National Repository of Grey Literature 97 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Energy Harvesting Power Supply for MEMS Applications
Smilek, Jan ; Leuchter, Jan (referee) ; Ondrůšek, Čestmír (referee) ; Hadaš, Zdeněk (advisor)
Tato práce se zabývá vývojem nezávislého elektrického zdroje pro moderní nízkopříkonové elektrické aplikace. Protože tradiční řešení napájení drobných spotřebičů s využitím baterií či akumulátorů snižuje uživatelský komfort kvůli potřebě pravidelné údržby, navrhovaný zdroj využívá principu energy harvesting. Tento princip spočívá v získávání energie přímo z okolního prostředí napájené aplikace a její přeměně na energii elektrickou, která je dále využita pro na-pájení moderních MEMS (mikroelektromechanických) zařízení. Potenciální aplikací vyvíjeného zdroje je především moderní nositelná elektronika a biomedicínské senzory. Tato oblast využití ovšem klade zvýšené nároky na parametry generátoru, který musí zajistit dostatečný generovaný výkon z energie, dostupné v okolí lidského těla, a to při zachování prakticky využitelné velikosti a hmotnosti. Po stanovení předběžných požadavků a provedení analýz vhodnosti dostupných zdrojů energie ke konverzi byla k využití vybrána kinetická energie lidských aktivit. Byla provedena série měření zrychlení na lidském těle, především v místě předpokládaného umístění generátoru, aby bylo možno analyzovat a generalizovat hodnoty energie dostupné ke konverzi v daném umístění. V návaznosti na tato měření a analýzy byl vyvinut inovativní kinetický energy harvester, který byl následně vyroben jako funkční vzorek. Tento vzorek byl pak testován v reálných podmínkách pro verifikaci simulačního modelu a vyhodnocení reálné použitelnosti takového zařízení. Kromě samotného vývoje generátoru je v práci popsán i originální způsob zvýšení generovaného výkonu pro kinetické energy harvestery a jsou prezentována statistická data a modely pro predikci využitelnosti kinetických harvesterů pro získávání energie z lidské aktivity.
Axial magnetic flux generator for small hydro power plant
Tauš, Michal ; Bulín, Tomáš (referee) ; Ondrůšek, Čestmír (advisor)
This bachelor thesis deals with a design of axial permanent magnet generator. The first part is devoted to the overview of machines driven by permanent magnets and the comparison of axial machines. In the next part the thesis deals with the design of the machine with axial magnetic flux based on the specified parameters. In the last part, the real properties are verified by ANSYS Maxwell simulations.
FEM model and simulation of induction motor with pole-changing winding
Záškodný, Jiří ; Ondrůšek, Čestmír (referee) ; Vítek, Ondřej (advisor)
This master thesis deals with calculations and simulations of multi-speed induction motors. In the first part, basic principle of these machines is described. Next, there are given three examples of pole-changing stator windings and their properties are analyzed (winding factors, magnetomotive force). Main part includes simulations and measuring of the specific motor, which is produced by company Siemens Mohelnice. This is the motor with 2/1 pole-changing in Y/YY connection. First, influence of skewed rotor slots on current and torque is analyzed. Next, parametres of motor from simulations are given and these results are compared to measured values.
Contactless loading and measurement of high-speed machines
Vojče, Zbyněk ; Ondrůšek, Čestmír (referee) ; Vítek, Ondřej (advisor)
Práce se zabývá problematikou měření momentu u velmi vysokootáčkových strojů. Z důvodů vysokých rychlostí jsou tradiční metody měření momentu nepoužitelné, z tohoto důvodu je nutno vyvinout novou bezkontaktní metodu. Pro měření je zvolena metoda zatěžování vířivou brzdou, pro kterou je proveden analytický výpočet jejích vlastností pomocí Maxwellových rovnic a je vytvořen model vířivé brzdy v programu FEMM a Ansys/Maxwell 2D. Na závěr jsou výsledky simulací a výpočtů porovnány s měřením na prototypech brzdy.
Design of rotating rectifier for synchronous generator
Skurka, Tomáš ; Cibulka,, Tomáš (referee) ; Ondrůšek, Čestmír (advisor)
This diploma thesis is focused on the design of a rotating rectifier for a synchronous generator. Based on defined requirements, the new rotating rectifier concept has been created that allows a greater current range than existing rectifier used by Siemens Electric Machines s.r.o. The thesis is divided into five parts. The first part deals with the search of existing rotating rectifiers and other design possibilities. The requirements for the rotating rectifier were defined in the second part of the thesis. The following section deals with both electrical design of rectifier elements and varistors. The fourth part of the diploma thesis describes the thermal analysis. On the basis of thermal analysis the operating conditions of the rotating rectifier were determined. The last part of the thesis is devoted to mechanical and modal analysis. Based on these analyses, the strength and operability of the new rotating rectifier concept were verified.
