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Optimisation of electric vehicles gearbox housing with focus on emitted noise
Fürich, Adam ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This thesis deals with the vibration and noise of the gearbox for an electric vehicle. The gearbox itself acts as an emitter of unwanted noise caused by vibration excitation of the internal components of the gearbox. It is therefore necessary to deal with a complex unit such as the gearbox at system level as soon as it is being designed. This can be achieved using analytical tools and software. In this thesis, in order to evaluate the validity of the designed gearbox, a procedure is developed using both technical experiment and numerical simulations. The effect of the bolt preload is not overlooked for the following computational modelling dealing with the radiated noise of the gearbox. The results obtained from the performed technical experiments were then evaluated and compared with the results of the computational models. In this way, it is possible to compare the different approaches, their limitations and weaknesses. Furthermore, the thesis deals with design modifications that are analyzed using computational modeling. The thesis is concluded with a brief description of the application of each approach and an evaluation of the gearbox design modifications.
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Compensation of Nonlinearities in AC Motor Control Algorithms
Buchta, Luděk ; Kuchař,, Martin (referee) ; Glasberger,, Tomáš (referee) ; Blaha, Petr (advisor)
Analysis of the dead-time effect and other nonlinearities of the voltage source inverter was carried out in the introduction of the doctoral thesis. Three compensation strategies for vector controlled PMSM were proposed based on the analysis. The voltage disturbance observer with cost function of current errors is based on the model of PMSM, known machine parameters and easily measurable quantities. The second observer which estimates the dq- axes currents and the value of the voltage error with one parameter only is designed based on the harmonic analysis and Kalman filter algorithm. The third method combines an adaptive approach with feedback and voltage disturbance observer that is based on the PMSM model. Furthermore, the two compensation methods for vector controlled induction motor were proposed. In the first case, the standard compensation strategy is extended by a harmonic compensator that suppresses the residual 6th harmonic component in dq- axes currents. The last strategy detects the polarity of the estimated phase currents that are obtained by the Kalman filter. All compensation strategies have been verified by MATLAB/Simulink simulations and by experiments on real drives.
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Study of Power Plant Connection to Power Network
Sýkora, Martin ; Kurfűrst, Jiří (referee) ; Paar, Martin (advisor)
It is necessary to judge the influences of producers on the electric compounds while creating electrical energy or during the regulation of those existing. These analyses are sorted out by so called studies of connectivity. These calculations analyze the degree of connection of the producer and the standby unit during a break-down. The results of this report are several recommendations for creating such unit and succeeding steps leading to secure the stability and safety of the electric compound operation. The aim of this thesis is to discuss about software for PC solutions for static and dynamic network model, to draft power outlet into a network of generating high voltage, to complete a study of connectivity with respect to all the distortion factor, as increased voltage, inrush current at startup, flicker, harmonic currents, interference ripple, contribution to short-circuit current, reactive power control options, and demands for compensation.
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Characterisation of the Physical Chemical Processes Using the Fractal and Harmonic Analysis
Haderka, Jan ; Nešpůrek, Stanislav (referee) ; Mikula,, Milan (referee) ; Zmeškal, Oldřich (advisor)
Existuje mnoho různých způsobů jak analyzovat disperzní systémy a fyzikálně chemické processy ke kterým v takových systémech dochází. Tato práce byla zaměřena na charakterizaci těchto procesů pomocí metod harmonické fraktální analýzy. Obrazová data sledovaných systémů byly analyzovány pomocí waveletové analýzy. V průběhu práce byly navrženy různé optimalizace samotné analýzy, převážně zaměřené na odstranění manuálních operací během analýzy a tyto optimalizace byly také inkorporovány do softérového vybavení pro Harmonickou Fraktální Analýzu HarFA, který je vyvíjen na Fakultě chemické, VUT Brno.
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Modeling of thin-walled frames mechatronic systems with fillet welds and their influence on the natural frequency
Appel, Martin ; Hadaš, Zdeněk (referee) ; Vosynek, Petr (advisor)
This bachelor thesis is focused on methods of reduction degrees of freedom and their application in mechatronical system. Next part is focused on fillet welds and their modelling in Ansys Workbench software. Individual possibilities of geometry of welds are analysed by modal, static and harmonic analysis. Aim of this thesis is comparison of results of analysis for different methods of geometry of welds. Then it compare results of modal analysis in Ansys Workbench and Adams software. Finally the work deals with possibilities of exporting from Ansys Workbench to Adams, Matlab and Excel software.
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Determination of Turbocharger Rotor Dynamic Properties
Blaha, Adam ; Zubík, Martin (referee) ; Novotný, Pavel (advisor)
This diploma thesis deals with dynamic behaviour of a turbocharger rotor. The subject is a stock turbocharger for commercial vehicles. The research will be mentioned in the first part of the thesis as well as methods of processing. The second, practical part is divided into two divisions. They are both experimental and computational. The aim is finding of rotordynamic behaviour by an experiment and its comparing with a computational model in ANSYS software. Modal and harmonic analysis of a free and fixed subject will be used by both experiment and evaluation. The subject will be fixed where bearings are located during harmonic analysis. All the experimental results will be processed with mathematical and physical methods like FFT analysis or Campbel diagram. There will be two main types of computational models to choose among. These models will be analyzed in detail. The goal of the thesis is to reach results from ANSYS as close as possible with the experimental testing. This includes finding correct material and physical properties, right choice of mesh and right boundary conditions. At the same time the CPU time compared to the model complexity and results accuracy will be considered in a comparison with data obtained by the experiment.
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An assessment of a bridge construction on a dynamic load
Součková, Markéta ; Kala, Jiří (referee) ; Salajka, Vlastislav (advisor)
Diploma thesis deas with static and dynamic analysis of a steel arch footbridge. The footbridge structure 3D model was created in program ANSYS 12.1 and afterwards were made static and modal analysis on this computational model. Based on the results of~modal analysis was applied to design of dynamic wind loading on the model according to norms ČSN EN. The effects of this burden has been calculated steady response at resonance from harmonic analysis according to ČSN P EN 1991-2-4. To report according to ČSN EN 1991-1-4 was designed substitute quasistatic forces corresponding loads of wind on the construction and for evaluation was used static analysis.
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Strength Analysis of Alternator Body
Kratochvíl, Petr ; Vopařil, Jan (referee) ; Novotný, Pavel (advisor)
In this diploma thesis is theoretically described and then practically performed stress analysis of alternator body, which in terms of traffic racing car often passes into disrepair. It is used reverse engineering method. The real part is converted to digital model and analysed using FEM calculation. Incoming data for FEM are obtained by experimental measurement on the car.
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Remote measuring systems and its utilization in practise
Kukla, Zdeněk ; Škoda, Jan (referee) ; Baxant, Petr (advisor)
This master’s thesis is dealing with remote measuring systems and their utilization in power engineering. In the first part there are described requirements on an autonomous measuring system and description of AMM and AMR systems. Communicating and data flows working on accurately defined communicating layers are also depicted in this part. The attention is devoted to the possibility of data processing and functions of devices offered by these attributes. In the following part there are described reasons for utilization of remote measuring systems in power engineering and the main advantages of connection of more devices into one unit. After finding of required parametres and functions of systems, a suggestion of terminal device is created in the same way. The suggestion is described in the measuring part with A/D converter, processing in microprocessor, measuring and evaluating alogorithms and attributes of communication of bus used. The last part is devoted to utilization of remote analysis in small power stations in dispersed production. Formation of deformation of voltage, harmonic analysis of signal and its application for data processing are described there. Described analysis was tested on data acquired from a cogeneration unit.
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