Analysis of a soft switching interleaved converter without output inductor

A soft switching interleaved converter with series-connected transformers is presented in this paper. Based on the operation behavior in the proposed converter, each transformer of the series-connected transformers can be operated as an inductor or a transformer. Therefore no output filter inductor is needed in the converter. Asymmetrical pulse-width modulation (APWM) scheme is adopted to control the output voltage at the desired value. Based on the output capacitance of power switches and the resonant inductance including the external inductance and transformer leakage inductance, the resonance can be achieved at the transition interval. Therefore, the zero voltage switching (ZVS) turn-on of power switches can be realized. The voltage stress of switches is limited to equal input voltage. The center-tapped rectifier is used at the transformer secondary side to achieve full-wave rectification. The interleaved PWM operation can reduce the ripple current on the output capacitor. These features make the proposed converter suitable for the dc-dc converter with high output current. The operation principles, steady state analysis and design equations of the proposed converter are provided in detail. Finally, experimental results for a 240 W (12 V/20 A) prototype are provided to verify the feasibility of the proposed converter.