高功率轉換器系統通常在低開關頻率下工作，以減少半導體開關的開關損耗。然而，目前的一些控制和調製方法皆是針對高頻率切換的低壓功率轉換器而設計的，故用於高功率轉換器時，可能產生誤差或達不到控制目的。本文提出了一種基於擬似牛頓疊代控制演算的新型控制方法，適用於低開關頻率下，仍能實現期望的控制目標。本論文以靜態同步補償器(STATCOM)為例，實現所提控制法則，在平衡與不平衡，二級或多級的電壓源換流器中，透過離線PSCAD / EMTDC與RSCAD即時模擬，以驗證可行性。

High power converter systems are usually operated at low switching frequencies to minimize the switching losses of the semiconductor switches. However, some of control and modulation methods used today may not work well for high power converter system. Therefore, errors may occur or control objectives may not be achieved. This paper presents a novel control method based on Quasi Newton iterative control algorithm, which is able to achieve the desired control objective with low switching frequencies. In this thesis, we implement the proposed control law in the static synchronous compensator (STATCOM) with the balanced and unbalanced, two-level or multi-stage voltage source converters. The validity of the proposed method has been verified by the offline simulation via PSCAD/EMTDC and RTDS.

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