Robust Control Of An Autonomous Wind Power System

Abstract

The paper deals with the robust control of wind power systems that uses a variable
speed fixed pitch horizontal axis wind turbine (HAWT), driving a permanent magnet synchronous
generator (PMSG) connected to a isolated local grid. In such wind power systems, the control
problem consists in maximizing the energy captured from the wind for varying wind speeds. The
paper focuses on the HAWT PMSG power system modelling and dynamical analysis of the
linearized system in various operating points on the characteristic of optimal regimes. This
analysis revealed that the system is resonant and the natural frequency as well as the damping
factor of the complex conjugated pole pair varies significantly along the operating point. In those
conditions, the Quantitative Feedback Theory (QFT) method was used to design a control system
for the autonomous wind power system. The resulted robust control structure is validated by
numerical simulation.