Abstract
This thesis studies STATCOM control when an unexpected unbalanced fault is experienced in the grid. In order to extract the corresponding positive sequences and negative sequences of voltage/current phasors, both voltage/current sequence observers will be considered first. Then the controller design is based on the conventional cascaded inner/outer loop current control configuration. These control parameters must be designed precisely to meet proper bandwidth relationship among observer, inner-loop current control, and outer-loop voltage control, so that it can conform the given transient performance. In order to verify the correctness of the proposed control, dynamical simulations in SIMULINK will be investigated. Then, Matlab Embedded Coder will utilized for generating DSP codes for hardware implementations. A three-phase balanced voltage dip circuit is implemented for hardware experiments of unbalanced faults. Both simulations and experimental work are conducted. Both results provide satisfactory dynamical performances of the proposed controller.