諧振轉換器因為擁有降低切換損失及高頻操作的特性，所以能夠利用諧振電流近似正弦波及零電壓切換來穩定輸出，同時能大幅降低切換損失並且減少雜訊。在眾多諧振轉換器中，LLC諧振轉換器除了具備在寬負載範圍能穩壓輸出外，也可在小頻寬範圍內做負載變動，以及操作的頻率範圍均能達ZVS的優點。
本文主要為研製一個500 W輸出之數位控制LLC諧振轉換器。開關控制信號使用Microchip開發的低成本數位處理器dsPIC33FJ16GS502來實現。文中首先針對所使用之系統的硬體與軟體進行深入地探討，並且提出系統設計上的考量。接著對系統損耗進行分析，並研究盲時區間對效率之影響。根據實驗結果，本文所提出之數位控制LLC諧振轉換器之效率，在所有負載條件下均可以達到90%以上。

Resonant converters can reduce switching losses and allow for high-frequency operation, these techniques process power in a sinusoidal manner and achieves zero voltage switching (ZVS). Therefore, the switching losses and noises can be dramatically reduced. Among resonant converters, LLC resonant converter has advantages such as regulating the output voltage over wide line and load variations with a relatively small variation of switching frequency, and achieving ZVS over the entire operating range.
In this thesis, a 500 W digitally-controlled LLC resonant converter is implemented and studied. The gating signals of the power switches are generated using a low cost digital signal controller dsPIC33FJ16GS502 from Microchip corp. Detailed description about the hardware and firmware parts of the system will be presented first and the design considerations will be discussed. Next, the losses analysis will be performed, and the effect of the dead time values on the converter efficiency will also be investigated. According to the experimental results, the proposed digitally-controlled LLC resonant converter can achieve efficiencies higher than 90 % under all load conditions.

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