Individual pitch control of wind turbines using local inflow measurements

Thomsen, Sven Creutz; Niemann, Hans Henrik; Poulsen, Niels Kjølstad

doi:10.3182/20080706-5-kr-1001.00942

Cited by 20 publications

(13 citation statements)

References 10 publications

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“…The preceding analysis assumed a measurement of the aerodynamic lift force on a blade section. To our knowledge, no previous study on the use of local inflow measurements has used this specific signal as the basis for subsequent control, tending to use angle‐of‐attack and/or relative velocity information instead (eg, Larsen et al and Thomsen et al). To see how the lift force can be determined in practice consider a pitot‐static tube mounted on the leading edge of an airfoil section (Figure ) that provides direct measurements of the inflow angle of attack

α false(t false) \in double-struckR

and relative wind speed

v_{rel} false(t false) \in double-struckR

.…”

Section: Cascaded Ipc and Blade Inflow Measurementmentioning

confidence: 99%

Overcoming fundamental limitations of wind turbine individual blade pitch control with inflow sensors

2018

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Individual pitch control (IPC) provides an important means of attenuating harmful fatigue and extreme loads upon the load bearing structures of a wind turbine. Conventional IPC architectures determine the additional pitch demand signals required for load mitigation in response to measurements of the flap‐wise blade‐root bending moments. However, the performance of such architectures is fundamentally limited by bandwidth constraints imposed by the blade dynamics. Seeking to overcome this problem, we present a simple solution based upon a local blade inflow measurement on each blade. Importantly, this extra measurement enables the implementation of an additional cascaded feedback controller that overcomes the existing IPC performance limitation and hence yields significantly improved load reductions. Numerical demonstration upon a high‐fidelity and nonlinear wind turbine model reveals (1) 60% reduction in the amplitude of the dominant 1P fatigue loads and (2) 59% reduction in the amplitude of extreme wind shear‐induced blade loads, compared with a conventional IPC controller with the same robust stability margin. This paper therefore represents a significant alternative to wind turbine IPC load mitigation as compared with light detection and ranging‐based feedforward control approaches.

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α false(t false) \in double-struckR

and relative wind speed

v_{rel} false(t false) \in double-struckR

.…”

Section: Cascaded Ipc and Blade Inflow Measurementmentioning

confidence: 99%

Overcoming fundamental limitations of wind turbine individual blade pitch control with inflow sensors

2018

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“…In this case, separate actuators and controllers may be necessary, opening up even more control opportunities [14,46,47].…”

Section: Advanced Control Of Wind Turbinesmentioning

confidence: 99%

Overview of Modelling and Advanced Control Strategies for Wind Turbine Systems

Simani

2015

Energies

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Abstract:The motivation for this paper comes from a real need to have an overview of the challenges of modelling and control for very demanding systems, such as wind turbine systems, which require reliability, availability, maintainability, and safety over power conversion efficiency. These issues have begun to stimulate research and development in the wide control community particularly for these installations that need a high degree of "sustainability". Note that this represents a key point for offshore wind turbines, since they are characterised by expensive and/or safety critical maintenance work. In this case, a clear conflict exists between ensuring a high degree of availability and reducing maintenance times, which affect the final energy cost. On the other hand, wind turbines have highly nonlinear dynamics, with a stochastic and uncontrollable driving force as input in the form of wind speed, thus representing an interesting challenge also from the modelling point of view. Suitable control methods can provide a sustainable optimisation of the energy conversion efficiency over wider than normally expected working conditions. Moreover, a proper mathematical description of the wind turbine system should be able to capture the complete behaviour of the process under monitoring, thus providing an important impact on the control design itself. In this way, the control scheme could guarantee prescribed performance, whilst also giving a degree of "tolerance" to possible deviation of characteristic properties or system parameters from standard conditions, if properly included in the wind turbine model itself. The most important developments in advanced controllers for wind turbines are also briefly referenced, and open problems in the areas of modelling of wind turbines are finally outlined.

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“…One major drawback of collective pitch control is its incapability to compensate for the asymmetric loads caused by the wind field. Another approach [24,25] for the blade pitch control was to adjust the blade pitch individually and thereby attenuating the effects of asymmetric wind loads. This paper investigates in detail the airloads and performance of the wind turbine in the vertical wind shear.…”

Section: Introductionmentioning

confidence: 99%