商用直流分散式電壓源系統之小信號穩定度分析

Abstract

現行的直流對直流分散式電壓源系統(DC-DC Distributed Power System, DC-DC DPS)所廣泛使用的中轉排線架構(Intermediate Bus Architecture, IBA)由中轉母線轉換器(Bus Converter, BC)與多個負載點轉換器(point-of-loads, POLs)掛載其後所組成。IBA架構在整合上最大的問題在於當電壓源子系統(BC)與負載子系統(POLs)在整合後阻抗會彼此干擾並造成系統穩定度與效能的衰減，而在之前的研究發現，透過比較電壓源的輸出阻抗與負載的輸入阻抗則可避免影響系統穩定度與減輕系統間相互干擾的問題。所以在設計之初必需將個別系統的阻抗加以詳細分析。 本篇論文以商用的IBA架構掛載多個POLs與POLs不同的輸出做探討。利用POLs閉迴路輸入阻抗的特性區間，配合奈氏穩定度準則來建立電壓源子系統輸出阻抗在不同區間內與負載子系統輸入阻抗的交疊限制，以確保IBA系統在安全的穩定度範圍以內。電路的實測與數學小信號模擬亦獲得比較驗證。

An intermediate bus architecture (IBA), consisting of a bus converter (BC) and point of loads (POLs), has become very popular in dc-dc distributed power system applications. When a BC modules are connected with POLs, system interactions may cause system instability or performance degradation. It was previously reported that by comparing the output impedance of the source impedance and the input impedance of a single POL, one can avoid system instability and alleviate potential performance degradation. Therefore impedance of individual subsystems must be analyzed carefully before the system coordinated. In this thesis, this theory was applied to a commercial IBA with multiple POLs. Impedance characteristics of POL section and BC modules were used with Nyquist theorem to define the limitation of impedances and ensure the IBA system stability margin. Test results and mathematical calculations were compared with good agreement.