應用於太陽能照明之智慧型複合電池充電控制器設計與研製

Design and Implementation of Intelligent Composite Battery Charger for Solar Energy Lighting Systems

太陽能發電系統應用於室外照明之儲能電池，基於成本考量大部分使用傳統鉛酸電池，因此帶來許多缺點，為有效運用太陽能充放電管理應用模式，因此提出智慧型複合電池充電控制器應用於太陽能照明。當陽光強照度或大電流充電時，先以鋰鐵電池進行快速大電流充放電，除了可以解決鉛酸電池充電緩慢的缺點；並可獲得極高充放電效率；當陰天鋰鐵電池儲量不足時，切換至鉛酸電池供電，有效提供備用電源且延長陰天供電天數，大幅延長鉛酸電池壽命。此外，太陽能電池對複合電池充電，其中鋰鐵與鉛酸電池容量比例，攸關系統轉換效率，因此提出反應曲面法進行兩種電池容量比例最佳化設計。本系統控制電路採用 Microchip PIC18 系列微控制器為基礎，大幅縮小硬體電路體積，採用智慧型脈波寬度調變充電控制法針對複合電池來進行數位控制及實現控制策略，使其具有高充放電效率、維修成本低、延長陰天照明時間及環保效益等優點，也使用最大功率點追蹤法-功率回授法，使太陽能電池輸出最大功率。最後，完成一套太陽能電池輸出功率 174 W，輸出電壓12 V 之雛型硬體電路，並將所提電路實際應用於校園路牌照明，證實所提系統可行性及有效性。

Although lead-acid batteries are the most common type of energystorage for outdoor solar lighting systems, due to cost consideration, they have many disadvantages. This study proposed an intelligent compositebattery charger (ICBC) for the effective charge-discharge management ofPV modules. When the sunlight is strong, a quick charge and dischargeare achieved with lithium-ion batteries to enhance the low charge-dischargeefficiency of lead-acid batteries. By automatically switching from lithiumionbatteries to lead-acid batteries on cloudy days, the ICBC can providebackup power and extend power supply and thereby extend the lifespan ofthe lead-acid battery. As PV modules can charge the composite battery,the capacity proportion of lithium-ion and lead-acid batteries, which iscritical to system conversion efficiency, plays an important role in systemconversion efficiency. The response surface methodology was thus appliedto the optimal design of the composite battery.The system control unit was developed upon the Microchip PIC18Fmicroprocessor to significantly reduce hardware circuit dimension. Theintelligent pulse using PWM battery charging control was applied to thedigital composite control to enhance charge-discharge efficiency, lowermaintenance cost, extend lighting time on cloudy days, and maximizeenvironmental benefits. Maximum power point tracking (MPPT) was alsoemployed to maximize PV module output. A 174 W at 12 V prototype PVmodule was built. The proposed system was implemented to streetlightsand signs on campus to verify system feasibility and effectiveness.