Interleaved push-pull converter with very low input and high output

This paper discusses a novel high-efficiency interleaving push-pull converter with very low input voltage and high output voltage. Such push-pull converter should be used as high capacity battery discharger, and has the capability to feedback the discharging energy to the grid if it is cascaded with an inverter. The main characteristics of such push-pull converter are high voltage turns ratio, all transformer primaries in parallel and secondary output rectifiers in series. This paper proposes the operation principle, features and design consideration of this push-pull converter. The circuit analysis shows duty cycle loss may exist at the secondary side of the transformer in such interleaved topology. However, good transformer structure design and proper interleaved number can minimize this effect. A 150 W, 34 kHz prototype verifies the effectiveness of the proposed interleaved push-pull converter.