A New High Voltage-Gain Converter with Coupled-Inductors and Voltage Multiplier

Abstract

High step-up techniques have been explored and developed for industrial applications over the past decades Especially for renewable energy systems the relatively low voltage must be boosted to high one for grid-connection applications In this thesis a new current-fed high step-up converter integrating coupled-inductors with voltage multiplier cell is proposed for applications in renewable energy systems With the current-fed configuration continuous low-ripple input current can be achieved which can avoid the use of input electrolytic capacitor to enhance the reliability of the whole system Also by employing the voltage step-up cell the voltage stress of the main switch is reduced and the leakage energy of coupled-inductors can be recycled to the output capacitor Therefore the low-voltage rated MOSFETs with low RDS_ON can be used to reduce the conduction losses In addition the reverse-recovery problem of the diodes is alleviated effectively by the leakage inductance as designed in the proposed circuit The operation principles the voltage stress analyses and the design guidelines of the components used in the proposed are discussed in detail in the thesis Finally a laboratory prototype circuit of 300 W 400 V output voltage with input voltage ranging from 30 to 42 V is implemented to verify the effectiveness of the proposed converter The results show that only one MOSFET is employed not only to simplify the circuit configuration but improve the system reliability A maximal efficiency of 95 63 % at 90 W and 92 98 % at the full load have been demonstrated in the experiments

Date of Award	2014 Aug 24
Original language	English
Supervisor	Hong-Tzer Yang (Supervisor)