Zero-Current-Switching Buck Converter for Battery Chargers

• Main Authors: Li-Hsiung Hsieh, 謝禮雄
• Other Authors: Jung-Chien Li
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/54900046370594056741

碩士 === 國立臺灣海洋大學 === 電機工程學系 === 100 === The resonant converter provides the advantages of low switching losses, small circuit volume, light weight and high power density. Various high-frequency switching converters have replaced traditional hard -switching converters. This thesis presents zero-current-switching buck converter for battery chargers to control resonant converters flexibly. An auxiliary switch is inserted into the resonant loop in the proposed battery charger to control the resonant time precisely. The developed charger has the advantages of the hard-switching converter and the resonant converter with constant -frequency control, reduced resonant time and the operation of all switching components in the charger under the zero-current-switching condition to reduce significantly the switching losses. The developed charger circuit is highly suitable for high-frequency operation and high charging efficiency. This thesis employs the control mode for the switching of two active switches. The operation modes of the circuit and the equivalent circuits are constructed by analyzing the operating principles of the circuit, based on the turn-on conditions of the active switches. The equations used to determine the circuit parameters are derived from the equivalent circuits. Experimental results have demonstrated the theoretical effectiveness of the proposed battery charger circuit. A practical mean charging efficiency of over 90% is obtained.