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Simple Models of EMI Filters
Kostrhún, Lukáš ; Urbanec, Tomáš (referee) ; Dřínovský, Jiří (advisor)
Thesis goal was principles and method insertion Loss Measurement of EMI Filters study in harmony with the technical standard ČSN CISPR 17, theoretical insertion Loss of Filters deduce in symmetrical and asymmetrical connection of impedance system 50 ohms /50 ohms, 0.1 ohms /100 ohms and 1 ohm /100 ohms, and opposite, and with measure values of Filters compare.
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RF power meter
Hlaváč, Štěpán ; Jedlička,, Petr (referee) ; Drexler, Petr (advisor)
This master’s thesis describes various principles of measurement of electromagnetic waves in a free space and on a line. Used sensors and their real parameters are given for every method. The analysis of protections of high-frequency inputs of measuring instruments is done here and the most suitable method and protections of input for realization are chosen. The analysis of design of secondary protection of high-frequency input is done in this project. The protection of input is realized and measured. The suitable method of measurement is chosen as well as the sensor for measurement of power. The block diagram and circuit diagram of the meter of power are designed. According to designed conception the measuring instrument for measurement of power is realized and its single qualities are measured during the realization. In the final part its precision is measured and the evaluation of results is done.
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Optimization of EMI filter Circuitry
Surovec, Vojtěch ; Soldán, Josef (referee) ; Dřínovský, Jiří (advisor)
In introduction of work, I presented the state of the art of measuring insertion loss of the EMI filter and the description of individual methods of measuring is also included. After that I dealt with global optimization methods and some of them I theoretically described. Mainly PSO method was studied carefully, and the principle of optimization in details are presented in the thesis, because this method was used for optimization of the filters parameters in the thesis. Next part of work deals with theoretical and mathematical expression of insertion loss of the EMI filters. Due to the mathematical expression of the insertion loss, the values of parasitic elements of given filter have been optimized in different measuring systems. This optimization was applied on synthetic data. By this step the functionality of optimization was proved and also the fitness function has been tuned and optimised. The last part of thesis works with optimization on measured data of given filters. I found out inaccuracy in mathematical expression of given model of EMI filter, therefore it was necessary to come up with the new filter model. The accuracy increases by using the new filter model. In next step the new model was enlarged by new spurious components.
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Models of EMC filters
Kejík, Zdeněk ; Šebesta, Jiří (referee) ; Dřínovský, Jiří (advisor)
Basic problems of the EMI mains filter is explained in the introduction of this thesis. These problems appear during the measurement of insertion loss of filters and by design of EMI mains filter. The important problem is uncertainly of the terminating impedances. Eventualities measurement insertion loss of EMI mains filter and motivation of creation filter models are shown. The following part of this project shows the electronic components, from which are realized the EMI mains filter. Parasitic properties of these real devices are also discussed. The circuitry of EMI mains filter is described by the Modified Nodal Voltage Method. The optimization method called Participle Swarm Optimization is introduced, too. Basic principle and terminology are mentioned. The third part of this project is focused on the own filter and spurious components. Influence of own filter and spurious filters components on insertion loss curve are showed. Magnetic factor coefficient k is searched by the optimization method PSO. The last part of this thesis deals with creation of the alternative circuits with spurious filters components. The performances of the alternative circuits were compared with the measured data for symmetrical and asymmetrical measurement setup. The breakages in the insertion loss curve were used for determining the spurious components.
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Measurement of three-phase EMC filters
Tomašák, Lukáš ; Soldán, Josef (referee) ; Dřínovský, Jiří (advisor)
The aim of this semestral project was to propose the measuring system for measuring three-phase EMI filters in symmetrical, asymmetrical and non-symmetrical mode according to information from supplier of the filters. The major part of this project was focused on measuring the frequency dependence of the insertion loss of three-phase EMI filters in impedance systems 50?/50?, 0,1?/100 ? and 100?/0,1?. It was determined that results approximately agree with specifications in datasheets.
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Impedance Transformers with Impedance Ratio 1/50 Ohms for Wide Frequency Range
Zachar, Jiří ; Šebesta, Jiří (referee) ; Dřínovský, Jiří (advisor)
One of the aims of this bachelor’s project was to explore possibilities of the design of impedance transformers for a very wide frequency bandwidth (10 Hz – 100 MHz) with the impedance ratio 1/50 . It is not possible to cover this wide frequency band by one transformer, so the design was split into the design of two impedance transformers. The first transformer was realized on the ferrite coil RIK20. The second transformer was realized by with the components T16-1 and TT25-1-kk+ produced by Mini-CircuitsŽ company, and transform impedance directly in a high frequency range. The performance of realized transformers was approved by measuring transformed impedance on their outputs. The frequency band of transformers was determined from these data. Their insertion loss was also measured. The last part of this work was focused on measuring the insertion loss of EMI filters. The main task was to compare the impedance systems 1 /100 and 0,1 /100 and vice versa. The insertion loss was measured for several chosen EMI filters. The insertion loss of all filters reached approximately the same values for both impedance systems.
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