全數位化單級式太陽能照明系統之研製

本論文研製一數位化單級式太陽能照明系統，以升壓型諧振式電路作為電力調節裝置，可操作於直流升壓或高頻弦波輸出模式，亦可同時操作於直流與交流雙輸出模式；其中直流輸出使用於電池充電，交流輸出使用於螢光燈負載。在雙向連續導通與電感性負載為設計條件下，電路開關切換具有零電壓導通特性，電路除了結構簡單，可雙向使用之特點外，尚有轉換效率高等優點。本論文系統以微控制器PIC18F452為控制單元，結合最大功率追蹤控制與充放電控制於同級電路。白天日照充足條件下，系統操作於充電模式，利用調變責任周期進行最大功率追蹤對電池充電；夜晚則為放電模式，利用調變切換頻率驅動螢光燈管。系統之控制皆以軟體完成，可簡化複雜的運作模式，亦可減少硬體電路成本。經由理論分析、設計與模擬，本論文實際製作一90W之單級式之太陽能照明系統，以蓄電池(12V/3AH×3)與螢光燈(T5/35W×2)為負載，進行系統功能驗證與測試。由實驗結果顯示，理論分析與實測結果相當一致，系統功能亦可達到設計之目標。其中系統操作於充電模式時，效率可達86.63%，操作於放電點燈模式時，效率可達90.26%。

關鍵字

單級式升壓型諧振電路；最大功率追蹤；太陽能照明；微控制處理器

並列摘要

This paper presents a digital single-stage power converter for photovoltaic energy conversion application. The presented power converter consists of a boost type resonant circuit from which both DC and AC outputs are provided. The DC output is used to charge batteries and the AC output is applied for lighting purpose. With the conditions of continuous conduction and inductive load, the switches in the boost resonant converter can be turned on with ZVS. The advantages of the proposed boost resonant converter include simple structure, multiple outputs, and high energy efficiency. The system uses the PIC18F452 microcontroller as the core control unit. The maximum power point tracking control and battery charge-discharge controls are all implemented in the single unit. The system utilizes the duty cycle modulation in the day time to control the maximum power point tracking and battery charge, and the frequency modulation in the night time to control the battery discharge for lighting fluorescent lamps. All the control algorithms finished in the same microcontroller result in simple control mechanism and circuit cost reduction. Apart from theoretical analysis, design and computer simulation, an experimental prototype converter with power output 90W is constructed. The performance of the system loaded with battery (12V/3Ah x 3 lead acid) and fluorescent lamps (T5/35W x 2) are measured. The experimental outcomes from different operation modes are found in good agreement with theoretical analysis and design. The energy efficiency of the converter when operating in charge mode is 86.63%, and operating in discharge mode is 90.26%.