Design of STATCOM damping control with multiple operating points: a multimodel LMI approach

A damping control design for electric power systems with multiple operating points is discussed. The damping control design problem of a multimodel system can be described by nonlinear matrix inequalities (NMI). In the past, LMI approaches have been proposed to solve the damping control design on a nominal model (or single model) through suitable parameterisation and transformation of the original NMI into LMI problems. However, nominal model based LMI approaches and associated parameterisation and transformation techniques are not applicable to the NMI for a multimodel system. A two-step based LMI approach for output feedback damping control design for a system with multiple operating points or a multimodel system is presented, applicable to a general linear model with matrices (A, B, C, D). In particular, the incorporation of regional pole placement in a STATCOM damping controller for a multimodel system is presented and damping control design is demonstrated on both a single-machine infinite bus and a multimachine power system. Numerical results show the proposed damping controller can ensure simultaneous stability and adequate damping for multiple operating points.