition, and performance assessment in dynamic environments. The platform is built around an ESP32 microcontroller, featuring a LoRa module based on the SX1278 chip (862-931 MHz) for long-range wireless connectivity. Additionally, it supports Wi-Fi and Bluetooth, offering flexible communication options depending on application needs. It includes I2C, SPI, and UART interfaces, ensuring seamless integration with textile-based sensors and other peripherals. A rechargeable battery with monitoring enables autonomous operation, making the system suitable for portable and wearable applications. To enhance communication reliability, the platform incorporates specialized error-correction algorithms, reducing the impact of signal degradation in textile-based interconnects. The platform facilitates the evaluation of textile antennas, sensor performance, and RF behavior in sub-GHz ISM bands, such as 868 MHz, commonly used in IoT and wireless sensor networks. The acquired data is processed and can be visualized in real time, providing valuable insights into the feasibility of textile-integrated electronics for smart fabric applications, wearable technology, and scalable textile IoT solutions.Item Estimation of Damping Effects in a Salient Pole Synchronous Machine without a Damper Using SSFR Testing with a VSI(IEEE, 2025) Rozhon, Ondřej; Janouš, Štěpán; Cibulka, JiříAccurate estimation of damping effects in salient pole synchronous machines is essential for improved modeling and stability analysis. Although the application of the Standstill Frequency Response (SSFR) method to machines without damper windings has been discussed in previous studies, this work focuses on demonstrating its practical applicability using a Voltage Source Inverter (VSI) with a sine filter to ensure highquality excitation signals. The objective is to evaluate whether SSFR can effectively capture damping phenomena arising from eddy currents and magnetic saturation in the pole structure, even in the absence of explicit damper bars. Experimental tests are carried out under controlled standstill conditions, and the resulting frequency responses are analyzed to identify dampingrelated characteristics. The results confirm that, with proper excitation and measurement setup, the SSFR method remains valid for such machines. This study contributes by validating a practical, inverter-based approach for SSFR testing, offering enhanced precision and applicability in modern synchronous machine analysis.Item Knitted Bow-Tie Frequency Resonators with Hybrid Conductive Threads for Wearable Strain Monitoring(IEEE, 2025) Radouchová, Michaela; Kalaš, David; Blecha, Tomáš; Marterer, Verena; Fröhlich, AdélaThis paper presents the development of knitted frequency resonators designed for strain monitoring in wearable e-textile applications. These textile frequency resonators, knitted from basic 100 % cotton and conductive hybrid yarns, are suitable for e-textiles. Frequency resonators were designed as bow-tie antennas and are stretchable thanks to the knitted structure. Electrical parameters change due to the elongation of the conductive structure; this causes a shift in the resonant frequency. The resonant frequency decreases as a function of elongation.Item Two-step predictive control of delta-connected CHB-based parallel active power filter(IEEE, 2025) Kehl, Zdeněk; Glasberger, Tomáš; Peroutka, ZdeněkThis paper presents a novel control strategy for a shunt active power filter (SAPF) based on a delta-connected cascaded H-bridge (CHB) topology, aimed at addressing two major challenges: high computational demands of model predictive control (MPC) in multilevel converter systems and the need for reliable compensation of current harmonics and reactive power under dynamic grid conditions. The proposed solution combines a computationally efficient two-step finite control set MPC with a modified instantaneous active–reactive power theory. This approach eliminates the need for weighting factors and enables implementation on low-cost digital signal microcontrollers. The effectiveness of the method is validated experimentally using a 60 kW laboratory prototype with a 200 MHz microcontroller. Results confirm fast dynamic response and significant harmonic reduction.Item Test Rig for Investigation of New Generation of 3.3kV SiC MOSFET Based Traction Converters(Mesago PCIM GmbH, 2025) Peroutka, Zdeněk; Drábek, Pavel; Molnár, Jan; Jára, Martin; Peroutka, Aleš; Janouš, Štěpán; Suchý, Ondřej; Mitsui, Yohei; Morisaki, Shota; Horiguchi, Takeshi; Mukunoki, YasushigeThis paper introduces the test rig for investigating high-power full-SiC traction converters equipped with 3.3kV SiC MOSFET power modules developed by Mitsubishi Electric. The traction converter has been configured as a 3-phase 2-level voltage-source converter employing two power modules in parallel, which is the most common topology in the target traction applications with a rated dc-link voltage of 1.5 kV. The test rig allows complex testing of the traction