對許多需求電壓較高的應用而言，通常會由數個電池串聯而成的電池組加以供電。在串聯使用時，個別電池可能會發生電壓及電量不均衡的情況；此一不均衡在充電或者放電階段均可能發生。電池間的不均衡會影響充電效率及電池壽命。因此，在串聯電池組的使用上，電量平衡是一個重要的議題。本論文的主要目的即是嘗試去提出方法來解決此一電量平衡的問題。
論文首先藉由一組連續的充放電實驗說明電量平衡的重要性，並且介紹各種充電模式以及各種文獻中所提及的平衡充電的方法。為了提昇電量平衡的效果，本文發展出一個以降升壓轉換電路為基礎的動態平衡充電策略。我們分別以é前向式均分û及é後向式均分û兩種電路架構來實現此一策略。藉由此一動態的能量再均分程序，串聯電池組能夠更有效率地達成平衡狀態；因為能量將會由電量較多的電池上取出，並均分給其他電量較少的電池。這些電路是由數個構造相同的副電路所組成，在電路控制上並且採用數位的微處理器。而由於副電路個數可以容易的調整，因此電路可以擴充，以適用於不同電池數目的電池組。
上述的平衡充電電路甚至可以應用在離線或者是放電使用的情況之下。基於放電使用時，電池組的電壓範圍有相當大的變動；我們可以將平衡放電及電壓調整的機制整合在一起。本文並提出一個以多繞組變壓器為基礎的平衡放電電路架構。
本文的實驗是以鉛酸電池做為實驗電池，因此文中也介紹了鉛酸電池的反應及特性。然而這些電路並不限定使用於特定的電池種類上。實驗結果證實理論上的分析，並驗證這些電路架構的可行性。

Charge equalization is a major issue in the service of batteries since they are frequently connected in series to obtain higher output voltage levels for most applications. With series connection, imbalance may happen to the operating batteries during either charging or discharging periods. The imbalance among batteries concerns the operating efficiency and the battery lifetime. The main object of this dissertation is to solve the problem of charge inequality.
The importance of charge equalization is first addressed. The problem is demonstrated by experiments of charging/discharging processes. Then, the techniques of battery charging and charge equalization are reviewed.
To improve charge equalization, a dynamic balance charging scheme is developed on the basis of buck-boost conversion. The balance charging scheme can be realized by two configurations, that is, “forward allotting” or “backward allotting” configurations. The circuits are composed of several duplicated subcircuits and operated by digital control kernel, therefore, they are easy to be applied on battery sets with different numbers of batteries. By dynamically re-allocating the energy drawing from satiated batteries and allotted to hungry ones, the series-connected batteries can reach balance state more efficiently.
The balance charging circuits can be employed during off-line or even discharging. However, on observing that the output voltage will vary in a big range when the battery set is discharged, the charge equalization can be integrated with voltage regulation on the output. Evolve from this idea, a balance discharging circuit　topology based on multi-winding transformer is proposed.
The experiments in this dissertation are carried out on lead-acid batteries, therefore, the reactions and characteristics of lead-acid batteries are discussed. However, the proposed circuits are not restricted to be applied on lead-acid batteries only. Experimental results confirm the theoretical analyses and manifest the effectiveness of the designed circuits.

CHAPTER 1 INTRODUCTION 1
1.1 RESEARCH MOTIVATION 1
1.2 INVESTIGATION ON CHARGE IMBALANCE 3
1.3 LITERATURE REVIEW 6
1.4 CONTENT ARRANGEMENT 8
CHAPTER 2 INTRODUCTION TO LEAD-ACID BATTERIES 10
2.1 STRUCTURE AND REACTIONS 10
2.2 BATTERY CHARGE AND DISCHARGE 14
2.3 POLARIZATIONS OF BATTERIES 16
2.4 CHARGING MODES 19
2.5 CAPACITY OF BATTERY AND DETECTION 24
2.6 FACTORS INFLUENCING HEALTH OF LEAD-ACID BATTERIES 29
CHAPTER 3 FORWARD ALLOTTING CHARGE EQUALIZATION 32
3.1 CIRCUIT CONFIGURATION 33
3.2 CIRCUIT OPERATION 35
3.3 CONTROL ALGORITHM 39
3.4 CIRCUIT ANALYSIS 40
3.5 EXPERIMENTAL RESULTS 44
CHAPTER 4 BACKWARD ALLOTTING CHARGE EQUALIZATION 48
4.1 CIRCUIT CONFIGURATION 48
4.2 CIRCUIT ANALYSIS 52
4.3 CONTROL ALGORITHM 54
4.4 EXPERIMENTAL RESULTS 57
CHAPTER 5 CHARGE EQUALIZATION ON DISCHARGING 61
5.1 CANDIDATE CIRCUITS FOR CHARGE EQUALIZATION ON DISCHARGING 61
5.2 CHARGE EQUALIZATION WITH OUTPUT REGULATION 64
5.2.1 Flyback conversion 65
5.2.2 Forward conversion 66
5.3 EXPERIMENTAL RESULTS 67
CHAPTER 6 CONCLUSIONS AND DISCUSSIONS 70
REFERENCES 73

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