傳統電池充電系統輸出端含有高成份的市頻漣波，導致電池受到熱循環而減少壽命。本論文研製一應用於電池充電系統之數位控制隔離型低市頻漣波雙向CLLC諧振轉換器，此轉換器使用碳化矽功率元件並可達到柔切特性並提升系統效率。本論文提出一適應性頻率調節法，利用輸入電壓漣波作為前饋控制調整適當的頻率變化，以降低輸出市頻漣波。本文首先分析此雙向諧振轉換器之動作原理，推導穩態等效模型及電壓增益曲線，設計出合適的頻率變化量做電壓調節。另外，設計CLLC諧振參數，使其具有CLLLC於充放電時之對稱特性，再利用數位訊號處理器TMS320F280049實作一低市頻漣波之實驗雛型，其額定功率為1.5 kW、直流匯流排電壓390 V、電池電壓130-170 V，以此驗證所提出方法之可行性。此轉換器操作於充電模式及放電模式下之最高轉換效率分別為96.7%及95.6%，其低頻漣波電壓較減少70%以上。

The output of the traditional battery charging system contains high double line frequency ripple content, which causes thermal cycling and short life cycle of the battery. In this thesis, a digital controlled isolated bidirectional resonant converter for battery charging system with low double line frequency ripple in charging stage is implemented. The full-bridge CLLC converter with silicon carbide power devices can achieve soft switching characteristic and higher efficiency. In addition, an adaptive frequency modulation method with the input voltage ripple feed-forward control is proposed to reduce the double line frequency ripple. The operating principles of bidirectional resonant converter are analyzed, the steady-state equivalent models and the voltage gain curves are derived, then appropriate frequency variation for output voltage regulation is designed. Also, the resonant tank of CLLC is carefully designed for achieving symmetrical operations as CLLLC in charging and discharging stages. A digital signal processor TMS320F280049 is used to implement laboratory prototype with rated power 1.5 kW, DC bus voltage 390 VDC, and battery voltage 130-170 VDC to verify the feasibility of the proposed method. The maximum conversion efficiency of CLLC converter in the charging stage and discharging stage are 96.7% and 95.6%, respectively. Moreover, the double line frequency ripple voltage can be reduced by 70% with the proposed algorithm.

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