全數位化非接觸定頻充電器之研製

本論文選用分離式變壓器作為非接觸式供電傳輸系統之關鍵元件，由於在非接觸式供電傳輸系統之第一級轉換器中，其二次側的所有訊息無法透過任何回授機制去告知一次側數位控制器。有鑑於此，在等同於一次側的地方繞製第三繞組，並由第三繞組去偵測二次側負載變動，將其變動量告知一次側的數位控制器，再經由控制器計算出一控制力來控制一次側上下橋開關的責任週期，以調節二次側電壓進而得到所需之輸出電壓。除此之外，於本論文中，加入一額外的第二級降壓式轉換器以進行電池管理。最後，再將一、二級串接起來，構成一完整非接觸式供電傳輸系統。為使所提之非接觸式供電系統更具完備及改善先期架構的缺點，以下提出兩個做法： 1. 提出具高圈數比的變壓器，所以可將第一級輸入電壓降至相對地低的輸出電壓，因此所對應到之第二級降壓式轉換器的責任週期相對地增大，如此一來可以提高第二級降壓式轉換器的效率。 2. 為解決非接觸式系統之第一級轉換器在變頻控制下且負載輕載時所產生電壓過高的缺點，本論文採用定頻調變責任週期的方式來克服此問題。基於成本考量下，本論文之非接觸式充電器的第一級轉換器係採用具有中心抽頭變壓器之半橋轉換器。之後，藉由最大功率傳輸以求得一、二次側串並聯補償電容之值，以提升整體之效率。另外，採用12V/12Ah 鉛酸電池四顆串聯以作為第二級轉換器的負載。於本論中，首先經由相關之理論推導後，以模擬來驗證所提架構之可行性。最後，採用Altera公司所生產的FPGA晶片EP2C20F484C8以做為整個系統的控制核心來實作驗證所提架構之有效性。

關鍵字

非接觸式供電傳輸系統；全數位化；非接觸充電器；定頻控制；分離式變壓器；最大功率轉移；半橋轉換器；電池管理； FPGA

並列摘要

In this thesis, a separated transformer is used as a key component in the isolated power-transferring system. Since the information on variations in load at the secondary side can not be passed to the primary side, the third winding is added to the primary side to obtain this information, such that the control effort created from the digital controller at the primary side can be obtained so as to control the high- and low-side switches to stabilize the corresponding output voltage. Moreover, the purpose of one additional buck converter after the secondary side is used to achieve battery management. In order to make the proposed isolated power-transferring system more practical than before and to remove some demerits in the existing structures, two methods are provided as follows: (1) A transformer with a high voltage turns ratio is utilized so as to reduce the voltage across the primary winding to the relatively low voltage across the secondary winding and hence to let the duty cycle of the buck converter be relatively increased, thereby causing the corresponding efficiency to be upgraded. (2) In order to overcome the problem in over voltage due to variable-frequency control at light load, the proposed control strategy in the first power stage adopts constant-frequency control. Taking the system cost into account, the first power stage of the isolated charger takes a half-bridge converter with a central-tapped transformer. By applying series compensation at the primary side and parallel compensation at the secondary side, the maximum power transfer is achieved, thereby upgrading the system efficiency. Furthermore, four lead-acid batteries are used as a load of the second power stage of the isolated charger. In this paper, first the mathematical deductions are given, next some simulated results are next provided to demonstrate the feasibility of the proposed topology, and finally one FPGA IC, named EP2C20F484C8, is used as a system control kernel to verify the effectiveness of the proposed scheme.

並列關鍵字

Isolated Power-Transferring System ； Fully-Digitalized ； Isolated Charger ； Constant-Frequency Control, ； Separated Transformer ； Maximum Power Transfer ； Half-Bridge Converter ； Battery Management ； FPGA

參考文獻

[45] 賈証主，VHDL數位系統設計與應用，台北，台科大圖書股份有限公司，2004。

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全數位化非接觸定頻充電器之研製

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