Study on the Asymmetric One-Sided Duty Cycle Modulation Strategy for Half-Bridge Series Resonant Converters Operating at Light Loads

• Main Authors: Cho-Wen Huang, 黃卓文
• Other Authors: Yu-kang Lo
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/65184303949082566104

碩士 === 國立臺灣科技大學 === 電子工程系 === 97 === This thesis is devoted to design an AC-to-DC adaptor for raising the conversion efficiency of a DC-to-DC series resonant converter (SRC) and decreasing the power loss at light-load condition. The front-end part of the adaptor is an active power factor correction circuit to improve the input power factor. The second stage is a half-bridge series resonant converter that utilizes zero–voltage switching and synchronous rectification to achieve high conversion efficiency. The low power consumption at the light-load condition is obtained by using the proposed asymmetric one-sided duty cycle modulation control method. One of the two power switches in the half-bridge SRC features the zero-voltage turn-on at light load. The comparisons will be made between the proposed controller and the commercial IC CM6900. Experimental results are recorded for a prototype converter with an AC input voltage rang from 115 to 230V, an output voltage of 12 V and an output current of 20 A, operating at switching frequency from 50 kHz to 150 kHz.