本文提出一新型單相七階換流器，此架構包含一直流電源、切換式電容電路以及耦合電感。相較於傳統七階換流器架構，本文提出之架構採用較少功率開關及二極體元件。此新型單相七階換流器可減少一顆電容，以增加電路穩定性，並提高整體壽命。藉由切換式電容電路與耦合電感，可使電容達到自我電壓平衡，且不需使用複雜的控制方法。此外，本文提出之架構可降低輸出電壓總諧波失真率。
最後，由模擬結果與實驗結果顯示，本文所提出之換流器於輸入電壓350-Vdc，輸出電壓380-Vac，輸出滿載3 kW下，其輸出電壓總諧波失真率為0.52 %，可驗證本文提出之多階換流器架構的可行性。

This thesis proposes a novel single-phase seven-level inverter. The topology of the proposed structure is composed of a DC source, a switched-capacitor circuit, and a coupled inductor. Compared to traditional seven-level inverter structure, the numbers of switches and diodes are reduced. The novel single-phase seven-level inverter reduces the number of capacitor by one, increasing the stability and life cycle of the circuit. The voltages of capacitors are self-balanced by switched-capacitor circuit and coupled inductor without complex control method. Therefore, the output voltage total harmonic distortion of the proposed structure can be reduced.
Finally, the simulation and experimental results show the 350-Vdc input voltage, 380-Vac output voltage, and 0.52 % output total harmonic distortion under 3 kW output power condition to verify the feasibility of the proposed multilevel inverter.

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