Passivity-based control of UPFCs

We explore the passivity-based control (PBC) for robust UPFC controller design. Under this framework, the dynamical model of UPFC will be represented by a Euler-Lagrangian (EL) system with a set of EL parameters. The energy-dissipative properties of system model are fully retained. The proposed nonlinear UPFC controller consists of two feedback loops. In the inner loop, the so-called passivity controller design will be applied to regulate its reference current commands. The outer loop control is to generate the proper reference signal into the inner PBC inner controller according to the power flow requirement of the UPFC. Simulations on a simple power system demonstrate that PBC controllers can provide a performance a for regulating both power flows and AC bus voltages.