新式3階段切換技術應用於直流/直流轉換器及直流/交流變流器之設計

Abstract

本文提出一含新式共振式輔助電路的3階層(three-level)轉換器，並將之應用於半橋式直流轉換器。其架構包括共振電容、可應用於雙向迴路的共振電感與開關的組合電路，不僅可以提供導通時零電壓切換損失，亦可達到中性點箝制功能，避免因開關截止時變壓器漏感與開關寄生電容所造成的震盪。本輔助電路可分別應用於零電壓切換半橋式直流轉換器及變流器的工作模式。3階層轉換器應用於變流器時，可使原本輸出波形由高電壓的切換，進而轉變為原來一半電壓的切換。不僅降低了電感上的連波電流，同時電晶體的耐壓可降至直流鏈電壓的一半。為了驗證本設計，一12V/10A, 120 W的半橋式直流轉換器已實做出來。在各項包括負載變動的模擬和實驗下，結果顯示了開關工作時的電壓電流皆與設計規格符合。

A new 3 level auxiliary circuit applicable to converters and inverters is proposed. The auxiliary circuit includes resonant capacitor, resonant inductor and bi-direction switch. This circuit can provide the natural clamp to eliminate oscillation from the leakage inductance of transformer and the soft switching function to both half-bridge converters and inverters. At the same time the switch can operate with zero-voltage switching while turning on. Furthermore, this circuit also provides the function to reduce half of the voltage stress of switch on the inverter application. The proposed circuit was identified with 12V/10A, 120W DC to DC converter and inverter application.