應用於電池儲能系統雙向電力潮流直流轉換器之建模與實現

Modeling and Implementation of a Bidirectional Power Flow DC Converter for Battery Energy Storage Systems

李孟儒(Meng-Ru Lee)

指導教授 ： 潘晴財

國立清華大學/電機資訊學院/電機工程學系/碩士(2010年)

摘要

由於潔淨式能源發電系統易受天候之影響，因此發電量不可預測且較為不穩定，例如太陽能發電及風力發電系統。若於潔淨式能源發電系統中加入適當儲能緩衝將有助於系統之安全運轉與供電品質之提升。本文主要研究目的在於提出一高性能之雙向電力轉換器，作為電池儲能系統之高壓側直流鏈與低壓側電池端能量轉換介面。
基本上，本論文之主要貢獻有三點，茲分述如下：首先本文提出一適用於電池儲能系統之雙向直流轉換器，電路主要特色為高壓側採用電容串聯方式，以降低各個功率開關截止時所承受跨壓，而低壓側則以電感並聯方式，以分擔低壓側大電流，進一步減少功率開關導通損失，且此電路拓樸具有高壓側電容自動均壓及低壓側電感自動均流特點。第二點貢獻則為針對本文所提雙向電力轉換器，分析其操作狀態與工作原理，更進一步推導出直流與小信號數學模型，故可知電路穩態特性並可作為閉迴路控制器之依據。第三點，本論文並實際製作出一額定功率為450W，高壓側直流鏈電壓300V以及低壓側電池電壓為25V之雛形系統。實測結果轉換器工作於降壓模式最高效率約93.4%，而升壓模式最高效率約為94.3%。

關鍵字

再生能源 ； 電池儲能系統 ； 雙向直流轉換器 ； 交錯式控制 ； 直流鏈

並列摘要

Due to the unpredictable characteristic of renewable energy systems such as photovoltaic and wind energy systems, an energy storage subsystem is essential as a buffer for enhancing the safety and power quality of the whole system. Hence, the main purpose of this thesis is focused on the battery energy storage system (BESS) and to propose a high performance dc converter, as an interface between the high voltage DC bus and the low voltage battery.
Basically, the major contributions of this thesis can be summarized as follows. First, a new bidirectional dc converter structure with high voltage side in series and low voltage side in parallel is proposed for the battery energy storage system. This new topology can achieve uniform voltage sharing for the active switches in high voltage side and uniform current sharing for the active switches in low voltage side automatically. It is seen that due to the reduced voltage and current stress of the active switches in the proposed converters as well as the interleaved control strategy, much better efficiency and power quality can be achieved. Second, based on the state space averaging technique, the correspond DC and AC models are derived for convenient design of the proposed converter. Finally, a prototype with 300V DC bus voltage and 25V battery voltage is implemented to verify the validity of the proposed converter. It is seen that maximum efficiency of the converter is 93.4% and 94.3% can be achieved for step-down and step-up operation modes respectively.

並列關鍵字

renewable energy ； battery energy storage system ； bidirectional dc converter ； interleave control ； DC bus

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