Small signal analysis of current mode active-clamp ZVS dc-dc converters

Active clamp technique has been proved to be an important topology for pulse width modulated (PWM) converters featuring zero voltage switching (ZVS). The small signal modeling and analysis of current mode controlled active clamp ZVS dc-dc converters are presented in this paper. It is identified that, damping due to lossless resistance inherent in active clamp topology is eliminated under uncompensated current mode control. The buck converter is considered to demonstrate the small signal modeling of current mode controlled active clamp ZVS dc-dc converters. The analysis is also extended to boost and buck-boost converters and the same can be extended to complete family of active clamp dc-dc converters. The small signal model of active clamp converter is compared with the hard switched converters. Simulation results for the active clamp buck converter are presented.