Browsing by Author "Yu, Sheng-Yang"

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A Comparison Study of Boost and Buck-boost Power Factor Corrector for Ultra-wide Input Voltage Range Applications
(2014-01-01)
Yu, Sheng-Yang
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Chen, Hung-Chi
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電機工程學系
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Department of Electrical and Computer Engineering
Due to the potential need for ultra-wide input voltage range power factor correction (PFC) circuit, one may consider Buck-boost converter as a PFC circuit (PFC Buck-boost) instead of Boost converter (PFC Boost). The voltage step-up/down freedom of Buck-boost converter allows a lower output voltage and smaller duty cycle compared to Boost converter. In addition, indirect input/output path limits the startup inrush current of PFC Buck-boost. Unlike PFC Boost, PFC Buck-boost doesn't need an inrush current limiting circuit, which allows a lower cost PFC circuit by applying Buck-boost converter. This paper conducts a comparison study of PFC Boost and PFC Buck-boost for a two stage system (PFC stage in cascade with an isolated DC-DC converter). Transient mode PFC is selected in this study for low power applications. Two 100W power supply prototypes are made for this comparison. The results show that PFC Buck-boost is able to provide a higher efficiency than PFC Boost under low input voltage with fewer power stage circuit components.
Input Current Control for Bridgeless PFC Converter without Sensing Current
(2014-01-01)
Chen, Hung-Chi
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Chung, Chao-Chiang
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Liao, Jhen-Yu
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Yu, Sheng-Yang
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電機資訊學士班
The bridgeless power-factor-correction (PFC) converter possesses higher efficiency than the conventional boosttype PFC converter due to its reduced conduction voltage drop and conduction loss. The conventional multiloop control needs to sense the input current to yield the desired sinusoidal current waveform. This paper presents a control method for bridgeless PFC converter to provide sinusoidal current without sensing input current. The performance of the proposed method is demonstrated by the provided results with a 600W prototype.