本論文研製三階半橋雙向諧振式直流轉換器，此轉換器可應用於直流匯流排與電池間之能量傳遞，藉由三階半橋CLLLC諧振轉換器擁有對稱特性與可達到柔性切換以減少開關切換損失，此外利用三階電路特性來降低開關電壓應力，以提升系統效率。本文將探討三階半橋雙向直流諧振轉換器動作原理並推導諧振槽之轉移函數。最後實作出一額定功率2 kW，輸入電壓400 V、輸出電壓250~400 V之實驗雛形以驗證理論分析，此轉換器操作於充電模式下最高轉換效率在800 W為94.8%，操作於放電模式下最高轉換效率在1000 W為95.1%

A three-level half bridge bidirectional resonant converter for the energy transferring between the DC bus and the battery of the electric vehicle is designed and implemented in this thesis. The three-level half-bridge CLLLC has the symmetrical characteristics and can achieve soft switching for reducing the switching losses. In addition, the voltage stress of power switches can be reduced with the three-level topology for improving the system efficiency. The operating principles of three-level half bridge bidirectional resonant converter are discussed in detail. Then, the steady-state equivalent models and the transfer functions of the resonant tank are also derived. Finally, a laboratory prototype with rated power 2 kW, DC bus voltage 400 V and battery voltage 250~400 V is implemented to validate the theoretical analysis. The highest efficiency in the charging and discharging stages are 94.8% at 800 W and 95.1% at 1 kW, respectively

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