converters under full-power (> 1 MW) and full-voltage conditions (dc-link voltage up to 2.4kV). The converter under the test can be loaded by both passive RL load and 3-phase ac traction motor mechanically coupled with the variable speed drive emulating arbitrary mission profile. The parallel power module operation in the converter legs aims to investigate unbalanced behavior (currents, temperatures) between SiC modules during critical traction inverter operating conditions. The test rig design makes possible easy changes of the traction converter as well as its auxiliary systems setup – e.g. variable gate driver parameters (Rgon, Rgoff, Lg), liquid cooling system allowing independent control of a junction temperature for each power module in parallel and precisely pre-set temperature difference between power modules under investigation, both artificial mis-sion profiles as well as mission profiles recorded on the real tracks.Item Enhancing E-Textile Reliability: A Comparative Study of SMD-Ribbon Joints Protections Against Sweat(Trans Tech Publications Ltd, 2025) Hirman, Martin; Navrátil, Jiří; Hladíková, Julie; Steiner, FrantišekThe reliability of electronic-textile (e-textile) systems is critically influenced by environmental factors such as sweat, which can compromise the performance of smart textile garments in sports and healthcare applications. This study investigates the durability of joints between surface-mount device (SMD) chip resistors and conductive textile ribbons under accelerated aging conditions simulating exposure to synthetic sweat. Two types of sample protection were evaluated: basic encapsulation using a UV-curable adhesive, and additional protection employing seam-sealing textile adhesive tape. SMD resistors were attached to silver-coated copper microwire ribbons using a specialized contacting technique, and their joint resistance was monitored across four cycles of immersion in acidic synthetic sweat, highhumidity aging, and drying. Results demonstrate that while joints with only basic protection exhibited increasing electrical resistance and frequent failures after repeated aging cycles, those with additional seam-sealing protection maintained low and stable resistance, with no observable degradation. These findings confirm that the interface between textile substrates and electronic components is a critical failure point in e-textile systems, and that the use of seam-sealing adhesive tape significantly enhances connection reliability and longevity. The presented contacting and protection approach is recommended for robust integration of SMD components in smart textiles intended for demanding environments.Item Reliability of E-Textile Conductive Paths and Passive Component Interfaces(Trans Tech Publications Ltd, 2025) Hladíková, Julie; Hirman, Martin; Navrátil, JiříE-textiles are subjected to harsh environmental conditions such as perspiration, mechanical abrasion, repeated washing and drying cycles, stretching, moisture, and temperature fluctuations. This study focuses on evaluating the durability of stretchable textile conductive ribbons composed of silver-coated microwires, particularly the electrical resistance of these ribbons and their connections to passive components after repeated washing. Thewashing process exposes textile electronics to combined mechanical, chemical, and thermal stress.Item Test Stand for Evaluation of Directivity of the Gas Ultrasonic Transducers(IEEE, 2025) Švarný, Jiří; Sýkora, MartinFor years, the ultrasonic transducers are used in various applications including obstacle detection, level, flow and distance measurements. Some of the measuring devices require pairs of the ultrasonic transducers working together. The gas flowmeters can be named as a typical example. The equality of the parameters of the transducers working in the pair is very important here. During work on new generation of gas flowmeters there was necessary to couple the transducers at first. That is why, we developed laboratory test stand for evaluation of features of gas flowmeters. The device consists of the mechanical support for the transducers and PC controlled high voltage pulser. The design and implementation of the device is described in the paper.Item Transformerless Ultrasound Modem Frontend Using Resonant Filter for Voltage Boost(IEEE, 2025) Nigg, Stephan; Peroutka, ZdeněkIn recent years, an increased interest in underwater communication has been observed. In the countless publications not only new methods of acoustic communication but also low cost designs of suitable modem platforms have been proposed. As modems that are commercially available either are not open enough to design new methods on or are simply too expensive. Many designs share a common design principle: The high voltage used to drive the ultrasound transducer is generated by a transformer. Core material, wire diameter and winding counts must be defined. A transformer can get large and heavy and is often a costly factor in a bill of