LLC諧振轉換器高效率設計

Abstract

LLC諧振轉換器之控制電路具有固定責任週期的優點，並利用主變壓器一次側漏電感、激磁電感、MOSFET之寄生元件及諧振電容產生諧振現象，可降低切換損失並且提高效率。本實驗電路為115V ~ 264Vac輸入，19V/4.73A輸出，轉換器在滿載狀況下可達到95.31%的效率。 本篇論文在研究LLC諧振轉換器之設計及製造加以探討並實際量測。LLC諧振轉換器具有架構簡單、體積小，不須附加元件，並利用寄生元件及諧振零電壓切換技術，減少寄生元件引起的不良效應，使開關元件具有零電壓導通切換特性，降低開關元件切換應力，使其在頻率高頻操作時仍可正常操作。

The LLC resonant converter has the merit of fixed duty cycle operation. A combination of parasitic components, which includes the MOSFET output capacitance and the leakage inductance of the isolation transformer, produces a resonant action and reduces drain-source voltage prior to turn-on. Moreover, the switching loss is reduced relatively.Therefore, high efficiency operation of system is achieved.An experimental prototype of 115~264Vac input, 19V/4.73A output, the resonant converter full load efficient reaches 95.31%. The subject of this thesis is to analyze and design a LLC resonant converter. The LLC resonant converter allows zero voltage turn-on of switches while retaining the merits of simple circuit designed and low stresses accompanied with variable frequency control. The LLC resonant converter uses parasitic components to resonate. Therefore, additional resonant components are not required. Moreover, the switching stresses are reduced by using of the zero voltage switching (ZVS) resonant technique.