Robust Control Design for Load Reduction on a Liberty Wind Turbine

2016 ◽  
Author(s):  
Daniel Ossmann ◽  
Julian Theis ◽  
Peter Seiler
Keyword(s):  
Wind Turbine ◽  
Control Strategies ◽  
Control Design ◽  
Load Reduction ◽  
University Of Minnesota ◽  
Control Loops ◽  
Pitch Control ◽  
Robust Control Design ◽  
And Performance ◽  
Utility Scale

The increasing size of modern wind turbines also increases the structural loads on the turbine caused by effects like turbulence or asymmetries in the inflowing wind field. Consequently, the use of advanced control algorithms for active load reduction has become a relevant part of current wind turbine control systems. In this paper, an H∞-norm optimal multivariable control design approach for an individual blade-pitch control law is presented. It reduces the structural loads both on the rotating and non-rotating parts of the turbine. Classical individual blade-pitch control strategies rely on single control loops with low bandwidth. The proposed approach makes it possible to use a higher bandwidth since it takes into account coupling at higher frequencies. A controller is designed for the utility-scale 2.5 MW Liberty research turbine operated by the University of Minnesota. Stability and performance are verified using a high-fidelity nonlinear benchmark model.

Field testing of multi-variable individual pitch control on a utility-scale wind turbine

2021 ◽  
Vol 170 ◽  
pp. 1245-1256
Author(s):  
Daniel Ossmann ◽  
Peter Seiler ◽  
Christopher Milliren ◽  
Alan Danker
Keyword(s):  
Wind Turbine ◽  
Field Testing ◽  
Pitch Control ◽  
Utility Scale ◽  
Individual Pitch Control

Application of Combined Feedforward and Feedback Controller With Shaped Input to Benchmark Problem

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Young Joo Shin ◽  
Peter H. Meckl
Keyword(s):  
Feedback Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Control Design ◽  
Single Frequency ◽  
Benchmark Problems ◽  
Control Force ◽  
Benchmark Problem ◽  
Advantages And Disadvantages ◽  
Robust Control Design

Benchmark problems have been used to evaluate the performance of a variety of robust control design methodologies by many control engineers over the past 2 decades. A benchmark is a simple but meaningful problem to highlight the advantages and disadvantages of different control strategies. This paper verifies the performance of a new control strategy, which is called combined feedforward and feedback control with shaped input (CFFS), through a benchmark problem applied to a two-mass-spring system. CFFS, which consists of feedback and feedforward controllers and shaped input, can achieve high performance with a simple controller design. This control strategy has several unique characteristics. First, the shaped input is designed to extract energy from the flexible modes, which means that a simpler feedback control design based on a rigid-body model can be used. In addition, only a single frequency must be attenuated to reduce residual vibration of both masses. Second, only the dynamics between control force and the first mass need to be considered in designing both feedback and feedforward controllers. The proposed control strategy is applied to a benchmark problem and its performance is compared with that obtained using two alternative control strategies.

Individual Pitch Control for Wind Turbine Load Reduction Enhanced With Inter-Turbine Wake Modelling

2011 ◽  
Author(s):  
Zhongzhou Yang ◽  
Yaoyu Li ◽  
John E. Seem
Keyword(s):  
Wind Turbine ◽  
State Space ◽  
Wind Profile ◽  
State Space Models ◽  
Load Reduction ◽  
Pitch Control ◽  
Wake Interaction ◽  
Wake Model ◽  
Individual Pitch Control ◽  
Turbine Wake

Individual pitch control (IPC) for wind turbine load reduction in Region 3 operation is improved when wake interaction is considered. The Larsen wake model is applied for composing the rotor wind profile for downstream turbines under wake interaction. The wind profile of the turbine wake was generated by modifying the NREL’s TurbSim codes. The state-space models of wind turbine were obtained via linearization of wind turbine model available in the NREL’s aeroelastic design code FAST. In particular, in order to obtain more accurate state-space models, equivalent circular wind profile was generated so as to better determine the local pitch reference. Based on such models, IPC controllers were designed following the disturbance accommodating control (DAC) and periodic control framework. The simulation results showed that the turbine loads can be further reduced using the switching control scheme based on wake modeling, as compared with the generic DAC without wake consideration.

Robust control design of variable speed wind turbine using quantitative feedback theory

2018 ◽  
Vol 232 (6) ◽  
pp. 691-705 ◽  
Author(s):  
Navdeep Singh ◽  
Bhanu Pratap ◽  
Akhilesh Swarup
Keyword(s):  
Robust Control ◽  
Wind Turbine ◽  
Control Design ◽  
Control Technique ◽  
Effective Control ◽  
Quantitative Feedback Theory ◽  
Variable Speed ◽  
Variable Speed Wind Turbine ◽  
Wide Range ◽  
Robust Control Design

A robust control design of a three blade, horizontal axis variable speed wind turbine is developed in this paper. The variable speed wind turbine model consists of higher order nonlinear dynamics where uncertainty has been considered in the plant parameters. Quantitative feedback theory is an effective and efficient, robust control technique through which the desired specifications over a specified range of parametric uncertainty can easily be achieved in the frequency domain. The proposed robust torque and pitch control in variable speed wind turbine using quantitative feedback theory satisfy prescribed gain and phase margin, degree of tracking for the robust performance, fast convergence, noise attenuation, and input and output disturbance rejection. The advantages of the proposed robust control design are the consideration of a wide range of performance specifications and achieving effective control over an increased operating frequency range. The simulation results demonstrate the satisfactory performance of proposed quantitative feedback theory-based controller and prefilter which fulfill the necessary conditions such as robust stability and robust tracking. Further, it has been shown that the performance of the quantitative feedback theory-based controller is better than the performance with a standard wind turbine controller and also from the performance by proportional-integral controller.

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