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Impedance measurement of lead-acid accumulator properties
Vaculík, Sebastian ; Neoral, Jiří (referee) ; Abraham, Pavel (advisor)
This work deals with the new and unique four-point method measurement of the impedance characteristics for experimental positive electrode. The theoretical part provides a short introduction to the electrochemical power sources, including the lead-acid batteries, which were used for measurement. Furthermore, there is description of the principle of electrochemical impedance spectroscopy and analysis of obtained data by using the equivalent circuit, consisting of passive components. The experimental section is devoted to the description of the device, which is used for realization of connection of electrodes with Potenciostat VSP, and program which is used for the simplification of processing of results. The main aim of this bachelor thesis is to get better understanding of lead-acid accumulators and impedance measurements. At practical part of the thesis I performed first measurements by two-step method based on electrochemical impedance spectroscopy.
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Parameter analysis of induction motor equivalent circuits
Minks, Ondřej ; Běloušek, Radim (referee) ; Mach, Martin (advisor)
This work deals with the determination of the parameters of induction motor equivalent circuits in T-network, gamma-network and inverted gamma-network form from no-load test and discovering voltage dependence of these parameters. For each of these circuits are determined dependencies of the torque and the stator current on the slip. Using the MATLAB simulations, the theoretically derived dependencies are compared with real, which are measured on the motor with the squirrel-cage rotor with power 0,6 kW, 2p = 2, both in operating and in whole motor area.
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Analysis of different types of the induction machine substituting circuit.
Halfar, Lukáš ; Vašíček, Adam (referee) ; Běloušek, Radim (advisor)
The bachelor´s thesis is focused on equivalet circuits of the asynchronous motor. From the topological point of view, we can divide the equivalent circuits into T-network, -network and -network. Each of these circuits has its use. In the thesis are derived all of networks and are described their properties. Their use is deduced from properties. Next part is devoted to derivate reversible formulas between T-network and -network, T-network and -network. The thesis also include derivation of torque characteristic. The practical part is devoted to measuring of asynchronous motor AOM090L02-16 to identify parameters of equivalent circuit. The identification of the parameters is performed by two different methods of identification. The methods are compared by use in formula of torque characteristic. The last part is dedicated to comparison of usefulness of individual equivalent circuits.
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Mechanical Torque Analysis of Induction Machine Based on Magnetic Circuit Saturation
Skalka, Miroslav ; Bendl,, Jiří (referee) ; Voženílek, Petr (referee) ; Ondrůšek, Čestmír (advisor)
e main goal of this thesis is mechanical torque analysis of induction machine based on magnetic circuit saturation, oversaturated areas classification and the possibility of oversaturated areas reduction of their influence on machine properties. Whole problem is solved by finite element method in ANSYS program. Work is divided into the description and creating of electromagnetic model, a method of the induction machine equivalent circuit parameters determination, the electromagnetic field calculation by finite element method, experimental measurement using LabVIEW program with measurement accessories (PCIe card National Instruments), data processing program in DIAdem, results analysis of calculations in terms of magnetic circuit saturation, the influence of magnetic circuit material based on electromagnetic field distribution and the magnetic flux density along the air gap including spectral analysis using MATLAB and the electromagnetic torque and its parasitic torque components calculation.
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Parameter Identification of Induction Motor Equivalent Circuits
Karpenko, Oleksii ; Cipín, Radoslav (referee) ; Toman, Marek (advisor)
In the control of an asynchronous motor, it is important to determine the parameters of its replacement connection with the greatest accuracy. This work focuses on the identification of these parameters by various methods, which are represented in the form of a -network and a T-network. The bachelor thesis is divided into five parts. The first part focuses on the theory of the asynchronous motor, its use, distribution and properties. The second part deals with replacement connections of the asynchronous motor, their specifics and the possibility of its conversion. The third chapter focuses on the theoretical procedures of parameter identification using various methods as well as the theory of engine tests. In the last two chapters, the theoretical findings from the previous parts are experimentally verified on a real engine sample. Subsequently, the results obtained by different methods were compared with each other.
