Trade-Off Between Energy Capture and Dynamic Loads in Variable Speed Wind Turbines

Abstract

This paper investigates the trade-off between the objectives of generating maximum power and minimizing the dynamic loads of a variable speed wind tumine operated below rated wind speed. Linear quadratic optimal control methods are used to investigate this balance. Four models of different complexity are compared, and established to have similar behaviour. The controllers have been simulated with a non-linear aerodynamic torque model, and the simulation confirmed the predicted characteristics. It is also shown that the systems are robust to parameter changes, even when the model used in the controller design is of lower order than the true system.