Modeling and Design of a Novel High Step-up Ratio Interleaved DC Converter

• Main Authors: Liu, Wei-Chih, 劉威志
• Other Authors: Pan, Ching-Tsai
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/81828430330752169081

碩士 === 國立清華大學 === 電機工程學系 === 97 === Recently, due to the global energy shortage and global warming effects,many countries are actively promoting the developing clean distributed energy sources such as fuel cells and photovoltaic systems. However, the output voltage of solar cells and fuel cells is rather low and a high step-up dc converter is normally required as an interface for back-end applications. Therefore, the objective of this thesis is focused on developing a high efficiency high step-up dc converter for these two new energy systems. Basically, the major contributions of this thesis can be summerized as follows.First, a novel high efficiency and high step-up dc converter is proposed. Through the new topology, the voltage stress of both active switches and diodes are greatly reduced so that lower on-resistance switches can be adopted and less reverse recovery effect of diodes will be induced. Also, the interleaved configuration will not only reduce the input current ripple but also further increase the system efficiency. Second, both DC and small signal models of the proposed converter are derived for better closed loop control. In addition, some design guidelines are given for convenient implemention. Finally, a 20V input 400V output prototype with 300W rating is also constructed. It is seen that the voltage stress of the active switches and the diodes are equal to one eighth and half of the output voltage respectively and the resulting system efficiency can be maintained above 90% as the load is varied from 60W to 260W. In fact, the highest efficiency is 94%. Both simulation and experimental results indeed verify the effectiveness of the proposed converter.