Wireless Power Transmission System for Powering Rotating Parts of Automatic Machineries

This paper deals with the analysis of a suitable compensation topology of a wireless power transmission system for powering the rotating parts of modern automatic machine tools. It summarizes the important properties of the serio-parallel compensation topology suitable for this application and demonstrates a detailed mathematical derivation using the first harmonic approximation. The paper details the industrial implementation of the system in a specific automatic machine tool application and demonstrates the strong technical advantages of the proposed design. Important theoretical conclusions and technical assumptions made when considering the system layout are verified by experimental laboratory measurements and the final deployment of the technology in the professional tool DMU 40 eVo linea

RF power amplifiers for non-standard frequency bands

Práce si klade za cíl seznámit odbornou komunitu s moderními přístupy řešení z oblasti výkonové radiotechniky, výkonových vysokofrekvenčních zesilovačů a podpůrných obvodů pro tuto oblast. Tato disertační práce se zabývá výzkumem, návrhovými metodami a praktickým ověřením dosažitelných parametrů na prototypech a funkčních vzorcích výkonových vysokofrekvenčních zesilovačů. Tyto zesilovače jsou většinou zaměřeny pro tzv. nestandardní kmitočtová pásma (úseky) v oblasti krátkých a velmi krátkých vln, která zpravidla nejsou z hlediska komerčního využití příliš zajímavá. Ze stejného důvodu existuje i výrazně menší množství odborných publikací, které se danou problematikou vážně zabývají, protože vzhledem k povaze využití těchto pásem není zaručeno masové uplatnění výsledků a následný zásadní komerční úspěch.ObhájenoThis work informs the professional community with modern solutions of the power radio engineering, power amplifiers and support circuits for this area. This dissertation deals with research in power radiotechnics area for non-standard frequency bands. This non-standard radio bands are not in terms of commercial use of overly interesting. For this same reason, there is a significantly smaller number of professional publications that deal with this subject seriously, because the nature of use of these bands is not guaranteed by the mass application of the results and with high commercial success

High-Power and Wideband Radio-Frequency Dummy Load

A novel approach to designing dummy loads has been proposed that simplifies practical construction and simultaneously offers a satisfactory impedance matching over a wide frequency band for high-power radio-frequency applications. The concept involves a gradual impedance transformation of the guided electromagnetic wave to the short circuit using optimally shaped plates and making use of common tubular non-inductive resistors. Design process involves parametric analysis in a full-wave numerical simulator

Studie chlazení vysokovýkonných SiC prvků

Vysoce výkonné elektronické součástky jsou důležité prvky téměř všech moderních motorizovaných strojů. Tyto křemíkové komponenty jsou výrazně minimalizovány, zejména v odvětví dopravy. Koncentrace výkonu vyžaduje dokonalé chladicí podmínky. Běžně používaným principem je průtokové chlazení aktivním chladicím okruhem s chladiči. Dostatečné chlazení a rovnoměrné teplotní pole na teplosměnné ploše jsou rozhodující parametry pro udržitelnou funkci komponent z karbidu křemíku. Tato studie využívá pokročilé metody CFD k analýze současného stavu běžně vyráběných výměníků tepla a poskytuje nové přístupy optimalizací CFD v kombinaci s 3D tištěnými díly. Přístup založený na 3D tisku také umožňuje designovou inspiraci v přírodních principech. Biomimetická inspirace ukazuje širokou škálu tisíce let trvající optimalizace provedené přírodou. Výzkum v této oblasti nám může pomoci s vývojem povrchů pro lepší přenos tepla. Simulace přenosu tepla jsou ověřeny laboratorním měřením prototypových chladičů. Tyto techniky jsou prezentovány na jedinečném designu chladiče, který byl simulován, vyroben a měřen. Studie ukazuje CFD přístupy, popisuje detaily měření prototypu a zabývá se i negativními otázkami kovového 3D tisku.High-performance electronic parts are vital features in almost all modern motorized machines. These silicon components are significantly minimised, especially in transportation branch. Concentration of performance requires perfect cooling conditions. A fluid flow cooling by an active cooling circuit with heat sinks is a commonly used principle. Sufficient cooling and uniform temperature field on heat transfer area are crucial parameters for the sustainable function of Silicon-Carbide components. Producer of electric vehicles induces research in the field of coolers due to the requirements of installed SiC features. This study uses advanced CFD methods to analyse the current state of commonly manufactured heat exchangers and provides new approaches by CFD optimisation in combination with 3D printed replacement parts. Approach based on 3D print also allows design inspiration in natural principles. Biomimetic inspiration shows a wide range of thousands of years lasting optimisation made by nature. Research in this field can help us with the evolution of enhanced heat transfer surfaces. Developed coolers were examined by CFD techniques. Simulations of heat transfer are verified by laboratory measurement of prototype heatsinks. These techniques are presented on the unique de-sign of a heat sink which was simulated, manufactured, and measured. The study shows CFD approaches, describes details of prototype measurement, and also deals with negative issues of metal 3D print

