Study on high efficient isolated DC/DC converters with hold-up time compensation technique

Abstract

Global oil price has been continuously increased in last few decades and greenhouse effect caused by carbon dioxide emission becomes getting more serious in these days. It causes climate changes in all around the world and many countries are currently suffered from unusual natural disasters, hurricane, tsunami, flood, drought …and so on. To solve this problem or slow down the process of climate change, many researches have been performed to improve the efficiency over the entire industries and special attention is drawn to transportation industry and IT industry which are major oil consuming industries. Especially, IT industry shows rapid growth in recent years followed by the development of internet infrastructure and it becomes the second largest oil consuming industry in these days. Many regulations have been made to restrict the oil consumption in IT devices and they set up energy efficiency standards for every IT device to promote the researches for the products with high efficiency. In this dissertation, three different topologies will be presented for high efficiency IT devices. Each topology is focusing on three different power levels, high power level, middle power level and low power level. High power level represents beyond 1kW level, middle power level indicates between 400W and 1kW power level, and low power level shows under 400W power level. Also the researches include hold-up time compensation technique which becomes the essential requirement in IT devices. The meaning of hold-up time is explained in main section and high efficient topologies having hold-up time compensation technique is proposed. The researches for high power and middle power levels are targeting on server power system specification and those for low power level are targeting on 75W LED TV specifications. The two stage type power structure is adopted as the basic power conversion structure. This system composed of PFC stage and DC/DC stage. The output voltage is regulated in...