Performance analysis of ZVT interleaved high step-up converter with built-in transformer

A non-isolated high-efficiency high step-up interleaved DC/DC converter is proposed for photovoltaic and fuel cell grid-connected power applications. The proposed converter consists of an interleaved structure, a built-in transformer and two sets of active clamp circuits. The built-in transformer can provide high voltage conversion ratio and increase the system efficiency without an extreme duty cycle compared with the conventional boost converter. The leakage inductance of the built-in transformer removes the output diode reverse-recovery problem. The active clamp scheme can suppress the surge voltage of the power MOSFETs and recycle the leakage energy. The operation principle of the converter is analyzed and verified. A 1 kW prototype with 40V input and 380V output is implemented and tested to show the performance of the proposed converter.