The State-Space Modeling and Nonlinear Control Strategies of Multilevel DSTATCOM

The modeling and implementation of a nonlinear control strategy for three-phase four-wire multilevel distribution static compensators (DSTATCOM) was presented in this paper. The nonlinear state-space model of the multilevel DSTATCOM was obtained from the dq0 reference frame. The input/output feedback linearization was then applied and the state feedback linearization control law was derived. The obtained model was linearized and decoupled in three independent subsystems. The stabilizing controllers were designed based on linear method to quickly adapt to various changes in load. The simulation was performed by PSCAD/EMTP. The system performance was tested through changing the load from resistance to non-linear and also from inductive to capacitive. The results shown that the DSTATCOM nonlinear control system could adapt to load changes and have effective steady-state compensation and a better dynamic response.