Narrow Results

Modeling wind speed time series (WSTS) has important implications in wind energy studies. This paper provides a method to modeling WSTS with continuous state markov chain (CSMC). The basic feature of the method is describing WSTS in continuous state space, which can reduce the number of parameters and avoid the loss of information. Case studies are used to illustrate the capabilities of the proposed method. The results prove that the method can offer satisfactory fit for both probability distribution and temporal dependence. The comparison shows that the proposed method outperforms discrete state markov chain in terms of accuracy and simplicity.

This work presents a vector control (VC) of an emerging brushless doubly-fed reluctance (BDFRG) technology for large wind turbine applications. The BDFRG has been receiving increasing attention due to its low operation and maintenance costs afforded by the use of partially-rated power electronics, and the high reliability of brushless assembly, while offering performance competitive to its traditional slip-ring counterpart, the doubly-fed induction generator (DFIG). A robust VC strategy has been developed for a custom-designed BDFRG fed from a conventional ‘back-to-back’ IGBT converter. Preliminary studies have evaluated the algorithm under the power factor control (PFC) conditions which allow the enhanced efficiency of the generator-converter set and the entire wind energy conversion systems (WECS).

The core of the present work focuses on the detailed analysis on the wind power potential of the Ponza Island. The results have been obtained thanks to the use of advanced software tools developed specifically for the purpose of wind data elaboration. The main output of this analysis is a detailed map representing the wind farm locations and an estimation of 4,5 MW of installed wind power equivalent to an annual production of 9 GWh of electric power (that is the 90% of the annual demand of the entire island). Finally the work presents an innovative way of project-financing making the whole project feasible and easy to adopt for the public administration.

Research for sail-assisted technologies should be strengthened for promoting the development of sail assisted project. This paper mainly investigates the sail structure design, dynamic performance and the sail driving control strategy for the large ocean-going sail-assisted ship. For the circular thin optimal sail of one 48000 DWT bulk carrier, the aerodynamic characteristics was analyzed and the sail area was selected through combining with the model parameters from the results of the experimental analysis. Then, the torque for each set of sail was roughly calculated. According to the actual requirements of the sail driving control for energy-saving and driving-safety the hydraulic control is feasible. Compared two traditional hydraulic control systems, the improvement scheme of hydraulic control with variable-frequency technology was further proposed which is a more optimal control method for sail driving control of large ocean-going ships.

In this paper, a pitch angle controller is designed based on adaptive control theory to guarantee steady generator power output while reducing the mechanical loads at above rated wind speed. A non-affine model of the pitch regulated variable-speed wind turbine is built to formulate complicated aerodynamics. The adaptive pitch angle controller assures wind energy conversion system of uniformly bounded transient response in the presence of rapidly changing wind speed, in addition to stable generator angle speed. Without the loss of system robustness, we can improve the performance bounds of adaptive controller by increasing the adaptation rate. Simulation results on GH Bladed software package show that more steady operating output power is obtained by the adaptive controller compared to the traditional pitch angle controller adopted in industry.

This paper deals with nonlinear model based adaptive power capture control of wind energy conversion systems (WECS) using online approximator (OLA) in low-speed region. Compared with the traditional linear techniques valid only around an operating point, which may result in poor system performance and low reliability since the operating point may change with time due to the stochastic operating conditions, the developed controller in this paper is totally a nonlinear one capable of covering the whole operating range. In addition, with the aid of a two-layer neural network, we waive the requirement of system dynamics and aerodynamic torque. Furthermore, the weights of neural network are updated in an online manner, which means that no off-line training is needed. Finally, the effectiveness and merits of our proposed controller are verified on a 1.5 MW three-blade wind turbine using the FAST (Fatigue, Aerodynamics, Structures, and Turbulence) code developed by the National Renewable Energy Laboratory (NREL).

The paper studies automobile styling mode and designing way by the character of new energy-wind energy and solves the problems on how to grasp the characters of newenergy automobile styling and the application of new energy. It analyzes the relationship between wind energy conversion and styling in the automobile styling design through combining air flow principle and practical cases, realizes the practical application of the regenerating wind energy character in automobile headstock and body styling design of the new-energy automobile effectively, and advances the balance between aesthetics and aeromechanics in the automobile styling and its corresponding solutions.

At the latest public reports of the Intergovernmental Panel on Climate Change (IPCC) or the UN Climate Change Conferences, a socio-political discussion arose over possible harmful impacts of fossil energy sources for the global climate and our environment. Also, due to the still unsolved problem of radioactive waste disposal and diverse tragic incidents in nuclear power plants within the last years, many experts criticize the use of nuclear power as a non-sustainable energy source. With regards to the finiteness and environmental harmfulness of fossil energy sources and the danger of nuclear material for present and future generations, the importance and popularity of renewable energies in Germany increases continuously. In particular, Wind Energy influences the success story of renewable energiesover the last years.

In addition to positive environmental, CO²-saving aspects, Wind Energy can also be supportive and even fundamental in terms of growth and development for Germany's economy. Economic growth indicators such as a rising revenue development, increasing employment rate or a high export volume are representatives for the economic importance of renewable energies and wind energy in particular.