A new PFC converter with reduced output bus capacitors

A new PFC converter with reduced bus capacitor has been proposed. It detaches the traditional output bus capacitor into two parts, and adds an auxiliary power switch in traditional PFC converter. The converter operated in normal PFC mode when the line is normal and switch to another boost mode as the ac line is faulty. The added boost mode can convert the energy of the big bus capacitor to the little bus capacitor and back-end converter, which increase the hold-up time. The relationship between the hold-up time and acquired capacitor is derived. Experimental prototype converter, compared with the conventional PFC circuit, proves the hold-up time is extended to 2.5 times.