shows a circuit diagram of the proposed converter.
The proposed converter in Fig.1 is the asymmetrical halfbridge
converter integrated with the bridgeless boost rectifier
[2]. The bridgeless boost rectifier consists of the boost
inductor Lb, dc-link capacitor Cd, and switching devices D1, D2,
S1, and S2, respectively. D1 and D2 are slow-recovery diodes.
S1 and S2 are MOSFETs with output capacitors CS1 and CS2
(CS = CS1 = CS2), respectively. DS1 and DS2 are body diodes of
S1 and S2, respectively. The APWM half-bridge dc-dc
converter consists of the dc-link capacitor Cd, switching
devices S1, and S2 with output capacitors CS1 and CS2, blocking
capacitor Cb, transformers T1, and T2 output diodes Do1 and
Do2, and output capacitor Co. By sharing Cd, S1, and S2, the
proposed converter integrates the operation of the bridgeless
PFC boost rectifier and the APWM half-bridge dc-dc
converter. S1 and S2 are controlled asymmetrically.
By allowing the boost inductor to operate in DCM, PFC
and fast output voltage regulation are performed
simultaneously by the APWM control of power switches.
For both positive and negative half-line cycle of Vb the
proposed converter has symmetric operation. In the positive
half-line cycle, S1 is controlled with duty ratio D.