• Energy Research
• Closed Access close
• Restricted close
• Open Source close
• DK close
• Chinese close

A new vibration control device for wind turbines called the ball vibration absorber is proposed in the present paper. The operating principle and calculation method for the vibration control of wind turbines using this device is introduced. The natural frequency of the absorber, as well as the control force on an SDOF system, is firstly derived through Lagrange’s equation. The results are then extended to an MDOF system. By modeling the wind turbine as an MDOF structure, the equation of motion for the wind turbine-damping device system is obtained. The Davenport spectrum is used to simulate the wind loadings both on the tower and the blades of the wind turbine. Reductions in structural response with a ball vibration absorber are examined and a fatigue analysis is also carried out. The simulation results show that as a compact and economical device, the ball vibration absorber is able to effectively eliminate the dynamic response and extend the fatigue life of the wind turbine.

Fossil and other traditional energy have been bringing serious challenges on energy consumption. Making full use of clean and renewable energy becomes the inevitable requirement of social development. With the development of smart grids, micro-networks and the rapidly developing Internet technology, researchers put forward the concept of energy internet synthesizing the energy network and information network, which aims to improve the energy efficiency, realize the mutual complementary of multiple energies, promote the change of energy usage, and provide new paradigm for sustainable energy development. First of all, this paper summarizes the state-of-the-art researches on energy internet in different countries. Then, in the view of optimal operation of energy internet, optimization operation models, communication and data for the optimal operation of energy internet, and the fault propagation mechanism in energy internet optimization operation are investigated. furthermore, this paper points out the significant research direction and the key techniques for the optimization operation of the energy internet, in order to provide a potential help for China's Energy Internet research.

Electric Vehicles (EVs) provide a significant opportunity for reducing the consumption of fossil energies and the emission of carbon dioxide. With more and more electric vehicles integrated in the power systems, it becomes important to study the effects of EV integration on the power systems, especially the low and middle voltage level networks. In the paper, the basic structure and characteristics of the electric vehicles are introduced. The possible impacts of large scale integration of electric vehicles on the power systems especially the advantage to the integration of the renewable energies are discussed. Finally, the research projects related to the large scale integration of electric vehicles into the power systems are introduced, it will provide reference for large scale integration of Electric Vehicles into power grids.