Korekce oblique-angle oscillation pro laserový doppler vibrometry

Příspěvek popisuje navrženou korekční metodu pro vyhodnocení vibrací pro laserovou dopplerovou vibrometrii měřenou pod různými úhly. Krátce popisuje klíčový matematický přístup, přičemž povrch analyzovaného objektu je referenční rovinou a uvádí praktický příklad správné aplikace metody. Navrhovaná korekční metoda je prakticky ověřena laboratorním měřením vlastních kmitočtů a tvarů vibrací skříně vysokonapěťového transformátoru. Výsledky jsou dále porovnány s referenčním měřením pomocí kalibrovaných akcelerometrů.The paper proposes a correction method of the oblique-angle vibration for laser doppler vibrometry. It briefly discusses the key mathematical approach considering the surface of the analysed object to be a reference plane and gives a practical example of the method proper application. The proposed correction method is practically verified by laboratory measurement of natural frequencies and mode shapes for vibrations of high voltage transformer housing. The results are further compared to equivalent accelerometer measuremen

Design and construction of high-quality capacitor for high frequency and power application

The paper proposes a design and construction of a special plated capacitor exhibiting very good high-frequency characteristics. The capacitor is designed to minimize the parasitic parameters like ESR (equivalent series resistance) and ESL (equivalent series inductance) and to be suitable for power industry applications. The paper describes the fabrication process and discusses technical issues related to technology of manufacturing and assembling. It also provides an experimental verification and the quality evaluation based on frequency characteristics compared to existing commercial high-quality capacitor

Experimental verification of the finite element analysis of an induction machine with implemented static eccentricity fault

The paper deals with the experimental verification of vibration frequency spectra of squirrel-cage induction machine having implemented static eccentricity fault. The measured data are compared to the theoretical presumptions and the transient finite element analysis of the measured machine. Measurement and finite element model are carried out for the machine in a perfect technical condition as well and those specify the reference point for the faulty machine

Inductive coupling system for electric scooter wireless charging: electromagnetic design and thermal analysis

The paper deals with construction design and laboratory measurement of magnetic inductive coupling system suitable for electric scooter wireless chargers. It briefly elaborates design process relating to the system configuration, material used for construction and obtained operational conditions. The paper also discusses the thermal behavior of the couplers operating under load and describes fully automatic laboratory equipment for the system experimental testing

Dynamic Inductive Coupling Based Wireless Rotor Monitoring System

The paper presents a new technology and design methodology of dynamic inductive coupling based wireless power transmission intended for the real-time measurement of rotor characteristics of electrical machines. The technology is based on dynamic inductive power transmission using three series-connected receivers on the secondary side. The paper summarizes the key system features and discusses optimization steps to maximize the device efficiency. The technical description includes the design of both coupling elements, and power electronics and explains power transmission and communication principles. The functionality of the proposed system is verified by developed device prototype embedded into 270kW permanent magnets synchronous generator

The experimental investigation of behaviour of expanded polystyrene (EPS)

PING 2019 is organized with the support of funds for specific university research project SVK1-2019-002.Low-strength substrates and anthropogenic soils are always an issue in civil engineering. Based on the soil layer types, several methods could be used to improve the basic/foundation layer however it would be difficult to make sure if the specified requirements are achieved. Nowadays, Expandable Polystyrene (EPS) as a lightweight material found as a substitution for traditional methods like soil replacement, soil mixing, using piles driving and other treatment techniques. This paper will demonstrate the static properties of EPS foams in a view point of construction material which will be a key for the future study of these materials. A series of compression tests were carried out on different types of EPS foam to study the effect of EPS geofoam density on the mechanical behaviour of these materials