Development of a SOC-based Lithium-ion Battery Equalizer
碩士 === 國立臺灣科技大學 === 電機工程系 === 106 === In this thesis, a state-of-charge (SOC)-based equalizing circuit for series-connected lithium-ion batteries is proposed. The power stage utilized in this thesis is a bidirectional buck-boost converter. Using this topology, bidirectional energy transfers between...
Main Authors: | , |
---|---|
Other Authors: | |
Format: | Others |
Language: | zh-TW |
Published: |
2018
|
Online Access: | http://ndltd.ncl.edu.tw/handle/spdu9c |
id |
ndltd-TW-106NTUS5442182 |
---|---|
record_format |
oai_dc |
spelling |
ndltd-TW-106NTUS54421822019-05-16T00:59:41Z http://ndltd.ncl.edu.tw/handle/spdu9c Development of a SOC-based Lithium-ion Battery Equalizer 以剩餘容量為基礎之鋰離子電池平衡電路 Po-Han Liao 廖柏涵 碩士 國立臺灣科技大學 電機工程系 106 In this thesis, a state-of-charge (SOC)-based equalizing circuit for series-connected lithium-ion batteries is proposed. The power stage utilized in this thesis is a bidirectional buck-boost converter. Using this topology, bidirectional energy transfers between two individual cells can be achieved. Comparing with voltage-based balancing strategies which are widely used in equalizing circuits, SOC-based balancing strategies are more effective due to the flatness of open circuit voltage (OCV) versus SOC characteristics. For SOC-based balancing algorithms, an accurate SOC estimation is essential. In this thesis, a compensated OCV-based SOC estimation method is proposed for improving the accuracy of SOC estimation. However, if the duty cycle of the bidirectional buck-boost converter is kept constant, the balancing current will decrease as the SOC difference decreases; this will correspondingly increase the balancing time. To deal with this problem, two balancing algorithm named varied-duty-cycle method and curve-fitting method are proposed. These presented techniques can adjust the duty cycle value according to the SOC difference and keeps the balancing current nearly constant. Comparing with fixed-duty-cycle approach and varied-duty-cycle method, the curve-fitting method can improve the balancing time by 27.1 % and 18.6 %, respectively. Yi-Hua Liu 劉益華 2018 學位論文 ; thesis 101 zh-TW |
collection |
NDLTD |
language |
zh-TW |
format |
Others
|
sources |
NDLTD |
description |
碩士 === 國立臺灣科技大學 === 電機工程系 === 106 === In this thesis, a state-of-charge (SOC)-based equalizing circuit for series-connected lithium-ion batteries is proposed. The power stage utilized in this thesis is a bidirectional buck-boost converter. Using this topology, bidirectional energy transfers between two individual cells can be achieved. Comparing with voltage-based balancing strategies which are widely used in equalizing circuits, SOC-based balancing strategies are more effective due to the flatness of open circuit voltage (OCV) versus SOC characteristics. For SOC-based balancing algorithms, an accurate SOC estimation is essential. In this thesis, a compensated OCV-based SOC estimation method is proposed for improving the accuracy of SOC estimation.
However, if the duty cycle of the bidirectional buck-boost converter is kept constant, the balancing current will decrease as the SOC difference decreases; this will correspondingly increase the balancing time. To deal with this problem, two balancing algorithm named varied-duty-cycle method and curve-fitting method are proposed. These presented techniques can adjust the duty cycle value according to the SOC difference and keeps the balancing current nearly constant. Comparing with fixed-duty-cycle approach and varied-duty-cycle method, the curve-fitting method can improve the balancing time by 27.1 % and 18.6 %, respectively.
|
author2 |
Yi-Hua Liu |
author_facet |
Yi-Hua Liu Po-Han Liao 廖柏涵 |
author |
Po-Han Liao 廖柏涵 |
spellingShingle |
Po-Han Liao 廖柏涵 Development of a SOC-based Lithium-ion Battery Equalizer |
author_sort |
Po-Han Liao |
title |
Development of a SOC-based Lithium-ion Battery Equalizer |
title_short |
Development of a SOC-based Lithium-ion Battery Equalizer |
title_full |
Development of a SOC-based Lithium-ion Battery Equalizer |
title_fullStr |
Development of a SOC-based Lithium-ion Battery Equalizer |
title_full_unstemmed |
Development of a SOC-based Lithium-ion Battery Equalizer |
title_sort |
development of a soc-based lithium-ion battery equalizer |
publishDate |
2018 |
url |
http://ndltd.ncl.edu.tw/handle/spdu9c |
work_keys_str_mv |
AT pohanliao developmentofasocbasedlithiumionbatteryequalizer AT liàobǎihán developmentofasocbasedlithiumionbatteryequalizer AT pohanliao yǐshèngyúróngliàngwèijīchǔzhīlǐlízidiànchípínghéngdiànlù AT liàobǎihán yǐshèngyúróngliàngwèijīchǔzhīlǐlízidiànchípínghéngdiànlù |
_version_ |
1719172460389072896 |