Abstract-
A wide range active clamp two-switch converter with
current doubler rectifier (CDR) is presented in this paper. An
active clamp circuit based on two clamp switches and one clamp
capacitor are used to recycle the energy stored in the transformer
leakage inductor to minimize the spike voltage at the transformer
primary side and reduce the voltage stress of switching devices.
The resonant behavior based on the output capacitance and
leakage inductance of the transformer during the transition
interval between the main and clamp switches in the proposed
converter is used to achieve ZVS operation of main switching
devices. The duty ratio of main switching devices in the proposed
converter can be more than 50% of the conventional forward
converter. In the output stage of the proposed converter, the CDR
circuit offers the ripple current cancellation at the output
capacitor and reduces the current stress of transformer secondary
winding. The winding turn of the current doubler rectifier is also
reduced compared with the winding turn of the center-tapped
rectifier. The circuit configuration and the principle of operation
are analyzed and discussed. The design considerations of the
proposed converter are provided. Finally, the characteristics of
the proposed converter are verified on a 130V-350V input and
5V/20A output experimental prototype.
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