并网风力发电机系统的发展综述

在综述不同类型的风力发电机系统特点的基础上,结合国外风电市场的概况和电网对风电机组的要求,对风电机组类型的发展趋势进行了探讨。按风电机组的控制特点和传动链类型,对不同类型风电机组的原理、优缺点和当前的概况进行介绍,并对永磁同步发电机结构进行了重点分析。其次,对不同类型风力发电系统的经济性和市场应用情况进行了定量比较分析。最后,结合电网对风力发电机组的要求,对并网风力发电系统的发展趋势及其比较标准进行了探讨。

Some Notes on the Dual Leibniz-Hopf algebra

The Leibniz-Hopf algebra is the free associative algebra with one generator in each positive degree and coproduct given by the Cartan formula. Quasi-symmetric functions are a generalisation of symmetric functions [7],and the algebra of quasi-symmetric functions appear as the dual of the Leibniz-Hopf algebra. The Leibniz-Hopf algebra and its dual are word Hopf algebras and play an important role in combinatorics, algebra and topology. We give some properties of words and consider an another view of proof for the antipode in the dual Leibniz-Hopf algebra.