Key technologies analysis of small scale non-grid-connected wind turbines: A review

The aim of this paper is to review the key technologies of current used small-scale non-grid-connected wind turbines and highlight future developments of both technologies and application. First, the key technologies are divided into four main parts: mechanical structure, generator, converter system and control system. The international developments and the latest technologies are presented from the view of the four main parts. Next, this paper analyzes the four main parts of the key technologies in detail. The characteristics of HAWT, VAWT and HVAWT, choosing and designing of a generator, the AC-DC rectifier and DC-DC chopper circuits in the converter system and the MPPT based laws used in the control system are thoroughly discussed in this paper. Then, the application of a small-scale non-gridconnected wind turbines is introduced. The three main ways are roof top, stand alone and built-in. Meanwhile, the concept of the renewable hybrid energy system which consists of a wind energy system, a PV solar system and a diesel generator is proposed. The four parts of the current research results are presented: novel power electronics technologies, advanced simulation software, automatic controller and deep cycle battery bank.