A novel topology of forward-flyback PFC converter with constant on-time control

A novel topology of forward-flyback power factor correction (PFC) converter with constant on-time control is proposed in this paper. The converter integrates the operation of a forward converter and a flyback converter. It operates either in the forward mode or the flyback mode depending on whether the input is higher or lower than the reflected output voltage to the transformer primary side. This integrated operation ensures that the dead zone problem of ac input current in conventional forward converters is overcome. It works for the universal ac input range and a high power factor is achieved. The proposed converter operates in critical conduction mode in order to achieve zero voltage switching and constant on-time control is applied. To confirm the validity of the proposed converter, simulations have been done using MATLAB/SIMULINK and are presented here.