Special Issue "Airborne Wind Energy Systems"

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "B2: Wind, Wave and Tidal Energy".

Deadline for manuscript submissions: 1 November 2022.

Special Issue Editors

Prof. Dr. Christoph M. Hackl
E-Mail Website1 Website2
Guest Editor
Department of Electrical Engineering and Information Technology, Munich University of Applied Sciences (MUAS), 80335 Munich, Germany
Interests: modeling; control; efficiency enhancements; fault detection and condition monitoring of mechatronic and renewable energy systems
Special Issues, Collections and Topics in MDPI journals
Dr. Roland Schmehl
E-Mail Website
Guest Editor
Faculty of Aerospace Engineering, Delft University of Technology (TU Delft), 2629 HS Delft, The Netherlands
Interests: airborne wind energy; fluid–structure interaction; two-phase flows; liquid droplet; modeling; renewable energy technologies; numerical analysis; power generation; engineering thermodynamics; computational fluid dynamics; fluid mechanics; numerical simulation; thermal engineering; numerical modeling; aerodynamics

Special Issue Information

Dear colleagues,

Airborne wind energy (AWE) systems convert wind energy into electrical energy using autonomous tethered flying devices. Deemed a potentially game-changing solution to clean and sustainable energy generation, AWE is increasingly attracting the attention of governments, policymakers and industry worldwide. AWE technology can significantly reduce the levelized cost of energy (LCoE) by eliminating (i) the drive-train installation, (ii) a large part of the rotor blades, (iii) the tower, and (iv) the foundation, which make up for about 50% of the conventional turbine costs. On the other hand, the development of this technology is also facing substantial technical challenges. Important aspects are, for example, autonomous, efficient, reliable, safe, and uninterrupted operation of AWE systems and their interconnection with the future power grid.

We cordially invite original manuscripts presenting recent advances in this important and interdisciplinary research field with particular focus on but not limited to the following:

  1. Aerodynamics, aeroelasticity, and structural dynamics;
  2. Flight dynamic modeling;
  3. Flightpath planning and control of AWE systems;
  4. AWE design optimization;
  5. Higher altitude wind resources;
  6. Experimental testing of prototypes;
  7. Efficiency enhancements (by, e.g., intelligent design and/or control);
  8. Nonlinear, optimal, and fault-tolerant control strategies;
  9. Fault detection methods and condition monitoring approaches;
  10. Robust, fault-tolerant and flexible grid connection/integration (e.g., grid-supporting, -feeding, -forming including black start capability);
  11. Economic and market analysis;
  12. AWE policy-making, environmental impact, and societal acceptance.

The Special Issue will present cutting-edge research results connected to AWE technology as a basis for enduring operation. All research results must be presented in a mathematically thorough (e.g., in state space) but understandable manner to encourage insights and re-implementation by the readers so that the knowledge basis is shared, spread, and extended to promote AWE systems to the market. All results should be validated by simulation and measurement results (if possible).

Prof. Dr. Christoph M. Hackl
Dr. Roland Schmehl
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • airborne wind energy system
  • aerodynamics
  • aeroelasticity
  • dynamic modeling
  • performance modeling
  • fault-tolerance
  • reliable operation
  • safety engineering
  • flexible grid connection

Published Papers (3 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Article
Cascade Control of the Ground Station Module of an Airborne Wind Energy System
Energies 2021, 14(24), 8337; https://doi.org/10.3390/en14248337 - 10 Dec 2021
Viewed by 509
Abstract
An airborne wind energy system (AWES) can harvest stronger wind streams at higher altitudes which are not accessible to conventional wind turbines. The operation of AWES requires a controller for the tethered aircraft/kite module (KM), as well as a controller for the ground [...] Read more.
An airborne wind energy system (AWES) can harvest stronger wind streams at higher altitudes which are not accessible to conventional wind turbines. The operation of AWES requires a controller for the tethered aircraft/kite module (KM), as well as a controller for the ground station module (GSM). The literature regarding the control of AWES mostly focuses on the trajectory tracking of the KM. However, an advanced control of the GSM is also key to the successful operation of an AWES. In this paper we propose a cascaded control strategy for the GSM of an AWES during the traction or power generation phase. The GSM comprises a winch and a three-phase induction machine (IM), which acts as a generator. In the outer control-loop, an integral sliding mode control (SMC) algorithm is designed to keep the winch velocity at the prescribed level. A detailed stability analysis is also presented for the existence of the SMC for the perturbed winch system. The rotor flux-based field oriented control (RFOC) of the IM constitutes the inner control-loop. Due to the sophisticated RFOC, the decoupled and instantaneous control of torque and rotor flux is made possible using decentralized proportional integral (PI) controllers. The unknown states required to design RFOC are estimated using a discrete time Kalman filter (DKF), which is based on the quasi-linear model of the IM. The designed GSM controller is integrated with an already developed KM, and the AWES is simulated using MATLAB and Simulink. The simulation study shows that the GSM control system exhibits appropriate performance even in the presence of the wind gusts, which account for the external disturbance. Full article
(This article belongs to the Special Issue Airborne Wind Energy Systems)
Show Figures

