Towards Active Flow Control on a Research Scale Wind Turbine Using PID controlled Trailing Edge Flaps

Bartholomay, Sirko; Michos, Grigoris; Perez‐Becker, Sebastian; Pechlivanoglou, George; Nayeri, Christian Navid; Nikolaouk, Grigoris; Paschereit, Christian Oliver

doi:10.2514/6.2018-1245

Cited by 14 publications

(16 citation statements)

References 11 publications

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“…However, the AoA from the three-hole-probe method captures a drop near the zone of azimuth angles φ ≈ 90 • and φ ≈ 290 • . This behavior has been seen in previous results of Klein et al (2018), Bartholomay et al (2018) and Marten et al (2018).…”

Section: Pressure Distributionsupporting

confidence: 89%

“…Ronsten (1992) showed a good agreement between the pressure distribution over nonrotating and rotating blades along span positions of r/R ≥ 0.55 and r/R ≥ 0.3 at tip speed ratios of 4.32 and 7.37, respectively. Guntur and Sørensen (2012) presented different methods to determine the AoA for the MEXICO rotor (Bechmann et al, 2011) based on CFD data. One of the approaches is based on matching up C P distributions from 2-D and 3-D data, where the AoA was known in the former case.…”

Section: Contributormentioning

confidence: 99%

“…The operation range of the five-hole probe was studied by Moscardi and Johnson (2016) for a large range of pitch and yaw angles (±50 • ), using the test rig with only one blade. Bartholomay et al (2018) showed AoA estimation through three-hole probes, from the Berlin Research Turbine (BeRT). The three-hole-probe calibration was made under axial inflow and performed on-blade operation for axial and yawed inflows up to 30 • .…”

Section: Introductionmentioning

confidence: 99%

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Determination of the angle of attack on a research wind turbine rotor blade using surface pressure measurements

et al. 2020

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Abstract. In this paper, a method to determine the angle of attack on a wind turbine rotor blade using a chordwise pressure distribution measurement was applied. The approach used a reduced number of pressure tap data located close to the blade leading edge. The results were compared with the measurements from three external probes mounted on the blade at different radial positions and with analytical calculations. Both experimental approaches used in this study are based on the 2-D flow assumption; the pressure tap method is an application of the thin airfoil theory, while the probe method applies geometrical and induction corrections to the measurement data. The experiments were conducted in the wind tunnel at the Hermann Föttinger Institut of the Technische Universität Berlin. The research turbine is a three-bladed upwind horizontal axis wind turbine model with a rotor diameter of 3 m. The measurements were carried out at rated conditions with a tip speed ratio of 4.35, and different yaw and pitch angles were tested in order to compare the approaches over a wide range of conditions. Results show that the pressure tap method is suitable and provides a similar angle of attack to the external probe measurements as well as the analytical calculations. This is a significant step for the experimental determination of the local angle of attack, as it eliminates the need for external probes, which affect the flow over the blade and require additional calibration.

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Section: Pressure Distributionsupporting

confidence: 89%

Section: Contributormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of the angle of attack on a research wind turbine rotor blade using surface pressure measurements

et al. 2020

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“…Lately, Bartholomay et al (2017) developed an experimental method to generate a locally constant inflow disturbance that the turbine is exposed to. Furthermore, Bartholomay et al (2018) employed yaw situations as test cases for potential load alleviation. These two inflow disturbances create 1p variations in flapwise bending moment at a reduced frequency of k = π • c/U rel = 0.09, whereas c is the chord und U rel is the relative velocity in reference to the 75% spanwise position.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, the wing was equipped with a custommade three-hole probe (Fig. 3) that was previously used on the model wind turbine BeRT (Klein et al (2017); Bartholomay et al (2018)). The two outer tubes have a 45 • chamfer angle, whereas as the inner tube has a chamfer angle of 0 • .…”

Section: Measurement Hardwarementioning

confidence: 99%

Pressure Based Lift Estimation and its Application to Feedforward Load Control employing Trailing Edge Flaps

Bartholomay¹,

Wester²,

Perez‐Becker³

et al. 2020

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Abstract. This experimental load control study presents results of an active trailing edge flap feedforward controller for wind turbine applications. The controller input is derived from pressure based lift estimation methods that rely either on a quasi-steady method, based on a three-hole probe, or on an unsteady method that is based on three selected surface pressure ports. Furthermore, a standard feedback controller, based on force balance measurements, is compared to the feedforward control. A Clark-Y airfoil is employed for the wing that is equipped with a trailing edge flap of x/c = 30 % chordwise extension. Inflow disturbances are created by a two-dimensional active grid. The Reynolds number is Re = 290,000 and reduced frequencies of k = 0.07 up to k = 0.32 are analyzed. Within the first part of the paper, the lift estimation methods are compared. The surface pressure based method shows generally more accurate results whereas the three-hole probe estimate overpredicts the lift amplitudes with increasing frequencies. Nonetheless, employing the latter as input to the feedforward controller is more promising as a beneficial phase lead is introduced by this method. A successful load alleviation was achieved up to reduced frequencies of k = 0.192.

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Repetitive model predictive control for load alleviation on a research wind turbine using trailing edge flaps

et al. 2022

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This paper presents the results of an advanced control strategy that employs active trailing edge flaps to reduce the fatigue loads of an experimental wind turbine. The strategy, called repetitive model predictive control, is a multiple-input multipleoutput controller that aims at the alleviation of out-of-plane blade root bending moments. The strategy incorporates the control commands, output errors, and state deviation from the previous rotation. This way, the time lag in the strain sensor input due to the blade inertia is compensated. Additionally, a strategy to limit the computational costs is presented. The load alleviation performance is evaluated at different yaw cases and compared with different individual flap control strategies. The repetitive model predictive control is able to reduce the fatigue loads by up to 23% compared with the better performing individual flap control strategy. This improvement in load reduction is accompanied by an increase in flap travel of up to 7% compared with the individual flap control strategies. K E Y W O R D S fatigue load control, individual flap control, repetitive control, trailing edge flaps | INTRODUCTIONWind energy has become one of the most important sources of renewable energy. In order for this trend to continue, the cost of energy of this technology needs to be as low as possible. A crucial factor for the cost of energy is the employed material for building a turbine. Lowering material input can be achieved by reducing the loads acting on the turbine components. These in turn can be decreased by a load control strategy specifically designed for this purpose. As an example, cyclic and individual pitch control has been studied by various institutes. [1][2][3][4] Substantial research was also carried out into smart rotor control which could supplement pitching of the rotor blades. In particular, employing locally distributed active flow control devices on the blades has drawn a lot of attention in the community. Due to their high bandwidth and control authority, trailing edge flaps are one of the most promising active flow control options. 5 In particular, it was shown that trailing edge flaps achieve the same load reduction for fatigue loads as individual pitch control. 3 A critical aspect of active load control is the choice of sensors for the control strategy. 6 Mostly, active flow control aims at the alleviation of the out-of-plane turbine loads. Therefore, employing a feedback control on the out-of-plane blade root bending moment is a common choice.

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Towards Active Flow Control on a Research Scale Wind Turbine Using PID controlled Trailing Edge Flaps

Cited by 14 publications

References 11 publications

Determination of the angle of attack on a research wind turbine rotor blade using surface pressure measurements

Determination of the angle of attack on a research wind turbine rotor blade using surface pressure measurements

Pressure Based Lift Estimation and its Application to Feedforward Load Control employing Trailing Edge Flaps

Repetitive model predictive control for load alleviation on a research wind turbine using trailing edge flaps

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