A high step-up passive absorption circuit used in non-isolated high step-up converter

To obtain a high step-up gain with high efficiency in distributed power sources application, such as photovoltaic and fuel cells, a passive absorption with voltage multiplier character is inserted in the interleaved Flyback-Forward converter to provide another design freedom for leakage energy recycle and voltage gain extension. By high step-up passive-clamp circuit, the voltage spikes on the MOSFETs are clamped and the energy in leakage inductance of coupled inductor can be recycled to get high output voltage. Moreover, high voltage-conversion ratio is achieved. The operational principle and characteristics of the proposed converter are presented, and verified experimentally with a 500W prototype converter.