Maximum power tracking of direct-driven WEC based on input saturation <i>L</i> ₁ adaptive control

For the direct-driven wave energy converters (WEC) with time-varying disturbance and uncertain parameters of model, a maximum wave energy capture strategy based on input saturation L 1 adaptive control is proposed. By analyzing the hydrodynamic model of a direct-drive WEC and the mathematical model of permanent magnet linear synchronous generator (PMLSG), a state-space model of the direct-drive WEC is established; the maximum power capture condition is obtained by using the equivalent circuit method; the input saturation L 1 adaptive controller with µ-modification is designed considering the controller limited case, which can effectively suppress the effects of time-varying disturbances and uncertain parameters of model to make the system track the desired current, and then achieve the maximum power tracking control. The convergence proof of the observation and reference errors is given. Simulations verify the effectiveness of the proposed control strategy, and the system has good steady state tracking performance and transient performance.