為了因應減緩全球暖化與空氣汙染等環境議題，研究再生能源系統被積極的提倡。太陽能發電系統由於潔淨、易於維護及對環境的影響小而成為再生能源當中受注目的選擇之一。對於大型的太陽能發電系統而言，發生部分遮蔽情形的可能性相當高。在部分遮蔽的情形下受遮蔽的太陽能電池呈現的行為是負載而不是發電，這些受遮蔽的太陽能電池的旁路二極體將會導通以避免這個問題。由於這些受遮蔽的太陽能電池被旁路，在功率-電壓曲線上將會呈現多個峰值。
許多最大功率追蹤策略在均勻日照下都是有效的並且已經歷過時間的考驗。然而，對於這些大部分是基於單一峰值的功率-電壓曲線的最大功率追蹤演算法則，多個峰值情形會使得效率降低。由於發生部分遮蔽的情形相當常見，因此有必要發展一新的最大功率追蹤演算法則以供太陽能發電系統在部分遮蔽情形下工作。
本論文針對在部分遮蔽情形下工作的太陽能發電系統發展一新的最大功率追蹤演算法則。所提出的最大功率追蹤演算法則是基於分段搜尋法並結合變步距的擾動與觀察法。以升壓型轉換器作為功率級，並以Microchip公司的微處理控制器dsPIC33FJ16GS502來作為最大功率追蹤控制器的實現。透過實驗以證實所提出演算法則的可行性與正確性。根據實驗結果，所提出的演算法則可以在多種不同的測試條件下追蹤到全域的最大功率點，並且追蹤的精確度超過99%。所提出的演算法則也可以在照度發生變動的情形下重新啟動追蹤。

Studies on renewable energy systems are actively being promoted in order to mitigate environmental issues such as the global warming and air pollution. Photovoltaic generation system (PGS) has become an attractive option among renewable energy sources because it is clean, maintenance-free and environmental friendly. For large PGS, the probability for partially shaded condition (PSC) to occur is high. Under PSC, the shaded cells behave as a load instead of a generator. Therefore, bypass diodes of these shaded cells will conduct to avoid this problem. Since the shaded cells are bypassed, multiple peaks in the P–V curve will be presented. There are many maximum power point tracking (MPPT) strategies that are effective and time tested under uniform solar insolation. However, the presence of multiple peaks reduces the effectiveness of most of the existing tracking algorithms, which assume a single peak power point on the P–V characteristic. Since the occurrence of partially shaded conditions is quite common, there is a need to develop a novel MPPT algorithm for PV systems operating under partially shaded conditions.
This thesis focuses on developing a novel MPPT algorithm for a PV system operating under PSC. The proposed MPPT algorithm is based on segmental search in combination with variable step-size perturb and observe (P&O) algorithm. A boost converter is used as the power stage and the MPPT controller is realized using microcontroller dsPIC33FJ16GS502 from Microchip corp. Experiments are carried out to validate the feasibility and correctness of the proposed algorithm. According to the experimental results, the proposed algorithm can track global maximum power point in various test conditions and the tracking accuracy is higher than 99%. The proposed algorithm can also restart tracking under irradiation changing conditions.

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