基於扁平矩陣變壓器之新型隔離式四相直流轉換器

A Novel Isolated Four-Phase DC Converter Based on Flat Matrix Transformer

江俊緯(Chun-Wei Chiang)

指導教授 ： 潘晴財 ； 王信雄

國立清華大學/電機資訊學院/電機工程學系/碩士(2006年)

摘要

為了因應能源短缺和環保意識的高漲，燃料電池的開發以及其相關之研究已是目前最熱門的研究領域。因此一個介於燃料電池和負载之間界面的高電壓增益轉換器即扮演一個重要的角色。然而此轉換器需要一個可以提供升壓與電氣隔離功能之變壓器(即需要一個高匝數比之變壓器)，但伴隨著的結果則是會有造成低效率與高電壓應力的漏電感產生。此種現象在高功率額定的情況下更是嚴重。有鑒於此，本論文提出一基於扁平矩陣變壓器之新型四相隔離式直流轉換器架構，以解決上述對於高功率情況下之問題。

本論文之貢獻可歸納為四點：第一，針對新架構使用之低漏電感的扁平矩陣變壓器(耦合係數幾乎為1)，提出其等效電路，使矩陣變壓器可以與其它電路元件整合起來，而在電路模擬軟體中(如Pspice )模擬其電路特性。第二，針對扁平矩陣變壓器進行分流特性分析與驗證，使扁平矩陣變壓器之理論更加完善。第三，針對高功率、高電壓增益之應用情況下，提出一新型四相隔離式直流轉換器架構，利用新型之交錯控制法，結合新型之變壓器連接結構，使轉換器輸出電壓可達到3n倍之輸入電壓(n為變壓器之匝數比)，且輸出電壓漣波頻率也增加到八倍之開關切換頻率。因此變壓器之匝數比與輸出濾波器之大小都可以被縮小。第四，利用德州儀器公司新上市之TMS320F2812快速數位訊號處理器，經由該雛型之實驗結果，證實本論文所提新型轉換器之可行性。

關鍵字

扁平矩陣變壓器 ； 四相 ； 直流轉換器 ； 電氣隔離

並列摘要

In view of the rapid growth of fuel-cells applications, a high voltage gain converter is essential as an efficient interface between the loads and the fuel cells. Naturally, one can use a transformer to achieve the high voltage gain as well as provide electrical isolation. However, a high turn-ratio transformer always accompanies high leakage inductance which results in low efficiency and high electric stress of devices. This situation becomes even worse for high power rating case. In light of these dilemmas, a novel isolated four-phase DC converter base on flat matrix transformer is proposed in this thesis to solve the above problems for high power application.

Basically, the contributions of this thesis may be summarized as follows. First, a correct equivalent circuit model is proposed for the adopted flat matrix transformers with very low leakage inductance (almost unity coupling coefficient) and with possible fraction-turn windings. Then, based on the proposed model matrix transformers can be integrated with other circuit components to obtain a system model convenient for simulation with a commercial software such PSpice. Second, the sharing characteristic of flat matrix transformers is analyzed and verified. Third, a novel isolated four-phase DC converter is proposed for high power high voltage-gain applications. By using a new interleaved control to together with a new transformer interconnection configuration, the converter output voltage can reach 3n, n being the transformer turn-ratio, times the input voltage and the output voltage-ripple frequency is increased to 8 times the switching frequency. As a results, the size of the output filter and the turn-ratio of the transformer can be reduced. Finally, a prototype is also constructed by using a high speed digital signal processor, namely TMS320F2812 to verify the feasibility of the proposed converter.

並列關鍵字

Flat matrix transformer ； DC Converter ； Four-phase ； electrical isolation

參考文獻

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