Expansion of system operating range by an interpolated LPV FACTS controller using multiple Lyapunov functions

In this paper, a new gain-scheduling control design approach is applied to a supplementary damping controller (SDC) design for a FACTS device in the IEEE 50-machine system. The power system model with the FACTS device is linearized at different operating points to obtain an LPV open-loop model, whose state-space entries depend continuously on a time-varying parameter vector. A synthesis procedure for an improved LPV controller using multiple parameter-dependent Lyapunov functions and an interpolation scheme is presented and applied to the static VAr compensator (SVC) SDC design. Comparisons from simulation results are presented among the interpolated LPV controller designed using multiple parameter-dependent Lyapunov functions (MLPV SDC), the LPV controller designed using a single parameter-dependent Lyapunov function (SLPV SDC), and a conventional controller designed using the Root-locus method (RL SDC), which show that with an interpolated MLPV SDC for the SVC device, the system can achieve better robustness in an extended operating range.