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Precise LED lamps dimming for stage technology
Šojdr, Marek ; Šteffan, Pavel (referee) ; Levek, Vladimír (advisor)
This bachelor´s thesis discusses the problems of dimming of LED bulbs using DC voltage. It explains basic converters topologies and power factor correction options. Part of the thesis deals with the subharmonic oscillation and possibilities of its elimination. Describes the design of the circuitry of dimmer module for precise dimming of selected types of LED bulbs, revival and testing of the dimmer module. Part of the work is basic for realization of the dimmer (printed circuit board, list of components).
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The reactive-power compensation of the industrial consumer
Mišinger, Ondřej ; Bok, Jaromír (referee) ; Toman, Petr (advisor)
The work deals with reactive-power compensation (power factor correction = PFC) at low and medium voltage. The theoretical part is focused on explaining the basic concepts of power factor correction and the reasons why the PFC is made. There is stated the basic allocation of PFC. Attention is devoted mainly for detuned PFC, which is nowadays often used because of the large number of nonlinear loads installed by customers. There are listed also the basic computational relations. Moreover, there are described the basic elements of compensation devices, which are capacitors, detuning reactors, contactors and power factor regulators. The practical part is dealt with power factor compensation for a particular industrial customers. There are offered several variants of the technical implementation of the PFC. These various options are compared from both technical and economic terms.
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DC-DC converter for onboard charging of electric vehicles
Holub, Miroslav ; Červinka, Dalibor (referee) ; Folprecht, Martin (advisor)
This master thesis deals with design of DC-DC converter for onboard charging of electric vehicle. Developed converter will mainly be used for charging stationary traction battery in laboratory. Output voltage of this charger will be adjustable by user in between 200 V and 450 V depending on the current charged battery configuration. Output current limit is set at 8 A. Since the converter will be supplied from standard household socket, the problem of power factor correction must be solved during the design. That is because a large part of this thesis is focused on describing the problematics of power factor correction. After that, active PFC module is designed, completed and performance of this module is verified. To achieve low overall losses and thus be able to keep small volume of the system, modern switching components based on Silicon Carbide were preferred. Beside laboratory use, completed system will be used to emphasize volumetric difference between onboard chargers based on old versus modern switching components.
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The system of load matching to the energy converter
Halama, Petr ; Mandlík, Michal (referee) ; Drexler, Petr (advisor)
This master’s thesis deals with energy harvesting from the mechanical energy sources. The mechanical energy may be converted into the electrical by means of a vibrational microgenerator. The thesis deals also with the production of energy from different renewable sources. There have been identified conditions for effective transformation of the remaining energy. In order to satisfy these conditions a circuit for load matching to energy harvester has to be used. Four variants of matching circuit have been designed and analyzed in PSpice or LTspice. It has been designed a system of power factor correction controlled by circuit with discrete components and also by microcontroller. For one of these variants a specific integrated circuit has been used. The designed circuits have been built and their parameters haven been determined by measurement.
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Functional model of a small hydro power plant control unit
Rusnák, František ; Arm, Jakub (referee) ; Benešl, Tomáš (advisor)
This semester work deals with realization of functional model of control unit for hydroelectric power station. Main task of this work is realization rectifier with active power factor correction, which is used instead of commonly used frequency converter. Control unit is designed for asynchronous motor in generator operation with self-excitation. The propeller turbine is used as propulsion. Theoretical part includes theory of the PFC converters. Practical part includes calculations for components of PFC converter and assembly of DPS PFC converter.
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Power factor correction and low-frequency conducted disturbances assessment of an industrial induction heating system
Vývoda, Marek ; Žila, Drahoslav (referee) ; Drápela, Jiří (advisor)
This Diploma thesis deals with design of for power factor correction device for mid-frequency-range induction heating and also with assessment of correction device influence in harmonically distorted environment from the distribution net point of view. Research chapters contain of main characteristics of electrical power quality and theoretical background of reactive power, which is in our case caused by driven non-linear elements. Further, the heating power supply block is explained and simulations of power consumption in Matlab - Simulink is done, within the prove of corrective tools design. After the build of corrective tool assemblies, measurements are matched with the simulation results.
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Reactive power compensation systems
Lakomý, Marek ; Paar, Martin (referee) ; Drápela, Jiří (advisor)
Bachelor‘s thesis deals with the compensation of reactive power, which enables improved power factor correction. The theoretical part includes an explanation of basic concepts of the theory of reactive power compensation, the basic allocation of compensating equipment, their description and basic computational relations. Simulation of compensation devices, making laboratory models and measuring their parameters were realized as the practical part of the thesis.
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Ultra low noise switching power supply
Raba, Jaroslav ; Leuchter,, Jan (referee) ; Šrámek, Petr (advisor)
This thesis deals with the issue of switching power supply in terms of noise ratios in the output voltage. In the theoretical part analyzes the basic principle of classical and resonant topology switching power converters in terms of output voltage ripple and switching noise. There are also some possibilities of compensation to minimize switching noise and output ripple. The second part describes the custom design a low noise switching power supply, which is composed of an active power factor corrector, power converters and ripple limiter. The main power converter is designed as an LLC resonant converter. The last part deals with the actual construction of the proposed source, its measurement and presentation of the results.
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