本論文提出一新型的台科大多階轉換器(Taiwan Tech Multi-Level Converter, TMC)，適用於高輸入電壓的電力轉換需求。其基本的二階LLC電路為將傳統半橋LLC轉換器的變壓器之原邊繞組修改成兩組相同的繞組與一嵌位電容所組成。若在其中插入N個多階電路單元(Multi-Level Cell，每個MLC都具有兩個電容器與兩個串聯的切換開關），將可擴充成為(N+2)階之TMC-LLC電路。
因TMC-LLC電路除了具有LLC諧振轉換器相同的優點：電路簡單，MOSFET的零電壓切換（ZVS），整流二極體的零電流切換（ZCS），高轉換效率性能外，毋須外加任何嵌位機制電路或複雜控制時序的驅動信號，每個開關的電壓應力都被嵌位於2*Vi/m, (其中之m為串聯之開關總數目），同時其輸入電流的di/dt又被有效的降低，得以使用較小的EMI濾波器組件，就可以滿足EMI規格，實現更高的功率密度性能。
所提出的電路工作原理，將以Simplis的模擬波形解說，並以三階LLC諧振轉換器為設計範例，500-550 V 輸入電壓, 220V/ 1.2A 輸出電壓與電流為實作規格，具體驗證此一電路架構的可實現性。

A novel Taiwan Tech Multi-Level Converter (TMC) is proposed for high-voltage input power conversion applications in this thesis. A basic two-level LLC circuit is obtained by modifying the conventional half-bridge LLC converter with a dual-primary transformer and a clamping capacitor. By stacking N multi-level cells (MLC, each with two capacitors and two series switches) inserted into two-level circuit, consequently, a desired (N+2)-level TMC is derived.
TMC-LLC resonant converter is containing LLC features such as zero-voltage switching (ZVS) of MOSFETs, zero-current switching (ZCS) of rectifier diodes, simple circuitry, and high efficiency. In addition the voltage stress on each switch is well-clamped to 2*Vi/m, (m: the total number of series-connected switch) without any clamping mechanism and/or complicated control timing driver signals. Moreover, it can effectively reduce the input current ripple resulting in reducing di/dt noise. Consequently, smaller EMI filter components can be used to further improve power density performance. The proposed topology operation is illustrated by Simplis simulation waveforms and a TMC-TL-LLC with 500-550 V input, 220V/ 1.2A output power is built to verify theoretical analysis.

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