IEEE 16-Analysis, design and implementation of active clamp zero voltage switching converter with output ripple current cancellation


system analysis and circuit implementation of an active clamp converter with current
doubler rectifier to reduce the voltage stress of the switching device and the current stress of the
transformer secondary winding is presented. An active clamp circuit based on one auxiliary switch
and one clamp capacitor is used to recycle the energy stored in the transformer leakage in order to
minimise the spike voltage at the transformer primary side and reduce the voltage stress of the
switching devices. The resonant behaviour, based on the output capacitance and leakage
inductance of the transformer during the transition interval between the main and auxiliary
switches in the proposed converter, is used to achieve zero voltage switching. Therefore the
switching losses of the switching devices are reduced. For the output stage, the current doubler
rectifier offers ripple current cancellation at the output capacitor and reduces the current stress of
the transformer secondary winding. The winding turns of the current doubler rectifier are also
reduced compared with the center-tapped rectifier. The circuit configuration and operating
principle of the proposed converter are analysed and discussed. The design considerations of the
circuit are presented. Finally experimental results for a 150W(5V/30A) prototype are presented to
verify the theoretical analysis and circuit performance.