Optimization‐based load reduction during rapid shutdown of multi‐megawatt wind turbine generators

Abstract

This paper describes an optimization-based approach to reducing extreme structural loads during rapid or emergency shutdown of multi-megawatt wind turbine generators. The load reduction problem is cast into an optimal control formulation, and a simple, low-order model is developed in order for this optimization problem to be tractable in reasonable time using state-of-the-art numerical methods. To handle the variations in wind speed and turbulence inherent to wind turbine operation as well as the presence of model mismatch, a real-time optimization strategy based on fast sensitivity updates is also considered, whose on-line computational burden is limited to the repeated solution of quadratic programs that are designed off-line. The low-order model and both the open-loop and closed-loop optimal control strategies are validated against a high-fidelity model in the simulation environment Bladed ™ for an industrial 3MW wind turbine. Under favorable shut-down scenarios, i.e. when the wind turbine is operating properly and the actuators and sensors are not faulty, large reductions of the first compressive peak and subsequent compressive/tensile peaks of the tower load pattern are obtained at various above-rated wind speeds compared to normal pitch control shutdown. Extension to more challenging shut-down scenarios are also discussed.

A Comparative Study of Shutdown Procedures on the Dynamic Responses of Wind Turbines

“…The results of this study will aid in the structural design of wind turbine components and in the development of advanced control methods [16] to achieve load reduction.…”

New approach for optimizing energy by adjusting the trade-off coefficient in wind turbines

“…Among the recent new works in this area, it is preferred to emphasize not only on an optimization-based approach to reduce extreme structural loads during rapid and emergency shutdown [9], but also on predicting the maximum generation capacity to obtain power control [10] and extreme seeking to perform maximum point tracking [11] as well dynamic responses of land-based and floating wind turbines under pitch system faults [12].…”