| Popis: |
Over the last 30 years a number of airborne module-based wind energy concepts have been proposed within the last decade in order to offer a possibility of harnessing the energy of high-altitude/high-speed, and, thus, to provide a viable alternative to ground-based wind-turbine systems which have steadily reached their performance peak due to blade and generator size constraints, high investment costs, and relatively unpredictable nature of near-surface winds. Within the typical high-altitude wind energy (HAWE) system, the airborne module is tethered via a cable (rope) to the motor/generator unit located at the ground level, which results in intermittent nature of airborne wind energy system’s power production, and mandates utilization of sufficiently large energy storage in order to provide constant power supply to the electrical power grid. This paper focuses on the design of a suitable control strategy for a HAWE system ground station power-plant equipped with an ultracapacitor energy storage system, aimed at coordinating the individual power sources connected to the common DC link, and comprising: (i) generator speed control system and airborne module coordination via cable tension, (ii) DC link power flow coordination control, and (iii) grid inverter control aimed at smooth power delivery to the utility electrical grid. The effectiveness of the proposed ground station control system is verified by means of comprehensive computer simulations for characteristic HAWE system operating scenarios, with preliminary results pointing out towards robust and effective power flow control within the HAWE ground station and steady (uninterrupted) power delivery to the grid. |
