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Resonant and quasi-resonant converters
Krška, Vlastimil ; Sedláček, Jiří (referee) ; Murina, Milan (advisor)
Project is engaged in concept and realization of quasi – resonant converter with switching in minimum voltage which derive benefit from resonance capacitor and inductor. It is one of the possibilities how to increase efficiency of switch – mode power supply. While using resonant converters the losses are reduced, when the resonant inductor will connect and disconnect at zero current in inductor, or at zero voltage on inductor. Base of the power supply is chip NCP1337. Concept comes from detailed analysis functions of integrated curcuit and others curcuits of switch – mode power supply. Project includes a complete concept of all partial curcuits, description of a construction and the main parameters measured on the realized sample.
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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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Resonant and quasi-resonant converters
Krška, Vlastimil ; Sedláček, Jiří (referee) ; Murina, Milan (advisor)
Project is engaged in concept and realization of quasi – resonant converter with switching in minimum voltage which derive benefit from resonance capacitor and inductor. It is one of the possibilities how to increase efficiency of switch – mode power supply. While using resonant converters the losses are reduced, when the resonant inductor will connect and disconnect at zero current in inductor, or at zero voltage on inductor. Base of the power supply is chip NCP1337. Concept comes from detailed analysis functions of integrated curcuit and others curcuits of switch – mode power supply. Project includes a complete concept of all partial curcuits, description of a construction and the main parameters measured on the realized sample.
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|
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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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