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Power Supply System for Housis Using Renewable Resources
Gálus, Matej ; Punčochář, Josef (referee) ; Šebesta, Jiří (advisor)
The aim of this thesis is to describe the advantages of simultaneous utilization of photovoltaic and wind electricity in an autonomous system, supplying the household with electricity without connection to the electrical grid. The most used methods of connecting photovoltaic modules and wind generators to chemical batteries are discussed. Several maximum power point tracking methods and their properties are described. A block schematic diagram of an autonomous off-grid system utilizing chemical accumulators is proposed. The system also contains an inverter producing standard mains voltage 230 VAC to supply common household appliances. A Quasi-Square Wave converter topology was chosen for all three power converters. An experimental 180 W output power QSW converter with one controllable switch was designed, simulated with Pspice, manufactured and tested to verify the efficiency of the topology. Excellent agreement was found between predicted and measured efficiency at full output power. Efficiency for reliable operation varies between 89% and 92,2% at full power and depends mainly power inductor and MOSFET used. After successful evaluation of QSW topology, the power converters for the main system were designed. Because of higher power, the converters were designed as four-phase, whereas each phase contains two controllable switches to boost efficiency mainly in low-power area. The most critical and difficult part of the project was to design the mixed-signal control sections for the converters to ensure proper switching of two controllable MOSFETs in each phase. For user interactivity, main control board with graphic LC display, Ethernet module and SD memory card slot was also manufactured.
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Power Factor Controllers for Switch-Mode Power Supllies
Gálus, Matej ; Steinbauer, Miloslav (referee) ; Murina, Milan (advisor)
The aim of this thesis is to design an active power factor correction (PFC) circuit for correcting a power factor of a switching power supplies. Various possible causes of bad AC mains power factor are discussed. Differences between linear and non-linear loads’ behaviour to AC mains are recognized and discussed. Various passive and active solutions for correcting current displacement and harmonic distortion are reviewed. Boost converter with quasi-resonant switching controlled by Texas Instruments’ UC3855 is chosen for highest total power factor for given power level against other topologies and its high efficiency and lower EMI against traditional boost converter. Various circuit parameters are simulated using PSpice. Complete circuit diagram for an 1kW output power level and worldwide mains voltage compatiblity is designed. After the device prototype was constructed, efficiency measurements were made and measured values are less than expected. This was apparently caused mainly due to absence of saturable reactor and implementation of resistive damping of the quasiresonant circuit’s parasitic resonance. Measured values of power factor are, however, very high and do meet the design expectations.
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Power Factor Controllers for Switch-Mode Power Supllies
Gálus, Matej ; Steinbauer, Miloslav (referee) ; Murina, Milan (advisor)
The aim of this thesis is to design an active power factor correction (PFC) circuit for correcting a power factor of a switching power supplies. Various possible causes of bad AC mains power factor are discussed. Differences between linear and non-linear loads’ behaviour to AC mains are recognized and discussed. Various passive and active solutions for correcting current displacement and harmonic distortion are reviewed. Boost converter with quasi-resonant switching controlled by Texas Instruments’ UC3855 is chosen for highest total power factor for given power level against other topologies and its high efficiency and lower EMI against traditional boost converter. Various circuit parameters are simulated using PSpice. Complete circuit diagram for an 1kW output power level and worldwide mains voltage compatiblity is designed. After the device prototype was constructed, efficiency measurements were made and measured values are less than expected. This was apparently caused mainly due to absence of saturable reactor and implementation of resistive damping of the quasiresonant circuit’s parasitic resonance. Measured values of power factor are, however, very high and do meet the design expectations.
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Power Supply System for Housis Using Renewable Resources
Gálus, Matej ; Punčochář, Josef (referee) ; Šebesta, Jiří (advisor)
The aim of this thesis is to describe the advantages of simultaneous utilization of photovoltaic and wind electricity in an autonomous system, supplying the household with electricity without connection to the electrical grid. The most used methods of connecting photovoltaic modules and wind generators to chemical batteries are discussed. Several maximum power point tracking methods and their properties are described. A block schematic diagram of an autonomous off-grid system utilizing chemical accumulators is proposed. The system also contains an inverter producing standard mains voltage 230 VAC to supply common household appliances. A Quasi-Square Wave converter topology was chosen for all three power converters. An experimental 180 W output power QSW converter with one controllable switch was designed, simulated with Pspice, manufactured and tested to verify the efficiency of the topology. Excellent agreement was found between predicted and measured efficiency at full output power. Efficiency for reliable operation varies between 89% and 92,2% at full power and depends mainly power inductor and MOSFET used. After successful evaluation of QSW topology, the power converters for the main system were designed. Because of higher power, the converters were designed as four-phase, whereas each phase contains two controllable switches to boost efficiency mainly in low-power area. The most critical and difficult part of the project was to design the mixed-signal control sections for the converters to ensure proper switching of two controllable MOSFETs in each phase. For user interactivity, main control board with graphic LC display, Ethernet module and SD memory card slot was also manufactured.
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