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National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
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.
Detailed record
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.
Detailed record

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