Research Of Single-Stage PFC Converter With Asymmetrical Half-Bridge And Current-Doubler Rectifier

Power factor correction (PFC) and soft-switching technique are two important research subjects in power electronics. With only one set of control system, single-stage PFC converter can realize the input current shaping and the fast regulation of output voltage. It has higher performance than two-stage ones because of the advantage of simple structure and low cost in low power electronic converters.A single-stage PFC DC/DC converter is developed. The circuit utilizes the characteristic of asymmetrical half-bridge to achieve zero voltage switching (ZVS) of the main switch and the auxiliary switch by the resonance of transformer leakage and parasitic capacitance of MOSFET switches. In the secondary side of the transformer, current-doubler rectifier makes the current of output rectifier diode inverts naturally, and two output inductors connect in an interleaving way. It helps to make the current ripple significantly low, and the inductor's size is reduced, so the size and weight of the system is decreased.A small signal average circuit model of the power stage is established by state-space averaging method. The characteristic of stabilization and dynamic is analyzed and the compensator is designed basing on it.The experimental result is given in the last part of the thesis. Both functions of PFC and soft-switching condition of all the power switches are achieved. The switching loss is reduced, and the EMC capability is improved, a satisfied result is obtained.