Airborne wind energy systems (AWESs) offer a promising route to high-altitude wind harvesting, but their commercialization remains limited by the challenge of converting highly dynamic tethered flight power into stable electrical energy. While most research has focused on flight trajectories and control, the mechanical-to-electrical conversion stage requires further experimental validation. This paper introduces a validated electrical test bench emulator and a torque-ripple-optimized model predictive control (MPC) strategy, evaluated using two real AWES flight datasets. The emulator reproduces variable tether forces and reeling dynamics under optimal figure-eight crosswind flight. Two DC-bus topologies are compared: a separated bus that accurately mimics AWES storage dynamics (≈ 98 % fidelity) but demands 45 %–55 % more battery capacity and a common bus that recirculates energy, reducing storage needs by two-thirds. When realistic storage dynamic emulation is required, the separated-bus configuration is the only suitable option. The proposed MPC ensures precise generator speed and torque regulation, achieving torque-tracking root mean squared errors (RMSEs) below 0.11 % (Dataset 1) and 0.14 % (Dataset 2) and speed-tracking RMSEs of 0.44 % and 0.82 %, respectively. Overall energy efficiencies reach 82 % with Dataset 1 and 60 % with Dataset 2, with peak instantaneous efficiencies of 93 % and 88 %. Permanent magnet synchronous generators (PMSGs) outperform induction machines (IMs) by 4 % in Dataset 1 and up to 20 % in Dataset 2, with instantaneous gains of 2 %–10 % at high power. Off-nominal operation degrades cycle efficiency and drives higher battery cycling even in a common-bus setup, highlighting the importance of correct machine dimensioning. However, when storage dynamics are not under study, the common-bus configuration is the most cost-effective option, requiring less hardware and imposing lower peak discharge stresses. These results establish electrical test bench emulators as essential platforms for systematic evaluation and optimization of AWES power conversion, informing both machine design and control strategies for scalable, efficient AWES deployment.

A mechanical control system and the guidance and control modules of a small-scale and autonomous testbed for three-line kites applied to airborne wind energy are presented. It extends the capabilities of a previously developed infrastructure by (i) changing the actuation system to add a third tether to control the kite pitch angle, (ii) adding running-line tensiometers to measure the three tether tensions while allowing tether reel-in and reel-out and onboard load cells to measure the bridle tensions, and (iii) providing a real-time control system to operate the kite autonomously in figure-eight trajectories. A controller based on a hybrid guidance scheme for figure-eight flight paths, which combines attractor points for the straight segments and a continuous heading angle tracking for the turns, was implemented and validated in an experimental campaign. Two flights of the campaign were used to illustrate the performance of the controller and its capability to adjust the lateral amplitude, elevation, and radius of the turns by varying a few parameters of the guidance module. The proposed control scheme was proven effective in achieving satisfactory and repeatable figure-eight paths. The experimental data collected during the autonomous flight were used to investigate the dynamics and control of the kite and the tethers. A correlation between the heading and roll angles of the kite was identified and modeled with a simple analytical law with empirical coefficients. Similarly to previous works on airborne wind energy, a linear relation between the derivative of the course angle and the steering input was found. The analysis of the on-ground tensiometers and the onboard load cells revealed a variable time delay of up to 0.2 s between both measurements. The work shows that the testbed and its instruments are suitable for investigating the effect of tether sagging and for developing and testing controllers for airborne wind energy systems.

A mechanical control system and the guidance and control modules of a small-scale and autonomous testbed for three-line kites applied to airborne wind energy are presented. It extends the capabilities of a previous developed infrastructure by (i) changing the actuation system to add a third tether to control the kite pitch angle, (ii) adding running line tensiometers to measure the three tether tensions while allowing tether reel-in and reel-out, and on-board load cells to measure the bridle tensions, (iii) a real-time control system to operate the kite autonomously in figure-eight trajectories. A controller based on a hybrid guidance scheme for figure-eight flight paths, which combines attractor points for the straight segments and a continuous heading angle tracking for the turns, was implemented and validated in an experimental campaign. Two flights of the campaign were used to illustrate the performance of the controller and its capability to adjust the lateral amplitude, elevation and radius of the turns by varying a few parameters of the guidance module. The proposed control scheme was proven effective in achieving satisfactory and repeatable figure-eight paths. The experimental data collected during the autonomous flight was used to investigate the dynamics and control of the kite and the tethers. A correlation between the heading and roll angles of the kite was identified and modeled with a simple analytical law with empirical coefficients. Similarly to previous works on airborne wind energy, a linear relation between the derivative of the course angle and the steering input was found. The analysis of the on-ground tensiometers and the on-board load cells revealed a variable time delay up to 0.2 s between both measurements. The work shows that the testbed and its instruments are suitable to investigate the effect of tether sagging and to develop and test controllers for airborne wind energy systems.

