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Losses in induction machines supplied by a frequency converter
Lípa, Miroslav ; Vítek, Ondřej (referee) ; Bárta, Jan (advisor)
Diplomová práce se zabývá měřením asynchronního motoru se dvěma různými zdroji napájení, a to s frekvenčním měničem a generátorem. Tyto dva zdroje napájení byly následně simulovány pomocí metody konečných prvků a porovnány. První kapitola se zabývá popisem asynchronního stroje napájeného frekvenčním měničem a také doporučenými úpravami pro tento druh napájení, aby se předešlo co nejvíce nežádoucím jevům. Druhá kapitola se věnuje ztrátám asynchronního stroje. Třetí kapitola popisuje přístup k měření a vyhodnocování harmonických ztrát způsobených napájením z měniče a také standardizovaný přístup podle mezinárodních norem. Druhá polovina třetí kapitoly také popisuje výpočetní analýzu, která je v této práci použita ve formě analýzy konečných prvků. Nakonec jsou popsány nejistoty měření při použití standardní metody vstup-výstup. Ve čtvrté kapitole je představeno modelování v softwaru ANSYS MAXWELL, kde je nejprve popsána tvorba modelu specifikovaného stroje, poté jeho simulace se sinusovým napájením, a v druhé polovině je vysvětlena simulace s PWM napájením a jak bylo PWM replikováno pomocí naměřených průběhů. V páté kapitole jsou prezentovány všechny výsledky měření s vyhodnocením. Na konci kapitoly je uvedeno srovnání simulace a měření a jeho nedostatečná přesnost.
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Back-to-back inverter for motors and generators
Wich, Petr ; Ctibor, Jiří (referee) ; Knobloch, Jan (advisor)
The aim of this thesis was to design and implement a back-to-back converter. It is an indirect frequency converter with a DC intermediate circuit and an active rectifier. First of all design procedure of the individual components is described with the calculation of their operating parameters. Next, the interconnection of the components and the assembly of the inverter including a virtual model is described. Subsequently, a mathematical model of the inverter was created and the control algorithm was tested on it. In the next part, the correctness of analogue value sensing by the control electronics was verified. Finally, test measurements were carried out to verify the operating parameters of the inverter, including verification of the power sizing.
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Experimental workplace of controlled drive with high dynamics
Rozkošný, Miroslav ; Marada, Tomáš (referee) ; Němec, Zdeněk (advisor)
My diploma thesis deals with the basic principle of the frequency inverter and his construnction. In the next section are analyze the basic properties and characteristics of the using equipment. The main part of this thesis is to investigate the dynamic properties of asynchronous electric motor controlled by a frequency inverter using STARTER. The results of experiments are compared and analyzed.
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DC/AC inverter for small asynchronous machine
Pavlík, Ondřej ; Patočka, Miroslav (referee) ; Červinka, Dalibor (advisor)
The aim of this Bachelor thesis is to propose three-phase converter of low power 100W for driving the asynchronous motor. The device is suitable for construction with fans. This proposal was optimized in light of close price and of technical practicability. The arrangement is possible to use in less exacting applications where it was guarded high price of common converters so far. For allocation catalogue scheme were chosen acceptable components and designed the board of printed circuits.
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Motor speed control exhibit with frequency changer
Möhwald, Jiří ; Marada, Tomáš (referee) ; Němec, Zdeněk (advisor)
The following diploma thesis deals with the management of asynchronous motor revolutions by a frequency converter MICROMASTER 440 via the programmable controller S7-200. At the beginning, I researched the company documentation of Siemens, which is the producer of the frequency converter and the programmable controller mentioned above. As my work proceeded, I also started to study the company documentation of Mitsubishi Electric, which produces the operating pannel. The first part of my thesis provides a general description of the stated devices and the second part deals with the solution of the task itself. My task was to design a way of communication between the converter and the controller. I chose a USS protocol via serial port RS-485. The operation of the controller was performed by using an operating terminal type GOT1000 which was connected to the controller. In summary, my diploma thesis primarily deals with the construction of an operating programme for the controller and with creating of a graphical control on the terminal. In the end, I evaluated the knowledge gained during the work on this subject and suggested further procedures.
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Use of standard centrifugal pump as turbine
Podešva, Adam ; Franc, Zdeněk (referee) ; Habán, Vladimír (advisor)
This work deals with the use of a centrifugal pump in turbine mode and control of the system where this machine is operated. The introduction describes and divides the various types of pumps and discusses the issue of Euler's pump and turbine equations. The flow control options are also described here. Part of the work is a research that examines the advantages and disadvantages of using a centrifugal pump in turbine mode, the possibilities of using this system and real applications in the Czech Republic and in the world. The main part is the design of a mathematical model in Microsoft Excel, which solves the regulation of the piping system with a pump operating in turbine mode, especially out of the optimal operating parameters.
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Microprocessor controlled inverter for motors
Fiala, Michal ; Červinka, Dalibor (referee) ; Knobloch, Jan (advisor)
This diploma thesis deals with design of universal converter used for motor control by microcontroller. The first part contains concept, functional overview of the device and its parts. The next part deals with mechanical design and construction of the converter and dimensioning of power, control and measurement circuits. The following part describes control algoritm used for three-phase motor and its testing using simulation. The final chapter of the thesis describes PCB mounting and testing of the device and control algoritm on real motor.
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