Design of an LLC Resonant Converter Based on Efficiency and Switching Frequency Variation Range

• Main Authors: LI,HSI-SHUN, 李錫順
• Other Authors: CHANGCHIEN,SHIH-KUN
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/77757805518878833237

碩士 === 建國科技大學 === 電機工程系暨研究所 === 104 === This thesis proposes a Q value determination approach for LLC resonant converters based on the considerations of efficiency and switching frequency variation range. LLC resonant converter is widely used in many applications of power conversion due to its high efficiency and low switching noise. The determination of Q value is a key point for the design of LLC resonant converters in practice. In addition, as a rule of thumb of the peers, Q value of LLC resonant converters is usually set within a reasonable range without theory analysis and derivation in detail. Therefore, a Q value determination method of LLC resonant converters is proposed in this thesis based on efficiency and switching frequency variation range. Firstly, in order to obtain the equations between voltage gain, efficiency and Q value, the circuit analysis of LLC resonant converters is presented. Then according to the equations, change Q value to get the voltage gain and efficiency variation data, and using normalization and curve fitting techniques in these data, the Q value is determined. Finally, a prototype with 380 V input and 24 V/240 W output LLC resonant converters, is implemented to estimate the feasibility of the proposed Q value determination approach. The experiment from 6 resonant tanks of different Q value of the theoretical and experimental detailed data are presented to prove its achievement. The experiment proved that the proposed Q value determination approach is efficiency.