Open AccessHigh boost‐ratio bidirectional converter for interfacing low‐voltage battery energy storage system to a DC bus
Author(s) -
Muchina Eliud G.,
Masike Lebogang,
Njoroge Gitau Michael
Publication year - 2019
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.2018.6083
Subject(s) - electrical engineering , battery (electricity) , boost converter , voltage , capacitor , snubber , forward converter , computer science , converters , energy storage , engineering , electronic engineering , power (physics) , physics , quantum mechanics
Supply and demand mismatches in renewable energy systems are addressed by integrating battery banks. Selecting battery bank terminal voltage to match DC‐bus voltage (350–450 V for single‐phase AC loads), necessitates employing battery banks with long‐string connections along with their attendant shortcomings. To employ short‐string battery banks, high‐boost‐ratio bidirectional interfaces are required between the DC‐bus and battery bank. Current literature lacks a single source where high‐boost‐ratio converters’ are categorised and their strengths and weaknesses identified. Comprehensive literature review is hence carried out to determine attributes of various high‐boost‐ratio DC–DC converters and also categorise them. The key attributes of a topology to interface battery storage to a DC‐bus are determined. Based on these a bidirectional tapped‐inductor boost converter emerges as the best candidate. Moreover, in order to regulate output voltage, voltage‐gain versus duty‐ratio characteristics should not be very steep. Since battery terminal voltage varies with state‐of‐charge, closed‐loop control is necessary. Converter's small‐signal transfer‐functions are derived and a two‐loop controller to regulate output voltage and inductor current while allowing bidirectional power flow designed. A novel bidirectional passive lossless snubber circuit is employed to clamp the voltage spikes across the active switches, without altering the normal operation of the converter.