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Impedance spectroscopy characterization of perovskite solar cell materials
Křečková, Jitka ; Vanýsek, Petr (referee) ; Novák, Vítězslav (advisor)
The Master‘s thesis deals with the topic of perovskite solar cells with the main focus on the materials used for the active layer. In the introductory part, the electrical and optical properties of halide perovskites are described and specific examples of perovskite crystals are introduced. The description of impedance and photoimpedance measurement methods used for characterization of perovskite solar cells is also included in the thesis. The measurement of electrochemical impedance spectroscopy was conducted on four perovskite crystals and equivalent circuit was formed to fit the obtained data. Parameters of the circuit elements were acquired using the fitting method and were further evaluated in experimental part of this thesis.
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Optimization of magnetic circuit of induction motor for frequency up to 210 Hz
Binek, Martin ; Cipín, Radoslav (referee) ; Vítek, Ondřej (advisor)
This master’s thesis first deals with the theory concerning induction motor. It briefly desbribes the construction of three-phase induction motors, the generation of tractive force, power flow with loss distribution and also torque characteristic. In the next part an analytical calculation of the parameters of equivalent circuit for an existing induction motor with known dimensions is performed. After the calculation it is possible to find out the rated parameters of the motor, which makes it possible to further compare results with the values obtained by other methods. The next step was to create a model of the motor in RMxprt program, which is later also translated to ANSYS Maxwell 2D model. Simulations were carried out in both interfaces. As the next step the results obtained by the three methods are compared with measured values and also evaluated. The final part of the thesis focuses on the optimization of the magnetic circuit for higher frequencies. Efficiency of the modified induction motor is examined for higher frequencies using RMxprt Optimetrics and this procedure is performed for both default and alternative electrical steel materials.
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Operation of induction motor with respect to maximum efficiency
Čech, Jiří ; Ctibor, Jiří (referee) ; Toman, Marek (advisor)
In the first part of this paper a mathematical model of induction motor is described. With usage of -network equivalent circuit equations for calculation of individual power losses and overall efficiency are derived. Research study of loss minimization control is introduced in the next part. Several often used methods of variable frequency drive control are described. Also a review of loss minimization techniques from the perspective of induction motor control are presented. The last part of this paper includes a detailed description of scalar induction motor drive focused on reaching optimal efficiency. The loss minimization technique used is a model based method with rotor frequency being the control variable. At the end the performance of this method is verified using a computational script in Matlab.
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Analysis of different types of the induction machine substituting circuit.
Halfar, Lukáš ; Vašíček, Adam (referee) ; Běloušek, Radim (advisor)
The bachelor´s thesis is focused on equivalet circuits of the asynchronous motor. From the topological point of view, we can divide the equivalent circuits into T-network, -network and -network. Each of these circuits has its use. In the thesis are derived all of networks and are described their properties. Their use is deduced from properties. Next part is devoted to derivate reversible formulas between T-network and -network, T-network and -network. The thesis also include derivation of torque characteristic. The practical part is devoted to measuring of asynchronous motor AOM090L02-16 to identify parameters of equivalent circuit. The identification of the parameters is performed by two different methods of identification. The methods are compared by use in formula of torque characteristic. The last part is dedicated to comparison of usefulness of individual equivalent circuits.
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Parameter analysis of induction motor equivalent circuits
Minks, Ondřej ; Běloušek, Radim (referee) ; Mach, Martin (advisor)
This work deals with the determination of the parameters of induction motor equivalent circuits in T-network, gamma-network and inverted gamma-network form from no-load test and discovering voltage dependence of these parameters. For each of these circuits are determined dependencies of the torque and the stator current on the slip. Using the MATLAB simulations, the theoretically derived dependencies are compared with real, which are measured on the motor with the squirrel-cage rotor with power 0,6 kW, 2p = 2, both in operating and in whole motor area.
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