No abstract

Floating offshore wind turbines are complex dynamical systems. The use of numerical models is an essential tool for the prediction of the fatigue life, ultimate loads and controller design. The simultaneous wind and wave loading on a non-stationary foundation with a flexible tower makes the development of numerical models difficult, the validation of these numerical models is a challenging task as the floating offshore wind turbine system is expensive and the testing of these may cause loss of the system. The validation of these numerical models is often made on scaled models of the floating offshore wind turbines, which are tested in scaled environmental conditions. In this study, an experimental validation of two numerical models for a floating offshore wind turbines will be conducted. The scaled model is a 1:35 Froude scaled 5 MW offshore wind turbine mounted on a tension-leg platform. The two numerical models are aero-hydro-servo-elastic models. The numerical models are a theoretical model developed in a MATLAB/Simulink environment by the authors, while the other model is developed in the turbine simulation tool FAST. A comparison between the numerical models and the experimental dynamics shows good agreement. Though some effects such as the periodic loading from rotor show a complexity, which is difficult to capture.

No abstract

This paper deals with the design and implementation of an algorithm for non-data aided carrier offset compensation in a QPSK communication system. The work concentrates on frequency synchronization and we propose a new modulation removal algorithm where the carrier offset is corrected in two steps, reducing the computational complexity. Moreover, a FPGAaccelerated implementation is introduced. Initial tests show that the implemented algorithm works as expected and that the Simulink simulation time is reduced by half when accelerated by the FPGA.

Abstract-The increasing market of mobile phones, has increased the need for electricity to power mobile phones, as well. This paper investigates the possibilities to charge a mobile phone by harvesting energy from the surroundings. Some technologies are better suited for this purpose than others. Through previous analyses solar cells and electromagnetic generator were found to be the most suitable solution. This paper will give a basic description of the operating conditions of solar cells and an electromagnetic generator. There will also be a short view on the electrical circuit needed for implementing the harvested energy. Calculations regarding the power produced by amorphous silicon solar cells in both sun light and light from different light emitting sources will be examined. Furthermore calculations of the spring for the electromagnetic generator and the power produced by this device will be examined. Through experiments and data processing the energy delivered by the solar cells and the electromagnetic generator is investigated, furthermore an experiment regarding the movement of the phone will be executed.