高效率串聯負載共振式太陽能蓄電池充電器之研製

Design and Implementation of High-Efficiency Battery Charger with Series-Loaded Resonant Converter for Solar Energy Applications

陳宏昆(Hung-Kun Chen)

指導教授 ： 莊英俊

崑山科技大學/工程學院/電機工程研究所/碩士(2007年)

摘要

石化燃料並非取之不盡的能源。人類大量地使用石化燃料造成二氧化碳排放量的增加，間接造成了溫室效應以及產生了大量的熱汙染，並且也加劇了全球氣溫上升與氣候的變化。因此，我們呼籲政府促進節能，提升能源效率，並且發展可再生之能源，如：太陽能、風力、潮汐、生質能、地熱、氫能、海洋溫差之產生...等等各種再生能源。台灣位居於亞熱帶並鄰近赤道，日照量相當充裕且日照時間又長，因此太陽能為一最沒有污染之能源，而蓄電池充電器則是太陽能發電系統中不可或缺之裝置。
由於共振式轉換器電路架構之優點眾所皆知，其具有簡單的控制結構，低切換損失以及低電磁干擾(EMI)...等各項優點。除此之外共振式轉換器已獲得越來越多的關注，特別是操作於高切換頻率時，應必須獲得高功率之輸出。爲了改善傳統切換式充電器電路之性能，本論文提出ㄧ高效率串聯負載共振式太陽能蓄電池充電器，且此充電器之切換頻率可以控制在小於或大於共振頻率。如此ㄧ來，根據切換頻率與共振頻率間之比例，此充電器電路可能具有三種不同的操作模式。藉由縝密地設計電路各元件上之參數值，此共振式蓄電池充電器會被操作於不連續電流模式或連續電流模式兩種模式其中之一。因此，本文所提之共振式蓄電池充電器之充電電流與充電時間是可以控制的。
本論文根據開關切換時情況配合輸出濾波器電路結構，建立出整體等效電路的工作模式，並加以分析其操作原理，撰寫電路各特性方程式。本文使用基本波近似法與蓄電池簡化等效電路以簡化電路分析，建立串聯負載共振式充電器之等效電路，並以此等效電路為基礎，推導電路參數設計方式及電路設計流程。然後以電腦模擬與實作電路做理論驗證，實驗結果令人相當滿意。最後，本篇論文為了在短時間內，更有效的儲存太陽能光電模組所產生的電力，減少蓄電池充電時間，提出一改良型的串聯負載共振式蓄電池充電器，此種新型的蓄電池充電器，不僅能大幅地提升充電電流，降低蓄電池充電所需的時間，其充電效率更高達87.5%以上。

關鍵字

充電器 ； 共振式轉換器 ； 光伏電模組

並列摘要

Fossil fuel is not sustainable. The use of fossil energy will increase the emissions of carbon dioxide (CO2), produce greenhouse effect indirectly, and also release huge waste heat, and hence will aggravate the global warming and climate change. Therefore, we urge the government to promote energy conservation, enhance energy efficiency, and develop renewable energies (solar, wind, micro-hydraulic, biomass, geothermal, hydrogen, and ocean). Taiwan is located in the subtropical zone, with lots of sunlight and long sunny days. Solar energy should be the most prominent candidate for clean energy. A battery charger is an indispensable equipment for solar power generation systems.
Due to the well-known advantages of resonant converters such as simple circuit configuration, easy control scheme, low switching losses, and low electromagnetic interference (EMI), etc, the resonant converters have gained more and more interests, especially when the switching frequency must be very high to get high power density. To improve the performance of traditional switching-mode charger circuits, a high-efficiency battery charger with series-loaded resonant converter for solar energy applications is presented in this paper. The switching frequency can be controlled to be less than or greater than the resonant frequency. Thus, there are three possible operating conditions based on the ratio of switching frequency to the resonant frequency. With carefully designed circuit parameters, the resonant battery charger can be operated at either discontinuous conduction mode (DCM) or continuous conduction mode (CCM). Then, the charging current and charging time can be controlled.
Circuit operation modes are identified according to the conduction profiles. Operation equations and operation theory are also developed. This paper applies fundamental wave approximation and battery equivalent circuit to simplify the circuit analyses. The circuit is approved by computer simulation and experiments. In order to efficiently store enough power into the photovoltaic modules in short period, this paper proposed a new series-loaded resonant battery charger. This new battery charger can provide high charging current and reduce the charging time. The charging efficiency of the proposed topology is as high as 87.5%.

並列關鍵字

Battery charger ； Resonant Converter ； Solar energy

參考文獻

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