Sliding Mode Control for PMSG-based Wind Power System

Abstract

Variable structure control has proven particularly suitable to variable speed wind energy conversion system control, being easy to implement by the already existing electronics. Its main drawback is an increase of mechanical stress due to chattering, which can however be alleviated by various methods. This paper proposes a sliding mode approach for tracking the energetic optimum of a variable speed permanent magnet synchronous generator PMSG. The sliding surface is systematically derived from imposing a desired reduced-order dynamics and allows the turbine operation more or less close to the optimal regimes characteristic, according to an imposed trade-off between the torque (control input) ripple and the optimum tracking. In this way, by torque controlling the generator, a multipurpose (energy-reliability) optimization is actually achieved.