Drive for seal-less pump
Pruša, Radomír ; Kurfurst,, Ing Jiří (referee) ; Ondrůšek, Čestmír (advisor)
The aim of this thesis is to design a drive for seal-less centrifugal pump. Designed motor with axial magnetic flux is a double-sided structure with an internal coreless stator. The construction of the seal-less pump is based on a patent no. 17818, which was created at the Victor Kaplan Department of Fluid Engineering BUT. Potential use of this assembly is mainly in the food industry, possibly in the field of chemically aggressive liquids. The whole design is based on coordination between analytical equations and finite element method of the software ANSYS Maxwell. The temperature ratios inside the motor were investigated when cooling with air by the iterative solution of thermal circuit. The work includes research on the topic of constructing the axial machines and their applications in pumps. A comprehensive specification of the entire seal-less centrifugal pump is given in Chapter 4.
Design and simulation of interior permanent magnet synchronous machine
Veselý, Petr ; Vlach, Radek (referee) ; Ondrůšek, Čestmír (advisor)
The master’s thesis deals with the design of a synchronous motor with embedded magnets. First of all, the general theory of synchronous motor, which is focused on field-weakening drive, is described. Then a 6-pole and a 8-pole version of the motor with embded magnet, which has 65 kW and 3000 rpm is complexly designed. Motors are compared with each other and with a motor with surface magnets, that was also designed in this work. Finally, all motors are compared with a mafufactured and measured motor.
Indirect torque measurement in the output of load drive
Jelének, Marek ; Cipín, Radoslav (referee) ; Ondrůšek, Čestmír (advisor)
For loading of excavator drive units, it is necessary to use electromechanical loads with a high torque up to 16,000 Nm in a low speed range from 0 to 150 min-1 with a maximum output of 50 kW. The electromechanical load consists of an asynchronous dynamometer assembly with a tilting torque measurement system in conjunction with a front three-speed gearbox. The dynamometer is powered by a converter with vector control. To determine the torque at the gearbox output, a correction must be made and the influence of operating temperature and operating speed must be taken into account. Experimental measurement of these influences and dependencies makes it possible to create a mathematical model that can be implemented in the power converter for torque control at the output of the gearbox. The aim of the master thesis is a brief design of the loading drive, design an implementation of experimental measurement of efficiency maps and evaluation of the influence of inefficiency of gearbox efficiency.
Kogenerační jednotka mikro výkonu v RD
Pusztai, Radek ; Skalka, Miroslav (referee) ; Ondrůšek, Čestmír (advisor)
Bachelor paper on "Cogenerational unit of micro energy in a single-family house" occupies with analysis of usage and economical effectiveness of cogenerational installation in the single-family house. Results and used material are based on longtime knowledge of leading Czech and world companies and institutions. Paper is structed into two parts.
Design of Electrical Machine 6 kW, 120 000 rpm for Helium Turbo-Circulator
Bárta, Jan ; Rafajdus,, Pavol (referee) ; Dušek,, Jiří (referee) ; Ondrůšek, Čestmír (advisor)
The induction machine with a squirrel cage is a workhorse of the industry. The main advantage of an induction machine is the low manufacturing price, simple and robust construction, low maintenance requirements. However, for high-speed applications, induction machine with a squirrel cage requires design modification due to the mechanical restrictions. The objective of this thesis is to show design process, methodology and assembly of the induction machine for high-speed applications. In this thesis, the rotor dimensioning data are presented. The results are demonstrated on the design of the 6 kW, 120 000 rpm solid rotor squirrel cage induction machine. This thesis also contains calculation and design of three different electrical machine topologies for a turbo circulator application. The electrical machines are designed with 6 kW output power at 120 000 rpm. The machines are estimated by using electromagnetic, thermal, and mechanical calculations. The drawbacks and advantages of each topology under study are described. For other high-speed applications, a comparative method helps in choosing the suitable electrical machine topology by examinations of discussed criteria. Rotor design effect on the electromagnetic performance of the induction machine is shown. Mechanical stresses are calculated with Finite Element Method analysis. Various assembly technologies to produce solid rotor with squirrel cage are discuss and compare. Describe approach enables high electromagnetic performance and durable construction of the high-speed induction machine. Work is confirmed by measurement on the manufactured prototype.

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