Analysis and design of a push-pull DCM boost power factor corrector

A novel power factor corrector (PFC) composed of two-phase discontinuous conduction mode (DCM) boost PFCs and a coupled inductor is proposed in this paper. By coupling the two-phase boost inductors into the same magnetic core, both the circuit volume and the input ripple current are reduced. Therefore, the power factor (PF) value and the power density are improved. In addition, the output capacitor size can be smaller. The proposed topology distributes the input current and output current equally for the two phase modules. A cut-in-half duty cycle can decrease the conduction losses of the switches, and both the turns and diameters of the inductor windings, which help more to the reduction of the circuit volume. The advantages of a DCM boost PFC, such as natural zero-current-switching (ZCS) of the output diode, a natural PFC function, and the simplified EMI filter design, are maintained. Detailed analysis and design of the proposed topology, and the experimental results on a prototype with a 380-V output voltage and a 200-W output power are provided.