ZHAO Siyang, ZHANG Junming, ZENG Hulong

 

(College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China)

 

 

Abstract: Aiming at solving the problem of the inherent input current dead zone of stepdown power factor correction (Buck PFC) converter, a hybrid stepdown PFC converter was proposed, which was comprised of Buck PFC converter and an auxiliary converter. By making the auxiliary converter operating when the input voltage instantaneous value was lower than the output voltage, the input current dead zone was eliminated. The hybrid converter had the advantages of low output voltage and high efficiency at low input voltage, which was the same as Buck converter, and the input current waveform of hybrid converter was improved obviously. The experimental results indicate that the power factor of the hybrid converter at 90V input voltage is 0.99, which is 0.09 higher than that of Buck PFC converter. The total harmonic distortion (THD) of the hybrid converter at 115V input voltage is 8%, which is about 20% lower than that of Buck PFC converter. And the efficiency of hybrid converter is just 0.5% lower than that of Buck converter.

 

Key words: input current distortion; ACDC converter; power factor correction