本文旨在探討市電併聯型光伏系統之設計且提出一最大功率演算法適用於前級轉換器控制電路並輸出交流電流滿足一般用電功率。在光伏系統中，前級採用降壓型轉換器，符合降壓升流，提高後級電流源變流器輸入電流的大小，並且針對兩倍瞬時功率的影響，傳統上使用電解電容來隔離交流訊號，本文於降壓型轉換器控制採用不同架構有效隔離交流市電的擾動，且減小電解電容的大小，使太陽能板維持穩定的輸出。後級採用電流源變流器，可以免除交流電流受輸出端交流市電的限制同時不用考量因為電壓源變流器為避免開關同時導通的空白時間設計。電流源變流器雖然控制簡單，但必須解決輸入電流源兩倍基頻諧波的問題，利用調整脈波寬度調變訊號以抵銷諧波訊號使輸出交流電流無低頻諧波。本文針對降壓型轉換器控制架構提出一最大功率演算法，有效達到最大功率點追蹤，使太陽能板維持最大功率輸出供後級電流源變流器轉換成交流電流。

This study presents a grid-connected photovoltaic system which is comprised of two stages: Buck DC/DC Converter and Current Source Inverter (CSI). The converter is used to buck the voltage and boost the current and provides a stable input power to the next stage. Conventionally, the electrolytic capacitor is used to isolate the disturbance caused by the ac output signals. The proposed control mechanism to the converter achieves an effective isolation from the grid-connected system, and also significantly reduces the size of electrolytic capacitor, so that the photovoltaic system provides a stable output. On the other hand, the CSI implements the inverter stage with a simpler control mechanism and has the inherent short circuit protection and the rapidness in system control. This study also proposes a simple way to obtain a reference voltage which makes sure the photovoltaic array to operate at the maximum power point.

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