Study on the internal mode control of three-level STATCOM

When the static synchronous compensator (STATCOM) is used for grid dynamic compensation, reactive current detection aspects and current controller design play a decisive role. This paper, on the basis of the traditional FBD power theory, proposes an improved FBD detection method, and introduces the grid virtual flux mode observer to replace the original phase-locked loop to reconstruct the grid voltage, which improves the ability of detecting reactive current when grid voltage distortion occurs; at the same time, the inertial link is used to replace a low-pass filter to reduce the delay of the detection system. Considering the characteristics of nonlinear and strong coupling of static synchronous compensator, this paper proposes a current decoupling control method based on the internal model control principle and three-level space vector algorithm. Based on the basic principles of the internal model control, the double closed loop internal mode controller is designed for the static synchronous compensator. Ba