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

In this paper, a high step-up interleaved zero-current-switching (ZCS) converter with built-in transformer voltage multiplier is proposed for the high large voltage gain conversion systems. The turns ratio of the built-in transformer can be employed as another control freedom to extend the voltage gain without extreme duty cycle, which is existed in the conventional interleaved boost converter. Furthermore, the switch voltage stress can also be reduced by the built-in transformer voltage multiplier to make the low voltage rated power MOSFETs available to reduce the switch conduction losses. In addition, the diode reverse-recovery problem can be alleviated by the inherent leakage inductance of the built-in transformer, which can reduce the reverse-recovery losses. Finally, a 40V-input 380V-output 1kW prototype is built to demonstrate the effectiveness of the theoretical analysis.