Study on a Frequency Modulation Strategy for Series Resonant Converters with a Secondary-Side Resonant Tank

• Main Authors: Chien-yu Chen, 陳建宇
• Other Authors: Yu-kang Lo
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/60695625737638955092

碩士 === 國立臺灣科技大學 === 電子工程系 === 98 === This thesis focuses on the study and implementation of a 500-W series resonant converter (SRC) with a secondary-side resonant tank. The SRC with secondary-side resonant tank is suitable for low input voltage and high output voltage applications. The zero current switching can be easy to achieve because the primary switch current is high. When the SRC is operated at light load condition, its output voltage can’t be regulated well because the switching frequency is always less than the resonant frequency. This thesis aims to analyze the operating principle and derive the mathematic model for the studied series resonant converter with a secondary-side resonant tank. By using the simulation software Mathcad, the relationship between gain functions and quality factor is analyzed and discussed. A frequency modulation strategy is also used to regulate the output voltage. Finally, a laboratory prototype with 12V input and 200V output was built and tested to verify the feasibility of the proposed scheme, a commercial IC CM6900 with a simple auxiliary circuit was used to realize the studied control strategy. Good voltage regulation feature can be achieved according to the experimental results of the prototype circuit.