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Measurement of Non-Linear Properties of Loudspeakers
Friml, Vilém ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This thesis deals with calculation of THD dependency on signal frequency and calculation of Rub & buzz distortion using MATLAB software. Thesis includes generation of signals suited for THD measurement, playback and recording using sound card and APx series 500 device. The APx device controlling and data acquisition by MATLAB is also addressed. Loudspeaker electric model is discussed for the use of Rub & buzz measurement.
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Development of voltage instrument transformer resistible against higher harmonics
Mihályi, Róbert ; Odehnal, Martin (referee) ; Bušov, Bohuslav (advisor)
This bachelor's thesis describes the basic principles of transformer operation in the first part. The following chapters focus on issue of higher harmonic frequencies. Then it describes the basic design and principles of instrument transformers, which are the main subject of this work. At present, higher harmonic frequencies are becoming more and more common in electrical networks. Therefore, this work tries to bring new knowledge in the issue of higher harmonic frequencies in instrument transformers. The last chapters describe the computational design of an instrument transformer that resists higher harmonic frequencies. This transformer must be able to transfer these frequencies to the secondary winding. It was necessary to study the standards and technical literature related to this topic in order to create the proposal.
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Modeling of torque-speed characteristics of induction motor
Michalík, Marek ; Chrobák, Petr (referee) ; Vítek, Ondřej (advisor)
This master thesis deals in first part with basic theory of an induction motor and principle of function. It also includes theory about higher harmonics of magnetic field and how asynchronous and synchronous torques are created. Various ways how to decrease effect of these torques are suggested. These findings are later applied in practical analytical calculation in second part, in which all parameters of motor are calculated from given dimensions of motor from technical documentation. This is done for basic and higher harmonics. After that a model of this motor was created in RMxprt program, which also calculated all parameters of this motor and created torque characteristic. This motor was also modelled in ANSYS Maxwell 2D. Additional simulations for finding out influence of harmonics on torque characteristic were also done in this software. Torque characteristic of motor was also practically measured in laboratory. All results were compared and evaluated.
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On Harmonic Content of the Wake Behind a Circular Cylinder
Uruba, Václav ; Procházka, Pavel P.
The wake behind cylinder of circular cross-section is subjected to detailed analysis from the point of view harmonic content. The basic, fundamental frequency could be linked to well-known Bénard-von Kámán vortex street, it is called Strouhal frequency very often. However higher harmonics of 2nd and 3rd order have been detected, as well as important inharmonic partials. The topologies of the velocity flow-field corresponding to the harmonic is to be shown.
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Development of voltage instrument transformer resistible against higher harmonics
Mihályi, Róbert ; Odehnal, Martin (referee) ; Bušov, Bohuslav (advisor)
This bachelor's thesis describes the basic principles of transformer operation in the first part. The following chapters focus on issue of higher harmonic frequencies. Then it describes the basic design and principles of instrument transformers, which are the main subject of this work. At present, higher harmonic frequencies are becoming more and more common in electrical networks. Therefore, this work tries to bring new knowledge in the issue of higher harmonic frequencies in instrument transformers. The last chapters describe the computational design of an instrument transformer that resists higher harmonic frequencies. This transformer must be able to transfer these frequencies to the secondary winding. It was necessary to study the standards and technical literature related to this topic in order to create the proposal.
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Measurement of Non-Linear Properties of Loudspeakers
Friml, Vilém ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This thesis deals with calculation of THD dependency on signal frequency and calculation of Rub & buzz distortion using MATLAB software. Thesis includes generation of signals suited for THD measurement, playback and recording using sound card and APx series 500 device. The APx device controlling and data acquisition by MATLAB is also addressed. Loudspeaker electric model is discussed for the use of Rub & buzz measurement.
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Palaser Project - Back Effect of AFE Converter on Supply Grid Voltage.
Kokeš, Petr ; Adam, Z.
An input device of the Invert 7L frequency converter is the PWM rectifier, also called the AFE (Active Front End) converter. Higher harmonic voltages increase in the medium-voltage supply grid due to AFE operation. The report deals with the calculations and possibilities of reduction of these harmonics. Theoretical results are verified by numerical simulations and compared with measurements on a physical industrial installation.
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Modeling of torque-speed characteristics of induction motor
Michalík, Marek ; Chrobák, Petr (referee) ; Vítek, Ondřej (advisor)
This master thesis deals in first part with basic theory of an induction motor and principle of function. It also includes theory about higher harmonics of magnetic field and how asynchronous and synchronous torques are created. Various ways how to decrease effect of these torques are suggested. These findings are later applied in practical analytical calculation in second part, in which all parameters of motor are calculated from given dimensions of motor from technical documentation. This is done for basic and higher harmonics. After that a model of this motor was created in RMxprt program, which also calculated all parameters of this motor and created torque characteristic. This motor was also modelled in ANSYS Maxwell 2D. Additional simulations for finding out influence of harmonics on torque characteristic were also done in this software. Torque characteristic of motor was also practically measured in laboratory. All results were compared and evaluated.
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