電壓源轉換器(voltage source converter, VSC)已被廣泛用於現代電力系統中，因為它們是柔性交流輸電系統（FACTS）、HVDC及分散式發電機與電網連接的組件。而在所有類型的轉換器中，模組化多階層轉換器(modular multilevel controller, MMC)因其模組化的特性，已被廣泛運用在研究及商業應用中。
在眾多的MMC控制中，傳統的比例積分及比例共振控制器已達成需求，但因電力系統具有許多不確定性，如電網參數影響等，為了解決此問題，許多非線性控制器已被提出，例如：模型預測控制(model predictive control, MPC)及滑動模式控制(sliding mode control, SMC)。
在本文中，我們提出一種將SMC滑動面相結合的新型滑動面。本文將所提控制器與比例積分控制器在離線與硬體迴路(hardware-in-the-loop, HIL)中實現。當受參數不確定性影響時，與傳統比例積分控制器相比，所提控制器結果更為出色。

Voltages source converters are widely used in the modern power system as they are the main building blocks for the Flexible AC Transmission System (FACTS) devices, HVDC, and the grid-interfacer for distributed generators. Amount all types of converters, the modular multilevel converter (MMC) has been widely used in research and commercial areas due to its modular characteristics.

For the MMC controls, the traditional proportional integral and proportional resonant controllers have been successfully implemented. However, they are unable to handle MMC, subjected to parameter uncertainties, such as impedance parameter change, grid parameters variation, etc. To overcome this problem, various nonlinear controllers have been proposed, e.g. model predictive control (MPC) and sliding mode control (SMC).

In this thesis, we have proposed a new sliding surface which combines SMC with integral surface. The proposed method are both implemented in off-line and hardware-in-the-loop (HIL) simulation. The control results as compare to those based on PI control are superior, when subjected to various parameter uncertainty conditions.

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