本文提出一新型線互動式不斷電電源供應器，其系統是由全橋式整流器、電壓源換流器、串聯變壓器及雙向昇降壓轉換器所組成。其中全橋整流器將輸入的交流電壓轉換為直流電壓，此直流電壓不僅可對電池組作定電壓充電之外，也可透過換流器轉換成交流電壓後提供給低頻串聯變壓器。而串聯變壓器則能補償市電的各種異常情況以達到額定輸出電壓。本文將針對系統操作在不同模式下的情形做分析說明，當市電正常時，雙向昇降轉換器將被控制成一降壓轉換器，對蓄電池做定電壓方式充電；而當市電中斷時，轉換器則被控制成一昇壓轉換器，提供直流匯流排電壓給予換流器作轉換。此特性將使轉換器針對不同操作模式，扮演充電器或昇壓轉換器的角色。此外本系統採用積分比例控制器使系統的暫態響應能夠擁有無穩態誤差、無超越量和上升時間可設計等優點。最後以模擬與實驗結果來驗證系統性能。 This paper presents a novel line-interactive uninterruptible power supply (UPS) system. The proposed system is composed of a full bridge rectifier, a voltage source inverter (VSI), a series transformer and a bidirectional buck boost converter. The full-bridge rectifier transforms the AC input voltage into DC voltage. This DC voltage can not only charge the battery by means of constant voltage charging method (CVCM) but also provide AC voltage to the series transformer through the DC/AC inverter. Meanwhile, the series transformer compensates the utility variations to satisfy the rating voltage. Analysis of the proposed system while it is operated in different modes is presented. The converter serves as a buck converter to charge the battery when the utility is normal and it turns into a boost converter to supply the emergency power to the VSI when the utility fails. This bidirectional feature of the converter allows system to act as automatic voltage regulator (AVR)/ battery charger or backup power source in different operation modes. An integral proportional (IP) controller is adopted to improve the transient response of the system. Simulation and experimental results are presented to verify the performance of system.
