Simulation of Control Characteristics of Current-Mode DC-DC Boost Converters

• Main Authors: Wallance Lin, 林俊宏
• Other Authors: 陳德玉
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/49844798338880989762

碩士 === 國立臺灣大學 === 電機工程學研究所 === 95 === There are two feedback loops, Voltage Control Loop and Current Control Loop, in Current Mode DC-DC Converter. According to Small Signal Model, two groups of Loop-gain function can be obtained, and they are T1 and T2. It can be verified by these two groups of Loop-gain function that whether the whole system is working under stable and reliable condition. In order to build up a stable and reliable system, Voltage Control Loop and Current Control Loop are essential to be understood. Hence, a reliable converter can only be hence designed through T1 and T2, together with Voltage Control Loop and Current Control Loop. In which, T2 can be easily obtained by measurement; however, T1 has yet long been obtained by any measurement or simulation. Most importantly, T1 has been the benchmark of system reliability. In recent years, many researchers make effort to use SIMPLIS software to obtain simulated T1 of Buck Converter, yet this method cannot be applied in Boost Converter since the structure of Boost Converter is different from Buck converter, let alone that Boost Converter has the feature of Position Zero. Position Zero has great influence to reliability from to view of Frequency Response. Therefore, to understand right plane Zero is important to effect of T1 and T2. This dissertation aims to make use of SIMPLIS to simulate T1 in Boost Converter and other important parameters. Then the simulation result will be cross-verified by experiments. The purpose of this dissertation is to research the accuracy of simulation result of SIMPLIS. Although by collocating mathematic equation and MATHCAD, Crossover Frequency and Phase Margin can be obtained in T1 Frequency Response, this method does not consider the influence of MOSFET Turn on Resistance, Operation Amplifier, and Delay based on the reason that mathematic equation is designed under perfect conditions. Therefore, by SIMPLIS simulation, real conditions will be considered into equation in addition to no demand of extra equation. The result is importantly beneficial to recent DC Converter development in high frequency since demand of controlling bandwidth is increasing dramatically. To conclude, this dissertation purpose is to use the change of MOSFET Turn on Resistance to examine and verify that SIMPLIS can prove the accuracy of the result made by mathematic equation and also make it convincing that Loop Gain made by SIMPLIS simulation is reliable.