The residual magnetic dipole moment is one of the primary disturbances in satellites, making its characterization essential for developing effective control strategies. This work presents a low-cost and compact experimental setup consisting of 12 cost-effective magnetic sensors, a non-metallic structure, and a dedicated software with the algorithms to estimate the dipole’s magnitude, direction, and location. In order to study the performance of the setup, three analyses were carried out. Firstly, a simulation framework was prepared to study through Monte Carlo analysis the role of the ambient magnetic field noise, sensors installation errors, and number of sensors. It was found that, under typical laboratory conditions and installation errors, at least eight sensors should be used to obtain reliable estimations. Moreover, the simulation revealed that, in an environment with 150 nT of ambient noise and installation accuracy better than 0.1 mm and 0.1 deg, the errors of the estimated dipole magnitude, direction and location are below 4%, 6 deg, and 7 mm for dipoles above 0.01 Am². Secondly, the performance of the experimental setup was tested by using a dipole generator. In an environment with 450 nT of ambient noise and for moderate fabrication quality, the setup achieved an error smaller than 11% in magnitude, 10 deg in direction, and 15 mm in location for dipoles greater than 0.2 Am². Finally, the setup was used to characterize the dipole parameters of a deorbit device based on electrodynamic tether technology. The results were consistent with an independent characterization performed with a conventional Helmholtz cage-based method.

This article presents an innovative Energy Management System (EMS) for microgrids with Hybrid Energy Storage Systems (HESS), designed to optimize power dispatch, minimize premature degradation of components, and ensure DC bus voltage stability (±2%) under stochastic disturbances. The EMS, implemented in the MATLAB/Simulink Stateflow environment, adopts a multi-objective strategy to regulate the DC bus, manage current limits across the HESS, and compensate for ultra-fast fluctuations (<500 ms) in both generation and demand. Validation combines software-in-the-loop (SiL) simulations with experimental validationon a real prototype subjected to dynamic power cycles. Results demonstrate that the EMS maintains the DC bus voltage within ±1.7% of its nominal value, reallocates loads without exceeding the defined current limits for each storage element, and reduces stress on critical components by 20%. The hierarchical coordination between Li-ion batteries and supercapacitors extends storage system lifetime by prioritizing supercapacitors for fast transients and batteries for sustained power demands. Furthermore, the EMS handles energy surpluses through controlled export or dissipation, preventing overvoltages on the DC bus. Experimental validation confirmed the theoretical model, demonstrating the robustness of the EMS in both isolated and interconnected microgrids, as well as its effectiveness which enables the integration of intermittent renewable sources such as airborne wind energy systems.

A target trajectory generation framework based on Lamé curves (superellipses) applied to airborne wind energy (AWE) systems is presented. The proposed method, which defines the trajectory in the plane spanned by the course angle and the kite azimuth angle, yields closed figure-of-eight paths for the azimuth and elevation angles of the kite. Such a trajectory is tracked by in-house guidance and control algorithms. The former is a look-ahead guidance algorithm that combines heading and course information through a fusion strategy. The latter consists of a proportional controller for the lateral tether-length difference. The performance of the novel target trajectory and the guidance and control solutions was investigated with a high-fidelity AWE simulator that models the kite as a rigid body and includes tether elasticity and flexibility. The simulation campaign showed that the target trajectory is tracked with a root mean square error below one degree. A Monte Carlo analysis varying the initial conditions demonstrated the robustness of the algorithms and Floquet theory was used to prove the stability of the resulting periodic orbits. Finally, compared to classical lemniscate trajectories under a similar mean tether tension, a parametric analysis showed that the proposed Lamé curves can reduce the tether tension deviation by 22.6%.