| Abstract |
A novel unity power-factor rectifier scheme is proposed, which combines the benefits of both types of APFC: single stage and two stage schemes. Thus it benefits of high efficiency (like a single stage rectifier) and good output voltage regulation (like a two stage rectifier). The proposed scheme employs two stages, connected in series at the output as opposed to cascaded in common two stage rectifiers. The second stage is responsible for dynamic active cancellation of the output ripple solely. Theoretical explanation is provided through the analysis of the power flow in the scheme. A 200W, 220VAC to 48VDC converter prototype was built and tested, which experimentally validates the proposed approach. In this prototype, output ripple was –40dB suppressed from 4.4V to 30mV and an overall efficiency of over 90% was achieved. |
