We describe a multi-layer architecture for the control of variable speed wind turbines, whereby each control layer targets a specific goal. The proposed architecture is inspired by the multi-objective nature of the wind turbine control problem. Three main goals are identified and associated with three distinct control loops: a) trimming and load alleviation for large scale gusts engulfing the whole rotor disk, targeted by a collective-pitch/torque controller; b) alleviation of deterministic slowly varying and low frequency loads, targeted by a higher harmonic controller operating in the frequency domain; and c) alleviation of non-deterministic loads caused by small spatial and fast temporal wind fluctuation due to turbulence. The proposed control architecture is demonstrated by means of various tests conducted in a high-fidelity simulation environment. (C) 2012 Elsevier Ltd. All rights reserved.