Graphical abstract

Article
Three-Dimensional Unsteady Aerodynamic Analysis of a Rigid-Framed Delta Kite Applied to Airborne Wind Energy
Energies 2021, 14(23), 8080; https://doi.org/10.3390/en14238080 - 02 Dec 2021
Viewed by 580
Abstract
The validity of using a low-computational-cost model for the aerodynamic characterization of Airborne Wind Energy Systems was studied by benchmarking a three-dimensional Unsteady Panel Method (UnPaM) with experimental data from a flight test campaign of a two-line Rigid-Framed Delta kite. The latter, and [...] Read more.
The validity of using a low-computational-cost model for the aerodynamic characterization of Airborne Wind Energy Systems was studied by benchmarking a three-dimensional Unsteady Panel Method (UnPaM) with experimental data from a flight test campaign of a two-line Rigid-Framed Delta kite. The latter, and a subsequent analysis of the experimental data, provided the evolution of the tether tensions, the full kinematic state of the kite (aerodynamic velocity and angular velocity vectors, among others), and its aerodynamic coefficients. The history of the kinematic state was used as input for UnPaM that provided a set of theoretical aerodynamic coefficients. Disparate conclusions were found when comparing the experimental and theoretical aerodynamic coefficients. For a wide range of angles of attack and sideslip angles, the agreement in the lift and lateral force coefficients was good and moderate, respectively, considering UnPaM is a potential flow tool. As expected, UnPaM predicts a much lower drag because it ignores viscous effects. The comparison of the aerodynamic torque coefficients is more delicate due to uncertainties on the experimental data. Besides fully non-stationary simulations, the lift coefficient was also studied with UnPaM by assuming quasi-steady and steady conditions. It was found that for a typical figure-of-eight trajectory there are no significant differences between unsteady and quasi-steady approaches allowing for fast simulations. Full article
(This article belongs to the Special Issue Airborne Wind Energy Systems)
Show Figures

Figure 1

Article
Flight Stability of Rigid Wing Airborne Wind Energy Systems
Energies 2021, 14(22), 7704; https://doi.org/10.3390/en14227704 - 17 Nov 2021
Viewed by 512
Abstract
The flight mechanics of rigid wing Airborne Wind Energy Systems (AWESs) is fundamentally different from the one of conventional aircrafts. The presence of the tether largely impacts the system dynamics, making the flying craft to experience forces which can be an order of [...] Read more.
The flight mechanics of rigid wing Airborne Wind Energy Systems (AWESs) is fundamentally different from the one of conventional aircrafts. The presence of the tether largely impacts the system dynamics, making the flying craft to experience forces which can be an order of magnitude larger than those experienced by conventional aircrafts. Moreover, an AWES needs to deal with a sustained yet unpredictable wind, and the ensuing requirements for flight maneuvers in order to achieve prescribed control and power production goals. A way to maximize energy capture while facing disturbances without requiring an excessive contribution from active control is that of suitably designing the AWES craft to feature good flight dynamics characteristics. In this study, a baseline circular flight path is considered, and a steady state condition is defined by modeling all fluctuating dynamic terms over the flight loop as disturbances. In-flight stability is studied by linearizing the equations of motion on this baseline trajectory. In populating a linearized dynamic model, analytical derivatives of external forces are computed by applying well-known aerodynamic theories, allowing for a fast formulation of the linearized problem and for a quantitative understanding of how design parameters influence stability. A complete eigenanalysis of an example tethered system is carried out, showing that a stable-by-design AWES can be obtained and how. With the help of the example, it is shown how conventional aircraft eigenmodes are modified for an AWES and new eigenmodes, typical of AWESs, are introduced and explained. The modeling approach presented in the paper sets the basis for a holistic design of AWES that will follow this work. Full article
(This article belongs to the Special Issue Airborne Wind Energy Systems)
Show Figures

Figure 1

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: An analytical wake model for crosswind kite power systems
Authors: Mojtaba Kheiri; Mher M. Karakouzian; Frederic Bourgault
Affiliation: Mojtaba Kheiri (Concordia University, Montreal, QC, Canada) Mher M. Karakouzian (Queen's University, Kingston, ON, Canada) Frederic Bourgault (New Leaf Management, Vancouver, BC, Canada)
Abstract: This paper presents an analytical model for calculating the average flow velocity and radii of the annular wake developed downstream of a crosswind kite power system. The model is formulated based on the widely used Jensen's model (Technical Report Riso-M; No. 2411, 1983), which was developed for conventional wind turbines, and thus has a simple form. Expressions for the dimensionless wake flow velocity and wake radii are obtained by assuming self-similarity of flow velocity and linear wake expansion. Comparisons are made between numerical results from the proposed model and those from high-fidelity CFD simulations. The level of agreement was found to be reasonably good. Such analytical models are indispensable for kite farm layout design and optimization, where aerodynamic interactions between kite systems should be considered.

Back to TopTop