Flatness-based adaptive control (FBAC) for STATCOM

This article proposes a new method, called the flatness-based adaptive control (FBAC), for STATCOM voltage regulation. By this method, the nonlinear STATCOM variables can be easily and exactly controlled by controlling flat output without solving differential equations. Further, the control gains can dynamically self-adjust during the voltage regulation after a disturbance. Thus, the performance from FBAC will consistently match a desired response, regardless of the change of operating conditions. In contrast, the traditional PI control and the flatness-based control (FBC), even if well-tuned for a specific given operating condition, may be inefficient or incapable to correct voltage when there is a change of the operating conditions or the STATCOM is deployed in a new power system. The advantage of the proposed FBAC over the traditional PI control and FBC control is demonstrated with the simulation studies under different operating conditions, such as a change of network and a change of load.