Interleaved high step-up converter with coupled inductor and voltage multiplier for renewable energy system

Abstract

The concepts of dual coupled inductors and voltage multiplier cell are integrated to derive a novel non-isolated interleaved high step-up boost converter in this paper. At the input, due to the interleaved dual coupled inductors and voltage multiplier cell, the converter inhibits current ripple and reduced voltage stress for the power devices; At the output, the secondary sides of the two coupled inductors are connected in series to achieve the purpose of much higher voltage gain and lower voltage stress on the power devices. Therefore, lower voltage rating MOSFETs and diodes can be selected to reduce both switching and conduction losses. In addition, the leakage inductance energy of two coupled inductors can be absorbed and recycled to the output, and the reverse-recovery problem of diodes can be effectively suppressed. Zero current switching (ZCS) turn-on is realized for the power switches to reduce the switching loss. The working principle and steady-state characteristics of the converter are analyzed in detail. The voltage balance of the output capacitors and input current sharing by two interleaved phases are realized through the double closed-loop control of voltage and current. Finally, a 400 W laboratory prototype with 25~30 V input and 400 V output is built to verify the significant improvements of the proposed converter.