Open AccessHigh step‐up/step‐down non‐isolated BDC with built‐in DC‐transformer for energy storage systems
Author(s) -
Wu Hongfei,
Lu Yangjun,
Chen Liqun,
Xu Peng,
Xiao Xi,
Xing Yan
Publication year - 2016
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2015.0841
Subject(s) - transformer , duty cycle , electrical engineering , forward converter , voltage , pulse width modulation , flyback transformer , electronic engineering , materials science , computer science , engineering , boost converter
A non‐isolated bidirectional DC–DC converter (BDC) is proposed for high step‐up/step‐down bidirectional power conversion applications. A DC‐transformer is integrated into a conventional non‐isolated buck–boost BDC to achieve high‐voltage conversion ratio and wide voltage/power range regulation simultaneously. The switches are shared by the buck–boost BDC and the DC‐transformer. Voltage stresses of switches are reduced by connecting the input and output of the DC‐transformer in‐series. The duty cycles of switches are used to make sure that the voltages on the two sides of the DC‐transformer are matched. As a result, the DC‐transformer always operates under the highest‐efficiency condition. The phase‐shift angle between the switching bridges is employed to achieve the power flow regulation. Soft‐switching of all the switches is achieved by adopting the pulse‐width modulation plus phase‐shift control strategy. Operation principles, characteristics and design considerations of the proposed BDC are analysed in detail. Experimental results from a 48 V/400 V–1 kW prototype verify the effectiveness of the proposed converter. The efficiency is demonstrated to peak at 96.6% for both the step‐up and step‐down modes.