Adaptive passivity-based control of a TCSC for the power system damping improvement of a PMSG based offshore wind farm

This paper proposes the adaptive passivity-based control of a thyristor controlled series capacitor (TCSC) for damping improvement of a permanent-magnet synchronous generator (PMSG) based offshore wind farm (OWF) fed to a one-machine infinite-bus (OMIB) system. The passivity-based control (PBC) is an energy-based approach whose aim is to render the closed-loop system passive with a given storage function. However, the standard PBC requires an accurate model to passivize the system, which is not realistic, in practise, as the active-power of PMSG based OWF is unknown because of the time-varying turbulent wind power inputs. By defining the system perturbation to represent the combinatorial effect of the model uncertainties and external disturbances, we designed a high-gain state and perturbation observer (HGSPO) to estimate the perturbation and angular speed, which are used as part of the adaptive passivity-based control (APBC) system. Simulation studies verify that the proposed approach can render better damping performance with only one state measurement.