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Analysis of Current Higher Harmonics Impact on Losses in Transformer Foil Winding
Žďárský, Jan ; Klíma, Petr (referee) ; Mrajca, Miroslav (advisor)
This paper deals with the analysis of the effects of non-sinusoidal current on the foil windings of power transformers. This issue is important in transformer design since losses are measured only when sinusoidal current is passed through. In some applications, these losses need to be recalculated to account for the effect of higher harmonics of the current in actual operation, as these losses are related to transformer heating. A literature search of available sources that have already described this issue is performed in this work. In this paper, a model for simulation in Ansys Maxwell environment is presented, using which the losses due to higher harmonics will be calculated.
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Optimization of the permanent magnet machine based on the artificial inteligence
Kurfűrst, Jiří ; Duroň,, Jiří (referee) ; Singule, Vladislav (referee) ; Ondrůšek, Čestmír (advisor)
The dissertation thesis deal with the design and the optimization of the permanent magnet synchronous machine (SMPM) based on the artificial intelligence. The main target is to apply potential optimization methods on the design procedure of the machine and evaluate the effectiveness of optimization and the optimization usefulness. In general, the optimization of the material properties (NdFeB or SmCo), the efficiency maximization with given nominal input parameters, the cogging torque elimination are proposed. Moreover, the magnet shape optimization, shape of the air gap and the shape of slots were also performed. The well known Genetic algorithm and Self-Organizing migrating algorithm produced in Czech were presented and applied on the particular optimization issues. The basic principles (iterations) and definitions (penalty function and cost function) of proposed algorithms are demonstrated on the examples. The results of the vibration generator optimization (VG) with given power 7mW (0.1g acceleration) and the results of the SMPM 1,1kW (6 krpm) optimization are practically evaluated in the collaboration with industry. Proposed methods are useful for the optimization of PM machines and they are further theoretically applied on the low speed machine (10 krpm) optimization and high speed machine (120 krpm) optimization.
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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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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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Optimization of the permanent magnet machine based on the artificial inteligence
Kurfűrst, Jiří ; Duroň,, Jiří (referee) ; Singule, Vladislav (referee) ; Ondrůšek, Čestmír (advisor)
The dissertation thesis deal with the design and the optimization of the permanent magnet synchronous machine (SMPM) based on the artificial intelligence. The main target is to apply potential optimization methods on the design procedure of the machine and evaluate the effectiveness of optimization and the optimization usefulness. In general, the optimization of the material properties (NdFeB or SmCo), the efficiency maximization with given nominal input parameters, the cogging torque elimination are proposed. Moreover, the magnet shape optimization, shape of the air gap and the shape of slots were also performed. The well known Genetic algorithm and Self-Organizing migrating algorithm produced in Czech were presented and applied on the particular optimization issues. The basic principles (iterations) and definitions (penalty function and cost function) of proposed algorithms are demonstrated on the examples. The results of the vibration generator optimization (VG) with given power 7mW (0.1g acceleration) and the results of the SMPM 1,1kW (6 krpm) optimization are practically evaluated in the collaboration with industry. Proposed methods are useful for the optimization of PM machines and they are further theoretically applied on the low speed machine (10 krpm) optimization and high speed machine (120 krpm) optimization.
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