In this thesis, hard switching and soft switching current fed converters are investigated and two new ZVS current fed converters are introduced. First a new push-pull current fed converter is introduced. Auxiliary circuit in this converter not only provides soft switching conditions for all semiconductor devices but also absorb the voltage spikes across the switches due to the transformer leakage inductance. Then, a new ZVS high step up converter is presented. Also, in this thesis, an active clamp circuit is applied to single switch flyback current-fed converter and a new soft switching buck-boost converter is introduced. Finally, from this buck-boost converter, a new ZVS buck-boost converter with low number of components is driven and introduced. In this thesis, the proposed converters are completely analyzed and design considerations are discussed. Also, experimental results are presented to verify the presented theoretical analysis. Furthermore, in each chapter, the proposed converters are compared with other similar conventional soft switching converters by simulation results. Keywords Current fed converter, soft switching, ZVS, active clamp, step up, Buck-Boost
