Study and Implementation of DC/AC Backup Power Supply with Fast Transfer Time

• Main Authors: Yung-Cheng Huang, 黃永政
• Other Authors: Hurng-Liahng Jou
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/50637921721669830765

碩士 === 國立高雄應用科技大學 === 電機工程系 === 98 === In this paper, a DC/AC backup power supply with fast transfer time is developed. The DC/AC backup power supply, consisted of a battery set and a DC/AC inverter, is connected to the load in parallel through a mechanical switch. When the utility is normal, the load power is supplied from the utility directly. The power stored in the battery set will be converted into an AC power by the DC/AC inverter and supplying to the load while the utility is failed. The transfer time from the utility to the DC/AC backup power supply is near zero. The salient feature of the developed method is that the output current of the DC/AC inverter is controlled to approach null when the utility is normal. Consequently, the output mechanical switch of the DC/AC inverter can be closed and no circulating current flows between the utility and the DC/AC inverter. Hence, the mechanical switch between the DC/AC inverter and the load keeps closed regardless that the utility is normal or not, so as to perform the function of null transfer time. The mechanical switch is opened only when the DC/AC inverter is failed. Finally, a digital signal processing (DSP) based prototype is developed to verify the performance of this DC/AC backup power supply. The experimental results show that the performance of this DC/AC backup power supply is as expected.