material. This paper presents a full design concept on how to eliminate the use of transformers without sacrificing the ability to drive several hundred volts. As an example a 40 kHz system is shown but the design principle can be adapted to a wide range of transducers and frequency bands.Item Magnetic Actuation of Miniature Robots on Planar Surfaces: Mathematical Modeling and Estimation(University of West Bohemia, 2022) Koua, Kadio Ettien Jean; Mach, FrantišekMagnetic actuation methods in miniature robots are widely used thanks to their wide applications for precise micro-manipulations in inaccessible or hardly accessible environments, including medical and biological operations. The system studied is composed of miniature robots with permanent magnets inside the body and a planar coplanar coils actuator. This paper investigates the mathematical modeling of a robot's movement, taking uncertainties and unmodeled dynamics into account. The crucial parameter is the friction coefficient between the planar actuator and the robot as it moves. An approach has been proposed to estimateit using the Kalman filter principle. Numerical simulations are compared to experiments to illustrate the effectiveness of the proposed approach.Item Optimisation of PV system energyefficiency with take into account technical conditions(Instytut vidnovliuvanoyi enerhetyky NANU, 2024) Bělík, Milan; Rubanenko, Olena; Rubanenko, O.; Klochkov, A.This paper considers the rates of increase in the installed capacity of photovoltaic systems in Ukraine and in the world according to the International Renewable Energy Agency (IRENA) and nternational Energy Agency (IEA). A comparative analysis of the technical characteristics of monocrystalline photovoltaic modules operated in the Czech Republic and Ukraine under similar meteorological conditions is presented. Possible reasons for the decrease in the energy efficiency of photovoltaic modules and ways to solve them are onsidered. It is established that biological corrosion reduces the energy efficiency of the photovoltaic module and initiate the development of other defects.Item Numerická analýza olejového transformátoru plněného biodegradabilním olejem(TechSoft Engineering, spol. s r.o., 2024) Sobotka, Lukáš; Leffler, JanV současné době je společností vyvíjen tlak na udržitelnost a ekologičnost jednotlivých zařízení. Z tohoto důvodu v minulosti vznikly některé Evropské direktivy, cílící na zvýšení účinnosti, v tomto případě účinnosti transformátorů. Tento článek popisuje numerický model chlazení takto navrženého transformátoru navíc chlazeného přírodním esterem ENVITRAFOL.Item Fast Earth-Fault and Feeder Detection in Medium-Voltage Distribution Power Grids(IEEE, 2023) Štengl, Josef; Komrska, Tomáš; Peroutka, ZdeněkSafety and reliability of medium-voltage distribution power grids depend on the rapid detection and elimination of faults. The most common faults in MV power grids are single-phase earth faults. Traditional methods for faulty feeder detection are not fully reliable and their sensitivity must be increased by connecting of an auxiliary resistor, which cancels the compensation of the fault current. Simple, fast, and reliable algorithms for both, earth fault and faulty feeder detection in MV distribution power grids are proposed in this paper. The methods are based on computation of angle between feeder currents using a dot product, they are computationally efficient and eligible for real-time environment. Their performance is verified on the set of 154 earth fault records, measured in a MV distribution power grid of 22 kV.Item Dynamic Wireless Charging Using LCC-S compensation topology in Low and Medium Power Applications(IEEE, 2023) Zavřel, Martin; Kindl, Vladimír; Tyrpekl, MiroslavWireless power transfer in battery charging mode or in direct supplying mode is high actual theme of these days. Dynamic wireless power transfer as charger or supply is highly cited especially in electro mobility nevertheless, it has also place in another applications as autonomous transfer systems, linear tracks, more axis linear tracks, linear tracks for robot’s act., where a receiver size is set by application. To ensure high charging line modularity and the technology grasp in the automation area, an adequately small receiver is required. A Dynamic wireless charging is specific by large number of transceivers stored behind each other in the charging line – called segmented dynamic wireless charging. In presented paper, the theoretical background, simulation analysis and laboratory testing results is providing out to optimize charging line for automation applications. The key considered means of achieving satisfactory results are segment grouping in transceiver charging line and wireless power transfer compensating topology. Results are summarized to the optimal grouped segmented dynamic wireless power transfer system design.Item Control strategy for simulator moving platform with enhanced reliability(University of West Bohemia, 