Study and Implementation of a High-Efficiency Half-Bridge Series Resonant Converter with Wide Input Voltage Range

• Main Authors: Kun-Yuan Li, 李坤源
• Other Authors: Yu-Kang Lo
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/26200370702268006092

碩士 === 國立臺灣科技大學 === 電子工程系 === 97 === Based on the trend and policy of energy saving, a 240-W half-bridge (HB) series resonant converter (SRC) with wide input voltage range is presented in this thesis. The aim is to raise the light-load efficiency at high line input without affecting the heavy-load efficiency. The front-stage circuit of the implemented AC-to-DC converter is a power factor corrector (PFC) to improve the input power factor (PF) and current harmonics. The post-stage circuit is the discussed HB SRC adopting the zero-voltage-switching (ZVS) and synchronous rectification (SR) techniques to achieve high conversion efficiency. The output voltage of the presented tracking boost PFC is varied with the input AC voltage to raise the heavy-load efficiency of the post-stage HB SRC. Also the PFC is turned off below some specified load level at high line input to improve the light-load efficiency. Detailed circuit operations and design considerations are given in this thesis. A 240-W prototype converter with universal input AC voltage (115 V ~ 230 V) is built to conduct the experiments. The regulated output voltage is 12 V and nominal load current is 20 A. The switching frequency is from 45 kHz to 90 kHz. Experimental results show that the overall conversion efficiency at full load (240 W) and at low line input (115 V) is 90 %, while a 92-% efficiency is measured at light load (48 W) and at high line input (230 V).