Preview predictive control layer design based upon known wind turbine blade‐pitch controllers

Abstract

ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. ABSTRACTThe use of upstream wind measurements has motivated the development of blade-pitch preview controllers to improve rotor speed tracking and structural load reduction beyond that achievable via conventional feedback control. Such preview controllers, typically based upon model predictive control (MPC) for its constraint handling properties, alter the closedloop dynamics of the existing blade-pitch feedback control system. This can result in a deterioration of the robustness properties and performance of the existing feedback control system. Furthermore, performance gains from utilising the upcoming real-time measurements cannot be easily distinguished from the feedback control, making it difficult to formulate a clear business case for the use of preview control. Therefore, the aim of this work is to formulate a modular MPC layer on top of a given output feedback blade-pitch controller, with a view to retaining the closed-loop robustness and frequency-domain performance of the latter. We derive a key result that proves that the proposed modular MPC layer handles real-time advance measurements and impacts the existing closed-loop system if and only if constraints are violated. The separate nature of the proposed controller structure enables clear and transparent quantification of the benefits gained by using preview control, beyond that of the underlying feedback controller. This is illustrated by results obtained from high-fidelity closed-loop turbine simulations, showing the performance comparison between a nominal feedback controller and an additional MPC-based preview controller. The proposed control scheme incorporating knowledge of the oncoming wind and constraints achieved significant 43% and 30% reductions in the rotor speed and flap-wise blade moment standard deviations, respectively. Additionally, the chance of constraint violations on the rotor speed decreased remarkably from 2.15% to 0.01%, compared to the nominal controller.

Adaptive fault accommodation of pitch actuator stuck type of fault in floating offshore wind turbines: a subspace predictive repetitive control approach

“…However, when the system parameters vary with time, no guarantee can be made for the stability and robustness of the adaptive repetitive control law. Some approaches have been developed to increase the robustness and stability of the model-based control strategy, such as cautious  2 optimal control design 43 , preview predictive control layer design 44 . However, it is still an open question for the data-driven FTIPC and will be further investigated in the future.…”

A Spatiotemporal Estimation Framework for Real-World LIDAR Wind Speed Measurements

“…An average MRMSE of 12.6% was achieved for the estimation of real-world wind data with LIDAR preview distances ranging from 50 to 185 m. For application to the preview control of wind turbines, the recommended preview distance is determined by the blade-pitch system bandwidth [10]. The proposed estimator is yet to be investigated for its benefits in the preview control of wind turbines by implementing the estimator for the modular model predictive control (MPC) layer proposed in [38], which had assumed perfect wind preview knowledge.…”

Estimation and Control of Wind Turbine Tower Vibrations Based on Individual Blade-Pitch Strategies

“…Secondly, consider the existing Coleman transform-based IPC controller K ipc ∈ R 2×2 , adopted from [11], [19]:…”