Basic Study on Regenerative Air Brake Using Observer-based Thrust Control for Electric Airplane

Yokota, Kentaro; Fujimoto, Hiroshi; Hori, Yoichi

doi:10.1109/amc44022.2020.9244329

Cited by 4 publications

(1 citation statement)

References 6 publications

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“…Though regeneration (as it is referred to when using a propeller) is currently being used in private and small commercial ships, little is published on the design or operation of the propeller (Enge et al, 2013;Gunnarsson et al, 2016). Some research has been conducted on the application of regeneration to electric aircraft, however, the data presented is not directly applicable to the UFOWT application since it is for small propellers used in air (Yokota et al, 2020;Scholtens, 2021).…”

Section: Propeller Power Take-off (Regeneration)mentioning

confidence: 99%

Comparison of optimal power production and operation of unmoored floating offshore wind turbines and energy ships

Connolly

Crawford

2022

Preprint

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Abstract. As the need to transition from global reliance on fossil fuels grows, solutions for producing green alternative fuels are necessary. These fuels will be especially important for hard-to-decarbonize sectors such as shipping. Mobile offshore wind energy systems (MOWESs) have been proposed as one such solution. These systems aim to harness the far-offshore wind resource, which is abundant and yet untapped because of installation and grid-connection limitations. Two classes of MOWES have been proposed in the literature: unmoored floating offshore wind turbines (UFOWTs) and energy ships (ESs). Both systems operate as autonomous Power to X (PtX) plants, powered entirely by wind energy, and so can be used to produce synthetic green fuels such as hydrogen or ammonia, or for other energy intensive applications such as direct air carbon capture. The two technologies differ in form; UFOWTs are based on a conventional FOWT but include propellers in place of mooring lines for sea-/course-keeping, while ESs operate like a sailing ship and generate power via hydroturbines mounted on the underside of the hull. Though much research and development is necessary for these systems to be feasible, the promise of harnessing strong winds far offshore, as well as the potential to avoid siting regulatory challenges, are enticing. This paper develops models of each MOWES concept to compare their power production on a consistent basis. The performance of the technologies are examined at steady-state operating points across relative wind speeds and angles. An optimization scheme is used to determine the values of the control variables which define the operating point for each set of environmental conditions. Results for each model show good agreement with published results for both UFOWTs and ESs. Model results suggest that UFOWTs can generate more power than ESs under ideal environmental conditions, but are very sensitive to off-design operating conditions. In above-rated wind speeds, the UFOWT is able to produce as much power as a conventional, moored FOWT, whereas the ES cannot, since some power is always consumed to spin the Flettner rotors. The models developed here and their results may both be useful in future works that focus on the routing of UFOWTs, or holistically designing a mobile UFOWT. Although differences in the performance of the systems have been identified, more work is necessary to discern which is a more viable producer of green e-fuels.

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Section: Propeller Power Take-off (Regeneration)mentioning

confidence: 99%

Comparison of optimal power production and operation of unmoored floating offshore wind turbines and energy ships

Connolly

Crawford

2022

Preprint

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Observer-based Angle of Attack Estimation for Tilt-Wing eVTOL Aircraft

Yokota

Fujimoto

Kobayashi

2021

2021 IEEE International Conference on Mechatronics (ICM)

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Pitch Angle Control by Regenerative Air Brake for Electric Aircraft

Yokota

Fujimoto

2022

IEEJ Journal IA

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Conventional aircraft use mechanical air brakes to adjust their descent paths; however, the lift-drag ratio cannot be continuously controlled, which results in zigzag descent paths. Previous research has shown that the negative thrust produced by the windmilling propeller works as a substitute air brake called the regenerative air brake. This paper proposes a new pitch angle control method using the regenerative air brake. The proposed method includes thrust estimation, negative thrust control, airspeed estimation, and pitch angle control using the pitching-jerk-based disturbance observer. The effectiveness of the proposed method is verified via simulations and experiments in a wind tunnel.

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Basic Study on Regenerative Air Brake Using Observer-based Thrust Control for Electric Airplane

Cited by 4 publications

References 6 publications

Comparison of optimal power production and operation of unmoored floating offshore wind turbines and energy ships

Comparison of optimal power production and operation of unmoored floating offshore wind turbines and energy ships

Observer-based Angle of Attack Estimation for Tilt-Wing eVTOL Aircraft

Pitch Angle Control by Regenerative Air Brake for Electric Aircraft

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