Modeling, Analysis, and Implementation of a Power Converter with Integrated Magnetics, Low Ripple, and Parallel Configuration

本論文旨在研究直流至直流換流器的電路設計、動態模式控制及多模組操作分析，並提出一種新型具有改進鐵心結構及低漣波的推挽式換流器。首先，大部分文獻指出具有功因矯正器的直流至直流換流器都串接一個昇壓式換流器，本文發現當推挽式換流器工作週期大於50%時，可以簡化前端的昇壓式換流器，轉換成一個新型的單級換流器。其次，耦合電感的技術使用，使得換流器的尺寸及重量變小並完成輸入電流的低漣波效應。所有磁性元件包括輸入濾波電感、降壓變壓器都整合在一個EI型組合的鐵心上。又所提出的積體磁場架構具有較小漏電感及較低鐵心損失。本論文實際製作換流器的原型以做為所提理論的驗證。 最後，本論文提出推挽式換流器多模組並聯操作，在並聯工作時，使用一種主僕式電流控制技術以補償任一模組電流分流的不平衡。首先找到多模組並聯系統的小訊號等效電路及轉移函數模型，然後使用主要能量模式理論作轉移函數模型的化簡，基於簡化的換流器模型，再根據所訂定的調節規格，定量的設計PI控制器。本論文實作一個三模組的推挽式換流器並聯系統，由模擬結果及實驗波形驗證所提控制器的有效性及換流器的性能。The major purposes of this dissertation are to perform circuit design, dynamic modeling, control and multi-module operation analysis for DC-DC converters. This dissertation presents a novel single stage push-pull boost converter with a improved integrated magnetics and ripple-free input current. First, most of the reported single-stage power factor corrected (PFC) rectifiers cascade a boost-type converter with DC-DC converter. It is found that the push-pull converter with the duty cycles greater than 50% can simplify the front of boost-type converter to a novel single stage converter. Secondly, coupled inductor techniques provide a method to reduce the converter size and weight, and achieve low ripple current. All the magnetic components including input filter inductor and step-down transformer are integrated into a single EI core. The proposed integrated magnetics structure has a simple core structure, a small leakage inductance and low core losses. The prototype is built to demonstrate the theoretical prediction. Finally, the design and implementation of a multi-module parallel push-pull converter system is presented. In parallel operations, a master-slave current control technique is proposed to compensate the mismatch in current control characteristics of each parallel converter. The small-signal equivalent circuit and transfer function model of the multi-module converter system are found. Then the model reductions are performed using the concept of dominant energy mode. Based on the reduced converter model, a PI controller is quantitatively designed according to the prescribed regulating specifications. A three-module control scheme is proposed. The performance of the converter and the effectiveness of the proposed controller are demonstrated by some simulation and experimental results.中文摘要 ………………………..……………………………………Ⅰ ABSTRACT …………………………………………….………………………..Ⅱ CONTENTS ………………………………………………..……………………Ⅳ LIST OF FIGURES ………………………….……………..……………………Ⅵ LIST OF TABLES ..…………………………..………….………………………Ⅸ CHAPTER 1. INTRODUCTION ………………….………………..…………..1 1.1 Motivation ……………………………………………………………1 1.2 Literature Survey …….………………...…………………………….2 1.3 Contribution of This Dissertation ………...………………………….5 1.4 Organization of This Dissertation ……………...…………………….6 CHAPTER 2. PRELIMINARIES ………..…………….……………………7 2.1 Single Stage Converter ………………………...……………………7 2.2 Zero-Ripple Phenomenon ………………………………………….10 2.3 Integrated Magnetics ……………………………………………..13 CHAPTER 3. NEW PUSH-PULL BOOST CONVERTER DESIGN …...…..…18 3.1 Configuration ……………………………….…………………….19 3.2 Steady State Analysis ………………………………………………24 3.3 Integrated Magnetics ………..………………………………………28 3.3.1 Derivation of the Integrated Magnetics ……...………………….28 3.3.2 Electrical Model ………………………………………..………30 3.3.3 Design of the Proposed Transformer …….………….…………34 3.3.4 Numerical Simulation Results ………………………………....38 3.4 Experiment Results …………………….…………………………..40 3.5 VRM Applications …………………………….………………………49 3.5.1 Introduction …………………………………………………….49 3.5.2 Configuration of the Proposed Topology ………………………50 3.5.3 Analysis of the Proposed Topology ……………………………52 3.5.4 Verification ……………………………………………………..56 CHAPTER 4. DYNAMIC MODELLING OF PARALLEL CONVERTERS …58 4.1 Parallel Configurations ………..…………….…..…………………..60 4.2 Small-Signal Model ….………………….……..…………………..60 4.3 Open-Loop Analysis …………..………...……..…………………..64 4.4 Model Simplification .………..……..……..……………………….68 4.5 Simulation Results ……….…………………..…………………….73 CHAPTER 5. DESIGN OF PARALLEL CONVERTER SYSTEMS …..……74 5.1 Parallel Configuration Without Inner-Loop Current Control …..…...75 5.2 Parallel Configuration With Inner-Loop Current Control ……...…….80 5.3 Design of Input Voltage Feed-Forward Controller ….….………….84 5.4 Experiment Results …………..…………………………………….86 CHAPTER 6. CONCLUSIONS ……..………….……….………………….92 6.1 Conclusions ……………………….………………………………..92 6.2 Future Work …………………...………….………………………..93 REFERENCES ………………………………………………………………..9