2023) Kehl, Zdeněk; Glasberger, Tomáš; Glasbergerová, VendulaThe primary objective of this paper is to design a control system for an indirect frequency converter for a linear actuator employed in a 6DOF moving platform, which finds utility in simulating vehicles, aircraft, and drivers' or pilots' training. To achieve the desired performance, the proposed control strategy for the indirect frequency converter aims to accomplish two crucial goals. Firstly, it must ensure a highly responsive actuator with exceptional dynamic characteristics. Secondly, it must establish appropriate electromagnetic compatibility with the grid and the possibility of energy recuperation. Considering that the simulator is intended to be used in collaboration with a training crew, it becomes paramount to prioritize the reliability and safety of its operation. However, ensuring the reliability of the linear actuator's winding (slider) position sensor, which can be particularly challenging in this context, is crucial. As a solution, the control algorithm of the converter's output section has been extended to incorporate sensorless position and velocity estimation. This addition addresses the challenge of the position sensor mechanical installation and enhances the system's overall reliability. Selected experimental tests proved the proposed converter control system.Item Increasing Operation Flexibility of Backpressure Turbine in Cogeneration Plant by TES: Case Study(University of West Bohemia, 2023) Hromádka, Aleš; Vinš, MartinThere is proposed an idea and evaluated a case study of cooperation of thermal energy storage (TES) and backpressure turbine in this paper. The main focus is paid on separation of the link between production and utilization of thermal energy as well as electrical energy by backpressure turbine. An overview of the thermal energy storages was elaborated, and optimal storage was evaluated on real operation data from combined heat and power plant as a case study. Case study results are discussed in the conclusion.Item Digital Transformation of Electrical Engineering Companies in the Czech Republic(Springer Cham, 2024) Benešová, Andrea; Steiner, František; Tupa, JiříCompetitive yet sustainable production will be a real challenge for companies, especially in the current market conditions that have been affected by the covid-19 pandemic. In the future, if companies want to stay in the market and be competitive, they will have to adapt their production to requirements such as the Industry 4.0 concept, one of the benefits of which is to increase the productivity of companies and a relatively fast return on investment. For this reason, the main objective of this paper is to find out the current status of enterprises in the electrical manufacturing sector in terms of implementing the Industry 4.0 concept. The findings were made through a questionnaire survey in which 50 companies from this sector participated. Surprisingly, the results of this survey showed that more than half of the respondents, despite all the possible benefits of the Industry 4.0 concept, are still not planning to implement it, while the remaining respondents are already in various stages of implementation. Moreover, although the Industry 4.0 concept has been discussed since 2011, the data showed that 20% of respondents are not familiar with the concept. The respondents who answered this way belonged to the group of micro or small enterprises, where this is understandable.Item SMD Components Recycling Procedure for Reuse in E-Textiles with Risk Analysis(Springer Cham, 2024) Hirman, Martin; Benešová, Andrea; Navrátil, Jiří; Steiner, František; Tupa, JiříThis paper deals remanufacturing method for the reuse of adhesive bonded SMD components on stretchable textile ribbons for integration in e-textiles and its risk analysis. Nowadays, e-waste is an increasing problem in the world, and reducing this problem by using circular economy principles and reusing components is beneficial. In our research, the samples were submitted for accelerated ageing by dry heat and their quality was evaluated by the electrical resistance measurement. The recycling procedure was realized four times, and the mentioned risk analysis was realized before and after the experiment. The two main goals of our research were determined. The first goal was to demonstrate the applicability of our recycling procedure and the quality of samples with reused components after accelerated climatic ageing by dry heat. The second goal was to create and verify the risk analysis of our method and identify actions to mitigate the high and very high risks. The experiment showed that our recycling method is applicable several times without decreasing product quality. The results also present that reused samples are functional like new even after samples dry heat ageing. The risk analysis after the experiment showed seven high risks, which is necessary to solve primarily. These risk factors and actions to mitigate them are described in the paper.
