Sliding mode control for LVRT of a PMSG wind turbine using stored energy in rotor inertia

Abstract

This paper proposes a sliding mode controller for a permanent-magnet synchronous generator wind turbine system to satisfy low voltage ride through requirement. The generator-side converter regulates the DC link voltage instead of grid-side converter. The generator-side controller is designed using the sliding mode control considering the nonlinear relationship between the generator power and the dc-link voltage. The grid-side converter controls the grid active power to extract maximum power. The proposed control method enables regulating the DC link voltage by storing the surplus energy in the rotor inertia when a grid fault occurs. Finally, the proposed control method is validated through the numerical simulations with a topological wind turbine model. The simulation results show that the proposed method has faster conversion and smaller amplitude of oscillation than the conventional PI control.