Abstract
混合共振式換流器兼具純串聯式及純並聯式之主要特徵，而免除兩者之主要缺點，於大範圍之輸入電壓及負載變動下，仍保有良好之操作特性。本論文之主要目的在於探討混合共振式換流器之直流分析、電路元件設計、動態模式建立及控制器之設計等。首先，詳細分析此換流器於連續導通模式及不連續導通模式之穩態特性，並將換流器之轉換比及元件應力與正規化切換頻率間之關係表示於輸出平面上。據此直流分析結果，擬出一套共振槽路元件之簡易設計步驟。為使換流器具有良好之電壓動態響應特性，迴授控制是不可或缺的，而欲作成功之迴授控制，受控換流器之直流分析、小訊號分析及控制器之設計等步驟均不可免。而在設計控制器時，必須有適當的換流器動態模式。然由於換流器切換頻率和共振頻率相去不遠，使得狀態平均技巧不能直接運用於動態模式之建立。本文提出一個一般化小訊號分析步驟，以電路操作波形擾動為出發點，將共振槽路以差分狀態取樣模式化後，以低頻連續時間模式近似，再結合濾波器及負載部份，形成整個換流器之小訊號模式，並據以推得轉移函數模型，此模式之有效性以HP3563A 量得實際電路之頻率響應特性與模擬所得者比較加以驗證。根據系統的轉移函數模型，本論文提出一套系統化設計步驟，由所預定之動態響應規格，定量地設計出控制器之參數。所提換流器之性能及設計步驟之有效性將以一些實測結果予以驗證。It is shown that the hybrid resonant converters preservemost of the advantages possessed by series and parallelconverters, while remove their major disadvant- ages. They cannormally operate under large input voltage and load variations.Hence the hybrid resonant converters have been used in thepower supplies of many applications, e.g., the personalcomputer, space station, mobile ser- vicing system and pulseload. In this thesis, the dc analysis, circuit design,dynamic modelling and control- ler design of hybrid resonantconverters are presented. First, the dc analyses of theconverter both in discont- inuous mode and continuous modeare carried out. By plotting the relationships between theconverter gain as well as the component stresses and thenormalized switching frequency on the output plane, the steady-state characteristics of converter can be clearly observed.Based on the results of DC analysis, a systematic proce- durefor designing the resonant tank elements is then proposed.The dynamic model is indispensable for feedback control design.Unfortunately, the well-known conventional state spaceaveraging technique can not be directly used to perform itsdynamic modelling, since generally, the switching frequencyis the same order as the resonant frequency of the resonanttank. In the thesis, the dyna- mic modelling of the hybridresonant converter is also presented. In the proposedapproach, the tank circuit is first represented by a simpled-data model, and then it is approximated by a low frequencycontinuous time model. By combining other components in theconverter, a compl- ete small signal circuit model and thusits equivalent transfer function model are obtainted.According to which, a design procedure is developed toquantatively and systematically find the parameters of PIcontroller. The performance of the proposed design approach aredemo- strated by some experimental results.