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Evaluation of the operating state of asynchronous motors of the Dukovany nuclear power plant by the method of frequency analysis of stator current
Štěpanovský, Libor ; Kasárník, Milan (referee) ; Mastný, Petr (advisor)
The masters thesis is concerned with the setting of limits and criteria, the design of database environment and the evaluation of the current state of motors of the important machines related to own consumption of the Nuclear power plant Dukovany. The first part of the thesis is a short description of induction motors, the evaluation method and the inventory of the observed motors related to own consumption of Nuclear power plant Dukovany. The second part of the thesis concerns the design of limits and criteria for evaluating the current state of these important motors. Finally, the thesis shows a short description of the electro monitoring system together with the description of the database environment created. In the supplementary materials of the thesis, there is a design of a protocol template for evaluation of the current state of the motor and a technical report template for regular evaluation in monitored areas MCSA (Motor Current Signature Analysis) of the state of the induction motors.
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Identification of AC induction motor parameters
Křížek, Tomáš ; Václavek, Pavel (referee) ; Blaha, Petr (advisor)
This thesis describes and realizes (in program Matlab/Simulink and in the microcontroller Freescale 56F8346) one off-line identification method of AC Induction motor parameters which are necessary to implement the field-oriented control strategy. The identification metod identify leakage inductance, magnetizing inductance and secondary time constants. The presented method is evaluted, advantages and disadvantages of this method are evaluated with reference to their possible use in real-machine. The experimental results and schemes which are presented demonstrate the feasibility methods. The thesis is dividend in seven chapters. Second chapter describes the basic principle and model AC induction motor. Third chapter generally describes identification methods. Fourth, fifth and sixth chapters deal with method which is based on a previous work of the authors [4] and [5].
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Study of concentrated winding induction motor
Trn, Ondřej ; Ondrůšek, Čestmír (referee) ; Vítek, Ondřej (advisor)
This diploma thesis deals with the possibility of using a concentrated winding in an induction motor and the use of copper bars in a rotor cage. The first part of the thesis explains the basic theoretical knowledge of the operation and principle of the induction machine. In this theoretical part we will learn what is actually a concentrated winding and how it is placed on the stator. The second part is focused on the analytical design of the machine with classical distributed winding and with concentrated winding. The third theoretical part is an introduction to the issue of influencing the motor harmonics. The last final part of the thesis shows differences in operational properties of designed machines.
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AC Induction Machine Field Weakening Algorithms
Mynář, Zbyněk ; Veselý, Libor (referee) ; Václavek, Pavel (advisor)
Nowadays, thanks to advances in information and power technology induction motors are deployed there, where previously only other types of electric motors were possible to use. Those typically lack the reliability and low cost of induction motors. Best results in control of induction motors are achieved when vector control is used, to which part of the work is paid. If induction motor reaches the speed when it is no longer possible to continue to increase stator voltage, there is possibility of field weakening or reduction of magnetic flux and thus achieve higher speed. A comparison of several algorithms is devoted to this work. As a simulation tool MATLAB-Simulink was used. Another part is devoted to implementation of these algorithms to the processor of 56F800E series which uses calculations in fixed point.
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Mathematical models of the transformers and asynchronous machines
Cipín, Radoslav ; Běloušek, Josef (referee) ; Patočka, Miroslav (advisor)
The fist part of this work is dealt with the construction of the mathematical models of voltage and current transformers. There are created and simulated models of voltage and current transformer with the nonlinear magnetization characteristics. The second part of this work is dealt with equivalent circuit of the induction motor in the form of Gamma-circuit. The speed-torque characteristic and the dependence of stator current on the slip are calculated from this equivalent circuit. The third part of this work is dealt with electromagnetic design of the alternating current machines by the help of a classic way and a new way.
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Small Induction Motors for Specific Applications
Bárta, Jiří ; Janda, Marcel (referee) ; Hájek, Vítězslav (advisor)
The aim of this master`s thesis is to introduce the principle of construction of a single-phase shade-pole motor and its utilization in automotive industry. It is very simple motor in its structure. The position of shading ring gives us the direction of rotation. It is used mainly when low efficiency is needed, e. g. to run electrical fans, small household appliancesor. Cheap construction is its undeniable advantage.
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Impact of rotor on a small induction machine efficiency
Stuchlý, Karel ; Janda, Marcel (referee) ; Mach, Martin (advisor)
The aim of this master thesis is optimization of the rotor in the terms of efficiency. An analysis of the effects of rotor parameters is performed by RMXPRT. A genetic algorithm is created to find the optimal solution. Solutions are evaluated and adjusted according to the results. Measurements on the actual machine are performed and evaluated to verify the functionality of the simulation models.
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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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The influence of the frequency converter on the life and damage of bearings
Sukovatý, Adam ; Krejčí, Petr (referee) ; Nahodil, Petr (advisor)
This thesis deals with the effect of frequency inverter on the lifetime of roller bearings. The measurement has been carried out on the frequency inverter and induction motor by Siemens in the Switchgear laboratory of Fakulty of elektrical engineering and communication. Data has been recorded and processed on Adash VA4 Pro analyzer. Methods of measuring RMS values and frequency analysis of vibration and current were used for the analysis. Based on the mutual similarity of frequency spectrum, the presence of the high frequency capacitive current in the bearings has been proven. To prevent this, possible solutions have been presented. In the second part of the experiment an effect of changing pulse width modulation (PWM) on vibration was examined. The goal was to make a basic analysis and to provide background material for further research.
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Calculation of synchronized induction machine
Bárta, Jan ; Huzlík, Rostislav (referee) ; Ondrůšek, Čestmír (advisor)
The basic idea of this thesis is to explore the possibility of the increasing the efficiency of induction motors via reluctance rotor. The first part briefly describes the electromagnetic fields simulation software Ansoft Maxwell. The thesis is further dealing with the principles of reluctance motors with rotors and their structures. Another chapter desribes the creation and evaluation of the initial model of the induction motor. The last part of the thesis assess the influence on the resulting reluctance rotor machine parameters.
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